Renal cell carcinoma is relatively resistant to both chemotherapy and immunotherapy. Response, survival, duration of response, and toxicity of treatment were evaluated in patients with advanced renal cell carcinoma receiving a continuous intravenous infusion of 5-fluorouracil (5-FU) and low dose subcutaneous alfa-2b-interferon.

Between 1989 and 1994, 21 patients with advanced renal cell carcinoma underwent treatment with continuous intravenous infusion of 5-FU, 200 mg/m²/day, and subcutaneous injections of recombinant interferon alfa-2b (IFN-α), 1 x 10⁶ U/day.

Objective response was observed in 9 patients (43%). Complete response occurred in 4 patients (19%): 2 with lung, 1 with bone, and 1 with liver metastasis. Partial response occurred in 5 patients (24%). Three of 4 complete responders remain alive without recurrence. Mean survival rate was 195 weeks among complete responders, 184 weeks among partial responders, and 88 weeks among nonresponders. The overall mean duration of response was 101 weeks. Responders developed progression of disease a mean of 62 weeks after the initial response to therapy. Mild dose-dependent toxicity was related to 5-FU infusion. Nearly all toxicities subsided with the temporary cessation of 5-FU infusion and/or decreasing the dose of the infusion. Few if any of the toxicities appear to be directly related to the low dose interferon injections.

Although this study is based on a small sample size, we believe that the encouraging complete and partial responses, apparent prolongation of survival, and manageable toxicity of this combination therapy warrant further investigation with larger randomized trials.