Lessons learned after 20 years of real-world experience with natalizumab.

Background: While natalizumab (NTZ) is an effective therapy for multiple sclerosis (MS), it is associated with an increased risk of progressive multifocal leukoencephalopathy (PML). After 20 years (2002-2022) of experience with NTZ at our center, we observed no cases of PML.

Objectives: We evaluated the likelihood of experiencing PML in a subset of our treatment cohort, as well as reviewed treatment practices at our center that may mitigate PML risk.