Safety of Rituximab as First-line Therapy in Neuromyelitis Optica (NMO) and NMO-spectrum Disorders: Five Years of Experience (P5.264)

OBJECTIVE: We describe our experience with rituximab as first-line treatment in patients with neuromyelitis optica (NMO) and NMO-spectrum disorders (SD). BACKGROUND: NMO is an autoimmune disorder of the central nervous system caused by antibodies against aquaporin-4 water channels. It is characterized by recurrent episodes of optic neuritis and transverse myelitis. The severe neurological impairment and the high risk of disability determine the need for aggressive treatment in both relapse and prophylactic settings. There are no disease-modifying treatments with specific indication, so different immunosuppressants are used based on consensus and clinical experience. Rituximab (RTX), anti-CD20 monoclonal antibody, is considered a therapeutic option. DESIGN/METHODS: Retrospective study of 13 patients with NMO or NMO-SD treated during 5 years with rituximab as first-line treatment. We analyze the effectiveness using the annualized relapse rate (ARR) and describe also clinical and safety outcomes. RESULTS: Of the 13 patients enrolled 38.5[percnt] had NMO and 61.5[percnt] NMO-SD. Mean age: 36.5 years; 76.9[percnt] female. NMO-IgG+: 30.8[percnt]. Time between disease onset and treatment initiation: 2.4 years. The RTX dose was 375 mg/m 2 intravenously, once per week for 4 weeks; we also administered a booster dose according to the levels of CD19 + /CD27 + found in the analytical monitoring every 3 months, with an interval of 6-12 months. Mean EDSS pre-RTX was 4 vs 1.8 post-RTX. Disability improved or stabilized in 10/13 patients. ARR pre-RTX was 1.4 vs 0.2 post-RTX, with a reduction of 85.7[percnt] (p + >0.05[percnt]. Regarding adverse events, one patient had an IgA deficiency and another one a recurrent immune thrombocytopenic purpura with each RTX dose, which lead to treatment switch. CONCLUSIONS: In our experience, first-line treatment of NMO with rituximab is effective by significantly reducing the relapse rate, with an excellent safety profile. Disclosure: Dr. Carreon-Guarnizo has nothing to disclose. Dr. Hernandez Clares has nothing to disclose. Dr. PALAZON has nothing to disclose. Dr. Carrasco-Torres has nothing to disclose. Dr. Salgado has nothing to disclose. Dr. Jimenez Veiga has nothing to disclose. Dr. Leon-Hernandez has nothing to disclose. Dr. Martin-Fernandez has nothing to disclose. Dr. Jose has nothing to disclose.