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.