Cohorts of 3 patients receive interleukin-12 IV push on day 1, followed by escalating doses of interferon alfa by subcutaneous injection at 24, 48, 72, 96 and 120 hours. Courses repeat every 2 weeks for 6 months (12 courses total) in the absence of unacceptable toxicity and disease progression. Patients achieving partial response or stable disease at the completion of 6 months of therapy may receive additional courses of therapy for up to 24 months. Dose escalation of interferon alfa continues in subsequent cohorts in the absence of dose limiting toxicity (DLT). If 1 of 3 patients experiences DLT at a dose level, then 3 additional patients are entered at that dose level. If 2 of 6 patients experience DLT, then dose escalation stops. The maximum tolerated dose is defined as 1 level below that dose at which 2 or more of 6 patients experience DLT. Patients are followed every 3 months for 1 year and then every 6 months thereafter.