This global, long-term, prospective, multicenter, observational registry will enroll adults with AQP4-Ab+ NMOSD treated with C5ITs who received ≥1 dose of eculizumab or ravulizumab ≤4 or ≤12 weeks prior to enrollment, respectively. Inclusion criteria include available historical C5IT dosing data since initiation and relapse data from ≤1 year before C5IT initiation through enrollment. Retrospective outcomes include disease onset and diagnosis. Relapse data, treatment history, vaccinations, and available Expanded Disability Status Scale (EDSS) scores will be collected from 1 year prior to C5IT initiation through enrollment. The primary outcome is annualized relapse rate; effectiveness outcomes include C5IT effects on disability (EDSS score), ambulation (Hauser Ambulation Index), and vision (Best Corrected Visual Acuity). Collected patient-reported outcomes (PROs) include pain, bladder and bowel dysfunction, and quality of life. Utilization of eculizumab and ravulizumab, other therapies for management of AQP4-Ab+ NMOSD, vaccination and antibiotic use related to risk of meningococcal infection, and hospitalizations will be assessed. Safety outcomes include serious adverse events, meningococcal infections, and pregnancy, breastfeeding, and neonatal outcomes. Data will be collected prospectively for ≤5 years; clinical data will be collected at least annually and PRO data every 6 months. Approximately 130–200 patients will be enrolled in ≤10 countries. Descriptive statistics will be used.

This registry will collect data to characterize long-term effectiveness and safety of eculizumab and ravulizumab in patients with AQP4-Ab+ NMOSD and the real-world impact of C5ITs in this population.