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Randomized controlled trial of interferon-beta-1a in secondary progressive MS

Objective: To examine MRI changes resulting from treatment of secondary progressive MS (SPMS) with two doses of interferon-beta-1a (Rebif). Background: Interferon-beta (IFN-β) reduces relapses and delays progression in relapsing-remitting MS, but there are conflicting results on its clinical benefit in SPMS. Methods: In a double-blind, randomized, multicenter, placebo-controlled study (SPECTRIMS), 618 patients received IFN-β-1a 22 μg, 44 μg, or placebo subcutaneously three times weekly for 3 years. T2 activity and burden of disease (BOD) were measured in 617 patients by using semiannual proton density/T2-weighted (PD/T2) MRI scans. A cohort of 283 patients also had 11 monthly PD/T2 and T1-weighted gadolinium-enhanced (T1-Gd) scans at study start. Results: Treatment reduced median numbers of active lesions per patient per scan (semiannual T2 activity: 0.17, 0.20 and 0.67 for the high dose, low dose, and placebo, p < 0.0001; monthly combined unique activity [T1+T2]: 0.11, 0.22, and 1.00, p < 0.0001) and accumulation of BOD (percent change from baseline to month 36: −1.3, −0.5, and 10.0 for the high dose, low dose, and placebo, respectively; p = 0.0001). MRI benefit was most evident in the subgroup of patients who reported relapses in the 2 years before the study. Neutralizing antibody development was associated with reduction in treatment effect: antibody-positive patients did not show significant differences from placebo at either dose. Conclusions: Interferon-β-1a used in SPMS showed significant effects on all MRI measures, particularly in patients with relapses in the 2 years before the study.