Early Versus Delayed Start of Ocrevus Zunovo for Relapsing Multiple Sclerosis

Participants With Relapsing Multiple Sclerosis (Rapid-Start and Delayed-Start Cohorts)

Inclusion Criteria:

* Age 18 years or older.
* Diagnosis of relapsing-remitting multiple sclerosis according to the 2017 McDonald criteria.
* At least one gadolinium-enhancing lesion on an MRI of the brain, cervical spine, or thoracic spine within 4 weeks of relapse or hospitalization.

Exclusion Criteria:

* Diagnosis of primary progressive multiple sclerosis.
* Active hepatitis B.
* Current pregnancy.
* Allergy to gadolinium contrast or known allergy to ocrelizumab.
* Unable to complete an MRI.
* Contraindication to or intolerance of oral or intravenous corticosteroids.
* Another known neurological disorder, including a history of progressive multifocal leukoencephalopathy.
* Active bacterial, viral, fungal, or mycobacterial infection, or a history of recurrent aspiration pneumonia requiring antibiotic treatment.
* A condition that may require chronic systemic corticosteroids or immunosuppressants during the study.
* Treatment with an anti-CD20 or other B-cell-depleting therapy within 6 months before enrollment.
* Active cancer or malignancy.
* Prisoner status.
* Limited English-speaking capacity.
* Unable to provide informed consent.

Healthy Control Participants

Inclusion Criteria:

* Age 18 years or older.
* Able and willing to provide written informed consent and undergo study blood draws.
* No diagnosis or history of multiple sclerosis, clinically isolated syndrome, or another inflammatory or demyelinating disorder of the central nervous system.
* In generally good health, as determined by medical history and investigator review.

Exclusion Criteria:

* Multiple sclerosis, clinically isolated syndrome, myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), neuromyelitis optica spectrum disorder (NMOSD), or another neurological disorder that may affect study results.
* An autoimmune, inflammatory, hematologic, or immunodeficiency disorder that may affect B- or T-cell measurements.
* Active bacterial, viral, fungal, or mycobacterial infection at enrollment or blood collection.
* Current use of a disease-modifying therapy, B-cell-depleting therapy, systemic immunosuppressant, immunomodulatory therapy, or chronic systemic corticosteroids.
* Active cancer or malignancy, except adequately treated localized skin cancer if permitted by the investigator.
* Current pregnancy.
* A medical condition that, in the investigator's judgment, could increase risk, interfere with participation, or affect interpretation of immune cell or biomarker results.
* Unable or unwilling to undergo blood collection.
* Prisoner status.
* Limited English-speaking capacity.
* Unable to provide informed consent.