A multicenter phase II study of gemcitabine and S-1 combination chemotherapy in patients with unresectable pancreatic cancer

To confirm the efficacy and toxicity of gemcitabine and S-1 combination chemotherapy when used as a first-line therapy in patients with unresectable pancreatic cancer. Patients with locally advanced or metastatic or recurrent pancreatic adenocarcinoma, which was histologically or cytologically proven, with at least one measurable lesion were eligible for the study. Gemcitabine at a dose of 1,000 mg/m(2) was intravenously given over 30 min on days 1 and 8, while S-1 at a dose of 40 mg/m(2) was orally given twice daily from day 1 to 14, and the cycle was repeated every 3 weeks. The objective response rate, which was assessed according to RECIST criteria, was the primary end point. A total of 38 patients were enrolled between June 2006 and June 2007. The median number of treatment courses was 5.5 (range 1-22). Thirty-four patients were evaluable for response. Although no complete response was seen, partial responses were achieved in 11 patients, resulting in an overall response rate of 32% [95% confidence interval (CI) 17-48%]. The median response duration was 6.0 months (95% CI 4.6-8.3 months), the median time-to-progression was 5.4 months (95% CI 2.9-8.0 months), and the median overall survival was 8.4 months (95% CI 5.7-11.1 months). The major grade 3/4 hematologic toxicities were neutropenia (39.5%), leukopenia (15.8%), thrombocytopenia (2.6%), and anemia (7.9%). The major grade 3/4 non-hematologic toxicities included anorexia (10.5%), stomatitis (2.6%), rash (7.9%), fatigue (7.9%) and hyperbilirubinemia (5.3%). Gemcitabine and S-1 combination chemotherapy was effective and tolerable in patients with unresectable pancreatic cancer.