RT Journal Article SR Electronic T1 Long-term Effectiveness and Safety of Rituximab in Neuromyelitis Optica Spectrum Disorder and MOG Antibody Disease JF Neurology JO Neurology FD Lippincott Williams & Wilkins SP e2504 OP e2516 DO 10.1212/WNL.0000000000201260 VO 99 IS 22 A1 Barreras, Paula A1 Vasileiou, Eleni S. A1 Filippatou, Angeliki G. A1 Fitzgerald, Kathryn C. A1 Levy, Michael A1 Pardo, Carlos A. A1 Newsome, Scott D. A1 Mowry, Ellen M. A1 Calabresi, Peter A. A1 Sotirchos, Elias S. YR 2022 UL http://n.neurology.org/content/99/22/e2504.abstract AB Background and Objectives Rituximab is used widely for relapse prevention in neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein (MOG)-IgG–associated disease (MOGAD); however, data regarding the effectiveness and safety of long-term rituximab use in these conditions are limited. In this study, we sought to evaluate long-term clinical outcomes in patients with aquaporin-4 IgG–seropositive (AQP4-IgG+) NMOSD and MOGAD treated with rituximab.Methods We performed a retrospective chart review of patients with AQP4-IgG+ NMOSD or MOGAD followed at the Johns Hopkins Neuromyelitis Optica Clinic and included patients who had received at least 1 dose of rituximab.Results We identified 111 patients with NMOSD and 23 patients with MOGAD who fulfilled the inclusion criteria. The median duration of rituximab treatment for the patients with NMOSD was 3.7 years (range: 0.5–13.2 years) and for the patients with MOGAD was 2.1 years (range: 0.5–7.0 years). The annualized relapse rate (ARR) decreased after rituximab initiation in both NMOSD (median ARR: pretreatment 1.1, posttreatment 0; p < 0.001) and MOGAD (median ARR: pretreatment 1.9, posttreatment 0.3; p = 0.002). Relapses on rituximab occurred in 31 patients with NMOSD (28%) and 14 patients with MOGAD (61%). The majority of NMOSD treatment failures (37/48 relapses; 77%) occurred either within the initial 6 months after starting rituximab (n = 13 relapses) or in the setting of delayed/missed rituximab doses and/or peripheral B-cell reconstitution (n = 24 relapses), whereas in MOGAD, these circumstances were present in a smaller proportion of treatment failures (19/35 relapses; 54%). The risk of relapse on rituximab was greater for patients with MOGAD compared with patients with NMOSD (hazard ratio: 2.8, 95% CI: 1.5–5.2, p = 0.001). Infections requiring hospitalization occurred in 13% and immunoglobulin G (IgG) hypogammaglobulinemia in 17% of patients. The median rituximab treatment duration before IgG hypogammaglobulinemia onset was 5.4 years (interquartile range: 3.8–7.7 years).Discussion Rituximab treatment is associated with the reduced annualized relapse rate in AQP4-IgG–seropositive NMOSD, especially in the absence of gaps in treatment and/or B-cell reconstitution. In MOGAD, although a reduction in relapses was observed after initiation of rituximab, this association appeared to be less robust than in AQP4-IgG–seropositive NMOSD. Severe infections and hypogammaglobulinemia occurred in a significant proportion of patients, highlighting the need for close monitoring of infectious complications.Classification of Evidence This study provides Class IV evidence that rituximab decreases the annualized relapse rate in AQP4-IgG–seropositive NMOSD and MOGAD.ALC=absolute lymphocyte count; ANC=absolute neutrophil count; AQP4-IgG+=aquaporin-4 IgG seropositive; ARR=annualized relapse rate; EDSS=Expanded Disability Status Scale; ICU=intensive care unit; MOG=myelin oligodendrocyte glycoprotein; Ig=Immunoglobulin; IgG=immunoglobulin G; IVIG=intravenous Ig; MOGAD=myelin oligodendrocyte glycoprotein–IgG–associated disease; NMOSD=neuromyelitis optica spectrum disorder; UTI=urinary tract infection; WBC=white blood cell count