A randomized study of two interferon-beta treatments in relapsing-remitting multiple sclerosis.

Abstract

To investigate whether the efficacy of interferon-beta (IFNbeta) treatment of relapsing-remitting MS (RR-MS) was influenced by type, dose, and frequency of administration. From June 1996 through October 1997, the authors offered participation to all Danish RR-MS patients who met the following criteria: definite MS, at least two relapses within 2 years, age 18 to 55, and an Expanded Disability Status Scale (EDSS) score of < or = 5.5. The study was multicenter, controlled, open-label, randomized, head-to-head comparing IFNbeta-1a 22 microg once a week (n = 143) with IFNbeta-1b 250 microg every other day (n = 158), both subcutaneously, for 24 months. Patients who declined randomization were offered treatment with IFNbeta-1b 250 microg every other day (n = 120). The primary end-points were the annualized relapse rate, the time to first relapse, and neutralizing antibody formation. The secondary endpoint was time to sustained progression. The annual relapse rates were virtually equal in the two arms of the randomized study (IFNbeta-1a: 0.70; IFNbeta-1b: 0.71); so were the time to first relapse and the time to sustained progression. In the nonrandomized patients (IFNbeta-1b), the annual relapse rate was not significantly different, but the time to progression was shorter. In this study, 250 microg interferon-beta-1b administered every other day did not prove clinically superior to once-a-week administration of 22 microg interferon-beta-1a.