A Phase 3, Double-blind, Randomized Study of Zolbetuximab with Pembrolizumab and Chemotherapy in Adults with HER2-negative, Claudin 18.2-positive, PD-L1-positive Locally Advanced or Metastatic Gastric or Gastroesophageal Junction Adenocarcinoma

What this Trial Is About

Researchers are evaluating zolbetuximab combined with pembrolizumab and chemotherapy for adults with stomach or gastroesophageal junction GEJ cancer that is locally advanced, unresectable, or metastatic. This study focuses on cancers that do not have the HER2 protein but do express Claudin 18.2 and PD-L1 proteins. The goal is to find out how long people live after receiving zolbetuximab with pembrolizumab and chemotherapy compared to a placebo with the same treatments. Participants will receive treatment in 6-week cycles. The study treatment includes zolbetuximab or a placebo given by infusion every 2 or 3 weeks, combined with pembrolizumab infusions every 3 or 6 weeks. Chemotherapy options include CAPOX capecitabine tablets twice daily and oxaliplatin infusion or mFOLFOX6 infusions of oxaliplatin, folinic acid, and 5-fluorouracil. After several cycles, participants may receive parts of the chemotherapy alone. Treatment continues until the cancer worsens, side effects prevent continuation, or another cancer treatment is needed. Pembrolizumab may be given for up to 2 years. During the study, participants will visit the clinic for treatment and health checks, including scans to monitor cancer changes. Researchers will watch for medical problems related to zolbetuximab and other treatments. Tumor samples may be collected if treatment stops because of cancer progression. After stopping treatment, participants will have continued health checks and scans every 9 to 12 weeks, plus telephone check-ins every 3 months. The frequency of visits depends on each persons health and treatment status.

A Study of Zolbetuximab Together With Pembrolizumab and Chemotherapy in Adults With Gastric Cancer