Phase II study of recombinant alpha-interferon (rIFN alpha) and continuous-infusion 5-fluorouracil in metastatic breast cancer.

Twenty-six patients with metastatic breast cancer were offered a phase II combination of recombinant α-interferon and continuous-infusion 5-fluorouracil (5-FU). 5-FU was administered at 750 mg/m2 daily for 5 days as a continuous infusion and recombinant interferon at 5 million U/m2 subcutaneously days 1, 3, and 5 of each course. The courses were repeated every 14 days. Despite moderate nonmyelosuppressive toxicity, only two (8%) partial remissions were observed. In this schedule, the addition of recombinant α-interferon to conventional continuous-infusion 5-FU resulted in a response rate of 8%.