A Multi-center Double-blind Parallel-group Placebo-controlled Study of the Efficacy and Safety of Teriflunomide in Patients With Relapsing Multiple Sclerosis Who Are Treated With Interferon-beta

The primary objective was to demonstrate the effect of teriflunomide, in comparison to placebo, on frequency of Multiple Sclerosis (MS) relapses in patients with relapsing forms of MS who are treated with Interferon-beta (IFN-beta).The secondary objectives were:* Assess the effect of teriflunomide, in comparison to placebo, when added to IFN-beta on: * Disease activity as measured by brain Magnetic Resonance Imaging (MRI) * Disability progression * Burden of disease and disease progression as measured by brain MRI* Evaluate the safety and tolerability of teriflunomide when added to IFN-beta therapy* Assess the pharmacokinetics of teriflunomide in use in addition to baseline IFN-beta therapy* Assess associations between variations in genes and clinical outcomes (safety and efficacy)* Assess other measures of efficacy of teriflunomide such as fatigue and health-related quality of life* Assess measures of health economics (hospitalization due to relapse, including the length of stay and any admission to intensive care unit)