ARR is the total number of confirmed relapses that occurred during the treatment period divided by the total number of patient-years treated. Each episode of relapse (appearance, or worsening of a clinical symptom that was stable for at least 30 days, that persisted for a minimum of 24 hours in the absence of fever) was to be confirmed by an increase in Expanded Disability Status Scale (EDSS) score or Functional System scores. To account for the different treatment durations among participants, a Poisson regression model with robust error variance was used (total number of confirmed relapses as response variable; log-transformed treatment duration as "offset" variable; treatment group, region of enrollment and IFN-beta dose stratum, and number of relapses in the year prior to randomization as covariates).

Intent-to-treat (ITT) population: all randomized and treated participants. Participants were considered in the treatment group to which they were randomized regardless of the drug they actually received.

Number of Gd-enhancing T1-lesions per scan is the total number of Gd-enhancing T1-lesions that occurred during the treatment period divided by the total number of scans performed during the treatment period. To account for the different number of scans among participants, a Poisson regression model with robust error variance was used (total number of Gd-enhancing T1-lesions as response variable; log-transformed number of scans as offset variable; treatment group, region of enrollment, IFN-beta dose stratum and baseline number of Gd-enhancing T1-lesions as covariates).

ITT population as previously defined but including only participants who had post-baseline data.

The 12-week sustained disability progression was defined as an increase from baseline of at least 1-point in EDSS score (at least 0.5-point for participants with baseline EDSS score >5.5) that persisted for at least 12 weeks. Probability of disability progression was to be estimated using Kaplan-Meier method.

Data for this outcome was not analyzed because of insufficient data after early study termination.

Total volume of Gd-enhancing T1-lesions per scan is the sum of the volumes of Gd-enhancing T1-lesions observed during the treatment period divided by the total number of scans performed during the treatment period.

ITT population as previously defined but including only participants who had post-baseline data.

The total lesion volume (burden of disease) is the total volumes of hyperintense on T2 plus hypointense on T1 as measured by MRI scan. Least-square means were estimated using a Mixed-effect model with repeated measures (MMRM) on cubic root transformed volume data with factors for treatment, region, IFN-beta dose stratum, visit, treatment-by-visit interaction, cubic root transformed baseline burden of disease, and baseline-by-visit interaction.

ITT population as previously defined but including only participants who had post-baseline data.

Probability of no relapse at 24, 48 and 72 weeks was estimated using Kaplan-Meier method on the time to relapse defined as the time from randomization to first EDSS confirmed relapse. Participants free of confirmed relapse (no EDSS confirmed relapse observed on treatment) were censored at the date of the last study drug intake. Kaplan-Meier method consists in computing probabilities of non-occurrence of event at any observed time of event and multiplying successive probabilities for time <=t by any earlier computed probabilities to estimate the probability of being event-free for the amount of time t.

ITT population as previously defined.

FIS is a participant-reported scale that qualifies the impact of fatigue on daily life in participants with MS.

Data for this outcome was not analyzed because of insufficient data after early study termination.

SF-36 scale is a generic, self-administered, health-related quality-of-life (QOL) instrument.

Data for this outcome was not analyzed because of insufficient data after early study termination.

Resource utilization each time a participant experiences an MS relapse, specifically the number of hospitalizations, the number of over night spent in the hospital and number of intensive care admissions if hospitalized were to be reported.

Data for this outcome was not analyzed because of insufficient data after early study termination.

AEs are any unfavorable and unintended sign, symptom, syndrome, or illness observed by the investigator or reported by the participant during the study.

Safety population: all randomized and treated participants. Participants were included in the treatment group according to the drug actually received.The participant randomized to Teriflunomide 14 mg group who received Teriflunomide 7 mg was analyzed in the Teriflunomide 7 mg group.

PCSA values are abnormal values considered medically important by the Sponsor according to predefined criteria based on literature review. Hepatic parameters thresholds were defined as follows: Alanine Aminotransferase (ALT) >3, 5 or 10 Upper Limit of Normal (ULN); Aspartate Aminotransferase (AST) >3, 5 or 10 ULN; Alkaline Phosphatase >1.5 ULN; Total Bilirubin (TB) >1.5 ULN; and ALT >3 ULN and TB >2 ULN.

Safety population as previously defined but including only participants who had post-baseline values.