297P First-line (1L) trastuzumab deruxtecan (T-DXd) 5.4 mg/kg + fluoropyrimidine (FP) + pembrolizumab (pembro) in advanced HER2+ gastric cancer (GC), gastroesophageal junction adenocarcinoma (GEJA), or esophageal adenocarcinoma: updated results from DESTINY-Gastric03 (DG-03) Part 2F