Neuromyelitis Spectrum Disorders Weinshenker, Brian G; Wingerchuk, Dean M
Mayo Clinic proceedings,
04/2017, Letnik:
92, Številka:
4
Journal Article
Recenzirano
Odprti dostop
The understanding of neuromyelitis optica spectrum disorder (NMOSD) has evolved substantially since its initial description over a century ago. The discovery in 2004 of a pathogenic autoantibody ...biomarker targeting aquaporin 4 IgG revolutionized diagnosis and therapeutic development. Although NMOSD resembles multiple sclerosis (MS), differences were identified and articulated in the late 1990s. New diagnostic criteria incorporating the biomarker as well as better understanding of the clinical and radiologic features of NMOSD now permit accurate diagnosis and differentiation from MS. Aquaporin 4 IgG-associated NMOSD is now regarded as an immune astrocytopathy with lytic and nonlytic effects on astrocytes. A second autoantibody, myelin oligodendrocyte glycoprotein IgG, which targets myelin rather than astrocytes, leads to an NMOSD syndrome with clinical and radiologic features that overlap but are distinct from those of aquaporin 4 IgG-associated NMOSD and MS. We review current understanding of the clinical aspects, pathophysiology, and treatment of NMOSD.
Neuromyelitis optica spectrum disorder (NMOSD) is a rare inflammatory CNS disease that primarily manifests as relapsing episodes of severe optic neuritis and myelitis. Diagnosis of NMOSD is supported ...by the detection of IgG autoantibodies that target the aquaporin 4 (AQP4) water channel, which, in the CNS, is an astrocyte-specific protein. AQP4 antibody binding leads to AQP4 internalization, complement-dependent and antibody-dependent cellular cytotoxicity, and water channel dysfunction. Cumulative attack-related injury causes disability in NMOSD, so the prevention of attacks is expected to prevent disability accrual. Until recently, no regulator-approved therapies were available for NMOSD. Traditional immunosuppressant therapies, including mycophenolate mofetil, azathioprine and rituximab, were widely used but their benefits have not been assessed in controlled studies. In 2019 and 2020, five phase II and III randomized placebo-controlled trials of four mechanism-based therapies for NMOSD were published and demonstrated that all four effectively prolonged the time to first relapse. All four drugs were monoclonal antibodies: the complement C5 antibody eculizumab, the IL-6 receptor antibody satralizumab, the B cell-depleting antibody inebilizumab, which targets CD19, and rituximab, which targets CD20. We review the pathophysiology of NMOSD, the rationale for the development of these mechanism-based drugs, the methodology and outcomes of the five trials, and the implications of these findings for the treatment of NMOSD.
Satralizumab, a humanised monoclonal antibody targeting the interleukin-6 receptor, reduced the risk of relapse in patients with neuromyelitis optica spectrum disorder (NMOSD) when added to ...immunosuppressant therapy. This study assessed the safety and efficacy of satralizumab monotherapy in patients with the disorder.
In this phase 3, double-blind, placebo-controlled, parallel-group trial, we enrolled adults aged 18–74 years with aquaporin-4 antibody seropositive or seronegative NMOSD at 44 investigational sites in 13 countries. Eligible participants had experienced at least one documented NMOSD attack or relapse in the past 12 months and had a score of 6·5 or less on the Expanded Disability Status Scale. Exclusion criteria included clinical relapse 30 days or fewer before baseline. Participants were randomly assigned (2:1) to receive satralizumab 120 mg or visually matched placebo subcutaneously at weeks 0, 2, 4, and every 4 weeks thereafter. Taking immunosuppressants concomitantly was prohibited. The primary endpoint was time to the first protocol-defined relapse, based on the intention-to-treat population and analysed with stratification for two randomisation factors (previous therapy for prevention of attacks and nature of the most recent attack). Safety was assessed in all participants who received at least one dose of satralizumab or placebo. The double-blind phase was due to last until 44 protocol-defined relapses occurred or 1·5 years after random assignment of the last patient enrolled, whichever occurred first; participants could enter an open-label phase after the occurrence of a protocol-defined relapse or at the end of the double-blind phase. The study is registered with ClinicalTrials.gov, NCT02073279.
95 (57%) of 168 screened participants were randomly assigned to treatment (63 to satralizumab; 32 to placebo) between Aug 5, 2014, and April 2, 2017. Protocol-defined relapses occurred in 19 (30%) patients receiving satralizumab and 16 (50%) receiving placebo (hazard ratio 0·45, 95% CI 0·23–0·89; p=0·018). 473·9 adverse events per 100 patient-years occurred in the satralizumab group, as did 495·2 per 100 patient-years in the placebo group; the incidence of serious adverse events and adverse events leading to withdrawal was similar between groups.
Satralizumab monotherapy reduced the rate of NMOSD relapse compared with placebo in the overall trial population, with a favourable safety profile. The patient population included a ratio of aquaporin-4 antibody seropositive and seronegative patients that was reflective of clinical practice. Satralizumab has the potential to become a valuable treatment option for patients with NMOSD.
Chugai Pharmaceutical (Roche).
Multiple sclerosis (MS) is a common, disabling, putatively autoimmune neurological disease with worldwide distribution. It typically begins as a relapsing disorder that later evolves to a secondary ...progressive phase. Inflammatory and neurodegenerative mechanisms seem to operate in both phases, but their relative contributions and interactions are incompletely understood. Disease modifying therapies (DMTs) approved for relapsing multiple sclerosis interfere with a variety of immunological mechanisms to reduce rates of relapse, accumulation of disease burden measured by magnetic resonance imaging (MRI), and decline in neurological function over the two to three year duration of typical randomized controlled trials. Benefits of longer duration of therapy on disability are less clear, as data beyond three years are largely limited to observational studies. However, current DMTs do not slow accrual of disability once progressive multiple sclerosis is established. This review summarizes the evidence about the use of approved DMTs and examines how to individualize treatment despite the absence of validated biomarkers to guide drug selection. Methods such as stratifying patients on the basis of estimated risk for future disability, weighing patient specific factors and preferences, and using objective outcomes to adjudicate treatment success are discussed. Emerging drug therapies and strategies are also reviewed.
MRI has improved the diagnostic work-up of multiple sclerosis, but inappropriate image interpretation and application of MRI diagnostic criteria contribute to misdiagnosis. Some diseases, now ...recognized as conditions distinct from multiple sclerosis, may satisfy the MRI criteria for multiple sclerosis (e.g. neuromyelitis optica spectrum disorders, Susac syndrome), thus making the diagnosis of multiple sclerosis more challenging, especially if biomarker testing (such as serum anti-AQP4 antibodies) is not informative. Improvements in MRI technology contribute and promise to better define the typical features of multiple sclerosis lesions (e.g. juxtacortical and periventricular location, cortical involvement). Greater understanding of some key aspects of multiple sclerosis pathobiology has allowed the identification of characteristics more specific to multiple sclerosis (e.g. central vein sign, subpial demyelination and lesional rims), which are not included in the current multiple sclerosis diagnostic criteria. In this review, we provide the clinicians and researchers with a practical guide to enhance the proper recognition of multiple sclerosis lesions, including a thorough definition and illustration of typical MRI features, as well as a discussion of red flags suggestive of alternative diagnoses. We also discuss the possible place of emerging qualitative features of lesions which may become important in the near future.
Objective
A novel autoimmune central nervous system (CNS) disorder with glial fibrillary acidic protein (GFAP)‐IgG as biomarker was recently characterized. Here, 102 patients with GFAP‐IgG positivity ...are described.
Methods
The 102 included patients had: (1) serum, cerebrospinal fluid (CSF), or both that yielded a characteristic astrocytic pattern of mouse tissue immunostaining; (2) confirmation of IgG reactive with specific GFAP isoforms (α, ɛ, or κ) by cell‐based assays; and (3) clinical data available. Control specimens (n = 865) were evaluated by tissue (n = 542) and cell‐based (n = 323) assays.
Results
Median symptom onset age was 44 years (range = 8–103), and 54% were women. The predominant phenotype (83 patients; 81%) was inflammation of meninges, brain, spinal cord, or all 3 (meningoencephalomyelitis). Among patients, highest specificity for those phenotypes was observed for CSF testing (94%), and highest sensitivity was for the GFAPα isoform (100%). Rare GFAP‐IgG positivity was encountered in serum controls by tissue‐based assay (0.5%) or cell‐based assay (1.5%), and in CSF controls by cell‐based assay (0.9%). Among patients, striking perivascular radial enhancement was found on brain magnetic resonance imaging in 53%. Although cases frequently mimicked vasculitis, angiography was uniformly negative, and spinal imaging frequently demonstrated longitudinally extensive myelitic lesions. Diverse neoplasms encountered were found prospectively in 22%. Ovarian teratoma was most common and was predicted best when both N‐methyl‐D‐aspartate receptor–IgG and aquaporin‐4–IgG coexisted (71%). Six patients with prolonged follow‐up had brisk corticosteroid response, but required additional immunosuppression to overcome steroid dependency.
Interpretation
GFAPα‐IgG, when detected in CSF, is highly specific for an immunotherapy‐responsive autoimmune CNS disorder, sometimes with paraneoplastic cause. Ann Neurol 2017;81:298–309
The differential diagnosis of acute inflammatory transverse myelitis (ATM) is broad. Therefore, physicians must be aware of the many potential etiologies for acute myelopathy, and should pursue an ...ordered, efficient, and cost-effective approach to the diagnosis based on the patient's clinical history, examination, and magnetic resonance imaging (MRI) findings. Clinical, immunological, and radiological findings of non-compressive myelopathies are reviewed, as are how these findings can be used to distinguish between demyelinating, infectious, other inflammatory, vascular, neoplastic, and paraneoplastic etiologies. We also review predictors of further episodes of ATM in patients with demyelinating disorders. We discuss the diagnostic clues and pitfalls of the not uncommon clinical scenario of a presumed "myelopathy with normal MRI." Finally, we suggest an algorithm for the diagnosis and management of acute myelopathies.
Summary Atypical inflammatory demyelinating syndromes are rare disorders that differ from multiple sclerosis owing to unusual clinical or MRI findings or poor response to treatments used for multiple ...sclerosis. These syndromes include neuromyelitis optica spectrum disorder, acute disseminated encephalomyelitis, tumefactive demyelination, Baló's concentric sclerosis, Schilder's disease, and Marburg's multiple sclerosis. The overlapping features of these syndromes with multiple sclerosis and with each other complicate diagnosis and their categorisation as distinct or related conditions. Recognition of these syndromes is crucial because they differ from multiple sclerosis and other demyelinating and non-demyelinating conditions in their prognosis and treatment. Advances in MRI, pathology, and immunobiology are needed to increase understanding of these syndromes, including the extent to which some of them represent distinct entities, and to assist with improvements in their diagnosis and management.
Neuromyelitis optica (NMO) is an inflammatory CNS syndrome distinct from multiple sclerosis (MS) that is associated with serum aquaporin-4 immunoglobulin G antibodies (AQP4-IgG). Prior NMO diagnostic ...criteria required optic nerve and spinal cord involvement but more restricted or more extensive CNS involvement may occur. The International Panel for NMO Diagnosis (IPND) was convened to develop revised diagnostic criteria using systematic literature reviews and electronic surveys to facilitate consensus. The new nomenclature defines the unifying term NMO spectrum disorders (NMOSD), which is stratified further by serologic testing (NMOSD with or without AQP4-IgG). The core clinical characteristics required for patients with NMOSD with AQP4-IgG include clinical syndromes or MRI findings related to optic nerve, spinal cord, area postrema, other brainstem, diencephalic, or cerebral presentations. More stringent clinical criteria, with additional neuroimaging findings, are required for diagnosis of NMOSD without AQP4-IgG or when serologic testing is unavailable. The IPND also proposed validation strategies and achieved consensus on pediatric NMOSD diagnosis and the concepts of monophasic NMOSD and opticospinal MS.
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