Phase II Study Comparing Perioperative Toripalimab With or Without S-1 Plus Oxaliplatin Chemotherapy for dMMR Locally Advanced Gastric or Esophagogastric Junction Adenocarcinoma

What this Trial Is About

Researchers are conducting a phase II randomized controlled trial to compare different treatments for adults with mismatch repair deficient dMMR locally advanced adenocarcinoma of the stomach or esophagogastric junction. This study aims to evaluate the effectiveness of chemotherapy combined with toripalimab, toripalimab alone, and chemotherapy alone in this patient group. Participants have a confirmed diagnosis and meet specific cancer staging criteria. The trial includes three groups one receiving toripalimab plus chemotherapy SOX regimen S-1 and oxaliplatin, one receiving toripalimab alone, and one receiving chemotherapy alone. Treatments are given in cycles of 21 days, with three cycles before surgery and three cycles after surgery. Toripalimab is administered as a 240 mg intravenous infusion on the first day of each cycle, while chemotherapy includes oxaliplatin infusion and oral S-1 taken twice daily for two weeks followed by a rest period. Participants will be involved from enrollment through surgery and follow-up, lasting up to approximately 36 months for primary outcome assessment and up to 72 months for survival outcomes. Researchers will monitor pathological response rates, overall survival, progression-free survival, and adverse events. Assessments include clinical evaluations, laboratory tests, and collection of surgical specimens for biomarker analysis. Safety monitoring continues up to 90 days after the last treatment dose.

Perioperative Chemotherapy Plus Toripalimab for dMMR Locally Advanced Gastric or Esophagogastric Junction Adenocarcinoma