Agenus to Showcase Initial Phase 2 Botensilimab Results in Advanced Cutaneous Melanoma at ASCO 2026
Agenus Inc. (Nasdaq: AGEN), a clinical-stage immuno-oncology company focused on developing next-generation cancer immunotherapies, announced today that four scientific abstracts featuring its lead checkpoint inhibitor combination—botensilimab (BOT) and balstilimab (BAL)—have been accepted for presentation at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting. The conference will be held from May 29 to June 2, 2026, in Chicago, Illinois, and is widely regarded as one of the most influential global forums for oncology research and clinical innovation.
The accepted abstracts reflect continued advancement of Agenus’ dual immunotherapy program across multiple tumor types, including colorectal cancer, melanoma, and translational biomarker research. Collectively, they underscore the company’s ongoing efforts to expand the clinical utility of botensilimab and balstilimab, particularly in difficult-to-treat cancers that have shown resistance to existing immune checkpoint inhibitors.
A central highlight of the ASCO presentations is the first disclosure of Phase 2 clinical data evaluating botensilimab, both as a monotherapy and in combination with balstilimab, in patients with advanced cutaneous melanoma. These patients had disease that was refractory or resistant to prior anti–PD-(L)1 therapies, with or without previous exposure to CTLA-4 inhibition. Given the limited treatment options for this heavily pretreated population, the results are expected to provide important insights into the potential of next-generation immunotherapy combinations to overcome resistance mechanisms.
In addition to melanoma data, Agenus will present a translational research abstract exploring the role of artificial intelligence in predicting immunotherapy response. This study evaluates an AI foundation model that analyzes pre-treatment hematoxylin and eosin (H&E) stained tumor images to predict the efficacy of botensilimab plus balstilimab in solid tumors. The use of AI-driven pathology represents a growing area of interest in oncology, as researchers aim to better understand which patients are most likely to benefit from immune checkpoint blockade therapies. By integrating computational pathology with clinical outcomes, the study seeks to enhance patient selection and improve therapeutic precision.
The remaining two abstracts focus on colorectal cancer, a key therapeutic area for Agenus’ immunotherapy platform. One of these is a Phase 3 trial-in-progress titled CO.33/BATTMAN, which evaluates the combination of botensilimab and balstilimab versus best supportive care in patients with chemo-refractory, unresectable colorectal adenocarcinoma that is not characterized by deficient mismatch repair (dMMR) or microsatellite instability-high (MSI-H) status. This patient population typically has limited response to standard immunotherapy approaches, making it a significant unmet medical need.
The second colorectal cancer abstract describes a Phase 2 adjuvant study investigating botensilimab in combination with balstilimab in patients with microsatellite-stable colorectal cancer who continue to exhibit detectable circulating tumor DNA (ctDNA) after surgery and chemotherapy. The presence of ctDNA after standard treatment is associated with a higher risk of disease recurrence, and this study aims to determine whether early immunotherapy intervention can reduce relapse rates and improve long-term outcomes in this high-risk population.
Garo H. Armen, PhD, Chairman and Chief Executive Officer of Agenus, emphasized that the company’s ASCO 2026 presence reflects strong momentum across its immunotherapy pipeline. He noted that the breadth of presentations—from early translational research to late-stage clinical development programs—demonstrates the versatility and scientific depth of the botensilimab and balstilimab combination.
According to Dr. Armen, the inclusion of a first Phase 2 melanoma dataset marks an important milestone in the clinical development of the program. He also highlighted the significance of ongoing colorectal cancer studies, which continue to explore the potential of Agenus’ immunotherapy approach in tumor types that have historically been resistant to checkpoint inhibition. In addition, he pointed to the AI-driven biomarker research as an example of how the company is integrating advanced computational tools to refine treatment strategies and improve patient outcomes.
Botensilimab is designed as a next-generation CTLA-4 antibody engineered to enhance immune activation while potentially improving tolerability compared to earlier CTLA-4-targeting agents. Balstilimab, on the other hand, is an anti–PD-1 antibody that works by restoring T-cell activity against tumor cells. When used in combination, the two agents are intended to provide a synergistic immune response, potentially overcoming resistance seen with single-agent checkpoint inhibitors.
The clinical rationale for combining these agents lies in their complementary mechanisms of action. While PD-1 inhibition primarily reinvigorates exhausted T cells within the tumor microenvironment, CTLA-4 blockade enhances early T-cell activation and expands the pool of tumor-reactive immune cells. Together, these effects may result in a broader and more durable anti-tumor response, particularly in cancers that are traditionally considered immunologically “cold.”
All four abstracts accepted for ASCO 2026 will be presented in poster sessions at the conference, with detailed schedules spanning May 30 and May 31. The melanoma study will be presented by Dr. Michael Atkins of Georgetown Lombardi Comprehensive Cancer Center, while the AI biomarker research will be presented by Ryan Dalton of Noetik. The colorectal cancer studies will be presented by Dr. Jonathan Loree of BC Cancer and the Canadian Cancer Trials Group at Queen’s University, and Dr. Neil Segal of Memorial Sloan Kettering Cancer Center, respectively.
The melanoma poster session will take place on May 31, 2026, from 9:00 AM to 12:00 PM Central Daylight Time in Hall A of the exhibition area. The AI biomarker and colorectal cancer presentations are scheduled for May 30, 2026, across morning and afternoon sessions, also in Hall A’s poster and exhibit section.
Agenus’ participation at ASCO 2026 comes at a time when immuno-oncology continues to evolve rapidly, with increasing focus on overcoming resistance to existing checkpoint inhibitors and expanding treatment benefits to a broader range of tumor types. Despite significant advances in the field, many patients with solid tumors such as colorectal cancer and melanoma still fail to respond to currently available immunotherapies, underscoring the need for novel approaches like botensilimab and balstilimab.
By presenting new clinical data, ongoing trial updates, and translational research findings at ASCO, Agenus aims to further validate its immunotherapy platform and strengthen its position in the competitive oncology landscape. The company’s continued progress across multiple clinical programs reflects its broader strategy of developing differentiated immune-based therapies designed to improve outcomes in patients with limited or no effective treatment options.
As ASCO 2026 approaches, investor and scientific attention is expected to focus on the emerging efficacy and safety profile of botensilimab-based regimens, particularly in refractory melanoma and microsatellite-stable colorectal cancer—two areas where durable responses to immunotherapy have historically been difficult to achieve.
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