Phase II study of S-1 plus oxaliplatin 130 mg/m 2 in Japanese patients with advanced gastric cancer

Purpose Although oxaliplatin 130 mg/m 2 every 3 weeks was approved for advanced gastric cancer in Japan, data regarding S-1 plus oxaliplatin 130 mg/m 2 (SOX130) are limited in Japanese patients with advanced gastric cancer. We investigated the feasibility and safety of SOX130 in Japanese patients with advanced gastric cancer. Methods Patients with unresectable or recurrent gastric adenocarcinoma, no previous chemotherapy, and Eastern Cooperative Oncology Group Performance Status of 0–1 were treated with SOX130. The primary endpoint was the 3-cycle completion rate, defined as the proportion of patients who completed the first three cycles with ≥ 80% relative dose intensity of oxaliplatin. Results Twenty-five patients were enrolled from April 2015 to 2016. The 3-cycle completion rate was 72.0% (90% confidence interval: 53.8–86.1), which was higher than the predetermined threshold rate of 50%. With the median number of cycles being 6 (range, 1–19+), grade 3 or 4 adverse events occurred in 10 patients (40%). Major grade 3 adverse events were anorexia (24%), thrombocytopenia (16%), and neutropenia (12%). No febrile neutropenia or treatment-related deaths occurred. Among 12 patients with measurable lesions, the overall response rate was 58.3%. Median progression-free and overall survival were 5.7 months (95% confidence interval 2.9–8.5) and 13.1 months (95% confidence interval 7.4–19.0), respectively. Conclusion Results indicated that SOX130 was feasible in Japanese patients with advanced gastric cancer.