The primary objective is to directly estimate brain glutathione concentrations in vivo using H-MRS at 7T before and after initiation of Tecfidera in established multiple sclerosis (MS) patients considering switching therapy or being treatment-naive (first line).

Inclusion Criteria:

• Male or female adult patients
• 18-60 years of age
• Diagnosis of multiple sclerosis, in accordance with the revised McDonald criteria (2010)
• Patients naive to MS therapy or patients switching from an FDA-approved MS therapy, including IFN-B formulations, Cop-1, Teriflunomide, and Fingolimod to BG-12
• Expanded Disability Status Scale (EDSS) score 0 to 5.5 inclusive

Exclusion Criteria:

• Primary progressive multiple sclerosis patients
• Patients with previous exposure or known allergies to fumarates
• MS patients switching from natalizumab, cyclophosphamide, or mitoxantrone to BG-12
• Contraindications for MRI/MRS
• Known presence of other neurological disorders that may mimic multiple sclerosis
• Pregnancy or lactation
• Requirement for chronic treatment with systemic corticosteroids or immunosuppressants during the course of the study
• History of or currently active primary or secondary immunodeficiency
• Active infection, or history of or known presence of recurrent or chronic infection (e.g. hepatitis B or C, HIV, syphilis, tuberculosis_
• History of progressive multifocal leukoencephalopathy
• Contraindications to or intolerance of oral or intravenous (IV) corticosteroids

Patients with a relapsing form of MS