alpha-Interferon and interleukin-2 in renal cell carcinoma: studies in nonhospitalized patients.

We have studied the safety, tolerance, and clinical effects of the combined administration of subcutaneous recombinant human interleukin-2 and alpha-interferon in 34 patients with metastatic renal cell carcinoma who had undergone tumor nephrectomy. Treatment courses consisted of a 2-day interleukin-2 pulse (14.4 to 18.0 million IU/m2/d), followed by 3.6 to 4.8 million IU/m2/d, 5 days per week, over 6 consecutive weeks, and alpha-interferon at 3.0 to 6.0 million U/m2, administered 2 to 3 times weekly for 6 weeks. Patients received more than 90% of the projected dose of interleukin-2 and alpha-interferon, respectively. Of 34 patients with metastatic progressive renal cell carcinoma in this study, four had complete response and six had greater than 50% reduction in tumor size (ie, partial response). There were, in addition, 13 patients with stable disease. So far, all complete responses have been durable, with a median duration of 23+ months. Clinical responses were associated with a mean peripheral blood eosinophil count of more than 1,000/microliters (P less than .05). The predominant toxicities included fever, chills, nausea, anorexia, and hypotension, and were limited to World Health Organization grades 1 and 2 in more than 80% of patients treated. No treatment-related deaths occurred. This combination of subcutaneously administered recombinant interleukin-2 and alpha-interferon has significantly reduced the side effects normally observed with high-dose intravenous recombinant interleukin-2. It can induce objective tumor regressions in patients with progressive metastatic renal cell carcinoma. Unlike the intravenous schedules developed by Rosenberg and West, which require admission to hospital, all the patients in this study were treated in an outpatient setting.