Agenus Announces Data from Phase II Study of BOT+BAL in Combination with agent-797 in PD-1 Refractory Gastroesophageal Cancer to be Presented at AACR 2026

• Study highlights novel multi-mechanistic immunotherapy combination in checkpoint-refractory disease
• Data expected to inform immune modulation, treatment sequencing, and durability of response across hard-to-treat tumors

LEXINGTON, Mass.--(BUSINESS WIRE)--Agenus Inc. (Nasdaq: AGEN), a leader in immuno-oncology innovation, today announced that data from an investigator-initiated Phase II trial conducted at Memorial Sloan Kettering Cancer Center will be presented at the American Association for Cancer Research (AACR) Annual Meeting, taking place April 17–22, 2026, in San Diego, CA.

The study evaluates botensilimab (BOT) and balstilimab (BAL) in combination with agenT-797, an allogeneic iNKT cell therapy developed by MiNK Therapeutics, in patients with PD-1 refractory gastroesophageal cancer (GEC)—an area of significant unmet need where resistance to checkpoint inhibition remains a major clinical challenge.

Presentation Details:

Abstract Title: A phase II study of agenT-797, botensilimab (BOT) and balstilimab (BAL) in PD-1 refractory gastroesophageal cancer (GEC)

Presenter: Samuel L. Cytyrn, MD; Gastrointestinal Medical Oncologist, Memorial Sloan Kettering Cancer Center

Session Name: Phase II and Phase III Clinical Trials

Date/Time: April 20, 2026 | 2:00–5:00 PM PT; 5:00-8:00 PM EDT

Poster Section: 52

Abstract No.: CT166

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. 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.

About Botensilimab (BOT)

Botensilimab (BOT) is a human Fc enhanced multifunctional anti-CTLA-4 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 1,200 patients have been treated with botensilimab and/or balstilimab 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 more than 900 patients to date and has demonstrated clinical activity and a favorable tolerability profile in several tumor types.

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 2025, 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.