EX-10.3

Exhibit 10.3

Lock-Up Agreement

March 1, 2026

Ladies and Gentlemen:

The undersigned (the “Stockholder”) understands that: (i) RALLYBIO CORPORATION., a Delaware corporation (“Parent”), has entered into an Agreement and Plan of Merger and Reorganization, dated as of March 1, 2026 (the “Merger Agreement”), with CANDID THERAPEUTICS, INC., a Delaware corporation (the “Company”), and Farmington Merger Sub, Inc., a Delaware corporation and wholly-owned subsidiary of Parent (“Merger Sub”), pursuant to which at the effective time (the “Effective Time”), Merger Sub will be merged with and into the Company (the “Merger”) and the separate corporate existence of Merger Sub shall cease and the Company will continue as the surviving corporation; and (ii) in connection with the Merger, the stockholders of the Company will receive shares of common stock, par value $0.0001 per share, of Parent (“Parent Common Stock”). Annex A sets forth definitions for certain capitalized terms used in this agreement that are not defined in the body of this agreement. Those definitions are a part of this agreement. Other capitalized terms used but not otherwise defined herein shall have the respective meanings ascribed to such terms in the Merger Agreement.

As a material inducement to the willingness of each of the parties to enter into the Merger Agreement and to consummate the Contemplated Transactions, and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the Stockholder hereby agrees that the Stockholder will not, subject to the exceptions set forth in this letter agreement, during the period commencing upon the Effective Time and ending on the date that is 180 days after the Effective Time (the “Restricted Period”), (a) Sell or Offer to Sell, any shares of Parent Common Stock or any securities convertible into or exercisable or exchangeable for Parent Common Stock, including without limitation, Parent Common Stock or such other securities which may be deemed to be beneficially owned by the Stockholder or such Stockholder’s Family Member, in accordance with the rules and regulations of the U.S. Securities and Exchange Commission and securities of Parent which may be issued upon exercise or settlement of a stock option or other equity award (collectively, “Shares”), (b) enter into any Swap, short sale, hedge or other agreement that transfers, in whole or in part, any of the economic consequences of ownership of the Shares, regardless of whether any such transaction described in clause (a) or (b) above is to be settled by delivery of Parent Common Stock or such other securities, in cash or otherwise, (c) make any demand for or exercise any right with respect to the registration of any shares of Parent Common Stock or any security convertible into or exercisable or exchangeable for Parent Common Stock, or cause to be filed a registration statement, prospectus or prospectus supplement (or an amendment or supplement thereto) with respect to such registration or (d) publicly announce any intention to do any of the foregoing, in each case other than:

(i) transfers of Shares as bona fide charitable contributions, gifts or donations;

(ii) transfers or dispositions of Shares to any Family Member or any trust for the direct or indirect benefit of the Stockholder and/or the Family Member of the Stockholder;

(iii) transfers or dispositions of Shares by will, other testamentary document or intestate succession to the legal representative, heir, beneficiary or a member of the Immediate family of the Stockholder;

(iv) transfers of Shares to stockholders, direct or indirect Affiliates, current or former partners (general or limited), members or managers of the Stockholder, as applicable, or to the estates of any such stockholders, Affiliates, partners, members or managers, or to another corporation, partnership, limited liability company or other business entity that controls, is controlled by or is under common control with the Stockholder;

(v) transfers that occur by operation of law pursuant to a court order or settlement agreement related to the distribution of assets in connection with the dissolution of a marriage or civil union;

(vi) transfers or dispositions not involving a change in beneficial ownership;

(vii) if the Stockholder is a trust, transfers or dispositions to any beneficiary of the Stockholder or the estate of any such beneficiary;

(viii) transfers pursuant to a bona fide third party tender offer, merger, consolidation or other similar transaction made to all holders of the Parent’s capital stock involving a change of control of the Parent, provided that in the event that such tender offer, merger, consolidation or other such transaction is not completed, the Shares shall remain subject to the restrictions contained in this letter agreement;

(ix) transfers of Parent Common Stock, if any, issued in connection with the Concurrent Financing;

provided, that in each case of clauses (i)-(vii), (a) other than with respect to clauses (i), (iii), (iv), (v) and (vii), no filing by any party (including any donor, donee, transferor or transferee, distributor or distributee) under the Exchange Act or other public announcement shall be required or shall be made voluntarily in connection with such transfer or distribution (other than filings made in respect of involuntary transfers or dispositions or a filing on a Form 5 made after the expiration of the Restricted Period), (b) other than with respect to clause (iv), any such transfer or distribution shall not involve a disposition for value, and (c) the transferee or donee agrees in writing to be bound by the terms and conditions of this letter agreement and either the Stockholder or the transferee or donee provides Parent with a copy of such agreement promptly upon consummation of any such transfer.

Notwithstanding the restrictions imposed by this letter agreement, the Stockholder may (a) exercise or settle an option to purchase Shares or other equity award (including a net or cashless exercise of such option) and provided further, that the underlying Shares shall continue to be subject to the restrictions on transfer set forth in this letter agreement, (b) transfer Shares to Parent to cover tax withholding obligations of the Stockholder in connection with the vesting, settlement or exercise of such options or other equity awards, as applicable, (c) establish a trading plan pursuant to Rule 10b5-1 under the Exchange Act (“10b5-1 Plan”) for the transfer of Shares, provided that such plan does not provide for any transfers of Shares during the Restricted Period and, provided further, that, no filing under the Exchange Act or other public announcement shall be made voluntarily in connection with the establishment of such a plan, (d) transfer Shares to Parent pursuant to arrangements under which Parent has the option to repurchase such Shares, or (e) transfer or dispose of Shares acquired on the open market following the Effective Time.

Any attempted transfer in violation of this letter agreement will be of no effect and null and void, regardless of whether the purported transferee has any actual or constructive knowledge of the transfer restrictions set forth in this letter agreement, and will not be recorded on the share register of Parent. To ensure compliance with the restrictions referred to herein, the Stockholder agrees that Parent and any duly appointed transfer agent may issue appropriate “stop transfer” certificates or instructions. Parent may cause the legend set forth below, or a legend substantially equivalent thereto, to be placed upon any certificate(s) or other documents or instruments evidencing ownership of the Shares:

THE SHARES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO AND MAY ONLY BE TRANSFERRED IN COMPLIANCE WITH A LOCK-UP AGREEMENT, A COPY OF WHICH IS ON FILE AT THE PRINCIPAL OFFICE OF THE COMPANY.

The Stockholder hereby represents and warrants that the Stockholder has full power and authority to enter into this letter agreement. All authority conferred or agreed to be conferred and any obligations of the Stockholder under this letter agreement will be binding upon the successors, assigns, heirs or personal representatives of the Stockholder.

In the event that any holder of Parent’s securities that is subject to a substantially similar agreement entered into by such holder, other than the Stockholder, is granted a release or waiver of the foregoing restrictions by Parent with respect to any shares of Parent Common Stock for value other than as permitted by this or a substantially similar agreement entered into by such holder, the same percentage of shares of Parent Common Stock held by the Stockholder shall be immediately and fully released on the same terms from any remaining restrictions set forth herein (the “Pro-Rata Release”); provided, however, that such Pro-Rata Release shall not be applied unless and until permission has been granted by Parent, to an equity holder or equity holders to sell or otherwise transfer or dispose of all or a portion of such equity holders’ shares of Parent Common Stock in an aggregate amount in excess of 1% of the number of shares of Parent Common Stock outstanding immediately following the Effective Time; provided further that if the Stockholder is an executive officer or director of Parent and such release or waiver was conducted solely for the purpose of meeting Nasdaq’s initial listing standards, then such Stockholder shall not be entitled to such Pro-Rata Release.

Upon the release of any Shares from this letter agreement, Parent will cooperate with the Stockholder to facilitate the timely preparation and delivery of certificates or the establishment of book entry positions at the Parent’s transfer agent representing the Shares without the restrictive legend above and the withdrawal of any stop transfer instructions at the Parent’s transfer agent.

The Stockholder understands that each of Parent and the Company is relying upon this letter agreement in proceeding toward consummation of the Merger. The Stockholder further understands that this letter agreement is irrevocable and is binding upon the Stockholder’s heirs, legal representatives, successors and assigns.

This letter agreement and any claim, controversy or dispute arising under or related to this letter agreement shall be governed by and construed in accordance with the laws of the State of Delaware, without regard to the conflict of laws principles thereof.

The Stockholder understands that if the Merger Agreement is terminated in accordance with its terms, the Stockholder will be released from all obligations under this letter agreement.

The undersigned hereby represents that the undersigned has full power, capacity and authority to enter into this agreement. This letter agreement may be executed by electronic (i.e., PDF) transmission, which is deemed an original.

[Signature Page Follows]


	Very truly yours,

Print Name of Stockholder:

	Signature (for individuals):



	Signature (for entities):

	By:

		Name:

		Title:

[SIGNATURE PAGE TO LOCK-UP AGREEMENT]

Certain Defined Terms

Used in Lock-up Agreement

For purposes of the agreement to which this Annex A is attached and of which it is made a part:

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“Affiliate” shall have the meaning set forth in Rule 405 under the Securities Act.

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“Call Equivalent Position” shall have the meaning set forth in Rule 16a-1(b) under the Exchange Act.

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“Exchange Act” shall mean the Securities Exchange Act of 1934, as amended.

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“Family Member” shall mean the spouse of the undersigned, an immediate family member of the undersigned or an immediate family member of the undersigned’s spouse, in each case living in the undersigned’s household or whose principal residence is the undersigned’s household (regardless of whether such spouse or family member may at the time be living elsewhere due to educational activities, health care treatment, military service, temporary internship or employment or otherwise). “Immediate family member” as used above shall have the meaning set forth in Rule 16a-1(e) under the Exchange Act.

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“Immediate Family” shall mean any relationship by blood, marriage or adoption, not more remote than first cousin.

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Put Equivalent Position” shall have the meaning set forth in Rule 16a-1(h) under the Exchange Act.

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“Securities Act” shall mean the Securities Act of 1933, as amended.

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“Sell or Offer to Sell” shall mean to:

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sell, offer to sell, contract to sell or lend,

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effect any short sale or establish or increase a Put Equivalent Position or liquidate or decrease any Call Equivalent Position,

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pledge, hypothecate or grant any security interest in, or

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in any other way transfer or dispose of,

in each case whether effected directly or indirectly.

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“Swap” shall mean any swap, hedge or similar arrangement or agreement that transfers, in whole or in part, the economic risk of ownership of Shares, regardless of whether any such transaction is to be settled in securities, in cash or otherwise.

Capitalized terms not defined in this Annex A shall have the meanings given to them in the body of this agreement.