Agenus' Botensilimab Study Shows Unprecedented Tumor Shrinkage

(RTTNews) - Agenus Inc. (AGEN), Monday announced results from the NEST-1 study, an investigator-sponsored trial (IST) evaluating the combination of botensilimab and balstilimab (BOT/BAL) in the neoadjuvant setting for colorectal cancer (CRC), both those with Microsatellite Stable (MSS) CRC and Microsatellite Instability High (MSI-H) CRC.

Botensilimab is an investigational multifunctional anti-CTLA-4 immune activator (antibody) designed to boost both innate and adaptive anti-tumor immune responses. Its novel design leverages mechanisms of action to extend immunotherapy benefits to "cold" tumors which generally respond poorly to standard of care or are refractory to conventional PD-1/CTLA-4 therapies and investigational therapies.

"BOT/BAL's potential impact on colorectal cancer is groundbreaking. The study's findings, particularly the significant tumor regression after only a single dose of BOT and two doses of BAL, and the complete elimination of ctDNA in 100% of patients tested, offer a potentially transformative treatment approach for CRC patients diagnosed with early stage and locally advanced colon and rectal cancers. These results hold great promise for patients and providers as a framework for reduced reliance on chemotherapy and/or surgical resection," said Dr. Pashtoon Kasi, M.D., Director of Colon Cancer Research at Weill-Cornell Medicine and lead investigator of the NEST-1 study.

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 (90% of all CRC) are particularly compelling and may lead to an unprecedented shift away from invasive and morbid standard treatments in the future."