KEYNOTE-859 — Pembrolizumab Plus Chemotherapy Versus Chemotherapy in HER2-Negative Advanced Gastric or Gastroesophageal Junction Adenocarcinoma (KEYNOTE-859)

Phase 3 · 2023 · Gastric Cancer, Gastroesophageal Junction Cancer

Design

Randomized double-blind trial of pembrolizumab plus fluoropyrimidine-platinum chemotherapy versus placebo plus chemotherapy.

Population

Untreated HER2-negative locally advanced or metastatic gastric or gastroesophageal junction adenocarcinoma.

Primary Endpoint

overall survival (OS)

Key Result

OS 12.9 vs 11.5 months (HR 0.78), with greater benefit in PD-L1 CPS ≥1 and CPS ≥10 subgroups.

Guideline Impact

NCCN-listed pembrolizumab plus chemotherapy for first-line HER2-negative gastric/GEJ adenocarcinoma (preferred at higher CPS)