Efficacy of Tirellizumab Combined With Oral, Intravenous and Abdominal Chemotherapy in Peritoneal Metastatic Gastric/Gastroesophageal Junction Adenocarcinoma

For peritoneal metastatic gastric/gastroesophageal junction adenocarcinoma (cT3-4NanyM1), PD-1 antibody combined with chemotherapy and hyperthermic intraperitoneal chemotherapy (HIPEC) can downstage tumor stage, increase the conversion resection rate, and may improve the long-term survival. Tislelizumab, an anti-PD-1 antibody, has recently been proved in the first- and second-line standard treatment for advanced or metastatic gastric or gastro-oesophageal junction adenocarcinoma.In the subgroup analysis of RATIONALE-305 trial, tislelizumab also showed good efficacy in gastric/gastroesophageal junction adenocarcinoma patients with peritoneal metastasis. Combination of tirellizumab,SOX and HIPEC for peritoneal metastatic gastric/gastroesophageal junction adenocarcinoma could be a novel therapeutic strategy to increase response rate and therapeutic efficacy. This study is a monocenter, single-arm phase 2 clinical trial to evaluate tolerability, safety and efficacy of perioperative tirellizumab in combination with SOX and HIPEC in peritoneal metastatic gastric/gastroesophageal junction adenocarcinoma.

Inclusion Criteria: Signed informed consent Patients age 18-75 years Histologically CT/MRI confirmed cT3-4NanyM1 gastric or GEJ adenocarcinoma; Peritoneal metastasis was confirmed by laparoscopy (with or without Krukenberg tumor ) The degree of peritoneal metastasis ≤P1b or PCI≤13 points ECOG 0-1, no surgery contraindications; Expected survival ≥3 months; Exclusion Criteria: Prior chemotherapy, radiotherapy, surgery for gastric cancer; Signs of other distant metastases (e.g., liver, lung, bone, supraclavicular lymph, etc.) Significant cardiovascular disease Major surgical procedure within 4 weeks prior to initiation of study treatment Current treatment with anti-viral therapy or HBV Pregnancy or breastfeeding History of malignancy within 5 years prior to screening Present or history of any autoimmune disease or immune deficiency Prior therapy with a PD-1, anti-PD-Ligand 1 (PD-L1) or CTLA-4 agent There are active gastric and duodenal ulcers, ulcerative colitis and other gastrointestinal diseases, or active bleeding in unresectable tumors Poorly controlled hypertension or diabetes