KEYNOTE-177: Phase 3, open-label, randomized study of first-line pembrolizumab (Pembro) versus investigator-choice chemotherapy for mismatch repair-deficient (dMMR) or microsatellite instability-high (MSI-H) metastatic colorectal carcinoma (mCRC).

TPS877Background: Approximately 5% of mCRCs are dMMR, leading to high levels of MSI. CRCs with MSI-H have abundant lymphocyte infiltrates and strong expression of immune checkpoints. In the phase 2...