Efficacy and Safety Study of Satralizumab (SA237) as Add-on Therapy to Treat Participants With Neuromyelitis Optica (NMO) and NMO Spectrum Disorder (NMOSD)

Inclusion Criteria

• Patients must be diagnosed as having either neuromyelitis optica (NMO) or NMO spectrum disorder (NMOSD), defined as the following:
• NMO as defined by Wingerchuk et al. 2006 criteria (requires all of the following 3 criteria: I. Optic neuritis, II. Acute myelitis, III. At least two of three supportive criteria: Contiguous spinal cord lesion identified on a magnetic resonance imaging (MRI) scan extending over 3 vertebral segments; Brain MRI not meeting diagnostic criteria for multiple sclerosis (MS); NMO-IgG seropositive status)
• NMOSD as defined by either of the following Wingerchuk 2007 criteria with anti-AQP4 antibody (Ab) seropositive status at screening (i. Idiopathic single or recurrent events of longitudinally extensive myelitis [≥3 vertebral segment spinal cord MRI lesion]; ii. Optic neuritis: recurrent or simultaneous bilateral); For patients aged 12 to 17 years, a minimum of 4 patients should be positive for anti-AQP4Ab status at screening
• Clinical evidence of at least 2 documented relapses (including first attack) in the last 2 years prior to screening, at least one of which has occurred in the 12 months prior to screening
• EDSS score from 0 to 6.5 inclusive at screening
• Age 12 to 74 years, inclusive at the time of informed consent
• One of the following baseline treatments must be at stable dose as a monotherapy for 8 weeks prior to baseline: Azathioprine; Mycophenolate mofetil; Oral corticosteroids. For participants aged 12 to 17 years, either of the following baseline treatments for relapse prevention can be allowed: Azathioprine + oral corticosteroids; Mycophenolate mofetil + oral corticosteroids
• Ability and willingness to provide written informed consent and to comply with the requirements of the protocol

For adolescents who may be enrolled after the end of the double-blind period, the inclusion criterion 2 is as follows (other criteria are same): Clinical evidence of at least 2 documented relapses (including first attack) prior to screening.

Exclusion Criteria

Exclusion criteria related to previous or concomitant therapy:

• Any previous treatment with IL-6 inhibitory therapy (e.g. tocilizumab), alemtuzumab, total body irradiation or bone marrow transplantation at any time
• Any previous treatment with anti-CD20, eculizumab, belimumab, interferon, natalizumab, glatiramer acetate, fingolimod, teriflunomide or dimethyl fumarate within 6 months prior to baseline
• Any previous treatment with anti-CD4, cladribine or mitoxantrone within 2 years prior to baseline
• Treatment with any investigational agent within 3 months prior to baseline

Exclusions for general safety:

• Pregnancy or lactation
• For patients of reproductive potential, a positive result from a serum pregnancy test at screening, or not willing to use reliable means of contraception (physical barrier [patient or partner] in conjunction with a spermicidal product, contraceptive pill, patch, injectables, intrauterine device or intrauterine system) during the treatment period and for at least 3 months after the last dose of study drug
• Any surgical procedure (except for minor surgeries) within 4 weeks prior to baseline
• Evidence of other demyelinating disease or progressive multifocal leukoencephalopathy (PML)
• Evidence of serious uncontrolled concomitant diseases that may preclude patient participation, such as: other nervous system disease, cardiovascular disease, hematologic/hematopoiesis disease, respiratory disease, muscular disease, endocrine disease, renal/urologic disease, digestive system disease, congenital or acquired severe immunodeficiency
• Known active infection (excluding fungal infections of nail beds or caries dentium) within 4 weeks prior to baseline
• Evidence of chronic active hepatitis B or C
• History of drug or alcohol abuse within 1 year prior to baseline
• History of diverticulitis that, in the Investigator's opinion, may lead to increased risk of complications such