Overview of European pilot study of interferon beta-Ib in primary progressive multiple sclerosis. Intramuscular interferon beta-1a for disease progression in relapsing multiple sclerosis. The Multiple Sclerosis Collaborative Research Group (MSCRG)
This short monograph describes a trial of interferon beta-1b in patients with primary progressive multiple sclerosis (PPMS) or transitional MS. Designed as a randomized, placebo-controlled pilot, the trial randomly placed 73 eligible patients into two groups, placebo or interferon beta-1b 8 MIU given subcutaneously every other day for two years. Significant differences favouring interferon beta-1b in the MSFC score, T2 lesion volume and TI lesion volume at 24 months were observed. Further study of interferon beta-Ib therapy in PPMS patients in warranted. The accepted standard treatment of relapsing multiple sclerosis consists of medications for disease symptoms, including treatment for acute exacerbations. However, currently there is no therapy that alters the progression of physical disability associated with this disease. The purpose of this study was to determine whether interferon beta-1a could slow the progressive, irreversible, neurological disability of relapsing multiple sclerosis. Three hundred one patients with relapsing multiple sclerosis were randomized into a double-blinded, placebo-controlled, multicenter phase III trial of interferon beta-1a. Interferon beta-1a, 6.0 million units (30 micrograms¿, was administered by intramuscular injection weekly. The primary outcome variable was time to sustained disability progression of at least 1.0 point on the Kurtzke Expanded Disability Status Scale (EDSS). Interferon beta-1a treatment produced a significant delay in time to sustained EDSS progression (p = 0.02). The Kaplan-Meier estimate of the proportion of patients progressing by the end of 104 weeks was 34.9% in the placebo group and 21.9% in the interferon beta-1a-treated group. Patients treated with interferon beta-1a also had significantly fewer exacerbations (p = 0.03) and a significantly lower number and volume of gadolinium-enhanced brain lesions on magnetic resonance images (p-values ranging between 0.02 and 0.05). Over 2 years, the annual exacerbation rate was 0.90 in placebo-treated patients versus 0.61 in interferon beta-1a-treated patients. There were no major adverse events related to treatment. Interferon beta-1a had a significant beneficial impact in relapsing multiple sclerosis patients by reducing the accumulation of permanent physical disability, exacerbation frequency, and disease activity measured by gadolinium-enhanced lesions on brain magnetic resonance images. This treatment may alter the fundamental course of relapsing multiple sclerosis.
Limited data on the effect of ß-interferon treatment on PPMS exists. Only two single-centre placebo controlled trials of interferon beta have been done. Based on this review, the included studies showed that ß-interferon treatment was not associated with reduced disability progression in PPMS patients. However, the trial population was too small to allow definitive conclusions on the efficacy of ß-interferon therapy in PPMS patients. Larger research studies need to be done in patients with PPMS in order to clarify whether ß-interferon is effective in this population.