Emerging treatments for neuromyelitis optica spectrum disorder

Excerpt

Neuromyelitis optica spectrum disorder (NMO-SD) has a worldwide prevalence of 0.5–10 persons per 100,000 population. It is characterised by inflammatory events centred on the optic nerve and spinal cord, often with poor recovery and subsequent residual disability. More than two-thirds of patients with NMO-SD have serum antibodies to the water channel protein aquaporin-4 (AQP4-immunoglobulin G [IgG]), which is implicated in the pathophysiology of NMO-SD. Others are seronegative or have serum antibodies to myelin oligodendrocyte glycoprotein. Diagnostic criteria depend on AQP4-IgG antibody status: those with seropositivity can have involvement of almost any CNS region, whereas those who are seronegative must have experienced at least one of either an optic neuritis, longitudinally extensive transverse myelitis, or area postrema syndrome with associated MRI lesions. Treatment of NMO-SD to date has largely been based on observational studies, case reports and retrospective analyses, and has included empiric use of off-label treatments such as rituximab, azathioprine and mycophenolate mofetil. However, with the recent completion of phase 3 clinical trials, an improved evidence base for current treatments and novel treatment options for NMO-SD are now emerging. Three clinical trials evaluate the monoclonal antibodies rituximab, satralizumab and eculizumab, versus placebo in the treatment of NMO-SD, and are discussed below. …