ERBB2 and gastric cancer: The phase 3 CheckMate 649 established superior overall survival of nivolumab in combination with chemotherapy (NIVO + chemo) compared with chemotherapy (chemo) alone as a first-line treatment for patients with Her2-negative advanced gastric cancer, gastroesophageal junction cancer, and esophageal adenocarcinoma (GC/GEJC/EAC).