Trastuzumab deruxtecan versus treatment of physician’s choice in previously treated Asian patients with HER2-low unresectable/metastatic breast cancer: subgroup analysis of the DESTINY-Breast04 study
Toshinari Yamashita, Joohyuk Sohn, Eriko Tokunaga, Naoki Niikura, Yeon Hee Park, Keun Seok Lee, Yee Soo Chae, Binghe Xu, Xiaojia Wang, Seock‐Ah Im, Wěi Li, Yen‐Shen Lu, Cecilia Orbegoso Aguilar, Soichiro Nishijima, Yuji Nishiyama, Masahiro Sugihara, Shanu Modi, Junji Tsurutani
Abstract
BACKGROUND: In the global phase 3 DESTINY-Breast04 study (NCT03734029), the anti-human epidermal growth factor 2 (HER2) antibody-drug conjugate trastuzumab deruxtecan (T-DXd) demonstrated a statistically significant improvement in progression-free survival (PFS) and overall survival (OS), with manageable safety compared with treatment of physician's choice (TPC) in patients with HER2-low metastatic breast cancer (mBC) who had received 1-2 prior lines of chemotherapy. METHODS: This subgroup analysis examined the efficacy and safety of T-DXd versus TPC in 213 patients from Asian countries and regions who were enrolled in the DESTINY-Breast04 trial and randomized to T-DXd (n = 147) or TPC (n = 66). RESULTS: Median PFS with T-DXd and TPC was 10.9 and 5.3 months, respectively, in Asian patients with hormone receptor-positive mBC, and 10.9 and 4.6 months, respectively, in the overall Asian population. In both populations, median OS was not reached with T-DXd and was 19.9 months with TPC. The objective response rate was higher with T-DXd versus TPC in all Asian patients. Median treatment duration was 8.4 months with T-DXd and 3.5 months with TPC. The most common grade ≥ 3 drug-related treatment-emergent adverse events in Asian patients treated with T-DXd were neutropenia (16.3%), anemia (12.9%), and leukopenia (11.6%); the incidences of neutropenia and leukopenia were higher with TPC versus T-DXd. Adjudicated drug-related interstitial lung disease or pneumonitis with T-DXd was 14.3%; the majority of events were grade 1-2. CONCLUSIONS: T-DXd demonstrated clinically meaningful survival benefits versus TPC in Asian HER2-low mBC patients, regardless of hormone receptor status, with no new safety signals. CLINICAL TRIAL REGISTRATION NUMBER: ClinicalTrials.gov, NCT03734029.