A Study to Investigate Long-term Safety and Tolerability of Tolebrutinib in Participants With Multiple Sclerosis.

Inclusion Criteria:

• Participants with RMS, PPMS, or NRSPMS who completed the Phase 2b LTS (LTS16004) or 1 of the 4 Phase 3 pivotal tolebrutinib trials (EFC16033, EFC16034, EFC16645, EFC16035) on IMP.

OR

• The Phase 2b LTS (LTS16004) or Phase 3 tolebrutinib pivotal trial participants who temporarily discontinued IMP due to a national emergency and completed the trial visits.

ToleDYNAMIC Substudy: Inclusion criteria are those of the main study

Exclusion Criteria:

• Participants are excluded from the study if any of the following criteria apply:

• The participant is at risk for or has a persistent chronic, active (including feverhigher than 38°C and clinically unstable), or recurring systemic infection, asjudged by the Investigator

• For participants initiating OL tolebrutinib in the LTS17043 study: Participants atrisk of developing or having reactivation of hepatitis, ie, results at theunblinding visit (RMS) or opt-in visit (PMS) for serological markers for hepatitis Band C viruses indicating acute or chronic infection

• Active alcohol use disorder or a history of alcohol or drug abuse within 1 yearprior to the opt-in visit

• Current alcohol intake equal to or exceeding the following at the opt-in visit: morethan 2 drinks per day for men and more than 1 drink per day for women

• Abnormal ECG during the opt-in visit considered in the Investigator's judgment to beclinically significant, such as QTcF >500 msec, in the context of this study.

• A bleeding disorder, known platelet dysfunction, abnormal platelet count (<100,000/microliter), history of significant bleeding event or other conditions andplanned procedures that may predispose the participant to excessive bleeding duringthe study, as judged by the Investigator.

• For participants initiating OL tolebrutinib in the LTS17043 study: Confirmedunblinding visit (RMS) or opt-in visit (PMS) alanine aminotransferase (ALT) morethan 1.5 × upper limit of normal (ULN) OR aspartate aminotransferase (AST) more than 1.5 × ULN OR alkaline phosphatase more than 2 × ULN (unless caused bynon-liver-related disorder or explained by a stable chronic liver disorder) OR totalbilirubin more than 1.5 × ULN (unless due to Gilbert syndrome or non-liver-relateddisorder).

• Acute liver disease, cirrhosis, chronic liver disease (unless considered stable formore than 6 months).

• Participants who developed clinically relevant cardiovascular, hepatic, endocrine,neuropsychiatric or other major systemic disease making implementation of theprotocol or interpretation of the trial results difficult or that would put thepatient at risk by participating in the trial, as judged by the Investigator.

• The participant is receiving treatment during the study period with drugs notpermitted by the study protocol, including potent and moderate inducers ofcytochrome P450 (CYP) 3A or potent inhibitors of CYP2C8 hepatic enzymes.

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

ToleDYNAMIC Substudy: Exclusion criteria are those of the main study