Treatment of metastatic colorectal carcinoma with a combination of fluorouracil and recombinant interferon alfa-2b: preliminary data of a phase II study.

From March 1990 to January 1991 52 previously untreated patients with metastatic colorectal carcinoma were enrolled in a phase II study with the combination of interferon alfa-2b and fluorouracil (5-FU). 5-FU 750 mg/m2 per day was administered as continuous infusion for 5 days, then weekly in a dose of 750 mg/m2 as IV push injection starting on day 15. Interferon alfa-2b (Intron A, ESSEX Pharma) 9 x 10(6) units was given subcutaneously three times per week. Response to therapy was evaluated after 3 and 6 months. So far, data on response rates and toxicity are available in 32 patients: partial remission, 10 patients (31%); stable disease, nine patients (28%); progressive disease, 12 patients (37%); toxic deaths, two patients (6%). Projected median survival has not been reached after 11 months. In about one third of the patients severe side effects occurred with leukopenia grade 3 and 4, diarrhea, mucositis and septic complications being the clinically most important. We think that this combination is an effective but toxic regimen in advanced colorectal carcinoma. Further studies must reevaluate both the schedule and the doses of the drugs administered.