A Study of Trastuzumab Deruxtecan (T-DXd) Versus Trastuzumab Emtansine (T-DM1) in High-risk HER2-positive Participants With Residual Invasive Breast Cancer Following Neoadjuvant Therapy (DESTINY-Breast05)

This study will examine trastuzumab deruxtecan (T-DXd) versus trastuzumab emtansine (T-DM1) in patients with HER2-positive primary BC who have residual invasive disease in breast or axillary lymph nodes with higher risk of recurrence, which includes patients who were inoperable at disease presentation or had pathological node-positive status after neoadjuvant therapy. The primary objective is to compare invasive disease-free survival (IDFS) between T-DXd and T-DM1 treatment arms in this population. The key secondary objective of the study is to evaluate disease-free survival (DFS).