BACKGROUND: It is unclear whether recombinant β interferons (IFNβ) can be effective in secondary progressive MS (SPMS). The aim was to determine whether IFNβ can reduce the risk of disability and cognitive impairment progression in SPMS.
METHODS: Using Cochrane methodology, we reviewed all randomised placebo controlled trials of IFNβ in SPMSers (1995-March 2012).
RESULTS: 5 trials (3082 MSers) were included. After 3 years, interferons did not reduce disability progression, confirmed at 6 months (RR 0.98, 95% CI 0.82 to 1.16). A small reduction in the number of MSers who had relapses during the first 3 years of treatment (RR 0.91, 0.84 to 0.97) was found. No analysis of cognitive data was possible. More treated than placebo MSers dropped out for adverse events.
CONCLUSION: 3 year treatment with IFNβ does not delay permanent disability in SPMS but reduces relapse risk, indicating that the anti-inflammatory effect of IFNβ is unable to prevent MS progression once it has become established.