ERBB2 and gastroesophageal junction adenocarcinoma: In KEYNOTE-859, pembrolizumab plus chemotherapy significantly prolonged overall survival in patients with locally advanced or metastatic HER2-negative gastric or gastroesophageal junction adenocarcinoma compared to chemotherapy alone (12.9 months vs. 11.5 months; HR 0.78 [49], and has therefore met the requirements for first-line treatment recommendations [50].