A Phase III, Multicenter, Open-Label, Uncontrolled Study to Evaluate Pharmacokinetics, Efficacy, Safety, Tolerability, and Pharmacodynamics of Satralizumab in Pediatric Patients With AQP4 Antibody Positive Neuromyelitis Optica Spectrum Disorder (NMOSD)

Inclusion Criteria: * Age at screening 2-11 years, inclusive * Body weight at screening \>=10 kg * For female patients of childbearing potential (postmenarchal): agreement to either remain completely abstinent (refrain from heterosexual intercourse) or to use a reliable means of contraception * Diagnosed as having NMOSD with AQP4 antibody seropositive status as defined by the Wingerchuk 2015 criteria Clinical evidence of at least one documented attack (including first attack) in the last year prior to screening: * Documented history of a positive anti-AQP4 antibody test or a positive anti-…