Background: The aim of this study was to determine the maximum-tolerated dose (MTD) and the recommended dose of irinotecan and oxaliplatin with a fixed 5-fluorouracil (5-FU)/leucovorin (LV) regimen in patients with metastatic solid tumors.
Patients and methods: The trial was designed to evaluate escalating doses of oxaliplatin and irinotecan, starting at 60 mg/m2 and 90 mg/m2, respectively, given at day 1 with the full-dose LV5FU2 regimen, given on days 1 and 2 as follows: folinic acid 200 mg/m2 followed by 5-FU 400 mg/m2 bolus and 600 mg/m2 22 h continuous infusion, every 2 weeks. The second cohort of patients was treated at the recommended dose for oxaliplatin and irinotecan with the simplified LV5FU regimen: on day 1, a 2-h infusion of folinic acid (400 mg/m2), followed by a 10-min intravenous bolus of 5-FU (400 mg/m2), followed by a continuous infusion of 5-FU (2400 mg/m2) over 46 h.
Results: Thirty-four patients were treated at the following dose levels (oxaliplatin/irinotecan mg/m2): 60/90, 60/120, 85/120, 85/150, 85/180, 85/200 and 85/220 and seven patients were treated at the recommended dose with the simplified LV5FU scheme. The MTD was reached at dose level 85/220 mg/m2 but the recommended dose chosen for the second step was 85/180 mg/m2 to keep a better compliance with the biweekly schedule. Main grade 3/4 toxicities per patient included the following: neutropenia in 78% (febrile episodes in 12%), diarrhea in 27%, nausea/vomiting in 24% and peripheral neuropathy in 37% (Lévi's scale). Antitumor activity was observed at almost all dose levels. Most objective responses were observed in digestive malignancies, since 10 out of 11 were obtained in five colorectal cancers, two pancreatic cancers, two cholangiocarcinoma and one gastric cancer.
Conclusion: The recommended dose for the triple association is 85/180 mg/m2 of oxaliplatin and irinotecan, respectively, with LV5FU2 or simplified LV5FU. The antitumor activity in gastrointestinal malignancies should be evaluated in phase II studies in different tumor types.