Citations

ObjectiveTo compare longitudinally extensive myelitis in neuromyelitis optica spectrum disorders (NMOSD) and spinal cord sarcoidosis (SCS).MethodsWe identified adult patients evaluated between 1996 and 2015 with SCS or NMOSD whose first myelitis episode was accompanied by a spinal cord lesion spanning ≥3 vertebral segments. All NMOSD patients were positive for aquaporin‐4–immunoglobulin G, and all sarcoidosis cases were pathologically confirmed. Clinical characteristics were evaluated. Spine magnetic resonance imaging was reviewed by 2 neuroradiologists.ResultsWe studied 71 patients (NMOSD, 37; SCS, 34). Sixteen (47%) SCS cases were initially diagnosed as NMOSD or idiopathic transverse myelitis. Median delay to diagnosis was longer for SCS than NMOSD (5 vs 1.5 months, p < 0.01). NMOSD myelitis patients were more commonly women, had concurrent or prior optic neuritis or intractable vomiting episodes more frequently, had shorter time to maximum deficit, and had systemic autoimmunity more often than SCS (p < 0.05). SCS patients had constitutional symptoms, cerebrospinal fluid (CSF) pleocytosis, and hilar adenopathy more frequently than NMOSD (p < 0.05); CSF hypoglycorrhachia (11%, p = 0.25) and elevated angiotensin‐converting enzyme (18%, p = 0.30) were exclusive to SCS. Dorsal cord subpial gadolinium enhancement extending ≥2 vertebral segments and persistent enhancement >2 months favored SCS, and ringlike enhancement favored NMOSD (p < 0.05). Maximum disability was similar in both disorders.InterpretationSCS is an under‐recognized cause of longitudinally extensive myelitis that commonly mimics NMOSD. We identified clinical, laboratory, systemic, and radiologic features that, taken together, help discriminate SCS from NMOSD. ANN NEUROL 2016;79:437–447

Background: To date, no treatment for neuromyelitis optica (NMO) has been granted regulatory approval, and no controlled clinical studies have been reported. Objective: To design a placebo-controlled study in NMO that appropriately balances patient safety and clinical–scientific integrity. Methods: We assessed the “standard of care” for NMO to establish the ethical framework for a placebo-controlled trial. We implemented measures that balance the need for scientific robustness while mitigating the risks associated with a placebo-controlled study. The medical or scientific community, patient organizations, and regulatory authorities were engaged early in discussions on this placebo-controlled study, and their input contributed to the final study design. Results: The N-MOmentum study (NCT02200770) is a clinical trial that randomizes NMO patients to receive MEDI-551, a monoclonal antibody that depletes CD19+ B-cells, or placebo. The study design has received regulatory, ethical, clinical, and patient approval in over 100 clinical sites in more than 20 countries worldwide. Conclusion: The approach we took in the design of the N-MOmentum trial might serve as a roadmap for other rare severe diseases when there is no proven therapy and no established clinical development path.

The discovery of AQP4‐IgG (a pathogenic antibody that targets the astrocytic water channel aquaporin‐4), as the first sensitive and specific biomarker for any inflammatory central nervous system demyelinating disease (IDD), has shifted emphasis from the oligodendrocyte and myelin to the astrocyte as a central immunopathogenic player. Neuromyelitis optica (NMO) spectrum disorders (SDs) represent an evolving spectrum of IDDs extending beyond the optic nerves and spinal cord to include the brain (especially in children) and, rarely, muscle. NMOSD typical brain lesions are located in areas that highly express the target antigen, AQP4, including the circumventricular organs (accounting for intractable nausea and vomiting) and the diencephalon (accounting for sleep disorders, endocrinopathies, and syndrome of inappropriate antidiuresis). Magnetic resonance imaging brain abnormalities fulfill Barkoff criteria for multiple sclerosis in up to 10% of patients. As the spectrum broadens, the importance of highly specific assays that detect pathogenic AQP4‐IgG targeting extracellular epitopes of AQP4 cannot be overemphasized. The rapid evolution of our understanding of the immunobiology of AQP4 autoimmunity necessitates continuing revision of NMOSD diagnostic criteria. Here, we describe scientific advances that have occurred since the discovery of NMO‐IgG in 2004 and review novel targeted immunotherapies. We also suggest that NMOSDs should now be considered under the umbrella term autoimmune aquaporin‐4 channelopathy .