Sonesitatug Vedotin in Combination With Capecitabine With or Without Rilvegostomig in Participants With Advanced or Metastatic Gastric, Gastroesophageal Junction, or Esophageal Adenocarcinoma Expressing Claudin18.2

The purpose of this Phase III study is to evaluate the efficacy and safety of sonesitatug vedotin in combination with capecitabine with or without rilvegostomig in 1L CLDN18.2-positive, HER2-negative gastric, GEJ, and esophageal adenocarcinoma, and the clinical performance of the investigation in vitro diagnostics (IVDs). The study will include 2 cohorts to provide a treatment option for all participants that are HER2-negative and CLDN18.2-positive. Cohort 1 will evaluate sonesitatug vedotin in combination with rilvegostomig with capecitabine in participants who are CLDN18.2-positive and programmed death-ligand 1 (PD-L1) positive. Cohort 2 will evaluate sonesitatug vedotin in combination with capecitabine in participants who are CLDN18.2-positive and PD-L1 negative or immune checkpoint inhibitor (ICI) ineligible.