Novel emerging treatments for NMOSD

Neuromyelitis optica spectrum disorders (NMOSD) are inflammatory demyelinating diseases of the central nervous system (CNS) that cause optic neuritis, transverse myelitis, and some other CNS syndromes. Recently, diagnosis and understanding of these diseases has been markedly enhanced by the discovery that serum autoantibodies that target aquaporin-4 (AQP4) are strongly associated with the disease. This spectrum includes also a potential subset of patients with a phenotype of NMOSD who have anti-myelin oligodendrocyte glycoprotein (MOG) antibody. Although steroids and immunosuppressive drugs have been widely used for NMOSD treatment, until recently there was no approved therapy for these diseases. With improved understanding of the pathophysiology of NMOSD, numerous new therapeutic strategies have recently been evaluated. The results of these studies, involving monoclonal antibodies (mAbs) inhibiting terminal complement protein cleavage interfering with interleukin-6 receptor (IL-6 R) signaling and depleting CD19-positive B cells, have been published in recent months. All of these new therapeutics have shown a high degree of efficacy in diminishing NMOSD activity and inhibiting disability progression. At the same time, all these mAbs have demonstrated favorable safety and tolerability profiles, with a limited rate of adverse events. The first of these new drugs, eculizumab, have been approved in USA and Europe for NMOSD treatment within the last couple of months and it is expected that the other novel, effective and safe treatments for NMOSD will be approved in the near future.