Oxaliplatin plus irinotecan and FU-FOL combination and pharmacokinetic analysis in advanced colorectal cancer patients.

This phase I-II trial was designed to assess the effect of irinotecan on oxaliplatin pharmacokinetics and to determine the MDT of both drugs when administered in combination. Treatment was repeated every 2 weeks. Pharmacokinetic studies were performed on cycle 1 and 2 to assess the best sequence and detect any interaction between the two drugs. Thirty-four patients with advanced colorectal cancer were enrolled; 28 of them (82%) had liver involvement. The main toxicities were neutropenia and delayed diarrhea; 5 patients (14%) experienced febrile neutropenia. Dose-limiting toxicity was experienced at levels 1/2/3/4/5 by 4/10, 1/6, 3/6, 3/8, and 3/4 patients, respectively. Fifteen patients responded (2 CR; 13 PR) for an ORR of 44%. No pharmacokinetic interactions between irinotecan and oxaliplatin were detected. The recommended dose for future phase II trials is oxaliplatin 85 mg/m and irinotecan 180 mg/m2 on day 1 combined with 5FU/leucovorin according to the de Gramont regimen at days 2 and 3. Twenty-nine percent of patients underwent secondary hepatectomy with curative intent, and two of them are long-term disease-free survivors. It would appear that the dose and schedule defined by this trial could be proposed as front-line therapy for advanced colorectal carcinoma to establish rapid disease control and to permit patients to proceed to surgery.