Significant Tumor Reduction with Botensilimab/Balstilimab in Neoadjuvant MSS Colon Cancer Treatment at ESMO GI Conference

A clinical trial for colon cancer treatment with botensilimab and balstilimab revealed significant tumor reductions and rapid responses in patients with microsatellite stable (MSS) colon cancer. The combination therapy displayed exceptional activity in the neoadjuvant setting, with over 75% of patients achieving at least 50% tumor regression, and 56% achieving complete responses. No surgeries were delayed due to treatment effects, signaling potential curative potential.

In a recent clinical trial presented at the European Society for Medical Oncology (ESMO) Gastrointestinal Cancers Congress, promising results were reported for the combination therapy of botensilimab and balstilimab (BOT/BAL) in treating microsatellite stable (MSS) colon cancer in the neoadjuvant setting [1]. This innovative approach has shown potential for improving patient outcomes and offering new hope for those facing this challenging cancer subtype.

Dr. Pashtoon Kasi, the lead researcher of this study, reported that the rapid and complete resolution of aggressive MSS colorectal cancer tumors observed in the trial is unprecedented in the field. The exceptional activity of the BOT/BAL combination therapy in the neoadjuvant setting offers new hope for patients who previously had limited treatment options [1]. The promising findings indicate that the body's own immune system can be harnessed to fight cancer effectively.

The trial included 20 patients, with 17 having MSS and 3 having high microsatellite instability (MSI-H) colon cancer. Both cohorts received one dose of botensilimab and one dose of balstilimab. The NEST-1 cohort received an additional dose of balstilimab two weeks later, while the NEST-2 cohort received up to three additional doses of balstilimab.

In the NEST-2 cohort, an impressive 78% (7/9) of MSS patients achieved pathologic responses of at least 50% tumor regression, with 56% (5/9) reaching complete pathologic responses [1]. Notably, no surgeries were delayed due to adverse events, and no patients experienced unresolved immune-related adverse events. Side effects were manageable, and no new safety concerns emerged.

Comparing the findings across the two cohorts, 71% (12/17) of MSS patients in the overall study achieved pathologic responses of at least 50% tumor regression, while 35% (6/17) reached complete pathologic responses. In contrast, 100% (3/3) of MSI-H patients achieved complete pathologic responses [1]. These results further emphasize the potential benefits of the BOT/BAL combination therapy for MSS colon cancer patients.

The innovative approach of using botensilimab and balstilimab in the neoadjuvant setting for MSS colon cancer shows promising results, with the potential to improve patient outcomes and offer new hope for those facing this challenging cancer subtype. The findings of this study highlight the importance of continued research in the field of immunotherapy and the potential for personalized treatment approaches.

References:
[1] Agenus Inc. (2024, June 28). Significant Tumor Reductions in Neoadjuvant MSS Colon Cancer Patients Treated with Botensilimab/Balstilimab Presented at ESMO GI Conference. BusinessWire. Retrieved from https://www.businesswire.com/news/home/20240628005162/en/