Efficacy and Safety of Remibrutinib Compared to Teriflunomide in Participants With Relapsing Multiple Sclerosis (RMS)

Inclusion Criteria:

1. 18 to 55 years of age
2. Diagnosis of RMS according to the 2017 McDonald diagnostic criteria
3. At least: 1 documented relapse within the previous year. OR 2 documented relapses within the previous 2 years, OR 1 active Gadolinium (Gd)-enhancing lesion in the 12 months.
4. EDSS score of 0 to 5.5 (inclusive)
5. Neurologically stable within 1 month

Exclusion Criteria:

1. Diagnosis of primary progressive multiple sclerosis (PPMS)
2. Disease duration of more than 10 years in participants with EDSS score of 2 or less at screening
3. History of clinically significant CNS disease other than MS
4. Ongoing substance abuse (drug or alcohol)
5. History of malignancy of any organ system (other than complete resection of localized basal cell carcinoma of the skin or in situ cervical cancer),
6. Participants with history of confirmed Progressive Multifocal Leukoencephalopathy (PML) or Neurological symptoms consistent with PML
7. suicidal ideation or behavior
8. Evidence of clinically significant cardiovascular, neurological, psychiatric, pulmonary , renal, hepatic, endocrine, metabolic, hematological disorders or gastrointestinal disease that can interfere with interpretation of the study results or protocol adherence
9. Participants who have had a splenectomy
10. Active clinically significant systemic bacterial, viral, parasitic or fungal infections
11. Positive results for syphilis or tuberculosis testing
12. Uncontrolled disease states, such as asthma, or inflammatory bowel disease, where flares are commonly treated with oral or parenteral corticosteroids
13. Active, chronic disease of the immune system (including stable disease treated with immune therapy (e.g. Leflunomide, Methotrexate)) other than MS (e.g. rheumatoid arthritis, systemic lupus erythematosus, etc.) with the exception of well-controlled diabetes or thyroid disorder.
14. Participants with a known immunodeficiency syndrome (AIDS, hereditary immune deficiency, drug induced immune deficiency), or tested positive for HIV antibody
15. History or current treatment for hepatic disease including but not limited to acute or chronic hepatitis, cirrhosis or hepatic failure or participants with moderate or severe hepatic impairment (Child-Pugh class C) or any chronic liver or biliary disease.
16. History of severe renal disease or creatinine level
17. Participants at risk of developing or having reactivation of hepatitis
18. Hematology parameters at screening:

1. Hemoglobin: < 10 g/dl (<100g/L)
2. Platelets: < 100000/mm3 (<100 x 109/L)
3. Absolute lymphocyte count < 800/mm3 (<0.8 x 109/L)
4. White blood cells: <3 000/mm3 (<3.0 x 109/L)
5. Neutrophils: < 1 500/mm3 (<1.5 x 109/L)
6. B-cell count < 50% lower limit of normal (LLN) or total IgG & total IgM < LLN (only required for participants who had a history of receiving B-cell therapies, such as rituximab, ocrelizumab or ofatumumab, prior to screening)
7. History or current diagnosis of significant ECG abnormalities
8. Resting QTcF ≥450 msec (male) or ≥460 msec (female) at pre-treatment (prior to randomization)
9. Use of other investigational drugs
10. Requirement for anticoagulant medication or use of dual anti-platelet therapy Significant bleeding risk or coagulation disorders,
11. History of gastrointestinal bleeding
12. Major surgery within 8 weeks prior to screening
13. History of hypersensitivity to any of the study drugs or excipients
14. Pregnant or nursing (lactating) female participants, prior to randomization
15. Women of childbearing potential not using highly effective contraception
16. Sexually active males not agreeing to use condom
17. Have received any live or live-attenuated vaccines within 6 weeks of randomization or requirement to receive these vaccinations during study
18. Use of strong CYP3A4 inhibitors or use of moderate or strong CYP3A4 inducers within two weeks prior to randomization

Inclusion to Extension part:

• Participants who complete the Core Part of the study on double-blind study treatment and conduct the Accelerated Elimination Procedure (AEP)

Other inclusion and exclusion criteria may apply.