The Treatment of Neuromyelitis Optica: Present and Future Perspective

The treatment of neuromyelitis optica (NMO) should be considerably different between the acute phase and chronic phase. In the acute phase, steroid pulse therapy with high-dose methylprednisolone is the first-line therapy to achieve swift remission and to prevent irreversible disabilities. If one or two courses of steroid pulse therapy are insufficient, plasma exchange should be urgently considered. In the chronic phase, long-term immunosuppressive therapies, including low-dose oral corticosteroid therapy, is the mainstay therapy. These preventive therapies may be necessary several years or more and should not be casually interrupted, because the relapse rate without immunosuppressants is quite high in NMO. Azathioprine is one of the most widely used immunosuppressants that can spare the steroid dose when combined with oral corticosteroid, benefitting patients by reducing steroid-induced side effects. Rituximab is a monoclonal antibody that has been widely used as a preventive therapy, while other monoclonal antibodies such as eculizumab and tocilizumab have shown their superior efficacy in recent trials. The treatment of pain is also an important aspect in managing NMO patients. Differing from multiple sclerosis, fingolimod, interferon-beta, and natalizumab should be avoided in NMO, because they could trigger relapse or exacerbate symptoms in some NMO patients. It may be possible to develop preventive therapies for NMO in the future, including AQP4-Ab blocker therapy, and a more precise understanding of the pathomechanisms of NMO may lead to the development of more effective drugs. Furthermore, discovery of useful biomarkers that reflect the disease activity of NMO is definitely required for developing effective drugs for NMO treatment.