Global Phase 3 Study of ASP2138 with Chemotherapy and Pembrolizumab for Adults with Advanced HER2-negative, CLDN18.2-positive Gastric or Gastroesophageal Junction Cancer

What this Trial Is About

Researchers are investigating the use of ASP2138, combined with chemotherapy and pembrolizumab, for adults with advanced gastric or gastroesophageal junction GEJ cancer that is HER2-negative and CLDN18.2-positive. This Phase 3 trial focuses on people whose cancer has spread nearby or to other parts of the body and cannot be removed by surgery. The study aims to find out if adding ASP2138 to standard treatments helps control the cancer and improves survival compared to placebo. Participants will be randomly assigned to one of two groups one group will receive ASP2138 by subcutaneous injection plus chemotherapy and pembrolizumab, while the other group will receive placebo injections with chemotherapy, with or without pembrolizumab. Treatments are given in 42-day cycles with specific dosing schedules depending on the chemotherapy regimen used. Participants will continue treatment until their cancer worsens, medical issues arise, or study rules require stopping. Throughout the study, participants will have regular safety checks and tumor scans to monitor disease status. Researchers will measure how long participants live without their cancer progressing and overall survival up to 54 months. Other assessments include response rates, adverse events, quality of life questionnaires, lab tests, and immune response markers. The study includes ongoing monitoring to gather comprehensive information on treatment effects and safety.

A Study of ASP2138 Together With Chemotherapy and Pembrolizumab in Adults With Gastric Cancer