Multinational phase 3 trial of nivolumab plus ipilimumab versus nivolumab for MSI-H metastatic colorectal cancer

The multinational phase 3 CheckMate 8HW trial randomized patients with MSI-H or dMMR metastatic colorectal cancer (mCRC) across all treatment lines 2:2:1 to nivolumab plus ipilimumab, nivolumab alone, or chemotherapy. Results for the coprimary endpoint progression-free survival with nivolumab plus ipilimumab (‘combination group’; n=296) versus nivolumab alone (‘nivolumab group; n=286) have now been published. The median follow-up was 47.0 months (IQR 38.4-53.2). The median PFS was not reached in the combination group and was 39.3 months in the nivolumab group (HR 0.62; p=0.0003); treatment-related adverse events occurred in 81% versus 71%; grade 3 or 4 TRAEs occurred in 22% versus 14%; and grade 5 TRAEs in 2 patients versus 1 patient. The authors conclude that nivolumab plus ipilimumab showed superior PFS versus nivolumab across all treatment lines, with a manageable safety profile, in patients with MSI-H/dMMR mCRC.