Immuneering Corp-A美股招股说明书(2025-09-24版)

Shares of ClassA Common Stock Pre-Funded Warrants to Purchase We are offeringshares of our ClassA common stock, at a price of $per share, or, in lieu of shares of ClassAcommon stock, pre-funded warrants to purchaseshares of our ClassA common stock, at a price of $perunderlying share (which is equal to the price per share of ClassA common stock being sold in this offering, minus $0.001, which isthe exercise price per share of the pre-funded warrant). Each pre-funded warrant will be immediately exercisable for shares of ClassA common stock, subject to the beneficialownership and other limitations described in the section “Description of Securities We Are Offering.” We refer to the ClassAcommon stock underlying the pre-funded warrants as the warrant shares; and we refer to the shares and pre-funded warrants, togetherwith the warrant shares, collectively, as the securities. This prospectus supplement also relates to the offering of the warrant shares.See “Description of Securities We Are Offering.” Our ClassA common stock is listed on The Nasdaq Global Market under the symbol “IMRX.” On September23, 2025, the lastreported sale price for our ClassA common stock on The Nasdaq Global Market was $8.59 per share. There is no established publictrading market for the pre-funded warrants and we do not expect a market to develop. We do not intend to list the pre-fundedwarrants on the Nasdaq Global Market, any other national securities exchange or any other recognized trading system. On September24, 2025, we entered into a securities purchase agreement with Aventis Inc. (referred to herein as the Investor), awholly owned subsidiary of Sanofi, a French société anonyme, pursuant to which the Investor agreed to purchase, subject to certainconditions, up to $25.0million of our ClassA common stock, or in certain situations in lieu of shares of ClassA common stock,shares of our non-voting ClassB common stock, in a private placement. Under the terms of the securities purchase agreement, theprivate placement is subject to and contingent upon the closing of a firm commitment underwritten public offering by us of ourClassA common stock that results in gross proceeds to us of at least $75.0million and the pricing of which is publicly announced ina press release issued by us on or before September26, 2025 (referred to herein as a qualified public offering), and is expected toclose concurrent with the completion of the qualified public offering. The purchase price per share of ClassA common stock (or pershare of ClassB common stock in lieu of ClassA common stock) shall be the public offering price per share at which our ClassAcommon stock is sold to the public in the qualified public offering. We intend that this offering shall constitute the qualified publicoffering. The sale of the shares in the concurrent private placement will not be registered under the Securities Act of 1933, asamended, or the Act. The closing of this offering is not conditioned upon the closing of the concurrent private placement. Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of thesesecurities or passed upon the accuracy or adequacy of this prospectus supplement or the accompanying prospectus. Any representation tothe contrary is a criminal offense. Investing in our securities involves risks. See “Risk Factors” beginning on pageS-9of this prospectus supplement and in thedocuments incorporated by reference in this prospectus supplement concerning factors you should consider before investing in oursecurities. Per SharePerPre-FundedWarrantTotalPublic offering price$$$Underwriting discounts and commissions$$$Proceeds to us, before expenses$$$(1) (1)We have agreed to pay the underwriters a commission equal to 6.0% of the aggregate gross proceeds from the sale of thesecurities in this offering. We have also agreed to reimburse the underwriters for certain of their expenses. See “Underwriting”beginning on pageS-26of this prospectus supplement for more information about these arrangements. We have granted the underwriters the option to purchase up toadditional shares of our ClassA common stock from usat the public offering price, less underwriting discounts and commissions. The underwriters may exercise this right at any time, inwhole or in part, within 30days following the date of this prospectus supplement. The underwriters expect to deliver the shares of ClassA common stock (or pre-funded warrants in lieu thereof) to investors onor about, 2025. The shares of ClassA common stock will be delivered in book-entry form through the facilities of TheDepository Trust Company on or about, 2025. The pre-funded warrants will be delivered to purchasers in certificatedform.The information in this preliminary prospectus supplement and the accompanying prospectus, relating to an effective registration statement under the Securities Act of 1933, as amended, is notcomplete and may be changed. A registratio