Interleukin-2, interferon-α and medroxyprogesterone acetate in metastatic renal cell carcinoma

Background: Interleukin-2 (IL-2) and interferon-α (IFN-α) are the main immuno-biological agents used in the therapy of metastatic renal cell carcinoma (RCC). Unfortunately the promising results obtained in biological studies have not yet been confirmed in clinical studies. One reason is linked to the immunosuppression of metastatic patients which is caused by macrophage products. IL-6 in particular is considered a growth factor for RCC. Medroxyprogesterone acetate (MPA) may interfere with IL-6 macrophage production, possibly causing a synergistic effect in association with IL-2 and IFN-α. Therefore the purpose of our study was to evaluate the toxicity and the efficacy of the association between IL-2, IFN-α and MPA. Patients and Methods: Forty-two consecutive patients with metastatic RCC were enrolled. IL-2 was administered subcutaneously at doses of 4.5 million UI on days 1-5, 8-12, 15-19 and 22-26; IFN-α was administered s.c. at a dose of 3 million t.t.w; MPA was administered orally at a dose of 1000 mg daily. This schedule was repeated after a rest of 2 weeks. Results: Toxicity was mild: the main symptoms observed were fatigue and fever. Six CR (14%), five PR (12%), thirteen SD (31%) and seventeen PD (41%) were observed for an overall response rate of 26%. Patients with good PS and low levels of CRP had a better prognosis. Conclusion: Considering both the good activity and the low toxicity of this scheme, we think that it could be carried out in normal clinical practice.