A prospective,open-label treatment trial to compare the effect of IFNβ-1a (Avonex®),IFNβ-1b (Betaseron®),and glatiramer acetate (Copaxone®) on the relapse rate in relapsing-remitting multiple sclerosis: results after 18 months of therapy

Abstract

We previously reported results of a 12 month prospective, non-randomized, open-label treatment trial of immunomodulatory therapy in patients with relapsing-remitting multiple sclerosis (RRMS). We now report the results after 18 months of follow-up. Our primary objective was to compare the effect of INFβ-1a (Avonex®), IFNβ-1b (Betaseron®), and Glatiramer Acetate (GA, Copaxone®) to no treatment on the relapse rate in patients with RRMS. One hundred and fifty-six consecutive patients with clinically definite RRMS with a Kurtzke scale (EDSS) score of 4 or less were followed for 18 months. Prior 2-year relapse history and available chart information was carefully reviewed at the time of enrollment. Thirty-three of 156 elected no treatment at enrollment; 40 elected IFNβ-1a, 41 IFNβ-1b, and 42 chose GA. There were no statistically significant differences among the four groups at enrollment. After 18 months of treatment, 122 patients remained in their original treatment group. Compared to the untreated group (1.02), mean annualized number of relapses was significantly reduced only in the GA (0.49, P40.0001) and IFNβ-1b groups (0.55, P=0.001) in contrast to the IFNβ-1a treated patients (0.81, P=0.106) who did not show a significant reduction. Despite limitations of the study design, the results provide helpful clinical information regarding the relative efficacy of each therapy in mildly affected treatment naïve RRMS patients.