Botensilimab/Balstilimab Breakthrough Data Presented at ASCO-GI Shows Unprecedented Tumor Shrinkage and Robust Biomarker Response in Prevalent Colorectal Cancer Population

Core Insights - Agenus Inc. announced results from the NEST-1 study, evaluating the combination of botensilimab and balstilimab for colorectal cancer treatment, presented by Dr. Pashtoon Kasi at the ASCO-GI conference [1][2] Study Highlights - Treatment involved a single dose of botensilimab (BOT) and two doses of balstilimab (BAL) administered between diagnosis and surgery, approximately over four weeks [3] - In the Microsatellite Stable (MSS) CRC cohort, 67.5% of patients experienced tumor shrinkage of ≥50%, while 100% of patients in the Microsatellite Instability-High (MSI-H) CRC cohort showed similar results [3] - The treatment did not delay surgical procedures, with only two instances of Grade 3 Treatment-Related Adverse Events (TRAEs) reported [3] - The study demonstrated that BOT/BAL eliminated circulating tumor DNA (ctDNA) in 100% of tested patients, which is associated with long-term Disease-Free Survival (DFS) [3] - An independent observational study indicated that patients who remained ctDNA negative post-treatment had better 2-year DFS rates compared to ctDNA-positive patients [3] Expert Commentary - Dr. Steven O'Day, Chief Medical Officer of Agenus, highlighted the remarkable results of the NEST-1 trial, noting significant tumor regression and immune cell infiltration in a short time frame, particularly in the MSS CRC cohort, which constitutes 90% of all CRC cases [4] About Botensilimab - Botensilimab is an investigational multifunctional anti-CTLA-4 immune activator designed to enhance both innate and adaptive anti-tumor immune responses, particularly in "cold" tumors that typically respond poorly to standard therapies [5] Clinical Development - Approximately 750 patients have been treated with botensilimab in phase 1 and phase 2 clinical trials, showing clinical responses across nine metastatic, late-line cancers [6] Company Overview - Agenus is a leading immuno-oncology company focused on cancer and infectious diseases, with a comprehensive pipeline of immunological agents aimed at expanding patient populations benefiting from cancer immunotherapy [7]