Materials and Methods: In a phase II study of patients with metastatic renal cell carcinoma the efficacy and toxicity of a treatment regimen were evaluated using interleukin-2 and interferon-alpha 2 subcutaneously in combination with intravenous 5-flourouracil. The treatment protocol consisted of an 8-week cycle given on an outpatient basis, with 6 to 9 MU/m.(2) interferon-alpha given 1 to 3 times a week during the 8 weeks, and sequentially combined with 5 to 20 MU/m.(2) interleukin-2,3 times a week for 4 weeks and 750 mg./m.(2) 5-fluorouracil once a week for 4 weeks.

Results: Among 25 consecutive men and 9 women treated 3 (9%) had a complete and 10 (29%) had a partial remission (overall objective response rate 38%). Median response duration (complete plus partial) was 12.5 months (range 3 to 20+). Stable disease lasting 3 to 24+ months was noted in 12 patients (35%). There were only minor side effects, for a maximum toxicity grade of I in 3 patients, II in 25 and III in 6 according to the World Health Organization classification. There were no dose limiting toxicities and no treatment related deaths.

Conclusions: Triple drug immunochemotherapy resulted in a significant clinical effect comparable to an aggressive intravenous interleukin-2 treatment regimen but without significant toxicity.