Phase II evaluation of recombinant alpha-2a-interferon and continuous infusion fluorouracil in previously untreated metastatic colorectal adenocarcinoma.

BACKGROUND: Thirty-nine patients with advanced measurable metastatic colorectal carcinoma were entered in a clinical trial of recombinant alpha-2a-interferon (r alpha-2a-IFN) and continuous-infusion 5-fluorouracil (5-FU). Patients had not been treated previously with chemotherapy and had bidimensionally measurable disease.

METHODS: A course of therapy consisted of a 5-day continuous infusion of 5-FU, 750 mg/m2/day, with r alpha-2a-IFN, 9 x 10(6) IU, subcutaneously, on days 1, 3 and 5 of the 5-FU infusion. A course of therapy was repeated every 15 days, and patients were examined for response after receiving four courses of therapy.

RESULTS: One patient had a complete response, and 11 patients experienced partial responses, for an overall response rate of 31% (95% confidence interval [CI], 17-48%). The median duration of response was 7.5 months (range, 2-13 months). Fifty-two percent of the patients entered in this trial are alive at time of this writing, with a median follow-up duration of 12.2 months (range, 6-24 months). Grade 3-4 toxicities included mucositis (nine patients), diarrhea (two patients), granulocytopenia (two patients), and fatigue (three patients).

CONCLUSION: This regimen of 5-FU with r alpha-2a-IFN administration does not appear to be superior to previously published schedules of 5-FU with r alpha-2a-IFN or to other methods that modulate 5-FU.