UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): March 11, 2019

X4 Pharmaceuticals, Inc.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (857) 529-8300

Arsanis, Inc.

950 Winter Street, Suite 4500

Waltham, Massachusetts 02451

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company  ☒

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.  ☒

On March 13, 2019, X4 Pharmaceuticals, Inc., formerly Arsanis, Inc. (the “Company”), completed its business combination with X4 Therapeutics, Inc., formerly X4 Pharmaceuticals, Inc. (“X4”), in accordance with the terms of the Agreement and Plan of Merger, dated as of November 26, 2018, as amended on December 20, 2018 and March 8, 2019 (the “Merger Agreement”), by and among the Company, X4 and Artemis AC Corp., a Delaware corporation and a wholly owned subsidiary of the Company (“Merger Sub”), pursuant to which, among other matters, Merger Sub merged with and into X4, with X4 continuing as a wholly owned subsidiary of the Company and the surviving corporation of the merger (the “Merger”). Effective at 5:00 p.m. EST on March 13, 2019, the Company effected a 1-for-6 reverse stock split of its common stock (the “Reverse Stock Split”) and changed its name to “X4 Pharmaceuticals, Inc.” Following the completion of the Merger, the business conducted by the Company became primarily the business conducted by X4, which is a clinical-stage biopharmaceutical company focused on the discovery, development and commercialization of novel therapeutics for the treatment of rare diseases. Unless noted otherwise, all references to share and per share amounts in this Current Report on Form 8-K reflect the Reverse Stock Split.

Under the terms of the Merger Agreement, at the closing of the Merger, the Company issued an aggregate of approximately 25.7 million shares of its common stock to X4 stockholders, based on a common stock exchange ratio of 0.5702 shares of the Company’s common stock for each share of X4 common stock outstanding immediately prior to the Merger and a preferred stock exchange ratio of 0.5702 shares of the Company’s common stock for each share of X4 preferred stock outstanding prior to the Merger, in each case before taking into account of the Reverse Stock Split. The exchange ratios were determined through arm’s-length negotiations between the Company and X4. The Company also assumed all of the outstanding and unexercised stock options and warrants to purchase shares of X4 capital stock, with the number of shares subject to such options or warrants representing the right to purchase a number of shares of the Company’s common stock equal to 0.5702 multiplied by the number of shares of X4 capital stock previously represented by such options or warrants, before taking into account the Reverse Stock Split. The exercise prices of such options and warrants were also appropriately adjusted to reflect the exchange ratio of 0.5702, before taking into account the Reverse Stock Split. As a result of the Reverse Stock Split, the number of shares subject to such options and warrants and the exercise prices of such options and warrants were further adjusted by decreasing the number of shares subject to such options and warrants and increasing the exercise price of such options and warrants on a 1-for-6 Reverse Stock Split basis. The assumed options continue to be governed by the terms of the X4 2015 Employee, Director and Consultant Equity Incentive Plan, as amended, under which the options were originally granted (the “X4 Plan”). Upon the closing of the Merger, the Company also assumed the X4 Plan.

Immediately following the Merger and the Reverse Stock Split, there were approximately 6.7 million shares of the Company’s common stock outstanding, and the former X4 stockholders owned approximately 4.3 million shares, or 63.7% of the Company’s common stock outstanding. In addition, immediately following the Merger and the Reverse Stock Split, the former X4 optionholders held options to purchase approximately 0.8 million shares of the Company’s common stock and the former X4 warrantholders held warrants to purchase approximately 0.5 million shares of the Company’s common stock. Approximately 24.3% of the Company’s common stock outstanding immediately after the Merger is held by stockholders subject to lock-up restrictions, pursuant to which such stockholders have agreed, except in limited circumstances, not to sell or transfer, or engage in swap or similar transactions with respect to, shares of the Company’s common stock, including, as applicable, shares received in the Merger and issuable upon exercise of certain warrants and options, for a period of 180 days following the closing of the Merger.

The shares of the Company’s common stock issued to the former stockholders of X4 were registered with the U.S. Securities and Exchange Commission (the “SEC”) on the Company’s Registration Statement on Form S-4, as amended (File No. 333-228929) (the “Registration Statement”).

The shares of the Company’s common stock listed on The Nasdaq Global Market, previously trading through the close of business on Wednesday, March 13, 2019 under the ticker symbol “ASNS,” will commence trading on The Nasdaq Capital Market, on a post-Reverse Stock Split adjusted basis, under the ticker symbol “XFOR,” on Thursday, March 14, 2019. The Company’s common stock is represented by a new CUSIP number, 98420X103.

The foregoing description of the Merger Agreement contained herein does not purport to be complete and is qualified in its entirety by reference to the Merger Agreement, including the amendments thereto, which are attached hereto as Exhibits 2.1, 2.2 and 2.3 and are incorporated herein by reference.

Item 2.03. Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant.

In October 2018, X4 entered into a loan and security agreement (the “Hercules Loan Agreement”) with Hercules Capital, Inc. (“Hercules”), which provided for aggregate maximum borrowings of up to $13.0 million, consisting of (i) a term loan of up to $8.0 million, which was available upon entering into the agreement, (ii) subject to specified financing conditions, an additional term loan of up to $2.0 million, available for borrowing from January 1, 2019 to March 31, 2019, and (iii) subject to specified financing conditions and the receipt of the second tranche $2.0 million term loan described above, an additional term loan of up to $3.0 million, available for borrowing until March 31, 2019. In October 2018, X4 borrowed $8.0 million under the Hercules Loan Agreement. Borrowings under the Hercules Loan Agreement bear interest at variable rates, with the first tranche bearing interest at a variable rate equal to the greater of (i) 9.5% or (ii) 9.5% plus the Wall Street Journal prime rate minus 5.25%, the second tranche bearing interest at a variable rate, subject to completion of specified financing conditions, equal to either (A) the greater of (i) 9.5% or (ii) 9.5% plus the Wall Street Journal prime rate minus 5.25% or (B) the greater of (i) 8.75% or (ii) 8.75% plus the Wall Street Journal prime rate minus 5.25%, and the third tranche bearing interest at a variable rate equal to the greater of (i) 8.75% or (ii) 8.75% plus the Wall Street Journal prime rate minus 5.25%. In an event of default, as defined in the Hercules Loan Agreement, and until such event is no longer continuing, the interest rate applicable to borrowings under the Hercules Loan Agreement would be increased by 4.0%.

Borrowings under the Hercules Loan Agreement are repayable in monthly interest-only payments through August 2019, or a later date upon achievement of specified conditions, and in equal monthly payments of principal and accrued interest from September 2019 until the maturity date of the loan, which is either (i) November 2021 if the second tranche is not borrowed, or (ii) May 2022 if the second tranche is borrowed. At X4’s option, X4 may prepay all, but not less than all, of the outstanding borrowings, subject to a prepayment premium of up to 2.0% of the principal amount outstanding as of the date of repayment. In addition, the Hercules Loan Agreement provides for a final payment, payable upon maturity or the repayment in full of all obligations under the agreement, of up to $1.0 million.

Borrowings under the Hercules Loan Agreement are collateralized by substantially all of X4’s personal property and other assets, including its intellectual property, until a specified financing condition is met. Under the Hercules Loan Agreement, X4 has agreed to affirmative and negative covenants to which X4 will remain subject until maturity or repayment of the loan in full. The covenants include (a) maintaining a minimum liquidity amount of the lesser of (i) 125% of outstanding borrowings under the Hercules Loan Agreement and (ii) 100% of X4’s cash and cash equivalents in an account in which Hercules has a first priority security interest, as well as (b) restrictions on X4’s ability to incur additional indebtedness, pay dividends, encumber its intellectual property, or engage in certain fundamental business transactions, such as mergers or acquisitions of other businesses. X4’s obligations under the Hercules Loan Agreement are subject to acceleration upon occurrence of specified events of default, including payment default, insolvency and a material adverse change in X4’s business, operations or financial or other condition.

In October 2018, in connection with entering into the Hercules Loan Agreement, X4 issued to the lender warrants for the purchase of 210,638 shares of X4 Series B preferred stock at an exercise price of $1.88 per share, which as a result of the Merger and the Reverse Stock Split, became warrants to purchase approximately 20,017 shares of the Company’s common stock at an exercise price of $19.80 per share. The warrants were immediately exercisable and expire in October 2028.

In December 2018, X4 entered into the First Amendment to the Hercules Loan Agreement (the “First Amendment”), which amended the available borrowing dates of the second tranche from between January 1, 2019 and March 31, 2019 to between December 11, 2018 and December 14, 2018 and amended the term loan maturity date to November 1, 2021. In December 2018, X4 borrowed the additional $2.0 million provided under the First Amendment. In connection with entering into the First Amendment, X4 agreed to issue to the lender warrants to purchase a specified number of shares of X4 preferred stock at an aggregate exercise price of $99,000 at the earliest of

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(a) June 30, 2019, (b) the earlier to occur of (i) the date X4 prepays the outstanding borrowings or (ii) the date the outstanding borrowings become due and payable, or (c) on or before the fifth business day following the closing of or the announcement of the termination of the Merger.

The Company intends to issue a warrant to purchase 5,000 shares of the Company’s common stock with an exercise price of $19.80 per share (the “2019 Hercules Warrant”) to Hercules pursuant to the Hercules Loan Agreement as a result of closing of the Merger. The Company expects that the 2019 Hercules Warrant will be exercisable for a period of 10 years from the date of issuance. The issuance of the 2019 Hercules Warrant is expected to be exempt from registration under Section 4(a)(2) of the Securities Act of 1933, as amended (the “Securities Act”), relating to sales by an issuer not involving any public offering.

The foregoing description of the Hercules Loan Agreement and the First Amendment contained herein does not purport to be complete and is qualified in its entirety by reference to the Hercules Loan Agreement and the First Amendment, which are attached hereto as Exhibits 10.9 and 10.10, respectively, and are incorporated herein by reference.

As disclosed below under Item 5.07, at the special meeting of the Company’s stockholders held on March 11, 2019 (the “Special Meeting”), the Company’s stockholders approved an amendment to the restated certificate of incorporation of the Company (the “Stock Split Amendment”) to effect the Reverse Stock Split of the Company’s common stock, and approved an amendment to the restated certificate of incorporation of the Company (the “Name Change Amendment”) to change the Company’s name from “Arsanis, Inc.” to “X4 Pharmaceuticals, Inc.” (the “Name Change”).

On March 13, 2019, immediately following the closing of the Merger, the Company filed the Stock Split Amendment with the Secretary of State of the State of Delaware to effect the Reverse Stock Split and the Company filed the Name Change Amendment with the Secretary of State of the State of Delaware to effect the Name Change. As a result of the Reverse Stock Split, the number of issued and outstanding shares of the Company’s common stock immediately prior to the Reverse Stock Split was reduced to a smaller number of shares, such that every six shares of the Company’s common stock held by a stockholder immediately prior to the Reverse Stock Split, including shares of the Company’s common stock issued to former X4 stockholders in connection with the Merger, were combined and reclassified into one share of the Company’s common stock. Immediately following the Reverse Stock Split, there were approximately 6.7 million shares of the Company’s common stock outstanding.

No fractional shares were issued in connection with the Reverse Stock Split. Any fractional shares resulting from the Reverse Stock Split were rounded down to the nearest whole number, and each stockholder who would otherwise be entitled to a fraction of a share of common stock upon the Reverse Stock Split (after aggregating all fractions of a share to which such stockholder would otherwise be entitled) is, in lieu thereof, entitled to receive a cash payment determined by multiplying the average closing price per share of Common Stock on the Nasdaq Global Market on the 10 consecutive trading days prior to March 13, 2019, by the fraction of a share of Common Stock to which each stockholder would otherwise be entitled.

The foregoing descriptions of the Stock Split Amendment and the Name Change Amendment are not complete and are subject to and qualified in their entirety by reference to the Stock Split Amendment and the Name Change Amendment, copies of which are attached hereto as Exhibit 3.1 and Exhibit 3.2, respectively, and are incorporated herein by reference.

The information set forth in Item 2.01 of this Current Report on Form 8-K regarding the Merger and the information set forth in Item 5.02 of this Current Report on Form 8-K regarding the Company’s board of directors and executive officers following the Merger are incorporated by reference into this Item 5.01.

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Item 5.02. Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

Directors

In accordance with the Merger Agreement, on March 13, 2019, immediately prior to and effective upon the closing of the Merger, Michael P. Gray, William Clark, M.B.A, Tillman U. Gerngross, Ph.D., Carl Gordon, Ph.D., C.F.A., Terrance McGuire, Claudio Nessi, Ph.D., M.B.A., Michael Ross, Ph.D. and Amy Schulman, J.D. resigned from the Company’s board of directors and committees of the board of directors on which they respectively served, which resignations were not the result of any disagreements with the Company relating to the Company’s operations, policies or practices.

The Merger Agreement provides that at or immediately after the closing of the Merger, the size of the Company’s board of directors will be fixed at seven members consisting of two members designated by the Company, who are David McGirr, M.B.A. and René Russo, Pharm.D., BCPS, and five members designated by X4. In accordance with the Merger Agreement, at the closing of the Merger on March 13, 2019, the board of directors and its committees were reconstituted, with David McGirr, Paula Ragan, Ph.D. and Michael S. Wyzga appointed as Class I directors of the Company whose terms expire at the Company’s 2021 annual meeting of stockholders (with Mr. Wyzga to serve as chairman of the board of directors), René Russo and Isaac Blech appointed as Class II directors of the Company whose terms expire at the Company’s 2019 annual meeting of stockholders, and Gary J. Bridger, Ph.D. appointed as Class III director of the Company whose term expires at the Company’s 2020 annual meeting of stockholders, and with one additional person to be appointed to the Company’s board of directors as a Class III director. In addition, David McGirr, Isaac Blech and Michael S. Wyzga were appointed to the Company’s Audit Committee (with Mr. McGirr continuing to serve as chair of the committee); Isaac Blech and Gary J. Bridger, Ph.D. were appointed to the Company’s Compensation Committee (with Mr. Blech serving as chair of the committee); and Gary J. Bridger, Ph.D., David McGirr and Michael S. Wyzga were appointed to the Company’s Nominating and Corporate Governance Committee (with Dr. Bridger serving as chair of the committee). Each of Drs. Bridger, Ragan and Russo and Messrs. Blech, McGirr and Wyzga entered into an indemnification agreement with the Company on March 13, 2019, immediately following the Merger.

Previously, on November 14, 2017, X4 entered into an independent contractor agreement with Gary J. Bridger, Ph.D., pursuant to which Dr. Bridger agreed to provide X4 with strategic advice in support of X4’s research and development programs in oncology and WHIM syndrome. The agreement provided for an initial term of six months, which was renewed in accordance with its terms for an additional six months and expired in November 2018. The independent contractor agreement included standard assignment of invention, confidentiality and indemnification provisions. In consideration for the provision of consulting services pursuant to the agreement, Dr. Bridger was paid approximately $105,000. On October 4, 2018, X4 entered into a letter agreement with Dr. Bridger, pursuant to which Dr. Bridger agreed to serve as a member of the X4 board of directors. This letter agreement superseded the independent contractor agreement described above. Pursuant to the letter agreement, X4 granted Dr. Bridger an option to purchase 226,983 shares of its common stock to vest pursuant to the terms of the X4 Plan and a separate non-qualified stock option agreement to be entered into by and between X4 and Dr. Bridger. The letter agreement also specified that Dr. Bridger would be entitled to receive an annual grant of an option to purchase shares of X4 common stock at the level set for independent directors by the X4 board of directors, if any. X4 also agreed to reimburse Dr. Bridger for expenses for which he received prior approval from X4. Either X4 or Dr. Bridger may terminate the letter agreement at any time, for any reason, by giving the other 30 days’ prior written notice.

Executive Officers

On March 13, 2019, effective immediately after the closing of the Merger, the Company’s board of directors appointed Paula Ragan, Ph.D. as the Company’s President, Chief Executive Officer and Secretary and Adam S. Mostafa as the Company’s Chief Financial Officer, Treasurer and Assistant Secretary. Each of Dr. Ragan and Mr. Mostafa entered into an indemnification agreement with the Company on March 13, 2019, immediately following the Merger. There are no family relationships among any of the Company’s directors and executive officers.

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These executive officers received the following Company securities in connection with the closing of the Merger:

Paula Ragan, Ph.D. Dr. Ragan, age 48, has been X4’s President and Chief Executive Officer and a member of the X4 board of directors since July 2014. She has more than 18 years of experience building companies in the biotechnology industry. From August 2012 to September 2014, Dr. Ragan consulted as Chief Business Officer at Lysosomal Therapeutics Inc., a private biopharmaceutical company, where she led the company’s business development activities. Prior to that, from January 2007 to August 2012, Dr. Ragan held leadership roles in corporate development and operations at Genzyme Corporation, a Sanofi company, where she led strategic partnering efforts for Genzyme’s Rare Disease business and headed the supply chain planning for Genzyme’s flagship commercial products. Other professional roles include business roles at Hydra Biosciences, Oscient Corporation and Celera Corporation. Dr. Ragan received her B.S. from Tufts University and her Ph.D. from Massachusetts Institute of Technology and completed post-doctoral studies at Harvard Medical School. The Company believes that Dr. Ragan’s perspective and experience as X4’s President and Chief Executive Officer, which provides the board with historic knowledge, operational expertise and continuity, provides her with the qualifications and skills to serve on the Company’s board of directors.

On March 13, 2019, in connection with the closing of the Merger, X4 entered into an amended and restated executive employment agreement (the “CEO Agreement”) with Paula Ragan, Ph.D., pursuant to which Dr. Ragan agreed to continue serving as X4’s Chief Executive Officer. Pursuant to the CEO Agreement, Dr. Ragan’s compensation consists of base salary at an annual rate approved by the board of directors or an appropriate committee thereof, an annual bonus as determined by the board of directors, but not less than 25% of Dr. Ragan’s base salary, fringe benefits, vacation, reimbursement of ordinary and reasonable out-of-pocket expenses and coverage under X4’s Directors’ and Officers’ (“D&O”) insurance policies, subject to the terms and conditions of such policies. Dr. Ragan’s base salary is currently equal to $520,000, with an annual target bonus set at 50% of base salary, subject to review and adjustment each year by the board of directors.

If Dr. Ragan’s employment is terminated for any reason, Dr. Ragan will be entitled to receive her accrued but unpaid salary, accrued but unused vacation days, the amount of any properly incurred expenses prior to termination not yet reimbursed and other benefits. In addition to the foregoing, if Dr. Ragan’s employment is terminated by X4 without cause or if Dr. Ragan resigns for good reason, each term as defined in the CEO Agreement, Dr. Ragan will be entitled to the following: (a) a continuation of base salary for 12 months, (b) a pro-rata portion of Dr. Ragan’s at-target annual bonus for the calendar year in which the termination occurs based on the period worked by Dr. Ragan during such calendar year prior to termination, (c) so long as Dr. Ragan is eligible for coverage under X4’s health insurance plan, elects coverage, was covered prior to termination, and elects to exercise her rights under COBRA to continue participation in such plan, X4 will pay the normal share of costs under such plan until the earlier of 12 months from the date of Dr. Ragan’s termination, or the date Dr. Ragan is eligible to receive health benefits through another employer, and (d) Dr. Ragan will become vested in the additional number of outstanding time-based equity awards granted to Dr. Ragan by X4 that would have otherwise vested had Dr. Ragan remained employed for an additional 12 months after her termination date. In addition, if Dr. Ragan’s employment is terminated without cause or if Dr. Ragan resigns for good reason within the one year period following a change of control, as that term is defined in the CEO Agreement, Dr. Ragan will be entitled to automatic vesting in all outstanding time-based equity awards granted to Dr. Ragan by X4, subject to the terms and conditions of the CEO Agreement. Dr. Ragan agrees to continue to abide by the terms of her non-competition, non-solicitation, non-disclosure and intellectual property agreement.

The foregoing description of the CEO Agreement contained herein does not purport to be complete and is qualified in its entirety by reference to the CEO Agreement, which is attached hereto as Exhibit 10.3 and is incorporated herein by reference.

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Adam S. Mostafa. Adam S. Mostafa, age 39, has served as X4’s Chief Financial Officer since September 2018. Prior to joining X4, Mr. Mostafa served as chief financial officer of Abpro Corporation, a biotechnology company focused on antibody therapeutics, from June 2016 to August 2018. Prior to that, Mr. Mostafa was a managing director in the healthcare investment banking group at Cantor Fitzgerald from January 2015 to May 2016, and from June 2011 to January 2015, Mr. Mostafa was a senior banker in the healthcare investment banking group at Needham & Company. Prior to that, Mr. Mostafa was a vice president in the investment banking group at CRT Capital Group from March 2007 to May 2011, and from September 2003 to March 2007, Mr. Mostafa was a portfolio management associate in the global stock selection group at AQR Capital. Mr. Mostafa began his career as an analyst in the healthcare investment banking group at Salomon Smith Barney. Mr. Mostafa earned an A.B. in Economics from Brown University.

On March 13, 2019, in connection with the closing of the Merger, X4 entered into an amended and restated executive employment agreement (the “CFO Agreement”) with Adam S. Mostafa, pursuant to which Mr. Mostafa agreed to continue serving as X4’s Chief Financial Officer. Pursuant to the CFO Agreement, Mr. Mostafa’s compensation consists of base salary at an annual rate approved by the board if directors or an appropriate committee thereof, an annual bonus as determined by the board of directors but not less than 25% of Mr. Mostafa’s base salary, fringe benefits, vacation, reimbursement of ordinary and reasonable out-of-pocket expenses and coverage under X4’s D&O insurance policies, subject to the terms and conditions of such policies. Mr. Mostafa’s base salary is currently equal to $380,000, with an annual target bonus set at 40% of base salary, subject to review and adjustment each year by the board of directors.

If Mr. Mostafa’s employment is terminated for any reason, Mr. Mostafa is entitled to receive his accrued but unpaid salary, accrued but unused vacation days, the amount of any properly incurred expenses prior to termination not yet reimbursed and other benefits. In addition to the foregoing, if Mr. Mostafa’s employment is terminated by X4 without cause or if Mr. Mostafa resigns for good reason, each term as defined in the CFO Agreement, Mr. Mostafa will be entitled to the following: (a) a continuation of base salary for six months, (b) a pro-rata portion of Mr. Mostafa’s at-target annual bonus for the calendar year in which the termination occurs based on the period worked by Mr. Mostafa during such calendar year prior to termination, (c) so long as Mr. Mostafa is eligible for coverage under X4’s health insurance plan, elects coverage, was covered prior to termination, and elects to exercise his rights under COBRA to continue participation in such plan, X4 will pay the normal share of costs under such plan until the earlier of six months from the date of Mr. Mostafa’s termination or the date Mr. Mostafa is eligible to receive health benefits through another employer, and (d) Mr. Mostafa will become vested in the additional number of outstanding time-based equity awards granted to Mr. Mostafa by X4 that would have otherwise vested had Mr. Mostafa remained employed for an additional six months after his termination date. In addition, if Mr. Mostafa’s employment is terminated without cause or if Mr. Mostafa resigns for good reason within the one year period following a change of control, as that term is defined in the CFO Agreement, Mr. Mostafa will be entitled to automatic vesting in all outstanding time-based equity awards granted to Mr. Mostafa by X4, subject to the terms and conditions of the CFO Agreement. Mr. Mostafa agrees to continue to abide by the terms of his non-competition, non-solicitation, non-disclosure and intellectual property agreement.

The foregoing description of the CFO Agreement contained herein does not purport to be complete and is qualified in its entirety by reference to the CFO Agreement, which is attached hereto as Exhibit 10.4 and is incorporated herein by reference.

Director Compensation Policy

On March 13, 2019, the Company adopted a director compensation policy based on Arsanis’s existing director compensation program. Pursuant to the policy, the annual retainer for non-employee directors is $35,000 and the annual retainer for the chair of the board of directors is $75,000. Annual retainers for committee membership are as follows:

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These fees are payable in arrears in four equal quarterly installments on the last day of each quarter, provided that the amount of such payment will be prorated for any portion of such quarter that a director is not serving on the Company’s board of directors, on such committee or in such position. Non-employee directors are also reimbursed for reasonable out-of-pocket business expenses incurred in connection with attending meetings of the board of directors and any committee of the board of directors on which they serve and in connection with other business related to the board of directors. Directors may also be reimbursed for reasonable out-of-pocket business expenses authorized by the board of directors or a committee that are incurred in connection with attending conferences or meetings with management in accordance with a travel policy, as may be in effect from time to time.

In addition to the above fees, the board of directors may determine that additional committee fees are appropriate and should be payable for any newly created committee of the board of directors.

In addition, the Company grants to new non-employee directors upon their initial election to the board of directors, an option to purchase 6,854 shares of the Company’s common stock at an exercise price equal to the closing price of the Company’s common stock on the date of grant. Each of these options has a term of 10 years from the date of the award and vests as to 33.3333% of the shares of common stock underlying such option on the first anniversary of the date of grant, with the remainder vesting in equal monthly installments of 2.7777% of the shares of common stock underlying such option until the 36-month anniversary of the date of grant, subject to the non-employee director’s continued service as a director. This vesting accelerates as to 100% of the shares upon a change in control of the Company.

Further, on the dates of each of the Company’s annual meetings of stockholders, each non-employee director that has served on the Company’s board of directors for at least six months automatically receives an option to purchase 3,427 shares of the Company’s common stock at an exercise price equal to the closing price of the Company’s common stock on the date of the grant. Each of these options has a term of 10 years from the date of the award and vests in equal monthly installments of 8.333% of the shares of the Company’s common stock underlying such option until the 12-month anniversary of the date of grant (or, if earlier, the date of the Company’s next annual meeting of stockholders following the date of grant) unless otherwise provided at the time of grant, subject to the non-employee director’s continued service as a director, with 100% acceleration of vesting upon a change in control of the Company.

The foregoing description of the director compensation policy is not complete and is subject to and qualified in its entirety by reference to the director compensation policy, a copy of which is attached hereto as Exhibit 10.2 and is incorporated herein by reference.

X4 2015 Employee, Director and Consultant Equity Incentive Plan

The X4 Plan has been assumed by the Company such that stock options and other equity-based awards are available for future grant with respect to 180,996 shares of the Company’s common stock (which reflects the 1,904,561 shares of X4 common stock available for grant thereunder as of immediately prior to the effective time of the Merger, as adjusted for the common stock exchange ratio and the Reverse Stock Split).

Resignation of Named Executive Officer

On March 13, 2019, immediately prior to and effective upon the closing of the Merger, Michael P. Gray, the Company’s President, Chief Executive Officer and Chief Financial Officer, resigned as an officer of the Company. In connection with the resignation of his employment, Mr. Gray is entitled to certain severance payments and benefits and certain of his outstanding options and restricted stock will automatically vest in full, and the period during which he can exercise certain options will be automatically extended, in each case as described in Mr. Gray’s amended and restated employment agreement. For additional information regarding these payments and benefits, please refer to “The Merger - Interests of the Arsanis Directors and Executive Officers in the Merger - Merger-Related Compensation of Executive Officers” on pages 174-178 of the Registration Statement.

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To the extent required by Item 5.03 of Form 8-K, the information contained in Item 2.01 and Item 3.03 of this Current Report on Form 8-K is incorporated by reference herein.

The Company convened and adjourned its special meeting of stockholders on March 11, 2019 (the “Special Meeting”). At the Special Meeting, 12,635,982 shares of common stock prior to the Reverse Stock Split, or approximately 86.7% of the shares of the Company’s common stock outstanding and entitled to vote at the Special Meeting, were present in person or represented by proxy. At the Special Meeting, the stockholders of the Company voted as set forth below on Proposals No. 1 through 5, each of which is described in detail in the Registration Statement.

The final voting results for each matter submitted to a vote of the Company’s stockholders, which share amounts do not reflect the Reverse Stock Split, are as follows:

Proposal No. 1. Approval of the Merger Agreement.

Proposal to approve the Merger Agreement, by and among the Company, X4 and Merger Sub, and the transactions contemplated thereby, including the merger and the issuance of shares of Company common stock to X4’s stockholders pursuant to the terms of the Merger Agreement:

Proposal No. 2. Approval of the Amendment to the Restated Certificate of Incorporation of the Company to Effect the Reverse Stock Split.

Proposal to approve an amendment to the Company’s restated certificate of incorporation effecting a reverse stock split of Company common stock at a ratio mutually agreed to between the Company and X4 in the range of one new share for every four (4) to eight (8) shares outstanding (or any number in between):

Proposal No. 3. Approval of the Amendment to the Restated Certificate of Incorporation of the Company to Effect the Name Change.

Proposal to approve an amendment to the Company’s restated certificate of incorporation changing the Company’s corporate name from “Arsanis, Inc.” to “X4 Pharmaceuticals, Inc.”:

Proposal No. 4. Approval of the Potential Financing.

Proposal to approve, for purposes of Nasdaq Listing Rules 5635(a), (b) and (d), the sale of up to 45.0 million shares of the Company’s common stock, and/or securities convertible into or exercisable for shares of the Company’s common stock, in the aggregate (subject to adjustment for any stock split, recapitalization or reverse stock split (including the Reverse Stock Split) effected prior to the offerings), for gross proceeds of up to $60.0 million with a maximum 30.0% effective discount to the market price of the Company’s common stock at the time of entering into binding agreement(s) for the issuance:

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Proposal No. 5. Approval of Possible Adjournment of the Special Meeting.

Proposal to consider and vote upon an adjournment of the Special Meeting, if necessary, to solicit additional proxies if there are not sufficient votes in favor of Proposal Nos. 1, 2, 3 or 4:

Item 8.01. Other Events.

On March 13, 2019, the Company issued a press release announcing the completion of the Merger, the Reverse Stock Split and the Name Change. A copy of the press release is attached as Exhibit 99.1 to this Current Report on Form 8-K.

Item 9.01. Financial Statements and Exhibits.

The Company intends to file the financial statements of X4 required by Item 9.01(a) as part of an amendment to this Current Report on Form 8-K not later than 71 calendar days after the date this Current Report on Form 8-K is required to be filed.

The Company intends to file the pro forma financial information required by Item 9.01(b) as part of an amendment to this Current Report on Form 8-K not later than 71 calendar days after the date this Current Report on Form 8-K is required to be filed.

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Exhibit 3.1

CERTIFICATE OF AMENDMENT OF THE RESTATED

CERTIFICATE OF INCORPORATION OF ARSANIS, INC.

(Pursuant to Section 242 of the

General Corporation Law of the State of Delaware)

Arsanis, Inc. (the “Corporation”), a corporation organized and existing under and by virtue of the provisions of the General Corporation Law of the State of Delaware (the “General Corporation Law”),

DOES HEREBY CERTIFY:

1. A resolution was duly adopted by the Board of Directors of the Corporation pursuant to Section 242 of the General Corporation Law proposing this Amendment of the Corporation’s Restated Certificate of Incorporation and declaring the advisability of this Amendment of the Restated Certificate of Incorporation and authorizing the appropriate officers of the Corporation to solicit the consent of the stockholders therefor, which resolution setting forth the proposed amendment is as follows:

RESOLVED, that the first paragraph of Article FOURTH of the Restated Certificate of Incorporation of the Corporation, as amended, be and hereby is deleted in its entirety and the following paragraphs are inserted in lieu thereof:

“FOURTH. Effective as of 5:00 p.m. on March 13, 2019 (the “Effective Time”), a one-for-six reverse stock split of the Corporation’s common stock, par value $0.001 per share (the “Common Stock”), shall become effective, pursuant to which each six shares of Common Stock outstanding and held of record by each stockholder of the Corporation (including treasury shares) immediately prior to the Effective Time shall be reclassified and combined into one validly issued, fully paid and nonassessable share of Common Stock automatically and without any action by the holder thereof upon the Effective Time and shall represent one share of Common Stock from and after the Effective Time (such reclassification and combination of shares, the “Reverse Stock Split”). The par value of the Common Stock following the Reverse Stock Split shall remain at $0.001 per share. No fractional shares of Common Stock shall be issued as a result of the Reverse Stock Split and, in lieu thereof, upon surrender after the Effective Time of a certificate which formerly represented shares of Common Stock that were issued and outstanding immediately prior to the Effective Time, any person who would otherwise be entitled to a fractional share of Common Stock as a result of the Reverse Stock Split, following the Effective Time, shall be entitled to receive a cash payment equal to the fraction of a share of Common Stock to which such holder would otherwise be entitled multiplied by the fair value per share of the Common Stock immediately prior to the Effective Time as determined by the Board of Directors of the Corporation.

Each stock certificate that, immediately prior to the Effective Time, represented shares of Common Stock that were issued and outstanding immediately prior to the Effective Time shall, from and after the Effective Time, automatically and without the necessity of presenting the same for exchange, represent that number of whole shares of Common Stock after the Effective Time into which the shares formerly represented by such certificate have been reclassified (as well as the right to receive cash in lieu of fractional shares of Common Stock after the Effective Time); provided, however, that each person of record holding a certificate that represented shares of Common Stock that were issued and outstanding immediately prior to the Effective Time shall receive, upon surrender of such certificate, a new certificate evidencing and representing the number of whole shares of Common Stock after the Effective Time into which the shares of Common Stock formerly represented by such certificate shall have been reclassified.

The total number of shares of all classes of stock which the Corporation shall have authority to issue is 43,333,333 shares, consisting of (i) 33,333,333 shares of Common Stock, $0.001 par value per

share (“Common Stock”), and (ii) 10,000,000 shares of Preferred Stock, $0.001 par value per share (“Preferred Stock”).”

2. This Certificate of Amendment of the Restated Certificate of Incorporation has been duly adopted by the stockholders of the Corporation in accordance with the provisions of Section 242 of the General Corporation Law.

[Remainder of page intentionally blank]

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IN WITNESS WHEREOF, this Corporation has caused this Certificate of Amendment of the Restated Certificate of Incorporation to be signed by its President and Chief Executive Officer this 13th day of March, 2019.

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Exhibit 3.2

CERTIFICATE OF AMENDMENT OF THE RESTATED

CERTIFICATE OF INCORPORATION OF ARSANIS, INC.

(Pursuant to Section 242 of the

General Corporation Law of the State of Delaware)

Arsanis, Inc. (the “Corporation”), a corporation organized and existing under and by virtue of the provisions of the General Corporation Law of the State of Delaware (the “General Corporation Law”),

DOES HEREBY CERTIFY:

1. A resolution was duly adopted by the Board of Directors of the Corporation pursuant to Section 242 of the General Corporation Law proposing this Amendment of the Corporation’s Restated Certificate of Incorporation and declaring the advisability of this Amendment of the Restated Certificate of Incorporation and authorizing the appropriate officers of the Corporation to solicit the consent of the stockholders therefor, which resolution setting forth the proposed amendment is as follows:

RESOLVED, that Article FIRST of the Restated Certificate of Incorporation of the Corporation, as amended, be and hereby is deleted in its entirety and the following is inserted in lieu thereof:

“FIRST: Effective immediately upon the filing of this Certificate of Amendment of the Restated Certificate of Incorporation with the Secretary of State of the State of Delaware, the name of the Corporation is X4 Pharmaceuticals, Inc.”

2. This Certificate of Amendment of the Restated Certificate of Incorporation has been duly adopted by the stockholders of the Corporation in accordance with the provisions of Section 242 of the General Corporation Law.

[Remainder of page intentionally blank]

IN WITNESS WHEREOF, this Corporation has caused this Certificate of Amendment of the Restated Certificate of Incorporation to be signed by its President and Chief Executive Officer this 13th day of March, 2019.

Exhibit 4.1

THIS CERTIFIES THAT is the owner of CUSIP DATED COUNTERSIGNED AND REGISTERED: COMPUTERSHARE TRUST COMPANY, N.A. TRANSFER AGENT AND REGISTRAR, FULLY-PAID AND NON-ASSESSABLE SHARES OF COMMON STOCK OF X4 Pharmaceuticals, Inc. (hereinafter called the "Company"), transferable on the books of the Company in person or by duly authorized attorney, upon surrender of this Certificate properly endorsed. This Certificate and the shares represented hereby, are issued and shall be held subject to all of the provisions of the Certificate of Incorporation, as amended, and the By-Laws, as amended, of the Company (copies of which are on file with the Company and with the Transfer Agent), to all of which each holder, by acceptance hereof, assents. This Certificate is not valid unless countersigned and registered by the Transfer Agent and Registrar. Witness the facsimile seal of the Company and the facsimile signatures of its duly authorized officers. COMMON STOCK PAR VALUE $0.001 COMMON STOCK SEE REVERSE FOR CERTAIN DEFINITIONS Certificate Number Shares . X4 PHARMACEUTICALS, INC. INCORPORATED UNDER THE LAWS OF THE STATE OF DELAWARE President Treasurer By AUTHORIZED SIGNATURE August 2, 2010 DELAWARE CO R PO RATE X4 PHARMACEUTICALS, INC. ZQ|CERT#|COY|CLS|RGSTRY|ACCT#|TRANSTYPE|RUN#|TRANS# 98420X 10 3 DD-MMM-YYYY * * 000000* * * * * * * * * * * * * * * * * * * * * 000000* * * * * * * * * * * * * * * * * * * * * 000000* * * * * * * * * * * * * * * * * * * * * 000000* * * * * * * * * * * * * * * * * * * * * 000000* * * * * * * * * * * * * * ** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Sample **** Mr. Sample **000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares*** *000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares**** 000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****0 00000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****00 0000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000 000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****0000 00**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****00000 0**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000 **Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000* *Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000** Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**S ***ZERO HUNDRED THOUSAND ZERO HUNDRED AND ZERO*** MR. SAMPLE & MRS. SAMPLE & MR. SAMPLE & MRS. SAMPLE ZQ00000000 Certificate Numbers 1234567890/1234567890 1234567890/1234567890 1234567890/1234567890 1234567890/1234567890 1234567890/1234567890 1234567890/1234567890 Total Transaction Num/No. 123456 Denom. 123456 Total 1234567 MR A SAMPLE DESIGNATION (IF ANY) ADD 1 ADD 2 ADD 3 ADD 4 955 Massachusetts Avenue, 4th Floor, Cambridge, MA 02139 CUSIP/IDENTIFIER 98420X 10 3 Holder ID XXXXXXXXXX Insurance Value 1,000,000.00 Number of Shares 123456 DTC 12345678 123456789012345 THIS CERTIFICATE IS TRANSFERABLE IN CITIES DESIGNATED BY THE TRANSFER AGENT, AVAILABLE ONLINE AT www.computershare.com

The IRS requires that the named transfer agent (“we”) report the cost basis of certain shares or units acquired after January 1, 2011. If your shares or units are covered by the legislation, and you requested to sell or transfer the shares or units using a specific cost basis calculation method, then we have processed as you requested. If you did not specify a cost basis calculation method, then we have defaulted to the first in, first out (FIFO) method. Please consult your tax advisor if you need additional information about cost basis. If you do not keep in contact with the issuer or do not have any activity in your account for the time period specified by state law, your property may become subject to state unclaimed property laws and transferred to the appropriate state. For value received, hereby sell, assign and transfer unto Shares Attorney Dated: 20Signature:Signature: Notice: The signature to this assignment must correspond with the name as written upon the face of the certificate, in every particular, without alteration or enlargement, or any change whatever. PLEASE INSERT SOCIAL SECURITY OR OTHER IDENTIFYING NUMBER OF ASSIGNEE (PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS, INCLUDING POSTAL ZIP CODE, OF ASSIGNEE) of the common stock represented by the within Certificate, and do hereby irrevocably constitute and appoint to transfer the said stock on the books of the within-named Incorporation with full power of substitution in the premises. . X4 PHARMACEUTICALS, INC. THE COMPANY WILL FURNISH WITHOUT CHARGE TO EACH SHAREHOLDER WHO SO REQUESTS, A SUMMARY OF THE POWERS, DESIGNATIONS, PREFERENCES AND RELATIVE, PARTICIPATING, OPTIONAL OR OTHER SPECIAL RIGHTS OF EACH CLASS OF STOCK OF THE COMPANY AND THE QUALIFICATIONS, LIMITATIONS OR RESTRICTIONS OF SUCH PREFERENCES AND RIGHTS, AND THE VARIATIONS IN RIGHTS, PREFERENCES AND LIMITATIONS DETERMINED FOR EACH SERIES, WHICH ARE FIXED BY THE CERTIFICATE OF INCORPORATION OF THE COMPANY, AS AMENDED, AND THE RESOLUTIONS OF THE BOARD OF DIRECTORS OF THE COMPANY, AND THE AUTHORITY OF THE BOARD OF DIRECTORS TO DETERMINE VARIATIONS FOR FUTURE SERIES. SUCH REQUEST MAY BE MADE TO THE OFFICE OF THE SECRETARY OF THE COMPANY OR TO THE TRANSFER AGENT. THE BOARD OF DIRECTORS MAY REQUIRE THE OWNER OF A LOST OR DESTROYED STOCK CERTIFICATE, OR HIS LEGAL REPRESENTATIVES, TO GIVE THE COMPANY A BOND TO INDEMNIFY IT AND ITS TRANSFER AGENTS AND REGISTRARS AGAINST ANY CLAIM THAT MAY BE MADE AGAINST THEM ON ACCOUNT OF THE ALLEGED LOSS OR DESTRUCTION OF ANY SUCH CERTIFICATE. Signature(s) Guaranteed: Medallion Guarantee Stamp THE SIGNATURE(S) SHOULD BE GUARANTEED BY AN ELIGIBLE GUARANTOR INSTITUTION (Banks, Stockbrokers, Savings and Loan Associations and Credit Unions) WITH MEMBERSHIP IN AN APPROVED SIGNATURE GUARANTEE MEDALLION PROGRAM, PURSUANT TO S.E.C. RULE 17Ad-15. The following abbreviations, when used in the inscription on the face of this certificate, shall be construed as though they were written out in full according to applicable laws or regulations: TEN COM—as tenants in common UNIF GIFT MIN ACT ............................................ Custodian................................................ (Cust) (Minor) TEN ENT—as tenants by the entireties under Uniform Gifts to Minors Act........................................................ (State) JT TEN—as joint tenants with right of survivorship UNIF TRF MIN ACT -............................................ Custodian (until age................................ ) and not as tenants in common (Cust) ............................. under Uniform Transfers to Minors Act................... (Minor) (State) Additional abbreviations may also be used though not in the above list.

Exhibit 4.2

THIS WARRANT AND THE SHARES ISSUABLE HEREUNDER HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “ACT”), OR THE SECURITIES LAWS OF ANY STATE AND, EXCEPT AS SET FORTH IN SECTIONS 5.3 AND 5.4 BELOW, MAY NOT BE OFFERED, SOLD, PLEDGED OR OTHERWISE TRANSFERRED UNLESS AND UNTIL REGISTERED UNDER SAID ACT AND LAWS OR, IN THE OPINION OF LEGAL COUNSEL IN FORM AND SUBSTANCE SATISFACTORY TO THE ISSUER, SUCH OFFER, SALE, PLEDGE OR OTHER TRANSFER IS EXEMPT FROM SUCH REGISTRATION.

WARRANT TO PURCHASE STOCK

Company: X4 Pharmaceuticals, Inc., a Delaware corporation

Number of Shares: As set forth in Paragraph A below

Type/Series of Stock: Series A Preferred Stock, $0.001 par value per share

Warrant Price: $1.88 per Share, subject to adjustment as set forth herein

Issue Date: October 25, 2016

Expiration Date: October 24, 2026 See also Section 5.1(b).

THIS WARRANT CERTIFIES THAT, for good and valuable consideration, [SILICON VALLEY BANK / LIFE SCIENCE LOANS, LLC] (together with any successor or permitted assignee or transferee of this Warrant or of any shares issued upon exercise hereof, “Holder”) is entitled to purchase up to such number of fully paid and non-assessable shares of the above-stated Type/Series of Stock (the “Class”) of the above-named company (the “Company”) as determined pursuant to Paragraph A below, at the above-stated Warrant Price, all as set forth above and as adjusted pursuant to Section 2 of this Warrant, subject to the provisions and upon the terms and conditions set forth in this Warrant. [Reference is made to Section 5.4 of this Warrant whereby Silicon Valley Bank shall transfer this Warrant to its parent company, SVB Financial Group.]

A.    Number of Shares. This Warrant shall be exercisable for the Initial Shares, plus the Additional Shares, if any (collectively, and as may be adjusted from time to time in accordance with the provisions of this Warrant, the “Shares”).

(1)    Initial Shares. As used herein “Initial Shares” means 27,128 shares of the Class, subject to adjustment from time to time in accordance with the provisions of this Warrant.

(2)    Additional Shares. Upon the making, if any, of the Term B Loan Advance (as defined in the Loan Agreement) to the Company in any amount, this Warrant automatically shall become exercisable for an additional 18,085 shares of the Class, as such number may be adjusted from time to time in accordance with the provisions of this Warrant (the “Additional Shares”), including, without limitation, adjustments in respect of events occurring prior to the

date, if any, on which this Warrant becomes exercisable for the Additional Shares as if they constituted “Shares” hereunder at all times from and after the Issue Date.

SECTION 1. EXERCISE.

1.1    Method of Exercise. Holder may at any time and from time to time exercise this Warrant, in whole or in part, by delivering to the Company the original of this Warrant together with a duly executed Notice of Exercise in substantially the form attached hereto as Appendix 1 and, unless Holder is exercising this Warrant pursuant to a cashless exercise set forth in Section 1.2, a check, wire transfer of same-day funds (to an account designated by the Company), or other form of payment acceptable to the Company for the aggregate Warrant Price for the Shares being purchased.

1.2    Cashless Exercise. On any exercise of this Warrant, in lieu of payment of the aggregate Warrant Price in the manner as specified in Section 1.1 above, but otherwise in accordance with the requirements of Section 1.1, Holder may elect to receive Shares equal to the value of this Warrant, or portion hereof as to which this Warrant is being exercised. Thereupon, the Company shall issue to the Holder such number of fully paid and non-assessable Shares as are computed using the following formula:

where:

1.3    Fair Market Value. If the Company’s common stock is then traded or quoted on a nationally recognized securities exchange, inter-dealer quotation system or over-the-counter market (a “Trading Market”) and the Class is common stock, the fair market value of a Share shall be the closing price or last sale price of a share of common stock reported for the Business Day immediately before the date on which Holder delivers this Warrant together with its Notice of Exercise to the Company. If the Company’s common stock is then traded in a Trading Market and the Class is a series of the Company’s convertible preferred stock, the fair market value of a Share shall be the closing price or last sale price of a share of the Company’s common stock reported for the Business Day immediately before the date on which Holder delivers this Warrant together with its Notice of Exercise to the Company multiplied by the number of shares of the Company’s common stock into which a Share is then convertible. If the Company’s common stock is not traded in a Trading Market, the Board of Directors of the Company shall determine the fair market value of a Share in its reasonable good faith judgment.

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1.4    Delivery of Certificate and New Warrant. Within a reasonable time after Holder exercises this Warrant in the manner set forth in Section 1.1 or 1.2 above, the Company shall deliver to Holder a certificate representing the Shares issued to Holder upon such exercise and, if this Warrant has not been fully exercised and has not expired, a new warrant of like tenor representing the Shares not so acquired.

1.5    Replacement of Warrant. On receipt of evidence reasonably satisfactory to the Company of the loss, theft, destruction or mutilation of this Warrant and, in the case of loss, theft or destruction, on delivery of an indemnity agreement reasonably satisfactory in form, substance and amount to the Company or, in the case of mutilation, on surrender of this Warrant to the Company for cancellation, the Company shall, within a reasonable time, execute and deliver to Holder, in lieu of this Warrant, a new warrant of like tenor and amount.

1.6    Treatment of Warrant Upon Acquisition of Company.

(a)    Acquisition. For the purpose of this Warrant, “Acquisition” means any transaction or series of related transactions involving: (i) the sale, lease, exclusive license, or other disposition of all or substantially all of the assets of the Company; (ii) any merger or consolidation of the Company into or with another person or entity (other than a merger or consolidation effected exclusively to change the Company’s domicile), or any other corporate reorganization, in which the stockholders of the Company in their capacity as such immediately prior to such merger, consolidation or reorganization, own less than a majority of the Company’s (or the surviving or successor entity’s) outstanding voting power immediately after such merger, consolidation or reorganization (or, if such Company stockholders beneficially own a majority of the outstanding voting power of the surviving or successor entity as of immediately after such merger, consolidation or reorganization, such surviving or successor entity is not the Company); or (iii) any sale or other transfer by the stockholders of the Company of shares representing at least a majority of the Company’s then-total outstanding combined voting power.

(b)    Treatment of Warrant at Acquisition. In the event of an Acquisition in which the consideration to be received by the Company’s stockholders consists solely of cash, solely of Marketable Securities or a combination of cash and Marketable Securities (a “Cash/Public Acquisition”), and the fair market value of one Share as determined in accordance with Section 1.3 above would be greater than the Warrant Price in effect on such date immediately prior to such Cash/Public Acquisition, and Holder has not exercised this Warrant pursuant to Section 1.1 above as to all Shares, then this Warrant shall automatically be deemed to be Cashless Exercised pursuant to Section 1.2 above as to all Shares effective immediately prior to and contingent upon the consummation of a Cash/Public Acquisition. In connection with such Cashless Exercise, Holder shall be deemed to have restated each of the representations and warranties in Section 4 of the Warrant as of the date thereof and the Company shall promptly notify the Holder of the number of Shares (or such other securities) issued upon exercise. In the event of a Cash/Public Acquisition where the fair market value of one Share as determined in accordance with Section 1.3 above would be less than the Warrant Price in effect immediately prior to such Cash/Public Acquisition, then this Warrant will expire immediately prior to the consummation of such Cash/Public Acquisition.

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(c)    Upon the closing of any Acquisition other than a Cash/Public Acquisition, the acquiring, surviving or successor entity shall assume the obligations of this Warrant, and this Warrant shall thereafter be exercisable for the same securities and/or other property as would have been paid for the Shares issuable upon exercise of the unexercised portion of this Warrant as if such Shares were outstanding on and as of the closing of such Acquisition, subject to further adjustment from time to time in accordance with the provisions of this Warrant.

(d)    As used in this Warrant “Marketable Securities” means securities meeting all of the following requirements: (i) the issuer thereof is then subject to the reporting requirements of Section 13 or Section 15(d) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and is then current in its filing of all required reports and other information under the Act and the Exchange Act; (ii) the class and series of shares or other security of the issuer that would be received by Holder in connection with the Acquisition were Holder to exercise this Warrant on or prior to the closing thereof is then traded in a Trading Market, and (iii) following the closing of such Acquisition, Holder would not be restricted from publicly re-selling all of the issuer’s shares and/or other securities that would be received by Holder in such Acquisition were Holder to exercise this Warrant in full on or prior to the closing of such Acquisition, except to the extent that any such restriction (x) arises solely under federal or state securities laws, rules or regulations, and (y) does not extend beyond six (6) months from the closing of such Acquisition.

1.7    Voting Agreement. Upon any exercise of this Warrant, Holder shall, if the Company so requests in writing, become a party to, by execution and delivery to the Company of a counterpart signature page, joinder agreement, instrument of accession or similar instrument, that certain Amended and Restated Voting Agreement, dated August 15, 2015 by and among the Company and the other parties thereto and the other parties thereto, as amended and/or restated and in effect from time to time (the “Voting Agreement”), solely with respect to the Shares issued upon such exercise (and the shares of common stock, if any, issued upon conversion of such Shares), solely to the extent that all holders of outstanding shares of the Class are then parties thereto, and solely to the extent that such agreement is then by its terms in force and effect.

SECTION 2. ADJUSTMENTS TO THE SHARES AND WARRANT PRICE.

2.1    Stock Dividends, Splits, Etc. If the Company declares or pays a dividend or distribution on the outstanding shares of the Class payable in common stock or other securities or property (other than cash), then upon exercise of this Warrant, for each Share acquired, Holder shall receive, without additional cost to Holder, the total number and kind of securities and property which Holder would have received had Holder owned the Shares of record as of the date the dividend or distribution occurred. If the Company subdivides the outstanding shares of the Class by reclassification or otherwise into a greater number of shares, the number of Shares purchasable hereunder shall be proportionately increased and the Warrant Price shall be proportionately decreased. If the outstanding shares of the Class are combined or consolidated, by reclassification or otherwise, into a lesser number of shares, the Warrant Price shall be proportionately increased and the number of Shares shall be proportionately decreased.

2.2    Reclassification, Exchange Combinations or Substitution. Upon any event whereby all of the outstanding shares of the Class are reclassified, exchanged, combined, substituted, or replaced for, into, with or by Company securities of a different class and/or series,

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then from and after the consummation of such event, this Warrant will be exercisable for the number, class and series of Company securities that Holder would have received had the Shares been outstanding on and as of the consummation of such event, and subject to further adjustment thereafter from time to time in accordance with the provisions of this Warrant. The provisions of this Section 2.2 shall similarly apply to successive reclassifications, exchanges, combinations, substitutions, replacements or other similar events.

2.3    Conversion of Preferred Stock. If the Class is a class and series of the Company’s convertible preferred stock, in the event that all outstanding shares of the Class are converted, automatically or by action of the holders thereof, into common stock pursuant to the provisions of the Company’s Certificate of Incorporation, including, without limitation, in connection with the Company’s initial, underwritten public offering and sale of its common stock pursuant to an effective registration statement under the Act (the “IPO”) then from and after the date on which all outstanding shares of the Class have been so converted, this Warrant shall be exercisable for such number of shares of common stock into which the Shares would have been converted had the Shares been outstanding on the date of such conversion, and the Warrant Price shall equal the Warrant Price in effect as of immediately prior to such conversion divided by the number of shares of common stock into which one Share would have been converted, all subject to further adjustment thereafter from time to time in accordance with the provisions of this Warrant.

2.4    Adjustments for Diluting Issuances. Without duplication of any adjustment otherwise provided for in this Section 2, the number of shares of common stock issuable upon conversion of the Shares shall be subject to anti-dilution adjustment from time to time in the manner set forth in the Company’s Certificate of Incorporation as if the Shares were issued and outstanding on and as of the date of any such required adjustment.

2.5    No Fractional Share. No fractional Share shall be issuable upon exercise of this Warrant and the number of Shares to be issued shall be rounded down to the nearest whole Share. If a fractional Share interest arises upon any exercise of the Warrant, the Company shall eliminate such fractional Share interest by paying Holder in cash the amount computed by multiplying the fractional interest by (i) the fair market value (as determined in accordance with Section 1.3 above) of a full Share, less (ii) the then-effective Warrant Price.

2.6    Notice/Certificate as to Adjustments. Upon each adjustment of the Warrant Price, Class and/or number of Shares, the Company, at the Company’s expense, shall notify Holder in writing within a reasonable time setting forth the adjustments to the Warrant Price, Class and/or number of Shares and facts upon which such adjustment is based. The Company shall, upon written request from Holder, furnish Holder with a certificate of its Chief Financial Officer, including computations of such adjustment and the Warrant Price, Class and number of Shares in effect upon the date of such adjustment.

SECTION 3. REPRESENTATIONS AND COVENANTS OF THE COMPANY.

3.1    Representations and Warranties. The Company represents and warrants to, and agrees with, the Holder as follows:

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(a)    The initial Warrant Price referenced on the first page of this Warrant is not greater than the price per share at which shares of the Class were last sold and issued prior to the Issue Date hereof in an arms-length transaction in which at least $500,000 of such shares were sold.

(b)    All Shares which may be issued upon the exercise of this Warrant, and all securities, if any, issuable upon conversion of the Shares, shall, upon issuance in accordance with the terms of this Warrant (and, in the case of any such conversion securities, the terms of the Company’s Certificate of Incorporation), be duly authorized, validly issued, fully paid and non-assessable, and free of any liens and encumbrances except for restrictions on transfer provided for herein, under applicable federal and state securities laws or under the Voting Agreement (to the extent Holder is then a party thereto or is required by the terms of Section 1.7 above to become a party). The Company covenants that it shall at all times cause to be reserved and kept available out of its authorized and unissued capital stock such number of shares of the Class, common stock and other securities as will be sufficient to permit the exercise in full of this Warrant and the conversion of the Shares into common stock or such other securities.

(c)    The Company’s capitalization table attached hereto as Schedule 1 is true and complete, in all material respects, as of the Issue Date.

3.2    Notice of Certain Events. If the Company proposes at any time to:

(a)    declare any dividend or distribution upon the outstanding shares of the Class or common stock, whether in cash, property, stock, or other securities and whether or not a regular cash dividend;

(b)    offer for subscription or sale pro rata to the holders of the outstanding shares of the Class any additional shares of any class or series of the Company’s stock (other than pursuant to contractual pre-emptive rights);

(c)    effect any reclassification, exchange, combination, substitution, reorganization or recapitalization of the outstanding shares of the Class;

(d)    effect an Acquisition or to liquidate, dissolve or wind up; or

(e)    effect an IPO;

then, in connection with each such event, the Company shall give Holder:

(1)    in the case of the matters referred to in (a) and (b) above, at least seven (7) Business Days prior written notice of the earlier to occur of the effective date thereof or the date on which a record will be taken for such dividend, distribution, or subscription rights (and specifying the date on which the holders of outstanding shares of the Class will be entitled thereto) or for determining rights to vote, if any;

(2)    in the case of the matters referred to in (c) and (d) above at least seven (7) Business Days prior written notice of the date when the same will take

6

place (and specifying the date on which the holders of outstanding shares of the Class will be entitled to exchange their shares for the securities or other property deliverable upon the occurrence of such event and such reasonable information as Holder may reasonably require regarding the treatment of this Warrant in connection with such event giving rise to the notice); and

(3)    with respect to the IPO, at least seven (7) Business Days prior written notice of the date on which the Company proposes to file its registration statement in connection therewith.

The Company will also provide information requested by Holder that is reasonably necessary to enable Holder to comply with Holder’s accounting or reporting requirements.

SECTION 4. REPRESENTATIONS AND WARRANTIES OF THE HOLDER.

The Holder represents and warrants to the Company as follows:

4.1    Purchase for Own Account. This Warrant and the securities to be acquired upon exercise of this Warrant by Holder are being acquired for investment for Holder’s account, not as a nominee or agent, and not with a view to the public resale or distribution within the meaning of the Act. Holder also represents that it has not been formed for the specific purpose of acquiring this Warrant or the Shares.

4.2    Disclosure of Information. Holder is aware of the Company’s business affairs and financial condition and has received or has had full access to all the information it considers necessary or appropriate to make an informed investment decision with respect to the acquisition of this Warrant and its underlying securities. Holder further has had an opportunity to ask questions and receive answers from the Company regarding the terms and conditions of the offering of this Warrant and its underlying securities and to obtain additional information (to the extent the Company possessed such information or could acquire it without unreasonable effort or expense) necessary to verify any information furnished to Holder or to which Holder has access.

4.3    Investment Experience. Holder understands that the purchase of this Warrant and its underlying securities involves substantial risk. Holder has experience as an investor in securities of companies in the development stage and acknowledges that Holder can bear the economic risk of such Holder’s investment in this Warrant and its underlying securities and has such knowledge and experience in financial or business matters that Holder is capable of evaluating the merits and risks of its investment in this Warrant and its underlying securities and/or has a preexisting personal or business relationship with the Company and certain of its officers, directors or controlling persons of a nature and duration that enables Holder to be aware of the character, business acumen and financial circumstances of such persons.

4.4    Accredited Investor Status. Holder is an “accredited investor” within the meaning of Regulation D promulgated under the Act.

4.5    The Act. Holder understands that this Warrant and the Shares issuable upon exercise hereof have not been registered under the Act in reliance upon a specific exemption therefrom, which exemption depends upon, among other things, the bona fide nature of the

7

Holder’s investment intent as expressed herein. Holder understands that this Warrant and the Shares issued upon any exercise hereof must be held indefinitely unless subsequently registered under the Act and qualified under applicable state securities laws, or unless exemption from such registration and qualification are otherwise available. Holder is aware of the provisions of Rule 144 promulgated under the Act.

4.6    Market Stand-off Agreement. The Holder agrees that the Shares shall be subject to the Market Standoff provisions in Section 2.11 of the Company’s Investor Rights Agreement, as amended and in effect from time to time.

4.7    No Voting Rights. Holder, as a Holder of this Warrant, will not have any voting rights until the exercise of this Warrant.

SECTION 5. MISCELLANEOUS.

5.1    Term; Automatic Cashless Exercise Upon Expiration.

(a)    Term. Subject to the provisions of Section 1.6 above, this Warrant is exercisable in whole or in part at any time and from time to time on or before 6:00 PM, Pacific time, on the Expiration Date and shall be void thereafter.

(b)    Automatic Cashless Exercise upon Expiration. In the event that, upon the Expiration Date, the fair market value of one Share (or other security issuable upon the exercise hereof) as determined in accordance with Section 1.3 above is greater than the Warrant Price in effect on such date, then this Warrant shall automatically be deemed on and as of such date to be exercised pursuant to Section 1.2 above as to all Shares (or such other securities) for which it shall not previously have been exercised, and the Company shall, within a reasonable time, deliver a certificate representing the Shares (or such other securities) issued upon such exercise to Holder.

5.2    Legends. Each certificate evidencing Shares (and each certificate evidencing securities issued upon conversion of any Shares, if any) shall be imprinted with a legend in substantially the following form:

THE SHARES EVIDENCED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “ACT”) OR THE SECURITIES LAWS OF ANY STATE AND, EXCEPT AS SET FORTH IN THAT CERTAIN WARRANT TO PURCHASE STOCK ISSUED BY THE ISSUER TO [SILICON VALLEY BANK / LIFE SCIENCE LOANS, LLC] DATED OCTOBER 25, 2016, MAY NOT BE OFFERED, SOLD, PLEDGED OR OTHERWISE TRANSFERRED UNLESS AND UNTIL REGISTERED UNDER SAID ACT AND LAWS OR, IN THE OPINION OF LEGAL COUNSEL IN FORM AND SUBSTANCE SATISFACTORY TO THE ISSUER, SUCH OFFER, SALE, PLEDGE OR OTHER TRANSFER IS EXEMPT FROM SUCH REGISTRATION.

5.3    Compliance with Securities Laws on Transfer. This Warrant and the Shares issued upon exercise of this Warrant (and the securities issuable, directly or indirectly, upon conversion of the Shares, if any) may not be transferred or assigned in whole or in part except in compliance

8

with applicable federal and state securities laws by the transferor and the transferee (including, without limitation, the delivery of investment representation letters and legal opinions reasonably satisfactory to the Company, as reasonably requested by the Company). The Company shall not require Holder to provide an opinion of counsel if the transfer is to [SVB Financial Group (Silicon Valley Bank’s parent company) or any other] [an] affiliate of Holder, provided that [any] such [transferee / affiliate] is an “accredited investor” as defined in Regulation D promulgated under the Act. Additionally, the Company shall also not require an opinion of counsel if there is no material question as to the availability of Rule 144 promulgated under the Act.

5.4    Transfer Procedure. [After receipt by Silicon Valley Bank of the executed Warrant, Silicon Valley Bank will transfer all of this Warrant to its parent company, SVB Financial Group. By its acceptance of this Warrant, SVB Financial Group hereby makes to the Company each of the representations and warranties set forth in Section 4 hereof and agrees to be bound by all of the terms and conditions of this Warrant as if the original Holder hereof.] Subject to the provisions of Section 5.3 and upon providing the Company with written notice, [SVB Financial Group and any subsequent] Holder may transfer all or part of this Warrant or the Shares issued upon exercise of this Warrant (or the securities issued upon conversion of the Shares, if any) to any transferee, provided, however, in connection with any such transfer, [SVB Financial Group or any subsequent] Holder will give the Company notice of the portion of the Warrant and/or Shares (and/or securities issued upon conversion of the Shares, if any) being transferred with the name, address and taxpayer identification number of the transferee and Holder will surrender this Warrant to the Company for reissuance to the transferee(s) (and Holder if applicable); and provided further, that any subsequent transferee [other than SVB Financial Group] shall agree in writing with the Company to be bound by all of the terms and conditions of this Warrant. Notwithstanding any contrary provision herein, at all times prior to the IPO, Holder may not, without the Company’s prior written consent, transfer this Warrant or any portion hereof, or any Shares issued upon any exercise hereof, or any shares or other securities issued upon any conversion of any Shares issued upon any exercise hereof, to any person or entity who directly competes with the Company, except in connection with an Acquisition of the Company by such a direct competitor.

5.5    Notices. All notices and other communications hereunder from the Company to the Holder, or vice versa, shall be deemed delivered and effective (i) when given personally, (ii) on the third (3^rd) Business Day after being mailed by first-class registered or certified mail, postage prepaid, (iii) upon actual receipt if given by facsimile or electronic mail and such receipt is confirmed in writing by the recipient, or (iv) on the first Business Day following delivery to a reliable overnight courier service, courier fee prepaid, in any case at such address as may have been furnished to the Company or Holder, as the case may be, in writing by the Company or such Holder from time to time in accordance with the provisions of this Section 5.5. All notices to Holder shall be addressed as follows until the Company receives notice of a change of address in connection with a transfer or otherwise:

[___]

Attn: [___]

[___]

[___]

Telephone: [___]

Facsimile: [___]

9

Email address: [___]

Notice to the Company shall be addressed as follows until Holder receives notice of a change in address:

X4 Pharmaceuticals, Inc.

Attn: Chief Financial Officer

784 Memorial Drive, Suite 140

Cambridge, MA 02139

Telephone:

Facsimile:

Email:

With a copy (which shall not constitute notice) to:

Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C.

Attn: Meryl J. Epstein, Esq.

One Financial Center, Boston, MA 02111

Telephone: (617) 348-1635

Facsimile: (617) 542-2241

Email: mjepstein@mintz.com

5.6    Waiver. This Warrant and any term hereof may be changed, waived, discharged or terminated (either generally or in a particular instance and either retroactively or prospectively) only by an instrument in writing signed by the party against which enforcement of such change, waiver, discharge or termination is sought.

5.7    Attorneys’ Fees. In the event of any dispute between the parties concerning the terms and provisions of this Warrant, the party prevailing in such dispute shall be entitled to collect from the other party all costs incurred in such dispute, including reasonable attorneys’ fees.

5.8    Counterparts; Facsimile/Electronic Signatures. This Warrant may be executed in counterparts, all of which together shall constitute one and the same agreement. Any signature page delivered electronically or by facsimile shall be binding to the same extent as an original signature page with regards to any agreement subject to the terms hereof or any amendment thereto.

5.9    Governing Law. This Warrant shall be governed by and construed in accordance with the laws of the State of California, without giving effect to its principles regarding conflicts of law.

5.10    Headings. The headings in this Warrant are for purposes of reference only and shall not limit or otherwise affect the meaning of any provision of this Warrant.

5.11    Business Days. “Business Day” is any day that is not a Saturday, Sunday or a day on which [Silicon Valley Bank is] [banks in Washington are] closed.

[Remainder of page left blank intentionally]

10

[Signature page follows]

11

IN WITNESS WHEREOF, the parties have caused this Warrant to Purchase Stock to be executed by their duly authorized representatives effective as of the Issue Date written above.

APPENDIX 1

NOTICE OF EXERCISE

1.    The undersigned Holder hereby exercises its right to purchase _____________ shares of the Common/Series _______ Preferred [circle one] Stock of ____________________ (the “Company”) in accordance with the attached Warrant To Purchase Stock, and tenders payment of the aggregate Warrant Price for such shares as follows:

2.    Please issue a certificate or certificates representing the Shares in the name specified below:

Holder’s Name

(Address)

3.    By its execution below and for the benefit of the Company, Holder hereby restates each of the representations and warranties in Section 4 of the Warrant to Purchase Stock as of the date hereof.

Appendix 1

Exhibit 4.3

Form of Maxim Warrant

THIS WARRANT AND THE UNDERLYING SECURITIES ISSUABLE UPON THE EXERCISE THEREOF HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “ACT”). NO SALE OR DISPOSITION MAY BE EFFECTED EXCEPT IN COMPLIANCE WITH RULE 144 UNDER SAID ACT OR AN EFFECTIVE REGISTRATION STATEMENT RELATED THERETO OR AN OPINION OF COUNSEL FOR THE HOLDER SATISFACTORY TO THE COMPANY THAT SUCH REGISTRATION IS NOT REQUIRED UNDER THE ACT.

X4 PHARMACEUTICALS, INC.

WARRANT TO PURCHASE PREFERRED STOCK

VOID AFTER                     , 2020

THIS CERTIFIES THAT, for value received, Maxim Partners, LLC, with its principal office at 405 Lexington Ave., New York, NY 10174, or assigns (the “Holder”), is entitled to subscribe for and purchase from X4 PHARMACEUTICALS, INC, a Delaware corporation, with its principal office at 784 Memorial Drive, Suite #140, Cambridge, MA 02139 (the “Company”), the Exercise Shares at the Exercise Price (each subject to adjustment as provided herein). Unless indicated otherwise, the aggregate number of Exercise Shares that Holder may purchase by exercising this Warrant is equal to [        ] Exercise Shares, subject to adjustment pursuant to the terms hereof, including but not limited to adjustments pursuant to Sections 5 and 7 below.

1. DEFINITIONS. Capitalized terms used but not defined herein shall have the meanings set forth in the Agreement. As used herein, the following terms shall have the following respective meanings:

(a) “Equity Securities” shall mean shares of the Company’s shares of Series A Preferred Stock, par value U.S. $0.001 per share.

(b) “Exercise Period” shall mean the period commencing on the date hereof and ending five (5) years later, unless sooner terminated as provided below

(c) “Exercise Price” shall mean $2.07; provided, that, the Exercise Price shall be subject to adjustment pursuant to Sections 5 and 7 below.

(d) “Exercise Shares” shall mean the Equity Securities issuable upon exercise of this Warrant and any Conversion Securities (as defined below).

2. EXERCISE OF WARRANT. The rights represented by this Warrant may be exercised in whole or in part at any time during the Exercise Period, by delivery of the following to the Company at its address set forth above (or at such other address as it may designate by notice in writing to the Holder):

1.

(a) an executed Notice of Exercise in the form attached hereto;

(b) payment of the Exercise Price either (i) in cash or by check, (ii) by wire transfer or (iii) pursuant to Section 2.1 below; and

(c) this Warrant.

Upon the exercise of the rights represented by this Warrant, a certificate or certificates for the Exercise Shares so purchased, registered in the name of the Holder shall be issued and delivered to the Holder within a reasonable time after the rights represented by this Warrant shall have been so exercised. In the event that this Warrant is being exercised for less than all of the then-current number of Exercise Shares purchasable hereunder, the Company shall, concurrently with the issuance by the Company of the number of Exercise Shares for which this Warrant is then being exercised, issue a new Warrant exercisable for the remaining number of Exercise Shares purchasable hereunder.

The person in whose name any certificate or certificates for Exercise Shares are to be issued upon exercise of this Warrant shall be deemed to have become the holder of record of such shares on the date on which this Warrant was surrendered and payment of the Exercise Price was made, irrespective of the date of delivery of such certificate or certificates, except that, if the date of such surrender and payment is a date when the stock transfer books of the Company are closed, such person shall be deemed to have become the holder of such shares at the close of business on the next succeeding date on which the stock transfer books are open.

2.1 Net Exercise. Notwithstanding any provisions herein to the contrary, if the fair market value of one Exercise Share is greater than the Exercise Price (at the date of calculation as set forth below), in lieu of exercising this Warrant by payment of cash, the Holder may elect to receive shares equal to the value (as determined below) of this Warrant (or the portion thereof being canceled) by surrender of this Warrant at the principal office of the Company together with the properly endorsed Notice of Exercise in which event the Company shall issue to the Holder a number of Exercise Shares computed using the following formula:

X = Y (A-B)

    A

Where X = the number of Exercise Shares to be issued to the Holder

For purposes of the above calculation, the fair market value of one Exercise Share shall be determined by the Company’s Board of Directors in good faith; provided, however, that in the event that this Warrant is exercised pursuant to this Section 2.1 in connection with the Company’s initial public offering of its Common Stock, the fair market value per share shall be the product of (i) the per share offering price to the public of the Company’s initial public offering, and (ii) the number of shares of Common Stock into which each Exercise Share is convertible at the time of such exercise.

2.

3. COVENANTS OF THE COMPANY.

3.1 Covenants as to Exercise Shares. Except as provided in the last sentence of this Section 3.1, the Company covenants and agrees that all Exercise Shares that may be issued upon the exercise of the rights represented by this Warrant will, upon issuance, be validly issued and outstanding, fully paid and nonassessable, and free from all taxes, liens and charges with respect to the issuance thereof. The Company further covenants and agrees that the Company will at all times during the Exercise Period, have authorized and reserved, free from preemptive rights, a sufficient number of shares of the series of equity securities comprising the Exercise Shares to provide for the exercise of the rights represented by this Warrant. If at any time during the Exercise Period the number of authorized but unissued shares of such series of the Company’s equity securities shall not be sufficient to permit exercise of this Warrant, the Company will take such corporate action as may, in the opinion of its counsel, be necessary to increase its authorized but unissued shares of such series of the Company’s equity securities to such number of shares as shall be sufficient for such purposes.

3.2 Notices of Record Date. In the event of any taking by the Company of a record of the holders of any class of securities for the purpose of determining the holders thereof who are entitled to receive any dividend or other distribution, the Company shall mail to the Holder, at least ten (10) days prior to the date specified herein, a notice specifying the date on which any such record is to be taken for the purpose of such dividend or distribution.

4. REPRESENTATIONS OF HOLDER.

4.1 Acquisition of Warrant for Personal Account. The Holder represents and warrants that it is acquiring the Warrant and the Exercise Shares solely for its account for investment and not with a view to or for sale or distribution of said Warrant or Exercise Shares or any part thereof. The Holder also represents that the entire legal and beneficial interests of the Warrant and Exercise Shares the Holder is acquiring is being acquired for, and will be held for, its account only.

4.2 Securities Are Not Registered.

(a) The Holder understands that the Warrant and the Exercise Shares have not been registered under the Securities Act of 1933, as amended (the “Act”) on the basis that no distribution or public offering of the stock of the Company is to be effected. The Holder realizes that the basis for the exemption may not be present if, notwithstanding its representations, the Holder has a present intention of acquiring the securities for a fixed or determinable period in the future, selling (in connection with a distribution or otherwise), granting any participation in, or otherwise distributing the securities. The Holder has no such present intention.

3.

(b) The Holder recognizes that the Warrant and the Exercise Shares must be held indefinitely unless they are subsequently registered under the Act or an exemption from such registration is available. The Holder recognizes that the Company has no obligation to register the Warrant or the Exercise Shares of the Company, or to comply with any exemption from such registration.

(c) The Holder is aware that neither the Warrant nor the Exercise Shares may be sold pursuant to Rule 144 adopted under the Act unless certain conditions are met, including, among other things, the existence of a public market for the shares, the availability of certain current public information about the Company, the resale following the required holding period under Rule 144 and the number of shares being sold during any three month period not exceeding specified limitations. Holder is aware that the conditions for resale set forth in Rule 144 have not been satisfied and that the Company presently has no plans to satisfy these conditions in the foreseeable future.

4.3 Disposition of Warrant and Exercise Shares.

(a) The Holder further agrees not to make any disposition of all or any part of the Warrant or Exercise Shares in any event unless and until:

(i) the Company shall have received a letter secured by the Holder from the Securities and Exchange Commission stating that no action will be recommended to the Commission with respect to the proposed disposition;

(ii) there is then in effect a registration statement under the Act covering such proposed disposition and such disposition is made in accordance with said registration statement; or

(iii) the Holder shall have notified the Company of the proposed disposition and shall have furnished the Company with a detailed statement of the circumstances surrounding the proposed disposition, and if reasonably requested by the Company, the Holder shall have furnished the Company with an opinion of counsel, reasonably satisfactory to the Company, for the Holder to the effect that such disposition will not require registration of such Warrant or Exercise Shares under the Act or any applicable state securities laws.

(b) The Holder understands and agrees that all certificates evidencing the shares to be issued to the Holder may bear the following legend:

THESE SECURITIES HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “ACT”). THEY MAY NOT BE SOLD, OFFERED FOR SALE, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT AS TO THE SECURITIES UNDER THE ACT OR AN OPINION OF COUNSEL SATISFACTORY TO THE COMPANY THAT SUCH REGISTRATION IS NOT REQUIRED.

4.4 Accredited Investor Status. The Holder is an “accredited investor” as defined in Regulation D promulgated under the Act.

4.

5. ADJUSTMENT OF EXERCISE PRICE AND NUMBER OF EXERCISE SHARES.

5.1 Changes in Securities. In the event of changes in the series of equity securities of the Company comprising the Exercise Shares by reason of stock dividends, splits, recapitalizations, reclassifications, combinations or exchanges of shares, separations, reorganizations, liquidations, or the like, the number and class of Exercise Shares available under the Warrant in the aggregate and the Exercise Price shall be correspondingly adjusted to give the Holder of the Warrant, on exercise for the same aggregate Exercise Price, the total number, class, and kind of shares as the Holder would have owned had the Warrant been exercised prior to the event and had the Holder continued to hold such shares until after the event requiring adjustment. For purposes of this Section 5 and Section 7, the “Aggregate Exercise Price” shall mean the aggregate Exercise Price payable in connection with the exercise in full of this Warrant. The form of this Warrant need not be changed because of any adjustment in the number of Exercise Shares subject to this Warrant.

5.2 Conversion. Upon the conversion of all outstanding shares of the series of equity securities comprising the Exercise Shares, this Warrant shall become exercisable for that class, series, kind, and number of shares of equity securities (the “Conversion Securities”) into which the Exercise Shares would then be convertible and the Exercise Price shall be correspondingly adjusted to give the Holder of the Warrant, on exercise for the same aggregate Exercise Price, the total number, class, series, and kind of shares as the Holder would have owned if this Warrant had been exercised prior to such event and such Exercise Shares had been acquired. In such case, all references to “Exercise Shares” shall mean the Conversion Securities. Conversion Securities shall be subject to further and successive adjustments pursuant to this Section 5.

6. FRACTIONAL SHARES. No fractional shares shall be issued upon the exercise of this Warrant as a consequence of any adjustment pursuant hereto. All Exercise Shares (including fractions) to be issued upon exercise of this Warrant shall be aggregated for purposes of determining whether the exercise would result in the issuance of any fractional share. If, after aggregation, the exercise would result in the issuance of a fractional share, the Company shall, in lieu of issuance of any fractional share, pay the Holder otherwise entitled to such fraction a sum in cash equal to the product resulting from multiplying the then current fair market value of one Exercise Share by such fraction.

7. EARLY TERMINATION. In the event of, at any time during the Exercise Period, an initial public offering of securities of the Company registered under the Act, or a [Deemed Liquidation Event] (as defined in the Company’s Certificate of Incorporation), the Company shall provide to the Holder ten (10) days advance written notice of the estimated closing date of such public offering or Deemed Liquidation Event, and, unless the Holder exercises this Warrant pursuant to the terms of Section 2 within five (5) days of the receipt of such advance written notice, this Warrant shall be deemed exercised pursuant to Section 2.1 immediately prior to the date such public offering is closed or the closing of such Deemed Liquidation Event.

5.

8. MARKET STAND-OFF AGREEMENT. The Holder hereby agrees that it will not, without the prior written consent of the managing underwriter, during the period beginning on and including the date that the Company’s Common Stock is first quoted on a national exchange and continuing through the close of trading on the date that is 180 days thereafter , or such other period as may be requested by the Company or an underwriter to comply with regulatory restrictions on (1) the publication or other distribution of research reports and (2) analyst recommendations and options, including, but not limited to, the restrictions contained in FINRA Rule 2711(f)(4) or NYSE Rule 472(f)(4), or any successor provisions or amendments thereto), (i) lend; offer; pledge; sell; contract to sell; sell any option or contract to purchase; purchase any option or contract to sell; grant any option, right, or warrant to purchase; or otherwise transfer or dispose of, directly or indirectly, any shares of Common Stock or any securities convertible into or exercisable or exchangeable (directly or indirectly) for Common Stock (whether such shares or any such securities are then owned by the Holder or are thereafter acquired) or (ii) enter into any swap or other arrangement that transfers to another, in whole or in part, any of the economic consequences of ownership of such securities, whether any such transaction described in clause (i) or (ii) above is to be settled by delivery of Common Stock or other securities, in cash, or otherwise. The foregoing provisions of this Section shall apply only to an initial public offering, shall not apply to the sale of any shares to an underwriter pursuant to an underwriting agreement, or the transfer of any shares to any trust for the direct or indirect benefit of the Holder or the immediate family of the Holder, provided that the trustee of the trust agrees to be bound in writing by the restrictions set forth herein, and provided further that any such transfer shall not involve a disposition for value (an “Estate Planning Transfer”), and shall be applicable to the Holder only if all officers and directors are subject to the same restrictions and the Company uses commercially reasonable efforts to obtain a similar agreement from all stockholders individually owning more than one percent (1%) of the Company’s outstanding Common Stock (after giving effect to conversion into Common Stock of all outstanding Preferred Stock). The underwriters in connection with such registration are intended third-party beneficiaries of this Section and shall have the right, power, and authority to enforce the provisions hereof as though they were a party hereto. Each Holder further agrees to execute such agreements as may be reasonably requested by the underwriters in connection with such registration that are consistent with this Section or that are necessary to give further effect thereto. Any discretionary waiver or termination of the restrictions of any or all of such agreements by the Company or the underwriters shall apply pro rata to all Holders subject to such agreements, based on the number of shares subject to such agreements. Holder agrees that any transferee of the Warrant (or other securities) of the Company held by Holder shall be bound by this Section 8.

9. Rights and Restrictions of the Holder. As contemplated by that certain Series A Preferred Stock Purchase Agreement by and among the Company and the purchasers named therein dated as of August 14, 2015 (the “Purchase Agreement”), the Equity Securities shall be deemed to have been issued under the Purchase Agreement and accordingly the Equity Securities and the Exercise Shares issuable upon the conversion of such Equity Securities shall be entitled to the rights, benefits and restrictions accorded to the Equity Securities, and the Equity Shares issuable upon conversion thereof, issued pursuant to the Purchase Agreement, including the rights, benefits and restrictions set forth in the Purchase Agreement and the related Investor Rights Agreement, in each case as amended, and the applicable provisions of the Company’s Amended and Restated Certificate of Incorporation, the Purchase Agreement and the related Investor Rights Agreement and Right of First Refusal and Co-Sale Agreement are hereby incorporated herein by reference and made a part hereof as if set forth herein in their entirety.

6.

10. NO STOCKHOLDER RIGHTS. This Warrant in and of itself shall not entitle the Holder to any voting rights or other rights as a stockholder of the Company.

11. TRANSFER OF WARRANT. Without the prior written consent of the Company, this Warrant shall not be assigned, pledged or hypothecated in any way (whether by operation of law or otherwise) and shall not be subject to execution, attachment or similar process, provided, however, that the Holder may assign this Warrant to its affiliate(s) without such prior written consent of the Company. Any attempted transfer, assignment, pledge, hypothecation or other disposition of this Warrant or of any rights granted hereunder contrary to the provisions of this Section 11, or the levy of any attachment or similar process upon this Warrant or such rights, shall be null and void.

12. LOST, STOLEN, MUTILATED OR DESTROYED WARRANT. If this Warrant is lost, stolen, mutilated or destroyed, the Company may, on such terms as to indemnity or otherwise as it may reasonably impose (which shall, in the case of a mutilated Warrant, include the surrender thereof), issue a new Warrant of like denomination and tenor as the Warrant so lost, stolen, mutilated or destroyed. Any such new Warrant shall constitute an original contractual obligation of the Company, whether or not the allegedly lost, stolen, mutilated or destroyed Warrant shall be at any time enforceable by anyone.

13. AMENDMENT. Any term of this Warrant may be amended or waived with the written consent of the Company and Holders of at least a majority in interest of the outstanding Warrants provided that all Warrants are similarly affected. Upon the effectuation of such amendment or waiver in conformance with this Section 13, the Company shall promptly give written notice thereof to the record holders of the Warrants who have not previously consented thereto in writing.

14. NOTICES, ETC. All notices required or permitted hereunder shall be in writing and shall be deemed effectively given: (a) upon personal delivery to the party to be notified, (b) when sent by confirmed telex or facsimile if sent during normal business hours of the recipient, if not, then on the next business day, (c) five (5) days after having been sent by registered or certified mail, return receipt requested, postage prepaid, or (d) one (1) day after deposit with a nationally recognized overnight courier, specifying next day delivery, with written verification of receipt. All communications shall be sent to the Company at the address listed on the signature page and to the Holder at 405 Lexington Ave., New York, NY 10174, or at such other address as the Company or Holder may designate by ten (10) days advance written notice to the other parties hereto.

15. ACCEPTANCE. Receipt of this Warrant by the Holder shall constitute acceptance of and agreement to all of the terms and conditions contained herein.

16. GOVERNING LAW. This Warrant and all rights, obligations and liabilities hereunder shall be governed by and construed under the laws of the Commonwealth of Massachusetts as applied to agreements among Massachusetts residents, made and to be performed entirely within the Commonwealth of Massachusetts without giving effect to conflicts of laws principles.

7.

IN WITNESS WHEREOF, the Company has caused this Warrant to be executed by its duly authorized officer as of [●], 2015.

SIGNATURE PAGE TO WARRANT TO PURCHASE PREFERRED STOCK

NOTICE OF EXERCISE

TO: X4 PHARMACEUTICALS, INC

(1) ☐ The undersigned hereby elects to purchase ________ shares of ___________ (the “Exercise Shares”) of X4 PHARMACEUTICALS, INC. (the “Company”) pursuant to the terms of the attached Warrant, and tenders herewith payment of the exercise price in full, together with all applicable transfer taxes, if any.

☐ The undersigned hereby elects to purchase ________ shares of __________ (the “Exercise Shares”) of X4 PHARMACEUTICALS, INC (the “Company”) pursuant to the terms of the net exercise provisions set forth in Section 2.1 of the attached Warrant, and shall tender payment of all applicable transfer taxes, if any.

(2) Please issue a certificate or certificates representing said Exercise Shares in the name of the undersigned or in such other name as is specified below:

(Name)

(Address)

(3) The undersigned represents that (i) the aforesaid Exercise Shares are being acquired for the account of the undersigned for investment and not with a view to, or for resale in connection with, the distribution thereof and that the undersigned has no present intention of distributing or reselling such shares; (ii) the undersigned is aware of the Company’s business affairs and financial condition and has acquired sufficient information about the Company to reach an informed and knowledgeable decision regarding its investment in the Company; (iii) the undersigned is experienced in making investments of this type and has such knowledge and background in financial and business matters that the undersigned is capable of evaluating the merits and risks of this investment and protecting the undersigned’s own interests; (iv) the undersigned understands that Exercise Shares issuable upon exercise of this Warrant have not been registered under the Securities Act of 1933, as amended (the “Securities Act”), by reason of a specific exemption from the registration provisions of the Securities Act, which exemption depends upon, among other things, the bona fide nature of the investment intent as expressed herein, and, because such securities have not been registered under the Securities Act, they must be held indefinitely unless subsequently registered under the Securities Act or an exemption from such registration is available; (v) the undersigned is aware that the aforesaid Exercise Shares may not be sold pursuant to Rule 144 adopted under the Securities Act unless certain conditions are met and until the undersigned has held the shares for the number of years prescribed by Rule 144, that among the conditions for use of the Rule is the availability of current information to the public about the Company and the Company has not made such information available and has no present plans to do so; and (vi) the undersigned agrees not to make any disposition of all or any part of the aforesaid shares of Exercise Shares unless and until there is then in effect a registration statement under the Securities Act covering such proposed disposition and such disposition is made in accordance with said registration statement, or, if reasonably requested by the Company, the undersigned has provided the Company with an opinion of counsel satisfactory to the Company, stating that such registration is not required.

A-1

(4) By execution and delivery of this notice, the undersigned hereby agrees to become a party to (i) that certain Amended and Restated Investors’ Rights Agreement dated as of August 14, 2015 (the “Investors’ Rights Agreement”) by and among the Company and the Investors (as defined in the Investors’ Rights Agreement), (ii) that certain Amended and Restated Voting Agreement dated as of August 14, 2015 (the “Voting Agreement”) by and among the Company and the Investors (as defined in the Voting Agreement) and (iii) that certain Amended and Restated Right of First Refusal and Co-Sale Agreement, dated as of August 14, 2015 (the “ROFR Agreement”) by and among the Company and the Investors and Key Holders (as defined in the ROFR Agreement) and the undersigned is entitled to all of the benefits under and subject to all of the obligations, restrictions and limitations set forth in the Investors’ Rights Agreement, Voting Agreement and ROFR Agreement that are applicable to the Investors. This notice shall take effect and shall become a part of said Investors’ Rights Agreement, Voting Agreement and ROFR Agreement immediately upon execution.

2.

Exhibit 4.4

THIS WARRANT AND THE SECURITIES ISSUABLE UPON THE EXERCISE HEREOF HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED. THEY MAY NOT BE SOLD, OFFERED FOR SALE, PLEDGED, HYPOTHECATED, OR OTHERWISE TRANSFERRED EXCEPT PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933, AS AMENDED OR AN OPINION OF COUNSEL SATISFACTORY TO THE COMPANY THAT REGISTRATION IS NOT REQUIRED.

X4 PHARMACEUTICALS, INC.

WARRANT TO PURCHASE SERIES B PREFERRED STOCK

Void after                     , 2020

THIS WARRANT TO PURCHASE SERIES B PREFERRED STOCK (this “Warrant”) is issued to [_________] (the “Holder”) by X4 Pharmaceuticals, Inc. (the “Company”), as of November 1, 2017 pursuant to the terms of the Series B Preferred Stock Purchase Agreement, dated November 1, 2017 by and among the Company and the Investors therewith (the “Purchase Agreement”).

1. Purchase of Exercise Shares. Subject to the terms and conditions hereinafter set forth, the Holder is entitled, upon surrender of this Warrant at the principal office of the Company (or at such other place as the Company shall notify the holder hereof in writing), to purchase from the Company the Exercise Shares at the Exercise Price (each subject to adjustment as provided herein) at any time or from time to time at or before the earlier of 5:00 p.m. eastern time on the Expiration Date (as defined below). This Warrant shall be exercisable, in whole or in part, prior to the Expiration Date.

2. Definitions.

(a) “Conversion Shares” shall mean the shares of Common Stock issuable upon conversion of the Exercise Shares.

(b) “Exercise Price” shall mean $1.88 per Exercise Share, subject to adjustment pursuant to Section 7 below.

(c) “Exercise Shares” shall mean [_______] shares¹ of the Company’s Series B Preferred Stock issuable upon exercise of this Warrant, subject to adjustment pursuant to Section 7 below. The Exercise Shares shall have the rights and preferences associated with them as set forth in the Restated Certificate.

(d) “Expiration Date” shall mean November 1, 2020.

(e) “Majority of the Conversion Shares” shall mean a majority of the Conversion Shares issuable upon exercise and conversion of all the Warrants issued pursuant to the Purchase Agreement.

(f) “Series B Preferred Stock” shall mean the Company’s Series B Preferred Stock, par value $0.001 per share.

(g) “Shares” shall mean the Exercise Shares and Conversion Shares.

(h) “Restated Certificate” shall mean the Third Amended and Restated Certificate of Incorporation of the Company, as amended and/or amended and restated from time to time.

3. Exercise of Warrant. While this Warrant remains outstanding and exercisable, the Holder may exercise, in whole or in part, the purchase rights evidenced hereby. Such exercise shall be effected by: (a) the surrender of the Warrant, together with a notice of exercise to the Secretary of the Company at its principal offices; and (b) the payment to the Company of an amount equal to the aggregate Exercise Price for the number of Exercise Shares being purchased. Payment of the purchase price shall be in cash or by certified or official bank check payable to the order of the Company

4. Net Exercise. Notwithstanding any provisions herein to the contrary, in lieu of exercising this Warrant by delivering payment of the purchase price to the Company as provided in Section 3(b), the Holder may elect to receive shares equal to the value of this Warrant (or the portion thereof being canceled) by surrender of this Warrant at the principal office of the Company together with notice of such election at any time or from time to time prior to the Expiration Date, in which event the Company shall issue to the holder hereof a number of Exercise Shares computed using the following formula:

        Y (A - B)

X =             A

Where

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For purposes of the above calculation, the fair market value of one Exercise Share as of a particular date (the “Determination Date”) shall mean:

(A) In the event that all of the Company’s shares of Preferred Stock shall prior to exercise or exchange of this Warrant have been converted into shares of the Common Stock of the Company, $0.0001 par value per share (the “Common Stock”), as a result of the conversion of all of the issued and outstanding shares of Preferred Stock in connection with the closing of a firm commitment underwritten public offering (as such term is described in the Restated Certificate), then the fair market value per share of each Exercise Share shall be determined by taking the product of “x” and “y,” with “x” equal to the number of shares of Common Stock into which one share of the Series B Preferred Stock, could be converted on the Determination Date, and “y” equal to the fair market value of Common Stock on the Determination Date. For purposes of making this calculation, the fair market value of the Company’s Common Stock shall be determined as follows:

(1) If the Common Stock is traded on an exchange or is quoted on the NASDAQ Stock Market (“NASDAQ”), then the closing price on the day before the Determination Date;

(2) If Common Stock is not traded on an exchange or on the NASDAQ but is traded in the over-the-counter market, then the closing price on the day before the Determination Date; or

(3) If the Determination Date is the date on which the Common Stock is first sold to the public by the Company in a firm commitment public offering under the Securities Act of 1933, as amended (the “1933 Act”), then the initial public offering price (before deducting commissions, discounts or expenses) at which the Common Stock is sold in such offering;

(B) In the event that the Determination Date is the date of a liquidation, dissolution or winding up, or any Deemed Liquidation Event (as defined in the Restated Certificate), then the fair market value per share of each Exercise Share shall be determined by aggregating all amounts to be payable per share to holders of the Exercise Shares in the event of such liquidation, dissolution or winding up or Deemed Liquidation Event, plus all other amounts to be payable per share in respect of the Exercise Shares in liquidation, assuming for the purposes of this subsection that all of the Exercise Shares issuable upon exercise of all of the Warrants are outstanding at the Determination Date; or

(C) In all other cases, the fair market value per share of the Exercise Shares shall be determined in good faith by the unanimous approval of Company’s Board of Directors upon review of relevant factors.

5. Certificates for Shares. Upon the exercise of the purchase rights evidenced by this Warrant, one or more certificates for the number of Exercise Shares (or Conversation Shares, as the case may required) so purchased shall be issued as soon as practicable thereafter, and in any event within thirty (30) days of the delivery of the Notice of Exercise.

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6. Issuance of Shares. The Company covenants that the Exercise Shares, when issued pursuant to the exercise of this Warrant, and the Conversion Shares, when issued pursuant to the conversion of the Exercise Shares and the terms and conditions of the Restated Certificate will be duly and validly issued, fully paid and nonassessable and free from all taxes, liens, and charges with respect to the issuance thereof.

7. Adjustment of Exercise Price and Number of Shares. The number of and kind of Exercise Shares purchasable upon exercise of this Warrant and the Exercise Price shall be subject to adjustment from time to time as follows (it being agreed that similar adjustments with respect to the number and kind of Conversion Shares receivable upon conversion of the Exercise Shares and the conversion price of the Conversion Shares shall be subject to adjustment from time to time as provided for in the Restated Certificate):

(a) Subdivisions, Combinations and Other Issuances. If the Company shall at any time prior to the expiration of this Warrant subdivide the Exercise Shares, by split-up or otherwise, or combine its Exercise Shares, or issue additional shares of Exercise Shares as a dividend, the number of Exercise Shares issuable on the exercise of this Warrant shall forthwith be proportionately increased in the case of a subdivision or stock dividend, or proportionately decreased in the case of a combination. Appropriate adjustments shall also be made to the purchase price payable per share, but the aggregate purchase price payable for the total number of Exercise Shares purchasable under this Warrant (as adjusted) shall remain the same. Any adjustment under this Section 7(a) shall become effective at the close of business on the date the subdivision or combination becomes effective, or as of the record date of such dividend, or in the event that no record date is fixed, upon the making of such dividend.

(b) Reclassification, Reorganization and Consolidation. In the event of changes in the series or class of equity securities of the Company comprising the Exercise Shares by reason of stock dividends, splits, recapitalizations, reclassifications, combinations or exchanges of shares, separations, reorganizations, liquidations, or the like, the number and series or class of Exercise Shares available under the Warrant in the aggregate and the Exercise Price shall be correspondingly adjusted to give the Holder of the Warrant, on exercise for the same Aggregate Exercise Price, the total number, class, and kind of shares as the Holder would have owned had the Warrant been exercised prior to the event and had the Holder continued to hold such shares until after the event requiring adjustment; provided, however, that such adjustment shall not be made with respect to, and this Warrant shall terminate if not exercised prior to, the events set forth in Section 7 below. For purposes of this Section 7, the “Aggregate Exercise Price” shall mean the aggregate Exercise Price payable in connection with the exercise in full of this Warrant.

(c) Merger, Consolidation or Sale of Assets. If there shall be a merger or consolidation of the Company with or into another corporation (other than a merger or reorganization involving only a change in the state of incorporation of the Company or the acquisition by the Company of other businesses where the Company survives as a going concern), or the sale of all or substantially all of the Company’s capital stock or assets to any

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other person, then as a part of such transaction, provision shall be made so that the Holder shall thereafter be entitled to receive the number of shares of stock or other securities or property (including cash) of the Company, or of the successor corporation resulting from the merger, consolidation or sale, to which the Holder would have been entitled if the Holder had exercised its rights pursuant to this Warrant immediately prior thereto. In any such case, appropriate adjustment shall be made in the application of the provisions of this Section 7(c) to the end that the provisions of this Section 7(c) shall be applicable after that event in as nearly equivalent a manner as may be practicable

(d) Notice of Adjustment; Expiration. When any adjustment is required to be made in the number or kind of shares purchasable upon exercise of the Warrant or conversion of the Exercise Shares or in the Exercise Price, the Company shall promptly notify the holder of such event and of the number of Exercise Shares, Conversion Shares or other securities or property thereafter purchasable upon exercise of this Warrant, as applicable.

(e) Adjustment Pursuant to Restated Certificate. If the Series B Preferred Stock shall be adjusted pursuant to the Restated Certificate in a manner not set forth above in clauses (a) through (d) of this Section 7, the Exercise Shares shall be adjusted in the same manner as the Series B Preferred Stock in accordance with the Restated Certificate.

8. No Fractional Shares or Scrip. No fractional shares or scrip representing fractional shares shall be issued upon the exercise of this Warrant, but in lieu of such fractional shares the Company shall make a cash payment therefor on the basis of the Exercise Price then in effect.

9. Representations of the Company. The Company represents that all corporate actions on the part of the Company, its officers, directors and stockholders necessary for the sale and issuance of this Warrant, the Exercise Shares and the Conversion Shares have been taken.

10. Restrictive Legend.

The Shares (unless registered under the 1933 Act) shall be stamped or imprinted with a legend in substantially the following form:

THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AND HAVE BEEN ACQUIRED FOR INVESTMENT AND NOT WITH A VIEW TO, OR IN CONNECTION WITH, THE SALE OR DISTRIBUTION THEREOF. NO SUCH TRANSFER MAY BE EFFECTED WITHOUT AN EFFECTIVE REGISTRATION STATEMENT RELATED THERETO OR AN OPINION OF COUNSEL IN A FORM SATISFACTORY TO THE COMPANY THAT SUCH REGISTRATION IS NOT REQUIRED UNDER THE SECURITIES ACT OF 1933, AS AMENDED.

11. Warrants Transferable. With respect to any offer, sale or other disposition of this Warrant, Holder will give written notice to the Company prior thereto, describing briefly the manner thereof, together with a written opinion of Holder’s counsel, or other evidence if reasonably satisfactory to the Company, to the effect that such offer, sale or other distribution

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may be effected without registration or qualification (under any federal or state law then in effect). Upon receiving such written notice and reasonably satisfactory opinion, if so requested, or other evidence, the Company, as promptly as practicable, shall notify Holder that Holder may sell or otherwise dispose of this Warrant in accordance with the terms of the notice delivered to the Company. If a determination has been made pursuant to this Section 11 that the opinion of counsel for Holder, or other evidence, is not reasonably satisfactory to the Company, the Company shall so notify Holder promptly after such determination has been made. Each Warrant thus transferred shall bear a legend as to the applicable restrictions on transferability in order to ensure compliance with the 1933 Act, unless in the opinion of counsel for the Company such legend is not required in order to ensure compliance with the 1933 Act. The Company may issue stop transfer instructions to its transfer agent in connection with such restrictions. Subject to the foregoing transfers of this Warrant shall be registered upon registration books maintained for such purpose by or on behalf of the Company.

12. Early Termination. In the event of, at any time prior to the Expiration Date: (a) the consummation of an initial public offering of securities of the Company registered under the 1933 Act, (b) the automatic conversion of the Series B Preferred Stock pursuant to Section 5 of the Restated Certificate or (c) a Deemed Liquidation Event, the Company shall provide to the Holder fifteen (15) days advance written notice of the estimated closing date of such public offering, the effective date of such automatic conversion of the Series B Preferred Stock or the closing of such Deemed Liquidation Event. Unless the Holder exercises this Warrant pursuant to the terms of Section 3 within five (5) days of the receipt of such advance written notice, immediately prior to the date such public offering is closed, the effective date of such automatic conversion of the Series B Preferred Stock or the closing of such Deemed Liquidation Event, this Warrant shall (i) be automatically deemed exercised in full pursuant to Section 4 if the fair market value of each Exercise Share is greater than the Exercise Price or (ii) be automatically terminated if the fair market value each Exercise Share is equal to or less than the Exercise Price.

13. Market Stand-Off Agreement. The Holder hereby agrees that it will not, without the prior written consent of the managing underwriter, during the period beginning on and including the date that the Company’s Common Stock is first quoted on a national exchange and continuing through the close of trading on the date that is 180 days thereafter, or such other period as may be requested by the Company or an underwriter to comply with regulatory restrictions on (1) the publication or other distribution of research reports and (2) analyst recommendations and options, including, but not limited to, the restrictions contained in FINRA Rule 2711(f)(4) or NYSE Rule 472(f)(4), or any successor provisions or amendments thereto), (i) lend; offer; pledge; sell; contract to sell; sell any option or contract to purchase; purchase any option or contract to sell; grant any option, right, or warrant to purchase; or otherwise transfer or dispose of, directly or indirectly, any shares of Common Stock or any securities convertible into or exercisable or exchangeable (directly or indirectly) for Common Stock (whether such shares or any such securities are then owned by the Holder or are thereafter acquired) or (ii) enter into any swap or other arrangement that transfers to another, in whole or in part, any of the economic consequences of ownership of such securities, whether any such transaction described in clause (i) or (ii) above is to be settled by delivery of Common Stock or other securities, in cash, or otherwise. The foregoing provisions of this Section shall apply only to an initial public offering, shall not apply to the sale of any shares to an underwriter pursuant to an underwriting agreement, or the transfer of any shares to any trust for the direct or indirect benefit of the Holder or the

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immediate family of the Holder, provided that the trustee of the trust agrees to be bound in writing by the restrictions set forth herein, and provided further that any such transfer shall not involve a disposition for value (an “Estate Planning Transfer”), and shall be applicable to the Holder only if all officers and directors are subject to the same restrictions and the Company uses commercially reasonable efforts to obtain a similar agreement from all stockholders individually owning more than one percent (1%) of the Company’s outstanding Common Stock (after giving effect to conversion into Common Stock of all outstanding Preferred Stock). The underwriters in connection with such registration are intended third party beneficiaries of this Section and shall have the right, power, and authority to enforce the provisions hereof as though they were a party hereto. Each Holder further agrees to execute such agreements as may be reasonably requested by the underwriters in connection with such registration that are consistent with this Section or that are necessary to give further effect thereto. Any discretionary waiver or termination of the restrictions of any or all of such agreements by the Company or the underwriters shall apply pro rata to all Holders subject to such agreements, based on the number of shares subject to such agreements. Holder agrees that any transferee of the Warrant (or other securities) of the Company held by Holder shall be bound by this Section 13.

14. Rights of Stockholders. The Holder shall not be entitled, as a Warrant holder, to vote or receive dividends or be deemed the holder of the Exercise Shares or any other securities of the Company which may at any time be issuable on the exercise hereof for any purpose, nor shall anything contained herein be construed to confer upon the Holder, as such, any of the rights of a stockholder of the Company or any right to vote for the election of directors or upon any matter submitted to stockholders at any meeting thereof, or to give or withhold consent to any corporate action (whether upon any recapitalization, issuance of stock, reclassification of stock, change of par value, consolidation, merger, conveyance, or otherwise) or to receive notice of meetings, or to receive dividends or subscription rights or otherwise until the Warrant shall have been exercised and the Exercise Shares purchasable upon the exercise hereof shall have become deliverable, as provided herein.

15. Taxes. The issuance of the Exercise Shares upon the exercise of this Warrant, and the delivery of certificates or other instruments representing such Exercise Shares, shall be made without charge to the Holder for any tax or other charge of whatever nature in respect of such issuance and the Company shall bear any such taxes in respect of such issuance.

16. Lost Warrant, etc. Upon receipt by the Company of evidence reasonably satisfactory to the Company of the loss, theft, destruction or mutilation of this Warrant, and, in the case of loss, theft or destruction, of any indemnification undertaking by the Holder to the Company in customary form and, in the case of mutilation, upon surrender and cancellation of this Warrant, the Company shall execute and deliver to the Holder a new Warrant representing the right to purchase the Exercise Shares then underlying this Warrant. Whenever the Company is required to issue a new Warrant pursuant to the terms of this Warrant, such new Warrant (i) shall be of like tenor with this Warrant, (ii) shall represent, as indicated on the face of such new Warrant, the right to purchase the Exercise Shares then underlying this Warrant (or in the case of a new Warrant being issued pursuant to Section 11, the Exercise Shares designated by the Holder which, when added to the number of Exercise Shares underlying the other new Warrants issued in connection with such issuance, does not exceed the number of Exercise Shares then underlying this Warrant), (iii) shall have an issuance date, as indicated on the face of such new Warrant, which is the same as the issuance date of this Warrant, and (iv) shall have the same rights and conditions as this Warrant.

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17. Notices. All notices and other communications given or made pursuant to this Agreement shall be in writing and shall be deemed effectively given upon the earlier of actual receipt, or (a) personal delivery to the party to be notified, (b) when sent, if sent by electronic mail or facsimile during normal business hours of the recipient, and if not sent during normal business hours, then on the recipient’s next business day, (c) five (5) days after having been sent by registered or certified mail, return receipt requested, postage prepaid, or (d) one (1) business day after deposit with a nationally recognized overnight courier, freight prepaid, specifying next business day delivery, with written verification of receipt, and shall be addressed (i) if to the Holder, at the Holder’s address as set forth on the Schedule of Investors to the Purchase Agreement, and (ii) if to the Company, at 955 Massachusetts Avenue, Cambridge, Massachusetts, 02139, or at such other address as a party may designate by ten days advance written notice to the other party pursuant to the provisions above.

18. Waiver and Amendment. Any term of this Warrant may be amended or waived with the written consent of the Company and Holders of at least a Majority of the Conversion Shares, provided that all Warrants are similarly affected. Upon the effectuation of such amendment or waiver in conformance with this Section 16, the Company shall promptly give written notice thereof to the record holders of the Warrants who have not previously consented thereto in writing.

19. Governing Law. This Warrant and all actions arising out of or in connection with this Agreement shall be governed by and construed in accordance with the laws of the State of Delaware, without regard to the conflicts of law provisions of the State of Delaware or of any other state.

20. Rights and Obligations Survive Exercise of Warrant. Unless otherwise provided herein, the rights and obligations of the Company, of the Holder and of the holder of the Exercise Shares issued upon exercise of this Warrant, shall survive the exercise of this Warrant.

21. Severability. If one or more provisions of this Warrant are held to be unenforceable under applicable law, such provision(s) shall be excluded from this Warrant and the balance of this Warrant shall be interpreted as if such provision(s) were so excluded and shall be enforceable in accordance with its terms.

[Signature Page Follows]

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The Company has caused this Warrant to be issued as of the date first written above.

[Signature Page to Series B Preferred Stock Warrant]

EXHIBIT A

NOTICE OF EXERCISE

1. The undersigned hereby elects to purchase __________ shares of ____________ pursuant to the terms of the attached Warrant (the “Shares”).

2. Method of Exercise (Please initial the applicable blank):

3. Please issue a certificate or certificates representing said Shares in the name of the undersigned or in such other name as is specified below:

(Name)

(Address)

4. The undersigned hereby represents and warrants that the aforesaid Shares are being acquired for the account of the undersigned for investment and not with a view to, or for resale, in connection with the distribution thereof, and that the undersigned has no present intention of distributing or reselling such shares and all representations and warranties of the undersigned set forth in Sections 3 of the Purchase Agreement (as defined in the Warrant) are true and correct as of the date hereof.

EXHIBIT B

FORM OF TRANSFER

(To be signed only upon transfer of Warrant)

FOR VALUE RECEIVED, the undersigned hereby sells, assigns and transfers unto _______________________________________________ the right represented by the attached Warrant to purchase ____________ shares of ________________________ of X4 Pharmaceuticals, Inc. to which the attached Warrant relates, and appoints ______________ Attorney to transfer such right on the books of __________, with full power of substitution in the premises.

Dated: ____________________

Exhibit 4.5

THIS WARRANT, AND THE SECURITIES ISSUABLE UPON THE EXERCISE OF THIS WARRANT, HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “ACT”), OR ANY STATE SECURITIES LAWS. THEY MAY NOT BE SOLD, OFFERED FOR SALE, PLEDGED, OR HYPOTHECATED IN THE ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT RELATED THERETO OR AN OPINION OF COUNSEL (WHICH MAY BE COMPANY COUNSEL) REASONABLY SATISFACTORY TO THE COMPANY THAT SUCH REGISTRATION IS NOT REQUIRED UNDER THE ACT, OR ANY APPLICABLE STATE SECURITIES LAWS.

WARRANT AGREEMENT

To Purchase Shares of Preferred Stock of

X4 PHARMACEUTICALS, INC.

Dated as of October 19, 2018 (the “Effective Date”)

WHEREAS, X4 Pharmaceuticals, Inc., a Delaware corporation, has entered into a Loan and Security Agreement of even date herewith (the “Loan Agreement”) with Hercules Capital, Inc., a Maryland corporation, in its capacity as administrative and collateral agent, and Hercules Capital, Inc. (the “Warrantholder”) and the other lender parties thereto;

WHEREAS, the Company (as defined below) desires to grant to the Warrantholder, in consideration for, among other things, the financial accommodations provided for in the Loan Agreement, the right to purchase shares of Preferred Stock (as defined below) pursuant to this Warrant Agreement (the “Agreement”);

NOW, THEREFORE, in consideration of the Warrantholder executing and delivering the Loan Agreement and providing the financial accommodations contemplated therein, and in consideration of the mutual covenants and agreements contained herein, the Company and the Warrantholder agree as follows:

SECTION 1. GRANT OF THE RIGHT TO PURCHASE PREFERRED STOCK.

For value received, the Company hereby grants to the Warrantholder, and the Warrantholder is entitled, upon the terms and subject to the conditions hereinafter set forth, to subscribe for and purchase, from the Company, an aggregate number of fully paid and non-assessable shares of the Preferred Stock equal to the quotient derived by dividing (a) the Warrant Coverage (as defined below) by (b) the Exercise Price (defined below). The Exercise Price of such shares is subject to adjustment as provided in Section 8. As used herein, the following terms shall have the following meanings:

“Act” means the Securities Act of 1933, as amended.

“Charter” means the Company’s Articles of Incorporation, Certificate of Incorporation or other constitutional document, as may be amended from time to time.

“Common Stock” means the Company’s common stock, $0.001 par value per share;

“Company” means X4 Pharmaceuticals, Inc., a Delaware corporation, and any successor or surviving entity that assumes the obligations of the Company under this Agreement pursuant to Section 8(a).

“Equity Round” means any non-public offering of equity securities by the Company, after the Effective Date but prior to the consummation of an Initial Public Offering that results in the conversion of all preferred stock of the Company into Common Stock, in a transaction or series of related transactions principally for equity financing purposes in which the cash is received by the Company and/or debt of the Company is cancelled or converted in exchange for equity securities of the Company; provided that Equity Round shall not include additional closings of the Company’s Series B Preferred Stock round of financing.

1

“Exercise Price” means (a) if Preferred Stock means Series B Preferred Stock, $1.88 per share, or (b) if Preferred Stock means Next Round Stock, the lowest price per share of Next Round Stock paid by investors in the Next Round, in either case subject to adjustment pursuant to Section 8;

“Initial Public Offering” means the initial underwritten public offering of the Company’s Common Stock pursuant to a registration statement under the Act, which public offering has been declared effective by the Securities and Exchange Commission (“SEC”);

“Merger Event” means (i) any sale, lease, exclusive license or other transfer of all or substantially all assets of the Company or any merger or consolidation involving the Company in which the Company is not the surviving entity, or in which the outstanding shares of the Company’s capital stock are otherwise converted into or exchanged for shares of preferred stock, other securities or property of another entity; or (ii) any Deemed Liquidation Event as such term is defined in the Charter;

“Next Round” means the next Equity Round in which the Company issues and sells shares of its preferred stock and any options, warrants, rights or other securities that are exercisable, convertible or exchangeable into, or otherwise provide the right to purchase or acquire shares of such preferred stock for aggregate gross cash proceeds of at least $25,000,000;

“Preferred Stock” means, at the election of the Warrantholder, (A) the Series B Preferred Stock of the Company or (B) upon the closing of the Next Round, the class and series of the preferred stock of the Company and any options, warrants, rights or other securities that are exercisable, convertible or exchangeable into, or otherwise provide the right to purchase or acquire shares of preferred stock (such preferred stock, the “Next Round Stock”), and, to the extent provided in Sections 8(a) and (b), any other stock into or for which such Preferred Stock may be converted or exchanged, provided, that notwithstanding anything to the contrary contained in this Warrant, if all of the preferred stock of the Company is converted into Common Stock (automatically upon an Initial Public Offering or otherwise), “Preferred Stock”: shall thereafter refer to Common Stock, with the appropriate adjustment to the number of such shares of Common Stock issuable upon exercise of this Warrant;

“Purchase Price” means, with respect to any exercise of this Agreement, an amount equal to the Exercise Price as of the relevant time multiplied by the number of shares of Preferred Stock requested to be exercised under this Agreement pursuant to such exercise; and

“Warrant Coverage” means $396,000.

SECTION 2. TERM OF THE AGREEMENT.

Except as otherwise provided for herein, the term of this Agreement and the right to purchase Preferred Stock as granted herein (the “Warrant) shall commence on the Effective Date and shall be exercisable for a period ending upon the earlier to occur of (i) ten (10) years from the Effective Date.

SECTION 3. EXERCISE OF THE PURCHASE RIGHTS.

(a) Exercise. The purchase rights set forth in this Agreement are exercisable by the Warrantholder, in whole or in part, at any time, or from time to time, prior to the expiration of the term set forth in Section 2, by tendering to the Company at its principal office a notice of exercise in the form attached hereto as Exhibit I (the “Notice of Exercise”), duly completed and executed. Promptly upon receipt of the Notice of Exercise and the payment of the Purchase Price in accordance with the terms set forth below, and in no event later than three (3) days thereafter, the Company shall issue to the Warrantholder a certificate for the number of shares of Preferred Stock purchased and shall execute the acknowledgment of exercise in the form attached hereto as Exhibit II (the “Acknowledgment of Exercise”) indicating the number of shares which remain subject to future purchases, if any.

The Purchase Price may be paid at the Warrantholder’s election either (i) by cash or check, or (ii) by surrender of all or a portion of the Warrant for shares of Preferred Stock to be exercised under this Agreement and, if applicable, an amended Agreement representing the remaining number of shares purchasable hereunder, as determined below (“Net Issuance”). If the Warrantholder elects the Net Issuance method, the Company will issue Preferred Stock in accordance with the following formula:

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X = Y(A-B)

            A

Where:   X =       the number of shares of Preferred Stock to be issued to the Warrantholder.

For purposes of the above calculation, current fair market value of Preferred Stock shall mean with respect to each share of Preferred Stock:

(i) if the exercise is in connection with an Initial Public Offering, and if the Company’s Registration Statement relating to such Initial Public Offering has been declared effective by the SEC, then the fair market value per share shall be the initial “Price to Public” of the Common Stock specified in the final prospectus with respect to the offering;

(ii) if the exercise is after, and not in connection with an Initial Public Offering, and:

(A) if the Common Stock is traded on a securities exchange, the fair market value shall be deemed to be the prior day closing price before the day the current fair market value of the securities is being determined; or

(B) if the Common Stock is traded over-the-counter, the fair market value shall be deemed to be the prior day closing bid and asked price quoted on the NASDAQ system (or similar system) before the day the current fair market value of the securities is being determined;

(iii) if at any time the Common Stock is not listed on any securities exchange or quoted in the NASDAQ National Market or the over-the-counter market, the current fair market value of Preferred Stock shall be the highest price per share which the Company could obtain from a willing buyer (not a current employee or director) for shares of Common Stock sold by the Company, from authorized but unissued shares, as determined in good faith by its Board of Directors, unless the Company shall become subject to a Merger Event, in which case the fair market value of Preferred Stock shall be deemed to be the per share value received by the holders of the Company’s Preferred Stock on a common equivalent basis pursuant to such Merger Event.

Upon partial exercise by either cash or Net Issuance, the Company shall promptly issue an amended Agreement representing the remaining number of shares purchasable hereunder. All other terms and conditions of such amended Agreement shall be identical to those contained herein, including, but not limited to the Effective Date hereof.

(b) Exercise Prior to Expiration. To the extent this Agreement is not previously exercised as to all shares of Preferred Stock subject hereto, and if the fair market value of one share of the Preferred Stock is greater than the Exercise Price then in effect, this Agreement shall be deemed automatically exercised pursuant to Section 3(a) (even if not surrendered) immediately before its expiration. For purposes of such automatic exercise, the fair market value of one share of the Preferred Stock upon such expiration shall be determined pursuant to Section 3(a). To the extent this Agreement or any portion thereof is deemed automatically exercised pursuant to this Section 3(b), the Company agrees to promptly notify the Warrantholder of the number of shares of Preferred Stock, if any, the Warrantholder is to receive by reason of such automatic exercise.

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SECTION 4. RESERVATION OF SHARES.

During the term of this Agreement, the Company will at all times have authorized and reserved a sufficient number of shares of its Preferred Stock to provide for the exercise of the rights to purchase Preferred Stock as provided for herein, and shall have authorized and reserved a sufficient number of shares of its Common Stock to provide for the conversion of the shares of Preferred Stock issuable hereunder.

SECTION 5. NO FRACTIONAL SHARES OR SCRIP.

No fractional shares or scrip representing fractional shares shall be issued upon the exercise of this Agreement, but in lieu of such fractional shares the Company shall make a cash payment therefor upon the basis of the then fair market value of one share of Preferred Stock.

SECTION 6. NO RIGHTS AS SHAREHOLDER/STOCKHOLDER.

This Agreement does not entitle the Warrantholder to any voting rights or other rights as a shareholder/stockholder of the Company prior to the exercise of this Agreement.

SECTION 7. WARRANTHOLDER REGISTRY.

The Company shall maintain a registry showing the name and address of the registered holder of this Agreement. The Warrantholder’s initial address, for purposes of such registry, is set forth below the Warrantholder’s signature on this Agreement. The Warrantholder may change such address by giving written notice of such changed address to the Company.

SECTION 8. ADJUSTMENT RIGHTS.

The Exercise Price and the number of shares of Preferred Stock purchasable hereunder are subject to adjustment, as follows:

(a) Merger Event. If at any time there shall be Merger Event, this Warrant shall, on and after the closing thereof, automatically and without further action on the part of any party or other person, represent the right to receive the consideration (including, without limitation, cash, securities or other property (collectively, “Reference Property”)) payable on or in respect of all shares of Preferred Stock that are issuable hereunder as of immediately prior to the closing of such Merger Event less the Purchase Price for all such shares of Preferred Stock, and such Merger Event consideration shall be paid to Warrantholder as and when it is paid to the holders of the outstanding shares of Preferred Stock and this Warrant shall thereupon automatically terminate. Appropriate adjustment (as determined in good faith by the Company’s Board of Directors and reasonably acceptable to the Warrantholder) shall be made in the application of the provisions of this Agreement with respect to the rights and interests of the Warrantholder after the Merger Event to the end that the provisions of this Agreement (including adjustments of the Exercise Price, the ability of the Warrantholder to elect the class and series of Preferred Stock as set forth in the definition thereof, and adjustments to ensure that the provisions of this Section 8 shall thereafter be applicable, as nearly as possible, to the purchase rights under this Agreement in relation to any Reference Property thereafter acquirable upon exercise of such purchase rights) shall continue to be applicable in their entirety, and to the greatest extent possible. To the extent this Warrant or any portion thereof is deemed automatically exercised pursuant to this Section 8(a), the Company agrees to promptly notify the Warrantholder of the Reference Property, if any, the Warrantholder is to receive by reason of such automatic exercise. Notwithstanding anything to the contrary in this Warrant, if the aggregate fair market value of the Reference Property payable under this Section 8(a) is less than the aggregate Exercise Price of this Warrant, then this Warrant shall automatically terminate immediately prior to the closing of such Merger Event without and Reference Property or other consideration being paid to the Warrantholder.

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(b) Reclassification of Shares. Except for Merger Events subject to Sections 8(a) and 8(e), if the Company at any time shall, by combination, reclassification, exchange or subdivision of securities or otherwise, change any of the securities as to which purchase rights under this Agreement exist into the same or a different number of securities of any other class or classes, this Agreement shall thereafter represent the right to acquire such number and kind of securities as would have been issuable as the result of such change with respect to the securities which were subject to the purchase rights under this Agreement immediately prior to such combination, reclassification, exchange, subdivision or other change; provided to the extent the Warrantholder has the right to elect to receive upon exercise either Series B Preferred Stock or Next Round Stock, the adjustment under this clause (b) shall apply solely to the class and series of preferred stock that has been so combined, reclassified, exchanged or subdivided and shall not impair the Warrantholder’s right to elect to exercise the purchase rights for any other class or series of preferred stock. The provisions of this Section 8(b) shall similarly apply to any successive combination, reclassification, exchange, subdivision or other change.

(c) Subdivision or Combination of Shares. If the Company at any time shall combine or subdivide its Preferred Stock, (i) in the case of a subdivision, the Exercise Price shall be proportionately decreased and the number of shares of Preferred Stock issuable hereunder shall be proportionately increased, or (ii) in the case of a combination, the Exercise Price shall be proportionately increased and the number of shares of Preferred Stock issuable hereunder shall be proportionately decreased.

(d) Dividends. If the Company at any time while this Agreement is outstanding and unexpired shall:

(i) pay a dividend with respect to the Preferred Stock payable in Preferred Stock, then the Exercise Price shall be adjusted, from and after the date of determination of stockholders entitled to receive such dividend or distribution, to that price determined by multiplying the Exercise Price in effect immediately prior to such date of determination by a fraction (A) the numerator of which shall be the total number of shares of Preferred Stock outstanding immediately prior to such dividend or distribution, and (B) the denominator of which shall be the total number of shares of Preferred Stock outstanding immediately after such dividend or distribution; or

(ii) make any other dividend or distribution with respect to Preferred Stock (or stock into which the Preferred Stock is convertible), except any dividend or distribution specifically provided for in any other clause of this Section 8, then, in each such case, provision shall be made by the Company such that the Warrantholder shall receive upon exercise or conversion of this Warrant a proportionate share of any such dividend or distribution as though it were the holder of the Preferred Stock (or other stock for which the Preferred Stock is convertible) as of the record date fixed for the determination of the stockholders of the Company entitled to receive such dividend or distribution.

(e) Antidilution Rights. Additional antidilution rights applicable to the Preferred Stock purchasable hereunder are as set forth in the Charter and shall be applicable with respect to the Preferred Stock issuable hereunder. The Company shall promptly provide the Warrantholder with any restatement, amendment, modification or waiver of the Charter; provided, that no such amendment, modification or waiver shall impair or reduce the antidilution rights applicable to the Preferred Stock as of the date hereof unless such amendment, modification or waiver affects the rights of the Warrantholder with respect to the Preferred Stock in the same manner as it affects all other holders of Preferred Stock. The Company shall provide the Warrantholder with prior written notice of any issuance of its stock or other equity security to occur after the Effective Date of this Agreement, which notice shall include (a) the price at which such stock or security is to be sold, (b) the number of shares to be issued, and (c) such other information as necessary for the Warrantholder to determine if a dilutive event has occurred. For the avoidance of doubt, there shall be no duplicate anti-dilution adjustment pursuant to this subsection (e), the forgoing subsection (d) and the Charter.

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(f) Notice of Adjustments. If: (i) the Company shall declare any dividend or distribution upon its stock, whether in stock, cash, property or other securities; (ii) there shall be any Merger Event; (iii) there shall be an Initial Public Offering; or (iv) there shall be any voluntary dissolution, liquidation or winding up of the Company; then, in connection with each such event, the Company shall send to the Warrantholder: (A) at least thirty (30) days’ prior written notice of the date on which the books of the Company shall close or a record shall be taken for such dividend, distribution, subscription rights (specifying the date on which the holders of Preferred Stock shall be entitled thereto) or for determining rights to vote in respect of such Merger Event, dissolution, liquidation or winding up; (B) in the case of any such Merger Event, dissolution, liquidation or winding up, at least thirty (30) days’ prior written notice of the date when the same shall take place (and specifying the date on which the holders of Preferred Stock shall be entitled to exchange their Preferred Stock for securities or other property deliverable upon such Merger Event, dissolution, liquidation or winding up); and (C) in the case of an Initial Public Offering, the Company shall give the Warrantholder at least thirty (30) days’ written notice prior to the effective date thereof.

Each such written notice shall set forth, in reasonable detail, (i) the event requiring the notice, and (ii) if any adjustment is required to be made, (A) the amount of such adjustment, (B) the method by which such adjustment was calculated, (C) the adjusted Exercise Price (if the Exercise Price has been adjusted), and (D) the number of shares subject to purchase hereunder after giving effect to such adjustment, and shall be given in accordance with Section 12(g) below.

(g) Timely Notice. Failure to timely provide such notice required by Section 8(f) above shall entitle the Warrantholder to retain the benefit of the applicable notice period notwithstanding anything to the contrary contained in any insufficient notice received by the Warrantholder. For purposes of this Section 8(g), and notwithstanding anything to the contrary in Section 12(g), the notice period shall begin on the date the Warrantholder actually receives a written notice containing all the information required to be provided in such Section 12(g).

SECTION 9. REPRESENTATIONS, WARRANTIES AND COVENANTS OF THE COMPANY.

(a) Reservation of Preferred Stock. The Preferred Stock issuable upon exercise of the Warrantholder’s rights has been or, in the case of Preferred Stock issuable in the Next Round, will be duly and validly reserved and, when issued in accordance with the provisions of this Agreement, will be validly issued, fully paid and non-assessable, and will be free of any taxes, liens, charges or encumbrances of any nature whatsoever; provided, that the Preferred Stock issuable pursuant to this Agreement may be subject to restrictions on transfer under state and/or federal securities laws. The Company has made available to the Warrantholder true, correct and complete copies of its Charter and current bylaws. The issuance of certificates for shares of Preferred Stock upon exercise of this Agreement shall be made without charge to the Warrantholder for any issuance tax in respect thereof, or other cost incurred by the Company in connection with such exercise and the related issuance of shares of Preferred Stock; provided, that the Company shall not be required to pay any tax which may be payable in respect of any transfer and the issuance and delivery of any certificate in a name other than that of the Warrantholder.

(b) Due Authority. The execution and delivery by the Company of this Agreement and the performance of all obligations of the Company hereunder, including the issuance to the Warrantholder of the right to acquire the shares of Preferred Stock and the Common Stock into which it may be converted, have been duly authorized by all necessary corporate action on the part of the Company. This Agreement: (i) does not violate the Charter or the Company’s current bylaws; (ii) does not contravene any law or governmental rule, regulation or order applicable to the Company; and (iii) does not and will not contravene any provision of, or constitute a default under, any indenture, mortgage, contract or other instrument to which the Company is a party or by which it is bound. This Agreement constitutes a legal, valid and binding agreement of the Company, enforceable in accordance with its terms.

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(c) Consents and Approvals. No consent or approval of, giving of notice to, registration with, or taking of any other action in respect of any state, federal or other governmental authority or agency is required with respect to the execution, delivery and performance by the Company of its obligations under this Agreement, except for the filing of notices pursuant to Regulation D under the Act and any filing required by applicable state securities law, which filings will be effective by the time required thereby.

(d) Issued Securities. All issued and outstanding shares of Common Stock, Preferred Stock or any other securities of the Company have been duly authorized and validly issued and are fully paid and nonassessable. All outstanding shares of Common Stock, Preferred Stock and any other securities were issued in full compliance with all federal and state securities laws. In addition, as of the date immediately preceding the date of this Agreement:

(i) The authorized capital of the Company consists of (A) 116,500,000 shares of Common Stock, of which 4,830,406 shares are issued and outstanding, (B) 2,313,523 shares of Series Seed Preferred Stock, of which 1,516,136 shares are issued and outstanding and are convertible into an aggregate of 1,516,136 shares of Common Stock, (C) 22,000,000 shares of Series A Preferred Stock, of which 19,946,842 shares are issued and outstanding and are convertible into an aggregate of 19,946,842 shares of Common Stock, and (B) 25,100,000 shares of Series B Preferred Stock, of which 18,616,569 shares are issued and outstanding and are convertible into an aggregate of 18,616,569 shares of Common Stock.

(ii) The Company has reserved 10,200,000 shares of Common Stock for issuance under its Stock Option Plan(s), under which 7,572,819 options are outstanding. The Company has warrants presently outstanding to purchase 1,646,494 shares of Series A Preferred Stock and warrants presently outstanding to purchase 3,294,268 shares of Series B Preferred Stock. There are no other options, warrants, conversion privileges or other rights presently outstanding to purchase or otherwise acquire any authorized but unissued shares of the Company’s capital stock or other securities of the Company.

(iii) In accordance with the Company’s Charter, no stockholder of the Company has preemptive rights to purchase new issuances of the Company’s capital stock.

(e) Registration Rights. The Company agrees that the shares of Common Stock issued and issuable upon conversion of the shares of Preferred Stock issued and issuable upon exercise of this Warrant, and, at all times (if any) when the Preferred Stock shall be Common Stock, the shares of Preferred Stock issued and issuable upon exercise of this Warrant, shall have the “Piggyback,” and S-3 registration rights pursuant to and as set forth in the Company’s investor rights agreement or similar agreement (the “Investor Rights Agreement”) on a pari passu basis with the holders of outstanding shares of Preferred Stock who are parties thereto. The provisions set forth in the Company’s Investor Rights Agreement or similar agreement relating to such registration rights in effect as of the Effective Date may not be amended, modified or waived without the prior written consent of the Warrantholder unless such amendment, modification or waiver affects the rights associated with the shares of Preferred Stock issued and issuable upon exercise hereof in the same manner as such amendment, modification, or waiver affects the rights associated with all outstanding shares of Preferred Stock whose holders are parties thereto.

(f) Other Commitments to Register Securities. Except as set forth in this Agreement, the Company is not, pursuant to the terms of any other agreement currently in existence, under any obligation to register under the Act any of its presently outstanding securities or any of its securities which may hereafter be issued.

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(g) Exempt Transaction. Subject to the accuracy of the Warrantholder’s representations in Section 10, the issuance of the Preferred Stock upon exercise of this Agreement, and the issuance of the Common Stock upon conversion of the Preferred Stock, will each constitute a transaction exempt from (i) the registration requirements of Section 5 of the Act, in reliance upon Section 4(2) thereof, and (ii) the qualification requirements of the applicable state securities laws.

(h) Compliance with Rule 144. If the Warrantholder proposes to sell Preferred Stock issuable upon the exercise of this Agreement, or the Common Stock into which it is convertible, in compliance with Rule 144 promulgated by the SEC, then, upon the Warrantholder’s written request to the Company, the Company shall furnish to the Warrantholder, within ten days after receipt of such request, a written statement confirming the Company’s compliance with the filing requirements of the SEC as set forth in such Rule, as such Rule may be amended from time to time.

(i) Information Rights. During the term of this Warrant, in order to establish the valuation of the Warrant, the Warrantholder shall be entitled to the information rights contained in Sections 7.1(b) and 7.1(c) of the Loan Agreement, and Sections 7.1(b) and 7.1(c) of the Loan Agreement are hereby incorporated into this Agreement by this reference as though fully set forth herein, provided, however, that the Company shall not be required to deliver a Compliance Certificate once all Indebtedness (as defined in the Loan Agreement) owed by the Company to the Warrantholder has been repaid. The information rights set forth in this Section 9(i) are subject to the Warrantholder having confidentiality obligations with respect thereto reasonably acceptable to the Company.

SECTION 10. REPRESENTATIONS AND COVENANTS OF THE WARRANTHOLDER.

This Agreement has been entered into by the Company in reliance upon the following representations and covenants of the Warrantholder:

(a) Investment Purpose. The right to acquire Preferred Stock is being acquired for investment and not with a view to the sale or distribution of any part thereof, and the Warrantholder has no present intention of selling or engaging in any public distribution of such rights or the Preferred Stock except pursuant to an effective registration statement or an exemption from the registration requirements of the Act.

(b) Private Issue. The Warrantholder understands (i) that the Preferred Stock issuable upon exercise of this Agreement is not registered under the Act or qualified under applicable state securities laws on the ground that the issuance contemplated by this Agreement will be exempt from the registration and qualifications requirements thereof, and (ii) that the Company’s reliance on such exemption is predicated on the representations set forth in this Section 10.

(c) Financial Risk. The Warrantholder has such knowledge and experience in financial and business matters as to be capable of evaluating the merits and risks of its investment, and has the ability to bear the economic risks of its investment.

(d) Risk of No Registration. The Warrantholder understands that if the Company does not register with the SEC pursuant to Section 12 of the Securities Exchange Act of 1934 (the “1934 Act”), or file reports pursuant to Section 15(d) of the 1934 Act, or if a registration statement covering the securities under the Act is not in effect when it desires to sell (i) the rights to purchase Preferred Stock pursuant to this Agreement or (ii) the Preferred Stock issuable upon exercise of the right to purchase, it may be required to hold such securities for an indefinite period. The Warrantholder also understands that any sale of (A) its rights hereunder to purchase Preferred Stock or (B) Preferred Stock issued or issuable hereunder which might be made by it in reliance upon Rule 144 under the Act may be made only in accordance with the terms and conditions of that Rule.

(e) Accredited Investor. The Warrantholder is an “accredited investor” within the meaning of the Securities and Exchange Rule 501 of Regulation D, as presently in effect.

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SECTION 11. TRANSFERS.

Subject to compliance with applicable federal and state securities laws, this Agreement and all rights hereunder are transferable, in whole or in part, without charge to the holder hereof (except for transfer taxes) upon surrender of this Agreement properly endorsed. Each taker and holder of this Agreement, by taking or holding the same, consents and agrees that this Agreement, when endorsed in blank, shall be deemed negotiable, and that the holder hereof, when this Agreement shall have been so endorsed and its transfer recorded on the Company’s books, shall be treated by the Company and all other persons dealing with this Agreement as the absolute owner hereof for any purpose and as the person entitled to exercise the rights represented by this Agreement. The transfer of this Agreement shall be recorded on the books of the Company upon receipt by the Company of a notice of transfer in the form attached hereto as Exhibit III (the “Transfer Notice”), at its principal offices and the payment to the Company of all transfer taxes and other governmental charges imposed on such transfer. Until the Company receives such Transfer Notice, the Company may treat the registered owner hereof as the owner for all purposes.

SECTION 12. MISCELLANEOUS.

(a) Effective Date. The provisions of this Agreement shall be construed and shall be given effect in all respects as if it had been executed and delivered by the Company on the date hereof. This Agreement shall be binding upon any successors or assigns of the Company.

(b) Remedies. In the event of any default hereunder, the non-defaulting party may proceed to protect and enforce its rights either by suit in equity and/or by action at law, including but not limited to an action for damages as a result of any such default, and/or an action for specific performance for any default where the Warrantholder will not have an adequate remedy at law and where damages will not be readily ascertainable. The Company expressly agrees that it shall not oppose an application by the Warrantholder or any other person entitled to the benefit of this Agreement requiring specific performance of any or all provisions hereof or enjoining the Company from continuing to commit any such breach of this Agreement.

(c) No Impairment of Rights. The Company will not, by amendment of its Charter or through any other means, avoid or seek to avoid the observance or performance of any of the terms of this Agreement, but will at all times in good faith assist in the carrying out of all such terms and in the taking of all such actions as may be necessary or appropriate in order to protect the rights of the Warrantholder against impairment.

(d) Additional Documents. The Company, upon execution of this Agreement, shall provide the Warrantholder with certified resolutions with respect to the representations, warranties and covenants set forth in Sections 9(a) through 9(d), 9(f) and 9(g). The Company shall also supply documentation reasonably necessary to evaluate whether to exercise this Warrant, including without limitation, (i) any merger/purchase/asset sale agreement and related documents and estimated payout allocations to each of the respective shareholders, warrant and option holders in connection with a Merger Event, (ii) the most recent capitalization tables, and (iii) the most recent Charter, in the case of information provided pursuant to clauses (i) and (ii) above, subject to the Warrantholder having confidentiality obligations with respect thereto reasonably acceptable to the Company.

(e) Attorney’s Fees. In any litigation, arbitration or court proceeding between the Company and the Warrantholder relating hereto, the prevailing party shall be entitled to attorneys’ fees and expenses and all costs of proceedings incurred in enforcing this Agreement. For the purposes of this Section 12(e), attorneys’ fees shall include without limitation fees incurred in connection with the following: (i) contempt proceedings; (ii) discovery; (iii) any motion, proceeding or other activity of any kind in connection with an insolvency proceeding; (iv) garnishment, levy, and debtor and third party examinations; and (v) post-judgment motions and proceedings of any kind, including without limitation any activity taken to collect or enforce any judgment.

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(f) Severability. In the event any one or more of the provisions of this Agreement shall for any reason be held invalid, illegal or unenforceable, the remaining provisions of this Agreement shall be unimpaired, and the invalid, illegal or unenforceable provision shall be replaced by a mutually acceptable valid, legal and enforceable provision, which comes closest to the intention of the parties underlying the invalid, illegal or unenforceable provision.

(g) Notices. Except as otherwise provided herein, any notice, demand, request, consent, approval, declaration, service of process or other communication that is required, contemplated, or permitted under this Agreement or with respect to the subject matter hereof shall be in writing, and shall be deemed to have been validly served, given, delivered, and received upon the earlier of: (i) the day of transmission by facsimile or hand delivery if transmission or delivery occurs on a business day at or before 5:00 pm in the time zone of the recipient, or, if transmission or delivery occurs on a non-business day or after such time, the first business day thereafter, or the first business day after deposit with an overnight express service or overnight mail delivery service; or (ii) the third (3^rd) calendar day after deposit in the United States mails, with proper first class postage prepaid, and shall be addressed to the party to be notified as follows:

If to the Warrantholder:

HERCULES CAPITAL, INC.

Legal Department

Attention: Chief Legal Officer and Bryan Jadot

400 Hamilton Avenue, Suite 310

Palo Alto, CA 94301

Email:

Telephone:

(i) If to the Company:

X4 Pharmaceuticals, Inc.

Attention: Adam Mostafa and Brian Bowersox

955 Massachusetts Avenue, 4th Floor

Boston, MA 02139

Email:

Telephone:

or to such other address as each party may designate for itself by like notice.

(h) Entire Agreement; Amendments. This Agreement constitutes the entire agreement and understanding of the parties hereto in respect of the subject matter hereof, and supersedes and replaces in their entirety any prior proposals, term sheets, letters, negotiations or other documents or agreements, whether written or oral, with respect to the subject matter hereof (including the Warrantholder’s proposal letter dated September 13, 2018). None of the terms of this Agreement may be amended except by an instrument executed by each of the parties hereto.

(i) Headings. The various headings in this Agreement are inserted for convenience only and shall not affect the meaning or interpretation of this Agreement or any provisions hereof.

(j) No Strict Construction. The parties hereto have participated jointly in the negotiation and drafting of this Agreement. In the event an ambiguity or question of intent or interpretation arises, this Agreement shall be construed as if drafted jointly by the parties hereto and no presumption or burden of proof shall arise favoring or disfavoring any party by virtue of the authorship of any provisions of this Agreement.

(k) No Waiver. No omission or delay by the Warrantholder at any time to enforce any right or remedy reserved to it, or to require performance of any of the terms, covenants or provisions hereof by the Company at any time designated, shall be a waiver of any such right or remedy to which the Warrantholder is entitled, nor shall it in any way affect the right of the Warrantholder to enforce such provisions thereafter.

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(l) Survival. All agreements, representations and warranties contained in this Agreement or in any document delivered pursuant hereto shall be for the benefit of the Warrantholder and shall survive the execution and delivery of this Agreement and the expiration or other termination of this Agreement.

(m) Governing Law. This Agreement has been negotiated and delivered to Warrantholder in the State of California, and shall have been accepted by the Warrantholder in the State of California. Delivery of Preferred Stock to the Warrantholder by the Company under this Agreement is due in the State of California. This Agreement shall be governed by, and construed and enforced in accordance with, the laws of the State of Delaware, excluding conflict of laws principles that would cause the application of laws of any other jurisdiction.

(n) Consent to Jurisdiction and Venue. All judicial proceedings arising in or under or related to this Agreement may be brought in any state or federal court of competent jurisdiction located in the State of California. By execution and delivery of this Agreement, each party hereto generally and unconditionally: (i) consents to personal jurisdiction in Santa Clara County, State of California; (ii) waives any objection as to jurisdiction or venue in Santa Clara County, State of California; (c) agrees not to assert any defense based on lack of jurisdiction or venue in the aforesaid courts; and (iii) irrevocably agrees to be bound by any judgment rendered thereby in connection with this Agreement. Service of process on any party hereto in any action arising out of or relating to this Agreement shall be effective if given in accordance with the requirements for notice set forth in Section 12(g), and shall be deemed effective and received as set forth in Section 12(g). Nothing herein shall affect the right to serve process in any other manner permitted by law or shall limit the right of either party to bring proceedings in the courts of any other jurisdiction.

(o) Mutual Waiver of Jury Trial. Because disputes arising in connection with complex financial transactions are most quickly and economically resolved by an experienced and expert person and the parties wish applicable state and federal laws to apply (rather than arbitration rules), the parties desire that their disputes be resolved by a judge applying such applicable laws. EACH OF THE COMPANY AND THE WARRANTHOLDER SPECIFICALLY WAIVES ANY RIGHT IT MAY HAVE TO TRIAL BY JURY OF ANY CAUSE OF ACTION, CLAIM, CROSS-CLAIM, COUNTERCLAIM, THIRD PARTY CLAIM OR ANY OTHER CLAIM (COLLECTIVELY, “CLAIMS”) ASSERTED BY THE COMPANY AGAINST THE WARRANTHOLDER OR ITS ASSIGNEE OR BY THE WARRANTHOLDER OR ITS ASSIGNEE AGAINST THE COMPANY. This waiver extends to all such Claims, including Claims that involve Persons other than the Company and the Warrantholder; Claims that arise out of or are in any way connected to the relationship between the Company and the Warrantholder; and any Claims for damages, breach of contract, specific performance, or any equitable or legal relief of any kind, arising out of this Agreement.

(p) Judicial Reference. If the waiver of jury trial set forth above is ineffective or unenforceable, the parties agree that all Claims shall be resolved by reference to a private judge sitting without a jury, pursuant to Code of Civil Procedure Section 638, before a mutually acceptable referee or, if the parties cannot agree, a referee selected by the Presiding Judge of Santa Clara County, California. Such proceeding shall be conducted in Santa Clara County, California, with Delaware rules of evidence and discovery applicable to such proceeding.

(q) Prejudgment Relief. In the event Claims are to be resolved by arbitration, either party may seek from a court of competent jurisdiction identified in Section 12(n), any prejudgment order, writ or other relief and have such prejudgment order, writ or other relief enforced to the fullest extent permitted by law notwithstanding that all Claims are otherwise subject to resolution by judicial reference.

(r) Counterparts. This Agreement and any amendments, waivers, consents or supplements hereto may be executed in any number of counterparts, and by different parties hereto in separate counterparts, each of which when so delivered shall be deemed an original, but all of which counterparts shall constitute but one and the same instrument.

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[Remainder of Page Intentionally Left Blank]

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IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be executed by its officers thereunto duly authorized as of the Effective Date.

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EXHIBIT I

NOTICE OF EXERCISE

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EXHIBIT II

ACKNOWLEDGMENT OF EXERCISE

The undersigned [____________________________________], hereby acknowledges receipt of the “Notice of Exercise” from Hercules Capital, Inc., to purchase [____] shares of the Series [__] Preferred Stock of [_________________], pursuant to the terms of the Warrant Agreement by and between X4 Pharmaceuticals, Inc. and Hercules Capital, Inc. dated September [__], 2018 (the “Agreement”), and further acknowledges that [______] shares remain subject to purchase under the terms of the Agreement.

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EXHIBIT III

TRANSFER NOTICE

(To transfer or assign the foregoing Agreement execute this form and supply required information. Do not use this form to purchase shares.)

FOR VALUE RECEIVED, the foregoing Agreement and all rights evidenced thereby are hereby transferred and assigned to

Signature Guaranteed:                                                                                                                           

NOTE: The signature to this Transfer Notice must correspond with the name as it appears on the face of the Agreement, without alteration or enlargement or any change whatever. Officers of corporations and those acting in a fiduciary or other representative capacity should file proper evidence of authority to assign the foregoing Agreement.

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Exhibit 4.6

WARRANT MODIFICATION AGREEMENT

This Warrant Modification Agreement is entered into as of December 11, 2018 between Hercules Capital, Inc. (the “Warrantholder”) and X4 Pharmaceuticals, Inc. (the “Company”).

Recitals

A. On October 19, 2018, the Company issued to Warrantholder a warrant (the “Warrant”) to purchase shares of its Series B Preferred Stock or Next Round Stock on such terms as set forth therein. Any terms not specifically defined herein shall have the meanings set forth in the Warrant.

B. In connection with an amendment to the Loan Agreement of even date herewith, the Company and the Warrantholder now desire to modify the Warrant.

Now, therefore, for good and valuable consideration, the receipt of which is hereby acknowledged, the Company and Warrantholder agree as follows:

1. Notwithstanding Section 8(a) of the Warrant, the Merger (as defined below) shall not be deemed as “Merger Event” under the Warrant, and the Warrant shall continue in full force and effect following the closing of the Merger, and thereafter the Warrant shall be exercisable for shares of Arsanis Common Stock (as defined below) with the Exercise Price under the Warrant being equal to $1.88 per share, subject to appropriate adjustment for the Preferred Stock Exchange Ratio (as defined in the Merger Agreement (as defined below)) following the Merger. For purposes hereof, the “Merger Agreement” shall mean that certain Agreement and Plan of Merger, dated November 26, 2018, as may be amended from time to time, by and among Arsanis, Inc., a Delaware corporation (“Arsanis”), Artemis AC Corp., a Delaware corporation and a wholly owned subsidiary of Arsanis (“Merger Sub”) and the Company, pursuant to which, among other things and subject to the terms and conditions of the Merger Agreement, Merger Sub will merge with and into the Company, with the Company continuing as a wholly owned subsidiary of Arsanis and the surviving corporation of the merger (the “Merger”), pursuant to which each share of the Company’s Series B Preferred Stock will be cancelled and exchanged for a number of shares of Arsanis’ common stock, par value $0.001 per share (the “Arsanis Common Stock”), equal to the Preferred Stock Exchange Ratio.

2. The Company shall not sign or enter into any agreement that will modify, alter or change the rights of Warrantholder under the Warrant without the written consent of the Warrantholder.

3. Except as specifically set forth in this Warrant Modification Agreement, the Warrant remains unmodified and in full force and effect.

4. This Warrant Modification Agreement may be executed in any number of counterparts, and by different parties hereto in separate counterparts, each of which when so delivered shall be deemed an original, but all of which counterparts shall constitute but one and the same instrument.

***

IN WITNESS WHEREOF, the parties hereto have caused this Warrant Modification to be executed by its officers thereunto duly authorized as of the date set forth above.

[signature page]

Exhibit 10.1.1

X4 PHARMACEUTICALS, INC.

2015 EMPLOYEE, DIRECTOR AND CONSULTANT EQUITY INCENTIVE PLAN

Unless otherwise specified or unless the context otherwise requires, the following terms, as used in this X4 Pharmaceuticals, Inc. 2015 Employee, Director and Consultant Equity Incentive Plan, have the following meanings:

Administrator means the Board of Directors, unless it has delegated power to act on its behalf to the Committee, in which case the Administrator means the Committee.

Affiliate means a corporation which, for purposes of Section 424 of the Code, is a parent or subsidiary of the Company, direct or indirect.

Agreement means an agreement between the Company and a Participant delivered pursuant to the Plan and pertaining to a Stock Right, in such form as the Administrator shall approve.

Board of Directors means the Board of Directors of the Company.

Cause means, with respect to a Participant (a) dishonesty with respect to the Company or any Affiliate, (b) insubordination, substantial malfeasance or non-feasance of duty, (c) unauthorized disclosure of confidential information, (d) breach by a Participant of any provision of any employment, consulting, advisory, nondisclosure, non-competition or similar agreement between the Participant and the Company or any Affiliate, and (e) conduct substantially prejudicial to the business of the Company or any Affiliate; provided, however, that any provision in an agreement between a Participant and the Company or an Affiliate, which contains a conflicting definition of Cause for termination and which is in effect at the time of such termination, shall supersede this definition with respect to that Participant. The determination of the Administrator as to the existence of Cause will be conclusive on the Participant and the Company.

Code means the United States Internal Revenue Code of 1986, as amended including any successor statute, regulation and guidance thereto.

Committee means the committee of the Board of Directors to which the Board of Directors has delegated power to act under or pursuant to the provisions of the Plan.

Common Stock means shares of the Company’s common stock, $.001 par value per share.

Company means X4 Pharmaceuticals, Inc., a Delaware corporation.

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Consultant means any natural person who is an advisor or consultant that provides bona fide services to the Company or its Affiliates, provided that such services are not in connection with the offer or sale of securities in a capital raising transaction, and do not directly or indirectly promote or maintain a market for the Company’s or its Affiliates’ securities.

Disability or Disabled means permanent and total disability as defined in Section 22(e)(3) of the Code.

Employee means any employee of the Company or of an Affiliate (including, without limitation, an employee who is also serving as an officer or director of the Company or of an Affiliate), designated by the Administrator to be eligible to be granted one or more Stock Rights under the Plan.

Exchange Act means the Securities Exchange Act of 1934, as amended.

Fair Market Value of a Share of Common Stock means:

(1) If the Common Stock is listed on a national securities exchange or traded in the over-the-counter market and sales prices are regularly reported for the Common Stock, the closing or, if not applicable, the last price of the Common Stock on the composite tape or other comparable reporting system for the trading day on the applicable date and if such applicable date is not a trading day, the last market trading day prior to such date;

(2) If the Common Stock is not traded on a national securities exchange but is traded on the over-the-counter market, if sales prices are not regularly reported for the Common Stock for the trading day referred to in clause (1), and if bid and asked prices for the Common Stock are regularly reported, the mean between the bid and the asked price for the Common Stock at the close of trading in the over-the-counter market for the trading day on which Common Stock was traded on the applicable date and if such applicable date is not a trading day, the last market trading day prior to such date; and

(3) If the Common Stock is neither listed on a national securities exchange nor traded in the over-the-counter market, such value as the Administrator, in good faith, shall determine.

ISO means an option intended to qualify as an incentive stock option under Section 422 of the Code.

Non-Qualified Option means an option which is not intended to qualify as an ISO.

Option means an ISO or Non-Qualified Option granted under the Plan.

Participant means an Employee, director or Consultant of the Company or an Affiliate to whom one or more Stock Rights are granted under the Plan. As used herein, “Participant” shall include “Participant’s Survivors” where the context requires.

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Plan means this X4 Pharmaceuticals, Inc. 2015 Employee, Director and Consultant Equity Incentive Plan.

Securities Act means the Securities Act of 1933, as amended.

Shares means shares of the Common Stock as to which Stock Rights have been or may be granted under the Plan or any shares of capital stock into which the Shares are changed or for which they are exchanged within the provisions of Paragraph 3 of the Plan. The Shares issued under the Plan may be authorized and unissued shares or shares held by the Company in its treasury, or both.

Stock-Based Award means a grant by the Company under the Plan of an equity award or an equity based award which is not an Option or a Stock Grant.

Stock Grant means a grant by the Company of Shares under the Plan.

Stock Right means a right to Shares or the value of Shares of the Company granted pursuant to the Plan — an ISO, a Non-Qualified Option, a Stock Grant or a Stock-Based Award.

Survivor means a deceased Participant’s legal representatives and/or any person or persons who acquired the Participant’s rights to a Stock Right by will or by the laws of descent and distribution.

The Plan is intended to encourage ownership of Shares by Employees and directors of and certain Consultants to the Company and its Affiliates in order to attract and retain such people, to induce them to work for the benefit of the Company or of an Affiliate and to provide additional incentive for them to promote the success of the Company or of an Affiliate. The Plan provides for the granting of ISOs, Non-Qualified Options, Stock Grants and Stock-Based Awards.

(a) The number of Shares which may be issued from time to time pursuant to this Plan shall be 625,000, or the equivalent of such number of Shares after the Administrator, in its sole discretion, has interpreted the effect of any stock split, stock dividend, combination, recapitalization or similar transaction in accordance with Paragraph 24 of the Plan.

(b) If an Option ceases to be “outstanding”, in whole or in part (other than by exercise), or if the Company shall reacquire (at not more than its original issuance price) any Shares issued pursuant to a Stock Grant or Stock-Based Award, or if any Stock Right expires or is forfeited, cancelled, or otherwise terminated or results in any Shares not being issued, the unissued or reacquired Shares which were subject to such Stock Right shall again be available for issuance from time to time pursuant to this Plan. Notwithstanding the foregoing, if a Stock Right is

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exercised, in whole or in part, by tender of Shares or if the Company or an Affiliate’s tax withholding obligation is satisfied by withholding Shares, the number of Shares deemed to have been issued under the Plan for purposes of the limitation set forth in Paragraph 3(a) above shall be the number of Shares that were subject to the Stock Right or portion thereof, and not the net number of Shares actually issued. However, in the case of ISOs, the foregoing provisions shall be subject to any limitations under the Code.

The Administrator of the Plan will be the Board of Directors, except to the extent the Board of Directors delegates its authority to the Committee, in which case the Committee shall be the Administrator. Subject to the provisions of the Plan, the Administrator is authorized to:

(a) Interpret the provisions of the Plan and all Stock Rights and to make all rules and determinations which it deems necessary or advisable for the administration of the Plan;

(b) Determine which Employees, directors and Consultants shall be granted Stock Rights;

(c) Determine the number of Shares for which a Stock Right or Stock Rights shall be granted;

(d) Specify the terms and conditions upon which a Stock Right or Stock Rights may be granted;

(e) Amend any term or condition of any outstanding Stock Right, including, without limitation, to reduce or increase the exercise price or purchase price, accelerate the vesting schedule or extend the expiration date, provided that (i) such term or condition as amended is permitted by the Plan; (ii) any such amendment shall not impair the rights of a Participant under any Stock Right previously granted without such Participant’s consent or in the event of death of the Participant the Participant’s Survivors; and (iii) any such amendment shall be made only after the Administrator determines whether such amendment would cause any adverse tax consequences to the Participant, including, but not limited to, the annual vesting limitation contained in Section 422(d) of the Code and described in Paragraph 6(b)(iv) below with respect to ISOs and pursuant to Section 409A of the Code;

(f) Buy out for a payment in cash or Shares, a Stock Right previously granted and/or cancel any such Stock Right and grant in substitution therefor other Stock Rights, covering the same or a different number of Shares and having an exercise price or purchase price per share which may be lower or higher than the exercise price or purchase price of the cancelled Stock Right, based on such terms and conditions as the Administrator shall establish and the Participant shall accept; and

(g) Adopt any sub-plans applicable to residents of any specified jurisdiction as it deems necessary or appropriate in order to comply with or take advantage of any tax or other laws applicable to the Company, any Affiliate or to Participants or to otherwise facilitate the administration of the Plan, which sub-plans may include additional restrictions or conditions applicable to Stock Rights or Shares issuable pursuant to a Stock Right;

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provided, however, that all such interpretations, rules, determinations, terms and conditions shall be made and prescribed in the context of not causing any adverse tax consequences under Section 409A of the Code and preserving the tax status under Section 422 of the Code of those Options which are designated as ISOs. Subject to the foregoing, the interpretation and construction by the Administrator of any provisions of the Plan or of any Stock Right granted under it shall be final, unless otherwise determined by the Board of Directors, if the Administrator is the Committee. In addition, if the Administrator is the Committee, the Board of Directors may take any action under the Plan that would otherwise be the responsibility of the Committee.

To the extent permitted under applicable law, the Board of Directors or the Committee may allocate all or any portion of its responsibilities and powers to any one or more of its members and may delegate all or any portion of its responsibilities and powers to any other person selected by it. The Board of Directors or the Committee may revoke any such allocation or delegation at any time.

The Administrator will, in its sole discretion, name the Participants in the Plan; provided, however, that each Participant must be an Employee, director or Consultant of the Company or of an Affiliate at the time a Stock Right is granted. Notwithstanding the foregoing, the Administrator may authorize the grant of a Stock Right to a person not then an Employee, director or Consultant of the Company or of an Affiliate; provided, however, that the actual grant of such Stock Right shall be conditioned upon such person becoming eligible to become a Participant at or prior to the time of the execution of the Agreement evidencing such Stock Right. ISOs may be granted only to Employees who are deemed to be residents of the United States for tax purposes. Non-Qualified Options, Stock Grants and Stock-Based Awards may be granted to any Employee, director or Consultant of the Company or an Affiliate. The granting of any Stock Right to any individual shall neither entitle that individual to, nor disqualify him or her from, participation in any other grant of Stock Rights or any grant under any other benefit plan established by the Company or any Affiliate for Employees, directors or Consultants.

Each Option shall be set forth in writing in an Option Agreement, duly executed by the Company and, to the extent required by law or requested by the Company, by the Participant. The Administrator may provide that Options be granted subject to such terms and conditions, consistent with the terms and conditions specifically required under this Plan, as the Administrator may deem appropriate including, without limitation, subsequent approval by the shareholders of the Company of this Plan or any amendments thereto. The Option Agreements shall be subject to at least the following terms and conditions:

(a) Non-Qualified Options: Each Option intended to be a Non-Qualified Option shall be subject to the terms and conditions which the Administrator determines to be appropriate and in the best interest of the Company, subject to the following minimum standards for any such Non-Qualified Option:

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(b) ISOs: Each Option intended to be an ISO shall be issued only to an Employee who is deemed to be a resident of the United States for tax purposes, and shall be subject to the following terms and conditions, with such additional restrictions or changes as the Administrator determines are appropriate but not in conflict with Section 422 of the Code and relevant regulations and rulings of the Internal Revenue Service:

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Each Stock Grant to a Participant shall state the principal terms in an Agreement duly executed by the Company and, to the extent required by law or requested by the Company, by the Participant. The Agreement shall be in a form approved by the Administrator and shall contain terms and conditions which the Administrator determines to be appropriate and in the best interest of the Company, subject to the following minimum standards:

(a) Each Agreement shall state the purchase price per share, if any, of the Shares covered by each Stock Grant, which purchase price shall be determined by the Administrator but shall not be less than the minimum consideration required by the Delaware General Corporation Law, if any, on the date of the grant of the Stock Grant;

(b) Each Agreement shall state the number of Shares to which the Stock Grant pertains; and

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(c) Each Agreement shall include the terms of any right of the Company to restrict or reacquire the Shares subject to the Stock Grant, including the time and events upon which such rights shall accrue and the purchase price therefor, if any.

The Administrator shall have the right to grant other Stock-Based Awards based upon the Common Stock having such terms and conditions as the Administrator may determine, including, without limitation, the grant of Shares based upon certain conditions, the grant of securities convertible into Shares and the grant of stock appreciation rights, phantom stock awards or stock units. The principal terms of each Stock-Based Award shall be set forth in an Agreement, duly executed by the Company and, to the extent required by law or requested by the Company, by the Participant. The Agreement shall be in a form approved by the Administrator and shall contain terms and conditions which the Administrator determines to be appropriate and in the best interest of the Company.

The Company intends that the Plan and any Stock-Based Awards granted hereunder be exempt from the application of Section 409A of the Code or meet the requirements of paragraphs (2), (3) and (4) of subsection (a) of Section 409A of the Code, to the extent applicable, and be operated in accordance with Section 409A so that any compensation deferred under any Stock-Based Award (and applicable investment earnings) shall not be included in income under Section 409A of the Code. Any ambiguities in the Plan shall be construed to effect the intent as described in this Paragraph 8.

An Option (or any part or installment thereof) shall be exercised by giving written notice to the Company or its designee (in a form acceptable to the Administrator, which may include electronic notice), together with provision for payment of the aggregate exercise price in accordance with this Paragraph for the Shares as to which the Option is being exercised, and upon compliance with any other condition(s) set forth in the Option Agreement. Such notice shall be signed by the person exercising the Option (which signature may be provided electronically in a form acceptable to the Administrator), shall state the number of Shares with respect to which the Option is being exercised and shall contain any representation required by the Plan or the Option Agreement. Payment of the exercise price for the Shares as to which such Option is being exercised shall be made (a) in United States dollars in cash or by check, or (b) at the discretion of the Administrator, through delivery of shares of Common Stock held for at least six months (if required to avoid negative accounting treatment) having a Fair Market Value equal as of the date of the exercise to the aggregate cash exercise price for the number of Shares as to which the Option is being exercised, or (c) at the discretion of the Administrator, by having the Company retain from the Shares otherwise issuable upon exercise of the Option, a number of Shares having a Fair Market Value equal as of the date of exercise to the aggregate exercise price for the number of Shares as to which the Option is being exercised, or (d) at the discretion of the Administrator (after consideration of applicable securities, tax and accounting implications), by delivery of the grantee’s personal recourse note bearing interest payable not less than annually at no less than 100% of the applicable Federal rate, as defined in Section 1274(d) of the Code, or (e) at the discretion of the Administrator, in accordance with a cashless exercise program established with a

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securities brokerage firm, and approved by the Administrator, or (f) at the discretion of the Administrator, by any combination of (a), (b), (c), (d) and (e) above or (g) at the discretion of the Administrator, by payment of such other lawful consideration as the Administrator may determine. Notwithstanding the foregoing, the Administrator shall accept only such payment on exercise of an ISO as is permitted by Section 422 of the Code.

The Company shall then reasonably promptly deliver the Shares as to which such Option was exercised to the Participant (or to the Participant’s Survivors, as the case may be). In determining what constitutes “reasonably promptly,” it is expressly understood that the issuance and delivery of the Shares may be delayed by the Company in order to comply with any law or regulation (including, without limitation, state securities or “blue sky” laws) which requires the Company to take any action with respect to the Shares prior to their issuance. The Shares shall, upon delivery, be fully paid, non-assessable Shares.

Any Stock Grant or Stock-Based Award requiring payment of a purchase price for the Shares as to which such Stock Grant or Stock-Based Award is being granted shall be made (a) in United States dollars in cash or by check, or (b) at the discretion of the Administrator, through delivery of shares of Common Stock held for at least six months (if required to avoid negative accounting treatment) and having a Fair Market Value equal as of the date of payment to the purchase price of the Stock Grant or Stock-Based Award, or (c) at the discretion of the Administrator (after consideration of applicable securities, tax and accounting implications), by delivery of the grantee’s personal recourse note bearing interest payable not less than annually at no less than 100% of the applicable Federal rate, as defined in Section 1274(d) of the Code, or (d) at the discretion of the Administrator, by any combination of (a), (b) and (c) above; or (e) at the discretion of the Administrator, by payment of such other lawful consideration as the Administrator may determine.

The Company shall when required by the applicable Agreement, reasonably promptly deliver the Shares as to which such Stock Grant or Stock-Based Award was made to the Participant (or to the Participant’s Survivors, as the case may be), subject to any escrow provision set forth in the applicable Agreement. In determining what constitutes “reasonably promptly,” it is expressly understood that the issuance and delivery of the Shares may be delayed by the Company in order to comply with any law or regulation (including, without limitation, state securities or “blue sky” laws) which requires the Company to take any action with respect to the Shares prior to their issuance.

No Participant to whom a Stock Right has been granted shall have rights as a shareholder with respect to any Shares covered by such Stock Right except after due exercise of an Option or issuance of Shares as set forth in any Agreement, tender of the aggregate exercise or purchase price, if any, for the Shares being purchased and registration of the Shares in the Company’s share register in the name of the Participant.

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By its terms, a Stock Right granted to a Participant shall not be transferable by the Participant other than (i) by will or by the laws of descent and distribution, or (ii) as approved by the Administrator in its discretion and set forth in the applicable Agreement provided that no Stock Right may be transferred by a Participant for value. Notwithstanding the foregoing, an ISO transferred except in compliance with clause (i) above shall no longer qualify as an ISO. The designation of a beneficiary of a Stock Right by a Participant, with the prior approval of the Administrator and in such form as the Administrator shall prescribe, shall not be deemed a transfer prohibited by this Paragraph. Except as provided above during the Participant’s lifetime a Stock Right shall only be exercisable by or issued to such Participant (or his or her legal representative) and shall not be assigned, pledged or hypothecated in any way (whether by operation of law or otherwise) and shall not be subject to execution, attachment or similar process. Any attempted transfer, assignment, pledge, hypothecation or other disposition of any Stock Right or of any rights granted thereunder contrary to the provisions of this Plan, or the levy of any attachment or similar process upon a Stock Right, shall be null and void.

Except as otherwise provided in a Participant’s Option Agreement, in the event of a termination of service (whether as an Employee, director or Consultant) with the Company or an Affiliate before the Participant has exercised an Option, the following rules apply:

(a) A Participant who ceases to be an Employee, director or Consultant of the Company or of an Affiliate (for any reason other than termination for Cause, Disability, or death for which events there are special rules in Paragraphs 14, 15, and 16, respectively), may exercise any Option granted to him or her to the extent that the Option is exercisable on the date of such termination of service, but only within such term as the Administrator has designated in a Participant’s Option Agreement.

(b) Except as provided in Subparagraph (c) below, or Paragraph 15 or 16, in no event may an Option intended to be an ISO, be exercised later than three months after the Participant’s termination of employment.

(c) The provisions of this Paragraph, and not the provisions of Paragraph 15 or 16, shall apply to a Participant who subsequently becomes Disabled or dies after the termination of employment, director status or consultancy; provided, however, in the case of a Participant’s Disability or death within three months after the termination of employment, director status or consultancy, the Participant or the Participant’s Survivors may exercise the Option within one year after the date of the Participant’s termination of service, but in no event after the date of expiration of the term of the Option.

(d) Notwithstanding anything herein to the contrary, if subsequent to a Participant’s termination of employment, termination of director status or termination of consultancy, but prior to the exercise of an Option, the Administrator determines that, either prior or subsequent to the Participant’s termination, the Participant engaged in conduct which would constitute Cause, then such Participant shall forthwith cease to have any right to exercise any Option.

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(e) A Participant to whom an Option has been granted under the Plan who is absent from the Company or an Affiliate because of temporary disability (any disability other than a Disability as defined in Paragraph 1 hereof), or who is on leave of absence for any purpose, shall not, during the period of any such absence, be deemed, by virtue of such absence alone, to have terminated such Participant’s employment, director status or consultancy with the Company or with an Affiliate, except as the Administrator may otherwise expressly provide; provided, however, that, for ISOs, any leave of absence granted by the Administrator of greater than ninety days, unless pursuant to a contract or statute that guarantees the right to reemployment, shall cause such ISO to become a Non-Qualified Option on the 181st day following such leave of absence.

(f) Except as required by law or as set forth in a Participant’s Option Agreement, Options granted under the Plan shall not be affected by any change of a Participant’s status within or among the Company and any Affiliates, so long as the Participant continues to be an Employee, director or Consultant of the Company or any Affiliate.

Except as otherwise provided in a Participant’s Option Agreement, the following rules apply if the Participant’s service (whether as an Employee, director or Consultant) with the Company or an Affiliate is terminated for Cause prior to the time that all his or her outstanding Options have been exercised:

(a) All outstanding and unexercised Options as of the time the Participant is notified his or her service is terminated for Cause will immediately be forfeited.

(b) Cause is not limited to events which have occurred prior to a Participant’s termination of service, nor is it necessary that the Administrator’s finding of Cause occur prior to termination. If the Administrator determines, subsequent to a Participant’s termination of service but prior to the exercise of an Option, that either prior or subsequent to the Participant’s termination the Participant engaged in conduct which would constitute Cause, then the right to exercise any Option is forfeited.

Except as otherwise provided in a Participant’s Option Agreement:

(a) A Participant who ceases to be an Employee, director or Consultant of the Company or of an Affiliate by reason of Disability may exercise any Option granted to such Participant:

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(b) A Disabled Participant may exercise the Option only within the period ending one year after the date of the Participant’s termination of service due to Disability, notwithstanding that the Participant might have been able to exercise the Option as to some or all of the Shares on a later date if the Participant had not been terminated due to Disability and had continued to be an Employee, director or Consultant or, if earlier, within the originally prescribed term of the Option.

(c) The Administrator shall make the determination both of whether Disability has occurred and the date of its occurrence (unless a procedure for such determination is set forth in another agreement between the Company and such Participant, in which case such procedure shall be used for such determination). If requested, the Participant shall be examined by a physician selected or approved by the Administrator, the cost of which examination shall be paid for by the Company.

Except as otherwise provided in a Participant’s Option Agreement:

(a) In the event of the death of a Participant while the Participant is an Employee, director or Consultant of the Company or of an Affiliate, such Option may be exercised by the Participant’s Survivors:

(b) If the Participant’s Survivors wish to exercise the Option, they must take all necessary steps to exercise the Option within one year after the date of death of such Participant, notwithstanding that the decedent might have been able to exercise the Option as to some or all of the Shares on a later date if he or she had not died and had continued to be an Employee, director or Consultant or, if earlier, within the originally prescribed term of the Option.

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In the event of a termination of service (whether as an Employee, director or Consultant) with the Company or an Affiliate for any reason before the Participant has accepted a Stock Grant or a Stock-Based Award and paid the purchase price, if required, such grant shall terminate.

For purposes of this Paragraph 17 and Paragraph 18 below, a Participant to whom a Stock Grant or a Stock-Based Award has been issued under the Plan who is absent from work with the Company or with an Affiliate because of temporary disability (any disability other than a Disability as defined in Paragraph 1 hereof), or who is on leave of absence for any purpose, shall not, during the period of any such absence, be deemed, by virtue of such absence alone, to have terminated such Participant’s employment, director status or consultancy with the Company or with an Affiliate, except as the Administrator may otherwise expressly provide.

In addition, for purposes of this Paragraph 17 and Paragraph 18 below, any change of employment or other service within or among the Company and any Affiliates shall not be treated as a termination of employment, director status or consultancy so long as the Participant continues to be an Employee, director or Consultant of the Company or any Affiliate.

Except as otherwise provided in a Participant’s Stock Grant Agreement, in the event of a termination of service (whether as an Employee, director or Consultant), other than termination for Cause, Disability, or death for which events there are special rules in Paragraphs 19, 20, and 21, respectively, before all forfeiture provisions or Company rights of repurchase shall have lapsed, then the Company shall have the right to cancel or repurchase that number of Shares subject to a Stock Grant as to which the Company’s forfeiture or repurchase rights have not lapsed.

Except as otherwise provided in a Participant’s Stock Grant Agreement, the following rules apply if the Participant’s service (whether as an Employee, director or Consultant) with the Company or an Affiliate is terminated for Cause:

(a) All Shares subject to any Stock Grant that remain subject to forfeiture provisions or as to which the Company shall have a repurchase right shall be immediately forfeited to the Company.

(b) Cause is not limited to events which have occurred prior to a Participant’s termination of service, nor is it necessary that the Administrator’s finding of Cause occur prior to termination. If the Administrator determines, subsequent to a Participant’s termination of service, that either prior or subsequent to the Participant’s termination the Participant engaged in conduct which would constitute Cause, then all Shares subject to any Stock Grant that remained subject to forfeiture provisions or as to which the Company had a repurchase right on the date of termination shall be immediately forfeited to the Company.

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Except as otherwise provided in a Participant’s Stock Grant Agreement, the following rules apply if a Participant ceases to be an Employee, director or Consultant of the Company or of an Affiliate by reason of Disability: to the extent the forfeiture provisions or the Company’s rights of repurchase have not lapsed on the date of Disability, they shall be exercisable; provided, however, that in the event such forfeiture provisions or rights of repurchase lapse periodically, such provisions or rights shall lapse to the extent of a pro rata portion of the Shares subject to such Stock Grant through the date of Disability as would have lapsed had the Participant not become Disabled. The proration shall be based upon the number of days accrued prior to the date of Disability.

The Administrator shall make the determination both as to whether Disability has occurred and the date of its occurrence (unless a procedure for such determination is set forth in another agreement between the Company and such Participant, in which case such procedure shall be used for such determination). If requested, the Participant shall be examined by a physician selected or approved by the Administrator, the cost of which examination shall be paid for by the Company.

Except as otherwise provided in a Participant’s Stock Grant Agreement, the following rules apply in the event of the death of a Participant while the Participant is an Employee, director or Consultant of the Company or of an Affiliate: to the extent the forfeiture provisions or the Company’s rights of repurchase have not lapsed on the date of death, they shall be exercisable; provided, however, that in the event such forfeiture provisions or rights of repurchase lapse periodically, such provisions or rights shall lapse to the extent of a pro rata portion of the Shares subject to such Stock Grant through the date of death as would have lapsed had the Participant not died. The proration shall be based upon the number of days accrued prior to the Participant’s date of death.

Unless the offering and sale of the Shares shall have been effectively registered under the Securities Act, the Company shall be under no obligation to issue Shares under the Plan unless and until the following conditions have been fulfilled:

(a) The person who receives a Stock Right shall warrant to the Company, prior to the receipt of Shares, that such person is acquiring such Shares for his or her own account, for investment, and not with a view to, or for sale in connection with, the distribution of any such Shares, in which event the person acquiring such Shares shall be bound by the provisions of the following legend (or a legend in substantially similar form) which shall be endorsed upon the certificate evidencing the Shares issued pursuant to such exercise or such grant:

“The shares represented by this certificate have been taken for investment and they may not be sold or otherwise transferred by any person, including a pledgee, unless (1) either (a) a Registration Statement with respect to such shares shall be effective under the Securities Act of 1933, as amended, or (b) the Company shall have received an opinion of counsel satisfactory to it that an exemption from registration under such Act is then available, and (2) there shall have been compliance with all applicable state securities laws.”

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(b) At the discretion of the Administrator, the Company shall have received an opinion of its counsel that the Shares may be issued in compliance with the Securities Act without registration thereunder.

Upon the dissolution or liquidation of the Company, all Options granted under this Plan which as of such date shall not have been exercised and all Stock Grants and Stock-Based Awards which have not been accepted, to the extent required under the applicable Agreement, will terminate and become null and void; provided, however, that if the rights of a Participant or a Participant’s Survivors have not otherwise terminated and expired, the Participant or the Participant’s Survivors will have the right immediately prior to such dissolution or liquidation to exercise or accept any Stock Right to the extent that the Stock Right is exercisable or subject to acceptance as of the date immediately prior to such dissolution or liquidation. Upon the dissolution or liquidation of the Company, any outstanding Stock-Based Awards shall immediately terminate unless otherwise determined by the Administrator or specifically provided in the applicable Agreement.

Upon the occurrence of any of the following events, a Participant’s rights with respect to any Stock Right granted to him or her hereunder shall be adjusted as hereinafter provided, unless otherwise specifically provided in a Participant’s Agreement:

(a) Stock Dividends and Stock Splits. If (i) the shares of Common Stock shall be subdivided or combined into a greater or smaller number of shares or if the Company shall issue any shares of Common Stock as a stock dividend on its outstanding Common Stock, or (ii) additional shares or new or different shares or other securities of the Company or other non-cash assets are distributed with respect to such shares of Common Stock, each Stock Right and the number of shares of Common Stock deliverable thereunder shall be appropriately increased or decreased proportionately, and appropriate adjustments shall be made including, in the exercise or purchase price per share, to reflect such events. The number of Shares subject to the limitations in Paragraph 3(a) shall also be proportionately adjusted upon the occurrence of such events.

(b) Corporate Transactions. If the Company is to be consolidated with or acquired by another entity in a merger, consolidation, or sale of all or substantially all of the Company’s assets other than a transaction to merely change the state of incorporation (a “Corporate Transaction”), the Administrator or the board of directors of any entity assuming the obligations of the Company hereunder (the “Successor Board”), shall, as to outstanding Options, either (i) make appropriate provision for the continuation of such Options by substituting on an equitable basis for the Shares then subject to such Options either the consideration payable with respect to the outstanding shares of Common Stock in connection with the Corporate Transaction or securities of any successor or

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acquiring entity; or (ii) upon written notice to the Participants, provide that such Options must be exercised (either (A) to the extent then exercisable or, (B) at the discretion of the Administrator, any such Options being made partially or fully exercisable for purposes of this Subparagraph), within a specified number of days of the date of such notice, at the end of which period such Options which have not been exercised shall terminate; or (iii) terminate such Options in exchange for payment of an amount equal to the consideration payable upon consummation of such Corporate Transaction to a holder of the number of shares of Common Stock into which such Option would have been exercisable (either (A) to the extent then exercisable or, (B) at the discretion of the Administrator, any such Options being made partially or fully exercisable for purposes of this Subparagraph) less the aggregate exercise price thereof. For purposes of determining the payments to be made pursuant to Subclause (iii) above, in the case of a Corporate Transaction the consideration for which, in whole or in part, is other than cash, the consideration other than cash shall be valued at the fair value thereof as determined in good faith by the Board of Directors.

With respect to outstanding Stock Grants, the Administrator or the Successor Board, shall make appropriate provision for the continuation of such Stock Grants on the same terms and conditions by substituting on an equitable basis for the Shares then subject to such Stock Grants either the consideration payable with respect to the outstanding Shares of Common Stock in connection with the Corporate Transaction or securities of any successor or acquiring entity. In lieu of the foregoing, in connection with any Corporate Transaction, the Administrator may provide that, upon consummation of the Corporate Transaction, each outstanding Stock Grant shall be terminated in exchange for payment of an amount equal to the consideration payable upon consummation of such Corporate Transaction to a holder of the number of shares of Common Stock comprising such Stock Grant (to the extent such Stock Grant is no longer subject to any forfeiture or repurchase rights then in effect or, at the discretion of the Administrator, all forfeiture and repurchase rights being waived upon such Corporate Transaction).

In taking any of the actions permitted under this Paragraph 24(b), the Administrator shall not be obligated by the Plan to treat all Stock Rights, all Stock Rights held by a Participant, or all Stock Rights of the same type, identically.

(c) Recapitalization or Reorganization. In the event of a recapitalization or reorganization of the Company other than a Corporate Transaction pursuant to which securities of the Company or of another corporation are issued with respect to the outstanding shares of Common Stock, a Participant upon exercising an Option or accepting a Stock Grant after the recapitalization or reorganization shall be entitled to receive for the price paid upon such exercise or acceptance if any, the number of replacement securities which would have been received if such Option had been exercised or Stock Grant accepted prior to such recapitalization or reorganization.

(d) Adjustments to Stock-Based Awards. Upon the happening of any of the events described in Subparagraphs (a), (b) or (c) above, any outstanding Stock-Based Award shall be appropriately adjusted to reflect the events described in such Subparagraphs. The Administrator or the Successor Board shall determine the specific adjustments to be made under this Paragraph 24, including, but not limited to the effect of any Corporate Transaction and, subject to Paragraph 4, its determination shall be conclusive.

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(e) Modification of Options. Notwithstanding the foregoing, any adjustments made pursuant to Subparagraph (a), (b) or (c) above with respect to Options shall be made only after the Administrator determines whether such adjustments would (i) constitute a “modification” of any ISOs (as that term is defined in Section 424(h) of the Code) or (ii) cause any adverse tax consequences for the holders of Options, including, but not limited to, pursuant to Section 409A of the Code. If the Administrator determines that such adjustments made with respect to Options would constitute a modification or other adverse tax consequence, it may refrain from making such adjustments, unless the holder of an Option specifically agrees in writing that such adjustment be made and such writing indicates that the holder has full knowledge of the consequences of such “modification” on his or her income tax treatment with respect to the Option. This paragraph shall not apply to the acceleration of the vesting of any ISO that would cause any portion of the ISO to violate the annual vesting limitation contained in Section 422(d) of the Code, as described in Paragraph 6(b)(iv).

Except as expressly provided herein, no issuance by the Company of shares of stock of any class, or securities convertible into shares of stock of any class, shall affect, and no adjustment by reason thereof shall be made with respect to, the number or price of shares subject to Stock Rights. Except as expressly provided herein, no adjustments shall be made for dividends paid in cash or in property (including without limitation, securities) of the Company prior to any issuance of Shares pursuant to a Stock Right.

No fractional shares shall be issued under the Plan and the person exercising a Stock Right shall receive from the Company cash in lieu of such fractional shares equal to the Fair Market Value thereof.

The Administrator, at the written request of any Participant, may in its discretion take such actions as may be necessary to convert such Participant’s ISOs (or any portions thereof) that have not been exercised on the date of conversion into Non-Qualified Options at any time prior to the expiration of such ISOs, regardless of whether the Participant is an Employee of the Company or an Affiliate at the time of such conversion. At the time of such conversion, the Administrator (with the consent of the Participant) may impose such conditions on the exercise of the resulting Non-Qualified Options as the Administrator in its discretion may determine, provided that such conditions shall not be inconsistent with this Plan. Nothing in the Plan shall be deemed to give any Participant the right to have such Participant’s ISOs converted into Non-Qualified Options, and no such conversion shall occur until and unless the Administrator takes appropriate action. The Administrator, with the consent of the Participant, may also terminate any portion of any ISO that has not been exercised at the time of such conversion.

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In the event that any federal, state, or local income taxes, employment taxes, Federal Insurance Contributions Act (“F.I.C.A.”) withholdings or other amounts are required by applicable law or governmental regulation to be withheld from the Participant’s salary, wages or other remuneration in connection with the issuance of a Stock Right or Shares under the Plan or for any other reason required by law, the Company may withhold from the Participant’s compensation, if any, or may require that the Participant advance in cash to the Company, or to any Affiliate of the Company which employs or employed the Participant, the statutory minimum amount of such withholdings unless a different withholding arrangement, including the use of shares of the Company’s Common Stock or a promissory note, is authorized by the Administrator (and permitted by law). For purposes hereof, the fair market value of the shares withheld for purposes of payroll withholding shall be determined in the manner set forth under the definition of Fair Market Value provided in Paragraph 1 above, as of the most recent practicable date prior to the date of exercise. If the Fair Market Value of the shares withheld is less than the amount of payroll withholdings required, the Participant may be required to advance the difference in cash to the Company or the Affiliate employer. The Administrator in its discretion may condition the exercise of an Option for less than the then Fair Market Value on the Participant’s payment of such additional withholding.

Each Employee who receives an ISO must agree to notify the Company in writing immediately after the Employee makes a Disqualifying Disposition of any Shares acquired pursuant to the exercise of an ISO. A Disqualifying Disposition is defined in Section 424(c) of the Code and includes any disposition (including any sale or gift) of such Shares before the later of (a) two years after the date the Employee was granted the ISO, or (b) one year after the date the Employee acquired Shares by exercising the ISO, except as otherwise provided in Section 424(c) of the Code. If the Employee has died before such Shares are sold, these holding period requirements do not apply and no Disqualifying Disposition can occur thereafter.

The Plan will terminate on January 15, 2025, the date which is ten years from the earlier of the date of its adoption by the Board of Directors and the date of its approval by the shareholders of the Company. The Plan may be terminated at an earlier date by vote of the shareholders or the Board of Directors of the Company; provided, however, that any such earlier termination shall not affect any Agreements executed prior to the effective date of such termination. Termination of the Plan shall not affect any Stock Rights theretofore granted.

The Plan may be amended by the shareholders of the Company. The Plan may also be amended by the Administrator, including, without limitation, to the extent necessary to qualify any or all outstanding Stock Rights granted under the Plan or Stock Rights to be granted under the Plan for favorable federal income tax treatment as may be afforded incentive stock options under Section 422 of the Code (including deferral of taxation upon exercise), and to the extent necessary

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to qualify the Shares issuable under the Plan for listing on any national securities exchange or quotation in any national automated quotation system of securities dealers. Any amendment approved by the Administrator which the Administrator determines is of a scope that requires shareholder approval shall be subject to obtaining such shareholder approval. Any modification or amendment of the Plan shall not, without the consent of a Participant, adversely affect his or her rights under a Stock Right previously granted to him or her. With the consent of the Participant affected, the Administrator may amend outstanding Agreements in a manner which may be adverse to the Participant but which is not inconsistent with the Plan. In the discretion of the Administrator, outstanding Agreements may be amended by the Administrator in a manner which is not adverse to the Participant.

Nothing in this Plan or any Agreement shall be deemed to prevent the Company or an Affiliate from terminating the employment, consultancy or director status of a Participant, nor to prevent a Participant from terminating his or her own employment, consultancy or director status or to give any Participant a right to be retained in employment or other service by the Company or any Affiliate for any period of time.

This Plan shall be construed and enforced in accordance with the law of the State of Delaware.

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Exhibit 10.1.2

X4 PHARMACEUTICALS, INC.

STOCK OPTION AGREEMENT - INCORPORATED TERMS AND CONDITIONS

AGREEMENT made as of the date of grant set forth in the Stock Option Grant Notice by and between X4 Pharmaceuticals, Inc. (the “Company”), a Delaware corporation, and the individual whose name appears on the Stock Option Grant Notice (the “Participant”).

WHEREAS, the Company desires to grant to the Participant an Option to purchase shares of its common stock, $0.001 par value per share (the “Shares”), under and for the purposes set forth in the Company’s 2015 Employee, Director and Consultant Equity Incentive Plan (the “Plan”);

WHEREAS, the Company and the Participant understand and agree that any terms used and not defined herein have the same meanings as in the Plan; and

WHEREAS, the Company and the Participant each intend that the Option granted herein shall be of the type set forth in the Stock Option Grant Notice.

NOW, THEREFORE, in consideration of the mutual covenants hereinafter set forth and for other good and valuable consideration, the parties hereto agree as follows:

The Company hereby grants to the Participant the right and option to purchase all or any part of an aggregate of the number of Shares set forth in the Stock Option Grant Notice, on the terms and conditions and subject to all the limitations set forth herein, under United States securities and tax laws, and in the Plan, which is incorporated herein by reference. The Participant acknowledges receipt of a copy of the Plan.

The exercise price of the Shares covered by the Option shall be the amount per Share set forth in the Stock Option Grant Notice, subject to adjustment, as provided in the Plan, in the event of a stock split, reverse stock split or other events affecting the holders of Shares after the date hereof (the “Exercise Price”). Payment shall be made in accordance with Paragraph 9 of the Plan.

Subject to the terms and conditions set forth in this Agreement and the Plan, the Option granted hereby shall become vested and exercisable as set forth in the Stock Option Grant Notice and is subject to the other terms and conditions of this Agreement and the Plan.

This Option shall terminate on the Option Expiration Date as specified in the Stock Option Grant Notice and, if this Option is designated in the Stock Option Grant Notice as an ISO and the Participant owns as of the date hereof more than 10% of the total combined voting power of all classes of capital stock of the Company or an Affiliate, such date may not be more than five years from the date of this Agreement, but shall be subject to earlier termination as provided herein or in the Plan.

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If the Participant ceases to be an Employee, director or Consultant of the Company or of an Affiliate for any reason other than the death or Disability of the Participant, or termination of the Participant for Cause (the “Termination Date”), the Option to the extent then vested and exercisable pursuant to Section 3 hereof as of the Termination Date, and not previously terminated in accordance with this Agreement, may be exercised within three months after the Termination Date, or on or prior to the Option Expiration Date as specified in the Stock Option Grant Notice, whichever is earlier, but may not be exercised thereafter except as set forth below. In such event, the unvested portion of the Option shall not be exercisable and shall expire and be cancelled on the Termination Date.

If this Option is designated in the Stock Option Grant Notice as an ISO and the Participant ceases to be an Employee of the Company or of an Affiliate but continues after termination of employment to provide service to the Company or an Affiliate as a director or Consultant, this Option shall continue to vest in accordance with Section 3 above as if this Option had not terminated until the Participant is no longer providing services to the Company. In such case, this Option shall automatically convert and be deemed a Non-Qualified Option as of the date that is three months from termination of the Participant’s employment and this Option shall continue on the same terms and conditions set forth herein until such Participant is no longer providing service to the Company or an Affiliate.

Notwithstanding the foregoing, in the event of the Participant’s Disability or death within three months after the Termination Date, the Participant or the Participant’s Survivors may exercise the Option within one year after the Termination Date, but in no event after the Option Expiration Date as specified in the Stock Option Grant Notice.

In the event the Participant’s service is terminated by the Company or an Affiliate for Cause, the Participant’s right to exercise any unexercised portion of this Option even if vested shall cease immediately as of the time the Participant is notified his or her service is terminated for Cause, and this Option shall thereupon terminate. Notwithstanding anything herein to the contrary, if subsequent to the Participant’s termination, but prior to the exercise of the Option, the Administrator determines that, either prior or subsequent to the Participant’s termination, the Participant engaged in conduct which would constitute Cause, then the Participant shall immediately cease to have any right to exercise the Option and this Option shall thereupon terminate.

In the event of the Disability of the Participant, as determined in accordance with the Plan, the Option shall be exercisable within one year after the Participant’s termination of service due to Disability or, if earlier, on or prior to the Option Expiration Date as specified in the Stock Option Grant Notice. In such event, the Option shall be exercisable:

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In the event of the death of the Participant while an Employee, director or Consultant of the Company or of an Affiliate, the Option shall be exercisable by the Participant’s Survivors within one year after the date of death of the Participant or, if earlier, on or prior to the Option Expiration Date as specified in the Stock Option Grant Notice. In such event, the Option shall be exercisable:

Subject to the terms and conditions of this Agreement, the Option may be exercised by written notice to the Company or its designee, in substantially the form of Exhibit A attached hereto (or in such other form acceptable to the Company, which may include electronic notice). Such notice shall state the number of Shares with respect to which the Option is being exercised and shall be signed by the person exercising the Option (which signature may be provided electronically in a form acceptable to the Company). Payment of the Exercise Price for such Shares shall be made in accordance with Paragraph 9 of the Plan. The Company shall deliver such Shares as soon as practicable after the notice shall be received, provided, however, that the Company may delay issuance of such Shares until completion of any action or obtaining of any consent, which the Company deems necessary under any applicable law (including, without limitation, state securities or “blue sky” laws). The Shares as to which the Option shall have been so exercised shall be registered in the Company’s share register in the name of the person so exercising the Option (or, if the Option shall be exercised by the Participant and if the Participant shall so request in the notice exercising the Option, shall be registered in the Company’s share register in the name of the Participant and another person jointly, with right of survivorship) and shall be delivered as provided above to or upon the written order of the person exercising the Option. In the event the Option shall be exercised, pursuant to Section 4 hereof, by any person other than the Participant, such notice shall be accompanied by appropriate proof of the right of such person to exercise the Option. All Shares that shall be purchased upon the exercise of the Option as provided herein shall be fully paid and nonassessable.

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Exercise of this Option to the extent above stated may be made in part at any time and from time to time within the above limits, except that no fractional share shall be issued pursuant to this Option.

The Option shall not be transferable by the Participant otherwise than by will or by the laws of descent and distribution. If this Option is a Non-Qualified Option then it may also be transferred pursuant to a qualified domestic relations order as defined by the Code or Title I of the Employee Retirement Income Security Act or the rules thereunder. Except as provided above in this paragraph, the Option shall be exercisable, during the Participant’s lifetime, only by the Participant (or, in the event of legal incapacity or incompetency, by the Participant’s guardian or representative) and shall not be assigned, pledged or hypothecated in any way (whether by operation of law or otherwise) and shall not be subject to execution, attachment or similar process. Any attempted transfer, assignment, pledge, hypothecation or other disposition of the Option or of any rights granted hereunder contrary to the provisions of this Section 7, or the levy of any attachment or similar process upon the Option shall be null and void.

The Participant shall have no rights as a stockholder with respect to Shares subject to this Agreement until registration of the Shares in the Company’s share register in the name of the Participant. Except as is expressly provided in the Plan with respect to certain changes in the capitalization of the Company, no adjustment shall be made for dividends or similar rights for which the record date is prior to the date of such registration.

The Plan contains provisions covering the treatment of Options in a number of contingencies such as stock splits and mergers. Provisions in the Plan for adjustment with respect to stock subject to Options and the related provisions with respect to successors to the business of the Company are hereby made applicable hereunder and are incorporated herein by reference.

The Participant acknowledges and agrees that (i) any income or other taxes due from the Participant with respect to this Option or the Shares issuable upon exercise of this Option shall be the Participant’s responsibility; (ii) the Participant was free to use professional advisors of his or her choice in connection with this Agreement, has received advice from his or her professional advisors in connection with this Agreement, understands its meaning and import, and is entering into this Agreement freely and without coercion or duress; (iii) the Participant has not received and is not relying upon any advice, representations or assurances made by or on behalf of the Company or any Affiliate or any employee of or counsel to the Company or any Affiliate regarding any tax or other effects or implications of the Option, the Shares or other matters contemplated by this Agreement and (iv) neither the Administrator, the Company, its Affiliates, nor any of its officers or directors, shall be held liable for any applicable costs, taxes, or penalties associated with the Option if, in fact, the Internal Revenue Service were to determine that the Option constitutes deferred compensation under Section 409A of the Code.

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If this Option is designated in the Stock Option Grant Notice as a Non-Qualified Option or if the Option is converted into a Non-Qualified Option and such Non-Qualified Option is exercised, the Participant agrees that the Company may withhold from the Participant’s remuneration, if any, the minimum statutory amount of federal, state and local withholding taxes attributable to such amount that is considered compensation includable in such person’s gross income. At the Company’s discretion, the amount required to be withheld may be withheld in cash from such remuneration, or in kind from the Shares otherwise deliverable to the Participant on exercise of the Option. The Participant further agrees that, if the Company does not withhold an amount from the Participant’s remuneration sufficient to satisfy the Company’s income tax withholding obligation, the Participant will reimburse the Company on demand, in cash, for the amount under-withheld.

Unless the offering and sale of the Shares to be issued upon the particular exercise of the Option shall have been effectively registered under the Securities Act of 1933, as now in force or hereafter amended (the “1933 Act”), the Company shall be under no obligation to issue the Shares covered by such exercise unless the Company has determined that such exercise and issuance would be exempt from the registration requirements of the 1933 Act and until the following conditions have been fulfilled:

“The shares represented by this certificate have been taken for investment and they may not be sold or otherwise transferred by any person, including a pledgee, unless (1) either (a) a Registration Statement with respect to such shares shall be effective under the Securities Act of 1933, as amended, or (b) the Company shall have received an opinion of counsel satisfactory to it that an exemption from registration under such Act is then available, and (2) there shall have been compliance with all applicable state securities laws;” and

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12.1 The Shares acquired by the Participant pursuant to the exercise of the Option granted hereby shall not be transferred by the Participant except as permitted herein.

12.2 In the event of the Participant’s termination of service for any reason, the Company shall have the option, but not the obligation, to repurchase all or any part of the Shares issued pursuant to this Agreement (including, without limitation, Shares purchased after termination of service, Disability or death in accordance with Section 4 hereof). In the event the Company does not, upon the termination of service of the Participant (as described above), exercise its option pursuant to this Section 12.2, the restrictions set forth in the balance of this Agreement shall not thereby lapse, and the Participant for himself or herself, his or her heirs, legatees, executors, administrators and other successors in interest, agrees that the Shares shall remain subject to such restrictions. The following provisions shall apply to a repurchase under this Section 12.2:

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12.3 It shall be a condition precedent to the validity of any sale or other transfer of any Shares by the Participant that the following restrictions be complied with (except as otherwise provided in this Section 12):

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12.4 In the event that the Participant or his or her successor in interest fails to deliver the Shares to be repurchased by the Company under this Agreement, the Company may elect (a) to establish a segregated account in the amount of the repurchase price, such account to be turned over to the Participant or his or her successor in interest upon delivery of such Shares, and (b) immediately to take such action as is appropriate to transfer record title of such Shares from the Participant to the Company and to treat the Participant and such Shares in all respects as if delivery of such Shares had been made as required by this Agreement. The Participant hereby irrevocably grants the Company a power of attorney which shall be coupled with an interest for the purpose of effectuating the preceding sentence.

12.5 If the Company shall pay a stock dividend or declare a stock split on or with respect to any of its Common Stock, or otherwise distribute securities of the Company to the holders of its Common Stock, the number of shares of stock or other securities of the Company issued with respect to the shares then subject to the restrictions contained in this Agreement shall be added to the Shares subject to the Company’s rights to repurchase pursuant to this Agreement. If the Company shall distribute to its stockholders shares of stock of another corporation, the shares of stock of such other corporation, distributed with respect to the Shares then subject to the restrictions contained in this Agreement, shall be added to the Shares subject to the Company’s rights to repurchase pursuant to this Agreement.

12.6 If the outstanding shares of Common Stock of the Company shall be subdivided into a greater number of shares or combined into a smaller number of shares, or in the event of a reclassification of the outstanding shares of Common Stock of the Company, or if the Company shall be a party to a merger, consolidation or capital reorganization, there shall be substituted for the Shares then subject to the restrictions contained in this Agreement such amount and kind of securities as are issued in such subdivision, combination, reclassification, merger, consolidation or capital reorganization in respect of the Shares subject immediately prior thereto to the Company’s rights to repurchase pursuant to this Agreement.

12.7 The Company shall not be required to transfer any Shares on its books which shall have been sold, assigned or otherwise transferred in violation of this Agreement, or to treat as owner of such Shares, or to accord the right to vote as such owner or to pay dividends to, any person or organization to which any such Shares shall have been so sold, assigned or otherwise transferred, in violation of this Agreement.

12.8 The provisions of Sections 12.1, 12.2 and 12.3 shall terminate upon the effective date of the registration of the Shares pursuant to the Securities Exchange Act of 1934.

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12.9 The Participant agrees that in the event the Company proposes to offer for sale to the public any of its equity securities and such Participant is requested by the Company and any underwriter engaged by the Company in connection with such offering to sign an agreement restricting the sale or other transfer of Shares, then it will promptly sign such agreement and will not transfer, whether in privately negotiated transactions or to the public in open market transactions or otherwise, any Shares or other securities of the Company held by him or her during such period as is determined by the Company and the underwriters, not to exceed 180 days following the closing of the offering, plus such additional period of time as may be required to comply with NASD Rule 2711 or similar rules thereto (such period, the “Lock-Up Period”). Such agreement shall be in writing and in form and substance reasonably satisfactory to the Company and such underwriter and pursuant to customary and prevailing terms and conditions. Notwithstanding whether the Participant has signed such an agreement, the Company may impose stop-transfer instructions with respect to the Shares or other securities of the Company subject to the foregoing restrictions until the end of the Lock-Up Period.

12.10 The Participant acknowledges and agrees that neither the Company, its shareholders nor its directors and officers, has any duty or obligation to disclose to the Participant any material information regarding the business of the Company or affecting the value of the Shares before, at the time of, or following a termination of the service of the Participant by the Company, including, without limitation, any information concerning plans for the Company to make a public offering of its securities or to be acquired by or merged with or into another firm or entity.

12.11 All certificates representing the Shares to be issued to the Participant pursuant to this Agreement shall have endorsed thereon a legend substantially as follows: “The shares represented by this certificate are subject to restrictions set forth in a Stock Option Agreement dated ____________, 201__ with this Company, a copy of which Agreement is available for inspection at the offices of the Company or will be made available upon request.”

The Participant acknowledges that: (i) the Company is not by the Plan or this Option obligated to continue the Participant as an employee, director or Consultant of the Company or an Affiliate; (ii) the Plan is discretionary in nature and may be suspended or terminated by the Company at any time; (iii) the grant of the Option is a one-time benefit which does not create any contractual or other right to receive future grants of options, or benefits in lieu of options; (iv) all determinations with respect to any such future grants, including, but not limited to, the times when options shall be granted, the number of shares subject to each option, the option price, and the time or times when each option shall be exercisable, will be at the sole discretion of the Company; (v) the Participant’s participation in the Plan is voluntary; (vi) the value of the Option is an extraordinary item of compensation which is outside the scope of the Participant’s employment or consulting contract, if any; and (vii) the Option is not part of normal or expected compensation for purposes of calculating any severance, resignation, redundancy, end of service payments, bonuses, long-service awards, pension or retirement benefits or similar payments.

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If this Option is designated in the Stock Option Grant Notice as an ISO so that the Participant (or the Participant’s Survivors) may qualify for the favorable tax treatment provided to holders of Options that meet the standards of Section 422 of the Code then any provision of this Agreement or the Plan which conflicts with the Code so that this Option would not be deemed an ISO is null and void and any ambiguities shall be resolved so that the Option qualifies as an ISO. The Participant should consult with the Participant’s own tax advisors regarding the tax effects of the Option and the requirements necessary to obtain favorable tax treatment under Section 422 of the Code, including, but not limited to, holding period requirements.

Notwithstanding the foregoing, to the extent that the Option is designated in the Stock Option Grant Notice as an ISO and is not deemed to be an ISO pursuant to Section 422(d) of the Code because the aggregate Fair Market Value (determined as of the Date of Option Grant) of any of the Shares with respect to which this ISO is granted becomes exercisable for the first time during any calendar year in excess of $100,000, the portion of the Option representing such excess value shall be treated as a Non-Qualified Option and the Participant shall be deemed to have taxable income measured by the difference between the then Fair Market Value of the Shares received upon exercise and the price paid for such Shares pursuant to this Agreement.

Neither the Company nor any Affiliate shall have any liability to the Participant, or any other party, if the Option (or any part thereof) that is intended to be an ISO is not an ISO or for any action taken by the Administrator, including without limitation the conversion of an ISO to a Non-Qualified Option.

If this Option is designated in the Stock Option Grant Notice as an ISO then the Participant agrees to notify the Company in writing immediately after the Participant makes a Disqualifying Disposition of any of the Shares acquired pursuant to the exercise of the ISO. A Disqualifying Disposition is defined in Section 424(c) of the Code and includes any disposition (including any sale) of such Shares before the later of (a) two years after the date the Participant was granted the ISO or (b) one year after the date the Participant acquired Shares by exercising the ISO, except as otherwise provided in Section 424(c) of the Code. If the Participant has died before the Shares are sold, these holding period requirements do not apply and no Disqualifying Disposition can occur thereafter.

Any notices required or permitted by the terms of this Agreement or the Plan shall be given by recognized courier service, facsimile, registered or certified mail, return receipt requested, addressed as follows:

If to the Company:

X4 Pharmaceuticals, Inc.

One Broadway, 14^th Floor

Cambridge, MA 02142

Attention: President

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If to the Participant at the address set forth on the Stock Option Grant Notice or to such other address or addresses of which notice in the same manner has previously been given. Any such notice shall be deemed to have been given upon the earlier of receipt, one business day following delivery to a recognized courier service or three business days following mailing by registered or certified mail.

This Agreement shall be governed by and construed in accordance with the laws of the State of Delaware, without giving effect to the conflict of law principles thereof. For the purpose of litigating any dispute that arises under this Agreement, the parties hereby consent to exclusive jurisdiction in Massachusetts and agree that such litigation shall be conducted in the state courts of Middlesex County, Massachusetts or the federal courts of the United States for the District of Massachusetts.

Subject to the provisions of the Plan and the other provisions hereof, this Agreement shall be for the benefit of and shall be binding upon the heirs, executors, administrators, successors and assigns of the parties hereto.

This Agreement, together with the Plan, embodies the entire agreement and understanding between the parties hereto with respect to the subject matter hereof and supersedes all prior oral or written agreements and understandings relating to the subject matter hereof. No statement, representation, warranty, covenant or agreement not expressly set forth in this Agreement shall affect or be used to interpret, change or restrict, the express terms and provisions of this Agreement, provided, however, in any event, this Agreement shall be subject to and governed by the Plan.

The terms and provisions of this Agreement may be modified or amended as provided in the Plan.

Except as provided in the Plan, the terms and provisions of this Agreement may be waived, or consent for the departure therefrom granted, only by written document executed by the party entitled to the benefits of such terms or provisions. No such waiver or consent shall be deemed to be or shall constitute a waiver or consent with respect to any other terms or provisions of this Agreement, whether or not similar. Each such waiver or consent shall be effective only in the specific instance and for the purpose for which it was given, and shall not constitute a continuing waiver or consent.

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By entering into this Agreement, the Participant: (i) authorizes the Company and each Affiliate, and any agent of the Company or any Affiliate administering the Plan or providing Plan recordkeeping services, to disclose to the Company or any of its Affiliates such information and data as the Company or any such Affiliate shall request in order to facilitate the grant of options and the administration of the Plan; (ii) waives any data privacy rights he or she may have with respect to such information; and (iii) authorizes the Company and each Affiliate to store and transmit such information in electronic form.

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Exhibit A

NOTICE OF EXERCISE OF STOCK OPTION

[Form for Unregistered Shares]

To: X4 Pharmaceuticals, Inc.

Ladies and Gentlemen:

I hereby exercise my Stock Option to purchase ______ shares (the “Shares”) of the common stock, $0.001 par value, of X4 Pharmaceuticals, Inc. (the “Company”), at the exercise price of $_____ per share, pursuant to and subject to the terms of that certain Stock Option Agreement between the undersigned and the Company dated _________, 201_.

I am aware that the Shares have not been registered under the Securities Act of 1933, as amended (the “1933 Act”), or any state securities laws. I understand that the reliance by the Company on exemptions under the 1933 Act is predicated in part upon the truth and accuracy of the statements by me in this Notice of Exercise.

I hereby represent and warrant that (1) I have been furnished with all information which I deem necessary to evaluate the merits and risks of the purchase of the Shares; (2) I have had the opportunity to ask questions concerning the Shares and the Company and all questions posed have been answered to my satisfaction; (3) I have been given the opportunity to obtain any additional information I deem necessary to verify the accuracy of any information obtained concerning the Shares and the Company; and (4) I have such knowledge and experience in financial and business matters that I am able to evaluate the merits and risks of purchasing the Shares and to make an informed investment decision relating thereto.

I hereby represent and warrant that I am purchasing the Shares for my own personal account for investment and not with a view to the sale or distribution of all or any part of the Shares.

I understand that because the Shares have not been registered under the 1933 Act, I must continue to bear the economic risk of the investment for an indefinite time and the Shares cannot be sold unless the Shares are subsequently registered under applicable federal and state securities laws or an exemption from such registration requirements is available.

I agree that I will in no event sell or distribute or otherwise dispose of all or any part of the Shares unless (1) there is an effective registration statement under the 1933 Act and applicable state securities laws covering any such transaction involving the Shares or (2) the Company receives an opinion of my legal counsel (concurred in by legal counsel for the Company) stating that such transaction is exempt from registration or the Company otherwise satisfies itself that such transaction is exempt from registration.

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I consent to the placing of a legend on my certificate for the Shares stating that the Shares have not been registered and setting forth the restriction on transfer contemplated hereby and to the placing of a stop transfer order on the books of the Company and with any transfer agents against the Shares until the Shares may be legally resold or distributed without restriction.

I understand that at the present time Rule 144 of the Securities and Exchange Commission (the “SEC”) may not be relied on for the resale or distribution of the Shares by me. I understand that the Company has no obligation to me to register the sale of the Shares with the SEC and has not represented to me that it will register the sale of the Shares.

I understand the terms and restrictions on the right to dispose of the Shares set forth in the 2015 Employee, Director and Consultant Equity Incentive Plan and the Stock Option Agreement, both of which I have carefully reviewed. I consent to the placing of a legend on my certificate for the Shares referring to such restriction and the placing of stop transfer orders until the Shares may be transferred in accordance with the terms of such restrictions.

I have considered the Federal, state and local income tax implications of the exercise of my Option and the purchase and subsequent sale of the Shares.

I am paying the option exercise price for the Shares as follows:

Please issue the Shares (check one):

☐ to me; or

☐ to me and                                  , as joint tenants with right of survivorship

and mail the certificate to me at the following address:

My mailing address for shareholder communications, if different from the address listed above is:

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Exhibit 10.2

X4 PHARMACEUTICALS, INC.

DIRECTOR COMPENSATION POLICY

(Last modified: March 13, 2019)

The Board of Directors (the “Board”) of X4 Pharmaceuticals, Inc. (the “Company”), has approved the following Director Compensation Policy under which the Company’s non-employee directors shall receive the following compensation for their service as members of the Board of Directors.

Director Compensation

Our goal is to provide compensation for our non-employee directors in a manner that enables us to attract and retain outstanding director candidates and reflects the substantial time commitment necessary to oversee the Company’s affairs. We also seek to align the interests of our directors and our stockholders and we have chosen to do so by compensating our non-employee directors with a mix of cash and equity-based compensation.

Cash Compensation

The fees that will be paid to our non-employee directors for service on the Board, and for service on each committee of the Board on which the director is then a member, and the fees that will be paid to the chairperson of the Board, if one is then appointed, and the chairperson of each committee of the Board will be as follows:

The foregoing fees will be payable in arrears in four equal quarterly installments on the last day of each quarter, provided that the amount of such payment will be prorated for any portion of such quarter that the director is not serving on our Board, on such committee or in such position, and no fee shall be payable in respect of any period prior to the completion of our initial public offering.

Equity Compensation

Initial Grants. Upon initial election to our Board, such non-employee director will be granted, automatically and without the need for any further action by the Board, an initial equity award of an option to purchase 6,854 shares of our common stock. The initial award shall have a term of ten years from the date of the award, and shall vest and become exercisable as to 33.3333% of the shares underlying such award on the 12-month anniversary of the date of the award, with the remainder vesting in equal monthly installments of 2.7777% of the shares underlying the initial award until the 36-month anniversary of the date of the award, subject the director’s continued service as a director, employee or consultant through each applicable vesting date. The vesting shall accelerate as to 100% of the shares upon a change in control of the Company. The exercise price shall be the closing price of our common stock on the date of grant.

Annual Grants. Each non-employee director who has served as a member of our Board for at least six months prior to the date of our annual meeting of stockholders for a particular year will be granted, automatically and without the need for any further action by the Board, an equity award on the date of our annual meeting of stockholders for such year of an option to purchase 3,427 shares of our common stock. The annual award shall have a term of ten years from the date of the award, and shall vest and become exercisable as to 8.3333% of the shares underlying such award on the one-month anniversary of the date of the award, with the remainder vesting in equal monthly installments of 8.3333% of the shares underlying the annual award until the twelve-month anniversary of the date of the award (or, if earlier, the date of the next annual meeting of stockholders following the date of grant of the option), subject to the director’s continued service as a director, employee or consultant through each applicable vesting date. The vesting shall accelerate as to 100% of the shares upon a change in control of the Company. The exercise price shall be the closing price of our common stock on the date of grant.

The foregoing share amounts shall be automatically adjusted in the event of any stock split, reverse stock split, stock dividend, recapitalization, combination of shares, reclassification of shares, spin-off or other similar change in capitalization or event effecting our common stock, or any distribution to holders of our common stock other than an ordinary cash dividend.

The initial awards and the annual awards shall be subject to the terms and conditions of our 2017 Stock Incentive Plan, or any successor plan, and the terms of the option agreements entered into with each director in connection with such awards.

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Expenses

Upon presentation of documentation of such expenses reasonably satisfactory to the Company, each non-employee director shall be reimbursed for his or her reasonable out-of-pocket business expenses incurred in connection with attending meetings of the Board and committees thereof or in connection with other business related to the Board, and each non-employee director shall also be reimbursed for his or her reasonable out-of-pocket business expenses authorized by the Board or a committee of the Board that are incurred in connection with attendance at various conferences or meetings with management of the Company, in accordance with the Company’s travel policy, as it may be in effect from time to time.

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Exhibit 10.3

AMENDED AND RESTATED EXECUTIVE EMPLOYMENT AGREEMENT

This Amended and Restated Executive Employment Agreement (the “Agreement”), by and between X4 Pharmaceuticals, Inc. (“Company”) and Paula Ragan, Ph.D (“Executive”), is made and entered into as of the date the Agreement is approved by the Company’s Board of Directors or an appropriate committee thereof (the “Effective Date”).

WHEREAS, Company entered into that certain Agreement and Plan of Merger, dated as of November 26, 2018 (as amended, the “Merger Agreement”), with Arsanis, Inc. (“Arsanis”) and Artemis AC Corp. (“Merger Sub”) whereby Merger Sub shall merge with and into Company and Company shall become a wholly-owned subsidiary of Arsanis (the “Arsanis Merger”);

WHEREAS, Company wishes to continue employing Executive to serve as its Chief Executive Officer contingent on the successful consummation of the Arsanis Merger;

WHEREAS, Executive represents that Executive possesses the necessary skills to perform the duties of this position and that Executive has no obligation to any other person or entity which would prevent, limit or interfere with Executive’s ability to do so; and

WHEREAS, Executive and Company desire to enter into this Amended and Restated Executive Employment Agreement to assure the harmonious performance of the affairs of Company.

NOW, THEREFORE, in consideration of the mutual promises, terms, provisions, and conditions contained herein, the parties agree as follows:

1. Title and Duties. Contingent on the successful consummation of the Arsanis Merger, and subject to the terms and conditions of this Agreement, Executive’s position with Company shall be Chief Executive Officer (“CEO”), reporting to Company’s Board of Directors (the “Board”). Executive accepts such employment upon the terms and conditions set forth herein, and agrees to perform to the best of Executive’s ability the duties normally associated with such position and as reasonably determined by the Board in its sole discretion. While serving as CEO hereunder, Executive shall devote all of Executive’s business time and energies to the business and affairs of Company, provided that nothing contained in this Section 1 shall prevent or limit: (a) Executive’s right to manage Executive’s personal investments on Executive’s own personal time, including, without limitation the right to make passive investments in the securities of (i) any entity which Executive does not control, directly or indirectly, and which does not compete with Company, or (ii) any publicly held entity, so long as Executive’s aggregate direct and indirect interest does not exceed two percent (2%) of the issued and outstanding securities of any class of securities of such publicly held entity; and (b) Executive’s participation in civic and charitable activities, including as a member of a board of a civic or charitable organization, so long as such activities do not interfere with Executive’s performance of Executive’s duties hereunder.

2. Term; Termination.

(a) Term. Subject to the terms hereof and contingent on the successful consummation of the Arsanis Merger, Executive’s employment hereunder shall become effective on March 13, 2019 (the “Commencement Date”) and shall continue until terminated hereunder by either party (such term of employment shall be referred to herein as the “Term”).

(b) Termination by Company. Notwithstanding anything else contained in this Agreement, Company may terminate Executive’s employment hereunder as follows:

(i) For Cause. Company may terminate Executive’s employment for Cause (as defined below) by written notice by Company to Executive that Executive’s employment is being terminated for Cause, which termination shall be effective on the date of such notice or such later date as specified in writing by Company, provided that if Executive has cured the circumstances giving rise to Cause (as such cure right may be applicable pursuant to the terms and conditions set forth below) then such termination shall not be effective.

(ii) Without Cause. Company may terminate Executive’s employment without Cause, by written notice by Company to Executive that Executive’s employment is being terminated without Cause, which termination shall be effective ninety (90) days after the date of such notice or such later date as specified in writing by Company.

For the purposes of this Agreement, “Cause” shall mean: (A) fraud, embezzlement, or illegal misconduct in connection with Executive’s duties under this Agreement; (B) conviction of a felony involving fraud, dishonesty or breach of trust; (C) willful misconduct or gross negligence in the performance of the duties delegated to Executive; (D) material breach of this Agreement; or (E) material breach of any non-competition, non-solicitation, non-disclosure, and intellectual property assignment agreement between Executive and Company; provided that “Cause” shall not be deemed to have occurred pursuant to subsections (C) or (D) hereof unless Executive has first received written notice specifying in reasonable detail the particulars of such ground and that Company intends to terminate Executive’s employment hereunder for such ground, and if such ground is curable, Executive has failed to cure such ground within a period of thirty (30) days from the date of her receipt of such notice.

(c) Termination by Executive. Notwithstanding anything else contained in this Agreement, Executive may terminate Executive’s employment hereunder as follows:

(i) For Good Reason. Executive may terminate Executive’s employment for Good Reason (as defined below) by written notice by Executive to Company that Executive is terminating Executive’s employment for Good Reason, which termination shall be effective thirty (30) days after the date of such notice; provided that if Company has cured the circumstances giving rise to Good Reason then such termination shall not be effective; or

(ii) Without Good Reason. Executive may terminate Executive’s employment without Good Reason by written notice by Executive to Company that Executive is terminating Executive’s employment, which termination shall be effective ninety (90) days after the date of such notice.

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For the purposes of this Agreement, “Good Reason” shall mean: (A) a material reduction in Executive’s then-current Base Salary; (B) a material diminution in Executive’s authority, duties, or responsibilities; (C) a material change in the geographic location at which the Executive provides services to the Company outside of a fifty (50) mile radius from the then-current location; or (D) any action or inaction by Company that constitutes a material breach of this Agreement; provided that “Good Reason” shall not be deemed to have occurred unless: (1) Executive provides Company with written notice that Executive intends to terminate Executive’s employment hereunder for one of the grounds set forth above within thirty (30) days of such ground first occurring, (2) if such ground is capable of being cured, Company has failed to cure such ground within a period of thirty (30) days from the date of such written notice, and (3) Executive terminates Executive’s employment within seventy five (75) days from the date that Good Reason first occurs. For purposes of clarification, the above-listed conditions shall apply separately to each occurrence of Good Reason and failure to adhere to such conditions in the event of Good Reason shall not disqualify Executive from asserting Good Reason for any subsequent occurrence of Good Reason.

(d) Termination Due to Disability. Notwithstanding anything else contained in this Agreement, Company may terminate Executive’s employment due to Executive’s Disability (as defined below) by written notice to Executive that Executive’s employment is being terminated as a result of Executive’s Disability, which termination shall be effective on the date of such notice or such later date as specified in writing by Company. For the purposes of this Agreement, “Disability” shall mean Executive’s incapacity or inability to perform Executive’s duties and responsibilities as contemplated herein for one hundred twenty (120) days or more within any one (1) year period (cumulative or consecutive), because Executive’s physical or mental health has become so impaired as to make it impossible or impractical for Executive to perform the duties and responsibilities contemplated hereunder. Determination of Executive’s physical or mental health shall be determined by the Board after consultation with a medical expert appointed by mutual agreement between Company and Executive who has examined Executive. Executive hereby consents to such examination and consultation regarding Executive’s health and ability to perform as aforesaid.

3. Compensation.

(a) Base Salary. While Executive is employed hereunder, Executive shall earn a base salary at the annual rate approved by the Board or an appropriate committee thereof (as may be changed from time-to-time, the “Base Salary”). The Base Salary shall be payable in substantially equal periodic installments, at least on a monthly basis, in accordance with Company’s payroll practices as in effect from time to time. Company shall deduct from each such installment all amounts required to be deducted or withheld under applicable law or under any employee benefit plan in which Executive participates.

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(b) Annual Bonus. Executive shall be eligible to receive an annual performance bonus (the “Annual Bonus”) for all years in which Executive is employed by Company hereunder. The Annual Bonus potential shall be in an amount approved by the Board or an appropriate committee thereof, but under no circumstances shall the Annual Bonus potential be less than twenty-five percent (25%) of Executive’s then Base Salary (provided that, as stated below, the amount of any Annual Bonus remains in the Board’s discretion). The amount of the Annual Bonus shall be based on factors such as Executive’s work performance, Company’s financial performance, Company’s business forecasts, Company’s determination of Executive’s achievement of milestones for the applicable year, and economic conditions generally. The actual amount of the Annual Bonus shall be determined by the Board in its sole discretion. The Annual Bonus shall be paid to Executive in no event later than March 15th of the calendar year immediately following the calendar year to which it pertains. Executive must be employed by Company at the time that the Annual Bonus is paid in order to be eligible for, and to be deemed as having earned, such Annual Bonus. Company shall deduct from the Annual Bonus all amounts required to be deducted or withheld under applicable law or under any employee benefit plan in which Executive participates.

(c) Fringe Benefits. Executive shall be entitled to participate in all benefit/welfare plans and fringe benefits provided to employees at the same level as Executive. Executive understands that, except when prohibited by applicable law, Company’s benefit plans and fringe benefits may be amended by Company from time to time in its sole discretion.

(d) Vacation. Consistent with Company’s current policy and given Executive’s tenure with Company, Executive shall be eligible to accrue up to twenty (20) days of vacation per year, to be scheduled to minimize disruption to Company’s operations. Executive’s vacation use, accrual and carryover shall be subject to the terms and conditions of Company’s vacation policy in effect from time to time.

(e) Reimbursement of Expenses. Company shall reimburse Executive for all ordinary and reasonable out-of-pocket business expenses incurred by Executive in furtherance of Company’s business in accordance with Company’s policies with respect thereto as in effect from time to time. Executive must submit any request for reimbursement no later than ninety (90) days following the date that such business expense is incurred. All reimbursements provided under this Agreement shall be made or provided in accordance with the requirements of Section 409A (“Section 409A”) of the Code and the rules and regulations thereunder, including, where applicable, the requirement that (i) any reimbursement is for expenses incurred during Executive’s lifetime (or during a shorter period of time specified in this Agreement); (ii) the amount of expenses eligible for reimbursement during a calendar year may not affect the expenses eligible for reimbursement in any other calendar year; (iii) the reimbursement of an eligible expense shall be made no later than the last day of the calendar year following the year in which the expense is incurred; and (iv) the right to reimbursement or in kind benefits is not subject to liquidation or exchange for another benefit.

(f) Indemnification. Executive shall be eligible for coverage under Company Directors’ and Officers’ (“D&O”) insurance policies to the same extent and in the same manner to which Company’s similarly situated executives are entitled to coverage under Company D&O insurance policies, subject to the terms and conditions of any such Company D&O insurance policies.

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4. Termination Payments; Severance Benefit.

(a) Payment of Accrued Obligations. Regardless of the reason for any employment termination hereunder, Company shall pay to Executive: (i) the portion of Executive’s Base Salary that has accrued prior to any termination of Executive’s employment and has not yet been paid; (ii) the portion of Executive’s vacation days that have accrued prior to any termination of Executive’s employment and has not yet been used; and (iii) the amount of any expenses properly incurred by Executive on behalf of Company prior to any such termination and has not yet been reimbursed (together, the “Accrued Obligations”) promptly following the effective date of termination, and otherwise within any timeframe required by law. Executive’s entitlement to other compensation or benefits under any Company plan or policy shall be governed by and determined in accordance with the terms of such plan or policy, except as otherwise specified in this Agreement. In the event of Company’s termination of Executive’s employment for Cause or Executive’s termination of Executive’s employment without Good Reason, Executive shall be eligible for the Accrued Obligations and shall not be eligible for any severance or severance-type payments, other than as expressly set forth herein.

(b) Severance in the Event of Termination Without Cause or Resignation for Good Reason. Subject to the terms and conditions of Section 4(d), in the event that Executive’s employment hereunder is terminated by Company without Cause or terminated by Executive for Good Reason, then, in addition to the Accrued Obligations:

(i) Company shall pay Executive an amount equal to continuation of Executive’s monthly Base Salary for a twelve (12) month period, with such payments to be made in accordance with Company’s normal payroll practices and schedules, less all customary and required taxes and employment-related deductions.

(ii) Company shall pay Executive a pro-rata portion of Executive’s at-target Annual Bonus for the calendar year in which the termination occurs based on the period worked by Executive during such calendar year prior to termination, with such payment to be made in on one lump sum in accordance with Company’s normal payroll practices and schedules, less all customary and required taxes and employment-related deductions.

(iii) In the event that Executive is eligible for coverage under a Company health insurance plan and Executive has elected to have coverage thereunder and was covered thereunder prior to termination, and in the event that Executive chooses to exercise Executive’s right under the Consolidated Omnibus Budget Reconciliation Act of 1985 (“COBRA”) to continue Executive’s participation in such plan, Company shall pay its normal share of the costs for such coverage for a period of up to twelve (12) months from termination, to the same extent that such insurance is provided to persons then currently employed by Company. Company shall deduct from each of the installments due under Section 4(b)(i) the portion of the monthly premium due from Executive in accordance with the terms of such coverage. Notwithstanding any other provision of this Agreement, this obligation shall cease on the date Executive becomes eligible to receive health insurance benefits through any other employer, and Executive agrees to provide Company with written notice immediately upon becoming eligible for such benefits. Executive’s acceptance of any payment on Executive’s behalf or coverage provided hereunder shall be an express representation to Company that Executive has no such eligibility.

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(iv) Executive shall become vested in the additional number of outstanding time-based equity awards granted to Executive by Company that would have otherwise vested had Executive remained in employment for an additional twelve (12) months after the termination date.

Subsections (i), (ii), (iii) and (iv) are referred to as the Severance Benefit. The Severance Benefit is expressly subject to the conditions described above and in Section 4(d) below. Any payment or benefit made as part of such Severance Benefit shall be paid less all customary and required taxes and employment-related deductions.

(c) Accelerated Vesting in Event of Termination without Cause or Resignation for Good Reason Following Change of Control. Subject to the terms and conditions of Section 4(d), in the event that a Change of Control (as defined below) occurs and within a period of one (1) year following the Change of Control the Company terminates Executive’s employment without Cause or Executive resigns for Good Reason, then Executive automatically shall become vested in one hundred percent (100%) of outstanding time-based equity awards granted to Executive by Company. The above-described vesting is expressly subject to the conditions described in Section 4(d), and shall be provided less all customary and required taxes and employment-related deductions. For purposes of this section, a “Change of Control” shall mean the occurrence of any of the following events: (i) Ownership. Any “Person” (as such term is used in Sections 13(d) and 14(d) of the Securities Exchange Act of 1934, as amended) becomes the “Beneficial Owner” (as defined in Rule 13d-3 under said Act), directly or indirectly, of securities of Company representing fifty percent (50%) or more of the total voting power represented by Company’s then outstanding voting securities (excluding for this purpose any such voting securities held by Company, or any affiliate, parent or subsidiary of Company, or by any employee benefit plan of Company) pursuant to a transaction or a series of related transactions which the Board does not approve; or (ii) Merger/Sale of Assets. (A) A merger or consolidation of Company whether or not approved by the Board, other than a merger or consolidation which would result in the voting securities of Company outstanding immediately prior thereto continuing to represent (either by remaining outstanding or by being converted into voting securities of the surviving entity or the parent of such corporation) at least fifty percent (50%) of the total voting power represented by the voting securities of Company or such surviving entity or parent of such corporation, as the case may be, outstanding immediately after such merger or consolidation; or (B) the sale or disposition by Company of all or substantially all of Company’s assets.

(d) Conditions. Company shall not be obligated to provide Executive any payment, benefit and/or vesting described in Section 4(b) or Section 4(c) unless and until Executive has executed without revocation a separation agreement in a form acceptable to Company, which must be signed by Executive, returned to Company and be enforceable and irrevocable no later than sixty (60) days following Executive’s separation from service (the “Review Period”), and which shall include, at a minimum, the provision of separation pay and benefits due from Company to Executive as applicable, a complete general release of claims against Company and its affiliated entities and each of their officers, directors and employees, and terms relating to non-disparagement, non-competition, confidentiality, cooperation and the like similar in scope, duration and substance to those terms set forth in the agreement described in Section 5 below. If

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Executive executes and does not revoke such agreement within the Review Period, then provision of payments, benefits and/or vesting shall commence on the first (1st) day following the Review Period, provided that if the last day of the Review Period occurs in the calendar year following the year of termination, then the payment shall not commence until January 2 of such subsequent calendar year, and further provided that, as applied to Section 4(b)(i), (ii) and (iii) as applicable, the first payments/benefits shall include in a lump sum all amounts that were otherwise payable to Executive from the date of Executive’s separation from service occurred through such first payment.

(e) COBRA. If the payment of any COBRA or health insurance premiums by Company on behalf of Executive as described herein would otherwise violate any applicable nondiscrimination rules or cause the reimbursement of claims to be taxable under the Patient Protection and Affordable Care Act of 2010, together with the Health Care and Education Reconciliation Act of 2010 (collectively, the “Act”) or Section 105(h) of the Code, the COBRA premiums paid by Company shall be treated as taxable payments (subject to customary and required taxes and employment-related deductions) and be subject to imputed income tax treatment to the extent necessary to eliminate any discriminatory treatment or taxation under the Act or Section 105(h) of the Code. If Company determines in its sole discretion that it cannot provide the COBRA benefits described herein under Company’s health insurance plan without potentially violating applicable law (including, without limitation, Section 2716 of the Public Health Service Act), Company shall in lieu thereof provide to Executive a taxable lump-sum payment in an amount equal to the sum of the monthly (or then remaining) COBRA premiums that Executive would be required to pay to maintain Executive’s group health insurance coverage in effect on the separation date for the remaining portion of the period for which Executive shall receive the payments described in Sections 4(b) or 4(c) above.

(f) No Other Payments or Benefits Owing. The payments and benefits set forth in this Section 4 shall be the sole amounts owing to Executive upon termination of Executive’s employment for the reasons set forth above and Executive shall not be eligible for any other payments or other forms of compensation or benefits. The payments and benefits set forth in this Section shall be the sole remedy, if any, available to Executive in the event that Executive brings any claim against Company relating to the termination of Executive’s employment under this Agreement.

(g) No Mitigation of Damages Offset. Except as otherwise may be expressly provided herein, Executive shall not be required to mitigate any amounts due or provided her under this Agreement by seeking other employment or otherwise. Any payments made by Company to Executive after the termination of employment shall not be reduced by any compensation Executive receives from any subsequent employment or source.

5. Non-Competition, Non-Solicitation, Non-Disclosure Agreement. Executive has signed and agrees to continue to abide by Company’s Non-Competition, Non-Solicitation, Non-Disclosure, and Intellectual Property Agreement.

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6. Code Sections 409A and 280G.

(a) In the event that the payments or benefits set forth in Section 4 constitute “non-qualified deferred compensation” subject to Section 409A, then the following conditions apply to such payments or benefits:

(i) Any termination of Executive’s employment triggering payment of benefits under Section 4 must constitute a “separation from service” under Section 409A(a)(2)(A)(i) of the Code and Treas. Reg. §1.409A-1(h) before distribution of such benefits can commence. To the extent that the termination of Executive’s employment does not constitute a separation of service under Section 409A(a)(2)(A)(i) of the Code and Treas. Reg. §1.409A-1(h) (as the result of further services that are reasonably anticipated to be provided by Executive to Company at the time Executive’s employment terminates), any such payments under Section 4 that constitute deferred compensation under Section 409A shall be delayed until after the date of a subsequent event constituting a separation of service under Section 409A(a)(2)(A)(i) of the Code and Treas. Reg. §1.409A-1(h). For purposes of clarification, this Section 6(a) shall not cause any forfeiture of benefits on Executive’s part, but shall only act as a delay until such time as a “separation from service” occurs.

(ii) Notwithstanding any other provision with respect to the timing of payments under Section 4 if, at the time of Executive’s termination, Executive is deemed to be a “specified employee” of Company (within the meaning of Section 409A(a)(2)(B)(i) of the Code), then limited only to the extent necessary to comply with the requirements of Section 409A, any payments to which Executive may become entitled under Section 4 which are subject to Section 409A (and not otherwise exempt from its application) shall be withheld until the first (1st) business day of the seventh (7th) month following the termination of Executive’s employment, at which time Executive shall be paid an aggregate amount equal to the accumulated, but unpaid, payments otherwise due to Executive under the terms of Section 4.

(b) It is intended that each installment of the payments and benefits provided under Section 4 shall be treated as a separate “payment” for purposes of Section 409A. Neither Company nor Executive shall have the right to accelerate or defer the delivery of any such payments or benefits except to the extent specifically permitted or required by Section 409A.

(c) Notwithstanding any other provision of this Agreement to the contrary, this Agreement shall be interpreted and at all times administered in a manner that avoids the inclusion of compensation in income under Section 409A, or the payment of increased taxes, excise taxes or other penalties under Section 409A. The parties intend this Agreement to be in compliance with Section 409A. Executive acknowledges and agrees that Company does not guarantee the tax treatment or tax consequences associated with any payment or benefit arising under this Agreement, including but not limited to consequences related to Section 409A.

(d) If any payment or benefit Executive would receive under this Agreement, when combined with any other payment or benefit Executive receives pursuant to a Change of Control (for purposes of this section, a “Payment”) would: (i) constitute a “parachute payment” within the meaning of Section 280G the Code; and (ii) but for this sentence, be subject to the excise tax imposed by Section 4999 of the Code (the “Excise Tax”), then such Payment shall be either: (A) the full amount of such Payment; or (B) such lesser amount (with cash payments being reduced

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before stock option compensation) as would result in no portion of the Payment being subject to the Excise Tax, whichever of the foregoing amounts, taking into account the applicable federal, state and local employments taxes, income taxes, and the Excise Tax, results in Executive’s receipt, on an after-tax basis, of the greater amount of the Payment notwithstanding that all or some portion of the Payment may be subject to the Excise Tax.

7. General.

(a) Notices. Except as otherwise specifically provided herein, any notice required or permitted by this Agreement shall be in writing and shall be delivered as follows with notice deemed given as indicated: (i) by personal delivery when delivered personally; (ii) by overnight courier upon written verification of receipt; (iii) by facsimile transmission upon acknowledgment of receipt of electronic transmission; or (iv) by certified or registered mail, return receipt requested, upon verification of receipt.

Notices to Executive shall be sent to the last known address in Company’s records or such other address as Executive may specify in writing.

Notices to Company shall be sent to:

X4 Pharmaceuticals, Inc.

955 Massachusetts Ave., 4th Floor

Cambridge, MA 02139

Attention: Chair, Board of Directors

with a copy to:

Mintz, Levin, Cohn, Ferris, Glovsky & Popeo, P.C.

One Financial Center

Boston, MA, 02111

Attn: John J. Cheney, Esq.

(b) Modifications and Amendments. The terms and provisions of this Agreement may be modified or amended only by written agreement executed by the parties hereto.

(c) Waivers and Consents. The terms and provisions of this Agreement may be waived, or consent for the departure therefrom granted, only by written document executed by the party entitled to the benefits of such terms or provisions. No such waiver or consent shall be deemed to be or shall constitute a waiver or consent with respect to any other terms or provisions of this Agreement, whether or not similar. Each such waiver or consent shall be effective only in the specific instance and for the purpose for which it was given, and shall not constitute a continuing waiver or consent.

(d) Assignment. Company may assign its rights and obligations hereunder to any person or entity that succeeds to all or substantially all of Company’s business or that aspect of Company’s business in which Executive is principally involved. Executive may not assign Executive’s rights and obligations under this Agreement without the prior written consent of Company.

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(e) Governing Law; Jury Waiver. This Agreement and the rights and obligations of the parties hereunder shall be construed in accordance with and governed by the law of Massachusetts without giving effect to the conflict of law principles thereof. Any legal action or proceeding with respect to this Agreement shall be brought in the courts of the Commonwealth of Massachusetts or the United States of America for the District of Massachusetts. By execution and delivery of this Agreement, each of the parties hereto accepts for itself and in respect of its property, generally and unconditionally, the exclusive jurisdiction of the aforesaid courts. ANY ACTION, DEMAND, CLAIM OR COUNTERCLAIM ARISING UNDER OR RELATING TO THIS AGREEMENT SHALL BE RESOLVED BY A JUDGE ALONE AND EACH OF COMPANY AND EXECUTIVE WAIVES ANY RIGHT TO A JURY TRIAL THEREOF.

(f) Headings and Captions. The headings and captions of the various subdivisions of this Agreement are for convenience of reference only and shall in no way modify or affect the meaning or construction of any of the terms or provisions hereof.

(g) Entire Agreement. This Agreement, together with the other agreements specifically referenced herein, embodies the entire agreement and understanding between the parties hereto with respect to the subject matter hereof and supersedes all prior oral or written agreements and understandings relating to the subject matter hereof. No statement, representation, warranty, covenant or agreement of any kind not expressly set forth in this Agreement shall affect, or be used to interpret, change or restrict, the express terms and provisions of this Agreement.

(h) Counterparts. This Agreement may be executed in two or more counterparts, and by different parties hereto on separate counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument. For all purposes a signature by fax shall be treated as an original.

[Signature Page to Follow]

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IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of the date first written above.

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Exhibit 10.4

AMENDED AND RESTATED EXECUTIVE EMPLOYMENT AGREEMENT

This Amended and Restated Executive Employment Agreement (the “Agreement”), by and between X4 Pharmaceuticals, Inc. (“Company”) and Adam S. Mostafa (“Executive”), is made and entered into as of the date the Agreement is approved by the Company’s Board of Directors (the “Board”) or an appropriate committee thereof (the “Effective Date”).

WHEREAS, Company entered into that certain Agreement and Plan of Merger, dated as of November 26, 2018 (as amended, the “Merger Agreement”), with Arsanis, Inc. (“Arsanis”) and Artemis AC Corp. (“Merger Sub”) whereby Merger Sub shall merge with and into Company and Company shall become a wholly-owned subsidiary of Arsanis (the “Arsanis Merger”);

WHEREAS, Company wishes to continue employing Executive to serve as its Chief Financial Officer contingent on the successful consummation of the Arsanis Merger;

WHEREAS, Executive represents that Executive possesses the necessary skills to perform the duties of this position and that Executive has no obligation to any other person or entity which would prevent, limit or interfere with Executive’s ability to do so; and

WHEREAS, Executive and Company desire to enter into this Amended and Restated Executive Employment Agreement to assure the harmonious performance of the affairs of Company.

NOW, THEREFORE, in consideration of the mutual promises, terms, provisions, and conditions contained herein, the parties agree as follows:

1. Title and Duties. Contingent on the successful consummation of the Arsanis Merger, and subject to the terms and conditions of this Agreement, Executive’s position with Company shall be Chief Financial Officer (“CFO”), reporting to Company’s Chief Executive Officer (“CEO”) or the CEO’s designee. Executive accepts such employment upon the terms and conditions set forth herein, and agrees to perform to the best of Executive’s ability the duties normally associated with such position and as reasonably determined by Company in its sole discretion. While serving as CFO hereunder, Executive shall devote all of Executive’s business time and energies to the business and affairs of Company, provided that nothing contained in this Section 1 shall prevent or limit: (a) Executive’s right to manage Executive’s personal investments on Executive’s own personal time, including, without limitation the right to make passive investments in the securities of (i) any entity which Executive does not control, directly or indirectly, and which does not compete with Company, or (ii) any publicly held entity, so long as Executive’s aggregate direct and indirect interest does not exceed two percent (2%) of the issued and outstanding securities of any class of securities of such publicly held entity; (b) Executive’s participation in civic and charitable activities, including as a member of a board of a civic or charitable organization, so long as such activities do not interfere with Executive’s performance of Executive’s duties hereunder; and (c) Executive’s performance of consulting services for the entities listed on Exhibit A hereto, provided that such services are limited to 2 hours per month for each listed entity via phone or email (i.e., not in person), and are performed outside of business hours and otherwise in a manner that does not interfere with Executive’s performance of Executive’s duties hereunder.

2. Term; Termination.

(a) Term. Subject to the terms hereof and contingent on the successful consummation of the Arsanis Merger, Executive’s employment hereunder shall become effective on March 13, 2019 (the “Commencement Date”) and shall continue until terminated hereunder by either party (such term of employment shall be referred to herein as the “Term”).

(b) Termination by Company. Notwithstanding anything else contained in this Agreement, Company may terminate Executive’s employment hereunder as follows:

(i) For Cause. Company may terminate Executive’s employment for Cause (as defined below) by written notice by Company to Executive that Executive’s employment is being terminated for Cause, which termination shall be effective on the date of such notice or such later date as specified in writing by Company, provided that if Executive has cured the circumstances giving rise to Cause (as such cure right may be applicable pursuant to the terms and conditions set forth below) then such termination shall not be effective.

(ii) Without Cause. Company may terminate Executive’s employment without Cause, by written notice by Company to Executive that Executive’s employment is being terminated without Cause, which termination shall be effective ninety (90) days after the date of such notice or such later date as specified in writing by Company.

For the purposes of this Agreement, “Cause” shall mean: (A) fraud, embezzlement, or illegal misconduct in connection with Executive’s duties under this Agreement; (B) conviction of a felony involving fraud, dishonesty or breach of trust; (C) willful misconduct or gross negligence in the performance of the duties delegated to Executive; (D) material breach of this Agreement; or (E) material breach of any non-competition, non-solicitation, non-disclosure, and intellectual property assignment agreement between Executive and Company; provided that “Cause” shall not be deemed to have occurred pursuant to subsections (C) or (D) hereof unless Executive has first received written notice specifying in reasonable detail the particulars of such ground and that Company intends to terminate Executive’s employment hereunder for such ground, and if such ground is curable, Executive has failed to cure such ground within a period of thirty (30) days from the date of his receipt of such notice.

(c) Termination by Executive. Notwithstanding anything else contained in this Agreement, Executive may terminate Executive’s employment hereunder as follows:

(i) For Good Reason. Executive may terminate Executive’s employment for Good Reason (as defined below) by written notice by Executive to Company that Executive is terminating Executive’s employment for Good Reason, which termination shall be effective thirty (30) days after the date of such notice; provided that if Company has cured the circumstances giving rise to Good Reason then such termination shall not be effective; or

(ii) Without Good Reason. Executive may terminate Executive’s employment without Good Reason by written notice by Executive to Company that Executive is terminating Executive’s employment, which termination shall be effective ninety (90) days after the date of such notice.

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For the purposes of this Agreement, “Good Reason” shall mean: (A) a material reduction in Executive’s then-current Base Salary; (B) a material diminution in Executive’s authority, duties, or responsibilities; (C) a material change in the geographic location at which the Executive provides services to the Company outside of a fifty (50) mile radius from the then-current location; or (D) any action or inaction by Company that constitutes a material breach of this Agreement; provided that “Good Reason” shall not be deemed to have occurred unless: (1) Executive provides Company with written notice that Executive intends to terminate Executive’s employment hereunder for one of the grounds set forth above within thirty (30) days of such ground first occurring, (2) if such ground is capable of being cured, Company has failed to cure such ground within a period of thirty (30) days from the date of such written notice, and (3) Executive terminates Executive’s employment within seventy five (75) days from the date that Good Reason first occurs. For purposes of clarification, the above-listed conditions shall apply separately to each occurrence of Good Reason and failure to adhere to such conditions in the event of Good Reason shall not disqualify Executive from asserting Good Reason for any subsequent occurrence of Good Reason.

(d) Termination Due to Disability. Notwithstanding anything else contained in this Agreement, Company may terminate Executive’s employment due to Executive’s Disability (as defined below) by written notice to Executive that Executive’s employment is being terminated as a result of Executive’s Disability, which termination shall be effective on the date of such notice or such later date as specified in writing by Company. For the purposes of this Agreement, “Disability” shall mean Executive’s incapacity or inability to perform Executive’s duties and responsibilities as contemplated herein for one hundred twenty (120) days or more within any one (1) year period (cumulative or consecutive), because Executive’s physical or mental health has become so impaired as to make it impossible or impractical for Executive to perform the duties and responsibilities contemplated hereunder. Determination of Executive’s physical or mental health shall be determined by the Board after consultation with a medical expert appointed by mutual agreement between Company and Executive who has examined Executive. Executive hereby consents to such examination and consultation regarding Executive’s health and ability to perform as aforesaid.

3. Compensation.

(a) Base Salary. While Executive is employed hereunder, Executive shall earn a base salary at the annual rate approved by the Board or an appropriate committee thereof (as may be changed from time-to-time, the “Base Salary”). The Base Salary shall be payable in substantially equal periodic installments, at least on a monthly basis, in accordance with Company’s payroll practices as in effect from time to time. Company shall deduct from each such installment all amounts required to be deducted or withheld under applicable law or under any employee benefit plan in which Executive participates.

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(b) Annual Bonus. Executive shall be eligible to receive an annual performance bonus (the “Annual Bonus”) for all years in which Executive is employed by Company hereunder. The Annual Bonus potential shall be in an amount approved by the Board or an appropriate committee thereof, but under no circumstances shall the Annual Bonus potential be less than twenty-five percent (25%) of Executive’s then Base Salary (provided that, as stated below, the amount of any Annual Bonus remains in the Board’s discretion). The amount of the Annual Bonus shall be based on factors such as Executive’s work performance, Company’s financial performance, Company’s business forecasts, Company’s determination of Executive’s achievement of milestones for the applicable year, and economic conditions generally. The actual amount of the Annual Bonus shall be determined by the Board in its sole discretion. The Annual Bonus shall be paid to Executive in no event later than March 15th of the calendar year immediately following the calendar year to which it pertains. Executive must be employed by Company at the time that the Annual Bonus is paid in order to be eligible for, and to be deemed as having earned, such Annual Bonus. Company shall deduct from the Annual Bonus all amounts required to be deducted or withheld under applicable law or under any employee benefit plan in which Executive participates.

(c) Fringe Benefits. Executive shall be entitled to participate in all benefit/welfare plans and fringe benefits provided to employees at the same level as Executive. Executive understands that, except when prohibited by applicable law, Company’s benefit plans and fringe benefits may be amended by Company from time to time in its sole discretion.

(d) Vacation. Consistent with Company’s current policy and given Executive’s tenure with Company, Executive shall be eligible to accrue up to fifteen (15) days of vacation per year, to be scheduled to minimize disruption to Company’s operations. Executive’s vacation use, accrual and carryover shall be subject to the terms and conditions of Company’s vacation policy in effect from time to time.

(e) Reimbursement of Expenses. Company shall reimburse Executive for all ordinary and reasonable out-of-pocket business expenses incurred by Executive in furtherance of Company’s business in accordance with Company’s policies with respect thereto as in effect from time to time. Executive must submit any request for reimbursement no later than ninety (90) days following the date that such business expense is incurred. All reimbursements provided under this Agreement shall be made or provided in accordance with the requirements of Section 409A (“Section 409A”) of the Code and the rules and regulations thereunder, including, where applicable, the requirement that (i) any reimbursement is for expenses incurred during Executive’s lifetime (or during a shorter period of time specified in this Agreement); (ii) the amount of expenses eligible for reimbursement during a calendar year may not affect the expenses eligible for reimbursement in any other calendar year; (iii) the reimbursement of an eligible expense shall be made no later than the last day of the calendar year following the year in which the expense is incurred; and (iv) the right to reimbursement or in kind benefits is not subject to liquidation or exchange for another benefit.

(f) Indemnification. Executive shall be eligible for coverage under Company Directors’ and Officers’ (“D&O”) insurance policies to the same extent and in the same manner to which Company’s similarly situated executives are entitled to coverage under Company D&O insurance policies, subject to the terms and conditions of any such Company D&O insurance policies.

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4. Termination Payments; Severance Benefit.

(a) Payment of Accrued Obligations. Regardless of the reason for any employment termination hereunder, Company shall pay to Executive: (i) the portion of Executive’s Base Salary that has accrued prior to any termination of Executive’s employment and has not yet been paid; (ii) the portion of Executive’s vacation days that have accrued prior to any termination of Executive’s employment and has not yet been used; and (iii) the amount of any expenses properly incurred by Executive on behalf of Company prior to any such termination and has not yet been reimbursed (together, the “Accrued Obligations”) promptly following the effective date of termination, and otherwise within any timeframe required by law. Executive’s entitlement to other compensation or benefits under any Company plan or policy shall be governed by and determined in accordance with the terms of such plan or policy, except as otherwise specified in this Agreement. In the event of Company’s termination of Executive’s employment for Cause or Executive’s termination of Executive’s employment without Good Reason, Executive shall be eligible for the Accrued Obligations and shall not be eligible for any severance or severance-type payments, other than as expressly set forth herein.

(b) Severance in the Event of Termination Without Cause or Resignation for Good Reason. Subject to the terms and conditions of Section 4(d), in the event that Executive’s employment hereunder is terminated by Company without Cause or terminated by Executive for Good Reason, then, in addition to the Accrued Obligations:

(i) Company shall pay Executive an amount equal to continuation of Executive’s monthly Base Salary for a six (6) month period, with such payments to be made in accordance with Company’s normal payroll practices and schedules, less all customary and required taxes and employment-related deductions.

(ii) Company shall pay Executive a pro-rata portion of Executive’s at-target Annual Bonus for the calendar year in which the termination occurs based on the period worked by Executive during such calendar year prior to termination, with such payment to be made in on one lump sum in accordance with Company’s normal payroll practices and schedules, less all customary and required taxes and employment-related deductions.

(iii) In the event that Executive is eligible for coverage under a Company health insurance plan and Executive has elected to have coverage thereunder and was covered thereunder prior to termination, and in the event that Executive chooses to exercise Executive’s right under the Consolidated Omnibus Budget Reconciliation Act of 1985 (“COBRA”) to continue Executive’s participation in such plan, Company shall pay its normal share of the costs for such coverage for a period of up to six (6) months from termination, to the same extent that such insurance is provided to persons then currently employed by Company. Company shall deduct from each of the installments due under Section 4(b)(i) the portion of the monthly premium due from Executive in accordance with the terms of such coverage. Notwithstanding any other provision of this Agreement, this obligation shall cease on the date Executive becomes eligible to receive health insurance benefits through any other employer, and Executive agrees to provide Company with written notice immediately upon becoming eligible for such benefits. Executive’s acceptance of any payment on Executive’s behalf or coverage provided hereunder shall be an express representation to Company that Executive has no such eligibility.

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(iv) Executive shall become vested in the additional number of outstanding time-based equity awards granted to Executive by Company that would have otherwise vested had Executive remained in employment for an additional six (6) months after the termination date.

Subsections (i), (ii), (iii) and (iv) are referred to as the Severance Benefit. The Severance Benefit is expressly subject to the conditions described above and in Section 4(d) below. Any payment or benefit made as part of such Severance Benefit shall be paid less all customary and required taxes and employment-related deductions.

(c) Accelerated Vesting in Event of Termination without Cause or Resignation for Good Reason Following Change of Control. Subject to the terms and conditions of Section 4(d), in the event that a Change of Control (as defined below) occurs and within a period of one (1) year following the Change of Control the Company terminates Executive’s employment without Cause or Executive resigns for Good Reason, then Executive automatically shall become vested in one hundred percent (100%) of outstanding time-based equity awards granted to Executive by Company. The above-described vesting is expressly subject to the conditions described in Section 4(d), and shall be provided less all customary and required taxes and employment-related deductions. For purposes of this section, a “Change of Control” shall mean the occurrence of any of the following events: (i) Ownership. Any “Person” (as such term is used in Sections 13(d) and 14(d) of the Securities Exchange Act of 1934, as amended) becomes the “Beneficial Owner” (as defined in Rule 13d-3 under said Act), directly or indirectly, of securities of Company representing fifty percent (50%) or more of the total voting power represented by Company’s then outstanding voting securities (excluding for this purpose any such voting securities held by Company, or any affiliate, parent or subsidiary of Company, or by any employee benefit plan of Company) pursuant to a transaction or a series of related transactions which the Board does not approve; or (ii) Merger/Sale of Assets. (A) A merger or consolidation of Company whether or not approved by the Board, other than a merger or consolidation which would result in the voting securities of Company outstanding immediately prior thereto continuing to represent (either by remaining outstanding or by being converted into voting securities of the surviving entity or the parent of such corporation) at least fifty percent (50%) of the total voting power represented by the voting securities of Company or such surviving entity or parent of such corporation, as the case may be, outstanding immediately after such merger or consolidation; or (B) the sale or disposition by Company of all or substantially all of Company’s assets.

(d) Conditions. Company shall not be obligated to provide Executive any payment, benefit and/or vesting described in Section 4(b) or Section 4(c) unless and until Executive has executed without revocation a separation agreement in a form acceptable to Company, which must be signed by Executive, returned to Company and be enforceable and irrevocable no later than sixty (60) days following Executive’s separation from service (the “Review Period”), and which shall include, at a minimum, the provision of separation pay and benefits due from Company to Executive as applicable, a complete general release of claims against Company and its affiliated entities and each of their officers, directors and employees, and terms relating to non-disparagement, non-competition, confidentiality, cooperation and the like similar in scope, duration and substance to those terms set forth in the agreement described in Section 5 below. If

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Executive executes and does not revoke such agreement within the Review Period, then provision of payments, benefits and/or vesting shall commence on the first (1st) day following the Review Period, provided that if the last day of the Review Period occurs in the calendar year following the year of termination, then the payment shall not commence until January 2 of such subsequent calendar year, and further provided that, as applied to Section 4(b)(i), (ii) and (iii) as applicable, the first payments/benefits shall include in a lump sum all amounts that were otherwise payable to Executive from the date of Executive’s separation from service occurred through such first payment.

(e) COBRA. If the payment of any COBRA or health insurance premiums by Company on behalf of Executive as described herein would otherwise violate any applicable nondiscrimination rules or cause the reimbursement of claims to be taxable under the Patient Protection and Affordable Care Act of 2010, together with the Health Care and Education Reconciliation Act of 2010 (collectively, the “Act”) or Section 105(h) of the Code, the COBRA premiums paid by Company shall be treated as taxable payments (subject to customary and required taxes and employment-related deductions) and be subject to imputed income tax treatment to the extent necessary to eliminate any discriminatory treatment or taxation under the Act or Section 105(h) of the Code. If Company determines in its sole discretion that it cannot provide the COBRA benefits described herein under Company’s health insurance plan without potentially violating applicable law (including, without limitation, Section 2716 of the Public Health Service Act), Company shall in lieu thereof provide to Executive a taxable lump-sum payment in an amount equal to the sum of the monthly (or then remaining) COBRA premiums that Executive would be required to pay to maintain Executive’s group health insurance coverage in effect on the separation date for the remaining portion of the period for which Executive shall receive the payments described in Sections 4(b) or 4(c) above.

(f) No Other Payments or Benefits Owing. The payments and benefits set forth in this Section 4 shall be the sole amounts owing to Executive upon termination of Executive’s employment for the reasons set forth above and Executive shall not be eligible for any other payments or other forms of compensation or benefits. The payments and benefits set forth in this Section shall be the sole remedy, if any, available to Executive in the event that Executive brings any claim against Company relating to the termination of Executive’s employment under this Agreement.

(g) No Mitigation of Damages Offset. Except as otherwise may be expressly provided herein, Executive shall not be required to mitigate any amounts due or provided him under this Agreement by seeking other employment or otherwise. Any payments made by Company to Executive after the termination of employment shall not be reduced by any compensation Executive receives from any subsequent employment or source.

5. Non-Competition, Non-Solicitation, Non-Disclosure Agreement. Executive has signed and agrees to continue to abide by Company’s Non-Competition, Non-Solicitation, Non-Disclosure, and Intellectual Property Agreement.

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6. Code Sections 409A and 280G.

(a) In the event that the payments or benefits set forth in Section 4 constitute “non-qualified deferred compensation” subject to Section 409A, then the following conditions apply to such payments or benefits:

(i) Any termination of Executive’s employment triggering payment of benefits under Section 4 must constitute a “separation from service” under Section 409A(a)(2)(A)(i) of the Code and Treas. Reg. §1.409A-1(h) before distribution of such benefits can commence. To the extent that the termination of Executive’s employment does not constitute a separation of service under Section 409A(a)(2)(A)(i) of the Code and Treas. Reg. §1.409A-1(h) (as the result of further services that are reasonably anticipated to be provided by Executive to Company at the time Executive’s employment terminates), any such payments under Section 4 that constitute deferred compensation under Section 409A shall be delayed until after the date of a subsequent event constituting a separation of service under Section 409A(a)(2)(A)(i) of the Code and Treas. Reg. §1.409A-1(h). For purposes of clarification, this Section 6(a) shall not cause any forfeiture of benefits on Executive’s part, but shall only act as a delay until such time as a “separation from service” occurs.

(ii) Notwithstanding any other provision with respect to the timing of payments under Section 4 if, at the time of Executive’s termination, Executive is deemed to be a “specified employee” of Company (within the meaning of Section 409A(a)(2)(B)(i) of the Code), then limited only to the extent necessary to comply with the requirements of Section 409A, any payments to which Executive may become entitled under Section 4 which are subject to Section 409A (and not otherwise exempt from its application) shall be withheld until the first (1st) business day of the seventh (7th) month following the termination of Executive’s employment, at which time Executive shall be paid an aggregate amount equal to the accumulated, but unpaid, payments otherwise due to Executive under the terms of Section 4.

(b) It is intended that each installment of the payments and benefits provided under Section 4 shall be treated as a separate “payment” for purposes of Section 409A. Neither Company nor Executive shall have the right to accelerate or defer the delivery of any such payments or benefits except to the extent specifically permitted or required by Section 409A.

(c) Notwithstanding any other provision of this Agreement to the contrary, this Agreement shall be interpreted and at all times administered in a manner that avoids the inclusion of compensation in income under Section 409A, or the payment of increased taxes, excise taxes or other penalties under Section 409A. The parties intend this Agreement to be in compliance with Section 409A. Executive acknowledges and agrees that Company does not guarantee the tax treatment or tax consequences associated with any payment or benefit arising under this Agreement, including but not limited to consequences related to Section 409A.

(d) If any payment or benefit Executive would receive under this Agreement, when combined with any other payment or benefit Executive receives pursuant to a Change of Control (for purposes of this section, a “Payment”) would: (i) constitute a “parachute payment” within the meaning of Section 280G the Code; and (ii) but for this sentence, be subject to the excise tax imposed by Section 4999 of the Code (the “Excise Tax”), then such Payment shall be either: (A) the full amount of such Payment; or (B) such lesser amount (with cash payments being reduced before stock option compensation) as would result in no portion of the Payment being subject to the Excise Tax, whichever of the foregoing amounts, taking into account the applicable federal, state and local employments taxes, income taxes, and the Excise Tax, results in Executive’s receipt, on an after-tax basis, of the greater amount of the Payment notwithstanding that all or some portion of the Payment may be subject to the Excise Tax.

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7. General.

(a) Notices. Except as otherwise specifically provided herein, any notice required or permitted by this Agreement shall be in writing and shall be delivered as follows with notice deemed given as indicated: (i) by personal delivery when delivered personally; (ii) by overnight courier upon written verification of receipt; (iii) by facsimile transmission upon acknowledgment of receipt of electronic transmission; or (iv) by certified or registered mail, return receipt requested, upon verification of receipt.

Notices to Executive shall be sent to the last known address in Company’s records or such other address as Executive may specify in writing.

Notices to Company shall be sent to:

X4 Pharmaceuticals, Inc.

955 Massachusetts Ave., 4th Floor

Cambridge, MA 02139

Attention: Chair, Board of Directors

with a copy to:

Mintz, Levin, Cohn, Ferris, Glovsky & Popeo, P.C.

One Financial Center

Boston, MA, 02111

Attn: John J. Cheney, Esq.

(b) Modifications and Amendments. The terms and provisions of this Agreement may be modified or amended only by written agreement executed by the parties hereto.

(c) Waivers and Consents. The terms and provisions of this Agreement may be waived, or consent for the departure therefrom granted, only by written document executed by the party entitled to the benefits of such terms or provisions. No such waiver or consent shall be deemed to be or shall constitute a waiver or consent with respect to any other terms or provisions of this Agreement, whether or not similar. Each such waiver or consent shall be effective only in the specific instance and for the purpose for which it was given, and shall not constitute a continuing waiver or consent.

(d) Assignment. Company may assign its rights and obligations hereunder to any person or entity that succeeds to all or substantially all of Company’s business or that aspect of Company’s business in which Executive is principally involved. Executive may not assign Executive’s rights and obligations under this Agreement without the prior written consent of Company.

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(e) Governing Law; Jury Waiver. This Agreement and the rights and obligations of the parties hereunder shall be construed in accordance with and governed by the law of Massachusetts without giving effect to the conflict of law principles thereof. Any legal action or proceeding with respect to this Agreement shall be brought in the courts of the Commonwealth of Massachusetts or the United States of America for the District of Massachusetts. By execution and delivery of this Agreement, each of the parties hereto accepts for itself and in respect of its property, generally and unconditionally, the exclusive jurisdiction of the aforesaid courts. ANY ACTION, DEMAND, CLAIM OR COUNTERCLAIM ARISING UNDER OR RELATING TO THIS AGREEMENT SHALL BE RESOLVED BY A JUDGE ALONE AND EACH OF COMPANY AND EXECUTIVE WAIVES ANY RIGHT TO A JURY TRIAL THEREOF.

(f) Headings and Captions. The headings and captions of the various subdivisions of this Agreement are for convenience of reference only and shall in no way modify or affect the meaning or construction of any of the terms or provisions hereof.

(g) Entire Agreement. This Agreement, together with the other agreements specifically referenced herein, embodies the entire agreement and understanding between the parties hereto with respect to the subject matter hereof and supersedes all prior oral or written agreements and understandings relating to the subject matter hereof. No statement, representation, warranty, covenant or agreement of any kind not expressly set forth in this Agreement shall affect, or be used to interpret, change or restrict, the express terms and provisions of this Agreement.

(h) Counterparts. This Agreement may be executed in two or more counterparts, and by different parties hereto on separate counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument. For all purposes a signature by fax shall be treated as an original.

[Signature Page to Follow]

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IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of the date first written above.

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EXHIBIT A

PERMITTED CONSULTING ENGAGEMENTS

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Exhibit 10.5

LICENSE AGREEMENT

This License Agreement (this “Agreement”) is executed as of July 10, 2014 (the “Effective Date”) by and between Genzyme Corp., a corporation having an address at 500 Kendall Street, Cambridge, MA 02142 (“Genzyme” or “Licensor”) and X4 Pharmaceuticals, LLC, a Massachusetts limited liability company having an address at 281 School Street, Belmont, MA 02478, United States (“X4”). Genzyme and X4 are sometimes referred to herein individually as a “Party” and collectively as the “Parties.”

RECITALS

WHEREAS, Genzyme controls certain intellectual property rights in the Territory (as defined herein) with respect to the Licensed Compounds (as defined herein) and Licensed Products (as defined herein); and

WHEREAS, Genzyme wishes to grant to X4, and X4 wishes to receive, an exclusive license under such intellectual property rights to Develop (as defined herein) and Commercialize (as defined herein) Licensed Products in the Territory, in each case in accordance with the terms and conditions set forth below.

NOW, THEREFORE, in consideration of the premises and the mutual promises and conditions hereinafter set forth, and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the Parties, intending to be legally bound, do hereby agree as follows:

ARTICLE 1

DEFINITIONS

Unless otherwise specifically provided herein, the following terms shall have the following meanings:

1.1    “Acceptance” shall mean [***].

1.2    “Accountant” has the meaning set forth in Section 6.12.

1.3    “Adverse Event” means (a) the development of an undesirable medical condition or the deterioration of a pre-existing medical condition in a patient or clinical investigation subject during or following exposure to or use of a Licensed Product, whether or not considered causally related to such Licensed Product, (b) the exacerbation in a patient or clinical investigation subject of any pre-existing condition occurring during or following exposure to or use of a Licensed Product, or (c) any other adverse experience or adverse drug experience (as described in the FDA’s Investigational New Drug safety reporting and NDA post-marketing reporting regulations, 21 C.F.R. §§312.32 and 314.80, respectively, and any applicable corresponding regulations outside the United States, in each case as may be amended from time to time), of a patient or clinical investigation subject occurring during or following exposure to or

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

use of a Licensed Product. For purposes of this Agreement, “undesirable medical condition” includes symptoms (e.g., nausea, chest pain), signs (e.g., tachycardia, enlarged liver) or the abnormal results of an investigation (e.g., laboratory findings, electrocardiogram), including unfavorable side effects, toxicity, injury, overdose or sensitivity reactions.

1.4    “Agreement” has the meaning set forth in the preamble hereto.

1.5    “Affiliate” means, with respect to a Party, any Person that, directly or indirectly, through one or more intermediaries, controls, is controlled by or is under common control with such Party. For purposes of this definition, “control” and, with correlative meanings, the terms “controlled by” and “under common control with” means (a) the possession, directly or indirectly, of the power to direct the management or policies of a business entity, whether through the ownership of voting securities, by contract relating to voting rights or corporate governance, or otherwise, or (b) the ownership, directly or indirectly, of more than 50% of the voting securities or other ownership interest of a business entity (or, with respect to a limited partnership or other similar entity, status as a general partner).

1.6    “Allo-HSCT Treatment” means allogeneic hematopoietic stem cell transplantation (i.e. where the donor is a different person than the recipient).

1.7    “Annual Net Sales” means Net Sales of all Licensed Products in the Territory (excluding Net Sales of each Licensed Product in any country in the Territory for which the Royalty Term for such Licensed Product and country has expired) in a particular Calendar Year.

1.8    “Applicable Law” means applicable laws, rules and regulations, including any rules, regulations, guidelines or other requirements of the Regulatory Authorities that may be in effect from time to time and applicable to a particular activity hereunder in the Territory.

1.9    “Auto-HSCT Treatments” means autologous hematopoietic stem cell transplantation, (i.e. where the donor and the recipient are one and a same person).

1.10    “Breaching Party” has the meaning set forth in Section 12.3.

1.11    “Business Day” means a day other than a Saturday or Sunday and any other day on which banking institutions in New York, New York, United States are not closed.

1.12    “Calendar Quarter” means, with respect to the first such Calendar Quarter, the period beginning on the Execution Date and ending on the last day of the calendar quarter within which the Execution Date falls and thereafter each successive period of three calendar months commencing on January 1, April 1, July 1 and October 1.

1.13    “Calendar Year” means, with respect to the first such Calendar Year, the period beginning on the Execution Date and ending on December 31 of the calendar year within which the Execution Date falls and thereafter each successive period of twelve (12) calendar months commencing on January 1 and ending on December 31.

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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1.14    “Change of Control” means the purchase (direct or indirect, either through merger or otherwise) by a Third Party of (i) fifty per cent (50%) or more of the existing Units in X4 or (ii) the whole or a substantial part of the business of X4 to which this Agreement relates. For clarity, the Parties agree that (a) any Licensed Product shall constitute a substantial part of the business of X4 for purposes of this definition and (b) an investment transaction by venture capital or other financial investors not engaged in the pharmaceutical or biotechnology business and not otherwise affiliated with a pharmaceutical or biotechnology company, the sole purpose of which is to raise capital for X4 shall not be deemed to be a Change of Control for purposes of this Agreement.

1.15    “Clinical Data” means all data, reports and results with respect to the Licensed Compound and the Licensed Products made, collected or otherwise generated under or in connection with the conduct of Clinical Studies.

1.16    “Clinical Studies” means human clinical trials for a Licensed Product and any other tests and studies for a Licensed Product in human subjects, in any case, conducted by or on behalf of X4 pursuant to this Agreement.

1.17    “Combination Product” means a single product that consists of or contains a Licensed Compound as an active ingredient together with one or more other therapeutically active ingredients and is sold either as a fixed dose or as separate doses in a single package.

1.18    “Commercialization” means, with respect to a Licensed Product, any and all activities (whether before or after Regulatory Approval) directed to the marketing, promotion and sale of such Licensed Product in the Field in the Territory, including pre-launch and post-launch marketing, promoting, marketing research, distributing, offering to commercially sell and commercially selling such Licensed Product, importing, exporting or transporting such Licensed Product for commercial sale, medical education activities with respect to such Licensed Product, conducting Clinical Studies that are not required to obtain or maintain Regulatory Approval for such Licensed Product for an indication, which may include epidemiological studies, modeling and pharmacoeconomic studies, post-marketing surveillance studies, investigator sponsored studies and health economics studies and regulatory affairs (including interacting with Regulatory Authorities) with respect to the foregoing. When used as a verb, “Commercializing” means to engage in Commercialization and “Commercialize” and “Commercialized” shall have corresponding meanings.

1.19    “Commercially Reasonable Efforts” means [***].

1.20    “Complaining Party” has the meaning set forth in Section 12.3.

1.21    “Confidential Information” has the meaning set forth in Section 9.1.

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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1.22    “Control” means, with respect to any Information, Regulatory Documentation, Patent, or other intellectual property right, possession of the right, whether directly or indirectly, and whether by ownership, license or otherwise (other than by operation of the license and other grants in Section 2.1), to assign or grant a license, sublicense or other right to or under such Information, Regulatory Documentation, Patent, or other intellectual property right as provided for herein without violating the terms of any agreement or other arrangement with any Third Party. “Controlled” has a corresponding meaning.

1.23    “Controlling Party” has the meaning set forth in Section 7.4.1.

1.24    “CREATE Act” has the meaning set forth in Section 7.2.4.

1.25    “Cumulative Net Sales” means total Net Sales of a Licensed Product in the Territory since the First Commercial Sale of such Licensed Product in the Territory (excluding Net Sales of each Licensed Product in any country in the Territory for which the Royalty Term for any Licensed Product and country has expired). For purposes of clarity, Net Sales of any Sublicensee of X4 shall be included as part of Net Sales solely for purposes of determining Cumulative Net Sales.

1.26    “Current Good Manufacturing Practices” or “cGMP” means current good manufacturing practices and standards, as provided for (and as amended from time to time) in the Current Good Manufacturing Practice regulations promulgated by the FDA under the United States Food, Drug and Cosmetic Act (21 C.F.R. Part 210 et seq.) and in the European Community Directive 2003/94/EC (Principles and guidelines of good manufacturing practice for medicinal products), as well as applicable documents developed by the International Conference on Harmonization (ICH) harmonized Tripartite Guideline, Good Manufacturing Practice Guide for Active Pharmaceutical Ingredients, Q7a.

1.27    “Development” means, with respect to a Licensed Product, all activities related to research, preclinical and other non-clinical testing, test method development and stability testing, toxicology, formulation, the conduct of Manufacture Process Development, the conduct of Clinical Studies, including Manufacturing in support thereof (but excluding any commercial Manufacturing), the conduct of statistical analysis and report writing, the preparation and submission of Drug Approval Applications for such Licensed Product, regulatory affairs with respect to the foregoing and all other activities necessary or reasonably useful or otherwise requested or required by a Regulatory Authority as a condition or in support of obtaining or maintaining a Regulatory Approval for such Licensed Product. When used as a verb, “Develop” means to engage in Development.

1.28    “Development Plan” means the plan for the Development of the Licensed Products as described in Section 3.1.1, as updated from time to time pursuant to Section 3.1.1.

1.29    “Disclosing Party” has the meaning set forth in Section 9.1.

1.30    “Dollars” or “$” means United States Dollars.

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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1.31    “Drug Approval Application” means a New Drug Application (an “NDA”) as defined in the FFDCA and the regulations promulgated thereunder (including all additions, supplements, extensions and modifications thereto), or any corresponding foreign application in the Territory, including, with respect to the European Union, a Marketing Authorization Application (an “MAA”) filed with the EMA pursuant to the centralized approval procedure or with the applicable Regulatory Authority of a country in Europe with respect to the mutual recognition or any other national approval procedure (including all additions, supplements, extensions and modifications thereto).

1.32    “Effective Date” has the meaning set forth in the preamble hereto.

1.33    “EMA” means the European Medicines Agency and any successor agency thereto.

1.34    “European Union” means the economic, scientific and political organization of member states as it may be constituted from time to time, which as of the Effective Date consists of Austria, Belgium, Bulgaria, Czech Republic, Croatia, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, The Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden and the United Kingdom of Great Britain and Northern Ireland and that certain portion of Cyprus included in such organization.

1.35    “Executive Officers” means the Chief Executive Officer of X4 and the Head of Strategy & Business Development of Genzyme (or his/her designee).

1.36    “Exploit” means, with respect to a Licensed Product, to make, have made, import, have imported, use, sell or offer for sale, research, Develop, Commercialize, register, Manufacture, have Manufactured, hold or keep (whether for disposal or otherwise), have used, export, have exported, transport, distribute, have distributed, promote, have promoted, market or have sold or otherwise dispose of such Licensed Product and “Exploitation” means the act of Exploiting a Licensed Product.

1.37    “FDA” means the United States Food and Drug Administration and any successor agency thereto.

1.38    “FFDCA” means the United States Food, Drug, and Cosmetic Act, as amended from time to time.

1.39    “Field” means all therapeutic, prophylactic and diagnostic uses in humans for all indications, excluding (a) the Mozobil Indications, and (b) any use for Auto-HSCT Treatments and Allo-HSCT Treatments.

1.40    “Financial Commitment” means a private placement of capital or debt ownership interests or securities of X4 (including rights or options to acquire ownership interests) which results in aggregate proceeds to X4 of at least [***].

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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1.41    “First Commercial Sale” means, with respect to a Licensed Product in a country in the Territory, the first sale to a Third Party for monetary value for use or consumption by the general public of such Licensed Product in such country after the applicable Regulatory Authority has approved the Drug Approval Application for such Licensed Product in such country. Sales prior to the approval of the applicable Drug Approval Application, such as so-called “treatment IND sales”, “named patient sales” and “compassionate use sales”, shall not constitute a First Commercial Sale.

1.42    “Force Majeure Event” has the meaning set forth in Section 13.1.

1.43    “Genzyme” has the meaning set forth in the preamble hereto.

1.44    “Genzyme Indemnitees” has the meaning set forth in Section 11.1.

1.45    “Genzyme Knowledge” has the meaning set forth in Section 10.3.

1.46    “IFRS” means International Financial Reporting Standards adopted by the International Accounting Standards Board or applicable generally accepted accounting principles, in each case consistently applied.

1.47    “IND” means an investigational new drug application filed with the FDA for authorization to commence Clinical Studies in the United States (including all additions, supplements, extensions and modifications thereto), or any corresponding foreign application in any country or region in the Territory (including all additions, supplements, extensions and modifications thereto).

1.48    “Indemnification Claim Notice” has the meaning set forth in Section 11.3.

1.49    “Indemnified Party” has the meaning set forth in Section 11.3.

1.50    “Indemnifying Party” means the Party from whom indemnification is sought pursuant to Section 11.1 or Section 11.2.

1.51    “Information” means all technical, scientific and other know-how and information, trade secrets, knowledge, technology, means, methods, processes, practices, formulas, instructions, skills, techniques, procedures, experiences, technical assistance, designs, drawings, assembly procedures, computer programs, specifications, data, results and other material, including Regulatory Documentation, pre-clinical trial results and Clinical Study results, Manufacturing procedures, test procedures, and purification and isolation techniques (whether or not confidential, proprietary, patented or patentable) in written, electronic or any other form now known or hereafter developed, and all other discoveries, developments, inventions (whether or not confidential, proprietary, patented or patentable), and tangible embodiments of any of the foregoing.

1.52    “Infringement” has the meaning set forth in Section 7.3.1.

1.53    “Infringement Notice” has the meaning set forth in Section 7.3.1.

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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1.54    “Invoiced Sales” has the meaning set forth in the definition of “Net Sales”.

1.55    “LIBOR” means the London Interbank Offered Rate for deposits in Euros having a maturity of one month published by the British Bankers’ Association, as adjusted from time to time on the first London business day of each month.

1.56    “Licensed Compound” means (a) any of the compounds listed on Schedule 1.56 and (b) any other compound that is otherwise covered by a Valid Claim of a Licensed Patent. Notwithstanding the foregoing, for the avoidance of doubt, plerixafor (also known as AMD3100 and 1,1’-[1,4-phenylene-bis(methylene)]-bis-1,4,8,11- tetraazacyclotetradecane, and by the trade name Mozobil^®) is not a Licensed Compound.

1.57    “Licensed Know-How” means the Information Controlled by Genzyme or its Affiliates during the Term that is related to, and necessary or useful for the Development and/or Commercialization of, the Licensed Compounds and/or Licensed Products but excluding any Information to the extent claimed or covered by published Licensed Patents. For purposes of clarity, Licensed Know-How is listed on Schedule 1.57 attached hereto.

1.58    “Licensed Patents” means (a) the national, regional and international patents and patent applications, including provisional patent applications set forth on Schedule 1.58, (b) all patent applications Controlled by Genzyme or its Affiliates during the Term that claim priority to any patents or patent applications in clause (a), including divisionals, continuations, continuations-in-part, converted provisionals, and continued prosecution applications, as well as any substitute applications with respect to any patent applications in clause (a), (c) any and all patents that have issued or in the future may issue from any of foregoing patent applications in clause (a) or clause (b), to the extent Controlled by Genzyme or its Affiliates during the Term, including utility patents, utility models, petty patents and design patents and certificates of invention, and (d) any and all re-issues re-examinations renewals, revalidations, restorations or extensions (including any supplementary protection certificates and the like) of any of the foregoing patents or patent applications in clause (a), clause (b), or clause (c) to the extent Controlled by Genzyme or its Affiliates during the Term.

1.59    “Licensed Product” means any pharmaceutical product containing a Licensed Compound, alone or in combination with one or more other active ingredients.

1.60    “Licensed Product Agreement” means, with respect to a Licensed Product, any agreement entered into by and between X4 or any of its Sublicensees or its or their respective Affiliates, on the one hand, and one or more Third Parties, on the other hand, that relates to the Exploitation of such Licensed Product in the Field in the Territory, including (a) any agreement pursuant to which X4, its Sublicensees or its or their respective Affiliates receives any license or other rights to Exploit such Licensed Product, (b) supply agreements pursuant to which X4, its Sublicensees or its or their respective Affiliates obtain or will obtain quantities of such Licensed Product, (c) clinical trial agreements with respect to the conduct of clinical trials for such Licensed Product, (d) contract research organization agreements with respect to the conduct of services for such Licensed Product and (e) service agreements with respect to the conduct of services for such Licensed Product.

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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1.61    “Losses” has the meaning set forth in Section 11.1.

1.62    “MAA” has the meaning set forth in the definition of “Drug Approval Application.”

1.63    “Major Markets” means each of the United States, the United Kingdom, Spain, Italy, France, Germany, Japan, Brazil, Russia, India and China.

1.64    “Manufacture” and “Manufacturing” means, with respect to a Licensed Product, all activities related to the production, manufacture, processing, filling, finishing, packaging, labeling, release, shipping, holding, conduct of Manufacture Process Development, stability testing, quality assurance or quality control of such Licensed Product or any intermediate thereof.

1.65    “Manufacture Process Development” means the process development, process qualification and validation and scale-up of the process to manufacture a Licensed Product and analytic development and product characterization with respect thereto.

1.66    “Markings” has the meaning set forth in Section 4.6.

1.67    “Material Safety Issue” has the meaning set forth in Section 12.4.2.

1.68    “Milestone Event” means each of the events identified as a milestone event in Section 6.4.1.

1.69    “Monetization” means the monetization of all or a portion of Genzyme’s rights to receive payments under this Agreement, including by means of a direct sale (through an auction process or otherwise) or a financing (through a borrowing of loans, an offering of securities or otherwise).

1.70    “Mozobil Indications” means mobilization of hematopoietic stem cells to the peripheral blood for collection with or without use of G-CSF and subsequent autologous transplantation in human patients with a) lymphoma or b) multiple myeloma.

1.71    “NDA” has the meaning set forth in the definition of “Drug Approval Application.”

1.72    “Net Sales” means, for any period, the gross amount invoiced by X4 or any of its Affiliates (or, for the sole purpose of calculating Cumulative Net Sales hereunder, by X4’s Sublicensees and their Affiliates) for the sale of a Licensed Product, as applicable (the “Invoiced Sales”), less deductions for: [***]. Any of the deductions listed above that involves a payment by X4 or any of its Affiliates (or, for the sole purpose of calculating

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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Cumulative Net Sales hereunder, by X4’s Sublicensees and their Affiliates) shall be taken as a deduction in the Calendar Quarter in which the payment is accrued by such entity. For purposes of determining Net Sales, a Licensed Product shall be deemed to be sold when invoiced and a “sale” shall not include transfers or dispositions of such Licensed Product for pre-clinical or clinical purposes or as samples, in each case, without charge. In the case of pharmacy incentive programs, hospital performance incentive programs, chargebacks, disease management programs, similar programs or discounts on portfolio product offerings, all rebates, discounts and other forms of reimbursements shall be allocated among products on the basis on which such rebates, discounts and other forms of reimbursements were actually granted or, if such basis cannot be determined, in accordance with X4’s or its Affiliates’ (or, for the sole purpose of calculating Cumulative Net Sales hereunder, with X4’s Sublicensees’ and their Affiliates’) existing allocation method; provided, that, any such allocation shall be done in accordance with Applicable Law, including any price reporting laws, rules and regulations. X4’s or any of its Affiliates’ transfer of any Licensed Product to an Affiliate or Sublicensee shall not result in any Net Sales. In the event a Licensed Product is sold which is or comprises a Combination Product, then Net Sales with respect to such Combination Product shall be calculated by multiplying the Net Sales (as described above) of the applicable Combination Product by the fraction A over A+B, in which A is the average sales price in such country in the applicable Calendar Quarter of Licensed Products containing as therapeutically active ingredients only the Licensed Compound (in the same doses and dosage form), and B is the average sales price in such country in the applicable Calendar Quarter of products that do not contain the Licensed Compound and which contain as therapeutically active ingredients all of (and only) the other therapeutically active ingredients that are contained in such Combination Product (in the same doses and dosage form). In the event there are no such separate sales of the Licensed Product used to determine A or the other product used to determine B for a given Combination Product in such country during the applicable Calendar Quarter, Net Sales with respect to such Combination Product shall be determined by the Parties in good faith, based upon commercially reasonable standards and available market information, using values of A and B where A is equal to the relative value, to the end-user, of the Licensed Compound contained in the applicable Combination Product, and B is equal to the relative value, to the end-user, of all the other therapeutically active ingredients included in the applicable Combination Product without the Licensed Compound.

1.73    “Non-Controlling Party” has the meaning set forth in Section 7.4.1.

1.74    “Party” and “Parties” each has the meaning set forth in the preamble hereto.

1.75    “Patents” means (a) all national, regional and international patent applications, including provisional patent applications and PCT applications, continuations, continuations in part, divisionals, and registration confirmations, and (b) all national or regional patents, including utility patents, utility models, petty patents, certificates of invention and design patents including any and all reissues, re-examinations, renewals, revalidations, restorations or extensions (including any supplementary protection certificates and the like).

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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1.76    “Payments” has the meaning set forth in Section 6.8.

1.77    “Person” means an individual, sole proprietorship, partnership, limited partnership, limited liability partnership, corporation, limited liability company, business trust, joint stock company, trust, unincorporated association, joint venture or other similar entity or organization, including a government or political subdivision, department or agency of a government.

1.78    “Phase II Clinical Trial” means a Clinical Study, the principal purpose of which is a determination of safety and efficacy of a Licensed Product in the target patient population or a similar Clinical Study prescribed by the Regulatory Authorities, from time to time, pursuant to Applicable Law or otherwise as more fully defined in 21 C.F.R. §312.21(b), as amended.

1.79    “Phase III Clinical Trial” means a Clinical Study on a sufficient number of subjects that is designed to establish that a Licensed Product is safe and efficacious for its intended use and to determine warnings, precautions and adverse reactions that are associated with such Licensed Product in the dosage range to be prescribed, as more fully defined in 21 C.F.R. §312.21(c), as amended, which Clinical Study is intended to support Regulatory Approval of such Licensed Product, including all tests and studies that are required by the FDA from time to time, pursuant to Applicable Law or otherwise.

1.80    “Product Labeling” means, with respect to a Licensed Product in a country in the Territory, (a) the Regulatory Authority-approved full prescribing information for such Licensed Product for such country, including any required patient information and (b) all labels and other written, printed or graphic matter upon any container, wrapper or any package insert utilized with or for such Licensed Product in such country.

1.81    “Product Trademarks” means the Trademark(s) to be used by X4, or its Affiliates or Sublicensees for the Commercialization of the Licensed Products in the Field in the Territory and any registrations thereof or any pending applications relating thereto in the Territory (excluding, in any event, any Trademarks that include any corporate name or logo of Genzyme or its Affiliates).

1.82    “Prosecution and Maintenance” has the meaning set forth in Section 7.2.1.

1.83    “Receiving Party” has the meaning set forth in Section 9.1.

1.84    “Regulatory Approval” means, with respect to a Licensed Product in a country in the Territory, any and all approvals (including Drug Approval Applications), licenses, registrations or authorizations of any Regulatory Authority necessary to commercially distribute, sell or market such Licensed Product in such country, including, where applicable, (a) pricing or reimbursement approval in such country, (b) pre- and post-approval marketing authorizations (including any prerequisite Manufacturing approval or authorization related thereto) and (c) labeling approval.

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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1.85    “Regulatory Authority” means any applicable supra-national, federal, national, regional, state, provincial or local regulatory agencies, departments, bureaus, commissions, councils or other government entities regulating or otherwise exercising authority with respect to the Exploitation of a Licensed Compound or a Licensed Product in the Territory.

1.86    “Regulatory Documentation” means all (a) applications (including all INDs and Drug Approval Applications), registrations, licenses, authorizations and approvals (including all Regulatory Approvals), (b) correspondence and reports submitted to or received from Regulatory Authorities (including minutes and official contact reports relating to any communications with any Regulatory Authority) and all supporting documents with respect thereto, including all regulatory drug lists, advertising and promotion documents, Adverse Event files and complaint files and (c) Clinical Data and any other data contained in any of the foregoing, in each case ((a), (b) and (c)), relating to the Licensed Product.

1.87    “Regulatory Exclusivity” means the period of data, market or other regulatory exclusivity under the FFDCA, European Parliament and Council Regulations (EC) Nos. 726/2004, 141/2000 and 1901/2006, or national implementations of Article 10 of Directive 2001/83/EC, and all equivalents (including in the United States and the European Union) of any of the foregoing.

1.88    “Royalty Term” means, with respect to each Licensed Product and each country in the Territory, the period beginning on the date of the First Commercial Sale of such Licensed Product in such country, and ending on the latest to occur of (a) the expiration of the last-to-expire Valid Claim within the Licensed Patents in such country that would be infringed by the sale of such Licensed Product in such country; (b) the expiration of Regulatory Exclusivity in such country for such Licensed Product and (c) the tenth (10^th) anniversary of the First Commercial Sale of such Licensed Product in such country.

1.89    “Sublicense” means an exclusive sublicense to Commercialize a Licensed Product granted by X4 pursuant to Section 2.3.2 to a Sublicensee. For clarity, any subcontracting agreement meeting the requirements of Section 3.5 or Section 4.8 pursuant to which X4 subcontracts the exercise of its rights and/or the performance of its obligations under this Agreement shall not constitute a Sublicense.

1.90    “Sublicensee” means a Person, other than an Affiliate, that is granted a Sublicense by X4.

1.91    “Sublicense Percentage” means (a) with respect to a Sublicense granted with respect to a Licensed Product prior to the dosing of the first patient in the first Phase II Clinical Trial conducted for such Licensed Product, [***]; (b) with respect to a Sublicense granted with respect to a Licensed Product on or after the dosing of the first patient in the first Phase II Clinical Trial for such Licensed Product and prior to the dosing of the first patient in the first Phase III Clinical Trial conducted for such Licensed Product, [***]; and (c) with respect to a Sublicense granted with respect to a Licensed Product on or after the dosing of the first patient in the first Phase III Clinical Trial conducted for such Licensed Product, [***].

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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1.92    “Sublicense Revenue” means cash payments received by X4 or its Affiliate from their respective Sublicensees pursuant to a Sublicense in consideration for the grant of a Sublicense, including any upfront payments, license maintenance fees, development or regulatory or sales milestone payments [***]. Notwithstanding the foregoing, Sublicense Revenue will not include [***].

1.93    “Term” has the meaning set forth in Section 12.2.

1.94    “Termination Notice Period” has the meaning set forth in Section 12.3.

1.95    “Territory” means worldwide.

1.96    “Third Party” means any Person other than Genzyme, X4 and their respective Affiliates.

1.97    “Third Party Claims” has the meaning set forth in Section 11.1.

1.98    “Trademark” means any word, name, symbol, color, designation or device or any combination thereof that functions as a source identifier, including any trademark, trade dress, brand mark, service mark, trade name, brand name, logo or business symbol, whether or not registered.

1.99    “Trigger Notice” has the meaning set forth in Section 4.7.

1.100    “United States” means the United States of America, including all possessions and territories thereof.

1.101    “Valid Claim” means a pending or issued claim of a patent or patent application which: (a) has not been held unpatentable, invalid or unenforceable by a court or other government agency of competent jurisdiction in a decision from which no appeal can or has been taken; and (b) which has not been admitted to be invalid or unenforceable through reissue, re-examination, disclaimer or otherwise. Notwithstanding the foregoing, in case of pending patent applications, it is understood and agreed that if the corresponding claim in the patent applications: (i) has been limited or cancelled because of patentability requirements such that the corresponding claim does not cover the applicable Licensed Product; (ii) has lapsed; (iii) has been finally rejected (and the rejection has been affirmed on appeal or the time for appeal or petition has lapsed); (iv) has been finally revoked (and the revocation has been affirmed on appeal or the time for appeal or petition has lapsed); or (v) [***], then such corresponding claim in such corresponding patent application pending in any country will not be deemed to be a Valid Claim.

1.102    “X4” has the meaning set forth in the preamble hereto.

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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1.103    “X4 First Financing” means the closing by X4, in a single transaction or a series of transaction, of a financing round in which X4 receives from one or more Third Parties funding in an aggregate amount of not less than [***] in exchange for debt or equity ownership interests or securities of X4.

1.104    “X4 Indemnitees” has the meaning set forth in Section 11.2.

1.105    “X4 Know-How” means any Information Controlled by X4 or its Affiliates as of the effective date of termination of this Agreement by Genzyme pursuant to Section 12.3 and/or 12.5 that is not generally known and is necessary or useful for the Exploitation of a Licensed Product in the Field in the Territory, but excluding any Information to the extent covered or claimed by published X4 Patents.

1.106    “X4 Patents” means any Patents Controlled by X4 or its Affiliates as of the effective date of termination of this Agreement by Genzyme pursuant to Section 12.3 and/or 12.5 that are necessary or useful (or, with respect to patent applications, would be necessary or useful if such patent applications were to issue as patents) for the Exploitation of a Licensed Product in the Field in the Territory.

ARTICLE 2

GRANT OF RIGHTS AND RELATED TRANSFER OBLIGATIONS

2.1    Grants to X4. Subject to Section 2.2, Section 2.3, Section 4.7 and the other terms and conditions of this Agreement, Genzyme hereby grants to X4:

2.1.1    an exclusive (including with regard to Genzyme and its Affiliates, excepting only the retained rights of Genzyme described in Section 2.2) license during the Term, with the right to grant sublicenses in accordance with Section 2.3, under the Licensed Patents and the Licensed Know-How to Exploit the Licensed Compounds and Licensed Products in the Field in the Territory.

2.1.2    a non-exclusive license during the Term, with the right to grant sublicenses in accordance with Section 2.3, to use any Trademark and/or logo of Genzyme or its Affiliates solely as necessary for X4 to perform its obligations under Section 4.6 and for no other purpose.

2.2    Retention of Rights and Negative Covenant by Genzyme.

2.2.1    Notwithstanding anything to the contrary in this Agreement, Genzyme retains, on behalf of itself and its Affiliates, the exclusive right in and to the Licensed Patents and the Licensed Know-How to Exploit Licensed Compounds and Licensed Products in the Territory outside of the Field and solely for use in Mozobil Indications, Allo-HSCT Treatments and Auto-HSCT Treatments; provided, that, the retained right of Genzyme to Exploit the Licensed Compounds and Licensed Products outside of the Field shall be subject, in each such case, to Section 2.2.2 and to the prior written consent of X4, which consent shall not be unreasonably withheld, delayed or conditioned.

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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2.2.2    Notwithstanding anything to the contrary in this Agreement, Genzyme retains, on behalf of itself and its Affiliates, the non-exclusive right in and to the Licensed Patents and the Licensed Know-How to conduct preclinical research, and testing with respect to the Licensed Compounds in the Field in the Territory, and to Manufacture the Licensed Compounds solely for use in the performance of such preclinical research and testing, subject to the remainder of this Section 2.2.2. For clarity, the foregoing rights shall exclude any clinical development or Commercialization of the Licensed Compounds of any kind in the Field and/or manufacture of the Licensed Compounds for such purpose. Genzyme further covenants that it will not, during the Term, engage in any clinical Development or Commercialization of any of the Licensed Compounds listed on Schedule 1.56 outside the Field (including in the Mozobil Indications, for Allo-HSCT Treatments and for Auto-HSCT Treatments) and/or manufacture of the Licensed Compounds listed on Schedule 1.56 for any such purpose. Any proposed publication by Genzyme or its Affiliates of research results relating to the Licensed Compounds that are obtained in the performance of the research activities described in this Section 2.2.2 shall be subject to the restrictions of Section 9.5 hereof.

2.3    Sublicenses.

2.3.1    The rights and licenses granted to X4 under Section 2.1 shall include the right to grant sublicenses, which shall not be further sublicensable, to its Affiliates, and to academic collaborators and Third Party contractors to Develop the Licensed Compounds and Licensed Products in the Field in the Territory; provided, that, X4 shall require each such Sublicensee to agree in writing to be bound by the applicable terms and conditions of this Agreement, including Section 4.7, Section 12.7, ARTICLE 7 and ARTICLE 9. No such sublicense shall relieve X4 of any of its obligations hereunder and X4 shall use its Commercially Reasonable Efforts to enforce compliance by each such Sublicensee to the extent such enforcement is required to allow X4 to comply with its obligations hereunder. X4 shall promptly inform Genzyme in writing of any material breach by a Sublicensee of its sublicense agreement to the extent such material breach would reasonably be expected to affect Genzyme’s rights under this Agreement, and any failure by X4 to promptly take reasonable steps in accordance with the terms of the sublicense to have Sublicensee remedy such material breach shall constitute a material breach of this Agreement.

2.3.2    Subject to X4’s compliance with its obligations under Section 4.7, and subject to X4 having secured the X4 First Financing as required under Section 12.1, the rights and licenses granted to X4 under Section 2.1 shall include the right to grant sublicenses to its Affiliates and Third Parties to Develop and/or Commercialize the Licensed Compound and Licensed Products in the Field in the Territory. X4 shall (a) require each Sublicensee to agree in writing to be bound by the applicable terms and conditions of this Agreement, including Section 4.7, Section 12.7, ARTICLE 7 and ARTICLE 9, and (b) provide Genzyme with a written notice of the execution of such sublicense (which written notice shall include a copy of any such sublicense)., which copy may be redacted by X4 with respect to obligations that are not relevant to X4’s obligations under this Agreement, the terms of which shall be Confidential Information of X4 and subject to Article 9. No such Sublicensee shall relieve X4 of any of its obligations hereunder and X4 shall use its Commercially Reasonable Efforts to enforce compliance by each such Sublicensee to the extent such enforcement is required to allow X4 to comply with its obligations hereunder. X4 shall promptly inform Genzyme in writing of any material breach by a Sublicensee of its

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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sublicense agreement to the extent such material breach would reasonably be expected to affect Genzyme’s rights under this Agreement, and any failure by X4 to promptly take reasonable steps in accordance with the terms of the sublicense to have Sublicensee remedy such material breach shall constitute a material breach of this Agreement.

2.4    Paid-Up License. Upon the expiration of the Royalty Term with respect to a Licensed Product in a country, the licenses granted to X4 under Section 2.1 shall become fully paid-up, irrevocable and perpetual for such Licensed Product in that country.

2.5    Genzyme Trademarks. With respect to any Trademark and/or logo of Genzyme or its Affiliates licensed to X4 under Section 2.1.2, X4 agrees to conform to the guidelines of Genzyme in effect from time to time (as notified in writing to X4) with respect to manner of use and to maintain the quality standards of Genzyme for goods sold and services provided in connection with any such Trademark and/or logo of Genzyme or its Affiliates. X4 and its Affiliates shall, and shall include in each Sublicense agreement an obligation of each Sublicensee to, use diligent efforts not to do any act that endangers, destroys or similarly affects the value of the goodwill pertaining to the any Trademark and/or logo of Genzyme or its Affiliates. X4 and its Affiliates shall, and shall include in each Sublicense agreement an obligation of each Sublicensee to, execute any documents required in the reasonable opinion of Genzyme to be entered as a “registered user” or recorded licensee of the any Trademark and/or logo of Genzyme or its Affiliates or to be removed as registered user or licensee thereof.

2.6    No Implied Rights. For the avoidance of doubt, X4, its Sublicensees and its and their respective Affiliates shall have no right, express or implied, with respect to the Licensed Patents, the Licensed Know-How or any Trademark and/or logo of Genzyme or its Affiliates, except as expressly provided in Section 2.1.

2.7    Disclosure. Genzyme shall use commercially reasonable efforts to deliver the Licensed Know-How to X4, at Genzyme’s sole cost and expense, within [***] after the Effective Date. Genzyme shall also provide to X4, where available, copies of any raw data from Clinical Studies, case report forms, protocols and amendments, trial master files and investigator brochures related to the Licensed Compound and the Licensed Products.

2.8    Initial Material Transfer. Within [***] after the Effective Date, Genzyme shall, at Genzyme’s sole cost and expense, deliver to X4 approximately the quantity of Licensed Compound in powder form as shown on Schedule 1.56 (the “Initial Materials”), and a “Certificate of Analysis” with respect to the Initial Materials and will transfer ownership to X4 of any Initial Materials (or work in-process of Initial Materials) currently housed at Aptuit (Genzyme’s contract manufacturer of AMD11070). X4 shall reimburse Genzyme for the reasonable out-of-pocket expenses incurred by Genzyme in delivering the Initial Materials to X4 pursuant to this Section 2.8. THE INITIAL MATERIALS SUPPLIED BY GENZYME UNDER THIS SECTION 2.8 ARE SUPPLIED “AS IS” AND GENZYME MAKES NO REPRESENTATIONS AND EXTENDS NO WARRANTIES OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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PURPOSE, OR THAT THE USE OF THE INITIAL MATERIALS DOES NOT INFRINGE ANY PATENT, COPYRIGHT, TRADEMARK, OR OTHER PROPRIETARY RIGHTS OF A THIRD PARTY. X4 assumes all liability for damages which may arise from its use, storage or disposal of the Initial Materials. Genzyme will not be liable to X4 for any loss, claim or demand made by X4, or made against X4 by any Third Party, due to or arising from the use of the Initial Materials except, to the extent permitted by applicable Laws, to the extent caused by the negligence or willful misconduct of Genzyme.

ARTICLE 3

DEVELOPMENT AND REGULATORY

3.1    Development.

3.1.1    Development Plans. The initial Development Plan, which covers the period from the Effective Date through the first Calendar Quarter of 2015, is attached to this Agreement as Schedule 3.1.2. [***], X4 shall prepare and submit an updated Development Plan to Genzyme. Each such update to the Development Plan shall set forth for the applicable Calendar Year the Development objectives, the planned Clinical Studies and other Development activities and the contemplated timelines for the foregoing. X4 shall manage the preparation of each such update so that it is submitted to Genzyme [***]. X4 shall consider in good faith any comments Genzyme may provide with respect to any such updates to the Development Plan.

3.1.2    Diligence. X4 shall use Commercially Reasonable Efforts to Develop, at is sole cost and expense, and obtain and maintain Regulatory Approvals for at least one Licensed Product for use in the Field in at least the USA and one of the other Major Markets.

3.2    Regulatory Matters.

3.2.1    Regulatory Responsibilities.

(a)    X4 shall have the sole right and responsibility for preparing, obtaining and maintaining Drug Approval Applications and any other Regulatory Approvals and other submissions, and for conducting communications with the Regulatory Authorities, for Licensed Products in the Field in the Territory. As between the Parties, all Drug Approval Applications and Regulatory Approvals relating to Licensed Products in the Field with respect to the Territory shall be owned by, and shall be the sole property and held in the name of, X4 or its designated Affiliate or Sublicensee.

(b)    Genzyme hereby assigns to X4 all of Genzyme’s right, title and interest in and to the Drug Approval Applications and Regulatory Approvals with respect to the Licensed Compound Controlled by Genzyme on the Effective Date (the “Assigned Regulatory Documentation”), a list of which Assigned Regulatory Documentation is set forth on Schedule 3.2.1. Promptly following the completion of X4 First Financing, Genzyme shall take such steps as may be reasonably necessary to promptly complete the transfer to X4 of its ownership of the Assigned Regulatory Documentation. All such Assigned Regulatory Documentation will be owned by and held in the name of X4.

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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(c)    Schedule 3.2.1(c) sets forth all Regulatory Documentation, other than the Assigned Regulatory Documentation, that is Controlled by Genzyme as of the Execution Date. Genzyme hereby grants to X4 the exclusive right, and right of reference, under Genzyme’s right, title, and interest in and to all such Regulatory Documentation not assigned to X4 pursuant to Section 3.2.1(b), to use such Regulatory Documentation for the purposes of seeking Regulatory Approvals to Commercialize Licensed Products in the Field in the Territory in accordance with this Agreement. X4 may sublicense such rights in connection with any sublicense granted in accordance with Section 2.3.

(d)    Genzyme shall, upon the written request of X4, notify the applicable Regulatory Authorities in writing that it is transferring responsibility for Regulatory Documentation, including the Assigned Regulatory Documentation, to X4, and X4 shall notify the applicable Regulatory Authorities in writing that it is accepting all regulatory responsibilities associated with such Regulatory Documentation (including the responsibility for reporting Adverse Events).

3.3    Reports. At least [***] commencing on the last day of the first full Calendar Year following the Effective Date and [***], X4 shall provide Genzyme with a detailed report describing (a) the Development activities it has performed, or caused to be performed, since the preceding report (including any filings, submissions, communications or meetings with any Regulatory Authorities) and (b) its Development activities in process (including any Clinical Data and Patent filings) and (c) safety findings related to the Licensed Compounds and Licensed Products. All information disclosed by X4 to Genzyme pursuant to this Section 3.3 shall be the Confidential Information of X4.

3.4    Records. X4 shall maintain, or cause to be maintained, all Regulatory Documentation Controlled by X4 and final supporting records and documentation therefor (but not draft records or documentation therefor except as otherwise required by Applicable Law), in sufficient detail and in compliance with Applicable Law. Such records and documentation shall be complete and accurate and shall fully and properly reflect all work done and results achieved in the performance of the applicable Development activities in a manner appropriate for any regulatory purpose and, when applicable, for use in connection with Patent filings, prosecution and maintenance. Such records and documentation shall be retained by X4 for [***].

3.5    Subcontracting. X4 may subcontract the exercise of its rights and the performance of its obligations under this ARTICLE 3; provided, that, (a) X4 shall oversee the performance by its subcontractors of the subcontracted activities in a manner that would be reasonably expected to result in their timely and successful completion and (b) any agreement pursuant to which X4 engages a subcontractor pursuant to this Section 3.5 must (i) be consistent with this Agreement and (ii) contain terms obligating such subcontractor to: (A) comply with confidentiality provisions that are consistent with those set forth in ARTICLE 9; and (B) provide Genzyme with substantially the same rights with respect to any Information, Patents and other intellectual property arising from the performance of the subcontracted obligation as Genzyme would have under this Agreement if such Information, Patents or other intellectual property had arisen from the performance of such obligation by X4.

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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3.6    Compliance. X4 shall perform or cause to be performed any and all of its Development activities under this Agreement in a good scientific manner and in compliance with all Applicable Law.

3.7    Regulatory Audits. During the period commencing on the Effective Date and continuing until the first to occur of the expiration of the Term, the termination of this Agreement or the consummation of a Transaction, Genzyme shall have the right, during normal business hours and upon reasonable notice, to inspect any regulatory records and correspondence kept by X4, its Affiliates or Sublicensees in accordance with this Article 3. Any such audit may not be conducted more than [***]. The cost of any audit shall be borne by Genzyme. Notwithstanding the foregoing, to the extent that X4 does not have the right to grant Genzyme the right to audit the records of any of its Sublicensees hereunder, X4 shall obtain for itself such right and, at Genzyme’s request, X4 shall, subject to the limitations set forth in this Section 3.7, exercise such audit right with respect to such Sublicensees and shall provide the results of such audit to Genzyme.

ARTICLE 4

COMMERCIALIZATION

4.1    Commercialization. Subject to Section 4.7, X4 shall have the sole right, at is sole cost and expense, to control the Commercialization of Licensed Products in the Field in the Territory.

4.2    Commercial Diligence. X4 shall use Commercially Reasonable Efforts to Commercialize at least one Licensed Product in the Field in accordance with Applicable Law in each of the USA and at least one of the other Major Markets.

4.3    Compliance with Applicable Law. X4 and its Affiliates shall, and X4 shall include in each Sublicense agreement an obligation of each Sublicensee to, comply with all Applicable Law with respect to the Commercialization of the Licensed Products.

4.4    Sales and Distribution. X4 shall be solely responsible for invoicing and booking sales, establishing all terms of sale (including pricing and discounts) and warehousing and distributing the Licensed Products in the Field in the Territory and shall perform such activities in accordance with the terms and conditions of this Agreement. X4 shall be solely responsible for handling all returns, recalls and withdrawals, order processing, invoicing and collection, distribution and inventory and receivables with respect to the Licensed Product in the Field in the Territory.

4.5    Product Trademarks. X4 shall have the right to determine and own the Product Trademarks to be used with respect to the Exploitation of the Licensed Products in the Field in the Territory.

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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4.6    Markings. To the extent required by Applicable Law in a country in the Territory, the promotional materials, packaging and Product Labeling for the Licensed Product used by X4, its Sublicensees or its or their respective Affiliates in connection with the Licensed Product in such country shall contain (a) the Genzyme Corporate Name and (b) the logo and corporate name of the manufacturer (collectively, the “Markings”). The manner in which the Markings are to be presented on promotional materials, packaging and Product Labeling for the Licensed Product shall be subject to Section 2.5 and Section 7.1.2.

4.7    Genzyme Right of First Negotiation. Genzyme shall have a right of first negotiation, as described in this Section 4.7, to negotiate with X4 for an agreement providing rights for the grant to Genzyme or its Affiliates of the right to Exploit Licensed Products in the Field in the Territory (the “Right of First Negotiation”). If at any time during the Term, X4 determines, in its sole discretion, that it wishes to seek to grant a sublicense (an “Out-License”) under the Licensed Patents and/or Licensed Know-How to a Third Party for the Development and/or Commercialization of any Licensed Product, then X4 will notify Genzyme in writing and provide a non-confidential summary of the Licensed Product that is the subject of the proposed Out-License, as well as the intended scope (i.e., field and territory) of the Out-License (a “Trigger Notice”). If Genzyme desires to evaluate such Out-License, Genzyme will provide X4 with a written notice of same [***] that provides the process and time lines for internal diligence and stage gate committee meetings that are required to advance into license negotiations (a “Negotiation Notice”). Promptly after X4’s receipt of a Negotiation Notice, X4 will provide Genzyme with a confidential summary of the Licensed Product (each, a “Data Package”), including material Clinical Data and preclinical data Controlled by X4 (as well as such other information in X4’s Control that Genzyme may reasonably request), which Data Package shall be Confidential Information of X4 under this Agreement. During the period commencing on the date of receipt by X4 of the Negotiation Notice [***] (the “Diligence Period”), Genzyme will complete its diligence and comply with the time lines set in the Negotiation Notice and Genzyme and X4 shall have weekly meetings (either in person or by phone) to discuss Genzyme’s progress and to answer any questions related to diligence. During the period commencing on the last day of the Diligence Period [***] (the “Exclusivity Period”), Genzyme will have an exclusive right to negotiate with X4 for an exclusive, royalty-bearing license to such Licensed Product in the field and territory specified in the Trigger Notice. If (a) Genzyme (i) does not deliver a Negotiation Notice to X4 within the [***], (ii) does not deliver a binding written proposal to X4 for the terms of an Out-License to X4 during the Exclusivity Period, or (iii) declines in writing an Out-License to the Licensed Product after review of the Data Package, or (b) Genzyme and X4 do not mutually agree on the terms of an Out-License within the Exclusivity Period, Genzyme shall have no further rights under this Agreement with respect to such Licensed Product and X4 will be free to negotiate an Out-License for such Licensed Product with any Third Party, subject to the terms of Section 2.2 (Sublicenses).

4.8    Subcontracting. Subject to Section 4.7, X4 may subcontract the Commercialization of the Licensed Products in the Field in the Territory; provided, that, (a) X4 shall use its Commercially Reasonable Efforts to oversee the performance by its subcontractors of the subcontracted activities in a manner that would be reasonably expected to result in their timely and successful completion of such activities and (b) any agreement

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

19

pursuant to which X4 engages a subcontractor must (i) be consistent in all material respects with this Agreement and (ii) contain terms obligating such subcontractor to comply with confidentiality provisions that are at least as restrictive as those set forth in ARTICLE 9. For clarity, the foregoing shall not limit X4’s right to grant Sublicenses pursuant to Section 2.3 and, subject to the requirements of Section 2.3, X4 shall have the right to exercise its rights and fulfill its obligations through one or more Affiliates or Sublicensees.

ARTICLE 5

MANUFACTURE AND SUPPLY

5.1    In General. X4 shall (a) be responsible for the Manufacture of Licensed Compounds and each Licensed Product in sufficient quantities to enable X4 to pursue the Exploitation of such Licensed Product in the Field in the Territory in accordance with its obligations under Section 4.12, and (b) use Commercially Reasonable Efforts to assure an efficient and reliable supply of Licensed Compounds and each Licensed Product conforming to the applicable specifications with respect thereto as necessary to Exploit and maintain Regulatory Approvals for such Licensed Product in the Field in the Territory in accordance with its obligations under Section 4.2 and Section 3.32, including developing commercially reasonable arrangements and strategies for back-up sources of supply of such Licensed Compounds and Licensed Product that appropriately and reasonably minimize the risk of supply shortfalls and that take into account expected inventory levels and demand.

5.2    Subcontracting of Manufacturing Rights. In furtherance of the obligations set forth in Section 5.1, X4 shall either itself Manufacture and supply, or may enter into one or more definitive Manufacturing and supply agreements with Genzyme or Third Parties to Manufacture and supply, clinical and commercial supplies of Licensed Compounds and each Licensed Product. X4 shall, shall cause its Affiliates to, and shall include in any agreement with any Third Party that Manufactures and supplies clinical or commercial supplies of Licensed Compounds and any Licensed Product an obligation of such Third Party to, comply with all Applicable Law with respect to the Manufacture of Licensed Compound and Licensed Products.

ARTICLE 6

PAYMENTS

6.1    Signature Fee. No later than ten (10) days after the Execution Date, X4 shall pay Genzyme an upfront amount equal to [***]. Such payment shall be nonrefundable (including in the case that this Agreement would not enter into force as per Section 12.1) and non-creditable against any other payments due hereunder.

6.2    X4 First Financing Fee. No later than thirty (30) days after the closing of the X4 First Financing, X4 shall pay Genzyme an upfront amount equal to Three Hundred Thousand Dollars ($300,000). Such payment shall be nonrefundable and non-creditable against any other payments due hereunder.

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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6.3    Equity Consideration.

6.3.1    Unit Issuance.

(a)    Initial Grant. [***] after the closing of the X4 First Financing, X4 shall issue to Genzyme or to Genzyme’s designated Affiliate a number of units of ownership interests of X4 (“Units”) that represents, on an as-converted basis, ten per cent (10%) of the outstanding Units of X4 immediately following the closing of the X4 First Financing (the “Initial Units”).

(b)    Anti-Dilution Grant. If at any time prior to the date of [***], X4 issues Units (including any options, warrants or rights to purchase or acquire Units from X4) that would cause Genzyme’s percentage ownership in X4 to drop below ten percent (10%), X4 shall issue additional Units to Genzyme to restore Genzyme’s percentage ownership in X4 to ten percent (10%) (the “Anti-Dilution Units”). The obligation of X4 to issue Anti-Dilution Units shall terminate on the date of Financial Commitment.

(c)    Execution of Documents. Concurrently with such issuance of the Initial Units and/or the issuance of the Anti-Dilution Shares, Genzyme shall or shall cause its designated Affiliate to execute and deliver to X4 and the Third Party investors in X4 customary documents (such as, without limitation, a restricted unit purchase agreement, an investor rights agreement and a voting agreement).

6.3.2    Put Option.

(a)    Put Option. At any time during the Term, Genzyme or its Affiliate, as the holder of Units of X4, will have the one time right to request in writing that X4 purchase all (but not less than all) of the Units of X4 then held by Genzyme or such Affiliate (the “Subject Units”). Upon X4’s receipt of such written notice, X4 shall purchase such Subject Units from Genzyme or such Affiliate, for a purchase price equal to [***] (the “Purchase Price”).

(b)    Put Closing.

(i)    The closing of the purchase and sale of any Subject Units (each a “Put Closing”) shall take place on, and payment therefor shall be made in full on, the date that is [***] after the notice from Genzyme pursuant to Section 6.3.2(a) exercising the right to require X4 to purchase Subject Units (the “Put Closing Date”). The Put Closing shall take place at 10:00 a.m. on the Put Closing Date.

(ii)    The Purchase Price shall be paid in full by X4 at the Put Closing, by wire transfer of immediately available federal funds or by bank cashier’s or certified check , and Genzyme shall deliver the Subject Units to be sold to X4 at Closing duly endorsed for transfer to X4, which Subject Units shall be, and upon the request of X4, Genzyme shall provide to X4 a certificate to the effect that, the Subject Units being sold are free and clear of all liens and encumbrances of any kind, nature and description other than applicable restrictions under federal and state securities laws.

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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6.4    Milestones.

6.4.1    Regulatory Milestone Payments. X4 shall pay Genzyme the following one-time, non-refundable, non-creditable milestone payments [***] after the first achievement of the corresponding Milestone Event by X4, its Sublicensees or their respective Affiliates:

6.4.2    Sales Milestone Payment. X4 shall pay Genzyme the following one-time, non-refundable, non-creditable milestone payments [***] after the first achievement of the corresponding Milestone Event by X4, its Sublicensees and their respective Affiliates:

6.4.3    Milestone Payment upon Change of Control. X4 shall pay to Genzyme a one-time, non-refundable, non-creditable milestone payment upon the closing during the Term of any transaction that constitutes a Change of Control (the “Transaction”), in an amount equal to five and half of one percent (5.5%) of the Net Consideration paid or payable to all X4’s equity holders (including Genzyme) less the amount of Net Consideration that Genzyme (and its Affiliates, assignees and/or transferees) is entitled to receive in connection with the Transaction by reason of the ownership by any of them of shares of ownership interests of X4 (including securities, warrants, stock appreciation rights, options or similar rights, whether or not vested, that are convertible into ownership interests of X4). The milestone payment described in this Section 6.4.3 shall become due and payable as from the date on which X4’s equity holders actually receive

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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the consideration owed to them under the Transaction and, for clarity, no payment under this Section 6.4.3 will be due by X4 to Genzyme with respect to any consideration resulting from a deferred payment under the Transaction until such deferred payment is made to X4’s equity holders. For the purpose of this Section 6.4.3, “Net Consideration” shall mean [***]. If Genzyme reasonably disagrees with the calculation of the Net Consideration provided by X4 it shall provide X4 with written notice [***] of its receipt of the calculation provided by X4. To the extent that parties are unable to resolve the disagreement [***], the matter shall be resolved in accordance with Section 6.12.

6.4.4    Determination that Milestone Events Have Occurred. X4 shall notify Genzyme promptly of the achievement of each Milestone Event. In the event that, notwithstanding the fact that X4 has not provided Genzyme such a notice, Genzyme believes that any such Milestone Event has been achieved, it shall so notify X4 in writing and the Parties shall promptly meet and discuss in good faith whether such Milestone Event has been achieved. Any dispute under this Section 6.4.3 regarding whether or not a Milestone Event has been achieved shall be subject to resolution in accordance with Section 13.5.

6.4.5    No Multiple Payments. For purposes of clarity, in the event that any milestone event set forth in Section 6.4.1 and/or Section 6.4.2 is achieved by a Sublicensee, X4 shall be obligated to pay to Genzyme the applicable milestone payment contemplated by Section 6.4.1 or Section 6.4.2, as the case may be, but shall not be obligated to pay Genzyme the Sublicense Percentage of any such milestone payment received by X4 from such Sublicensee.

6.5    Royalties.

6.5.1    Royalty Rates. X4 shall pay Genzyme a royalty on Net Sales of all Licensed Products in the Territory (excluding Net Sales of each Licensed Product in any country in the Territory for which the Royalty Term for such Licensed Product and country has expired) in each Calendar Year (or partial Calendar Year) at the tiered rates set forth in the table below:

6.5.2    Blended Royalty. X4 acknowledges that (a) the Licensed Know-How and the Information included in the Regulatory Documentation licensed by Genzyme to X4 are proprietary and valuable and that without the Licensed Know-How and such Information, X4 may not be able to obtain and maintain Regulatory Approvals with respect to the Licensed Products, (b) such Regulatory Documentation may allow X4 to obtain and maintain Regulatory Exclusivity

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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with respect to the Licensed Products in the Field in the Territory, and (c) the milestone payments and royalties set forth in Section 6.4 and this Section 6.5, respectively, are, in part, intended to compensate Genzyme for the value of such exclusivity. The Parties agree that the royalty rates set forth in this Section 6.5 reflect an efficient and reasonable blended allocation of the value provided by Genzyme to X4.

6.5.3    Royalty Reduction.

(a)    If X4 or any of its Affiliates, is required to pay a Third Party amounts with respect to a Licensed Product in any country under a written agreement under which X4 or its Affiliate obtains a license under or acquires a Patent Controlled by such Third Party that contains a Valid Claim that covers such Licensed Product in such country, X4 may provide written notice to Genzyme setting forth in reasonable detail the identity of such Third Party and such Third Party Patent (which written notice shall include a copy of any such license or acquisition agreement entered into by X4 or its Affiliate as applicable, including its financial terms) and, thereafter, X4 may deduct [***]. Notwithstanding the foregoing, [***].

(b)    In the event a Licensed Product is sold in a country and is not covered by a Valid Claim in that country, the tiered royalty rates payable by X4 to Genzyme under Section 6.5.1 shall be reduced by [***] during the applicable Royalty Term with respect to that country.

(c)    Generic Products. In the event that one or more Third Parties sell a Generic Product (as defined below) in any country in which a Licensed Product is then being sold by X4, then, (a) during any Calendar Quarter in which sales of the Generic Product by such Third Parties are equal to or greater than [***] (as measured by prescriptions or other similar information available from a Third Party data provider reasonably acceptable to the Parties and applicable to such country) the applicable royalties in effect with respect to such Licensed Product in such country as specified in Section 6.5.1 shall be reduced [***] and (b) during any Calendar Quarter in which sales of the Generic Product by such Third Parties are [***] (as measured by prescriptions or other similar information available from a Third Party data provider reasonably acceptable to the Parties and applicable to such country) the applicable royalties in effect with respect to such Licensed Product in such country as specified in Section 6.5.1 shall be reduced [***]. For purposes of this Section 6.5.3(c), a “Generic Product” means [***].

6.5.4    Payment Dates and Reports. Royalty payments shall be made by X4 [***] after the end of each Calendar Quarter commencing with the Calendar Quarter in which the first day of the first Royalty Term for the first Licensed Product occurs. X4 shall also provide to Genzyme, at the same time each such payment is made, a report showing: (a) the Invoiced Sales of Licensed Products by country (in the local currency) in the Territory and the Net Sales of Licensed Products by country (in Dollars); (b) the basis for any deductions from Invoiced Sales to determine Net Sales; (c) the applicable royalty rates for the Licensed Products; (d) the exchange rates used in calculating any of the foregoing; and (e) a calculation of the amount of royalty due to Genzyme.

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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6.6    Sublicense Revenue. X4 shall pay to Genzyme the applicable Sublicense Percentage of any Sublicense Revenue paid to X4 or any of its Affiliates in connection with any Sublicense.

6.7    Mode of Payment; Currency Conversion.

(a)    All payments to Genzyme under this Agreement shall be made by electronic funds transfer of Dollars in the requisite amount to such bank account as Genzyme may from time to time designate by written notice to X4.

(b)    If any currency conversion shall be required in connection with any payment hereunder, such conversion shall be made by using the arithmetic mean of the exchange rates for the purchase of Dollars as published in The Wall Street Journal, Eastern Edition, on the last Business Day of each month in the Calendar Quarter to which such payments relate.

6.8    Taxes. Genzyme alone shall be responsible for paying any and all income taxes (other than withholding taxes required by Applicable Law to be paid by X4) levied on account of, or measured in whole or in part by reference to, any milestones and other amounts payable by X4 to Genzyme pursuant to this Agreement (“Payments”) it receives. X4 shall deduct or withhold from the Payments any taxes that it is required by Applicable Law to deduct or withhold. Notwithstanding the foregoing, if Genzyme or any of its Affiliates is entitled under any applicable tax treaty to a reduction of rate of, or the elimination of, applicable withholding tax, it may deliver to X4 or the appropriate governmental authority (with the assistance of X4) the prescribed forms (including the US Tax Residency Form 6166 or IRS Form W-8BEN-E) necessary to reduce the applicable rate of withholding or to relieve X4 of its obligation to withhold tax, and X4 shall apply the reduced rate of withholding, or dispense with withholding, as the case may be; provided that X4 has received from Genzyme delivery of all applicable forms (and, if necessary, its receipt of appropriate governmental authorization) at least fifteen (15) days prior to the time that the Payments are due. X4 shall notify Genzyme if X4 intends to withhold at least thirty (30) days prior to the time the Payments are due. If, in accordance with the foregoing, X4 withholds any amount, it shall pay to Genzyme the balance when due, make timely payment to the proper taxing authority of the withheld amount and send to Genzyme proof of such payment within fifteen (15) days following such payment.

6.9    Interest on Late Payments. If any Payment due to Genzyme under this Agreement is not paid in when due, then X4 shall pay interest on the unpaid amount and on any unpaid accrued interest (before and after any judgment) at an annual rate (but with interest accruing on a daily basis) of [***], or the maximum rate permitted by Applicable Laws, whichever is less, such interest to run from the date upon which payment of such amount became due until payment thereof in full together with such accrued interest.

6.10    Financial Records. X4 and its Affiliates shall, and X4 shall include in each of its Sublicense agreements an obligation of such Sublicensees to, keep complete and accurate books and records that are necessary to verify the milestone and royalty payments owed under Section 6.4 and Section 6.5, including books and records of Invoiced Sales

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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(including any deductions therefrom) and Net Sales of Licensed Products in the Territory. X4 and its Affiliates shall, and X4 shall include in each of its Sublicense agreements an obligation of such Sublicensee to, retain such books and records, until the later of [***], or for such longer period as may be required by Applicable Law.

6.11    Audit. At the request of Genzyme, X4 and its Affiliates shall, and X4 shall include in each of its Sublicense agreements an obligation of such Sublicensee to, permit an independent certified public accountant retained by Genzyme, at reasonable times and upon reasonable notice, to audit the books and records maintained pursuant to Section 6.10. In no event shall such independent certified public accountant disclose to Genzyme any information other than its findings regarding the accuracy of the reports and payments made by X4 under this Article 6. Such audits may not (a) be conducted for any Calendar Quarter [***], (b) be conducted [***] (unless a previous audit during such [***] revealed an underpayment with respect to such period or X4 restates or revises such books and records for such [***]) or (c) be repeated for any Calendar Quarter. Except as provided below, the cost of any audit shall be borne by Genzyme, unless the audit reveals [***], in which case X4 shall bear the cost of the audit. Unless disputed pursuant to Section 6.12, (a) if such audit concludes that additional payments were due and payable by X4, X4 shall pay the additional amounts, with interest from the date originally due as provided in Section 6.9 within thirty (30) days after the date on which such audit is completed and the conclusions thereof are notified to the Parties and (b) if such audit concludes that X4 overpaid Genzyme, [***]. Notwithstanding the foregoing, to the extent that X4 does not have the right to grant Genzyme the right to audit the records of any of its Sublicensees hereunder, X4 shall obtain for itself such right and, at Genzyme’s request in accordance with the third sentence of this Section 6.11, X4 shall exercise such audit right with respect to such Sublicensees, using an independent certified public account reasonably acceptable to Genzyme, and shall provide the results of such audit to Genzyme.

6.12    Audit Dispute. In the event of a dispute over the results of any audit conducted pursuant to Section 6.11, Genzyme and X4 shall work in good faith to resolve such dispute. If the Parties are unable to reach a mutually acceptable resolution of any such dispute [***], the dispute shall be submitted for arbitration to a certified public accounting firm selected by each Party’s certified public accountants or to such other Person as the Parties shall mutually agree (the “Accountant”) or failing such agreement, as the Chairman of the International Chamber of Commerce (or such other body as the Parties may mutually agree), may nominate. The decision of the Accountant shall be final and the costs of such arbitration as well as the initial audit shall be borne between the Parties in such manner as the Accountant shall determine.

6.13    Confidentiality. Genzyme shall treat all information subject to review under this ARTICLE 6 in accordance with the confidentiality provisions of ARTICLE 9 and Genzyme shall cause the independent public accountant retained by Genzyme pursuant to Section 6.11 or the Accountant, as applicable, to enter into a reasonably acceptable confidentiality agreement that includes an obligation to retain all such financial information in confidence and to disclose to Genzyme solely its findings regarding the accuracy of the reports and payments made by X4 hereunder, and not any other such financial information.

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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ARTICLE 7

INTELLECTUAL PROPERTY

7.1    Ownership of Intellectual Property.

7.1.1    Ownership of Technology. Subject to the licenses granted under Section 2.1, as between the Parties, each Party shall own and retain all right, title and interest in and to any and all: (a) Information that is conceived, discovered, developed or otherwise made by or on behalf of such Party, its (sub)licensees or its and their respective Affiliates under or in connection with this Agreement, whether or not patented or patentable, and any and all Patents and other intellectual property rights with respect thereto and (b) other Information, Patents and other intellectual property rights that are owned or otherwise Controlled (other than pursuant to the license grants set forth in Section 2.1) by such Party, its (sub)licensees or its and their respective Affiliates. The determination of authorship, inventorship or ownership of any Information that is conceived, discovered, developed or otherwise made under or in connection with this Agreement shall be made under United States Applicable Law, irrespective of where such Information is actually conceived, discovered, developed or otherwise made.

7.1.2    Ownership of any Trademark and/or logo of Genzyme or its Affiliates. As between the Parties, Genzyme shall retain all right, title and interest in and to the any Trademark and/or logo of Genzyme or its Affiliates.

7.2    Patent Prosecution.

7.2.1    Filing, Prosecution and Maintenance. [***], X4 shall control and use Commercially Reasonable Efforts in conducting the preparation, filing, prosecution and maintenance (including with respect to any related interference, re-issuance, re-examination, post-grant review and opposition proceedings) (“Prosecution and Maintenance”) of the Licensed Patents in the Territory at its sole cost and expense using counsel reasonably acceptable to Genzyme; provided that (a) [***] and (b) if X4 plans to abandon any Licensed Patent in a country or region, then X4 shall notify Genzyme in writing [***], the term “Licensed Patents” automatically shall be modified to exclude the patent or patent application excluded in Licensed Patents in such country or territory as of the date X4 provides such written request to Genzyme., and Genzyme shall have the option, but not the obligation, to assume the Prosecution and Maintenance of such Patent in the specific country or territory at its sole cost and expense.

7.2.2    Cooperation. Each Party shall assist the other Party at the reasonable request of the other Party from time to time in connection with its activities set forth in Section 7.1.1 or Section 7.2.1, as applicable. X4 shall keep Genzyme reasonably informed, not less often that once per Calendar Year, of key steps to be taken in the Prosecution and Maintenance of all the Licensed Patents, including all applications filed by it pursuant to Section 7.2.1. Upon Genzyme’s written request, X4 shall furnish Genzyme with copies of such applications for Licensed Patents, amendments thereto and other related correspondence to and from patent offices, and, to the extent reasonably practicable, permit Genzyme an opportunity to offer its comments thereon before making a submission to a patent office, and X4 shall consider in good faith Genzyme’s comments.

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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7.2.3    Patent Term Extensions. X4 shall have the right to control decisions regarding patent term extensions, including supplementary protection certificates and any other extensions that are now or become available in the future, wherever applicable, for the Licensed Patents in any country in the Territory. X4 shall have the right and shall use Commercially Reasonable Efforts to pursue such extensions in accordance with such decisions. Genzyme shall use commercially reasonable efforts to provide prompt and reasonable assistance, as reasonably requested by X4, including by taking such action as Licensed Patent holder as is required under any Applicable Law to obtain any such extension.

7.2.4    CREATE Act. Notwithstanding anything to the contrary in this Section 7.2, neither Party shall have the right to make an election under the Cooperative Research and Technology Enhancement Act of 2004, 35 U.S.C. 103(c)(2)-(c)(3) (the “CREATE Act”) when exercising its rights under this Section 7.2 without the prior written consent of the other Party. With respect to any such permitted election, the Parties shall use reasonable efforts to cooperate and coordinate their activities with respect to any submissions, filings or other activities in support thereof. The Parties acknowledge and agree that this Agreement is a “joint research agreement” as defined in the CREATE Act.

7.3    Enforcement of Patents.

7.3.1    Notice. In the event either Party becomes aware of (a) any suspected infringement of any Licensed Patents or (b) any certification filed under the Hatch-Waxman Act claiming that any Licensed Patents are invalid or unenforceable or claiming that any Licensed Patents would not be infringed by the making, use, offer for sale, sale or import of a product for which an application under the Hatch-Waxman Act is filed, or any equivalent or similar certification or notice in any other jurisdiction in the Territory (each of clauses (a) and (b), an “Infringement”), such Party shall promptly notify the other Party and provide it with all details of such Infringement of which it is aware (each, an “Infringement Notice”); provided that each Party shall give the other Party an Infringement Notice [***].

7.3.2    Control of Enforcement. X4 shall have the first right, but not the obligation, through counsel of its choosing, to initiate an infringement action with respect to any Infringement of any Licensed Patents at its sole cost and expense or, subject to Section 2.3, to grant the infringing Third Party adequate rights and licenses necessary for continuing such activities. If X4 does not initiate such an infringement action [***] of learning of such Infringement, or earlier notifies Genzyme in writing of its intent not to so initiate an action, and X4 has not granted such infringing Third Party rights and licenses to continue its otherwise infringing activities, then Genzyme shall have the right, but not the obligation, to bring such an action; provided that, except with respect to any Infringement described in clause (b) of the definition thereof, if [***].

7.3.3    Settlement. The Party that controls the prosecution of a given Infringement claim pursuant to Section 7.3.2 shall also have the right to control settlement of such claim; provided that no settlement shall be entered into without the prior consent of the other Party if such settlement would adversely affect or diminish the rights and benefits of the other Party under this Agreement, or impose any new obligations or adversely affect any obligations of the other Party under this Agreement.

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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7.3.4    Cooperation. In the event a Party is entitled to and brings an infringement action in accordance with this Section 7.3, the other Party shall cooperate fully, including being joined as a party plaintiff in such action, providing access to relevant documents and other evidence and making its employees available at reasonable business hours, at the expense of the Party bringing the infringement action. If a Party pursues an action against such alleged Infringement, it shall consider in good faith any comments from the other Party and shall keep the other Party reasonably informed of any steps taken to preclude such infringement.

7.3.5    Costs and Recovery. The costs and expenses relating to any Infringement action commenced pursuant to this Section 7.3 shall be the responsibility of the Party controlling the prosecution thereof. Any damages or other amounts collected shall be [***].

7.4    Infringement Claims by Third Parties.

7.4.1    Defense of Third Party Claims. If a Third Party asserts that a Patent or other intellectual property right owned or otherwise controlled by it is infringed by the Exploitation of the Licensed Products in the Field in the Territory, the Party first made aware of such a claim shall promptly provide the other Party written notice of such claim along with the related facts in reasonable detail. X4 shall have the first right, but not the obligation, to control the defense of such claim. If X4 fails to assume control of the defense of such claim [***], then Genzyme shall have the right, but not the obligation, to defend against such claim. Notwithstanding the foregoing, the Party controlling such defense (the “Controlling Party”) shall not be entitled to assert a claim or counterclaim against such Third Party based on the Patents or other intellectual property rights owned or otherwise controlled by the other Party (the “Non-Controlling Party”) without the prior written consent of the Non-Controlling Party, such consent not to be unreasonably conditioned, withheld or delayed. The Non-Controlling Party shall cooperate with the Controlling Party, at the Controlling Party’s reasonable request and expense, in any such defense and shall have the right, at its own expense, to be represented separately by counsel of its own choice in any such proceeding.

7.4.2    Settlement of Third Party Claims. The Controlling Party with respect to a particular claim pursuant to Section 7.4.1 also shall have the right to control settlement of such claim; provided that [***].

7.4.3    Allocation of Costs. All costs and expenses relating to any defense, settlement and judgments in an action commenced pursuant to this Section 7.4 shall be borne by the Controlling Party with respect to such action.

7.5    Invalidity or Unenforceability Defenses or Actions.

7.5.1    Third Party Defense or Counterclaim.

(a)    If a Third Party asserts, as a defense or as a counterclaim in any infringement action under Section 7.3 or claim or counterclaim asserted under Section 7.4, or in a

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

29

declaratory judgment action or similar action or claim filed by such Third Party, that any Licensed Patent is invalid or unenforceable, then the Party pursuing such infringement action, or the Party first obtaining knowledge of such declaratory judgment action, as the case may be, shall promptly give written notice to the other Party.

(b)    X4 shall have the first right, but not the obligation, through counsel of its choosing, at its sole cost and expense, to defend against such action or claim. If X4 [***], Genzyme shall have the right, through counsel of its choosing, at its sole cost and expense, to defend against such action or claim.

7.5.2    Assistance. Each Party shall assist and cooperate with the other Party as such other Party may reasonably request from time to time in connection with its activities set forth in Section 7.5.1, including by providing access to relevant documents and other evidence and making its employees available at reasonable business hours; provided that neither Party shall be required to disclose legally privileged information unless and until procedures reasonably acceptable to such Party are in place to protect such privilege. In connection with any such defense or claim or counterclaim, the controlling Party shall consider in good faith any comments from the other Party and shall keep the other Party reasonably informed of any steps taken, and shall provide copies of all documents filed, in connection with such defense, claim or counterclaim. In connection with the activities set forth in Section 7.5.1, each Party shall consult with the other as to the strategy for the defense of the Licensed Patents.

7.6    Third Party Licenses. If, in the reasonable opinion of counsel to X4, the Exploitation of the Licensed Product in the Field in the Territory by X4, its Sublicensees or its or their respective Affiliates infringes or misappropriates any Patent or any intellectual property right of a Third Party in any country or countries in the Territory, [***], then X4 shall have the first right, but not the obligation, to negotiate the terms of a license from such Third Party in the applicable country or, countries in the Territory. X4 shall keep Genzyme regularly informed in writing of any such decision to enter into negotiation, and of the outcome thereof. [***].

7.7    Product Trademarks.

7.7.1    Maintenance and Prosecution of Product Trademarks. X4 shall own all right, title, and interest to the Product Trademarks in the Territory, and shall be responsible for the registration, prosecution, and maintenance thereof. All costs and expenses of registering, prosecuting, and maintaining the Product Trademarks shall be borne solely by X4.

7.7.2    Enforcement of Product Trademarks. X4 shall have the right and responsibility for taking such action as X4 deems necessary against a Third Party based on any alleged, threatened, or actual infringement, dilution, misappropriation, or other violation of, or unfair trade practices or any other like offense relating to, the Product Trademarks by a Third Party in the Territory. X4 shall bear the costs and expenses relating to any enforcement action commenced pursuant to this Section 7.7.2 and any settlements and judgments with respect thereto, and shall retain any damages or other amounts collected in connection therewith.

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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7.7.3    Third Party Claims. X4 shall have the right and responsibility for defending against any alleged, threatened, or actual claim by a Third Party that the use or registration of the Product Trademarks in the Territory infringes, dilutes, misappropriates, or otherwise violates any Trademark or other right of such Third Party or constitutes unfair trade practices or any other like offense, or any other claims as may be brought by a Third Party against a Party in connection with the use of the Product Trademarks with respect to a Licensed Product in the Territory. X4 shall bear the costs and expenses relating to any defense commenced pursuant to this Section 7.7.3 and any settlements and judgments with respect thereto, and shall retain any damages or other amounts collected in connection therewith.

7.7.4    Notice and Cooperation. Each Party shall provide to the other Party prompt written notice of any actual or threatened infringement of the Product Trademarks in the Territory and of any actual or threatened claim that the use of the Product Trademarks in the Territory violates the rights of any Third Party. Each Party shall cooperate fully with the other Party with respect to any enforcement action or defense commenced pursuant to this Section 7.7; provided that X4 shall bear the reasonable and documented out-of-pocket costs and expenses incurred by Genzyme in connection with such cooperation.

ARTICLE 8

PHARMACOVIGILANCE AND SAFETY

8.1    Global Safety Database. X4 shall set up, hold, and maintain (at X4’s sole cost and expense) the global safety database for the Licensed Products in the Territory.

8.2    Clinical Trial Register. Notwithstanding anything in this Agreement to the contrary, including ARTICLE 9, X4 shall have the right to disclose on publicly-accessible clinical trial registries the results or summaries of the results of all Clinical Studies for the Licensed Compound or Licensed Products conducted by or under authority of X4 in the Territory or as otherwise required by Applicable Law.

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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ARTICLE 9

CONFIDENTIALITY AND NON-DISCLOSURE

9.1    Confidentiality Obligations. At all times during the Term [***], each Party shall, and shall cause its Affiliates and, in the case of X4 as the Receiving Party, shall include in each Sublicense agreement an obligation of its Sublicensees to and its and their respective officers, directors, employees and agents to, keep completely confidential and not publish or otherwise disclose and not use, directly or indirectly, for any purpose, any Confidential Information furnished or otherwise made known to it, directly or indirectly, by the other Party, except to the extent such disclosure or use is expressly permitted by the terms of this Agreement or such use is reasonably necessary for the performance of its obligations or the exercise of its rights under this Agreement. “Confidential Information” means any information provided by one Party (the “Disclosing Party”) to the other Party (the “Receiving Party”) under or in connection with this Agreement, including the terms of this Agreement or any information relating to the Licensed Products (including the Regulatory Documentation and Regulatory Approvals and any information or data contained therein), any Exploitation of the Licensed Products in the Territory or the scientific, regulatory or business affairs or other activities of either Party. Notwithstanding the foregoing, Confidential Information shall not include any information that:

9.1.1    is or hereafter becomes part of the public domain through no wrongful act, fault or negligence on the part of the Receiving Party;

9.1.2    can be demonstrated by documentation or other competent proof to have been in the Receiving Party’s possession prior to disclosure by the Disclosing Party without any obligation of confidentiality with respect to such information;

9.1.3    is subsequently received by the Receiving Party, without confidentiality restrictions, from a Third Party who is not bound by any obligation of confidentiality with respect to such information; or

9.1.4    can be demonstrated by documentation or other competent evidence to have been independently developed by or for the Receiving Party without use of or reference to the Disclosing Party’s Confidential Information.

Specific aspects or details of Confidential Information shall not be deemed to be within the public domain or in the possession of the Receiving Party merely because the Confidential Information is embraced by more general information in the public domain or in the possession of the Receiving Party. Further, any combination of Confidential Information shall not be considered in the public domain or in the possession of the Receiving Party merely because individual elements of such Confidential Information are in the public domain or in the possession of the Receiving Party unless the combination and its principles are in the public domain or in the possession of the Receiving Party.

9.2    Permitted Disclosures. Each Receiving Party may disclose Confidential Information disclosed to it by the Disclosing Party to the extent that such disclosure by the Receiving Party is:

9.2.1    made in response to a valid order of a court of competent jurisdiction or other supra-national, federal, national, regional, state, provincial and local governmental or regulatory body of competent jurisdiction or, if in the reasonable opinion of the Receiving Party’s legal counsel, such disclosure is otherwise required by Applicable Law or the requirements of a national securities exchange or other similar regulatory body; provided that the Receiving Party shall first have given notice, to the extent legally permitted, to the Disclosing Party and given the Disclosing Party a reasonable opportunity to quash such order and to obtain a protective order requiring that the Confidential Information and documents that are the subject of such order be held in confidence by such court or agency or, if disclosed, be used only for the purposes for which the order was issued; and provided further that if a disclosure order is not quashed or a protective order is not obtained, the Confidential Information disclosed in response to such court or governmental order shall be limited to the information that is legally required to be disclosed in response to such court or governmental order;

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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9.2.2    made by the Receiving Party to a Regulatory Authority as required in connection with any filing, application or request for Regulatory Approval; provided that reasonable measures shall be taken to obtain confidential treatment of such information;

9.2.3    made by the Receiving Party as necessary to file or prosecute Patent applications pursuant to Section 7.1.1 or Section 7.2.1, as applicable, prosecute or defend litigation or otherwise establish rights or enforce obligations under this Agreement; provided that reasonable measures shall be taken to obtain confidential treatment of such information; or

9.2.4    made by the Receiving Party to advisors, actual or prospective acquirers, merger candidates, actual or prospective investors or funding sources or actual or prospective Sublicensees (with respect to X4 as the Receiving Party), or, with respect to Genzyme as the Receiving Party, investors in connection with a Monetization (and to its and their respective Affiliates, representatives and financing sources); provided that (a) each such Third Party signs an agreement that contains obligations that are substantially similar to the Receiving Party’s obligations hereunder except that the obligations under such agreement may terminate five years after disclosure of the relevant information, and (b) each such Third Party to whom information is disclosed shall (i) be subject to reasonable obligations of confidentiality, (ii) be informed of the confidential nature of the Confidential Information so disclosed, and (iii) agree to hold such Confidential Information subject to the terms thereof.

9.3    Use of Names. Except as expressly provided in this Agreement, neither Party shall mention or otherwise use the name, insignia, symbol, Trademark of the other Party (or any abbreviation or adaptation thereof) in any publication, press release, marketing and promotional material or other form of publicity without the prior written approval of such other Party in each instance, such approval not be unreasonably conditioned, withheld or delayed. The restrictions imposed by this Section 9.3 shall not prohibit either Party from making any disclosure (a) identifying the other Party as a counterparty to this Agreement to its investors, (b) that is required by Applicable Law or the requirements of a national securities exchange or another similar regulatory body or (c) with respect to which written consent has previously been obtained. Further, the restrictions imposed on each Party under this Section 9.3 are not intended, and shall not be construed, to prohibit a Party from identifying the other Party in its internal business communications, provided that any Confidential Information in such communications remains subject to this Article 9.

9.4    Press Releases. Neither Party shall issue any press release or other similar public communication relating to this Agreement, its subject matter or the transactions covered by it, or the activities of the Parties under or in connection with this Agreement, without the prior written approval of the other Party, except (a) for communications required by Applicable Law as reasonably advised by the issuing Party’s counsel (provided that the other Party is given a reasonable opportunity to review and comment on any such press release or public communication in advance thereof to the extent legally permitted and the issuing Party shall act in good faith to incorporate any reasonable comments provided by the other Party on such press release or public communication), (b) for information that has been previously disclosed publicly or (c) as otherwise set forth in this Agreement. The Parties agree that X4 may issue a press release to announce the execution of this Agreement, a draft of which shall be provided to and approved by Genzyme.

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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9.5    Publications. Each Party acknowledges that the other Party’s personnel may desire to publish in scientific journals or present at scientific conferences scientific, pre-clinical or clinical data derived from research and development related to the Licensed Compounds and Licensed Products conducted in accordance with the terms of this Agreement. Accordingly, no such publication will be submitted and no such presentation shall be made unless a written copy of such proposed publication or presentation is submitted by the Party wishing to publish (“Publishing Party”) to the other Party (“Consulted Party”) [***] before submission for publication or presentation. The Consulted Party shall notify the Publishing Party in writing [***] whether such draft contains (a) information of the Consulted Party which it considers to be Confidential Information, (b) information that if published would have an adverse effect on a patent application covering the subject matter of this Agreement, or (c) information that such Consulted Party reasonably believes would be likely to have a material adverse impact on the Development, Manufacture or Commercialization of a Licensed Product, or the Exploitation of rights retained under Section 2.2.2. In the case of item (a) above, the Publishing Party may not publish Confidential Information of the Consulted Party without its written consent. In the case of item (b) above, the Consulted Party may request a delay and the Publishing Party shall delay such publication or presentation, [***], to permit the timely preparation and filing of a patent application or an application for a certificate of invention covering the information at issue. In the case of item (c) above, if the Publishing Party disagrees with the Consulted Party’s assessment of the impact of the publication or presentation, then the issue shall be resolved pursuant to Section 13.5. X4 and Genzyme will each comply with standard academic practice regarding authorship of scientific publications and recognition of contribution of other parties in any publication.

9.6    Destruction of Confidential Information. Within [***] after the earlier of (a) the expiration of the Term, (b) the termination of this Agreement, or (c) the written request of the Disclosing Party, the Receiving Party shall promptly destroy all documentary, electronic or other tangible embodiments of the Disclosing Party’s Confidential Information to which the Receiving Party does not retain rights hereunder and any and all copies thereof, and destroy those portions of any documents that incorporate or are derived from the Disclosing Party’s Confidential Information to which the Receiving Party does not retain rights hereunder, and provide a written certification of such destruction, except that the Receiving Party may retain one copy thereof, to the extent that the Receiving Party requires such Confidential Information for the purpose of performing any obligations or exercising any rights under this Agreement that may survive such expiration or termination, or for archival purposes. Notwithstanding the foregoing, the Receiving Party also shall be permitted to retain such additional copies of or any computer records or files containing the Disclosing Party’s Confidential Information that have been created solely by the Receiving Party’s automatic archiving and back-up procedures, to the extent created and retained in a manner consistent with the Receiving Party’s standard archiving and back-up procedures, but not for any other use or purpose.

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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ARTICLE 10

REPRESENTATIONS AND WARRANTIES; COVENANTS

10.1    Mutual Representations and Warranties. Each Party hereby represents and warrants to the other Party as of the Effective Date as follows:

10.1.1    Corporate Authority. Such Party (a) has the power and authority and the legal right to enter into this Agreement and perform its obligations hereunder and (b) has taken all necessary action on its part required to authorize the execution and delivery of this Agreement and the performance of its obligations hereunder. This Agreement has been duly executed and delivered by such Party and constitutes a legal, valid and binding obligation of such Party and is enforceable against it in accordance with its terms subject to the effects of bankruptcy, insolvency or other laws of general application affecting the enforcement of creditor rights and judicial principles affecting the availability of specific performance and general principles of equity, whether enforceability is considered in a proceeding at law or equity.

10.1.2    Consents and Approvals. All necessary consents, approvals and authorizations of all Regulatory Authorities and other Persons required to be obtained by such Party in connection with the execution and delivery of this Agreement have been obtained.

10.1.3    Conflicts. The execution and delivery of this Agreement and the performance of such Party’s obligations hereunder (a) do not conflict with or violate any requirement of Applicable Law or any provision of the articles of incorporation or bylaws of such Party in any material way and (b) do not conflict with, violate or breach or constitute a default or require any consent under, any contractual obligation or court or administrative order by which such Party is bound.

10.2    Representations, Warranties and Covenants of X4. Neither X4 nor any of its Affiliates has been debarred or is subject to debarment and neither X4 nor any of its Affiliates will use in any capacity, in connection with the activities to be performed under this Agreement, any Person who, to X4’s knowledge after due inquiry, has been debarred pursuant to Section 306 of the FFDCA or who is the subject of a conviction described in such section. X4 shall inform Genzyme in writing immediately if it or any Person who is performing activities hereunder is debarred or is the subject of a conviction described in Section 306 or if any action, suit, claim, investigation or legal or administrative proceeding is pending or, to the best of X4’s knowledge, is threatened, relating to the debarment or conviction of X4 or any Person performing activities hereunder.

10.3    Representations and Warranties of Genzyme. Genzyme hereby represents and warrants to X4 that as of the Effective Date:

10.3.1    Genzyme or its Affiliate owns all right, title and interest in and to the Licensed Patents listed on Schedule 1.58, and, to Genzyme’s Knowledge, the Licensed Patents listed in Exhibit 1.58 are the only Patents Controlled by Genzyme that claim (specifically or generically) the composition, method of manufacture or method of use of any Licensed Compound;

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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10.3.2    Genzyme has not granted to any Affiliate or Third Party any rights in the Licensed Know-How or Licensed Patents that are inconsistent with the rights granted to X4 under this Agreement;

10.3.3    No Third Party has made or threatened in writing a claim of infringement or misappropriation with respect to the Licensed Compounds;

10.3.4    To Genzyme’s Knowledge, there is no infringement or misappropriation of any Licensed Patent or any Licensed Know-How by any Third Party;

10.3.5    All Licensed Patent Rights listed on Schedule 1.58 are existing and, to Genzyme’s Knowledge, no issued Patents which are part of Licensed Patent Rights listed on Schedule 1.58 are invalid or unenforceable;

10.3.6    There are no claims, judgment or settlements against Genzyme pending, or to Genzyme’s Knowledge, threatened, that invalidate or seek to invalidate the Licensed Patents;

10.3.7    Genzyme is not a party to any agreement with the U.S. Federal government or an agency thereof pursuant to which the U.S. Federal government or such agency provided funding for the development of a Licensed Compound;

For purposes of this Section 10.3, “Genzyme’s Knowledge” means the actual knowledge (without enquiry or investigation) of Genzyme.

10.4    DISCLAIMER OF WARRANTY. EXCEPT FOR THE EXPRESS WARRANTIES SET FORTH IN SECTION 10.1 AND SECTION 10.2, NEITHER PARTY MAKES ANY REPRESENTATIONS OR GRANTS ANY WARRANTY, EXPRESS OR IMPLIED, EITHER IN FACT OR BY OPERATION OF LAW, BY STATUTE OR OTHERWISE, AND EACH PARTY SPECIFICALLY DISCLAIMS ANY OTHER WARRANTIES, WHETHER WRITTEN OR ORAL, OR EXPRESS OR IMPLIED, INCLUDING ANY WARRANTY OF QUALITY, MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE OR PURPOSE OR ANY WARRANTY AS TO THE VALIDITY OF ANY PATENTS OR THE NON-INFRINGEMENT OF ANY INTELLECTUAL PROPERTY RIGHTS OF THIRD PARTIES.

10.5    ADDITIONAL WAIVER. X4 AGREES THAT: (A) EXCEPT AS SPECIFICALLY PROVIDED IN SECTION 10.3, THE LICENSED PATENTS AND LICENSED KNOW-HOW ARE LICENSED “AS IS”, “WITH ALL FAULTS” AND “WITH ALL DEFECTS”, AND X4 EXPRESSLY WAIVES ALL RIGHTS TO MAKE ANY CLAIM WHATSOEVER AGAINST GENZYME FOR MISREPRESENTATION OR FOR BREACH OF PROMISE, GUARANTEE OR WARRANTY OF ANY KIND RELATING TO THE LICENSED PATENTS OR LICENSED KNOW-HOW; (B) GENZYME WILL HAVE NO LIABILITY TO X4 FOR ANY ACT OR OMISSION PRIOR TO THE EFFECTIVE DATE IN THE PREPARATION, FILING, PROSECUTION, MAINTENANCE, ENFORCEMENT, DEFENCE OR OTHER HANDLING OF THE LICENSED PATENTS; AND (C) X4 IS SOLELY RESPONSIBLE FOR DETERMINING WHETHER THE LICENSED PATENTS AND LICENSED KNOW-HOW HAVE APPLICABILITY OR UTILITY IN X4’S CONTEMPLATED EXPLOITATION OF THE LICENSED PRODUCT, AND X4 ASSUMES ALL RISK AND LIABILITY IN CONNECTION WITH SUCH DETERMINATION.

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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ARTICLE 11

INDEMNITY

11.1    Indemnification of Genzyme. X4 shall indemnify Genzyme, its Affiliates and its and their respective directors, officers, employees and agents (collectively, “Genzyme Indemnitees”), and defend and save each of them harmless, from and against any and all losses, damages, liabilities, costs and expenses (including reasonable attorneys’ fees and expenses) (collectively, “Losses”) in connection with any and all suits, investigations, claims or demands of Third Parties (collectively, “Third Party Claims”) arising from or occurring as a result of: (a) the breach by X4 of any representation, warranty, covenant, obligation or agreement made or undertaken by X4 under this Agreement, (b) the gross negligence or willful misconduct on the part of any X4 Indemnitee or (c) the Exploitation of any Licensed Compounds or Licensed Products in the Field by or on behalf of X4, its Sublicensees or any of its or their respective Affiliates; provided that, with respect to any Third Party Claim for which X4 has an obligation to any Genzyme Indemnitee pursuant to this Section 11.1 and Genzyme has an obligation to any X4 Indemnitee pursuant to Section 11.2, each Party shall indemnify each of the Genzyme Indemnitees or the X4 Indemnitees, as applicable, for its Losses to the extent of its responsibility, relative to the other Party. The foregoing indemnification obligation shall not apply to the extent that the Genzyme Indemnitees fail to comply with the indemnification procedures set forth in Sections 11.3 and 11.4 and X4’s defense of the relevant Claims is prejudiced by such failure.

11.2    Indemnification of X4. Genzyme shall indemnify X4, its Affiliates and its and their respective directors, officers, employees and agents (collectively, “X4 Indemnitees”), and defend and save each of them harmless, from and against any and all Losses in connection with any and all Third Party Claims arising from or occurring as a result of: (a) the breach by Genzyme of any representation, warranty, covenant, obligation or agreement made or undertaken by Genzyme under this Agreement or (b) the gross negligence or willful misconduct on the part of any Genzyme Indemnitee; provided that, with respect to any Third Party Claim for which Genzyme has an obligation to any X4 Indemnitee pursuant to this Section 11.2 and X4 has an obligation to any Genzyme Indemnitee pursuant to Section 11.1, each Party shall indemnify each of the Genzyme Indemnitees or the X4 Indemnitees, as applicable, for its Losses to the extent of its responsibility, relative to the other Party. The foregoing indemnification obligation shall not apply to the extent that the X4 Indemnitees fail to comply with the indemnification procedures set forth in Sections 11.3 and 11.4 and Genzyme’s defense of the relevant Claims is prejudiced by such failure.

11.3    Notice of Claim. All indemnification claims in respect of a Genzyme Indemnitee or a X4 Indemnitee shall be made solely by Genzyme or X4, as applicable (each of Genzyme or X4 in such capacity, the “Indemnified Party”). The Indemnified Party shall give the Indemnifying Party prompt written notice (an “Indemnification Claim Notice”) of any Losses or discovery of fact upon which such Indemnified Party intends to base a request

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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for indemnification under Section 11.1 or Section 11.2, but in no event shall the Indemnifying Party be liable for any Losses that result from any delay in providing such notice. Each Indemnification Claim Notice must contain a description of the claim and the nature and amount of such Loss (to the extent that the nature and amount of such Loss is known at such time). The Indemnified Party shall furnish promptly to the Indemnifying Party copies of all papers and official documents received in respect of any Losses and Third Party Claims.

11.4    Control of Defense.

11.4.1    Control of Defense. At its option, the Indemnifying Party may assume the defense of any Third Party Claim by giving written notice to the Indemnified Party [***]. The assumption of the defense of a Third Party Claim by the Indemnifying Party shall not be construed as an acknowledgment that the Indemnifying Party is liable to indemnify any Genzyme Indemnitee or X4 Indemnitee, as applicable, in respect of the Third Party Claim, nor shall it constitute a waiver by the Indemnifying Party of any defenses it may assert against a Genzyme Indemnitee’s or a X4 Indemnitee’s, as applicable, claim for indemnification. Upon assuming the defense of a Third Party Claim, the Indemnifying Party may appoint as lead counsel in the defense of the Third Party Claim any legal counsel selected by the Indemnifying Party. In the event the Indemnifying Party assumes the defense of a Third Party Claim, the Indemnified Party shall immediately deliver to the Indemnifying Party all original notices and documents (including court papers) received by any Genzyme Indemnitee or X4 Indemnitee, as applicable, in connection with the Third Party Claim. If the Indemnifying Party assumes the defense of a Third Party Claim, except as provided in Section 11.4.2, the Indemnifying Party shall not be liable to the Indemnified Party for any legal expenses subsequently incurred by such Indemnified Party or any Genzyme Indemnitee or X4 Indemnitee, as applicable, in connection with the analysis, defense or settlement of such Third Party Claim. In the event that it is ultimately determined that the Indemnifying Party is not obligated to indemnify, defend or hold harmless a Genzyme Indemnitee or X4 Indemnitee, as applicable, from and against a Third Party Claim, the Indemnified Party shall reimburse the Indemnifying Party for any and all costs and expenses (including attorneys’ fees and costs of suit) incurred by the Indemnifying Party in its defense of such Third Party Claim.

11.4.2    Right to Participate in Defense. Without limiting Section 11.4.1, any Indemnified Party shall be entitled to participate in, but not control, the defense of a Third Party Claim and to employ counsel of its choice for such purpose; provided that such employment shall be at the Indemnified Party’s own expense unless (a) the employment thereof has been specifically authorized by the Indemnifying Party in writing, (b) the Indemnifying Party has failed to assume the defense and employ counsel in accordance with Section 11.4.1 (in which case the Indemnified Party shall control the defense) or (c) the interests of the Indemnified Party and any Genzyme Indemnitee or X4 Indemnitee, as applicable, on the one hand, and the Indemnifying Party, on the other hand, with respect to such Third Party Claim are sufficiently adverse to prohibit the representation by the same counsel of all such Persons under Applicable Law, ethical rules or equitable principles.

11.4.3    Settlement. With respect to any Third Party Claims relating solely to the payment of money damages in connection with a Third Party Claim that shall not result in any

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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Genzyme Indemnitee or X4 Indemnitee, as applicable, becoming subject to injunctive or other relief or otherwise adversely affecting the business, rights, or interests of any Genzyme Indemnitee or X4 Indemnitee, as applicable, in any manner and as to which the Indemnifying Party shall have acknowledged in writing the obligation to indemnify such Genzyme Indemnitee or X4 Indemnitee, as applicable, hereunder, the Indemnifying Party shall have the sole right to consent to the entry of any judgment, enter into any settlement or otherwise dispose of such Third Party Claim, on such terms as the Indemnifying Party, in its sole discretion, shall deem appropriate. With respect to all other Third Party Claims, where the Indemnifying Party has assumed the defense of the Third Party Claim in accordance with Section 11.4.1, the Indemnifying Party shall have authority to consent to the entry of any judgment, enter into any settlement or otherwise dispose of such Third Party Claim, provided that it obtains the prior written consent of the Indemnified Party (such consent not to be unreasonably conditioned, withheld or delayed). The Indemnifying Party shall not be liable for any settlement or other disposition of a Third Party Claim by a Genzyme Indemnitee or a X4 Indemnitee that is reached without the prior written consent of the Indemnifying Party. So long as the Indemnifying Party is actively defending or prosecuting any Third Party Claim, the Indemnified Party shall not, and the Indemnified Party shall ensure that each Genzyme Indemnitee or X4 Indemnitee, as applicable, does not, admit any liability with respect to or settle, compromise or discharge, such Third Party Claim without the prior written consent of the Indemnifying Party, such consent not to be unreasonably conditioned, withheld or delayed. If the Indemnifying Party does not assume and conduct the defense of a Third Party Claim [***], the Indemnified Party may consent to the entry of any judgment or enter into any settlement with respect to such Third Party Claim in any manner the Indemnified Party may deem reasonably appropriate. For clarity, the assumption of the defense of any Third Party Claim by the Indemnified Party in accordance with the preceding sentence shall in no event relieve the Indemnifying Party from its obligations to indemnify and hold harmless the Indemnified Party from all Losses arising from such Third Party Claim.

11.4.4    Cooperation. Regardless of whether the Indemnifying Party chooses to defend or prosecute any Third Party Claim, the Indemnified Party shall, and shall cause each Genzyme Indemnitee or X4 Indemnitee, as applicable, to, cooperate in the defense or prosecution thereof and shall furnish such records, information and testimony, provide such witnesses and attend such conferences, discovery proceedings, hearings, trials and appeals as may be reasonably requested in connection therewith. Such cooperation shall include access during normal business hours afforded to the Indemnifying Party to, and reasonable retention by the Indemnified Party and any Genzyme Indemnitee or X4 Indemnitee, as applicable, of, records and information that are reasonably relevant to such Third Party Claim, and making all Genzyme Indemnitees or X4 Indemnitees, as applicable, and other employees and agents available on a mutually convenient basis to provide additional information and explanation of any material provided hereunder; provided that neither Party shall be required to disclose legally privileged information unless and until procedures reasonably acceptable to such Party are in place to protect such privilege, and the Indemnifying Party shall reimburse the Indemnified Party for all its reasonable costs and expenses in connection therewith.

11.4.5    Expenses. Except as provided above, the costs and expenses, including fees and disbursements of counsel, incurred by the Indemnified Party in connection with any Third Party Claim shall be reimbursed on a Calendar Quarter basis by the Indemnifying Party, without

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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prejudice to the Indemnifying Party’s right to contest any Genzyme Indemnitee’s or X4 Indemnitee’s, as applicable, right to indemnification and subject to refund in the event the Indemnifying Party is ultimately held not to be obligated to indemnify a Genzyme Indemnitee or X4 Indemnitee, as applicable.

11.5    Limitation on Damages and Liability. [***], NEITHER PARTY NOR ANY OF THEIR RESPECTIVE AFFILIATES SHALL BE LIABLE FOR SPECIAL, INDIRECT, INCIDENTAL OR CONSEQUENTIAL DAMAGES, OR FOR LOST PROFITS, WHETHER IN CONTRACT, WARRANTY, NEGLIGENCE, TORT, STRICT LIABILITY OR OTHERWISE, ARISING OUT OF (a) THE DEVELOPMENT, MANUFACTURE, USE OR SALE OF THE LICENSED PRODUCTS UNDER THIS AGREEMENT, (b) THE USE OF OR REFERENCE TO THE LICENSED PATENTS, LICENSED KNOW-HOW OR REGULATORY DOCUMENTATION OR (c) ANY BREACH OF OR FAILURE TO PERFORM ANY OF THE PROVISIONS OF THIS AGREEMENT.

11.6    Insurance. X4 shall, and shall cause its Sublicensees and its and their respective Affiliates to maintain (a) no later than thirty days prior to the anticipated date of First Commercial Sale of a Licensed Product, (i) commercial general liability insurance covering bodily injury and property damage of not less than [***] per occurrence and in the aggregate, and (ii) clinical trials liability insurance coverage with minimum indemnity limits of [***] per occurrence and in the aggregate, and (b) following the First Commercial Sale of a Licensed Product, and thereafter during any period in which X4 has indemnification obligations to Genzyme, (i) commercial general liability insurance covering bodily injury and property damage of not less than [***] per occurrence and in the aggregate, and (ii) products liability/completed operations and clinical trials liability insurance coverage with minimum indemnity limits of [***] per occurrence and in the aggregate. Such policies shall be provided by insurance carrier(s) reasonably acceptable to Genzyme. [***]. If such policies are written on a claims made basis, they shall remain in effect for a minimum period of [***] and shall not be cancelled or subject to a reduction of coverage without the prior written authorization of Genzyme. Upon Genzyme’s written request, X4 shall provide Genzyme with certificate(s) of insurance or certified copies of X4’s insurance policies to evidence the purchase and/or maintenance of such policies. Maintenance of such insurance coverage shall not relieve X4 of any responsibility under this Agreement for damages in excess of insurance limits or otherwise.

ARTICLE 12

TERM AND TERMINATION

12.1    Termination upon Failure to Close the X4 First Financing. [***]. In the event that X4 does not consummate [***], then the Financing Exclusivity Period shall automatically be extended by [***]. In the event that X4 does not [***], as so extended, and the Parties have not otherwise agreed in writing to further extend such period, this Agreement shall immediately terminate and Genzyme shall have no further obligations to X4 with respect to the Licensed Patent and Licensed Know-How and shall be free to negotiate and enter into any agreement with a Third Party concerning the Licensed Patents or the Licensed Know How.

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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12.2    Term. This Agreement shall commence on the Effective Date and shall, unless earlier terminated in accordance with this ARTICLE 12, continue (a) with respect to each Licensed Product in each country in the Territory, until the expiration of the Royalty Term for such Licensed Product in such country and (b) with respect to this Agreement in its entirety, until the expiration of the last-to-expire Royalty Term for any Licensed Product in the Territory (such period, the “Term”).

12.3    Termination of this Agreement for Material Breach. In the event that either Party materially breaches this Agreement (such Party, the “Breaching Party”), in addition to any other right and remedy the other Party (the “Complaining Party”) may have, the Complaining Party may terminate this Agreement, in its entirety upon ninety (90) days’ prior written notice (the “Termination Notice Period”) to the Breaching Party, specifying the material breach and its claim of right to terminate, provided that the termination shall not become effective at the end of the Termination Notice Period if the Breaching Party cures the material breach complained of during the Termination Notice Period The Breaching Party may dispute any alleged breach by written notice to the Complaining Party within such ninety-(90) day period, in which case the Complaining Party shall not have the right to terminate this Agreement pursuant to this Section 12.3 unless and until it has been mutually agreed pursuant to Section 13.5 or determined in accordance with Section 13.5 below that this Agreement was materially breached by the Breaching Party, and the Breaching Party fails to comply with its obligations hereunder within ninety (90) days after such mutual agreement or determination, as applicable. Notwithstanding the foregoing, it is understood and agreed that termination of this Agreement pursuant to this Section 12.3 shall in no way limit either Party’s right to seek all remedies available by law and in equity.

12.4    Unilateral Termination Rights.

12.4.1    In the event that X4 or any of its Affiliates anywhere in the Territory, institutes, prosecutes or otherwise participates in (or in any way aids any Third Party in instituting, prosecuting or participating in), at law or in equity or before any administrative or regulatory body, including the U.S. Patent and Trademark Office or its foreign counterparts, any claim, demand, action or cause of action for declaratory relief, damages or any other remedy or for an enjoinment, injunction or any other equitable remedy, including any interference, reexamination, post grant review, opposition or any similar proceeding, alleging that any claim in a Licensed Patent is invalid, unenforceable or otherwise not patentable (a “Patent Challenge”) (except as required under a court order or subpoena), Genzyme may terminate this Agreement immediately upon written notice to X4. In the event that a Sublicensee of X4 or an Affiliate thereof anywhere in the Territory institutes, prosecutes or otherwise participates in (or in any way aids any Third Party in instituting, prosecuting or participating in) a Patent Challenge (except as required under a court order or subpoena), then Genzyme may send a written demand to X4 to terminate such sublicense in the event such Sublicensee fails to withdraw such Patent Challenge or such Patent Challenge is otherwise not dismissed [***]. If such Sublicensee fails to withdraw such Patent Challenge or such Patent Challenge is not dismissed [***], and thereafter, X4 shall terminate such Sublicense [***]. Notwithstanding the foregoing, Genzyme shall not have any termination rights pursuant to

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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this Section 12.4.1 on account of any Patent Challenge that is either (i) a legal or administrative challenge asserted as a counterclaim in an action initiated by or under the authority of Genzyme against X4, its Sublicensees or their respective Affiliates, or (ii) a declaratory action proceeding brought against Genzyme with respect to the validity, patentability or enforceability of any Licensed Patent as a result of Genzyme threatening to bring any action against X4, its Sublicensees, or their respective Affiliates.

12.4.2    X4 may terminate this Agreement in its entirety immediately upon notice to Genzyme for a Material Safety Issue. “Material Safety Issue” shall mean the reasonable belief of X4 or any of its Affiliates’ or Sublicensees’ based upon additional information that becomes available or an analysis of the existing information at any time, that the medical risk/benefit profile of the Licensed Compound or a Licensed Product is so unfavorable that it would be incompatible with the welfare of patients to Develop or Commercialize such Licensed Compound or Licensed Product or to continue to Develop or Commercialize it. In the event of a dispute as to whether a Material Safety Issue exists, the Parties shall resolve the dispute in accordance with Section 13.5, unless the Data Safety Monitoring Board or any institutional Review Board or any Regulatory Authority has recommended to X4 or Genzyme, or their Sublicensees or Affiliates, to terminate an ongoing Clinical Study of the Licensed Compound or Licensed Product or has halted or placed any such ongoing Clinical Study on hold, or a Regulatory Authority has withdrawn or requested that X4 withdraw any applicable Regulatory Approval for a Licensed Product, all of which foregoing circumstances shall be deemed conclusive evidence of the existence of a Material Safety Issue giving rise to X4’s right to terminate under this Section 12.4.2.

12.5    Termination Upon Insolvency. Either Party may terminate this Agreement if, at any time, the other Party (a) files in any court or agency pursuant to any statute or regulation of any state, country or jurisdiction, a petition in bankruptcy or insolvency or for reorganization or for an arrangement or for the appointment of a receiver or trustee of such other Party or of its assets, (b) is declared insolvent or bankrupt by a court of competent jurisdiction, (c) is served with an involuntary petition against it, filed in any insolvency proceeding that is not dismissed within ninety (90) days after the filing thereof, (d) proposes or is placed in a process of complete liquidation, or (e) makes an assignment of substantially all of its assets for the benefit of its creditors.

12.6    Rights in Bankruptcy. All rights and licenses granted under or pursuant to this Agreement by X4 or Genzyme are, and shall otherwise be deemed to be, for purposes of Section 365(n) of the U.S. Bankruptcy Code, licenses of right to “intellectual property” as defined under Section 101 of the U.S. Bankruptcy Code. The Parties agree that the Parties, as licensees of such rights under this Agreement, shall retain and may fully exercise all of their rights and elections under the U.S. Bankruptcy Code.

12.7    Consequences of Termination.

12.7.1    In the event of a termination of this Agreement for any reason, any Sublicense agreement entered into by X4 as of the effective date of termination shall remain in full force and effect; provided, that, (a) the applicable Sublicensee is not then in breach of its Sublicense agreement with X4 and agrees to be bound to Genzyme as a direct licensee under the terms and conditions of the Sublicense agreement and (b) the Sublicensee promptly enters into appropriate agreements or amendments to the Sublicense agreement to substitute Genzyme for X4 as the licensor thereunder.

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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12.7.2    In the event of a termination of this Agreement for any reason other than as provided in Section 12.7.4, all rights and licenses granted by Genzyme hereunder shall immediately terminate; provided, that, if such termination occurs after the First Commercial Sale of a Licensed Product hereunder, X4 and its Sublicensees and Affiliates shall have the right to continue selling any or all Licensed Product remaining in their inventory for [***], provided that the sale of such remaining inventory will be subject to the royalty obligations set forth in Section 6.5.

12.7.3    Upon termination of this Agreement by Genzyme pursuant to Section 12.3 or 12.4.1, X4 shall promptly, to the extent requested by Genzyme:

(a)    where permitted by Applicable Law, assign to Genzyme all of its right, title and interest in and to, and transfer possession to Genzyme of, all Regulatory Documentation (including, for clarity, Regulatory Approvals) then in its name applicable to any Licensed Product in the Territory;

(b)    notify the applicable Regulatory Authorities and take any other action reasonably necessary to effect the transfer set forth in clause (a) above;

(c)    grant Genzyme [***], under all Regulatory Documentation (including any Regulatory Approvals) then owned or Controlled by X4 then in its name that are not assigned to Genzyme pursuant to clause (a) above that are necessary or useful for Genzyme or any of its Affiliates to Exploit any Licensed Compound or Licensed Product in the Field in the Territory and any improvement to any of the foregoing, as such Regulatory Documentation exists as of the effective date of such termination of this Agreement and X4 shall continue to maintain such Regulatory Documentation (including any Regulatory Approvals) unless and until Genzyme notifies X4 that such maintenance is no longer required;

(d)    to the extent requested in writing by Genzyme, grant Genzyme [***], under the X4 Know-How and the X4 Patents, to Exploit Licensed Products in the Field and, following any such termination, the provisions of ARTICLE 7 that apply to Licensed Patents shall survive with respect to such X4 Patents with Genzyme having, with respect to such X4 Patents, the rights and obligations that X4 has with respect to the Licensed Patents; provided, that, the survival of the licenses granted to Genzyme pursuant to this Section 12.7.3(d) shall be subject to [***]. For purposes of this Section 12.7.3(d), the term “X4 Licensed Product” shall mean any Licensed Product that is covered by a Valid Claim of any X4 Patents and for uses or incorporates any X4 Know-How and “Applicable Post-Termination Percentage” means, with respect to each X4 Licensed Product described in this Section 12.7.3(d), (1) if the effective date of termination is [***] with respect to any such X4 Licensed Product in any country in the Territory, [***], (2) if the effective date of termination is [***] with respect to any such X4 Licensed Product in any country in the Territory but [***] with respect to such X4 Licensed Product in any country in the Territory, [***], (3) if the effective date of termination is on or after [***] with respect to any such X4 Licensed Product in any country in the Territory but prior to [***] with respect to any such X4 Licensed Product in any country in the Territory, [***], and (z) if the effective date of termination is [***] with respect to any such X4 Licensed Product in any country in the Territory, [***].

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

43

(e)    unless expressly prohibited by any Regulatory Authority, transfer control to Genzyme of all Clinical Studies of each Licensed Product being conducted as of the effective date of termination and continue to conduct such Clinical Studies, at Genzyme’s cost and expense, [***] to enable such transfer to be completed without interruption of any such Clinical Study; provided, that, Genzyme shall not have any obligation to continue any Clinical Study unless required by Applicable Law and (ii) with respect to each Clinical Study for which such transfer is expressly prohibited by the applicable Regulatory Authority, X4 shall continue to conduct such Clinical Study [***] at Genzyme’s reasonable cost and expense.

(f)    assign (or cause its Affiliates to assign) to Genzyme all Licensed Product Agreements, unless, with respect to any such Licensed Product Agreement, such Licensed Product Agreement expressly prohibits such assignment or relates to products in addition to the Licensed Product, in which case X4 shall cooperate with Genzyme in all reasonable respects to secure the consent of the applicable Third Party to such assignment and if any such consent cannot be obtained with respect to a Licensed Product Agreement, X4 shall use Commercially Reasonable Efforts at Genzyme’s cost and expense to try to obtain for Genzyme substantially all of the practical benefit and burden under such Licensed Product Agreement, including by (i) pursuing appropriate and reasonable alternative arrangements (such as splitting Licensed Product Agreements non exclusively related to Licensed Products) on terms mutually agreeable to Genzyme and X4 and (ii) subject to the consent and control of Genzyme, pursuing the enforcement, at Genzyme’s cost and expense and for the account of Genzyme, of any and all rights of X4 against the other party thereto arising out of the breach or cancellation thereof by such other party or otherwise; [***];

(g)    provide Genzyme with copies of all reports and data generated or obtained by X4 or any of its Affiliates that relate to any Licensed Product that have not previously been provided to Genzyme;

(h)    where permitted by Applicable Laws, assign to Genzyme all right, title, and interest of X4 in each Product Trademark; and

(i)    sell to Genzyme some or all of the inventory of Licensed Compound and/or Licensed Product in possession of X4 and Affiliates as of the termination date, at a price equal to [***].

Except in the event of termination of this Agreement by Genzyme pursuant to Section 12.3, Genzyme shall reimburse X4 for all reasonable, documented out-of-pocket expenses incurred by X4 in performing its obligations under Section 12.7.3(a) to (h).

12.7.4    Upon termination by X4 pursuant to Section 12.3 or 12.5, then: (a) the licenses granted by Genzyme to X4 pursuant to Section 2.1 hereof shall survive on a country-by-country and Licensed Product-by-Licensed Product basis until the expiration of the Royalty Term

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

44

for each such Licensed Product in each such country, subject to [***]; and (b) each Party shall promptly return or destroy all Confidential Information of the other Party; provided, further that, each Party may retain, subject to ARTICLE 7 hereof, (i) one (1) copy of the Confidential Information of the other Party in its archives for the purpose of establishing the contents thereof and ensuring compliance with its obligations hereunder and (ii) any Confidential Information of the other Party contained in its laboratory notebooks or databases; and X4 may retain and use Genzyme’s Confidential Information solely in connection with the exercise of its rights set forth in clause (a) of this Section 12.7.4.

12.7.5    Without limiting Genzyme’s rights under other provisions of this ARTICLE 12, in the event of any termination by Genzyme pursuant to Section 12.3 or by X4 pursuant to 12.4.2, X4 shall, at the request and expense of Genzyme, use Commercially Reasonable Efforts to provide Genzyme with such assistance, [***], as is reasonably necessary to effectuate a smooth and orderly transition of any Development, Manufacture and Commercialization activities to Genzyme or its designee so as to minimize any disruption of such activities. Further, upon Genzyme’s request and expense, in the event of any termination by Genzyme pursuant to Section 12.3 or by X4 pursuant to 12.4.2 after the First Commercial Sale of a Licensed Product hereunder, X4 shall provide such technical assistance, [***], as may reasonably be requested to transfer all Manufacturing technology that is or had been used by or on behalf of X4 and its Affiliates in connection with the Manufacture of any Licensed Compound or Licensed Product.

12.8    Accrued Rights; Surviving Obligations.

12.8.1    Accrued Rights. Termination or expiration of this Agreement for any reason shall be without prejudice to any rights that shall have accrued to the benefit of a Party prior to such termination or expiration. Such termination or expiration shall not relieve a Party from obligations that are expressly indicated to survive the termination or expiration of this Agreement.

12.8.2    Survival. Without limiting the foregoing, Article 1, Section 2.6, Section 3.4 (last sentence), Article 6 (with respect to any payment accrued but not paid prior to termination or expiration), Section 6.4.3 (with respect to deferred payments under a Transaction), Section 6.10 (for the length of time specified therein), Section 7.1, Sections 7.3 through 7.5 (with respect to any action or proceeding initiated prior to termination or expiration), Section 7.7 (with respect to any action or proceeding initiated prior to termination or expiration), Article 8, Article 9 (for the length of time specified in Section 9.1), Sections 10.4 and 10.5, Article 11, Sections 12.6 through 12.8 and Article 13 shall survive the termination or expiration of this Agreement for any reason. In addition, upon the expiration, but not an earlier termination, of this Agreement, Section 2.4 shall also survive.

ARTICLE 13

MISCELLANEOUS

13.1    Force Majeure. Neither Party shall be held liable or responsible to the other Party or be deemed to have defaulted under or breached this Agreement for failure or delay in fulfilling or performing any term of this Agreement (other than an obligation to make payments) when such failure or delay is caused by or results from events beyond the

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

45

reasonable control of the non-performing Party, including fires, floods, earthquakes, embargoes, shortages, epidemics, quarantines, war, acts of war (whether war be declared or not), terrorist acts, insurrections, riots, civil commotion, strikes, lockouts or other labor disturbances (whether involving the workforce of the non-performing Party or of any other Person), acts of God or acts, omissions or delays in acting by any governmental authority (each, a “Force Majeure Event”). The non-performing Party shall notify the other Party of a Force Majeure Event [***] by giving written notice to the other Party stating the nature of such Force Majeure Event, its anticipated duration, and any action being taken to avoid or minimize its effect. The suspension of performance shall be of no greater scope and no longer duration than is necessary and the non-performing Party shall use commercially reasonable efforts to remedy its inability to perform. In the event that such suspension of performance [***] and in the absence of such Force Majeure Event such suspension of performance would be a material breach of this Agreement, such other Party shall have the right to terminate this Agreement pursuant to Section 12.3.

13.2    Export Control. This Agreement is made subject to any restrictions concerning the export of products or technical information from the United States or other countries that may be imposed on or related to the Parties from time to time. Each Party agrees that it will not export, directly or indirectly, any technical information acquired from the other Party under this Agreement or any products using such technical information to a location or in a manner that at the time of export requires an export license or other governmental approval, without first obtaining the written consent to do so from the appropriate agency or other governmental entity in accordance with Applicable Law.

13.3    Assignment. Neither Party shall sell, transfer, assign, delegate, pledge or otherwise dispose of, whether voluntarily, involuntarily, by operation of law or otherwise, this Agreement or any of its rights or duties hereunder without the prior written consent of the other Party; provided that (a) Genzyme may, without such consent, assign this Agreement and its rights and obligations hereunder to an Affiliate, to the purchaser of the Licensed Patents or Licensed Know-How or to its successor entity or acquirer in the event of a merger, consolidation or change in control of Genzyme and (b) X4 may without such consent, [***], assign this Agreement and its rights and obligations hereunder in connection with a Change of Control; provided, further, that in either case ((a) or (b)), the assignee or transferee shall assume all obligations of its assignor or transferor under this Agreement and such assignor or transferor shall remain responsible to the other Party for the performance by such assignee or transferee of the rights and obligations of the assigning Party hereunder. Any attempted assignment or delegation in violation of the preceding sentence shall be void and of no effect. All validly assigned and delegated rights and obligations of the Parties hereunder shall be binding upon and inure to the benefit of and be enforceable by and against the successors and permitted assigns of Genzyme or X4, as the case may be. [***].

13.4    Severability. To the fullest extent permitted by Applicable Law, the Parties waive any provision of law that would render any provision in this Agreement invalid, illegal, or unenforceable in any respect. If any provision of this Agreement is held to be invalid, illegal, or unenforceable, in any respect, then such provision will be given no effect by the Parties and shall not form part of this Agreement. To the fullest extent permitted by

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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Applicable Law and if the rights or obligations of either Party will not be materially and adversely affected, all other provisions of this Agreement shall remain in full force and effect, and the Parties shall use their best efforts to negotiate a provision in replacement of the provision held invalid, illegal, or unenforceable that is consistent with Applicable Law and achieves, as nearly as possible, the original intention of the Parties.

13.5    Dispute Resolution. If a dispute arises between the Parties in connection with the interpretation, validity or performance of this Agreement or any document or instrument delivered in connection herewith, then either Party shall have the right to refer such dispute to the Executive Officers for attempted resolution by good faith negotiations during a period of [***]. Any final decision mutually agreed to by the Executive Officers shall be conclusive and binding on the Parties. If such Executive Officers are unable to resolve such dispute within such [***] period, either Party shall be free to institute litigation in accordance with Section 13.6 and seek such remedies as may be available. Notwithstanding anything in this Agreement to the contrary, either Party shall be entitled to institute litigation in accordance with Section 13.6 immediately if litigation is necessary to prevent irreparable harm to that Party.

13.6    Governing Law, Jurisdiction, Venue and Service.

13.6.1    Governing Law. This Agreement shall be governed by and construed in accordance with the laws of [***], excluding any conflicts or choice of law rule or principle that might otherwise refer construction or interpretation of this Agreement to the substantive law of another jurisdiction. The Parties agree to exclude the application to this Agreement of the United Nations Convention on Contracts for the International Sale of Goods.

13.6.2    Jurisdiction. Subject to Section 13.5 and Section 13.10, the Parties hereby irrevocably and unconditionally consent to the exclusive jurisdiction of the courts of [***] for any action, suit or proceeding (other than appeals therefrom) arising out of or relating to this Agreement, and agree not to commence any action, suit or proceeding (other than appeals therefrom) related thereto except in such courts. The Parties irrevocably and unconditionally waive their right to a jury trial.

13.6.3    Venue. The Parties further hereby irrevocably and unconditionally waive any objection to the laying of venue of any action, suit or proceeding (other than appeals therefrom) arising out of or relating to this Agreement in the courts of [***], and hereby further irrevocably and unconditionally waive and agree not to plead or claim in any such court that any such action, suit or proceeding brought in any such court has been brought in an inconvenient forum.

13.6.4    Service. Each Party further agrees that service of any process, summons, notice or document by registered mail to its address set forth in Section 13.7.2 shall be effective service of process for any action, suit or proceeding brought against it under this Agreement in any such court.

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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13.7    Notices.

13.7.1    Notice Requirements. Any notice, request, demand, waiver, consent, approval or other communication permitted or required under this Agreement shall be in writing, shall refer specifically to this Agreement and shall be deemed given only if delivered by hand or sent by facsimile transmission (with transmission confirmed) or by internationally recognized delivery service that maintains records of delivery, addressed to the Parties at their respective addresses specified in Section 13.7.2 or to such other address as the Party to whom notice is to be given may have provided to the other Party in accordance with this Section 13.7. Such notice shall be deemed to have been given as of the date delivered by hand or transmitted by facsimile (with transmission confirmed) or on the third Business Day (at the place of delivery) after deposit with an internationally recognized delivery service. Any notice delivered by facsimile shall be confirmed by a hard copy delivered as soon as practicable thereafter. This Section 13.7 is not intended to govern the day-to-day business communications necessary between the Parties in performing their obligations under the terms of this Agreement.

13.7.2    Address for Notice.

If to X4, to:

X4 Pharmaceuticals, LLC

281 School Street,

Belmont, MA 02478

Attention: CEO

Facsimile: +001 801 285 7570

E-Mail: pmragan@gmail.com

with a copy to (which shall not constitute notice):

Mintz Levin

One Financial Center

Boston, MA 02111

Attention: John Cheney

Facsimile: (617) 542-2241

E-Mail: jjcheney@mintz.com

If to Genzyme, to:

Genzyme Corp.

500 Kendall Street,

Cambridge, MA 02142

Attention: General Counsel

Facsimile: + 1 617 768 6938

E-Mail: tracey.quarles@genzyme.com

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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with a copy to (which shall not constitute notice):

Sanofi – Legal Operations

54 rue la Boétie

75008 Paris

France

Attention: Vice President, Legal Operations

Facsimile: +33 (0) 1 5377 4048

E-Mail: jose.ferrer@sanofi.com

13.8    Entire Agreement; Amendments. This Agreement, together with the Schedules attached hereto, sets forth and constitutes the entire agreement and understanding between the Parties with respect to the subject matter hereof and all prior agreements, understandings, promises and representations, whether written or oral, with respect thereto are superseded hereby, including that certain Material Transfer Agreement dated 11 February 2014 between X4 and Sanofi, an Affiliate of Genzyme. Each Party confirms that it is not relying on any representations or warranties of the other Party except as specifically set forth herein. No amendment, modification, release or discharge shall be binding upon the Parties unless in writing and duly executed by authorized representatives of both Parties.

13.9    English Language. This Agreement shall be written and executed in, and all other communications under or in connection with this Agreement shall be in, the English language. Any translation into any other language shall not be an official version thereof, and in the event of any conflict in interpretation between the English version and such translation, the English version shall control.

13.10    Equitable Relief. The Parties acknowledge and agree that the restrictions set forth in ARTICLE 9 are reasonable and necessary to protect the legitimate interests of the other Party and that such other Party would not have entered into this Agreement in the absence of such restrictions, and that any breach or threatened breach of any provision of ARTICLE 9 may result in irreparable injury to such other Party for which there will be no adequate remedy at law. In the event of a breach or threatened breach of any provision of ARTICLE 9, the non-breaching Party shall be entitled to seek to obtain from any court of competent jurisdiction injunctive relief, whether preliminary or permanent, specific performance and an equitable accounting of all earnings, profits and other benefits arising from such breach, which rights shall be cumulative and in addition to any other rights or remedies to which such non-breaching Party may be entitled in law or equity. Nothing in this Section 13.10 is intended, or should be construed, to limit either Party’s right to equitable relief or any other remedy for a breach of any other provision of this Agreement.

13.11    Waiver and Non-Exclusion of Remedies. Any term or condition of this Agreement may be waived at any time by the Party that is entitled to the benefit thereof, but no such waiver shall be effective unless set forth in a written instrument duly executed by or on behalf of the Party waiving such term or condition. The waiver by either Party of any right hereunder or of the failure to perform or of a breach by the other Party shall not be deemed a waiver of any other right hereunder or of any other breach or failure by the other Party whether of a similar nature or otherwise.

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

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13.12    No Benefit to Third Parties. The representations, warranties, covenants and agreements set forth in this Agreement are for the sole benefit of the Parties and their successors and permitted assigns, and they shall not be construed as conferring any rights on any other Persons.

13.13    Further Assurance. Each Party shall duly execute and deliver, or cause to be duly executed and delivered, such further instruments and do and cause to be done such further acts and things, including the filing of such assignments, agreements, documents and instruments, as may be necessary or as the other Party may reasonably request in connection with this Agreement or to carry out more effectively the provisions and purposes hereof, or to better assure and confirm unto such other Party its rights and remedies under this Agreement.

13.14    Relationship of the Parties. It is expressly agreed that Genzyme, on the one hand, and X4, on the other hand, shall be independent contractors and that the relationship between the two Parties shall not constitute a partnership, joint venture or agency. Neither Genzyme, on the one hand, nor X4, on the other hand, shall have the authority to make any statements, representations or commitments of any kind, or to take any action, which shall be binding on the other Party, without the prior written consent of the other Party to do so, such consent not to be unreasonably conditioned, withheld or delayed. All persons employed by a Party shall be employees of such Party and not of the other Party and all costs and obligations incurred by reason of any such employment shall be for the account and expense of such Party.

13.15    Counterparts. This Agreement may be executed in any number of counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument. This Agreement may be executed by facsimile or other electronic signatures and such signatures shall be deemed to bind each Party as if they were original signatures.

13.16    References. Unless otherwise specified, (a) references in this Agreement to any Article, Section or Schedule means references to such Article, Section or Schedule of this Agreement, (b) references in any section to any clause are references to such clause of such section and (c) references to any agreement, instrument or other document in this Agreement refer to such agreement, instrument or other document as originally executed or, if subsequently varied, replaced or supplemented from time to time, as so varied, replaced or supplemented and in effect at the relevant time of reference thereto.

13.17    Construction. Except where the context otherwise requires, wherever used, the singular shall include the plural, the plural the singular, the use of any gender shall be applicable to all genders and the word “or” is used in the inclusive sense (and/or). The captions of this Agreement are for convenience of reference only and in no way define, describe, extend or limit the scope or intent of this Agreement or the intent of any provision contained in this Agreement. The term “including” as used herein means including, without limiting the generality of any description preceding such term. The language of this Agreement shall be deemed to be the language mutually chosen by the Parties and no rule of strict construction shall be applied against either Party.

[SIGNATURE PAGE FOLLOWS.]

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

50

THIS AGREEMENT IS EXECUTED by the authorized representatives of the Parties as of the date first written above.

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

Schedule 1.57

Licensed Know-How

[Attached]

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

Schedule 1.58

Licensed Patents

[Attached]

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

Schedule 1.56

Licensed Compound

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

Schedule 3.1.2

Development Plan

[***]

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

Schedule 3.2.1

Regulatory Documents Assigned by Genzyme to X4

[***]

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

Exhibit 10.6

Execution Copy

AMENDMENT NO. 1 TO LICENSE AGREEMENT

This Amendment No. 1 to License Agreement (this “Amendment”) is dated as of October 23, 2014 (the “Amendment Effective Date”) by and between Genzyme Corp., a corporation having an address at 500 Kendall Street, Cambridge, MA 02142 (“Genzyme” or “Licensor”) and X4 Pharmaceuticals, INC., a Delaware corporation having an address at 281 School Street, Belmont, MA 02478, United States (“X4”). Each of Genzyme and X4 may be referred to herein as a “Party” and together as the “Parties”. Capitalized terms used but not otherwise defined herein shall have the meanings ascribed to such terms in the License Agreement by and between the Parties effective as of July 10, 2014 (the “Agreement”).

WHEREAS, the Parties hereto desire to amend the Agreement as set forth herein to, among other things, include the right of X4 to extend a certain milestone date and to reflect the conversion of X4 from a limited liability company to a corporation; and

WHEREAS, pursuant to Section 13.8 of the Agreement, the Agreement may be amended by a written instrument duly executed by authorized representatives of both Parties.

NOW, THEREFORE, in consideration of the mutual covenants contained herein, and for other good and valuable consideration, the receipt and adequacy of which are hereby acknowledged, the Parties hereto, intending to be legally bound, hereby agree as follows:

1.    Amendments to Agreement.

(a)    The reference in the first recital to “X4 Pharmaceuticals, LLC, a Massachusetts limited liability company” is hereby deleted and “X4 Pharmaceuticals, INC., a Delaware corporation” is hereby inserted in lieu thereof

(b)    All references in the Agreement to “X4 Pharmaceuticals, LLC” are hereby deleted and “X4 Pharmaceuticals, INC.” is hereby inserted in lieu thereof.

(c)    Section 6.2 of the Agreement is hereby deleted in its entirety and the following is hereby inserted in lieu thereof:

“6.2    X4 First Financing Fee.

6.2.1    No later than [***] after the closing of the X4 First Financing, X4 shall pay Genzyme an upfront amount equal to Three Hundred Thousand Dollars ($300,000) (the “First Financing Fee”). The payment of the First Financing Fee shall be [***].

6.2.2    X4 shall have the right in its sole discretion to extend the Financing Exclusivity Period (as defined in Section 12.1.1 below) during the term thereof by providing written notice to Genzyme (the “Financing Exclusivity Extension Notice”)

Page 1 of 3

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

(d)    Section 6.3.1(a) of the Agreement is hereby deleted in its entirety and the following is hereby inserted in lieu thereof:

“(a)    Initial Grant. No later than [***] after the closing of the X4 First Financing, X4 shall issue to Genzyme or to Genzyme’s designated Affiliate a number of shares of the Common Stock, $.001 par value per share, of X4 (“Shares”) that represents, on an as-converted basis, ten percent (10%) of the outstanding Shares of X4 immediately following the closing of the X4 First Financing (the “Initial Shares”).”

(e)    All references in the Agreement to “Units” and “Anti-Dilution Units” are hereby deleted and “Shares” and “Anti-Dilution Shares” is hereby inserted in lieu thereof.

(f)    All references in the Agreement to “Subject Units” are hereby deleted and “Subject Shares” is hereby inserted in lieu thereof.

(g)    Section 12.1 of the Agreement is hereby deleted in its entirety and the following is hereby inserted in lieu thereof:

“12.1    Termination upon Failure to Close the X4 First Financing.

12.1.1    Financing Exclusivity Period. X4 will use its Commercially Reasonable Efforts to consummate the X4 First Financing [***] (such period, as extended pursuant to this Section 12.1, the “Financing Exclusivity Period”).

12.1.2    Extension of Financing Exclusivity Period.

(a)    Extension Due to Payment of Financing Exclusivity Extension Payment. Upon the delivery by X4 of the Financing Exclusivity Extension Notice, the Financing Exclusivity Period shall automatically be extended [***].

(b)    Extension Due to Signed Term Sheet. In the event that X4 does not consummate the X4 First Financing on or before the expiration of the Financing Exclusivity Period (whether or not extended according to 12.1.2(a) above) and [***], then the Financing Exclusivity Period shall automatically be extended by [***].

12.1.3    Right to Terminate. In the event that X4 does not consummate the X4 First Financing on or before the expiration of the Financing Exclusivity Period and the Parties have not otherwise agreed in writing to further extend the Financing Exclusivity Period, this Agreement shall immediately terminate and Genzyme shall have no further obligations to X4 with respect to the Licensed Patent and Licensed Know-How and shall be free to negotiate and enter into any agreement with a Third Party concerning the Licensed Patents or the Licensed Know How.

(h)    All references in the Agreement to the “Execution Date” are hereby deleted and “Effective Date” is hereby inserted in lieu thereof.

Page 2 of 3

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

(i)    Schedule 1.58 to the Agreement is hereby deleted and replaced by the attached revised Schedule 1.58.

2.    Miscellaneous. The Parties hereby confirm and agree that, except as amended hereby, the Agreement remains in full force and effect and is a binding obligation of the Parties hereto. This Amendment may be executed in counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument.

This Amendment is executed by the authorized representatives of the Parties as of the date first written above.

Page 3 of 3

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

Schedule 1.58

[***]

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

Exhibit 10.7

GU Reference: 2016-058

EXCLUSIVE LICENSE AGREEMENT

BETWEEN

GEORGETOWN UNIVERSITY

AND

X4 PHARMACEUTICALS, INC.

This Exclusive License Agreement (hereinafter “Agreement”) is entered into and effective as of the 13th day of December, 2016 (hereinafter “Effective Date”), by and between GEORGETOWN UNIVERSITY, a Congressionally-chartered academic institution of higher education organized under the laws of the District of Columbia, having its principal place of business located at 37^th and O Streets, N.W., Washington, D.C. 20057 (hereinafter “GEORGETOWN” or “LICENSOR”), and X4 Pharmaceuticals, Inc., a corporation organized under the laws of the state of Delaware with offices located at 784 Memorial Drive, Suite 140, Cambridge, MA 02139 (hereinafter “LICENSEE”).

WHEREAS, GEORGETOWN AND LICENSEE are joint owners of certain Licensed Patents (as later defined herein) relating to Methods for Treating Cancer;

WHEREAS, Dr. Michael Atkins of GEORGETOWN is a co-inventor of the Licensed Patents;

WHEREAS, GEORGETOWN desires to have the Licensed Patents developed and commercialized to benefit the public and is willing to grant a license to LICENSEE hereunder;

WHEREAS, LICENSEE has represented to GEORGETOWN, to induce it to enter into this Agreement, that LICENSEE shall commit itself to a diligent program of exploiting the Licensed Patents so that public utilization shall result therefrom; and

WHEREAS, LICENSEE desires to obtain an exclusive license to GEORGETOWN’s joint ownership rights under the Licensed Patents upon the terms and conditions hereinafter set forth.

NOW, THEREFORE, the Parties agree as follows:

ARTICLE 1

Definitions

1

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

GU Reference: 2016-058

2

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

GU Reference: 2016-058

No other deductions shall be made for commissions paid to individuals whether they are with independent sales agencies or regularly employed by Licensee and on its payroll, or for the cost of collections. Licensed Products shall be considered “sold” [***] after billing or invoicing, or upon receipt of payment, whichever comes first, provided, however, that Licensed Products are actually shipped to unrelated Third Party customers. If a Licensed Product is distributed or invoiced for a discounted price substantially lower than customary in the trade, Net Sales shall be based on the customary amount billed for such Licensed Products. Without limiting the generality of the foregoing, transfers or dispositions of a Licensed Product for charitable, promotional (including samples), pre-clinical, clinical, or regulatory purposes will be excluded from Net Sales.

3

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

GU Reference: 2016-058

ARTICLE 2

Grant

4

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

GU Reference: 2016-058

ARTICLE 3

Sublicensing

5

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

GU Reference: 2016-058

ARTICLE 4

Reservation of Rights

ARTICLE 5

Licensee Diligence Obligations

6

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

GU Reference: 2016-058

ARTICLE 6

License Issue Fee and Milestone Payments

LICENSEE shall notify LICENSOR within [***] of LICENSEE’s determination of the occurrence of each such event and shall remit payment due under this Section within [***] of providing such notice to LICENSOR. Payments made pursuant to this Section 6.2 shall be nonrefundable and shall not be creditable against any other fee or payment. For purposes of this Section 6.2, [***]. For purposes of example and without limitation, [***]. Similarly, if, instead of [***]. In addition, [***] for purposes of this Section 6.2.

7

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

GU Reference: 2016-058

ARTICLE 7

Reports and Records of Licensee

(a)    Before First Commercial Sale. Prior to First Commercial Sale of any Licensed Product, LICENSEE shall deliver progress reports to LICENSOR annually, within [***] after the end of each calendar year. Such progress reports shall describe for each Licensed Product the LICENSEE’s work related to the development and testing of the Licensed Product and its efforts in obtaining any required government approvals for marketing the Licensed Product. Each report will include information sufficient to enable the LICENSOR to determine the LICENSEE’s progress in commercially developing the Licensed Product, including a summary of any material work completed by LICENSEE during such calendar year and any material work planned to be conducted by LICENSEE during the subsequent calendar year, with respect to the Licensed Product. In the event LICENSOR, in good faith, does not reasonably deem the information set forth in the report sufficient for determining progress in commercially developing the Licensed Product, LICENSEE shall modify the report accordingly.

(b)    Upon First Commercial Sale of a Licensed Product. LICENSEE shall report to LICENSOR the date of First Commercial Sale of a Licensed Product within [***] of its determination of the occurrence thereof.

8

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

GU Reference: 2016-058

(c)    After First Commercial Sale.    After the First Commercial Sale of a Licensed Product and until the payment of all of the milestone payments in Section 6.2 for such Licensed Product, LICENSEE shall deliver a report to LICENSOR within [***] days after December 31 of each year of Net Sales from the Sale of such Licensed Product during the immediately preceding [***] period containing the information concerning the immediately preceding [***] period, as further described in Section 7.2(b).

9

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

GU Reference: 2016-058

ARTICLE 8

Patents and Intellectual Property Rights

10

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

GU Reference: 2016-058

ARTICLE 9

Patent Marking

Patent Marking. LICENSEE shall mark the Licensed Products with a patent notice referring to the Licensed Patents in accordance with 35 U.S.C. §287.

11

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

GU Reference: 2016-058

ARTICLE 10

Enforcement of the Licensor’s Intellectual Property