8-K

UNITED STATESSECURITIES AND EXCHANGE COMMISSIONWASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

AGENUS INC.

(Exact name of Registrant as Specified in Its Charter)

(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:

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 1.01 Entry into a Material Definitive Agreement.

On January 3, 2026, Agenus Inc. (the “Company”), Agenus Royalty Fund, LLC and Agenus Holdings 2024, LLC entered into an amendment and release agreement (the “Amendment Agreement”) with Ligand Pharmaceuticals Incorporated (“Ligand”) related to a Purchase and Sale Agreement and related Warrant each previously disclosed in the Company’s Current Report on Form 8-K filed with the SEC on May 7, 2024. The Amendment Agreement provides for a release by Ligand of liens it has on certain of the Company’s assets in exchange for a modification of the exercise price under the warrant from $17.30 per share to $7.50 per share.

The foregoing descriptions of the Amendment Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the Amendment Agreement, a copy of which will be filed, with confidential terms redacted, as an exhibit to the Company’s next period report, which will be its Annual Report on Form 10-K.

Item 3.03 Material Modification to Rights of Security Holders.

The information contained in Item 1.01 of this Current Report on Form 8-K is incorporated by reference into this Item 3.03.

SIGNATURES

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.