Failure of Natalizumab to Prevent Relapses in Neuromyelitis Optica

Abstract

Neuromyelitis optica (NMO) is a disabling autoimmune central nervous system (CNS) disorder with clinical attacks mainly involving the optic nerves and the spinal cord.^1,2 The detection of a serum antibody to the CNS water channel aquaporin 4 (AQP4) as a highly specific biomarker in most patients with NMO^3-5 has facilitated its distinction from multiple sclerosis (MS), which may be difficult solely on the basis of clinical and neuroradiological findings. Thus, it is conceivable that a substantial number of patients with NMO have been misdiagnosed with MS, in particular prior to the availability of AQP4 antibody testing. While first-line therapy for MS comprises disease-modifying drugs such as interferon beta and glatiramer acetate, NMO usually requires aggressive immunosuppression or a specific B-cell–targeted therapy.^6-10 Treatment options that are beneficial in MS, especially interferon beta, are of no proven efficacy or may even be harmful in NMO.^11-16