Purpose: We aimed to determine the maximum-tolerated dose (MTD) and dose-limiting toxicities (DLTs) of the addition of S-1, an oral fluorouracil derivative, to gemcitabine and cisplatin combination therapy, which is the current standard treatment for advanced biliary tract cancer.
Methods: Patients with histologically or cytologically confirmed unresectable or recurrent biliary tract cancer were eligible for inclusion. The planned dosages of gemcitabine (mg/m(2))/cisplatin (mg/m(2))/S-1 (mg/m(2)/day) were as follows: level 0, 800/25/60; level 1, 1,000/25/60; and levels 2 and 3, 1,000/25/80. In each cycle, gemcitabine and cisplatin were intravenously administered on day 1 (or days 1 and 8 at level 3), and S-1 was orally administered twice daily on days 1-7 (or days 1-14 at level 3); this was repeated every 14 days (or 21 days at level 3).
Results: Seventeen patients were enrolled, and level 1 was chosen as the starting dose. Two of six patients developed DLTs (grade 4 neutropenia and grade 3 febrile neutropenia) at level 1, and the dose was escalated to level 2. DLTs (grade 3 rashes and grade 3 vasovagal reactions) occurred in two of six assessable patients at level 2; we then proceeded to level 3. The first three assessable patients enrolled at level 3 developed DLTs (two cases of grade 4 neutropenia, one of grade 4 leucopenia, two of grade 3 fatigue, one of grade 3 anorexia, and one of grade 3 febrile neutropenia) during their first cycle, and this dose was determined to be the MTD. Therefore, we selected level 2 as the recommended dose (RD) for a subsequent phase II study.
Conclusions: We determined the RD of gemcitabine/cisplatin/S-1 combination therapy for advanced biliary tract cancer; we are proceeding to a phase II study to investigate the efficacy of this combination therapy for advanced biliary tract cancer.