ARR: number of confirmed relapses per patient-year. Relapse: new, worsening, or recurrent neurological symptoms that occurred at least 30 days after the onset of a preceding relapse, and that lasted at least 24 hours, in the absence of fever or infection. A confirmed relapse is identified when a patient's symptoms worsen as indicated by an increase in their Expanded Disability Status Scale (EDSS) or Functional Systems (FS) scores, consistent with previous clinically stable assessments. Specific criteria for a confirmed relapse include: An increase of 0.5 points on EDSS; (unless EDSS=0, then requires an increase of 1.0-point); An increase of at least 1.0 point in at least two FS scores; or a 2.0-point increase in one FS score (excluding bladder/bowel and cerebral). Rating individual FS scores is used to rate EDSS along with observations and information concerning gait and use of assistance. EDSS is ordinal clinical rating scale ranging:0 (normal)-10 (death due to MS).

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study.

Time to first confirmed relapse: date of first confirmed relapse (in either core or extension study) minus date of randomization in core study+1 day. Relapse: new, worsening, or recurrent neurological symptoms that occurred at least 30 days after the onset of a preceding relapse, and that lasted at least 24 hours in absence of fever or infection. A confirmed relapse: when patient's symptoms worsen as indicated by an increase in their EDSS/FS scores, consistent with previous clinically stable assessments. Specific criteria for confirmed relapse are: An increase of 0.5 points on EDSS; (unless EDSS=0, then requires an increase of 1.0-point); An increase of at least 1.0 point in at least two FS scores; or a 2.0-point increase in one FS score (excluding bladder/bowel and cerebral). Rating individual FS scores is used to rate EDSS along with observations and information concerning gait and use of assistance. EDSS is ordinal clinical rating scale ranging:0(normal)-10(death due to MS).

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study.

Time to first 12-week CDA is defined as start date of the first 12-week CDA minus date of randomization in the core study + 1 day. A 12-week CDA is defined as a 12-week sustained increase from the core baseline EDSS score, which is confirmed at a scheduled visit after 12-weeks. CDA is defined as: (a) Sustained increase of at least 1.5 in EDSS for participants with a core baseline EDSS score of 0; (b) Sustained increase of at least 1.0 in EDSS for participants with a core baseline EDSS score of 1.0 to 5.0; (c) Sustained increase of at least 0.5 in EDSS for participants with a core baseline EDSS score >=5.5, confirmed after 12 weeks. EDSS is an ordinal clinical rating scale ranging from 0 (normal neurological examination) to 10 (death due to MS). Core baseline for efficacy: last non-missing value recorded before or on randomization in the core study for each outcome measure and participant individually.

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study.

Time to first 24-week CDA was defined as start date of the first 24-week CDA minus date of randomization in the core study + 1 day. A 24-week CDA was defined as a 24-week sustained increase from the core baseline EDSS score, which is confirmed at a scheduled visit after 24-weeks. CDA was defined as: (a) Sustained increase of at least 1.5 in EDSS for participants with a core baseline EDSS score of 0; (b) Sustained increase of at least 1.0 in EDSS for participants with a core baseline EDSS score of 1.0 to 5.0; (c) Sustained increase of at least 0.5 in EDSS for participants with a core baseline EDSS score >=5.5, confirmed after 24 weeks. EDSS was an ordinal clinical rating scale ranging from 0 (normal neurological examination) to 10 (death due to MS). Core baseline for efficacy: last non-missing value recorded before or on randomization in the core study for each outcome measure and participant individually.

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study.

Relapse: new, worsening, or recurrent neurological symptoms that occurred at least 30 days after the onset of a preceding relapse, and that lasted at least 24 hours in absence of fever or infection. A confirmed relapse: when patient's symptoms worsen as indicated by an increase in their EDSS/FS scores, consistent with previous clinically stable assessments. Specific criteria for confirmed relapse: An increase of 0.5 points on EDSS; (unless EDSS=0, then requires an increase of 1.0-point); An increase of at least 1.0 point in at least two FS scores; or a 2.0-point increase in one FS score (excluding bladder/bowel and cerebral). Rating individual FS scores is used to rate EDSS along with observations and information concerning gait and use of assistance. EDSS is ordinal clinical rating scale ranging:0(normal)-10(death due to MS). Core baseline for efficacy: last non-missing value recorded before or on randomization in the core study for each outcome measure and participant individually.

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study.

EDSS is ordinal clinical rating scale based on standard neurological examination for assessing neurological disability and impairment in MS. Seven FS scores were rated on a scale ranged from 0 to 5 or 6 to assess visual, brain, stem, pyramidal, cerebellar, sensory, bowel and bladder, and cerebral functions while ambulation was scored on scale ranged from 0 to 12 to assess walking distance and assistance. Individual FS scores were then used in conjugation with ambulation score to obtain EDSS score which ranged from 0 (normal) to 10 (death due to MS) in 0.5 unit increments that represented higher levels of disability. Core baseline for efficacy is defined as the last non-missing value recorded before or on randomization in the core study for each outcome measure and each participant individually.

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study. Here, 'N' (number of participants analyzed) signifies number of participants evaluable for this outcome measure.

NEDA-3 up to extension EOS is defined by the absence of confirmed relapse, gadolinium-enhancing (Gd+ T1) lesions, new or enlarging T2 lesions, and 12-week CDA. If at least one of the criteria was not fulfilled or the participant discontinued treatment prematurely, the participant was not considered to have achieved NEDA-3. Confirmed relapse: when patient's symptoms worsen as indicated by an increase in their EDSS/FS scores, consistent with previous clinically stable assessments. Rating individual FS scores is used to rate EDSS along with observations and information concerning gait and use of assistance. EDSS is ordinal clinical rating scale ranging: 0 (normal)-10 (death due to MS). Core baseline for efficacy is defined as the last non-missing value recorded before or on randomization in the core study for each outcome measure and each participant individually.

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study. Here, 'N' (number of participants analyzed) signifies number of participants evaluable for this outcome measure.

NEDA-4 up to EOS is defined by the absence of confirmed relapse, Gd+ T1 lesions, new or enlarging T2 lesions, 12-week CDA until EOS, and absence of annual brain volume decrease >=0.4% from core baseline up to extension EOS. If at least one of the criteria was not fulfilled or the participant discontinued treatment prematurely, the participant was not considered to have achieved NEDA-4. Confirmed relapse: when patient's symptoms worsen by an increase in their EDSS/FS scores, consistent with previous clinically stable assessments. Rating individual FS scores is used to rate EDSS along with observations and information concerning gait and use of assistance. EDSS is ordinal clinical rating scale ranging: 0 (normal)-10 (death due to MS). Core baseline for efficacy is defined as the last non-missing value recorded before or on randomization in core study for each outcome measure and each participant individually.

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study. Here, 'N' (number of participants analyzed) signifies number of participants evaluable for this outcome measure.

Percent change from baseline in brain volume (PCBV) measured by MRI were reported. Normalized Brain Volume at core baseline was measured in cubic centimeter (cm^3). Core baseline for efficacy is defined as the last non-missing value recorded before or on randomization in the core study for each outcome measure and each participant individually. In this outcome measure, results were presented for extension end of treatment visit.

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study. Here, 'N' (number of participants analyzed) signifies number of participants evaluable for this outcome measure.

CUALs was calculated as sum of new T1 Gadolinium-enhanced (Gd+) lesions and new or enlarging T2 lesions (without double-counting of lesions) from baseline up to extension EOS based on the Magnetic resonance imaging (MRI). Average number of lesions per patient-year were reported. Results are based on a negative-binomial regression model. Core baseline for efficacy is defined as the last non-missing value recorded before or on randomization in the core study for each outcome measure and each participant individually.

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study. Here, 'N' (number of participants analyzed) signifies number of participants evaluable for this outcome measure.

Number of Gd+ T1 lesions measured by MRI were reported. Results are based on a negative-binomial regression model. Core baseline for efficacy is defined as the last non-missing value recorded before or on randomization in the core study for each outcome measure and each participant individually. For this outcome measure, results presented here are for the Extension end-of-treatment visit.

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study. Here, 'N' (number of participants analyzed) signifies number of participants evaluable for this outcome measure.

Cumulative number of new or enlarging T2 lesions measured by MRI were reported. Average number of lesions per year were reported. Results are based on a negative-binomial regression model. Core baseline for efficacy is defined as the last non-missing value recorded before or on randomization in the core study for each outcome measure and each participant individually.

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study. Here, 'N' (number of participants analyzed) signifies number of participants evaluable for this outcome measure.

Change from baseline in volume of MRI lesions (T2 lesions, T1 hypointense lesions) were reported. Core baseline for efficacy is defined as the last non-missing value recorded before or on randomization in the core study for each outcome measure and each participant individually. In this outcome measure, results were presented for extension end of treatment visit.

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study. Here, 'N' (number of participants analyzed) signifies number of participants evaluable for this outcome measure. Here, 'n' (number analyzed) is defined as participants analyzed at specified categories.

Number of participants with absence of MRI lesions (Gd+ T1 lesions, new or enlarging T2 lesions) were reported. Core baseline for efficacy is defined as the last non-missing value recorded before or on randomization in the core study for each outcome measure and each participant individually. In this outcome measure, results were presented for extension end of treatment visit.

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study. Here, 'N' (number of participants analyzed) signifies number of participants evaluable for this outcome measure. Here, 'n' (number analyzed) is defined as participants analyzed at specified categories.

Percentage of Gd+ lesions at baseline evolving to PBHs were reported. Core baseline for efficacy is defined as the last non-missing value recorded before or on randomization in the core study for each outcome measure and each participant individually. In this outcome measure, results were presented for extension end of treatment visit.

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study. Here, 'N' (number of participants analyzed) signifies number of participants evaluable for this outcome measure.

Number of participants with TEAEs were reported. An AE is any untoward medical event that occurs in a participants being administered an investigational product, and it does not necessarily indicate only events with clear causal relationship with the relevant investigational product. TEAEs are defined as AEs occurring from start of treatment up to treatment end date + 15 days.

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study.

Number of participants with treatment-emergent new morphological ECG abnormalities were reported. Treatment-emergent new morphological ECG abnormalities are defined as those ECG abnormalities occurring from start of treatment up to treatment end date + 15 days.

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study.

Actual values of 12-lead ECG measurements up to end of study treatment: heart rate were reported. In this outcome measure, results were presented for extension end of treatment visit.

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study. Here, 'N' (number of participants analyzed) signifies number of participants evaluable for this outcome measure.

Actual values of 12-lead ECG measurements up to end of study treatment: PR, QRS, QT, QTcB, QTcF were reported. In this outcome measure, results were presented for extension end of treatment visit.

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study. Here, 'N' (number of participants analyzed) signifies number of participants evaluable for this outcome measure.

Change in heart rate (HR) from baseline up to end of study treatment were reported.

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study. Here, 'N' (number of participants analyzed) signifies number of participants evaluable for this outcome measure.

Change in PR, QRS, QT, QTcB, QTcF from baseline up to end of study treatment were reported.

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study. Here, 'N' (number of participants analyzed) signifies number of participants evaluable for this outcome measure.

Absolute values in FEV1 and FVC values were reported. FEV1: the maximal volume of air exhaled from the lungs in 1 second of a forced expiration from a position of full inspiration as measured by spirometer. FVC: the volume of air (in liters) that can be forcibly blown out after full inspiration in the upright position. Extension baseline for safety is the last valid non-missing assessment that is taken on or after EOT visit in the core study, and prior to first study drug intake in the extension study. Results are presented for extension end of treatment visit.

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study. Here, 'N' (number of participants analyzed) signifies number of participants evaluable for this outcome measure.

Percent change in FEV1 and FVC from baseline (%) were reported. FEV1: the maximal volume of air exhaled from the lungs in 1 second of a forced expiration from a position of full inspiration as measured by spirometer. FVC: the volume of air (in liters) that can be forcibly blown out after full inspiration in the upright position. Extension baseline for safety is the last valid non-missing assessment that is taken on or after EOT visit in the core study, and prior to first study drug intake in the extension study. In this outcome measure, results were presented for extension end of treatment visit.

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study. Here, 'N' (number of participants analyzed) signifies number of participants evaluable for this outcome measure.

Number of participants with treatment-emergent SAEs were reported. A SAE was defined as any untoward medical occurrence that results in death, is life-threatening, requires inpatient hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity, leads to a congenital anomaly/birth defect in the offspring of a participant, or was an important medical event. Treatment-emergent SAEs are defined as SAEs occurring from start of treatment up to treatment end date + 15 days.

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study.

Number of participants with treatment-emergent AESIs were reported. AESIs included bradyarrhythmia occurred post-first dose, macular edema, bronchoconstriction, severe liver injury, serious opportunistic infections including progressive multifocal leukoencephalopathy (PML), skin cancer, non-skin malignancy, convulsions, unexpected neurological or psychiatric symptoms/signs (posterior reversible encephalopathy syndrome [PRES], acute disseminated encephalomyelitis [ADEM], and atypical MS relapses). Treatment-emergent AESIs are defined as AESIs occurring from start of treatment up to treatment end date + 15 days.

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study.

Number of participants with AE leading to premature discontinuation of study treatment were reported. An AE is any untoward medical event that occurs in a participant being administered an investigational product, and it does not necessarily indicate only events with clear causal relationship with the relevant investigational product. TEAEs are defined as AEs occurring from start of treatment up to treatment end date + 15 days.

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study.

Number of participants with treatment-emergent decrease from baseline >20% and >30% in FEV1 or FVC were reported. Treatment-emergent is defined as events occurring from start of treatment up to treatment end date + 15 days (that is, findings not present at any assessment prior to first treatment in the extension study).

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study. Here, 'N' (number of participants analyzed) signifies number of participants evaluable for this outcome measure.

Number of participants with treatment-emergent decrease of >20% points in percent predicted FEV1 and FVC from baseline were reported. Treatment-emergent is defined as events occurring from start of treatment up to treatment end date + 15 days (that is, findings not present at any assessment prior to first treatment in the extension study).

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study. Here, 'N' (number of participants analyzed) signifies number of participants evaluable for this outcome measure.

Number of participants with a decrease of >=200 mL or >=12% in FEV1 or FVC from baseline to EOT were planned to be reported. Extension baseline for safety is the last valid non-missing assessment that is taken on or after EOT visit in the core study, and prior to first study drug intake in the extension study. This endpoint is not relevant as a substantial proportion of patients continued onto post-treatment disease-modifying therapy (DMT), hence it cannot provide an assessment of reversibility.

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study.

Change in FEV1 and FVC (% predicted) from baseline to EOT were predicted. Extension baseline for safety is the last valid non-missing assessment that is taken on or after EOT visit in the core study, and prior to first study drug intake in the extension study.

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study. Here, 'N' (number of participants analyzed) signifies number of participants evaluable for this outcome measure.

Change in FEV1 and FVC (% predicted) from baseline to EOS were predicted. Extension baseline for safety is the last valid non-missing assessment that is taken on or after EOT visit in the core study, and prior to first study drug intake in the extension study.

The extension set included all participants who signed an informed consent to enter the extension study and who received at least one dose of ponesimod study medication in the extension study. Here, 'N' (number of participants analyzed) signifies number of participants evaluable for this outcome measure.

Absolute change in lung diffusion capacity as assessed by DL[CO] from baseline were reported. Extension baseline for safety is the last valid non-missing assessment that is taken on or after EOT visit in the core study, and prior to first study drug intake in the extension study.

The DL[CO] sub-study extension set included all participants in the extension set who have consented to participate in the DL[CO] sub-study during the extension study. Here, 'N' (number of participants analyzed) signifies number of participants evaluable for this outcome measure.

Change in DL[CO] (% predicted) from baseline to EOT were predicted. Extension baseline for safety is the last valid non-missing assessment that is taken on or after EOT visit in the core study, and prior to first study drug intake in the extension study.

The DL[CO] sub-study extension set includes all participants in the extension set who have consented to participate in the DL[CO] sub-study during the extension study. Here, 'N' (number of participants analyzed) signifies number of participants evaluable for this outcome measure.

Change in DL[CO] (% predicted) from baseline to EOS were predicted. Extension baseline for safety is the last valid non-missing assessment that is taken on or after EOT visit in the core study, and prior to first study drug intake in the extension study.

The DL[CO] sub-study extension set includes all participants in the extension set who have consented to participate in the DL[CO] sub-study during the extension study. Here, 'N' (number of participants analyzed) signifies number of participants evaluable for this outcome measure.

Actual values of 12-lead ECG measurements on day of first Re-initiation (Day 1) of study drug: heart rate were reported.

Population analysis included numbers of participants based on sub-set of extension set who had a re-initiation. Here, 'n' (number analyzed) is defined as participants analyzed at specified timepoints.

Actual values of 12-lead ECG measurements on day of first Re-initiation (Day 1) of study drug: PR, QRS, QT, QTcB, QTcF were reported.

Population analysis included numbers of participants based on sub-set of extension set who had a re-initiation. Here, 'n' (number analyzed) is defined as participants analyzed at specified timepoints.