New Therapeutic Landscape in Neuromyelitis Optica

Preferences for neuromyelitis optica spectrum disorder treatments: A conjoint analysis with neurologists in Spain

BACKGROUND

The treatment landscape for neuromyelitis optica spectrum disorder (NMOSD) has changed in recent years with the approval of therapies with different efficacy, safety and administration profiles.

OBJECTIVE

The aim of this study was to assess neurologists' preferences for different NMOSD treatment attributes using conjoint analysis (CA).

METHODS

We conducted an online, non-interventional, cross-sectional study in collaboration with the Spanish Society of Neurology. Our CA assessed five drugs' attributes: prevention of relapse, prevention of disability accumulation, safety risk, management during pregnancy, and route and frequency of administration. Participants were presented with eight hypothetical treatment scenarios to rank based on their preferences from the most preferred to the least. An ordinary least squares method was selected to estimate weighted preferences.

RESULTS

A total of 104 neurologists were included. Mean age (standard deviation-SD) was 37.7 (10.3) years, 52.9 % were male, and median time (interquartile range) of experience managing NMOSD was 5.0 (2.9, 10.8) years. Neurologists placed the greatest importance on efficacy attributes, time to relapse (44.1 %) being the most important, followed by preventing disability accumulation (36.8 %). In contrast, route and frequency of administration (4.6 %) was the least important characteristic. Participants who prioritised efficacy attributes felt more comfortable in decision-making, had fewer past experiences of care-related regret and a lower attitude to risk taking than their counterparts.

CONCLUSION

Neurologists' treatment preferences in NMOSD were mainly driven by efficacy attributes. These results may be useful to design policy decisions and treatment guidelines for this condition.

Safety and efficacy of inebilizumab for the treatment of neuromyelitis optica spectrum disorder: end-of-study results from the open-label period of the N-MOmentum trial

BACKGROUND

Inebilizumab, an anti-CD19 B-cell-depleting antibody, demonstrated safety and efficacy in neuromyelitis optica spectrum disorder in the randomised controlled period of the N-MOmentum trial. Here, end-of-study data, including the randomised controlled period and open-label extension period, are reported.

METHODS

In the double-blind, randomised, placebo-controlled, phase 2/3 N-MOmentum trial, adults aged 18 years and older with an neuromyelitis optica spectrum disorder diagnosis, Expanded Disability Status Scale score of 8·0 or less, and history of either at least one acute inflammatory attack requiring rescue therapy in the past year or two attacks requiring rescue therapy in the past 2 years, were recruited from 81 outpatient specialty clinics or hospitals in 24 countries. Eligible participants were randomly assigned (3:1), using a central interactive voice system or interactive web response system, and a permuted block randomisation scheme (block size of 4), to receive intravenous inebilizumab (300 mg) or identical placebo on days 1 and 15 of the randomised period, which lasted up to 197 days. Participants and all study staff were masked to treatment assignment. The primary endpoint of the randomised period of the trial was time to onset of adjudicated neuromyelitis optica spectrum disorder attack on or before day 197. Participants in the randomised controlled period who had an adjudicated attack, completed 197 days in the study, or were in the randomised controlled period when enrolment stopped, could voluntarily enter the open-label period. In the open-label period, participants either initiated inebilizumab if assigned placebo (receiving 300 mg on days 1 and 15 of the open-label period) or continued treatment if assigned inebilizumab (receiving 300 mg on day 1 and placebo on day 15, to maintain B-cell depletion and masking of the randomised controlled period). All participants subsequently received inebilizumab 300 mg every 6 months for a minimum of 2 years. The end-of-study analysis endpoints were time to adjudicated attack and annualised attack rate (assessed in all participants who received inebilizumab at any point during the randomised controlled period or open-label period [any inebilizumab population] and the aquaporin-4 [AQP4]-IgG seropositive subgroup [any inebilizumab-AQP4-IgG seropositive population]) and safety outcomes (in all participants who were exposed to inebilizumab, analysed as-treated). This study is registered with ClinicalTrials.gov, NCT02200770, and is now complete.

FINDINGS

Between Jan 6, 2015, and Sept 24, 2018, 467 individuals were screened, 231 were randomly assigned, and 230 received at least one dose of inebilizumab (n=174) or placebo (n=56). Between May 19, 2015, and Nov 8, 2018, 165 (95%) of 174 participants in the inebilizumab group and 51 (91%) of 56 in the placebo group entered the open-label period (mean age 42·9 years [SD 12·4], 197 [91%] of 216 were female, 19 [9%] were male, 115 [53%] were White, 45 [21%] were Asian, 19 [9%] were American Indian or Alaskan Native, and 19 [9%] were Black or African American). As of data cutoff for this end of study analysis (Dec 18, 2020; median exposure 1178 days [IQR 856-1538], total exposure of 730 person-years) 225 participants formed the any inebilizumab population, and 208 (92%) participants were AQP4-IgG seropositive. Overall, 63 adjudicated neuromyelitis optica spectrum disorder attacks occurred in 47 (21%) of 225 treated participants (60 attacks occurred in 44 [21%] of 208 in the AQP4-IgG seropositive subgroup); 40 (63%) of 63 attacks occurred in 34 (15%) of 225 treated participants during the first year of treatment. Of individuals who had an adjudicated attack while receiving inebilizumab, 36 (77%) of 47 were subsequently attack-free at the end of 4 years. Annualised attack rates decreased year-on-year, with end-of-study adjusted annualised attack rates being similar in the any inebilizumab-AQP4-IgG seropositive subgroup (0·097 [95% CI 0·070-0·14]) and any inebilizumab populations (0·092 [0·067-0·13]). Overall, 208 (92%) of 225 participants who received any inebilizumab had at least one treatment-emergent adverse event, the most frequent of which were urinary tract infection (59 [26%]), nasopharyngitis (47 [21%]), and arthralgia (39 [17%]). Infection rates did not increase over 4 years. Three (1%) of 225 participants in the any inebilizumab population died during the open-label period (one each due to a CNS event of unknown cause and pneumonia, respiratory insufficiency resulting from an neuromyelitis optica spectrum disorder attack and viral pneumonia related to COVID-19), all of which were deemed to be unrelated to treatment.

INTERPRETATION

Data from the end-of-study analysis of the N-MOmentum trial showed continued and sustained clinical benefits of long-term inebilizumab treatment in individuals with neuromyelitis optica spectrum disorder, which supports the role of inebilizumab as a CD19+ B-cell-depleting therapy in neuromyelitis optica spectrum disorder.

FUNDING

MedImmune and Viela Bio/Horizon Therapeutics, now part of Amgen.

Chimeric AQP4-based immunosorbent for highly-specific removal of AQP4-IgG from blood

Anti-aquaporin-4 autoantibodies (AQP4-IgG) are implicated in the pathogenesis of neuromyelitis optica spectrum disorders (NMOSD), and their removal from the blood circulation is considered to be an effective method for acute treatment. An ideal extracorporeal AQP4-IgG removal system should have high specificity, which means that it can selectively remove AQP4-IgG without affecting normal immunoglobulins. However, the conventional tryptophan immobilized column lacks sufficient specificity and cannot achieve this goal. In this study, we successfully prepared a fusion protein chimeric AQP4, which consists of the complete antigenic epitopes of human AQP4 and the constant region of scaffold protein DARPin. Chimeric AQP4 was expressed and purified from Escherichia coli, and then immobilized on agarose gel as a ligand for selective capture of AQP4-IgG immunosorbent. The prepared immunosorbent had a theoretical maximum adsorption capacity of 20.48 mg/g gel estimated by Langmuir isotherm. In vitro plasma perfusion tests demonstrated that the chimeric AQP4 coupled adsorbent had remarkable adsorption performance, and could eliminate more than 85 % of AQP4-IgG under the gel-to-plasma ratio of 1:50. Moreover, it exhibited high specificity because other human plasma proteins were not adsorbed in the dynamic adsorption experiment. These results suggest that the chimeric AQP4 coupled immunosorbent can provide a new approach for specific immunoadsorption (IA) treatment of NMOSD.

Therapeutic inertia in the management of neuromyelitis optica spectrum disorder

Introduction and objective

Limited information is available on how neurologists make therapeutic decisions in neuromyelitis optica spectrum disorder (NMOSD), especially when new treatments with different mechanisms of action, administration, and safety profile are being approved. Decision-making can be complex under this uncertainty and may lead to therapeutic inertia (TI), which refers to lack of treatment initiation or intensification when therapeutic goals are not met. The study aim was to assess neurologists' TI in NMOSD.

Methods

An online, cross-sectional study was conducted in collaboration with the Spanish Society of Neurology. Neurologists answered a survey composed of demographic characteristics, professional background, and behavioral traits. TI was defined as the lack of initiation or intensification with high-efficacy treatments when there is evidence of disease activity and was assessed through five NMOSD aquaporin-4 positive (AQP4+) simulated case scenarios. A multivariate logistic regression analysis was used to determine the association between neurologists' characteristics and TI.

Results

A total of 78 neurologists were included (median interquartile range [IQR] age: 36.0 [29.0-46.0] years, 55.1% male, median [IQR] experience managing demyelinating conditions was 5.2 [3.0-11.1] years). The majority of participants were general neurologists (59.0%) attending a median (IQR) of 5.0 NMOSD patients (3.0-12.0) annually. Thirty participants (38.5%) were classified as having TI. Working in a low complexity hospital and giving high importance to patient's tolerability/safety when choosing a treatment were predictors of TI.

Conclusion

TI is a common phenomenon among neurologists managing NMOSD AQP4+. Identifying TI and implementing specific intervention strategies may be critical to improving therapeutic decisions and patient care.

Correlation of GABA+ levels in the medial prefrontal cortex and circulating follicular helper T cells in neuromyelitis optica spectrum disorder patients with cognitive impairment

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) associated with cognitive impairment (CI) is acknowledged. However, the underlying pathogenesis and involvement of the immune system remain unclear.

OBJECTIVES

This study aimed to investigate the alterations in immune cells, cytokines, and GABA+ levels in NMOSD patients with cognitive deficits.

METHODS

Thirty-eight NMOSD patients and 38 healthy controls (HCs) were included. NMOSD patients were stratified as NMOSD-CI and NMOSD-CP groups. The difference in cognitive functions, Tfh and cytokines, and GABA+ levels were assessed, and their correlations were calculated.

RESULTS

NMOSD-CI patients showed worse performance on all cognitive tests, and the percentage of circulating follicular helper T cells (cTfh) was significantly elevated. The frequency of cTfh was positively and negatively correlated with Stroop-A and AVLT long-delayed scores, respectively. IL-21 was remarkably higher in NMOSD-CI and NMOSD-CP. The level of GABA+ in medial prefrontal cortex (mPFC) was significantly decreased in NMOSD-CI and was proved positively and negatively correlated with Symbol Digit Modalities Test and the frequency of circulating Tfh cells, respectively.

CONCLUSION

In NMOSD-CI patients, all cognitive domains were impacted, , while GABA+ levels in mPFC were decreased. GABA+ levels in NMOSD-CI were negatively correlated with the frequency of cTfh, suggesting the underlying coupling mechanism between immune responses and neurotransmitter metabolism in CI in NMOSD patients.

Neuromyelitis Optica: A Case Report From a Radiological Perspective

Neuromyelitis optica (NMO), also known as Devic's disease, is a chronic inflammatory disorder of the optic nerve and the spinal cord. Similar to multiple sclerosis, it has a relapsing and remitting characteristic. The disease is characterized by optic neuritis and longitudinal extensive inflammation of the spinal cord. Magnetic resonance imaging (MRI) is the modality of choice for this disorder. The serological examination also shows the presence of aquaporin-4 (AQP4) autoantibodies. MRI shows longitudinal extensive transverse myelitis and signs of optic neuritis such as inflammation of the optic nerve. The treatment is based on intravenous corticosteroids with or without plasmapheresis. The current case is a 25-year-old African American male patient who presented with multiple sclerosis-like symptoms (i.e., optic neuritis and transverse myelitis) but turned out to have NMO. Serological examination reveals the absence of AQP4 autoantibodies. A radiological examination showed swelling in the cervical cord. This case report strongly focuses on the radiological findings of NMO.

An update on biologic treatments for neuromyelitis optica spectrum disorder

INTRODUCTION

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disease of the central nervous system mediated by antibodies targeting the aquaporin-4 (AQP4) water channel expressed on astrocytes. The binding of specific antibodies to AQP4 causes complement-dependent cytotoxicity, leading to inflammation and demyelination. Several recent phase 2 and 3 randomized placebo-controlled trials showed the efficacy and safety of monoclonal antibody therapies targeting B-cells, interleukin-6 receptor, and complement.

AREAS COVERED

Current biologic treatments for NMOSD and developments therein, and unresolved issues in NMOSD treatment.

EXPERT OPINION

New biologic treatments demonstrate high efficacy and good safety for patients with AQP4-IgG-positive NMOSD. The optimal therapeutics for seronegative NMOSD, pediatric patients, and female patients who are pregnant or wish to be are unclear, and further research is needed. Also, real-world studies of new biological agents and the data on the durability of their beneficial effects and their long-term safety are required. Effective rescue therapy for an acute attack is critical given permanent disability in NMOSD is attack-related, and biologic agents that treat acute attack are emerging. If such treatments are to become widely applied, studies on the most cost-effective treatment strategies are needed.

Treatment and Relapse Prevention of Typical and Atypical Optic Neuritis

Optic neuritis (ON) is an inflammatory condition involving the optic nerve. Several important typical and atypical ON variants are now recognized. Typical ON has a more favorable prognosis; it can be idiopathic or represent an early manifestation of demyelinating diseases, mostly multiple sclerosis (MS). The atypical spectrum includes entities such as antibody-driven ON associated with neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein antibody disease (MOGAD), chronic/relapsing inflammatory optic neuropathy (CRION), and sarcoidosis-associated ON. Appropriate and timely diagnosis is essential to rapidly decide on the appropriate treatment, maximize visual recovery, and minimize recurrences. This review paper aims at presenting the currently available state-of-the-art treatment strategies for typical and atypical ON, both in the acute phase and in the long-term. Moreover, emerging therapeutic approaches and novel steps in the direction of achieving remyelination are discussed.

Neuromyelitis Optica Spectrum Disorders

PURPOSE OF REVIEW

This article reviews the cardinal clinical features, distinct immunopathology, current diagnostic criteria, relapse-related risk factors, emerging biomarkers, and evolving treatment strategies pertaining to neuromyelitis optica spectrum disorders (NMOSD).

RECENT FINDINGS

The discovery of the pathogenic aquaporin-4 (AQP4)-IgG autoantibody and characterization of NMOSD as an autoimmune astrocytopathy have spearheaded the identification of key immunologic therapeutic targets in this disease, including but not limited to the complement system, the interleukin 6 (IL-6) receptor, and B cells. Accordingly, four recent randomized controlled trials have demonstrated the efficacy of three new NMOSD therapies, namely eculizumab, satralizumab, and inebilizumab.

SUMMARY

Currently, NMOSD poses both diagnostic and treatment challenges. It is debated whether individuals who are seropositive for myelin oligodendrocyte glycoprotein (MOG)-IgG belong within the neuromyelitis optica spectrum. This discussion is fueled by disparities in treatment responses between patients who are AQP4-IgG seropositive and seronegative, suggesting different immunopathologic mechanisms may govern these conditions. As our understanding regarding the immune pathophysiology of NMOSD expands, emerging biomarkers, including serum neurofilament light chain and glial fibrillary acidic protein (GFAP), may facilitate earlier relapse detection and inform long-term treatment decisions. Future research focal points should include strategies to optimize relapse management, restorative treatments that augment neurologic recovery, and practical solutions that promote equitable access to approved therapies for all patients with NMOSD.

Optic Neuritis in the Era of NMOSD and MOGAD: A Survey of Practice Patterns in Singapore

PURPOSE

The Optic Neuritis Treatment Trial was a landmark study with implications worldwide. In the advent of antibody testing for neuromyelitis optica spectrum disease (NMOSD) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), emerging concepts, such as routine antibody testing and management, remain controversial, resulting mostly from studies in White populations. We evaluate the practice patterns of optic neuritis investigation and management by neuro-ophthalmologists and neurologists in Singapore.

DESIGN

21-question online survey consisting of 4 clinical vignettes.

METHODS

The survey was sent to all Singapore Medical Council- registered ophthalmologists and neurologists who regularly manage patients with optic neuritis.

RESULTS

Forty-two recipients (17 formally trained neuro-ophthalmol-ogists [100% response rate] and 25 neurologists) responded. Participants opted for routine testing of anti-aquaporin-4 antibodies (88.1% in mild optic neuritis and 97.6% in severe optic neuritis). Anti-MOG antibodies were frequently obtained (76.2% in mild and 88.1% in severe optic neuritis). Plasmapheresis was rapidly initiated (85.7%) in cases of nonresponse to intravenous steroids, even before obtaining anti-aquaporin-4 or anti-MOG serology results. In both NMOSD and MOGAD, oral mycophenolate mofetil was the preferred option if chronic immunosuppression was necessary. Steroids were given for a longer duration and tapered more gradually than in idiopathic optic neuritis cases.

CONCLUSIONS

Serological testing for NMOSD and MOGAD is considered as a routine procedure in cases of optic neuritis in Singapore, possibly due to local epidemiological features of these conditions. Chronic oral immunosuppression is preferred for the long term, but further research is necessary to establish the efficacy and cost-effectiveness of these practices.

Expression and Clinical Correlation Analysis Between Repulsive Guidance Molecule a and Neuromyelitis Optica Spectrum Disorders

Objectives

This study sought to explore the expression patterns of repulsive guidance molecules a (RGMa) in neuromyelitis optica spectrum disorders (NMOSD) and to explore the correlation between RGMa and the clinical features of NMOSD.

Methods

A total of 83 NMOSD patients and 22 age-matched healthy controls (HCs) were enrolled in the study from October 2017 to November 2021. Clinical parameters, including Expanded Disability Status Scale (EDSS) score, degree of MRI enhancement, and AQP4 titer were collected. The expression of serum RGMa was measured by enzyme-linked immunosorbent assay (ELISA) and compared across the four patient groups. The correlation between serum RGMa levels and different clinical parameters was also assessed.

Results

The average serum expression of RGMa in the NMOSD group was significantly higher than that in the HC group (p < 0.001). Among the patient groups, the acute phase group exhibited significantly higher serum RGMa levels than did the remission group (p < 0.001). A multivariate analysis revealed a significant positive correlation between RGMa expression and EDSS score at admission, degree of MRI enhancement, and segmental length of spinal cord lesions. There was a significant negative correlation between the expression of RGMa in NMOSD and the time from attack to sampling or delta EDSS.

Conclusions

The current study suggests that RGMa may be considered a potential biomarker predicting the severity, disability, and clinical features of NMOSD.

Can Immune Tolerance Be Re-established in Neuromyelitis Optica?

Neuromyelitis optica (NMO) is a chronic inflammatory disease of the central nervous system that primarily affects the optic nerves and spinal cord of patients, and in some instances their brainstem, diencephalon or cerebrum as spectrum disorders (NMOSD). Clinical and basic science knowledge of NMO has dramatically increased over the last two decades and it has changed the perception of the disease as being inevitably disabling or fatal. Nonetheless, there is still no cure for NMO and all the disease-modifying therapies (DMTs) are only partially effective. Furthermore, DMTs are not disease- or antigen-specific and alter all immune responses including those protective against infections and cancer and are often associated with significant adverse reactions. In this review, we discuss the pathogenic mechanisms of NMO as they pertain to its DMTs and immune tolerance. We also examine novel research therapeutic strategies focused on induction of antigen-specific immune tolerance by administrating tolerogenic immune-modifying nanoparticles (TIMP). Development and implementation of immune tolerance-based therapies in NMO is likely to be an important step toward improving the treatment outcomes of the disease. The antigen-specificity of these therapies will likely ameliorate the disease safely and effectively, and will also eliminate the clinical challenges associated with chronic immunosuppressive therapies.