Multi-center, rater-blinded, parallel-group, two arm, randomized study. Patients with relapsing-remitting forms of MS, respecting all inclusion/exclusion criteria, were randomized in the SWABIMS study in two equal-size parallel arms after three months of treatment with interferon-beta 1b, receiving atorvastatin 40mg/d or not in addition to interferon-beta 1b for 12 month.