Form of Support and Joinder Agreement

EXHIBIT 10.2

FORM OF SUPPORT AND JOINDER AGREEMENT

This Support and Joinder Agreement (this “Agreement”) is made and entered into as of ________________, 2022, by and among AavantiBio, Inc., a Delaware corporation (the “Company”), Solid Biosciences Inc., a Delaware corporation (“Parent”), and the undersigned stockholder (the “Stockholder”) of the Company. Capitalized terms used herein but not otherwise defined shall have the respective meanings ascribed to such terms in the Merger Agreement (as defined below).

RECITALS

WHEREAS, concurrently with the execution and delivery hereof, Parent, the Company, Greenland Merger Sub LLC, a Delaware limited liability company and a wholly owned subsidiary of Parent (the “Transitory Subsidiary”), have entered into an agreement and plan of merger (as such agreement may be amended or supplemented from time to time pursuant to the terms thereof, the “Merger Agreement”), pursuant to which Transitory Subsidiary will merge with and into the Company, whereby Transitory Subsidiary will cease to exist and the Company will survive as a direct, wholly owned subsidiary of Parent (the “Merger”), upon the terms and subject to the conditions set forth in the Merger Agreement.

WHEREAS, as of the date hereof, the Stockholder is the beneficial owner (as defined in Rule 13d-3 under the Exchange Act) of such number of shares of Company Capital Stock as indicated in Appendix A.

WHEREAS, as an inducement to the willingness of Parent to enter into the Merger Agreement, Parent has required that Stockholder enter into this Agreement.

NOW, THEREFORE, intending to be legally bound, the parties hereby agree as follows:

1. Certain Definitions. Capitalized terms used but not otherwise defined herein shall have the meanings ascribed thereto in the Merger Agreement. For all purposes of this Agreement, the following terms shall have the following respective meanings:

(a) “Company Capital Stock” means the Company Common Stock and Company Preferred Stock.

(b) “Constructive Sale” means, with respect to any security, a short sale with respect to such security, entering into or acquiring a derivative contract with respect to such security, entering into or acquiring a futures or forward contract to deliver such security or entering into any other hedging or other derivative transaction that has the effect of either directly or indirectly materially changing the economic benefits or risks of ownership of such security.

(c) “Shares” means (i) all shares of Company Capital Stock beneficially owned by the Stockholder as of the date hereof, and (ii) all additional shares of Company Capital Stock acquired and beneficially owned by the Stockholder during the period commencing with the execution and delivery of this Agreement and expiring on the Closing Date.

(d) “Transfer” or “Transferred” means, with respect to any security, the direct or indirect assignment, sale, transfer, tender, exchange, pledge or hypothecation, or the grant, creation or suffrage of a lien, security interest or encumbrance in or upon, or the gift, grant or placement in trust, or the Constructive Sale or other disposition of such security (including transfers by testamentary or intestate succession, by domestic relations order or other court order, or otherwise by operation of law) or any right, title or interest therein (including any right or power to vote to which the holder thereof may be entitled, whether such right or power is granted by proxy or otherwise), or the beneficial ownership thereof, the offer to make such a sale, transfer, Constructive Sale or other disposition, and each agreement, arrangement or understanding, whether or not in writing, to effect any of the foregoing.

2. Transfer and Voting Restrictions. The Stockholder covenants to Parent as follows:

(a) Except as otherwise permitted by Section 2(c), during the period commencing with the execution and delivery of this Agreement and expiring on the Expiration Date (as defined below), the Stockholder shall not Transfer any of the Stockholder’s Shares, or publicly announce its intention to Transfer any of its Shares.

(b) Except as otherwise permitted by this Agreement or otherwise permitted or required by order of a court of competent jurisdiction or a Governmental Entity, the Stockholder will not commit any act that would restrict the Stockholder’s legal power, authority and right to vote all of the Shares held by the Stockholder or otherwise prevent or disable the Stockholder from performing any of his, her or its obligations under this Agreement. Without limiting the generality of the foregoing, except for this Agreement, the Voting Agreement of the Company, dated as of October 21, 2020 (the “Voting Agreement”) and as otherwise permitted by this Agreement, the Stockholder shall not enter into any voting agreement with any person or entity with respect to any of the Stockholder’s Shares, grant any person or entity any proxy (revocable or irrevocable) or power of attorney with respect to any of the Shares, deposit any Shares in a voting trust or otherwise enter into any agreement or arrangement with any person or entity limiting or affecting the Stockholder’s legal power, authority or right to execute and deliver the Written Consent or to adopt, approve, or otherwise provide or deliver the Company Stockholder Approval.

(c) Notwithstanding anything else herein to the contrary, the Stockholder may, at any time, Transfer Shares (i) by will or other testamentary document or by intestacy, (ii) to any investment fund or other entity controlled or managed by the Stockholder or the investment adviser or general partner of the Stockholder, or an entity under common control or management with the Stockholders (in each case, directly or indirectly) (iii) to any member of the Stockholder’s immediate family (or, if the Stockholder is a corporation, partnership or other entity, to an immediate family member of a beneficial owner of the Shares held by the Stockholder), (iv) to any trust or other entity for the direct or indirect benefit of the Stockholder or the immediate family of the Stockholder (or, if the Stockholder is a corporation, partnership or other entity, for the direct or indirect benefit of an immediate family member of a beneficial owner of the Shares held by the Stockholder) or otherwise for estate tax or estate planning purposes or (v) in the case of a Stockholder who is not a natural person, by pro rata distributions from the Stockholder to its members, partners, or shareholders pursuant to the Stockholder’s

organizational documents; provided, that in the cases of clauses (i) – (v), (x) such Transferred Shares shall continue to be bound by this Agreement and (y) the applicable direct transferee (if any) of such Transferred Shares shall have executed and delivered to Parent and the Company a support agreement substantially identical to this Agreement upon consummation of the Transfer.

3. Agreement to Vote Shares. The Stockholder covenants to the Company as follows:

(a) Until the Expiration Date, at any meeting of the stockholders of the Company, however called, and at every adjournment or postponement thereof, and on every action or approval by written consent of the stockholders of the Company, the Stockholder shall be present (in person or by proxy) and vote, or exercise its right to consent with respect to, all Shares held by the Stockholder (A) in favor of the adoption and approval of the Merger Agreement, (B) in favor of approval of the Contemplated Transactions, and (C) against any Acquisition Proposal.

(b) If the Stockholder is not the record holder of Shares, the Stockholder agrees to take all actions necessary to cause the record holder and any nominees to be present (in person or by proxy) and vote all the Stockholder’s Shares in accordance with this Section 3.

(c) In the event of a stock split, stock dividend or distribution, or any change in the capital stock of the Company by reason of any split-up, reverse stock split, recapitalization, combination, reclassification, reincorporation, exchange of shares or the like, the term “Shares” shall be deemed to refer to and include such shares as well as all such stock dividends and distributions and any securities into which or for which any or all of such shares may be changed or exchanged or which are received in such transaction.

4. Action in Stockholder Capacity Only. The Stockholder is entering into this Agreement solely in the Stockholder’s capacity as the beneficial owner of its Shares and not in the Stockholder’s capacity as a director or officer of the Company. Nothing herein shall limit or affect the Stockholder’s ability to act as an officer or director of the Company.

5. Irrevocable Proxy. The Stockholder hereby revokes (or agrees to cause to be revoked) any proxies that the Stockholder has heretofore granted with respect to its Shares. In the event and to the extent that the Stockholder fails to vote the Shares in accordance with Section 3 at any applicable meeting of the stockholders of the Company or pursuant to any applicable written consent of the stockholders of the Company (including, without limitation, the Written Consent), the Stockholder shall be deemed to have irrevocably granted to, and appointed, the Parent, and any individual designated in writing by it, and each of them individually, as his, her or its proxy and attorney-in-fact (with full power of substitution), for and in its name, place and stead, to vote his, her or its Shares in any action by written consent of Company stockholders (including, without limitation, the Written Consent) or at any meeting of the Company stockholders called with respect to any of the matters specified in, and in accordance and consistent with, Section 3 of this Agreement. The Parent agrees not to exercise the proxy granted herein for any purpose other than the purposes described in this Agreement. Except as otherwise provided for herein (including the next sentence), the Stockholder hereby affirms that the irrevocable proxy is coupled with an interest and may under no circumstances be revoked and that such irrevocable proxy is executed and intended to be irrevocable. Notwithstanding any other provisions of this Agreement, the irrevocable proxy granted hereunder shall automatically terminate upon the termination of this Agreement.

6. No Solicitation. Subject to Section 4, the Stockholder agrees not to, directly or indirectly, including through any of its officers, directors or agents, (a) solicit, seek or initiate or knowingly take any action to facilitate or encourage, any offers, inquiries or the making of any proposal or offer that constitutes, or could reasonably be expected to lead to, any Acquisition Proposal or Acquisition Inquiry or (b) enter into, continue or otherwise participate or engage in any discussions or negotiations regarding any Acquisition Proposal or Acquisition Inquiry, or furnish to any person any non-public information or afford any person, other than Parent or the Company, as applicable, access to such party’s property, books or records (except as required by applicable Law or pursuant to a request by a Governmental Entity) in connection with, any Acquisition Proposal or Acquisition Inquiry; provided, however, that nothing in this Section 6 shall prevent the Stockholder from referring a person to this Section 6 or to the Merger Agreement.

7. Documentation and Information. The Stockholder shall permit and hereby authorizes Parent and the Company to publish and disclose in all documents and schedules filed with the SEC, and any press release or other disclosure document that Parent or the Company reasonably determines to be necessary in connection with the Merger and any of the Contemplated Transactions, a copy of this Agreement, the Stockholder’s identity and ownership of the Shares and the nature of the Stockholder’s commitments and obligations under this Agreement; provided, that, Parent and the Company provide such documents, schedules, press release or other disclosure document to the Stockholder in advance for its review and comment. Each of Parent and the Company is an intended third-party beneficiary of this Section 7.

8. No Exercise of Appraisal Rights; Waivers. The Stockholder hereby irrevocably and unconditionally (a) waives, and agrees to cause to be waived and to prevent the exercise of, any rights of appraisal, any dissenters’ rights and any similar rights (including any notice requirements related thereto) relating to the Merger that Stockholder may have by virtue of, or with respect to, any Shares (including all rights under Section 262 of the DGCL) and (b) agrees that the Stockholder will not bring, commence, institute, maintain, prosecute or voluntarily aid or participate in any action, claim, suit or cause of action, in law or in equity, in any court or before any Governmental Entity, which (i) challenges the validity of or seeks to enjoin the operation of any provision of this Agreement or (ii) alleges that the execution and delivery of this Agreement by the Stockholder breaches any duty that such Stockholder has (or may be alleged to have) to the Company or to the other Company stockholders; provided, that (x) the Stockholder may defend against, contest or settle any such action, claim, suit or cause of action brought against the Stockholder that relates solely to the Stockholder’s capacity as a director, officer or securityholder of the Company and (y) the foregoing shall not limit or restrict in any manner the Stockholder from enforcing the Stockholder’s rights under this Agreement and the other agreements entered into by the Stockholder in connection herewith, or otherwise in connection with the Merger, including the Stockholder’s right to receive the Merger Consideration pursuant to the terms of the Merger Agreement.

9. Representations and Warranties of the Stockholder. The Stockholder hereby represents and warrants to the Company as follows:

(a) (i) The Stockholder is the beneficial owner of the shares of Company Capital Stock indicated in Appendix A (each of which shall be deemed to be “held” by the Stockholder for purposes of Section 3 unless otherwise expressly stated with respect to any shares in Appendix A), free and clear of any and all Encumbrances (except for any Encumbrance that may be imposed pursuant to this Agreement, the Voting Agreement, the Investors’ Rights Agreement of the Company, dated as of October 21, 2020 (the “Investors’ Rights Agreement”),or any lock-up agreement entered into by and between the Stockholder, the Company and Parent); and (ii) the Stockholder does not beneficially own any securities of the Company other than the shares of Company Capital Stock and rights to purchase shares of Company Capital Stock set forth in Appendix A.

(b) Except as otherwise provided in this Agreement, the Stockholder has full power and authority to (i) make, enter into and carry out the terms of this Agreement and (ii) vote all of its Shares in the manner set forth in this Agreement without the consent or approval of, or any other action on the part of, any other person or entity (including any Governmental Entity). Without limiting the generality of the foregoing, except for the Voting Agreement, the Stockholder has not entered into any voting agreement (other than this Agreement) with any person with respect to any of the Stockholder’s Shares, granted any person any proxy (revocable or irrevocable) or power of attorney with respect to any of the Stockholder’s Shares, deposited any of the Stockholder’s Shares in a voting trust or entered into any arrangement or agreement with any person limiting or affecting the Stockholder’s legal power, authority or right to vote the Stockholder’s Shares on any matter.

(c) This Agreement has been duly and validly executed and delivered by the Stockholder and (assuming the due authorization, execution and delivery by the other parties hereto) constitutes a valid and binding agreement of the Stockholder enforceable against the Stockholder in accordance with its terms, except as enforceability may be limited by bankruptcy, insolvency, reorganization, moratorium or similar Laws now or hereafter in effect relating to creditors’ rights generally and subject to general principles of equity. The execution and delivery of this Agreement by the Stockholder and the performance by the Stockholder of the agreements and obligations hereunder will not result in any breach or violation of or be in conflict with or constitute a default under any term of any Contract or if applicable any provision of an organizational document (including a certificate of incorporation) to or by which the Stockholder is a party or bound, or any applicable law to which the Stockholder (or any of the Stockholder’s assets) is subject or bound, except for any such breach, violation, conflict or default which, individually or in the aggregate, would not reasonably be expected to materially impair or adversely affect the Stockholder’s ability to perform its obligations under this Agreement.

(d) The execution, delivery and performance of this Agreement by the Stockholder do not and will not require any consent, approval, authorization or permit of, action by, filing with or notification to, any Governmental Entity, except for any such consent, approval, authorization, permit, action, filing or notification the failure of which to make or obtain, individually or in the aggregate, has not and would not materially impair the Stockholder’s ability to perform its obligations under this Agreement.

(e) The Stockholder has had the opportunity to review the Merger Agreement and this Agreement with counsel of the Stockholder’s own choosing. The Stockholder has had an opportunity to review with its own tax advisors the tax consequences of the Merger and the Contemplated Transactions. The Stockholder understands that it must rely solely on its advisors and not on any statements or representations made by Parent, the Company or any of their respective agents or representatives with respect to the tax consequences of the Merger and the Contemplated Transactions. The Stockholder understands that such Stockholder (and not Parent, the Company or the Surviving Corporation) shall be responsible for such Stockholder’s tax liability that may arise as a result of the Merger or the Contemplated Transactions. The Stockholder understands and acknowledges that the Company, Parent and the Transitory Subsidiary are entering into the Merger Agreement in reliance upon the Stockholder’s execution, delivery and performance of this Agreement.

(f) With respect to the Stockholder, as of the date hereof, there is no action, suit, investigation or proceeding pending against, or, to the knowledge of the Stockholder, threatened against, the Stockholder or any of the Stockholder’s properties or assets (including the Shares) that would reasonably be expected to prevent or materially delay or impair the ability of the Stockholder to perform its obligations hereunder or to consummate the transactions contemplated hereby.

10. Termination. This Agreement shall terminate and shall cease to be of any further force or effect as of the earliest of (a) such date and time as the Merger Agreement shall have been terminated pursuant to the terms thereof, (b) the Effective Time and (c) the time this Agreement is terminated upon the written agreement of the Stockholder, the Company and Parent (the “Expiration Date”); provided, however, that (i) Section 12 shall survive the termination of this Agreement, and (ii) the termination of this Agreement shall not relieve any party hereto from any liability for any material and willful breach of this Agreement prior to the Effective Time.

11. Joinder to Merger Agreement. Subject to the Closing, the Stockholder hereby agrees to be bound by Article I, Article II, Article V, Article VI, Article VII, Article VIII and, to the extent related to the foregoing, Article XI of the Merger Agreement, and all other provisions of the Merger Agreement that by their terms purport to bind the Company Equityholders or that are related to Article I, Article II, Article V, Article VI, Article VII, Article VIII and, to the extent related to the foregoing, Article XI of the Merger Agreement and, in each case, solely to the extent such sections are applicable to the Company Equityholders (collectively, the “Relevant Provisions”), subject to the limitations and qualifications contained in such provisions of the Merger Agreement and herein, solely in his, her or its capacity as a Company Equityholder as if a signatory to the Merger Agreement, and, in exchange for Parent’s agreement to make the payments to the Stockholder as contemplated by the Merger Agreement, the Stockholder shall comply with, and be subject to, all of the terms, conditions, covenants, agreements and obligations set forth in such Relevant Provisions solely as a Company Equityholder, as contemplated by the Merger Agreement.

12. Miscellaneous Provisions.

(a) Amendments. No amendment of this Agreement shall be effective against any party unless it shall be in writing and signed by each of the parties hereto.

(b) Entire Agreement. This Agreement constitutes the entire agreement between the parties to this Agreement and supersedes all other prior agreements, arrangements and understandings, both written and oral, among the parties with respect to the subject matter hereof.

(c) Governing Law. This Agreement (and any claims or disputes arising out of or related hereto or the transactions contemplated hereby or to the inducement of any party to enter herein, whether for breach of contract, tortious conduct or otherwise and whether predicated on common law, statute or otherwise) shall be governed in all respects, including validity, interpretation, and effect, by and construed in accordance with the internal Laws of the State of Delaware (including in respect of the statute of limitations or other limitations period applicable to any claim, controversy or dispute) without giving effect to any choice or conflict of Law provision or rule (whether of the State of Delaware or any other jurisdiction) that would cause the application of Laws of any jurisdictions other than those of the State of Delaware.

(d) Jurisdiction; Waiver of Jury Trial. Each of the parties to this Agreement (i) consents to submit itself to the exclusive personal jurisdiction of the Court of Chancery of the State of Delaware, New Castle County, or, if that court does not have jurisdiction, a federal court sitting in Wilmington, Delaware in any action or proceeding arising out of or relating to this Agreement or any of the transactions contemplated by this Agreement, (ii) agrees that all claims in respect of such action or proceeding may be heard and determined in any such court, (iii) agrees that it shall not attempt to deny or defeat such personal jurisdiction by motion or other request for leave from any such court, (iv) agrees not to bring any action or proceeding arising out of or relating to this Agreement or any of the transactions contemplated by this Agreement in any other court, and (v) waives any right it may have to a trial by jury with respect to any action or proceeding arising out of or relating to this Agreement. Each of the parties hereto waives any defense of improper venue or inconvenient forum to the maintenance of any action or proceeding so brought and waives any bond, surety or other security that might be required of any other party with respect thereto. Any party hereto may make service on another party by sending or delivering a copy of the process to the party to be served at the address and in the manner provided for the giving of notices in Section 12(j). Nothing in this Section 12(d), however, shall affect the right of any party to serve legal process in any other manner permitted by Law. Nothing in this Section 12(d) shall limit the right of a party to seek injunctive relief under Section 12(h) in any applicable jurisdiction

(e) Assignment. Except as otherwise provided in Section 2(c) hereof, no party may assign any of its rights or delegate any of its performance obligations under this Agreement, in whole or in part, by operation of law or otherwise, without the prior written consent of the other parties hereto, and any such assignment without such prior written consent shall be null and void, except that the Parent may transfer or assign its rights and obligations under this Agreement, in whole or from time to time in part, to one (1) or more of its Affiliates; provided, that such transfer or assignment shall not relieve the Parent of its primary liability for its obligations hereunder or enlarge, alter or change any obligations of any other party hereto or due to the Parent. Subject to the preceding sentence, this Agreement shall be binding upon, inure to the benefit of, and be enforceable by, the parties hereto and their respective successors and permitted assigns. Any purported assignment of rights or delegation of performance obligations in violation of this Section 12(e) is void.

(f) No Third Party Rights. This Agreement is not intended to, and shall not, confer upon any other person any rights or remedies hereunder other than the parties hereto to the extent expressly set forth herein.

(g) Severability. Any term or provision of this Agreement that is invalid or unenforceable in any situation in any jurisdiction shall not affect the validity or enforceability of the remaining terms and provisions hereof or the validity or enforceability of the offending term or provision in any other situation or in any other jurisdiction. If the final judgment of a court of competent jurisdiction declares that any term or provision hereof is invalid or unenforceable, the parties hereto agree that the court making such determination shall have the power to limit the term or provision, to delete specific words or phrases, or to replace any invalid or unenforceable term or provision with a term or provision that is valid and enforceable and that comes closest to expressing the intention of the invalid or unenforceable term or provision, and this Agreement shall be enforceable as so modified. In the event such court does not exercise the power granted to it in the prior sentence, the parties hereto agree to replace such invalid or unenforceable term or provision with a valid and enforceable term or provision that will achieve, to the extent possible, the economic, business and other purposes of such invalid or unenforceable term.

(h) Specific Performance. The parties hereto agree that irreparable damage would occur in the event that any of the provisions of this Agreement were not performed in accordance with their specific terms or were otherwise breached. It is accordingly agreed that the parties shall be entitled to an injunction or injunctions to prevent breaches of this Agreement and to enforce specifically the terms and provisions of this Agreement, in each case without posting a bond or undertaking, this being in addition to any other remedy to which they are entitled at Law or in equity. Each of the parties agrees that it will not oppose the granting of an injunction, specific performance and other equitable relief on the basis that (i) the party seeking such remedy has an adequate remedy at Law or (ii) an award of specific performance is not an appropriate remedy for any reason at Law or equity.

(i) Notices. All notices and other communications hereunder shall be in writing and shall be deemed to have been duly delivered and received hereunder (i) one Business Day after being sent for next Business Day delivery, fees prepaid, via a reputable international overnight courier service, (ii) upon delivery, in the case of delivery by hand, or (iii) on the date delivered in the place of delivery if sent by email or facsimile (with a written or electronic confirmation of delivery) prior to 6:00 p.m. New York City time, otherwise on the next succeeding Business Day, in each case to the intended recipient as follows: (A) if to the Company or Parent, to the address, electronic mail address or facsimile provided in the Merger Agreement, including to the persons designated therein to receive copies; and/or (B) if to the Stockholder, to the Stockholder’s address, electronic mail address or facsimile shown below Stockholder’s signature to this Agreement.

(j) Counterparts; Electronic Signature. This Agreement may be executed in two or more counterparts (including by facsimile, by an electronic scan delivered by electronic mail or any electronic signature), each of which shall be deemed an original but all of which together shall be considered one and the same agreement and shall become effective when counterparts have been signed by each of the parties hereto and delivered to the other parties, it being understood that all parties need not sign the same counterpart. This Agreement may be executed and delivered by facsimile, by an electronic scan delivered by electronic mail or by delivery of any electronic signature.

(k) Confidentiality. Except to the extent required by applicable Law or regulation, the Stockholder shall hold any non-public information regarding this Agreement, the Merger Agreement and the Merger in strict confidence and shall not divulge any such information to any third person until the Company has publicly disclosed its entry into the Merger Agreement and this Agreement; provided, however, that the Stockholder may disclose such information to its Affiliates, partners, members, stockholders, parents, subsidiaries, attorneys, accountants, consultants, trustees, beneficiaries and other representatives (provided that such Persons are subject to confidentiality obligations at least as restrictive as those contained herein). Neither the Stockholder nor any of its Affiliates (other than the Company, whose actions shall be governed by the Merger Agreement), shall issue or cause the publication of any press release or other public announcement with respect to this Agreement, the Merger, the Merger Agreement or the other transactions contemplated hereby or thereby without the prior written consent of the Company and Parent, except as may be required by applicable Law in which circumstance such announcing party shall make reasonable efforts to consult with the Company and Parent to the extent practicable.

(l) Interpretation. When reference is made in this Agreement to a Section or Appendix, such reference shall be to a Section of or Appendix to this Agreement, unless otherwise indicated. The headings contained in this Agreement are for convenience of reference only and shall not affect in any way the meaning or interpretation of this Agreement. The language used in this Agreement shall be deemed to be the language chosen by the parties hereto to express their mutual intent, and no rule of strict construction shall be applied against any party. Whenever the context may require, any pronouns used in this Agreement shall include the corresponding masculine, feminine or neuter forms, and the singular form of nouns and pronouns shall include the plural, and vice versa. Any reference to any federal, state, local or foreign statute or law shall be deemed also to refer to all rules and regulations promulgated thereunder, unless the context requires otherwise. Whenever the words “include,” “includes” or “including” are used in this Agreement, they shall be deemed to be followed by the words “without limitation.”

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IN WITNESS WHEREOF, the undersigned have caused this Agreement to be duly executed as of the date first above written.

Appendix A