Patients receive interleukin-12 (IL-12) IV on days 1 and 4 for 6 weeks. Beginning on day 4 of the third week, patients receive interleukin-2 (IL-2) subcutaneously 1 hour before and 20 hours after each dose of IL-12. On subsequent courses, IL-2 and IL-12 are administered on days 1 and 4 of each week. Treatment continues for 6 weeks in the absence of disease progression or unacceptable toxicity. Patients with disease response may continue treatment until complete response or disease progression.