Risk of Progressive Multifocal Leukoencephalopathy Among Patients With Multiple Sclerosis Exposed to Zeposia

Inclusion Criteria: * Adverse event (AE) report with MedDRA Preferred Term of " John Cunningham virus (JCV) cerebrospinal fluid test positive", " JCV granule cell neuronopathy", or "Progressive multifocal leukoencephalopathy (PML)" reported to the Sponsor between 4-Jun-2026 and 31-Jul-2041. * AE report(s) originating from spontaneous post-marketing reports, post-marketing observational studies with primary data collection, or patient support programs. * Diagnosis of multiple sclerosis before the initial AE report. * Exposure to at least one dose of ozanimod before onset of PML symptoms. * PML event assessed as "definite" or "probable" by the adjudication committee. * PML assessed as "related" to ozanimod by the adjudication committee. Exclusion Criteria: • There are no additional exclusion criteria.