Randomised phase III study of gemcitabine, cisplatin plus S-1 (GCS) compared with gemcitabine plus cisplatin (GC) for unresectable or recurrent biliary tract cancer (KHBO1401-MITSUBA).

TPS4141 Background: Gemcitabine plus cisplatin (GC) therapy has been the standard palliative chemotherapy for patients with advanced biliary tract cancer (BTC). Our previous KHBO1002 trial, a single-arm phase II study of GC plus S-1 combination therapy (GCS), demonstrated a favorable survival benefit in BTC patients (Kanai M, et al. Cancer Chemother. Pharmacol. (2015) 75, 293-300). This phase III study aims to confirm the superiority of GCS to GC in terms of overall survival in patients with recurrent or unresectable BTC. Methods: Eligibility criteria include chemotherapy-naive patients with recurrent or unresectable biliary tract adenocarcinoma (gallbladder, intrahepatic biliary tract, extrahepatic biliary tract, or ampulla of Vater), an Eastern Cooperative Oncology Group performance status of 0–2, and adequate organ function. Eligible patients are randomized into either GCS arm or GC arm. In the GCS arm, gemcitabine and cisplatin were administered intravenously at doses of 1,000 or 25 mg/m (2), respecti...