Registry of Patients With AQP4+ NMOSD Treated With Alexion C5 Inhibitor Therapies

Inclusion Criteria:

• Participant is ≥ 18 years of age at the time of enrollment in the Registry.

• Participant must have a confirmed diagnosis of AQP4+ NMOSD.

• At the time of enrollment in the Registry, participants must be receiving treatmentwith ALXN-C5IT for the purpose of chronic relapse prevention in a manner consistentwith the local label. Specifically, they should have received at least 1 dose ofeculizumab within 4 weeks prior to enrollment or at least 1 dose of ravulizumabwithin 12 weeks prior to enrollment.

• Participants must have both the following historical data available to be enrolledin the Registry: ALXN-C5IT dosing information since initiation and number and typesof relapses from 1 year prior to ALXN-C5IT initiation through Registry enrollment.

Exclusion Criteria:

• Participants currently enrolled in an interventional clinical study for thetreatment of AQP4+ NMOSD in which the intervention is a drug.