Material Agreement, Financial Obligation (Form 8-K)

Item 1.01 Entry into a Material Definitive Agreement.

Promissory Note Agreement

On October 8, 2025, Agenus Inc. ("Agenus") entered into a Promissory Note Agreement (the "Note") with Zydus Pharmaceuticals (USA) Inc. ("Zydus"), a wholly owned subsidiary of Zydus Lifesciences Limited, for up to $10,000,000 (the "Principal Amount"). The Note bears interest at 3.81% per annum and matures upon the closing of the Asset Purchase Agreement and Securities Purchase Agreement signed by Agenus and Zydus on June 3, 2025 (together, the "APA/SPA"), or, if such closings will not occur, within 10 days after notification that the APA/SPA closings will not be consummated. The Note contains terms and conditions, including representations and warranties, governing its issuance.

Use of Proceeds; Forgiveness Feature. Proceeds from the Note will (i) fund the operational expenses of the Emeryville and Berkeley facilities for the fourth quarter of 2025-which amount, pursuant to the Note, will be forgiven and not repaid if the APA/SPA close-and (ii) to make certain payments owed in respect of assets subject to the APA between the parties.

Collateral. As collateral for the Note, Agenus pledged 822,910 shares of common stock of MiNK Therapeutics, Inc. (NASDAQ: INKT) that are owned by Agenus. Agenus also executed a control agreement related to these shares, which control agreement provides certain rights to Zydus in the event that there is an event of default under the Note. Upon satisfaction of the obligations under the Note (including repayment or forgiveness in connection with an APA/SPA closing), the pledge is expected to be released in accordance with the Note and related agreements.

The foregoing summary of the Note, the related pledge agreement and the control agreement does not purport to be complete and is qualified in its entirety by reference to the full text of such agreements, copies of which will be filed, with confidential terms redacted as applicable, as exhibits to Agenus's Quarterly Report on Form 10 Q for the quarter ended September 30, 2025.

Item 2.03 Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant.

The disclosures set forth in Item 1.01 with respect to the Note and related pledge agreement and control agreement are hereby incorporated into this Item 2.03 by reference.