THE OUTPATIENT USE OF RECOMBINANT HUMAN INTERLEUKIN-2 AND INTERFERON ALFA-2B IN ADVANCED MALIGNANCIES

We studied the safety, tolerance, and clinical effects of the combined administration of subcutaneous recombinant human interleukin-2 and interferon alfa-2b in 54 patients with advanced cancer, for whom no effective standard therapy was available. Treatment courses consisted of a 2-day interleukin-2 pulse (14.4-18 million units (MU) m2/day), followed by 3.6 up to 4.8 MU/m2/day, 5 days per week, over 6 consecutive weeks and interferon alfa-2b at 3 up to 6 MU/m2, administered two-three times weekly for 6 weeks. Overall, patients received more than 90% of the projected dose of interleukin-2 and interferon alfa-2b, respectively. Of 54 evaluable patients (32 renal cell cancer, 12 melanoma, eight colorectal cancer, one B-cell lymphoma, one Hodgkin's disease), four complete responses occurred in patients with renal cell carcinoma, and a greater than 50% reduction in tumour size (partial response) in six renal cell carcinoma patients and one melanoma patient. Moreover, 21 patients (13 renal carcinoma) had stable disease. The median duration of response was 19 months (range 16-22 months) in complete responders. Clinical responses were associated with a mean peripheral blood eosinophil count of more than 1,000/mu-L (P < 0.05 versus non-responders). Systemic toxicities included fever, chills, nausea, anorexia, and hypotension limited to WHO grades I and II in more than 80% of patients treated. No treatment-related deaths occurred. This combination of subcutaneously administered recombinant interleukin-2 and interferon alfa-2b has significantly diminished the side effects normally observed with high-dose intravenous recombinant interleukin-2, which requires admission to hospital. It has been shown to induce objective tumour regression in out-patients with progressive metastatic renal cell carcinoma and malignant melanoma.