Efficacy and Safety of Baricitinib in Neuromyelitis Optica Spectrum Disorders

Inclusion Criteria: 1. Male or female patients ≥ 18 years old; 2. Diagnosis of NMO or NMO spectrum disorder according to the 2015 International Panel for Neuromyelitis Optica Diagnosis criteria; 3. Clinical evidence of either at least one attack requiring rescue therapy (intravenous corticosteroids, intravenous immunoglobulin, plasma exchange, or a combination of these therapies) in the year before screening or at least two attacks requiring rescue therapy in the 2 years before screening; 4. EDSS \<=6.0; 5. Patients were seropositive for AQP4-IgG; 6. Able and willing to give written informed consent and comply with the requirements of the study protocol. Exclusion Criteria: 1. Current evidence or known history of clinically significant infection (Herpes simplex virus, varicella-zoster virus, cytomegalovirus, Epstein-Barr virus, human immunodeficiency virus, Hepatitis viruses, Syphilis, etc); 2. Participation in another interventional trial within the last 3 months Tumor disease currently or within last 5 years; 3. Pregnant, breastfeeding, or child-bearing potential during the course of the study Clinically relevant heart, liver, kidney or bone marrow function disorder. 4. Have a history of venous thromboembolism (VTE), or are considered at high risk for VTE by the investigator.