Filed Pursuant to Rule 424(b)(3)
Registration No. 333-290108
PROSPECTUS SUPPLEMENT
(To Prospectus dated September 15, 2025)
ImageneBio, Inc.
2,508,337 Shares of Common Stock
This prospectus supplement supplements the prospectus dated September 15, 2025 (the “Prospectus”), which forms a part of our registration statement on Form S-1 (No. 333-290108). This prospectus supplement is being filed to update and supplement the information in the Prospectus with certain information contained in our Current Report on Form 8-K, filed with the Securities and Exchange Commission on December 18, 2025 (the “Current Report”). Accordingly, we have attached the Current Report in relevant part to this prospectus supplement.
The Prospectus and this prospectus supplement relate to the proposed offer and resale or other disposition from time to time by the selling stockholders 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 December 17, 2025, the last reported sales price of our 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 be delivered with this prospectus supplement. This prospectus supplement is qualified by reference to the Prospectus, including any amendments or supplements thereto, except to the extent that the information provided by this prospectus supplement supersedes information contained in the Prospectus.
This prospectus supplement is not complete without, and may not be delivered or used except in conjunction with, the Prospectus, including any amendments or supplements to it.
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 6 of the Prospectus, and under similar headings in any amendments or supplements to the Prospectus.
Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities, or passed upon the accuracy or adequacy of this prospectus supplement. Any representation to the contrary is a criminal offense.
The date of this prospectus supplement is December 18, 2025
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM 8-K
CURRENT REPORT
Pursuant to Section 13 OR 15(d)
of The Securities Exchange Act of 1934
Date of Report (Date of earliest event reported): December 12, 2025
IMAGENEBIO, INC.
(Exact name of registrant as specified in its charter)
| Delaware | 001-40287 | 81-1697316 | ||
| (State or other jurisdiction of incorporation) |
(Commission File Number) |
(I.R.S. Employer Identification No.) |
| 12526 High Bluff Drive, Suite 345 | ||
| San Diego, California | 92130 | |
| (Address of principal executive offices) | (Zip Code) |
Registrant’s telephone number, including area code: (858) 345-6265
Not Applicable
(Former Name or Former Address, if Changed Since Last Report)
Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:
| ☐ | Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) |
| ☐ | Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) |
| ☐ | Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) |
| ☐ | Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) |
Securities registered pursuant to Section 12(b) of the Act:
| Title of each class |
Trading |
Name of each exchange on which registered | ||
| Common Stock, $0.001 par value | IMA | The Nasdaq Capital Market |
Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).
Emerging growth company ☒
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 13(a) of the Exchange Act. ☐
| Item 5.02 | Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers. |
On December 12, 2025, Yufang Lu, M.D., Ph.D., our Chief Medical Officer, provided notice of her resignation, effective December 31, 2025. Dr. Lu’s resignation was not due to any disagreement on any matter relating to our operations, policies or practices. We are conducting a search for Dr. Lu’s replacement. Dr. Lu is expected to provide transition advisory services following her resignation date.
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 the undersigned hereunto duly authorized.
| IMAGENEBIO, INC. | ||||||
| Date: December 18, 2025 | By: | /s/ Kristin Yarema | ||||
| Kristin Yarema, Ph.D. | ||||||
| Chief Executive Officer | ||||||