Fakih Discusses Phase 2 Trial of Balstilimab Plus Botensilimab in MSS mCRC

Marwan G. Fakih, MD, professor in the Department of Medical Oncology & Therapeutics Research, co-directs the Gastrointestinal Cancer Program at City of Hope Comprehensive Cancer Center, explains the implications of the findings from the phase 2 trial (NCT05608044) of balstilimab plus botensilimab for the treatment of patients with microsatellite stable (MSS) metastatic colorectal cancer (mCRC) without liver metastases.

Fakih presented on the trial at the 2025 Gastrointestinal Cancers Symposium.

Transcription:

0:10 | The primary end point is overall response rate, and I think we showed activity. Interestingly, this was in line with the data and results that were published in Nature Medicine in the large phase 1 trial with this combination, where the overall response rate was 23%, so I think it is confirmatory that the combination is effective.

0:33 | The other secondary end points were progression-free survival and overall survival. Those results are still being monitored and followed. They have not fully matured, but we did report that in our responders on this study, 70% continue to be without evidence of progression, and the median duration of response has not been met, indicating that the treatment is not only effective in shrinking the tumors and maintaining disease stability but that, in those patients who have a good response, it appears to be durable.

1:13 | Of note, the disease control rate on the combination arms was approximately 54% to 55% of patients, meaning more than half of the patients did benefit from the combination arm.

REFERENCE:

1. Fakih M, Segal NH, Schlechter BL, et al. Preliminary results from a randomized, open-label, phase 2 study of botensilimab (BOT) with or without balstilimab (BAL) in refractory microsatellite stable metastatic colorectal cancer with no liver metastases (MSS mCRC NLM). J Clin Oncol. 2025;43(suppl 4):23. doi:10.1200/JCO.2025.43.4_suppl.23