Phase III KEYNOTE-177 trial of Keytruda meets endpoint in microsatellite instability-high (MSI-H) cancer.- Merck Inc

Merck Inc announced that the Phase III KEYNOTE-177 trial evaluating first-line treatment of Keytruda (pembrolizumab), in patients with microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR) unresectable or metastatic colorectal cancer met one of its dual primary endpoints of progression-free survival (PFS). Based on an interim analysis conducted by an independent Data Monitoring Committee (DMC), Keytruda monotherapy demonstrated a statistically significant and clinically meaningful improvement in PFS compared with chemotherapy (investigator’s choice of mFOLFOX6 or FOLFIRI, with or without bevacizumab or cetuximab).

Based on the recommendation of the DMC, the study will continue without changes to evaluate overall survival (OS), the other dual primary endpoint. The safety profile of Keytruda in this trial was consistent with previously reported studies, and no new safety signals were identified.

Comment: these head-to-head data with Keytruda are the first time a single-agent, anti-cancer therapy, and particularly an anti-PD-1 monotherapy, achieved a statistically significant improvement in progression-free survival over chemotherapy, including the current standard of care regimen of mFOLFOX6 plus bevacizumab, in patients with MSI-H colorectal cancer.