ASNS / Actelis Networks, Inc. - Pengajuan SECLaporan Tahunan, Pernyataan Proksi

Actelis Networks, Inc.
US ˙ NasdaqCM ˙ US00503R4092

Mga Batayang Estadistika
LEI 549300R0UFVPXWP86U94
CIK 1501697
SEC Filings
All companies that sell securities in the United States must register with the Securities and Exchange Commission (SEC) and file reports on a regular basis. These reports include company annual reports (10K, 10Q), news updates (8K), investor presentations (found in 8Ks), insider trades (form 4), ownership reports (13D, and 13G), and reports related to the specific securities sold, such as registration statements and prospectus. This page shows recent SEC filings related to Actelis Networks, Inc.
SEC Filings (Chronological Order)
Halaman ini menyediakan daftar lengkap dan kronologis dari Pengajuan SEC, tidak termasuk pengajuan kepemilikan yang kami sediakan di tempat lain.
August 25, 2025 8-K

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): August 22, 2025 X4 PHARMACEUTICAL

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): August 22, 2025 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commissio

August 13, 2025 EX-99.1

X4 Pharmaceuticals Announces Closing of Upsized $85 Million Private Placement

Exhibit 99.1 X4 Pharmaceuticals Announces Closing of Upsized $85 Million Private Placement BOSTON, Mass., August 13, 2025 – X4 Pharmaceuticals (Nasdaq: XFOR), a company driven to improve the lives of people with rare diseases of the immune system, today closed an upsized private placement of 11,040,776 shares of common stock and pre-funded warrants to purchase 48,852,772 shares of common stock for

August 13, 2025 8-K

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): August 12, 2025 X4 PHARMACEUTICAL

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): August 12, 2025 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commissio

August 13, 2025 EX-10.1

[Remainder of Page Intentionally Left Blank.]

SECURITIES PURCHASE AGREEMENT EXHIBIT 10.1 This SECURITIES PURCHASE AGREEMENT (this “Agreement”) is dated as of August 12, 2025 by and among X4 Pharmaceuticals, Inc., a Delaware corporation (the “Company”), and each of the entities listed on Exhibit A attached to this Agreement (each, an “Investor” and together, the “Investors”). WHEREAS, the Company and the Investors are executing and delivering

August 13, 2025 EX-10.2

[Signature Page Follows]

REGISTRATION RIGHTS AGREEMENT EXHIBIT 10.2 THIS REGISTRATION RIGHTS AGREEMENT (this “Agreement”), dated as of August 12, 2025, is entered into by and among X4 PHARMACEUTICALS, INC., a Delaware corporation (the “Company”), and the several investors signatory hereto (individually as an “Investor” and collectively together with their respective permitted assigns, the “Investors”). Capitalized terms u

August 12, 2025 EX-4.1

[FORM OF] PRE-FUNDED WARRANT TO PURCHASE COMMON STOCK

Exhibit 4.1 THIS WARRANT AND THE SHARES OF COMMON STOCK ISSUABLE UPON THE EXERCISE OF THIS WARRANT (THE “SECURITIES”) HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES ACT”), OR THE SECURITIES LAWS OF ANY STATE OF THE UNITED STATES. THE SECURITIES HAVE BEEN ACQUIRED FOR INVESTMENT AND MAY NOT BE SOLD, TRANSFERRED OR ASSIGNED UNLESS (I) SUCH SECURITIES HAVE BEEN

August 12, 2025 EX-10.3

AMENDMENT NO. 1 TO X4 PHARMACEUTICALS, INC. AMENDED AND RESTATED 2019 INDUCEMENT EQUITY INCENTIVE PLAN

Exhibit 10.3 AMENDMENT NO. 1 TO X4 PHARMACEUTICALS, INC. AMENDED AND RESTATED 2019 INDUCEMENT EQUITY INCENTIVE PLAN A.The X4 Pharmaceuticals, Inc. Amended and Restated 2019 Inducement Equity Incentive Plan (the “Plan”) is hereby amended by deleting Section 4(a)(1) and substituting therefore the following: “(1) Authorized Number of Shares. Subject to adjustment under Section 9, Awards may be made u

August 12, 2025 EX-10.2

REGISTRATION RIGHTS AGREEMENT

Exhibit 10.2 REGISTRATION RIGHTS AGREEMENT THIS REGISTRATION RIGHTS AGREEMENT (this “Agreement”), dated as of August 11, 2025, is entered into by and among X4 PHARMACEUTICALS, INC., a Delaware corporation (the “Company”), and the several investors signatory hereto (individually as an “Investor” and collectively together with their respective permitted assigns, the “Investors”). Capitalized terms u

August 12, 2025 EX-10.1

SECURITIES PURCHASE AGREEMENT

Exhibit 10.1 SECURITIES PURCHASE AGREEMENT This SECURITIES PURCHASE AGREEMENT (this “Agreement”) is dated as of August 11, 2025 by and among X4 Pharmaceuticals, Inc., a Delaware corporation (the “Company”), and each of the entities listed on Exhibit A attached to this Agreement (each, an “Investor” and together, the “Investors”). WHEREAS, the Company and the Investors are executing and delivering

August 12, 2025 8-K

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): August 11, 2025 X4 PHARMACEUTICAL

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): August 11, 2025 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commissio

August 12, 2025 EX-99.1

$60 million PIPE financing led by Coastlands Capital, Bain Capital Life Sciences and New Enterprise Associates Newly appointed board and management team includes Dr. Adam Craig as Executive Chairman, John Volpone as President and David Kirske as Chie

Exhibit 99.1 X4 Pharmaceuticals Announces $60 Million Equity Financing with Concurrent Changes in Management and Board Leadership $60 million PIPE financing led by Coastlands Capital, Bain Capital Life Sciences and New Enterprise Associates Newly appointed board and management team includes Dr. Adam Craig as Executive Chairman, John Volpone as President and David Kirske as Chief Financial Officer

August 8, 2025 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2025 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-38295 X4 PHARMAC

June 23, 2025 8-K

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 (Data of earliest event reported): June 23, 2025 X4 PHARMACEUTICALS,

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 (Data of earliest event reported): June 23, 2025 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission

June 23, 2025 EX-10.2

Registration Rights Agreement, dated June 23, 2025, by and between X4 Pharmaceuticals, Inc. and Lincoln Park Capital Fund, LLC.

EXHIBIT 10.2 REGISTRATION RIGHTS AGREEMENT THIS REGISTRATION RIGHTS AGREEMENT (this “Agreement”), dated as of June 23, 2025, is entered into by and between X4 PHARMACEUTICALS, INC., a Delaware corporation (the “Company”), and LINCOLN PARK CAPITAL FUND, LLC, an Illinois limited liability company (together with its permitted assigns, the “Investor”). Capitalized terms used herein and not otherwise d

June 23, 2025 EX-10.1

Purchase Agreement, dated June 23, 2025, by and between X4 Pharmaceuticals, Inc. and Lincoln Park Capital Fund, LLC.

EXHIBIT 10.1 PURCHASE AGREEMENT THIS PURCHASE AGREEMENT (the "Agreement"), dated as of June 23, 2025, is made by and between X4 PHARMACEUTICALS, INC., a Delaware corporation (the "Company"), and LINCOLN PARK CAPITAL FUND, LLC, an Illinois limited liability company (the "Investor"). WHEREAS: Subject to the terms and conditions set forth in this Agreement, the Company wishes to sell to the Investor,

June 23, 2025 424B5

$40,000,000 and 137,099 Shares of Common Stock

Filed Pursuant to Rule 424(b)(5) PROSPECTUS SUPPLEMENT Registration No. 333-273961 (To Prospectus dated August 24, 2023) $40,000,000 and 137,099 Shares of Common Stock This prospectus supplement, which supplements the accompanying prospectus, relates to the issuance and sale of up to $40,000,000 of shares of our common stock, par value $0.001 per share, or the Purchase Shares, that we may sell to

June 11, 2025 8-K

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): June 11, 2025 (June 9, 2025) X4 P

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): June 11, 2025 (June 9, 2025) X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporatio

May 1, 2025 EX-99.2

ABBEY Living with Chronic Neutropenia Driving progress for patients with chronic neutropenic disorders Investor Deck – May 2025 Exhibit 99.2 This presentation including any printed or electronic copy of these slides, the talks given by the presenters

ABBEY Living with Chronic Neutropenia Driving progress for patients with chronic neutropenic disorders Investor Deck – May 2025 Exhibit 99.

May 1, 2025 EX-10.16

Amended and Restated Non-Employee Director Compensation Policy, dated February 13, 2024

Exhibit 10.16 X4 PHARMACEUTICALS, INC. AMENDED AND RESTATED DIRECTOR COMPENSATION POLICY (Last modified: February 13, 2024) The Board of Directors (the “Board”) of X4 Pharmaceuticals, Inc. (the “Company”), has approved the following Amended and Restated Director Compensation Policy under which the Company’s non-employee directors shall receive the following compensation for their service as member

May 1, 2025 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2025 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-38295 X4 PHARMA

May 1, 2025 8-K

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): May 1, 2025 X4 PHARMACEUTICALS, I

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): May 1, 2025 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission Fi

May 1, 2025 EX-99.1

X4 Pharmaceuticals Reports First Quarter 2025 Financial Results and Provides Corporate Updates 4WARD Phase 3 chronic neutropenia trial in full swing; full enrollment on track for 3Q or 4Q 2025 and top-line data in 2H 2026 Additional analyses of mavor

Exhibit 99.1 X4 Pharmaceuticals Reports First Quarter 2025 Financial Results and Provides Corporate Updates 4WARD Phase 3 chronic neutropenia trial in full swing; full enrollment on track for 3Q or 4Q 2025 and top-line data in 2H 2026 Additional analyses of mavorixafor clinical trial data increase confidence in successful outcome of 4WARD trial XOLREMDI® net U.S. revenues $3.5 million since May 20

April 25, 2025 DEFA14A

SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Definitive Proxy Statement ☒ Definitive Additional Materials ☐ Soliciting Material Pursuant to § 240.

April 25, 2025 DEF 14A

SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☒ Definitive Proxy Statement ☐ Definitive Additional Materials ☐ Soliciting Material Pursuant to § 240.

April 24, 2025 EX-3.1

Certificate of Amendment to the Restated Certificate of Incorporation of X4 Pharmaceuticals, Inc.

Exhibit 3.1 CERTIFICATE OF AMENDMENT TO RESTATED CERTIFICATE OF INCORPORATION OF X4 PHARMACEUTICALS, INC. (originally incorporated on August 2, 2010) X4 Pharmaceuticals, Inc., a corporation organized and existing under and by virtue of the General Corporation Law of the State of Delaware (the “Corporation”), does hereby certify as follows: 1.This Certificate of Amendment (this “Certificate of Amen

April 24, 2025 8-K

Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year, Financial Statements and Exhibits, Other Events

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): April 24, 2025 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission

April 24, 2025 EX-99.1

X4 Pharmaceuticals Announces Reverse Stock Split

Exhibit 99.1 X4 Pharmaceuticals Announces Reverse Stock Split BOSTON, Mass., April 24, 2025 – X4 Pharmaceuticals (Nasdaq: XFOR), a company driven to improve the lives of people with rare diseases of the immune system, today announced that its board of directors has determined to effect a one-for-thirty reverse stock split of the company’s Common Stock, par value $0.001 per share. The reverse stock

April 18, 2025 8-K

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): April 17, 2025 X4 PHARMACEUTICALS

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): April 17, 2025 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission

March 26, 2025 EX-10.38

License Agreement and Supply Agreement, dated as of January 13, 2025, by and between X4 Pharmaceuticals Inc. and Norgine Pharma UK Limited

EXHIBIT 10.38 [***] = CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT, MARKED BY BRACKETS, HAS BEEN OMITTED BECAUSE THE INFORMATION (I) IS NOT MATERIAL AND (II) WOULD BE COMPETITIVELY HARMFUL IF PUBLICALLY DISCLOSED. Dated 11 January 2025 X4 PHARMACEUTICALS, INC. and NORGINE PHARMA UK LIMITED LICENSE AND SUPPLY AGREEMENT TABLE OF CONTENTS Page 1. Definitions 1 2. Grant Of License; Obli

March 26, 2025 S-8

As filed with the Securities and Exchange Commission on March 25, 2025

As filed with the Securities and Exchange Commission on March 25, 2025 Registration No.

March 26, 2025 EX-FILING FEES

Filing Fee Table

Exhibit 107 Calculation of Filing Fee Table Form S-8 (Form Type) X4 Pharmaceuticals, Inc.

March 26, 2025 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) x ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2024 or o ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-38295 X4 PHARMACEUTICALS

March 26, 2025 EX-10.35

Amendment No. 3 to Master Services Agreement, dated February 19, 2024, by and between X4 Pharmaceuticals Inc. and Aptuit (Oxford) Limited.

EXHIBIT 10.35 AMENDMENT NO. 3 TO MASTER SERVICES AGREEMENT This Amendment No. 3 (the “Amendment No. 3”) to the Master Services Agreement by and between X4 Pharmaceuticals, Inc., a Delaware corporation with a business address at 61 North Beacon Street, 4th Floor, Boston, Massachusetts 02134 USA (“X4”), and Aptuit (Oxford) Limited an Evotec company, incorporated in England and Wales, having an addre

March 25, 2025 EX-99.1

X4 Pharmaceuticals Reports Fourth Quarter and Full Year 2024 Financial Results and Provides Corporate Update

Exhibit 99.1 X4 Pharmaceuticals Reports Fourth Quarter and Full Year 2024 Financial Results and Provides Corporate Update Phase 3 4WARD trial in chronic neutropenia now activated at ~90% of targeted trial sites; full enrollment expected in 3Q or 4Q 2025; top-line data anticipated in 2H 2026 4WARD trial protocol refined, increasing confidence in successful outcome 2024 XOLREMDI® net revenues $2.6 m

March 25, 2025 8-K

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 25, 2025 X4 PHARMACEUTICALS

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 25, 2025 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission

March 24, 2025 DEF 14A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☒ Definitive

March 14, 2025 PRE 14A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☒ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Definitive

March 3, 2025 8-K

Other Events

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 3, 2025 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission

February 6, 2025 8-K

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): February 6, 2025 X4 PHARMACEUTICA

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): February 6, 2025 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commissi

February 6, 2025 EX-99.1

X4 Pharmaceuticals Announces Strategic Restructuring to Drive Value and Maximize Opportunity for Mavorixafor in Chronic Neutropenia Full enrollment in ongoing global, pivotal Phase 3 clinical trial in chronic neutropenia on track for mid-2025 Right-s

Exhibit 99.1 X4 Pharmaceuticals Announces Strategic Restructuring to Drive Value and Maximize Opportunity for Mavorixafor in Chronic Neutropenia Full enrollment in ongoing global, pivotal Phase 3 clinical trial in chronic neutropenia on track for mid-2025 Right-sizing commercial efforts to optimize XOLREMDI promotion and support U.S. WHIM syndrome community Restructuring impact expected to extend

January 16, 2025 EX-FILING FEES

Filing Fee Table

Exhibit 107 Calculation of Filing Fee Table Form S-8 (Form Type) X4 Pharmaceuticals, Inc.

January 16, 2025 S-8

As filed with the Securities and Exchange Commission on January 16, 2025

As filed with the Securities and Exchange Commission on January 16, 2025 Registration No.

January 13, 2025 EX-99.2

Enabling a better future for people with rare immune disorders PROGRESS PATIENTS January 2025 Exhibit 99.2 2 Forward-Looking Statements This presentation including any printed or electronic copy of these slides, the talks given by the presenters, the

Enabling a better future for people with rare immune disorders PROGRESS PATIENTS January 2025 Exhibit 99.

January 13, 2025 8-K

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): January 13, 2025 X4 PHARMACEUTICA

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): January 13, 2025 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commissi

January 13, 2025 EX-99.1

X4 Pharmaceuticals and Norgine Enter into Exclusive Licensing Agreement to Commercialize Mavorixafor in Europe, Australia, and New Zealand X4 to receive a €28.5 million upfront payment and up to €226 million in potential regulatory and commercial mil

Exhibit 99.1 X4 Pharmaceuticals and Norgine Enter into Exclusive Licensing Agreement to Commercialize Mavorixafor in Europe, Australia, and New Zealand X4 to receive a €28.5 million upfront payment and up to €226 million in potential regulatory and commercial milestone payments in addition to tiered, double-digit royalties up to the mid-twenties Upfront non-dilutive funds strengthen X4’s balance s

December 23, 2024 CORRESP

December 23, 2024 U.S. Securities and Exchange Commission Division of Corporation Finance Office of Life Sciences 100 F Street, N.E. Washington, D.C. 20549 Attention: Vanessa Robertson/Daniel Gordon Re: X4 Pharmaceuticals, Inc. Form 10-K for the fisc

December 23, 2024 U.S. Securities and Exchange Commission Division of Corporation Finance Office of Life Sciences 100 F Street, N.E. Washington, D.C. 20549 Attention: Vanessa Robertson/Daniel Gordon Re: X4 Pharmaceuticals, Inc. Form 10-K for the fiscal year ended December 31, 2023 Form 10-Q for the quarterly period ended September 30, 2024 File No. 001-38295 Ladies and Gentlemen: This letter sets

November 13, 2024 8-K

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): November 13, 2024 X4 PHARMACEUTIC

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): November 13, 2024 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commiss

November 13, 2024 EX-99.1

X4 Pharmaceuticals Reports Third Quarter 2024 Financial Results and Provides Corporate Update Positive results from completed Phase 2 study of mavorixafor in chronic neutropenia (CN) announced today Pivotal Phase 3 trial of mavorixafor in CN on track

Exhibit 99.1 X4 Pharmaceuticals Reports Third Quarter 2024 Financial Results and Provides Corporate Update Positive results from completed Phase 2 study of mavorixafor in chronic neutropenia (CN) announced today Pivotal Phase 3 trial of mavorixafor in CN on track to fully enroll in mid-2025 U.S. launch of XOLREMDI® (mavorixafor) in WHIM underway; submission of Marketing Authorization Application (

November 13, 2024 EX-99.1

X4 Pharmaceuticals Announces Positive Results from Completed Six-Month Phase 2 Trial of Mavorixafor in Chronic Neutropenia (CN) Mavorixafor durably and meaningfully elevated participants’ mean absolute neutrophil counts (ANC) Mavorixafor enabled subs

Exhibit 99.1 X4 Pharmaceuticals Announces Positive Results from Completed Six-Month Phase 2 Trial of Mavorixafor in Chronic Neutropenia (CN) Mavorixafor durably and meaningfully elevated participants’ mean absolute neutrophil counts (ANC) Mavorixafor enabled substantial reductions in G-CSF dosing while maintaining mean ANC at normal levels Phase 2 study results and new analysis confirming function

November 13, 2024 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2024 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-38295 X4 PH

November 13, 2024 8-K

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): November 13, 2024 X4 PHARMACEUTIC

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): November 13, 2024 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commiss

November 13, 2024 EX-99.2

3Q 2024 Business Update & Phase 2 Chronic Neutropenia Study Results November 13, 2024 Exhibit 99.2 Forward-Looking Statements This presentation including any printed or electronic copy of these slides, the talks given by the presenters, the informati

a992corporatepresentatio 3Q 2024 Business Update & Phase 2 Chronic Neutropenia Study Results November 13, 2024 Exhibit 99.

October 4, 2024 EX-FILING FEES

Filing Fee Table

Exhibit 107 Calculation of Filing Fee Table Form S-8 (Form Type) X4 Pharmaceuticals, Inc.

October 4, 2024 S-8

As filed with the Securities and Exchange Commission on October 4, 2024

As filed with the Securities and Exchange Commission on October 4, 2024 Registration No.

August 16, 2024 8-K

Notice of Delisting or Failure to Satisfy a Continued Listing Rule or Standard; Transfer of Listing

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): August 13, 2024 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commissio

August 9, 2024 8-K

Regulation FD Disclosure

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): August 8, 2024 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission

August 8, 2024 EX-10.2

Non-Employee Director Deferred Compensation Policy

EXHIBIT 10.2 RULES AND CONDITIONS FOR THE X4 PHARMACEUTICALS, INC. NON-EMPLOYEE DIRECTORS’ DEFERRED COMPENSATION PROGRAM (THE “PROGRAM”) The following rules and conditions have been adopted by the Board of Directors of X4 Pharmaceuticals, Inc. (the “Company”) to govern the deferral of Restricted Stock Units by non- employee directors of the Company (each, a “Non-Employee Director” and collectively

August 8, 2024 EX-99.1

X4 Pharmaceuticals Reports Second Quarter 2024 Financial Results and Provides Corporate Updates First U.S. commercial sales of XOLREMDI™ (mavorixafor) following April 2024 FDA approval Positive interim data from Phase 2 trial of mavorixafor in chroni

Exhibit 99.1 X4 Pharmaceuticals Reports Second Quarter 2024 Financial Results and Provides Corporate Updates First U.S. commercial sales of XOLREMDI™ (mavorixafor) following April 2024 FDA approval Positive interim data from Phase 2 trial of mavorixafor in chronic neutropenia; full trial results expected in November 2024 Initiated global, pivotal Phase 3 trial of mavorixafor in chronic neutropenia

August 8, 2024 EX-10.3

Insider Trading Policy

EXHIBIT 10.3 X4 PHARMACEUTICALS, INC. AMENDED AND RESTATED INSIDER TRADING POLICY (AS OF JUNE 28, 2024) INTRODUCTION During the course of your relationship with X4 Pharmaceuticals, Inc. (the “Company”), you may receive material information that is not yet publicly available (“material nonpublic information” or “MNPI”) about the Company or other publicly traded companies with which the Company has

August 8, 2024 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2024 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-38295 X4 PHARMAC

August 8, 2024 8-K

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): August 8, 2024 X4 PHARMACEUTICALS

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): August 8, 2024 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission

August 8, 2024 EX-10.1

Asset Purchase Agreement, dated May 8, 2024

EXHIBIT 10.1 CERTAIN CONFIDENTIAL INFORMATION MARKED BY [***] HAS BEEN EXCLUDED FROM THIS EXHIBIT BECAUSE IT IS BOTH NOT MATERIAL AND IS THE TYPE THAT THE REGISTRANT TREATS AS PRIVATE OR CONFIDENTIAL ASSET PURCHASE AGREEMENT BY AND BETWEEN [***] AND X4 PHARMACEUTICALS, INC. MAY 8, 2024 i TABLE OF CONTENTS PAGE ARTICLE 1 DEFINITIONS ..................................................................

July 19, 2024 8-K

Regulation FD Disclosure

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): July 19, 2024 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission

June 27, 2024 8-K

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): June 27, 2024 X4 PHARMACEUTICALS,

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): June 27, 2024 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission

June 27, 2024 EX-99.2

1 Mavorixafor in Chronic Neutropenia Interim data from ongoing Phase 2 clinical trial Investor Event June 27, 2024 Exhibit 99.2 22 Forward-Looking Statements This presentation including any printed or electronic copy of these slides, the talks given

ex992x4corporatepresent 1 Mavorixafor in Chronic Neutropenia Interim data from ongoing Phase 2 clinical trial Investor Event June 27, 2024 Exhibit 99.

June 27, 2024 EX-99.1

X4 Pharmaceuticals Announces Positive Interim Clinical Data from Ongoing Six-Month Phase 2 Trial of Mavorixafor in Chronic Neutropenia (CN) and Initiation of Pivotal Phase 3 CN Trial 100% of evaluable participants at Month 6 achieved target absolute

Exhibit 99.1 X4 Pharmaceuticals Announces Positive Interim Clinical Data from Ongoing Six-Month Phase 2 Trial of Mavorixafor in Chronic Neutropenia (CN) and Initiation of Pivotal Phase 3 CN Trial 100% of evaluable participants at Month 6 achieved target absolute neutrophil count (ANC) increase with once-daily, oral mavorixafor +/- stable-dose G-CSF as of the interim analysis data cut-off date Dura

June 11, 2024 8-K

Submission of Matters to a Vote of Security Holders

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): June 10, 2024 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission

May 22, 2024 8-K

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): May 22, 2024 X4 PHARMACEUTICALS,

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): May 22, 2024 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission F

May 22, 2024 EX-99.1

Enabling a better future for people with rare immune disorders PROGRESS PATIENTS May 2024 Exhibit 99.1 2 Forward-Looking Statements This presentation including any printed or electronic copy of these slides, the talks given by the presenters, the inf

exhibit991x4investordeck Enabling a better future for people with rare immune disorders PROGRESS PATIENTS May 2024 Exhibit 99.

May 9, 2024 8-K

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): May 8, 2024 X4 PHARMACEUTICALS, I

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): May 8, 2024 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission Fi

May 9, 2024 EX-99.1

X4 Pharmaceuticals Announces $125 Million Capital Infusion from $105 Million Sale of Priority Review Voucher and $20 Million Drawdown from Existing Loan Facility $125 million of non-dilutive capital extends projected cash runway into late 2025, exclu

Exhibit 99.1 X4 Pharmaceuticals Announces $125 Million Capital Infusion from $105 Million Sale of Priority Review Voucher and $20 Million Drawdown from Existing Loan Facility $125 million of non-dilutive capital extends projected cash runway into late 2025, excluding expected commercial sales from XOLREMDI™ (mavorixafor) XOLREMDI, the first drug indicated in patients with WHIM syndrome, received U

May 7, 2024 EX-99.1

X4 Pharmaceuticals Reports First-Quarter 2024 Financial Results and Provides Corporate Updates U.S. launch underway for XOLREMDI™ (mavorixafor) in WHIM syndrome XOLREMDI Phase 3 4WHIM clinical trial data published online in Blood, the journal of the

Exhibit 99.1 X4 Pharmaceuticals Reports First-Quarter 2024 Financial Results and Provides Corporate Updates U.S. launch underway for XOLREMDI™ (mavorixafor) in WHIM syndrome XOLREMDI Phase 3 4WHIM clinical trial data published online in Blood, the journal of the American Society of Hematology Presentation of interim clinical data from the ongoing mavorixafor Phase 2 trial in chronic neutropenia ex

May 7, 2024 8-K

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): May 7, 2024 X4 PHARMACEUTICALS, I

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): May 7, 2024 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission Fi

May 7, 2024 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2024 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-38295 X4 PHARMA

April 29, 2024 8-K

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): April 29, 2024 X4 PHARMACEUTICALS

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): April 29, 2024 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission

April 29, 2024 EX-99.1

PROGRESS PATIENTS Investor Call April 29, 2024 EXHIBIT 99.1 2 Forward-Looking Statements This presentation including any printed or electronic copy of these slides, the talks given by the presenters, the information communicated during any delivery o

ex991investordeck2024-04 PROGRESS PATIENTS Investor Call April 29, 2024 EXHIBIT 99.

April 29, 2024 ARS

X4 PHARMACEUTICALS, INC. 2023 ANNUAL REPORT UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) x ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended

x4pharmaceuticalsincannu X4 PHARMACEUTICALS, INC. 2023 ANNUAL REPORT UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) x ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2023 or o ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transitio

April 29, 2024 DEFA14A

SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Definitive Proxy Statement ☒ Definitive Additional Materials ☐ Soliciting Material Pursuant to § 240.

April 29, 2024 DEF 14A

SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☒ Definitive Proxy Statement ☐ Definitive Additional Materials ☐ Soliciting Material Pursuant to § 240.

April 29, 2024 8-K

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): April 29, 2024 X4 PHARMACEUTICALS

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): April 29, 2024 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission

April 29, 2024 EX-99.1

X4 Pharmaceuticals Announces FDA Approval of XOLREMDI™ (mavorixafor) Capsules, First Drug Indicated in Patients with WHIM Syndrome XOLREMDI targets CXCR4 pathway dysfunction, the underlying cause of WHIM syndrome Breakthrough Therapy approval follows

Exhibit-99.1 X4 Pharmaceuticals Announces FDA Approval of XOLREMDI™ (mavorixafor) Capsules, First Drug Indicated in Patients with WHIM Syndrome XOLREMDI targets CXCR4 pathway dysfunction, the underlying cause of WHIM syndrome Breakthrough Therapy approval follows Priority Review of 4WHIM Phase 3 clinical trial data X4 granted Rare Pediatric Disease Priority Review Voucher (PRV) concurrent with app

April 5, 2024 8-K

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): April 5, 2024 X4 PHARMACEUTICALS,

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): April 5, 2024 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission

April 1, 2024 8-K

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): April 1, 2024 X4 PHARMACEUTICALS,

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): April 1, 2024 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission

March 21, 2024 8-K

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 21, 2024 X4 PHARMACEUTICALS

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 21, 2024 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission

March 21, 2024 EX-97.1

Incentive Compensation Recoupment Policy

EX 97.1 X4 Pharmaceuticals, Inc. Incentive Compensation Recoupment Policy 1.Introduction The Compensation Committee (the “Compensation Committee”) of the Board of Directors (the “Board”) of X4 PHARMACEUTICALS, INC., a Delaware corporation (the “Company”), has determined that it is in the best interests of the Company and its stockholders to adopt this Incentive Compensation Recoupment Policy (this

March 21, 2024 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) x ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2023 or o ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-38295 X4 PHARMACEUTICALS

March 21, 2024 EX-99.1

X4 Pharmaceuticals Reports Fourth-Quarter and Full-Year 2023 Financial Results and Provides Corporate Update Launch preparations underway in anticipation of possible U.S. approval of mavorixafor for WHIM syndrome; U.S. PDUFA target action date set fo

Exhibit 99.1 X4 Pharmaceuticals Reports Fourth-Quarter and Full-Year 2023 Financial Results and Provides Corporate Update Launch preparations underway in anticipation of possible U.S. approval of mavorixafor for WHIM syndrome; U.S. PDUFA target action date set for April 30, 2024 Additional Phase 2 clinical data and initiation of global Phase 3 clinical trial of mavorixafor for the treatment of cer

March 21, 2024 EX-10.37

Amendment No. 3 to Master Services Agreement, dated August 3, 2023, by and between X4 Pharmaceuticals Inc., and Catalent.

EXHIBIT 10.37 AMENDMENT No. 3 TO THE MASTER SERVICES AGREEMENT This Amendment No. 3 (“Amendment 3”) to the Agreement (as defined below) is made as of August 3, 2023 (“Amendment 3 Effective Date”), by and between Catalent Greenville, Inc., a North Carolina corporation, having a principal place of business at 1240 Sugg Parkway, Greenville, NC 27834 (“Catalent”), and X4 Pharmaceuticals Inc., a Delawa

February 14, 2024 SC 13G

XFOR / X4 Pharmaceuticals, Inc. / ACORN BIOVENTURES, L.P. Passive Investment

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. )* X4 Pharmaceuticals, Inc. (Name of Issuer) Common Stock, $0.001 par value per share (Title of Class of Securities) 98420X103 (CUSIP Number) June 30, 2022, December 31, 2022 and December 31, 2023 (Date of Event Which Requires Filing of this Statement) Check the appropria

February 14, 2024 EX-99.1

Joint Filing Agreement

EXHIBIT 99.1 Joint Filing Agreement The undersigned hereby agree that they are filing this statement jointly pursuant to Rule 13d-1(k)(1). Each of them is responsible for the timely filing of such Schedule 13G, and for the completeness and accuracy of the information concerning such person contained therein; but none of them is responsible for the completeness or accuracy of the information concer

February 14, 2024 SC 13G/A

XFOR / X4 Pharmaceuticals, Inc. / Lincoln Park Capital Fund, LLC - SCHEDULE 13G/A Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G/A Under the Securities Exchange Act of 1934 (Amendment No. 1)* X4 PHARMACEUTICALS, INC. (Name of Issuer) COMMON STOCK, PAR VALUE $0.001 PER SHARE (Title of Class of Securities) 98420X103 (CUSIP Number) December 31, 2023 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate

February 14, 2024 SC 13G/A

XFOR / X4 Pharmaceuticals, Inc. / ORBIMED ADVISORS LLC - AMENDMENT NO. 4 Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No.

February 14, 2024 EX-99.A

JOINT FILING AGREEMENT

EXHIBIT A JOINT FILING AGREEMENT The undersigned hereby agree that this Amendment No.

February 13, 2024 EX-99.A

AGREEMENT REGARDING THE JOINT FILING OF SCHEDULE 13G

EX-99.A Exhibit A AGREEMENT REGARDING THE JOINT FILING OF SCHEDULE 13G The undersigned hereby agree as follows: i. Each of them is individually eligible to use the Schedule 13G to which this Exhibit is attached, and such Schedule 13G is filed on behalf of each of them; and ii. Each of them is responsible for the timely filing of such Schedule 13G and any amendments thereto, and for the completenes

February 13, 2024 SC 13G/A

XFOR / X4 Pharmaceuticals, Inc. / Bain Capital Life Sciences Fund, L.P. - SC 13G/A Passive Investment

SC 13G/A UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 SCHEDULE 13G (Rule 13d-102) Information to be Included in Statements Filed Pursuant to § 240.

January 25, 2024 S-8

As filed with the Securities and Exchange Commission on January 25, 2024

As filed with the Securities and Exchange Commission on January 25, 2024 Registration No.

January 25, 2024 EX-FILING FEES

Filing Fee Table

Exhibit 107 Calculation of Filing Fee Table Form S-8 (Form Type) X4 Pharmaceuticals, Inc.

January 16, 2024 SC 13G/A

XFOR / X4 Pharmaceuticals, Inc. / MILLENNIUM MANAGEMENT LLC Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (AMENDMENT NO. 1) X4 PHARMACEUTICALS, INC. (Name of Issuer) COMMON STOCK, PAR VALUE $0.001 PER SHARE (Title of Class of Securities) 98420X103 (CUSIP Number) DECEMBER 31, 2023 (Date of event which requires filing of this statement) Check the appropriate box to designate the

January 8, 2024 8-K

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): January 8, 2024 X4 PHARMACEUTICAL

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): January 8, 2024 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commissio

January 8, 2024 SC 13G/A

XFOR / X4 Pharmaceuticals, Inc. / Empery Asset Management, LP - X4 PHARMACEUTICALS, INC. Passive Investment

SC 13G/A 1 p24-0029sc13ga.htm X4 PHARMACEUTICALS, INC. SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 1)* X4 Pharmaceuticals, Inc. (Name of Issuer) Common Stock, par value $0.001 (Title of Class of Securities) 98420X103 (CUSIP Number) December 31, 2023 (Date of event which requires filing of this statement) Check the

November 27, 2023 8-K

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): November 27, 2023 X4 PHARMACEUTIC

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): November 27, 2023 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commiss

November 14, 2023 8-K

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): November 13, 2023 X4 PHARMACEUTIC

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): November 13, 2023 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commiss

November 9, 2023 EX-99.1

X4 Pharmaceuticals Reports Third-Quarter 2023 Financial Results and Provides Corporate Updates U.S. New Drug Application for mavorixafor in WHIM syndrome accepted for Priority Review, establishing a PDUFA target action date of April 30, 2024; X4 elig

Exhibit 99.1 X4 Pharmaceuticals Reports Third-Quarter 2023 Financial Results and Provides Corporate Updates U.S. New Drug Application for mavorixafor in WHIM syndrome accepted for Priority Review, establishing a PDUFA target action date of April 30, 2024; X4 eligible to receive Priority Review Voucher if approved Presentations of additional data from ongoing Phase 2 clinical trial of mavorixafor i

November 9, 2023 EX-10.1

First Amendment to Second Amended and Restated Loan and Security Agreement, dated as of August 2, 2023, by and among X4 Pharmaceuticals, Inc., X4 Therapeutics, Inc, Hercules Capital, Inc. and Hercules Capital Funding IV LLC and Hercules Capital Funding Trust 2022-1.

Exhibit 10.1 Certain schedules and exhibits have been omitted from this Exhibit pursuant to Item 601(a)(5) of Regulation S-K. X4 Pharmaceuticals, Inc. will furnish a copy of any omitted schedule or exhibit to the U.S. Securities and Exchange Commission or its staff upon request. FIRST AMENDMENT TO SECOND AMENDED AND RESTATED LOAN AND SECURITY AGREEMENT THIS FIRST AMENDMENT TO SECOND AMENDED AND RE

November 9, 2023 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2023 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-38295 X4 PH

November 9, 2023 8-K

Financial Statements and Exhibits, Results of Operations and Financial Condition

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): November 9, 2023 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commissi

October 31, 2023 EX-99.1

X4 Pharmaceuticals Announces FDA Acceptance with Priority Review of U.S. NDA for Mavorixafor in WHIM Syndrome FDA sets a Prescription Drug User Fee Act (PDUFA) target action date of April 30, 2024 If the NDA is approved, company eligible to receive a

Exhibit 99.1 X4 Pharmaceuticals Announces FDA Acceptance with Priority Review of U.S. NDA for Mavorixafor in WHIM Syndrome FDA sets a Prescription Drug User Fee Act (PDUFA) target action date of April 30, 2024 If the NDA is approved, company eligible to receive a Priority Review Voucher (PRV) resulting from mavorixafor’s rare pediatric designation in WHIM syndrome NDA supported by positive results

October 31, 2023 8-K

Financial Statements and Exhibits, Other Events

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): October 31, 2023 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commissi

October 18, 2023 EX-99.1

X4 Pharmaceuticals Announces Appointment of Industry Veteran R. Keith Woods to Board of Directors

Exhibit 99.1 X4 Pharmaceuticals Announces Appointment of Industry Veteran R. Keith Woods to Board of Directors BOSTON, October 18, 2023 – X4 Pharmaceuticals (Nasdaq: XFOR), a company driven to improve the lives of people with rare diseases of the immune system, today announced the appointment of R. Keith Woods as an independent director to the company’s Board of Directors. “We are thrilled to welc

October 18, 2023 8-K

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): October 16, 2023 X4 PHARMACEUTICA

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): October 16, 2023 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commissi

September 5, 2023 EX-99.1

X4 Pharmaceuticals Announces Submission of New Drug Application (NDA) to U.S. FDA for Mavorixafor in WHIM Syndrome Submission supported by positive results from global, pivotal 4WHIM Phase 3 clinical trial

Exhibit 99.1 X4 Pharmaceuticals Announces Submission of New Drug Application (NDA) to U.S. FDA for Mavorixafor in WHIM Syndrome Submission supported by positive results from global, pivotal 4WHIM Phase 3 clinical trial BOSTON, September 5, 2023 – X4 Pharmaceuticals (Nasdaq: XFOR), a company driven to improve the lives of people with rare diseases of the immune system, today announced the submissio

September 5, 2023 8-K

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): September 5, 2023 X4 PHARMACEUTIC

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): September 5, 2023 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commiss

August 22, 2023 CORRESP

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

X4 Pharmaceuticals, Inc. 61 North Beacon Street, 4th Floor Boston, MA 02134 August 22, 2023 Via Edgar United States Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.E. Washington, D.C. 20549 Attn: Doris Stacey Gama RE: X4 Pharmaceuticals, Inc. Registration Statement on Form S-3 File No. 333-273961 Acceleration Request Requested Date: August 24, 2023 Requested Time

August 14, 2023 S-8

As filed with the Securities and Exchange Commission on August 11, 2023

As filed with the Securities and Exchange Commission on August 11, 2023 Registration No.

August 14, 2023 EX-FILING FEES

Filing Fee Table

Exhibit 107 Calculation of Filing Fee Table Form S-8 (Form Type) X4 Pharmaceuticals, Inc.

August 14, 2023 EX-99.2

Amended and Restated 2019 Inducement Equity Incentive Plan

Exhibit 99.2 X4 Pharmaceuticals, Inc. AMENDED AND RESTATED 2019 INDUCEMENT EQUITY INCENTIVE PLAN (Adopted June 17, 2019, as Amended June 13, 2023) 1. Purpose The purpose of this 2019 Inducement Equity Incentive Plan (the “Plan”) of X4 Pharmaceuticals, Inc., a Delaware corporation (the “Company”), is to advance the interests of the Company’s stockholders by enhancing the Company’s ability to attrac

August 14, 2023 EX-FILING FEES

Filing Fee Table

Exhibit 107 Calculation of Filing Fee Tables Form S-3 (Form Type) X4 Pharmaceuticals, Inc.

August 14, 2023 S-3

As filed with the Securities and Exchange Commission on August 11, 2023

As filed with the Securities and Exchange Commission on August 11, 2023 Registration No.

August 14, 2023 EX-99.1

Amended and Restated 2017 Employee Stock Purchase Plan

Exhibit 99.1 X4 PHARMACEUTICALS, INC. AMENDED AND RESTATED 2017 EMPLOYEE STOCK PURCHASE PLAN The purpose of this Amended and Restated 2017 Employee Stock Purchase Plan (this “Plan”) is to provide eligible employees of X4 Pharmaceuticals, Inc. (the “Company”) and certain of its subsidiaries with opportunities to purchase shares of the Company’s common stock, $0.001 par value per share (the “Common

August 10, 2023 EX-10.3

Inducement Equity Incentive Plan

Exhibit 10.3 X4 Pharmaceuticals, Inc. AMENDED AND RESTATED 2019 INDUCEMENT EQUITY INCENTIVE PLAN (Adopted June 17, 2019, as Amended June 13, 2023) 1. Purpose The purpose of this 2019 Inducement Equity Incentive Plan (the “Plan”) of X4 Pharmaceuticals, Inc., a Delaware corporation (the “Company”), is to advance the interests of the Company’s stockholders by enhancing the Company’s ability to attrac

August 10, 2023 EX-99.1

X4 Pharmaceuticals Reports Second-Quarter 2023 Financial Results, Provides Corporate Updates, and Reports Emerging Data from Chronic Neutropenia Clinical Program Submission of first U.S. New Drug Application for mavorixafor in WHIM syndrome on track

Exhibit 99.1 X4 Pharmaceuticals Reports Second-Quarter 2023 Financial Results, Provides Corporate Updates, and Reports Emerging Data from Chronic Neutropenia Clinical Program Submission of first U.S. New Drug Application for mavorixafor in WHIM syndrome on track for early 2H 2023 Emerging data from ongoing Phase 2 trial in certain chronic neutropenic disorders show mavorixafor durably increased ne

August 10, 2023 EX-10.4

X4 Pharmaceuticals Inc. Amended and Restated

Exhibit 10.4 X4 PHARMACEUTICALS, INC. AMENDED AND RESTATED 2017 EMPLOYEE STOCK PURCHASE PLAN The purpose of this Amended and Restated 2017 Employee Stock Purchase Plan (this “Plan”) is to provide eligible employees of X4 Pharmaceuticals, Inc. (the “Company”) and certain of its subsidiaries with opportunities to purchase shares of the Company’s common stock, $0.001 par value per share (the “Common

August 10, 2023 8-K

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): August 10, 2023 X4 PHARMACEUTICAL

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): August 10, 2023 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commissio

August 10, 2023 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2023 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-38295 X4 PHARMAC

August 3, 2023 EX-99.1

X4 Pharmaceuticals Closes $115 Million Loan Facility with Hercules Capital

Exhibit 99.1 X4 Pharmaceuticals Closes $115 Million Loan Facility with Hercules Capital BOSTON, August 3, 2023 – X4 Pharmaceuticals (Nasdaq: XFOR), a leader in the discovery and development of novel small-molecule therapeutics to benefit people with rare diseases of the immune system, today announced the closing of a $115 million loan facility with Hercules Capital, Inc. (NYSE: HTGC) (“Hercules”).

August 3, 2023 8-K

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): August 2, 2023 X4 PHARMACEUTICALS

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): August 2, 2023 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission

June 21, 2023 424B3

42,784,203 Shares of Common Stock Offered by the Selling Stockholders

424B3 Table of Contents As Filed Pursuant to Rule 424(b)(3) Registration No. 333-272551 PROSPECTUS 42,784,203 Shares of Common Stock Offered by the Selling Stockholders This prospectus relates to the resale from time to time of up to 42,784,203 shares of common stock, par value $0.001 per share, of X4 Pharmaceuticals, Inc. (the “Common Stock”) by the selling stockholders listed on page 10 (the “Se

June 16, 2023 CORRESP

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

X4 Pharmaceuticals, Inc. 61 North Beacon Street, 4th Floor Boston, MA 02134 June 16, 2023 Via Edgar United States Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.E. Washington, D.C. 20549 Attn: Jimmy McNamara RE: X4 Pharmaceuticals, Inc. Registration Statement on Form S-3 File No. 333-272551 Acceleration Request Requested Date: June 20, 2023 Requested Time: 4:00

June 16, 2023 SC 13G

XFOR / X4 Pharmaceuticals Inc / MILLENNIUM MANAGEMENT LLC Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 X4 PHARMACEUTICALS, INC. (Name of Issuer) COMMON STOCK, PAR VALUE $0.001 PER SHARE (Title of Class of Securities) 98420X103 (CUSIP Number) JUNE 9, 2023 (Date of event which requires filing of this statement) Check the appropriate box to designate the rule pursuant to which

June 15, 2023 8-K

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): June 13, 2023 X4 PHARMACEUTICALS,

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): June 13, 2023 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission

June 9, 2023 S-3

As filed with the Securities and Exchange Commission on June 9, 2023

As filed with the Securities and Exchange Commission on June 9, 2023 Registration No.

June 9, 2023 EX-FILING FEES

Filing Fee Table.

Exhibit 107 Calculation of Filing Fee Tables Form S-3 (Form Type) X4 Pharmaceuticals, Inc.

June 1, 2023 8-K

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): June 1, 2023 X4 PHARMACEUTICALS,

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): June 1, 2023 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission F

May 26, 2023 SC 13D/A

XFOR / X4 Pharmaceuticals Inc / Growth Equity Opportunities 18 VGE, LLC - GROWTH EQUITY OPPORTUNITIES 18 VGE, LLC / X4 PHARMACEUTICALS, INC. -- SCHEDULE 13D/A(#2) Activist Investment

Schedule 13D UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 2)* X4 Pharmaceuticals, Inc. (Name of Issuer) Common Stock, $0.001 par value (Title of Class of Securities) 98420X103 (CUSIP Number) Louis S. Citron, Esq. New Enterprise Associates 1954 Greenspring Drive, Suite 600, Timonium, MD 21093 (410) 842-

May 16, 2023 EX-10.1

Securities Purchase Agreement, dated May 15, 2023, by and among X4 Pharmaceuticals, Inc. and the persons party thereto.

Exhibit 10.1 SECURITIES PURCHASE AGREEMENT This SECURITIES PURCHASE AGREEMENT (this “Agreement”) is made and entered into as of May 15, 2023, by and among X4 Pharmaceuticals, Inc., a Delaware corporation (the “Company”), and the Investors identified on Exhibit A attached hereto (each an “Investor” and collectively the “Investors”). RECITALS A. The Company and the Investors are executing and delive

May 16, 2023 8-K

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): May 15, 2023 X4 PHARMACEUTICALS,

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): May 15, 2023 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission F

May 16, 2023 EX-99.1

X4 Pharmaceuticals Announces $65 Million Private Placement Priced At-the-Market X4 WHIM Phase 3 clinical data webinar to be held today at 4 pm ET

Exhibit 99.1 X4 Pharmaceuticals Announces $65 Million Private Placement Priced At-the-Market X4 WHIM Phase 3 clinical data webinar to be held today at 4 pm ET BOSTON, Mass., May 16, 2023 – X4 Pharmaceuticals, Inc. (Nasdaq: XFOR), a leader in the discovery and development of novel small molecule therapeutics to benefit people with rare diseases of the immune system, today announced that it has agre

May 16, 2023 EX-10.2

Registration Rights Agreement, dated May 15, 2023, by and among X4 Pharmaceuticals, Inc. and the persons party thereto.

Exhibit 10.2 REGISTRATION RIGHTS AGREEMENT This REGISTRATION RIGHTS AGREEMENT (this “Agreement”) is made and entered into as of May 15, 2023, by and among X4 Pharmaceuticals, Inc., a Delaware corporation (the “Company”), and the “Investors” named in that certain Securities Purchase Agreement by and among the Company and the Investors, dated as of May 15 2023 (the “Purchase Agreement”). Capitalized

May 16, 2023 EX-99.3

A Deeper Dive into Mavorixafor Phase 3 Data and Unmet Patient Needs in WHIM Syndrome May 16, 2023 PROGRESS PATIENTS 2 Forward-Looking Statements This presentation contains forward-looking statements within the meaning of the Private Securities Litiga

x44whimdataeventdeckfina A Deeper Dive into Mavorixafor Phase 3 Data and Unmet Patient Needs in WHIM Syndrome May 16, 2023 PROGRESS PATIENTS 2 Forward-Looking Statements This presentation contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended.

May 16, 2023 EX-99.2

X4 Pharmaceuticals Announces Positive Phase 3 Results Showing Mavorixafor Reduced the Rate, Severity, and Duration of Infections vs. Placebo in Participants Diagnosed with WHIM Syndrome ~60% reduction in annualized infection rate seen in the mavorixa

Exhibit 99.2 X4 Pharmaceuticals Announces Positive Phase 3 Results Showing Mavorixafor Reduced the Rate, Severity, and Duration of Infections vs. Placebo in Participants Diagnosed with WHIM Syndrome ~60% reduction in annualized infection rate seen in the mavorixafor arm vs. placebo (p<0.01) >75% reduction in the percentage of individuals experiencing severe infections (Grade 3 or higher) in the ma

May 16, 2023 EX-4.1

Form of May 2023 Pre-Funded Warrant.

EXHIBIT 4.1 FORM THESE SECURITIES REPRESENTED HEREBY AND THE SECURITIES ISSUABLE UPON EXERCISE OF THESE SECURITIES HAVE NOT BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE BUT HAVE BEEN OR WILL BE ISSUED IN RELIANCE UPON AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED, AND, ACCORDINGLY, MAY NOT BE TRANSFERRED UNLESS

May 4, 2023 EX-99.1

X4 Pharmaceuticals Reports First-Quarter 2023 Financial Results and Provides Corporate Update Company to host webinar event on May 16th presenting new clinical data from the 4WHIM Phase 3 trial; oral presentation to follow on May 21st at the 2023 Cli

Exhibit 99.1 X4 Pharmaceuticals Reports First-Quarter 2023 Financial Results and Provides Corporate Update Company to host webinar event on May 16th presenting new clinical data from the 4WHIM Phase 3 trial; oral presentation to follow on May 21st at the 2023 Clinical Immunology Society (CIS) Annual Meeting U.S. NDA submission of mavorixafor for WHIM syndrome on track for early 2H 2023 Presentatio

May 4, 2023 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2023 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-38295 X4 PHARMA

May 4, 2023 8-K

Financial Statements and Exhibits, Results of Operations and Financial Condition

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): May 4, 2023 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission Fi

May 4, 2023 8-K

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): May 4, 2023 X4 PHARMACEUTICALS, I

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): May 4, 2023 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission Fi

May 4, 2023 EX-99.1

X4 Pharmaceuticals Reports First-Quarter 2023 Financial Results and Provides Corporate Update Company to host webinar event on May 16th presenting new clinical data from the 4WHIM Phase 3 trial; oral presentation to follow on May 21st at the 2023 Cli

Exhibit 99.1 X4 Pharmaceuticals Reports First-Quarter 2023 Financial Results and Provides Corporate Update Company to host webinar event on May 16th presenting new clinical data from the 4WHIM Phase 3 trial; oral presentation to follow on May 21st at the 2023 Clinical Immunology Society (CIS) Annual Meeting U.S. NDA submission of mavorixafor for WHIM syndrome on track for early 2H 2023 Presentatio

May 4, 2023 8-K

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): May 4, 2023 X4 PHARMACEUTICALS, I

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): May 4, 2023 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission Fi

April 27, 2023 DEFA14A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. 1)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. 1) Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Defi

April 25, 2023 DEFA14A

SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.)

SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.

April 25, 2023 DEF 14A

SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.

March 21, 2023 8-K

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 21, 2023 X4 PHARMACEUTICALS

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 21, 2023 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission

March 21, 2023 EX-10.27

Second Amended and Restated Loan and Security Agreement, dated as of January 6, 2023, by and among X4 Pharmaceuticals, Inc., X4 Therapeutics, Inc., Hercules Capital, Inc. and Hercules Capital Funding IV LLC and Hercules Capital Funding Trust 2022-1

x41027 Exhibit 10.27 Certain schedules and exhibits have been omitted from this Exhibit pursuant to Item 601(a)(5) of Regulation S-K. X4 Pharmaceuticals, Inc. will furnish a copy of any omitted schedule or exhibit to the U.S. Securities and Exchange Commission or its staff upon request. SECOND AMENDED AND RESTATED LOAN AND SECURITY AGREEMENT THIS SECOND AMENDED AND RESTATED LOAN AND SECURITY AGREE

March 21, 2023 EX-10.,16

Director Compensation Policy

Exhibit 10.16 X4 PHARMACEUTICALS, INC. DIRECTOR COMPENSATION POLICY (Last modified: March 2, 2023) 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. Director Compensation Our goal

March 21, 2023 EX-99.1

X4 Pharmaceuticals Reports Fourth Quarter and Full-Year 2022 Financial Results and Provides Corporate Update Upcoming expected milestones for investigational therapy mavorixafor in WHIM syndrome include: presentation of additional Phase 3 clinical da

Exhibit 99.1 X4 Pharmaceuticals Reports Fourth Quarter and Full-Year 2022 Financial Results and Provides Corporate Update Upcoming expected milestones for investigational therapy mavorixafor in WHIM syndrome include: presentation of additional Phase 3 clinical data in 2Q 2023, NDA submission in early 2H 2023, and potential U.S. launch in 1H 2024 Announcement of data from ongoing chronic neutropeni

March 21, 2023 EX-4.17

Description of Registered Securities

Exhibit 4.17 DESCRIPTION OF SECURITIES REGISTERED UNDER SECTION 12 OF THE SECURITIES EXCHANGE ACT OF 1934 The following description of our common stock and provisions of our restated certificate of incorporation, as amended (“restated certificate”), and amended and restated by-laws (“by-laws”) are summaries, and does not purport to be complete and is subject to, and is qualified in its entirety by

March 21, 2023 8-K

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 21, 2023 X4 PHARMACEUTICALS

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 21, 2023 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission

March 21, 2023 EX-10.21

Executive Employment Agreement, dated as of November 14, 2022, by and between the Company and Murray Stewart

Exhibit 10.21 EXECUTIVE EMPLOYMENT AGREEMENT THIS EXECUTIVE EMPLOYMENT AGREEMENT (this “Agreement”) is entered into as of November 14, 2022, (the “Effective Date”), by and between X4 Pharmaceuticals, Inc. (the “Company”), and Murray Stewart (“Executive”) (collectively referred to as the “Parties” or individually referred to as a “Party”). R E C I T A L S WHEREAS, the Company desires to employ Exec

March 21, 2023 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) x ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2022 or o ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-38295 X4 PHARMACEUTICALS

March 10, 2023 8-K

Other Events

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 10, 2023 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission

February 14, 2023 SC 13G/A

XFOR / X4 Pharmaceuticals Inc / Point72 Asset Management, L.P. - SCHEDULE 13G/A, AMENDMENT #2 Passive Investment

SC 13G/A 1 pt7213ga.htm SCHEDULE 13G/A, AMENDMENT #2 240.13d-102 Schedule 13G - Information to be included in statements filed pursuant to 240.13d-1(b), (c), and (d) and amendments thereto filed pursuant to 240.13d-2. Securities and Exchange Commission, Washington, D.C. 20549 Schedule 13G Under the Securities Exchange Act of 1934 (Amendment No. 2)* (Name of Issuer) X4 Pharmaceuticals, Inc. (Title

February 14, 2023 SC 13G/A

XFOR / X4 Pharmaceuticals Inc / BIOTECHNOLOGY VALUE FUND L P - AMENDMENT NO. 4 TO THE SCHEDULE 13G Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G (Rule 13d-102) INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULES 13d-1(b), (c), AND (d) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(b) (Amendment No. 4)1 X4 Pharmaceuticals, Inc. (Name of Issuer) Common Stock, par value $0.001 per share (Title of Class of Securities) 98420X103 (CUSIP Number)

February 14, 2023 SC 13G/A

XFOR / X4 Pharmaceuticals Inc / Ikarian Capital, LLC - SC 13G/A Passive Investment

SC 13G/A 1 d430008dsc13ga.htm SC 13G/A UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 3)* X4 PHARMACEUTICALS, INC. (Name of Issuer) Common Stock (Title of Class of Securities) 98420X103 (CUSIP Number) December 31, 2022 (Date of Event which Requires Filing of this Statement) Check the appropriate box to d

February 14, 2023 SC 13G/A

XFOR / X4 Pharmaceuticals Inc / ORBIMED ADVISORS LLC - AMENDMENT NO. 3 Passive Investment

SC 13G/A 1 ss1758642sc13ga.htm AMENDMENT NO. 3 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 SCHEDULE 13G (Amendment No. 3)* Under the Securities Exchange Act of 1934 X4 PHARMACEUTICALS, INC. (Name of Issuer) Common Stock, par value $0.001 per share (Title of Class of Securities) 98420X103 (CUSIP Number) December 31, 2022 (Date of Event Which Requires Filing of this Stateme

February 14, 2023 SC 13G/A

XFOR / X4 Pharmaceuticals Inc / Bain Capital Life Sciences Fund, L.P. - SC 13G/A Passive Investment

SC 13G/A 1 d398382dsc13ga.htm SC 13G/A UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 SCHEDULE 13G (Rule 13d-102) Information to be Included in Statements Filed Pursuant to § 240.13d-1(b), (c) and (d) and Amendments Thereto Filed Pursuant to § 240.13d-2 Under the Securities Exchange Act of 1934 (Amendment No. 2) X4 Pharmaceuticals, Inc. (Name of Issuer) Common Stock, $0.001

February 14, 2023 EX-99.A

AGREEMENT REGARDING THE JOINT FILING OF SCHEDULE 13G

EX-99.A 2 d398382dex99a.htm EX-99.A Exhibit A AGREEMENT REGARDING THE JOINT FILING OF SCHEDULE 13G The undersigned hereby agree as follows: (i) Each of them is individually eligible to use the Schedule 13G to which this Exhibit is attached, and such Schedule 13G is filed on behalf of each of them; and (ii) Each of them is responsible for the timely filing of such Schedule 13G and any amendments th

February 14, 2023 EX-99.1

JOINT FILING AGREEMENT February 14, 2023

EX-99.1 2 d430008dex991.htm EX-99.1 EXHIBIT 99.1 JOINT FILING AGREEMENT February 14, 2023 Pursuant to and in accordance with the Securities Exchange Act of 1934, as amended (the “Act”), and the rules and regulations thereunder, each party hereto hereby agrees to the joint filing, on behalf of each of them, of any filing required by such party under Section 13 or Section 16 of the Act or any rule o

February 14, 2023 EX-99.A

JOINT FILING AGREEMENT

EX-99.A 2 ss1758642ex99a.htm JOINT FILING AGREEMENT EXHIBIT A JOINT FILING AGREEMENT The undersigned hereby agree that this amendment to Schedule 13G dated December 31, 2022 (the “Schedule 13G”), with respect to the Common Stock, par value $0.001 per share, of X4 Pharmaceuticals, Inc. is filed on behalf of each of us pursuant to and in accordance with the provisions of Rule 13d-1(k) under the Secu

January 20, 2023 S-8

As filed with the Securities and Exchange Commission on January 20, 2023

As filed with the Securities and Exchange Commission on January 20, 2023 Registration No.

January 20, 2023 EX-FILING FEES

Filing Fee Table

EX-FILING FEES 2 ex107calculationoffilingfe.htm EX-FILING FEES Exhibit 107 Calculation of Filing Fee Table Form S-8 (Form Type) X4 Pharmaceuticals, Inc. (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered Security Type Security Class Title Fee Calculation Rule Amount to be Registered (1) Proposed Maximum Offering Price Per Unit Maximum Aggregate Offering Price Fee Rate

January 13, 2023 SC 13G

XFOR / X4 Pharmaceuticals Inc / Empery Asset Management, LP - X4 PHARMACEUTICALS, INC. Passive Investment

SC 13G 1 p23-0098sc13g.htm X4 PHARMACEUTICALS, INC. SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. )* X4 Pharmaceuticals, Inc. (Name of Issuer) Common Stock, par value $0.001 (Title of Class of Securities) 98420X103 (CUSIP Number) December 31, 2022 (Date of event which requires filing of this statement) Check the appr

January 6, 2023 8-K

Entry into a Material Definitive Agreement, Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant

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): January 6, 2023 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commissio

January 5, 2023 8-K

Regulation FD Disclosure

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): January 5, 2023 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commissio

December 23, 2022 8-K

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): December 20, 2022 X4 PHARMACEUTIC

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): December 20, 2022 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commiss

December 23, 2022 EX-10.1

X4 Pharmaceuticals Inc. 2019 Inducement Equity Incentive Plan

Exhibit 10.1 X4 Pharmaceuticals, Inc. AMENDED AND RESTATED 2019 INDUCEMENT EQUITY INCENTIVE PLAN (Adopted June 17, 2019, as Amended December 20, 2022) 1. Purpose The purpose of this 2019 Inducement Equity Incentive Plan (the ?Plan?) of X4 Pharmaceuticals, Inc., a Delaware corporation (the ?Company?), is to advance the interests of the Company?s stockholders by enhancing the Company?s ability to at

December 20, 2022 SC 13D/A

XFOR / X4 Pharmaceuticals Inc / Growth Equity Opportunities 18 VGE, LLC - GROWTH EQUITY OPPORTUNITIES 18 VGE, LLC / X4 PHARMACEUTICALS, INC. -- SCHEDULE 13D/A(#1) Activist Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 1)* X4 Pharmaceuticals, Inc. (Name of Issuer) Common Stock, $0.001 par value (Title of Class of Securities) 98420X103 (CUSIP Number) Louis S. Citron, Esq. New Enterprise Associates 1954 Greenspring Drive, Suite 600, Timonium, MD 21093 (410) 842-4000 (Name, A

December 9, 2022 424B5

52,300,000 Shares of Common Stock Pre-Funded Warrants to Purchase 6,800,000 Shares of Common Stock Class C Warrants to Purchase 29,550,000 Shares of Common Stock (or Pre-Funded Warrants)

424B5 1 d421217d424b5.htm 424B5 Table of Contents Filed Pursuant to Rule 424(b)(5) Registration No. 333-249544 PROSPECTUS SUPPLEMENT (To Prospectus dated October 26, 2020) 52,300,000 Shares of Common Stock Pre-Funded Warrants to Purchase 6,800,000 Shares of Common Stock Class C Warrants to Purchase 29,550,000 Shares of Common Stock (or Pre-Funded Warrants) We are offering (i) 59,100,000 shares of

December 9, 2022 EX-99.1

X4 Pharmaceuticals Announces Proposed Public Offering

Exhibit 99.1 X4 Pharmaceuticals Announces Proposed Public Offering BOSTON, Dec. 06, 2022 (GLOBAL NEWS WIRE)– X4 Pharmaceuticals, Inc. (Nasdaq: XFOR), a leader in the discovery and development of novel small-molecule therapeutics to benefit people with diseases of the immune system, announced today that it has commenced an underwritten public offering of shares of its common stock (or pre-funded wa

December 9, 2022 EX-1.1

Underwriting Agreement, dated December 7, 2022, by and among the Company, Piper Sandler & Co., Stifel, Nicolaus & Company, Incorporated, and Cantor Fitzgerald & Co.

Exhibit 1.1 X4 PHARMACEUTICALS, INC. 52,300,000 Shares of Common Stock Pre-Funded Warrants to Purchase 6,800,000 Shares of Common Stock Class C Warrants to Purchase 29,550,000 Shares of Common Stock UNDERWRITING AGREEMENT December 7, 2022 Piper Sandler & Co. Stifel, Nicolaus & Company, Incorporated Cantor Fitzgerald & Co. As Representatives of the several Underwriters c/o Piper Sandler & Co. 800 N

December 9, 2022 EX-4.1

Form of December 2022 Pre-Funded Warrant

Exhibit 4.1 FORM X4 PHARMACEUTICALS, INC. PRE-FUNDED WARRANT TO PURCHASE COMMON STOCK Number of Shares: [] (subject to adjustment) Warrant No.: PF- 2022-[] Original Issue Date: December 9, 2022 X4 Pharmaceuticals, Inc., a Delaware corporation (the “Company”), hereby certifies that, for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, [] or its register

December 9, 2022 8-K

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): December 6, 2022 X4 PHARMACEUTICA

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): December 6, 2022 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commissi

December 9, 2022 EX-4.2

Form of Class C Warrant.

Exhibit 4.2 X4 PHARMACEUTICALS, INC. CLASS C WARRANT TO PURCHASE COMMON STOCK Warrant No.: Warrant Shares: Initial Exercise Date: December 9, 2022 THIS CLASS C WARRANT TO PURCHASE COMMON STOCK (this “Warrant”) certifies that, for value received, or its assigns (the “Holder”) is entitled, upon the terms and subject to the limitations on exercise and the conditions hereinafter set forth, at any time

December 9, 2022 EX-99.2

X4 Pharmaceuticals Prices $65.0 Million Public Offering

EXHIBIT 99.2 X4 Pharmaceuticals Prices $65.0 Million Public Offering BOSTON, Dec. 07, 2022 (GLOBAL NEWS WIRE) – X4 Pharmaceuticals, Inc. (Nasdaq: XFOR), a leader in the discovery and development of novel small-molecule therapeutics to benefit people with diseases of the immune system, announced today the pricing of its previously announced underwritten public offering of 52,300,000 shares of its c

December 7, 2022 424B5

SUBJECT TO COMPLETION, DATED DECEMBER 6, 2022 PRELIMINARY PROSPECTUS SUPPLEMENT (To Prospectus dated October 26, 2020) Shares of Common Stock Pre-Funded Warrants to Purchase Shares of Common Stock Class C Warrants to Purchase Shares of Common Stock (

424B5 Table of Contents Filed Pursuant to Rule 424(b)(5) Registration No. 333-249544 The information in this preliminary prospectus supplement is not complete and may be changed. A registration statement relating to these securities has been declared effective by the Securities and Exchange Commission. This preliminary prospectus supplement and the accompanying prospectus are not an offer to sell

November 29, 2022 8-K

Regulation FD Disclosure, Financial Statements and Exhibits, Other Events

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): November 29, 2022 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commiss

November 29, 2022 EX-99.1

X4 Pharmaceuticals Announces Positive Top-Line Results from 4WHIM Global, Pivotal Phase 3 Trial of Once-Daily, Oral Mavorixafor in WHIM Syndrome 4WHIM trial meets primary endpoint and first key secondary endpoint, with mavorixafor achieving statistic

Exhibit 99.1 X4 Pharmaceuticals Announces Positive Top-Line Results from 4WHIM Global, Pivotal Phase 3 Trial of Once-Daily, Oral Mavorixafor in WHIM Syndrome 4WHIM trial meets primary endpoint and first key secondary endpoint, with mavorixafor achieving statistically significant and clinically relevant longer times above threshold levels for both absolute neutrophil (P <0.0001) and absolute lympho

November 29, 2022 EX-99.2

Positive 4WHIM Phase 3 Top-Line Results Conference Call & Webcast November 29, 2022 EXHIBIT 99.2 2 Forward-Looking Statements This presentation contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of

Positive 4WHIM Phase 3 Top-Line Results Conference Call & Webcast November 29, 2022 EXHIBIT 99.

November 9, 2022 8-K

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

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 (Data of earliest event reported): November 7, 2022 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commissi

November 9, 2022 EX-10.1

Form of Stock Appreciation Right Agreement under the X4 Pharmaceuticals, Inc. Amended and Restated 2017 Equity Incentive Plan.

EXHIBIT 10.1 X4 PHARMACEUTICALS, INC. AMENDED AND RESTATED 2017 EQUITY INCENTIVE PLAN STOCK APPRECIATION RIGHT NOTICE OF GRANT X4 Pharmaceuticals, Inc. (the ?Company?) hereby grants the following stock appreciation rights (?SARs?) with respect to the number of shares of Company?s Common Stock set forth below pursuant to its Amended and Restated 2017 Equity Incentive Plan (the ?Plan?). This Award i

November 3, 2022 EX-99.1

X4 Pharmaceuticals Reports Third Quarter 2022 Financial Results and Provides Corporate Update Following positive mavorixafor Phase 1b data release in multiple chronic neutropenic disorders, X4 continues to look forward to top-line results from its pi

Exhibit 99.1 X4 Pharmaceuticals Reports Third Quarter 2022 Financial Results and Provides Corporate Update Following positive mavorixafor Phase 1b data release in multiple chronic neutropenic disorders, X4 continues to look forward to top-line results from its pivotal Phase 3 trial in WHIM syndrome in the fourth quarter of 2022 Conference call to be hosted today at 8:30 a.m. ET BOSTON – November 3

November 3, 2022 8-K

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 (Data of earliest event reported): November 3, 2022 X4 PHARMACEUTICA

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 (Data of earliest event reported): November 3, 2022 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commissi

November 3, 2022 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2022 or ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-38295 X4 PH

November 3, 2022 EX-99.2

X4 Pharmaceuticals Announces Appointment of Industry Veteran Mark Baldry as Chief Commercial Officer A seasoned leader in the launch of rare and specialty pharmaceuticals, Mr. Baldry is expected to join X4 on November 3, 2022

Exhibit 99.2 X4 Pharmaceuticals Announces Appointment of Industry Veteran Mark Baldry as Chief Commercial Officer A seasoned leader in the launch of rare and specialty pharmaceuticals, Mr. Baldry is expected to join X4 on November 3, 2022 BOSTON – October 26, 2022 - X4 Pharmaceuticals, Inc. (Nasdaq: XFOR), a leader in the discovery and development of novel small-molecule therapeutics to benefit pe

October 4, 2022 EX-99.1

1 Candidate Indication Preclinical Phase 1 Phase 2 Phase 3 Expected Milestones Target Patient Populations C H R O N IC N E U T R O P E N IC D IS O R D E R S (In -h ou se ) Mavorixafor WHIM Syndrome (Warts, Hypogammaglobulinemia, Infections and Myelok

1 Candidate Indication Preclinical Phase 1 Phase 2 Phase 3 Expected Milestones Target Patient Populations C H R O N IC N E U T R O P E N IC D IS O R D E R S (In -h ou se ) Mavorixafor WHIM Syndrome (Warts, Hypogammaglobulinemia, Infections and Myelokathexis) Top-line data 4Q 2022 NDA Submission early 2H 2023 >1,000 U.

October 4, 2022 8-K

Regulation FD Disclosure, Financial Statements and Exhibits, Other Events

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 (Data of earliest event reported): October 4, 2022 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commissio

September 27, 2022 EX-99.1

X4 Pharmaceuticals Announces New Positive Phase 1b Data Supporting Mavorixafor’s Broad Potential in Chronic Neutropenia (CN) 100% of study participants (n=25) achieved robust responses to oral mavorixafor 100% of neutropenic participants (n=14) achie

X4 Pharmaceuticals Announces New Positive Phase 1b Data Supporting Mavorixafor?s Broad Potential in Chronic Neutropenia (CN) 100% of study participants (n=25) achieved robust responses to oral mavorixafor 100% of neutropenic participants (n=14) achieved normalized neutrophil counts Robust responses achieved across all CN disorders studied (idiopathic, cyclic, congenital); estimated diagnosed patient population ~ 50,000 in the U.

September 27, 2022 EX-99.2

Chronic Neutropenia Mavorixafor Beyond WHIM Syndrome September 27, 2022 Exhibit 99.2 2 Forward-Looking Statements This presentation contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as ame

Chronic Neutropenia Mavorixafor Beyond WHIM Syndrome September 27, 2022 Exhibit 99.

September 27, 2022 8-K

Regulation FD Disclosure, Financial Statements and Exhibits, Other Events

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 (Data of earliest event reported): September 27, 2022 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commis

September 1, 2022 EX-3.1

Restated Certificate of Incorporation, as amended, as of September 1, 2022

1 Exhibit 3.1 RESTATED CERTIFICATE OF INCORPORATION OF X4 PHARMACEUTICALS, INC. (Composite document reflecting amendments through September 1, 2022) (originally incorporated on August 2, 2010) 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

September 1, 2022 8-K

Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year, Material Modification to Rights of Security Holders, Financial Statements and Exhibits, Submission of Matters to a Vote of Security Holders

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 (Data of earliest event reported): September 1, 2022 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commiss

August 11, 2022 DEF 14A

SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

Table of Contents SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.

August 5, 2022 EX-99.1

Corporate Overview August 2022 2 Forward-Looking Statements This presentation contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended. These statements may be identified by the words

Corporate Overview August 2022 2 Forward-Looking Statements This presentation contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended.

August 5, 2022 424B3

101,850,730 Shares Common Stock Offered by the Selling Stockholders

Table of Contents As Filed Pursuant to Rule 424(b)(3) Registration No. 333-266410 PROSPECTUS 101,850,730 Shares Common Stock Offered by the Selling Stockholders This prospectus relates to the resale from time to time of up to 101,850,730 shares of common stock, par value $0.001 per share, of X4 Pharmaceuticals, Inc. (the ?Common Stock?) by the selling stockholders listed on page 7 (the ?Selling St

August 5, 2022 8-K

Regulation FD Disclosure, Financial Statements and Exhibits

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 (Data of earliest event reported): August 5, 2022 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission

August 4, 2022 EX-99.1

X4 Pharmaceuticals Reports Second Quarter 2022 Financial Results and Provides Corporate Update Highlights notable upcoming milestones including data from Phase 1b trial in chronic neutropenia, expected in late September, and results from global, pivo

Exhibit 99.1 X4 Pharmaceuticals Reports Second Quarter 2022 Financial Results and Provides Corporate Update Highlights notable upcoming milestones including data from Phase 1b trial in chronic neutropenia, expected in late September, and results from global, pivotal Phase 3 trial in WHIM syndrome, expected in 4Q 2022 Announces additional positive data from Phase 1b trial in Waldenstr?m?s Macroglob

August 4, 2022 8-K

Financial Statements and Exhibits, Results of Operations and Financial Condition

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 (Data of earliest event reported): August 4, 2022 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission

August 4, 2022 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2022 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-38295 X4 PHARMAC

August 3, 2022 CORRESP

X4 PHARMACEUTICALS, INC. 61 North Beacon Street, 4th Floor Boston, MA 02134

X4 PHARMACEUTICALS, INC. 61 North Beacon Street, 4th Floor Boston, MA 02134 August 3, 2022 VIA EDGAR United States Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.E. Washington, D.C. 20549 Attn: Jason Drory RE: X4 Pharmaceuticals, Inc. Registration Statement on Form S-3 File No. 333-266410 Acceleration Request Requested Date: August 5, 2022 Requested Time: 4:00 p

August 1, 2022 PRE 14A

SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

Table of Contents SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.

July 29, 2022 EX-FILING FEES

Filing Fee Table.

Exhibit 107 Calculation of Filing Fee Tables Form S-3 (Form Type) X4 Pharmaceuticals, Inc.

July 29, 2022 424B3

1,666,666 Shares Common Stock Offered by the Selling Stockholder

As Filed Pursuant to Rule 424(b)(3) Registration No. 333-264459 PROSPECTUS 1,666,666 Shares Common Stock Offered by the Selling Stockholder This prospectus relates to the resale from time to time of up to 1,666,666 shares of common stock, par value $0.001 per share, of X4 Pharmaceuticals, Inc. (the ?Common Stock?) by the selling stockholder listed on page 7 (the ?Selling Stockholder?), including i

July 29, 2022 S-3

As filed with the Securities and Exchange Commission on July 29, 2022

Table of Contents As filed with the Securities and Exchange Commission on July 29, 2022 Registration No.

July 29, 2022 8-K

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

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 (Data of earliest event reported): July 25, 2022 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission

July 19, 2022 SC 13D

XFOR / X4 Pharmaceuticals Inc / Growth Equity Opportunities 18 VGE, LLC - GROWTH EQUITY OPPORTUNITIES 18 VGE, LLC / X4 PHARMACEUTICALS, INC. -- SCHEDULE 13D Activist Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. ???)* X4 Pharmaceuticals, Inc. (Name of Issuer) Common Stock, $0.001 par value (Title of Class of Securities) 98420X103 (CUSIP Number) Louis S. Citron, Esq. New Enterprise Associates 1954 Greenspring Drive, Suite 600, Timonium, MD 21093 (410) 842-4000 (Name,

July 1, 2022 EX-10.2

Registration Rights Agreement, dated June 30, 2022, by and among X4 Pharmaceuticals Inc. and the persons party thereto.

EXHIBIT 10.2 REGISTRATION RIGHTS AGREEMENT This REGISTRATION RIGHTS AGREEMENT (this ?Agreement?) is made and entered into as of June 30, 2022 by and among X4 Pharmaceuticals, Inc., a Delaware corporation (the ?Company?), and the ?Investors? named in that certain Securities Purchase Agreement by and among the Company and the Investors, dated as of June 30, 2022 (the ?Purchase Agreement?). Capitaliz

July 1, 2022 EX-4.1

Form of July 2022 Pre-Funded Warrant

EXHIBIT 4.1 FORM THESE SECURITIES REPRESENTED HEREBY AND THE SECURITIES ISSUABLE UPON EXERCISE OF THESE SECURITIES HAVE NOT BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE BUT HAVE BEEN OR WILL BE ISSUED IN RELIANCE UPON AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED, AND, ACCORDINGLY, MAY NOT BE TRANSFERRED UNLESS

July 1, 2022 EX-10.3

Amendment No. 4 to Amended and Restated Loan and Security Agreement, dated as of June 30, 2022, by and among X4 Pharmaceuticals, Inc., each of its Qualified Subsidiaries (including X4 Therapeutics, Inc.), the Lender, and Hercules Capital, Inc., as Agent.

EXHIBIT 10.3 AMENDMENT NO. 4 TO LOAN AND SECURITY AGREEMENT This Amendment No. 4 to Loan and Security Agreement (the ?Fourth Amendment?) is dated as of June 30, 2022 (the ?Fourth Amendment Date?) and is entered into by and among X4 PHARMACEUTICALS, INC., a Delaware corporation (the ?Company?), and each of its Qualified Subsidiaries, including without limitation X4 THERAPEUTICS, INC. (?Therapeutics

July 1, 2022 EX-10.1

Securities Purchase Agreement, dated June 30, 2022, by and among X4 Pharmaceuticals Inc. and the persons party thereto.

EXHIBIT 10.1 SECURITIES PURCHASE AGREEMENT This SECURITIES PURCHASE AGREEMENT (this ?Agreement?) is made and entered into as of June 30, 2022 by and among X4 Pharmaceuticals, Inc., a Delaware corporation (the ?Company?), and the Investors identified on Exhibit A attached hereto (each an ?Investor? and collectively the ?Investors?). RECITALS A. The Company and the Investors are executing and delive

July 1, 2022 EX-99.1

X4 Pharmaceuticals Announces $55 Million Private Placement Financing and Debt Facility Amendment Extending Interest-Only Period by up to 12 Months

Exhibit 99.1 X4 Pharmaceuticals Announces $55 Million Private Placement Financing and Debt Facility Amendment Extending Interest-Only Period by up to 12 Months BOSTON, Mass., June 30, 2022 ? X4 Pharmaceuticals, Inc. (Nasdaq: XFOR), a leader in the discovery and development of novel CXCR4-targeted small molecule therapeutics to benefit people with rare immune system disorders, today announced that

July 1, 2022 8-K

Entry into a Material Definitive Agreement, Unregistered Sales of Equity Securities, Financial Statements and Exhibits, Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant, Other Events

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 (Data of earliest event reported): June 30, 2022 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission

July 1, 2022 EX-4.2

Form of July 2022 Warrant

EXHIBIT 4.2 FORM THESE SECURITIES REPRESENTED HEREBY AND THE SECURITIES ISSUABLE UPON EXERCISE OF THESE SECURITIES HAVE NOT BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE BUT HAVE BEEN OR WILL BE ISSUED IN RELIANCE UPON AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED, AND, ACCORDINGLY, MAY NOT BE TRANSFERRED UNLESS

June 7, 2022 8-K

Submission of Matters to a Vote of Security Holders

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 (Data of earliest event reported): June 6, 2022 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission F

May 20, 2022 8-K

Regulation FD Disclosure, Other Events

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 (Data of earliest event reported): May 20, 2022 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission F

May 12, 2022 CORRESP

X4 PHARMACEUTICALS, INC. 61 North Beacon Street, 4th Floor Boston, MA 02134

X4 PHARMACEUTICALS, INC. 61 North Beacon Street, 4th Floor Boston, MA 02134 May 12, 2022 VIA EDGAR United States Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.E. Washington, D.C. 20549 Attn: Tyler Howes RE: X4 Pharmaceuticals, Inc. Registration Statement on Form S-3 File No. 333-264459 Acceleration Request Requested Date: May 13, 2022 Requested Time: 4:00 p.m.

May 12, 2022 8-K

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

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 (Data of earliest event reported): May 12, 2022 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission F

May 12, 2022 EX-99.1

X4 Pharmaceuticals Reports First Quarter 2022 Financial Results and Provides Corporate Update Top-line data from pivotal 4WHIM Phase 3 clinical trial in WHIM syndrome expected in 4Q22 Clinical and regulatory updates from ongoing chronic neutropenia P

Exhibit 99.1 X4 Pharmaceuticals Reports First Quarter 2022 Financial Results and Provides Corporate Update Top-line data from pivotal 4WHIM Phase 3 clinical trial in WHIM syndrome expected in 4Q22 Clinical and regulatory updates from ongoing chronic neutropenia Phase 1b study anticipated during 3Q 2022; Waldenstr?m?s macroglobulinemia Phase 1b study now fully enrolled with results expected in seco

May 12, 2022 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2022 or ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-38295 X4 PHARMA

April 25, 2022 DEF 14A

SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.

April 25, 2022 DEFA14A

SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.)

SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No.

April 22, 2022 S-3

As filed with the Securities and Exchange Commission on April 22, 2022

As filed with the Securities and Exchange Commission on April 22, 2022 Registration No.

April 22, 2022 EX-FILING FEES

Filing Fee Table

EX-FILING FEES 2 ex107.htm EX-FILING FEES Exhibit 107 Calculation of Filing Fee Tables Form S-3 (Form Type) X4 Pharmaceuticals, Inc. (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered Securities Security Type Security Class Title Fee Calculation Rule Amount Registered(1)(2) Proposed Maximum Offering Price Per Share(3) Maximum Aggregate Offering Price Fee Rate Amount o

March 22, 2022 424B5

Up to $23,300,000 Common Stock

PROSPECTUS SUPPLEMENT Filed Pursuant to Rule 424(b)(5) (To Prospectus dated August 19, 2020) Registration No.

March 17, 2022 8-K

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

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 (Data of earliest event reported): March 17, 2022 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission

March 17, 2022 EX-10.21

Amended and Restated Executive Employment Agreement, dated as of March 7, 2022 by and between the Company and Art Taveres

Exhibit 10.21 AMENDED AND RESTATED EXECUTIVE EMPLOYMENT AGREEMENT THIS AMENDED AND RESTATED EXECUTIVE EMPLOYMENT AGREEMENT (this ?Agreement?) is entered into as of March 7, 2022, (the ?Effective Date?) by and between X4 Pharmaceuticals, Inc. (the ?Company?), and Dr. Arthur Taveras (?Executive?) (collectively referred to as the ?Parties? or individually referred to as a ?Party?). R E C I T A L S WH

March 17, 2022 EX-99.1

X4 Pharmaceuticals Reports Fourth-Quarter and Full-Year 2021 Financial Results and Provides Corporate Update Top-line data from pivotal 4WHIM Phase 3 clinical trial in WHIM syndrome expected in 4Q22 Clinical and regulatory updates from ongoing chroni

Exhibit 99.1 X4 Pharmaceuticals Reports Fourth-Quarter and Full-Year 2021 Financial Results and Provides Corporate Update Top-line data from pivotal 4WHIM Phase 3 clinical trial in WHIM syndrome expected in 4Q22 Clinical and regulatory updates from ongoing chronic neutropenia Phase 1b trial anticipated during 2Q/3Q 2022 Additional Waldenstr?m?s Macroglobulinemia Phase 1b data expected in second ha

March 17, 2022 EX-21.1

List of Subsidiaries

Exhibit 21.1 Subsidiaries The following is the name, jurisdiction of organization and percentage ownership by the Company of its subsidiaries. Subsidiary Jurisdiction of Incorporation Company Owned by Percentage X4 Pharmaceuticals, Inc. Delaware 100% X4 Pharmaceuticals (Austria) GmbH Austria 100% X4 Pharmaceuticals Securities Corporation Massachusetts 100% X4 Therapeutics Inc. Delaware 100%

March 17, 2022 EX-10.19

Second Amended and Restated Executive Employment Agreement, dated as of March 7, 2022 by and between the Company and Adam S. Mostafa.

Exhibit 10.19 SECOND AMENDED AND RESTATED EXECUTIVE EMPLOYMENT AGREEMENT THIS SECOND AMENDED AND RESTATED EXECUTIVE EMPLOYMENT AGREEMENT (this ?Agreement?) is entered into as of March 7, 2022, (the ?Effective Date?) by and between X4 Pharmaceuticals, Inc. (the ?Company?), and Adam Mostafa (?Executive?) (collectively referred to as the ?Parties? or individually referred to as a ?Party?). R E C I T

March 17, 2022 EX-10.22

Amended and Restated Executive Employment Agreement, dated as of March 7, 2022 by and between the Company and Diego Cadavid

Exhibit 10.22 AMENDED AND RESTATED EXECUTIVE EMPLOYMENT AGREEMENT THIS AMENDED AND RESTATED EXECUTIVE EMPLOYMENT AGREEMENT (this ?Agreement?) is entered into as of March 7, 2022, (the ?Effective Date?) by and between X4 Pharmaceuticals, Inc. (the ?Company?), and Dr. Diego Cadavid (?Executive?) (collectively referred to as the ?Parties? or individually referred to as a ?Party?). R E C I T A L S WHE

March 17, 2022 EX-10.23

Amended and Restated Executive Employment Agreement, dated as of March 7, 2022 by and between the Company and Mary DiBiase

Exhibit 10.23 AMENDED AND RESTATED EXECUTIVE EMPLOYMENT AGREEMENT THIS AMENDED AND RESTATED EXECUTIVE EMPLOYMENT AGREEMENT (this ?Agreement?) is entered into as of March 7, 2022 (the ?Effective Date?) by and between X4 Pharmaceuticals, Inc. (the ?Company?), and Mary DiBiase, Ph.D. (?Executive?) (collectively referred to as the ?Parties? or individually referred to as a ?Party?). R E C I T A L S WH

March 17, 2022 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) x ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2021 or o ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission File Number: 001-38295 X4 PHARMACEUTICALS

March 17, 2022 EX-10.20

Amended and Restated Executive Employment Agreement, dated as of March 7, 2022 by and between the Company and Derek Meisner

Exhibit 10.20 AMENDED AND RESTATED EXECUTIVE EMPLOYMENT AGREEMENT THIS AMENDED AND RESTATED EXECUTIVE EMPLOYMENT AGREEMENT (this ?Agreement?) is entered into as of March 7, 2022, (the ?Effective Date?) by and between X4 Pharmaceuticals, Inc. (the ?Company?), and Derek M. Meisner (?Executive?) (collectively referred to as the ?Parties? or individually referred to as a ?Party?). R E C I T A L S WHER

March 10, 2022 S-8

As filed with the Securities and Exchange Commission on March 10, 2022

S-8 1 a032022s-8.htm S-8 As filed with the Securities and Exchange Commission on March 10, 2022 Registration No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM S-8 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 X4 Pharmaceuticals, Inc. (Exact name of registrant as specified in its charter) Delaware 27-3181608 (State or other jurisdiction of incorporation

March 10, 2022 EX-FILING FEES

Filing Fee Table

EX-FILING FEES 2 ex107calculationoffilingfee.htm EX-FILING FEES Calculation of Filing Fee Table Form S-8 (Form Type) X4 Pharmaceuticals, Inc. (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered Security Type Security Class Title Fee Calculation Rule Amount to be Registered (1) Proposed Maximum Offering Price Per Unit Maximum Aggregate Offering Price Fee Rate Amount of

March 3, 2022 EX-10.2

Registration Rights Agreement, dated March 3, 2022, by and among X4 Pharmaceuticals, Inc. and the persons party thereto.

Exhibit 10.2 REGISTRATION RIGHTS AGREEMENT This REGISTRATION RIGHTS AGREEMENT (this ?Agreement?) is made and entered into as of March 3, 2022 by and among X4 Pharmaceuticals, Inc., a Delaware corporation (the ?Company?), and the ?Investors? named in that certain Securities Purchase Agreement by and among the Company and the Investors, dated as of March 3, 2022 (the ?Purchase Agreement?). Capitaliz

March 3, 2022 EX-10.1

Securities Purchase Agreement, dated March 3, 2022, by and among X4 Pharmaceuticals, Inc. and the persons party thereto.

Exhibit 10.1 SECURITIES PURCHASE AGREEMENT This SECURITIES PURCHASE AGREEMENT (this ?Agreement?) is made and entered into as of March 3, 2022 by and among X4 Pharmaceuticals, Inc., a Delaware corporation (the ?Company?), and the Investors identified on Exhibit A attached hereto (each an ?Investor? and collectively the ?Investors?). For the avoidance of doubt, to the extent that only one Investor i

March 3, 2022 8-K

Entry into a Material Definitive Agreement, Unregistered Sales of Equity Securities, Financial Statements and Exhibits, Other Events

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 (Data of earliest event reported): March 3, 2022 X4 PHARMACEUTICALS, INC. (Exact name of registrant as specified in its charter) Delaware 001-38295 27-3181608 (State or other jurisdiction of incorporation) (Commission

March 3, 2022 EX-4.1

Form of March 2022 Prefunded Warrant

Exhibit 4.1 FORM THESE SECURITIES REPRESENTED HEREBY AND THE SECURITIES ISSUABLE UPON EXERCISE OF THESE SECURITIES HAVE NOT BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE BUT HAVE BEEN OR WILL BE ISSUED IN RELIANCE UPON AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED, AND, ACCORDINGLY, MAY NOT BE TRANSFERRED UNLESS

February 14, 2022 SC 13G/A

XFOR / X4 Pharmaceuticals Inc / BIOTECHNOLOGY VALUE FUND L P - AMENDMENT NO. 3 TO THE SCHEDULE 13G Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G (Rule 13d-102) INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULES 13d-1(b), (c), AND (d) AND AMENDMENTS THERETO FILED PURSUANT TO RULE 13d-2(b) (Amendment No. 3)1 X4 Pharmaceuticals, Inc. (Name of Issuer) Common Stock, $0.001 par value (Title of Class of Securities) 98420X103 (CUSIP Number) December

February 14, 2022 SC 13G/A

XFOR / X4 Pharmaceuticals Inc / Point72 Asset Management, L.P. - SCHEDULE 13G (AMENDMENT NO. 1) Passive Investment

240.13d-102 Schedule 13G - Information to be included in statements filed pursuant to 240.13d-1(b), (c), and (d) and amendments thereto filed pursuant to 240.13d-2. Securities and Exchange Commission, Washington, D.C. 20549 Schedule 13G Under the Securities Exchange Act of 1934 (Amendment No.1)* (Name of Issuer) X4 Pharmaceuticals, Inc. (Title of Class of Securities) Common Stock, Par Value $0.001

February 14, 2022 SC 13G/A

XFOR / X4 Pharmaceuticals Inc / Bain Capital Life Sciences Fund, L.P. - SC 13G/A Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 SCHEDULE 13G (Rule 13d-102) Information to be Included in Statements Filed Pursuant to ? 240.

February 14, 2022 EX-99.1

JOINT FILING AGREEMENT February 14, 2022

EXHIBIT 99.1 JOINT FILING AGREEMENT February 14, 2022 Pursuant to and in accordance with the Securities Exchange Act of 1934, as amended (the ?Act?), and the rules and regulations thereunder, each party hereto hereby agrees to the joint filing, on behalf of each of them, of any filing required by such party under Section 13 or Section 16 of the Act or any rule or regulation thereunder (including a

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