Statement of Changes in Beneficial Ownership (Form 4)

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b). Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

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(Print or Type Responses)

1. Name and Address of Reporting Person * KIRSKE DAVID 2. Issuer Name and Ticker or Trading Symbol X4 Pharmaceuticals, Inc [XFOR] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) Chief Financial Officer (Last) (First) (Middle) C/O X4 PHARMACEUTICALS INC., 61 N BEACON STREET, 4TH FLOOR 3. Date of Earliest Transaction (Month/Day/Year) 08/12/2025 (Street) BOSTON, MA 02134 4. If Amendment, Date Original Filed (Month/Day/Year) 6. Individual or Joint/Group Filing (Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 08/14/2025 A 193,254(1) A $ 0 193,254 D

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Stock Option (right to buy)

$1.42

08/12/2025

A

1,073,249

(2)

08/12/2035

Common Stock

1,073,249

$ 0

1,073,249

D

Stock Option (right to buy)

$3.14

08/14/2025

A

352,800

(2)

08/14/2035

Common Stock

352,800

$ 0

352,800

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
KIRSKE DAVID C/O X4 PHARMACEUTICALS INC. 61 N BEACON STREET, 4TH FLOOR BOSTON, MA 02134			Chief Financial Officer

Signatures

/s/ Brian Bowersox, Attorney-In-Fact		08/14/2025
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	Represents restricted stock units (RSUs) granted to the Reporting Person. One third of the RSUs shall vest on February 12, 2026, with the remainder vesting in equal installments in each successive quarter thereafter for a period of 12 months, subject to the Reporting Person continuing to provide services through each such date and contingent upon approval of the grant at the Issuer's 2026 Annual Meeting of Stockholders.
(2)	One half of the shares subject to the option shall vest on February 12, 2026, with the remainder vesting in equal installments in each successive month thereafter for a period of 12 months, subject to the Reporting Person continuing to provide services through each such date; provided that one half of the shares subject to the option shall vest immediately upon achievement of certain performance-based milestones prior to February 12, 2026.

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