Prospective study of combined treatment with interferon-alpha and active vitamin D3 for Japanese patients with metastatic renal cell carcinoma.

Objectives: To assess the safety and efficacy of combined therapy with interferon-alpha (INF-alpha) and active vitamin D(3) for metastatic renal cell carcinoma (RCC).
Methods: Sixteen patients with metastatic RCC were enrolled in this prospective study. All received oral alfacalcidol (1 microg once daily) and INF-alpha (Sumiferon; 3 million units, three times a week). The primary endpoint was the response rate (defined as complete + partial remission). Secondary endpoints were cancer-specific survival and toxicity. The median follow-up period was 17 months (range: 5-49 months).
Results: The median age of the patients was 68 years (range: 41-73 years). The sites of metastases were: lung in 13 patients, bone in one, lung and bone in one, and lung, bone, and lymph nodes in one. Four patients (25%) had a partial response (PR), 10 patients (62.5%) showed no change (NC), and two patients (12.5%) had progressive disease (PD). The median cancer-specific survival time was 45 months. One patient had to discontinue vitamin D(3) because of hypercalcemia. Kaplan-Meier survival analysis revealed that metastasis at the time of initial diagnosis and older than average age were significant predictors of poor survival (P < 0.05).
Conclusions: Combined treatment with INF-alpha and active vitamin D(3) has shown to be safe and effective for metastatic RCC patients.