Low activity of 13-cis-retinoic acid plus interferon alpha 2a in advanced renal cell carcinoma.

Retinoids and interferon alpha have shown synergistic activity against metastatic renal cell carcinoma in previous preclinical and clinical studies. Based on these results, we conducted a phase II trial of 13-cis-retinoic acid (cRA) at 1 mg/kg/dose interferon alpha2a (IFN) at initial dose of 9 MU three times a week. Thirty-one patients were entered, all evaluable for toxicity and 30 evaluable for response. One patient achieved a partial response and 10 patients achieved stable disease. Toxicity was mild and primarily related to interferon. No toxic deaths were reported. Median survival time was 10 months. At the dose and schedule used, cRA and interferon-alpha2a showed low activity against metastatic renal cell carcinoma. Further studies with this combination are not recommended.