Patients and treatment
HER2-negative, tumor, tumors, adenocarcinoma
TUMOR, TUMORS, ADENOCARCINOMA
Between 28 November 2018 and 18 February 2022, a total of 2,333 patients with previously untreated, locally advanced unresectable or mG/GEJ adenocarcinoma were screened at 166 sites in 18 countries. CLDN18.2 tumor status was assessed in 2,104 patients, of whom 808 (38.4%) had tumors that met the cutoff for CLDN18.2 positivity (≥75% of tumor cells with moderate-to-strong CLDN18 membranous staining as determined by central immunohistochemistry using the investigational VENTANA CLDN18 (43-14A) RxDx assay). Among patients whose tumors were assessed for CLDN18.2 status, 1,701 had tumors that were HER2-negative; 729 of 1,701 (42.9%) patients had tumors that met the cutoff for CLDN18.2 positivity. Of screened patients with tumors that were HER2-negative and met the cutoff for CLDN18.2 positivity, 222 were not randomized owing to failure to meet other inclusion criteria or the patient’s decision to withdraw from the study. Ultimately, 507 patients with CLDN18.2-positive tumors were randomly assigned to receive either zolbetuximab plus CAPOX (