Pembrolizumab for HER2-Positive Gastric or Gastro-Esophageal Junction Cancer: More Interim Results from KEYNOTE-811

In a preplanned interim analysis of the industry-sponsored, placebo-controlled, randomized KEYNOTE-811 trial in patients with HER2-positive esophagogastric adenocarcinoma, adding pembrolizumab to trastuzumab and chemotherapy led to a marked increase in response to therapy — and to accelerated FDA approval of pembrolizumab (NEJM JW Oncol Hematol Sept 2020 and Nature 2021; 600:727). Now, investigators report updates in response, progression-free survival (PFS), and overall survival (OS).

All patients received pembrolizumab (200 mg) or placebo plus trastuzumab in three-week cycles, combined with either capecitabine/oxaliplatin or a 5-day infusion of 5-FU plus cisplatin. Of the 698 treated patients, 85% received capecitabine/oxaliplatin, 67% had…