The investigators intend to examine the effects of ocrelizumab use in African American multiple sclerosis disease course compared to Caucasian disease course utilizing imaging measures with magnetic resonance imaging (MRI) and optical coherence tomography angiography (OCT-A)..

Multiple sclerosis (MS) is a disease of the central nervous system (CNS). Several lines of evidence suggest that MS is an autoimmune disease with both T and B-cell activity leading to CNS inflammation which results in demyelinating injury. Ocrelizumab was FDA approved in March 2017 for relapsing remitting (RRMS) and primary progressive multiple sclerosis (PPMS) by depleting B cells. It has shown to be effective in reducing the annualized relapse rate, decreasing disability progression, and reducing the number of new and active MRI brain lesions.

Previous research studies have reported a more aggressive course in African Americans with MS, more lesions on the MRI scan, and more severe injury to layers of the eye (specifically in the retina) compared to Caucasians.

This is a novel study investigating the effect of ocrelizumab in African American relapsing multiple sclerosis (RMS) patients compared to Caucasian RMS patients using imaging measures, specifically multimodal magnetic resonance imaging (MRI) and optical coherence tomography-angiography (OCTA). This is a non-drug intervention study; therefore, patients who are recruited will have already decided to make ocrelizumab their disease-modifying therapy before enrollment. The study will recruit 86 (including 6 potential screen fails) patients in total (40 African American patients and 40 Caucasian patients who are matched by age, sex, disease duration, and disease disability. The study will consist of 5 visits in six-month intervals across two years.

Inclusion Criteria:

1. Patients who have chosen to start ocrelizumab and for whom ocrelizumab is determined to be the most appropriate standard-of-care disease modifying therapy (DMT) by the treating neurologist.
2. May be treatment naive, or had suboptimal response to no more than one DMT after an adequate course of treatment (defined as treatment duration of 6+ months).
3. Age 18 to 60 years old.
4. Ethnicity: self-identified as African American or Caucasian.
5. Clinically definite relapsing remitting multiple sclerosis (RRMS) per 2017 revised McDonald criteria.
6. EDSS from 0 to 6 (inclusive) at baseline visit.
7. Able to give informed consent.
8. Able to have MRI scans.

Exclusion Criteria:

1. Treatment with another monoclonal antibody, including but not limited to natalizumab, alemtuzumab, daclizumab.
2. Failed 2 or more DMTs.
3. Treatment with immunosuppressant agents, such as chemotherapeutic agents.
4. Claustrophobia.
5. Allergy to contrast.
6. Significant medical problems that the PI determines will interfere with the conduct of the study.
7. Relapse or use of corticosteroids within 30 days prior to baseline visit.
8. Pregnancy.
9. History of kidney or liver insufficiency.
10. History of malignancy.

Participants who are diagnosed with relapsing multiple sclerosis and who have chosen to start or recently started using ocrelizumab as their disease modifying therapy. Age range: 18 to 60 years old. Ethnicity: self-described as African American or Caucasian.

Study protocol, ICFs, study reports, statistical analysis plans, secure CRFs, and results will be shared with Roche/Genentech Inc. All patient data will have a unique number/digit code when sent to protect patient identity.

Data will be available for the duration of the study and up to 15 years after the last patient has completed the study.

All data will be stored and shared in electronic case report form (eCRF) format.