Background: Within the past 10 years, several immunomodulatory agents (IMAs) have become available for the treatment of relapsing multiple sclerosis (MS), making therapeutic decisions more complex. We performed a systematic review of the literature to assess the efficacy and safety of these agents on physical, inflammatory, and cognitive measures of disease activity.
Methods: We identified relevant studies by searching electronic databases (MEDLINE and Current Contents) from January 1, 1993, through August 31, 2001. We included English-language reports of data from phase 3 trials of interferon beta-1b (Betaseron), 2 preparations of interferon beta-1a (Avonex and Rebif), or glatiramer acetate (Copaxone) for the treatment of relapsing MS.
Results: Twenty-one studies met explicit inclusion criteria. Comparison of study results indicated no differences among IMAs regarding their efficacy on relapse-related measures. Interferon beta-1a significantly reduced disability progression, whereas no significant effect of glatiramer acetate or interferon beta-1b on disability progression was seen. On inflammatory measures, all of the IMAs showed reductions in the burden of disease (T2-weighted lesions) to varying degrees. Interferon beta and glatiramer acetate reduced new lesion activity; however, interferon beta had a more profound effect. One interferon beta-1a preparation (Avonex) appeared to reduce brain atrophy, whereas glatiramer acetate showed an effect in 1 of 2 studies. Only Avonex demonstrated efficacy in slowing progression of cognitive dysfunction.
Conclusions: Data show that the IMAs have similar effects on several physical and inflammatory measures. In addition, Avonex has demonstrated efficacy in slowing cognitive progression in relapsing MS. One disadvantage of interferon beta is the possibility of immunogenicity, which may occur more often with subcutaneous administration. The IMAs have similar safety and tolerability profiles.