Agenus to Present First Phase 2 Botensilimab Data in Advanced Cutaneous Melanoma at ASCO 2026

LEXINGTON, Mass.--(BUSINESS WIRE)--AgenusInc. (Nasdaq: AGEN), a leader in immuno-oncology innovation, today announced that four abstracts highlighting botensilimab (BOT), alone or in combination with balstilimab (BAL), have been accepted for presentation at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting, taking place May 29–June 2, 2026, in Chicago, Illinois.

The accepted abstracts reflect continued progress of Agenus’ botensilimab and balstilimab immunotherapy program across colorectal cancer, melanoma, and translational research. They include the first presentation of Phase 2 clinical data for BOT with or without BAL in advanced cutaneous melanoma refractory or resistant to anti–PD-(L)1 therapy, with or without prior CTLA-4 inhibition, as well as a translational biomarker abstract evaluating an artificial intelligence foundation model in solid tumors and two trials-in-progress posters in colorectal cancer.

“Our presence at ASCO reflects strong momentum across the botensilimab and balstilimab program. From the first Phase 2 melanoma presentation to important colorectal cancer trial updates and innovative translational biomarker research, these presentations underscore our focus on delivering new immunotherapy options to patients who need them most,” said Garo H. Armen, PhD, Chairman and CEO of Agenus.

• Abstract Title:Botensilimab (BOT) ± balstilimab (BAL) in patients (pts) with advanced cutaneous melanoma (cMEL) refractory/resistant (R/R) to anti–PD-(L)1 ± CTLA-4: A phase 2 trialAbstract No.:9543Presenter:Michael Atkins MD; Georgetown Lombardi Comprehensive Cancer Center, Georgetown University Medical CenterSession Title:Poster Session – Melanoma/Skin CancersLocation:Hall A – Posters and ExhibitsPoster Board:259Date/Time:May 31, 2026, 9:00 AM–12:00 PM CDT

• Abstract Title:Artificial intelligence (AI) foundation model as a predictor of efficacy of next-generation checkpoint inhibition with botensilimab (BOT) + balstilimab (BAL) in solid tumors using pretreatment H&E imagesAbstract No.:2535Presenter:Ryan Dalton, NoetikSession Title:Poster Session – Developmental Therapeutics—ImmunotherapyLocation:Hall A – Posters and ExhibitsPoster Board:325Date/Time:May 30, 2026, 1:30 PM–4:30 PM CDT

• Abstract Title:The CO.33/BATTMAN trial: A phase 3 randomized study of botensilimab + balstilimab versus best supportive care in chemo refractory unresectable colorectal adenocarcinoma that is not dMMR/MSI-HAbstract No.:TPS3676Presenter:Jonathan Loree MD; BC Cancer; Canadian Cancer Trials Group, Queen’s UniversitySession Title:Poster Session – Gastrointestinal Cancer—Colorectal and AnalLocation:Hall A – Posters and ExhibitsPoster Board:441aDate/Time:May 30, 2026, 9:00 AM–12:00 PM CDT

• Abstract Title:Phase 2 study of adjuvant botensilimab in combination with balstilimab in patients with microsatellite-stable colorectal cancer and persistent circulating tumor DNA following surgery and chemotherapyAbstract No.:TPS3689Presenter:Neil Segal, MD; Memorial Sloan Kettering Cancer CenterSession Title:Poster Session – Gastrointestinal Cancer—Colorectal and AnalLocation:Hall A – Posters and ExhibitsPoster Board:447bDate/Time:May 30, 2026, 9:00 AM–12:00 PM CDT

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, visitwww.agenusbio.comor @agenus_bio. Information that may be important to investors will be routinely posted on our website and social media channels.

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, visitwww.clinicaltrials.gov.

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.

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.