European experience with irinotecan plus fluorouracil/folinic acid or mitomycin

Tremendous progress has been made in the medical treatment of advanced colorectal cancer during the past 2 to 3 years, due to the availability of several new drugs. Of these new agents, irinotecan (CPT-11 [Camptosar]) seems to be one of the most active against advanced colorectal cancer. It is, therefore, a good candidate for combination with the more classic cytotoxic agents for this disease. This article summarizes several European phase I and II studies in which irinotecan has been combined with (1) fluorouracil (5-FU) alone, given as a repeated bolus injection or a protracted infusion; (2) 5-FU modulated by folinic acid (leucovorin) according to different schedules; or (3) mitomycin (Mutamycin). All of these studies have demonstrated clinical responses in patients with advanced colorectal carcinoma, including complete responses. The toxicity profiles of the various combinations seem to be acceptable; neutropenia and delayed diarrhea are the most frequent side effects. Large phase III studies are still warranted to demonstrate the benefit of these irinotecan-based regimens.