Agenus Announces New Data from Expanded MSS Metastatic Colorectal Cancer Cohort to be Presented at ESMO GI 2025

• Presenting new data in the most mature readout to date, with 60% more patients and reported median and 2-year overall survival.

Agenus Inc. (“Agenus” or the Company”) (NASDAQ: AGEN), a leader in immuno-oncology, today announced new data from its ongoing Phase 1 trial evaluating botensilimab and balstilimab (BOT/BAL) in patients with microsatellite stable (MSS) metastatic colorectal cancer (mCRC) at the 2025 European Society for Medical Oncology (ESMO) Gastrointestinal Cancers Congress in Barcelona, Spain. A poster presentation will feature updated findings from an expanded cohort of 123 patients, incorporating additional participants and extended follow-up to further assess clinical activity of the combination, including durability of response and overall survival (NCT03860272).

Presentation Details:

Presentation: Botensilimab plus balstilimab in an expanded cohort of 123 patients with metastatic microsatellite stable colorectal cancer and no active liver metastases

Presenting Author: Dr. Benjamin Schlechter, Dana Farber Cancer Institute

Poster Number: 8P

Session Date and Time: 7/4/2025, 3:30 PM – 4:30 PM CEST (9:30 AM – 10:30 AM EDT)

About Botensilimab (BOT)

Botensilimab is a human Fc enhanced CTLA-4 blocking antibody designed to boost both innate and adaptive anti-tumor immune responses. Its novel design leverages mechanisms of action to extend immunotherapy benefits to “cold” tumors which generally respond poorly to standard of care or are refractory to conventional PD-1/CTLA-4 therapies and investigational therapies. Botensilimab augments immune responses across a wide range of tumor types by priming and activating T cells, downregulating intratumoral regulatory T cells, activating myeloid cells and inducing long-term memory responses.

Approximately 1,100 patients have been treated with botensilimab in phase 1 and phase 2 clinical trials. Botensilimab alone, or in combination with Agenus’ investigational PD-1 antibody, balstilimab, has shown clinical responses across nine metastatic, late-line cancers. For more information about botensilimab trials, visit www.clinicaltrials.gov.

About Balstilimab (BAL)

Balstilimab is a novel, fully human monoclonal immunoglobulin G4 (IgG4) designed to block PD-1 (programmed cell death protein 1) from interacting with its ligands PD-L1 and PD-L2. It has been evaluated in >900 patients to date and has demonstrated clinical activity and a favorable tolerability profile in several tumor types.

About Agenus

Agenus is a leading immuno-oncology company targeting cancer with a comprehensive pipeline of immunological agents. The company was founded in 1994 with a mission to expand patient populations benefiting from cancer immunotherapy through combination approaches, using a broad repertoire of antibody therapeutics, adoptive cell therapies (through MiNK Therapeutics) and adjuvants (through SaponiQx). Agenus has robust end-to-end development capabilities, across commercial and clinical cGMP manufacturing facilities, research and discovery, and a global clinical operations footprint. Agenus is headquartered in Lexington, MA. For more information, visit www.agenusbio.com or @agenus_bio. Information that may be important to investors will be routinely posted on our website and social media channels.

Forward-Looking Statements

This press release contains forward-looking statements that are made pursuant to the safe harbor provisions of the federal securities laws, including statements regarding its botensilimab and balstilimab programs, expected regulatory timelines and filings, and any other statements containing the words "may," "believes," "expects," "anticipates," "hopes," "intends," "plans," "forecasts," "estimates," "will," “establish,” “potential,” “superiority,” “best in class,” and similar expressions are intended to identify forward-looking statements. These forward-looking statements are subject to risks and uncertainties that could cause actual results to differ materially. These risks and uncertainties include, among others, the factors described under the Risk Factors section of our most recent Annual Report on Form 10-K for 2024, and subsequent Quarterly Reports on Form 10-Q filed with the Securities and Exchange Commission. Agenus cautions investors not to place considerable reliance on the forward-looking statements contained in this release. These statements speak only as of the date of this press release, and Agenus undertakes no obligation to update or revise the statements, other than to the extent required by law. All forward-looking statements are expressly qualified in their entirety by this cautionary statement.

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