Randomized phase II/III trial of interferon alfa-2a with and without 13-cis-retinoic acid in patients with progressive metastatic renal cell carcinoma: The European Organisation for Research and Treatment of Cancer Genito-Urinary Tract Cancer Group (EORTC 30951) Aass N, De Mulder PHM, Mickisch GHJ, Mulders P, van Oosterom AT, van Poppel H, Fossa SD, de Prijck L, Sylvester RJ, Department of Clinical Cancer Research, The Norwegian Radium Hospital, Oslo, Norway.
PURPOSE: A randomized phase II/III trial was conducted to determine whether combination treatment with 13-cis-retinoic acid (13-CRA) plus interferon alfa-2a (IFN-alpha-2a) was superior to IFN-alpha-2a alone in patients with progressive metastatic renal cell carcinoma. PATIENTS AND METHODS: Three hundred twenty patients were randomly assigned to treatment with IFN-alpha-2a plus 13-CRA or to IFN-alpha-2a alone. IFN-alpha-2a was given daily subcutaneously, starting at a dose of 3 million units (MU). The dose was escalated every 7 days from 3 to 9 MU by increments of 3 MU. Patients randomly assigned to combination therapy received oral 13-CRA 1 mg/kg/d plus IFN-alpha-2a. RESULTS: Median time to progression was 5.1 months for patients treated with the combination and 3.4 months for patients on IFN-alpha-2a alone (P = .008). Progression-free survival rates at 6 months were 43% for patients receiving combined therapy and 30% for patients on IFN-alpha-2a, and at 12 months, 27% and 17%, respectively. Median overall survival was 17.3 months for patients on IFN-alpha-2a and 13-CRA, and 13.2 months for patients treated with IFN-alpha-2a (P = .048). Twenty-two percent of the patients receiving the combination stopped treatment due to toxicity, as compared with 16% on IFN-alpha-2a. CONCLUSION: Progression-free and overall survival for patients with progressive metastatic renal cell carcinoma treated with IFN-alpha-2a plus 13-CRA were significantly longer compared with patients on IFN-alpha-2a alone (P = .007 and P = .048, respectively). Improvement in efficacy in the combination arm was accompanied by increased, though not serious, toxicity.