Neuromyelitis optica spectrum disorder (NMOSD) is caused by antibodies that target the aquaporin-4 (AQP4) water channel expressed on astrocytes. Specific antibody binding to AQP4 produces complement-dependent cytotoxicity, resulting in inflammation and demyelination. New biologic treatments demonstrate high efficacy and good safety for patients with AQP4-immunoglobulin G-positive NMOSD. They were eculizumab, an anti-complement C5 antibody, satralizumab, an anti-interleukin-6 receptor antibody, and inebilizumab and rituximab, which targets CD19 and CD20, respectively, causing depletion of B-cells. In this review, the pathophysiology of NMOSD, the methodology and results of the recent studies examining monoclonal antibody therapies, and the optimal therapeutic strategy for NMOSD were covered.