SEC Form D filed by X4 Pharmaceuticals Inc.

The Securities and Exchange Commission has not necessarily reviewed the information in this filing and has not determined if it is accurate and complete. The reader should not assume that the information is accurate and complete.
		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM D Notice of Exempt Offering of Securities	OMB APPROVAL OMB Number: 3235-0076 Estimated average burden hours per response: 4.00

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1. Issuer's Identity

CIK (Filer ID Number)	Previous Names	None	Entity Type
0001501697	Arsanis, Inc.		X Corporation    Limited Partnership    Limited Liability Company    General Partnership    Business Trust    Other (Specify)
Name of Issuer
X4 Pharmaceuticals, Inc
Jurisdiction of Incorporation/Organization
DELAWARE
Year of Incorporation/Organization
X Over Five Years Ago    Within Last Five Years (Specify Year)    Yet to Be Formed

2. Principal Place of Business and Contact Information

Name of Issuer
X4 Pharmaceuticals, Inc
Street Address 1		Street Address 2
61 NORTH BEACON STREET		4TH FLOOR
City	State/Province/Country	ZIP/PostalCode	Phone Number of Issuer
BOSTON	MASSACHUSETTS	02134	857-529-8300

3. Related Persons

Last Name	First Name	Middle Name
Craig	Adam
Street Address 1	Street Address 2
X4 PHARMACEUTICALS, INC.	61 NORTH BEACON STREET, 4TH FLOOR
City	State/Province/Country	ZIP/PostalCode
BOSTON	MASSACHUSETTS	02134

Relationship:	X	Executive Officer	X	Director		Promoter

Clarification of Response (if Necessary):

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Last Name	First Name	Middle Name
Volpone	John
Street Address 1	Street Address 2
X4 PHARMACEUTICALS, INC.	61 NORTH BEACON STREET, 4TH FLOOR
City	State/Province/Country	ZIP/PostalCode
BOSTON	MASSACHUSETTS	02134

Relationship:	X	Executive Officer		Director		Promoter

Clarification of Response (if Necessary):

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Last Name	First Name	Middle Name
Arbet-Engels	Christophe
Street Address 1	Street Address 2
X4 PHARMACEUTICALS, INC.	61 NORTH BEACON STREET, 4TH FLOOR
City	State/Province/Country	ZIP/PostalCode
BOSTON	MASSACHUSETTS	02134

Relationship:	X	Executive Officer		Director		Promoter

Clarification of Response (if Necessary):

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Last Name	First Name	Middle Name
Baldry	Mark
Street Address 1	Street Address 2
X4 PHARMACEUTICALS, INC.	61 NORTH BEACON STREET, 4TH FLOOR
City	State/Province/Country	ZIP/PostalCode
BOSTON	MASSACHUSETTS	02134

Relationship:	X	Executive Officer		Director		Promoter

Clarification of Response (if Necessary):

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Last Name	First Name	Middle Name
DiBiase	Mary
Street Address 1	Street Address 2
X4 PHARMACEUTICALS, INC.	61 NORTH BEACON STREET, 4TH FLOOR
City	State/Province/Country	ZIP/PostalCode
BOSTON	MASSACHUSETTS	02134

Relationship:	X	Executive Officer		Director		Promoter

Clarification of Response (if Necessary):

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Last Name	First Name	Middle Name
Kirske	David
Street Address 1	Street Address 2
X4 PHARMACEUTICALS, INC.	61 NORTH BEACON STREET, 4TH FLOOR
City	State/Province/Country	ZIP/PostalCode
BOSTON	MASSACHUSETTS	02134

Relationship:	X	Executive Officer		Director		Promoter

Clarification of Response (if Necessary):

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Last Name	First Name	Middle Name
Bridger	Gary	J.
Street Address 1	Street Address 2
X4 PHARMACEUTICALS, INC.	61 NORTH BEACON STREET, 4TH FLOOR
City	State/Province/Country	ZIP/PostalCode
BOSTON	MASSACHUSETTS	02134

Relationship:		Executive Officer	X	Director		Promoter

Clarification of Response (if Necessary):

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Last Name	First Name	Middle Name
De Craecker	Francoise
Street Address 1	Street Address 2
X4 PHARMACEUTICALS, INC.	61 NORTH BEACON STREET, 4TH FLOOR
City	State/Province/Country	ZIP/PostalCode
BOSTON	MASSACHUSETTS	02134

Relationship:		Executive Officer	X	Director		Promoter

Clarification of Response (if Necessary):

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Last Name	First Name	Middle Name
Stewart	Murray	W.
Street Address 1	Street Address 2
X4 PHARMACEUTICALS, INC.	61 NORTH BEACON STREET, 4TH FLOOR
City	State/Province/Country	ZIP/PostalCode
BOSTON	MASSACHUSETTS	02134

Relationship:		Executive Officer	X	Director		Promoter

Clarification of Response (if Necessary):

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Last Name	First Name	Middle Name
Wyzga	Michael	S.
Street Address 1	Street Address 2
X4 PHARMACEUTICALS, INC.	61 NORTH BEACON STREET, 4TH FLOOR
City	State/Province/Country	ZIP/PostalCode
BOSTON	MASSACHUSETTS	02134

Relationship:		Executive Officer	X	Director		Promoter

Clarification of Response (if Necessary):

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4. Industry Group

Agriculture Banking & Financial Services    Commercial Banking    Insurance    Investing    Investment Banking    Pooled Investment Fund Is the issuer registered as an investment company under the Investment Company Act of 1940?    Yes    No    Other Banking & Financial Services    Business Services Energy    Coal Mining    Electric Utilities    Energy Conservation    Environmental Services    Oil & Gas    Other Energy

Health Care X Biotechnology    Health Insurance    Hospitals & Physicians    Pharmaceuticals    Other Health Care    Manufacturing Real Estate    Commercial    Construction    REITS & Finance    Residential    Other Real Estate

Retailing Restaurants Technology    Computers    Telecommunications    Other Technology Travel    Airlines & Airports    Lodging & Conventions    Tourism & Travel Services    Other Travel Other

5. Issuer Size

Revenue Range		OR	Aggregate Net Asset Value Range
	No Revenues			No Aggregate Net Asset Value
	$1 - $1,000,000			$1 - $5,000,000
	$1,000,001 - $5,000,000			$5,000,001 - $25,000,000
	$5,000,001 - $25,000,000			$25,000,001 - $50,000,000
	$25,000,001 - $100,000,000			$50,000,001 - $100,000,000
	Over $100,000,000			Over $100,000,000
X	Decline to Disclose			Decline to Disclose
	Not Applicable			Not Applicable

6. Federal Exemption(s) and Exclusion(s) Claimed (select all that apply)

Rule 504(b)(1) (not (i), (ii) or (iii))    Rule 504 (b)(1)(i)    Rule 504 (b)(1)(ii)    Rule 504 (b)(1)(iii) X Rule 506(b)    Rule 506(c)    Securities Act Section 4(a)(5)

Investment Company Act Section 3(c)    Section 3(c)(1)    Section 3(c)(9)      Section 3(c)(2)    Section 3(c)(10)    Section 3(c)(3)    Section 3(c)(11)    Section 3(c)(4)    Section 3(c)(12)    Section 3(c)(5)    Section 3(c)(13)    Section 3(c)(6)    Section 3(c)(14)    Section 3(c)(7)

7. Type of Filing

X	New Notice			Date of First Sale	2025-08-13				First Sale Yet to Occur
	Amendment

8. Duration of Offering

Does the Issuer intend this offering to last more than one year?

Yes X No

9. Type(s) of Securities Offered (select all that apply)

X	Equity		Pooled Investment Fund Interests
	Debt		Tenant-in-Common Securities
X	Option, Warrant or Other Right to Acquire Another Security		Mineral Property Securities
X	Security to be Acquired Upon Exercise of Option, Warrant or Other Right to Acquire Security		Other (describe)

10. Business Combination Transaction

Is this offering being made in connection with a business combination transaction, such as a merger, acquisition or exchange offer?

Yes X No

Clarification of Response (if Necessary):

11. Minimum Investment

Minimum investment accepted from any outside investor

$0

USD

12. Sales Compensation

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13. Offering and Sales Amounts

Total Offering Amount	$84,999,985	USD	or    Indefinite
Total Amount Sold	$84,999,985	USD
Total Remaining to be Sold	$0	USD	or    Indefinite

Clarification of Response (if Necessary):

14. Investors

	Select if securities in the offering have been or may be sold to persons who do not qualify as accredited investors, and enter the number of such non-accredited investors who already have invested in the offering.
	Regardless of whether securities in the offering have been or may be sold to persons who do not qualify as accredited investors, enter the total number of investors who already have invested in the offering:	18

15. Sales Commissions & Finder's Fees Expenses

Provide separately the amounts of sales commissions and finders fees expenses, if any. If the amount of an expenditure is not known, provide an estimate and check the box next to the amount.

Sales Commissions	$3,300,000	USD	Estimate
Finders' Fees	$0	USD	Estimate

Clarification of Response (if Necessary):

16. Use of Proceeds

Provide the amount of the gross proceeds of the offering that has been or is proposed to be used for payments to any of the persons required to be named as executive officers, directors or promoters in response to Item 3 above. If the amount is unknown, provide an estimate and check the box next to the amount.

$0

USD

Estimate

Clarification of Response (if Necessary):

Signature and Submission

Please verify the information you have entered and review the Terms of Submission below before signing and clicking SUBMIT below to file this notice.

Terms of Submission

In submitting this notice, each issuer named above is:

Notifying the SEC and/or each State in which this notice is filed of the offering of securities described and undertaking to furnish them, upon written request, in the accordance with applicable law, the information furnished to offerees.* Irrevocably appointing each of the Secretary of the SEC and, the Securities Administrator or other legally designated officer of the State in which the issuer maintains its principal place of business and any State in which this notice is filed, as its agents for service of process, and agreeing that these persons may accept service on its behalf, of any notice, process or pleading, and further agreeing that such service may be made by registered or certified mail, in any Federal or state action, administrative proceeding, or arbitration brought against the issuer in any place subject to the jurisdiction of the United States, if the action, proceeding or arbitration (a) arises out of any activity in connection with the offering of securities that is the subject of this notice, and (b) is founded, directly or indirectly, upon the provisions of:  (i) the Securities Act of 1933, the Securities Exchange Act of 1934, the Trust Indenture Act of 1939, the Investment Company Act of 1940, or the Investment Advisers Act of 1940, or any rule or regulation under any of these statutes, or (ii) the laws of the State in which the issuer maintains its principal place of business or any State in which this notice is filed. Certifying that, if the issuer is claiming a Regulation D exemption for the offering, the issuer is not disqualified from relying on Rule 504 or Rule 506 for one of the reasons stated in Rule 504(b)(3) or Rule 506(d).

Each Issuer identified above has read this notice, knows the contents to be true, and has duly caused this notice to be signed on its behalf by the undersigned duly authorized person.

For signature, type in the signer's name or other letters or characters adopted or authorized as the signer's signature.

Issuer	Signature	Name of Signer	Title	Date
X4 Pharmaceuticals, Inc	/s/ Natasha Thoren	Natasha Thoren	Chief Legal Officer	2025-08-25

Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB number.

* This undertaking does not affect any limits Section 102(a) of the National Securities Markets Improvement Act of 1996 ("NSMIA") [Pub. L. No. 104-290, 110 Stat. 3416 (Oct. 11, 1996)] imposes on the ability of States to require information. As a result, if the securities that are the subject of this Form D are "covered securities" for purposes of NSMIA, whether in all instances or due to the nature of the offering that is the subject of this Form D, States cannot routinely require offering materials under this undertaking or otherwise and can require offering materials only to the extent NSMIA permits them to do so under NSMIA's preservation of their anti-fraud authority.

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