Purpose: To determine the dose-limiting toxicity (DLT) and activity of combination with docetaxel and S-1 on unresectable gastric cancer.
Patients and methods: Docetaxel was administered intravenously on day 1 and S-1 was administered orally on days 1-14, every 3 weeks. Doses of each drug in phase I study were docetaxel 60-75 mg/m(2) and S-1 60-80 mg/m(2). A phase II study was conducted with the recommended dose (RD) based on phase I.
Results: Sixty-five patients (median age 54 years) were enrolled. The DLTs were neutropenia with fever or stomatitis. The RD was docetaxel 75 mg/m(2) and S-1 60 mg/m(2). Two patients (aged 66 and 64 years) developed septic shock during the initial part of phase II study. A phase I study at lower dose (docetaxel 60 mg/m(2) and S-1 80 mg/m(2)) was conducted for patients older than 60 years, and this dose was determined as the RD for these patients. In the phase II study, frequent grade 3/4 toxicities were neutropenia (47%) and febrile neutropenia (26%). The overall response rate was 50% (95% CI, 35-66%) and median survival was 15.3 months (95% CI, 10.0-20.6 months).
Conclusions: Combination with docetaxel and S-1 was active against advanced gastric cancer and gave manageable toxicities.