KEYNOTE-062

KEYNOTE-062 randomised 763 patients with untreated advanced gastric or gastro-oesophageal junction adenocarcinoma expressing PD-L1 (combined positive score of 1 or more) to pembrolizumab alone, pembrolizumab plus cisplatin and a fluoropyrimidine, or chemotherapy plus placebo. The primary endpoints were overall and progression-free survival in the PD-L1-positive and high-PD-L1 (score of 10 or more) populations.

Pembrolizumab alone was non-inferior to chemotherapy for overall survival, with a larger apparent advantage at a score of 10 or more, but pembrolizumab plus chemotherapy was not superior to chemotherapy alone. Patients with microsatellite-unstable tumours, a small subgroup, did strikingly well with pembrolizumab. The trial did not change first-line practice by itself, but its subgroup findings shaped how later chemo-immunotherapy trials and approvals were read.