335TiP Open-label, multinational, multicenter, phase IIIb/IV study of trastuzumab deruxtecan (T-DXd) in patients with or without baseline brain metastasis with previously treated advanced/metastatic human epidermal growth factor receptor 2–positive breast cancer (HER2+ BC): DESTINY-Breast12

Abstract

HER2+ BC is associated with a high incidence (up to 50%) of brain metastasis (BM) despite advances in treatment (Freedman et al. J Clin Oncol. 2019). Although several agents have been studied in patients (pts) with HER2+ BC with BM, an unmet medical need remains due to the poor prognosis in this pt population. In DESTINY-Breast01, T-DXd demonstrated efficacy in the overall population and preliminary efficacy in a pt subgroup with stable BM, with a confirmed objective response rate (ORR) of 61.4% and an extracranial confirmed ORR by independent central review (ICR) of 58.3%, respectively, median progression-free survival (PFS) of 19.4 and 18.1 mo, respectively, and median duration of response (DOR) of 20.8 and 16.9 mo, respectively (Modi S et al.