Camrelizumab plus SOX chemotherapy as adjuvant therapy for pathological stage III gastric or gastroesophageal junction adenocarcinoma: a prospective, multicenter, single-arm, phase II trial

Immune checkpoint inhibitors have shown promising results in the treatment of advanced gastric or gastroesophageal junction (G/GEJ) adenocarcinoma. To evaluate the safety and efficacy of camrelizumab combined with S-1 plus oxaliplatin chemotherapy in the postoperative setting for pathological stage III (pStage III) G/GEJ adenocarcinoma. This study was a prospective, multicenter, single-arm, phase II trial. Patients with pStage III G/GEJ adenocarcinoma were enrolled, receiving camrelizumab (200 mg), followed by oxaliplatin (130 mg/m2), both administered on day 1 of each 21-day cycle, and tegafur-gimeracil-oteracil potassium capsules (40-60 mg, twice daily) for 2 weeks, followed by a 7-day rest period. A total of eight treatment cycles were planned. The primary endpoints were the incidence of any-grade and grade 3 or 4 adverse events. The secondary endpoints were disease-free survival (DFS), overall survival (OS), and treatment completion rate. Between September 2020 and March 2023, 52 patients were enrolled at three medical centers in Zhejiang Province, China. All 52 patients (100%) experienced treatment-related adverse events (TRAEs). Grade 3 or higher TRAEs were reported in 35 patients (67.3%). Events occurring in >10% of the patients included decreased neutrophil count, neutropenia, leukopenia, thrombocytopenia, and anemia. Eleven (21.2%) patients experienced TRAEs that led to the interruption or discontinuation of camrelizumab, including rash (1), hypothyroidism (1), hyperkalemia (1), interstitial pneumonia (2), cystitis or urethritis (2), and reactive cutaneous capillary endothelial proliferation (4). The actual 2-year DFS and OS rates were 82.4% and 86.3%, respectively, whereas the estimated 3-year DFS and OS rates were 69.1% and 71.3%, respectively. Camrelizumab combined with chemotherapy has a manageable and tolerable safety profile as an adjuvant treatment for pStage III G/GEJ adenocarcinoma. However, careful patient selection is necessary to identify patients most likely to benefit from combination therapy. ClinicalTrials.gov registry: NCT04515615; Date of registration: August 14, 2020; Weblink: https://clinicaltrials.gov/study/NCT04515615.