As filed with the Securities and Exchange Commission on November 13, 2026

Registration No. 333-167675

333-191074

333-206323

333-215453

333-218632

333-222259

333-228811

333-235499

333-251144

333-260278

333-267776

333-276951

333-280208

333-291324

UNITED STATES SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

POST-EFFECTIVE AMENDMENT NO. 1 TO

FORM S-8

REGISTRATION STATEMENTS

333-167675, 333-191074, 333-206323, 333-215453, 333-218632, 333-222259, 333-228811,

333-235499, 333-251144, 333-260278, 333-267776, 333-276951, 333-280208, and 333-291324

UNDER THE SECURITIES ACT OF 1933

Curis, Inc.

(Exact Name of Registrant as Specified in Its Charter)

Fifth Amended and Restated 2010 Stock Incentive Plan, as amended

Inducement Awards Granted Pursuant to Nasdaq Stock Market Rule 5635(c)(4)

2026 Incentive Plan

(Full Title of the Plan)

James E. Dentzer

President and Chief Executive Officer

128 Spring Street, Building C – Suite 500

Lexington, MA 02421

(Name and Address of Agent For Service)

(617) 503-6500

(Telephone Number, Including Area Code, of Agent For Service)

with a copy to:

Peter N. Handrinos

Latham & Watkins LLP

200 Clarendon Street

Boston, MA 02116

(617) 948-6000

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

Curis, Inc. (the “Company”) has previously filed registration statements on Form S-8 (File Nos. 333-167675, 333-191074, 333-206323, 333-215453, 333-218632, 333-222259, 333-228811, 333-235499, 333-251144, 333-260278, 333-267776, 333-276951, 333-280208, and 333-291324) (the “Registration Statements”) to register shares of common stock, par value $0.01 per share (“Common Stock”), of the Company, as adjusted for reverse stock splits, available for issuance under the Company’s Fifth Amended and Restated 2010 Stock Incentive Plan, as amended (the “2010 Plan”), and shares of Common Stock issuable pursuant to awards granted under the inducement grant exception under Nasdaq Stock Market Rule 5635(c)(4) (the “Inducement Awards”).

On March 17, 2026 (the “Effective Date”), the stockholders of the Company approved the Company’s 2026 Incentive Plan (the “2026 Plan”). Under the terms of the 2026 Plan: (i) as of the Effective Date, no new awards may be granted under the 2010 Plan, however the terms and conditions of the 2010 Plan will continue to govern any outstanding awards granted thereunder prior to the Effective Date (together with the Inducement Awards, the “Outstanding Awards”); (ii) the number of shares of Common Stock reserved for issuance under the 2010 Plan that remained available for grant under the 2010 Plan as of the Effective Date and the Outstanding Awards that were outstanding as of the Effective Date and which awards expire, terminate or are otherwise surrendered, cancelled, forfeited or repurchased by the Company at their original issuance price pursuant to a contractual repurchase right, will be available for issuance under the 2026 Plan and subject to the terms of the 2026 Plan.

Accordingly, pursuant to the undertaking in Item 512(a)(1)(iii) of Regulation S-K that the Company disclose a material change in the plan of distribution as it was originally disclosed in the Registration Statements and in accordance with Securities Act Forms Corporation Finance Interpretation 126.43, the Company is filing this Post-Effective Amendment to the Registration Statements to reflect that, as of the Effective Date, except to the extent of the number of shares of Common Stock issuable under then Outstanding Awards, the shares of Common Stock available for issuance under such registration statements will no longer be issued under the 2010 Plan or pursuant to the Inducement Awards and may instead be issued under the 2026 Plan. The maximum number of shares of Common Stock previously registered under the Registration Statements that were available for issuance under the 2010 Plan and under the Inducement Grants was 173,744 shares, as adjusted to reflect the reverse stock splits of the Common Stock previously effected by the Company and will be available for issuance under the 2026 Plan. No additional securities are being registered by this Post-Effective Amendment.

PART I

INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

Item 1. Plan Information

Not required to be filed with this Post-Effective Amendment to Registration Statements.

Item 2. Registrant Information and Employee Plan Annual Information

Not required to be filed with this Post-Effective Amendment to Registration Statements.

PART II

INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

DISCLOSURE OF CERTAIN FINANCIAL DATA REFLECTING REVERSE STOCK SPLIT

The following selected financial data has been derived from our audited financial statements in Curis’s Annual Report on Form 10-K for the year ended December 31, 2025 filed with the Commission on March 24, 2026 and our Quarterly Report on Form 10-Q for the period ended March 31, 2026 filed with the Commission on May 13, 2026, as adjusted to reflect the 1-for-20 reverse stock split effected on July 2, 2026 for all periods presented. Our historical results are not indicative of the results that may be expected in the future.

AS REPORTED (in thousands, except share and per share amounts)    

AS ADJUSTED (in thousands, except share and per share amounts)    

Item 3. Incorporation of Documents by Reference.

The Registrant is subject to the informational and reporting requirements of Sections 13(a), 14 and 15(d) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and in accordance therewith files reports, proxy statements and other information with the Securities and Exchange Commission (the “Commission”). The following documents and portions thereof, only to the extent they have been filed (and not furnished) by the Registrant with the Commission, are incorporated in this Post-Effective Amendment to Registration Statements by reference and shall be deemed to be a part hereof:

In addition, all documents subsequently filed (and not furnished) by the Registrant pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act, prior to the filing of a post-effective amendment to this Post-Effective Amendment to Registration Statements 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 in this Post-Effective Amendment to Registration Statements and to be part hereof from their respective dates of filing (such documents and the documents listed above (other than any document furnished to the Commission), being hereinafter referred to as “Incorporated Documents”). Any statement contained in a document incorporated or deemed to be incorporated by reference herein shall be deemed to be modified or superseded for the purposes of this Post-Effective Amendment to Registration Statements 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 statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this Post-Effective Amendment to Registration Statements.

This Post-Effective Amendment to Registration Statements may contain information that updates, modifies or is contrary to information in one or more of the Incorporated Documents. You should not assume that the information in this Post-Effective Amendment to Registration Statements is accurate as of any date other than the date of this Post-Effective Amendment to Registration Statements or the date of the Incorporated Document.

Item 4. Description of Securities.

Not applicable.

Item 5. Interests of Named Experts and Counsel.

Not applicable.

Item 6. Indemnification of Directors and Officers.

The following summary is qualified in its entirety by reference to the complete Delaware General Corporation Law, or the DGCL, and the Registrant’s certificate of incorporation and by-laws.

Section 145 of the DGCL provides, generally, that a corporation shall have the power to indemnify any person who was or is a party or is threatened to be made a party to any threatened, pending or completed action, suit or proceeding (except actions by or in the right of the corporation) by reason of the fact that such person is or was a director, officer, employee or agent of the corporation against all expenses, judgments, fines and amounts paid in settlement actually and reasonably incurred by such person in connection with such action, suit or proceeding if such person acted in good faith and in a manner such person reasonably believed to be in or not opposed to the best interests of the corporation and, with respect to any criminal action or proceeding, had no reasonable cause to believe his or her conduct was unlawful. A corporation may similarly indemnify such person for expenses actually and reasonably incurred by such person in connection with the defense or settlement of any action or suit by or in the right of the corporation, provided that 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 the case of claims, issues and matters as to which such person shall have been adjudged liable to the corporation, provided that a court shall have determined, upon application, 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 indemnity for such expenses which such court shall deem proper.

Section 102(b)(7) of the DGCL provides, generally, that a corporation’s certificate of incorporation may contain a provision eliminating or limiting the personal liability of a director or officer to the corporation or its shareholders for monetary damages for breach of fiduciary duty as a director or officer, provided that such provision may not eliminate or limit the liability of (i) a director or officer for any breach of the director’s or officer’s duty of loyalty to the corporation or its shareholders, (ii) a director or officer for acts or omissions not in good faith or which involve intentional misconduct or a knowing violation of law, (iii) a director under section 174 of the DGCL, (iv) a director or officer for any transaction from which the director or officer derived an improper personal benefit, or (v) an officer in any action by or in the right of the corporation. No such provision may eliminate or limit the liability of a director or officer for any act or omission occurring prior to the date when such provision became effective.

Article Sixth of the Registrant’s certificate of incorporation provides that no director shall be personally liable to the Registrant or any of its stockholders for any monetary damages for any breach of fiduciary duty as a director of the Registrant, except to the extent that the DGCL prohibits the elimination or limitation of liability of directors for breach of fiduciary duty.

Article Eighth of the Registrant’s certificate of incorporation provides, in general, that the Registrant shall indemnify each person who was or is a party or is 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 the Registrant), by reason of the fact that such person is or was, or has agreed to become, a director or officer of the Registrant, or is or was serving or has agreed to serve, at the request of the Registrant, as a director, officer or trustee of, or in a similar capacity with, another corporation (including any partially or wholly owned subsidiary of the Registrant), partnership, joint venture, trust or other enterprise (including any employee benefit plan), against expenses (including attorneys’ fees), judgments, fines and amounts paid in settlement actually and reasonably incurred in connection with any such action, suit or proceeding to the maximum extent permitted by the DGCL. The foregoing right of indemnification is in no way exclusive of any other rights of indemnification to which any such director or officer may be entitled, under any by-law, agreement, vote of directors or stockholders or otherwise.

In addition to the indemnification provided by the Registrant’s certificate of incorporation and under the DGCL, the Registrant has entered into indemnification agreements with its executive officers and directors. The indemnification agreements provide that each such person:

Notwithstanding the foregoing, to the extent that an officer or director has been successful, on the merits or otherwise, he or she is required to be indemnified by the Registrant against all expenses (including attorneys’ fees) incurred in connection with defending any proceeding to the extent that the Registrant does not assume the defense of such proceeding. Expenses shall be advanced to an officer or director, provided that he or she undertakes to repay the amount advanced if it is ultimately determined that he or she is not entitled to indemnification for such expenses.

Indemnification is required to be made unless the Registrant determines that the applicable standard of conduct required for indemnification has not been met. As a condition precedent to the right of indemnification, the officer or director must give the Registrant notice of the action for which indemnity is sought and the Registrant has the right to participate in such action or assume the defense thereof.

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

Item 7. Exemption from Registration Claimed.

Not applicable.

Item 8. Exhibits.

*Filed herewith.

Item 9. Undertakings.

Provided, however, that paragraphs (a)(1)(A) and (a)(1)(B) do not apply if 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 this 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 the City of Lexington, Commonwealth of Massachusetts, on November 13, 2026.

SIGNATURES AND POWER OF ATTORNEY

We, the undersigned officers and directors of Curis, Inc., hereby severally constitute and appoint James E. Dentzer and Diantha Duvall and each of them singly, our true and lawful attorneys with full power to them, and to each of them singly, to sign for us and in our names in the capacities indicated below the Post-Effective Amendment to Registration Statements on Form S-8 filed herewith and any and all subsequent amendments to said Post-Effective Amendment to Registration Statements and generally to do all such things in our names and on our behalf in our capacities as officers and directors to enable Curis, Inc. to comply with the provisions of the Securities Act of 1933, as amended, and all requirements of the Securities and Exchange Commission, hereby ratifying and confirming our signatures as they may be signed by our said attorneys, or any of them, to said Post-Effective Amendment to Registration Statements and any and all amendments thereto.

Pursuant to the requirements of the Securities Act of 1933, as amended, this Post-Effective Amendment to Registration Statements has been signed by the following persons in the capacities and on the dates indicated.

ATTACHMENTS / EXHIBITS

EXHIBIT 5.1

EXHIBIT 23.2