Phase 2 study of modified irinotecan and bolus 5-fluorouracil/l-leucovorin in Japanese metastatic colorectal cancer patients

Introduction: Using the recommended doses obtained from our previous phase 1 trial of a modified Saltz chemotherapy regimen for metastatic colorectal cancer (weekly irinotecan and bolus 5-fluorouracil/l-leucovorin for 3 weeks every 28 days), we performed the present phase 2 trial to evaluate efficacy and toxicity. Methods: A total of 29 patients with metastatic colorectal cancer were included. Our modified Saltz regimen was administered. The primary endpoint was overall response rate. Results: Of the 29 patients, 11 had previous chemotherapy. A partial response occurred in 11 patients, stable disease in 16 patients, and progressive disease in two patients. Disease control rate was 93.1%. Response rates with and without previous treatment were 18.2% and 50%, respectively. Median progression-free survival was 17.3 months. The main hematologic toxicities were leukopenia (22.6%) and neutropenia (45.2%). No treatment-related deaths occurred. Conclusion: Our modified Saltz regimen exhibited sufficient efficacy, feasibility, and manageable toxicity as a therapeutic option for selected colorectal cancer patients.