Randomized controlled study of gemcitabine plus S-1 combination chemotherapy versus gemcitabine for unresectable pancreatic cancer

Purpose The aim of this study was to evaluate efficacy and safety of gemcitabine plus S-1 (GS) combination chemotherapy in patients with unresectable pancreatic cancer. Methods Patients were randomly assigned to receive GS (oral S-1 60 mg/m 2 daily on days 1–15 every 3 weeks and gemcitabine 1,000 mg/m 2 on days 8 and 15) or gemcitabine (1,000 mg/m 2 on days 1, 8, and 15 every 4 weeks). The primary endpoint was progression-free survival (PFS). Results One hundred and one patients were randomly assigned. PFS was significantly longer in the GS arm with an estimated hazard ratio (HR) of 0.65 (95 % CI 0.43 – 0.98; P = 0.039; median 5.3 vs 3.8 months). Objective response rate (ORR) was also better in the GS arm (21.6 vs 6 %, P = 0.048). Median survival was 8.6 months for GS and 8.6 months for GEM (HR 0.93; 95 % CI 0.61 – 1.41; P = 0.714). Grade 3–4 neutropenia (44 vs 19.6 %, P = 0.011) and thrombocytopenia (26 vs 8.7 %, P = 0.051) were more frequent in the GS arm. Conclusions GS therapy improved PFS and ORR with acceptable toxicity profile in patients with unresectable pancreatic cancer.