A 5-Year Follow-up of Rituximab Treatment in Patients With Neuromyelitis Optica Spectrum Disorder

Abstract

A previous 2-year analysis of repeated rituximab treatment in patients with neuromyelitis optica (NMO) revealed significant improvements in relapse rates and disability. We report the findings from the longest follow-up of rituximab treatment in NMO, which provide reassurance regarding the long-term efficacy and safety of rituximab in NMO. To report the results of rituximab treatment in patients with relapsing NMO or NMO spectrum disorder (NMOSD) for a median of 60 months. Retrospective case series in an institutional referral center for multiple sclerosis, including 30 patients with relapsing NMO or NMOSD. After induction therapy, a single infusion of rituximab (375 mg/m2) as maintenance therapy was administered whenever the frequency of reemerging CD27+ memory B cells in peripheral blood mononuclear cells, as measured with flow cytometry, exceeded 0.05%in the first 2 years and 0.1% thereafter. Annualized relapse rate (ARR), disability (Expanded Disability Status Scale score), change in anti–aquaporin 4 antibody, and safety of rituximab treatment. Of 30 patients, 26 (87%) exhibited a marked reduction in ARR over 5 years (mean [SD] pretreatment vs posttreatment ARR, 2.4 [1.5] vs 0.3 [1.0]). Eighteen patients (60%) became relapse free after rituximab treatment. In 28 patients (93%), the disability was either improved or stabilized after rituximab treatment. No serious adverse events leading to discontinuation were observed during follow-up. Repeated treatment with rituximab in patients with NMOSD over a 5-period, using an individualized dosing schedule according to the frequency of reemerging CD27+ memory B cells, leads to a sustained clinical response with no new adverse events.