PRE 14A

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934

(Amendment No. )

Filed by the Registrant ☒

Filed by a Party other than the Registrant ☐

Check the appropriate box:

☒ Preliminary Proxy Statement

☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

☐ Definitive Proxy Statement

☐ Definitive Additional Materials

☐ Soliciting Material under §240.14a-12

SOLID BIOSCIENCES INC.

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Payment of Filing Fee (Check all boxes that apply):

☒ No fee required

☐ Fee paid previously with preliminary materials

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

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PRELIMINARY PROXY STATEMENT—SUBJECT TO COMPLETION, DATED APRIL 10, 2026

500 Rutherford Avenue, 3rd Floor

Charlestown, Massachusetts 02129

NOTICE OF 2026 ANNUAL MEETING OF STOCKHOLDERS

To be held on June 10, 2026

Dear Stockholders,

You are cordially invited to attend the 2026 annual meeting of stockholders (the “Annual Meeting”) of Solid Biosciences Inc., which will be held on Wednesday, June 10, 2026 at 8:00 a.m., Eastern Time. The Annual Meeting will be held in a virtual-only format, solely by means of remote communication, to consider and vote upon the following proposals:

The election of three Class II Directors, Clare Kahn, Adam Stone and Lynne Sullivan, to our Board of Directors (the “Board of Directors” or the “Board”), each to serve until the 2029 annual meeting of stockholders and until the election and qualification of his or her successor;

The ratification of the appointment of Ilan Ganot, on an advisory basis, to our Board of Directors as a Class I Director, to hold office until the 2028 annual meeting of stockholders;

The ratification of the appointment of PricewaterhouseCoopers LLP as our independent registered public accounting firm for the fiscal year ending December 31, 2026;

The approval of an amendment to our Certificate of Incorporation, as amended, to increase the number of authorized shares of our common stock from 240,000,0000 to 480,000,000;

The approval of an advisory vote on executive compensation; and

The transaction of any other business properly brought before the Annual Meeting or any adjournment or postponement of the Annual Meeting.

Stockholders will be able to attend the Annual Meeting only via the webcast and will not be able to attend the Annual Meeting in person. We believe that hosting a “virtual meeting” will enable greater stockholder attendance and participation from any location around the world. We have designed the format of the Annual Meeting to provide stockholders the same rights and opportunities to participate as they would at an in-person meeting.

Our Board has fixed the close of business on April 16, 2026 as the record date (the “Record Date”) for the purpose of determining the stockholders who are entitled to receive notice of, and to vote at, the Annual Meeting. Only stockholders of record at the close of business on the Record Date are entitled to notice of, and to vote at, the Annual Meeting and at any adjournment of that meeting. Stockholders of record at the close of business on the Record Date can attend the Annual Meeting, including to vote their shares and ask questions, by accessing http://www.virtualshareholdermeeting.com/SLDB2026 shortly prior to the scheduled start of the meeting and entering the 16-digit control number included on your proxy card, voting instruction form or notice of availability of proxy materials.

The rules and procedures applicable to the Annual Meeting will be available for the participating stockholders of record at http://www.virtualshareholdermeeting.com/SLDB2026.

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We are pleased to take advantage of Securities and Exchange Commission (“SEC”) rules that allow companies to furnish their proxy materials over the Internet. On or about April [●], 2026, we are mailing to our stockholders a Notice of Internet Availability of Proxy Materials (the “Notice”) instead of a paper copy of our proxy materials and our 2025 Annual Report to Stockholders, which includes our Annual Report on Form 10-K for the fiscal year ended December 31, 2025. The Notice contains instructions on how to access those documents and to cast your vote via the Internet or by telephone. The Notice also contains instructions on how to request a paper copy of our proxy materials and our 2025 Annual Report to Stockholders. All stockholders who do not receive a Notice will receive a paper copy of the proxy materials and the 2025 Annual Report to Stockholders by mail. This process allows us to provide our stockholders with the information they need on a timelier basis, while reducing the environmental impact and lowering the costs of printing and distributing our proxy materials.

Your vote is very important. Whether or not you plan to attend the Annual Meeting online, please vote your shares by proxy as promptly as possible to ensure your representation and the presence of a quorum at the Annual Meeting. You may vote electronically at the meeting, by telephone, online, or by completing and returning a proxy card. We recommend you vote by proxy in advance of the meeting even if you plan to participate in the virtual meeting. You can always change your vote by voting electronically at the virtual meeting.

BY ORDER OF THE BOARD OF DIRECTORS

/s/ Alexander Cumbo

Alexander Cumbo

President and Chief Executive Officer

IMPORTANT NOTICE REGARDING THE INTERNET AVAILABILITY OF PROXY MATERIALS FOR THE ANNUAL STOCKHOLDERS MEETING TO BE HELD ON JUNE 10, 2026:

This proxy statement, the accompanying proxy card or voting instruction form and our 2025 Annual Report to Stockholders, which includes our Annual Report on Form 10-K for the fiscal year ended December 31, 2025, are available for viewing, printing and downloading at: http://materials.proxyvote.com/83422E. These documents are also available to any stockholder who wishes to receive a paper copy by calling 1-800-579-1639 or emailing sendmaterial@proxyvote.com. The proxy statement and our Annual Report on Form 10-K for the fiscal year ended December 31, 2025 are also available on the SEC’s website at http://www.sec.gov.

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Solid Biosciences Inc.

Proxy Statement

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	Page No.
INFORMATION CONCERNING SOLICITATION AND VOTING	1
QUESTIONS AND ANSWERS ABOUT THE ANNUAL MEETING AND PROPOSALS	2
PROPOSAL NO. 1—ELECTION OF CLASS II DIRECTORS	7
PROPOSAL NO. 2 – RATIFICATION OF THE APPOINTMENT OF ILAN GANOT, ON AN ADVISORY BASIS, TO OUR BOARD OF DIRECTORS AS A CLASS I DIRECTOR, TO HOLD OFFICE UNTIL THE 2028 ANNUAL MEETING OF STOCKHOLDERS	11
CORPORATE GOVERNANCE	12
EXECUTIVE OFFICERS	22
EXECUTIVE COMPENSATION	24
PRINCIPAL STOCKHOLDERS	37
CERTAIN RELATIONSHIPS AND RELATED PERSON TRANSACTIONS	40
DELINQUENT SECTION 16(a) REPORTS	43
PROPOSAL NO. 3—RATIFICATION OF THE APPOINTMENT OF PRICEWATERHOUSECOOPERS LLP AS THE COMPANY’S INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM FOR THE FISCAL YEAR ENDING DECEMBER 31, 2026	44
PROPOSAL NO. 4—APPROVAL OF AN AMENDMENT TO OUR CERTIFICATE OF INCORPORATION, AS AMENDED, TO INCREASE THE NUMBER OF AUTHORIZED SHARES OF OUR COMMON STOCK FROM 240,000,000 TO 480,000,000	45
PROPOSAL NO. 5—ADVISORY VOTE ON EXECUTIVE COMPENSATION	47
HOUSEHOLDING	48
STOCKHOLDER PROPOSALS	49
OTHER MATTERS	50
APPENDIX A—AMENDMENT TO CERTIFICATE OF INCORPORATION	A-1

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INFORMATION CONCERNING SOLICITATION AND VOTING

This proxy statement contains information about the Annual Meeting of Stockholders (the “Annual Meeting”) of Solid Biosciences Inc. (the “Company”) to be held on Wednesday, June 10, 2026 at 8:00 a.m., Eastern Time.

Our Board of Directors (the “Board of Directors” or the “Board”) has made this proxy statement and related materials available to you on the Internet, or at your request has delivered printed versions to you by mail, in connection with the solicitation of proxies by the Board of Directors for the Annual Meeting, and any adjournment or postponement of the Annual Meeting. If you requested printed versions of these materials by mail, they will also include a proxy card for the Annual Meeting.

Pursuant to rules adopted by the Securities and Exchange Commission (the “SEC”), we are providing access to our proxy materials over the Internet. Accordingly, we are sending a Notice of Internet Availability of Proxy Materials (the “Notice”) to our stockholders of record and beneficial owners as of April 16, 2026. The mailing of the Notice to our stockholders is scheduled to begin on or about April [●], 2026.

All properly submitted proxies will be voted in accordance with the instructions contained in those proxies. If no instructions are specified, the shares represented by the proxies will be voted in accordance with the recommendation of our Board with respect to each of the matters set forth in the Notice.

IMPORTANT NOTICE REGARDING THE INTERNET AVAILABILITY OF PROXY MATERIALS FOR THE ANNUAL STOCKHOLDERS MEETING TO BE HELD ON JUNE 10, 2026:

This proxy statement, the accompanying proxy card or voting instruction form and our 2025 Annual Report to Stockholders are available at: http://materials.proxyvote.com/83422E.

You may obtain a copy of our Annual Report on Form 10-K for the year ended December 31, 2025, as filed with the SEC, except for exhibits thereto, without charge upon written request to Solid Biosciences Inc., 500 Rutherford Avenue, 3rd Floor, Charlestown, Massachusetts 02129, Attention: Investor Relations. Exhibits will be provided upon written request and payment of an appropriate processing fee.

In this proxy statement, the terms “we,” “us,” “our,” and “the Company” refer to Solid Biosciences Inc. unless the context indicates otherwise.

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QUESTIONS AND ANSWERS ABOUT THE ANNUAL MEETING AND PROPOSALS

The following are some questions that you, as a holder of common stock of the Company, may have regarding the Annual Meeting and the proposals and brief answers to such questions. We urge you to carefully read this entire proxy statement and the documents referred to in this proxy statement because the information in this section does not provide all the information that may be important to you as a stockholder of the Company with respect to the proposals.

When and where will the Annual Meeting take place?

The Annual Meeting will be held on Wednesday, June 10, 2026 at 8:00 a.m., Eastern Time. The Annual Meeting will be held via the Internet at a webcast at http://www.virtualshareholdermeeting.com/SLDB2026. As always, we encourage you to vote your shares prior to the Annual Meeting regardless of whether you intend to attend virtually via the webcast.

What proposals are the stockholders being asked to consider?

At the Annual Meeting, you will be asked to vote upon:

The election of three Class II Directors, Clare Kahn, Adam Stone and Lynne Sullivan (the “Director Nominees”), to our Board of Directors, each to serve until the 2029 annual meeting of stockholders and until the election and qualification of his or her successor (“Proposal No. 1”);

The ratification of the appointment of Ilan Ganot, on an advisory basis, to our Board of Directors as a Class I Director, to hold office until the 2028 annual meeting of stockholders (“Proposal No. 2”);

The ratification of the appointment of PricewaterhouseCoopers LLP as our independent registered public accounting firm for the fiscal year ending December 31, 2026 (“Proposal No. 3”);

The approval of an amendment to our Certificate of Incorporation, as amended (the “Certificate of Incorporation”), to increase the number of authorized shares of our common stock from 240,000,000 to 480,000,000 (“Proposal No. 4”);

The approval of an advisory vote on executive compensation (“Proposal No. 5”); and

The transaction of any other business properly brought before the Annual Meeting or any adjournment or postponement of the Annual Meeting.

What are the recommendations of the Board?

The Board unanimously recommends that the stockholders vote:

“FOR” the election of each of the Director Nominees;

“FOR” the ratification of the appointment of Ilan Ganot, on an advisory basis, to our Board of Directors as a Class I Director, to hold office until the 2028 annual meeting of stockholders;

“FOR” the ratification of the appointment of PricewaterhouseCoopers LLP as our independent registered public accounting firm for the fiscal year ending December 31, 2026;

“FOR” the approval of an amendment to our Certificate of Incorporation to increase the number of authorized shares of our common stock from 240,000,000 to 480,000,000; and

“FOR” the approval of the advisory vote on executive compensation.

Are there other matters to be voted on at the Annual Meeting?

We do not know of any matters that may come before the Annual Meeting other than Proposals No. 1, 2, 3, 4 and 5. If any other matters are properly presented at the Annual Meeting, the persons named in the accompanying proxy card intend to vote, or otherwise act, in accordance with their best judgment on the matter.

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What is the Record Date for the Annual Meeting?

Holders of our common stock as of the close of business on April 16, 2026 (the “Record Date”) are entitled to notice of, and to vote at, the Annual Meeting.

Who can vote at the Annual Meeting?

Stockholders who owned shares of our common stock on the Record Date may attend and vote at the Annual Meeting. There were [●] shares of our common stock outstanding on the Record Date. All shares of common stock have one vote per share and vote together as a single class.

What is the proxy card?

The proxy card enables you to appoint Alexander Cumbo, Kevin Tan and David Tyronne Howton as your proxies at the Annual Meeting. By completing and returning or submitting the proxy card as described herein or in the Notice, you are authorizing these individuals to vote your shares at the Annual Meeting in accordance with your instructions on the proxy card. This way, your shares will be voted whether or not you attend the Annual Meeting. Even if you plan to attend the Annual Meeting online, we recommend completing and returning or submitting your proxy card before the Annual Meeting date in the event your plans change. If a proposal comes up for vote at the Annual Meeting that is not on the proxy card, the proxies will vote your shares, under your proxy, according to their best judgment.

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

Most of our stockholders hold their shares through a bank, broker or other nominee, rather than holding their shares in their own name. As summarized below, there are some distinctions between shares held of record and those beneficially owned.

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Stockholders of Record. If your shares are held in your own name, you are a stockholder of record. If you are a stockholder of record and do not vote over the Internet, by phone or by mailing your proxy card, your shares will not be voted unless you attend the Annual Meeting and vote your shares electronically at the Annual Meeting. If you are a stockholder of record and you submit a proxy card without giving specific voting instructions on one or more matters listed in the Notice, your shares will be voted as recommended by our Board on such matters, and as the proxyholders may determine in their discretion with respect to any other matters properly presented for a vote at the Annual Meeting.

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Beneficial Owners of Shares Held in Street Name. If your shares are held through a bank, broker or other nominee, you are considered the beneficial owner of shares held in “street name.” If you are a beneficial owner of shares held in street name and do not vote over the Internet, by phone or by mailing your proxy card, under the rules of various securities exchanges, the bank, broker or other nominee that holds your shares may generally vote your shares on “discretionary” matters in the absence of voting instructions from you, but they cannot vote your shares on “non-discretionary” matters. Of the matters to be voted on at the Annual Meeting, we expect the only proposals on which banks, brokers and other nominees will have discretionary voting authority are the ratification of the appointment of PricewaterhouseCoopers LLP as our independent registered public accounting firm for the fiscal year ending December 31, 2026 (Proposal No. 3) and the approval of an amendment to our Certificate of Incorporation to increase the number of authorized shares of our common stock from 240,000,000 to 480,000,000 (Proposal No. 4). The election of our Director Nominees (Proposal No. 1), the advisory vote on the ratification of the appointment of a Class I Director (Proposal No. 2), and the advisory vote on executive compensation (Proposal No. 5) are considered “non-discretionary” matters.

A “broker non-vote” results on a matter when your bank, broker or other nominee returns a proxy but does not vote on a particular proposal because it does not have discretionary authority to vote on that proposal and has not received voting instructions from you.

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How do I virtually attend the Annual Meeting?

We will host the Annual Meeting live online via webcast. You may attend the Annual Meeting live online by visiting http://www.virtualshareholdermeeting.com/SLDB2026. The live audio webcast will start at 8:00 a.m. Eastern time on Wednesday, June 10, 2026. Online access to the audio webcast will open 10 minutes prior to the start of the Annual Meeting to allow time for you to log-in and test your device’s audio system. To be admitted to the virtual Annual Meeting, you will need to log-in at http://www.virtualshareholdermeeting.com/SLDB2026 using the 16-digit control number included on your proxy card, voting instruction form or Notice. You are entitled to participate in the Annual Meeting only if you were a stockholder as of the close of business on the Record Date, or if you hold a valid proxy for the Annual Meeting.

Beginning 10 minutes prior to, and during, the Annual Meeting, we will have support available to assist stockholders with any technical difficulties in accessing or hearing the virtual meeting. If you encounter any difficulty accessing the Annual Meeting or during the Annual Meeting, please call the support team at the numbers listed on the web portal at the time of the Annual Meeting.

How do I submit a question at the Annual Meeting?

You will be able to submit your questions prior to and during the Annual Meeting by visiting http://www.virtualshareholdermeeting.com/SLDB2026. Our Annual Meeting will be governed by our Rules of Conduct and Procedures, which will be posted at http://www.virtualshareholdermeeting.com/SLDB2026 during the Annual Meeting. The Rules of Conduct and Procedures will address the ability of stockholders to ask questions during the meeting, including rules on permissible topics and rules for how questions and comments will be recognized. We will answer appropriate questions that are pertinent to the Company and the matters to be voted on by the stockholders at the Annual Meeting. Because time is limited at the Annual Meeting, we may not be able to answer all questions that are submitted. To promote fairness, efficiently use the Company’s resources and better address all stockholder questions, we will limit each stockholder to one question, which should be succinct and should cover only one topic. Questions from multiple stockholders on the same topic or that are otherwise related may be grouped, summarized and answered together.

May I see a list of stockholders entitled to vote as of the Record Date?

A complete list of stockholders entitled to vote at the Annual Meeting will be available for examination by any stockholder for any purpose germane to the meeting for a period of 10 days ending on the day before June 10, 2026. If you wish to view this list, please contact our secretary at Solid Biosciences Inc., 500 Rutherford Avenue, 3rd Floor, Charlestown, Massachusetts 02129 or (617) 337-4680.

How do I vote?

Stockholders have four voting options. You may vote using any of the following methods:

Internet. To vote on the Internet, please go to the following website: www.proxyvote.com and follow the instructions at that site for submitting your proxy electronically.

Telephone. To vote by telephone, please call 1-800-690-6903 and follow the instructions provided on the proxy card.

Mail. If you requested or received a paper proxy card and voting instructions by mail, simply complete, sign and date the enclosed proxy card and return it before the Annual Meeting in the envelope provided.

Online during the Annual Meeting. You may vote your shares online while virtually attending the Annual Meeting by visiting http://www.virtualshareholdermeeting.com/SLDB2026. You will need your 16-digit control number included on your proxy card in order to be able to vote during the Annual Meeting. Even if you plan to attend the Annual Meeting online, we urge you to vote your shares by proxy in advance of the Annual Meeting so that if you should become unable to attend the Annual Meeting online your shares will be voted as directed by you.

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Telephone and Internet voting for stockholders of record will be available up until 11:59 p.m., Eastern Time, on June 9, 2026, and mailed proxy cards must be received by June 9, 2026 in order to be counted at the Annual Meeting. If the Annual Meeting is adjourned or postponed, these deadlines may be extended.

What is the quorum required for the Annual Meeting?

The representation online or by proxy of holders of at least a majority of the issued and outstanding shares of our common stock entitled to vote at the Annual Meeting is necessary to constitute a quorum for the transaction of business at the Annual Meeting. Shares present virtually during the Annual Meeting will be considered shares of common stock represented online at the meeting. For purposes of determining the presence of a quorum, abstentions and broker non-votes will be counted as present at the Annual Meeting. If a quorum is not present, we expect to adjourn the Annual Meeting until a quorum is obtained.

Assuming that a quorum is present, what vote is required to approve the proposals to be voted upon at the Annual Meeting and how are votes counted?

Proposal No. 1. The election of each Director Nominee requires the affirmative vote of a plurality of votes cast “FOR” the applicable seat on the Board of Directors. The three Director Nominees to receive the highest number of votes FOR election will be elected as Class II directors. Proposal No. 1 is considered a non-discretionary matter. If your shares are held in “street name” and you do not instruct your bank, broker or other nominee how to vote with respect to Proposal No. 1, your bank, broker or other nominee may not vote with respect to Proposal No. 1 and your shares will be counted as “broker non-votes.” Votes withheld and broker non-votes will not be counted as votes cast or voted on Proposal No. 1. Accordingly, votes withheld and broker non-votes will have no effect on the voting on Proposal No. 1.

Proposal No. 2. The ratification of the appointment of Ilan Ganot as a Class I Director, on an advisory basis, requires the affirmative vote of a majority of the shares present online or represented by proxy at the Annual Meeting. Proposal No. 2 is considered a non-discretionary matter. If your shares are held in “street name” and you do not instruct your bank, broker or other nominee how to vote with respect to Proposal No. 2, your bank, broker or other nominee may not vote with respect to Proposal No. 2 and your shares will be counted as “broker non-votes.” Broker non-votes will have the same effect as a vote AGAINST this proposal. If you vote to ABSTAIN on Proposal No. 2, your shares will not be voted FOR or AGAINST the proposal, which has the same effect as a vote AGAINST the proposal.

Proposal No. 3. The ratification of the appointment of PricewaterhouseCoopers LLP requires the affirmative vote of a majority of the shares present online or represented by proxy at the Annual Meeting. If your shares are held in “street name,” we expect that your bank, broker or other nominee will be able to exercise discretionary authority to vote on this matter in the absence of voting instructions from you. If your bank, broker or other nominee exercises this discretionary authority, no broker non-votes are expected to occur in connection with Proposal No. 3. To the extent there are any broker non-votes, a broker non-vote will have the same effect as a vote AGAINST the proposal. If you vote to ABSTAIN on Proposal No. 3, your shares will not be voted FOR or AGAINST the proposal, which has the same effect as a vote AGAINST the proposal.

Proposal No. 4. The approval of an amendment to our Certificate of Incorporation to increase the number of authorized shares of our common stock from 240,000,000 to 480,000,000 requires the affirmative vote of a majority of the votes cast by the stockholders entitled to vote thereon at the Annual Meeting. If your shares are held in “street name,” we expect that your bank, broker or other nominee will be able to exercise discretionary authority to vote on this matter in the absence of voting instructions from you. If your bank, broker or other nominee exercises this discretionary authority, no broker non-votes are expected to occur in connection with Proposal No. 4. To the extent there are any broker non-votes, a broker non-vote will have no effect on the voting on the proposal. If you vote to ABSTAIN on Proposal No. 4, your shares will not be voted FOR or AGAINST the proposal and will also not be counted as votes cast or shares voting on the proposal. As a result, a vote to ABSTAIN will have no effect on the voting on Proposal No. 4.

Proposal No. 5. The approval of the advisory vote on executive compensation requires the affirmative vote of a majority of the shares present online or represented by proxy at the Annual Meeting. Proposal No. 5 is considered a non-discretionary matter. If your shares are held in “street name” and you do not instruct your bank, broker or other nominee how to vote with respect to Proposal No. 5, your bank, broker or other nominee may not vote with respect to Proposal No. 5 and your shares will be counted as “broker non-votes.” Broker non-votes will have the

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same effect as a vote AGAINST this proposal. If you vote to ABSTAIN on Proposal No. 5, your shares will not be voted FOR or AGAINST the proposal, which has the same effect as a vote AGAINST the proposal. As described in more detail in Proposal No. 5, because Proposal No. 5 is non-binding, our Board of Directors may decide that it is in our and our stockholders’ best interests to compensate our named executive officers in an amount or manner that differs from that which is approved by our stockholders.

What does it mean if I received more than one proxy card or Notice?

If your shares are registered differently or in more than one account, you will receive more than one proxy card or Notice. To make certain all of your shares are voted, please follow the instructions included on the Notice on how to access each proxy card and vote each proxy card by telephone or through the Internet. If you requested or received paper proxy materials by mail, please complete, sign and return each proxy card to ensure that all of your shares are voted.

What happens if I don’t indicate how to vote my proxy?

If you just sign or submit your proxy card without providing further instructions, your shares will be counted as a vote “FOR” the election of each of the Director Nominees and as a vote “FOR” each of Proposals No. 2, 3, 4 and 5.

What if I change my mind after I return my proxy?

You may revoke your proxy and change your vote at any time before the polls close at the Annual Meeting. You may do this by:

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sending us a written notice to 500 Rutherford Avenue, 3rd Floor, Charlestown, Massachusetts 02129, Attention: Secretary stating that you would like to revoke your proxy of a particular date;

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voting again at a later time, but prior to the date of the Annual Meeting, via the Internet or telephone;

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signing or submitting another proxy card with a later date and returning it prior to the Annual Meeting; or

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attending the Annual Meeting online and voting during the Annual Meeting. Attending the Annual Meeting online will not alone revoke your Internet vote, telephone vote or proxy card submitted by mail, as the case may be.

Please note, however, that if your shares are held in street name by a bank, broker or other nominee, you must instruct your bank, broker or other nominee that you wish to change your vote by following the procedures on the voting form provided to you by the bank, broker or other nominee. If your shares are held in street name, and you wish to attend and vote at the Annual Meeting, you will need your 16-digit control number included on your proxy card or voting instruction form in order to demonstrate proof of beneficial ownership and to be able to vote during the Annual Meeting. Instructions on how to attend and participate online, including how to demonstrate proof of stock ownership, are posted at http://www.virtualshareholdermeeting.com/SLDB2026. Simply attending the Annual Meeting will not alone constitute a revocation of your proxy.

Who will bear the costs of the proxy solicitation?

We will bear the costs of soliciting proxies. In addition to solicitations by mail, our directors, officers and regular employees, without additional remuneration, may solicit proxies by telephone, facsimile, email, personal interviews and other means. In addition, we may also retain a proxy solicitation firm to solicit proxies in connection with the Annual Meeting at an anticipated cost of approximately $17,500, plus reimbursement of certain expenses and fees for additional services requested. If retained, proxies may be solicited by the proxy solicitation firm by mail, telephone, email and in person.

When will the voting results be announced?

We plan to announce preliminary voting results at the Annual Meeting and will publish final results in a Current Report on Form 8-K to be filed with the SEC within four business days following the Annual Meeting.

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PROPOSAL NO. 1—ELECTION OF CLASS II DIRECTORS

Our Board is divided into three classes, with one class of our directors standing for election each year. Directors in each class are elected at the annual meeting of stockholders held in the year in which the term for their class expires and hold office for a three-year term until the election and qualification of their successors and subject to their earlier death, resignation or removal. In accordance with our Certificate of Incorporation and bylaws, our directors may fill existing vacancies on the Board by appointment. The members of the classes are divided as follows:

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the Class I Directors are Alexander Cumbo, Ilan Ganot and Sukumar Nagendran and their term will expire at the annual meeting of stockholders to be held in 2028;

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the Class II Directors are Clare Kahn, Adam Stone and Lynne Sullivan and their term expires at the Annual Meeting; and

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the Class III Directors are Martin Freed, Georgia Keresty and Ian Smith and their term expires at the annual meeting of stockholders to be held in 2027.

Our Certificate of Incorporation and bylaws provide that the authorized number of directors may be changed only by resolution of our Board. Our Certificate of Incorporation and bylaws also provide that our directors may be removed only for cause by the affirmative vote of the holders of at least two-thirds of the votes that all our stockholders would be entitled to cast in an annual election of directors, and that any vacancy on our Board, including a vacancy resulting from an enlargement of our Board, may be filled only by vote of a majority of our directors then in office.

Our Board, on the recommendation of our nominating and corporate governance committee, has nominated Clare Kahn, Adam Stone and Lynne Sullivan for election as Class II Directors at the Annual Meeting. Dr. Kahn, Mr. Stone and Ms. Sullivan are standing for re-election by the stockholders at this Annual Meeting. Each director that is elected at the Annual Meeting will be elected to serve for a three-year term that will expire at our annual meeting of stockholders to be held in 2029.

If no contrary indication is made, proxies in the accompanying form will be voted “FOR” Clare Kahn, Adam Stone and Lynne Sullivan or, in the event that any of these candidates is not a candidate or is unable to serve as a director at the time of election (which is not currently expected), for any nominee who is designated by our Board to fill the vacancy.

We have no formal policy regarding board diversity, but our corporate governance guidelines provide that the background and qualifications of the members of our Board considered as a group should provide a significant breadth of experience, knowledge, and ability to assist our Board in fulfilling its responsibilities. Our priority in selection of board members is identification of members who will further the interests of our stockholders through their established record of professional accomplishment, the ability to contribute positively to the collaborative culture among board members, knowledge of our business, understanding of the competitive landscape and adherence to high ethical standards. Certain individual skills and qualifications of our directors, which we believe contribute to the effectiveness of the Board as a whole, are described in this proxy statement.

Information Regarding Directors

The information set forth below as to the directors and Director Nominees, which includes their name and age as of April 1, 2026, has been furnished to us by the directors and Director Nominees.

Recommendation of the Board

OUR BOARD UNANIMOUSLY RECOMMENDS THAT THE STOCKHOLDERS VOTE “FOR” THE ELECTION OF EACH OF THE DIRECTOR NOMINEES.

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Nominees for Election to the Board

Term Expiring at the
2029 Annual Meeting of Stockholders, if elected at the Annual Meeting (Class II)


Name	Age	Position(s) Held
Clare Kahn, Ph.D.	74	Director
Adam Stone	46	Director
Lynne Sullivan	60	Director

Clare Kahn, Ph.D. has served as a member of our Board of Directors since March 2021 and has served as a consultant to us since June 2022. Dr. Kahn has served as R&D Strategy Officer at X-VAX Technology Inc. (“X-VAX”), a biotechnology company developing vaccines against pathogens acquired by mucosal infection such as herpes, since September 2019. She served as Chief Regulatory and Preclinical Development Officer at X-VAX from September 2018 to September 2019. Dr. Kahn has also been the president of Clare Kahn Pharma Consulting LLC, through which she provides consulting services on regulatory strategy since July 2016. Dr. Kahn was previously Vice President, Worldwide Regulatory Strategy, Global Innovative Pharma at Pfizer from January 2014 to June 2016 and Vice President, Worldwide Regulatory Strategy, Specialty Care Business at Pfizer from June 2010 to December 2013. Prior to Pfizer, she was Vice President of Regulatory Affairs for a variety of therapeutic areas including cardiovascular, metabolic, urology, oncology and vaccines at GlaxoSmithKline from 1999 to 2010. Dr. Kahn has a Ph.D. in Biochemical Pharmacology from The Royal Postgraduate Medical School, London and served as Assistant Professor of Pharmacology and of Pathology and Laboratory Medicine at The University of Pennsylvania from 1981 to 1985. Dr. Kahn is qualified to serve on our Board of Directors because of her extensive leadership experience and her experience working in the healthcare sector.

Adam Stone has served as a member of our Board of Directors since November 2015. Mr. Stone is currently the Chief Investment Officer of Perceptive Advisors, a life sciences focused investing firm, where he has worked since 2006. Since July 2021 and February 2021, respectively, Mr. Stone has served as a director and Chief Executive Officer Perceptive Capital Solutions Corp. Mr. Stone is currently a member of the Board of Directors of Immatics N.V., a public biopharmaceutical company, and LianBio and Xontogency LLC, both private companies, and he previously served as a member of the Board of Directors of Renovia Inc. and Prometheus Biosciences, Inc. Mr. Stone received a B.A. in molecular biology from Princeton University. Mr. Stone is qualified to serve on our Board of Directors because of his extensive experience developing early-stage biotech and healthcare companies.

Lynne Sullivan has served as a member of our Board of Directors since November 2015. Ms. Sullivan served as the Chief Financial Officer for UNITY Biotechnology, Inc., a biotechnology company, from August 2020 to July 2025. Prior to that, Ms. Sullivan served as the Chief Financial Officer for Compass Therapeutics, LLC (“Compass”), a biotechnology company, from December 2018 to August 2019. Prior to Compass, Ms. Sullivan served as Biogen Inc.’s senior vice president of Finance from 2016 to December 2018, where she also served as vice president of Tax and Corporate Finance from February 2015 to March 2016 and vice president of Tax from April 2008 to February 2015. Ms. Sullivan previously served as a member of the Board of Directors of Inozyme Pharma, Inc., a public biopharmaceutical company, and BiomX Inc. She received an M.S. in Taxation from Bentley University and a B.S.B.A. from Suffolk University. Ms. Sullivan was a Certified Public Accountant for over 20 years. Ms. Sullivan is qualified to serve on our Board of Directors because of her extensive experience in public accounting and financial expertise and her experience working in the healthcare sector.

Members of the Board Continuing in Office

Term Expiring at the

2028 Annual Meeting of Stockholders (Class I)


Name	Age	Position(s) Held
Alexander Cumbo	55	President, Chief Executive Officer and Director
Ilan Ganot	52	Co-Founder and Director
Sukumar Nagendran, M.D.	60	Director

Alexander Cumbo has served as our President and Chief Executive Officer and as a director since December 2022. Prior to that, Mr. Cumbo served as the President and Chief Executive Officer and as a director of AavantiBio, Inc. (“AavantiBio”), a

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gene therapy company, from October 2020 to December 2022, when we acquired AavantiBio. From January 2013 to October 2020, Mr. Cumbo held positions of increasing responsibility at Sarepta Therapeutics, Inc. (“Sarepta”), a precision genetic medicine company, ultimately serving as Executive Vice President, Chief Commercial Officer. From 2011 to 2013, Mr. Cumbo served as Vice President of Sales and Treatment Education for Vertex Pharmaceuticals Incorporated , a biotechnology company (“Vertex”), launching Incivek, a treatment for hepatitis C, and from 2010 to 2011, he served as area director for Vertex. Prior to Vertex, Mr. Cumbo served in multiple commercial roles supporting the HIV, HBV and cardiovascular franchises at Gilead Sciences, Inc., a biopharmaceutical company. Mr. Cumbo has served on the Board of Directors of Climb Bio, Inc. since March 2025, and the Board of Directors of Vor Biopharma Inc. since July 2025. Mr. Cumbo previously served on the Board of Directors of RA Pharmaceuticals, Inc., a clinical stage biopharmaceutical company acquired by UCB, Brussels, from November 2018 to April 2020 and Verve Therapeutics Inc., a biopharmaceutical company acquired by Eli Lilly, from June 2022 to July 2025. Mr. Cumbo received a Bachelor of Science in Laboratory Technology from Auburn University. Mr. Cumbo is qualified to serve on our Board of Directors based on his extensive and broad range of experience in the biopharmaceutical industry and his deep knowledge of our company as our Chief Executive Officer.

Ilan Ganot is one of our founders and has served as a member of our Board of Directors since our inception in 2013. He also served as our Chief Executive Officer from 2013 to December 2022 and as our President from June 2018 to December 2022. From December 2022 to December 2023, Mr. Ganot assisted with the transition of his duties to Mr. Cumbo and provided other consulting and advisory services, as requested from time to time by us. Mr. Ganot is currently the Chief Executive Officer and a member of the Board of Alesta Therapeutics, a biotechnology company focused on the development of innovative therapies for rare diseases. Mr. Ganot is also a member of the Board of Directors of Minovia Therapeutics, a biotechnology company. Previously, Mr. Ganot served as an investment banker at JPMorgan Chase & Co., Nomura Securities Co., Ltd., and Lehman Brothers. Mr. Ganot received his MBA from London Business School and holds law and business degrees from Reichman University in Herzliya, Israel. Mr. Ganot also practiced corporate law in Israel and was a Captain in the Israeli Defense Forces. He is qualified to serve on our Board of Directors because of his personal dedication to improving treatments available for Duchenne patients, his extensive leadership experience and his extensive knowledge of our company based on his previous role as our Chief Executive Officer.

Sukumar Nagendran, M.D. has served as a member of our Board of Directors since September 2018. Since December 2022, Dr. Nagendran has served as President, Head of Research and Development at Taysha Gene Therapies, Inc., a gene therapy company, and he has served as a member of their Board of Directors since July 2020. Prior to that, he was the Chief Medical Officer and President of Research and Development at Jaguar Gene Therapy, a biotechnology company (“Jaguar”), from February 2020 to December 2022. Prior to Jaguar, Dr. Nagendran was Chief Medical Officer and Senior Vice President of AveXis Inc., a clinical-stage gene therapy company (“AveXis”), from September 2015 to July 2018, prior to the company’s acquisition by Novartis Pharmaceuticals Corporation (“Novartis”). Prior to AveXis, Dr. Nagendran was Vice President of Medical Affairs of Quest Diagnostics, a provider of diagnostic information services, from March 2013 to September 2015. Prior to Quest Diagnostics, Dr. Nagendran held key leadership positions at Pfizer Inc. (“Pfizer”), Novartis, Daiichi Sankyo, and Reata Pharmaceuticals. Prior to moving to the biotech industry, Dr. Nagendran practiced internal medicine, with a focus on diabetes and cardiovascular disease. He is a Mayo Alumni Laureate and founding member of the Robert Wood Johnson Legacy Society. He is also the sponsor for the Fonseca-Nagendran Scholar award at the American Diabetes Association to enhance research in minority populations. Dr. Nagendran currently serves on the Board of Directors of SalioGen Therapeutics. Dr. Nagendran received his undergraduate degree in Biochemistry from Rutgers University and his M.D. from Rutgers Medical School and trained in Internal Medicine at Mayo Clinic, Rochester. Dr. Nagendran is qualified to serve on our Board of Directors because of his extensive leadership experience and his experience working in the healthcare sector.

Term Expiring at the

2027 Annual Meeting of Stockholders (Class III)


Name	Age	Position(s) Held
Martin Freed, M.D.	65	Director
Georgia Keresty, Ph.D.	64	Director
Ian F. Smith	60	Executive Chairman of the Board of Directors

Martin Freed, M.D., F.A.C.P. has served as a member of our Board of Directors since June 2018. Dr. Freed has served as an independent consultant to several private pharmaceutical, biotechnology, and healthcare companies, specializing in clinical and general pharmaceutical development and clinical and regulatory strategy since February 2015. He co-founded and served as Chief Medical Officer of Civitas Therapeutics, Inc., a biopharmaceutical company acquired by Acorda Therapeutics, Inc., from

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December 2010 to October 2014, and as Senior Vice President, Clinical Development of Acorda Therapeutics, Inc. from October 2014 to January 2015. He has also served as Chief Medical Officer at Adnexus Therapeutics, Inc. (acquired by Bristol-Myers Squibb) and Vitae Pharmaceuticals, Inc. Dr. Freed spent nearly 14 years at GlaxoSmithKline and its predecessor, SmithKline Beecham Pharmaceuticals or SmithKline Beecham, where he served numerous roles including vice president, clinical development and medical affairs in the metabolism therapeutic area. Dr. Freed currently serves on the Board of Directors for Avilar Therapeutics, Inc. He previously served on the Board of Directors for Sojournix, Inc., Dicerna Pharmaceuticals and Intekrin Therapeutics. Dr. Freed has been Board Certified in Internal Medicine, Nephrology and Clinical Pharmacology. He performed his internal medicine residency at Temple University Hospital and nephrology fellowship at Yale-New Haven Hospital. A Fellow of the American College of Physicians, Dr. Freed received a B.S. with distinction in biology from the University of Delaware and an M.D. from Pennsylvania State University’s College of Medicine. Dr. Freed is qualified to serve on our Board of Directors because of his extensive leadership experience, his public company board experience and his experience working in the healthcare sector.

Georgia Keresty, Ph.D., M.PH. has served as a member of our Board of Directors since March 2021. Dr. Keresty served as the Chief Operating Officer at Volnay Therapeutics, a biotechnology start-up company, from March 2023 to November 2024. Prior to this role, Dr. Keresty served as a senior advisor to Takeda R&D in 2021 and was their R&D Chief Operating Officer from 2017 to 2020. From 2003 to 2017 and from 1997 to 1999, she was an executive at Johnson & Johnson. From 1999 to 2003 and from 1983 to 1997, she held roles at Bristol-Myers Squibb Company and Novartis, respectively. Dr. Keresty holds BSc degrees in Chemical Engineering and Computer Science from Clarkson University and Ramapo College of New Jersey, an M.S. degree in Information Systems from Pace University, an MBA in Operations Management from Rutgers University, a Ph.D. in Operations Management from Rutgers University, and an MPH in Global Health Leadership from the University of Southern California. Dr. Keresty currently serves on the Board of Directors of Intellia Therapeutics, Inc. Dr. Keresty previously served on the Board of Directors of Aspen Technology, Inc. and Commissioning Agents, Inc. Dr. Keresty is also an NACD Board Leadership Fellow and Directorship Certified® since September 2020 and earned an NACD CERT Certificate in Cyber-Risk Oversight in January 2024. Dr. Keresty is qualified to serve on our Board of Directors because of her extensive leadership and governance experience, and her experience working in the healthcare sector.

Ian F. Smith is Executive Chairman of our Board of Directors and has served as a member of our Board of Directors since April 2020 and served as a consultant to us from February 2020 to December 2021. Mr. Smith is also the Chief Executive Officer and a member of the Board of Directors of Stoke Therapeutics, the Chairman of the Board of Directors of Rivus Pharmaceuticals, Inc., and a member of the Board of Directors of Foghorn Therapeutics Inc., Odyssey Therapeutics, Inc. and Alkeus Pharmaceuticals, Inc., which are all biotechnology companies. He is also a Senior Advisor to Bain Capital Life Sciences. Between 2001 and 2019, Mr. Smith served as Chief Financial Officer and then Chief Operating Officer at Vertex. He received a B.A. with honors in accounting and finance from Manchester Metropolitan University (UK). Mr. Smith is qualified to serve on our Board of Directors because of his more than 25 years of finance and broad operating experience for public companies in the biopharmaceutical industry.

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PROPOSAL NO. 2—THE RATIFICATION OF THE APPOINTMENT OF ILAN GANOT, ON AN ADVISORY BASIS, TO OUR BOARD OF DIRECTORS AS A CLASS I DIRECTOR TO HOLD OFFICE UNTIL THE 2028 ANNUAL MEETING OF STOCKHOLDERS

Our Certificate of Incorporation requires that our Board of Directors be divided into three classes, as nearly equal in number as possible. In accordance with our Certificate of Incorporation and bylaws, our directors may fill existing vacancies (including vacancies as a result of a director resignation) on the Board by appointment and without a vote of the stockholders.

In order to ensure that the classes of directors be as nearly equal in number as possible, Ilan Ganot, a then-Class III Director (which class is up for election by our stockholders at the annual meeting of stockholders to be held in 2027), resigned from the Board of Directors effective at 4:00 p.m., Eastern Time, on April 10, 2026 (the “Ganot Resignation”). The Board of Directors, upon the recommendation of the nominating and corporate governance committee, simultaneously with the effectiveness of the Ganot Resignation, appointed Mr. Ganot to the Board of Directors as a Class I Director with a term that expires at the annual meeting of stockholders to be held in 2028. Because Mr. Ganot will move from Class III to Class I and therefore will not stand for re-election by our stockholders at the annual meeting of stockholders to be held in 2027, the nominating and corporate governance committee and the Board of Directors believe that, in keeping with our commitment to good corporate governance practices, it is appropriate for the appointment of Mr. Ganot as a Class I Director to be ratified by the stockholders in an advisory manner at the Annual Meeting. Therefore, the Board of Directors adopted a resolution to have our stockholders vote, on an advisory basis, to ratify the appointment of Mr. Ganot to the Board of Directors as a Class I Director.

This Proposal No. 2 is advisory and therefore is not binding on us or the Board of Directors. However, the Board and the nominating and corporate governance committee value the opinions of the stockholders. As such, if a majority of the shares present online or represented by proxy at the Annual Meeting do not approve the ratification of Mr. Ganot’s appointment to the Board of Directors as a Class I Director, the nominating and corporate governance committee will consider whether to ask Mr. Ganot to resign from the Board of Directors. If the nominating and corporate governance committee requests that Mr. Ganot resign from the Board of Directors, and if Mr. Ganot resigns and the Board of Directors accepts such resignation, Mr. Ganot will no longer be a member of the Board of Directors. In that case, the Board of Directors may appoint a replacement to fill the vacancy or decrease the number of directors to eliminate the vacancy. If the Board of Directors rejects such resignation, we will publicly disclose that decision and the rationale behind it.

Recommendation of the Board

OUR BOARD UNANIMOUSLY RECOMMENDS THAT THE STOCKHOLDERS VOTE “FOR” THE RATIFICATION OF THE APPOINTMENT OF ILAN GANOT, ON AN ADVISORY BASIS, TO THE BOARD OF DIRECTORS AS A CLASS I DIRECTOR TO HOLD OFFICE UNTIL THE 2028 ANNUAL MEETING OF STOCKHOLDERS

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CORPORATE GOVERNANCE

General

We believe that good corporate governance is important to ensure that the Company is managed for the long-term benefit of our stockholders. This section describes key corporate governance practices that we have adopted. We have adopted a code of business conduct and ethics (the “Code of Conduct”), which applies to all of our officers, directors and employees, and corporate governance guidelines and charters for our audit committee, our compensation committee, our nominating and corporate governance committee and our clinical committee. We have posted copies of our Code of Conduct and corporate governance guidelines, as well as each of our committee charters, on the “Governance & Financials” section of the “Investors & Media” page of our website, www.solidbio.com, which you can access free of charge. Information contained on our website is not incorporated by reference in, or considered part of, this proxy statement. We will also provide copies of these documents as well as our other corporate governance documents, free of charge, to any stockholder upon written request to Solid Biosciences Inc., 500 Rutherford Avenue, 3rd Floor, Charlestown, Massachusetts 02129, Attention: Investor Relations.

Corporate Governance Guidelines

Our Board of Directors has adopted corporate governance guidelines to assist in the exercise of its duties and responsibilities and to serve the best interests of the Company and our stockholders. These guidelines, which provide a framework for the conduct of our Board’s business, provide that:

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our Board’s principal responsibility is to oversee the management of the Company;

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except as may be otherwise permitted by Nasdaq listing standards, a majority of the members of our Board shall be independent directors;

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the independent directors meet at least twice annually in executive session;

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directors have full and free access to officers and employees of the Company;

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our Board has the power to hire and consult with independent advisors;

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new directors participate in an orientation program and directors may be expected to participate in continuing director education; and

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our nominating and corporate governance committee will oversee an annual self-evaluation of the Board to determine whether it and its committees are functioning effectively.

A copy of the corporate governance guidelines can be found on the “Governance & Financials” section of the “Investors & Media” page of our website at www.solidbio.com.

Director Independence

Nasdaq rules require a majority of a listed company’s board of directors to be comprised of independent directors. In addition, Nasdaq rules require that, subject to specified exceptions, each member of a listed company’s audit, compensation and nominating and corporate governance committees be independent. Audit committee members must also satisfy independence criteria set forth in Rule 10A-3 under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and compensation committee members must also satisfy the independence criteria set forth in Rule 10C-1 under the Exchange Act. The Nasdaq independence definition includes a series of objective tests, such as that the director is not, and has not been for at least three years, one of our employees and that neither the director nor any of his or her family members has engaged in various types of business dealings with us. In addition, under applicable Nasdaq rules, a director will only qualify as an “independent director” if, in the opinion of the listed company’s board of directors, that person does not have a relationship that would interfere with the exercise of independent judgment in carrying out the responsibilities of a director. In order to be considered independent for purposes of Rule 10A-3, a member of an audit committee of a listed company may not, other than in his or her capacity as a member of the audit committee, the board of directors, or any other board committee, accept, directly or indirectly, any consulting, advisory, or other compensatory fee from the listed company or any of its subsidiaries or otherwise be an affiliated person of the listed company or any of its subsidiaries. In order to be considered independent for purposes of Rule 10C-1, the board must consider, for each member of a compensation committee of a listed company, all

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factors specifically relevant to determining whether a director has a relationship to such company which is material to that director’s ability to be independent from management in connection with the duties of a compensation committee member, including, but not limited to: (1) the source of compensation of the director, including any consulting, advisory or other compensatory fee paid by such company to the director; and (2) whether the director is affiliated with the company or any of its subsidiaries or affiliates.

Our Board of Directors has determined that all members of the Board of Directors, except Alexander Cumbo, are independent directors, as defined under applicable Nasdaq rules. In making such determinations, our Board of Directors considered the relationships that each director has with our Company and all other facts and circumstances that our Board of Directors deemed relevant in determining his or her independence, including the beneficial ownership of our common stock by each director. Mr. Cumbo is not an independent director under applicable rules because he is our President and Chief Executive Officer.

Our Board of Directors has determined that the composition of our committees currently complies with all applicable independence requirements of Nasdaq and the rules and regulations of the SEC.

Board Leadership Structure

It is the current policy of the Company that the positions of chief executive officer and chairman of the Board are held by different persons. Accordingly, our Board of Directors has appointed Mr. Smith as the chairman of the Board of Directors. Mr. Smith’s duties as chairman of the Board include the following:

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meeting with any director who is not adequately performing his or her duties as a member of our Board of Directors or any committee;

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facilitating communications between other members of our Board of Directors and the chief executive officer;

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preparing or approving the agenda for each board meeting; and

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determining the frequency and length of board meetings and recommending when special meetings of our Board of Directors should be held.

Our Board of Directors believes that having a leadership structure with separate roles of chairman and chief executive officer offers the following benefits:

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supporting the oversight of the Company and enhancing our Board’s objective evaluation of our chief executive officer;

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freeing the chief executive officer to focus on company operations instead of Board administration;

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providing the chief executive officer with an experienced sounding board; and

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providing greater opportunities for communication between stockholders and our Board of Directors.

Although the roles of chairman and chief executive officer are currently separate, our Board of Directors believes it is appropriate for our chief executive officer to serve as a member of our Board of Directors.

The Board’s Role in Risk Oversight

Our Board of Directors oversees our risk management processes directly and through its committees. Our management is responsible for risk management on a day-to-day basis. The role of our Board of Directors and its committees is to oversee the risk management activities of management. Our Board of Directors fulfills this duty by discussing with management the policies and practices utilized by management in assessing and managing risks and providing input on those policies and practices.

In general, our Board of Directors oversees risk management activities relating to business strategy, acquisitions, capital allocation, organizational structure and certain operational risks; our audit committee oversees risk management activities related to financial controls, legal and compliance risks and cybersecurity risks; our compensation committee oversees risk management activities relating to our compensation policies and practices; our nominating and corporate governance committee oversees risk management activities relating to the composition of our Board of Directors and the committees thereof, corporate governance and management succession planning; and our clinical committee assists the Board’s oversight of clinical and regulatory-related activities. Oversight by the audit committee includes direct communication with our

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independent registered public accounting firm. Oversight by the compensation committee includes direct communication with our independent compensation consultants. Each committee reports to the full Board of Directors on a regular basis, including reports with respect to the committee’s risk oversight activities as appropriate. In addition, since risk issues often overlap, committees from time to time request that the full Board of Directors discuss particular risks.

Board Meetings

Our Board met five times during fiscal year 2025, including telephonic and virtual meetings. During the year, each of our incumbent directors attended 75% or more of the combined total number of meetings of the Board and the committees on which he or she served.

Committees of the Board

We have four standing committees: the audit committee, the compensation committee, the nominating and corporate governance committee and the clinical committee. Each of these committees has a written charter approved by our Board. A copy of each charter can be found on the “Governance & Financials” section of the “Investors & Media” page of our website at www.solidbio.com.

Audit Committee

The members of our audit committee are Ms. Sullivan, Dr. Keresty and Mr. Stone, with Ms. Sullivan serving as chair of the audit committee. Our Board of Directors has determined that each of these individuals meets the independence requirements of the Sarbanes-Oxley Act, Rule 10A-3 under the Exchange Act, and the applicable listing standards of Nasdaq. Each member of our audit committee can read and understand fundamental financial statements in accordance with Nasdaq audit committee requirements. In arriving at this determination, the Board of Directors has examined each audit committee member’s employment and other experience. Our Board of Directors has determined that Ms. Sullivan qualifies as an audit committee financial expert within the meaning of SEC regulations and meets the financial sophistication requirements of the Nasdaq listing rules. In making this determination, our Board of Directors has considered Ms. Sullivan’s formal education and previous experience in financial roles. Both our independent registered public accounting firm and management periodically meet privately with our audit committee. Our audit committee met four times during fiscal year 2025.

Our audit committee’s responsibilities include, among other things:

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appointing, approving the compensation of, and assessing the independence of our registered public accounting firm;

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overseeing the work of our independent registered public accounting firm, including through the receipt and consideration of reports from that firm;

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reviewing and discussing with management and our independent registered public accounting firm our annual and quarterly financial statements and related disclosures;

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monitoring our internal control over financial reporting, disclosure controls and procedures and Code of Conduct;

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overseeing our risk assessment and risk management policies;

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overseeing cybersecurity risks;

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establishing procedures for the receipt and retention of accounting related complaints and concerns;

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meeting independently with our internal auditing staff, if any, our independent registered public accounting firm and management;

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reviewing and approving or ratifying any related person transactions;

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reviewing on a periodic basis our investment policy; and

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preparing the audit committee report required by SEC rules.

We believe that the composition and functioning of our audit committee complies with all applicable requirements of the Sarbanes-Oxley Act, and all applicable SEC and Nasdaq rules and regulations.

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Compensation Committee

The members of our compensation committee are Dr. Keresty, Dr. Freed and Dr. Nagendran, with Dr. Keresty serving as chair of the compensation committee. Our Board of Directors has determined that each of these individuals is independent as defined under the applicable listing standards of Nasdaq, including the standards specific to members of a compensation committee. Our compensation committee met six times during fiscal year 2025.

Our compensation committee’s responsibilities include, among other things:

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reviewing and approving, or making recommendations to our Board of Directors with respect to, the compensation of our chief executive officer and our other executive officers;

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overseeing an evaluation of our senior executives;

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overseeing and administering our cash and equity incentive plans;

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reviewing and making recommendations to our Board of Directors with respect to director compensation;

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reviewing and discussing annually with management our “Compensation Discussion and Analysis” disclosure if and to the extent then required by SEC rules; and

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preparing the compensation committee report if and to the extent then required by SEC rules.

We believe that the composition and functioning of our compensation committee complies with all applicable requirements of the Sarbanes-Oxley Act, and all applicable SEC and Nasdaq rules and regulations.

The compensation committee may delegate to one or more executive officers the power to grant options or other stock awards pursuant to our equity incentive plans to employees who are not directors or executive officers, subject to certain limitations. The compensation committee may also form and delegate its responsibilities to one or more subcommittees of the Board.

Our executive compensation program is administered by our compensation committee, subject to the oversight and approval of our full Board. Our compensation committee reviews our executive compensation practices on an annual basis and based on this review approves or, as appropriate, makes recommendations to our Board for approval of our executive compensation program. Our chief executive officer recommends annual executive salary increases, annual equity awards and bonuses, if any, for the other executive officers, which are then reviewed and approved or adjusted by the compensation committee.

In designing our executive compensation program, our compensation committee considers publicly available compensation data for national and regional companies in the biotechnology/pharmaceutical industry to help guide its executive compensation decisions at the time of hiring and for subsequent adjustments in compensation. In 2025, our compensation committee retained Radford, an AON Hewitt company, as its independent compensation consultant to provide comparative data on executive compensation practices in our industry and to advise on our executive compensation program generally. The compensation committee also retained Radford for recommendations and review of non-employee director compensation in 2025. Although our compensation committee considers the advice and recommendations of Radford as to our executive compensation program, our compensation committee ultimately makes their own decisions about these matters. In the future, we expect that our compensation committee will continue to engage independent compensation consultants to provide additional guidance on our executive compensation programs and to conduct further competitive benchmarking against a peer group of publicly traded companies.

Our director compensation program is administered by our Board with the assistance of the compensation committee. Our Board reviews our director compensation practices on an annual basis and may make adjustments to our director compensation program from time to time.

Nominating and Corporate Governance Committee

The members of our nominating and corporate governance committee are Mr. Stone, Dr. Kahn and Ms. Sullivan, with Mr. Stone serving as chair of the nominating and corporate governance committee. Our Board of Directors has determined that each of these individuals is independent as defined under the applicable listing standards of Nasdaq and SEC rules and regulations. Our nominating and corporate governance committee met one time during fiscal year 2025.

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Our nominating and corporate governance committee’s responsibilities include, among other things:

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recommending to our Board of Directors the persons to be nominated for election as directors and to each of our Board’s committees;

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reviewing and making recommendations to our Board of Directors with respect to our board leadership structure;

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reviewing and making recommendations to our Board of Directors with respect to management succession planning;

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developing and recommending to our Board of Directors corporate governance guidelines; and

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overseeing an annual evaluation of our Board of Directors.

We believe that the composition and functioning of our nominating and corporate governance committee complies with all applicable requirements of the Sarbanes-Oxley Act, and all applicable SEC and Nasdaq rules and regulations.

Clinical Committee

The members of our clinical committee are Dr. Freed, Dr. Kahn and Dr. Nagendran, with Dr. Freed serving as the chair of the clinical committee. Our clinical committee met six times during fiscal year 2025.

Our clinical committee’s responsibilities include, among other things:

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providing strategic and/or operational clinical development and regulatory advice and making recommendations to management of the Company, as applicable, regarding current and planned research and development programs;

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providing strategic and/or operation clinical and regulatory advice and guidance to management of the Company, as applicable, regarding advancement of clinical studies or programs; and

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advising the Board, as requested, regarding potential clinical and/or regulatory issues related to potential licensing and acquisition opportunities.

Code of Conduct

We have adopted a Code of Conduct that applies to our directors, executive officers and employees, including our principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions. The Code of Conduct is available on the “Governance & Financials” section of the “Investors & Media” page of our website at www.solidbio.com. Our Board of Directors and the audit committee of our Board of Directors are responsible for overseeing the Code of Conduct. We intend to post on our website all disclosures that are required by law or the listing standards of Nasdaq concerning any amendments to, or waivers of, any provision of the Code of Conduct.

Clawback Policy

Effective October 2, 2023, we adopted a compensation recovery policy, or a “clawback policy”, relating to our right to recover compensation previously paid to specified executive officers in certain circumstances, including the recovery of erroneously awarded incentive-based compensation (as defined in the policy) in accordance with Nasdaq Listing Rule 5608, which implements Rule 10D-1 under the Exchange Act. The policy is administered by the compensation committee.

The policy provides that, in the event that we are required to prepare an accounting restatement due to our material noncompliance with any financial reporting requirement under U.S. federal securities laws, including any required accounting restatement to correct an error in previously issued financial statements that is material to the previously issued financial statements, or that would result in a material misstatement if the error were corrected in the current period or left uncorrected in the current period, we will attempt to recover, reasonably promptly from each covered executive, any erroneously awarded incentive-based compensation received by our covered executives during the recovery period under the policy.

For purposes of this policy, covered executives refers to any executive officer (as defined in Rule 16a-1(f) under the Exchange Act) who served at any time during the performance period for the applicable incentive-based compensation. Incentive-based

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compensation means any compensation that is granted, earned or vested based wholly or in part upon the attainment of (i) any measures that are determined and presented in accordance with the accounting principles used in preparing our financial statements, and any measures that are derived wholly or in part from such measures, (ii) stock price and (iii) total stockholder return. Erroneously awarded incentive-based compensation means the amount of incentive-based compensation that was received that exceeds the amount of incentive-based compensation that otherwise would have been received had it been determined based on the restated amounts, computed without regard to any taxes paid by the covered executives (or by us on their behalf). If the incentive-based compensation is based on our stock price or total stockholder return and the amount of the erroneously awarded incentive-based compensation is not subject to recalculation directly from the information in an accounting restatement, the amount to be recovered shall be based on a reasonable estimate by the compensation committee of the effect of the accounting restatement on the stock price or total stockholder return upon which the incentive-based compensation was received. The policy does not apply to compensation received prior to October 2, 2023 or to compensation that was received by a covered executive before beginning service as an executive officer.

Director Nomination Process

Our nominating and corporate governance committee is responsible for identifying individuals qualified to serve as directors, consistent with criteria approved by our Board, and recommending the persons to be nominated for election as directors.

Director Qualifications

In evaluating director nominees, the nominating and corporate governance committee and our Board will consider, among other things, the following factors:

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relevant expertise upon which to be able to offer advice and guidance to management;

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having sufficient time to devote to the affairs of the Company;

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demonstrated excellence in his or her field;

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dedication to the Company’s mission;

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having the ability to exercise sound business judgment;

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having the commitment to represent the interests of the Company’s stockholders; and

•

having different experiences, perspectives and backgrounds.

The nominating and corporate governance committee’s goal is to assemble a Board that brings to the Company a variety of perspectives and skills derived from high quality business and professional experience. Moreover, the nominating and corporate governance committee believes that the background and qualifications of the Board, considered as a group, should provide a significant mix of experience, knowledge and abilities that will allow the Board to fulfill its responsibilities. Nominees are not discriminated against on the basis of race, religion, national origin, sex, sexual orientation, disability or any other basis proscribed by law.

The nominating and corporate governance committee has not adopted a formal policy with respect to a fixed set of specific minimum qualifications for its candidates for membership on the Board. The committee may consider such other facts as it may deem are in the best interests of the Company and its stockholders. The committee believes it is appropriate for our chief executive officer to serve as a member of our Board. Our directors’ performance and qualification criteria are reviewed periodically by the nominating and corporate governance committee.

Identification and Evaluation of Nominees for Directors

The nominating and corporate governance committee identifies nominees for director by first evaluating the current members of our Board willing to continue in service. Current members with qualifications and skills that are consistent with the nominating and corporate governance committee’s criteria for Board service and who are willing to continue in service are considered for re-nomination, balancing the value of continuity of service by existing members of our Board with that of obtaining a new perspective or expertise.

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If any member of our Board does not wish to continue in service or if our Board decides not to re-nominate a member for re-election, the nominating and corporate governance committee will identify a new nominee that meets the criteria above. The committee generally inquires of our Board and members of management for their recommendations. The committee may also review the composition and qualification of the boards of directors of our competitors and may seek input from industry experts or analysts. The nominating and corporate governance committee reviews the qualifications, experience and background of suggested candidates. Final candidates, if other than our current directors, would be interviewed by the members of the nominating and corporate governance committee and by certain of our other independent directors and executive management. In making its determinations, the nominating and corporate governance committee evaluates each individual in the context of our Board as a whole, with the objective of assembling a group that can best contribute to the success of the Company and represent stockholder interests through the exercise of sound judgment. After review and deliberation of all feedback and data, the nominating and corporate governance committee makes its recommendation to our Board.

We have not received director candidate recommendations from our stockholders and do not have a formal policy regarding consideration of such recommendations. However, any recommendations received from stockholders will be evaluated in the same manner that potential nominees suggested by Board members, management or other parties are evaluated. We do not intend to treat stockholder recommendations in any manner different from other recommendations.

Under our bylaws, stockholders wishing to propose a candidate for director should write to our secretary. In order to give the nominating and corporate governance committee sufficient time to evaluate a recommended candidate and/or include the candidate in our proxy statement for the 2027 annual meeting of stockholders, the recommendation should be received by our secretary at our principal executive offices in accordance with our procedures detailed in the section below entitled “Stockholder Proposals”. Such submissions must state the nominee’s name, together with appropriate biographical information and background materials, and information with respect to the stockholder or group of stockholders making the recommendation, including the number of shares of common stock owned by such stockholder or group of stockholders, as well as other information required by our bylaws. We may require any proposed nominee to furnish such other information as we may reasonably require to determine the eligibility of such proposed nominee to serve as an independent director or that could be material to a reasonable stockholder’s understanding of the independence, or lack thereof, of such proposed nominee.

Director Attendance at Annual Meetings

Our corporate governance guidelines provide that directors are responsible for attending the annual meeting of stockholders. Each then-serving director attended our 2025 annual meeting of stockholders.

Communications with Our Board

Stockholders seeking to communicate with our Board should submit their written comments to Solid Biosciences Inc., 500 Rutherford Avenue, 3rd Floor, Charlestown, Massachusetts 02129, Attention: Secretary. Our secretary will forward such communications to each member of our Board; provided that, if in the opinion of our secretary, it would be inappropriate to send a particular stockholder communication to a specific director, such communication will only be sent to the remaining directors (subject to the remaining directors concurring with such opinion).

Non-Employee Director Compensation

Non-employee director compensation is set by our Board of Directors at the recommendation of our compensation committee. In 2025, the compensation committee retained Radford, an AON Hewitt company, to assist in assessing our non-employee director compensation program and provide recommendations with respect to the compensation program.

Under our current director compensation program, we pay our non-employee directors a cash retainer for their service on the Board of Directors and for their service on each committee of which the director is a member. The chairs of each committee receive higher retainers for such service. These fees are payable in arrears in equal semi-annual installments not later than the 15th business day following the end of the second and fourth calendar quarters, provided that the amount of such payment will be prorated for any portion of such semi-annual period that the director is not serving on the Board of Directors, on such

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committee or in such position. The fees paid to non-employee directors for their service on the Board of Directors and for their service on each committee of the Board of Directors of which the director is a member are as follows:


	Member Annual Fee ($)		Chairperson Incremental Annual Fee ($)
Board of Directors		40,000		35,000
Audit Committee		10,000		10,000
Clinical Committee		7,500		7,500
Compensation Committee		6,000		6,000
Nominating and Corporate Governance Committee		5,000

SEC Form PRE 14A filed by Solid Biosciences Inc.