Recombinant beta-interferon in the treatment of patients with metastatic renal cell carcinoma

We report on the clinical course of 15 patients with metastatic renal cell carcinoma (RCC) who were treated with recombinant beta-interferon as part of a phase I-II study. There were no objective responders among the 15 patients treated with recombinant beta-interferon at an i.v. dose escalating from 90 x 10⁶ to 720 x 10⁶ U given three times a week until there was documented disease progression or complete response (CR). Overall median survival was 24 months. One patient refused further treatment after 7 weeks. The major side effects of treatment included cardiovascular events (20%), mental status change requiring cessation of drug (6.7%), and grade 3 headaches/myalgias (26.7%). There were no life-threatening side effects observed; however, cardiac events led to the termination of treatment in three patients. Other minor toxicities included fatigue (46.7%), proteinuria (60%), diarrhea (6.7%), nausea and vomiting (13.3%), persistent fever (6.7%), and transient visual disturbance (6.7%). Thus, at our institution, in a cohort of 15 patients with metastatic RCC, recombinant beta-interferon when given i.v. at a dose ≤720 x 10⁶ U three times per week, yielded no clinical antitumor activity. A review of the literature on the use of beta-interferon for metastatic RCC suggests that there may be some efficacy, but our experience with escalating i.v. doses ≤720 x 10⁶ U given three times a week does not support it. Moreover, at these doses, one may find serious cardiovascular events although further studies need to be done in order to clearly define dose-related side effects as well as optimal efficacy-to-toxicity ratio.