S-1 monotherapy as first-line treatment in patients with advanced biliary tract cancer: a multicenter phase II study.

ABSTRACT

A pilot phase II study showed S-1 monotherapy to be safe and active against biliary tract cancer (BTC). We, therefore, conducted a multicenter phase II study to evaluate the antitumor effect and safety of S-1 in previously untreated patients with advanced BTC. Eligible patients had pathologically proven, unresectable adenocarcinoma with no prior chemotherapy or radiotherapy. Patients received S-1 orally at 80 mg/m2 total daily dose divided b.i.d. for 28 days followed by 14 days of rest. Of the 41 enrolled patients, 40 were assessable. The primary tumor sites were as follows gallbladder (n = 20), extrahepatic bile duct (n = 15), and the ampulla of Vater (n = 5). One patient (2.5%) achieved a complete response, 13 patients (32.5%) had partial responses, 17 patients (42.5%) had no change, 7 patients (17.5%) had progressive disease, and 2 patients (5.0%) were not evaluable. The overall objective response rate was 35.0%. The median overall survival (median OS) was 9.4 months, and the median time to progression was 3.7 months. Grade 3 or 4 toxicities included fatigue (7.5%), anorexia (7.5%) and T-Bil elevation (7.5%). Significant antitumor activity combined with a mild toxicity profile was observed. This monotherapy warrants further evaluation in a randomized study.