C4 Therapeutics Inc美股招股说明书(2025-12-10版)

$125,000,000 Common Stock We have previously entered into a sales agreement, or the Sales Agreement, with TD Securities (USA) LLC, which we refer to as TD Cowen or theSales Agent, relating to shares of our common stock, par value $0.0001 per share, offered by this prospectus supplement and the accompanyingprospectus. In accordance with the terms of the Sales Agreement, we may offer and sell shares of our common stock having an aggregate offering priceof up to $200,000,000 from time to time through the Sales Agent. This prospectus supplement relates to $125,000,000 of shares of our common stockthat we may sell pursuant to the Sales Agreement. Sales of the shares of common stock, if any, may be made on The Nasdaq Global Select Market atmarket prices and such other sales as agreed upon by us and the Sales Agent, as the case may be. We previously filed a prospectus supplement, datedNovember13, 2024, or the original prospectus supplement, relating to the sale of shares of our common stock from time to time pursuant to the SalesAgreement. Under the original prospectus supplement, we sold 3,769,483 shares of our common stock for gross proceeds of approximately $9.6millionof our common stock pursuant to the Sales Agreement. As disclosed in a Current Report on Form 8-K filed on October16, 2025, the original prospectussupplement was terminated, effective as of October16, 2025, and we have not issued any additional shares of our common stock pursuant to the SalesAgreement following the termination of the original prospectus supplement. Our common stock is listed on The Nasdaq Global Select Market under the symbol “CCCC”. On November20, 2025, the closing price of our commonstock, as reported on The Nasdaq Global Select Market, was $2.38 per share. Sales of our common stock, if any, under this prospectus supplement will be made in sales deemed to be an “at the market offering” as defined in Rule415(a)(4) promulgated under the Securities Act of 1933, as amended, or the Securities Act. The Sales Agent is not required to sell any specific numberor dollar amount of securities, but will use commercially reasonable efforts to sell on our behalf all of the shares of common stock requested to be soldby us, consistent with their normal trading and sales practices, on mutually agreed terms between the Sales Agent and us. There is no arrangement forfunds to be received in any escrow, trust or similar arrangement. The Sales Agent will be entitled to compensation at a commission rate of up to 3.0% of the gross sales price of common stock sold under the SalesAgreement. See “Plan of Distribution” beginning on page S-13 for additional information regarding the compensation to be paid to the Sales Agent. Inconnection with the sale of the common stock on our behalf, the Sales Agent will be deemed to be an “underwriter” within the meaning of the SecuritiesAct and the compensation of the Sales Agent will be deemed to be underwriting commissions or discounts. We have also agreed to provideindemnification and contribution to the Sales Agent with respect to certain liabilities, including liabilities under the Securities Act and the SecuritiesExchange Act of 1934, as amended, or the Exchange Act. Investing in our common stock involves a high degree of risk. You should review carefully the risks anduncertainties referenced under the heading “Risk Factors” on page S-5 of this prospectus supplement and in thedocuments that are incorporated by reference into this prospectus supplement. Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities ordetermined if this prospectus supplement is truthful or complete. Any representation to the contrary is a criminal offense. TD Cowen The date of this prospectus supplement is December10, 2025 Table of Contents TABLE OF CONTENTSProspectus Supplement ABOUT THIS PROSPECTUS SUPPLEMENTPROSPECTUS SUPPLEMENT SUMMARYTHE OFFERINGRISK FACTORSCAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTSUSE OF PROCEEDSDIVIDEND POLICYDILUTIONPLAN OF DISTRIBUTIONLEGAL MATTERSEXPERTSWHERE YOU CAN FIND MORE INFORMATIONINCORPORATION BY REFERENCE Prospectus About This ProspectusRisk FactorsCautionary Statement Regarding Forward-Looking StatementsThe CompanyUse of ProceedsSecurities We May OfferDescription of Capital StockDescription of Debt SecuritiesDescription of WarrantsDescription of UnitsPlan of DistributionLegal MattersExpertsWhere You Can Find More InformationIncorporation by Reference We are responsible for the information contained and incorporated by reference in this prospectus supplement and in any related free writing prospectussupplement we prepare or authorize. We have not authorized anyone to give you any other information, and we take no responsibility for any otherinformation that others may give you. If you are in a jurisdiction where offers to sell, or solicitations of offers to purchase, the securities offered by thisdocumenta