Phase II study of S-1 plus docetaxel as first-line treatment for older patients with advanced gastric cancer (OGSG 0902).

ABSTRACT

BACKGROUND: Although there is insufficient evidence for the treatment of older patients with advanced gastric cancer, fluorouracil combined with platinum chemotherapy has been recognized as a standard first-line treatment for such populations in Japan despite the lack of efficacy and toxicity data. METHODS: Patients aged 75 years or older with advanced gastric cancer were enrolled. S-1 plus docetaxel (docetaxel 40 mg/m2, day 1; S-1 80 mg/m2, days 1-14; q21 days) was repeated every 3 weeks. The primary endpoint was overall response rate. Secondary endpoints were safety, progression-free survival, time to treatment failure, and overall survival. The sample size was calculated as 30 under the hypothesis of an expected response rate of 40% and a threshold response rate of 20%, at a power of 90% and a two-sided alpha value of 5%. RESULTS: From February 2010 to January 2015, 31 patients were enrolled and assessed for efficacy and toxicity. The response rate was 45.2% (95% CI 27.3%-64.0%; p = 0.001) and it exceeded the expected response rate set at 40%. Median progression-free survival was 5.8 months, the 1-year survival rate was 58.1%, and the median survival time was 16.1 months. The major grade 3/4 adverse events were neutropenia (58%), febrile neutropenia (13%), anemia (10%), anorexia (10%), and fatigue (6%). CONCLUSIONS: These findings indicate that S-1 plus docetaxel as first-line treatment for older patients is feasible and that it has promising efficacy against advanced gastric cancer.