A Study Comparing the Effectiveness and Safety of Teriflunomide and Interferon Beta-1a in Patients With Relapsing Multiple Sclerosis

Primary objective was to assess the effectiveness evaluated by the time to failure of two doses of teriflunomide in comparison to interferon beta-1a in participants with relapsing Multiple Sclerosis \[MS\].

Secondary objectives were:

* To assess the effect of the two doses in comparison to interferon beta-1a on:

  * Frequency of relapses,
  * Fatigue,
  * Participant's satisfaction with treatment.
* To evaluate the safety and tolerability of the two doses in comparison to interferon beta-1a.

The study consisted of a core treatment period with a common end date defined as 48 weeks after randomization of the last participant, followed by an optional long-term extension treatment period until teriflunomide is commercially available in accordance with local regulations.

The core treatment period per participant was variable depending on the enrollment in the study (maximum of approximatively 118 weeks). The two doses of teriflunomide were administered in double-blind fashion, whereas interferon beta-1a (Rebif®) was open-label.

The opportunity to continue with the highest dose of teriflunomide in open-label fashion was offered to the participants who successfully completed treatment in the core study.

The overall treatment period was followed by a 4-week elimination follow-up period.

Eligibility Criteria:
Inclusion Criteria:

* Relapsing form of MS meeting McDonald's criteria for MS diagnosis and Expanded Disability Status Scale \[EDSS\] score ≤5.5 at screening visit.

Exclusion Criteria:

* Significantly impaired bone marrow function or, significant anemia, leukopenia or thrombocytopenia;
* Persistent significant or severe infection.
* Liver function impairment or known history of hepatitis.
* Use of adrenocorticotrophic hormone \[ACTH\] or systemic corticosteroids for 2 weeks prior to randomization.
* Human immunodeficiency virus \[HIV\] positive.
* Prior use of Rebif®, or prior or concomitant use of other interferons in the 3 months prior to randomization.
* Prior or concomitant use of cladribine, mitoxantrone, or other immunosuppressant agents such as azathioprine, cyclophosphamide, cyclosporin, methotrexate, mycophenolate, or natalizumab.
* Pregnant or breast-feeding woman.

Extension criteria:

The participants who met all the following criteria at the end of the core study period were eligible for enrolment into the open-label extension phase:

* Participants who had not discontinued treatment in the core period and who had a minimum treatment of 48 weeks and completed the EOT visit (Visit 18).
* Participants who had not met criteria for treatment withdrawal.
* An informed consent must be obtained in writing from the participant for this open-label extension phase prior to entering and prior to completion of any extension phase procedure.
* Participants who demonstrated a willingness and ability to roll over to the extension phase with the opportunity to continue treatment on 14 mg/day of teriflunomide under open-label.

The above information is not intended to contain all considerations relevant to a participant's potential participation in a clinical trial.