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
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 Definitive Proxy Statement
 Definitive Additional Materials
 Soliciting Material Under Rule 14a-12Pursuant to § 240.14a-12

X4 Pharmaceuticals, Inc.

(Name of Registrant as Specified In Its Charter)

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

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Table of Contents
X4 PHARMACEUTICALS, INC.
61 North Beacon Street, 4th Floor
Boston, Massachusetts 02134
NOTICE OF ANNUAL MEETING OF STOCKHOLDERS
To Be Held On June 2, 2021
Dear Stockholder of X4 Pharmaceuticals, Inc.

955 Massachusetts Avenue, 4th Floor

Cambridge, MA 02139

May 22, 2019

To Our Stockholders:

:

You are cordially invited to attend the 2019 annual meeting2021 Annual Meeting of stockholdersStockholders of X4 Pharmaceuticals, Inc., a Delaware corporation (the “Company”). Due to the public health concerns regarding the ongoing COVID-19 pandemic, the Annual Meeting will be held virtually and exclusively online via live audio-only webcast, on Wednesday, June 2, 2021 at 10:11:00 a.m. EDT on Monday, June 17, 2019 atEastern Time. The Annual Meeting will be held for the offices of Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C., One Financial Center, Boston, Massachusetts 02111.

Details regardingfollowing purposes:

1.     To elect the meeting, the business to be conducted at the meeting, and information about X4 Pharmaceuticals, Inc. that you should consider when you vote your shares are describedthree (3) nominees named in the accompanying proxy statement.

Atstatement (the “Proxy Statement”), David McGirr, M.B.A., Paula Ragan, Ph.D. and Michael S. Wyzga, to the Board of Directors to hold office until the 2024 Annual Meeting of Stockholders and until their successors are duly elected and qualified.

2.     To ratify the selection by the Audit Committee of the Board of Directors of PricewaterhouseCoopers LLP as the independent registered public accounting firm of the Company for its fiscal year ending December 31, 2021.
3.     To conduct any other business properly brought before the Annual Meeting.
These items of business are more fully described in the Proxy Statement accompanying this Notice.

You will be able to attend the Annual Meeting online, submit your questions during the Annual Meeting and vote your shares electronically during the meeting by visiting www.proxyvote.com. Because the Annual Meeting is being held electronically, you will not be able to attend the Annual Meeting in person.
The record date for the Annual Meeting is April 5, 2021. Only stockholders of record at the close of business on that date may vote at the Annual Meeting or any adjournment or postponement thereof.
Important Notice Regarding the Availability of Proxy Materials for the Annual Meeting to Be Held on June 2, 2021
The Notice & Proxy Statement and Annual Report on Form 10-K
are available at https://www.proxyvote.com.

By Order of the Board of Directors,
image_611.jpg
Paula Ragan, Ph.D.
President, Chief Executive Officer, Corporate Secretary and Director
Boston, Massachusetts
April 20, 2021









You are cordially invited to attend the Annual Meeting. Whether or not you expect to attend the Annual Meeting, please vote by telephone or through the Internet, or, if you receive a paper proxy card by mail, by completing and returning the proxy card mailed to you, as promptly as possible in order to ensure your representation at the Annual Meeting. Voting instructions are provided in the Notice of Internet Availability of Proxy Materials, or, if you receive a paper proxy card by mail, the instructions are printed on your proxy card and included in the accompanying proxy statement. 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 brokerage firm, bank or other agent and you wish to vote at the Annual Meeting, you must obtain a proxy issued in your name from that agent in order to vote your shares that are held in such agent’s name and account.













image_31.jpg
Table of Contents
TABLE OF CONTENTS
QUESTIONS AND ANSWERS ABOUT THESE PROXY MATERIALS AND VOTING
PROPOSAL 1 ELECTION OF DIRECTORS
INFORMATION REGARDING THE BOARD OF DIRECTORS AND CORPORATE GOVERNANCE
Independence of the Board of Directors
Board Leadership Structure
Role of the Board in Risk Oversight
Meetings of the Board of Directors
Information Regarding Committees of the Board of Directors
Audit Committee
Compensation Committee
Nominating and Corporate Governance Committee
Stockholder Communications with the Board of Directors
Code of Ethics
PROPOSAL 2 RATIFICATION OF SELECTION OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM
EXECUTIVE OFFICERS
SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT
EXECUTIVE COMPENSATION
Summary Compensation Table
Outstanding Equity Awards at Fiscal Year-End
Narrative to Summary Compensation Table
Director Compensation Table
Narrative to Director Compensation Table
TRANSACTIONS WITH RELATED PERSONS AND INDEMNIFICATION
Related-Person Transactions Policy and Procedures
Certain Related-Person Transactions
Indemnification
HOUSEHOLDING OF PROXY MATERIALS
OTHER MATTERS













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X4 PHARMACEUTICALS, INC.
61 North Beacon Street, 4th Floor
Boston, Massachusetts 02134
PROXY STATEMENT
FOR THE 2021 ANNUAL MEETING OF STOCKHOLDERS
June 2, 2021
QUESTIONS AND ANSWERS ABOUT THESE PROXY MATERIALS AND VOTING

Why did I receivea 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. Accordingly, we have sent you a Notice of Internet Availability of Proxy Materials (the “Notice”) because the Board of Directors (the “Board”) of X4 Pharmaceuticals, Inc. (sometimes referred to a the “Company” or “X4”) is soliciting your proxy to vote at the 2021 Annual Meeting of Stockholders (the “Annual Meeting”), including at any adjournments or postponements of the Annual Meeting. All stockholders will have the ability to access the proxy materials on the website referred to in the Notice or request to receive a printed set of the proxy materials. Instructions on how to access the proxy materials over the internet or to request a printed copy may be found in the Notice.
We intend to mail the Notice on or about April 23, 2021 to all stockholders of record entitled to vote at the Annual Meeting.
Why are you holding a virtual Annual Meeting?

As part of our effort to maintain a safe and healthy environment for our directors, members of management and stockholders who wish to attend the Annual Meeting, in light of the ongoing COVID-19 pandemic we believe that hosting a virtual meeting is in the best interest of the Company and its stockholders and enables increased stockholder attendance and participation because stockholders can participate from any location around the world. Stockholders will have the same rights and opportunities to participate as they would have at an in-person meeting.

Will I receive any other proxy materials by mail?
We may send you a proxy card, along with a second Notice, on or after May 3, 2021.
How do I attend the Annual Meeting?

You cannot attend the Annual Meeting physically. You can attend the annual meeting one personby visiting www.virtualshareholdermeeting.com/XFOR2021, where you will be electedable to listen to the Annual Meeting live, submit questions and vote online.

The meeting will be held on Wednesday, June 2, 2021 at 11:00 a.m. Eastern Time. We encourage you to access the Annual Meeting 15 minutes prior to the start time to allow time for online check-in. We have worked to offer the same participation opportunities as would be provided at an in-person meeting while further enhancing the online experience available to all stockholders regardless of their location. However, please be aware that you must bear any costs associated with your internet access, such as usage charges from internet access providers and telephone companies. 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.

In order to enter the Annual Meeting virtually, you will need the unique 16-digit control number, which is included in the Notice or on your proxy card if you are a stockholder of record of the shares, or included with your voting instruction card and voting instructions received from your broker, bank, trustee, or nominee if you are the beneficial owner of the shares held in “street name.”


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What if I cannot virtually attend the Annual Meeting?

You may vote your shares electronically before the meeting by internet, by proxy or by telephone as described below. You do not need to access the Annual Meeting audio-only webcast to vote if you submitted your vote via proxy, by internet or by telephone in advance of the Annual Meeting.

Who can vote at the Annual Meeting?
Only stockholders of record at the close of business on April 5, 2021 will be entitled to vote at the Annual Meeting. On this record date, there were 23,665,660 shares of common stock outstanding and entitled to vote. A list of stockholders entitled to vote at the Annual Meeting will be available at our boardprincipal executive offices for examination during normal business hours by any stockholder for any purpose germane to the Annual Meeting for a period of directors. In addition,ten days prior to the Annual Meeting through the close of the Annual Meeting.
Stockholder of Record: Shares Registered in Your Name
If on April 5, 2021, your shares were registered directly in your name with our transfer agent, Computershare Trust Company, N.A., then you are a stockholder of record. As a stockholder of record, you may vote at the Annual Meeting virtually or vote by proxy prior to the Annual Meeting. Whether or not you plan to attend the Annual Meeting, we will ask stockholdersurge you to ratifyvote by proxy electronically through the appointmentInternet, over the telephone or by completing and returning a printed proxy card that you may request or that we may elect to deliver at a later time to ensure your vote is counted.
Beneficial Owner: Shares Registered in the Name of a Broker or Bank
If on April 5, 2021,your shares were held not in your name but rather in an account at a brokerage firm, bank or other similar organization, then you are the beneficial owner of shares held in “street name” and the Notice isbeing forwarded to you by that organization. The organization holding your account is considered to be the stockholder of record for purposes of voting at the Annual Meeting. As a beneficial owner, you have the right to direct your broker, bank or other agent regarding how to vote the shares in your account. You are also invited to attend the Annual Meeting. However, since you are not the stockholder of record, you may not vote your shares at the Annual Meeting even if you participate virtually unless you request and obtain a valid proxy from your broker, bank or other agent.
What am I voting on?
There are two matters scheduled for a vote:
Election of three (3) directors to hold office until the 2024 Annual Meeting of Stockholders (Proposal 1); and
Ratification of selection by the Audit Committee of the Board of Directors of PricewaterhouseCoopers LLP as our independent registered public accounting firm for our fiscal year ending December 31, 2019. Our board2021 (Proposal 2).
What if another matter is properly brought before the Annual Meeting?
The Board knows of directors recommends the approval of each of these proposals. Suchno other businessmatters that will be transacted as maypresented for consideration at the Annual Meeting. If any other matters are properly comebrought before the annual meeting.

We hopemeeting, 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?
With respect to Proposal 1, you will be ablemay either vote “FOR” all the nominees to attend the annual meeting.Board or you may “WITHHOLD” your vote for any nominee you specify. With respect to Proposal 2, you may vote “FOR” or “AGAINST” or abstain from voting.
The procedures for voting are fairly simple:
Stockholder of Record: Shares Registered in Your Name
If you are a stockholder of record, you may vote electronically over the internet before or during the Annual Meeting, vote by proxy through the Internet, vote by proxy over the telephone, or vote by proxy using a proxy card that you may request or that we may elect to deliver at a later time. Whether or not you plan to attend the annual meeting or not, it is important that you cast your vote either in person or by proxy. You may vote over the Internet as well as by telephone or by mail. When you have finished reading the proxy statement, you are urged to vote in accordance with the instructions set forth in the proxy statement. We encouragevirtual Annual Meeting, we urge you to vote by proxy soto ensure your vote is counted. You may still attend the Annual Meeting virtually and vote electronically even if you have already voted by proxy.

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To vote through the Internet before the Annual Meeting, go to www.proxyvote.com to complete an electronic proxy card. You will be asked to provide the 16-digit control number from the Notice. Your Internet vote must be received by 11:59 p.m., Eastern Time, onJune 1, 2021 to be counted.
To vote your shares electronically at the Annual Meeting, you will need to visit www.virtualshareholdermeeting.com/XFOR2021 during the Annual Meeting while the polls are open and follow the instructions provided. You will be asked to provide the control number from the Notice and follow the instructions.
To vote over the telephone from a location in the United States, dial toll-free 1-800-690-6903 using a touch-tone phone and follow the recorded instructions. You will be asked to provide the control number from the Notice. Your telephone vote must be received by 11:59 p.m., Eastern Time, on June 1, 2021 to be counted.
To vote by using a printed proxy card that may be delivered to you, simply complete, sign and date the proxy card and return it promptly in the envelope provided. If you return your signed proxy card to us before the Annual Meeting, we will vote your shares as you direct.

Beneficial Owner: Shares Registered in the Name of Broker or Bank
If you are a beneficial owner of shares registered in the name of your broker, bank or other agent, you should have received a Notice containing voting instructions from that organization rather than from us. Simply follow the voting instructions in the Notice to ensure that your vote is counted. To vote electronically at the Annual Meeting, you must obtain a valid proxy from your broker, bank or other agent. Follow the instructions from your broker, bank or other agent included with these proxy materials, or contact that organization to request a proxy form.

We provide Internet proxy voting to allow you to vote your shares online, with procedures designed to ensure the authenticity and correctness of your proxy vote instructions. However, please be aware that you must bear any costs associated with your Internet access, such as usage charges from internet access providers and telephone companies.
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 April 5, 2021.
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 Internetor electronically at the Annual Meeting, your shares will not be voted.
If you return a signed and dated proxy card or otherwise vote without marking voting selections, your shares will be representedvoted, as applicable, “FOR” the election of all three nominees for director and voted“FOR” the ratification of the selection of our independent registered public accounting firm. If any other matter is properly presented at the meeting, whetherAnnual Meeting, your proxyholder (one of the individuals named on your 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 provide my broker or bank with voting instructions, what happens?
If you are a beneficial owner of shares held in street name and you do not instruct your broker, bank or other agent how to vote your shares, your broker, bank or other agent may still be able to vote your shares in its discretion. In this regard, under the rules of the New York Stock Exchange (“NYSE”), brokers, banks and other securities intermediaries that are subject to NYSE rules may use their discretion to vote your “uninstructed” shares with respect to matters considered to be “routine” under NYSE rules, but not with respect to “non-routine” matters. In this regard, Proposal 1 is considered to be “non-routine” under NYSE rules meaning that your broker may not vote your shares on this proposal in the absence of your voting instructions. However, Proposals 2 is considered to be a “routine” matter under NYSE rules, meaning that if you do not return voting instructions to your broker by its deadline, your shares may be voted by your broker in its discretion on Proposal 2. Accordingly, if you own shares through a nominee, such as a broker, bank or other agent, please be sure to instruct your nominee how to vote to ensure that your vote is counted on all of the proposals.
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If you are a beneficial owner of shares held in street name, in order to ensure your shares are voted in the way you would prefer, you must provide voting instructions to your broker, bank or other agent by the deadline provided in the materials you receive from your broker, bank or other agent.
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 proxiesWe 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. You can attend.

Thankrevoke your proxy at any time before the final vote at the Annual Meeting. If you are the record holder of your shares, you may revoke your proxy 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 electronically. Simply attending the Annual Meeting virtually will not, by itself, revoke your proxy. Even if you plan to attend the Annual Meeting virtually, we recommend that you also submit your proxy or voting instructions or vote by telephone or through the Internet so that your vote will be counted if you later decide not to attend the Annual Meeting.
Your most current proxy card or telephone or Internet proxy is the one that is counted.
Beneficial Owner: Shares Registered in the Name of Broker or Bank
If your shares are held by your broker, bank or other agent, you should follow the instructions provided by your broker, bank or other agent.
When are stockholder proposals and director nominations due for next year’s annual meeting?
To be considered for inclusion in next year’s proxy materials, your continued support ofproposal must be submitted in writing by December 24, 2021, to our Corporate Secretary, c/o X4 Pharmaceuticals, Inc. We look forward, 61 North Beacon Street, 4th Floor, Boston, Massachusetts 02134.
Our bylaws also establish an advance notice procedure if you wish to seeingpresent a proposal (including a director nomination) before an annual meeting of stockholders but you are not requesting that your proposal or nomination be included in next year’s proxy materials. To be timely for our 2022 Annual Meeting of Stockholders, our Corporate Secretary must receive the written notice at our principal executive offices not later than the annual meeting.

Sincerely,

LOGO

Paula Ragan, Ph.D.

President, Chief Executive Officerclose of business on March 4, 2022nor earlier than the close of business on February 2, 2022. However, if we hold our 2022 Annual Meeting of Stockholders more than 30 days before or after June 2, 2022 (the one-year anniversary date of the 2021 Annual Meeting of Stockholders), then timely notice of a stockholder proposal that is not intended to be included in our proxy statement must be received not earlier than the close of business on the 120th day prior to the 2022 Annual Meeting of Stockholders and Secretary

not later than the close of business on the later of (a) the 90th day prior to the 2022 Annual Meeting of Stockholders and (b) the 10th day following the day on which the one of the following first occurs: (i) mailing of notice of the date of the 2022 Annual Meeting of Stockholders and (ii) the

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X4 Pharmaceuticals, Inc.

955 Massachusetts Avenue, 4th Floor

Cambridge, MA 02139

May 22, 2019

NOTICE OF 2019 ANNUAL MEETING OF STOCKHOLDERS


first public announcement of the date of the 2022 Annual Meeting of Stockholders. You are also advised to review our bylaws, which contain additional requirements about advance notice of stockholder proposals and director nominations.

How are votes counted?
Votes will be counted by the inspector of election appointed for the Annual Meeting, who will separately count, for the proposal to elect directors (Proposal 1), votes “For,” “Withhold” and broker non-vote, and, with respect to Proposal 2, votes “For” and “Against,” abstentions and, if applicable, broker non-votes. Abstentions will be counted towards the vote total for Proposal 2 and will have the same effect as “Against” votes. Broker non-votes on Proposal 1 will have no effect and will not be counted towards the vote total for any of those proposals.
What are “broker non-votes”?
As discussed above, when a beneficial owner of shares held in street name does not give voting instructions to his or her broker, bank or other securities intermediary holding his or her shares as to how to vote on matters deemed to be “non-routine” under NYSE rules, the broker, bank or other such agent cannot vote the shares. These un-voted shares are counted as “broker non-votes.” The NYSE has advised us that Proposal 1 is considered to be “non-routine” under NYSE rules and we therefore expect broker non-votes to exist in connection with that proposal.
As a reminder, if you are a beneficial owner of shares held in street name, in order to ensure your shares are voted in the way you would prefer, you must provide voting instructions to your broker, bank or other agent by the deadline provided in the materials you receive from your broker, bank or other agent.

How many votes are needed to approve each proposal?
The following table summarizes the minimum vote needed to approve each proposal and the effect of abstentions and broker non-votes.
TIME:

10:00 a.m. EDT

DATE:Proposal
Number

June 17, 2019

PLACE:

Offices of Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C., One Financial Center, Boston, MA 02111

PURPOSES:

  1.Proposal Description

To elect one director to serve a three-year term expiring in 2022;

  2.Vote Required for Approval

To ratify

Effect of
Abstentions
Effect of Broker
Non-Votes
1Election of directorsThe three nominees receiving the appointmentmost “For” votes; withheld votes will have no effect.No effectNo effect
2Ratification of the selection of PricewaterhouseCoopers LLP as our independent registered public accounting firm for the fiscal year ending December 31, 2019; and

3.

To transact such other business that is properly presented at the annual meeting and any adjournments or postponements thereof.

WHO MAY VOTE:

You may vote if you were the record owner of X4 Pharmaceuticals, Inc. common stock at the close of business on April 29, 2019. A list of stockholders of record will be available at the annual meeting and, during the 10 days prior to the annual meeting, at our principal executive offices located at 955 Massachusetts Avenue, 4th Floor, Cambridge, Massachusetts 02139.

All stockholders are cordially invited to attend the annual meeting.Whether or not you plan to attend the annual meeting, we urge you to vote and submit your proxy over the Internet or by telephone or mail in order to ensure the presence of a quorum.You may change or revoke your proxy at any time before it is voted at the meeting.

BY ORDER OF OUR BOARD OF DIRECTORS

LOGO

Paula Ragan, Ph.D.

President, Chief Executive Officer and Secretary


TABLE OF CONTENTS

PAGE

IMPORTANT INFORMATION ABOUT THE ANNUAL MEETING AND VOTING

2  

SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT

7  

MANAGEMENT AND CORPORATE GOVERNANCE

10  

EXECUTIVE OFFICER AND DIRECTOR COMPENSATION

18  

EQUITY COMPENSATION PLAN INFORMATION

34  

REPORT OF AUDIT COMMITTEE

35  

SECTION 16(a) BENEFICIAL OWNERSHIP REPORTING COMPLIANCE

36  

CERTAIN RELATIONSHIPS AND RELATED PERSON TRANSACTIONS

37  

PROPOSAL NO. 1: ELECTION OF DIRECTORS

49  

PROPOSAL NO. 2: RATIFICATION OF APPOINTMENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

50  

CODE OF BUSINESS CONDUCT AND ETHICS

53  

OTHER MATTERS

53  

STOCKHOLDER PROPOSALS AND NOMINATIONS FOR DIRECTOR

53  


X4 PHARMACEUTICALS, INC.

955 Massachusetts Avenue, 4th Floor

Cambridge, MA 02139

PROXY STATEMENT FOR THE X4 PHARMACEUTICALS, INC.

2019 ANNUAL MEETING OF STOCKHOLDERS TO BE HELD ON MONDAY, JUNE 17, 2019

This proxy statement, along with the accompanying notice of 2019 annual meeting of stockholders, contains information about the 2019 annual meeting of stockholders of X4 Pharmaceuticals, Inc., including any adjournments or postponements of the annual meeting. We are holding the annual meeting at 10:00 a.m., local time, on Monday, June 17, 2019 at the offices of Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C. located at One Financial Center, Boston, Massachusetts 02111.

In this proxy statement, we refer to X4 Pharmaceuticals, Inc. (formerly Arsanis, Inc.) and its direct and indirect subsidiaries as “the Company,” “we” and “us” and, for periods prior to March 13, 2019, we refer to X4 Therapeutics, Inc. (formerly X4 Pharmaceuticals, Inc.) or its subsidiary as “X4.” For the periods prior to March 13, 2019, we sometimes refer to the Company as “Arsanis.”

This proxy statement relates to the solicitation of proxies by our board of directors for use at the annual meeting.

On or about May 23, 2019, we intend to begin sending this proxy statement, the attached Notice of Annual Meeting of Stockholders and the enclosed proxy card to all stockholders entitled to vote at the annual meeting.

Although not part of this proxy statement, we are also sending, along with this proxy statement, our 2018 annual report, which includes our financial statements for the fiscal year ended December 31, 2018.

IMPORTANT NOTICE REGARDING THE AVAILABILITY OF PROXY MATERIALS FOR THE

STOCKHOLDER MEETING TO BE HELD ON JUNE 17, 2019

The notice of 2019 annual meeting of stockholders, this proxy statement, our form of proxy card and our 2018 annual report to stockholders are available for viewing, printing and downloading at www.edocumentview.com/XFOR. To view these materials please have your control number(s) available that appear on your proxy card. On this website, you can also elect to receive future distributions of our proxy statements and annual reports to stockholders by electronic delivery. Additionally, you can find a copy of our Annual Report on Form10-K, which includes our financial statements for the fiscal year ended December 31, 2018, on the website of the Securities and Exchange Commission, or the SEC, at www.sec.gov, or in the “SEC Filings” section of the “Investors” section of our website at www.x4pharma.com. You may also obtain a printed copy of our Annual Report on Form 10-K, including our financial statements, free of charge, from us by sending a written request to: Corporate Secretary, X4 Pharmaceuticals, Inc., 955 Massachusetts Avenue, 4th Floor, Cambridge, Massachusetts 02139. Exhibits will be provided upon written request and payment of an appropriate processing fee.

IMPORTANT INFORMATION ABOUT THE ANNUAL MEETING AND VOTING

Why is the Company Soliciting My Proxy?

Our board of directors is soliciting your proxy to vote at the 2019 annual meeting of stockholders to be held at the offices of Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C., on Monday, June 17, 2019, at 10:00 a.m. EDT and any adjournments or postponements of the meeting, which we refer to as the annual meeting. This proxy statement, along with the accompanying Notice of Annual Meeting of Stockholders, summarizes the purposes of the meeting and the information you need to know to vote at the annual meeting.

We have made available to you on the Internet or have sent you this proxy statement, the Notice of Annual Meeting of Stockholders, the proxy card and a copy of our Annual Report on Form10-K for the fiscal year ended December 31, 2018 because you owned shares of our common stock on the record date. We intend to commence distribution of the proxy materials to stockholders on or about May 23, 2019.

Who May Vote?

Only stockholders who owned our common stock at the close of business on April 29, 2019are entitled to vote at the annual meeting. On this record date, there were 12,420,778 shares of our common stock outstanding and entitled to vote. Our common stock is our only class of voting stock.

You do not need to attend the annual meeting to vote your shares. Shares represented by valid proxies, received in time for the annual meeting and not revoked prior to the annual meeting, will be voted at the annual meeting. For instructions on how to change or revoke your proxy, see “May I Change or Revoke My Proxy?” below.

How Many Votes Do I Have?

Each share of ourcommon stock that you own entitles you to one vote.

How Do I Vote?

Whether you plan to attend the annual meeting or not, we urge you to vote by proxy. All shares represented by valid proxies that we receive through this solicitation, and that are not revoked, will be voted in accordance with your instructions on the proxy card or as instructed via the Internet or telephone. You may specify whether your shares should be voted FOR or WITHHELD for the nominee for director, and whether your shares should be voted for, against or abstain with respect to the other proposal. If you properly submit a proxy without giving specific voting instructions, your shares will be voted in accordance with our board of directors’ recommendations as noted below. Voting by proxy will not affect your right to attend the annual meeting. If your shares are registered directly in your name through our stock transfer agent, Computershare Trust Company, N.A., or you have stock certificates registered in your name, you may vote:

By Internet or by telephone. Follow the instructions included in the proxy card to vote over the Internet or by telephone.

By mail. If you received a proxy card by mail, you can vote by mail by completing, signing, dating and returning the proxy card as instructed on the card. If you sign the proxy card but do not specify how you want your shares voted, they will be voted in accordance with our board of directors’ recommendations as noted below.

In person at the meeting. If you attend the meeting, you may deliver a completed proxy card in person or you may vote by completing a ballot, which will be available at the meeting.

Telephone and Internet voting facilities for stockholders of record will be available 24 hours a day and will close at 11:59 p.m. EDT on June 16, 2019.

If your shares are held in “street name” (held in the name of a bank, broker or other holder of record), you will receive instructions from the holder of record. You must follow the instructions of the holder of record in order for your shares to be voted. Telephone and Internet voting also will be offered to stockholders owning shares through certain banks and brokers. If your shares are not registered in your own name and you plan to vote your shares in person at the annual meeting, you should contact your broker or agent to obtain a legal proxy or broker’s proxy card and bring it to the annual meeting in order to vote.

How Does Our Board of Directors Recommend That I Vote on the Proposals?

Our board of directors recommends that you vote as follows:

FOR” the election of the nominee for director; and

FOR” the ratification of the appointment of PricewaterhouseCoopers LLP as our independent registered public accounting firm for our fiscal year ending December 31, 2019.

If any other matter is presented at the annual meeting, your proxy provides that your shares will be voted by the proxy holder listed in the proxy in accordance with his or her best judgment. At the time this proxy statement was first made available, we knew of no matters that needed to be acted on at the annual meeting, other than those discussed in this proxy statement.

May I Change or Revoke My Proxy?

If you give us your proxy, you may change or revoke it at any time before the annual meeting. You may change or revoke your proxy in any one of the following ways:

if you received a proxy card, by signing a new proxy card with a date later than your previously delivered proxy and submitting it as instructed above;

byre-voting by Internet or by telephone as instructed above;

by notifying X4 Pharmaceuticals, Inc.’s Corporate Secretary in writing before the annual meeting that you have revoked your proxy; or

by attending the annual meeting in person and voting in person. Attending the annual meeting in person will not in and of itself revoke a previously submitted proxy. You must specifically request at the annual meeting that it be revoked.

Your most current vote, whether by telephone, Internet or proxy card is the one that will be counted.

What if I Receive More Than One Proxy Card?

You may receive more than one proxy card if you hold shares of our common stock in more than one account, which may be in registered form or held in street name. Please vote in the manner described above under “How Do I Vote?” for each account to ensure that all of your shares are voted.

Will My Shares be Voted if I Do Not Vote?

If your shares are registered in your name or if you have stock certificates, they will not be counted if you do not vote as described above under “How Do I Vote?” If your shares are held in street name and you do not provide voting instructions to the bank, broker or other nominee that holds your shares as described above, the bank, broker or other nominee that holds your shares has the authority to vote your unvoted shares only on the

ratification of the appointment of our independent registered public accounting firm (Proposal 2) without receiving instructions from you. Therefore, we encourage you to provide voting instructions to your bank, broker or other nominee. This ensures your shares will be voted at the annual meeting and in the manner you desire. A “brokernon-vote” will occur if your broker cannot vote your shares on a particular matter because it has not received instructions from you and does not have discretionary voting authority on that matter or because your broker chooses not to vote on a matter for which it does have discretionary voting authority.

What Vote Is Required To Approve Each Proposal and How Are Votes Counted?

Proposal 1: Elect DirectorThe nominee for director who receives the most votes (also known as a “plurality” of the votes cast) will be elected. You may vote either FOR the nominee or WITHHOLD your vote from the nominee. Votes that are withheld will not be included in the vote tally for the election of the director. Brokerage firms do not have authority to vote customers’ unvoted shares held by the firms in street name for the election of the director. As a result, any shares not voted by a customer will be treated as a brokernon-vote. Such brokernon-votes will have no effect on the results of this vote.
Proposal 2: Ratify Appointment of Independent Registered Public Accounting Firm2021  The affirmative vote of the holders of shares of our common stock having a majority in voting power of the votes cast by the holders of all of the shares of our common stock present in person or representedby proxy and entitled to vote at the annual meeting and voting affirmatively or negatively on the matter is required to ratify the appointment of our independent registered public accounting firm. Abstentions will have no effect on the results of this vote. Brokerage firms have authority to vote customers’ unvoted shares held by the firms in street name on this proposal. If a broker does not exercise this authority, such brokerAnnual Meeting.Against
non-votesNot applicable will have no effect on the results of this vote. We are not required to obtain the approval of our stockholders to appoint our independent registered public accounting firm. However, if our stockholders do not ratify the appointment of PricewaterhouseCoopers LLP as our independent registered public accounting firm for 2019, the Audit Committee of our board of directors will reconsider its appointment.(1)

Is Voting Confidential?

We will keep all

(1) Proposal 2 is considered to be a “routine” matter under NYSE rules. Accordingly, if you hold your shares in street name and do not provide voting instructions to your broker, bank or other agent that holds your shares, your broker, bank or other agent has discretionary authority under NYSE rules to vote your shares on this proposal.

What is the proxies, ballots and voting tabulations private. We only let our Inspectorquorum requirement?
A quorum of Election, Computershare Trust Company, N.A.,examine these documents. Management will not know how you voted on a specific proposal unless itstockholders is necessary to meet legal requirements. Wehold a valid meeting. A quorum will however, forward to management any written comments you make on the proxy card or that you otherwise provide.

Where Can I Find the Voting Resultsbe present if stockholdersholdingat 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. On the record date, there were 23,655,660 sharesoutstanding and entitled to vote.Thus, the holders of 11,827,381 shares must be present in person or represented by proxy at the Annual Meeting to have a quorum.

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, bank or other nominee) or if you vote electronically the Annual Meeting. Abstentions and broker non-votes will be counted towards the quorum requirement. If there is no quorum, the 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 can I find out the results of the voting at the Annual Meeting?

The preliminary

Preliminary voting results will be announced at the annual meeting, and weAnnual Meeting. In addition, final voting results will publish preliminary results, or final results if available,be published in a Current Reportcurrent report on Form8-K that we expect to file within four business days ofafter the annual meeting.Annual Meeting. If final voting results are unavailable atnot available to us in time to file a Form 8-K within four business days after the timeAnnual Meeting, we intend to file thea Form8-K then we will file an amended Current Report on Form8-K to disclose the final votingpublish preliminary results and, within four business days after the final voting results are known.

What Areknown to us, file an additional Form 8-K to publish the Costs of Soliciting These Proxies?

We will pay all offinal results.

5



How does the costs of soliciting these proxies. Our directors and employees may solicit proxiesMarch 2019 merger affect the disclosures in person or by telephone, fax or email. We will pay these employees and directors no additional compensation for

these services. We will ask banks, brokers and other institutions, nominees and fiduciaries to forward these proxy materials to their principals and to obtain authority to execute proxies. We will then reimburse them for their expenses.

What Constitutes a Quorum for the Annual Meeting?

The presence, in person or by proxy, of the holders of a majority in voting power of the shares of our common stock issued and outstanding and entitled to vote at the annual meeting is necessary to constitute a quorum at the annual meeting. Votes of stockholders of record who are present at the annual meeting in person or by proxy, abstentions, and brokernon-votes are counted for purposes of determining whether a quorum exists.

Attending the Annual Meeting

The annual meeting will be held at 10:00 a.m. EDT on Monday, June 17, 2019 at the offices of Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C., One Financial Center, Boston, Massachusetts 02111. You need not attend the annual meeting in order to vote.

Householding of Annual Disclosure Documents

SEC rules concerning the delivery of annual disclosure documents allow us or your broker to send a single set of our proxy materials to any household at which two or more of our stockholders reside, if we or your broker believe that the stockholders are members of the same family. This practice, referred to as “householding,” benefits both you and us. It reduces the volume of duplicate information received at your household and helps to reduce our expenses. The rule applies to our annual reports, proxy statements and information statements. Once you receive notice from your broker or from us that communications to your address will be “householded,” the practice will continue until you are otherwise notified or until you revoke your consent to the practice. Stockholders who participate in householding will continue to have access to and utilize separate proxy voting instructions.

If a broker or other nominee holds your shares and (1) your household received a single set of proxy materials this year, but you would prefer to receive your own copy or you do not wish to participate in householding and would like to receive your own set of our proxy materials in future years or (2) you share an address with another stockholder and together both of you would like to receive only a single set of proxy materials, please contact the broker or other nominee directly and inform them of your request. Be sure to include your name, the name of your brokerage firm and your account number.

Electronic Delivery of Company Stockholder Communications

Most stockholders can elect to view or receive copies of future proxy materials over the Internet instead of receiving paper copies in the mail. You can choose this option and save us the cost of producing and mailing these documents by following the instructions provided on your proxy card or by following the instructions provided when you vote over the Internet.

Description of the Merger Completed in March 2019

Prior to March 13, 2019, we were a clinical-stage biopharmaceutical company known as Arsanis, Inc. that had historically been focused on applying monoclonal antibody immunotherapies to address serious infectious diseases. Arsanis was originally incorporated in the State of Delaware in August 2010.

Proxy Statement?

On March 13, 2019, weX4 (formerly Arsanis, Inc.) completed ourits business combination with X4 Therapeutics, Inc. (formerly X4 Pharmaceuticals, Inc.), or X4, in accordance with the terms of anthe Agreement and Plan of Merger, dated as of November 26, 2018, as amended on December 20, 2018 and March 8, 2019, or the Merger Agreement, that we

entered into withby and among X4, X4 Therapeutics, Inc. (formerly X4 Pharmaceuticals, Inc., or “Private X4”) and Artemis AC Corp., a Delaware corporation and our wholly owneda wholly-owned subsidiary or Merger Sub. Pursuant to the terms of the Merger Agreement,Company (the “Merger Sub”), pursuant to which, among other matters, Merger Sub merged with and into Private X4, with Private X4 continuing as our wholly owneda wholly-owned subsidiary of X4 and the surviving corporation of the merger which we refer to as the Merger. At the closing of(the “Merger”). Following the Merger, we issued shares of our common stock toon March 13, 2019, X4 stockholders based on an agreed upon exchange ratio, and each option or warrant to purchase X4 capital stock became an option or warrant, respectively, to purchase our common stock, subject to adjustment in accordance with the agreed upon exchange ratio. Following the closing of the Merger, we effected a6-for-1 1-for-6 reverse stock split of ourits common stock or(the “Reverse Stock Split”), and changed its name to “X4 Pharmaceuticals, Inc.” Following the Reverse Stock Split, our name was changed to X4 Pharmaceuticals, Inc.,completion of the Merger, the business ofconducted by X4 became ourprimarily the business and we becameconducted by Private X4, a clinical-stage biopharmaceutical company focused on the discovery,research, development and commercialization of novel therapeutics for the treatment of rare diseases. In connection with the closing of the Merger, our stock began trading on the Nasdaq Capital Market under the symbol “XFOR” on March 14, 2019. Unless otherwise noted, allAll references to common stock shares and per share amounts and prices per share of common stock in this proxy statementProxy Statement have been retroactively adjusted to reflect, where applicable, the Reverse Stock Split. As used herein, the word “Arsanis” refers to the Company prior to the completion of the Merger.

Split, as indicated.

SECURITY OWNERSHIP

6



PROPOSAL 1
ELECTION OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT

The following table sets forth certain information with respect to the beneficial ownership of our common stock as of April 30, 2019 for (a) the executive officers named in the Summary Compensation Table on page 18 of this proxy statement, (b) each of our directors and director nominees, (c) all of our current directors and executive officers as a group and (d) each stockholder known by us to own beneficially more than 5% of our common stock. Beneficial ownership is determined in accordance with the rules of the SEC and includes voting or investment power with respect to the securities. We deem shares of common stock that may be acquired by an individual or group within 60 days of April 30, 2019 pursuant to the exercise of options or warrants to be outstanding for the purpose of computing the percentage ownership of such individual or group, but those shares are not deemed to be outstanding for the purpose of computing the percentage ownership of any other person shown in the table. Except as indicated in footnotes to this table, we believe that the stockholders named in this table have sole voting and investment power with respect to all shares of common stock shown to be beneficially owned by them based on information provided to us by these stockholders. Percentage of ownership is based on 12,420,778 shares of common stock outstanding on April 30, 2019. Unless otherwise noted below, the address of each stockholder below is c/o X4 Pharmaceuticals, Inc., 955 Massachusetts Avenue, 4th Floor, Cambridge, Massachusetts 02139.

   Number of
Shares
Beneficially
Owned
  Percentage
of Shares
Beneficially
Owned

5% Stockholders

      

Biotechnology Value Fund, L.P. and affiliated entities (1)

    1,295,867    9.99%

Cormorant Asset Management, LP and affiliated entities (2)

    940,387    7.6%

Deerfield Management Company, L.P. and affiliated entities (3)

    847,500    6.7%

FMR LLC and affiliated entities (4)

    1,350,000    10.9%

OrbiMed Advisors LLC and affiliated entities (5)

    1,248,993    9.8%

RA Capital Management, LLC and affiliated entities (6)

    1,243,703    9.99%

Named Executive Officers, Directors and Director Nominees

      

Paula Ragan, Ph.D. (7)

    350,016    2.8%

Adam S. Mostafa

    —      *

Michael Gray, M.B.A., C.P.A. (8)

    84,821    *

David Mantus, Ph.D. (9)

    14,498    *

Christopher Stevens, M.D. (10)

    —      *

Isaac Blech (11)

    70,797    *

Gary J. Bridger, Ph.D.

    —      *

David McGirr (12)

    5,832    *

René Russo, Pharm.D., BCPS (13)

    80,661    *

Murray W. Stewart, M.D.

    —      *

Michael S. Wyzga (14)

    23,441    *

All directors and current executive officers as a group (9 persons) (15)

    625,756    4.9%

*

Represents beneficial ownership of less than 1% of the outstanding shares of our common stock.

(1)

Based on information provided in a Schedule 13G filed by Biotechnology Value Fund, L.P. (“BVF”) on April 23, 2019. Consists of (i) 818,595 shares of common stock, including 450,314 shares of common stock issuable upon the exercise of Class A warrants to purchase common stock held by BVF, (ii) 398,209 shares of common stock, including 100,553 shares of common stock issuable upon the exercise of Class A warrants held by Biotechnology Value Fund II, L.P. (“BVF II”), (iii) 53,140 shares of common stock held by Biotechnology Value Trading Fund OS LP (“Trading Fund OS”), and (iv) 25,923 shares of common stock held by a certain BVF Partners L.P. (“Partners”) managed account (the “Partners Managed Account”). BVF, BVF II, Trading Fund OS and the Partners Managed Account hold Class A warrants andpre-funded warrants to purchase common stock which restrict the exercise of such securities to the extent that such exercises would, (i) in the case of the Class A warrants and thepre-funded warrants, cause the number of shares then beneficially owned by the holder, together with its affiliates and other attribution

DIRECTORS

parties, to exceed 9.99% of the total number of shares of common stock then outstanding, or (ii) in the case of thepre-funded warrants, cause the combined voting power of our securities beneficially owned by the holder, together with its affiliates, to exceed 9.99% of the combined voting power of all of our securities then outstanding immediately after giving effect to the exercise (together, the “Ownership Caps”). As a result of the Ownership Caps, the following have been excluded from the amounts reported above as beneficially owned: (a) 530,425 shares of common stock issuable upon the exercise of pre-funded warrants held by BVF, (b) 263,257 shares of common stock issuable upon the exercise of Class A warrants and 428,704 shares of common stock issuable upon the exercise ofpre-funded warrants held by BVF II, (c) 64,996 shares of common stock issuable upon the exercise of Class A warrants and 76,534 shares of common stock issuable upon the exercise ofpre-funded warrants held by Trading Fund OS, and (d) 31,630 shares of common stock issuable upon the exercise of Class A warrants and 37,337 shares of common stock issuable upon the exercise ofpre-funded warrants held by the Partners Managed Account. BVF Partners OS Ltd. (“Partners OS”), as the general partner of Trading Fund OS, may be deemed to beneficially own the securities beneficially owned by Trading Fund OS. Partners, as the general partner of BVF, BVF II, the investment manager of Trading Fund OS, and the sole member of Partners OS, may be deemed to beneficially own the securities beneficially owned by BVF, BVF II, Trading Fund OS, and the Partners Managed Account. BVF Inc., as the general partner of Partners, may be deemed to beneficially own the securities beneficially owned by Partners. Mark N. Lampert, as a director and officer of BVF Inc., may be deemed to beneficially own the securities beneficially owned by BVF Inc. Partners OS disclaims beneficial ownership of the securities beneficially owned by Trading Fund OS. Each of Partners, BVF Inc. and Mr. Lampert disclaims beneficial ownership of the securities beneficially owned by BVF, BVF II, Trading Fund OS, and the Partners Managed Account. The address of BVF, BVF II, Partners, BVF, Inc. and Mr. Lampert is 44 Montgomery St., 40th Floor, San Francisco, California 94104 and the address of Trading Fund OS and Partners OS is P.O. Box 309 Ugland House, Grand Cayman,KY1-1104, Cayman Islands.
(2)

Based on information provided in a Schedule 13G filed by Cormorant Asset Management, LP on April 22, 2019. Consists of 747,218 shares of common stock held by Cormorant Global Healthcare Master Fund, LP (the “Master Fund”), 114,379 shares of common stock held by Cormorant Private Healthcare Fund I, LP (“Fund I”), and 78,790 shares of common stock held in a managed account (the “Account”). Cormorant Global Healthcare GP, LLC and Cormorant Private Healthcare GP, LLC serve as the general partners of the Master Fund and Fund I, respectively. Cormorant Asset Management, LP serves as the investment manager to the Master Fund, Fund I and the Account. Bihua Chen serves as the managing member of Cormorant Global Healthcare GP, LLC, Cormorant Private Healthcare GP, LLC and the general partner of Cormorant Asset Management, LP. Each of such reporting persons has disclaimed beneficial ownership of such shares except to the extent of its or his pecuniary interest therein. The address of each of such reporting persons is c/o Cormorant Asset Management, LP, 200 Clarendon Street, 52nd Floor, Boston, Massachusetts 02116.

(3)

Based on information provided in a Schedule 13G filed by James E. Flynn on April 16, 2019. Consists of 565,000 shares of common stock and Class A warrants to purchase 282,500 shares of common stock held by Deerfield Special Situations Fund, L.P., of which Deerfield Management Company, L.P. is the investment advisor and Deerfield Mgmt, L.P. is the general partner. James E. Flynn also shares voting and investment control over the securities held by Deerfield Special Situations Fund, L.P. Notwithstanding the number of shares reported, Deerfield Special Situations Fund, L.P., Deerfield Management Company, L.P., Deerfield Mgmt, L.P. and James E. Flynn disclaim beneficial ownership of the shares of common stock issuable upon exercise of such warrants to the extent that upon such exercise the number of shares beneficially owned by Deerfield Special Situations Fund, L.P. and its affiliates, in the aggregate, would exceed the Ownership Cap. The address of Deerfield Special Situations Fund, L.P., Deerfield Management Company, L.P., Deerfield Mgmt, L.P. and James E. Flynn is 780 Third Avenue, 37th Floor, New York, NY 10017.

(4)

Based on information provided in a Schedule 13G filed by FMR LLC on May 10, 2019. Consists of 1,350,000 shares of common stock. Abigail P. Johnson is a Director, the Chairman and the Chief Executive Officer of FMR LLC. Members of the Johnson family, including Abigail P. Johnson, are the predominant owners, directly or through trusts, of Series B voting common shares of FMR LLC, representing 49% of the voting power of FMR LLC. 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 LLC. Neither FMR LLC nor Abigail P. Johnson has the sole power to vote or direct the voting of the shares owned directly by the various investment companies registered under the Investment Company Act (“Fidelity Funds”) advised by Fidelity Management & Research Company (“FMR Co”), a wholly owned subsidiary of FMR LLC, which power resides with the Fidelity Funds’ Boards of Trustees. FMR Co carries out the voting of the shares under written guidelines established by the Fidelity Funds’ Boards of Trustees. The address of FMR LLC is 245 Summer Street, Boston, Massachusetts 02210.
(5)

Based on information provided in a Schedule 13G filed by OrbiMed Advisors LLC (“Advisors”) on April 19, 2019. Consists of 936,493 shares of common stock held by OrbiMed Private Investments IV, LP (“OPI IV”), and 312,500 shares of common stock issuable upon the exercise of Class A warrants to purchase common stock held by OPI IV. Advisors is an investment advisor and is the Managing Member of OrbiMed Capital GP IV LLC (“GP IV”). GP IV is the sole general partner of OPI IV. As a result, Advisors and GP IV share the power to direct the vote and the disposition of the securities held by OPI IV. Advisors exercises this investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho and Jonathan T. Silverstein. On the basis of these relationships, GP IV and Advisors may be deemed to share beneficial ownership of the securities held by OPI IV. The address of Advisors, OPI IV, GP IV, Carl L. Gordon, Sven H. Borho and Jonathan T. Silverstein is 601 Lexington Avenue, 54th Floor, New York, NY 10022.

(6)

Consists of (i) 1,215,000 shares of common stock held by RA Capital Healthcare Fund, L.P. (the “Fund”) and/or a separately managed account (the “Account”), and (ii) 28,703 shares of common stock issuable upon the exercise of Class A warrants to purchase common stock held by the Fund and/or the Account. RA Capital Management, LLC (“RA Capital”) is the general partner of the Fund and serves as investment advisor for the Account. Peter Kolchinsky, Ph.D. is the manager of RA Capital. RA Capital and Dr. Kolchinsky share voting and dispositive power with respect to such securities and may be deemed to beneficially own such securities. As a result of the Ownership Caps, (a) 1,107,297 shares of common stock issuable upon the exercise of Class A warrants held by the Fund and/or the Account, (b) 898,873 shares of common stock issuable upon exercise ofpre-funded warrants held by the Fund, and (c) 158,127 shares of common stock issuable upon the exercise ofpre-funded warrants held by the Account have been excluded from the amounts reported above as beneficially owned. The address of the Fund, RA Capital and Dr. Kolchinsky is c/o RA Capital Management, LLC, 20 Park Plaza, Suite 1200, Boston, MA 02116.

(7)

Consists of 181,366 shares of common stock and 168,650 shares of common stock underlying options held by Dr. Ragan that are exercisable as of April 30, 2019 or will become exercisable within 60 days after such date.

(8)

Mr. Gray is the former President, Chief Executive Officer and Chief Financial Officer of Arsanis. Consists of 41,666 shares of common stock and 43,155 shares of common stock underlying options held by Mr. Gray that are exercisable as of April 30, 2019 or will become exercisable within 60 days after such date.

(9)

Dr. Mantus is the former Chief Development Officer of Arsanis. Consists of 14,498 shares of common stock underlying options held by Dr. Mantus that are exercisable as of April 30, 2019 or will become exercisable within 60 days after such date.

(10)

Dr. Stevens is the former Chief Medical Officer of Arsanis.

(11)

Consists of 70,797 shares of common stock underlying options held by Mr. Blech that are exercisable as of April 30, 2019 or will become exercisable within 60 days after such date.

(12)

Consists of 5,832 shares of common stock underlying options held by Mr. McGirr that are exercisable as of April 30, 2019 or will become exercisable within 60 days after such date.

(13)

Consists of 80,661 shares of common stock underlying options held by Dr. Russo that are exercisable as of April 30, 2019 or will become exercisable within 60 days after such date.

(14)

Consists of 23,441 shares of common stock underlying options held by Mr. Wyzga that are exercisable as of April 30, 2019 or will become exercisable within 60 days after such date.

(15)

See footnotes 7 and 11 through 14 above. E. Lynne Kelley, M.D., our Chief Medical Officer, does not hold any shares of common stock or hold options that are exercisable as of April 30, 2019 or will become exercisable within 60 days after such date.

MANAGEMENT AND CORPORATE GOVERNANCE

Our Board of Directors

Our restated certificate of incorporation, as amended, and our amended and restatedby-laws provide that our business is to be managed by or under the direction of our board of directors. Our board of directors is divided into three classes for purposesclasses. Each class consists, as nearly as possible, of election. Oneone-third of the total number of directors, and each class is elected at each annual meeting of stockholders to serve forhas a three-year term. Our boardVacancies 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, currently consistsshall serve for the remainder of seven members, classified intothe full term of that class and until the director’s successor is duly elected and qualified.

The Board presently has eight members. There are three classes as follows: (1) René Russo and Isaac Blech constitute adirectors in the class with awhose term expiringof office expires at the 2019 annual meeting of stockholders; (2) Gary J. Bridger, Ph.D. and Murray Stewart, M.D. constitute a class with a term ending at the 2020 annual meeting of stockholders; and (3)our Annual Meeting: David McGirr, M.B.A., Paula Ragan, Ph.D. and Michael S. Wyzga constitute a class with a term endingWyzga. If elected at the 2021 annual meetingAnnual Meeting, each of stockholders.

On May 13, 2019, our board of directors accepted the recommendation of our nominating and corporate governance committee and voted to nominate René Russo for election at the annual meeting for a term of three years tothese nominees would serve until the 20222024 annual meeting of stockholders, and until his or her successor has been duly elected and qualified. Mr. Blechqualified, or, if sooner, until the director’s death, resignation or removal. It is our policy that all directors and nominees for director make every effort to attend the Annual Meeting. All of the then-serving directorsattended the 2020 Annual Meeting of stockholders, which was also held in virtual format.

Vote Required
Directors are elected by a plurality of the votes of the holders of shares present in person or represented by proxy and entitled to vote on the election of directors. Accordingly, the three nominees receiving the highest number of affirmative votes will continuebe elected.Shares represented by executed proxies will be voted, if authority to servedo so is not withheld, for the election of the threenominees named below. If any nominee becomes unavailable for election as a director throughresult of an unexpected occurrence, shares that would have been voted for that nominee will instead be voted for the endelection of his term, which concludes at the 2019 annual meeting of stockholders, upon which the number of directors constituting our board of directors will be reduced to six (6).

Set forth below are the names of our directors, including thea substitute nominee proposed by us. Each person nominated for election ashas agreed to serve if elected. We have no reason to believe that any nominee will be unable to serve.

Director Nominees and Continuing Directors
The following is a director and those directors whose terms do not expire this year, their ages, their offices in the Company, if any, their principal occupations or employment for at least the past five years, the length of their tenure as directorsbrief biography and the namesages of other public companies in which such persons hold or have held directorships duringeach nominee and each director whose term will continue after the past five years asAnnual Meeting, and a discussion of April 30, 2019. Additionally, information about the specific experience, qualifications, attributes or skills of each nominee that led the Nominating and Corporate Governance Committee to recommend that person as a nominee for director, as of the date of this Proxy Statement.
There are no family relationships between or among any of our directors or nominees. There is no arrangement or understanding between any of our directors or nominees and any other person or persons pursuant to which he or she is to be selected as a director or nominee.
There are no legal proceedings to which any of our directors is a party adverse to us or any of our subsidiaries or in which any such person has a material interest adverse to us or any of our subsidiaries.
Nominees for Election as a Class I Director for a Three-Year Term Expiring at the 2024 Annual Meeting of Stockholders

David McGirr, M.B.A.age 66, became a member of the board of directors’ conclusion at the timedirectors of filing of this proxy statement that each person listed below shouldArsanis, Inc. in September 2017 and continues to serve as a directormember of our Board following the completion of the Merger in March 2019. From March 2013 until June 2014, Mr. McGirr was Senior Advisor to the chief executive officer of Cubist Pharmaceuticals, Inc., a biopharmaceutical company where he also served as Senior Vice President and Chief Financial Officer from November 2002 to March 2013. Prior to joining Cubist in 2002, Mr. McGirr was the President and Chief Operating Officer of hippo inc., a venture-financed internet technology company. From 1996 to 1999, he was the President of GAB Robins North America, Inc., a risk management company, serving also as Chief Executive Officer from 1997 to 1999. Mr. McGirr was a private equity investor from 1995 to 1996. From 1978 to 1995, Mr. McGirr served in various positions within the S.G. Warburg Group, ultimately as Chief Financial Officer, Chief Administrative Officer and Managing Director of S.G. Warburg & Co., Inc., a position held from 1992 to 1995. Mr. McGirr is set forth below:

Name

Age

Position with the Company

Paula Ragan, Ph.D.

49President, Chief Executive Officer, Secretary and Director

Michael S. Wyzga (1)(3)

64Chairman of the Board of Directors

Isaac Blech (1)(2)

69Director

Gary J. Bridger, Ph.D. (2)(3)

56Director

David McGirr (1)(3)

64Director

René Russo, Pharm.D., BCPS

44Director

Murray W. Stewart, M.D.

58Director

(1)

Member of our audit committee.

(2)

Member of our compensation committee.

(3)

Member of our nominating and corporate governance committee.

currently a member of the board of directors of Insmed Incorporated, a publicly traded biopharmaceutical company, where he has served since October 2013, and Rhythm Pharmaceuticals, Inc., a publicly traded biopharmaceutical company, where he has served since November 2015. Mr. McGirr previously served on the board of directors of Roka Bioscience, Inc., a molecular diagnostics company, from December 2013 to January 2018 and Menlo

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Therapeutics, Inc., a publicly traded biopharmaceutical company, from November 2017 until its merger with Foamix Pharmaceuticals, Ltd., another publicly traded biopharmaceutical company, in March 2019. Mr. McGirr received a B.Sc. in Civil Engineering from the University of Glasgow and received an M.B.A. from The Wharton School at the University of Pennsylvania. We believe that Mr. McGirr’s extensive experience with public and private pharmaceutical companies provides him with the qualifications and skills to serve on our Board.

Paula Ragan, Ph.D. Dr. Ragan, age 51, has beenserved as our President, Chief Executive Officer, Secretary and a member of our board of directors since the closing of the Merger in March 2019. Dr. Ragan has been the President, Chief Executive Officer and a member of the board of directors of X4 since July 2014. She has more than 18 years of experience building companies in the biotechnology industry. FromPrior to joining us, from August 2012 to September 2014, Dr. Ragan consulted as Chief Business Officer at Lysosomal Therapeutics Inc., a private biopharmaceutical company, where she led the company’s business development activities. Prior to that,then, from January 2007 to August 2012, Dr. Ragan held leadership roles in corporate development and operations at Genzyme Corporation, a Sanofi company, where she led strategic partnering efforts for Genzyme’s Rare Disease business and headed the supply chain planning for Genzyme’s flagship commercial products. Other professional roles include business roles at Hydra Biosciences, Oscient Corporation and Celera Corporation. Dr. Ragan received her B.S. from Tufts University and her Ph.D. from Massachusetts Institute of Technology and completed post-doctoral studies at Harvard Medical School. We believe that Dr. Ragan’s perspective and experience as our President and Chief

Executive Officer, which provides the boardBoard with historic knowledge, operational expertise and continuity, provides her with the qualifications and skills to serve on our Board.


Michael S. Wyzga, age 66, 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 and our Chairman following the completion of the Merger in March 2019. 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 Exact Sciences Corporation, a publicly traded medical technology company, where he has served since February 2015; LogicBio Therapeutics, Inc., a publicly traded genetic medicines company, where he has served since September 2018; 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.

Isaac Blech. He previously served at Mereo BioPharma Group plc (formerly Oncomed Pharmaceuticals, Inc.), where he served from October 2013 through the business combination in April 2019 and Akebia Therapeutics, Inc., a publicly traded biopharmaceutical company, from February 2014 to December 2018. He received an M.B.A. from Providence College and a B.S. from Suffolk University. We believe that Mr. BlechWyzga’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.

THE BOARD OF DIRECTORS RECOMMENDS
A VOTE IN FAVOR OF EACH NAMED NOMINEE.


Class II Directors Continuing in Office Until the 2022 Annual Meeting of Stockholders

William E. Aliski, MPA, age 73, has served as a member of our Board since September 2019. Since 2011, Mr. Aliski has served as an independent consultant to life sciences companies focused on orphan diseases. Prior to 2011, he served as Chief Commercial Officer for FoldRX Pharmaceuticals, an early stage company purchased by Pfizer in 2011, served as General Manager for Biomarin Europe, a biopharmaceutical company focused on rare diseases with genetic causes, and held executive level positions at Transkaryotic Therapies (TKT)/Shire and Genzyme Corp., both biopharmaceutical companies. Currently, Mr. Aliski serves as a member of the boards of directors of Ultragenyx Pharmaceutical Inc. and Applied Genetic Therapies Corporation. Mr. Aliski holds a M.P.A. from Harvard University and a Master of Social Planning from Boston College. We believe that Mr. Aliski’s experience, in both consulting and operational roles, with life sciences companies focused on orphan diseases, as well as his public company board experience, qualify him to serve on our Board.

Alison Lawton, age 59, has served as a member of our Board since October 5, 2020. Ms. Lawton currently serves as a special advisor to Kaleido Biosciences, Inc. She most recently served as the President and Chief Executive Officer of Kaleido Biosciences from August 2018 to June 2020, and prior to then as its President and Chief Operating Officer from December
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2017 to August 2018. Prior to joining Kaleido Biosciences, Ms. Lawton served as Chief Operating Officer at Aura Biosciences, Inc., an oncology therapeutics company, from January 2015 until December 2017, and, prior to joining Aura, served as a consultant to Aura from March 2014 to December 2014. Before that, Ms. Lawton served as Chief Operating Officer at OvaScience Inc., a life sciences company, from January 2013 to January 2014. In addition, from 2014 to 2017, Ms. Lawton served as a biotech consultant for various companies, including as a part-time Chief Operating Officer consultant to the Company from 2014 to 2016. Prior to that, Ms. Lawton spent more than 20 years in various positions of increasing responsibility at Genzyme Corporation, a global biopharmaceutical company, and subsequently at Sanofi S.A., also a global biopharmaceutical company, following the acquisition of Genzyme by Sanofi in 2011. Ms. Lawton currently serves as a member of the board of directors of Kaleido Biosciences and ProQR Therapeutics N.V. and has served on those boards since August 2018 and September 2014 respectively. Ms. Lawton previously served as a member of the closingboard of directors of Verastem Inc., from 2012 to 2020, CoLucid Pharmaceuticals, Inc. from 2016 until its acquisition by Eli Lilly in 2017, and Magenta Therapeutics, Inc. from May 2017 to March 2018. She holds a B.Sc. in pharmacology from Kings College, University of London. We believe that Ms. Lawton’s experience as a senior executive in the pharmaceutical and biotechnology industries qualify her to serve on our Board.
René Russo, Pharm.D.age 46, became a member of the board of directors of Arsanis, Inc. in April 2016 and continues to serve as a member of our Board following the completion of the Merger in March 2019. Since May 2019, Dr. Russo has served as the Chief Executive Officer of Xilio Therapeutics (formerly Akrevia Therapeutics), a privately held biopharmaceutical company focused on developing tumor-selective, immuno-oncology therapeutics. Prior to the Merger, Mr. Blechthen, she served as President and Chief Executive Officer of Arsanis, Inc. from April 2016 to November 2018, and as its Chief Development Officer from July 2015 until April 2016. Prior to joining Arsanis, Dr. Russo served in various roles of increasing responsibility over an 11-year period at Cubist Pharmaceuticals, Inc., a memberpublic pharmaceutical development company, focused on the development and commercialization of the X4 board of directors since July 2015. Mr. Blech played a role in establishing some of the world’s leading biotechnology companies, including Celgene Corporation, ICOS Corporation, Pathogenesis Corporation, Nova Pharmaceutical Corporation and Genetics Systems Corporation. These companies are responsible for major advances in oncology, infectious disease therapeutics, from 2003 until its acquisition by Merck in May 2015, most recently as its Vice President, Global Medical Affairs. From 1999 to 2004, she held roles of increasing responsibility at Bristol-Myers Squibb following a Postdoctoral Fellow in Industrial Pharmacy Infectious Diseases. Prior to joining the biotechnology industry, Dr. Russo held clinical positions at Robert Wood Johnson University Hospital and cystic fibrosis. Mr. Blech serves on the boards of directors of Cerecor Inc., ContraFect Corporation, Edge Therapeutics, Inc., SpendSmart Networks, Inc.,Princeton Hospital. Dr. Russo received her Pharm.D. and Aridis Pharmaceuticals Inc. Mr. Blech is also Vice Chairman of a number of private companies including Centrexion Corporation, Alveo Technologies, Elucida Oncology, Nacuity Pharmaceuticals, Sapience Therapeutics, Inc. andX-VAX Technology, Inc. Mr. Blech received his B.A.B.S. from Baruch College.Rutgers University. We believe that Mr. Blech’sDr. Russo’s expertise and experience as a director of numerousan executive at public biotechnology and private pharmaceutical companies provides himand her expertise in clinical development and commercialization of therapeutics targeting infectious diseases, provide her with the qualifications and skills to serve on our Board.

Class III Directors Continuing in Office Until the 2023 Annual Meeting of Stockholders

Gary J. Bridger, Ph.D., age 58, became a member of the board of directors. Asdirectors of the annual meeting, Mr. Blech will no longerX4 Pharmaceuticals, Inc., a private company, in October 2018 and continues to serve as a member of our board of directors.

Gary J. Bridger, Ph.D. Dr. Bridger has served as a member of our board of directors sinceBoard following the closingcompletion of the Merger in March 2019. Prior to the Merger, Dr. Bridger served as a member of the X4 board of directors since October 2018. 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. Bridgerco-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 on the board of directors of Aquinox Pharmaceuticals, Inc., a pharmaceutical company, since 2013. Dr. Bridger2013, has served on the board of directors of Liminal BioSciences Inc., a biotechnology company, since May 2019, and previously served on the board of directors of Alder BioPharmaceuticals, Inc., a biopharmaceutical company, from 2013 to 2016. Dr. Bridger serves on the scientific advisory board of Alectos Therapeutics Inc., a biopharmaceutical company. 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 of directors.

David McGirr, M.B.A. Mr. McGirrBoard.

Murray W. Stewart, M.D., age 60, has served as a member of our board of directors since September 2017. From March 2013 until June 2014, Mr. McGirr was Senior Advisor to the chief executive officer of Cubist Pharmaceuticals, Inc., a biopharmaceutical company where he also served as Senior Vice President and Chief Financial Officer from November 2002 to March 2013. Prior to joining Cubist in 2002, Mr. McGirr was the President and Chief Operating Officer of hippo inc, an internet technology, venture-financed company. From 1996 to 1999, he was the President of GAB Robins North America, Inc., a risk management company, serving also as Chief Executive Officer from 1997 to 1999. Mr. McGirr was a private equity investor from 1995 to 1996. From 1978 to 1995, Mr. McGirr served in various positions within the S.G. Warburg Group, ultimately as Chief Financial Officer, Chief Administrative Officer and Managing Director of S.G. Warburg & Co., Inc., a position held from 1992 to 1995. Mr. McGirr is currently a member of the board of directors of Insmed Incorporated, a publicly traded biopharmaceutical company where he has served since October 2013; Rhythm Pharmaceuticals, Inc., a publicly traded biopharmaceutical company where he has served since November 2015; and Menlo Therapeutics, Inc., a publicly traded biopharmaceutical company where he has served since November 2017. Mr. McGirr also served on the board of directors of Roka Bioscience, Inc., a molecular diagnostics company, from December 2013 to January 2018. Mr. McGirr received a B.Sc. in Civil Engineering from the University of Glasgow and received an M.B.A. from The Wharton School at the University of Pennsylvania. We believe that

Mr. McGirr’s experience as an executive officer or director of a number of public and private pharmaceutical companies provide him with the qualifications and skills to serve on our board of directors.

René Russo, Pharm.D., BCPS. Dr. Russo has served as a member of our board of directors since April 2016 and served as President and Chief Executive Officer of Arsanis from April 2016 to November 2018. Dr. Russo also served as Chief Development Officer of Arsanis from July 2015 until April 2016. Since May 2019, Dr. Russo is serving as the chief executive officer of Akrevia Therapeutics, LLC, a privately held biopharmaceutical company focused on developing immuno-oncology therapeutics. Previously, Dr. Russo served in various roles overan 11-year period at Cubist Pharmaceuticals, Inc., a public pharmaceutical development company, focused on the development and commercialization of infectious disease therapeutics, from 2003 until its acquisition by Merck in May 2015, most recently as its Vice President, Global Medical Affairs. From 1999 to 2004, she held roles of increasing responsibility at Bristol-Myers Squibb where she started her industry career as a Postdoctoral Fellow in Industrial Pharmacy Infectious Diseases. Prior to joining the biotechnology industry, Dr. Russo held clinical positions at Robert Wood Johnson University Hospital and Princeton Hospital. Dr. Russo received her Pharm.D. and B.S. from Rutgers University. We believe that Dr. Russo’s expertise and experience as Arsanis’s former President and Chief Executive Officer, her perspective and experience as an executive at public and private pharmaceutical companies and her expertise in clinical development and commercialization of therapeutics targeting infectious diseases, provide her with the qualifications and skills to serve on our board of directors.

Murray W. Stewart, M.D.Dr. Stewart has served as a member of our board of directorsBoard since March 2019. Dr. Stewart has served as Chief Medical Officer of Rhythm Pharmaceuticals, Inc., a biopharmaceutical company focused on developing and commercializing therapies for the treatment of rare genetic disorders of obesity, since October 2018. He previously served as Head of R&DResearch and Development for Novelion Therapeutics Inc., a biopharmaceutical company focused on developing new standards of care for individuals living with rare disease, where he oversaw global medical affairs for Juxtapid® and Myalept®, two marketed products for rare metabolic diseases, from November 2017 to October 2018. Prior to that, Dr. Stewart washeld various positions of increasing responsibility at GlaxoSmithKline, including serving as Chief Medical Officer at GlaxoSmithKline (GSK),from April 2014 to November 2017, with global responsibility for patient well-being across the vaccine, pharmaceutical, and consumer business units, from April 2014 to November 2017. Duringhis 18-year career at GSK, Dr. Stewartunits. He also held multiple research and development leadership roles, including Chief Medical Officer for the

9


pharmaceutical business, Clinical Head of the Biopharma Unit, and Therapy Area Head for metabolic and cardiovascular diseases. Prior to his tenure with GSK,to joining GlaxoSmithKline, he worked as a consultant physician and honorary senior lecturer at the Diabetes Center in Newcastle upon Tyne in the U.K.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 of directors.

Michael S. Wyzga. Mr. Wyzga has served asBoard.


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INFORMATION REGARDING THE BOARD OF DIRECTORS AND CORPORATE GOVERNANCE
INDEPENDENCEOF THE BOARDOF DIRECTORS
As required under the Nasdaq Stock Market (“Nasdaq”)listing standards, a member of our board of directors since the closingmajority of the Merger in March 2019. Prior to the Merger, Mr. Wyzga served as Chairmanmembers of the X4 board of directors since July 2018. 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. From February 2014 to December 2018, Mr. Wyzga served as a member of the board of directors of Akebia Therapeutics, Inc., a publicly traded biopharmaceutical company, where he was also a member of the compensation committee and chair of the audit committee. Since February 2015, Mr. Wyzga has also served as a member of the board of directors of Exact Sciences Corporation, a publicly traded medical technology company, where he is also a member of the audit and compensation committees. From October 2013 until Oncomed Pharmaceuticals, Inc.’s business combination with Mereo BioPharma Group plc in April 2019, Mr. Wyzga served as a member of the board of directors of Oncomed Pharmaceuticals, Inc., where he was also a member of the audit committee. Since February 2016, Mr. Wyzga has also served as Chairman of the board of directors of GenSight Biologics S.A., a Euronext traded

biopharmaceutical company. Mr. Wyzga also previously served as a member of the board of directors of Idenix Pharmaceuticals, Inc., a publicly traded biotechnology company that was acquired by Merck in August 2014, where he also served as the chair of the audit committee and a member of the compensation committee, and as a member of the Supervisorylisted company’s Board of Prosensa Holding B.V., a publicly traded biopharmaceutical company,Directors must qualify as “independent,” as affirmatively determined by the Board of Directors. The Board consults with its counsel to ensure that the Board’s determinations are consistent with relevant securities and other laws and regulations regarding the definition of “independent,” including those set forth in pertinent listing standards of Nasdaq, as in effect from June 2014 until the Prosensa acquisition by BioMarin Falcon B.V. in December 2014. 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 boardstime to time.

Consistent with these considerations, after review of directors of public companies, and his financial expertise qualify him to serve as a member of our board of directors.

There are no familyall relevant identified transactions or relationships between or among any of our directors or nominee. The principal occupation and employment during the past five years of each of our directors and nominee was carried on, in each case except as specifically identified above, with a corporation or organization that is not a parent, subsidiary or other affiliate of us. There is no arrangement or understanding between any of our directors or nominee and any other person or persons pursuant to which he or she is to be selected as a director, or nominee.

There are no legal proceedings to which any of our directors is a party adverse to us or any of our subsidiarieshis or in which any such personher family members, and the Company, its senior management and its independent auditors, the Board has a material interest adverse to us or anyaffirmatively determined that the following five directors are independent directors within the meaning of our subsidiaries.

Director Independence

Based upon information requested fromthe applicable Nasdaq listing standards: Mr. Aliski, Ms. Lawton, Mr. McGirr, Dr. Stewart and provided by each director concerning their background, employment and affiliations, including family relationships, our board of directors has determinedMr. Wyzga. In making this determination, the Board found that none of Mr. Wyzga, Mr. Blech, Dr. Bridger, Mr. McGirrthese directors or Dr. Stewart, currently representing five out of our seven directors, hasnominees for director had a material or other disqualifying relationship that would interfere with the exercise of independent judgment in carrying out the responsibilities of a director and that each of these directors is “independent” as that term is defined under Rule 5605(a)(2) of the Nasdaq Marketplace Rules.Company. Dr. Ragan is employed by the Companyus and is therefore not independent under Nasdaq Marketplace Rules,listing standards, and Dr. Russo was employed by Arsanisus during the past three years and is therefore not independent under Nasdaq Marketplace Rules. In making such determinations,listing standards. Dr. Bridger provides us with consulting services pursuant to a consulting agreement described under “Transactions with Related Persons and Indemnification – Certain Related-Person Transactions.”

BOARD LEADERSHIP STRUCTURE
The Board has an independent Chairman, Mr. Wyzga, who has authority, among other things, to call and preside over Board meetings, including meetings of the independent directors, to set meeting agendas and to determine materials to be distributed to the Board. Accordingly, the Chairman has substantial ability to shape the work of the Board. We believe that separation of the positions of Chairman and Chief Executive Officer reinforces the independence of the Board in its oversight of our business and affairs. Our Board also recognizes the time, effort and energy that our Chief Executive Officer must devote to her position in the current business environment, as well as the commitment required to serve as our Chairman, particularly as the board of directors considereddirectors’ oversight responsibilities continue to grow. In addition, we believe that having an independent Chairman creates an environment that is more conducive to objective evaluation and oversight of management’s performance, increasing management accountability and improving the relationships that each such nonemployee director or director nominee has with the Company and all other facts and circumstances the board of directors deemed relevant in determining their independence, including the beneficial ownership of our capital stock by each nonemployee director or director nominee.

Committeesability of the Board to monitor whether management’s actions are in the best interests of our Company and our stockholders. As a result, we believe that having an independent Chairman can enhance the effectiveness of the Board as a whole.

ROLEOFTHE BOARDIN 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. In particular, 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.
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 managing important risks that may be faced by us. The Board of Directors

Our board is committed to continuing to ensure and evolve its risk oversight practices as appropriate given the stage of directorsour evolution as a late-stage clinical biopharmaceutical company and the fast-paced changes of the life sciences industry. Regarding the COVID-19 pandemic, our management is meeting regularly to address concerns of our employees and business, as well as updating and communicating

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with the full Board regularly. The full Board has established oversight and has been engaged concerning the monitoring and identification of risks to our Company, and actions we are taking to mitigate risks related to this pandemic.
MEETINGSOF THE BOARDOF DIRECTORS
The Board met seven times during the last fiscal 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 sheserved, held during the portion of the last fiscal year for which he or shewas a director or committee member.


INFORMATION REGARDING COMMITTEESOFTHE BOARDOF DIRECTORS
The Board has three standing committees:an audit committee,Audit Committee, a compensation committeeCompensation Committee and a nominatingNominating and corporate governance committee.Corporate Governance Committee. Each committee operates under a charter approved by our board of directors. Copies of each committee’s charter are posted on the Investors section of our website, which is located at www.x4pharma.com, under the caption “Governance.”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 threemembers: Mr. McGirr (chair), Ms. Lawton and Mr. Wyzga. The Audit Committee met five times during 2020. The Board has adopted a written Audit Committee charter that is available to stockholders on our website at http://investors.x4pharma.com/.
The Audit Committee 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 auditors and sets the compensation of the independence 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, 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; and
reviews our policies and procedures for reviewing and approving related person transactions.
The Board reviews the Nasdaq listing standards definition of independence for Audit Committee members on an annual basis and has determined that all members of the Company’s Audit Committee are independent (as independence is currently defined in Rule 5605(c)(2)(A)(i) and (ii) of the Nasdaq listing standards).
The Board has also determined that each of Mr. McGirr and Mr. Wyzga qualifies as an “audit committee financial expert,” as defined in applicable SEC rules.
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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 Meetings

Duringhas reviewed and discussed the audited financial statements for the fiscal year ended December 31, 2018, there were 19 meetings2020 with management of the board of directors, five meetings of the audit committee, six meetings of the compensation committee and four meetings of the nominating and corporate governance committee. No director attended fewer than 75% of the total number of meetings of the board of directors and of the committee of the board on which he or she served during his or her tenure during fiscal 2018. Dr. Ragan, Mr. Wyzga, Mr. Blech, Dr. Bridger and Dr. Stewart were not elected to our board of directors until the completion of the Merger on March 13, 2019. Our board of directors has adopted a policy that each member of our board of directors make every effort to attend each annual meeting of our stockholders. All except one of Arsanis’s directors attended Arsanis’s annual meeting of stockholders held in 2018.

Company. The Audit Committee. This committee currently has three members, David McGirr (Chairman), Isaac Blech and Michael S. Wyzga. Dr. Murray is expected to become a member ofdiscussed with the audit committee at the annual meeting upon the conclusion of Mr. Blech’s term as a director. Our audit committee’s role and responsibilities are set forth in the audit committee’s written charter and include the authority to retain, terminate and oversee the services of our independent registered public accounting firm. In addition,firm the audit committee reviews annualmatters required to be discussed by the applicable requirements of the Public Company Accounting Oversight Board (“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 considers matters relating to disclosure controlsbe included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2020.

Respectfully submitted,
David McGirr, M.B.A (Chairman)
Alison Lawton
Michael S. Wyzga
Compensation Committee
The Compensation Committee is currently composed of threedirectors: Dr. Stewart (chair), Mr. Aliski and procedures, risk assessment and management and reviews the scope of annual audits.Ms. Lawton. All members of the audit committee satisfy the currentour Compensation Committee are independent (as independence standards promulgated by the Securities and Exchange Commission and byis currently defined in Rule 5605(d)(2) of the Nasdaq Stock Market, as such standards apply specificallyListing Rules.) The Compensation Committee met nine times during 2020. The Board has adopted a written Compensation Committee charter that is available to members of audit committees. Our board of directors has determined that Mr. McGirr and Mr. Wyzga are each an “audit committee financial expert,” as the Securities and Exchange Commission has defined that term in Item 407 of RegulationS-K. Please also see the report of the audit committee set forth elsewhere in this proxy statement.

A copy of the audit committee’s written charter is publicly availablestockholders on our website at www.x4pharma.com.

http://investors.x4pharma.com/.

The Compensation Committee. This committee currently has two members, Isaac Blech (Chairman), and Gary J. Bridger, Ph.D. Dr. Bridger is expected to become Chairman acts on behalf of the Board to review, approve or recommend for approval by the Board and oversee our compensation committeestrategy, policies, plans and Dr. Murray is expectedprograms, including:
review and approval, or review and recommendation to become a memberthe Board for approval,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 Chief Executive Officer and the other executive officers;
oversight of the compensation committee at the annual meeting upon the conclusion of Mr. Blech’s term as a director. Our compensation committee’s role and responsibilities are set forth in the compensation committee’s written charter and includes reviewing, approving and making recommendations regarding our compensation policies, practices and procedures to ensure that legal and fiduciary responsibilitiesevaluation of our boardsenior executives, including determining the nature and frequency of directors are carried out and that such policies, practices and procedures contribute to our success. Our compensation committee also oversees and administers our 2017 Equity Incentive Plan, or 2017 Plan,the evaluation and the X4 2015 Employee, Directorpersons subject to the evaluation, supervising the conduct of the evaluation, and Consultant Equity Incentive Plan, as amended,preparing assessments of the senior executives’ performance;
review and approval or X4 Plan. Thereview and recommendation to the Board of our incentive-compensation and equity-based planes 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 committee is responsible forplans; and
review and recommendation to the reviewing and approving, or making recommendations to our boardBoard with respect to the compensation of our chief executive officerdirector compensation.
Compensation Committee Processes and other senior executive officers, and shall conduct its decision making process with respect to the compensation of our chief executive officer without the chief executive officer present. All members of the compensation committee qualify as independent under the definition promulgated by the Nasdaq Stock Market.

Procedure

In setting base salaries and bonuses and granting equity incentive awards for our executive officers, our compensation committeeCompensation 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. Ragan, as our president and chief executive officer, prepares performance evaluations for the other executive officers and recommends annual salary increases, annual stock option awards and cash bonuses to the compensation committee.Compensation Committee. The compensation committeeCompensation Committee also conducts a performance evaluation of Dr. Ragan. As necessary, the compensation committeeCompensation Committee consults with the board of directorsBoard as to the achievement of corporate objectives that drive contingent compensation awards.

X4 has

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We have utilized Arnosti Consulting, a compensation consultant with expertise in the local biotechnology market to help assess executive and employee compensation and to help inform X4’sour compensation strategy,strategy.
Nominating and we expect to engage a compensation consultant in the future.

Corporate Governance Committee

The processesNominating and procedures followed by Arsanis’s compensation committee in 2018 in consideringCorporate Governance Committeeis current composed of three directors: Mr. Aliski (chair), Mr. McGirr, and determining executive and director compensation are described below under the heading “Executive Officer and Director Compensation—Narrative Disclosure to Summary Compensation Table—Arsanis Compensation.”

A copyMr. Wyzga. All members of the compensation committee’sNominating and Corporate Governance Committee are independent (as independence is currently defined in Rule 5605(a)(2) of the Nasdaq Listing Rules). The Nominating and Corporate Governance Committee met two times during 2020. The Board has adopted a written Nominating and Corporate Governance Committee charter that is publicly available to our stockholders on our website at www.x4pharma.com.

http://investors.x4pharma.com/.

The Nominating and Corporate Governance Committee.This committee currently has three members, Gary J. Bridger, Ph.D. (Chairman), David McGirr and Michael S. Wyzga. Our board of directors has determined that all members of the nominatingBoard is responsible for identifying, reviewing and corporate governance committee, or nominating committee, qualifyevaluating candidates to serve as

independent under directors of the definition promulgatedCompany (consistent with criteria approved by the Nasdaq Stock Market. The nominating committee’s responsibilities are set forth inBoard), reviewing and evaluating incumbent directors, recommending to the nominating committee’s written charter and include:

evaluating andBoardcandidates for election to the Board, making recommendations to the full board asBoard regarding the membership of the committees of the Board (including with respect to making changes or rotation of members, the composition, organizationcreation 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 governance of our board of directors and its committees;

evaluating and making recommendations as to director candidates;

evaluating current board members’ performance;

overseeing the process for CEO and other executive officer succession planning; and

developing and recommending to the Board a set of corporate governance guidelinesprinciples for the Company.

Generally, our nominating committee considers

The Nominating and Corporate Governance Committee believes that candidates for inclusion on the board,director should have certain minimum qualifications, including those recommended by stockholder, in accordance with our Criteriaa reputation for Nomination as a Director appendedintegrity, honesty and adherence to our Corporate Governance Guidelines. Threshold criteria include: personal integrity and high ethical standards,standards; demonstrated business acumen, experience and the ability to exercise sound judgment, independence, knowledgejudgements in matters that relate to the current and long-term objectives of ourthe 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 possible conflictsand 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 diversity,that would impair the extentcandidate’s ability to whichrepresent the candidate would fillinterests of all the Company’s stockholders and to fulfill the responsibilities of a present need on our boarddirector. However, 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 directors,the current composition of the Board, the operating requirements of the Company and concern for the long-term interests of our stockholders. The nominating committee seeksstockholders, and evaluates candidates such that the backgroundsNominating and qualificationsCorporate Governance Committee has direct input from the Chairman of the directors considered as a group provide a significant breadth of experience, knowledgeBoard and abilities that shall assist our board of directors in fulfilling its responsibilities.

the Chief Executive Officer.

Our nominating committeeNominating and Corporate Governance Committee has not adopted a formal diversity policy in connection with the consideration of director nominations or the selection of nominees but believes that our board,Board, taken as a whole, should embody a diverse set of skills, experiences and backgrounds. In this regard, the nominating committeeNominating and Corporate Governance Committee will consider issues of diversity among its members in identifying and considering nominees for director, and strive where appropriate to achieve a diverse balance of backgrounds, perspectives, experience, age, gender, ethnicity and country of citizenship on our board of directors and its committees. The nominating committeeNominating and Corporate Governance Committee does not make any particular weighting of diversity or any other characteristic in evaluating nominees and directors.

If

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 stockholder wishesgroup and individual basis. In the case of new director candidates, the Nominating and Corporate Governance Committee also determines whether the nominee is independent for Nasdaq purposes, which determination is based upon applicable Nasdaq listing standards, applicable SEC rules and regulations and the advice of counsel, if necessary. The Nominating and Corporate Governance Committee then uses its network of contacts to proposecompile a candidate for consideration aslist 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 by majority vote.
The Nominating and Corporate Governance Committee will consider director candidates recommended by stockholders. 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.
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Stockholders who wish to recommend individuals for consideration by the Nominating and Corporate Governance Committee to become nominees for election to our board of directors, it must follow the procedures described in our amended and restatedby-laws and in “Stockholder Proposals and Nominations for Director” at the end of this proxy statement. In general, persons recommendedBoard may do so by stockholders will be considered in accordance with our Criteria for Nomination asdelivering a Director appended to our Corporate Governance Guidelines. Any suchwritten recommendation should be made in writing to the Nominating and Corporate Governance Committee careat 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.
STOCKHOLDER COMMUNICATIONSWITHTHE BOARDOF DIRECTORS
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. Stockholders who wish to communicate with our Board of Directors, or any individual director, may do so by sending written communications addressed to our Corporate Secretary at our principal office and should be accompanied by the following information concerning each recommending stockholder and the beneficial owner, if any, on whose behalf the nomination is made:

all information relating to such person that would be required to be disclosed in a proxy statement;

certain biographical and share ownership information about the stockholder and any other proponent, including a description of any derivative transactions in the Company’s securities;

a description of certain agreements, arrangements and understandings between or among the proposing stockholder and any beneficial owner and any other person in connection with such stockholder nomination and the director nominee; and

a statement whether such stockholder or beneficial owner intends to appear in person or by proxy at the meeting to nominate the person(s) named in its notice; and

a statement whether or not either such stockholder or beneficial owner intends to deliver a proxy statement and form of proxy to holders of voting shares sufficient to carry the proposal.

The recommendation must also be accompanied by the following information concerning the proposed nominee:

certain biographical information and share ownership information concerning the proposed nominee;

all information concerning the proposed nominee required to be disclosed in solicitations of proxies for election of directors;

all information concerning compensation or other material monetary agreements, arrangements or understandings during the past three years and any other material relationship between or among the stockholder, beneficial owner and their respective affiliates and each proposed nominee, and his or her affiliates; and

a description of all relationships between the proposed nominee and the recommending stockholder or any beneficial owner, including any agreements or understandings regarding the nomination.

A copy of the nominating committee’s written charter is publicly available on our website at www.x4pharma.com.

Board Leadership Structure and Role in Risk Oversight

The positions of our chairman of the board and chief executive officer are separate. Separating these positions allows our chief executive officer to focus on ourday-to-day61 North Beacon Street, business, while allowing the chairman of the board to lead the board of directors in its fundamental roles of setting a company’s overall strategy and providing advice to and independent oversight of management. Our board of directors recognizes the time, effort and energy that the chief executive officer must devote to her position in the current business environment, as well as the commitment required to serve as our chairman, particularly as the board of directors’ oversight responsibilities continue to grow. Our board of directors also believes that this structure ensures a greater role for the independent directors in the oversight of the company and active participation of the independent directors in setting agendas and establishing priorities and procedures for the work of our board of directors. Our board of directors believes its administration of its risk oversight function has not affected its leadership structure.

Although our bylaws do not require the chairman and chief executive officer positions to be separate, our board of directors believes that having separate positions is the appropriate leadership structure for the Company at this time and demonstrates our commitment to good corporate governance.

Risk is inherent with every business, and how well a business manages risk can ultimately determine its success. Our board of directors is actively involved in oversight of risks that could affect the Company. This oversight is conducted primarily by our full board of directors, which has responsibility for general oversight of risks. 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 of directors 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 of directors receives reports by each committee chair regarding the committee’s considerations and actions. In particular, 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 financial risk, including our internal control over financial reporting. 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.

At each of its meetings, the board of directors 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 of directors provides guidance to management. Our board of directors believes that full and open communication between management and the board of directors is essential for effective risk management and oversight.

Stockholder Communications to our Board of Directors

Generally, stockholders who have questions or concerns should contact our Investor Relations department at (857)529-8300. However, any stockholders who wish to address questions regarding our business directly with our board of directors, or any individual director, should direct his or her questions in writing to the chairman of our board of directors at 955 Massachusetts Avenue,4th Floor, Cambridge,Boston, Massachusetts 02139.

02134.

Communications will be distributed to our boardBoard of directors,Directors, 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 boardBoard of directorsDirectors 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.

Executive Officers

CODEOF ETHICS
We have adopted aCode 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 http://investors.x4pharma.com.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.

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PROPOSAL 2
RATIFICATIONOF SELECTIONOF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM
The Audit Committee of the Board has selected PricewaterhouseCoopers LLP as our independent registered public accounting firm for the fiscal year ending December 31, 2021 and has further directed that management submit the selection of its independent registered public accounting firm for ratification by the stockholders at the Annual Meeting. PricewaterhouseCoopers LLP has audited our financial statements since 2016 and also served as our auditor when we were a private company since 2016. Representatives ofPricewaterhouseCoopers LLP are expected to be present at the Annual Meeting. They will have an opportunity to make a statement if they so desire and will be available to respond to appropriate questions.
Neither our Bylaws nor other governing documents or law require stockholder ratification of the selection of PricewaterhouseCoopers LLP as our independent registered public accounting firm. However, the Audit Committee of the Board is submitting the selection of PricewaterhouseCoopers LLP to the stockholders for ratification as a matter of good corporate practice. If the stockholders fail to ratify the selection, the Audit Committee of the Board will reconsider whether or not to retain that firm. Even if the selection is ratified, the Audit Committee of the Board in its discretion may direct the appointment of different independent auditors at any time during the year if they determine that such a change would be in our best interests and our stockholders.
PRINCIPAL ACCOUNTANT FEESAND SERVICES
The following table represents aggregate fees billed to us for the fiscal years ended December 31, 2020 and December 31, 2019 by PricewaterhouseCoopers LLP, our principal accountant.
   For the year ended
   2020  2019
Audit Fees(1)
  $1,102,700   $1,422,363 
Audit-related Fees(2)
  —   — 
Tax Fees(3)
  —   10,000 
All Other Fees (4)
  2,756   2,400 
Total Fees  $1,105,456   $1,434,763 
(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 2020 Audit Fees are fees of $385,000 in connection with the filing of registration statements and issuance of comfort letters. Included in 2019 Audit Fees are fees of $762,363 in connection with filing of registration statements.
(2)Consist of fees billed by an independent registered public accounting firm for assurance and related services that are reasonably related to the performance of the audit or review of financial statements and which are not reported under “Audit Fees.” There were no such fees incurred in 2020 or 2019.
(3)Consists of fees billed for tax compliance, tax advice and tax planning services, including the review and preparation of federal and state income tax returns.
(4)Consists of subscription fees paid for access to online accounting research software applications and data.
All fees described above were pre-approved by the Audit Committee. There were no services that were approved by the Audit Committee pursuant to Rule 2-01(c)(7)(i)(C) (relating to the approval of a de minimis amount of non-audit services after the fact but before completion of the audit).
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, PricewaterhouseCoopers LLP. 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
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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 the 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 Audit Committee has determined that the rendering of services other than audit services by PricewaterhouseCoopers LLP is compatible with maintaining the principal accountant’s independence.
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 ratify the selection of PricewaterhouseCoopers LLP.
THE BOARDOF DIRECTORS RECOMMENDS
A VOTEIN FAVOROF PROPOSAL 2.

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EXECUTIVE OFFICERS

The following table sets forth certain information as of April 30, 2019 regarding each ofwith respect to our executive officers whoand their ages as of the date of this Proxy Statement. There are not also directors. We have employment agreements with allno family relationships between any of our executive officers, and all of ourthere is no arrangement or understanding between any executive officers areat-will employees.

officer and any other person pursuant to which the executive officer was selected.

Name

  Age  

Position

Paula Ragan, Ph.D.

51President, Chief Executive Officer, Corporate Secretary and Director
Adam S. Mostafa

  3941  Chief Financial Officer and Treasurer

E. Lynne Kelley

Diego Cadavid, M.D.
5556Chief Medical Officer
Arthur Taveras, Ph.D.57Chief Scientific Officer
Derek Meisner, J.D.50General Counsel



Paula Ragan, Ph.DBiographical information for Dr. Ragan is presented above under the caption “Nominees for Election as a Class I Director for a Three-Year Term Expiring at the 2024 Annual Meeting of Stockholders”
Adam S. Mostafa. Mr. Mostafa has served as our Chief Financial Officer and Treasurer since the closing of the Merger in March 2019. Prior to the Merger, Mr. Mostafa served as Private X4’s Chief Financial Officer since September 2018. Prior to joining Private X4, Mr. Mostafa served as chief financial officer of Abpro Corporation, a biotechnology company focused on antibody therapeutics, from June 2016 to August 2018. Prior to that, Mr. Mostafa was a managing director in the healthcare investment banking group at Cantor Fitzgerald from January 2015 to May 2016, and from June 2011 to January 2015, Mr. Mostafa was a senior banker in the healthcare investment banking group at Needham & Company. Prior to that, Mr. Mostafa was a vice president in the investment banking group at CRT Capital Group from March 2007 to May 2011, and from September 2003 to March 2007, Mr. Mostafa was a portfolio management associate in the global stock selection group at AQR Capital. Mr. Mostafa began his career as an analyst in the healthcare investment banking group at Salomon Smith Barney. Mr. Mostafa earned an A.B. in Economics from Brown University.

E. Lynne Kelley,


Diego Cadavid, M.D.Dr. KelleyCadavid has served as our Chief Medical Officer since April 2019. She brings more thanDecember 2020. Previously, from September 2016 to November 2020, Dr. Cadavid was Vice President of Clinical Development and then Senior Vice President and Head of Clinical Development at Fulcrum Therapeutics, a decadepublic biopharmaceutical company. Dr. Cadavid served in various roles of experience directing clinical developmentincreasing responsibility at Biogen from 2008 until September 2016, ultimately departing as Senior Medical Director, Multiple Sclerosis Clinical Development Group. From 2008 until 2015, Dr. Cadavid was also a consultant at the Center for Immunology and global expansion of novel pharmaceutical productsInflammatory Diseases at both emerging and established life sciences companies. Dr. KelleyMassachusetts General Hospital. He is a Board Certified Generallicensed physician and Vascular Surgeon. Before joininga board-certified neurologist. Additionally, Dr. Cadavid has served as an Affiliate Instructor in Neurology at the University of Massachusetts Medical School since May 2018, and he previously taught at the Rutgers-New Jersey Medical School for 9 years. Dr. Cadavid received undergraduate and graduate medical education at Pontificia Universidad Javeriana in Colombia, and conducted his post-doctoral fellowship training and residency training at the University of Texas Health Science Center, the Armed Forces Institute of Pathology, and Georgetown University Medical Center and Affiliated Hospitals.

Arthur Taveras, Ph.D. Dr. Taveras has served as our company, Dr. Kelley was chief medical officer (CMO) of Massachusetts-based biopharmaceutical company Histogenics CorporationChief Scientific Officer since November 2020. Previously, from JulyAugust 2018 to January 2019, where she led the development of restorative cell therapies to replace damaged cartilage and oversaw the completion of a Phase 3 clinical trial and regulatory submission for the company’s lead program. Previously, from January 2016 to May 2018,July 2020, Dr. KelleyTaveras served as CMOChief Scientific Officer of Senseonics Holdings,Comet Therapeutics, Inc., a private biotechnology company. From May 2015 to the present, Dr. Taveras has served in various capacities as Chief Scientific Officer, Head of Drug Discovery and/or Owner of Transform Therapeutics, a private company he founded that developsis focused on developing novel therapeutics for cancer, neurodegenerative diseases and sells systemsimmunologic disorders. Dr. Taveras also served as President & Chief Scientific Officer of Shanghai ChemPartner Co., Ltd., a research organization serving the pharmaceutical and biotechnology industry, from October 2013 to help people with diabetes monitor their glucose levels. She alsoDecember 2014. Earlier in his career, he held leadership positions in clinical development roles at global companies such as Becton, Dickinson and Company, a global medical technology company (from January 2011 to December 2015), Kimberly-Clark Corporation, a company focused on creating essential household products (from January 2008 to December 2011)Biogen, Atlantos Pharmaceuticals (later acquired by Amgen), and Boston Scientific Corporation, a medical device company (from November 2005 to December 2008)Schering-Plough Research Institute (later acquired by Merck). Dr. KelleyTaveras received her medical degreehis Ph.D., M.S and B.S. degrees from Dartmouth Medical SchoolRensselaer Polytechnical Institute.
Derek MeisnerJ.D. Mr. Meisner has served as our General Counsel since November 2019. From September 2018 until October 2019, Mr. Meisner held the role of General Counsel at Genocea Biosciences, a publicly traded, clinical-stage
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biopharmaceutical company. Prior to Genocea, he served as General Counsel of multiple Boston-based financial services firms, including Quantopian, Inc., a venture-backed start-up, from April 2016 until September 2018, and her bachelor’s degreelife science investor RA Capital Management from January 2015 to April 2016. Mr. Meisner was also previously a partner at the international law firm K&L Gates and Branch Chief in biology from Boston University. She trained at Dartmouth Hitchcock Hospital and Massachusetts General Hospital, and was a practicing surgeon at Yale University. Dr. Kelley was named Fellowthe Division of Enforcement of the AmericanU.S. Securities and Exchange Commission.
Mr. Meisner holds a B.A. from the University of Michigan and a J.D. from the Washington College of Surgeons, was awarded an NIH research grantLaw at Harvard UniversityAmerican University.

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SECURITY OWNERSHIP OF
CERTAIN BENEFICIAL OWNERS AND MANAGEMENT
The following table sets forth certain information regarding the ownership of the Company’s common stock as of April 5, 2021 by: (i) each director and nominee for director; (ii) each of the executive officers named in the Summary Compensation Table; (iii) all current executive officers and directors of the Company as a group; and (iv) all those known by the Company to be beneficial owners of more than five percent of its common stock. Applicable percentages are based on 23,655,660 shares outstanding on April 5, 2021, adjusted as required by rules promulgated by the SEC. Unless otherwise noted below, the address of each stockholder below is c/o X4 Pharmaceuticals, Inc., 61 North Beacon Street, 4th Floor, Boston, Massachusetts 02134.
   
Beneficial Ownership (1)
 
Beneficial Owner  Number of Shares   Percent of Total 
5% Stockholders    
Entities affiliated with Ikarian Capital, LLC (1)
2,624,98811.10 %
Entities affiliated with Biotechnology Value Fund L.P. (2)
2,625,7269.99 %
Entities affiliated with RA Capital Management, L.P. (3)
2,565,9629.99 %
Entities affiliated with Bain Capital Life Sciences Fund, L.P (4)
   2,390,240    9.99 %
Entities affiliated with OrbiMed Advisors LLC (5)
   1,835,993    7.61 %
Named Executive Officers, Directors and Director Nominees    
Paula Ragan, Ph.D. (6)
   288,812    1.91 %
Adam S. Mostafa (7)
   50,653    *
Derek Meisner (7)
   21,771    *
William E. Aliski (7)
   7,235    *
Gary J. Bridger, Ph.D (7)
   23,740    *
Alison Lawton— — 
David McGirr, M.B.A (7)
   12,686    *
René Russo, Pharm.D. (7)
   87,515    *
Murray W. Stewart, M.D. (7)
   8,377    *
Michael S. Wyzga (7)
   73,032    *
All directors and current executive officers as a group (12 people) (8)
   742,628    3.06 %
*Less than one percent.
(1) Based on a Schedule 13G filed on April 8, 2021. Consists of shares held by by Ikarian Capital, LLC (“Ikarian Capital”), Ikarian Healthcare Master Fund, L.P, (the “Ikarian Fund”), Ikarian Healthcare Fund GP, L.P., (“Ikarian GP”), Chart Westcott and Neil Shahrestani (such individuals, together with Ikarian Capital, Ikarian Fund and Ikarian GP, the “Ikarian Parties”). The Ikarian Fund and the Marco Polo Fellowship studying at Hospital Henri MondorIkarian Managed Accounts are the record and direct beneficial owners of the University Paris Hospital System,shares of common stock. Ikarian Capital is the investment manager of, and may be deemed to indirectly beneficially own securities owned by, the Ikarian Fund. Ikarian GP is the general partner of, and may be deemed to indirectly beneficially own securities owned by, the Fund. Ikarian Capital is also the general partner of, and may be deemed to indirectly beneficially own, securities beneficially owned by Ikarian GP. Ikarian Capital is a sub-advisor for certain separate managed accounts (collectively, the “Ikarian Managed Accounts”) and may be deemed to indirectly beneficially own securities owned by the Ikarian Managed Accounts. Ikarian Capital is ultimately owned and controlled by Chart Westcott Living Trust, of which Mr. Westcott serves as the sole trustee (the “Westcott Trust”), and indirectly by Mr. Shahrestani. Accordingly, each of Mr. Westcott, as sole trustee of the Westcott Trust, and Mr. Shahrestani may be deemed to indirectly beneficially own securities beneficially owned by Ikarian Capital. The Ikarian Fund disclaims beneficial ownership of the shares held by the Ikarian Managed Accounts. The address of the Ikarian Parties is c/o Ikarian Capital, LLC, 100 Crescent Court, Suite 1620, Dallas, Texas 75201.

(2) Based in part on information provided in a Schedule 13G/A filed by entities affiliated with Biotechnology Value Fund, L.P. (“BVF”) on February 16, 2021. Consists of (i) 448,467 shares of common stock held by BVF, 293,248 shares of common stock held by Biotechnology Value Fund II, L.P. (“BVF II”), and 48.836 shares of common stock held by Biotechnology Value Trading Fund OS LP (“Trading Fund OS”), (ii) 530,425 shares of common stock issuable upon the exercise of pre-funded warrants issued in April 2019 (“April Pre-Funded Warrants”) held by BVF, 428,704 shares of common stock issuable upon the exercise of April Pre-Funded Warrants held by BVF 2, 76,534 shares of common stock issuable upon the exercise of April Pre-Funded Warrants held by Trading Fund OS, and 37,377 shares of common stock issuable upon the exercise of April Pre-Funded Warrants held by a certain BVF Partners L.P. (“Partners”) managed account (the “Partners Managed Account”), (iii) 69,814 shares of common stock issuable upon the exercise of Class A warrants to purchase common stock (“Class A Warrants”) held by BVF, 64,996 shares of common stock issuable
20


upon the exercise of Class A Warrants held by Trading Fund OS, and 31,630 shares of common stock issuable upon the exercise of Class A Warrants held by the Partners Managed Account, (iv) 259,739 shares of common stock issuable upon the exercise of pre-funded warrants issued in November 2019 (the “November Pre-Funded Warrants”) held by BVF, 204,465 shares of common stock issuable upon the exercise of November Pre-Funded Warrants held by BVF 2, and 35,796 shares of common stock issuable upon the exercise of November Pre-Funded Warrants held by Trading Fund OS, and (v) 66,236 shares of common stock issuable upon the exercise of Class B warrants to purchase common stock (“Class B Warrants”) held by Trading Fund OS and 29,459 shares of common stock issuable upon the exercise of Class B Warrants held by the Partners Managed Account. Each of the April Pre-Funded Warrants, the Class A Warrants, the November Pre-Funded Warrants, and the Class B Warrants contain provisions that restrict the exercise of such securities to the extent that such exercises would, (i) in the case of the Class A warrants, Class B warrants, the April Pre-Funded Warrants and the November Pre-Funded warrants, cause the number of shares then beneficially owned by the holder, together with its affiliates and other attribution parties, to exceed 9.99% of the total number of shares of common stock then outstanding, or (ii) in the case of the April Pre-Funded Warrants and the November Pre-Funded Warrants, cause the combined voting power of our securities beneficially owned by the holder, together with its affiliates, to exceed 9.99% of the combined voting power of all of our securities then outstanding immediately after giving effect to the exercise (together, the “Ownership Caps”). As a result of the Ownership Caps, the following have been excluded from the amounts reported above as beneficially owned: (a) 380,500 shares of common stock issuable upon the exercise of Class A Warrants held by BVF and 363,810 shares of common stock issuable upon the exercise of Class A Warrants held by BVF 2 and (b) 518,856 shares of common stock issuable upon the exercise of Class B Warrants held by BVF and 385,449 shares of common stock issuable upon the exercise of Class B Warrants held by BVF 2. BVF Partners OS Ltd. (“Partners OS”), as the general partner of Trading Fund OS, may be deemed to beneficially own the securities beneficially owned by Trading Fund OS. Partners, as the general partner of BVF, BVF II, the investment manager of Trading Fund OS, and the sole member of Partners OS, may be deemed to beneficially own the securities beneficially owned by BVF, BVF II, Trading Fund OS, and the Partners Managed Account. BVF Inc., as the general partner of Partners, may be deemed to beneficially own the securities beneficially owned by Partners. Mark N. Lampert, as a director and officer of BVF Inc., may be deemed to beneficially own the securities beneficially owned by BVF Inc. Partners OS disclaims beneficial ownership of the securities beneficially owned by Trading Fund OS. Each of Partners, BVF Inc. and Mr. Lampert disclaims beneficial ownership of the securities beneficially owned by BVF, BVF II, Trading Fund OS, and the Partners Managed Account. The address of BVF, BVF II, Partners, BVF, Inc. and Mr. Lampert is 44 Montgomery St., 40th Floor, San Francisco, California 94104 and the address of Trading Fund OS and Partners OS is P.O. Box 309 Ugland House, Grand Cayman, KY1-1104, Cayman Islands.

(3) Based in part on a Schedule 13G/A filed by RA Capital Management, L.P. (“RA Capital”), Peter Kolchinsky, and Rajeev Shah on February 16, 2021. Consists of (i) 536,962 shares of common stock held by RA Capital Healthcare Fund, L.P. (the “RA Fund”), (iii) 898,873 shares of common stock issuable upon the exercise of April Pre-Funded Warrants held by the Fund, (iii) 158,127 shares of common stock issuable upon the exercise of April Pre-Funded Warrants held by the Account, (iv) 966,054 shares of common stock issuable upon the exercise of Class A Warrants held by the Fund and (v) 5,946 shares of common stock issuable upon the exercise of Class A Warrants held by the account. As a result of the Ownership Caps, 164,000 shares of common stock issuable upon the exercise of Class A Warrants held by the RA Fund have been excluded from amounts reported above as beneficially owned. RA Capital Healthcare Fund GP, LLC is the general partner of the RA Fund. The general partner of RA Capital is RA Capital Management GP, LLC, of which Dr. Kolchinsky and Mr. Shah are the controlling persons. RA Capital serves as investment adviser for the RA Fund and the Account and may be deemed a beneficial owner of any securities held by the Fund and the Account. The RA Fund has authored numerous articlesdelegated to RA Capital the sole power to vote and the sole power to dispose of all securities held in the Fund’s portfolio, including the shares of our common stock. Because the RA Fund has divested voting and investment power over the shares of our securities it holds and may not revoke that delegation on less than 61 days’ notice, the RA Fund disclaims beneficial ownership of our securities it holds. As managers of RA Capital, Dr. Kolchinsky and Mr. Shah may be deemed beneficial owners of our securities beneficially owned by RA Capital. RA Capital, Dr. Kolchinsky, and Mr. Shah disclaim beneficial ownership of our securities. The address of the RA Fund, RA Capital and Dr. Kolchinsky is c/o RA Capital Management, LLC, 200 Berkley Street, 18th Floor, Boston, MA 02116.

(4) Based in part of a Schedule 13G filed by Bain Capital Life Sciences Fund, L.P. (“BCLS”), Bain Capital Life Sciences Fund II, L.P. (“BCLS II”), and BCIP Life Sciences Associates, LP, (“BCIP LS” and, together with BCLS and BCLS II, the “Bain Capital Holders”) on December 9, 2019. Consists of (i) 566,966 shares of common stock and 270,700 shares of common stock issuable upon exercise of November Pre-Funded Warrants held by BCLS, (ii) 1,332,276 shares of common stock held by BCLS II, and (iii) 220,298 shares of common stock held by BCIP LS. As a result of the Ownership Caps and similar ownership limitations included in certain prefunded warrants to purchase common stock issued in March 2021 (the “March Pre-Funded Warrants), the following have been excluded from the amounts reported above as beneficially owned: (a) 296,266 shares of common stock issuable upon exercise of November Pre-Funded Warrants and 1,133,932 shares of common stock issuable upon exercise of Class B Warrants held by BCLS, (b) 557,143 shares of common stock issuable upon exercise of November Pre-Funded Warrants, 1,114,285 shares of common stock issuable upon exercise of Class B Warrants, and 44,571 shares of common stock issuable upon exercise of March Pre-Funded Warrants held by BCLS II, and (c) 125,891 shares of common stock issuable upon exercise of November Pre-Funded Warrants, 251,782 shares of common stock issuable upon exercise of Class B Warrants, and 5,429 shares of common stock issuable upon exercise of March Pre-Funded Warrants held by BCIP LS. Bain Capital Life Sciences Investors, LLC, (“BCLSI”), whose managers are Jeffrey Schwartz and Adam Koppel, is (i) the general partner of Bain Capital Life Sciences Partners, LP, a Cayman exempted limited partnership (“BCLSP”), which is the general partner of BCLS and (ii) the manager of Bain Capital Life Sciences Investors II, LLC, (“BCLSI II”), which is the general partner of BCLS II. Boylston Coinvestors, LLC, a Delaware limited liability company (“Boylston”), is the general partner of BCIP LS. BCLSI governs the investment strategy and decision-making process with respect to investments held by BCIP LS. As a result, each of BCLSI, Mr. Schwartz and Dr. Koppel may be deemed to share voting and dispositive power with respect to the securities held by the Bain Capital Holders. The address of each of the Bain Capital Holders, BCLSI, BCLSP, BCLSI II, Boylston, Mr. Schwartz and Dr. Koppel is 200 Clarendon Street, Boston, MA 02116.

21


(5) Based on a Schedule 13G/A filed by OrbiMed Advisors LLC (“Advisors”) on March 25, 2021. Consists of 1,373,493 shares of common stock held by OrbiMed Private Investments IV, LP (“OPI IV”), and 462,500 shares of common stock issuable upon the exercise of Class A and Class B warrants to purchase common stock held by OPI IV. Advisors is an investment advisor and is the Managing Member of OrbiMed Capital GP IV LLC (“GP IV”). GP IV is the sole general partner of OPI IV. As a result, Advisors and GP IV share the power to direct the vote and the disposition of the securities held by OPI IV. Advisors exercises this investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho and Jonathan T. Silverstein. On the basis of these relationships, GP IV and Advisors may be deemed to share beneficial ownership of the securities held by OPI IV. The address of Advisors, OPI IV, GP IV, Carl L. Gordon, Sven H. Borho and Jonathan T. Silverstein is 601 Lexington Avenue, 54th Floor, New York, NY 10022.

(6) Consists of 168,809 shares of common stock, 274,828 shares of common stock underlying options that were exercisable as of April 5, 2021 or will become exercisable within 60 days after such date, and 13,982 shares of common stock underlying restricted stock units that were vested as of April 15, 2021 or will become exercisable within 60 days after such date.

(7) Consists of shares of common stock underlying options that were exercisable as of April 5, 2020 or will become exercisable within 60 days after such date.

(8) Consists of 168,809 shares of common stock, 559,837 shares of common stock underlying options that were exercisable as of April 15, 2020 or will become exercisable within 60 days after such date, and 13,982 shares of common stock underlying restricted stock units that were vested as of April 5, 2020 or will become exercisable within 60 days after such date.




22


EXECUTIVE COMPENSATION

Our Compensation Committee is primarily responsible for peer-reviewed publications.

establishing and reviewing our general compensation strategy, see the section captioned “Compensation Committee Processes and Procedure.”

EXECUTIVE OFFICER AND DIRECTOR COMPENSATION

Summary Compensation Table

SUMMARY COMPENSATION TABLE

The following table shows the total compensation paid or accrued during the fiscal years ended December 31, 20182020 and December 31, 20172019 to (1) the individualsindividual who served as our Chief Executive Officer during the fiscal year ended December 31, 2018,2020 and (2) our two next most highly compensated executive officers who earned more than $100,000 during the fiscal year ended December 31, 20182020 and were serving as executive officers as of such date, and (3) any individualdate. We refer to these individuals in this Proxy Statement as our Named Executive Officers.
Our Named Executive Officers for 2020 who would otherwise be includedappear in (2) above but for the fact that such individual was not serving as an executive officer of ours as of December 31, 2018. The Summary Compensation Table includes Michael Gray, M.B.A., C.P.A., David Mantus, Ph.D., and Christopher Stevens, M.D., each of whom resigned from their respective positions in connection with the Merger, and René Russo, Pharm.D., BCPS, who resigned from her positions as of November 26, 2018. In addition, we have also included are:
Paula Ragan, Ph.D., our current President, Chief Executive Officer, Corporate Secretary and Secretary following the Merger, and Director;
Adam S. Mostafa, our current Chief Financial Officer and Treasurer following the Merger, in the table below, notwithstanding that such persons did not serve as executive officers of the Company during the fiscal year ended December 31, 2018. These executive officers are referred to as our “named executive officers” in this proxy statement.

Name and Principal Position (1)

 Year Salary
($)
 Bonus
($) (2)
 Stock
Awards
($) (3)
 Option
Awards
($) (3)
 Non-equity
Incentive Plan
Compensation
($) (4)
 All Other
Compensation
($) (5)
 Total ($)

Paula Ragan, Ph.D.

   2018   380,000   —     —     407,577   133,000   450   921,027

President, Chief Executive

Officer and Secretary

   2017   364,000   —     —     303,422   89,180   576   757,178
                

Adam S. Mostafa (6)

   2018   109,285   —     —     480,789   38,250   90   628,414

Chief Financial Officer and

Treasurer

                

Michael Gray, M.B.A., C.P.A.

   2018   405,193   181,136   1,030,000   1,310,947   —     —     2,927,276

Former President, Chief

Executive Officer and Chief

Financial Officer

   2017   363,077   231,525   —     262,090   —     —     856,692
                
                

David Mantus, Ph.D.

   2018   358,750   —     —     595,885   —     120,250   1,074,885

Former Chief Development

Officer

   2017   313,750   —     —     117,926   —     —     431,676
                

René Russo, Pharm.D., BCPS

   2018   405,866   —     —     1,906,833   —     1,046,250   3,358,949

Former President and Chief

Executive Officer

   2017   388,750   254,100   —     524,182   —     —     1,167,032
                

Christopher Stevens, M.D.

   2018   380,000   —     —     595,885   —     329,333   1,305,218

Former Chief Medical Officer

   2017   380,000   159,600   —     117,937   —     —     657,537

Treasurer; and
Derek Meisner, J.D., General Counsel

SUMMARY COMPENSATION TABLE
Name and Principal Position Year Salary ($) 
Bonus (1)
($) 
 
Stock
Awards
($) (2) (3)
Option
Awards
($) (2)
 
Non-Equity
Incentive Plan
Compensation
($) (4)
All Other
Compensation
($)
 Total ($) 
Paula Ragan, Ph.D.
President, Chief Executive Officer, Corporate Secretary and Director
 2020 543,400  —  1,690,827  —  271,700  8,169 (6)2,514,096  
 2019 492,276  —  824,938  893,460  286,000  1,177  2,497,851  
Adam S. Mostafa
Chief Financial Officer and Treasurer
 2020 400,000  —  612,950  —  163,600  564 (6)1,177,114  
 2019 372,275 —  155,819  168,771  168,341  1,025  866,231  
Derek Meisner
General Counsel
 2020400,000 (5)67,500 471,500 — 162,400 11,964 (6)1,113,364  
(1)

The amounts reported in this table (i) for Dr. Ragan and Mr. Mostafa, represent amounts earned for service as an executive officer of X4, and (ii) for Mr. Gray, Dr. Mantus, Dr. Russo and Dr. Stevens, represent amounts earned for service as an executive officer of Arsanis.

(2)

Except where noted otherwise, the amounts reported in the “Bonus” column reflect discretionary annual cash bonuses paida “Start Bonus” payable to Arsanis’s executive officers for their performance.

Mr. Meisner pursuant to his employment agreement totaling $135,000, half of which was payable in 2019 and half of which was payable in 2020.
(3)(2)

The amounts reported in the “Stock Awards” column and “Option Awards” column reflect the aggregate fair value of stock-based compensation awarded during the year computed in accordance with the provisions of Financial Accounting Standards Board, Accounting Standards Codification Topic 718, or ASC 718. For Dr. Ragan and Mr. Mostafa, see Note 11 to the X4 consolidated financial statements in our Amendment No. 1 to Current Report on Form8-K/A filed with the SEC on April 3, 2019, and for Mr. Gray, Dr. Mantus, Dr. Russo and

Dr. Stevens, seeSee Note 12 to the Arsanis consolidated financial statements in Arsanis’sX4 Pharmaceuticals Inc. Annual Report on Form10-K for the year ended December 31, 20182020 filed with the SEC on March 11, 2019,19, 2021, regarding assumptions underlying the valuation of equity awards.
(3)The amounts reported in the “Stock Awards” column reflect the grant date fair value for performance-based restricted stock units (“PRSUs”) granted to Dr. Ragan, Mr. Mostafa, and Mr. Meisner in fiscal 2020, which are reported based upon the probable outcome of the performance conditions on the grant date. The value of the PRSUs granted in fiscal 2020, assuming achievement of the maximum performance level, would have been: Dr. Ragan: $1,690,827, Mr. Mostafa: $612,950, and Mr. Meisner: $471,500.
(4)

For 2018,2020, represents amounts earned for the12-month period from January 1, 20182020 to December 31, 20182020 and paid in 2019,2021, and excludes payments made in 20182020 that were earned in 2017.2019. For 2017,2019, represents amounts earned for the12-month period from January 1, 20172019 to December 31, 20172019 and paid in 2018,2020, and excludes payments made in 20172020 that were earned in 2016.

2019.
(5)

The amounts reported inMr. Meisner’s employment with X4 began on November 4, 2019. Accordingly, his salary for 2019 reflects the “All Other Compensation” column reflect for 2018, $450 for Dr. Ragan and $90 for Mr. Mostafa, and for 2017, $576 for Dr. Ragan,amount he earned from November 4, 2019 through the end of the calendar year.

(6)Reflects $564 in life insurance premiums X4the Company paid for a term life insurance policy to benefit these executive officerseach of Dr. Ragan, Mr. Mostafa, and Mr. Meisner, respectively, with a face value of $300,000 and 401(k) matching contributions of $7,605 and $11,400 for 2018, severance paid to René Russo in connection with her separation as Arsanis’s PresidentDr. Ragan and CEO and retention bonus amounts accrued as of December 31, 2018 for David Mantus, Ph.D. and Christopher Stevens, M.D.

Mr. Meisner, respectively.
(6)

Mr. Mostafa’s employment with X4 began on September 5, 2018.

Outstanding Equity Awards at Fiscal Year End 2018


23


OUTSTANDING EQUITY AWARDS AT FISCAL YEAR-END
The following table sets forthshows for the fiscal year ended December 31, 2020, certain information regarding outstanding equity awards which consist of X4 stock options and X4 restricted stock, held by Dr. Ragan and Mr. Mostafa as of Decemberat fiscal year end for the Named Executive Officers.
OUTSTANDING EQUITY AWARDS AT DECEMBER 31, 2018. The share and per share amounts included in this table have not been adjusted to reflect the conversion of the shares in the Merger based on the exchange ratio of 0.5702 and do not reflect the Reverse Stock Split.

   Option Awards (1)   

Name

  Number of
Shares of X4

Common
Stock
Underlying
Unexercised
Options (#)
Exercisable
 Number of
Shares of X4

Common
Stock
Underlying
Unexercised
Options (#)
Unexercisable
 Option
Exercise
Price
($)
  Option
Expiration
Date

Paula Ragan, Ph.D.

    1,059,935 (2)   —  (2)   0.65    1/18/2026
    329,906 (3)   358,594 (3)   0.65    1/23/2027
    —  (4)   843,496 (4)   0.67    1/30/2028

Adam S. Mostafa

    —  (5)   659,067 (5)   0.99    10/3/2028

2020
   Option Awards Stock Awards
Name Grant Date 
Number of
Securities
Underlying
Unexercised
Options
(#)
Exercisable
 
Number of
Securities
Underlying
Unexercised
Options
(#)
Unexercisable
 
Option
Exercise
Price
($)
 Option
Expiration
Date
 Equity
incentive
plan awards:
number of
unearned
shares, units
or other
rights that
have not
vested
(#)
 Equity
incentive
plan awards:
market or
payout value
of unearned
shares, units
or other
rights that
have not
vested
($)
Performance-based restricted stock awards:
number of shares or units
of stock that
have not
vested
(#)
Performance-based restricted stock awards:
market or payout value of shares or units
of stock that
have not
vested
($)
Paula Ragan, Ph.D. 1/19/2016
(1) 
100,72906.84 1/18/2026 
 1/24/2017
(1) 
64,067
(2) 
1,363
(2) 
6.84 1/23/2027 
 1/31/2018
(1) 
60,120(3)20,040(3)7.08 1/30/2028 
 6/17/2019
(4) 
31,460
(5) 
52,433
(5) 
14.75 6/16/2029 
 6/17/2019
(4) 
41,946(6) 269,713
4/13/2020
(4) 
59,768(11)384,30889,652(12)576,462
Adam S. Mostafa 10/4/2018
(1) 
36,536(8)26,097(8)10.44 10/3/2028 
 6/17/2019
(4) 
5,943
(5) 
9,904(5) 14.75 6/16/2029 
 6/17/2019
(4) 
7,923(7) 50,945
4/13/2020
(4) 
21,666(11)139,31232,500(12)208,975
Derek Meisner11/26/2019(9) 16,042
(9) 
38,958(10)11.0311/25/2029
4/13/2020
(4) 
16,666(11)107,16225,000(12)160,750
(1)

Each of the outstanding equity awards in this tableThis award was granted pursuant to the X4 2015 Employee, Director and Consultant Equity Incentive Plan, as amended.

Plan.
(2)

Represents an option to purchase shares of X4 common stock granted on January 19, 2016. As of the date of grant, 33.33% of the shares underlying the option had vested and 2.0833% of the shares underlying the option vested, subject to continued service, on the 15th of each month thereafter until September 15, 2018.

(3)

Represents an option to purchase shares of X4 common stock granted on January 24, 2017. The shares underlying this option vest, subject to continued service, as follows: 25% of the shares vested on January 24, 2018 with the remainder vesting over the next three years in equal monthly installments on the grant day of each succeeding calendar month thereafter.

(4)

Represents an option to purchase shares of X4 common stock granted on January 1, 2018.

(3)The shares underlying this option vest, subject to continued service, as follows: 25% of the shares vested on January 1, 2019 with the remainder vesting over the next three years in equal monthly installments on the grant24th day of each succeeding calendar month thereafter.

(4)This award was granted pursuant to the 2017 Plan, as amended.
(5)

25% of the shares subject to the option shall vest on June 17, 2020, with the remainder vesting in equal installments of 2.0833% of the shares subject to the option on the last day of each month thereafter for a period of 36 months, subject to continued service through each such date.

(6)Represents an optionrestricted stock units, with each restricted stock unit representing the contingent right to purchase sharesreceive one share of X4 common stock granted on September 5, 2018. the applicable vesting date. No amount was paid upon grant of the restricted stock units. The restricted stock units vest, subject to continued service, in four equal annual installments on May 31, 2020, 2021, 2022 and 2023.
(7)Represents restricted stock units, with each restricted stock unit representing the contingent right to receive one share of common stock on the applicable vesting date. No amount was paid upon grant of the restricted stock units. The restricted stock units vest, subject to continued service, in four equal annual installments on June 30, 2020, 2021, 2022 and 2023.
(8)The shares underlying this option vest, subject to continued service, as follows: 25% of the shares vest on September 5, 2019, with the remainder vesting over the next three years in equal monthly installments on the grant5th day of each succeeding calendar month thereafter.

The following table sets forth information regarding outstanding equity awards, which consist of Arsanis stock options and Arsanis restricted stock, held by Mr. Gray, Dr. Mantus, Dr. Russo and Dr. Stevens as of December 31, 2018. The share and per share amounts included in this table do not reflect the Reverse Stock Split.

  Option Awards Restricted
Stock Awards
Name Number of
Shares of
Arsanis
Common
Stock
Underlying
Unexercised
Options  (#)
Exercisable
 Number of
Shares of
Arsanis
Common
Stock
Underlying
Unexercised
Options  (#)
Unexercisable
 Option
Exercise
Price ($)
 Option
Expiration
Date
 Number of Shares of
Restricted Arsanis
Common Stock

Michael P. Gray, M.B.A., C.P.A.

   —     —     —     —     250,000 (13)(14)
   35,258   16,016 (1)(14)  $9.39   7/20/2026   —  
   36,628   61,037 (2)(14)  $4.00   6/18/2027   —  
   —     110,000 (3)(14)  $17.34   3/7/2028   —  

David Mantus, Ph.D.

   11,599   3,050 (4)  $8.33   2/3/2026   —  
   7,327   4,392 (5)  $9.39   7/20/2026   —  
   16,481   27,468 (6)  $4.00   6/18/2027   —  
   —     50,000 (7)  $17.34   3/7/2028   —  

René Russo, Pharm.D., BCPS

   80,889   —  (8)  $8.20   7/21/2025   —  
   47,757   —  (8)  $9.39   7/20/2026   —  
   195,331   —  (8)  $4.00   6/18/2027   —  
   160,000   —  (8)  $17.34   3/7/2028   —  

Christopher Stevens, M.D.

   16,487   9,882 (9)(10)  $9.39   7/20/2026   —  
   16,482   27,466 (11)(10)  $4.00   6/18/2027   —  
   —     50,000 (12)(10)  $17.34   3/7/2028   —  

(1)

(9)This award was granted under the 2019 Plan.
(10)The shares underlying this option award vests over four years, withvest, subject to continued service, as follows: 25% of the shares underlyingsubject to the option vestedwere to vest on March 1, 2017 and 2.0833%November 4, 2020, with the remainder vesting in equal installments of 2.083% of the shares vesting monthlysubject to the option on the last day of each month thereafter for a period of 36 months.

24


(11)Represents performance-based restricted stock units for which the performance criteria has been achieved, as certified by the Compensation Committee of the Board on August 14, 2020 and August 17, 2020, and which vest in four equal installments, subject to continued service.

(2)

This option award vests over four years, with 25% of the shares underlying the option vestedservice, on June 19, 2018August 14, 2021, August 17, 2021, August 14, 2022 and 2.0833% of the shares vesting monthly thereafter, subject to continued service.

(3)

This option award vests over four years, with 25% of the shares underlying the option vested on March 7, 2019 and 2.0833% of the shares vesting monthly thereafter, subject to continued service.

(4)

This option award vests over four years, with 25% of the shares underlying the option vested on October 12, 2016 and 2.0833% of the shares vesting monthly thereafter, subject to continued service.

(5)

This option award vests over four years, with 25% of the shares underlying the option vested on June 1, 2017 and 2.0833% of the shares vesting monthly thereafter, subject to continued service.

(6)

This option award vests over four years, with 25% of the shares underlying the option vested on June 19, 2018 and 2.0833% of the shares vesting monthly thereafter, subject to continued service.

(7)

This option award vests over four years, with 25% of the shares underlying the option vested on March 7, 2019 and 2.0833% of the shares vesting monthly thereafter, subject to continued service.

(8)

In connection with Dr. Russo’s stepping down from her position as President and Chief Executive Officer of Arsanis, all unvested stock options held by Dr. Russo vested in full upon her letter agreement with the company, dated as of November 26, 2018, becoming effective and irrevocable as of December 3, 2018. See “Narrative Disclosure to Summary Compensation Table—Arsanis Compensation—Employment and Change in Control Arrangements—Letter Agreement for Dr. René Russo” below for more information.

(9)

This option award vests over four years, with 25% of the shares underlying the option vested on July 20, 2017 and 2.0833% of the shares vesting monthly thereafter, subject to continued service.

(10)

In connection with Dr. Stevens’s stepping down from his position as Chief Medical Officer of Arsanis, all unvested stock options held by Dr. Stevens vested in full upon his letter agreement with the company, dated

August 17, 2022.

as of January 15, 2019, and becoming effective and irrevocable as of January 22, 2019. See “Narrative Disclosure to Summary Compensation Table—Arsanis Compensation—Employment and Change in Control Arrangements—Letter Agreement for Dr. Christopher Stevens” below for more information.
(11)

This option award vests over four years, with 25% of the shares underlying the option vested on June 19, 2018 and 2.0833% of the shares vesting monthly thereafter, subject to continued service.

(12)

This option award vests over four years, with 25% of the shares underlying the option vested on March 7, 2019 and 2.0833% of the shares vesting monthly thereafter, subject to continued service.

(13)

ThisRepresents performance-based restricted stock award vests over four years, with 25% ofunits for which the shares underlying the option vesting on November 27, 2019 and 2.0833% of the shares vesting monthly thereafter, subject to continued service.

performance criteria has not been achieved.
(14)

In connection with Mr. Gray stepping down from his position as President and Chief Executive Officer of Arsanis, all unvested stock options and restricted stock held by Mr. Gray vested in full in connection with the closing of the Merger. See “Narrative Disclosure to Summary Compensation Table—Arsanis Compensation—Employment and Change in Control Arrangements—2018 Amended and Restated Employment Agreement for Michael P. Gray” below for more information.

Narrative Disclosure to Summary Compensation Table

X4 Compensation


NARRATIVETO SUMMARY COMPENSATION TABLE
The material terms of the elements of X4’sour executive compensation program for 2018 are described below.

Base Salary

Each named executive officer’sNamed Executive Officer’s base salary is a fixed component of annual compensation for performing specific duties and functions, and has been established by our board of directorsBoard taking into account each individual’s role, responsibilities, skills, and experience.

In February 2020, the Compensation Committee increased Dr. Ragan’s base salary for 2020 to $543,400 and increased Mr. Mostafa’s base salary for 2020 to $400,000.


Bonus
Pursuant to his employment agreement, Mr. Meisner was eligible to receive a “Start Bonus” in connection with the commencement of his employment equal to $135,000, $67,500 of which was payable in 2019 and $67,500 of which was payable in March 2020. The payment of the bonus is subject to recoupment if Mr. Meisner’s service is terminated before the one-year anniversary of the payment date.

Non-Equity Incentive Plan Compensation

Our annual bonus program is intended to reward our named executive officersNamed Executive Officers for meeting objective or subjective individual and/or company-wide performance goals for a fiscal year. For 20182020 and 2017, X4’s named executive officers2019, our Named Executive Officers received incentive compensation based upon the X4 board of directors’Board or X4’s compensation committee’sCompensation Committee’s determination of their respective achievement of and performance with respect to corporate objectives.

Dr. Ragan’s, Mr. Mostafa’s, and Mr. Meisner’s bonus targets were 50%, 40% and 40%, respectively, of their respective base salaries.


The impact of the COVID-19 pandemic continues to be difficult to assess or predict and depends on numerous evolving factors that we may not be able to accurately predict or effectively respond to, including, without limitation: the duration and scope of the outbreak; actions taken by governments, businesses, and individuals in response to the outbreak; the effect on economic activity and actions taken in response. While COVID-19 did not have a significant impact on our results of operations for the 2020 fiscal year, the impact of the global pandemic on our business and financial outlook are currently unknown. Continued uncertainty associated with the pandemic could impact our future results. Despite the uncertainties associated with the pandemic, we did not change our performance metrics under our incentive programs in light of COVID-19.

In February 2021, the Compensation Committee completed an evaluation of our overall performance for 2020 and the Named Executive Officers’ respective contributions in achieving this performance. The Compensation Committee’s review was based on company performance against corporate objectives, including advancing research and clinical development of mavorixafor, expanding the pipeline of other assets, advancing CXCR4 molecules and other assets to further expand our pipeline, maintaining business sustainability, building organizational strength, and preparing the commercialization of medicines for commercial use. Following such review, the Compensation Committee determined that the corporate performance objective were achieved at 100%, and Dr. Ragan had earned 100% of her target bonus for 2020, equal to a bonus of $271,700; Mr. Mostafa had earned 102% of his target bonus for 2020, equal to a bonus of $163,600; and Mr. Meisner had earned 102% of his target bonus for 2020, equal to a bonus of $162,400.
Long-Term Equity Incentives

Our equity grant program is intended to align the interests of our named executive officersNamed Executive Officers with those of our stockholders and to motivate them to make important contributions to our performance.


In April 2020, the Compensation Committee granted PRSUs to our Named Executive Officers, see the section captioned “Outstanding Equity Awards at Fiscal Year-End.” The PRSUs are divided into four equal tranches, with each tranche having
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its own separate corporate-based performance goal and service-based vesting conditions. The initial service-based vesting condition for each tranche requires continued service through the date the applicable corporate-based performance goal is certified as achieved by our Compensation Committee, and the remaining service-based vesting conditions require continued services through the first and second anniversaries of the date the applicable corporate-based performance goal is achieved. As of December 31, 2020, two of the four corporate-based performance goals have been achieved. In addition, 100% of the unvested portion of the PRSUs will vest upon the termination of the NEO’s employment by the Company without “cause” (as defined in the 2017 Plan) upon or at any time within 12 months following a “change of control” (as defined in the 2017 Plan), subject to the terms of each individual’s respective employment agreement.

Employment and Change in Control Arrangements

Paula Ragan, Ph.D.

On June 23, 2015, X4 entered into an executive employment agreement with Paula Ragan, Ph.D. Pursuant to the executive employment agreement, Dr. Ragan’s compensation consisted of base salary, annual bonus as determined by the X4 board of directors, equity grants as determined by the X4 board of directors, fringe benefits, vacation and reimbursement of ordinary and reasonableout-of-pocket expenses. In March 2017, Dr. Ragan’s base salary was increased from $350,000 to $364,000, and in March 2018, Dr. Ragan’s base salary was increased to $380,000. Dr. Ragan had an annual target bonus for 2017 and 2018 set at 35% of base salary.

On March 13, 2019, in connection with the closing of the Merger, we entered into an amended and restated executive employment agreement with PaulaDr. Ragan, Ph.D., pursuant to which Dr. Ragan agreed to continue

serving as our Chief Executive Officer. Pursuant to the agreement, Dr. Ragan’s compensation consists of base salary at an annual rate approved by the board of directorsour Board or an appropriate committee thereof, an annuala bonus as determined by our Board (provided that the board of directors, buttarget for such bonus shall be not less than 25% of Dr. Ragan’s annual base salary,salary), fringe benefits, vacation, reimbursement of ordinary and reasonableout-of-pocket expenses and coverage under our Directors’ and Officers’, or D&O, insurance policies, subject to the terms and conditions of such policies. Dr. Ragan’s 2020 base salary is currently equal to $520,000,was $543,000, with an annual target bonus set at 50% of her annual base salary, subject to review and adjustment each year by the board of directors.

Ifdirectors and in February 2021, Dr. Ragan’s 2021 base salary was set at $562,420.

Pursuant to her amended and restated executive employment agreement, as amended in February 2020, if Dr. Ragan’s employment is terminated for any reason, Dr. Ragan will be entitled to receive her 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. Ragan’s employment is terminated by us without cause or if Dr. Ragan resigns for good reason, each term as defined in the agreement, Dr. Ragan will be entitled to the following: (a) a continuation of base salary for 12 months, (b) apro-rata pro-rated portion of Dr. Ragan’sher at-target annual bonus for the calendar year in which the termination occurs, based on the period worked by Dr. Ragan during such calendar year prior to termination, (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 the normal share of costs 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 will become vested in the additional number of outstanding time-based equity awards granted to Dr. Ragan by us that would have otherwise vested had Dr. Ragan remained employed for an additional 12 months after her termination date. In addition, if Dr. Ragan’s employment is terminated without cause or if Dr. Ragan resigns for good reason within theone-year period following a change of control, as that term is defined in the agreement, Dr. Ragan will be entitled to the following: (a) a continuation of base salary for 18 months, (b) her full annual bonus for the calendar year in which the termination occurs, (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 the normal share of costs 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) automatic vesting in all outstanding time-based equity awards granted to Dr. Ragan by us, subject to the terms and conditions of the agreement. As a condition to receiving the foregoing severance benefits, Dr. Ragan 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.

In connection with the execution of her amended and restated employment agreement, Dr. Ragan also agreed to continue to abide by the terms of hernon-competition,non-solicitation,non-disclosure and intellectual property agreement.

Adam S. Mostafa

On July 23, 2018, X4 entered into an executive employment agreement with Adam S. Mostafa, pursuant to which Mr. Mostafa agreed to serve as X4’s Chief Financial Officer effective as of September 5, 2018. Pursuant to the executive employment agreement, Mr. Mostafa’s compensation consisted of base salary, potential annual bonus as determined by the X4 board of directors, a potential equity grant subject to approval by the X4 board of directors, fringe benefits, vacation and reimbursement of ordinary and reasonableout-of-pocket expenses. Mr. Mostafa’s initial base salary, which is subject to review and adjustment, was $340,000. The agreement provided for X4 to pay annual bonuses at X4’s sole discretion, as determined by the X4 board of directors, with an annual target bonus set at 35% of base salary. X4 also agreed to grant Mr. Mostafa an option to purchase 659,067 shares of X4 common stock (which share amount has not been adjusted to reflect the conversion of the shares in the Merger based on the exchange ratio of 0.5702 and does not reflect the Reverse Stock Split), subject to approval by the X4 board of directors and subject to certain vesting conditions, which option was granted on October 19, 2018.

On March 13, 2019, in connection with the closing of the Merger, we entered into an amended and restated executive employment agreement with Adam S.Mr. Mostafa, pursuant to which Mr. Mostafa agreed to continue serving as our Chief Financial Officer. Pursuant to the agreement, Mr. Mostafa’s compensation consists of base salary at an annual rate approved by the board of directorsour Board or an appropriate committee thereof, an annual bonus as determined by our Board (provided that the board of directors buttarget for such bonus shall not be less than 25% of Mr. Mostafa’s annual base salary,salary), fringe benefits, vacation, reimbursement of ordinary and reasonableout-of-pocket expenses and coverage under our D&O insurance policies, subject to the terms and conditions of such policies. Mr. Mostafa’s base salary is currently equal to $380,000,in 2020 was $400,000, with an annual target bonus set at 40% of his annual base salary, subject to review and adjustment each year by the board of directors.

Board and in February 2021, Mr. Mostafa’s 2021 base salary was set at $420,000.

If

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Pursuant to his amended and restated executive employment agreement, as amended in February 2020, if Mr. Mostafa’s employment is terminated for any reason, Mr. Mostafa 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. Mostafa’s employment is terminated by us without cause or if Mr. Mostafa resigns for good reason, each term as defined in the agreement, Mr. Mostafa will be entitled to the following: (a) a continuation of base salary for six months, (b) apro-rata pro-rated portion of Mr. Mostafa’sat-target annual bonus for the calendar year in which the termination occurs based on the period worked by Mr. Mostafa during such calendar year prior to termination, (c) so long as Mr. Mostafa 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 the normal share of costs we pay for current employees under such plan until the earlier of six months from the date of Mr. Mostafa’s termination or the date Mr. Mostafa is eligible to receive health benefits through another employer, and (d) Mr. Mostafa will become vested in the additional number of outstanding time-based equity awards granted to Mr. Mostafa by us that would have otherwise vested had Mr. Mostafa remained employed for an additional six months after his termination date. In addition, if Mr. Mostafa’s employment is terminated without cause or if Mr. Mostafa resigns for good reason within theone-year period following a change of control, as that term is defined in the agreement, Mr. Mostafa will be entitled to the following: (a) a continuation of base salary for 12 months, (b) Mr. Mostafa’s full annual bonus for the calendar year in which the termination occurs, (c) so long as Mr. Mostafa 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 the normal share of costs we pay for current employees under such plan until the earlier of six months from the date of Mr. Mostafa’s termination or the date Mr. Mostafa is eligible to receive health benefits through another employer, and (d) automatic vesting in all outstanding time-based equity awards granted to Mr. Mostafa by us, subject to the terms and conditions of the agreement. As a condition to receiving the foregoing severance benefits, Mr. Mostafa 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.
In connection with the execution of his amended and restated employment agreement, Mr. Mostafa agreed to continue to abide by the terms of hisnon-competition,non-solicitation,non-disclosure and intellectual property agreement.

E. Lynne Kelley, M.D.

On April 22, 2019, we entered into an

Derek Meisner

Pursuant to his amended and restated executive employment agreement, with E. Lynne Kelley, M.D., pursuant to which Dr. Kelley agreed to serve as our Chief Medical Officer commencing on April 24, 2019. Pursuant to the executive employment agreement, Dr. Kelley’s compensation consists ofamended in February 2020, Mr. Meisner’s annual base salary potentialfor 2020 was $400,000, and he is eligible for an annual bonus as determined by the board of directors, a potential equity grant subject to approval by the board of directors, fringe benefits, vacation and reimbursement of ordinary and reasonableout-of-pocket expenses. Dr. Kelley’s initial base salary, which is subject to review and adjustment, is $410,000. The agreement provides for theincentive payment of annual bonuses of upequal to 40% of his base salary. In February 2021, Mr. Meisner’s 2021 base salary as determinedwas set at our sole discretion. We also agreed to grant Dr. Kelley an option to purchase 37,170 shares of common stock, subject to approval by the board of directors and subject to certain vesting conditions, which option was granted on April 24, 2019.

$418,000.


If Dr. Kelley’sMr. Meisner’s employment is terminated for any reason, Dr. KelleyMr. Meisner is entitled to receive herhis 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. Kelley’sMr. Meisner’s employment is terminated by us without cause or if Dr. KelleyMr. Meisner resigns for good reason, each term as defined in the agreement, Dr. KelleyMr. Meisner will be entitled to the following: (a) a continuation of base salary for six months, (b) apro-rata pro-rated portion of Dr. Kelley’sMr. Meisner’s at-target annual bonus for the calendar year in which the termination occurs based on the period worked by Dr. KelleyMr. Meisner during such calendar year prior to termination, (c) so long as Dr. KelleyMr. Meisner is eligible for coverage under our health insurance plan, elects coverage, was covered prior to termination, and elects to exercise herhis rights under COBRA to continue participation in such plan, we will pay the normal share of costs we pay for current employees under such plan until the earlier of six months from the date of Dr. Kelley’sMr. Meisner’s termination or the date Dr. KelleyMr. Meisner is eligible to receive health benefits through another employer, and (d) Dr. KelleyMr. Meisner will become vested in the additional number of outstanding time-based equity awards granted to Dr. KelleyMr. Meisner by us that would have otherwise vested had Dr. KelleyMr. Meisner remained employed for an additional six months after herhis termination date. In addition, if Dr. Kelley’sMr. Meisner’s employment is terminated without cause or if Dr. KelleyMr. Meisner resigns for good reason within theone-year period following a change of control, as that term is defined in the agreement, Dr. KelleyMr. Meisner will be entitled to the following: (a) a continuation of base salary for 12 months, (b) Mr. Meisner’s full annual bonus for the calendar year in which the termination occurs, (c) so long as Mr. Meisner 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 the normal share of costs we pay for current employees under such plan until the earlier of six months from the date of Mr. Meisner’s termination or the date Mr. Meisner is eligible to receive health benefits through another employer, and (d) automatic vesting in all outstanding time-based equity awards granted to Dr. KelleyMr. Meisner by us, subject to the terms and conditions of the agreement. Dr. Kelley also entered intoAs anon-competition,non-solicitation,non-disclosure condition to receiving the foregoing severance benefits, Mr. Meisner must execute and intellectual propertynot revoke a separation agreement with us.

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.

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See the section captioned “Long-Term Equity Incentives” for vesting acceleration applicable to PRSUs held by our Named Executive Officers.

401(k) Plan

We maintain a defined contribution retirement plan that provides eligible U.S. employees with an opportunity to save for retirement on atax-advantaged basis. Eligible employees may defer eligible compensation on apre-tax basis, up to the statutorily prescribed annual limits on contributions under the Internal Revenue Code of 1986, as amended, or 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. 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 atax-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.

Health and Welfare Benefits

All of our full-time employees and certain of our part-time employees are eligible to participate in our employeehealth and welfare benefit plans, including our medical, dental, life and long-term disability insurance plans, in each case on the same basis as all of our other employees.

Arsanis Compensation

The material terms of the elements of Arsanis’s executive compensation program for 2018 are described below. The shareplans. Our health and per share amounts included in this sectionwelfare benefit plans do not reflect the Reverse Stock Split.

Arsanis’s compensation committee set base salaries and bonuses and grants equity incentive awards to its executive officers. In setting base salaries and bonuses and granting equity incentive awards, Arsanis’s compensation committee considered compensation for comparable positionsdiscriminate in the market, the historical compensation levels of its executives, individual and corporate performance as compared to its expectations and objectives, its desire to motivate its employees to achieve short- and long-term results that are in the best interests of its stockholders, and a long-term commitment to the company. As part of this process, Mr. Gray, as Arsanis’s president and chief executive officer, prepared performance evaluations for the other executive officers and recommended annual salary increases, annual stock option awards and cash bonuses to the compensation committee. The compensation committee conducted a performance evaluation of Mr. Gray. The compensation committee consulted with the board of directors as to the achievement of corporate objectives that drive contingent compensation awards.

The compensation committee has the authority to retain compensation consultants and other outside advisors to assist in the evaluation of executive officer compensation.

Base Salary

For 2017, the annualized base salary of each of Arsanis’s named executive officers was initially $350,000 for Mr. Gray, $310,000 for Dr. Mantus, $380,000 for Dr. Russo and $380,000 for Dr. Stevens. In September and October 2017, the board of directors and the compensation committee of the board of directors approved increases in the annualized base salaries of Dr. Russo, Mr. Gray and Mr. Mantus to $450,000, $400,000 and $340,000, respectively, in each case subject to and effective upon the closing of Arsanis’s initial public offering and, in the case of Mr. Gray’s increase, to be retroactive to September 27, 2017, which was the effective date of Mr. Gray’s promotion to the role of Chief Operating Officer and Chief Financial Officer. Mr. Gray previously served as Arsanis’s Chief Financial Officer and Chief Business Officer. In June 2018, Arsanis’s compensation committee approved an increase to the annualized base salary of Dr. Mantus to $370,000. In November 2018, Arsanis’s compensation committee approved an increase in the annualized base salary of Mr. Gray to $450,000 effective as of November 27, 2018, which was the effective date of Mr. Gray’s promotion to the role of President and Chief Executive Officer.

Arsanis used base salaries to recognize the experience, skills, knowledge and responsibilities required of all its employees, including its named executive officers. None of the Arsanis named executive officers is currently party to an employment agreementscope, terms or other agreement or arrangement that provides for automatic or scheduled increases in base salary.

Annual Bonus

The board of directors, in its discretion, awarded bonuses to the named executive officers from time to time. Arsanis typically established annual bonus targets based around a set of specified corporate goals for its named executive officers and conducted an annual performance review to determine the attainment of such goals. Arsanis’s management would propose bonus awards to the board of directors primarily based on such review process. Arsanis’s board of directors would make the final determination of the eligibility requirements for and the amount of such bonus awards.

Equity Incentives

Although Arsanis did not have a formal policy with respect to the grant of equity incentive awards to its executive officers, or any formal equity ownership guidelines applicable to them, Arsanis believed that equity grants provided its executives with a strong link to its long-term performance, create an ownership culture and helped to align the interests of its executives and its stockholders. In addition, Arsanis believed that equity grants with a time-based vesting feature promoted executive retention because this feature would incent its executive officers to remain in its employment during the vesting period. Accordingly, Arsanis’s board of directors would periodically review the equity incentive compensation of its named executive officers and from time to time would grant equity incentive awards to them in the form of stock options. In 2017, based upon Arsanis’s overall performance, Arsanis granted to Mr. Gray an option to purchase 97,665 shares of its common stock, to Dr. Mantus an option to purchase 43,949 shares of its common stock, to Dr. Russo an option to purchase 195,331 shares of its common stock, and to Dr. Stevens an option to purchase 43,948 shares of its common stock. In 2018, based upon its overall performance, Arsanis granted to Mr. Gray an option to purchase 110,000 shares of its common stock, to Dr. Mantus an option to purchase 50,000 shares of its common stock, to Dr. Russo an option to purchase 160,000 shares of its common stock, and to Dr. Stevens an option to purchase 50,000 shares of its common stock. These share amounts do not reflect the Reverse Stock Split.

Arsanis would use stock options to compensate its executive officers in the form of initial grants in connection with the commencement of employment and also at various times, often but not necessarily annually, if Arsanis performed as expected or better than expected. Prior to Arsanis’s initial public offering, the award of stock options to its executive officers was made by its board of directors or compensation committee. None of Arsanis’s executive officers is currently party to an employment agreement that provides for automatic award of stock options. Arsanis granted stock options to its executive officers with time-based vesting. The options that Arsanis granted to its executive officers typically become exercisable as to 25% of the shares underlying the option on the first anniversary of the grant date, and as to an additional 1/48th of the original number of shares underlying the option monthly thereafter. Vesting rights cease upon termination of employment and exercise rights cease shortly after termination, except that vesting is fully accelerated upon certain terminations in connection with a change of control (including the Merger) and exercisability is extended in the case of death or disability. Prior to the exercise of an option, the holder has no rights as a stockholder with respect to the shares subject to such option, including no voting rights and no right to receive dividends or dividend equivalents.

Prior to Arsanis’s initial public offering, Arsanis historically granted stock options with exercise prices that are equal to the fair market value of its common stock on the date of grant as determined by its board of directors or compensation committee, based on a number of objective and subjective factors. The exercise price of all stock options granted after the closing of Arsanis’s initial public offering is equal to the fair market value of shares of its common stock on the date of grant, which is determined by reference to the closing market price of its common stock on the date of grant.

In addition, in connection with his promotion to the role of President and Chief Executive Officer in November 2018, Arsanis granted to Mr. Gray a restricted stock award with respect to 250,000 shares of its common stock, which share number does not reflect the Reverse Stock Split. The restricted stock award would vest as to 25% of the shares subject to the award on theone-year anniversary of the date of grant, with the remainder vesting in equal monthly installments until the fourth anniversary of the date of grant, subject to Mr. Gray’s continued service with the company. The restricted stock award vested in full upon the closing of the Merger.

Employment and Change in Control Arrangements

Arsanis entered into written offer letters with each of its named executive officers. These agreements set forth the terms of the named executive officer’s compensation, including his or her initial base salary, severance and annual cash bonus opportunity. In addition, the agreements provide that the named executive officers are eligible to participate in company-sponsored benefit programs that are available generally to all of our employees.

Arsanis also entered into written bonus retention agreements and/or letter agreements with certain of its named executive officers which replaced such named executive officers’ prior severance benefits as set forth in their written offer letters, as described below.

2018 Amended and Restated Employment Agreement for Michael P. Gray

In connection with the appointment of Michael P. Gray as President and Chief Executive Officer of Arsanis, on November 26, 2018, Arsanis entered into an amended and restated employment agreement with Mr. Gray, which agreement became effective as of November 27, 2018 and replaced his October 10, 2017 amended and restated letter agreement. We refer to such amended and restated employment agreement as the Gray 2018 agreement. Under the Gray 2018 agreement, Mr. Gray’s base salary was $450,000 per annum and he was entitled to participate in Arsanis’s medical and other benefits programs, and was entitled to receive an annual bonus based on his individual performance and the company’s performance during the applicable year, all as determined by Arsanis’s board of directors in its sole discretion, at a target bonus rate of 55% of his annualized base salary.

The Gray 2018 agreement provides that the vesting of all equity awards granted to Mr. Gray before the closing of Arsanis’s initial public offering on November 20, 2017 would accelerate in full upon a “change of control” of the company (as defined in the Gray 2018 agreement and including the Merger). Specifically, on July 20, 2016, Mr. Gray received a grant of options to purchase 51,274 shares of common stock with an exercise price of $9.39 per share, which vested in full upon the closing of the Merger. On June 19, 2017, Mr. Gray received a grant of options to purchase 97,665 shares of common stock with an exercise price of $4.00 per share, which vested in full upon the closing of the Merger. The Gray 2018 agreement also provides that, subject to approval of Arsanis’s board of directors, Arsanis would grant Mr. Gray a restricted stock award with respect to 250,000 shares of common stock, which grant Arsanis’s board of directors did approve, became effective on November 27, 2018 and vested in full upon the closing of the Merger. Pursuant to the terms of the Gray 2018 agreement, Mr. Gray’s employment with the company could be terminated at any time, with or without “cause” (as defined in the Gray 2018 agreement and set forth below) by either Mr. Gray or Arsanis. If Arsanis terminated Mr. Gray’s employment without cause or Mr. Gray terminated his employment for “good reason” (as defined in the Gray 2018 agreement and set forth below) he would be entitled to (i) 12 months’ pay at his then-current base salary, (ii) a portion of the same year’s target bonus,pro-rated to reflect the portion of the year elapsed, and (iii) COBRA premium benefits for up to 12 months. If Arsanis terminated Mr. Gray’s employment without cause or Mr. Gray terminated his employment for good reason within 18 months following a change of control of the company, Mr. Gray would be entitled to (i) an amount equal to the sum of (x) 1.5 times his then-current base salary and (y) 1.5 times his target bonus for the year of termination, and (ii) COBRA premium benefits for up to 12 months. In addition, on March 7, 2018, Mr. Gray received a grant of options to purchase 110,000 shares of

common stock with an exercise price of $17.34 per share. If Arsanis terminated Mr. Gray’s employment without cause or Mr. Gray terminated his employment for good reason, each within 18 months following a change of control (including the Merger), this option would vest in full, and the period during which Mr. Gray would be entitled to exercise certain stock options granted to him in June 2017 would be extended for up to two years following his separation date. As a result of his resignation in connection with the Merger, we paid Mr. Gray severance benefits in March 2019 and his outstanding options and restricted stock vested in full. The Gray 2018 agreement also provides for a limitation on payments under the Gray 2018 agreement if limiting the payments would leave Mr. Gray in a better net position than bearing the tax penalties under Section 280G of the Code.

Pursuant to the Gray 2018 agreement:

The following, as determined by Arsanis’s board of directors in its reasonable judgment, constitutes “cause” for termination: (i) the commission of, or indictment or conviction for, any felony, or any other crime involving dishonesty; (ii) participation in any fraud, deliberate and substantial misconduct, breach of duty of loyalty or breach of fiduciary duty against the company; (iii) intentional and substantial damage to any property of the company; (iv) failure of performance of Mr. Gray’s duties under the Gray 2018 agreement (not attributable to sickness, disability or death) after reasonable written notice no later than 30 days following the occurrence of the failure and a30-day opportunity to cure, provided, however, that such opportunity to cure shall only apply to any failure that the board of directors, in its reasonable discretion, deems susceptible to cure; or (v) Mr. Gray’s breach of any material provision of the Gray 2018 agreement, his Invention,Non-Competition,Non-Solicitation andNon-Disclosure Agreement, or any other agreement to which he and the company are both parties, after reasonable written notice no later than 30 days following the occurrence of the breach and a30-day opportunity to cure, provided, however, that such opportunity to cure shall only apply to any breach that the board of directors, in its reasonable discretion, deems susceptible to cure, and that any breach by Mr. Gray of his obligations of confidentiality ornon-competition under hisnon-disclosure agreement shall be deemed not susceptible to cure.

The following, if occurring without Mr. Gray’s consent, constitutes “good reason” for termination: (i) a material and adverse diminution of Mr. Gray’s duties and responsibilities with the company, provided that such change is not in connection with a termination of his employment relationship with the company; (ii) a material diminution of Mr. Gray’s then base salary, provided that such change is not in connection with a termination of his employment relationship with the company; (iii) relocation of Mr. Gray’s principal place of employment outside a 30 mile radius from Boston, Massachusetts, if such relocation increases his daily commuting distance; or (iv) a material breach by the company of the Gray 2018 agreement.

“Change of control” means the first to occur of any of the following: (i) a merger or consolidation, business combination, acquisition or similar transaction (a “Transaction”) in which (A) the company is a constituent party, or (B) a subsidiary of the company is a constituent party and the company issues shares of its capital stock pursuant to such Transaction, except in the case of either clause (A) or (B) any such Transaction involving the company or a subsidiary of the company in which the beneficial owners of the shares of our capital stock outstanding immediately prior to such Transaction continue beneficially to own, immediately following such Transaction, at least a majority by voting power of our capital stock of (x) the surviving or resulting corporation or (y) if the surviving or resulting corporation is a wholly owned subsidiary of another corporation immediately following such Transaction, the parent corporation of such surviving or resulting corporation; (ii) the sale, lease, transfer, exclusive license or other disposition, in a single transaction or series of related transactions, by the company or a subsidiary of the company of all or substantially all the assets of the company and the company’s subsidiaries taken as a whole (except in connection with a Transaction not constituting a change of control under clause (i) or where such sale, lease, transfer, exclusive license or other disposition is to a wholly owned subsidiary of the company); or (iii) the sale or transfer, in a single transaction or series of related transactions, by our stockholders of more than 50% by voting power of our then-outstanding capital stock to any person or entity or group of affiliated persons or entities.

Amended and Restated Letter Agreement and Retention Bonus Agreement for Dr. David Mantus

On November 26, 2018, Arsanis entered into a retention bonus agreement with Dr. David Mantus, Arsanis’s Chief Development Officer, which replaced Dr. Mantus’s existing severance benefits as set forth in the amended and restated letter agreement, dated October 10, 2017, between Dr. Mantus and us. Dr. Mantus was eligible to receive payment from the company for benefits continuation and any equity acceleration provided by his amended and restated letter agreement. Under his retention bonus agreement, Dr. Mantus was eligible for a retention bonus payment of $481,000 upon the earliest to occur of the following, subject to Dr. Mantus’s continued service with the company on such date: (i) March 31, 2019, (ii) the closing of a “change of control” of the company (as defined in the retention bonus agreement and including the Merger), (iii) the termination of Dr. Mantus’s employment by the company without “cause” (as defined in the retention bonus agreement and set forth below), or (iv) Dr. Mantus’s death. Dr. Mantus’s receipt of the retention bonus payment was conditioned upon his entering into a release of claims agreementoperation in favor of the company. Dr. Mantus’s retention bonus was paid in March 2019.

Except as expressly modified by the retention bonus agreement, Dr. Mantus’s amended and restated letter agreement remains in full force and effect. Dr. Mantus’s amended and restated letter agreement provides that the vesting of all equity awards granted to Dr. Mantus before the closing of Arsanis’s initial public offering on November 20, 2017 would accelerate in full upon a “change of control” of the company (as defined in the amended and restated employment agreement), which equity awards vested in full as a result of the Merger. The amended and restated letter agreement also provides Dr. Mantus’s employment with us may be terminated at any time, with or without “cause” (as defined in the amended and restated letter agreement and set forth below) by either Dr. Mantus or us. If we terminate Dr. Mantus’s employment without cause or Dr. Mantus terminates his employment for “good reason” (as defined in the amended and restated letter agreement and set forth below), he will be entitled to COBRA premium benefits for up to 12 months. If we terminate Dr. Mantus’s employment without cause or Dr. Mantus terminates his employment for good reason within 12 months following a change of control of the company, Dr. Mantus will be entitled to (i) COBRA premium benefits for up to 12 months; and (ii) vesting in full of all unvested stock options and other equity awards then held by him. The amended and restated letter agreement also provides for a limitation on payments under the agreement if limiting the payments would leave Dr. Mantus in a better net position than bearing the tax penalties under Section 280G of the Code.

On February 26, 2016, Dr. Mantus received a grant of options to purchase 14,649 shares of our common stock with an exercise price of $8.33 per share. On July 20, 2016, Dr. Mantus received a grant of options to purchase 11,719 shares of our common stock with an exercise price of $9.39 per share. On June 19, 2017, Dr. Mantus received a grant of options to purchase 43,949 shares of our common stock with an exercise price of $4.00 per share. Each of these option grants vested in full upon the closing of the Merger.

On March 7, 2018, Dr. Mantus received a grant of options to purchase 50,000 shares of our common stock with an exercise price of $17.34 per share. If we terminate Dr. Mantus’s employment without cause or Dr. Mantus terminates his employment for good reason, each within 12 months following a change of control, these options will vest in full.

Pursuant to Dr. Mantus’s amended and restated letter agreement and retention bonus agreement:

The following, as determined by the board of directors in its reasonable judgment, constitutes “cause” for termination: (i) the commission of, or indictment or conviction for, any felony, or any other crime involving dishonesty; (ii) participation in any fraud, deliberate and substantial misconduct, breach of duty of loyalty or breach of fiduciary duty against the company; (iii) intentional and substantial damage to any property of the company; (iv) failure of performance of Dr. Mantus’s duties (not attributable to sickness, disability or death) after reasonable written notice no later than 30 days following the occurrence of the failure and a30-day opportunity to cure, provided, however, that such opportunity to cure shall only apply to any failure that the our board of directors, in its reasonable discretion, deems susceptible to cure; or (v) Dr. Mantus’s breach of any material provision of his amended and restated letter agreement, his Invention,Non-Competition,

Non-Solicitation andNon-Disclosure Agreement, or any other agreement to which he and the company are both parties, after reasonable written notice no later than 30 days following the occurrence of the breach and a30-day opportunity to cure, provided, however, that such opportunity to cure shall only apply to any breach that the board of directors, in its reasonable discretion, deems susceptible to cure, and that any breach by Dr. Mantus of his obligations of confidentiality ornon-competition under hisnon-disclosure agreement shall be deemed not susceptible to cure.

“Change of control” means the first to occur of any of the following: (i) a merger or consolidation, business combination, acquisition or similar transaction (a “Transaction”) in which (A) the company is a constituent party, or (B) a subsidiary of the company is a constituent party and the company issues shares of capital stock pursuant to such Transaction, except in the case of either clause (A) or (B) any such Transaction involving the company or a subsidiary of the company in which the beneficial owners of the shares of the company’s capital stock outstanding immediately prior to such Transaction continue beneficially to own, immediately following such Transaction, at least a majority by voting power of the capital stock of (x) the surviving or resulting corporation or (y) if the surviving or resulting corporation is a wholly owned subsidiary of another corporation immediately following such Transaction, the parent corporation of such surviving or resulting corporation; (ii) the sale, lease, transfer, exclusive license or other disposition, in a single transaction or series of related transactions, by the company or a subsidiary of the company of all or substantially all the assets of the company and the company’s subsidiaries taken as a whole (except in connection with a Transaction not constituting a change of control under clause (i) or where such sale, lease, transfer, exclusive license or other disposition is to a wholly owned subsidiary of the company); or (iii) the sale or transfer, in a single transaction or series of related transactions, by the company’s stockholders of more than 50% by voting power of our then-outstanding capital stock to any person or entity or group of affiliated persons or entities.

Pursuant to Dr. Mantus’s amended and restated letter agreement:

The following, if occurring without Dr. Mantus’s consent, constitutes “good reason” for termination: (i) a material and adverse diminution of Dr. Mantus’s duties and responsibilities with the company, provided that such change is not in connection with a termination of his employment relationship with the company; (ii) a material diminution of Dr. Mantus’s then base salary, provided that such change is not in connection with a termination of his employment relationship with the company; (iii) relocation of Dr. Mantus’s principal place of employment outside a 30 mile radius from Boston, Massachusetts, if such relocation increases his daily commuting distance; or (iv) a material breach by the company of Dr. Mantus’s amended and restated letter agreement.

Letter Agreement for Dr. René Russo

In connection with Dr. Russo stepping down from her position as President and Chief Executive Officer of Arsanis, on November 26, 2018, Dr. Russo signed a letter agreement, which upon expiration of a release revocation period replaces Dr. Russo’s existing severance benefits as set forth in the amended and restated letter agreement, dated October 10, 2017, between Dr. Russo and Arsanis. Under the November 2018 letter agreement, in exchange for, among other things, her general release of claims in favor of the company, Dr. Russo is entitled to severance benefits comprised of (i) alump-sum payment of $1,046,250; (ii) COBRA premium benefits for up to 18 months; and (iii) the vesting in full of all unvested stock options then held by Dr. Russo. In addition, Arsanis agreed to extend the period during which Dr. Russo may exercise the stock options granted to her in June 2017 for up to two years following her separation date, and also agreed to waive Dr. Russo’s post-employmentnon-competition obligations.

On July 22, 2015, Dr. Russo received a grant of options to purchase 80,889 shares of common stock with an exercise price of $8.20 per share. On July 20, 2016, Dr. Russo received a grant of options to purchase 47,757 shares of common stock with an exercise price of $9.39 per share. On June 19, 2017, Dr. Russo received a grant of options to purchase 195,331 shares of common stock with an exercise price of $4.00 per share. As described above, Dr. Russo will have the right to exercise this June 2017 option for a period of up totwo-years following

her separation date. On March 7, 2018, Dr. Russo received a grant of options to purchase 160,000 shares of common stock with an exercise price of $17.34 per share. All unvested stock options held by Dr. Russo vested in full upon her letter agreement becoming effective and irrevocable.

Notwithstanding her stepping down as President and Chief Executive Officer of the company, Dr. Russo’s equity awards will remain outstanding in accordance with their terms (subject to the provisions of her letter agreement described above) for so long as she continues to serve as a director of the Company following the Merger.

Letter Agreement for Dr. Christopher Stevens

Effective January 15, 2019, Dr. Stevens stepped down from his position as Chief Medical Officer of Arsanis. In connection with the termination of his employment, Dr. Stevens signed a letter agreement, dated January 15, 2019, which upon expiration of a revocation period replaces Dr. Stevens’s existing severance benefits as set forth in the retention bonus agreement, dated November 26, 2018, between Dr. Stevens and Arsanis and the amended and restated letter agreement, dated October 10, 2017, between Dr. Stevens and Arsanis. Under the January 2019 letter agreement, in exchange for, among other things, his general release of claims in favor of the company, Dr. Stevens is entitled to severance benefits comprised of (i) alump-sum payment of $494,000; (ii) COBRA premium benefits for up to 12 months; and (iii) the vesting in full of all unvested stock options then held by Dr. Stevens, which will remain exercisable for the period of time set forth in the applicable grant agreement. In addition, we agreed to waive Dr. Stevens’s post-employmentnon-competition obligations.

On July 20, 2016, Dr. Stevens received a grant of options to purchase 26,369 shares of our common stock with an exercise price of $9.39 per share. On June 19, 2017, Dr. Stevens received a grant of options to purchase 43,948 shares of common stock with an exercise price of $4.00 per share. On March 7, 2018, Dr. Stevens received a grant of options to purchase 50,000 shares of common stock with an exercise price of $17.34 per share. All unvested stock options held by Dr. Stevens vested in full upon his letter agreement becoming effective and irrevocable as of January 22, 2019.

Other Agreements

Each of the Arsanis named executive officers entered into a standard form agreement with respect tonon-competition,non-solicitation, confidential information and assignment of inventions. Under this agreement, each Arsanis named executive officer agreed not to compete with us during his or her employment and for a period of one year after the termination of his or her employment, not to solicit our employees, consultants, clients or customers during his or her employment and for a period of one year after the termination of his or her employment, and to protect our confidential and proprietary information indefinitely. In addition, under this agreement, each named executive officer has agreed that we own all inventions that are developed by such executive officer during his or her employment with us that are within the field of monoclonal antibody-based therapeutic treatments for infectious diseases. Each named executive officer also agreed to provide us with anon-exclusive, royalty-free, perpetual license to use any prior inventions that such executive officer incorporates into inventions assigned to us under this agreement.

401(k) Retirement Plan

We maintain a defined contribution employee retirement plan for Arsanis’s employees, including the named executive officers. The plan is intended to qualify as a

tax-qualifiedDIRECTOR COMPENSATION 401(k) plan so that contributions to the 401(k) plan, and income earned on such contributions, are not taxable to participants until withdrawn or distributed from the 401(k) plan (except in the case of contributions under the 401(k) plan designated as Roth contributions). Under the 401(k) plan, each employee is fully vested in his or her deferred salary contributions. Employee contributions are held and invested by the plan’s trustee as directed by participants. The 401(k) plan

FOR FISCAL 2020

provides us with the discretion to match employee contributions, but to date we have not provided any employer matching contributions.

Tax Considerations

The compensation committee of our board of directors considers the potential future effects of Section 162(m) of the Code on compensation paid to our named executive officers. 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 and the three most highly compensated executive officers (other than the chief executive officer and chief financial officer). Pursuant to tax legislation signed into law on December 22, 2017 (the “Tax Act”), for taxable years beginning after December 31, 2017, the Section 162(m) deduction limitation is expanded so that it also applies to compensation in excess of $1 million paid to a public company’s chief financial officer. Historically, compensation that qualified under Section 162(m) as performance-based compensation was exempt from the deduction limitation. However, subject to certain transition rules, the Tax Act eliminated the qualified performance-based compensation exception. As a result, for taxable years beginning after December 31, 2017, all compensation in excess of $1 million paid to each of the executives described above (other than certain grandfathered compensation or compensation paid pursuant to certain equity awards granted before or during a transition period following Arsanis’s initial public offering) will not be deductible by us.

Director Compensation

Arsanis Director Compensation

Under Arsanis’s director compensation program, Arsanis paid its

Name (1)
Fees Earned
or Paid in
Cash
($)
 
Option
Awards
($)(2)(3)
Total
($)
William E. Aliski, MPA$41,912 $21,728  $63,640 
Gary J. Bridger, Ph.D.$44,838 $21,728 $66,566 
Alison Lawton (4)
$11,353 $37,516 $48,869 
David McGirr, M.B.A.$54,000 $21,728 $75,728 
René Russo., Pharm.D.$35,000 $21,728 $56,728 
Murray W. Stewart, M.D.$50,700 $21,728 $72,428 
Michael S. Wyzga$86,500 $21,728 $108,228 
non-employee
directors a cash retainer for service on the board of directors and for service on each committee on which the director is a member. The chairman of the board, the lead independent director and the chair of each committee received higher retainers for such service. These fees were payable in arrears in four equal quarterly installments on the last day of each quarter, provided that the amount of such payment would be prorated for any portion of such quarter that the director was not serving on the board of directors, on such committee or in such position. The fees paid tonon-employee directors for service on the board of directors, for service as a lead independent director and for service on each committee of the board of directors on which the director is a member were as follows. The share and per share amounts included in this section “Arsanis Director Compensation” do not reflect the Reverse Stock Split.

   Member
Annual Fee
  Chairman
Annual Fee
  Lead
Independent
Director
Annual Fee

Board of Directors

   $35,000   $75,000   $50,000

Audit Committee

   $7,500   $15,000    —  

Compensation Committee

   $5,000   $10,000    —  

Nominating and Corporate Governance Committee

   $4,000   $8,000    —  

Arsanis also reimbursed itsnon-employee directors for reasonable travel and other expenses incurred in connection with attending meetings of the board of directors and any committee of the board of directors on which they served.

In addition, under Arsanis’s director compensation program, Arsanis granted the directors who were in office at the time of the closing of Arsanis’s initial public offering, and would grant to newnon-employee directors upon their initial election to the board of directors, an option to purchase 25,000 shares of common stock. Each of these options would vest as to 33.3333% of the shares of common stock underlying such option on the first anniversary of the date of grant, with the remainder vesting in equal monthly installments until the third anniversary of the date of grant, subject to thenon-employee director’s continued service as a director. Further,

on the dates of each of Arsanis’s annual meetings of stockholders, eachnon-employee director that has served on the board of directors for at least six months will automatically receive, under our 2017 Equity Incentive Plan, or the 2017 Plan, an option to purchase 10,000 shares of common stock. Each of these options would vest in equal monthly installments until the first anniversary of the date of grant (or, if earlier, the date of our next annual meeting of stockholders following the date of grant) unless otherwise provided at the time of grant, subject to thenon-employee director’s continued service as a director, with full acceleration of vesting upon a change in control of the company. All options issued tonon-employee directors under the director compensation program were issued at exercise prices equal to the closing price of the common stock on the date of grant.

Mr. Gray, an Arsanis director who also served as President and Chief Executive Officer and Chief Financial Officer until the closing of the Merger, did not receive any additional compensation for his service as a director. Dr. Russo also served as President and Chief Executive Officer during 2018, until she stepped down from such positions on November 26, 2018. Dr. Russo did not receive any additional compensation for her service as a director. Mr. Gray and Dr. Russo are two of our named executive officers and, accordingly, the compensation that we pay to Mr. Gray and Dr. Russo is discussed under “—Summary Compensation Table” and “—Narrative Disclosure to Summary Compensation Table.”

The following table sets forth information regarding compensation earned by Arsanis’snon-employee directors during fiscal 2018.

Name  Fees Earned
or Paid
in Cash
($)
  Option Awards
($)(1)
  Total
($)

Tillman U. Gerngross, Ph.D.

    94,615    111,785    206,400

William Clark, M.B.A.

    47,871    111,785    159,656

Carl Gordon, Ph.D., C.F.A.

    47,871    111,785    159,656

David McGirr, M.B.A.

    56,319    111,785    168,104

Terrance McGuire

    48,434    111,785    160,219

Claudio Nessi, Ph.D., M.B.A.

    39,423    111,785    151,208

Michael Ross, Ph.D.

    45,055    111,785    156,840

Amy Schulman, J.D.

    72,088    111,785    183,873

(1)

Dr. Ragan, one of our directors who also serves as our Chief Executive Officer, President and Secretary, did not receive any additional compensation for her service director. Dr. Ragan is a Named Executive Officer and, accordingly, the compensation that we pay to Dr. Ragan is described under “—Summary Compensation Table” and “—Narrative Disclosure to Summary Compensation Table.”

(2)The amounts reported in the “Option Awards” column reflect the aggregate fair value of stock-based compensation awarded during the year computed in accordance with the provisions of ASC 718. See Note 12 to Arsanis’sour consolidated financial statements appearing in Arsanis’sour Annual Report on Form10-K for the year ended December 31, 20182020 filed with the SEC on March 11, 2019,19, 2021, regarding assumptions underlying the valuation of equity awards.

As of December 31, 2018, Arsanis’snon-employee directors held the following stock options, all of which were granted under our 2010 Special Stock Incentive Plan, as amended, or the 2010 Plan, our 2011 Stock Incentive Plan, or 2011 Plan, and our 2017 Plan:

Name(3)The aggregate number of shares subject to outstanding stock options held by each director listed in the table above as of December 31, 2020 was as follows: 10,281 shares for Mr. Aliski; 31,851 shares for Dr. Bridger; 6,854 for Ms. Lawton; 12,686 shares for Mr. McGirr; 33,520 shares for Dr. Russo; 10,281 shares for Dr. Stewart; and 80,605 shares for Mr. Wyzga.
Option Awards

Tillman U. Gerngross, Ph.D.

100,484

William Clark, M.B.A.

(4)
35,000

Carl Gordon, Ph.D., C.F.A.

35,000

David McGirr, M.B.A.

35,000

Terrance McGuire

35,000

Claudio Nessi, Ph.D., M.B.A.

35,000

Michael Ross, Ph.D.

35,000

Amy Schulman, J.D.

41,482

René Russo

483,977Ms. Lawton joined our Board in October 2020.

28


NARRATIVE TO DIRECTOR COMPENSATION TABLE
Non-Employee Director Compensation Policy Following the Merger

On March 13, 2019, we adopted a director compensation policy based on Arsanis’s existing director compensation program. Pursuant to the policy, the annualretainer for non-employee directors is $35,000 and the annual retainer for the chair of the board of directors is $75,000. Annual retainers for committee membership are as follows:

Audit committee chairperson

   $15,000

Audit committee member

   $7,500

Compensation committee chairperson

   $10,000

Compensation committee member

   $5,000

Nominating and corporate governance committee chairperson

   $8,000

Nominating and corporate governance committee member

   $4,000

These fees are payable in arrears in four equal quarterly installments on the last day of each quarter, provided that the amount of such payment will be prorated for any portion of such quarter that a director is not serving on the our board of directors, on such committee or in such position.Non-employee directors are also reimbursedfor reasonable out-of-pocket business expenses incurred in connection with attending meetings of the board of directors and any committee of the board of directors on which they serve and in connection with other business related to the board of directors. Directors may also be reimbursed for reasonable out-of-pocket business expenses authorized by the board of directors or a committee that are incurred in connection with attending conferences or meetings with management in accordance with a travel policy, as may be in effect from time to time.

In addition to the above fees, the board of directors may determine that additional committee fees are appropriate and should be payable for any newly created committee of the board of directors.

In addition, we grant

We have historically granted to new non-employee directors, upon their initial election to the board of directors, an option to purchase 6,854 shares of our common stock at an exercise price equal to the closing price of our common stock on the date of grant. In February 2021, our Board, upon the recommendation of the Compensation Committee, approved an increase in this initial option grant to 12,250 shares of common stock. Each of these options has a term of 10 years from the date of the award and vests as to 33.3333% of the shares of common stock underlying such option on the first anniversary of the date of grant, with the remainder vesting in equal monthly installments of 2.7777% of the shares of common stock underlying such optionuntil the 36-month anniversary of the date of grant, subject to the non-employee director’s continued service as a director. This vesting accelerates as to 100% of the shares upon a change in control of the Company.

Further, on the dates of each of our annual meetingsof stockholders, we have historically granted to each non-employee director that has served on our board of directors for at least six months automatically receives an option to purchase 3,427 shares of our common stock at an exercise price equal to the closing price of our common stock on the date of the grant. In February 2021, our Board, upon the recommendation of the Compensation Committee, approved an increase in this annual option grant. Starting with the Annual Meeting, on the dates of each of our annual meetings of stockholders, each non-employee director that that has served on our board of directors for at least six months will automatically receive an option to purchase 6,000 shares of our common stock at an exercise price equal to the closing price of our common stock on the date of the grant. Each of these options has a term of 10 years from the date of the award and vests in equal monthly installments of 8.333% of the shares of our common stock underlying such optionuntil the 12-month anniversary of the date of grant (or, if earlier, the date of our next annual meeting of stockholders following the date of grant) unless otherwise provided at the time of grant,subject to the non-employee director’s continued service as a director, with 100% acceleration of vesting upon a change in control of the Company.


We pay our non-employee directors a cash retainer for service on the Board of Directors and for service on each committee on which the director was a member. The Chairman of the Board, the Lead Independent Director and the Chair of each committee received higher retainers for such service. These fees are payable in arrears in four equal quarterly installments on the last day of each quarter, provided that the amount of such payment would be prorated for any portion of such quarter that the director was not serving on the Board of Directors, on such committee or in such position. The fees paid to non-employee directors for service on the Board of Directors, for service as a Lead Independent Director and for service on each committee of the Board of Directors on which the director was a member were as follows.
   Member
Annual Fee
   Chairman
Annual Fee
   Lead
Independent
Director
Annual Fee
 
Board of Directors  $35,000   $75,000   $50,000 
Audit Committee  $7,500   $15,000    —   
Compensation Committee  $5,000   $10,000    —   
Nominating and Corporate Governance Committee  $4,000   $8,000    —   
We also reimburse our non-employee directors for reasonable travel and other expenses incurred in connection with attending meetings of the Board of Directors and any committee of the Board of Directors on which they served.


29


SECURITIES AUTHORIZED FOR ISSUANCE UNDER EQUITY COMPENSATION PLAN INFORMATION

Plan Category

  Number of
securities
to be
issued upon
exercise  of
outstanding
options,
warrants
and rights
 Weighted
average
exercise
price of
outstanding
options,
warrants
and  rights
 Number of
securities
remaining
available for
future
issuance
under  equity
compensation
plans (excluding
securities
reflected in
column (a))
   (a) (b) (c)

Equity compensation plans approved by security holders

    1,953,804 (1)  $10.16 (2)   308,288 (3)

Equity compensation plans not approved by security holders

    —     —     —  

Total

    1,953,804  $10.16   308,288 (4)

PLANS

EQUITY COMPENSATION PLAN INFORMATION
The following table provides certain information with respect to all of our equity compensation plans in effect as of December 31, 2020:

Plan CategoryNumber of securities to
be issued upon exercise
of outstanding options,
warrants and rights
(a)
Weighted-average
exercise price of
outstanding
options, warrants
and rights
(b)
Number of securities
remaining available
for issuance under
equity compensation
plans (excluding
securities reflected
in column (a))
(c)
Equity compensation plans approved by security holders488,043 (1)$23.85 (2)254,796 (3)
Equity compensation plans not approved by security holders1,386,471 (4)$9.15 (5)162,156 (6)
Total1,874,514 $12.94 416,952 (7)

(1)

Consists of (i) 103,10086,573 shares to be issued upon exercise of outstanding options under our 2010 Special Stock Incentive Plan, as amended, or the 20102011 Plan, as of December 31, 2018,2020, and (ii) 967,404401,470 shares to be issued upon exercise of outstanding options under our 2011 Stock Incentive Plan, or 2011 Plan, as of December 31, 2018 and (iii) 883,300 shares to be issued upon exercise of outstanding options under ourthe 2017 Plan, as of December 31, 2018.

2020.
(2)

Consists of the weighted averageweighted-average exercise price of the 1,953,804488,043 stock options outstanding on December 31, 2018.

2020.
(3)

Consists of (i) 308,28825,732 shares that remained available for future issuance under ourthe 2017 Plan as of December 31, 2018,2020 and (ii) 219,111229,064 shares that remained available for future issuance under our 2017 Employee Stock Purchase Plan or 2017 ESPP,(the “2017 ESPP”), as of December 31, 2018.2020. No shares remained available for future issuance under the 2010 Plan or the 2011 Plan, as of December 31, 2018.

2020.
(4)

OurConsists of (i) 743,421 shares to be issued upon exercise of outstanding options under the 2015 Plan, as of December 31, 2020 and (ii) 643,050 shares to be issued upon exercise of outstanding options under our 2019 Inducement Equity Incentive Plan, as of December 31, 2020 (the “Inducement Plan”). Descriptions of the 2015 Plan and the Inducement Plan are contained in Note 12 of the notes to our consolidated financial statements contained in our Annual Report on Form 10-K for the year ended December 31, 2020, filed with the SEC on March 19, 2021.

(5)Consists of the weighted-average exercise price of the 1,386,471 stock options outstanding on December 31, 2020.
(6)Consists of (i) 5,206 shares that remained available for future issuance under the 2015 Plan, as of December 31, 2020, (ii) 156,950 shares that remained available for future issuance under the Inducement Plan, as of December 31, 2020.
(7)The 2017 Plan has an evergreen provision, as amended, that allows for an annual increase in the number of shares available for issuance under the 2017 Plan to be added on the first day of each fiscal year, beginning with the fiscal year ended December 31, 2018 and continuing for each fiscal year until, and including, the fiscal year ending December 31, 2027,2027. The evergreen provides for an automatic increase in the number of shares available for issuance equal to the least of 1,025,490 shares of our common stock,(i) 4% of the number of shares of our common stock outstanding on the first day of the applicable fiscal yearsuch date and (ii) an amount determined by our board of directors. On January 1, 2019, 582,889 additional shares were reserved for issuance under the 2017 Plan pursuant to this provision. OurBoard. The 2017 ESPP has an evergreen provision that allows for an annual increase in the number of shares available for issuance under the 2017 ESPP to be added on the first day of each fiscal year, beginning on January 1, 2019 and ending on December 31, 2029, in an amount equal to the least of 512,745(i) 85,457 shares of our common stock, (ii) 2% of the total number of outstanding shares as of our common stock outstanding on the first day of the applicable fiscal yearsuch date and (iii) an amount determined by our board of directors. On January 1, 2019, 291,444 additional shares were reserved for issuance under the 2017 ESPP pursuant to this provision. In addition, upon the closing of the Merger on March 13, 2019, we assumed the X4 Plan. As of March 13, 2019, there were options to purchase an aggregate of 751,929 shares of common stock outstanding under the X4 Plan and 217,411 shares of our common stock reserved for future issuance under the X4 Plan.

Board.

REPORT OF AUDIT COMMITTEE

The audit committee


30


TRANSACTIONS WITH RELATED PERSONS AND INDEMNIFICATION
RELATED-PERSON TRANSACTIONS POLICY AND PROCEDURES
Our Board of our board of directors, which consists entirely of directors who meet the independence and experience requirements of the Nasdaq Stock Market, has furnished the following report:

The audit committee assists our board of directors in overseeing and monitoring the integrity of our financial reporting process, compliance with legal and regulatory requirements and the quality of internal and external audit processes. This committee’s role and responsibilities are set forth in our charter adopted by our board of directors, which is available on our website at www.x4pharma.com. This committee reviews and reassesses our charter annually and recommends any changes to our board of directors for approval. The audit committee is responsible for overseeing our overall financial reporting process, and for the appointment, compensation, retention, and oversight of the work of PricewaterhouseCoopers LLP. In fulfilling its responsibilities for the Arsanis, Inc., or Arsanis, financial statements for the fiscal year ended December 31, 2018, the audit committee of Arsanis took the following actions:

Reviewed and discussed the audited financial statements for the fiscal year ended December 31, 2018 with management and PricewaterhouseCoopers LLP, our independent registered public accounting firm;

Discussed with PricewaterhouseCoopers LLP the matters required to be discussed in accordance with Auditing Standard No. 1301—Communications with Audit committees; and

Received written disclosures and the letter from PricewaterhouseCoopers LLP regarding its independence as required by applicable requirements of the Public Company Accounting Oversight Board regarding PricewaterhouseCoopers LLP’s communications with the audit committee and the audit committee further discussed with PricewaterhouseCoopers LLP its independence. The audit committee of Arsanis also considered the status of pending litigation, taxation matters and other areas of oversight relating to the financial reporting and audit process that the committee determined appropriate.

Based on the Arsanis audit committee’s review of the audited financial statements and discussions with management and PricewaterhouseCoopers LLP, the Arsanis audit committee recommended to the Arsanis board of directors that the audited financial statements be included in the Arsanis Annual Report on Form10-K for the fiscal year ended December 31, 2018 for filing with the SEC.

Members of the X4 Pharmaceuticals, Inc. Audit Committee

David McGirr

Isaac Blech

Michael S. Wyzga

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, or the Exchange Act, whether made before or after the date hereof and irrespective of any general incorporation language in any such filing.

SECTION 16(a) BENEFICIAL OWNERSHIP REPORTING COMPLIANCE

Section 16(a) of the Securities Exchange Act of 1934, as amended, or the Exchange Act, requires our directors and executive officers, and persons who own more than ten percent 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. Officers, directors and greater than ten percent stockholders are required by SEC regulations to furnish us with copies of all Section 16(a) forms they file.

To our knowledge, based solely on a review of the copies of such reports furnished to us and written representations regarding the filing of required reports, we believe that all Section 16(a) filing requirements applicable to our directors, executive officers andgreater-than-ten-percent beneficial owners with respect to fiscal 2018 were met.

CERTAIN RELATIONSHIPS AND RELATED PERSON TRANSACTIONS

Policies and Procedures for Related Person Transactions

Our board of directorsDirectors has adopted a written related person transaction policy to set forth policies and procedures for the review of any transaction, arrangement or relationship in which our company is a participant, the amount involved exceeds $120,000, and one of our executive officers, directors, director nominees or 5% stockholders, or their immediate family members, each of whom we refer to as a “related person,” has a direct or indirect material interest.

If a related person proposes to enter into such a transaction, arrangement or relationship, which we refer to as a “related party transaction,” the related person must report the proposed related person transaction to our chief financialChief Financial officer. The policy calls for the proposed related person transaction to be reviewed and approved by our audit committee.Audit Committee. Whenever practicable, the reporting, review and approval will occur prior to entry into the transaction. If advance review and approval is not practicable, the committeeAudit Committee will review and, in its discretion, may ratify the related person transaction. The policy also permits the chairChair of the audit committeeAudit Committee to review and, if deemed appropriate, approve proposed related person transactions that arise between committeeAudit Committee meetings, subject to ratification by the committeeAudit Committee at its next meeting. Any related person transactions that are ongoing in nature will be reviewed annually.

A related person transaction reviewed under this policy will be considered approved or ratified if it is authorized by the audit committeeAudit Committee in accordance with the standards set forth in the policy after full disclosure of the related person’s interests in the transaction. As appropriate for the circumstances, the policy provides that the audit committeeAudit Committee will review and consider:

the related person’s interest in the related person transaction;

the approximate dollar value of the amount involved in the related person transaction;

the approximate dollar value of the amount of the related person’s interest in the transaction without regard to the amount of any profit or loss;

whether the transaction was undertaken in the ordinary course of our business;

whether the terms of the transaction are no less favorable to us than the terms that could have been reached with an unrelated third party;

the purpose of, and the potential benefits to us of, the transaction; and

any other information regarding the related person transaction or the related person in the context of the proposed transaction that would be material to investors in light of the circumstances of the particular transaction.

The audit committeeAudit Committee may approve or ratify the related person transaction only if the audit committeeAudit Committee determines that, under all of the circumstances, the transaction is in our best interests. The audit committeeAudit Committee may impose any conditions on the related person transaction as it deems appropriate. The policy also provides that transactions involving compensation of executive officers will be reviewed and approved by our compensation committeeCompensation Committee in the manner specified in its charter.

Related Person

For purposes of the policy, we refer to certain related-party transactions below in which (a) we were a participant, (b) the amount involved exceeded or will exceed $120,000 or, during such time as we qualify as a “smaller reporting company,” the lesser of (1) $120,000 or (2) 1% of the average of our total assets for the last two completed fiscal years, and (c) one or more related persons had a direct or indirect material interest. Transactions

In addition involving compensation for services provided to the compensation arrangements with directors and executive officers described elsewhereus by an employee, director, consultant or individual performing in a similar capacity by a related person are not covered by this proxy statement, sincepolicy.


CERTAIN RELATED-PERSON TRANSACTIONS
Since January 1, 2017,2019, we have engaged in, or currently propose to engage in, the following transactions in which the amount involved exceeds $120,000 and any of our executive officers, directors, director nominees or 5% stockholders, or their immediate family members, or any person who was in any of those categories at the time of such transaction, had or has a direct or indirect material interest.related-party transactions. We believe that all of these transactions were on terms comparable to terms that could have been obtained from unrelated third parties.

Arsanis Related Person Transactions

Services and Facilities Agreement with EveliQure Biotechnologies GmbH

Our subsidiary, Arsanis Biosciences GmbH, leases approximately 1,500 square meters of office and lab space from Marxbox Bauprojekt GmbH & Co. OG. In February 2015, Arsanis Biosciences GmbH entered into a services and facilities agreement with EveliQure Biotechnologies GmbH, or EveliQure, under which Arsanis provided certain laboratory services and sublet approximately 150 square meters of office and lab space. Tamás Henics, the husband of Eszter Nagy, Arsanis’s former Chief Scientific Officer and director, serves as Chief Scientific Officer at EveliQure.

On June 28, 2018 and in accordance with the terms of this agreement with EveliQure, Arsanis provided EveliQure with written notice that the services and facilities agreement will terminate and EveliQure will vacate the sublet space no later than December 

31 2018. As of December 31, 2018, Arsanis had vacated the office and lab space and its services and facilities agreement with EveliQure was terminated.

During the years ended December 31, 2018 and 2017, Arsanis received payments from EveliQure under the agreement of $0.2 million and less than $0.1 million, respectively. As of December 31, 2018 and 2017, amounts due from EveliQure totaled less than $0.1 million. These amounts included rental charges as well as amounts attributable to facilities and laboratory services.



Agreements with Adimab, LLC

Arsanis entered into two agreements with Adimab, LLC, or Adimab, the Adimab Collaboration Agreement and the Adimab Option Agreement, under which Arsanis was granted exclusive options to obtain ownership or exclusive worldwide licenses under specified patents relating to the development and commercialization of monoclonal antibodies. Tillman U. Gerngross, Ph.D., the former chairman of Arsanis’s board of directors, is aco-founder of Adimab and currently serves as its chief executive officer. The following descriptions of the agreements with Adimab are summaries and are qualified by reference to the underlying agreements.

Adimab Collaboration Agreement

In May 2011, Arsanis entered into a collaboration agreement with Adimab, which, as amended, and together with certain applicable option exercise letters Arsanis sent to Adimab, we refer to as the Adimab Collaboration Agreement. Under the Adimab Collaboration Agreement, Adimab and Arsanis were required to use reasonable efforts to conduct certain research, which Arsanis funded, to discover and optimize antibodies directed against targets selected by Arsanis. Prior to Arsanis’s exercise of an option, (1) Arsanis and Adimab each grant the other anon-exclusive license to the relevant intellectual property Arsanis owns to allow each party to carry out its rights and obligations in connection with the research, and (2) except for Adimab’s retained right to continue using and licensing its own libraries, each party agrees not to practice or license the patents arising out of the research that it owns for any purpose other than to carry out its rights and obligations in connection with the research.

With respect to each target that was the subject of the research, Arsanis had an exclusive option to obtain, with respect to a specified number of antibodies directed against such target and discovered or optimized by Adimab, (1) ownership of certain patent rights relating to such antibodies and (2) exclusive andnon-exclusive licenses, with the right to grant sublicenses, in all human therapeutic, prophylactic and diagnostic areas, which we refer to as the licensed field, under certain patent rights andknow-how, to research, develop, make, have made, use, sell, offer to sell, import and export such antibodies and products based on such antibodies (but not for antibody discovery purposes). In addition, upon exercise of each option, certain contractual restrictions on Arsanis’s ability to prosecute, practice and license certain patents owned by Arsanis that arose out of the research were eliminated. All of Arsanis’s options under the Adimab Collaboration Agreement have expired, or, with respect to multiple targets and hundreds of antibodies, have already been exercised.

Directors

Under the Adimab Collaboration Agreement, for each target for which Arsanis has exercised an option, we are required to use commercially reasonable efforts to develop and commercialize at least one product in major markets. If we do not fulfill these diligence obligations, Adimab may consider it a material breach, allowing Adimab to terminate the agreement with respect to such target and all associated products. We are obligated to pay Adimab royalties at amid-single-digit percentage of net sales, made by us or our affiliates, of products based on antibodies for which Arsanis exercised its option, or products that use or are based on any antibody discovered or optimized under the agreement, any derivative or modified version of any such antibody, or any sequence information as to any such antibody.

If we (or one of our affiliates with rights under the agreement) undergoes a change in control and, at the time of such change in control, we have not sold or licensed to third parties all of our rights in antibodies for which we are obligated to pay Adimab royalties under the agreement (which rights we refer to as undesignated rights), then we are obligated to either pay Adimab a percentage, in the mid double digits of the payments we receive from that change in control that are reasonably attributable to those undesignated rights and certain patents arising from the collaboration, or require our acquirer and all of its future third party collaborators to pay to Adimab the royalties described above with respect to net sales of all products based on those undesignated rights. As a result of the Merger, this royalty election was made by Arsanis. If we grant rights to a third party under certain patents that are not directed to the antibodies for which we are obligated to pay Adimab royalties, we are also obligated to pay Adimab, in place of royalties or a percentage of payments received from the third party, a lump sum in the high six digits.

If we sell or license to any third party, or otherwise grant rights to any third party to, any of the products for which we are obligated to pay Adimab royalties, either alone or as part of a package including specified patents not directed to these antibodies, we are obligated to pay Adimab either the same royalties on net sales of such products by such third party, or a percentage, ranging from the low double digits to a maximum of less than 30%, of the payments we receive from such third parties that are attributable to such grant of rights. In April 2017, Arsanis entered into a letter agreement with the Gates Foundation (described below), pursuant to which Arsanis licensed to the Gates Foundation certain rights under its ASN100 program.

Notwithstanding the payment obligations described above, we have no payment obligations under the Adimab Collaboration Agreement with respect to sales of certain antibody products if they are sold at cost in developing countries under Arsanis’s April 2017 letter agreement with the Bill & Melinda Gates Foundation. However, if such products are sold in developing countries for an amount that exceeds cost, then the amount of such excess over cost will be subject to the royalty payment obligations.

The Adimab Collaboration Agreement will expire on acountry-by-country basis twelve years after the first commercial sale in such country of the last product for which we are obligated to pay Adimab royalties in such country under the agreement. We have the right to terminate the agreement for any reason by providing Adimab with a specified amount of prior written notice. Adimab has the right to terminate the agreement if we materially breach the agreement. If Adimab terminates the agreement for our breach, or if we terminate the agreement for our convenience, then we must transfer or license to Adimab certain rights and assets relating to targets and antibodies for which Arsanis exercised its option. Adimab is then obligated to make payments to us with respect to these targets and antibodies that are similar to the payments we were required to make to Adimab during the term of the agreement. Certain of our payment obligations relating to specified products and patents arising from the agreement survive expiration or termination of the agreement. Under the Adimab Collaboration Agreement, as of December 31, 2018, Arsanis had paid Adimab approximately $4.3 million in the aggregate, consisting of upfront payments and reimbursement for research conducted by Adimab.

Adimab Option and License Agreement

In February 2017, Arsanis entered into an option and license agreement with Adimab, which we refer to as the Adimab Option Agreement. Under the Adimab Option Agreement, Adimab has provided to us certain

proprietary antibodies against respiratory syncytial virus, or RSV, which we refer to as the initial RSV antibodies, for our evaluation during a specified option period and has granted us an exclusive, non-sublicensable license under certain Adimab patent rights andknow-how during the option period to create, research, optimize, make, have made and use the initial RSV antibodies and modified or derivative forms of the initial RSV antibodies.

Under the Adimab Option Agreement, we have an exclusive option, exercisable during the option period upon payment of an option fee to Adimab, to require Adimab to assign to us all rights in up to a specified number of RSV antibodies selected by us, which we refer to as the selected RSV antibodies, and certain patent rights owned by Adimab that cover these antibodies, and to obtain from Adimab anon-exclusive license, with the right to grant sublicenses, under certain other patent rights andknow-how owned by Adimab, to research, develop, have developed, make, have made, use, sell, offer to sell, import and export products based on the selected RSV antibodies and modified or derivative forms of the selected RSV antibodies, for all indications and uses except for certain diagnostic uses. If we exercise our option under the agreement, we would be required to use commercially reasonable efforts to develop and commercialize at least one product based on a licensed RSV antibody in major markets.

If we wish to exercise our option under the Adimab Option Agreement, we will be obligated to pay Adimab an option fee of $0.3 million and make clinical and regulatory milestone payments of up to $24.4 million. We are obligated to pay Adimab royalties at amid-single-digit percentage of net sales of products based on the initial RSV antibodies (including modified or derivative forms of those antibodies created by or for us) by us or any of our affiliates, licensees or sublicensees, regardless of whether these products practice any of the assigned or licensed patents orknow-how, subject to certainoff-set rights and adjustments to the royalty payments described in the agreement, and subject to further carve-outs with respect to sales of products based on licensed RSV antibodies to the extent they are sold at cost in developing countries under the February 2017 Bill & Melinda Gates Foundation, or Gates Foundation, grant agreement, as amended and restated in August 2018, and the August 2018 Gates Foundation grant agreement (described below). However, if such products are sold in developing countries for an amount that exceeds cost, then the amount of such excess will be subject to the royalty payment obligations described in the preceding paragraph.

If we do not exercise our option, the Adimab Option Agreement will expire on our achievement of specified preclinical milestones under our grant agreement with the Gates Foundation, but in any event no later thanmid-2019. We have the right to terminate the Adimab Option Agreement for any reason by providing Adimab with a specified amount of prior written notice. Adimab has the right to terminate the agreement if we materially breach the agreement. If Adimab terminates the agreement for our breach, if we terminate the agreement for our convenience or if the agreement expires before we exercises our option, then we must return or destroycertain know-how, including all initial RSV antibodies, and all modified or derivative forms of those antibodies, in our possession other than those for which we have made all payments required under the agreement, assign certain patents covering certain RSV antibodies to Adimab, grant Adimaba non-exclusive, royalty-free license under certain other patents, and grant Adimab a time-limited right of first negotiation to obtain an exclusive license to certain patentsand know-how and the transfer and assignment of certain regulatory filings and approvals and other related assets related to products based on licensed RSV antibodies. Certain of our payment obligations relating to specified products arising from the agreement survive expiration or termination of the agreement. During the years ended December 31, 2018 and 2017, Arsanis made payments to Adimab of $0.1 million and $0.1 million, respectively, under the Adimab Option Agreement.

Agreements with Bill & Melinda Gates Foundation

February 2017 Grant Agreement and August 2018 Amended and Restated Gates Foundation Grant Agreement

In February 2017, Arsanis entered into a grant agreement with the Gates Foundation pursuant to which the Gates Foundation granted Arsanis up to $9.3 million to conduct preclinical development of monoclonal

antibodies for the prevention of RSV infection in newborns, which we refer to as the RSV project. In return, Arsanis agreed to conduct the RSV project in a manner that ensures that the knowledge and information gained from the project will be promptly and broadly disseminated, and that the products, technologies, materials, processes and other intellectual property resulting from the RSV project (which Arsanis collectively refers to as the funded developments) will be made available and accessible at an affordable price to people most in need within developing countries. These obligations survive any expiration or termination of the grant agreement.

To this end, Arsanis granted the Gates Foundationa non-exclusive, perpetual, royalty-free, fully paid up, sublicensable license to make, use, sell, offer to sell, import, distribute, copy, modify, create derivative works, publicly perform and display the funded developments and, to the extent incorporated into a funded development or required to use a funded development, any other technology created outside of the RSV project that was used as part of the RSV project, for the benefit of people in developing countries. Arsanis also agreed to seek prompt publication of data and results developed under the RSV project under “open access” terms and conditions. This license and these publication obligations survive any expiration or termination of the grant agreement.

The grant agreement expires on October 31, 2019. The Gates Foundation can modify, suspend or discontinue any payment under the grant agreement, or terminate the grant agreement, if it is not reasonably satisfied with Arsanis’s progress on the RSV project; if there are significant changes to Arsanis’s leadership or other factors that the Gates Foundation reasonably believes may threaten the RSV project’s success; if Arsanis undergoes a change in control; if there is a change in its tax status; if the RSV project is no longer aligned with the Gates Foundation’s programmatic strategy; or if Arsanis fails to comply with the grant agreement. Any grant funds that have not been used for, or committed to, the RSV project upon the expiration or termination of the agreement must be returned to the Gates Foundation or otherwise used as directed by the Gates Foundation. In August 2018, Arsanis amended and restated the February 2017 grant agreement. The amended and restated grant agreement includes amendments to conform to current Gates Foundation audit, reporting, and other administrative requirements, as well as to make the perpetual Gates Foundation license grant described above irrevocable.

During the years ended December 31, 2018 and 2017, Arsanis recognized grant income of $0 and $1.6 million, respectively, under the grant agreement with the Gates Foundation upon incurring qualifying expenses. As of December 31, 2018 and 2017, there were no amounts recorded as unearned income under the grant agreement with the Gates Foundation.

August 2018 Gates Foundation Grant Agreement

In August 2018, Arsanis entered into an additional grant agreement with the Gates Foundation pursuant to which the Gates Foundation granted to Arsanis up to $1.1 million to conduct preclinical development activities for the RSV project that were not included in the February 2017 grant agreement, as amended and restated in August 2018. In return, Arsanis agreed to conduct the RSV project in a manner that ensures that the knowledge and information gained from the project will be promptly and broadly disseminated, and that the products, technologies, materials, processes and other intellectual property resulting from the RSV project (collectively referred to as the funded developments) will be made available and accessible at an affordable price to people most in need within developing countries. These obligations survive any expiration or termination of the grant agreement.

To this end, Arsanis granted to the Gates Foundationa non-exclusive, perpetual, irrevocable, royalty-free, fully paid up, sublicensable license to make, use, sell, offer to sell, import, distribute, copy, modify, create derivative works, publicly perform and display the funded developments and, to the extent incorporated into a funded development or required to use a funded development, any other technology created outside of the RSV project that was used as part of the RSV project, for the benefit of people in developing countries. Arsanis also agreed to seek prompt publication of data and results developed under the RSV project under “open access” terms and conditions. This license and these publication obligations survive any expiration or termination of the grant agreements.

During the year ended December 31, 2018, Arsanis recognized grant income of $1.1 million under the August 2018 grant agreement with the Gates Foundation upon incurring qualifying expenses. Accordingly, unearned income under the August 2018 grant agreement with the Gates Foundation was $0 as of December 31, 2018. The August 2018 grant agreement expired during the year ended December 31, 2018.

Gates Foundation Letter Agreement and Investment

In April 2017, Arsanis entered into a letter agreement with the Gates Foundation. In connection with the letter agreement, the Gates Foundation purchased 2,464,799 shares of Arsanis’s Series D redeemable convertible preferred stock (the “Series D preferred stock”), which converted into 120,363 shares of Arsanis’s common stock in connection with Arsanis’s initial public offering after giving effect to aone-for-3.4130 reverse stock split and the Reverse Stock Split. Arsanis committed to use the proceeds of $8.0 million from the investment by the Gates Foundation solely to advance the development of a specified monoclonal antibody program that involved the monoclonal antibodiesASN-1,ASN-2 andASN-3 and Arsanis’s product candidate, ASN100. Under the letter agreement, in addition to the initial project funded by the Gates Foundation with its initial investment, Arsanis also agreed to conduct up to four additional projects to be proposed and to be funded by the Gates Foundation.

The letter agreement contains certain global access obligations as well as requirements relating to Arsanis’s use of the funds received from the Gates Foundation investment. In the event that we fail to comply with these obligations or requirements or any related U.S. legal obligations set forth in the letter agreement, the Gates Foundation will have the right, after expiration of a specified cure period, to require us to redeem all of the shares owned by the Gates Foundation or to locate a third party that will purchase such shares. For any redemption or purchase resulting from such default, the shares of our stock held by the Gates Foundation will be redeemed at an amount equal to the greater of the original purchase price (plus specified interest) or the fair market value of such stock on the date of such redemption. The term of the letter agreement continues in perpetuity.

In connection with this letter agreement, Arsanis granted to the Gates Foundation and/or Gates Foundation-supported entities certain licenses, including anon-exclusive,non-terminable, royalty-free (except as required under the Adimab Collaboration Agreement), sublicensable license to products, technologies, materials, processes and other intellectual property developed using funds provided by the Gates Foundation or a Gates Foundation-supported entity, or developed in connection with Arsanis’s conduct of any funded project or additional funded project, as well as all of Arsanis’s background intellectual property, to utilize and exploit products and services directed at pathogens or other targets subject to any funded project or additional funded project.

The proceeds received from the Gates Foundation in connection with Arsanis’s sale and issuance of Series D preferred stock were incurred on qualifying expenses under the letter agreement during the year ended December 31, 2017. During the years ended December 31, 2018 and 2017, Arsanis incurred qualifying expenses of $0 and $8.0 million, respectively, under the letter agreement with the Gates Foundation.

Arsanis 2017 Convertible Note Financing

In January 2017, Arsanis issued and sold an aggregate of $4,934,981 in convertible promissory notes, or the 2017 Notes. The 2017 Notes accrued interest at a rate of 0.96% per annum, with a maturity date of October 12, 2017, unless earlier converted under the terms of the 2017 Notes. All principal and interest accrued under the 2017 Notes was converted into shares of Arsanis Series D convertible preferred stock in connection with the closing of Arsanis’s Series D convertible preferred stock financing in April 2017. Upon completion of Arsanis’s initial public offering in November 2017, all the outstanding shares of Arsanis Series D convertible preferred stock automatically converted into shares of Arsanis common stock. The following table sets forth the aggregate principal amount of notes issued and sold to Arsanis’s 5% stockholders and their affiliates in this transaction and the cash purchase price for such notes:

Name

  Aggregate Principal
Amount of 2017
Notes
  Cash
Purchase
Price

Entities affiliated with Polaris Venture Partners (1)

   $1,294,943   $1,294,943

Entities affiliated with SV Health Investors, LLC (2)

   $1,294,943   $1,294,943

OrbiMed Private Investments IV, LP (3)

   $1,294,943   $1,294,943

NeoMed Innovation V, L.P. (4)

   $565,147   $565,147

Tillman U. Gerngross, Ph.D. (5)

   $250,000   $250,000

(1)

Terrance McGuire and Amy Schulman were members of Arsanis’s board of directors and each is an affiliate of Polaris Venture Partners.

(2)

Michael Ross was a member of Arsanis’s board of directors who is an affiliate of SV Health Investors, LLC.

(3)

Carl Gordon was a member of Arsanis’s board of directors who is an affiliate of OrbiMed Private Investments IV, LP.

(4)

Claudio Nessi was a member of Arsanis’s board of directors who is an affiliate of NeoMed Innovation V, L.P.

(5)

Tillman U. Gerngross is the former chairman of Arsanis’s board of directors.

Arsanis Series D Preferred Stock Financing

In April 2017, Arsanis issued and sold an aggregate of 14,220,284 shares of its Series D convertible preferred stock, consisting of (i) 12,323,987 shares sold for an aggregate of $35,053,178 in cash and conversion of $4,946,793 in outstanding principal and interest under the 2017 Notes at a price per share of approximately $3.2457 and (ii) 1,896,297 shares issued upon conversion of $5,539,344 in outstanding principal and interest under convertible promissory notes issued in April 2016, or the 2016 Notes, at a price per share of approximately $2.92. Upon completion of Arsanis’s initial public offering in November 2017, all the outstanding shares of Series D convertible preferred stock automatically converted into shares of Arsanis common stock. The following table sets forth the aggregate numbers of shares of Arsanis’s Series D convertible preferred stock that Arsanis sold to its 5% stockholders and their affiliates in these transactions and the aggregate amount of consideration for such shares:

Name

 Shares of Series D
Preferred Stock
Issued for Cash
and upon
Conversion of
2017 Notes
 Cash
Purchase
Price
 Principal
Cancelled
under
2017
Notes
 Interest
Cancelled
under
2017 Notes
 Shares of Series D
Preferred
Stock
Issued upon
Conversion
of 2016 Notes
 Principal
Cancelled
under
2016
Notes
 Interest
Cancelled
Under
2016 Notes

Bill & Melinda Gates Foundation

   2,464,799  $7,999,998   —     —     —     —     —  

Entities affiliated with Polaris Venture Partners (2)

   1,924,752  $4,949,125  $1,294,943  $3,099   307,259  $891,178  $6,375

Entities affiliated with SV Health Investors, LLC (3)

   1,924,750  $4,949,125  $1,294,943  $3,099   307,262  $891,178  $6,375

OrbiMed Private Investments IV,
LP (4)

   1,924,752  $4,949,125  $1,294,943  $3,099   307,262  $891,178  $6,375

NeoMed Innovation V, L.P. (5)

   839,938  $2,159,687  $565,147  $1,353   112,559  $326,467  $2,335

Tillman U. Gerngross, Ph.D. (6) 

   308,099  $749,399  $250,000  $598   —     —     —  

(1)

Terrance McGuire and Amy Schulman were members of Arsanis’s board of directors and each is an affiliate of Polaris Venture Partners.

(2)

Michael Ross was a member of Arsanis’s board of directors who is an affiliate of SV Health Investors, LLC.

(3)

Carl Gordon was a member of Arsanis’s board of directors who is an affiliate of OrbiMed Private Investments IV, LP.

(4)

Claudio Nessi was a member of Arsanis’s board of directors who is an affiliate of NeoMed Innovation V, L.P.

(5)

Tillman U. Gerngross was the chairman of Arsanis’s board of directors.

Arsanis’s Initial Public Offering

In November 2017, Arsanis completed its initial public offering under which Arsanis issued and sold an aggregate of 4,600,000 shares of its common stock at a price per share of $10.00, for an aggregate purchase price of $46.0 million. The following table sets forth the number of shares of our common stock purchased by our directors, executive officers and 5% stockholders and their affiliates in the initial public offering and the aggregate purchase price paid for such shares. The share and per share amounts described in this section “Arsanis’s Initial Public Offering” do not reflect the Reverse Stock Split.

Name

  Shares of Common
Stock Purchased
  Aggregate
Purchase Price

Entities affiliated with Polaris Venture Partners (1)

    500,000   $5,000,000

Entities affiliated with SV Health Investors, LLC (2)

    500,000   $5,000,000

OrbiMed Private Investments IV, LP (3)

    500,000   $5,000,000

NeoMed Innovation V, L.P. (4)

    300,000   $3,000,000

Tillman U. Gerngross, Ph.D. (5)

    200,000   $2,000,000
   

 

 

    

 

 

 

Total

    2,000,000   $20,000,000
   

 

 

    

 

 

 

(1)

Terrance McGuire and Amy Schulman were members of Arsanis’s board of directors and each is an affiliate of Polaris Venture Partners.

(2)

Michael Ross was a member of Arsanis’s board of directors who is an affiliate of SV Health Investors, LLC.

(3)

Carl Gordon was a member of Arsanis’s board of directors who is an affiliate of OrbiMed Private Investments IV, LP.

(4)

Claudio Nessi was a member of Arsanis’s board of directors who is an affiliate of NeoMed Innovation V, L.P.

(5)

Tillman U. Gerngross was the chairman of Arsanis’s board of directors.

X4 Related Person Transactions

X4 Series B Preferred Stock Financing

Since November 2017, X4 issued an aggregate of 18,616,569 shares of X4 Series B preferred stock at $1.88 per share and warrants to purchase an aggregate of 3,504,906 shares of X4 Series B preferred stock for an aggregate purchase price of approximately $35.0 million, which is referred to as the Series B preferred stock financing. Each share of X4 Series B preferred stock converted automatically into the right to receive shares of our common stock based on the exchange ratio immediately prior to the Merger.

The following table summarizes the Series B preferred stock and warrants to purchase Series B preferred stock purchased by X4’s directors, executive officers and principal stockholders at the time of the Series B preferred stock financing.

Name of Purchaser

 Number of
Shares of
Series B
Preferred
Stock
Purchased
  Warrants
to Purchase
the
Number of
Shares of
Series B
Preferred
Stock
Listed
Below
  Exercise
Price of
Warrants
  Aggregate
Purchase
Price
  Date of
Purchase
 Expiration
Date of
Warrants

Entities affiliated with Cormorant (1)

 

 

1,329,788

 

 

 

132,979

 

 

$

1.88

 

 

$

2,500,000

 

 November 1,
2017
 November 1,

2020

Healthcare Industry (Cayman) A Co., Limited

 

 

2,659,574

 

 

 

265,957

 

 

$

1.88

 

 

$

5,000,000

 

 September 12,
2018
 September 12,

2021

(1)

Consists of 1,094,149 shares of X4 Series B preferred stock and warrants to purchase 109,415 shares of X4 Series B preferred stock issued to Cormorant Private Healthcare Fund I, L.P., 191,490 shares of X4 Series B preferred stock and warrants to purchase 19,149 shares of X4 Series B preferred stock issued to Cormorant Global Healthcare Master Fund, L.P., and 44,149 shares of X4 Series B preferred stock and warrants to purchase 4,415 shares of X4 Series B preferred stock issued to CRMA SPV, L.P.

X4 also paid Maxim Partners LLC, or Maxim, fees and reimbursement of expenses of approximately $2.8 million as placement agent for the Series B preferred stock financing, pursuant to a letter agreement between X4 and Maxim, dated as of July 6, 2017, as amended on February 13, 2018. As additional compensation, X4 issued warrants to purchase shares of X4 Series B preferred stock to Maxim. The first warrant was issued on December 28, 2017, was exercisable for 1,219,815 shares of X4 Series B preferred stock, had an exercise price of $1.88 per share, and expires on December 28, 2027. The second warrant was issued on September 12, 2018, was exercisable for 212,765 shares of X4 Series B preferred stock, had an exercise price of $1.88 per share, and expires on September 12, 2028. The letter agreement was terminated, effective as of May 16, 2018. In connection with the termination of the letter agreement, X4 agreed to pay Maxim a fee of $25,000 for expenses incurred after December 31, 2017. In addition, X4 and Maxim agreed that if, within 12 months of termination of the letter agreement, we complete a private financing or capital raising activity with certain other qualified investors, X4 would be required to pay Maxim certain agreed upon fee amounts. In connection with the Merger, the warrants exercisable for X4 Series B preferred stock became warrants to exercisable for our common stock at an agreed upon exchange ratio. The exercise price was also adjusted according to the exchange ratio.

X4 Series Seed Preferred Stock Repurchase

In October 2017, X4 entered into a stock repurchase agreement with the Estate of Henri Termeer (the “Termeer Estate”), a founder of X4, pursuant to which X4 agreed to repurchase 598,975 shares of X4 Series Seed preferred stock from the Termeer Estate at an aggregate repurchase price of $1,126,073. Alan E. Walts, Ph.D., a former director of X4 elected by the holders of X4 Series Seed preferred stock, serves as a business advisor to the Termeer Estate and receives a monthly consulting fee for such services. Dr. Walts does not have any voting or investment control over the securities held by the Termeer Estate and recused himself from the discussions with respect to this repurchase. The repurchase was settled in January 2018.

X4 Investors’ Rights, Votingand Co-sale Agreements

In connection with X4’s preferred stock financings, X4 entered into investors’ rights, voting and right of first refusaland co-sale agreements containing registration rights, information rights, voting rights and rights of first refusal, among other things, with certain holders of X4 preferred stock and certain holders of X4 common stock. In accordance with and pursuant to the terms of the Merger Agreement, these stockholder agreements terminated upon the closing of the Merger.

X4 Agreements with X4 Directors

Gary J. Bridger, Ph.D.

On November 14, 2017, X4September 17, 2020, we entered into an independent contractor agreement with Gary J. Bridger, Ph.D., pursuant to which Dr. Bridger agreedwas entitled to provide X4 with strategic advice in supportreceive $30,000 per month and a non-qualified stock option to purchase 30,000 shares of our research and development programscommon stock in oncology and WHIM syndrome. The agreement provided for an initial termconsideration of six months, which was renewed in accordance with its terms for an additional six months and expired in November 2018. The independent contractor agreement included standard assignmenthis performance of invention, confidentiality and indemnification provisions. In consideration for the provision ofcertain consulting services pursuant to us during the agreement, Dr. Bridger was paid approximately $105,000.

On October 4, 2018, X4 entered into a letter agreement with Dr. Bridger, pursuantperiod from September 17, 2020 to which Dr. Bridger agreed to serve as a member of the board of directors of X4. This letter agreement superseded the independent contractor agreement described above. Pursuant to the letter agreement, X4December 17, 2020. We granted Dr. Bridger an option to purchase 226,98330,000 shares of X4our common stock to vestat a strike price of $7.33 on October 5, 2020.


Murray Stewart, M.D.
On September 17, 2020, we entered into an independent contractor agreement with Murray Stewart M.D., pursuant to the terms of the X4 Plan and a separatenon-qualified stock option agreement. The letter agreement also specified thatwhich Dr. Bridger would beStewart was entitled to receive an annual grant$450 per hour and a non-qualified stock option to purchase 10,000 shares of our common stock in consideration of his performance of certain consulting services to us during the period from September 17, 2020 to September 17, 2021. We granted Dr. Stewart an option to purchase shares of X4 common stock at the level set for independent directors by the board of directors, if any. X4 also agreed to reimburse Dr. Bridger for expenses for which he received prior approval. Either X4 or Dr. Bridger may terminate the letter agreement at any time, for any reason, by giving the other 30 days’ prior written notice. In connection with the Merger, the option to purchase shares of X4 common stock became an option to purchase10,000 shares of our common stock.

Alan E. Walts, Ph.D.

On November 27, 2016, X4 entered into a letter agreement with its former director Alan E. Walts, Ph.D. to outline the applicable terms of his role as a member of the X4 board of directors. Pursuant to the letter agreement, X4 and Dr. Walts acknowledged that X4 had previously granted Dr. Walts an option to purchase 70,000 shares of X4 common stock at an exercisea strike price of $0.65 per share, to vest pursuant to the terms of the X4 Plan and a separatenon-qualified stock option agreement previously entered into by and between X4 and Dr. Walts. The letter agreement also specified that Dr. Walts would be entitled to receive an annual grant of an option to purchase shares of X4 common stock at the level set for independent directors by the X4 board of directors, if any. X4 also agreed to reimburse Dr. Walts for expenses for which he received prior approval from X4. The letter agreement included standard assignment of invention and confidentiality provisions. Either X4 or Dr. Walts was entitled to terminate the letter agreement at any time, for any reason, by giving the other 30 days’ prior written notice. Dr. Walts resigned as a director of X4 upon the completion of the Merger.

Michael Gilman, Ph.D.

On November 27, 2016, X4 entered into a letter agreement with its former director Michael Gilman to outline the applicable terms of his role as a member of the X4 board of directors. Pursuant to the letter agreement, X4 and Dr. Gilman acknowledged that X4 had previously granted Dr. Gilman options to purchase 70,000 and 8,000 shares of X4 common stock, at an exercise price of $0.65 per share, to vest pursuant to the terms of the X4 Plan and a separatenon-qualified stock option agreement previously entered into by and between X4 and Dr. Gilman. The letter agreement also specified that Dr. Gilman would be entitled to receive an annual

grant of an option to purchase shares of X4 common stock at the level set for independent directors by the X4 board of directors, if any. X4 also agreed to reimburse Dr. Gilman for expenses for which he receives prior approval from X4. The letter agreement included standard assignment of invention, confidentiality and indemnification provisions. Either X4 or Dr. Gilman was entitled to terminate the letter agreement at any time, for any reason, by giving the other 30 days’ prior written notice. Dr. Gilman resigned as a director of X4 upon the completion of the Merger.

Nancy Lurker

On September$7.27 on October 20, 2016, X4 entered into a letter agreement with its former director Nancy Lurker pursuant to which Ms. Lurker agreed to serve as Chairwoman of the X4 board of directors. Pursuant to the letter agreement, X4 granted Ms. Lurker an option to purchase 175,000 shares of X4 common stock to vest pursuant to the terms of the X4 Plan and a separate2020.

non-qualified
stock option agreement previously entered into by and between X4 and Ms. Lurker. The letter agreement also specified that Ms. Lurker would be entitled to receive an annual grant of an option to purchase shares of X4 common stock at the level set for independent directors by the X4 board of directors, if any. X4 also agreed to reimburse Ms. Lurker for expenses for which she received prior approval from X4. The letter agreement included standard assignment of invention, confidentiality and indemnification provisions. Either X4 or Ms. Lurker was entitled to terminate the letter agreement at any time, for any reason, by giving the other 30 days’ prior written notice. Ms. Lurker resigned from the X4 board of directors as of January 21, 2018.

Shares of Our Common Stock Issued in the Merger

On March 13, 2019, we completed the Merger and effected the Reverse Stock Split. In connection with the Merger, Paula Ragan, Ph.D., our President and Chief Executive Officer, received 181,366 shares of common stock in exchange for 1,870,000 shares of Private X4 common stock and 38,451 shares of Private X4 Series Seed preferred stock, as adjusted for the Reverse Stock Split. In addition, the following table sets forth the options to purchase Private X4 common stock held by our directors and executive officers that became exercisable for our common stock in connection with the Merger:

Name

  Number of
Shares of X4

Common
Stock
Underlying
X4 Options (#)
  X4 Option
Exercise
Price ($)
  Number of
Shares  of

Post-Merger
Common
Stock
Underlying

Post-Merger
Options (#)
  Post-
Merger

Option
Exercise
Price ($)

Paula Ragan, Ph.D.

    1,059,935    0.65    100,729    6.84
    688,500    0.65    65,430    6.84
    843,496    0.67    80,160    7.08

Adam S. Mostafa

    659,067    0.99    62,633    10.44

Michael S. Wyzga

    740,000    0.99    70,324    10.44

Isaac Blech

    744,967    0.65    70,796    6.84

Gary J. Bridger, Ph.D.

    226,983    0.99    21,570    10.44

PROPOSAL NO. 1:

ELECTION OF DIRECTORS

On May 13, 2019,

Name  Number of
Shares of X4
Common Stock
Underlying
Private
X4 Options (#)
   Private
X4 Option
Exercise
Price ($)
   Number of
Shares of
Post-Merger
Common Stock
Underlying
Post-Merger
Options (#)
   Post-
Merger
Option
Exercise
Price ($)
 
Paula Ragan, Ph.D.   1,059,935    0.65    100,729    6.84 
   688,500    0.65    65,430    6.84 
   843,496    0.67    80,160    7.08 
Adam S. Mostafa   659,067    0.99    62,633    10.44 
Michael S. Wyzga   740,000    0.99    70,324    10.44 
Isaac Blech   744,967    0.65    70,796    6.84 
Gary J. Bridger, Ph.D.   226,983    0.99    21,570    10.44 


INDEMNIFICATION
We provide indemnification for our boarddirectors and executive officers so that they will be free from undue concern about personal liability in connection with their service to us. Under our Bylaws, we are required to indemnify our directors and executive officers to the extent not prohibited under Delaware or other applicable law. We has also entered into indemnity agreements with certain officers and directors. These agreements provide, among other things, that we will indemnify the officer or director, under the circumstances and to the extent provided for in the agreement, for expenses, damages, judgments, fines and settlements he or she may be required to pay in actions or proceedings which he or she is or may be made a party by reason of directors nominated René Russo for election at the annual meeting. Our board of directors currently consists of seven (7) members, classified into three classes as follows: René Russo and Isaac Blech constitute Class II, with a term ending at the 2019 annual meeting of stockholders; Gary J. Bridger, Ph.D. and Murray Stewart, M.D. constitute Class III, with a term ending at the 2020 annual meeting of stockholders; and Paula Ragan, Ph.D., Michael S. Wyzga and David McGirr constitute Class I, with a term ending at the 2021 annual meeting of stockholders. Mr. Blech will continue to servehis or her position as a director, officer or other agent of the Company, and otherwise to the fullest extent permitted under Delaware law and our Bylaws.

32


HOUSEHOLDING OF PROXY MATERIALS
The SEC has adopted rules that permit companies and intermediaries (e.g., brokers) to satisfy the delivery requirements for Notices of Internet Availability of Proxy Materials or other Annual Meeting materials with respect to two or more stockholders sharing the same address by delivering a single Notice of Internet Availability of Proxy Materials or other Annual Meeting materials addressed to those stockholders. This process, which is commonly referred to as “householding,” potentially means extra convenience for stockholders and cost savings for companies.
This year, a number of brokers with account holders who are X4 stockholders will be “householding” the Company’s proxy materials. A single Notice of Internet Availability of Proxy Materials will be delivered to multiple stockholders sharing an address unless contrary instructions have been received from the affected stockholders. Once you have received notice from your broker that they will be “householding” communications to your address, “householding” will continue until you are notified otherwise or until you revoke your consent. If, at any time, you no longer wish to participate in “householding” and would prefer to receive a separate Notice of Internet Availability of Proxy Materials, please notify your broker or X4. Direct your written request to X4 Pharmaceuticals, Inc., Attn: Corporate Secretary, 61 North Beacon Street, 4th Floor, Boston, MA 02134 or contact the endCorporate Secretary at (857) 529-8300. Stockholders who currently receive multiple copies of his term, which concludesthe Notices of Internet Availability of Proxy Materials at their addresses and would like to request “householding” of their communications should contact their brokers.

33


OTHER MATTERS
The Board of Directors knows of no other matters that will be presented for consideration at the annual meeting, upon whichAnnual Meeting. If any other matters are properly brought before the sizeAnnual Meeting, it is the intention of our board will be reduced to consist of six (6) members.

At each annual meeting of stockholders, directors are elected for a full term of three years to succeed those directors whose terms are expiring.

Our board of directors has voted to nominate René Russo for election at the annual meeting for a term of three years to serve untilpersons named in the 2022 annual meeting of stockholders, and until her successor is elected and qualified. The Class III directors (Gary J. Bridger, Ph.D. and Murray Stewart, M.D.) and the Class I directors (Paula Ragan, Ph.D., Michael S. Wyzga and David McGirr) will serve until the annual meetings of stockholders to be held in 2020 and 2021, respectively, and each director will hold office until his or her successor has been elected and qualified or until his or her earlier death, resignation or removal.

Unless authorityaccompanying proxy to vote for the nominee is withheld, the shares represented by the enclosed proxy will be votedFOR the election of René Russo as a director. In the event that Ms. Russo becomes unable or unwilling to serve, the shares represented by the enclosed proxy will be voted for the election ofon such other person as our board of directors may recommendmatters in the nominee’s place. We have no reason to believe that the nominee will be unable or unwilling to serve as a director.

accordance with their best judgment.

By Order of the Board of Directors,
image_611.jpg
Paula Ragan
President, Chief Executive Officer, Corporate Secretary and Director
April 20, 2021
A pluralitycopy of the shares votedFORCompany’s Annual Report to the nominee at the annual meeting is required to elect the nominee as a director.

THE BOARD OF DIRECTORS RECOMMENDS THE ELECTION OF RENÉ RUSSO AS A DIRECTOR, AND PROXIES SOLICITED BY THE BOARD OF DIRECTORS WILL BE VOTED IN FAVOR THEREOF UNLESS A STOCKHOLDER HAS INDICATED OTHERWISE ON THE PROXY.

PROPOSAL NO. 2:

RATIFICATION OF APPOINTMENT OF INDEPENDENT REGISTERED PUBLIC

ACCOUNTING FIRM

The audit committee has appointed PricewaterhouseCoopers LLP, as our independent registered public accounting firm, to audit our financial statementsSecurities and Exchange Commission on Form 10-K for the fiscal year ending December 31, 2019. The board of directors proposes that the stockholders ratify this appointment. PricewaterhouseCoopers LLP audited our financial statements for the fiscal years ended December 31, 2018 and 2017 and audited the financial statements of X4 for the fiscal years ended December 31, 2018 and 2017. We expect that representatives of PricewaterhouseCoopers LLP will be present at the annual meeting, will be able to make a statement if they so desire, and will be2020 is available to respond to appropriate questions.

In deciding to appoint PricewaterhouseCoopers LLP, the audit committee reviewed auditor independence issues with PricewaterhouseCoopers LLP and concluded that PricewaterhouseCoopers LLP has no commercial relationship with the Company that would impair its independence for the fiscal year ending December 31, 2019.

Arsanis Audit Fees and Services

The following table presents fees for professional audit services rendered by PricewaterhouseCoopers LLP for the audit of Arsanis’s annual financial statements for the years ended December 31, 2018 and December 31, 2017 as well as fees billed for other services rendered by PricewaterhouseCoopers LLP during those periods.

Fee Category  2018  2017

Audit Fees (1)

   $731,372   $1,437,218

Audit-Related Fees (2)

    —      —  

Tax Fees (3)

    —      —  

All Other Fees (4)

    1,800    —  
   

 

 

    

 

 

 

Total Fees

   $733,172   $1,437,218
   

 

 

    

 

 

 

(1)

“Audit Fees” consist of fees billed for professional services performed by PricewaterhouseCoopers LLP for the audit of Arsanis’s annual financial statements, the review of interim financial statements, and related services that are normally provided in connection with registration statements. Included in 2017 Audit Fees are fees of $926,309 billed in connection with Arsanis’s initial public offering, which closed in November 2017, and fees billed in connection with the filing of registration statements. Included in 2018 Audit Fees are fees of $188,372 billed in connection with the filing of registration statements.

(2)

“Audit-Related Fees” consist of fees billed by an independent registered public accounting firm for assurance and related services that are reasonably related to the performance of the audit or review of Arsanis’s financial statements and which are not reported under “Audit Fees.” There were no such fees incurred in 2018 or 2017.

(3)

“Tax Fees” consist of fees primarily related to tax compliance and consulting. There were no such fees incurred in 2018 or 2017.

(4)

“All Other Fees” relate to fees for access to the PricewaterhouseCoopers LLP online accounting research and financial disclosure tools.

There were no services that were approved by the audit committee pursuant to Rule2-01(c)(7)(i)(C) (relating to the approval of ade minimis amount ofnon-audit services after the fact but before completion of the audit).

X4 Audit Fees and Services

The following table presents fees for professional audit services rendered by PricewaterhouseCoopers LLP for the audit of X4’s annual financial statements for the years ended December 31, 2018 and December 31, 2017 as well as fees billed for other services rendered by PricewaterhouseCoopers LLP during those periods.

Fee Category  2018  2017

Audit Fees (1)

   $1,112,232   $185,000

Audit-Related Fees (2)

    —      —  

Tax Fees (3)

    8,150    7,250

All Other Fees (4)

    900    —  
   

 

 

    

 

 

 

Total Fees

   $1,121,282   $192,250
   

 

 

    

 

 

 

(1)

“Audit Fees” consist of fees billed for professional services performed by PricewaterhouseCoopers LLP for the audit of X4’s annual financial statements, the review of interim financial statements, and related services that are normally provided in connection with registration statements. Included in 2018 Audit Fees are fees of $542,232 incurred through December 31, 2018 in connection with SEC and other regulatory filings related to the Merger.

(2)

“Audit-Related Fees” consist of fees billed by an independent registered public accounting firm for assurance and related services that are reasonably related to the performance of the audit or review of X4’s financial statements and which are not reported under “Audit Fees.” There were no such fees incurred in 2018 or 2017.

(3)

“Tax Fees” consist of fees primarily related to tax compliance and consulting.

(4)

“All Other Fees” relate to fees for access to the PricewaterhouseCoopers LLP online accounting research and financial disclosure tools.

Policy on Audit CommitteePre-Approval of Audit and PermissibleNon-Audit Services of Independent Public Accountant

Consistent with SEC policies regarding auditor independence, the audit committee has responsibility for appointing, setting compensation for and overseeing the work of our independent registered public accounting firm. In recognition of this responsibility, the audit committee has established a policy topre-approve all audit and permissiblenon-audit services provided by our independent registered public accounting firm.

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 to the audit committee for approval.

1.    Auditservices include audit work performed in the preparation of financial statements, as well as work that generally only an independent registered public accounting firm can reasonably be expected to provide, including comfort letters, statutory audits, consents in connection with registration statements, and attest services and consultation regarding financial accounting and/or reporting standards.

2.    Audit-Related services are for assurance and related services that are traditionally performed by an independent registered public accounting firm, including due diligence related to mergers and acquisitions, employee benefit plan audits, and special procedures required to meet certain regulatory requirements.

3.    Tax services include all services performed by an independent registered public accounting firm’s tax personnel, except those services specifically related to the audit of the financial statements, and include fees in the areas of tax compliance, tax planning and tax advice.

4.    Other Fees are those associated with services not captured in the other categories. We generally do notwithout charge upon written request such services from our independent registered public accounting firm.

Prior to engagement, the audit committeepre-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 the 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 originalpre-approval. In those instances, the audit committee requires specificpre-approval before engaging our independent registered public accounting firm.

The audit committee may delegatepre-approval authority to one or more of its members. The member to whom such authority is delegated must report, for informational purposes only, anypre-approval decisions to the audit committee at its next scheduled meeting.

In the event the stockholders do not ratify the appointment of PricewaterhouseCoopers LLP as our independent registered public accounting firm, the audit committee will reconsider its appointment.

The affirmative vote of the holders of shares of our common stock having a majority in voting power of the votes cast by the holders of all of the shares of our common stock present or represented at the annual meeting and voting affirmatively or negatively on the matter is required to ratify the appointment of our independent registered public accounting firm.

OUR BOARD OF DIRECTORS RECOMMENDS A VOTE TO RATIFY THE APPOINTMENT OF PRICEWATERHOUSECOOPERS LLP AS OUR INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM, AND PROXIES SOLICITED BY OUR BOARD OF DIRECTORS WILL BE VOTED IN FAVOR OF SUCH RATIFICATION UNLESS A STOCKHOLDER INDICATES OTHERWISE ON THE PROXY.

CODE OF BUSINESS CONDUCT AND ETHICS

We have adopted a code of business conduct and ethics that applies to all of our employees, including our chief executive officer and chief financial and accounting officer. We have posted a copy of the code of business conduct and ethics on our website at www.x4pharma.com. Disclosure regarding any amendments to, or waivers from, provisions of the code of business conduct and ethics that apply to our directors, principal executive officer or principal financial officer will be included in a Current Report on Form8-K within four business days following the date of the amendment or waiver, unless website posting or the issuance of a press release of such amendments or waivers is then permitted by the rules of the Nasdaq Stock Market.

OTHER MATTERS

Our board of directors knows of no other business which will be presented to the annual meeting. If any other business is properly brought before the annual meeting, proxies will be voted in accordance with the judgment of the persons named therein.

STOCKHOLDER PROPOSALS AND NOMINATIONS FOR DIRECTOR

To be considered for inclusion in the proxy statement relating to our 2020 annual meeting of stockholders, we must receive stockholder proposals (other than for director nominations) no later than January 24, 2020. To be considered for presentation at the2020 annual meeting of stockholders, although not included in the proxy statement, proposals (including director nominations that are not requested to be included in our proxy statement) must be received no earlier than February 18, 2020 and no later than March 19, 2020. Proposals that are not received in a timely manner will not be voted on at the 2020 annual meeting of stockholders. If a proposal is received on time, the proxies that management solicits for the meeting may still exercise discretionary voting authority on the proposal under circumstances consistent with the proxy rules of the SEC. All stockholder proposals should be marked for the attention ofto: Corporate Secretary, X4 Pharmaceuticals, Inc., 955 Massachusetts Avenue,61 North Beacon Street, 4th Floor, Cambridge, Massachusetts 02139.

Cambridge, Massachusetts

May 22, 2019

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Using a black ink pen, mark your votes with an X as shown in  this example. Please do not write outside the designated areas.

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Your vote matters – here’s how to vote!

You may vote online or by phone instead of mailing this card.

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Votes submitted electronically must be received by 11:59 p.m. EDT on Sunday, June 16, 2019.
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Online

Go towww.investorvote.com/XFOR or scan the QR code – login details are located in the shaded bar below.

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Phone

Call toll free 1-800-652-VOTE (8683) within the USA, US territories and Canada

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Sign up for electronic delivery at www.investorvote.com/XFOR

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q IF VOTING BY MAIL, SIGN, DETACH AND RETURN THE BOTTOM PORTION IN THE ENCLOSED ENVELOPE.q

- - - - - - - - - - - - - - - - - - -  - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  - - - - - - - - - - - - - - - -

 A   Proposals – The Board of Directors recommend a voteFOR the nominee listed andFOR Proposal 2.

1. Election of Directors:

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ForWithhold

      01 - René Russo

For

Against

Abstain

2. Ratify the appointment of PricewaterhouseCoopers LLP as the Company’s independent registered public accounting firm for the fiscal year ending December 31, 2019.

 B   Authorized Signatures – This section must be completed for your vote to count. Please date and sign below.

Please sign exactly as name(s) appears hereon. Joint owners should each sign. When signing as attorney, executor, administrator, corporate officer, trustee, guardian, or custodian, please give full title.

Date (mm/dd/yyyy) – Please print date below.

Signature 1 – Please keep signature within the box.Signature 2 – Please keep signature within the box.

//

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032C6B


2019 Annual Meeting Admission Ticket

2019 Annual Meeting of X4 Pharmaceuticals, Inc. Shareholders

Monday June 17, 2019, 10:00 a.m. EDT

Offices of Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C.,

One Financial Center, Boston, MA 02111

Upon arrival, please present this admission ticket and photo identification at the registration desk.

Important notice regarding the Internet availability of proxy materials for the Annual Meeting of Shareholders.

The material is available at: www.investorvote.com/XFOR

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Small steps make an impact.

Help the environment by consenting to receive electronic

delivery, sign up at www.investorvote.com/XFOR

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02134.

34

q
IF VOTING BY MAIL, SIGN, DETACH AND RETURN THE BOTTOM PORTION IN THE ENCLOSED ENVELOPE.
proxycard11.jpg
q

- - - - - - - - - - - - - - - - - - -  - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -  - - - - - - - - - - - - - - - -

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Notice of 2019 Annual Meeting of Stockholders

Proxy Solicited by Board of Directors for Annual Meeting – June 17, 2019

Paula Ragan. Ph.D. and Adam S. Mostafa, or any of them, each with the power of substitution, are hereby authorized to represent and vote the shares of the undersigned, with all the powers which the undersigned would possess if personally present, at the Annual Meeting of Stockholders of X4 Pharmaceuticals, Inc. to be held on June 17, 2019 or at any postponement or adjournment thereof.

Shares represented by this proxy will be voted by the stockholder. If no such directions are indicated, the Proxies will have authority to vote FOR the election of the Board of Directors and FOR item 2.

In their discretion, the Proxies are authorized to vote upon such other business as may properly come before the meeting.

(Items to be voted appear on reverse side)

 C   Non-Voting Items

Change of Address – Please print new address below.

Comments – Please print your comments below.

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