LBA55 Primary analysis of a phase II single-arm trial of trastuzumab deruxtecan (T-DXd) in western patients (Pts) with HER2-positive (HER2+) unresectable or metastatic gastric or gastroesophageal junction (GEJ) cancer who progressed on or after a trastuzumab-containing regimen

Overexpression and/or amplification of HER2 occurs in ∼20% of gastric or GEJ cancers. In DESTINY-Gastric01, the HER2-targeted antibody-drug conjugate T-DXd improved response and overall survival vs physician’s choice irinotecan/paclitaxel in pts from Japan/Korea with locally advanced or metastatic HER2+ gastric/GEJ cancer who progressed on ≥2L therapy including trastuzumab. Here, we report data from the single-arm, phase 2 DESTINY-Gastric02 trial, the first 2L study of T-DXd in Western pts with HER2+ gastric/GEJ cancer.