KEYNOTE-177 — Pembrolizumab Versus Chemotherapy for Microsatellite Instability-High/Mismatch Repair-Deficient Metastatic Colorectal Cancer

Phase 3 · 2020 · Colorectal Cancer

Design

Open-label trial randomizing untreated MSI-H/dMMR metastatic CRC 1:1 to first-line pembrolizumab or investigator-choice FOLFOX/FOLFIRI +/- biologic.

Population

Treatment-naive metastatic colorectal cancer with confirmed MSI-high or mismatch-repair-deficient status.

Primary Endpoint

progression-free survival (PFS) and overall survival (OS)

Key Result

Median PFS 16.5 vs 8.2 months (HR 0.60); durable responses with roughly half the grade 3+ toxicity of chemotherapy.

Guideline Impact

NCCN category 1 / FDA-approved first-line for MSI-H/dMMR mCRC