CURIS INC

S-11 cris-sx1august2026.htm S-1

As filed with the U.S. Securities and Exchange Commission on August 10, 2026

Registration No. 333-

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-1

REGISTRATION STATEMENT

UNDER THE SECURITIES ACT OF 1933

CURIS, INC.

(Exact name of registrant as specified in its charter)

128 Spring Street, Building C – Suite 500

(Address, Including Zip Code, and Telephone Number, Including Area Code, of Registrant’s Principal Executive Offices)

James E. Dentzer

President and Chief Executive Officer

Curis, Inc.

128 Spring Street, Building C – Suite 500

(Name, Address, Including Zip Code, and Telephone Number, Including Area Code, of Agent for Service)

Copies to:

Approximate date of commencement of proposed sale to the public: From time to time after this registration statement becomes effective.

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, check the following box.¨

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.¨

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.¨

If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, 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.¨

The Registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the Registrant shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until the Registration Statement shall become effective on such date as the Commission acting pursuant to said Section 8(a), may determine.

The information in this prospectus is not complete and may be changed. We may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This preliminary prospectus is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any state where the offer or sale is not permitted.

Subject to completion

Dated August 10, 2026

Preliminary Prospectus

Up to 3,731,344 Shares of Common Stock

Up to 3,731,344 Pre-Funded Warrants to Purchase Up to 3,731,344 Shares of Common Stock

Up to 3,731,344 Common Warrants to Purchase up to 3,731,344 Shares of Common Stock

Up to 7,462,688 Shares of Common Stock underlying the Pre-Funded Warrants and Common Warrants

We are offering in a best-efforts offering up to 3,731,344 shares of common stock, par value $0.01 per share, (“Common Stock”) of Curis, Inc. (“Curis”, the “Company”, “our company”, “we” or “us”) together with up to 3,731,344 common warrants (“August 2026 Warrants”) to purchase up to 3,731,344 shares of Common Stock at an assumed combined public offering price of $4.02 per share of Common Stock and August 2026 Warrant, pursuant to this prospectus, which was the closing price of our Common Stock on the Nasdaq Capital Market (“Nasdaq”) on August 7, 2026. The Common Stock and August 2026 Warrants will be sold in a fixed combination, with each share of Common Stock accompanied by one August 2026 Warrant to purchase one share of Common Stock.

We are also offering to those purchasers, if any, whose purchase of our Common Stock in this offering would otherwise result in such purchaser, together with its affiliates and certain related parties, beneficially owning more than 9.99% of our outstanding common stock immediately following the consummation of this offering, the opportunity, in lieu of purchasing Common Stock, to purchase pre-funded warrants (“Pre-Funded Warrants”) to purchase Common Stock. Each Pre-Funded Warrant will be immediately exercisable for one share of Common Stock at any time at the option of the holder until such Pre-Funded Warrant is exercised in full, provided that the holder will be prohibited from exercising Pre-Funded Warrants for Common Stock if, as a result of such exercise, the holder, together with its affiliates and certain related parties, would own more than 9.99% of the total number of shares of common stock then issued and outstanding. The assumed combined purchase price of each Pre-Funded Warrant and August 2026 Warrant is $4.01 (assumed combined public offering price of $4.02 per share of Common Stock and August 2026 Warrant to be sold in this offering minus $0.01, the exercise price per share of common stock of each Pre-Funded Warrant). For each Pre-Funded Warrant we sell, the number of shares of Common Stock we are offering will be decreased on a one-for-one basis. The Pre-Funded Warrants will be sold together with August 2026 Warrants in a fixed combination, with each Pre-Funded Warrant accompanied by one August 2026 Warrant to purchase one share of Common Stock.

Each August 2026 Warrant will have an exercise price of $4.02 per share of Common Stock (which will be no less than 100% of the assumed public offering price per share of Common Stock to be sold in the offering), will be immediately exercisable upon issuance, and will expire on the five (5) year anniversary of the issuance date. Because we will issue an August 2026 Warrant for each share of Common Stock and for each Pre-Funded Warrant sold in this offering, the number of August 2026 Warrants sold in this offering will not change as a result of a change in the mix of Common Stock and Pre-Funded Warrants sold.

We are also registering the Common Stock issuable from time to time upon the exercise of the Pre-Funded Warrants and August 2026 Warrants offered hereby.

Our common stock is listed on The Nasdaq Capital Market under the symbol “CRIS”. On August 7, 2026, the last sale price of our common stock was $4.02 per share. There is no established public trading market for the Pre-Funded Warrants or August 2026 Warrants and we do not expect a market to develop. Without an active trading market, the liquidity of those warrants will be limited. In addition, we do not intend to list the Pre-Funded Warrants or August 2026 Warrants on Nasdaq, any other national securities exchange or any other trading system.

The assumed public offering price used throughout this prospectus has been included for illustration purposes only, and may not be indicative of the final public offering price. The actual public offering price will be negotiated between us and the purchasers, in consultation with the Placement Agents (as defined below), based, among other factors, on our recent operating results, the trading of our Common Stock prior to this offering and the general condition of the securities markets at the time of this offering, and will be determined at the time of pricing, and may be at a discount to the then current market price.

This offering will terminate on September 9, 2026, unless (i) the closing occurs prior thereto or (ii) we decide to terminate the offering (which we may do at any time in our discretion) prior to that date. The securities purchased in this offering are expected to be issued in a single closing. The public offering price per share of Common Stock (or Pre-Funded Warrant) will be fixed for the duration of this offering.

We expect to enter into a securities purchase agreement relating to the offering with those investors that choose to enter into such an agreement on the day that the registration statement of which this prospectus forms a part is declared effective and that the closing of the offering will end one trading day after we first enter into a securities purchase agreement relating to the offering. The offering will settle delivery versus payment (“DVP”)/receipt versus payment (“RVP”). That is, on the closing date, we will issue the shares of Common Stock directly to the account(s) at the Placement Agent identified by each purchaser; upon receipt of such shares, the Placement Agent shall promptly electronically deliver such shares to the applicable purchaser, and payment therefor shall be made by the Placement Agent (or their clearing firm) by wire transfer to us.

We have engaged A.G.P./Alliance Global Partners. (“A.G.P.”) and Laidlaw & Company (UK) Ltd. (“Laidlaw”) (the “Placement Agents”) to act as our exclusive placement agents in connection with this offering. The Placement Agents have agreed to use their reasonable best efforts to arrange for the sale of the securities offered by this prospectus. The Placement Agents are not purchasing or selling any of the securities we are offering and the Placement Agents are not required to arrange the purchase or sale of any specific number of securities or dollar amount. We have agreed to pay to the Placement Agents the placement agent fees set forth in the table below, which assumes that we sell all of the securities offered by this prospectus. There is no minimum offering requirement as a condition of closing of this offering. Because there is no minimum offering amount required as a condition to closing this offering, we may sell fewer than all of the securities offered hereby, which may significantly reduce the amount of proceeds received by us. We will bear all costs associated with the offering and investors in this offering will not receive a refund in the event that we do not sell an amount of securities sufficient to pursue our business goals described in this prospectus. There is no arrangement for funds to be received in escrow, trust or similar arrangement. Because there is no escrow account and no minimum offering amount, investors could be in a position where they have invested in our company, but we are unable to fulfill all of our contemplated objectives due to a lack of interest in this offering. Further, any proceeds from the sale of securities offered by us will be available for our immediate use, despite uncertainty about whether we would be able to use such funds to effectively implement our business plan. See “Plan of Distribution” for more information regarding these arrangements.

Investing in our securities involves a high degree of risk. You should review carefully the risks and uncertainties described in the section titled “Risk Factors” beginning on page 8 of this prospectus, and under similar headings in any amendments or supplements to this prospectus.

Neither the Securities and Exchange Commission (the “SEC”) nor any state securities commission has approved or disapproved of the securities to be issued under this prospectus or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

We expect to deliver the securities to the purchasers in the offering on or about August __, 2026, subject to satisfaction of certain conditions.

Lead Placement Agent

A.G.P.

Co-Placement Agent

LAIDLAW & COMPANY (UK) LTD.

The date of this prospectus is , 2026

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