Agenus: Botensilimab/balstilimab data shows tumor shrinkage, biomarker response

Agenus announced results from the NEST-1 study, an investigator-sponsored trial evaluating the combination of botensilimab and balstilimab in the neoadjuvant setting for colorectal cancer, both those with Microsatellite Stable CRC and Microsatellite Instability High CRC. Dr. Pashtoon Kasi, M.D., Director of Colon Cancer Research at Weill-Cornell Medicine, presented these findings at the ASCO-GI conference. Study Highlights: Treatment Protocol: Patients received a single dose of BOT and two doses of BAL between diagnosis and surgery, which was approximately a four-week period. Impressive Pathologic Response: Tumor shrinkage of greater than or equal to50% was observed in 67.5% of patients in the Microsatellite Stable CRC cohort and 100% in the Microsatellite Instability-High CRC cohort. Surgery Without Delays: Treatment with BOT/BAL did not cause any postponements in surgical procedures, with only two instances of Grade 3 Treatment-Related Adverse Events observed. BOT/BAL Eliminates Circulating Tumor DNA: patients in the NEST-1 study were tested for ctDNA, a biomarker closely associated with long-term Disease-Free Survival. In a separate, independent observational study of 1,792 patients, also led by Dr. Kasi and presented at the ASCO-GI meeting on January 20th, showed a correlation between ctDNA clearance and improved disease-free survival rates. Patients who remained ctDNA negative post-treatment exhibited better 2-year DFS as compared to ctDNA-positive patients. Dr. Steven O’Day, Chief Medical Officer of Agenus, stated, “The NEST-1 trial results are remarkable. Neoadjuvant BOT/BAL in both MSS and MSI-H CRC resulted in marked tumor regression and robust immune cell infiltration in a very short interval. These results in MSS CRC are particularly compelling and may lead to an unprecedented shift away from invasive and morbid standard treatments in the future.”