Conversion to CDMS was defined by the occurrence of a relapse, which was defined as a new neurological abnormality separated by at least 30 days from onset of a preceding clinical event, presented for at least 24 hours and occurred in the absence of fever or known infection. Percent probability of conversion at 24, 48, and 108 weeks was estimated using Kaplan-Meier method.

Intent-to-treat (ITT) population included all randomized participants who had at least 1 day study medication exposure. Participants were analyzed in the treatment group to which they were randomized.

Conversion to DMS was demonstrated by dissemination of MRI lesions in time (as per McDonald criteria) or a relapse, whichever occurs first. MRI Imaging criteria were detection of Gadolinium (Gd) enhancement at least 3 months after onset of initial clinical event, if not at site corresponding to initial event; detection of new T2 lesion if it appears at any time compared with reference scan (done at time of screening) done at least 30 days after onset of the initial clinical event. Occurrence of relapse was defined as new neurological abnormality separated by at least 30 days from onset of preceding clinical event, present for at least 24 hours and occurring in absence of fever or known infection. New clinical abnormality (neurological sign) that is consistent with participant's symptoms with increase in at least one Functional System (FS) or EDSS score compared to last EDSS assessment. Percent probability of conversion at 24, 48, and 108 weeks was estimated using Kaplan-Meier method.

ITT population.

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 EDSS score or Functional System scores. ARR was assessed using Poisson regression model with robust error variance. To account for the different treatment durations among participants, a Poisson regression model with robust error variance was used (total number of confirmed relapses onset between randomization date and last dose date as the response variable, treatment, region and baseline monofocal/multifocal status as covariates, and log-transformed treatment duration as an offset variable).

ITT population.

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, baseline monofocal/multifocal status, region, visit, treatment-by-visit interaction, cubic root transformed baseline burden of disease, and baseline-by-visit interaction.

ITT population, but including only participants who had post-baseline data.

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 numbers of scans performed among the participants, a Poisson regression model with robust error variance was used (total number of Gd-enhancing T1-lesions as response variable, treatment, baseline monofocal/multifocal status, region and baseline number of Gd-enhancing T1-lesions as covariates, and log-transformed number of scans as an offset variable).

ITT population, but including only participants who had post-baseline data.

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. To account for the different numbers of scans performed among the participants, a Poisson regression model with robust error variance was used (total number of Gd-enhancing T1-lesions as response variable, treatment, baseline monofocal/multifocal status, region and baseline number of Gd-enhancing T1-lesions as covariates, and log-transformed number of scans as an offset variable).

ITT population, but including only participants who had post-baseline data.

Volume of hypointense post-gadolinium T1 lesion component was measured by MRI scan. Least-square means were estimated using a Mixed-effect model with repeated measures (MMRM) on cubic root transformed volume data adjusted for baseline monofocal/multifocal status, region, visit, treatment-by-visit interaction, cubic root transformed baseline value, and baseline-by-visit interaction

ITT population, but including only participants who had post-baseline data.

Volume of T2 lesion component was measured by MRI scan. Least-square means were estimated using a Mixed-effect model with repeated measures (MMRM) on cubic root transformed volume data adjusted for baseline monofocal/multifocal status, region, visit, treatment-by-visit interaction, cubic root transformed baseline value, and baseline-by-visit interaction.

ITT population, but including only participants who had post-baseline data.

Atrophy was measured by MRI scan.

ITT population, but including only participants who had post-baseline data.

The 12-week sustained disability progression was defined as increase from baseline of at least 1-point in EDSS score (at least 0.5-point for participants with baseline EDSS score of greater than [>] 5.5) that persisted for at least 12 weeks. Percent probability of participants free of 12-week sustained disability progression at 24, 48, and 108 weeks was estimated using Kaplan-Meier method.

ITT population.

EDSS is an ordinal scale in half-point increments that qualifies disability in participants with MS. It consists of 8 ordinal rating scales assessing seven functional systems (visual, brainstem, pyramidal, cerebellar, sensory, bowel/bladder and cerebral) as well as ambulation. EDSS total score ranges from 0 (normal neurological examination) to 10 (death due to MS). Least-square means were estimated using a Mixed-effect model with repeated measures (MMRM) on cubic root transformed volume data adjusted for baseline monofocal/multifocal status, region, visit, treatment-by-visit interaction, baseline value and baseline-by-visit interaction

ITT population, but including only participants who had post-baseline data.

FIS is a participant-reported scale that qualifies the impact of fatigue on daily life in participants with MS. It consists of 40 statements that measure fatigue in three areas; physical, cognitive, and social. FIS total score ranges from 0 (no problem) to 160 (extreme problem). Least-square means were estimated using a Mixed-effect model with repeated measures [MMRM] on FIS total score data adjusted for or baseline monofocal/multifocal status, region, visit, treatment-by-visit interaction, baseline value and baseline-by-visit interaction.

ITT population, but including only participants who had post-baseline data.

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 participants exposed to study medication; analyzed according to drug actually received. In Placebo arm, 4 received teriflunomide 7mg & 2 received teriflunomide 14mg, hence they were included in respective teriflunomide arm. Participants who were randomized but not treated were excluded (2 in each teriflunomide arm).

Conversion to CDMS was defined by the occurrence of a relapse, which was defined as a new neurological abnormality separated by at least 30 days from onset of a preceding clinical event, presented for at least 24 hours and occurred in the absence of fever or known infection. Percent probability of conversion was estimated using Kaplan-Meier method.

ITT Population: all randomized participants in the extension who had at least 1 day IMP exposure. Participants were analyzed according to the treatment group allocated by the randomization in the core study followed by the re-randomized treatment group during the extension period.

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 included all randomized population who actually received at least 1 dose of the IMP in extension and analyzed according to the treatment actually received in core study followed by treatment actually received in the extension treatment period.

Analysis was performed on Safety population. In Placebo/teriflunomide 7mg arm, 2 received 7mg in the core period; In Placebo/teriflunomide 14mg, 1 received 7mg in the core period, hence, they were included in the 7mg/7mg arm in extension period as treatment received in the core period for consistency.

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, 10 or 20 upper limit of normal(ULN);
• Aspartate aminotransferase (AST) >3, 5, 10 or 20 ULN;
• Alkaline Phosphatase >1.5 ULN;
• Total Bilirubin (TB) >1.5, 2, or 3 ULN;
• ALT >3 ULN and TB >2 ULN.

Safety population as described in Outcome Measure 13. Here 'n' signifies the number of participants for the treatment group who had that parameter assessed at post-baseline.