Relapsing Forms of Multiple Sclerosis (RMS) Study of Bruton's Tyrosine Kinase (BTK) Inhibitor Tolebrutinib (SAR442168) (GEMINI 2)

The participant must be 18 to 55 years of age, inclusive, at the time of signing the informed consent

The participant must have been diagnosed with RMS according to the 2017 revision of the McDonald diagnostic criteria

The participant has an expanded disability status scale (EDSS) score ≤5.5 at the first Screening Visit

The participant must have at least 1 of the following prior to screening:

* ≥1 documented relapse within the previous year OR

* ≥2 documented relapses within the previous 2 years, OR

* ≥1 documented Gd enhancing lesion on an MRI scan within the previous year

Contraceptive use by men or women should be consistent with local regulations regarding the methods of contraception for those participating in clinical studies

Male participants are eligible to participate if they agree to the following during the intervention period and until accelerated elimination procedure:

* Refrain from donating sperm

Plus either:

Be abstinent from heterosexual intercourse as their preferred and usual lifestyle (abstinent on a long term and persistent basis) and agree to remain abstinent OR

Must agree to use contraception/barrier as detailed below

Agree to use a male condom and should also be advised of the benefit for a female partner to use a highly effective method of contraception as a condom may break or leak when having sexual intercourse with a woman of childbearing potential (WOCBP) who is not currently pregnant

\- A female participant is eligible to participate if she is not pregnant or breastfeeding, and at least one of the following conditions apply:

Is not a WOCBP OR

Is a WOCBP and agrees to use a contraceptive method that is highly effective (with a failure rate of \<1% per year), preferably with low user dependency during the intervention period and until accelerated elimination procedure is completed (or for at least 10 days after the last dose of SAR442168, if the case was unblinded) and agrees not to donate eggs (ova, oocytes) for the purpose of reproduction during the study and for the same period of time.

* A WOCBP must have a negative highly sensitive pregnancy test at screening and within 24hours before the first dose of study intervention.

* If a urine test cannot be confirmed as negative (eg, an ambiguous result), a serum pregnancy test is required. In such cases, the participant must be excluded from participation if the serum pregnancy result is positive.

* The Investigator is responsible for review of medical history, menstrual history, and recent sexual activity to decrease the risk for inclusion of a woman with an early undetected pregnancy.

* The participant must have given written informed consent prior to undertaking any study related procedure. This includes consent to comply with the requirements and restrictions listed in the informed consent form (ICF) and in this protocol. In countries where the legal age of maturity is greater than 18 years, a specific ICF for such legally minor participants must also be signed by the participant's legally authorized representative

What this study is about