Only a few drugs are active in the treatment of well-differentiated endocrine carcinomas (WDEC). We evaluated the combination of the so-called 'de Gramont schedule' and irinotecan in these tumors in a phase II study. METHODS: 20 patients were enrolled in the study. The combination regimen included irinotecan, 180 mg/m(2) on day 1, followed by 200 mg/m(2) folinic acid in a 2-hour infusion, an intravenous 10-min bolus of 400 mg/m(2) 5-fluorouracil (5FU) and finally 600 mg/m(2) 5FU in a 22-hour infusion. Folinic acid and 5FU were repeated on day 2. Clinical, biological and morphological parameters were assessed by CT every 8 weeks. The site of the primary tumor was the pancreas in 10 cases, the lung in 3 cases and other sites in 7 cases. Sixteen patients had previously received chemotherapy, and 6 of them had had two lines of treatment. Six patients had previously been treated with chemoembolization. RESULTS: The median number of cycles administered was 8. Grade 3-4 neutropenia was observed in 8 patients, and 1 patient experienced febrile neutropenia. There was no toxicity-related death. No complete symptomatic response was observed in 7 evaluable patients; 4 patients had an objective biological response. One patient achieved a morphological objective response, stabilization was observed in 15, but progression occurred in 3 patients. Median survival was 15 months. CONCLUSION: The above-mentioned combination of LV5FU2 + irinotecan does not yield major activity in heavily pretreated unresectable metastatic gastroenteropancreatic WDEC, and significant toxicity was observed.