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

Purpose: 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. Methods: 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/m² was intravenously given over 30 min on days 1 and 8, while S-1 at a dose of 40 mg/m² 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. Results: 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%). Conclusions: Gemcitabine and S-1 combination chemotherapy was effective and tolerable in patients with unresectable pancreatic cancer.