Phase II study of interferon alpha in metastatic renal-cell carcinoma: a progress report.

Partially purified interferon alpha (IFN alpha) was administered to 50 patients with metastatic renal-cell carcinoma (RCC) studied for more than two years. Complete or partial remissions were observed in 26% of the patients. Duration of remissions range from two to 16 months (median, six months). No distinct prognostic factors were clearly identified in the responsive patients, but responses occurred more frequently in men with optimal performance status who had undergone nephrectomy and in whom the metastatic disease was confined to the lungs, pleura, or mediastinum. Leukopenia and granulocytopenia were useful markers of biological activity but did not predict tumor response. Side effects and toxicity at the dosage used (3 X 10(6) units intramuscularly daily) were well-tolerated and consisted predominantly of fatigue and asthenia. We concluded that IFN alpha is useful for palliating metastatic RCC, but no impact on survival was demonstrated. Further studies are required to determine the optimal dose, routes of administration, and treatment schedules.