Magnetic Resonance Imaging Effects of Interferon Beta-1b in the BENEFIT Study: Integrated 2-Year Results

Background In the Betaseron/Betaferon in Newly Emerging Multiple Sclerosis for Initial Treatment (BENEFIT) study, interferon beta-1b delayed conversion to multiple sclerosis in patients with a first clinical event and at least 2 clinically silent brain magnetic resonance imaging (MRI) lesions. Objective To examine detailed MRI findings from the first 2 years of this trial. Design Double-blind, placebo-controlled, randomized, parallel-group, multicenter, phase 3 study. Setting Ninety-eight centers worldwide. Patients A total of 404 individuals with a first demyelinating event suggestive of multiple sclerosis. Interventions Patients were randomized to receive interferon beta-1b, 250 μg subcutaneously every other day, or placebo. After 24 months of treatment or on conversion to clinically definite multiple sclerosis, open-label interferon beta-1b treatment was offered. Main Outcome Measures Reported MRI data from patients completing 2 years of follow-up. Results Data were analyzed from 248 patients taking interferon beta-1b and 156 taking placebo. Across 2 years the cumulative number of newly active lesions was lower in patients receiving interferon beta-1b vs placebo (median, 2.0 vs 5.0 [reduction of 60%]; P P P P  = .02). Conclusions Interferon beta-1b treatment had a robust effect on MRI measures, supporting its value as an early intervention in this patient group. This effect was maintained despite including patients who switched from placebo to interferon beta-1b in the active treatment group. Trial Registration clinicaltrials.gov Identifier:NCT00185211