A multi-institution phase II study of gemcitabine/cisplatin/S-1 (GCS) combination chemotherapy for patients with advanced biliary tract cancer (KHBO 1002)

Gemcitabine/cisplatin combination therapy has been the standard palliative chemotherapy for patients with advanced biliary tract cancer (BTC). We aimed to evaluate the efficacy and safety of adding S-1 to gemcitabine/cisplatin combination therapy for patients with advanced BTC. Patients with histologically or cytologically confirmed unresectable or recurrent BTC were eligible for inclusion. The primary end point was overall survival. Based on the results of our preceding phase I study, gemcitabine and cisplatin were administered intravenously at doses of 1,000 or 25 mg/m(2), respectively, on day 1, and oral S-1 was administered daily at a dose of 80 mg/m(2) on days 1-7 every 2 weeks. This study was registered with ClinicalTrials.gov (NCT01284413) and the UMIN Clinical Trials Registry (ID 000004468). Fifty patients enrolled between October 2011 and August 2012 were evaluated. After a median follow-up of 15.1 months (range 2.4-24.4 months), the median overall survival time was 16.2 months [95 % confidence interval (CI) 10.2-22.2 months], and the one-year overall survival rate was 59.9 % (95 % CI 46.2-73.5 %). The grade 3-4 hematological toxicities were as follows: neutropenia (32 %), anemia (32 %), thrombocytopenia (10 %), and febrile neutropenia (4 %). The common grade 3-4 non-hematological toxicities were biliary tract infection (14 %), anorexia/nausea (10 %), and fatigue (8 %). Gemcitabine/cisplatin/S-1 combination chemotherapy offered a promising survival benefit with manageable toxicity in patients with advanced BTC. A randomized phase III trial to investigate the efficacy of this regimen compared to gemcitabine/cisplatin combination therapy in patients with advanced BTC is now underway (UMIN000014371/NCT02182778).