A Prospective, Multicenter, Single-Arm Phase II Exploratory Study of Serplulimab Combined With Oncolytic Virus H101, Short-Course Radiotherapy, and XELOX Chemotherapy as Total Neoadjuvant Treatment for Locally Advanced (cT1-3N0M0) Rectal Cancer

This study aims to evaluate the safety and effectiveness of a combination treatment including a PD-1 inhibitor (serplulimab), oncolytic virus H101, short-course radiotherapy, and XELOX chemotherapy as total neoadjuvant therapy in patients with locally advanced low rectal cancer (cT1-3N0M0). In this prospective, multicenter, single-arm phase II study, eligible patients will receive a standardized treatment regimen consisting of intratumoral injection of oncolytic virus H101, short-course radiotherapy, chemotherapy, and immunotherapy over multiple cycles. Tumor response will be assessed using imaging, endoscopy, and clinical evaluation after completion of treatment. The primary objective is to determine the 1-year clinical complete response rate. Secondary outcomes include tumor response rate, organ preservation rate, survival outcomes, and treatment safety. The results of this study may help improve treatment strategies for rectal cancer, increase the rate of complete response, and provide more opportunities for organ preservation while maintaining safety.