It has been shown in some scientific studies that the the antibody marker specific for neuromyelitis optica (NMO), known as NMO-Immunoglobulin G (IgG), causes inflammation in brain tissues by activating a substance called complement. Complement can greatly increase the immune attack in the optic nerves (causing optic neuritis (ON)), spinal cords (causing transverse myelitis (TM)) and brains of patients with NMO. Eculizumab has already been shown to be effective in a rare blood disorder known as paroxysmal nocturnal hemoglobinuria (PNH). Attacks of PNH are also mediated through complement. Therefore, the investigators of this study are investigating whether by 'turning off' complement in NMO, further attacks of NMO can be prevented.~The primary (most important) objectives of this study are to determine:~Whether Eculizumab reduces relapse frequency in patients with relapsing NMO. The number of attacks during the one year treatment period will be compared to the number of attacks that occurred prior to initiation of eculizumab treatment. For patients with more than 2 year disease duration, the average number of attacks in the preceding 2 years will be calculated. For patients with less than 2 years disease duration the number of attacks in the preceding year will be used.~The safety profile of eculizumab in patients with NMO.~The secondary objectives are to determine:~Whether eculizumab maintains or improves walking, visual function and quality of life as measured by a variety of established disability scales. We will also assess the severity of an individual attack and the degree of recovery.~How the drug behaves in the patient's blood (called pharmacodynamics and pharmacokinetics).~Depending on our preliminary investigations we may evaluate patient cerebrospinal fluid in the laboratory to see how effective eculizumab is at getting into the cerebrospinal fluid from the blood stream, and to see if the drug reverses the biological effects of the NMO-IgG antibody.
The purpose of this study is to determine if the drug eculizumab reduces the attack rate and improves outcome in patients with neuromyelitis optica.