As filed with the Securities and Exchange Commission on April 2, 2026

Registration No. 333-

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-8

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

Decoy Therapeutics Inc.

(Exact name of registrant as specified in its charter)

Decoy Therapeutics Inc. 2026 Equity Incentive Plan

Decoy Therapeutics Inc. 2020 Equity Incentive Plan

(Full title of the plans)

Mark Rosenblum

Chief Financial Officer

Decoy Therapeutics Inc.

2450 Holcombe Blvd., Suite X

Houston, TX 77021

(Name and address of agent for service)

(713) 913-5608

(Telephone number, including area code, of agent for service)

Copies to:

Jeffrey Kuras, Esq.

Michael J. Rosenberg, Esq.

Honigman LLP

2290 First National Building

600 Woodward Avenue

Detroit, MI 48226-3506

(313) 465-7454

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act.

EXPLANATORY NOTE

This registration statement on Form S-8 is being filed by Decoy Therapeutics Inc. (formerly known as Salarius Pharmaceuticals, Inc.), a Delaware corporation (the “Registrant”), to register 105,282 shares of the Registrant’s common stock, $0.0001 par value per share (the “Common Stock”), consisting of (i) 91,667 shares of Common Stock issuable under the Decoy Therapeutics Inc. 2026 Equity Incentive Plan (the “2026 Plan”), approved by the Registrant’s stockholders on February 24, 2026, which replaced the Registrant’s 2015 Equity Incentive Plan that expired by its terms in January 2025; and (ii) 13,615 shares of Common Stock issuable under the Decoy Therapeutics Inc. 2020 Equity Incentive Plan, assumed by the Registrant (formerly known as Salarius Pharmaceuticals, Inc.) in connection with its merger with Decoy Therapeutics Inc., a Delaware corporation (the “2020 Plan” and together with the 2026 Plan, the “Plans”).

The 2020 Plan was assumed by the Registrant pursuant to Section 1.9(a) of that certain Agreement and Plan of Merger dated January 10, 2025, as amended (the “Merger Agreement”), by and among the Registrant, Decoy Therapeutics MergerSub I, Inc., Decoy Therapeutics MergerSub II, LLC, and Decoy Therapeutics Inc. On November 12, 2025, the Registrant completed the acquisition of Decoy Therapeutics Inc. pursuant to the Merger Agreement. Pursuant to the Merger Agreement, each outstanding and unexercised option under the 2020 Plan was converted into an option to purchase Common Stock of the Registrant, with the number of shares and per share exercise price adjusted by the applicable exchange ratio, and all other terms and conditions of such options remaining unchanged.

PART I

INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

As permitted by the rules of the Securities and Exchange Commission (the “Commission”), this registration statement on Form S-8 omits the information specified in Part I of Form S-8. The documents containing the information specified in Part I will be delivered to the participants in the Plans covered by this registration statement as required by Rule 428(b)(1) under the Securities Act of 1933, as amended (the “Securities Act”).

PART II

INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3. Incorporation of Documents by Reference.

The following documents of the Registrant filed with the Commission are incorporated by reference in this registration statement as of their respective dates:

All reports and other documents filed by the Registrant after the date hereof pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), but prior to the filing of a post-effective amendment which indicates that all securities offered hereby have been sold or which deregisters all securities then remaining unsold, shall be deemed to be incorporated by reference herein and to be part hereof from the date of filing of such reports and documents, except for the documents, or portions thereof, that are “furnished” rather than filed with the Commission.

For the purposes of this registration statement, any statement contained in a document incorporated or deemed to be incorporated by reference herein shall be deemed to be modified or superseded to the extent that a statement contained

herein or in any other subsequently filed document which also is or is deemed to be incorporated by reference herein modifies or supersedes such statement. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this registration statement.

Item 4. Description of Securities.

Not applicable. The class of securities to be offered is registered under Section 12 of the Exchange Act.

Item 5. Interests of Named Experts and Counsel.

Not applicable.

Item 6. Indemnification of Directors and Officers.

Section 102 of the Delaware General Corporation Law (the “DGCL”) permits a corporation to eliminate the personal liability of its directors or its stockholders for monetary damages for a breach of fiduciary duty as a director, except where the director breached his or her duty of loyalty, failed to act in good faith, engaged in intentional misconduct or knowingly violated a law, authorized the payment of a dividend or approved a stock repurchase in violation of Delaware corporate law or obtained an improper personal benefit. The Registrant’s Certificate of Incorporation provides that no director shall be personally liable to the Registrant or its stockholders for monetary damages for any breach of fiduciary duty as a director, notwithstanding any provision of law imposing such liability, except to the extent that the DGCL prohibits the elimination or limitation of liability of directors for breaches of fiduciary duty.

Section 145 of the DGCL provides that a corporation has the power to indemnify a director, officer, employee or agent of the corporation and certain other persons serving at the request of the corporation in related capacities against expenses (including attorneys’ fees), judgments, fines and amounts paid in settlements actually and reasonably incurred by the person in connection with an action, suit or proceeding to which he or she is or is threatened to be made a party by reason of such position, if such person acted in good faith and in a manner he or she reasonably believed to be in or not opposed to the best interests of the corporation, and, in any criminal action or proceeding, had no reasonable cause to believe his or her conduct was unlawful, except that, in the case of actions brought by or in the right of the corporation, no indemnification shall be made with respect to any claim, issue or matter as to which such person shall have been adjudged to be liable to the corporation unless and only to the extent that the Court of Chancery or other adjudicating court determines that, despite the adjudication of liability but in view of all of the circumstances of the case, such person is fairly and reasonably entitled to indemnification for such expenses which the Court of Chancery or such other court shall deem proper.

The Registrant’s Certificate of Incorporation provides that the Registrant will indemnify each person who was or is a party or threatened to be made a party to any threatened, pending or completed action, suit or proceeding, whether civil, criminal, administrative or investigative (other than an action by or in the right of us), by reason of the fact that he or she is or was, or has agreed to become, the Registrant’s director or officer, or is or was serving, or has agreed to serve, at the Registrant’s request as a director, officer, partner, employee or trustee of, or in a similar capacity with, another corporation, partnership, joint venture, trust or other enterprise (all such persons being referred to as an Indemnitee), or by reason of any action alleged to have been taken or omitted in such capacity, against all expenses (including attorneys’ fees), judgments, fines and amounts paid in settlement actually and reasonably incurred in connection with such action, suit or proceeding and any appeal therefrom if such Indemnitee acted in good faith and in a manner he or she reasonably believed to be in, or not opposed to, the Registrant’s best interests, and, with respect to any criminal action or proceeding, he or she had no reasonable cause to believe his or her conduct was unlawful.

The Registrant’s Certificate of Incorporation also provides that the Registrant will indemnify any Indemnitee who was or is a party to an action or suit by or in the right of the Registrant to procure a judgment in the Registrant’s favor by reason of the fact that the Indemnitee is or was, or has agreed to become, the Registrant’s director or officer, or is or was serving, or has agreed to serve, at the Registrant’s request as a director, officer, partner, employee or trustee of, or in a similar capacity with, another corporation, partnership, joint venture, trust or other enterprise, or by reason of any action alleged to have been taken or omitted in such capacity, against all expenses (including attorneys’ fees) and, to the extent permitted by law, amounts paid in settlement actually and reasonably incurred in connection with such action, suit or proceeding, and any appeal therefrom, if the Indemnitee acted in good faith and in a manner he or she reasonably believed to be in, or not opposed to, the Registrant’s best interests, except that no indemnification shall be made with respect to any claim, issue or matter as to which such person shall have been adjudged to be liable to the Registrant, unless a court determines that, despite such adjudication but in view of all of the circumstances, he or she is entitled to indemnification of such expenses. Notwithstanding the foregoing, to the extent that any Indemnitee has been successful, on the merits or otherwise, he or she will be indemnified by the Registrant against all expenses (including attorneys’ fees) actually and reasonably incurred by him or her or on his or her behalf in connection therewith. If the Registrant does not assume the defense, expenses must be advanced to an Indemnitee under certain circumstances.

The Registrant maintains a general liability insurance policy that covers certain liabilities of the Registrant’s directors and officers arising out of claims based on acts or omissions in their capacities as directors or officers.

Insofar as the foregoing provisions permit indemnification of directors, executive officers, or persons controlling the Registrant for liability arising under the Securities Act, the Registrant has been informed that, in the opinion of the SEC, such indemnification is against public policy as expressed in the Securities Act and is therefore unenforceable.

Item 7. Exemption from Registration Claimed.

Not applicable.

Item 8. Exhibits.

* Filed herewith.

Item 9. Undertakings.

(i) to include any prospectus required by Section 10(a)(3) of the Securities Act;

(ii) to reflect in the prospectus any facts or events arising after the effective date of this Registration Statement which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement. Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the Commission pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than 20% change in the maximum aggregate offering price set forth in the “Calculation of Registration Fee” table in the effective registration statement; and

(iii) to include any material information with respect to the plan of distribution not previously disclosed in this Registration Statement or any material change to such information in this Registration Statement;

provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) do not apply if the registration statement is on Form S-8, and the information required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to the Commission by the Registrant pursuant to Section 13 or Section 15(d) of the Exchange Act that are incorporated by reference in the Registration Statement.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8, and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in Houston, Texas, on the 2nd day of April, 2026.

POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below constitutes and appoints Frederick E. Pierce and Mark J. Rosenblum, and each of them, his or her true and lawful attorneys-in-fact and agents, with full power of substitution and resubstitution, to sign any and all amendments (including post-effective amendments) to this registration statement on Form S-8 and to file the same, with all exhibits thereto and other documents in connection therewith, with the Securities and Exchange Commission, granting unto each of said attorneys-in-fact and agents, full power and authority to do and perform each and every act and thing requisite and necessary to be done in connection therewith, as fully to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that each of said attorneys-in-fact and agents, or his or her substitute or substitutes, or any of them, shall do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Act of 1933, this Registration Statement has been signed below by the following persons in the capacities and on the date indicated.

Exhibit 5.1

April 2, 2026

Decoy Therapeutics Inc.

2450 Holcombe Blvd., Suite X

Houston, Texas 77021

Re: Registration Statement on Form S-8

Ladies and Gentlemen:

We have acted as special counsel to Decoy Therapeutics Inc. (formerly known as Salarius Pharmaceuticals, Inc.), a Delaware corporation (the “Company”), in connection with the preparation and filing with the Securities and Exchange Commission (the “Commission”) of a Registration Statement on Form S-8 (the “Registration Statement”) under the Securities Act of 1933, as amended (the “Securities Act”), relating to the issuance by the Company of up to 105,282 shares (the “Shares”) of the Company’s common stock, par value $0.0001 per share (the “Common Stock”), which may be issued pursuant to the Decoy Therapeutics Inc. 2026 Equity Incentive Plan (the “2026 Plan”) and the Decoy Therapeutics Inc. 2020 Equity Incentive Plan (the “2020 Plan” and together with the 2026 Plan, the “Plans”). This opinion is being furnished in connection with the requirements of Item 601(b)(5) of Regulation S-K under the Act, and no opinion is expressed herein as to any matter pertaining to the contents of the Registration Statement or the prospectus forming a part thereof, other than as expressly stated herein with respect to the issuance of the Shares.

In so acting, we have considered such matters of law and of fact, and relied upon, without independent investigation such documents, records, certificates and other information furnished to us as we have deemed appropriate as a basis for our opinions set forth below. In conducting such review, we have assumed, without independent investigation, the genuineness and authenticity of all signatures on original documents, the legal capacity of all natural persons or entities (other than the Company), the authenticity and completeness of all documents submitted to us as originals, the conformity to authentic original documents of all documents submitted to us as copies, and the accuracy of all statements in certificates of public officials and officers of the Company that we reviewed.

The law covered by the opinions expressed in this opinion letter is limited to the General Corporation Law of the State of Delaware (the “DGCL”) as currently in effect. We are not admitted to practice in the State of Delaware and, with respect to the opinion set forth herein, insofar as it relates to any Delaware law, we have limited our review to standard compilations available to us of the DGCL, which we have assumed to be accurate and complete, and we have not reviewed case law. We express no opinion as to any other laws.

This opinion speaks only at and as of its date and is based solely on the facts and circumstances known to us as of such date, and we have no obligation or responsibility to update or supplement this opinion to reflect any facts or circumstances that may hereafter come to our attention or any changes in law that may hereafter occur.

Based upon, subject to and limited by the foregoing, and subject to the assumptions stated and in reliance on statements of fact contained in the documents that we have examined, we are of the opinion that when the Shares shall have been duly registered on the books of the transfer agent and registrar therefor in the name or on behalf of the recipients thereof, and have been issued by the Company for legal consideration in excess of par value in the circumstances contemplated by the Plans, assuming in each case that the individual grants or awards under the Plans are duly authorized by all necessary corporate action and duly granted or awarded and exercised in accordance with the requirements of law and the Plans (and the agreements and awards duly adopted thereunder and in accordance therewith), the issuance and sale of the Shares will have been duly authorized by all necessary corporate action of the Company, and the Shares will be validly issued, fully paid and nonassessable. In rendering the foregoing opinion, we have assumed that the Company will comply with all applicable notice requirements regarding uncertificated shares provided in the DGCL and that at the time of issuance, the number of shares of Common Stock that then remain authorized, unissued, unreserved, and available for issuance will equal or exceed the number of Shares to be issued.

This opinion is for your benefit in connection with the Registration Statement and may be relied upon by you and by persons entitled to rely upon it pursuant to the applicable provisions of the Securities Act. We hereby consent to the filing of this opinion with the Commission as an exhibit to the Registration Statement. In giving such consent, we do not admit that we are within the category of persons whose consent is required by Section 7 of the Securities Act or the rules and regulations promulgated thereunder by the Commission.

Very truly yours,

/s/ Honigman LLP

Honigman LLP

Exhibit 10.2

EQUITY INCENTIVE PLAN

DECOY THERAPEUTICS, INC.

May 25th, 2020

DECOY THERAPEUTICS, INC.

EQUITY INCENTIVE PLAN

ARTICLE 1

PURPOSE

The purpose of this Plan is to assist the Company in attracting, retaining and motivating key employees, officers, directors and consultants of the Company or of a Related Entity who will contribute to the Company’s long-term success by providing them incentives that align their interests with those of the stockholders of the Company.

Awards that may be granted under this Plan include: (a) Options; (b) ISOs; and (c) Restricted Awards.

ARTICLE 2

INTERPRETATION

When used herein, unless the context otherwise requires, the following terms have the following meanings, respectively:

“Award” means any right granted under this Plan, including (a) Options; (b) ISOs; and (c) Restricted Awards;

“Award Agreement” means a written agreement, contract, certificate or other instrument or document evidencing the terms and conditions of an individual Award granted under this Plan which may, in the discretion of the Company, be transmitted electronically to any Participant. Unless specifically stated otherwise, each Award Agreement shall be subject to the terms and conditions of this Plan;

“Awardee” means a Participant who has been granted one or more Awards; “Board” means the board of directors of the Company;

“Cause” shall have the meaning provided in the applicable employment agreement; provided if there is no such definition than Cause shall mean: (1) the Optionee’s willful failure, refusal or willful neglect of or repeated and demonstrated failure to perform the material duties of the Optionee’s position in a competent manner; (2) the commission of any act or any omission by the Optionee that could reasonable be determined by a party to constitute (i) a criminal offence involving fraud, dishonesty misappropriation, embezzlement or similar conduct against the Company or any of its affiliates, or which otherwise adversely impacts the reputation of the Company or (ii) a violation of any applicable securities laws or any rules or regulations thereunder, or any rules of any self-regulatory body in the securities industry or any industry in which the Company operates; (3) the Optionee or any member of the Optionee’s immediate family making personal profit or other material benefit out of or in connection with a transaction or business opportunity with which the Company is involved or otherwise associated or which a reasonable party might determine the Company has an interest or expectancy in, without making disclosure to and receiving the prior written consent of the

Company; (4) the Optionee’s failure to comply with any Company rules or policies of a material nature; (5) any actions or omissions on the part of the Optionee constituting gross misconduct or gross negligence with respect to business matters, in each case, if determined reasonably, on an informed basis and in good faith by the Board or, if so delegated by the Board, the management of the Company.

“Change in Control” means:

provided that, for greater certainty, unless otherwise determined by the Board, the following events shall not constitute a “Change in Control”: (i) an amalgamation, merger or consolidation of the Company with or into a Related Entity; (ii) a transaction undertaken solely for the purpose of changing the Company’s place of domicile or jurisdiction of incorporation; (iii) an equity financing of the Company; or (iv) an Initial Public Offering.

The Board may adopt by a 70% majority vote of the “continuing directors” a resolution to the effect that an event described in clauses (i) or (ii) shall not constitute a “change of control.” For purposes of this clause, “continuing directors” means those members of the Board who either were directors at the beginning of the consecutive twelve month period prior to such event or were elected by or on the nomination or recommendation of at least a 70% majority of the then-existing “continuing directors.”

“Change in Control Price” means the amount payable in respect of each Common Share upon the occurrence of the Change in Control; provided that in the absence of an established amount payable in connection with the Change in Control, the “Change in Control Price” shall be determined in good faith by the Board and such determination shall be conclusive and binding on all persons;

“Code” means the United States Internal Revenue Code of 1986, as amended;

“Common Shares” means the shares of Common, no par value per share, of the Company; “Company” means Decoy Therapeutics, Inc., a Delaware corporation;

“Consultant Participant” means an individual or a consultant company or such individual or consultant company’s designated affiliate, other than an Employee Participant, a Director Participant or an Executive Participant, that:

For the purposes of this definition, “consultant company” means, with respect to an individual consultant, either (i) a company of which the individual consultant is an employee or stockholder; or (ii) a partnership of which the individual consultant is an employee or partner;

“Date of Grant” means, for any Award, the date specified by the Board at the time it grants the Award (provided, however, that such date shall not be prior to the date the Board acts to grant the Award) or, if no such date is specified, the date upon which the Award was granted;

“Director” means a member of the Board or a member of the board of directors of a Related Entity;

“Director Participant” means a Director, who is not an officer or employee of the Company or of a Related Entity;

“Disabled” or “Disability” means the permanent and total incapacity of an Optionee as determined in accordance with procedures established by the Board for purposes of this Plan;

“Dividend Equivalents” has the meaning set forth in Section 5.2(b);

“Employee Participant” means a current employee (other than an Executive Participant or a Consultant Participant) of the Company or of a Related Entity;

“Executive Participant” means an officer of the Company or of a Related Entity;

“Exercise Notice” means a notice in writing, in the form set out in Schedule B, signed by an Optionee and stating the Optionee’s intention to exercise a particular Option;

“Exercise Period” means the period of time during which an Option granted under this Plan may be exercised in accordance with this Plan;

“Exercise Price” means the price at which an Option Share may be purchased pursuant to the exercise of an Option which shall be no less than the Fair Market Value of the underlying share on the Date of Grant;

“Fair Market Value” means, as of any date, the value of a Common Share as follows: (i) if the Common Share is listed on any established stock exchange or a national market system, the “Fair Market Value” shall be the closing price of a Common Share (or if no sales were reported, the closing price on the date immediately preceding such date) as quoted on such exchange or system on the day of determination; or (ii) in the absence of an established market for the Common Share, then the fair market value shall be determined by the Board in good faith after taking into consideration all factors which it deems appropriate, including, without limitation, Sections 409A and 422 of the Code.

“Individual Optionee” means an Optionee who is an individual;

“Initial Public Offering” means any initial public offering of the Company’s securities resulting in the Company’s securities being publicly traded on a recognized North American stock exchange (including, for greater certainty, the NASDAQ National Market);

“ISO” has the meaning set forth in Section 4.11;

“Option” means a right to purchase Common Shares under this Plan that is non-assignable and non-transferable unless otherwise approved by the Board;

“Optionee” means a Participant who has been granted one or more Options;

“Option Shares” means Common Shares that will be issued by the Company upon the exercise of outstanding Options;

“Participant” means an Employee Participant, a Director Participant, an Executive Participant or a Consultant Participant;

“person” includes an individual, sole proprietorship, partnership, unincorporated association, unincorporated syndicate, unincorporated organization, trust, body corporate, limited liability company, and a natural person in his or her capacity as trustee, executor, administrator or other legal representative;

“Plan” means this Equity Incentive Plan, as may be amended or restated from time to time;

“Related Entity” means a person that controls or is controlled by the Company or that is controlled by the same person that controls the Company;

“Restricted Award” means any Award granted pursuant to Article 5;

“Restricted Period” has the meaning set forth in Section 5.1;

“Restricted Shares” has the meaning set forth in Section 5.1;

“Restricted Share Units” has the meaning set forth in Section 5.1;

“Sale of the Company” means either: (i) a transaction or series of related transactions in which a person, or a group of related persons, acquires from stockholders, shares of capital stock of the Company representing more than 50% of the outstanding voting power of the Company; or (ii) a Deemed Liquidation Event;

“Stockholders Agreement” means: the Stockholders Agreement between the Company and its stockholders dated May 25th, 2020, any other stockholders agreement between the Company and its stockholders, as may be in effect from time to time, in each case, as may be amended, restated or replaced from time to time;

“Termination Date” means:

“Vesting Commencement Date” means, for any Option, the date for vesting of such Option to commence, as specified by the Board at the time it grants such Option, or, if no such date is specified, the Date of Grant; and

ARTICLE 3

PLAN ADMINISTRATION

This Plan will be administered by the Board and the Board has sole and complete authority, in its discretion, to:

The Board’s determinations and actions within its authority under this Plan are conclusive and binding on the Company and all other persons.

All Participants are eligible to participate in this Plan, subject to Sections 4.6(b) and 4.7(g). Eligibility to participate does not confer upon any Participant any right to be granted Awards pursuant to this Plan. The extent to which any Participant is entitled to be granted Awards pursuant to this Plan will be determined in the discretion of the Board.

All Awards under this Plan will be evidenced by Award Agreements. Such Award Agreements will be subject to the applicable provisions of this Plan and will contain such provisions as are required by this Plan and any other provisions that the Board may direct. The Board shall authorize and empower any director or officer of the Company to execute and deliver, for and on behalf of the Company, an Award Agreement to each Participant.

Each Awardee shall be required, at the time of exercising an Option, upon receiving Restricted Shares or upon receiving Common Shares in connection with the settlement of a Restricted Share Unit, to sign and deliver an adoption agreement or counterpart and acknowledgement to the Stockholders Agreement then in effect and any other agreement that the Company requires a holder of Common Shares to sign (to the extent that such agreements exist and such Awardee is not already a party to such agreements), in form and substance satisfactory to the Company. Each Awardee acknowledges that the Stockholders Agreements restrict transfers of Common Shares.

ARTICLE 4

OPTIONS

The Board may, from time to time, subject to the provisions of this Plan and such other terms and conditions as the Board may prescribe, grant Options to any Participant pursuant to an Award Agreement. An Award Agreement evidencing a grant of Options shall be substantially in the form attached as Schedule A.

Subject to any accelerated termination as set forth in this Plan, each Option, unless otherwise specified by the Board, expires on the 10th anniversary of the Vesting Commencement Date, provided that in no event will the Exercise Period of an Option exceed 10 years.

provided that in no event will an Option be exercisable after the expiration or termination of such Option.

Unless otherwise specified by the Board at the time of granting an Option:

Subject to Section 4.8, or unless otherwise specified by the Board at the time of granting an Option, if an Individual Optionee dies or becomes Disabled while the Individual Optionee is an employee, director or officer of the Company or a Related Entity then:

Subject to Section 4.8 or unless otherwise specified by the Board at the time of granting an Option:

Notwithstanding the provisions of Sections 4.5(a) and 4.7, the Board may, in its discretion, at any time prior to or following the events contemplated in such sections, permit the exercise of any or all Options held by the Optionee, in the manner and on the terms authorized by the Board, provided that the Board will not, in any case, authorize the exercise of an Option pursuant to this Section 4.8 beyond the expiration of the Exercise Period of the particular Option.

Notwithstanding anything else in this Plan or any Award Agreement, the Board may, in connection with a Change in Control and at its sole discretion and without the consent of any Optionee, take such

steps as are necessary or desirable with respect to all outstanding Options that are in the best interests of the Company, including:

Without limiting Section 3.5, each Optionee will, when requested by the Company, sign and deliver all such documents relating to the granting or exercise of Options which the Company deems necessary or desirable.

The following provisions shall apply, in addition to the other provisions of this Plan which are not inconsistent therewith, to Options intended to qualify as “incentive stock options” (each, for purposes of this Section 4.11, an “ISO”) under Section 422 of the Code:

Subject to Section 4.5(a), applicable law and the rules and policies of any stock exchange on which the Common Shares are listed, if applicable, Options granted under this Plan may only be exercised during the lifetime of the Individual Optionee by such Individual Optionee personally, except as otherwise provided in Section 4.6. Except to the extent permitted by the Board, no assignment or transfer of Options, whether voluntary, involuntary, by operation of law or otherwise, vests any interest or right in such Options whatsoever in any assignee or transferee and immediately upon any assignment or transfer, or any attempt to make the same, such Awards will terminate and be of no further force or effect.

ARTICLE 5

RESTRICTED AWARDS

A Restricted Award is an Award of Common Shares (“Restricted Shares”) or hypothetical Common Share units (“Restricted Share Units”) having a value equal to the Fair Market Value of an identical number of Common Shares, which may, but need not, provide that such Restricted Award may not be sold, assigned, transferred or otherwise disposed of, pledged or hypothecated as collateral for a loan or as security for the performance of any obligation or for any other purpose for such period (the “Restricted Period”) as the Board shall determine. Each Restricted Award so granted shall be subject to the conditions set forth in this Article 5, and to such other conditions not inconsistent with this Plan as may be reflected in the applicable Award Agreement.

in each case, prior to the fourth anniversary of the Date of Grant, then that number of Restricted Shares or Restricted Share Units subject to the Restricted Award as is equal to:

Each certificate representing Restricted Shares awarded under this Plan shall bear a legend in such form as the Company deems appropriate.

ARTICLE 6

SHARE CAPITAL ADJUSTMENTS

The existence of any Awards does not affect in any way the right or power of the Company or its stockholders to make, authorize or determine any adjustment, recapitalization, reorganization or any other change in the Company’s capital structure or its business, or any amalgamation, arrangement, combination, merger or consolidation involving the Company, to create or issue any bonds, debentures, Common Shares or other securities of the Company or to determine the rights and conditions attaching thereto, to effect the dissolution or liquidation of the Company or any sale or transfer of all or any part of its assets or business, or to effect any other corporate act or proceeding, whether of a similar

character or otherwise, whether or not any such action referred to in this section would have an adverse effect on this Plan or any Award pursuant to this Plan.

Should the Company effect a subdivision or consolidation of Common Shares or any similar capital reorganization or a payment of a share dividend (other than a share dividend that is in lieu of a cash dividend), or should any other change be made in the capitalization of the Company that, in the opinion of the Board, would warrant the replacement or amendment of any existing Awards in order to adjust: (a) the number of Common Shares that may be acquired pursuant to any outstanding Awards; and/or (b) in the case of Options, the Exercise Price of any outstanding Options in order to preserve proportionately the rights and obligations of the Optionees, the Board will authorize such steps to be taken as may be equitable and appropriate to that end.

In the event of an amalgamation, arrangement, combination, merger or other reorganization involving the Company by exchange of Common Shares, by sale or lease of assets or otherwise, that, in the opinion of the Board, warrants the replacement or amendment of any existing Awards in order to adjust: (a) the number of Common Shares that may be acquired pursuant to any outstanding Awards; and/or (b) in the case of Options, the Exercise Price of any outstanding Options in order to preserve proportionately the rights and obligations of the Optionees, the Board will authorize such steps to be taken as may be equitable and appropriate to that end.

Where the Board determines that the steps provided in Sections 6.2 and 6.3 would not preserve proportionately the rights and obligations of the Awardees in the circumstances or otherwise determines that it is appropriate, the Board may permit the immediate exercise of any outstanding Awards that are not otherwise exercisable.

Except as expressly provided in this Article 6, neither the issue by the Company of shares of any class of capital stock of the Company or by the Company or a Related Entity of securities convertible into or exchangeable for shares of any class of capital stock of the Company, nor the conversion or exchange of such shares or securities, affects (and no adjustment by reason thereof is to be made with respect to): (a) the number of Common Shares that may be acquired pursuant to any outstanding Awards; or (b) in the case of Options, the Exercise Price of any outstanding Options.

No fractional Common Shares will be issued on the exercise of an Award. Accordingly, if, as a result of any adjustment under Sections 6.2 to 6.4 inclusive, an Awardee would become entitled to a fractional Common Share, the Awardee has the right to acquire only the adjusted number of full Common Shares and no payment or other adjustment will be made with respect to the fractional Common Shares so disregarded.

This Plan and each Award are subject to the requirement that if at any time the Board determines that the listing, registration or qualification of the Common Shares subject to such Award upon any securities exchange or under any provincial or federal law, or the consent or approval of any governmental body, securities exchange or of the holders of the Common Shares generally, is necessary or desirable, as a condition of, or in connection with, the granting of such Award or the issue or purchase of Common Shares thereunder, no such Award may be granted or exercised in whole or in part unless such listing, registration, qualification, consent or approval has been effected or obtained free of any conditions not acceptable to the Board. The Awardees shall, to the extent applicable, cooperate with the Company in relation to such listing, registration, qualification, consent or other approval and shall have no claim or cause of action against the Company or any of its officers or directors as a result of any failure by the Company to obtain or to take any steps to obtain any such registration, qualification or approval.

ARTICLE 7

MISCELLANEOUS PROVISIONS

The Company is not obligated to grant any Awards, issue any Common Shares or other securities, make any payments or take any other action if, in the opinion of the Board, in its sole discretion, such action would constitute a violation by an Awardee, the Company or a Related Entity of any provision of any applicable statutory or regulatory enactment of any government or government agency.

Except as otherwise provided in this Plan, Awards previously granted under this Plan, whether or not then exercisable, are not affected by any change in the relationship between, or ownership of, the Company and a Related Entity. For greater certainty, all Awards remain valid and, in the case of Options, exercisable, in accordance with the terms and conditions of this Plan and are not affected by reason only that, at any time, a Related Entity ceases to be a Related Entity.

As a condition of and prior to participation in this Plan, each Awardee authorizes the Company to withhold from any amount otherwise payable to the Awardee any amounts required by any taxing authority to be withheld for taxes of any kind as a consequence of the Awardee’s participation in this Plan or issuance of Common Shares. The Company may, prior to and as a condition of issuing any Common Shares in such circumstances, require the Awardee to pay to the Company in cash or such other consideration as the Board, in its discretion, may accept, such amount as the Company is obliged to remit in accordance with applicable laws in respect of any such issuance of Common Shares or payment or crediting of such amount. The Company shall also have the right, in its sole discretion, to satisfy any such liability for withholding or other required deduction amounts by requiring the Awardee to complete a sale in respect of such number of Common Shares that have been issued and would otherwise be delivered to the Awardee under this Plan, and any amount payable from such sale will first be paid to the Company to satisfy any liability for withholding. The Company may require an Awardee, as a condition of participation in this Plan, to pay or reimburse the Company for any cost incurred by the Company as a result of the participation by the Awardee in this Plan.

Subject to the discretion of the Board, an Awardee that has been issued Common Shares pursuant to an Award granted under this Plan shall, by acceptance of such Common Shares, be deemed to have waived any rights such stockholder would otherwise have to receive financial statements of the Company.

No Participant has any claim or right to be granted an Award (including an Award granted in substitution for any Award that has expired pursuant to the terms of this Plan). No Optionee or Awardee for Restricted Share Units has any rights as a stockholder of the Company in respect of Common Shares issuable pursuant to any Award until the allotment and issuance to the Optionee or the Awardee for Restricted Share Units of certificates representing such Common Shares in accordance with this Plan and the applicable Award Agreement representing such Option or Restricted Share Units, as the case may be.

The Board may terminate this Plan at any time without stockholder approval. Notwithstanding the foregoing, subject to the discretion of the Board, the termination of this Plan shall have no effect on outstanding Awards, which shall continue in effect in accordance with their terms and conditions and the terms and conditions of this Plan.

The Board may make changes to the terms of any granted Awards or this Plan to the extent necessary or desirable to comply with any rules, regulations or policies of any stock exchange on which the Common Shares may be listed following an Initial Public Offering.

Every Director will at all times be indemnified and saved harmless by the Company from and against all costs, charges and expenses whatsoever, including any income tax liability arising from any such indemnification, that such Director may sustain or incur by reason of any action, suit or proceeding, taken or threatened against the Director, otherwise than by the Company or a Related Entity, for or in respect of any act done or omitted by the Director in respect of this Plan, such costs, charges and expenses to include any amount paid to settle such action, suit or proceeding or in satisfaction of any judgment rendered therein.

The participation of any Participant in this Plan is entirely voluntary and not obligatory and shall not be interpreted as conferring upon such Participant any rights or privileges other than those rights and privileges expressly provided in this Plan. In particular, participation in this Plan does not constitute a condition of employment or service nor a commitment on the part of the Company or any Related Entity to ensure the continued employment or service of such Participant. This Plan does not provide any guarantee against any loss which may result from fluctuations in the market value of the Common Shares. The Company does not assume responsibility for the personal income or other tax consequences for the Participants and they are advised to consult with their own tax advisors.

The Board may, without notice, at any time or from time to time, amend this Plan or any provisions hereof in such respects as it, in its sole discretion, determines appropriate; provided that no such amendment shall have any effect with respect to all Awards outstanding as at the date of such amendment without the prior consent of the Awardees holding Awards that represent at least a majority of the Common Shares that are subject to the then outstanding Awards; provided that if any such amendment impairs an Awardee’s rights or increases an Awardee’s obligations under such Awardee’s Award or creates or increases an Awardee’s income tax liability with respect to an Award, in each case, in a manner that would materially and adversely affect such Awardee disproportionately more than any other Awardee, such amendment shall also be subject to such Awardee’s consent.

Nothing contained in this Plan or in an Award shall be construed so as to prevent the Company from taking corporate action which is deemed by the Company to be appropriate or in its best interest, whether or not such action would have an adverse effect on this Plan or any Award, including, with respect to an Award previously granted, any adjustments to the Exercise Price that is not below the Fair Market Value of the underlying shares at grant, Exercise Period or number of Common Shares subject to the Award, provided that any such adjustment is required by any securities exchange or applicable securities laws, and does not trigger penalty tax under Section 409A of the Internal Revenue Code of 1986, as amended.

All written notices to be given by the Awardees to the Company shall be delivered personally or by registered mail, postage prepaid, addressed as follows:

Decoy Therapeutics, Inc.

29 Bigelow Street, #3

Cambridge, MA 02139

Attention: Secretary

E-mail:

Any notice given by the Awardee pursuant to the terms of an Award shall not be effective until actually received by the Company at the above address.

DATED May 25th, 2020.

[Signature Page Follows]

[SIGNATURE PAGE TO THE EQUITY INCENTIVE PLAN]

APPENDIX A

TO

DECOY THERAPEUTICS, INC. EQUITY INCENTIVE PLAN

(for California residents only, to the extent required by

California Corporations Code Section 25102(o))

This Appendix A to the Decoy Therapeutics, Inc. Equity Incentive Plan (the “Plan”) shall apply only to the Participants who are residents of the State of California and who are receiving an Award under the Plan in reliance on California Corporations Code Section 25102(o) only. Capitalized terms contained herein shall have the same meanings given to them in the Plan, unless otherwise provided by this Appendix A. Notwithstanding any provisions contained in the Plan to the contrary and to the extent required by applicable laws, the following terms shall apply to all Awards granted to residents of the State of California, until the earlier to occur of (i) the Initial Public Offering, (ii) such time as the Committee amends this Appendix A or (iii) at such time as the Committee otherwise provides.

SCHEDULE A

Form of Award Agreement

[•11

Dear [•1:

Congratulations!

Decoy Therapeutics, Inc. (the “Company”) grants to you an option (this “Option”) to purchase, in accordance with and subject to the terms, conditions and restrictions of this Award Agreement (which are attached to this Award Agreement as Appendix I) and the provisions of the Equity Incentive Plan of the Company dated May 25th, 2020 (the “Plan”), the number and type of the Company’s Common Shares (the “Common Shares”) at an exercise price per share set forth below:

1 Insert Date of Grant

If you wish to accept this Option, please print your name and sign and date this Award Agreement, as set out below.

I have read the foregoing Award Agreement and accept this Option to purchase Common Shares in accordance with and subject to the terms and conditions of this Award Agreement and the Plan. I understand that I may review the complete text of the Plan by contacting the Chief Executive Officer of the Company. I agree to be bound by the terms and conditions of the Plan governing this Option.

APPENDIX I TO AWARD AGREEMENT

GENERAL TERMS AND CONDITIONS

In the event of any adjustment of, changes in or additions to the Common Shares, any new, substituted or additional interests or securities which are by reason of such adjustment, change or addition distributed with respect to any Common Shares subject to the Market Stand-Off, or into which such Common Shares thereby become convertible, shall immediately be subject to the Market Stand-Off. In order to enforce the Market Stand-Off, the Company may impose stop-transfer instructions with respect to the Common Shares acquired under this Award Agreement until the end of the applicable stand-off period. The Company’s underwriters shall be beneficiaries of the agreement set forth in this Section 13(b). This Section 13(b) shall not apply to Common Shares that are registered in a public offering under the Securities Act.

“THE SHARES OF DECOY THERAPEUTICS, INC. (“SHARES”) HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE “SECURITIES ACT”), THE SECURITIES LAWS OF ANY STATE OR ANY OTHER APPLICABLE SECURITIES LAWS, AND HAVE BEEN ISSUED IN RELIANCE UPON EXEMPTIONS FROM THE REGISTRATION REQUIREMENTS OF THE SECURITIES ACT AND SUCH LAWS. SUCH SHARES MUST BE ACQUIRED FOR INVESTMENT ONLYAND NOT WITH A VIEW TO, OR IN CONNECTION WITH, THE SALE OR DISTRIBUTION THEREO AND MAY NOT BE OFFERED FOR SALE, PLEDGED, HYPOTHECATED, MORTGAGED, ENCUMBERED, DISPOSED, SOLD, ASSIGNED, EXCHANGED, DEVISED, BEQUESTED, OR OTHERWISE TRANSFERRED AT ANY TIME EXCEPT IN COMPLIANCE WITH (A) THE SECURITIES ACT, (B) ANY APPLICABLE STATE SECURITIES LAWS, (C) ANY OTHER APPLICABLE SECURITIES LAWS, AND (D) THE TERMS AND CONDITIONS OF THE STOCKHOLDERS AGREEMENT OF DECOY THERAPEUTICS, INC., DATED MAY 25th, 2020, AS MAY BE AMENDED, A COPY OF WHICH IS ON FILE IN THE OFFICE OF THE SECRETARY OF THE CORPORATION AND MAY BE REVIEWED UPON REQUEST, AND, IN EACH CASE AN OPINION OF COUNSEL IN A FORM SATISFACTORY TO THE COMPANY THAT SUCH REQUIREMENTS HAVE BEEN COMPLIED WITH. IN ADDITION, HEDGING TRANSACTIONS INVOLVING THE SHARES MAY NOT BE CONDUCTED UNLESS IN COMPLIANCE WITH THE SECURITIES ACT”

In the event that any non-qualified deferred compensation (as determined under Section 409A) is payable upon your Separation from Service under this Award Agreement, or any other plan in which you participate, then notwithstanding anything else in the applicable agreement or plan, if you are a Specified Employee, no amount shall be payable prior to the six months from the date that you experience a Separation from Service.

For the purposes of this Section 14, “Separation from Service” shall have the meaning given thereto under Section 409A and the regulations and authority thereunder; and “Specified Employee” shall have the meaning set forth in Section 409A and the regulations and authority thereunder and shall be determined in accordance with the Company’s regular process for the identification of “Specified Employees”.

SCHEDULE B

Form of Exercise Notice – Options

I, , hereby exercise the option (print name) to purchase Common Shares (each, a “Common Share”) of Decoy Therapeutics, Inc. (the “Company”) at a purchase price of $ per Common Share. This Exercise Notice is delivered in respect of the option to purchase Common Shares (the “Option”) that was granted to me on pursuant to the Award Agreement entered into between the Company and me.

[In connection with the foregoing, I enclose cash, a certified check, bank draft or money order payable to the Company in the amount of $ as full payment for the Common Shares to be received upon exercise of the Option.

In connection with the foregoing (check one):

Exhibit 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in the Registration Statement (Form S-8) pertaining to the Decoy Therapeutics Inc. 2026 Equity Incentive Plan and the Decoy Therapeutics Inc. 2020 Equity Incentive Plan of our report dated March 31, 2026, with respect to the consolidated financial statements of Decoy Therapeutics Inc. included in its Annual Report (Form 10-K) for the year ended December 31, 2025, filed with the Securities and Exchange Commission.

/s/ Ernst & Young LLP

Houston, Texas

April 2, 2026