Clinical Study to Compare the Efficacy and Safety of Ponesimod to Placebo in Subjects With Active Relapsing Multiple Sclerosis Who Are Treated With Dimethyl Fumarate (Tecfidera®)

Inclusion Criteria:

- Signed informed consent prior to initiation of any study-mandated procedure.

- Women of childbearing potential must have a negative pregnancy test and use reliable
methods of contraception

- Presenting with a diagnosis of MS as defined by the revised (2010) McDonald Diagnostic
Criteria for MS with relapsing course from onset (i.e., relapsing-remitting multiple
sclerosis (RRMS), or secondary progressive multiple sclerosis (SPMS) with superimposed
relapses).

- Ongoing treatment with DMF for at least 6 months prior to screening

- Active disease after at least 3 months of DMF treatment

- Ambulatory and with an EDSS score between 0 and 6.0 (inclusive).

Exclusion Criteria:

- Lactating or pregnant women and women intending to become pregnant during the study.

- Presenting with a diagnosis of MS with progressive course from onset (i.e., primary
progressive MS or progressive relapsing MS).

- Evidence of a relapse of MS with onset within 30 days prior to baseline EDSS
assessment.

- Any circumstances or conditions, which, in the opinion of the investigator, may affect
full participation in the study or compliance with the protocol.