TERACLES

Treatment tested

• Teriflunomide

  Dihydroorotate dehydrogenase inhibitor

• Interferon beta

Placebo or sham

• Placebo (for teriflunomide)

Other measures (10)

Inclusion criteria : * Patient with relapsing forms of MS treated with IFN-beta * Stable dose of IFN-beta (approved brand) for at least 6 months prior to randomization * Disease activity in the 12 months prior to randomization and after first 3 months of IFN-beta treatment (defined by at least 1 relapse supported by EDSS or equivalent neurological examination, or, at least 1 brain or spinal cord MRI with at least one T1 gadolinium enhancing lesion) Exclusion criteria: * McDonald criteria for MS diagnosis not met at time of screening visit * EDSS score greater than (>) 5.5 at randomization visit * A relapse within 30 days prior randomization * Persistent significant or severe infection * Patients must not have used adrenocorticotrophic hormone or systemic corticosteroids for 2 weeks prior to randomization * Prior or concomitant use of cytokine therapy (except baseline interferons), glatiramer acetate or intravenous immunoglobulins in the 3 months preceding randomization * Liver function impairment or persisting elevations (confirmed by retest) of alanine aminotransferase (ALT), aspartate aminotransferase (AST), or direct bilirubin greater than 2 times the upper limit of normal range (ULN) * Active hepatitis or hepatobiliary disease or known history of severe hepatitis * Pregnant or breast-feeding women or those who were planning to become pregnant during the study * Significantly impaired bone marrow function or significant anemia, leukopenia, or thrombocytopenia * Human Immunodeficiency Virus (HIV) positive * Known history of active tuberculosis not adequately treated * Prior use within 2 years preceding randomization or concomitant use of cladribine and mitoxantrone * Prior use within 6 months preceding randomization or concomitant use of natalizumab, or any other immunosuppressive agents such as azathioprine, cyclophosphamide, cyclosporine, methotrexate, mycophenolate, or fingolimod The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.

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)