Contingencies	9 Months Ended
Sep. 30, 2025
Commitments and Contingencies Disclosure [Abstract]
Contingencies	Note S – Contingencies In September 2024, a putative securities class action lawsuit captioned In re Agenus Inc. Securities Litigation, No. 1:24-cv-12299, was filed in the U.S. District Court for the District of Massachusetts (the “Court”) against the Company and certain of its executives and directors. The Court appointed a lead plaintiff pursuant to the Private Securities Litigation Reform Act, and the lead plaintiff filed an amended complaint on February 7, 2025. The amended complaint alleges that Agenus, three of its current officers, and one member of its advisory board violated Sections 10(b) and 20(a) of the Securities Exchange Act of 1934, as amended, and Rule 10b-5 thereunder, by making false and misleading statements and omissions of material fact related to the efficacy and commercial prospects of botensilimab and balstilimab. The lead plaintiff seeks to represent all persons who purchased or otherwise acquired Agenus securities between January 23, 2023, and July 17, 2024, and seeks damages and interest, and an award of costs, including attorneys’ fees. On April 8, 2025, the Company moved to dismiss the securities class action. On June 6, 2025 plaintiff filed an opposition to the motion to dismiss, and on July 7, 2025, the Company filed its reply brief. As of the date of this filing, the Company’s motion to dismiss is pending before the court. We are unable to estimate a range of loss, if any, that could result were there to be an adverse decision in this action. The Company has been served with four derivative actions filed in the Court between November 2024 and January 2025 by purported stockholders. The actions name certain of the Company’s executives and directors and allege that the defendants made false or misleading statements and omissions of material fact related to the efficacy and commercial prospects of botensilimab and balstilimab. On May 2, 2025, the Court consolidated the four actions in Case No. 1:24-cv-12823 and stayed all deadlines pending future developments in the securities class action. We are unable to estimate a range of loss, if any, that could result were there to be an adverse decision in this action. In September 2024, we received a subpoena from the Boston Regional Office of the U.S. Securities and Exchange Commission seeking records relating to certain of our product candidates, correspondence with the FDA, public disclosure, and other matters. We have produced records pursuant to the subpoena. We are unable to estimate a range of loss, if any, that could result were there to be an adverse decision in this action.

Contingencies

9 Months Ended

Sep. 30, 2025

Commitments and Contingencies Disclosure [Abstract]

Note S – Contingencies

In September 2024, a putative securities class action lawsuit captioned In re Agenus Inc. Securities Litigation, No. 1:24-cv-12299, was filed in the U.S. District Court for the District of Massachusetts (the “Court”) against the Company and certain of its executives and directors. The Court appointed a lead plaintiff pursuant to the Private Securities Litigation Reform Act, and the lead plaintiff filed an amended complaint on February 7, 2025. The amended complaint alleges that Agenus, three of its current officers, and one member of its advisory board violated Sections 10(b) and 20(a) of the Securities Exchange Act of 1934, as amended, and Rule 10b-5 thereunder, by making false and misleading statements and omissions of material fact related to the efficacy and commercial prospects of botensilimab and balstilimab. The lead plaintiff seeks to represent all persons who purchased or otherwise acquired Agenus securities between January 23, 2023, and July 17, 2024, and seeks damages and interest, and an award of costs, including attorneys’ fees. On April 8, 2025, the Company moved to dismiss the securities class action. On June 6, 2025 plaintiff filed an opposition to the motion to dismiss, and on July 7, 2025, the Company filed its reply brief. As of the date of this filing, the Company’s motion to dismiss is pending before the court. We are unable to estimate a range of loss, if any, that could result were there to be an adverse decision in this action.

The Company has been served with four derivative actions filed in the Court between November 2024 and January 2025 by purported stockholders. The actions name certain of the Company’s executives and directors and allege that the defendants made false or misleading statements and omissions of material fact related to the efficacy and commercial prospects of botensilimab and balstilimab. On May 2, 2025, the Court consolidated the four actions in Case No. 1:24-cv-12823 and stayed all deadlines pending future developments in the securities class action. We are unable to estimate a range of loss, if any, that could result were there to be an adverse decision in this action.

In September 2024, we received a subpoena from the Boston Regional Office of the U.S. Securities and Exchange Commission seeking records relating to certain of our product candidates, correspondence with the FDA, public disclosure, and other matters. We have produced records pursuant to the subpoena. We are unable to estimate a range of loss, if any, that could result were there to be an adverse decision in this action.