A randomized, double-blind, dose-comparison study of weekly interferon beta-1a in relapsing MS.

BACKGROUND: Interferon beta-1a (IFNbeta-1a; Avonex) is effective for the treatment of relapsing MS; however, the optimal dose of IFNbeta-1a is not known. OBJECTIVE: To determine whether IFNbeta-1a 60 micro g IM once weekly is more effective than IFNbeta-1a 30 micro g IM once weekly in reducing disability progression in relapsing MS. METHODS: In a double-blind, parallel-group, dose-comparison study, 802 patients with relapsing MS from 38 centers in Europe were randomized to IFNbeta-1a 30 micro g (n = 402) or 60 micro g (n = 400) IM once weekly for >/=36 months. The primary endpoint was disability progression, defined as time to a sustained increase of >/=1.0 point on the Expanded Disability Status Scale (EDSS) persisting for 6 months. Additional endpoints included relapses, MRI, safety, immunogenicity, and subgroup analyses of disability progression. RESULTS: Both groups showed equal rates of disability progression (hazard ratio, 0.96; 95% CI, 0.77 to 1.20; p = 0.73). In both groups the proportion of subjects with progression of disability by 36 months estimated from Kaplan-Meier curves was 37%. No dose effects were observed on any of the secondary clinical endpoints. Only one MRI measure at one time point, number of new or enlarging T2 lesions at month 36 compared with month 24, showed a difference favoring the 60- micro g dose. Both doses were well tolerated; however, slightly higher incidences of flulike symptoms and muscle weakness were observed in the 60- micro g group. The incidences of neutralizing antibodies (titers >/= 20) were 2.3% in the 30- micro g group and 5.8% in the 60- micro g group. CONCLUSION: There was no difference between IFNbeta-1a 30 micro g and 60 micro g IM in clinical or MRI measures.

Benefit of interferon beta-1a on MSFC progression in secondary progressive MS.

BACKGROUND: Interferon beta-1a (IFNbeta-1a, Avonex) is efficacious in relapsing forms of MS. Studies of other IFNbeta preparations in secondary progressive MS (SPMS) yielded conflicting results. This study was undertaken to determine whether IFNbeta-1a slowed disease progression in SP-MS. METHODS: A total of 436 subjects with SPMS and Expanded Disability Status Scale (EDSS) score 3.5 to 6.5 were randomized to receive IFNbeta-1a (60 micro g) or placebo by weekly intramuscular injection for 2 years. The primary outcome measure, used for the first time in a large-scale MS trial, was baseline to month 24 change in the MS Functional Composite (MSFC), comprising quantitative tests of ambulation (Timed 25-Foot Walk), arm function (Nine-Hole Peg Test [9HPT]), and cognition (Paced Auditory Serial Addition Test [PASAT]). RESULTS: Median MSFC Z-score change was reduced 40.4% in IFNbeta-1a subjects (-0.096 vs -0.161 in placebo subjects, p = 0.033), an effect driven mainly by the 9HPT and PASAT. There was no discernible benefit on the EDSS, which in this range principally reflects walking ability. IFNbeta-1a subjects had 33% fewer relapses (p = 0.008). There was significant benefit on eight of 11 MS Quality of Life Inventory subscales. New or enlarging T2-hyperintense brain MRI lesions and gadolinium-enhancing lesions were reduced at months 12 and 24 (both p < 0.001). IFNbeta-1a was well tolerated by the majority of subjects. Neutralizing antibodies developed in 3.3% of IFNbeta-1a-treated subjects. CONCLUSIONS: IFNbeta-1a demonstrated benefit on MSFC progression, relapses, quality of life, and MRI activity in SPMS.