Continuous intravenous interleukin-2 infusion and subcutaneous interferon-alpha in metastatic renal cell carcinoma

In a phase II trial patients with metastatic renal cell carcinoma (MRCC) received two induction cycles each consisting of 24-h intravenous infusions of interleukin-2 (IL-2) 18 x 10(6) U/m2/day and interferon (IFN) 3 x 10(6) U/m2/day given subcutaneously on days 1-5 and 8-12 of a 2-week cycle. Between cycles 1 and 2 there was a 3-week treatment-free interval. Maintenance therapy consisted of four monthly cycles of IL-2 and IFN. Due to considerable toxicity the trial was prematurely closed after inclusion of 16 of 23 scheduled patients. Three partial responses were observed. Nine events of severe or life-threatening side-effects occurred and 8 patients were transferred to the intensive care unit. The combination of continuous intravenous high-dose infusions of IL-2 and subcutaneously given IFN is moderately effective, but too toxic for routine treatment of MRCC.