Phase 3 Trial of Trastuzumab Deruxtecan, a HER2-directed topoisomerase I inhibitor ADC

This randomized open-label trial compares a triplet regimen of trastuzumab deruxtecan (HER2-directed topoisomerase I inhibitor ADC) plus fluoropyrimidine and pembrolizumab with platinum-based chemotherapy plus trastuzumab and pembrolizumab, and an exploratory arm omitting pembrolizumab, in treatment-naïve patients with unresectable advanced/metastatic HER2-positive gastric or GEJ adenocarcinoma. Sponsored by Daiichi Sankyo, the study evaluates efficacy and safety across multiple global sites.