Use of natalizumab in persons with multiple sclerosis: 2022 update.

BACKGROUND: Natalizumab is a humanized monoclonal antibody used for treatment of highly active relapsing-remitting multiple sclerosis (MS). With more than 15 years of post-marketing experience with natalizumab in Canada, several real-world studies have shown the long-term efficacy and safety of natalizumab. In addition, risk stratification/mitigation strategies for progressive leukoencephalopathy (PML), an adverse effect associated with natalizumab based on the John Cunningham virus (JCV) index; treatment duration beyond 24 months; and prior exposure to immunosuppressant drugs have been developed. METHODS: A group of neurologists from various MS clinics across Canada met in September 2021 to update the 2015 Canadian practice recommendations for the use of natalizumab in persons with MS (PwMS). RESULTS: The recommendations focused on the long-term efficacy and safety data from real-world studies, patient selection according to JCV index criteria, risk management strategies for PML (including extended interval dosing), and options for switching to currently available disease-modifying therapies for MS. CONCLUSIONS: The recommendations of clinical neurologists seek to optimize the management of PwMS who may benefit from treatment with natalizumab.