Short-term efficacy and safety of recombinant human adenovirus type 5 combined with PD-1 immune checkpoint inhibitors and SOX regimen in neoadjuvant therapy of locally advanced gastric cancer: a retrospective study.

Background: To evaluate the short-term efficacy and safety of recombinant human adenovirus type 5 (H101) combined with S-1 plus oxaliplatin, PD-1 immune checkpoint inhibitors(SOXP regimen) in the neoadjuvant treatment of patients with locally advanced gastric cancer (LAGC). Evaluate the safety of H101 in the treatment of gastric cancer via interventional perfusion administration. Methods: A retrospective study was conducted, enrolling patients with LAGC who received H10 combined with the SOXP regimen at The Affiliated Hospital of Guizhou Medical University between January 1, 2025, and August 30, 2025. During the first cycle of neoadjuvant therapy, H101 was administered via interventional perfusion chemotherapy targeting the gastric cancer. After patients completed two cycles of neoadjuvant treatment, tumor downstaging was assessed, followed by surgical intervention. The primary endpoint of the study was the postoperative pathological response rate (pCR); secondary endpoints included the objective response rate (ORR), duration of response (DOR), and the incidence of adverse reactions. Results: A total of 25 patients were included in the analysis. Among them, 8 patients (32%) achieved a complete response (CR), 16 patients (64%) achieved a partial response (PR), and 1 patient (4%) achieved stable disease (SD). The objective response rate (ORR) and disease control rate (DCR) were 96% and 100%, respectively, with an R0 resection rate of 100%. In terms of pathological response evaluation by tumor regression grade (TRG), 10 patients (40%) achieved grade 3, 14 patients (56%) achieved grade 2, and 1 patient (4%) achieved grade 1. The pathological complete response (pCR) rate was 40%. Most adverse events were mild to moderate and manageable, and no grade 4 adverse events were observed. Conclusions: This retrospective study indicates that the combination of H101 with the SOXP regimen exhibits promising short-term efficacy in the neoadjuvant treatment of LAGC, characterized by high ORR, DCR, R0 resection rate, and pCR rate. The preliminary evaluation shows that H101 administered via interventional therapy is safe in the treatment of LAGC. Additionally, the treatment-related toxicities are well-tolerated, supporting the potential clinical value of this therapeutic strategy for LAGC patients.