Dose-finding Study for SAR442168 in Relapsing Multiple Sclerosis

Treatment tested

• Tolebrutinib

  Tyrosine-protein kinase BTK inhibitor

• Locally approved intravenous contrast medium for contrast enhanced magnetic resonance imaging (MRI)

Placebo or sham

• Placebo

Other measures (6)

Inclusion criteria: * Participant must be 18 to 55 years of age, inclusive, at the time of signing the informed consent. * Participant was diagnosed with relapsing multiple sclerosis (RMS) according to the 2017 revision of the McDonald diagnostic criteria. * Participant must had at least 1 documented relapse within the previous year, OR greater than or equal to (>=) 2 documented relapses within the previous 2 years, OR >=1 active Gadolinium (Gd) enhancing brain lesion on an MRI scan in the past 6 months and prior to screening. * A female participant must had used a double contraception method including a highly effective method of birth control from inclusion and up to 2 months after the last study dose, except if she had undergone sterilization at least 3 months earlier or was postmenopausal. Menopause was defined as being amenorrheic for >=12 months with serum follicle-stimulating hormone (FSH) level greater than (>) 30 International Units per liters. * Male participants, whose partners were of childbearing potential (including breastfeeding women), must had accepted to use, during sexual intercourse, a double contraceptive method according to the following algorithm: (condom) plus (intrauterine device or hormonal contraceptive) from inclusion up to 3 months after the last dose. * Male participants whose partners were pregnant must had used, during sexual intercourse, a condom from inclusion up to 3 months after the last dose. * Male participants had agreed not to donate sperm from the inclusion up to 3 months after the last dose. * Participant had given written informed consent prior to undertaking any study-related procedure. Exclusion criteria: * The participant had been diagnosed with primary progressive multiple sclerosis according to the 2017 revision of the McDonald diagnostic criteria or with non relapsing secondary progressive multiple sclerosis. * Requirement for concomitant treatment that could bias the primary evaluation. * Contraindication for MRI. * Contraindications to use MRI Gd contrast-enhancing preparations. * History of infection with the human immunodeficiency virus (HIV). * History of active or latent tuberculosis. * Any other active infections that would adversely affect participation or investigational medicinal product administration in this study, as judged by the Investigator. * Presence of any screening laboratory or electrocardiogram values outside normal limits that were considered in the Investigator's judgment to be clinically significant. * Presence of liver injury. * At screening, the participant was positive for hepatitis B surface antigen and/or hepatitis B core antibody and/or was positive for hepatitis C antibody. * Bleeding disorder or known platelet dysfunction at any time prior to screening visit. * Participant had received any live (attenuated) vaccine (including but not limited to varicella zoster, oral polio, and nasal influenza) within 2 months before first treatment visit. * Participant was receiving strong inducers or inhibitors of cytochrome P450 3A (CYP3A) or CYP2C8 hepatic enzymes. * Participant was receiving anticoagulant/antiplatelet therapies. * Participant had taken other investigational drugs within 3 months or 5 half lives, whichever was longer, before screening visit. * Participant had an Expanded Disability Status Scale score >5.5 at first screening visit. * Participant had a relapse in the 30 days prior to randomization. * Participant was pregnant or a breastfeeding woman. * History or presence of significant other concomitant illness. * The participant had received medications/treatments for multiple sclerosis within a specified time frame. The above information was not intended to contain all considerations relevant to a participant's potential participation in a clinical trial.

Primary Objective: To determine the dose-response relationship for SAR442168 to reduce the number of new active brain lesions. Secondary Objectives: * To evaluate efficacy of SAR442168 on disease activity as assessed by imaging measures. * To evaluate the safety and tolerability of SAR442168.