Purpose: To determine the dose-limiting toxicities (DLTs) and the maximum tolerated doses (MTDs) of weekly high dose 5-fluorouracil (5FU) continuous infusion and leukovorin (LV) alternatively combined with oxaliplatin and irinotecan in patients with advanced tumors of the gastrointestinal (GI) tract.
Patients and methods: Patients received a fixed dose of LV (500 mg/m(2)) over 2 h infusion on weeks 1 to 4 and escalated doses of: oxaliplatin (starting dose 65 mg/m(2): 120 min i.v. infusion on weeks 1 and 3); irinotecan (starting dose 80 mg/m(2); 90 min i.v. infusion on weeks 2 and 4) and 5FU (starting dose 1500 mg/m(2); 22 h continuous i.v. infusion, on weeks 1 to 4), in cycles of 5 weeks. DLTs were evaluated during the fi rst cycle.
Results: Twenty-eight patients were treated on 8 dose levels and all but two patients received the regimen at least as second-line treatment. The DLT level was reached at the oxaliplatin dose of 90 mg/m(2), irinotecan dose of 110 mg/m(2), LV dose of 500 mg/m(2) and 5FU dose of 1750 mg/m(2); the recommended MTDs were 85 mg/m(2) for oxaliplatin, 110 mg/m(2) for irinotecan, 1750 mg/m(2) for 5FU and 500 mg/m(2) for LV. Grade 3 or 4 diarrhea and grade 3 nausea/vomiting were the dose-limiting events. Diarrhea was the most common toxicity of the regimen, occurring in 12 (42.8%) patients. Hematological toxicity was mild and there were no treatment- related deaths.
Conclusion: This weekly regimen showed a favorable toxicity profile and merits further investigation in patients with advanced/metastatic tumors of the GI tract.