xfor-20260320

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

(AMENDMENT NO. )

Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐

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☐						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 § 240.14a-12

X4 Pharmaceuticals, Inc.

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement if Other Than the Registrant)

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No fee required.

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Fee paid previously with preliminary materials.

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Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rule 14a-6(i)(1) and 0-11

X4 PHARMACEUTICALS, INC.

61 North Beacon Street, 4th Floor

Boston, Massachusetts 02134

NOTICE OF ANNUAL MEETING OF STOCKHOLDERS

To Be Held On May 11, 2026

Dear Stockholder of X4 Pharmaceuticals, Inc.:

You are cordially invited to attend the 2026 Annual Meeting of Stockholders (the “Annual Meeting”) of X4 Pharmaceuticals, Inc., a Delaware corporation (the “Company”) on Monday, May 11, 2026 at 12:00 p.m. Eastern Time. The Annual Meeting will be held virtually via live audio-only webcast at www.virtualshareholdermeeting.com/XFOR2026. The Annual Meeting will be held online only. The Annual Meeting will be held for the following purposes:

1. To elect the three Class III director nominees named in the accompanying proxy statement (the “Proxy Statement”), to serve until the 2029 Annual Meeting of Stockholders and until their successors are duly elected and qualified.

2. To ratify the selection of PricewaterhouseCoopers LLP as the Company’s independent registered public accounting firm for the year ending December 31, 2026.

3. To approve the Second Amended and Restated 2017 Equity Incentive Plan to increase the number of shares available for issuance thereunder.

4. To approve, on a non-binding, advisory basis, the compensation of the Company’s named executive officers.

5. To conduct any other business as may properly come before the Annual Meeting or any adjournments or postponements thereof.

These items of business are more fully described in the Proxy Statement accompanying this Notice.

The Board of Directors has fixed March 13, 2026 as the record date for the Annual Meeting. Only stockholders of record at the close of business on that date will be entitled to notice of, and to vote at, the Annual Meeting or any adjournments or postponements thereof.

Instructions for accessing the virtual Annual Meeting are provided in the Proxy Statement. Unless otherwise announced differently at the meeting or on the meeting website, in the event of a technical malfunction or other situation that the meeting chair determines may affect the ability of the Annual Meeting to satisfy the requirements for a meeting of stockholders to be held by means of remote communication under the Delaware General Corporation Law, or that otherwise makes it advisable to adjourn the Annual Meeting, the meeting chair or secretary will convene the meeting at 12:00 p.m. Eastern Time on the date specified above and at the Company’s address specified above solely for the purpose of adjourning the meeting to reconvene at a date, time and physical or virtual location announced by the meeting chair or secretary. Under either of the foregoing circumstances, we will post information regarding the announcement on the Investors page of the Company’s website at https://investors.x4pharma.com/.

By Order of the Board of Directors,


David Kirske
Chief Financial Officer, Treasurer and Corporate Secretary

Boston, Massachusetts

March 20, 2026


			You are cordially invited to attend the Annual Meeting. Whether or not you expect to attend the Annual Meeting, please vote online or, if you requested printed copies of the proxy materials, by telephone or by completing, dating, signing and returning the proxy card or voting instruction form mailed to you, as promptly as possible in order to ensure your representation at the Annual Meeting. If you participate virtually in the annual meeting, you may vote at that time, even if you previously submitted your vote. Please note, however, that if your shares are held of record by a broker, fiduciary or custodian and you wish to vote at the Annual Meeting, you must obtain a proxy issued in your name from that record holder in order to vote your shares that are held in such agent’s name and account.

LEGAL MATTERS

Important Notice Regarding the Availability of Proxy Materials for the 2026 Annual Meeting of Stockholders to Be Held on May 11, 2026. The Proxy Statement and Annual Report for the year ended December 31, 2025 are available at www.proxyvote.com.

Forward-Looking Statements. The Proxy Statement contains “forward-looking statements” within the meaning of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995, which statements are subject to substantial risks and uncertainties and are based on estimates and assumptions. All statements other than statements of historical fact included in the Proxy Statement, including statements about the Company’s Board of Directors, corporate governance practices and executive compensation program and equity compensation utilization, are forward-looking statements. In some cases, you can identify forward-looking statements by terms such as “may,” “might,” “will,” “objective,” “intend,” “should,” “could,” “can,” “would,” “expect,” “believe,” “design,” “estimate,” “predict,” “potential,” “plan” or the negative of these terms, and similar expressions intended to identify forward-looking statements. These statements involve known and unknown risks, uncertainties and other factors that could cause our actual results to differ materially from the forward-looking statements expressed or implied in the Proxy Statement. Such risks, uncertainties and other factors include those risks described in “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” in the Company’s most recent Annual Report on Form 10-K filed with the U.S. Securities and Exchange Commission (“SEC”) and other subsequent documents we file with the SEC. The Company expressly disclaims any obligation to update or alter any statements whether as a result of new information, future events or otherwise, except as required by law.

Website References. Website references throughout this document are inactive textual references and provided for convenience only, and the content on the referenced websites is not incorporated herein by reference and does not constitute a part of the Proxy Statement.

TABLE OF CONTENTS


			Page

QUESTIONS AND ANSWERS ABOUT THESE PROXY MATERIALS AND VOTING			1
PROPOSAL 1 ELECTION OF DIRECTOR			5
INFORMATION REGARDING THE BOARD OF DIRECTORS AND CORPORATE GOVERNANCE			8
Independence of the Board of Directors			8
Board Leadership Structure			8
Role of the Board in Risk Oversight			8
Meetings of the Board of Directors			9
Information Regarding Committees of the Board of Directors			9
Audit Committee			9
Compensation Committee			12
Nominating and Corporate Governance Committee			13
Stockholder Communications with the Board of Directors			14
Code of Ethics			14
Insider Trading Policy			16
PROPOSAL 2 RATIFICATION OF SELECTION OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM			16
PROPOSAL 3: APPROVAL OF THE SECO ND AMENDED AND RESTATED 2017 EQUITY INCENTIVE PLAN			19
PROPOSAL 4 NON-BINDING ADVISORY VOTE ON NAMED EXECUTIVE OFFICER COMPENSATION			24
EXECUTIVE OFFICERS			25
PRINCIPAL STOCKHOLDERS			26
EXECUTIVE COMPENSATION			30
Summary Compensation Table			30
Narrative to Summary Compensation Table			31
Outstanding Equity Awards at Fiscal Year-End			35
Director Compensation Table			38
Narrative to Director Compensation Table			39
SECURITIES AUTHORIZED FOR ISSUANCE UNDER EQUITY COMPENSATION PLANS			41
TRANSACTIONS WITH RELATED PERSONS			42
Related-Person Transactions Policy and Procedures			42
Certain Related-Person Transactions			42
HOUSEHOLDING OF PROXY MATERIALS			43
OTHER MATTERS			44

X4 PHARMACEUTICALS, INC.

61 North Beacon Street, 4th Floor

Boston, Massachusetts 02134

PROXY STATEMENT

FOR THE 2026 ANNUAL MEETING OF STOCKHOLDERS

May 11, 2026

QUESTIONS AND ANSWERS ABOUT THESE PROXY MATERIALS AND VOTING

What is the purpose of these proxy materials?

We are making these proxy materials available to you in connection with the solicitation of proxies by the Board of Directors (the “Board”) of X4 Pharmaceuticals, Inc. (“we,” “us,” “our” or the “Company”) for use at the 2026 Annual Meeting of Stockholders (the “Annual Meeting”) to be held virtually on May 11, 2026 at 12:00 p.m. Eastern Time, or at any other time following adjournment or postponement thereof. You are invited to participate in the Annual Meeting and to vote on the proposals described in this proxy statement (the “Proxy Statement”). The proxy materials are being made available to our stockholders beginning on or about March 20, 2026.

Why did I receive a notice regarding the availability of proxy materials on the Internet?

Pursuant to rules adopted by the Securities and Exchange Commission (the “SEC”), we have elected to provide access to our proxy materials over the Internet. This process allows us to expedite our stockholders’ receipt of proxy materials, lower the costs of printing and mailing the proxy materials and reduce the environmental impact of our Annual Meeting. If you received a Notice of Internet Availability of Proxy Materials (the “Notice”), you will not receive a printed copy of the proxy materials unless you request one. The Notice provides instructions on how to access the proxy materials for the Annual Meeting via the Internet, how to request a printed set of proxy materials and how to vote your shares.

Will I receive any other proxy materials by mail?

We may elect, in our discretion, to send you a proxy card, along with a second Notice, on or after ten calendar days have passed since our first mailing of the Notice.

Why are we holding a virtual Annual Meeting?

We have adopted a virtual meeting format for the Annual Meeting to provide a consistent experience to all stockholders regardless of geographic location. We believe this expands stockholder access, improves communications and lowers our costs while reducing the environmental impact of the meeting. In structuring our virtual Annual Meeting, our goal is to enhance rather than constrain stockholder participation in the meeting, and we have designed the meeting to provide stockholders with the same rights and opportunities to participate as they would have at an in-person meeting.

Who can vote at the Annual Meeting?

Only stockholders of record at the close of business on March 13, 2026 (the “Record Date”) will be entitled to vote at the Annual Meeting. At the close of business on the Record Date, there were 90,919,696 shares of common stock issued and outstanding. A list of stockholders entitled to vote at the Annual Meeting will be available at our principal executive offices for examination during normal business hours by any stockholder for any purpose germane to the Annual Meeting for a period of ten days ending the day prior to the Annual Meeting.

What is the difference between holding shares as a registered stockholder and as a beneficial owner?

Stockholder of Record: Shares Registered in Your Name

If on the Record Date, your shares of common stock were registered directly in your name with our transfer agent, Computershare Trust Company, N.A., then you are considered to be, with respect to those shares of common stock, a stockholder of record, and these proxy materials are being sent directly to you by us.

Beneficial Owner: Shares Registered in the Name of a Broker, Fiduciary or Custodian

If on the Record Date, your shares of common stock are held by a broker, fiduciary or custodian, then you are considered the beneficial owner of shares of common stock held in “street name” and these proxy materials are being forwarded to you from that broker, fiduciary or custodian.

How do I attend the Annual Meeting?

The meeting will be held virtually on Monday, May 11, 2026, at 12:00 p.m. Eastern Time. Stockholders of record as of the close of business on the Record Date are entitled to participate in and vote at the Annual Meeting. To participate in the Annual Meeting, stockholders of record should go to the meeting website at www.virtualshareholdermeeting.com/XFOR2026, where they will be able to listen to the Annual Meeting live, submit questions and vote online. If your shares are held in street name and your voting instruction form or Notice indicates that you may vote those shares through www.proxyvote.com, then you may access, participate in and vote at the Annual Meeting with the unique 16-digit control number indicated on that voting instruction form or Notice. Otherwise, stockholders who hold their shares in street name should contact their bank, broker or other nominee (preferably at least five days before the Annual Meeting) and obtain a “legal proxy” in order to be able to attend, participate in or vote at the Annual Meeting.

We will endeavor to answer as many stockholder-submitted questions as time permits that comply with the Annual Meeting rules of conduct. We reserve the right to edit profanity or other inappropriate language and to exclude questions regarding topics that are not pertinent to meeting matters or Company business. If we receive substantially similar questions, we may group such questions together and provide a single response to avoid repetition.

We encourage you to access the Annual Meeting 15 minutes prior to the start time to allow time for online check-in. If you experience technical difficulties during the Annual Meeting, you should call the technical support phone number provided when you log in to the Annual Meeting. Additional information regarding the rules and procedures for participating in the Annual Meeting will be set forth in our meeting rules of conduct, which stockholders can view during the meeting at the meeting website.

What am I voting on?

There are three matters scheduled for a vote:

•Election of the three Class III director nominees to serve until the 2029 Annual Meeting of Stockholders (“Proposal 1”);

•Ratification of the selection of PricewaterhouseCoopers LLP as the Company’s independent registered public accounting firm for the year ending December 31, 2026 (“Proposal 2”);

•Approval of the Second Amended and Restated 2017 Equity Incentive Plan (“Proposal 3”); and

•Approval, on a non-binding, advisory basis of the compensation of the Company’s named executive officers (“Proposal 4”).

The Board recommends that you vote your shares “FOR” each director nominee in Proposal 1 and “FOR” Proposals 2, 3 and 4.

What if another matter is properly brought before the Annual Meeting?

As of the date of filing this Proxy Statement, the Board knows of no other matters that will be presented for consideration at the Annual Meeting. If any other matters are properly brought before the meeting, it is the intention of the persons named in the accompanying proxy to vote on those matters in accordance with their best judgment.

How do I vote?

Even if you plan to attend the Annual Meeting, we recommend that you also submit your vote as early as possible in advance so that your vote will be counted if you later decide not to, or are unable to, virtually attend the Annual Meeting.

With respect to Proposal 1, you may either vote “FOR” the nominee to the Board or “WITHHOLD” for the nominee. With respect to Proposals 2, 3 and 4, you may vote “FOR” or “AGAINST” or abstain from voting.

The procedures for voting are as follows:

Stockholder of Record: Shares Registered in Your Name

If you are a stockholder of record, you may vote your shares online during the virtual Annual Meeting (see “How do I attend the Annual Meeting?” above) or by proxy in advance of the Annual Meeting by Internet (at www.proxyvote.com) or, if you requested paper copies of the proxy materials, by completing and mailing a proxy card or by telephone at 1-800-690-6903.

Beneficial Owner: Shares Registered in the Name of a Broker, Fiduciary or Custodian

If you are the beneficial owner, you may vote your shares online during the virtual Annual Meeting (see “How do I attend the Annual Meeting?” above) or you may direct your broker, fiduciary or custodian how to vote in advance of the Annual Meeting by following the instructions they provide.

How many votes do I have?

On each matter to be voted upon, you have one vote for each share of common stock you own as of the Record Date.

If I am a stockholder of record and I do not vote, or if I return a proxy card or otherwise vote without giving specific voting instructions, what happens?

If you are a stockholder of record and do not vote by completing a proxy card, by telephone, through the Internet or electronically at the Annual Meeting, your shares will not be voted and will not be counted toward the quorum requirement.

The shares represented by each signed and returned proxy will be voted at the Annual Meeting by the persons named as proxies in the proxy card in accordance with the instructions indicated on the proxy card. However, if you are the registered stockholder and sign and return your proxy card without giving specific instructions, the persons named as proxies in the proxy card will vote your shares in accordance with the recommendations of the Board. Your shares will be counted toward the quorum requirement. If any other matter is properly presented at the Annual Meeting, the persons named as proxies in the proxy card will vote your shares using his or her best judgment.

If I am a beneficial owner of shares held in street name and I do not vote, or if I return a proxy card or otherwise vote without giving specific voting instructions, what happens?

If you are a beneficial owner of shares held in street name and you do not instruct your broker, fiduciary or custodian how to vote your shares, your broker, fiduciary or custodian will only be able to vote your shares with respect to proposals considered to be “routine.” Your broker, fiduciary or custodian is not entitled to vote your shares with respect to “non-routine” proposals, which we refer to as a “broker non-vote.” Whether a proposal is considered routine or non-routine is subject to stock exchange rules and final determination by the stock exchange. Even with respect to routine matters, some brokers are choosing not to exercise discretionary voting authority. As a result, we urge you to direct your broker, fiduciary or custodian how to vote your shares on all proposals to ensure that your vote is counted.

Who is paying for this proxy solicitation?

We will pay for the entire cost of soliciting proxies. In addition to these proxy materials, our directors and employees may also solicit proxies in person, by telephone, or by other means of communication. Directors and employees will not be paid any additional compensation for soliciting proxies. We may also reimburse brokerage firms, banks and other agents for the cost of forwarding proxy materials to beneficial owners.

What does it mean if I receive more than one Notice?

If you receive more than one Notice, your shares may be registered in more than one name or in different accounts. Please follow the voting instructions on each of the Notices to ensure that all of your shares are voted.

Can I change my vote after submitting my proxy?

Stockholder of Record: Shares Registered in Your Name

Yes. If you are the stockholder of record, you can revoke your proxy at any time before the final vote at the Annual Meeting in any one of the following ways:


			•						You may submit another properly completed proxy card with a later date (which automatically revokes the earlier proxy).


			•						You may grant a subsequent proxy by telephone or through the Internet.


			•						You may send a timely written notice that you are revoking your proxy to our Corporate Secretary at 61 North Beacon Street, 4th Floor, Boston, Massachusetts 02134.


			•						You may attend the Annual Meeting virtually and vote in person. Simply attending the Annual Meeting virtually will not, by itself, revoke your proxy.

Your last submitted vote is the one that is counted.

Beneficial Owner: Shares Registered in the Name of Broker, Fiduciary or Custodian

If you are the beneficial owner, you must follow the instructions provided by your broker, fiduciary or custodian with respect to changing your vote.

What is the quorum requirement?

A quorum of stockholders is necessary to hold a valid meeting. A quorum will be present if stockholders holding at least a

majority in voting power of the outstanding shares entitled to vote are present at the Annual Meeting in person or represented

by proxy.

Your shares will be counted towards the quorum only if you submit a valid proxy (or one is submitted on your behalf by your

broker, fiduciary or custodian) or if you vote electronically the Annual Meeting. Abstentions and broker non-votes, if any, will be counted towards the quorum requirement. If there is no quorum, the chairman of the meeting or holders of a majority of shares present at the Annual Meeting in person or represented by proxy may adjourn the Annual Meeting to another date.

How many votes are needed to approve each proposal and how are votes counted?

The following table summarizes the minimum vote needed to approve each proposal and the effect of abstentions and broker non-votes.

Proposal

Number

Proposal Description

Vote Required for Approval

Effect of

Abstentions

Effect of Broker

Non-Votes

Election of directors

Each of the three nominees must receive a plurality of votes cast “FOR” his or her election. “Plurality” means that the individuals who receive the highest number of votes cast “FOR” are elected as directors.

Not applicable

No effect

Ratification of independent auditor selection

“FOR” votes from the holders of shares representing a majority of votes cast.

No effect

Approve equity incentive plan share increase

“FOR” votes from the holders of shares representing a majority of votes cast.

No effect

Non-binding advisory vote on executive compensation

“FOR” votes from the holders of shares representing a majority of votes cast.

No effect

Votes will be counted by Broadridge Financial Solutions or its associates, the Inspector of Elections appointed for the Annual Meeting.

How can I find out the results of the voting at the Annual Meeting?

We expect to announce preliminary voting results at the Annual Meeting. Final voting results will be published in a Current Report on Form 8-K to be filed with the SEC within four business days after the Annual Meeting.

PROPOSAL 1

ELECTION OF DIRECTORS

In accordance with our Certificate of Incorporation and Bylaws, the Board has fixed the number of directors constituting the Board at five. Our Board is divided into three classes. Each class consists, as nearly as possible, of one-third of the total number of directors, and each class has a staggered three-year term. Vacancies on the Board may be filled only by persons elected by a majority of the remaining directors. A director elected by the Board to fill a vacancy in a class, including vacancies created by an increase in the number of directors, shall serve for the remainder of the full term of that class and until the director’s successor is duly elected and qualified.

At the Annual Meeting, the stockholders will vote to elect the three Class III director nominees named in this Proxy Statement to serve until the 2029 Annual Meeting of Stockholders and until their successors are duly elected and qualified or until their earlier resignation or removal. Our Board has nominated Gary J. Bridger, Ph.D., Françoise De Craecker, and Murray W. Stewart, M.D. for election to our Board. Dr. Bridger, Ms. De Craecker and Dr. Stewart were most recently elected by stockholders at the 2023 Annual Meeting of Stockholders.

Our director nominees have indicated that they are willing and able to serve as directors. However, if any of them becomes unable or, for good cause, unwilling to serve, proxies may be voted for the election of such other person as shall be designated by our Board, or the Board may decrease the size of the Board. There are no family relationships between or among any of our directors. There is no arrangement or understanding between any of our directors and any other person or persons pursuant to which he or she is to be selected as a director or nominee.

Director Nominee and Continuing Directors

There is currently one Class I director, whose term expires at the 2027 Annual Meeting of Stockholders; one Class II director, whose term expires at the 2028 Annual Meeting of Stockholders; and three Class III directors, who are up for election at this meeting for a term expiring at the 2029 Annual Meeting of Stockholders.


Name	Class	Age (as of March 20)	Position
Michael S. Wyzga (1)(2)	I	71	Lead Independent Director
Adam R. Craig, M.D., Ph.D., M.B.A.	II	60	Executive Chairman
Gary J. Bridger, Ph.D. (2)(3)	III	63	Director
Françoise De Craecker (2)(3)	III	64	Director
Murray W. Stewart, M.D. (3)	III	65	Director

(1) Member of the Nominating and Corporate Governance Committee

(2) Member of the Audit Committee

(3) Member of the Compensation Committee

The following is a brief biography and the ages of the nominees and each director whose term will continue after the Annual Meeting, and a discussion of the specific experience, qualifications, attributes or skills of each nominee that led the Nominating and Corporate Governance Committee to recommend the person as a nominee for director, as of the date of this Proxy Statement.

Class III Director Nominees to Serve Until the 2029 Annual Meeting of Stockholders

Gary J. Bridger, Ph.D., age 63, became a member of the board of directors of X4 Pharmaceuticals, Inc., a private company, in October 2018 and continues to serve as a member of our Board upon the completion of our merger, between Arsanis, Inc. and the Company, in March 2019. From February 2015 to December 2017, Dr. Bridger served as a consultant to Xenon Pharmaceuticals Inc., a biopharmaceutical company, where he previously served as the Executive Vice President of Research and Development from January 2013 to February 2015. From October 2013 to October 2015, Dr. Bridger served as a Managing Director at Five Corners Capital Inc. From June 2010 to June 2012, Dr. Bridger served as a venture partner at Venture West Capital Management, a venture capital firm. From November 2006 to December 2007, Dr. Bridger served as Senior Vice President of Research and Development of Genzyme Corporation, a biotechnology company, which was acquired by Sanofi, S.A. In June 1996, Dr. Bridger co-founded AnorMED Inc., a biopharmaceutical company, and was its Vice President of Research and Development and Chief Scientific Officer from 2000 until its acquisition by Genzyme in November 2006. Dr. Bridger has served as the Interim Chief Scientific Officer at Liminal BioSciences Inc., a privately held

biotechnology company, since November 2022, and on their board of directors from May 2019 until September 2023, and previously served on the board of directors of Alder BioPharmaceuticals, Inc., a biopharmaceutical company, from 2013 to 2016 and Aquinox Pharmaceuticals Inc., a pharmaceuticals company, from 2015 until 2019. Dr. Bridger serves on the scientific advisory board of Alectos Therapeutics Inc., a biopharmaceutical company and formerly served on the board of directors of Expansion Therapeutics, Inc., a biotechnology company, from January 2022 to June 2025. Dr. Bridger holds a Ph.D. in Organic Chemistry from the University of Manchester Institute of Science and Technology.

We believe that Dr. Bridger’s experience as an executive officer or director of several public and private life sciences companies provides him with the qualifications and skills to serve on our Board.

Françoise De Craecker, age 64, has served as a member of our Board since October 2021. Ms. De Craecker has served as an Independent Director of Gensight Biologics, a biopharma company focused on developing and commercializing innovative gene therapies for retinal neurodegenerative diseases and central nervous system disorders, since May 2021. Ms. De Craecker has also served as non-executive director of Kyowa Kirin International, a subsidiary of Kyowa Kirin Co., Ltd. a Japan-based global specialty pharmaceutical company, since April 2024. Previously, from January 2018 to August 2019, Ms. De Craecker was the General Manager of the Europe, Middle East & Africa region at AveXis (now Novartis Gene Therapies), a biotechnology company that develops and commercializes gene therapies for rare and life-threatening neurological genetic disorders. From August 2014 to December 2017, Ms. De Craecker served as Senior Vice President and General Manager of the Europe, Middle East & Africa region at Raptor Pharmaceuticals, a biopharmaceutical company since acquired by Horizon Pharmaceuticals and after by Chiesi Farmaceutici. Earlier in her career, Ms. De Craecker held multiple positions of increasing responsibility and in diverse geographies at Shire Human Genetics Rare Disease Business Unit (previously Transkaryotic Therapies), from October 2000 to March 2014, including Vice President and General Manager of Europe, Vice President and General Manager of Northern Europe, Senior Director European Mid-Sized Countries and Global Fabry Disease Franchise Lead. Ms. De Craecker received her Masters in Nutrition Science from Faculty of Medicine of the University of Leuven (Belgium).

We believe that Ms. De Craecker’s experience with and knowledge of life sciences companies in the development and commercialization space provide her with the qualifications and skills to serve on our Board.

Murray W. Stewart, M.D., age 65, has served as a member of our Board since March 2019 and as our interim Chief Medical Officer from November 2022 to September 2023. In March 2025, Dr. Stewart was appointed to the board of directors of CAMP4 Therapeutics Corporation, a publicly traded biotechnology company (Nasdaq: CAMP). From July 2021 to May 2023, Dr. Stewart served on the board of directors of VectivBio Holding AG (Nasdaq: VECT) and was a member of the compensation committee. Additionally, from January 2023 to March 2023, Dr. Stewart served as a member of the board of directors of Amarin Corporation plc (Nasdaq: AMRN). Dr. Stewart has served as Senior Medical Advisor of Rhythm Pharmaceuticals, Inc., a biopharmaceutical company focused on developing and commercializing therapies for the treatment of rare genetic disorders of obesity, since September 2021, and previously served as Chief Medical Officer from October 2018 until September 2021. He previously served as Head of Research and Development for Novelion Therapeutics Inc., a biopharmaceutical company focused on developing new standards of care for individuals living with rare disease, from November 2017 to October 2018. Prior to that, Dr. Stewart held various positions of increasing responsibility at GlaxoSmithKline, including serving as Chief Medical Officer from April 2014 to November 2017, with global responsibility for patient well-being across the vaccine, pharmaceutical, and consumer business units. He also held multiple research and development leadership roles, including Chief Medical Officer for the pharmaceutical business, Clinical Head of the Biopharma Unit, and Therapy Area Head for metabolic and cardiovascular diseases. Prior to his tenure to joining GlaxoSmithKline, he worked as a consultant physician and honorary senior lecturer at the Diabetes Center in Newcastle upon Tyne in the United Kingdom. Dr. Stewart holds an M.D. from Southampton Medical School and is a Fellow of the Royal College of Physicians.

We believe that Dr. Stewart’s extensive biopharmaceutical leadership experience, including experience in research, clinical development and regulatory strategy, provide him with the qualifications and skills to serve on our Board.

Class I Director Continuing in Office Until the 2027 Annual Meeting of Stockholders

Michael S. Wyzga, age 71, became a member of the board of directors of X4 Pharmaceuticals, Inc., a private company, in July 2018 and continues to serve as a member of our Board following the completion of the Merger in March 2019. He served as our Chairman until August 2025, and as our Lead Independent Director since August 2025. Mr. Wyzga is currently the President of MSW Consulting Inc., a strategic consulting group focused in the life sciences area. From December 2011 until November 2013, Mr. Wyzga served as President and Chief Executive Officer and a member of the board of directors of Radius Health, Inc., a publicly traded biopharmaceutical company. Prior to that, Mr. Wyzga served in various senior

management positions at Genzyme Corporation, a publicly traded global biotechnology company. Mr. Wyzga joined Genzyme in February 1998 and most recently served as Executive Vice President, Finance from May 2003 until November 2011 and as Chief Financial Officer from July 1999 until November 2011. Mr. Wyzga is also a member of the boards of directors of GenSight Biologics S.A., a Euronext traded biopharmaceutical company, where he has served since February 2016 and currently holds the position as Chairman of the board of directors; Tvardi Therapeutics, Inc., a biotechnology company (Nasdaq: TVRD), where he has served since March 2021; and Mereo BioPharma Group plc (formerly Oncomed Pharmaceuticals, Inc.) (Nasdaq: MREO), a biopharmaceutical company, where he currently serves as Chairman of the board of directors. He previously served on the board of directors at Invivyd, Inc., a publicly traded biopharmaceutical company from 2022 to May 2024 (Nasdaq: IVVD) and previously held the position of chair of the audit committee and was a member of the compensation committee; LogicBio Therapeutics, Inc. (formerly Nasdaq: LOGC) from September 2018 to November 2022; and Exact Sciences Corporation, a publicly traded medical technology company (Nasdaq: EXAS), from February 2015 to June 2021. He received an M.B.A. from Providence College and a B.S. from Suffolk University.

We believe that Mr. Wyzga’s senior management experience at biopharmaceutical and biotechnology companies, his current and past experience on boards of directors of public companies, and his financial expertise qualify him to serve as a member of our Board.

Class II Director Continuing in Office Until the 2028 Annual Meeting of Stockholders

Adam R. Craig, M.D., Ph.D., M.B.A., Dr. Craig, age 60, has served as our Executive Chairman since August 2025. Prior to joining the Company, he most recently served as the Interim President and Chief Executive Officer of Stratus Therapeutics, Inc. (“Stratus Therapeutics,” formerly known as Garuda Therapeutics, Inc.) from August 2024 until March 2025. He currently serves on the board of directors of eGenesis, a private biotechnology company. Dr. Craig also served as President, Chief Executive Officer and Interim Chief Medical Officer of CTI BioPharma Corp. (“CTI BioPharma”) and as a member of its board of directors from March 2017 until June 2023. He is a physician and experienced biopharmaceutical industry leader with extensive expertise in corporate strategic operations and governance, investor relations and financing; U.S. and EU regulatory engagement; and medical affairs and hematology and oncology research. Prior to CTI BioPharma, Dr. Craig worked as an independent consultant providing strategic and operational advice and support to CTI BioPharma and other hematology/oncology biotechnology companies since 2016. Prior to consulting, Dr. Craig was Chief Medical Officer and Executive Vice President of Development of Sunesis Pharmaceuticals, a biopharmaceutical company developing novel targeted inhibitors for the treatment of hematologic and solid cancers, from 2012 to 2016. From 2008 to 2012, Dr. Craig was Chief Medical Officer and Senior Vice President of Chemgenex Pharmaceuticals Ltd, a biotechnology company which was acquired by Cephalon/Teva Pharmaceuticals in 2011. He also served as a Product Development Reviewer for the Cancer Prevention Research Institute of Texas. Dr. Craig has been a member of the board of directors of Stratus Therapeutics since August 2024. Dr. Craig earned his Medical Degree from Charing Cross and Westminster Medical School, University of London, a Ph.D. in Molecular Oncology from Leeds University in the U.K. and an M.B.A. from The Open University Business School (U.K.). Dr. Craig completed post-graduate training in Paediatrics, Neonatology and Paediatric Oncology and is a Member of both the Royal College of Physicians (London) and the Royal College of Paediatrics and Child Health.

We believe that Dr. Craig’s experience as an executive in the pharmaceutical industry and knowledge of biopharmaceuticals provide him with the qualifications and skills to serve on our Board.

THE BOARD OF DIRECTORS RECOMMENDS

A VOTE “FOR” EACH OF THE CLASS III DIRECTOR NOMINEES.

INFORMATION REGARDING THE BOARD OF DIRECTORS AND CORPORATE GOVERNANCE

COMPOSITION OF THE BOARD OF DIRECTORS

The Board does not have specific diversity goals or a standalone diversity policy. The Board seeks director candidates who represent a mix of backgrounds and experiences that will enhance the quality of the Board’s deliberations and decisions. The Board recognizes the value of appointing individual directors who bring a variety of diverse viewpoints, backgrounds, skills, experiences and expertise to the Board. The Board believes that having a diverse board of directors fosters more productive and beneficial discussions and decision-making processes in support of the Company’s strategic objectives. The Board assesses its effectiveness in balancing these considerations in connection with its annual evaluation of the composition of the Board.

INDEPENDENCE OF THE BOARD OF DIRECTORS

Our Board determines the independence of our directors by applying the applicable rules, regulations and listing standards of the Nasdaq Stock Market (“Nasdaq”). These provide that a director is independent only if the Board affirmatively determines that the director does not have a relationship with us which, in the opinion of the Board, would interfere with the exercise of his or her independent judgment in carrying out the responsibilities of a director. Such relationships may include employment, commercial, accounting, family and other business, professional and personal relationships. As required under the Nasdaq listing standards, a majority of the members of a listed company’s board of directors must qualify as “independent,” as affirmatively determined by the Board of Directors.

Applying these standards, our Board reviews the independence of our directors, taking into account all relevant facts and circumstances. Our Board has determined that the following members of our Board are currently independent under Nasdaq listing rules: Dr. Bridger, Ms. De Craecker, Dr. Stewart, and Mr. Wyzga. Dr. Craig is employed by us and is therefore not independent under Nasdaq listing standards. In addition, former directors William Aliski, Allison Lawton, David McGirr and R. Keith Woods were independent during the period each served on the Board in 2025.

Our Board also determined that each of the directors currently serving on the Audit Committee and the Compensation Committee satisfy the heightened independence standards for audit committees and compensation committees, as applicable, established by the SEC and Nasdaq listing rules.

BOARD LEADERSHIP STRUCTURE

We do not have a policy regarding whether the roles of Chairman of the Board (the “Chair”) and the Chief Executive Officer should be separate or combined, and our Board believes that the Company should maintain its flexibility to determine the appropriate leadership structure. As such, the Board periodically reviews its leadership structure to evaluate whether the structure remains appropriate for the Company, and may modify this structure from time to time as and when appropriate to best address the Company’s unique circumstances and advance the best interests of all stockholders. At any time when the Chair is not independent, the Nominating and Corporate Governance Committee may designate an independent director to serve as “Lead Independent Director,” who shall be approved by a majority of the independent directors.

Currently, Dr. Craig serves as our Executive Chairman and is not an independent director of the Board. The independent directors have appointed Mr. Wyzga to serve as our Lead Independent Director. The Board believes this leadership model, together with all Board members other than the Chair being independent, all key committees of the Board being comprised solely of, and chaired by, independent directors, and the Company’s established Corporate Governance Guidelines, provides an effective leadership structure for the Company. Having an Executive Chairman fosters clear accountability, effective decision-making, and aligns corporate strategy with the Company’s day-to-day operations, particularly during this transition period for the Company, while our Lead Independent Director provides independent Board oversight of management.

The independent directors have the opportunity to meet in executive sessions without management present at every regular Board meeting. Our Lead Independent Director presides over these executive sessions. The purpose of these executive sessions is to encourage and enhance communication among independent directors.

The Board believes that its programs for overseeing risk, as described under “Role of the Board in Risk Oversight,” would be effective under a variety of leadership frameworks. Accordingly, the Board’s risk oversight function did not significantly impact its selection of the current leadership structure.

ROLE OF THE BOARD IN RISK OVERSIGHT

One of the Board’s key functions is informed oversight of our risk management process. The Board does not have a standing risk management committee, but rather administers this oversight function directly through the Board as a whole, as well as through various Board standing committees that address risks inherent in their respective areas of oversight. For example, in

determining whether and under what circumstances we will engage in financing transactions or enter into licensing, collaboration or similar arrangements, the Board is involved in our management of risks related to our financial condition or of the risks inherent in drug development and commercialization. As part of its oversight, our Board receives reports by each committee chair regarding the committee’s considerations and actions.

The Audit Committee is responsible for discussing the adequacy of our risk management activities with management and our independent registered public accounting firm. The Audit Committee’s primary emphasis is managing our financial risk exposures, including our internal control over financial reporting. The Audit Committee also monitors compliance with legal and regulatory requirements and considers and approves or disapproves any related person transactions. In addition, the Compensation Committee is responsible for considering whether our compensation programs and practices are reasonably likely to have a material adverse effect on us. The Nominating and Corporate Governance Committee assists the Board by overseeing and evaluating programs and risks associated with Board organization, membership and structure, and corporate governance.

At each of its meetings, the Board receives business updates from various members of management. These updates may identify matters that have emerged within that member of management’s scope of responsibility that involve operational, financial, legal or regulatory risks and, in these cases, the Board provides guidance to management. Our Board believes that full and open communication between management and the Board is essential for effective risk management and oversight.

In carrying out their risk oversight functions, the Board and its committees routinely request and review management updates, reports from the independent auditors and legal and regulatory advice from outside experts, as appropriate, to assist in discerning and overseeing important risks that may be faced by us. The Board continually evolves its risk oversight practices as appropriate given the stage of our evolution as a late-stage clinical biopharmaceutical company and the fast-paced changes of the life sciences industry.

MEETINGS OF THE BOARD OF DIRECTORS

The Board held twenty-one meetings during the last year. Each of our incumbent Board members attended 75% or more of the aggregate number of meetings of the Board and of the committees on which he or she served as a director or committee member during the period in which he or she was on the Board or Committee.

Directors are encouraged to attend the annual meeting of stockholders. Six of our directors then serving on the Board attended our 2025 Annual Meeting of Stockholders.

INFORMATION REGARDING COMMITTEES OF THE BOARD OF DIRECTORS

The Board has three standing committees: an Audit Committee, a Compensation Committee and a Nominating and Corporate Governance Committee. Each of these committees has authority to engage legal counsel or other experts or consultants, as it deems appropriate to carry out its responsibilities. The composition and function of each of these committees are described below.

Audit Committee

The Audit Committee is currently composed of three members: Mr. Wyzga (chair), Ms. De Craecker and Dr. Bridger. The Audit Committee met seven times during 2025. The Board has adopted a written Audit Committee charter that is available to stockholders on our website at http://investors.x4pharma.com/, under “Governance.”

The Audit Committee was established by the Board in accordance with Section 3(a)(58)(A) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), to oversee our corporate accounting and financial reporting processes and audits of our financial statements. For this purpose, the Audit Committee performs several functions. The Audit Committee:


			•						appoints, evaluates, retains, and when necessary, terminates the engagement of the independent auditors;


			•						oversees the independent auditor and approves the compensation of the independent auditor;


			•						reviews and approves the retention of the independent auditors to perform any proposed permissible non-audit services;


			•						oversees the work of the independent auditor, including resolution of disagreements between our management and the independent auditor regarding financial reporting;


			•						reviews our annual audited financial statements and quarterly financial statements with management and the independent auditor, including our disclosures under “Management’s Discussion and Analysis of Financial Condition and Results of Operations;”


			•						discusses the type and presentation of information to be disclosed in our earnings releases;


			•						coordinates the Board’s oversight of our internal control over financial reporting, disclosure procedures, cybersecurity and technology planning, and code of business conduct and ethics;


			•						discusses our policies with respect to risk assessment and risk management, including guidelines and policies to govern the process by which our exposure to risk is handled;


			•						establishes procedures, as required under applicable law, for the receipt, retention and treatment of complaints received by us regarding accounting, internal accounting controls or auditing matters and the confidential and anonymous submission by employees of concerns regarding questionable accounting or auditing matters;


			•						reviews our policies and procedures for reviewing and approving related person transactions;


			•						oversees the work of the internal auditors and internal audit functions, including evaluating whether the Company requires an internal audit function in order to improve the oversight of the integrity of the Company’s financial statements, the Company’s compliance with legal and regulatory requirements, and the Company’s overall audit function; and


			•						oversees and controls the Company’s cybersecurity policies and guidelines to prevent, detect, and respond to cyber incidents or data breaches involving the Company’s products, services, data, information systems, and business operations and reviews the effectiveness of the Company’s cybersecurity programs and its practices for identifying, assessing, and mitigating cybersecurity risks across the Company’s products, services, and business operations.

The Board has determined that Mr. Wyzga qualifies as an “audit committee financial expert,” as defined in applicable SEC rules.

Report of the Audit Committee of the Board of Directors

The material in this report is not “soliciting material,” is not deemed “filed” with the SEC and is not to be incorporated by reference in any filing of the Company under the Securities Act of 1933, as amended (the “Securities Act”) or the Exchange Act, whether made before or after the date hereof and irrespective of any general incorporation language in any such filing.

The Audit Committee is appointed by our Board to assist our Board in fulfilling its oversight responsibilities with respect to (1) the integrity of the Company’s financial statements and financial reporting process and systems of internal controls regarding finance, accounting, and compliance with legal and regulatory requirements, (2) the qualifications, independence, and performance of the Company’s independent registered public accounting firm, (3) the performance of the Company’s internal audit function, if any, and (4) other matters as set forth in the charter of the audit committee approved by our board of directors.

Management is responsible for the preparation of the Company’s financial statements and the financial reporting process, including its system of internal control over financial reporting and its disclosure controls and procedures. The independent registered public accounting firm is responsible for performing an audit of the Company’s financial statements in accordance with the standards of the Public Company Accounting Oversight Board (“PCAOB”), and issuing a report thereon. The Audit Committee’s responsibility is to monitor and oversee these processes.

The Audit Committee has reviewed and discussed the audited financial statements for the year ended December 31, 2025 with management of the Company. The Audit Committee has discussed with the independent registered public accounting firm the matters required to be discussed by the applicable requirements of the PCAOB and the SEC. The Audit Committee has also received the written disclosures and the letter from the independent registered public accounting firm required by applicable requirements of the PCAOB regarding the independent accountants’ communications with the Audit Committee concerning independence, and has discussed with the independent registered public accounting firm the accounting firm’s independence. Based on the foregoing, the Audit Committee has recommended to the Board that the audited financial statements be included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2025.

Respectfully submitted,

Michael S. Wyzga (Chairman)

Gary Bridger

Françoise De Craecker

March 20, 2026

Compensation Committee

The Compensation Committee is composed of three directors: Dr. Stewart (chair), Ms. De Craecker and Dr. Bridger. The Compensation Committee met seven times during 2025. The Board has adopted a written Compensation Committee charter that is available to stockholders on our website at http://investors.x4pharma.com/, under “Governance.”

The Compensation Committee acts on behalf of the Board to review, approve or recommend for approval by the Board and oversee our compensation strategy, policies, plans and programs, including:


			•						review and approval of, or review and recommendation to the Board for approval of, the compensation and other terms of employment or service, including salary, bonus and incentive compensation levels, deferred compensation, executive perquisites, equity compensation, severance arrangements and change-in-control benefits, of our Executive Chairman and the other executive officers;


			•						oversight of the evaluation of our senior executives, including determining the nature and frequency of the evaluation and the persons subject to the evaluation, supervising the conduct of the evaluation, and preparing assessments of the senior executives’ performance;


			•						review and approval or review and recommendation to the Board of our incentive-compensation and equity-based plans and approval of any tax-qualified, non-discriminatory employee benefit plans for which stockholder approval is not sought and pursuant to which options or stock may be acquired by our officers, directors, employees or consultants;


			•						administration of our equity compensation plans;


			•						review and recommendation to the Board with respect to director compensation; and


			•						adoption and administration of a compensation recovery policy including, without limitation, a policy designed to comply with any rules or regulations adopted by the SEC and Nasdaq pursuant to Section 10D of the Exchange Act.

Compensation Committee Processes and Procedures

Our Compensation Committee is primarily responsible for determining the compensation for our executive officers. In setting base salaries and bonuses and granting equity incentive awards for our executive officers, including our named executive officers (“NEOs”), our Compensation Committee considers compensation for comparable positions in the market, the historical compensation levels of our executives, individual and corporate performance as compared to our expectations and objectives, our desire to motivate our employees to achieve short- and long-term results that are in the best interests of our stockholders, and a long-term commitment to our company. As part of this process, Dr. Craig, as our Executive Chairman, prepares performance evaluations for the other executive officers and recommends annual salary increases, annual equity awards and cash bonuses to the Compensation Committee, which is ultimately approved by the Compensation Committee. The Compensation Committee also conducts a performance evaluation of Dr. Craig (without him being present) and reviews and approves, or recommends for approval by the Board, the compensation of Dr. Craig, including salary, bonus and incentive compensation levels; deferred compensation; executive perquisites; equity compensation; severance arrangements; change-in-control benefits and/or other forms of executive officer compensation. Dr. Craig may not be present during voting or deliberations on her compensation or evaluation. As necessary, the Compensation Committee consults with the Board as to the achievement of corporate objectives that drive contingent compensation awards.

Our Compensation Committee has the authority to delegate authority to one or more subcommittees as it deems appropriate from time to time under the circumstances. Additionally, our Compensation Committee may delegate to one or more executive officers of the Company the power to grant options or other stock awards pursuant to our equity-based plan to employees of the Company or any subsidiary of the Company who are not directors or executive officers of the Company.

Our Compensation Committee has the authority to engage the services of a consulting firm or other outside advisors to assist it in designing our executive and director compensation programs and in making compensation decisions. We have utilized a compensation consultant, Alpine Rewards, with expertise in the biotechnology market, to help assess director and executive compensation and to help inform our compensation strategy. In 2025, Alpine Rewards did not provide any additional services other than advising on director and executive compensation matters. Alpine Rewards reports directly to our Compensation

Committee. Our Compensation Committee regularly assesses its independence consistent with Nasdaq listing standards and concluded that the engagement of Alpine Rewards did not raise any conflict of interest.

Nominating and Corporate Governance Committee

The Nominating and Corporate Governance Committee is currently composed of one director: Mr. Wyzga. The Nominating and Corporate Governance Committee met once during 2025. The Board has adopted a written Nominating and Corporate Governance Committee charter that is available to our stockholders on our website at http://investors.x4pharma.com/, under “Governance.”

The Nominating and Corporate Governance Committee of the Board is responsible for identifying, reviewing and evaluating candidates to serve as directors of the Company (consistent with criteria approved by the Board), reviewing and evaluating incumbent directors, recommending to the Board candidates for election to the Board, making recommendations to the Board regarding the membership of the committees of the Board (including with respect to making changes or rotation of members, the creation of additional Board committees, or changes in Committee charters), overseeing an annual self-assessment of the Board, overseeing succession planning for senior executives of the Company, and developing and recommending to the Board a set of corporate governance principles for the Company.

The Nominating and Corporate Governance Committee believes that candidates for director should have certain minimum qualifications, including a reputation for integrity, honesty and adherence to high ethical standards; demonstrated business acumen, experience and the ability to exercise sound judgments in matters that relate to the current and long-term objectives of the Company and a willingness and ability to contribute positively to the decision-making process of the Company; a commitment to understand the Company and its industry and to regularly attend and participate in meetings of the Board and its committees; the interest and ability to understand the sometimes conflicting interests of the various constituencies of the Company, which include stockholders, employees, customers, governmental units, creditors and the general public, and to act in the interests of all stockholders; and the ability to serve for at least three years before reaching the age of 75. The Nominating and Corporate Governance Committee also believes that candidates for director should not have, nor appear to have, a conflict of interest that would impair the candidate’s ability to represent the interests of all the Company’s stockholders and to fulfill the responsibilities of a director. The Nominating and Corporate Governance Committee retains the right to modify these qualifications from time to time. Candidates for director nominees are reviewed in the context of the current composition of the Board, the operating requirements of the Company and the long-term interests of stockholders, and the Nominating and Corporate Governance Committee has direct input from the Executive Chairman and Lead Independent Director.

Our Nominating and Corporate Governance Committee has not established any specific minimum qualifications for membership on our board of directors. Rather, the Committee will generally consider all relevant factors, which may include independence, experience, diversity, leadership qualities and strength of character. The Committee uses its available network of contacts when compiling a list of potential director candidates and may also engage outside consultants when appropriate.

The Nominating and Corporate Governance Committee will consider director candidates recommended by stockholders and other parties. The Nominating and Corporate Governance Committee does not intend to alter the manner in which it evaluates candidates, including the minimum criteria set forth above, based on whether or not the candidate was recommended by a stockholder or other parties. Stockholders or other parties who wish to recommend individuals for consideration by the Nominating and Corporate Governance Committee to become nominees for election to the Board may do so by delivering a written recommendation to the Nominating and Corporate Governance Committee at the following address: c/o X4 Pharmaceuticals, Inc., 61 North Beacon Street, 4th Floor, Boston, Massachusetts 02134 at least 120 days prior to the anniversary date of the mailing of our Proxy Statement for the last Annual Meeting of Stockholders. Submissions must include the full name of the proposed nominee, a description of the proposed nominee’s business experience for at least the previous five years, complete biographical information, a description of the proposed nominee’s qualifications as a director and a representation that the nominating stockholder is a beneficial or record holder of our common stock and has been a holder for at least one year. Any such submission must be accompanied by the written consent of the proposed nominee to be named as a nominee and to serve as a director if elected.

The Nominating and Corporate Governance Committee appreciates the value of thoughtful Board refreshment, and regularly identifies and considers qualities, skills and other director attributes that would enhance the composition of the Board. In the case of incumbent directors whose terms of office are set to expire, the Committee reviews these directors’ overall service to the Company during their terms, including the number of meetings attended, level of participation, quality of performance and any other relationships and transactions that might impair the directors’ independence. The Nominating and Corporate Governance Committee also takes into account the results of the Board’s self-evaluation, conducted annually on a group and individual basis. In the case of new director candidates, the Nominating and Corporate Governance Committee also assesses whether the nominee is independent under Nasdaq listing standards and applicable SEC rules and regulations. The

Nominating and Corporate Governance Committee then uses its network of contacts to compile a list of potential candidates, but may also engage, if it deems appropriate, a professional search firm. The Nominating and Corporate Governance Committee conducts any appropriate and necessary inquiries into the backgrounds and qualifications of possible candidates after considering the function and needs of the Board. The Nominating and Corporate Governance Committee meets to discuss and consider the candidates’ qualifications and then selects a nominee for recommendation to the Board.

STOCKHOLDER COMMUNICATIONS WITH THE BOARD OF DIRECTORS

Stockholders and other interested parties may communicate with our Board or a particular director by sending a letter addressed to the Board or a particular director to our Corporate Secretary at 61 North Beacon Street, 4th Floor, Boston, Massachusetts 02134. These communications will be reviewed by one or more employees of the Company designated by the Board, who will determine whether the communication should be presented to the Board.

Communications will be distributed to the Board, or to any individual director or directors, as appropriate, depending on the facts and circumstances outlined in the communications. Items that are unrelated to the duties and responsibilities of our Board of Directors may be excluded, such as:


			•						junk mail and mass mailings;


			•						resumes and other forms of job inquiries;


			•						surveys; and


			•						solicitations or advertisements.

In addition, any material that is unduly hostile, threatening, or illegal in nature may be excluded, in which case it will be made available to any outside director upon request.

CODE OF ETHICS

We have adopted a Code of Business Conduct and Ethics that applies to all of our officers, directors and employees. The Code of Business Conduct and Ethics is available on our website at https://www.x4pharma.com/compliance-ethics/. If the Company makes any substantive amendments to the Code of Business Conduct and Ethics or grants any waiver from a provision of the Code of Business Conduct and Ethics to any executive officer or director, the Company will promptly disclose the nature of the amendment or waiver on its website to the extent required by SEC rules and Nasdaq listing standards.

INSIDER TRADING POLICY

Our Board has adopted an insider trading policy, which governs the purchase, sale and/or other dispositions of our securities, that applies to all of our directors, officers, and employees that we believe are reasonably designed to promote compliance with insider trading laws, rules and regulations, and listing standards applicable to us. Our insider trading policy also prohibits these individuals from engaging in hedging or monetization transactions with respect to our securities, including through the use of financial instruments such as prepaid variable forwards, equity swaps, collars, and exchange funds. In addition, our insider trading policy prohibits trading in derivative securities related to our securities, which include publicly traded call and put options, engaging in short selling of our common stock, purchasing our common stock on margin or holding it in a margin account and pledging our shares as collateral for a loan. It is the Company’s policy to comply with applicable insider trading laws, rules, and regulations, and any exchange listing standards when engaging in transactions in Company securities. A copy of our stock trading policy is filed as Exhibit 19.1 to our Annual Report on Form 10-K for the year ended December 31, 2025.

INCENTIVE COMPENSATION RECOUPMENT POLICY

Our board of directors adopted an Incentive Compensation Recoupment Policy effective as of October 2, 2023 (the “Incentive Compensation Recoupment Policy”), in compliance with the Nasdaq listing rules, which requires recovery from executive officers of incentive-based compensation that is earned, granted or vested based on the achievement of a financial reporting measure in the event of a required accounting restatement of previously issued financial statements. The recoverable compensation includes any compensation received after the effective date of the Incentive Compensation Recoupment Policy and in the three-year fiscal period preceding the date we were required to prepare the accounting restatement that is in excess of the amount that would have been earned, paid or vested had it been calculated based on the restated financial statements. Recovery is required regardless of fault or a covered officer’s role in the financial reporting process. The Incentive Compensation Recoupment Policy has been filed as Exhibit 97.1 to our Annual Report on Form 10-K

for the year ended December 31, 2025. At no time during or after the year ended December 31, 2025, was the Company required to prepare an accounting restatement that required recovery of erroneously awarded compensation pursuant to the Incentive Compensation Recoupment Policy, nor was there, on December 31, 2025, an outstanding balance of erroneously awarded compensation to be recovered from the application of the policy to a prior restatement.

PROPOSAL 2

RATIFICATION OF SELECTION OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

The Audit Committee of the Board has selected PricewaterhouseCoopers LLP (“PwC”) as our independent registered public accounting firm for the year ending December 31, 2026. PwC has served as our independent auditor since 2016. Representatives of PwC are expected to be present at the Annual Meeting. They will have an opportunity to make a statement if they so desire and are expected to be available to respond to appropriate questions.

Neither our Bylaws nor other governing documents or law require stockholder ratification of the selection of PwC as our independent registered public accounting firm. However, we are submitting the selection of PwC to the stockholders for ratification as a matter of good corporate practice. If the stockholders fail to ratify the selection, the Audit Committee will reconsider whether or not to retain that firm. Even if the selection is ratified, the Audit Committee in its discretion may direct the selection of different independent auditors at any time during the year if it determines that such a change would be in our best interests and the best interests of our stockholders.

INDEPENDENT AUDITOR FEES AND SERVICES

The following table represents aggregate fees billed or expected to be billed to us for the fiscal years ended December 31, 2025 and December 31, 2024 by PwC. All services associated with such fees were pre-approved by the Audit Committee in accordance with the pre-approval policy and procedures described below.



	Year Ended December 31,
	2025		2024
Audit Fees (1)	$	1,235,000	$	1,130,000
Audit-related Fees	—		—
Tax Fees	—		—
All Other Fees (2)	2,125		2,125
Total Fees	$	1,237,125	$	1,132,125


(1)			Consists of fees billed for professional services provided to us in connection with the annual audit of our consolidated financial statements, the review of our quarterly condensed consolidated financial statements, as well as audit services that are normally provided by an independent registered public accounting firm in connection with statutory and regulatory filings or engagements for those fiscal years, such as statutory audits. Included in 2025 and 2024 Audit Fees are fees of $250,000 and $220,000, respectively, in connection with the filing of registration statements and issuance of comfort letters.


(2)			Consists of subscription fees paid for access to online accounting research software applications and data.

PRE-APPROVAL POLICIES AND PROCEDURES

The Audit Committee has adopted a policy and procedures for the pre-approval of audit and non-audit services rendered by our independent registered public accounting firm, PwC. Prior to engagement of an independent registered public accounting firm for the next year’s audit, management will submit an aggregate of services expected to be rendered during that year for each of four categories of services (audit services, audit-related services, tax services and other fees) to the Audit Committee for approval. Prior to engagement, the Audit Committee pre-approves these services by category of service. The fees are budgeted, and the Audit Committee requires our independent registered public accounting firm and management to report actual fees versus budget periodically throughout the year by category of service. During the year, circumstances may arise when it may become necessary to engage our independent registered public accounting firm for additional services not contemplated in the original pre-approval. In those instances, the Audit Committee requires specific pre-approval before engaging our independent registered public accounting firm. The pre-approval of services may be delegated to one or more of the Audit Committee’s members, but the decision must be reported to the full Audit Committee at its next scheduled meeting.

THE BOARD OF DIRECTORS RECOMMENDS

A VOTE “FOR” PROPOSAL 2.

PROPOSAL 3

APPROVAL OF THE SECOND AMENDED AND RESTATED 2017 EQUITY INCENTIVE PLAN, INCREASING THE NUMBER OF SHARES AVAILABLE FOR ISSUANCE UNDER THE PLAN

The X4 Pharmaceuticals, Inc. Amended and Restated 2017 Equity Incentive Plan (the “2017 Plan”) was originally approved by the Board and our stockholders on June 10, 2020. On March 17, 2026, our Board approved a second amendment and restatement of the 2017 Plan (the “A&R 2017 Plan”), subject to stockholder approval, approving an increase in the number of shares available for issuance under the A&R 2017 Plan by 1,500,000 (the “Share Increase”).

Our Board has determined that it is in the best interests of X4 and its stockholders to approve this proposal, and recommends that stockholders vote in favor of this proposal at the Annual Meeting. Stockholder approval of this proposal requires the affirmative vote of a majority of the votes cast by the holders of shares present in person or by proxy and entitled to vote at the Annual Meeting.

If our stockholders approve this proposal, the A&R 2017 Plan will become effective as of the date of stockholder approval. If our stockholders do not approve this proposal, the A&R 2017 Plan will not become effective and the 2017 Plan will continue to be administered in its current form. The Company has filed with the SEC a registration statement on Form S-8 covering the new shares reserved for issuance under the A&R 2017 Plan.

Background

As of March 1, 2026, 515,292 shares remained available for grant under the 2017 Plan, excluding the award of restricted stock units (“RSUs”) to certain NEOs approved in August 2025 and effective only upon stockholder approval of the A&R 2017 Plan and the award of stock options to our independent directors, each of which are discussed below and are subject to stockholder approval of this Proposal 3 (we refer to these as the “Contingent Awards” as described below). The table below includes aggregate information regarding the number of shares subject to outstanding equity awards (other than the Contingent Awards) granted under the 2017 Plan, as of March 1, 2026; the number of shares available for future awards under the 2017 Plan (not taking into account the Contingent Awards), as of March 1, 2026; and the proposed number of shares that would be available for issuance of future awards under the A&R 2017 Plan if this proposal is approved by our stockholders, which additional shares would be used to fund the Contingent Awards as well as any other future awards. The table below does not include the future effect, in 2027, of the evergreen provisions of the 2017 Plan, which will remain in effect whether or not stockholders approve the A&R 2017 Plan.


	Number of shares	As a percentage of stock outstanding
Total shares subject to outstanding awards (1)	3,347,711	3.7%
Total shares available for future awards (2)	515,292	0.6%
Proposed additional shares to be available for future awards under the A&R 2017 Plan (3)	1,500,000	1.7%
Total shares outstanding under existing equity awards and proposed to be available for issuance under the A&R 2017 Plan (3)	5,363,003	5.9%

(1) Includes awards granted under the 2017 Plan. Does not take into account the Share Increase.

(2) Includes shares available for future awards under the 2017 Plan. Does not include the future effect, in 2027, of the evergreen provision of the 2017 Plan.

(3) Does not include the future effect, in 2027, of the evergreen provision of the 2017 Plan. Share counting provisions, including adjustments to the number of shares available under the A&R 2017 Plan, are described below under “Authorized Shares” and “Certain Transactions; Certain Adjustments”.

In connection with the commencement of their employment in August 2025, we have approved equity awards in the form of time-based restricted stock units representing a total of 773,016 shares to Dr. Craig, Mr. Volpone, and Mr. Kirske (in the amounts of 289,881 RSUs, 289,881 RSUs, and 193,254 RSUs, respectively), all of which will be awarded only if stockholders approve this Proposal 3 (the “Contingent RSU Awards”). In addition, in connection with the adoption of a new Non-Employee Director Compensation Policy adopted on December 12, 2025 and effective January 1, 2026, we have granted 110,000 stock options to each of our independent non-employee directors effective January 1, 2026, each of which is contingent upon stockholder approval of this Proposal 3 (the “Contingent Stock Option Awards” and together with the Contingent RSU Awards, the “Contingent Awards”). The Non-Employee Director Policy is further described below under “Narrative to Director Compensation Table – Non-Employee Director Compensation Policy”. For the avoidance of doubt, the Contingent RSU Awards have not yet been granted and will only be awarded if this Proposal 3 is approved, whereas the

Contingent Stock Option Awards have been granted contingent upon approval of this Proposal 3 and will be cancelled if this Proposal 3 is not approved.

The other material features of the A&R 2017 Plan remain the same as under the terms of the 2017 Plan previously approved by our stockholders and are described below.

Material Features of the A&R 2017 Plan

The material terms of the A&R 2017 Plan are summarized below. The following description of the A&R 2017 Plan is a summary only and is qualified in its entirety by reference to the complete text of the A&R 2017 Plan. Stockholders are urged to read the actual text of the A&R 2017 Plan in its entirety, a copy of which is attached to this proxy statement as Annex A.

Administration

The A&R 2017 Plan will continue to be administered by our Board. Our Board has the authority to, among other things, interpret the A&R 2017 Plan, determine eligibility for and grant awards, determine, modify or waive the terms and conditions of any awards, determine the form of settlement of awards (whether in cash, shares of our common stock or other property), and do all things necessary or appropriate to carry out the purposes of the A&R 2017 Plan. Our Board’s determinations under the A&R 2017 Plan are conclusive and binding. Our Board may delegate its authority under the A&R 2017 Plan to one or more committees of the Board or certain officers of the Company and has, in fact, delegated such authority to the Compensation Committee. References in this summary to our Board refer to our Board and its applicable delegates, including the Compensation Committee.

Eligibility

Our employees, officers, directors, consultants and advisors are eligible to participate in the A&R 2017 Plan. As of March 1, 2026, we estimate that approximately 40 employees (excluding officers), three officers, four directors, and approximately 20 consultants and advisors were eligible to participate. Incentive stock options may be granted under the A&R 2017 Plan only to our employees, including our executive officers.

Authorized Shares

Subject to adjustment, as described below, the maximum number of shares of our common stock that may be delivered in satisfaction of awards under the 2017 Plan as of March 1, 2026 was equal to the sum of (1) 19,071 shares, plus (2) such additional number of shares up to 7,605 shares as is equal to the sum of (a) the number of shares reserved for issuance under the Company’s 2011 Stock Incentive Plan, as amended, and the Company’s 2010 Special Stock Incentive Plan, as amended (the “Prior Plans”), and (b) the number of shares subject to awards granted under the Prior Plans which expire, terminate or are otherwise surrendered, canceled, forfeited or repurchased, plus (3) an annual increase to be added on the first day of each fiscal year, beginning with the fiscal year ending December 31, 2018 and continuing for each fiscal year until, and including, the fiscal year ending December 31, 2027, equal to the least of (i) 4% of the outstanding shares on such date and (ii) an amount determined by the Board. A total of 515,292 shares remained available for grant as of March 1, 2026, not including the Contingent Awards, which are subject to stockholder approval of the A&R 2017 Plan. If this proposal is approved by stockholders, an additional 1,500,000 shares will become available under the A&R 2017 Plan, subject to adjustment, as described below, and excluding the future effect of the evergreen provision. In addition to the 1,500,000 shares that will be available for future grants if this proposal is approved, any shares subject to outstanding awards under the 2017 Plan that (1) expire, terminate, or are surrendered or are canceled without having been fully exercised, or are forfeited in whole or in part (including as the result of shares of common stock subject to such award being repurchased by us) or (2) are not issued will again be available for issuance under the A&R 2017 Plan. Further, if any shares are delivered (by actual delivery, attestation, or net exercise) to us by a participant to (i) purchase shares of common stock upon the exercise of an award or (ii) satisfy tax withholding obligations with respect to awards, then such shares will be added back to the number of shares available for issuance under the A&R 2017 Plan.

Subject to adjustment, as described below, no more than 104,874 shares of our common stock may be delivered in satisfaction of incentive stock options (“ISOs”) awarded under the A&R 2017 Plan.

The shares of our common stock to be issued under the A&R 2017 Plan may be authorized but unissued shares of our common stock or treasury shares. The closing price of our common stock as reported on Nasdaq on March 1, 2026 was $3.44 per share.

Types of Awards

The A&R 2017 Plan provides for awards of stock options, stock appreciation rights (“SARs”), restricted stock, restricted stock units, and other stock-based awards convertible into or otherwise based on shares of our common stock.

Stock options and SARs. The exercise price of a stock option, and the base value against which a SAR, is to be measured, may not be less than the fair market value (or, in the case of an ISO granted to a ten percent stockholder, 110% of the fair market value) of shares of our common stock on the date of grant. Our Board will determine the time or times at which stock options or SARs become exercisable and the terms on which such awards remain exercisable, except no stock option or SAR may have a term in excess of ten years.

Restricted stock. A restricted stock award is an award of shares of our common stock subject to forfeiture restrictions. Restricted stock awards are subject to our right to repurchase all or part of such shares at their issue price or other stated or formula price (or to require forfeiture of such shares if issued at no cost) from the recipient in the event that conditions specified by the Board in the applicable award are not satisfied prior to the end of the applicable restriction period or periods established by the Board for such award. Dividend rights may be provided in connection with a restricted stock award. Our Board will determine the terms and conditions of a restricted stock award, including the conditions for vesting and repurchase (or forfeiture) and the issue price, if any.

Restricted stock units. A restricted stock unit award is an award denominated in shares of our common stock that entitles the participant to receive shares of our common stock or cash measured by the value of the shares of our common stock in the future. The delivery of shares of our common stock or cash under a restricted stock unit may be subject to the satisfaction of performance conditions or other vesting conditions. Dividend equivalent rights may be provided in connection with a restricted stock unit award. Our Board will determine the terms and conditions of a restricted stock unit award, including the conditions for vesting and repurchase (or forfeiture) and the issue price, if any.

Other stock-based awards. Other stock-based awards are awards that are valued in whole or in part by reference to, or are otherwise based on, shares of our common stock or other property. Our Board will determine the terms and conditions of other stock-based awards, including any purchase price applicable thereto.

Limitation on Repricing of Stock Options and SARs

Unless such action is approved by the Company’s stockholders, the Company may not: (1) amend any outstanding stock option or SAR granted under the A&R 2017 Plan to provide an exercise price per share that is lower than the then-current exercise price per share of such outstanding stock option or SAR, (2) cancel any outstanding option or SAR (whether or not granted under the A&R 2017 Plan) and grant in substitution therefor new awards under the A&R 2017 Plan (other than substitute awards granted in connection with a merger, consolidation or other acquisition) covering the same or a different number of shares and having an exercise price per share lower than the then-current exercise price per share of the cancelled option or SAR, (3) cancel in exchange for a cash payment any outstanding option or SAR with an exercise price per share above the then-current fair market value of our common stock or (4) take any other action under the Plan that constitutes a “repricing” within the meaning of the rules of Nasdaq.

Vesting; Change in Status

Our Board has the authority to determine the vesting schedule applicable to each award, and to accelerate the vesting or exercisability of any award. Our Board also has the authority to determine the effect of a change in employment or other status on an award.

Non-Transferability of Awards

Awards under the Second Amended and Restated 2017 Equity Plan may not be transferred, other than by will or the laws of descent and distribution, or other than in the case of ISOs, pursuant to a qualified domestic relations order, unless otherwise provided by our Board.

Clawback

Awards will be subject to recoupment in accordance with any clawback policy adopted by the Company, including our Incentive Compensation Recoupment Policy (or any successor clawback policy adopted by the Company).

Certain Transactions; Certain Adjustments

In the event of (1) a merger or consolidation as a result of which all of our common stock is converted into or exchanged for the right to receive cash, securities or other property or is cancelled, (2) any transfer or disposition of all of our common stock, or (3) our dissolution or liquidation (any of the foregoing, a “covered transaction”), our Board may, with respect to awards (other than restricted stock awards), (a) provide that such awards will be assumed, or substantially equivalent awards will be substituted, by the acquiring or succeeding corporation (or an affiliate thereof), (b) upon written notice to a participant, provide that all of the participant’s unvested awards will be forfeited immediately prior to the consummation of such covered transaction and/or unexercised awards will terminate immediately prior to the consummation of such covered transaction unless exercised by the participant (to the extent then exercisable) within a specified period following the date of

such notice, (c) provide that outstanding awards will become exercisable, realizable or deliverable, or restrictions applicable to an award will lapse, in whole or in part prior to or upon such covered transaction, (d) in the event of a covered transaction under the terms of which holders of our common stock will receive upon consummation thereof a cash payment for each share surrendered in the covered transaction (the “acquisition price”), make or provide for a cash payment to participants with respect to each award held by a participant equal to (i) the number of shares of our common stock subject to the vested portion of the award (after giving effect to any acceleration of vesting that occurs upon or immediately prior to such covered transaction) multiplied by (ii) the excess, if any, of (A) the acquisition price over (B) the exercise, measurement or purchase price of such award and any applicable tax withholdings, in exchange for the termination of such award, (e) provide that, in connection with a liquidation or dissolution of the Company, awards will convert into the right to receive liquidation proceeds (if applicable, net of the exercise, measurement or purchase price thereof and any applicable tax withholdings) and (f) any combination of the foregoing.

Upon the occurrence of a covered transaction other than a liquidation or dissolution of the Company, the repurchase and other rights of the Company with respect to outstanding restricted stock awards will inure to the benefit of the Company’s successor and will, unless the Board determines otherwise, apply to the cash, securities or other property which our common stock was converted into or exchanged for pursuant to such covered transaction in the same manner and to the same extent as they applied to such restricted stock award. The Board may provide for termination or deemed satisfaction of such repurchase or other rights under the instrument evidencing any restricted stock award or any other agreement between a participant and the Company, either initially or by amendment. Upon the occurrence of a covered transaction involving the liquidation or dissolution of the Company, except to the extent specifically provided to the contrary in the instrument evidencing any restricted stock award or any other agreement between a participant and the Company, all restrictions and conditions on all restricted stock awards then outstanding will automatically be deemed terminated or satisfied.

In the event of any stock split, reverse stock split, stock dividend, recapitalization, combination of shares, reclassification of shares, spin-off or other similar change in capitalization or event, or any dividend or distribution to holders of our common stock other than an ordinary cash dividend, (1) the number and class of securities available under the A&R 2017 Plan, (2) the share counting rules of the A&R 2017 Plan, (3) the number and class of securities and exercise price per share of each outstanding stock option, (4) the share and per-share provisions and the measurement price of each outstanding SAR, (5) the number of shares subject to and the repurchase price per share subject to each outstanding restricted stock and restricted stock unit award and (6) the share and per-share-related provisions and the purchase price, if any, of each outstanding other stock-based award, will be equitably adjusted by the Company (or substituted awards may be made, if applicable) in the manner determined by the Board.

Amendment; Termination

Our Board may amend the A&R 2017 Plan or outstanding awards, or terminate the A&R 2017 Plan as to future grants of awards, except that our Board will not be able to alter the terms of an award if it would affect materially and adversely a participant’s rights under the award without the participant’s consent. Stockholder approval will be required for any amendment to the A&R 2017 Plan to the extent such approval is required by law, including applicable stock exchange requirements.

Certain U.S. Federal Income Tax Consequences

The following is a summary of the principal U.S. federal income tax consequences to participants and us with respect to awards granted under the A&R 2017 Plan. This summary is not intended to be exhaustive and does not discuss the income tax laws of any local, state or foreign jurisdiction in which a participant may reside. The information is based upon current U.S. federal income tax rules and therefore is subject to change when those rules change. Because the tax consequences to any participant may depend on his or her personal circumstances, each participant should consult the participant’s tax adviser regarding the federal, state, local and other tax consequences of the grant or exercise of an award or the disposition of shares acquired under the A&R 2017 Plan. The A&R 2017 Plan is not qualified under the provisions of Section 401(a) of the Code and is not subject to any of the provisions of the Employee Retirement Income Security Act of 1974, as amended. Our ability to realize the benefit of any tax deductions described below depends on our generation of taxable income as well as the requirement of reasonableness and the satisfaction of our tax reporting obligations.

Stock Options (other than ISOs)

In general, a participant has no taxable income upon the grant of a stock option that is not intended to be an ISO (an “NSO”) but realizes ordinary income in connection with the exercise of the NSO in an amount equal to the excess (at the time of exercise) of the fair market value of the shares acquired upon exercise over the exercise price. Upon a subsequent sale or exchange of the shares, any recognized gain or loss is treated as a capital gain or loss for which the Company is not entitled to a deduction.

Subject to the requirement of reasonableness, the provisions of Section 162(m) of the Code, and the satisfaction of a tax reporting obligation, we will generally be entitled to a tax deduction equal to the taxable ordinary income realized by the participant.

ISOs

A participant generally is not subject to ordinary income tax upon the grant or exercise of an ISO. If the participant holds a share received upon exercise of an ISO for more than two years from the date the stock option was granted and more than one year from the date the stock option was exercised, which is referred to as the required holding period, the difference, if any, between the amount realized on a sale or other taxable disposition of that share and the participant’s tax basis in that share will be long-term capital gain or loss.

If, however, a participant disposes of a share acquired upon exercise of an ISO before the end of the required holding period, which is referred to as a disqualifying disposition, the participant generally will recognize ordinary income in the year of the disqualifying disposition equal to the excess, if any, of the fair market value of the share on the date of exercise of the stock option over the exercise price. However, if the sales proceeds are less than the fair market value of the share on the date of exercise of the stock option, the amount of ordinary income recognized by the participant will not exceed the gain, if any, realized on the sale. If the amount realized on a disqualifying disposition exceeds the fair market value of the share on the date of exercise of the stock option, that excess will be short-term or long-term capital gain, depending on whether the holding period for the share exceeds one year.

For purposes of the alternative minimum tax, the amount by which the fair market value of a share of stock acquired upon exercise of an ISO exceeds the exercise price of the stock option generally will be an adjustment included in the participant’s alternative minimum taxable income for the year in which the stock option is exercised. If, however, there is a disqualifying disposition of the share in the year in which the stock option is exercised, there will be no adjustment for alternative minimum tax purposes with respect to that share. In computing alternative minimum taxable income, the tax basis of a share acquired upon exercise of an ISO is increased by the amount of the adjustment taken into account with respect to that share for alternative minimum tax purposes in the year the stock option is exercised.

We are not allowed a tax deduction with respect to the grant or exercise of an ISO or the disposition of a share acquired upon exercise of an ISO after the required holding period. If there is a disqualifying disposition of a share, however, we will generally be entitled to a tax deduction equal to the taxable ordinary income realized by the participant, subject to the requirement of reasonableness, the provisions of Section 162(m) of the Code, and provided that either the employee includes that amount in income or we timely satisfy our reporting requirements with respect to that amount.

SARs

The grant of a SAR does not itself result in taxable income, nor does taxable income result merely because a SAR becomes exercisable. In general, a participant who exercises a SAR for shares of stock or receives payment in cancellation of a SAR will have ordinary income equal to the amount of any cash and the fair market value of any stock received. A corresponding deduction is generally available to the Company, subject to the requirement of reasonableness, the provisions of Section 162(m) of the Code, and the satisfaction of a tax reporting obligation.

Restricted Stock Awards

A participant who is awarded or purchases shares subject to a substantial risk of forfeiture generally does not have income until the risk of forfeiture lapses. When the risk of forfeiture lapses, the participant has ordinary income equal to the excess of the fair market value of the shares at that time over the purchase price, if any, and a corresponding deduction is generally available to the Company, subject to the requirement of reasonableness, the provisions of Section 162(m) of the Code, and the satisfaction of a tax reporting obligation. However, a participant may make an election under Section 83(b) of the Code to be taxed on restricted stock when it is acquired rather than later, when the substantial risk of forfeiture lapses. A participant who makes an effective 83(b) election will realize ordinary income equal to the fair market value of the shares as of the time of acquisition less any price paid for the shares. A corresponding deduction will generally be available to the Company, subject to the requirement of reasonableness, the provisions of Section 162(m) of the Code, and the satisfaction of a tax reporting obligation. If a participant makes an effective 83(b) election, no additional income results by reason of the lapsing of the restrictions.

For purposes of determining capital gain or loss on a sale of shares awarded under the A&R 2017 Plan, the holding period in the shares begins when the participant recognizes taxable income with respect to the transfer. The participant’s tax basis in the shares equals the amount paid for the shares plus any income realized with respect to the transfer. However, if a participant makes an effective 83(b) election and later forfeits the shares, the tax loss realized as a result of the forfeiture is limited to the excess of what the participant paid for the shares (if anything) over the amount (if any) realized in connection with the forfeiture.

Restricted Stock Units

Generally, the recipient of a restricted stock unit award structured to comply with the requirements of Section 409A of the Code or an exception to Section 409A of the Code will recognize ordinary income at the time the stock is delivered equal to the excess, if any, of the fair market value of the stock received over any amount paid by the recipient in exchange for the stock. To comply with the requirements of Section 409A of the Code, the stock subject to a restricted stock unit award may generally only be delivered upon one of the following events: a fixed calendar date (or dates), separation from service, death, disability or a change in control. If delivery occurs on another date, unless the restricted stock unit award otherwise complies with or qualifies for an exception to the requirements of Section 409A of the Code (including delivery upon achievement of a performance goal), in addition to the tax treatment described above, the recipient will owe an additional 20% federal tax and interest on any taxes owed.

The recipient’s basis for the determination of gain or loss upon the subsequent disposition of shares acquired from a restricted stock unit award will be the amount paid for such shares plus any ordinary income recognized when the stock is delivered.

Section 162(m) Limitations

Section 162(m) of the Code generally disallows a tax deduction to public companies for compensation in excess of $1 million paid to each of the company’s chief executive officer, chief financial officer, and the three most highly compensated executive officers (other than the chief executive officer and chief financial officer) and any person who was part of that group for any other year beginning after December 31, 2016. As a result, it is expected that generally all compensation in excess of $1 million paid to any of the executives described above will not be deductible by us. The Board may grant awards under the A&R 2017 Plan or otherwise that are or may become non-deductible when it believes doing so is in the best interests of the Company and our stockholders.

New Plan Benefits

The following table sets forth certain information regarding future benefits under the A&R 2017 Plan:


Name and Position	Number of Shares
Adam R. Craig, M.D., Ph.D., M.B.A.
Executive Chairman		289,881	(1)
Paula Ragan, Ph.D.
Former President and Chief Executive Officer		—	(2)
John Volpone, M.B.A.
President and Chief Operating Officer		289,881	(1)
David Kirske
Chief Financial Officer, Treasurer and Corporate Secretary		193,254	(1)
All current executive officers as a group		773,016	(1)
All current directors who are not executive officers as a group		440,000	(3)
All current employees, including all current officers who are not executive officers		—	(1)

(1) Awards granted under the A&R 2017 Plan to our executive officers and other employees are discretionary and are not subject to set benefits or amounts under the terms of the A&R 2017 Plan. However, in August 2025, our Board conditionally approved the Contingent RSU Awards for Dr. Craig and for Messrs. Volpone and Kirske under the A&R 2017 Plan, subject to stockholder approval of this Proposal 3, and the maximum number of shares subject to each award is indicated in this table.

(2) Paula Ragan, Ph.D., our former President and Chief Executive Officer, will not be eligible to receive future benefits under the A&R 2017 Plan.

(3) In January 2026, our Board conditionally approved the Contingent Stock Option Awards for our independent directors, subject to stockholder approval of this Proposal 3.

2017 Plan Benefits

The following table presents certain information with respect to awards that have been granted (even if not currently outstanding) under the 2017 Plan as of March 1, 2026:


Name and Position			Cumulative Number of Shares Subject to Awards Under the 2017 Plan
Adam R. Craig, M.D., Ph.D., M.B.A.
Executive Chairman			—
Paula Ragan, Ph.D.
Former President and Chief Executive Officer			141,820
John Volpone, M.B.A.
President and Chief Operating Officer			—
David Kirske
Chief Financial Officer, Treasurer and Corporate Secretary			—
All current executive officers as a group			—
All current directors who are not executive officers as a group			469,751
Each nominee for election as a director:
Gary J. Bridger, Ph.D.			116,264
Françoise De Craecker			115,130
Murray W. Stewart, M.D.			123,093
Each associate of any current executive officers, current directors or director nominees			—
Each other person who received or is to receive 5% of awards			—
All current employees, including all current officers who are not executive officers, as a group			3,349,043

Vote Required

The affirmative vote of a majority of the votes cast by the holders of shares present in person or by proxy and entitled to vote at the Annual Meeting will be required to approve Proposal 3.

THE BOARD OF DIRECTORS RECOMMENDS A VOTE “FOR” PROPOSAL 3.

PROPOSAL 4

NON-BINDING ADVISORY VOTE ON NAMED EXECUTIVE OFFICER COMPENSATION

In accordance with the rules of the SEC and pursuant to the Dodd-Frank Act, we are providing our stockholders with an opportunity to make a non-binding advisory vote on the compensation of our NEOs, as disclosed in this Proxy Statement.

This non-binding advisory vote is commonly known as a “say-on-pay” vote and provides our stockholders with the opportunity to express their views on our executive compensation for our NEOs for fiscal year 2025.

We urge stockholders to read the “Executive Compensation” section of this Proxy Statement, which discusses our executive compensation policies and procedures and contains tabular information and narrative discussion about our executive compensation policies and procedures and the compensation of our NEOs.

Advisory Vote and Board Recommendation

We request stockholder approval, on a non-binding and advisory basis, of the compensation of our NEOs as disclosed in this Proxy Statement pursuant to the SEC’s compensation disclosure rules (which disclosure includes the compensation tables and narrative disclosures that accompany the compensation tables within the Executive Compensation section of this Proxy Statement). This vote is not intended to address any specific element of compensation, but rather the overall compensation of our NEOs and the compensation philosophy, policies, and practices described in this Proxy Statement. Accordingly, we ask our stockholders to vote “FOR” on the following resolution at the Annual Meeting:

“RESOLVED, that the Company’s stockholders approve, on a non-binding and advisory basis, the compensation of the named executive officers, as disclosed in the Company’s Proxy Statement for the 2026 Annual Meeting of Stockholders pursuant to the compensation disclosure rules of the Securities and Exchange Commission, including the compensation tables and narrative discussions that accompany the compensation tables within the Executive Compensation section of this Proxy Statement.”

The say-on-pay vote is advisory, and therefore not binding on the corporation or our Board of Directors. Although non-binding, our Board of Directors and the Compensation Committee value the opinions of our stockholders, and will carefully review and consider the voting results when making future decisions regarding our executive compensation program.

We are required to hold a say-on-pay vote at least once every three years, and we have determined to hold a say-on-pay vote every year. Unless the Board modifies its policy on the frequency of holding say-on-pay advisory votes, the next say-on-pay vote is expected to occur in 2027.

THE BOARD OF DIRECTORS RECOMMENDS

A VOTE “FOR” PROPOSAL 4.

EXECUTIVE OFFICERS

The following table sets forth information with respect to our executive officers and their ages as of the date of this Proxy Statement. There are no family relationships between any of our executive officers, and there is no arrangement or understanding between any executive officer and any other person pursuant to which the executive officer was selected.

Name

Age

(as of March 20)

Position

Adam R. Craig, M.D., Ph.D., M.B.A.

Executive Chairman and Director

John Volpone, M.B.A.

President and Chief Operating Officer

David Kirske

Chief Financial Officer, Treasurer and Corporate Secretary

Adam R. Craig, M.D., Ph.D. M.B.A. Biographical information for Dr. Craig is presented above under the caption “Class II Directors Continuing In Office Until the 2028 Annual Meeting of Stockholders”.

John Volpone, M.B.A. Mr. Volpone, age 51, has served as our President since August 2025 and Chief Operating Officer since September 2025. He was an independent biopharma consultant providing a variety of regulatory and business strategy consulting services from June 2023 to August 2025. Previously, he served in various roles at CTI BioPharma, including most recently as Executive Vice President and Chief of Staff from September 2021 until June 2023, where he was responsible for overseeing the company’s strategic business initiatives, Senior Vice President, Strategic Operations from September 2020 until September 2021 and Vice President, Strategic Operations - Global Program Lead from September 2017 until September 2020. He is an experienced biopharmaceutical leader in strategic business partnerships, licensing, regulatory engagements and commercialization. Mr. Volpone holds an M.B.A. from Seattle University and a B.Sc. in Biochemistry from the University of Washington.

David Kirske. Mr. Kirske, age 72, has served as our Chief Financial Officer, Treasurer and Corporate Secretary since August 2025. He most recently served as the Chief Financial Officer of Stratus Therapeutics from September 2024 to May 2025, where he was responsible for overseeing the company’s financial management and reporting processes. From August 2023 to September 2024, Mr. Kirske provided financial strategy for biotechnology companies as part of Madrona Financial Consulting. Prior to that, he served as CTI BioPharma’s Executive Vice President, Chief Financial Officer from September 2017 until June 2023, where he was responsible for overseeing the company’s financial management and reporting processes. He is a finance, accounting and investor relations leader for public and emerging growth private companies primarily in the biotechnology industry, as well as in technology and manufacturing. His financial management experience includes overseeing finance, accounting, operations and capitalization in debt and equity. Prior to CTI BioPharma, Mr. Kirske served as Vice President and Chief Financial Officer of Helix BioMedix where he managed all financial and administrative activities. Previously, he was the Treasurer and Corporate Controller for F-5 Networks and Redhook Brewery, where he managed corporate and international entities and was part of the management teams that led and executed each company’s successful initial public offering. Earlier, he held a controllership position at Cray Computer. Mr. Kirske holds a B.A. in Business Administration from the University of Puget Sound.

SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT

The following table sets forth information, to the extent known by us or ascertainable from public filings, with respect to the beneficial ownership of our common stock as of March 1, 2026 by:

•each of our directors and nominees;

•each of our NEOs;

•all of our directors and executive officers as a group; and

•each person, or group of affiliated persons, who is known by us to beneficially own greater-than-5% of our common stock.

The column entitled “Percentage Beneficially Owned” is based on 90,907,011 shares of our common stock outstanding as of March 1, 2026.

Beneficial ownership is determined in accordance with the rules and regulations of the SEC and includes voting or investment power with respect to our common stock. Shares of our common stock subject to options that are currently exercisable or exercisable within 60 days of March 1, 2026 are considered outstanding and beneficially owned by the person holding the options for the purpose of calculating the percentage ownership of that person but not for the purpose of calculating the percentage ownership of any other person. Except as otherwise noted, the persons and entities in this table have sole voting and investing power with respect to all of the shares of our common stock beneficially owned by them, subject to community property laws, where applicable. Except as otherwise indicated in the table below, addresses of named beneficial owners are in care of X4 Pharmaceuticals, Inc., 61 North Beacon Street, 4th Floor, Boston, Massachusetts 02134.



	Beneficial Ownership
Beneficial Owner	Number of Shares		Percent of Total
5% Stockholders
Funds managed by Empery Asset Management, LP (1)		9,096,094		9.99	%
FMR LLC (2)		8,499,100		9.35	%
Morgan Stanley (3)		8,196,489		9.02	%
Entities affiliated with Bain Capital Life Sciences Investors, LLC (4)		7,937,454		8.08	%
Coastland Capital Partners LP (5)		7,046,925		7.27	%
Saturn V Capital Management (6)		6,433,481		7.08	%
Entities affiliated with Perceptive Advisors LLC (7)		5,928,680		6.52	%
Entities affiliated with Growth Equity Opportunities 18 VGE, LLC (8)		5,250,901		5.65	%
Trails Edge Biotechnology Master Fund, LP (9)		5,277,222		5.59	%
Deep Track Biotechnology Master Fund, Ltd. (10)		5,284,621		5.56	%
Named Executive Officers, Directors and Director Nominees
Adam R. Craig, M.D., Ph.D., M.B.A. (11)		86,206		*
John Volpone, M.B.A.		—		*
David Kirske (12)		831,862		*
Paula Ragan, Ph.D. (13)		91,221		*
Gary J. Bridger, Ph.D. (14)		5,483		*
Françoise De Craecker (15)		3,630		*
Murray W. Stewart, M.D. (16)		7,258		*
Michael S. Wyzga (17)		6,941		*
All directors and current executive officers as a group (7 people) (18)		1,032,601		1.13	%


*			Less than one percent.

(1) Based on the Company’s records and a Schedule 13G/A filed by Empery Asset Management, LP (“Empery”) and Ryan Lane on January 15, 2026 reporting ownership as of December 31, 2025. Empery and Mr. Lane have shared voting power and shared dispositive power with respect to (i) 8,951,105 shares of common stock held by Empery Asset Master, LTD (“EAM”), Empery Tax Efficient, LP (“ETE”) and Empery Tax Efficient III, LP (“ETE III,” and collectively with EAM and ETE, the “Empery Funds”) and (ii) 144,989 shares of common stock issuable upon the exercise of pre-funded warrants (“Pre-Funded Warrants”) held by the Empery

Funds. The number of shares set forth under “Shares beneficially owned” above gives effect to beneficial ownership limitations in certain warrants as described below. Without giving effect to such beneficial ownership limitations, Empery and Mr. Lane would have shared voting power and shared dispositive power with respect to (i) 8,951,105 shares of common stock held by the Empery Funds, (ii) 3,760,530 shares of common stock issuable upon the exercise of Pre-Funded Warrants held by EAM, (iii) 1,057,721 shares of common stock issuable upon the exercise of Pre-Funded Warrants held by ETE, (iv) 2,847,148 shares of common stock issuable upon the exercise of Pre-Funded Warrants held by ETE III, (v) 16,660 shares of common stock issuable upon the exercise of warrants to purchase common stock (“Common Warrants”) held by EAM, (vi) 5,025 shares of common stock issuable upon the exercise of Common Warrants held by ETE, (vii) 8,756 shares of common stock issuable upon the exercise of Common Warrants held by ETE III, (viii) 80,169 shares of common stock issuable upon the exercise of Class C warrants (“Class C Warrants”) held by EAM, (ix) 24,454 shares of common stock issuable upon the exercise of Class C Warrants held by ETE and (x) 16,589 shares of common stock issuable upon the exercise of Class C Warrants held by ETE III. The Pre-Funded Warrants held by the Empery Funds contain beneficial ownership blockers that prohibit the exercise thereof if, after giving effect to such exercise, the beneficial ownership of Empery Asset Management, LP, its affiliates and any person whose beneficial ownership would be attributable to it, would exceed 9.99%. The other warrants held by the Empery Funds contain beneficial ownership blockers that prohibit the exercise thereof if, after giving effect to such exercise, the beneficial ownership of Empery Asset Management, LP, its affiliates and any person whose beneficial ownership would be attributable to it, would exceed 4.99%. Empery serves as the investment manager to the Empery Funds. Empery, the authorized agent of each of the Empery Funds, has discretionary authority to vote and dispose of the securities held by such Empery Funds, as applicable, and may be deemed to be the beneficial owner of such securities. Martin Hoe and Ryan Lane, in their capacity as investment managers of Empery, may also be deemed to have investment discretion and voting power over the securities held by the Empery Funds. Each of the Empery Funds, Mr. Hoe and Mr. Lane each disclaim any beneficial ownership of such securities. The address of each of the Empery Funds, Empery, Mr. Hoe and Mr. Lane is c/o Empery Asset Management, LP, One Rockefeller Plaza, Suite 1205, New York City, NY 10020.

(2) Based on a Schedule 13G/A filed by FMR LLC (“FMR”) and Abigail P. Johnson on February 5, 2026 reporting ownership as of October 31, 2025. Each of FMR and Abigail P. Johnson has sole voting power and sole dispositive power with respect to 8,499,100 shares of common stock. Ms. Johnson is a Director, the Chairman and Chief Executive Officer of FMR. Members of the Johnson family, including Ms. Johnson, are the predominant owners, directly or through trusts, of Series B voting common shares of FMR, representing 49% of the voting power of FMR. The Johnson family group and all other Series B shareholders have entered into a shareholders’ voting agreement under which all Series B voting common shares will be voted in accordance with the majority vote of Series B voting common shares. Accordingly, through their ownership of voting common shares and the execution of the shareholders’ voting agreement, members of the Johnson family may be deemed, under the Investment Company Act of 1940, to form a controlling group with respect to FMR. The address of each entity and person listed above is 245 Summer Street, Boston, MA 02210.

(3) Based on a Schedule 13G/A filed by Morgan Stanley and Morgan Stanley Investment Management Inc. (“MSIMI”) on February 12, 2026 reporting ownership as of December 31, 2025. Morgan Stanley and MSIMI have shared voting power and shared dispositive power with respect to 8,196,489 shares of common stock. The address of each entity listed above is 1585 Broadway, New York, NY 10036.

(4) Based on the Company’s records and a Schedule 13G/A filed by Bain Capital Life Sciences Fund, L.P. (“BCLS Fund I”), Bain Capital Life Sciences Fund II, L.P. (“BCLS Fund II”), BCIP Life Sciences Associates, LP (“BCIPLS”), BCLS I Investco, LP (“BCLS I Investco”), BCLS II Investco, LP (“BCLS II Investco”) and BCLS II Equity Opportunities, LP (“BCLS II Equity”, and collectively with BCLS Fund I, BCLS Fund II, BCIPLS, BCLS I Investco and BCLS II Investco, the “Bain Capital Life Sciences Holders”) on February 17, 2026 reporting ownership as of December 31, 2025. Consists of (i) 64,190 shares of common stock held by BCLS Fund II, (ii) 7,817 shares of common stock held by BCIPLS, (iii) 543,642 shares of common stock held by BCLS II Investco, (iv) 7,047,216 shares of common stock issuable upon the exercise of Pre-Funded Warrants held by BCLS II Equity, (v) 214,956 shares of common stock issuable upon the exercise of Common Warrants held by BCLS II Investco, and (vi) 59,633 shares of common stock issuable upon the exercise of Common Warrants held by BLCS I Investco. The number of shares set forth under “Shares beneficially owned” above gives effect to beneficial ownership limitations in certain warrants as described below. Without giving effect to such beneficial ownership limitations, the Bain Capital Life Sciences Holders would own (i) 64,190 shares of common stock held by BCLS Fund II, (ii) 7,817 shares of common stock held by BCIPLS, (iii) 543,642 shares of common stock held by BCLS II Investco, (iv) 7,047,216 shares of common stock issuable upon the exercise of Pre-Funded Warrants held by BCLS II Equity, (v) 214,956 shares of common stock issuable upon the exercise of Common Warrants held by BCLS II Investco, (vi) 59,633 shares of common stock issuable upon the exercise of Common Warrants held by BLCS I Investco, (vii) 68,818 shares of common stock issuable upon the exercise of Class C Warrants by BCLS II Investco, and (viii) 28,696 shares of common stock issuable upon the exercise of Class C warrants held by BCLS I Investco. The Bain Capital Life Sciences Holders are (A) prohibited from exercising Common Warrants or Pre-Funded Warrants if, as a result of such exercise, the Bain Capital Life Sciences Holders would beneficially own more than 9.99% of the total number of shares of common stock then issued and outstanding immediately after giving effect to the exercise and (B) prohibited from exercising Class C Warrants to purchase common stock if, as a result of such exercise, the Bain Capital Life Sciences Holders would beneficially own more than 4.99% of the total number of shares of common stock then issued and outstanding immediately after giving effect to the exercise. Bain Capital Life Sciences Investors, LLC (“BCLSI”), (i) is the general partner of Bain Capital Life Sciences Partners, LP, which is the general partner of BCLS Fund I, (ii) is the manager of Bain Capital Life Sciences Investors II, LLC, which is the general partner of BCLS Fund II and (iii) governs the investment strategy and decision-making process with respect to investments held by BCIPLS. BCLS II Investco (GP), LLC, whose manager is BCLS Fund II, is the general partner of BCLS II Investco, BCLS II Equity Opportunities GP, LLC, whose manager is BCLS Fund II, is the general partner of BCLS II Equity, and BCLS I Investco GP, LLC, whose manager is BCLS Fund I, is the general partner of BCLS I Investco. As a result, BCLSI may be deemed to share voting and dispositive power with respect to the securities held by the Bain Capital Life Sciences Holders. The address of each of the Bain Capital Life Sciences Holders is c/o Bain Capital Life Sciences, 200 Clarendon Street, Boston, MA 02116.

(5) Based on the Company’s records and a Schedule 13G filed by Coastlands Capital LP (“Coastlands”), Coastlands Capital Partners LP (“Coastlands Capital”), Coastlands Capital GP LLC (“Coastlands GP LLC”), Coastlands Capital LLC (“Coastlands GP”, and together with Coastlands, Coastlands Capital and Coastlands GP LLC, the “Coastlands Entities”) and Matthew D. Perry on October 3, 2025 reporting ownership as of October 3, 2025. Coastlands, Coastlands Partnership, Coastlands GP LLC, Coastlands GP and Mr. Perry have shared voting power and shared dispositive power with respect to (i) 999,709 shares of common stock and (ii) 6,047,216 shares of common stock issuable upon the exercise of Pre-Funded Warrants, in each case held by Coastlands Capital. The Pre-Funded Warrants held by Coastlands Capital prohibit the exercise thereof if, after giving effect to such exercise, the beneficial ownership of Coastlands Capital, its affiliates and any person whose beneficial ownership would be attributable to such entities, would exceed 9.99%. Coastlands is the investment adviser to Coastlands Capital and Coastlands GP LLC is the general partner of Coastlands Capital. Coastlands GP is the general partner of Coastlands. Matthew D. Perry is the control person of the Coastlands Entities. The Coastlands Entities and Mr. Perry each disclaim membership in a group. The Coastlands Entities and Mr. Perry also each disclaim beneficial ownership of the shares of common stock except to the extent of such entity or person’s pecuniary interest therein. The address of the Coastlands Entities and Mr. Perry is 601 California St., Suite 1210, San Francisco, CA 94108.

(6) Based on a Schedule 13G filed by Saturn V Capital Management LP (“Saturn Capital”) and Xiaoying Tian on February 17, 2026 reporting ownership as of October 24, 2025. Saturn Capital and Ms. Tian have shared voting power and shared dispositive power with respect to 6,433,481 shares of common stock. Saturn Capital acts as the investment manager of certain pooled investment vehicles and managed accounts (collectively the “Saturn Clients”) in which such shares referred to above are held. As a result, Saturn Capital possesses the power to vote and dispose or direct the disposition of all the shares beneficially owned by the Saturn Clients. Ms. Tian is the Managing Member of SVCM GP LLC, the general partner of Saturn Capital. No Saturn Client holds or beneficially owns five percent or more of the outstanding shares of the Company. Each of Saturn Capital and Ms. Tian disclaims beneficial ownership of any of the shares held by the Saturn Clients. The address of each entity and person listed above is 919 Congress Avenue, Suite 830, Austin, TX 78701.

(7) Based on a Schedule 13G filed by Perceptive Advisors LLC (“Perceptive Advisors”), Perceptive Life Sciences Master Fund, Ltd. (“Perceptive Fund”) and Joseph Edelman on November 3, 2025 reporting ownership as of October 27, 2025. Perceptive Advisors, Perceptive Fund and Mr. Edelman had shared voting power and shared dispositive power with respect to (i) 5,913,165 shares of common stock and (ii) 151,515 shares of common stock issuable upon the exercise of warrants. The terms of the warrants provide that the warrants may not be exercised if, after such exercise, the Reporting Persons would beneficially own, as determined in accordance with Section 13(d) if the Securities Exchange Act of 1934, as amended, more than 9.99% of the shares of common stock then issued and outstanding. Perceptive Advisors serves as the investment manager to the Master Fund. Mr. Edelman is the managing member of Perceptive Advisors. The address of each entity and person listed above is 51 Astor Place, 10th Floor, New York, NY 10003.

(8) Based on the Company’s records and a Schedule 13D/A filed by Growth Equity Opportunities 18 VGE, LLC (“GEO”), NEA 18 Venture Growth Equity, L.P. (“NEA 18 VGE”), NEA Partners 18 VGE, L.P. (“NEA Partners 18 VGE”), NEA 18 VGE GP, LLC (“NEA 18 VGE LLC” and, together with NEA Partners 18 VGE, the “Control Entities”), Ali Behbahani (“Behbahani”), Carmen Chang (“Chang”), Anthony A. Florence, Jr. (“Florence”), Mohamad H. Makhzoumi (“Makhzoumi”), Edward T. Mathers (“Mathers”), Scott D. Sandell (“Sandell”), Paul Walker (“Walker”) and Rick Yang (“Yang” and collectively with GEO, NEA 18 VGE, the Control Entities, Behbahani, Chang, Florence, Makhzoumi, Mathers, Sandell and Walker, the “GEO Persons”) on October 29, 2025 reporting ownership as of October 27, 2025. The GEO Persons have shared voting power and shared dispositive power with respect to (i) 3,233,744 shares of common stock, (ii) 610,190 shares of common stock issuable upon the exercise of Pre-Funded Warrants, (iii) 760,735 shares of common stock issuable upon the exercise of certain other pre-funded warrants (“Non-PIPE Pre-Funded Warrants”), (iv) 456,839 shares of common stock issuable upon the exercise of Common Warrants and (v) 189,393 shares of common stock issuable upon the exercise of Class C Warrants, in each case held by GEO. The number of shares set forth under “Shares beneficially owned” above gives effect to beneficial ownership limitations in certain warrants as described below. Without giving effect to such beneficial ownership limitations, the GEO Persons would have shared voting power and shared dispositive power with respect to (i) 3,233,744 shares of common stock, (ii) 5,311,810 shares of common stock issuable upon the exercise of Pre-Funded Warrants, (iii) 610,190 shares of common stock issuable upon the exercise of the Non-PIPE Pre-Funded Warrants, (iv) 456,839 issuable upon the exercise of Common Warrants and (v) 189,393 shares of common stock issuable upon the exercise of Class C Warrants, in each case held by GEO. The Pre-Funded Warrants carry a limitation on exercise preventing GEO from exercise if such exercise results in GEO beneficially owning in excess of 4.99% of the number of shares of common stock, which percentage can be increased or decreased at the option of GEO upon 61 days prior notice however not to exceed 19.99%. The Non-PIPE Pre-Funded Warrants carry a limitation on exercise preventing GEO from exercise if such exercise results in GEO beneficially owning in excess of 9.99% of the number of shares of common stock, which percentage can be increased or decreased at the option of GEO upon 61 days prior notice however not to exceed 9.99%. The Common Warrants and the Class C Warrants carry a limitation on exercise preventing GEO from exercise if such exercise results in GEO beneficially owning in excess of 4.99% of the number of shares of common stock, which percentage can be increased or decreased at the option of GEO upon 61 days prior notice however not to exceed 9.99%. NEA 18 VGE is the sole member of GEO and NEA Partners 18 VGE is the sole general partner of NEA 18 VGE. NEA 18 VGE GP, LLC is the sole general partner of NEA Partners 18 VGE. Behbahani, Chang, Florence, Makhzoumi, Mathers, Sandell, Paul and Yang are the managers of NEA 18 VGE LLC. The address of the principal business office of GEO, NEA 18 VGE, each Control Entity and Sandell is New Enterprise Associates, 1954 Greenspring Drive, Suite 600, Timonium, MD 21093. The address of the principal business office of Behbahani, Chang, Makhzoumi, Walker and Yang is New Enterprise Associates, 2855 Sand Hill Road, Menlo Park, California 94025. The address of the principal business office of Florence and Mathers is New Enterprise Associates, 104 5th Avenue, 19th Floor, New York, NY 10001.

(9) Based on a Schedule 13G/A filed by Trails Edge Capital Partners, LP (“Trails Edge Capital”), Trails Edge Biotechnology Master Fund, LP (“Trails Edge Biotechnology”) and Ortav Yehudai on February 17, 2026 reporting ownership as of December 31, 2025.

Each of Trails Edge, Trails Edge Fund and Mr. Yehudai has sole voting power and sole dispositive power with respect to (i) 2,571,478 shares of common stock and (ii) 2,655,744 shares of common stock issuable upon the exercise of Pre-Funded Warrants, in each case held by Trails Edge Biotechnology. The Pre-Funded Warrants contain an issuance limitation that prohibits the holder from exercising the Pre-Funded Warrants to the extent that after giving effect to such issuance after the exercise, the holder (together with the holder's affiliates and any other persons acting as a group together with the holder or any of the holder's affiliates) would beneficially own in excess of 9.99% of common stock outstanding immediately after giving effect to the issuance of the shares of common stock issuable upon the exercise of the Pre-Funded Warrants. Trails Edge Capital, as the investment manager to Trails Edge Biotechnology, may be deemed to beneficially own these securities. Mr. Yehudai, as the Chief Investment Officer of Trails Edge Capital, exercises voting and investment discretion with respect to these securities and as such may be deemed to beneficially own such securities. The address of each entity and person listed above is 3455 Peachtree Road NE, 5th Floor, Atlanta, GA 30326.

(10) Based on a Schedule 13G filed by Deep Track Capital, LP (“Deep Track”), Deep Track Biotechnology Master Fund, Ltd. (“Deep Track Master Fund”) and David Kroin on August 19, 2025 reporting ownership as of August 12, 2025. Deep Track Capital, Deep Track Master Fund and Mr. Kroin have shared voting power and shared dispositive power with respect to (i) 1,122,484 shares of common stock and (ii) 4,162,137 shares of common stock issuable upon the exercise of Pre-Funded Warrants, in each case held by Deep Track Master Fund. The Pre-Funded Warrants carry a limitation on exercise preventing Deep Track Master Fund from exercise if such exercise results in Deep Track Master Fund beneficially owning in excess of 9.99% of the number of shares of common stock. David Kroin is the managing member of Deep Track Capital GP, LLC (“Deep Track GP”). Deep Track GP is the general partner of Deep Track Capital, LP (“Deep Track IM”). Deep Track IM is the investment manager of Deep Track Master Fund. The address of each of the foregoing entities and persons is 200 Greenwich Avenue, 3rd Floor, Greenwich, CT 06830.

(11) Consists of 86,206 shares of common stock.

(12) Consists of 831,862 shares of common stock underlying options that are currently exercisable or exercisable within 60 days of March 1, 2026.

(13) Consists of 91,221 shares of common stock.

(14) Consists of (i) 3,222 shares of common stock and (ii) 2,261 shares of common stock underlying options that are currently exercisable or exercisable within 60 days of March 1, 2026.

(15) Consists of (i) 3,222 shares of common stock and (ii) 408 shares of common stock underlying options that are currently exercisable or exercisable within 60 days of March 1, 2026.

(16) Consists of (i) 6,383 shares of common stock and (ii) 875 shares of common stock underlying options that are currently exercisable or exercisable within 60 days of March 1, 2026.

(17) Consists of (i) 4,055 shares of common stock and (ii) 2,886 shares of common stock underlying options that are currently exercisable or exercisable within 60 days of March 1, 2026.

(18) Consists of (i) 194,309 shares of common stock and (ii) 838,292 shares of common stock underlying options that are currently exercisable or exercisable within 60 days of March 1, 2026.

Delinquent Section 16(a) Reports

Section 16(a) of the Exchange Act requires our directors, officers and persons who beneficially own more than 10% of a registered class of our equity securities to file with the SEC initial reports of ownership and reports of changes in ownership of our common stock and other equity securities. To our knowledge, based solely on our review of Forms 3, 4 and 5 filed with the SEC, or written representations that no Form 5 was required, during the year ended December 31, 2025, we believe that our directors, officers and persons who beneficially own more than 10% of a registered class of our equity securities timely filed all reports required under Section 16(a) of the Exchange Act, except that, due to administrative error, one Form 3 was filed late with respect to Natasha Thoren, our former Chief Legal Officer.

EXECUTIVE COMPENSATION

Our Compensation Committee is primarily responsible for establishing and reviewing our general compensation strategy. See the section captioned “Compensation Committee Processes and Procedures.”

2025 SUMMARY COMPENSATION TABLE

The following table shows the total compensation awarded to, earned by or paid to, during the fiscal years ended December 31, 2025 and December 31, 2024, the following individuals, for all services rendered in all capacities: (1) each individual who served as our Principal Executive Officer during the fiscal year ended December 31, 2025, and (2) our two most highly compensated executive officers (other than our Principal Executive Officer) who earned more than $100,000 during the fiscal year ended December 31, 2025 and were serving as executive officers as of such date. We refer to these four individuals in this Proxy Statement as our named executive officers, or NEOs.

Our NEOs for 2025 who appear in the Summary Compensation Table are:

•Adam R. Craig, M.D., Ph.D., M.B.A., our Executive Chairman;

•Paula Ragan, Ph.D., our former President and Chief Executive Officer;

•John Volpone, M.B.A., our President and Chief Operating Officer; and

•David Kirske, our Chief Financial Officer, Treasurer and Corporate Secretary



Name and Principal Position	Year	Salary ($)	Bonus ($)(1)	Stock Awards ($)		Option Awards ($)		Non-Equity Incentive Plan Compensation ($)		All Other Compensation ($)		Total ($)
Adam R. Craig, M.D., Ph.D., M.B.A. Executive Chairman(6)	2025	179,629	—	—		6,410,958	(3)	114,479	(4)	139	(5)	6,705,205
Paula Ragan, Ph.D. Former President and Chief Executive Officer	2025	420,170	—	1,081,575	(2)	—		—		1,138,824	(5)	2,640,569
	2024	654,156	—	312,962		857,686		305,818		14,419		2,145,041
John Volpone, M.B.A., President and Chief Operating Officer (6)	2025	176,538	—	—		6,410,958	(3)	75,006	(4)	4,985	(5)	6,667,487
David Kirske, Chief Financial Officer, Treasurer and Corporate Secretary (6)	2025	194,192	120,000	—		4,181,040	(3)	103,133	(4)	901	(5)	4,599,266

(1) The amount reported in the “Bonus” column for 2025 includes a one-time bonus for Mr. Kirske, which was earned and paid in 2025.

(2) The amounts reported in the “Stock Awards” column reflect the aggregate grant date fair value of restricted stock units awarded during 2025, computed in accordance with the provisions of Financial Accounting Standards Board Accounting Standards Codification Topic 718 (“ASC 718”), but excluding any estimated forfeitures related to service-based vesting conditions. See Note 16 to the X4 Pharmaceuticals Inc. Annual Report on Form 10-K for the year ended December 31, 2025 filed with the SEC on March 17, 2026, regarding assumptions underlying the valuation of equity awards. The amounts reported in this column reflect the total accounting expense for these restricted stock units and do not correspond to the actual economic value that may be received by our NEOs upon the vesting and settlement of the restricted stock units or any sale of the underlying shares of common stock.

(3) The amounts reported in the “Options Awards” column reflect the aggregate grant date fair value of stock options awarded during 2025, computed in accordance with the provisions of ASC 718 but disregarding any estimate of forfeitures related to service-based vesting conditions for this purpose. See Note 16 to the X4 Pharmaceuticals Inc. Annual Report on Form 10-K for the year ended December 31, 2025 filed with the SEC on March 17, 2026, regarding assumptions underlying the valuation of equity awards. The amounts reported in this column reflect the accounting expense for these options and do not correspond to the actual economic value that may be received by our NEOs upon the exercise of the options, as applicable, or any sale of the underlying shares of common stock. The amounts shown for 2025 include performance-based stock options and the aggregate grant date fair value is reported based on probable achievement of performance outcomes.

(4) The amounts reported in the “Non-Equity Incentive Plan Compensation” column for 2025 include amounts earned and paid for prorated annual, discretionary bonuses equal to 60%, 40% and 50% of base salary for Dr. Craig, Mr. Volpone, and Mr. Kirske, respectively. See “Narrative to Summary Compensation Table—Non-Equity Incentive Plan Compensation” below for more information.

(5) The amounts reported in the “All Other Compensation” column for fiscal year 2025 reflects severance payments, prorated annual bonus payments and 401(k) matching contributions for Dr. Ragan; 401(k) matching contributions for Mr. Volpone and the value of group term life insurance provided to each NEO.

(6) Dr. Craig and Messrs. Volpone and Kirske were not NEOs for 2024. Dr. Craig was appointed Executive Chairman on August 11, 2025. Mr. Volpone was appointed President on August 11, 2025 and Chief Operating Officer on September 16, 2025. Mr. Kirske was appointed the Chief Financial Officer, Treasurer and Corporate Secretary on August 11, 2025.

NARRATIVE TO SUMMARY COMPENSATION TABLE

The material terms of the elements of our executive compensation program are described below.

Base Salary

Each NEO’s base salary is a fixed component of annual compensation for performing specific duties and functions, and has been established by our Board taking into account each individual’s role, responsibilities, skills, and experience. Effective January 1, 2025, our Board, upon the recommendation of the Compensation Committee, set Dr. Ragan’s base salary at $654,156, consistent with the prior year. Dr. Ragan resigned from the Company effective August 11, 2025, and, in accordance with her employment agreement, was paid a prorated salary of $420,170, reflecting the time she served as our Chief Executive Officer during 2025. The annual base salaries for Dr. Craig, Mr. Volpone, and David Kirske were established consistent with their employment agreements in connection with their appointments as our named executive officers and are £340,000, or approximately $457,878, $450,000, and $495,000, respectively, for the fiscal year ended December 31, 2025. As of the date hereof, these base salary amounts remain unchanged for 2026.

Bonus Compensation

Our annual bonus program is intended to reward our NEOs for individual and Company-wide performance over the calendar year and to receive competitive compensation commensurate with their responsibilities, experience, and tenure. For a further description of the terms of the annual bonus program, see the summaries set forth in the Employment and Change in Control Arrangements section below.

Long-Term Equity Incentives

Our equity grant program is intended to align the interests of our NEOs with those of our stockholders and to motivate them to make important contributions to our performance. In February 2025, we granted restricted stock units as annual refresh grants to Dr. Ragan. Upon commencement of their employment in August 2025, we granted performance-based and time-based stock options to Dr. Craig, Mr. Volpone and Mr. Kirske. In addition, the Company conditionally approved awards to Dr. Craig, Mr. Volpone, and Mr. Kirske of the Contingent RSU Awards (described in more detail on page 19), which are designed to compensate these officers for the lost value attributable to the higher exercise price applicable to the stock options granted on August 14, 2025. The Contingent RSU Awards will only be granted if stockholders approve Proposal 3.

Timing of Grants of Equity Awards

We do not have a formal policy regarding the granting practices of our equity awards. We generally make grants to our employees upon commencement of employment and annually in connection with our annual review of corporate and individual performance. It is the Compensation Committee’s long-standing practice to review the Company’s and individual employee’s performance at the end of each fiscal year and, based on those reviews, approve the granting of annual equity awards for our employees in the following January or February. However, our Board and Compensation Committee, as applicable, carefully review any potential material nonpublic information before granting equity awards. We do not time our equity award grants either to take advantage of a depressed stock price, or an anticipated increase in stock price, and we have limited the amount of discretion that can be exercised in connection with the timing of equity award grants. We also do not time the release of material nonpublic information based on equity award grant dates and do not time the disclosure of material nonpublic information for the purpose of affecting the value of executive compensation.

During 2025, we did not grant any stock options, stock appreciation rights or similar option-like instruments to any of our NEOs during any period beginning four business days before and ending one business day after the filing or furnishing of a Form 10-Q, Form 10-K or Form 8-K that discloses material nonpublic information.

401(k) Plan

We maintain a defined contribution retirement plan that provides eligible U.S. employees with an opportunity to save for retirement on a tax-advantaged basis. Eligible employees may defer eligible compensation on a pre-tax basis, up to the statutorily prescribed annual limits on contributions under the Code. Contributions are allocated to each participant’s individual account and are then invested in selected investment alternatives according to the participants’ directions. Employees are immediately and fully vested in their contributions. We provide a discretionary matching contribution equal to 100% of employee contributions up to a maximum of 4% of eligible compensation, as defined under the 401(k) plan. The 401(k) plan is intended to be qualified under Section 401(a) of the Code with the 401(k) plan’s related trust intended to be tax

exempt under Section 501(a) of the Code. As a tax-qualified retirement plan, contributions to the 401(k) plan and earnings on those contributions are not taxable to the employees until distributed from the 401(k) plan. All of our employees are eligible to participate in the 401(k) Plan on the same terms as our NEOs.

Health and Welfare Benefits

All of our full-time employees, including our NEOs, and certain of our part-time employees are eligible to participate in our health and welfare benefit plans, including our medical, dental, life and long-term disability insurance plans. Our health and welfare benefit plans do not discriminate in scope, terms or operation in favor of our executive officers.

Perquisites and Personal Benefits

We do not provide any perquisites or personal benefits to our NEOs not otherwise made available to our other employees.

Employment and Change in Control Arrangements

Adam R. Craig, M.D., Ph.D., M.B.A.

On August 11, 2025, we entered into an executive employment agreement with Dr. Craig. Pursuant to the employment agreement, Dr. Craig’s compensation consists of base salary at an annual rate approved by our Board or an appropriate committee thereof, employee benefits, vacation, reimbursement of ordinary and reasonable out-of-pocket expenses and coverage under our Director and Officer (“D&O”) insurance policies, subject to the terms and conditions of such policies. Dr. Craig’s 2025 base salary was £340,000, or approximately $457,878, for 2025. As of the date hereof, Dr. Craig’s base salary amount remains unchanged for 2026.

Dr. Craig is also eligible to earn an annual discretionary bonus in an amount equal to 60% of his base salary. The amount of the bonus, if any, will be determined in the sole discretion of the Company and based, in part, on Dr. Craig’s performance and the performance of the Company during the calendar year, subject to Dr. Craig’s continued employment through the date of payment. The bonus paid for the calendar year 2025 was prorated by the percentage of the year that Dr. Craig was employed by the Company, and was paid on December 16, 2025.

Pursuant to his employment agreement, if Dr. Craig’s employment is terminated for any reason, Dr. Craig is entitled to receive his accrued but unpaid salary, accrued but unused vacation days, the amount of any properly incurred expenses prior to termination not yet reimbursed and other benefits. In addition to the foregoing, if Dr. Craig’s employment is terminated by us without cause or if Dr. Craig resigns for good reason, each term as defined in the agreement, Dr. Craig will be entitled to the following: (a) his base salary for a period of 12 months following such termination, (b) a pro-rated portion of his target annual bonus for the calendar year in which the termination occurs based on the period worked by him during such calendar year prior to termination, (c) so long as Dr. Craig is eligible for coverage under our health insurance plan, elects coverage, was covered prior to termination, and elects to exercise his rights under COBRA to continue participation in such plan, we will pay an amount equal to the monthly employer contribution we pay for current employees under such plan until the earlier of six months from the date of his termination or the date he is eligible to receive health benefits through another employer, and (d) Dr. Craig will become vested in all unvested outstanding equity awards granted to Dr. Craig. In lieu of the foregoing, if Dr. Craig’s employment is terminated without cause or if he resigns for good reason, in either case within the one-year period following a change of control, as that term is defined in the agreement, Dr. Craig will be entitled to the following, in addition to his accrued but unpaid benefits: (a) his base salary for a period of 12 months following such termination, (b) 100% of his target annual bonus for the calendar year in which the termination occurs, (c) so long as Dr. Craig is eligible for coverage under our health insurance plan, elects coverage, was covered prior to termination, and elects to exercise his rights under COBRA to continue participation in such plan, we will pay an amount equal to the monthly employer contribution we pay for current employees under such plan until the earlier of six months from the date of Dr. Craig’s termination or the date he is eligible to receive health benefits through another employer, and (d) automatic vesting in all outstanding equity awards granted to Dr. Craig. As a condition to receiving the foregoing severance benefits, Dr. Craig must execute and not revoke a separation agreement in a form acceptable to us and which will include a complete release of claims and terms related to non-disparagement, non-competition, confidentiality and cooperation.

Dr. Craig’s employment agreement also contains his agreement to continue to abide by the terms of his non-competition, non-solicitation, non-disclosure and intellectual property agreement.

John Volpone, M.B.A.

On August 11, 2025, we entered into an executive employment agreement with Mr. Volpone. Pursuant to the employment agreement, Mr. Volpone’s compensation consists of base salary at an annual rate approved by our Board or an appropriate

committee thereof, employee benefits, vacation, reimbursement of ordinary and reasonable out-of-pocket expenses and coverage under our D&O insurance policies, subject to the terms and conditions of such policies. Mr. Volpone’s 2025 base salary was $450,000 for 2025. As of the date hereof, Mr. Volpone’s base salary amount remains unchanged for 2026.

Mr. Volpone is also eligible to earn an annual discretionary bonus in an amount equal to 40% of his base salary. The amount of the bonus , if any, will be determined in the sole discretion of the Company and based, in part on Mr. Volpone’s performance and the performance of the Company during the calendar year, subject to Mr. Volpone’s continued employment through the date of payment. The bonus paid for the calendar year 2025 was prorated by the percentage of the year that Mr. Volpone was employed by the Company, and was paid on December 16, 2025.

Pursuant to his employment agreement, if Mr. Volpone’s employment is terminated for any reason, Mr. Volpone is entitled to receive his accrued but unpaid salary, accrued but unused vacation days, the amount of any properly incurred expenses prior to termination not yet reimbursed and other benefits. In addition to the foregoing, if Mr. Volpone’s employment is terminated by us without cause or if Mr. Volpone resigns for good reason, each term as defined in the agreement, Mr. Volpone will be entitled to the following: (a) his base salary for a period of 12 months following such termination, (b) a pro-rated portion of his target annual bonus for the calendar year in which the termination occurs based on the period worked by him during such calendar year prior to termination, (c) so long as Mr. Volpone is eligible for coverage under our health insurance plan, elects coverage, was covered prior to termination, and elects to exercise his rights under COBRA to continue participation in such plan, we will pay an amount equal to the monthly employer contribution we pay for current employees under such plan until the earlier of six months from the date of his termination or the date he is eligible to receive health benefits through another employer, and (d) Mr. Volpone will become vested in all outstanding unvested equity awards granted to Mr. Volpone. In lieu of the foregoing, if Mr. Volpone’s employment is terminated without cause or if he resigns for good reason, in either case within the one-year period following a change of control, as that term is defined in the agreement, Mr. Volpone will be entitled to the following, in addition to his accrued but unpaid benefits: (a) his base salary for a period of 12 months following such termination, (b) 100% of his target annual bonus for the calendar year in which the termination occurs, (c) so long as Mr. Volpone is eligible for coverage under our health insurance plan, elects coverage, was covered prior to termination, and elects to exercise his rights under COBRA to continue participation in such plan, we will pay an amount equal to the monthly employer contribution we pay for current employees under such plan until the earlier of six months from the date of Mr. Volpone’s termination or the date he is eligible to receive health benefits through another employer, and (d) automatic vesting in all outstanding equity awards granted to Mr. Volpone. As a condition to receiving the foregoing severance benefits, Mr. Volpone must execute and not revoke a separation agreement in a form acceptable to us and which will include a complete release of claims and terms related to non-disparagement, non-competition, confidentiality and cooperation.

Mr. Volpone’s employment agreement also contains his agreement to continue to abide by the terms of his non-competition, non-solicitation, non-disclosure and intellectual property agreement.

David Kirske

On August 11, 2025, we entered into an executive employment agreement with Mr. Kirske. Pursuant to the employment agreement, Mr. Kirske’s compensation consists of base salary at an annual rate approved by our Board or an appropriate committee thereof, employee benefits, vacation, reimbursement of ordinary and reasonable out-of-pocket expenses and coverage under our D&O insurance policies, subject to the terms and conditions of such policies. Mr. Kirske’s 2025 base salary was $495,000 for 2025. As of the date hereof, Mr. Kirske’s base salary amount remains unchanged for 2026.

Mr. Kirske is also eligible to earn an annual discretionary bonus in an amount equal to 50% of his base salary. The amount of the bonus, if any, will be determined in the sole discretion of the Company and based, in part, on Mr. Kirske’s performance and the performance of the Company during the calendar year, subject to Mr. Kirske’s continued employment through the date of payment. The bonus paid for the calendar year 2025 was prorated by the percentage of the year that Mr. Kirske was employed by the Company and was paid on December 16, 2025. In addition, in accordance with his employment agreement, Mr. Kirske was eligible to a one-time bonus of $120,000 that would be paid six months following the commencement of his employment subject to Mr. Kirske’s continued employment with the Company. In recognition for his performance during 2025, the Board approved the accelerated payment of Mr. Kirske’s bonus in December 2025.

Pursuant to his employment agreement, if Mr. Kirske’s employment is terminated for any reason, Mr. Kirske is entitled to receive his accrued but unpaid salary, accrued but unused vacation days, the amount of any properly incurred expenses prior to termination not yet reimbursed and other benefits. In addition to the foregoing, if Mr. Kirske’s employment is terminated by us without cause or if Mr. Kirske resigns for good reason, each term as defined in the agreement, Mr. Kirske will be entitled to the following: (a) his base salary for a period of 12 months following such termination, (b) a pro-rated portion of his target annual bonus for the calendar year in which the termination occurs based on the period worked by him during such

calendar year prior to termination, (c) so long as Mr. Kirske is eligible for coverage under our health insurance plan, elects coverage, was covered prior to termination, and elects to exercise his rights under COBRA to continue participation in such plan, we will pay an amount equal to the monthly employer contribution we pay for current employees under such plan until the earlier of six months from the date of his termination or the date he is eligible to receive health benefits through another employer, and (d) Mr. Kirske will become vested in all outstanding unvested equity awards granted to Mr. Kirske. In lieu of the foregoing, if Mr. Kirske’s employment is terminated without cause or if he resigns for good reason, in either case within the one-year period following a change of control, as that term is defined in the agreement, Mr. Kirske will be entitled to the following, in addition to his accrued but unpaid benefits: (a) his base salary for a period of 12 months following such termination, (b) 100% of his target annual bonus for the calendar year in which the termination occurs, (c) so long as Mr. Kirske is eligible for coverage under our health insurance plan, elects coverage, was covered prior to termination, and elects to exercise his rights under COBRA to continue participation in such plan, we will pay an amount equal to the monthly employer contribution we pay for current employees under such plan until the earlier of six months from the date of Mr. Kirske’s termination or the date he is eligible to receive health benefits through another employer, and (d) automatic vesting in all outstanding equity awards granted to Mr. Kirske. As a condition to receiving the foregoing severance benefits, Mr. Kirske must execute and not revoke a separation agreement in a form acceptable to us and which will include a complete release of claims and terms related to non-disparagement, non-competition, confidentiality and cooperation.

Mr. Kirske’s employment agreement also contains his agreement to continue to abide by the terms of his non-competition, non-solicitation, non-disclosure and intellectual property agreement.

Paula Ragan, Ph.D.

On March 13, 2019, we entered into an amended and restated executive employment agreement with Dr. Ragan, which was subsequently amended on February 10, 2020 and April 15, 2020. Pursuant to the employment agreement, Dr. Ragan’s compensation consists of base salary at an annual rate approved by our Board or an appropriate committee thereof, an annual performance bonus as determined by our Board (provided that the target for such bonus shall be no less than 25% of Dr. Ragan’s annual base salary), employee benefits, vacation, reimbursement of ordinary and reasonable out-of-pocket expenses and coverage under our D&O insurance policies, subject to the terms and conditions of such policies. Dr. Ragan’s 2024 and 2025 base salary was $654,156.

On August 11, 2025, Dr. Ragan resigned as our Chief Executive Officer and her employment was terminated. Pursuant to her employment agreement, Dr. Ragan received her accrued but unpaid salary, accrued but unused vacation days, and the amount of any properly incurred expenses prior to termination not yet reimbursed and other benefits. In addition to the foregoing, as Dr. Ragan’s employment was terminated by us without cause, Dr. Ragan was entitled to the following: (a) her base salary for a period of 12 months following such termination, (b) a pro-rated portion of her target annual bonus for the calendar year in which the termination occurs, payable in a lump sum, (c) so long as Dr. Ragan is eligible for coverage under our health insurance plan, elects coverage, was covered prior to termination, and elects to exercise her rights under COBRA to continue participation in such plan, we will pay an amount equal to the monthly employer contribution we pay for current employees under such plan until the earlier of 12 months from the date of Dr. Ragan’s termination, or the date Dr. Ragan is eligible to receive health benefits through another employer, and (d) Dr. Ragan became vested in the additional number of outstanding time-based equity awards granted to Dr. Ragan that would have otherwise vested had Dr. Ragan remained employed for an additional 12 months after her termination date. In addition, our Board of Directors approved the vesting of all additional unvested awards that would not have vested pursuant to her employment agreement.

As a condition to receiving the foregoing severance benefits, Dr. Ragan executed and did not revoke a separation agreement in a form acceptable to us and which included a complete release of claims and terms related to non-disparagement, non-competition, confidentiality and cooperation. Dr. Ragan’s separation agreement also contains her agreement to continue to abide by the terms of her non-competition, non-solicitation, non-disclosure and intellectual property agreement.

In addition, Dr. Ragan’s employment agreement provides that in the event the severance and other benefits provided for or otherwise payable to Dr. Ragan constitute “parachute payments” within the meaning of Section 280G of the Internal Revenue Code of 1986, as amended (the “Code”) and are subject to the excise tax imposed by Section 4999 of the Code, we will pay either (i) Dr. Ragan’s severance benefits under the employment agreement in full or (ii) only a part of Dr. Ragan’s severance benefits under the employment agreement such that Dr. Ragan receives the largest payment possible without the imposition of the excise tax, in each case, depending upon which alternative would result in Dr. Ragan receiving the greater net after-tax payment.

OUTSTANDING EQUITY AWARDS AT FISCAL 2025 YEAR END

The following table shows for the fiscal year ended December 31, 2025, certain information regarding outstanding equity awards for the NEOs. The equity awards described below are subject to certain acceleration of vesting benefits pursuant to the NEOs’ employment agreements.


			Option Awards
Name	(1) Grant Date		Number of Securities Underlying Unexercised Options (#) Exercisable	Number of Securities Underlying Unexercised Options (#) Unexercisable	Option Exercise Price ($)	Option Expiration Date
Adam R. Craig, M.D., Ph.D., M.B.A.	8/12/2025	(3)	—	2,329,154	1.42	8/11/2035
	8/12/2025	(2)	—	1,609,873	1.42	8/11/2035
	8/14/2025	(2)	—	529,201	3.14	8/13/2035

John Volpone, M.B.A.	8/12/2025	(3)	—	2,329,154	1.42	8/11/2035
	8/12/2025	(2)	—	1,609,873	1.42	8/11/2035
	8/14/2025	(2)	—	529,201	3.14	8/13/2035

David Kirske	8/12/2025	(3)	—	1,552,769	1.42	8/11/2035
	8/12/2025	(4)	—	1,073,249	1.42	8/11/2035
	8/14/2025	(4)	—	352,800	3.14	8/13/2035

Paula Ragan, Ph.D.			—	—

(1) These stock option awards were granted pursuant to the Company’s 2019 Inducement Equity Incentive Plan, as amended from time to time (the “Inducement Plan”).

(2) One third of the shares subject to these time-based option awards shall vest on August 12, 2026, with the remainder vesting in equal installments each successive month thereafter for a period of 24 months, subject to the NEO continuing to provide services through each such date.

(3) The performance condition of these performance-based stock options was satisfied October 27, 2025. One third of the shares subject to these option awards, as adjusted based on the performance condition, shall vest on August 12, 2026, with the remainder vesting in equal installments each successive month thereafter for a period of 24 months, subject to the NEO continuing to provide services through each such date.

(4) One half of the shares subject to these options vested on February 12, 2026, with the remainder vesting in equal installments in each successive month thereafter for a period of 12 months, subject to Mr. Kirske continuing to provide services through each such date.

PAY VS. PERFORMANCE

SEC Form DEF 14A filed by X4 Pharmaceuticals Inc.