Rare brain infection risk under scrutiny for multiple sclerosis drug ozanimod

This study investigates whether the multiple sclerosis medication ozanimod is linked to a higher risk of progressive multifocal leukoencephalopathy (PML), a rare but serious brain infection caused by the John Cunningham virus. Researchers will review reported cases of PML in people with MS who have taken ozanimod, looking at factors like age, treatment duration, and prior medication use. The goal is to estimate how often PML occurs and identify who might be most at risk.