A randomized study of low-dose interleukin-2 subcutaneous immunotherapy versus interleukin-2 plus interferon-alpha as first line therapy for metastatic renal cell carcinoma

Abstract

Aims and background: IL-2 given subcutaneously in combination with interferon-alpha 2b (IFN) appears to induce a response rate comparable to that obtained with IL-2 intravenous injection in patients with metastatic renal cell carcinoma (RCC) but with lower toxicity. The role of IFN when combined with IL-2 has however still to be defined. The present study was performed to draw some preliminary conclusions about the effect of IFN in combination with IL-2 in metastatic RCC.

Methods: The study included 30 consecutive patients with metastatic RCC who were randomized to treatment with IL-2 subcutaneous therapy (3 million IU twice/daily for 5 days/week for 6 weeks) or with IL-2 plus IFN (5 million U/m2 subcutaneously thrice weekly). In patients without progressive disease, a second cycle was repeated after a 28-day rest period.

Results: No significant difference in partial response rate was found between patients treated with IL-2 alone and those given IL-2 plus IFN (5/15 vs 4/15). Similarly, no difference was seen in the percentage of stable disease (7/15 vs 7/15). Toxicity was higher in patients who received IL-2 plus IFN. Lymphocyte and eosinophil mean increase was higher in patients treated with IL-2 alone than in those treated with IL-2 plus IFN, without however any significant difference.

Conclusions: The present results, which require confirmation in a larger series, indicate that combination with IFN does not increase the efficacy of IL-2 subcutaneous immunotherapy in metastatic RCC but only the toxicity of treatment.