ERBB2 and gastroesophageal junction adenocarcinoma: In attempts to validate this combination approach in HER2-targeted first-line therapy, the ongoing phase 3 KEYNOTE-811 trial (NCT03615326) is randomizing patients with advanced HER2-positive gastric or GEJ adenocarcinoma to fluoropyrimidine, platinum, and trastuzumab chemotherapy with or without the addition of pembrolizumab.