NCT04784715 2026-05-22Trastuzumab Deruxtecan (T-DXd) With or Without Pertuzumab Versus Taxane, Trastuzumab and Pertuzumab in HER2-positive Metastatic Breast Cancer (DESTINY-Breast09)AstraZenecaPhase 3 Active not recruiting1,157 enrolled 1 FDA