A multicenter phase II study of S-1 for gemcitabine-refractory biliary tract cancer

Gemcitabine (GEM)-based chemotherapy has been used worldwide as the first-line treatment for advanced biliary tract cancer (BTC). However, no standard regimens have been established yet for patients with GEM-refractory BTC. A previous phase II trial of S-1 as a first-line treatment in patients with advanced BTC revealed promising activity of this drug. The present study was conducted to evaluate the efficacy and safety of S-1 in patients with GEM-refractory BTC.

The subjects were patients with pathologically proven BTC who had shown disease progression while receiving GEM-based chemotherapy. Each treatment cycle consisted of administration of S-1 orally at the dose of 40 mg/m(2) twice daily for 28 days, followed by a rest period of 14 days. The primary endpoint of this study was objective response, and the secondary endpoints were the toxicity, progression-free survival (PFS), and overall survival (OS).

Forty patients were assessed for efficacy and safety from 8 hospitals in Japan between June 2007 and September 2008. There were 3 cases of confirmed partial response (7.5 %) and 22 patients (55 %) of stable disease. The median PFS and OS were 2.5 and 6.8 months, respectively. Toxicity was generally mild, and the most common grade 3 or 4 toxicities were anorexia (10.0 %), anemia (7.5 %), mucositis (7.5 %), hypoalbuminemia (5.0 %), and pneumonia (5.0 %). There were no treatment-related deaths.

Monotherapy with S-1 was well tolerated, but showed modest efficacy in patients with GEM-refractory BTC.