140P Prevalence of claudin-18 isoform 2 (CLDN18. 2) positivity in locally advanced (LA) unresectable or metastatic gastric or gastroesophageal junction (mg/GEJ) adenocarcinoma in patients (pts) in the Asia region: Phase III SPOTLIGHT and GLOW studies

摘要: BackgroundNew therapies are needed for pts with LA unresectable or mG/GEJ adenocarcinoma. CLDN18. 2 is a novel validated target expressed in healthy gastric mucosa, often retained in G/GEJ tumor cells. The phase 3 SPOTLIGHT (NCT03504397) and GLOW (NCT03653507) studies demonstrated clinically meaningful and statistically significant improvement in progression-free and overall survival with first-line (1L) zolbetuximab (anti-CLDN18. 2)+ chemotherapy (mFOLFOX6 or CAPOX, respectively) vs placebo+ chemotherapy in pts with CLDN18. 2+/HER2− disease. We report the biomarker analysis of pts in the Asia region (Japan, Malaysia, South Korea, Taiwan, Thailand).MethodsPts with LA unresectable or mG/GEJ adenocarcinoma were screened for CLDN18. 2 status by immunohistochemistry (IHC) during screening. Tumors with≥ 75% tumor cells with moderate-to-strong membranous CLDN18 …