Chronically administered immunotherapy with low-dose IL-2 and IFN-alpha in metastatic renal cell carcinoma: a feasible option for patients with a good prognostic profile

Objective: We report the results obtained using an original immunotherapy schedule featuring chronically administered low-dose interleukin-2 (IL-2) and interferon-alpha (IFN-alpha) in patients with metastatic renal cell carcinoma (mRCC), and we assess treatment efficacy according to the patients' prognostic profiles. Methods: 138 consecutive patients were enrolled, and received IL-2 (1 million IU/m(2)) subcutaneously twice daily on days 1 and 2, and once daily on days 3-5 of each week, and IFN-alpha (1.8 million IU/m(2)) intramuscularly once daily on days 3 and 5. Each cycle consisted of 4 consecutive weeks and was repeated indefinitely at 4-month intervals regardless of response. The patients' baseline risk profile was assessed using Negrier's stratification system. Results: The overall response rate was 10.9% (95% CI 6.7-17.2), and median overall survival was 19.6 months (95% CI 14.2 - 28.2). Treatment-related toxicity was mostly WHO grade 2 or below. Survival in the low-, intermediate- and high-risk groups was significantly different (p for trend < 0.001), with low-risk patients having a median survival of 65.1 months ( 95% CI 42.7-84.2). Conclusion: Chronically administered low-dose IL-2 and IFN-alpha may be a safe and effective option for low-risk mRCC patients.