DESTINY-Breast08: A Phase Ib Study of Trastuzumab Deruxtecan in Combination with Other Anticancer Therapies in Patients with HER2-Low Metastatic Breast Cancer

Abstract

Purpose: Establish the safety, tolerability, and preliminary activity of trastuzumab deruxtecan (T-DXd) in combination with other anticancer therapies in human epidermal growth factor receptor 2 (HER2)–low metastatic breast cancer (mBC). Patients and Methods: DESTINY-Breast08 was a two-part, open-label, multicenter, phase Ib study. Patients with locally confirmed HER2-low mBC received T-DXd plus capecitabine, durvalumab + paclitaxel, capivasertib, anastrozole, or fulvestrant. Eligibility criteria for hormone receptor status varied across modules and between study parts. Primary objectives were safety/ tolerability and determining recommended phase II doses (RP2D); secondary endpoints include..