Trastuzumab deruxtecan versus trastuzumab emtansine for HER2-positive mBC: subgroup analyses from DESTINY-Breast03

The multinational phase 3 DESTINY-Breast03 trial compared trastuzumab deruxtucan (T-DXd) versus trastuzumab emtansine (T-DM1) for HER2-positive metastatic breast cancer previously treated with trastuzumab and taxane. Primary analysis of the trial found a clinical meaningful and statistically significant PFS benefit with T-DXd over T-DM1 (median not reached versus 6.8 months; HR 0.28; p=7.8 x 10^-22). Exploratory subgroup analyses found consistent benefit with T-DXd over T-DM1 across subgroups: HR positive and negative, prior pertuzumab or no prior pertuzumab, 0-1 prior lines of therapy or ≥2 prior lines of therapy, visceral disease or no visceral disease, and brain metastases at baseline and no brain metastases at baseline (abstract GS3-01).