LEXINGTON, Mass., April 3, 2026
Agenus Inc. has announced that new data from its Phase II clinical study evaluating botensilimab (BOT) and balstilimab (BAL) in combination with agenT-797 will be presented at the American Association for Cancer Research (AACR) Annual Meeting 2026, highlighting a novel multi-mechanistic immunotherapy approach for patients with PD-1 refractory gastroesophageal cancer (GEC). This development represents a significant step forward in addressing checkpoint inhibitor resistance, a major clinical challenge in oncology, and underscores the potential of combination immunotherapy strategies to improve outcomes in hard-to-treat cancers.
Phase II Study Targets Checkpoint-Resistant Cancer
The investigator-initiated Phase II study, conducted at Memorial Sloan Kettering Cancer Center, evaluates a triple-combination immunotherapy regimen consisting of botensilimab (a next-generation anti-CTLA-4 antibody), balstilimab (an anti-PD-1 antibody), and agenT-797 (an allogeneic invariant natural killer T-cell therapy). The study specifically targets patients with PD-1 refractory gastroesophageal cancer, a population with limited treatment options and poor prognosis.
The clinical data to be presented at AACR 2026 is expected to provide insights into immune modulation, treatment sequencing, and durability of response, key factors that determine long-term success in immuno-oncology. This approach reflects a growing trend in oncology toward combination therapies designed to overcome resistance mechanisms and enhance anti-tumor immune responses.
Multi-Mechanistic Immunotherapy Enhances Anti-Tumor Response
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The therapeutic strategy combines complementary mechanisms of action to maximize clinical benefit. Botensilimab is engineered as a multifunctional Fc-enhanced anti-CTLA-4 antibody, designed to activate both innate and adaptive immune responses, while reducing regulatory T-cell activity within tumors. Balstilimab, a fully human anti-PD-1 monoclonal antibody, blocks immune checkpoint pathways that suppress T-cell activation, thereby restoring immune system recognition of cancer cells.
The addition of agenT-797, an allogeneic iNKT cell therapy, introduces a cell-based immunotherapy component that enhances immune activation and may improve tumor infiltration and response durability. This multi-layered immunotherapy approach aims to convert “cold” tumors into responsive ones, addressing a major limitation of existing therapies in checkpoint-resistant cancers.
Addressing High Unmet Need in Gastroesophageal Cancer
Gastroesophageal cancer (GEC) remains a highly aggressive malignancy, with many patients developing resistance to PD-1 inhibitors, limiting treatment effectiveness in later lines of therapy. The development of innovative combination immunotherapies is critical to improving outcomes in this patient population. Agenus’ pipeline, which includes antibody therapeutics, adoptive cell therapies, and immune-modulating agents, reflects a comprehensive strategy to expand the reach of cancer immunotherapy across multiple tumor types. To date, over 1,200 patients have been treated with botensilimab and/or balstilimab in clinical trials, demonstrating clinical activity across several metastatic cancers. The upcoming data presentation at AACR is expected to further validate the clinical potential of this combination strategy, potentially influencing future treatment paradigms and clinical development pathways in oncology.
With its innovative multi-mechanistic approach and strong clinical rationale, Agenus is advancing the frontier of immuno-oncology, leveraging next-generation antibody and cell therapy combinations to address some of the most challenging cancers, while contributing to the broader evolution of precision medicine and targeted cancer therapies.
Source: Agenus press release
