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

Objective: To investigate whether the efficacy of interferon-beta (IFN beta) treatment of relapsing-remitting MS (RR-MS) was influenced by type, dose, and frequency of administration. Methods: 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 <= 5.5. The study was multicenter, controlled, open-label, randomized, head-to-head comparing IFN beta-1a 22 mu g once a week (n = 143) with IFN beta-1b 250 mu g every other day (n = 158), both subcutaneously, for 24 months. Patients who declined randomization were offered treatment with IFN beta-1b 250 mu g 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 Results: The annual relapse rates were virtually equal in the two arms of the randomized study (IFN beta-1a: 0.70; IFN beta-1b: 0.71); so were the time to first relapse and the time to sustained progression. In the nonrandomized patients (IFN beta-1b), the annual relapse rate was not significantly different, but the time to progression was shorter. Conclusion: In this study, 250 mu g interferon-beta-1b administered every other day did not prove clinically superior to once-a-week administration of 22 mu g interferon-beta-1a.