Treatment of neuromyelitis optica/neuromyelitis optica spectrum disorders with methotrexate

Treatment of neuromyelitis optica spectrum disorder: revisiting the complement system and other aspects of pathogenesis

Neuromyelitis optica spectrum disorder (NMOSD) represents a rare neuroimmunological disease causing recurrent attacks and accumulation of permanent disability in affected patients. The discovery of the pathogenic IgG‑1 antibody targeting a water channel expressed in astrocytes, aquaporin 4, constitutes a milestone achievement. Subsequently, multiple pathophysiological aspects of this distinct disease entity have been investigated. Demyelinating lesions and axonal damage ensue from autoantibodies targeting an astroglial epitope. This conundrum has been addressed in the current disease model, where activation of the complement system as well as B cells and interleukin 6 (IL-6) emerged as key contributors. It is the aim of this review to address these factors in light of novel treatment compounds which reflect these pathophysiological concepts in aiming for attack prevention, thus reducing disease burden in patients with NMOSD.

Intruders or protectors - the multifaceted role of B cells in CNS disorders

B lymphocytes are immune cells studied predominantly in the context of peripheral humoral immune responses against pathogens. Evidence has been accumulating in recent years on the diversity of immunomodulatory functions that B cells undertake, with particular relevance for pathologies of the central nervous system (CNS). This review summarizes current knowledge on B cell populations, localization, infiltration mechanisms, and function in the CNS and associated tissues. Acute and chronic neurodegenerative pathologies are examined in order to explore the complex, and sometimes conflicting, effects that B cells can have in each context, with implications for disease progression and treatment outcomes. Additional factors such as aging modulate the proportions and function of B cell subpopulations over time and are also discussed in the context of neuroinflammatory response and disease susceptibility. A better understanding of the multifactorial role of B cell populations in the CNS may ultimately lead to innovative therapeutic strategies for a variety of neurological conditions.

Update on the diagnosis and treatment of neuromyelitis optica spectrum disorders (NMOSD) - revised recommendations of the Neuromyelitis Optica Study Group (NEMOS). Part II: Attack therapy and long-term management

This manuscript presents practical recommendations for managing acute attacks and implementing preventive immunotherapies for neuromyelitis optica spectrum disorders (NMOSD), a rare autoimmune disease that causes severe inflammation in the central nervous system (CNS), primarily affecting the optic nerves, spinal cord, and brainstem. The pillars of NMOSD therapy are attack treatment and attack prevention to minimize the accrual of neurological disability. Aquaporin-4 immunoglobulin G antibodies (AQP4-IgG) are a diagnostic marker of the disease and play a significant role in its pathogenicity. Recent advances in understanding NMOSD have led to the development of new therapies and the completion of randomized controlled trials. Four preventive immunotherapies have now been approved for AQP4-IgG-positive NMOSD in many regions of the world: eculizumab, ravulizumab - most recently-, inebilizumab, and satralizumab. These new drugs may potentially substitute rituximab and classical immunosuppressive therapies, which were as yet the mainstay of treatment for both, AQP4-IgG-positive and -negative NMOSD. Here, the Neuromyelitis Optica Study Group (NEMOS) provides an overview of the current state of knowledge on NMOSD treatments and offers statements and practical recommendations on the therapy management and use of all available immunotherapies for this disease. Unmet needs and AQP4-IgG-negative NMOSD are also discussed. The recommendations were developed using a Delphi-based consensus method among the core author group and at expert discussions at NEMOS meetings.

A Clinical Approach to Existing and Emerging Therapeutics in Neuromyelitis Optica Spectrum Disorder

PURPOSE OF REVIEW

Neuromyelitis optica spectrum disorder (NMOSD) is a rare but highly disabling disease of the central nervous system. Unlike multiple sclerosis, disability in NMOSD occurs secondary to relapses that, not uncommonly, lead to blindness, paralysis, and death. Recently, newer, targeted immunotherapies have been trialed and are now in the treatment arsenal. We have endeavoured to evaluate the current state of NMOSD therapeutics.

RECENT FINDINGS

This review provides a pragmatic evaluation of recent clinical trials and post-marketing data for rituximab, inebilizumab, satralizumab, eculizumab, and ravalizumab, contrasted to older agents. We also review contemporary issues such as treatment in the context of SARS-CoV2 infection and pregnancy. There has been a dramatic shift in NMOSD morbidity and mortality with earlier and improved disease recognition, diagnostic accuracy, and the advent of more effective, targeted therapies. Choosing a maintenance therapy remains nuanced depending on patient factors and accessibility. With over 100 putative agents in trials, disease-free survival is now a realistic goal for NMOSD patients.

Neuromyelitis Optica Spectrum Disorders: Clinical Perspectives, Molecular Mechanisms, and Treatments

Neuromyelitis optica (NMO) is a rare autoimmune inflammatory disorder affecting the central nervous system (CNS), specifically the optic nerve and the spinal cord, with severe clinical manifestations, including optic neuritis (ON) and transverse myelitis. Initially, NMO was wrongly understood as a condition related to multiple sclerosis (MS), due to a few similar clinical and radiological features, until the discovery of the AQP4 antibody (NMO-IgG/AQP4-ab). Various etiological factors, such as genetic-environmental factors, medication, low levels of vitamins, and others, contribute to the initiation of NMO pathogenesis. The autoantibodies against AQP4 target the AQP4 channel at the blood–brain barrier (BBB) of the astrocyte end feet, which leads to high permeability or leakage of the BBB that causes more influx of AQP4-antibodies into the cerebrospinal fluid (CSF) of NMO patients. The binding of AQP4-IgG onto the AQP4 extracellular epitopes initiates astrocyte damage through complement-dependent cytotoxicity (CDC) and antibody-dependent cellular cytotoxicity (ADCC). Thus, a membrane attack complex is formed due to complement cascade activation; the membrane attack complex targets the AQP4 channels in the astrocytes, leading to astrocyte cell damage, demyelination of neurons and oligodendrocytes, and neuroinflammation. The treatment of NMOSD could improve relapse symptoms, restore neurological functions, and alleviate immunosuppression. Corticosteroids, apheresis therapies, immunosuppressive drugs, and B cell inactivating and complement cascade blocking agents have been used to treat NMOSD. This review intends to provide all possible recent studies related to molecular mechanisms, clinical perspectives, and treatment methodologies of the disease, particularly focusing on recent developments in clinical criteria and therapeutic formulations.

Progress in treatment of neuromyelitis optica spectrum disorders (NMOSD): Novel insights into therapeutic possibilities in NMOSD

Neuromyelitis optica spectrum disorder (NMOSD) is a rare autoimmune inflammatory demyelinating disorder of the central nervous system (CNS), which is a severely disabling disorder leading to devastating sequelae or even death. Repeated acute attacks and the presence of aquaporin-4 immunoglobulin G (AQP4-IgG) antibody are the typical characteristics of NMOSD. Recently, the phase III trials of the newly developed biologicals therapies have shown their effectiveness and good tolerance to a certain extent when compared with the traditional therapy with the first- and second-line drugs. However, there is still a lack of large sample, double-blind, randomized, clinical studies to confirm their efficacy, safety, and tolerability. Especially, these drugs have no clear effect on NMOSD patients without AQP4-IgG and refractory patients. Therefore, it is of strong demand to further conduct large sample, double-blind, randomized, clinical trials, and novel therapeutic possibilities in NMOSD are discussed briefly here.

Treatment of Neuromyelitis Optica Spectrum Disorders

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune central nervous system (CNS) inflammatory disorder that can lead to serious disability and mortality. Females are predominantly affected, including those within the reproductive age. Most patients develop relapsing attacks of optic neuritis; longitudinally extensive transverse myelitis; and encephalitis, especially brainstem encephalitis. The majority of NMOSD patients are seropositive for IgG autoantibodies against the water channel protein aquaporin-4 (AQP4-IgG), reflecting underlying aquaporin-4 autoimmunity. Histological findings of the affected CNS tissues of patients from in-vitro and in-vivo studies support that AQP4-IgG is directly pathogenic in NMOSD. It is believed that the binding of AQP4-IgG to CNS aquaporin-4 (abundantly expressed at the endfoot processes of astrocytes) triggers astrocytopathy and neuroinflammation, resulting in acute attacks. These attacks of neuroinflammation can lead to pathologies, including aquaporin-4 loss, astrocytic activation, injury and loss, glutamate excitotoxicity, microglial activation, neuroinflammation, demyelination, and neuronal injury, via both complement-dependent and complement-independent pathophysiological mechanisms. With the increased understanding of these mechanisms underlying this serious autoimmune astrocytopathy, effective treatments for both active attacks and long-term immunosuppression to prevent relapses in NMOSD are increasingly available based on the evidence from retrospective observational data and prospective clinical trials. Knowledge on the indications and potential side effects of these medications are essential for a clear evaluation of the potential benefits and risks to NMOSD patients in a personalized manner. Special issues such as pregnancy and the coexistence of other autoimmune diseases require additional concern and meticulous care. Future directions include the identification of clinically useful biomarkers for the prediction of relapse and monitoring of the therapeutic response, as well as the development of effective medications with minimal side effects, especially opportunistic infections complicated by long-term immunosuppression.

New Therapeutic Landscape in Neuromyelitis Optica

Purpose of review

This review discusses the current treatment trends and emerging therapeutic landscape for patients with neuromyelitis optica spectrum disorder (NMOSD).

Recent findings

Conventional immune suppressive therapies, such as B cell depletion, have been used for long-term treatment. However, the availability of recent FDA-approved and investigational drugs has made therapeutic choices for NMOSD more complex.

Summary

Recent randomized clinical trials have shown that eculizumab, inebilizumab, and satralizumab are efficacious therapies for AQP4 seropositive NMOSD. These therapies may not have the same benefit in patients with seronegative NMOSD, including MOG-associated disease, and further investigation is required in this population. Reliable biomarkers to guide therapy decisions are urgently needed. There is a plethora of promising investigational therapies currently in the pipeline with exciting and novel mechanisms of action.

B Cells and Antibodies as Targets of Therapeutic Intervention in Neuromyelitis Optica Spectrum Disorders

The first description of neuromyelitis optica by Eugène Devic and Fernand Gault dates back to the 19th century, but only the discovery of aquaporin-4 autoantibodies in a major subset of affected patients in 2004 led to a fundamentally revised disease concept: Neuromyelits optica spectrum disorders (NMOSD) are now considered autoantibody-mediated autoimmune diseases, bringing the pivotal pathogenetic role of B cells and plasma cells into focus. Not long ago, there was no approved medication for this deleterious disease and off-label therapies were the only treatment options for affected patients. Within the last years, there has been a tremendous development of novel therapies with diverse treatment strategies: immunosuppression, B cell depletion, complement factor antagonism and interleukin-6 receptor blockage were shown to be effective and promising therapeutic interventions. This has led to the long-expected official approval of eculizumab in 2019 and inebilizumab in 2020. In this article, we review current pathogenetic concepts in NMOSD with a focus on the role of B cells and autoantibodies as major contributors to the propagation of these diseases. Lastly, by highlighting promising experimental and future treatment options, we aim to round up the current state of knowledge on the therapeutic arsenal in NMOSD.

Efficacy for the Annual Relapse Rate after the Immunosuppressive Therapy in Patients Associated with Anti-AQP4 or Anti-MOG Antibody-Positive Optic Neuritis

Purpose

Although oral prednisolone is the first-line treatment for preventing recurrent optic neuritis (ON) after the completion of acute-phase treatment, especially anti-aquaporin 4 (AQP4) antibody-positive ON, and anti-myelin oligodendrocyte glycoprotein (MOG) antibody-positive ON, some patients experience relapses. Immunosuppressants could be effective in reducing the recurrence rate for neuromyelitis optica spectrum disorder and MOG antibody-related diseases, but there have been few studies addressing this issue focusing on the changes in ophthalmic parameters. The objective of the study was to analyze the impact of off-label uses of immunosuppressants to reduce recurrent ON.

Design

Retrospective observational study, clinical case series.

Methods

We reviewed the medical charts of 11 cases (22 eyes) who underwent immunosuppressive therapy in Kobe University Hospital and compared the annualized relapse rate (ARR) before and after immunosuppressive therapy. We also evaluated the dosage of prednisolone, complications of immunosuppressants, and other visual functional ophthalmologic parameters.

Results

Eleven cases in total had AQP4 antibody (9 cases) and/or MOG antibody (3 cases). One case was double positive for these antibodies. Nine patients received azathioprine and two received mycophenolate mofetil as an initial immunosuppressive therapy. The median duration of immunosuppressant treatment was 2.8 years. The median ON ARR before immunosuppressive therapy was 0.33, and this decreased significantly to 0 after the therapy (p = 0.02). The dose of prednisolone was reduced from 17.8 ± 7.1 mg/day before to 5.8 ± 2.2 mg/day after immunosuppressive therapy (p < 0.01). Although two patients presented with mild elevation of liver enzymes and nausea, all patients were able to continue taking the immunosuppressants.

Conclusions

Immunosuppressants can potentially decrease relapses and steroid dosage in patients with anti-AQP4 or MOG antibody-positive ON without severe adverse events and the exacerbation of visual acuities.

Advances in the Treatment of Neuromyelitis Optica Spectrum Disorder

Neuromyelitis optica spectrum disorder (NMOSD) is a rare, relapsing-remitting neuroinflammatory disorder of the central nervous system. Advances in the understanding of NMOSD pathogenesis and identification of the NMO-specific pathogenic anti-AQP4 autoantibody have led to the development of highly effective disease-modifying strategies. Five placebo-controlled, randomized trials for NMOSD have been successfully completed as of 2020. These trials support the efficacy of rituximab and tocilizumab and led to the FDA approval of eculizumab, satralizumab and inebilizumab for NMOSD. Our review provides an update on these evidence-based disease-modifying therapies and discussed the treatment of acute relapses in NMOSD.

Neuromyelitis optica

Neuromyelitis optica (NMO; also known as Devic syndrome) is a clinical syndrome characterized by attacks of acute optic neuritis and transverse myelitis. In most patients, NMO is caused by pathogenetic serum IgG autoantibodies to aquaporin 4 (AQP4), the most abundant water-channel protein in the central nervous system. In a subset of patients negative for AQP4-IgG, pathogenetic serum IgG antibodies to myelin oligodendrocyte glycoprotein, an antigen in the outer myelin sheath of central nervous system neurons, are present. Other causes of NMO (such as paraneoplastic disorders and neurosarcoidosis) are rare. NMO was previously associated with a poor prognosis; however, treatment with steroids and plasma exchange for acute attacks and with immunosuppressants (in particular, B cell-depleting agents) for attack prevention has greatly improved the long-term outcomes. Recently, a number of randomized controlled trials have been completed and the first drugs, all therapeutic monoclonal antibodies, have been approved for the treatment of AQP4-IgG-positive NMO and its formes frustes.

Recent progress in maintenance treatment of neuromyelitis optica spectrum disorder

Background

Treatment of neuromyelitis optica spectrum disorder (NMOSD) has so far been based on retrospective case series. The results of six randomized clinical trials including five different monoclonal antibodies targeting four molecules and three distinct pathophysiological pathways have recently been published.

Methods

Literature search on clinical trials and case studies in NMOSD up to July 10. 2020.

Results

We review mechanism of action, efficacy and side effects, and consequences for reproductive health from traditional immunosuppressants and monoclonal antibodies including rituximab, inebilizumab, eculizumab, tocilizumab and satralizumab.

Conclusion

In NMOSD patients with antibodies against aquaporin 4, monoclonal antibodies that deplete B cells (rituximab and inebilizumab) or interfere with interleukin 6 signaling (tocilizumab and satralizumab) or complement activation (eculizumab) have superior efficacy compared to placebo. Tocilizumab and rituximab were also superior to azathioprine in head-to-head studies. Rituximab, tocilizumab and to some extent eculizumab have well-known safety profiles for other inflammatory diseases, and rituximab and azathioprine may be safe during pregnancy.

Efficacy and safety of rituximab in patients with refractory neuromyelitis optica spectrum disorders: A prospective observation in Iranian cases

Background:

Rituximab has been used successfully in the recent years for treatment of neuromyelitis optica spectrum disorders (NMOSD). However, a uniform treatment protocol for maintenance therapy and the best interval for evaluation and retreatment have not been postulated. We evaluated the efficacy and safety of rituximab treatment as second line therapy, in Iranian patients with refractory NMOSD, based on annualized relapse rate (ARR) and expanded disability status scale (EDSS).

Methods:

In this prospective before-after study, a total of 18 patients were treated with a loading dose of rituximab (375 mg/m² weekly in 4 consecutive weeks). Flow cytometric determination of CD19⁺ B cell in peripheral blood sample was carried every 6 weeks and patients were re-treated based on B cell repopulation with a single dose of 375 mg/m². Wilcoxon signed rank test was used to evaluate the ARR and EDSS before and after treatment. A p-value of <0.05 was considered statistically significant.

Results:

Of the 18 patients, 10 (55.5%) were relapse-free during the period of follow up. The EDSS scores were reduced in nine (50%) patients and stable in the remaining nine (50%). The mean EDSS score before and after treatment were 4.1±0.4 and 3.7±0.3, respectively, which was statistically significant. There was also a statistically significant reduction in median ARR after treatment (1.48 (range 0.47-5) vs. 0 (range 0-2)). Rituximab administration did not have significant adverse effect in 94% of patients.

Conclusion:

Repeated treatment with Rituximab is an effective and well-tolerated treatment in refractory NMOSD.

The latest diagnostic criteria and treatment options for neuromyelitis optica

Neuromyelitis optica, also known as Devic disease, is an autoimmune disorder that affects the spinal cord and optic nerve. This atypical demyelinating syndrome can be difficult to diagnose and responds poorly to treatments that are used for multiple sclerosis, a similar demyelinating disease. This article discusses the epidemiology, pathophysiology, clinical presentation, latest diagnostic criteria, and treatment options for neuromyelitis optica and neuromyelitis spectrum disorders.

Evaluation of efficacy and tolerability of first-line therapies in NMOSD

Objective

To compare the efficacy and the risk of severe infectious events of immunosuppressive agents used early as first-line therapy in patients with neuromyelitis optica spectrum disorder (NMOSD).

Methods

We retrospectively included patients with NMOSD and a seropositive status for aquaporin 4 or myelin oligodendrocyte glycoprotein antibodies beginning first-line immunosuppressants within 3 years after the disease onset. The main outcome was occurrence of relapse after the initiation of immunosuppressants; the secondary outcome was the annual relapse rate (AAR).

Results

A total of 136 patients were included: 62 (45.6%) were treated with rituximab (RTX), 42 (30.9%) with mycophenolate mofetil (MMF), and 23 (16.9%) with azathioprine (AZA). Compared with RTX-treated patients, the risk of relapse was higher among MMF-treated patients (hazard ratio [HR], 2.74 [1.17–6.40]; p = 0.020) after adjusting for age at disease onset, sex, antibody status, disease duration, ARR before treatment, corticosteroid intake, and relapse location. We did not observe any difference between RTX-treated and AZA-treated patients (HR, 2.13 [0.72–6.28]; p = 0.17). No interaction was found between the antibody status and immunosuppressive treatments. ARR was lower with RTX than with MMF (p = 0.039), but no difference was observed with AZA. We observed 9 serious infectious events with MMF, 6 with RTX, and none with AZA.

Conclusions

The use of first-line RTX in NMOSD appears more effective than MMF in suppressing clinical activity, independent of the antibody status.

Classification of evidence

That study provides Class III evidence that for patients with NMOSD, first-line RTX is superior to MMF to reduce the risk of relapse.

Diagnosis and Treatment of NMO Spectrum Disorder and MOG-Encephalomyelitis

Neuromyelitis optica spectrum disorders (NMOSD) are autoantibody mediated chronic inflammatory diseases. Serum antibodies (Abs) against the aquaporin-4 water channel lead to recurrent attacks of optic neuritis, myelitis and/or brainstem syndromes. In some patients with symptoms of NMOSD, no AQP4-Abs but Abs against myelin-oligodendrocyte-glycoprotein (MOG) are detectable. These clinical syndromes are now frequently referred to as "MOG-encephalomyelitis" (MOG-EM). Here we give an overview on current recommendations concerning diagnosis of NMOSD and MOG-EM. These include antibody and further laboratory testing, MR imaging and optical coherence tomography. We discuss therapeutic options of acute attacks as well as longterm immunosuppressive treatment, including azathioprine, rituximab, and immunoglobulins.

Clinical Characteristics of Anti-aquaporin 4 Antibody Positive Optic Neuritis in Japan

To investigate the clinical characteristics and the effectiveness of maintenance therapy of anti-AQP4 antibody positive optic neuritis in Japanese patients, medical records from 69 patients (103 eyes) were retrospective reviewed. The status of relapse in patients who received maintenance therapy following acute therapy was compared with that before maintenance therapy in patients who started maintenance therapy ≥6 months after acute therapy. In Japan, anti-AQP4 antibody positive optic neuritis was characterized by older onset age and poor visual outcome. The yearly rate and total number of relapses were lower when maintenance therapy was followed immediately after acute therapy.

Neuromyelitis Optica (Devic's Syndrome): an Appraisal

Neuromyelitis optica (NMO) and neuromyelitis optica spectrum disorders (NMOSD), previously known as Devic's syndrome, are a group of inflammatory disorders of the central nervous system (CNS) characterized by severe, immune-mediated demyelination and axonal damage, predominantly targeting optic nerves and the spinal cord typically associated with a disease-specific serum NMO-IgG antibody that selectively binds aquaporin-4 (AQP4). The classic and best-defined features of NMOSD include acute attacks of bilateral or rapidly sequential optic neuritis (leading to visual loss) or transverse myelitis (often causing limb weakness and bladder dysfunction) or both with a typically relapsing course. The diagnosis of NMO/NMOSD requires a consistent history and examination with typical clinical presentations, findings on spinal cord neuroimaging with MRI, cerebrospinal fluid analysis along with determination of AQP4-IgG serum autoantibody status, and exclusion of other disorders. Two major advances in this field has been the development of diagnostic criteria and treatment recommendations. Consensus diagnostic criteria have been established and were recently revised and published in 2015, enhancing the ability to make a diagnosis and appropriately evaluate these disorders. Expert recommendations and uncontrolled trials form the basis of treatment guidelines. All patients with suspected NMOSD should be treated for acute attacks as soon as possible with high-dose intravenous methylprednisolone -1 gram daily for three to five consecutive days and in some cases, plasma exchange should be used. It is recommended that every patient with NMOSD be started on an immunosuppressive agent, such as, azathioprine, methotrexate, or mycophenolate and in some cases, rituximab, soon after the acute attack and usually be treated for about 5 years after the attack. These advances have helped improve the prognosis and outcome in these disorders.

Rituximab in the treatment of Neuromyelitis optica: a multicentre Italian observational study

Rituximab (RTX) efficacy in NMO is suggested by several case series. No consensus exists on optimal dosing strategies. At present the treatment schedules more frequently used are 375 mg/m2/week iv for 4 weeks (RTX-A) and 1000 mg iv twice, 2 weeks apart (RTX-B). Aim of this study is to confirm RTX efficacy and safety in the treatment of NMO and to evaluate whether a most favourable dosage regimen exists. Data on RTX-treated NMO patients were collected from 13 Italian Hospitals. 73 patients (64 F), were enlisted. RTX-A was administered in 42/73 patients, RTX-B in 31/73. Median follow-up was 27 months (range 7-106). Mean relapse rate in the previous year before RTX start was 2.2 ± 1.3 for RTX-A and 2.3 ± 1.2 for RTX-B. ARR in the first year of treatment was 0.8 ± 0.9 for RTX-A and 0.2 ± 0.4 for RTX-B, in the second year of treatment was 0.9 ± 1.5 for RTX-A and 0.4 ± 0.8 for RTX-B patients (p = 0.001 for the first year, ns (0.09) for the second year). RTX-B was more effective in delaying the occurrence of a relapse (HR 2.2 (95 % IC 1.08-4.53) p = 0.02). Adverse events were described in 19/73 patients (mainly urinary tract and respiratory infections, and infusion reactions). Two deaths were reported in severely disabled patients. Though with the limitations of an observational study, our data support RTX efficacy in NMO and suggest that high dose pulses might be more effective than a more fractioned dose.

Present and Future Therapies in Neuromyelitis Optica Spectrum Disorders

Neuromyelitis optica spectrum disorders (NMOSD) are important evolving entities, which have reached much attention in the recent years. NMOSD are characterized by inflammatory lesions in the optic nerves, spinal cord, and central parts of the brain, as well as an autoimmune process directed against aquaporin-4. As disability in NMOSD accumulates by inflammatory damage from attacks, both the treatment and prevention of attacks are decisive for the long-term outcome. NMOSD attacks are treated with high-dose intravenous corticosteroids and apheresis therapies, in particular therapeutic plasma exchange. In cases of incomplete remission, escalation of attack treatment is recommended. Preventive therapy is immunosuppressive and should by commenced as early as possible. Apart from classical immunosuppressants such as azathioprine and mycophenolate mofetil, repurposed biologicals are increasingly used. B-cell depletion with rituximab and other agents, inhibition of the interleukin-6 receptor with tocilizumab, and blockade of complement-mediated damage by eculizumab all are promising therapeutic strategies evaluated in randomized controlled trials. In this review, we will discuss present and future immunotherapies for NMOSD and also consider combination of treatments, plasma, cellular and other therapies. Current advances in immunopathological knowledge are translated into innovative concepts and begin a new era of NMOSD therapy.

Treatment of Neuromyelitis Optica Spectrum Disorder: Acute, Preventive, and Symptomatic

OPINION STATEMENT

Neuromyelitis optica spectrum disorder (NMOSD) is a rare, autoimmune disease of the central nervous system that primarily attacks the optic nerves and spinal cord leading to blindness and paralysis. The spectrum of the disease has expanded based on the specificity of the autoimmune response to the aquaporin-4 water channel on astrocytes. With wider recognition of NMOSD, a standard of care for treatment of this condition has condition based on a growing series of retrospective and prospective studies. This review covers the present state of the field in the treatment of acute relapses, preventive approaches, and therapies for symptoms of NMOSD.

Therapy of NMO spectrum disorders

Neuromyelitis optica (NMO) is an autoimmune demyelinating condition of the central nervous system often associated with aquaporin-4 (AQP4) autoantibodies manifesting as severe optic neuritis and long segment myelitis with tendency to relapse. Seronegative patients and who do not meet the NMO criteria are classified as having NMO Spectrum Disorder (NMOSD), but are treated identically to clinically definite NMO. Acute relapse is treated with intravenous methylprednisolone for 5 days with or without subsequent treatment with plasma exchange (PE). This must be followed by oral steroid to prevent rebound worsening and further relapse. For relapse prevention, immunosuppressive agents that have been found to be effective are azathioprine, rituximab, mycophenolate mofetil, methotrexate, and mitoxantrone; although none of which have been validated in randomized, controlled trial. Some patients do relapse with monotherapy, and switching to more effective agent or use of combination therapy is beneficial in such situation. There is no consensus about the duration of preventive therapy, but generally 2-3 years of relapse-free period is considered the minimum, taking into account the risks of long-term toxicity of these agents.

Acute and Chronic Management of Neuromyelitis Optica Spectrum Disorder

Neuromyelitis optica and neuromyelitis optica spectrum disorder (NMO/NMOSD) is a rare but clinically aggressive demyelinating disease of the central nervous system (CNS) caused by antibodies against water channel protein aquaporin 4 (AQP4) in the astrocytic foot processes. Patients typically present with optic neuritis (ON) or longitudinally extensive transverse myelitis (LETM). The majority of patients with NMOSD show good response to treatment with steroids and plasmapheresis in the acute setting; however, 90 % of patients will eventually have clinical relapses and accrue permanent disability. Currently, immune modulation is the mainstay of maintenance therapy with anti CD-20 (rituximab, Rituxan™) having collectively the strongest evidence to support its use and mycophenolate mofetil having comparable reductions in absolute relapse rate (ARR) and expanded disability status scale (EDSS) scores. Azathioprine, mitoxantrone, and methotrexate also have retrospective case series data that demonstrate reduction in ARR and stabilization of EDSS but with higher relapse rates and exposure to greater risk of treatment toxicities. Excitingly, multiple novel therapies are under clinical study for patients who are refractory to these first-line therapies including monoclonal antibodies targeting interleukin-6 (IL-6), CD19, CD20, complement, and neutrophil elastase inhibitors which may provide additional options for patients with severe clinical presentations. Importantly, no randomized clinical trials have been published to date comparing clinical outcomes of different maintenance therapies in NMOSD. Several trials are currently underway, and results will help guide future management decisions as current evidence is from many small, retrospective case series and cohort studies with many potential confounds.

Neuro-Ophthalmology Annual Review

PURPOSE

The purpose of this review was to update the practicing ophthalmologist on the English language neuro-ophthalmology literature from the past year.

DESIGN

A review of English language literature from August 1, 2013, to August 1, 2014, was conducted.

METHODS

The author searched PubMed from August 1, 2013, to August 1, 2014, limited to English language publications including original articles, review articles, and case reports and excluding letters to the editor, unpublished work, and abstracts. The following topics were searched: pupillary abnormalities, eye movement dysfunction, neuromuscular diseases, optic neuropathies, optic neuritis, demyelinating diseases including multiple sclerosis, lesions of the optic chiasm and posterior primary visual pathways, elevated intracranial pressure, tumors and aneurysms affecting the visual pathways, vascular diseases, higher visual function, and neuroimaging advances. The focus of this review is on clinically relevant literature in the past year for the practicing ophthalmologist. The aim was to highlight remarkable and interesting literature rather than exhaustively including all new neuro-ophthalmological publications of the year.

RESULTS

Initially, more than 11,000 articles were identified. One hundred were selected that met criteria specified above.

CONCLUSIONS

This review updates the comprehensive ophthalmologist on neuro-ophthalmic topics.

Comparative analysis of treatment outcomes in patients with neuromyelitis optica spectrum disorder using multifaceted endpoints

BACKGROUND

There is still an unmet need for comparative analyses of available treatment options for neuromyelitis optica spectrum disorder (NMOSD).

OBJECTIVE

We aimed to compare the efficacies of the immunosuppressants most commonly prescribed for patients with NMOSD using multifaceted endpoints.

METHODS

We conducted a retrospective analysis of treatment outcomes in 138 NMOSD patients treated with azathioprine, mycophenolate mofetil (MMF), or rituximab. The primary outcome measures were the annualized relapse rate (ARR), annualized severe relapse rate, time to first relapse, and time to first severe relapse.

RESULTS

A comparison of any relapse among the groups revealed that the azathioprine had a significantly higher risk of relapse relative to the rituximab (hazard ratio: 1.82; 95% CI: 1.1-3.1; p=0.03). A comparison of severe relapse among the groups revealed that the hazard ratios of severe relapse for the azathioprine and MMF relative to the rituximab were 11.66 (95% CI: 2.6-52.3; p=0.001) and 5.96 (95% CI: 1.0-35.1; p=0.048), respectively. The times to first relapse and first severe relapse were also significantly different among the treatment groups

CONCLUSIONS

The present study showed that reductions in the risks of relapse and severe relapse differed among patients who were initially treated with azathioprine, MMF, and rituximab.

Epidemiological, clinical, and immunological characteristics of neuromyelitis optica: A review

The aim of this study was to review the epidemiological and clinical characteristics of neuromyelitis optica (NMO) and the immunopathological mechanisms involved in the neuronal damage. NMO is an inflammatory demyelinating autoimmune disease of the central nervous system that most commonly affects the optic nerves and spinal cord. NMO is thought to be more prevalent among non-Caucasians and where multiple sclerosis (MS) prevalence is low. NMO follows a relapsing course in more than 80-90% of cases, which is more commonly in women. It is a complex disease with an interaction between host genetic and environmental factors and the main immunological feature is the presence of anti-aquaporin 4 (AQP4) antibodies in a subset of patients. NMO is frequently associated with multiple other autoantibodies and there is a strong association between NMO with other systemic autoimmune diseases. AQP4-IgG can cause antibody-dependent cellular cytotoxicity (ADCC) when effector cells are present and complement-dependent cytotoxicity (CDC) when complement is present. Acute therapies, including corticosteroids and plasma exchange, are designed to minimize injury and accelerate recovery. Several aspects of NMO pathogenesis remain unclear. More advances in the understanding of NMO disease mechanisms are needed in order to identify more specific biomarkers to NMO diagnosis.