ImageneBio Inc美股招股说明书(2025-12-18版)

ImageneBio, Inc. 2,508,337 Shares of Common Stock This prospectus supplement supplements the prospectus dated September15, 2025 (the “Prospectus”), which forms a part of our registrationstatement on Form S-1 (No. 333-290108). This prospectus supplement is being filed to update and supplement the information in the Prospectus withcertain information contained in our Current Report on Form 8-K, filed with the Securities and Exchange Commission on December18, 2025 (the The Prospectus and this prospectus supplement relate to the proposed offer and resale or other disposition from time to time by the sellingstockholders identified in this prospectus of 2,508,337 shares of common stock, par value $0.001 per share (the “Common Stock”), of ImageneBio, Inc. Our Common Stock is listed on the Nasdaq Capital Market under the ticker symbol “IMA.” On December17, 2025, the last reported sales price ofour Common Stock on the Nasdaq Capital Market was $6.24 per share. This prospectus supplement should be read in conjunction with the Prospectus, including any amendments or supplements to it, which is to bedelivered with this prospectus supplement. This prospectus supplement is qualified by reference to the Prospectus, including any amendments or This prospectus supplement is not complete without, and may not be delivered or used except in conjunction with, the Prospectus, including any Investing in our securities involves a high degree of risk. You should review carefully the risks and uncertaintiesdescribed in the section titled “Risk Factors” beginning on page 6 of the Prospectus, and under similar headings in anyamendments or supplements to the Prospectus. Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities, orpassed upon the accuracy or adequacy of this prospectus supplement. Any representation to the contrary is a criminal offense. If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with anynew or revised financial accounting standards provided pursuant to Section13(a) of the Exchange Act.☐ Item 5.02Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; CompensatoryArrangements of Certain Officers.On December12, 2025, Yufang Lu, M.D., Ph.D., our Chief Medical Officer, provided notice of her resignation, effective December31, 2025. Dr.Lu’s SIGNATURE Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by theundersigned hereunto duly authorized. IMAGENEBIO, INC. By:/s/ Kristin YaremaKristin Yarema, Ph.D. Date: December18, 2025