Combination of interleukin-2 and gamma interferon in metastatic renal cell carcinoma

The use of high-dose interleukin-2 (IL2), alone or in association with lymphokine activated killer cells in patients with metastatic renal cell carcinoma (MRCC) results in a 20-25% response rate. However, the toxicity of IL2 is substantial and despite many clinical trials, response rates initially reported have not been improved. The aim of this study was to evaluate a combination of IL2 and gamma interferon (IFN) in MRCC with respect to both efficacy and tolerance. IL2 was given by continuous intravenous infusion at a daily dose of 24 × 10⁶ U/m² for 2 consecutive days during 5 consecutive weeks. Gamma IFN was given subcutaneously at a daily dose of 5 × 10⁶ U/m² on the same days as IL2. 33 patients with MRCC entered the study. Clinical responses were comparable with other published series: 7 patients (21%) achieved partial response, 13 (39%) were stable and 13 had progression, despite therapy. Immunological profile observed with this regimen showed a major increase in natural killer cells which became the predominant lymphocyte population at the end of the therapy. Tolerance was good with 92.5% of the planned doses actually received by the patients. This was reflected by an early discharge from the hospital in 95% of the cycles, increasing acceptability of the regimen by the patients.