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

Treatment tested

• Tolebrutinib

  Tyrosine-protein kinase BTK inhibitor

Compared with

• Teriflunomide

  Dihydroorotate dehydrogenase inhibitor

Placebo or sham

• Placebo

Other measures (5)

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 fever higher than 38°C and clinically unstable), or recurring systemic infection, as judged by the Investigator * For participants initiating OL tolebrutinib in the LTS17043 study: Participants at risk of developing or having reactivation of hepatitis, ie, results at the unblinding visit (RMS) or opt-in visit (PMS) for serological markers for hepatitis B and C viruses indicating acute or chronic infection * Active alcohol use disorder or a history of alcohol or drug abuse within 1 year prior to the opt-in visit * Current alcohol intake equal to or exceeding the following at the opt-in visit: more than 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 be clinically 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 and planned procedures that may predispose the participant to excessive bleeding during the study, as judged by the Investigator. * For participants initiating OL tolebrutinib in the LTS17043 study: Confirmed unblinding visit (RMS) or opt-in visit (PMS) alanine aminotransferase (ALT) more than 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 by non-liver-related disorder or explained by a stable chronic liver disorder) OR total bilirubin more than 1.5 × ULN (unless due to Gilbert syndrome or non-liver-related disorder). * Acute liver disease, cirrhosis, chronic liver disease (unless considered stable for more than 6 months). * Participants who developed clinically relevant cardiovascular, hepatic, endocrine, neuropsychiatric or other major systemic disease making implementation of the protocol or interpretation of the trial results difficult or that would put the patient at risk by participating in the trial, as judged by the Investigator. * The participant is receiving treatment during the study period with drugs not permitted by the study protocol, including potent and moderate inducers of cytochrome 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

This is a Phase 3 extension, global, multicenter study to assess the long-term safety and tolerability of tolebrutinib in adult participants (aged ≥18 years) with RMS, PPMS, or NRSPMS who were previously enrolled in the Phase 2b LTS (LTS16004) or 1 of the 4 Phase 3 tolebrutinib pivotal trials (GEMINI 1 [EFC16033], GEMINI 2 [EFC16034], HERCULES [EFC16645], or PERSEUS [EFC16035]). SUBSTUDY: ToleDYNAMIC substudy