Phase II study of irinotecan and mitomycin C in 5-fluorouracil-pretreated patients with advanced colorectal and gastric cancer.

The aim of this phase II study was to investigate the tolerance and efficacy of a second-line irinotecan/mitomycin C combination in patients with advanced gastric or colorectal cancer, pretreated with 5-fluorouracil. Forty patients who had received 5-fluorouracil-based chemotherapy for advanced disease or adjuvant 5-fluorouracil treatment were enrolled. Chemotherapy consisted of irinotecan 125 mg/m2 and mitomycin C 5 mg/m2, given every 2 weeks. Treatment was continued until progression or limiting toxicity occurred. Five partial responses (12.5%), 22 cases of stable disease (55%) and 13 of progression (32.5%) were registered, giving an overall response rate of 12.5% [95% confidence interval (CI), 4.2-26.8%] and an overall control of tumor growth in 67.5% (95% CI, 50.8-81.4%) of patients. Median progression-free survival was 5 months, median survival time 8 months, and 1-year probability of survival was 21.6%. Diarrhea and neutropenia affected 25% and 12.5% of patients respectively, with only 7.5% experiencing grade 3-4 toxicity. There were no chemotherapy-related deaths or hospitalizations. This combination regimen was shown to be moderately effective with substantially lower toxicity than irinotecan monotherapy in 5-fluorouracil-pretreated patients with advanced gastric or colorectal cancer. It may represent an attractive option in patients at high risk for developing specific irinotecan toxicity.