ERBB2 and esophageal adenocarcinoma: The DESTINY-Gastric03 (DG-03) trial is a multicenter, open-label, phase Ib/II study designed to evaluate the safety and efficacy of T-DXd monotherapy and combination regimens in patients with HER2-expressing (HER2+ and HER2-low) unresectable, locally advanced, or metastatic gastric cancer, GEJA, or esophageal adenocarcinoma.