In The Lancet, Yelena Y Janjigian and colleagues1 recently published the results of the interim analyses of the KEYNOTE-811 trial, comparing first-line pembrolizumab plus trastuzumab and chemotherapy with placebo plus trastuzumab and chemotherapy for advanced HER2-positive gastric or gastro-oesophageal junction adenocarcinoma. In The Lancet Oncology, Sun Young Rha and colleagues2 published the final results of the KEYNOTE-859 trial, comparing first-line pembrolizumab plus chemotherapy with placebo plus chemotherapy for advanced HER2-negative gastric or gastro-oesophageal junction adenocarcinoma.