The safety and efficacy of recombinant human adenovirus 5 injection (H101) intraperitoneal administration combined with tislelizumab and platinum, fluorouracil-based drugs in the treatment of gastric cancer with peritoneal metastasis: an open-label, single-arm, prospective clinical study protocol.

This prospective, open-label, single-arm, exploratory clinical trial aims to evaluate the safety and efficacy of intraperitoneal perfusion of recombinant human adenovirus type 5 (H101) in combination with systemic tislelizumab and platinum-fluorouracil chemotherapy (XELOX) for patients with gastric adenocarcinoma and peritoneal metastasis. A total of 20 eligible patients, with or without ascites, will be enrolled to receive intraperitoneal H101 followed by systemic tislelizumab (200 mg, Q3W) and the XELOX regimen (oxaliplatin and capecitabine). The co-primary endpoints are the safety profile and the 1-year overall survival (OS) rate, with an efficacy target of approximately 70%. Secondary endpoints include progression-free survival (PFS), radiological response per RECIST 1.1, and changes in ascites volume and Peritoneal Carcinomatosis Index (PCI). As this is a study protocol, clinical results will be reported upon trial completion. If this triple-combination regimen demonstrates acceptable safety and a promising OS rate, it will provide preliminary evidence to support the further development of this multimodal approach for a high-risk population with limited therapeutic options.Clinical trial registration: chiCTR2500107607.