Treatment of neuromyelitis optica with rituximab: a 2-year prospective multicenter study.

Abstract

Neuromyelitis optica (NMO) is a very severe autoimmune disorder of the central nervous system. It affects young subjects and has a poor prognosis both on a functional and vital level. Therefore, it is imperative to reduce the frequency of relapses. The purpose of this study was to evaluate the clinical and neuroradiological effectiveness of rituximab (RTX) on active forms of NMO. We conducted a 2-year open prospective multicenter study that included 32 patients treated with RTX at a dose of 375mg/m2/week for 1month. When the number of circulating CD19+ B cells reached 1%, a maintenance therapy was started, consisting of two infusions of 1g of RTX, administered at a 15-day interval. The primary objective was to reduce the annual relapse rate (ARR), in comparison to that observed in the 2years before treatment onset. Rituximab administration reduced the ARR from 1.34 to 0.56 (p=0.0005). The average Expanded Disability Status Scale (EDSS) score significantly improved by 1.1 point, from 5.9 (2-9) to 4.8 (0-9) after 2years (p=0.03). Anti-aquaporin-4 antibodies' level predicted treatment failure (p=0.03). Frequency of Gad+ lesions in spinal cord decreased from 23.3 to 14.2%. RTX treatment did not prevent the death of three patients (treatment failure in two patients and acute myeloid leukemia in a patient previously treated with mitoxantrone). Rituximab is clinically effective in active forms of NMO, although few patients are resistant to the treatment.