Simvastatin treatment in patients with relapsing-remitting multiple sclerosis receiving interferon beta 1a: a double-blind randomized controlled trial

Objectives: This study was conducted to evaluate the effect of simvastatin (40 mg/day) as an adjuvant therapy to interferon beta (IFNb 1a, 30 mu g once weekly) in relapsing-remitting multiple sclerosis patients, compared with placebo. Methods: We enrolled 85 patients with relapsing-remitting multiple sclerosis (71% female) who were already receiving IFNb 1a (Avonex), with Expanded Disability Status Scale score of less than 5.0. The patients were assigned (in random and double-blinded fashion) into the two groups of simvastatin and placebo. All patients continued to receive their current IFNb treatment. The outcome measures were total relapse rate, Expanded Disability Status Scale score, and the number of gadolinium-enhanced (Gd+) and new T2 lesions in magnetic resonance imaging after a 1-year follow-up. We used Mann-Whitney and one-way multivariate analysis of variances to analyze the data. Results: Four patients in the placebo and two in the simvastatin group prematurely withdrew from the study due to experiencing two attacks. The total attack number in the simvastatin group was significantly lower than placebo group (moderate effect size r=0.29) (p=0.01). The final Expanded Disability Status Scale scores were lower in the simvastatin group (1.01 +/- 1.40, mean +/- SD) than in the placebo group (1.73 +/- 1.49, mean +/- SD), but this difference was not significant after controlling the baseline Expanded Disability Status Scale score (p=0.07). In the simvastatin group, the mean +/- SD of gadolinium-enhanced and new T2 lesions were 0.66 +/- 1.18 and 3.39 +/- 3.55, respectively, (compared with 0.74 +/- 1.21 and 3.39 +/- 3.55 in the placebo group). Although there was a decreasing trend in lesions on magnetic resonance imaging, this difference was not statistically significant (p=0.62). The combination therapy was safe and well tolerated, and no serious adverse effect was noted. Conclusion: Our study supports the safety and efficacy of simvastatin as an add-on therapy to INFb 1a in patients with relapsing-remitting multiple sclerosis.