ETCTN Phase 1 Study of Trastuzumab Deruxtecan (DS-8201a) in Combination with Azenosertib (ZN-c3) in HER2-Expressing/Amplified Cyclin E-Amplified Gastric/Gastroesophageal Junction Cancer and Other Solid Tumors with HER2 Expression Adult CIRB - Early Phase Emphasis Active Available to Open