Pembrolizumab Clears Tumors in 58% of MSI-H Cancers, 47% Alive at 10 Years

PD-1 inhibitors, like pembrolizumab, showed strong efficacy in dMMR/MSI-H cancers. KEYNOTE-016 (NCT01876511), a multicenter phase 2 trial, gave pembrolizumab 2 mg/kg Q2W to 88 adults with heavily pre-treated dMMR/MSI-H cancers—41 colorectal and 47 non-CRC (endometrial, pancreatic, small-intestine, gastro-esophageal, biliary, ampullary, others). After a median 100 months’ follow-up for survivors, investigator-assessed ORR was 58% (26% CR, 32% PR). Median PFS reached 34.9 months and median OS 80.8 months, while landmark OS remained 55% at 3 y, 54% at 5 y, and 47% at 10 y—similar across CRC and non-CRC cohorts (ORR 56% vs 60%).