A Phase 1b/2 Study of T-DXd Combinations in HER2-positive Metastatic Breast Cancer

This study is modular in design allowing assessment of safety, tolerability and anti-tumour activity of T-DXd in combination with other anti-cancer agents. Combination-treatment modules will have 2 parts: a dose-finding phase (Part 1), and a dose expansion phase (Part 2); the recommended Phase 2 dose (RP2D) determined in Part 1 will be used for the dose-expansion in Part 2. The target population of interest in this study is patients with HER2-positive (as per ASCO/CAP 2018 guidelines) advanced/MBC inclusive of patients with active and stable brain metastases. Part 1 of each module will enroll patients with locally assessed HER2-positive advanced/MBC in second-line or later patients. Part 2 of each module will enroll patients with locally assessed HER2-positive breast cancer who have not received prior treatment for advanced/metastatic disease.