Recombinant interferon alfa-2a with or without vinblastine in metastatic renal cell carcinoma.

Twenty patients with measurable metastatic renal cell carcinoma (RCC) were were treated with interferon alfa-2a (Roferon-A), 36 X 10(6)U intramuscularly 3 times weekly, alone (2 patients) or in combination with vinblastine, 0.10-0.15 mg/kg intravenously every 2 to 3 weeks. Objective responses in the lung, bone, liver, and lymph node metastases were seen in 6 of 18 evaluable patients. Dose reduction of interferon alfa-2a was necessary in 19 of the 20 patients due to intolerable flu-like side effects and fatigue. Bone marrow suppression and increase of gamma-GT represented the most often observed objective toxicity. The preliminary results of this combination treatment in RCC are promising and warrant randomized studies exploring the role of vinblastine. The dose of interferon alfa-2a should be reduced by 50% to avoid excessive toxicity and to maximize patient compliance.