Strong Pathologic Complete Response to Immunotherapy in MSI-High Esophagogastric Cancer

Immune checkpoint inhibitors have substantial activity across the spectrum of microsatellite-instability–high (MSI-H) cancers. Superior efficacy of these agents over chemotherapy was demonstrated recently for first-line treatment of MSI-H metastatic colorectal cancer. Recent studies also indicate high rates of clinical and pathologic complete response to anti-PD-1 therapy in locally advanced colon and rectal cancers. Investigators from France now report results from the GERCOR NEONIPIGA study, a single-arm phase 2 trial evaluating locally advanced MSI-H esophagogastric adenocarcinoma. Patients received preoperative therapy with ipilimumab given once every 6 weeks and nivolumab given every 2 weeks, both for 12 weeks total, followed by surger…