Merck KGaA Rebif trial meets endpoint

Germany's Merck KGaA and its Merck Serono division presented data from the ongoing IMPROVE study on the new formulation of Rebif (interferon beta-1a) in patients with relapsing-remitting multiple sclerosis, showing the trial had met its primary endpoint, at a late-breaking session of the World Congress on Treatment and Research in Multiple Sclerosis in Montreal, Canada.

The IMPROVE study is a two-arm, randomized, double-blind, controlled, multicenter, Phase IIIb trial evaluating the efficacy, safety and tolerability of Rebif in patients with RRMS. A total of 180 patients were randomized in a 2:1 ratio to receive either Rebif 44mcg three times a week subcutaneously, or placebo for an initial period of 16 weeks. At the end of this period, patients from the placebo group were switched in a single-blinded fashion to treatment with Rebif along with the active cohort for a further 24 weeks .

The primary endpoint of the study is the difference between the number of combined unique active magnetic resonance imaging lesions in the two groups at week 16. The trial met this endpoint and the result was statistically-significant (p<0.001). The mean number of lesions per patient was reduced by 69% in the Rebif group compared with those receiving placebo (0.7 versus 2.2). Over half (53%) of patients treated with Rebif had no lesions at week 16, compared to only 16.7% in the placebo group. The firm says results for the secondary and tertiary endpoints of the IMPROVE study will be available at the end of the 40-week treatment period.