Objectives: The combination of irinotecan and raltitrexed is safe and active in 5-fluorouracil-refractory, metastatic colorectal cancer (CRC), with the advantage of its convenient three-weekly schedule. The aim of this multicenter phase II study was to assess its efficacy and toxicity in first-line treatment.
Methods: Between May 2000 and March 2001, 62 previously untreated patients received irinotecan (350 mg/m(2)) plus raltitrexed (3 mg/m(2)), with courses repeated every 21 days. Objective response was assessed every three courses, and treatment maintained until tumor progression or unacceptable toxicity.
Results: A total of 331 cycles were administered, with a median of five cycles per patient (range, 1-16). Seventeen patients achieved a partial response and 2 a complete response, for an overall intention-to-treat response rate of 30% (95% confidence interval, 18-44%). The incidence of grade 3-4 toxicity per patient was diarrhea (27%), emesis (13%), anemia (12%), neutropenia (9%), and asthenia (7%). Three patients (5%) died from treatment-related adverse events (diarrhea plus neutropenia). The median potential follow-up is now 37 months. Median survival was 12.2 months, and median time to progression was 6.3 months.
Conclusions: The combination of irinotecan plus raltitrexed is an easy comfortable schedule for patients with metastatic CRC, but both efficacy and toxicity results seem suboptimal for first-line treatment.