On April 17, 2026 Agenus Inc. (Nasdaq: AGEN), a leader in immuno-oncology innovation, reported data from an investigator-initiated Phase II trial at Memorial Sloan Kettering Cancer Center, investigating botensilimab (BOT) and balstilimab (BAL) in combination with agenT-797, MiNK’s allo-iNKT cell therapy, ramucirumab and paclitaxel in patients with advanced PD-1 refractory gastroesophageal adenocarcinoma. The data are being presented at the American Association for Cancer Research (AACR) (Free AACR Whitepaper) Annual Meeting, taking place April 17-22, 2026, in San Diego, CA.

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This Phase II trial, which is the first to combine BOT and BAL with agenT-797 in patients with gastroesophageal cancer who progressed after frontline therapy, was designed to explore the role of immune priming and treatment sequencing. Patients received induction with agenT-797 (alone or plus BOT/BAL) followed by the full combination regimen, or initiated the combination without induction, with longitudinal biomarker sampling throughout. In this study (n=17), the regimen delivered a 77% DCR with long-term survival beyond 20 months in a subset, and the induction arm showed meaningful gains in PFS (6.9 vs. 3.5 months; HR 0.19; p=0.015) and OS (9.5 vs. 5.2 months), with 43% of induction-treated patients alive at both 12 and 18 months—underscoring that durability and survival may be the most clinically relevant endpoints in this PD-1 refractory population.

"These findings illustrate the mechanistic synergy of agenT-797 with botensilimab and balstilimab in this PD-1 refractory setting," said Dhan Chand, Ph.D., Vice President of Research at Agenus. "The induction approach promoted significant intratumoral infiltration of T cells and dendritic cells, the formation of organized tertiary lymphoid structures in on-treatment biopsy tissue from a patient with durable benefit, and activation of peripheral CD4 and CD8 T-cell populations. These changes are consistent with immune priming and tumor immune reprogramming, providing a biological rationale for the improved progression-free survival observed with the induction strategy."

Efficacy findings from the Phase II (n=17) study included:

DCR was observed in 77% of all treated patients, and long-term survival beyond 20 months was seen in a subset
Patients who received induction cycle had longer progression-free survival (PFS) than those treated without induction, with median PFS of 6.9 months versus 3.5 months (HR 0.19; p=0.015), supporting the potential importance of immune priming and treatment sequencing.
Median overall survival (OS) was 9.5 months in the induction cohort versus 5.2 months without induction, with 43% of induction-treated patients alive at both 12 and 18 months, compared with 20% and 0%, respectively, in the non-induction cohort.
The study did not meet its primary endpoint of ORR; however, disease control and longer-term survival observed in a subset of patients support further study of this approach.
Correlative analyses showed that treatment with BOT, BAL, and agenT-797 was associated with significant intratumoral T cell and dendritic cell infiltration, the formation of organized tertiary lymphoid structures in on-treatment biopsies from a patient with prolonged benefit, and activation of peripheral CD4 and CD8 T cells.

The safety profile was consistent with the component agents. The most common treatment-emergent adverse events among all patients included fatigue, fever, diarrhea, anorexia, nausea and mucositis. Immune-related adverse events included dermatitis, colitis, gastritis, enteritis, hepatitis and hypothyroidism.

Additional analysis of the full biospecimen dataset is ongoing and is expected to provide further insight into immune mechanisms, optimal sequencing, and potential biomarkers that could help identify patients most likely to benefit.

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. Cytryn M.D.; 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

(Press release, Agenus, APR 17, 2026, View Source [SID1234664492])