Résumé : Background: Based on a recent pharmacokinetic study suggesting that high biliary levels of mitomycin C (MMC) may be achieved as a result of an entero-hepatic recycling mechanism, we conducted a Phase II EORTC trial which involved MMC administration to patients with non-resectable biliary tract carcinoma. Patients and methods: Of the 34 patients entered in the study, 30 were eligible (llm + 19f, median age 58 yrs). I.V. bolus injections of 15 mg/m2 MMC were administered at sixweek intervals. The tumors were confined to the liver in 17 patients and 13 had extra-hepatic localizations. Results: All 30 eligible patients were evaluable for toxicity and response. Mild thrombocytopenia was the main toxic side effect. Severe, WHO grade III/IV thrombocytopenia was limited to 4 patients. The haemolytic uraemic syndrome was not observed and there were no toxic deaths. Of 30 patients, 3 had partial remissions (overall response 10%, 95% confidence interval 2%-27%). Conclusions: This study, the largest such ongoing phase II trial, shows no significant activity of single-agent MMC in patients with advanced biliary tract carcinoma. © 1993 Kluwer Academic Publishers.