Phase II trial of S-1 in combination with gemcitabine for chemo-na⟨ve patients with locally advanced or metastatic pancreatic cancer

We performed a phase II study of combination chemotherapy with S-1 plus gemcitabine for treating chemo-na < ve patients with unresectable pancreatic cancer to evaluate the efficacy and toxicity. Patients with histologically confirmed unresectable pancreatic cancer were eligible. The treatment consisted of S-1 (40 mg/m(2) p.o. b.i.d. from D1 to 14) and gemcitabine (1,250 mg/m(2) on D1 and 8), repeated every 3 weeks. Thirty-two patients were enrolled between March 2005 and December 2007. No complete response was observed and a partial response was observed in 14 patients (44.0%), stable disease in eight patients (25.0%), and progressive disease in eight patients (25.0%). The median time to progression was 4.92 months (95% CI: 4.16-5.67 months), and the median overall survival was 7.89 months (95% CI: 5.96-9.82 months). The survival duration was significantly longer for the patients with a good performance status compared with that of the patients with a poor performance status. The major toxicities were grade 3-4 neutropenia (9, 28.1%), grade 3/4 thrombocytopenia (5, 15.6%), and grade 3 diarrhea (5, 15.6%). The combination chemotherapy of S-1 and gemcitabine showed promising antitumor activity and manageable toxicities, and especially for the good performance status patients with unresectable pancreatic cancer.