The investigators primarily aim to observe the time to first relapse from initiation of baricitinib treatment.~The secondary outcomes are to determine: The safety profile of baricitinib in participants with NMO and whether baricitinib improves Expanded Disability Status Scale (EDSS), et al.
Neuromyelitis Optica Spectrum Disorders (NMOSD) is associated with a pathological humoral immune response against the aquaporin-4(AQP-4) water channel. Baricitinib is an oral Janus kinase (JAK)1/JAK2 inhibitor that blocks the upregulated JAK-STAT pathway in patients with neuroimmune disorders, which is important in bone marrow regulation of B cell proliferation and differentiation. Baricitinib may benefit some patients with NMOSD due to the important role of B cells in the pathogenesis of NMOSD. Clincial trials may be needed to observe its efficacy and safety.