Document

X4 Pharmaceuticals, Inc.
61 North Beacon Street, 4th Floor
Boston, MA 02134

July 7, 2021

Via Edgar
United States Securities and Exchange Commission
Division of Corporation Finance
100 F Street, N.E.
Washington, D.C. 20549
Attn:    Jeffrey Gabor

RE:    X4 Pharmaceuticals, Inc.
    Registration Statement on Form S-3
    File No. 333-257422

    Acceleration Request
        Requested Date:    July 9, 2021
        Requested Time:    4:00 p.m. Eastern Time

Ladies and Gentlemen:
Pursuant to Rule 461 under the Securities Exchange Act of 1933, as amended, the undersigned registrant hereby requests that the Securities and Exchange Commission take appropriate action to cause the above-referenced Registration Statement on Form S-3 (File No. 333-257422) (the “Registration Statement”) to become effective at 4:00 p.m. Eastern Time on Friday, July 9, 2021, or as soon thereafter as is practicable.
Once the Registration Statement has been declared effective, please orally confirm that event with Daniel I. Goldberg of Cooley LLP, counsel to the registrant, at (212) 479-6722.

[Signature page follows]

https://cdn.kscope.io/d29438fa8accc7f0f6153c8fa039a479-image_2.jpg

https://cdn.kscope.io/d29438fa8accc7f0f6153c8fa039a479-image_0.jpg

Sincerely,
X4 Pharmaceuticals, Inc.


By: __    /s/Adam S. Mostafa        
    Adam S. Mostafa
Chief Financial Officer


cc:    Paula Ragan, Ph.D., Chief Executive Officer, X4 Pharmaceuticals, Inc.    
    Derek Meisner, General Counsel, X4 Pharmaceuticals, Inc.
Daniel I. Goldberg, Cooley LLP
Courtney T. Thorne, Cooley LLP


https://cdn.kscope.io/d29438fa8accc7f0f6153c8fa039a479-image_2.jpg