Interferon beta in relapsing-remitting multiple sclerosis: an independent postmarketing study in southern Italy.

This independent, population-based surveillance study monitored the efficacy and safety of interferon beta (IFNbeta) products in 1033 patients with relapsing-remitting multiple sclerosis (RRMS) from 15 centres in Italy. Relapses, Expanded Disability Status Scale (EDSS) scores, and adverse events were evaluated for up to 24 months. Data of patients with a baseline EDSS score < or = 3.5 are reported. The proportions of relapse-free patients were similar among the groups at 12 and 24 months (P = 0.10). IFNbeta products produced significant reductions from baseline in relapse rates at 12 and 24 months (P < 0.001), with no differences among treatments (P = 0.2). There were no significant differences in mean EDSS change among groups at 12 or 24 months. The IFNbeta-1b group showed a higher incidence of adverse events during the first year of treatment (P < 0.05) than IFNbeta-1a groups, and more withdrawals (10%) compared with Avonex (5%) at 24 months. IFNbeta products are equally effective in low disability RRMS, but IFNbeta-1a may have a more favorable efficacy/tolerability ratio.