Rituximab maintenance treatment outcomes in patients with relapsing neuromyelitis optica spectrum disorder: a monocentric retrospective analysis

Some patients with neuromyelitis optica spectrum disorder (NMOSD) experience relapse after rituximab (RTX) treatment. In this retrospective study, we analyzed the recurrence-related clinical features, laboratory investigation results, and dosing protocol of 30 female patients with relapsing NMOSD with immunoglobulin G autoantibodies against aquaporin-4 and relapses during repeated 0.5 g RTX infusions as maintenance treatment. The median follow-up period was 6.62 years. Thirty-five episodes were observed, with myelitis being the most frequent. The median expanded disability status scale change score was 0.50. The recurrence rate decreased by 44.23%/year with RTX infusion. Approximately 85.71% of the patients showed relapse without RTX infusion within 10 months. Overall, RTX may be effective for relapsing NMOSD cases.

Comparison of clinico-radiological profile, optical coherence tomography parameters, and outcome in MOGAD and Neuromyelitis optica spectrum disorder subtypes: A prospective observational study

Objectives

The objectives of the study were to compare the clinico-radiological profile, optical coherence tomography (OCT) parameters and outcome in Myelin Oligodendrocyte Glycoprotein-IgG-associated disorders (MOGAD) and Neuromyelitis Optica Spectrum disorder subtypes.

Materials and Methods

This prospective study involved collection of data regarding neurological assessment, neuroimaging, cerebrospinal fluid analysis, OCT parameters, treatment and outcome. Disease severity and disability were assessed using Expanded Disability Status Scale and modified Rankin scale. Patients were categorized into aquaporin-4 (AQP4+), MOGAD, and double negative (DN; both AQP4 and MOG negative).

Results

Among 31 patients included, 42% were AQP4+, 32.2% were MOGAD, and 25.7% were DN. The median age at onset was comparable (AQP4+ vs. MOGAD vs. DN = 28 years vs. 24.4 years vs. 31.5years; P = 0.31). Females predominated in AQP4+ compared to MOGAD group (76.9% vs. 30%; P = 0.02). Majority of patients (73.5%) had a relapsing course with a median of two (range = 1-9) relapses. Ninety-nine demyelinating events occurred: Transverse myelitis (TM) in 60/99 (60.6%), optic neuritis (ON) in 43/99 (43.4%), area postrema (AP) syndrome in 20/99 (20.1%), and optico-spinal syndrome in 10/99 (10.1%). ON was common in MOGAD than AQP4+ patients (58.6% vs. 32.1%; P = 0.03). Spinal cord and brain lesions on magnetic resonance imaging (MRI) were seen in 90.3% and 54.8% patients, respectively. A significantly higher proportion of AQP4+ patients showed longitudinally extensive transverse myelitis as compared to MOGAD group (69.2 % vs. 20 %; P = 0.04), specifically involving dorsal cord (92.3% vs. 50%; P = 0.02). MRI brain lesions, especially involving AP, was frequent in DN than MOGAD (47.1% vs. 6.9%; P = 0.003) and AQP4+ (47.1% vs. 18.9%; P = 0.03) patients. AQP4+ group showed significant nasal RNFL thinning on OCT (P = 0.04). Although 6-month good functional outcome was better in MOGAD than DN and AQP4+ (80% vs. 71.4% vs. 41.7%) groups, they were comparable (P = 0.13).

Conclusion

Nearly three-fourth of our patients showed a relapsing course, with TM being the most common clinical presentation. AQP4+ group showed female preponderance, frequent dorsal cord longitudinally extensive transverse myelitis, less frequent ON, and greater nasal RNFL thinning compared to MOGAD group. MRI brain lesions were more common in DN patients. All three groups exhibited good response to pulse corticosteroids and showed a comparable functional outcome at 6-month follow-up.

Cells to the Rescue: Emerging Cell-Based Treatment Approaches for NMOSD and MOGAD

Cell-based therapies are gaining momentum as promising treatments for rare neurological autoimmune diseases, including neuromyelitis optica spectrum disorders and myelin oligodendrocyte glycoprotein antibody-associated disease. The development of targeted cell therapies is hampered by the lack of adequate animal models that mirror the human disease. Most cell-based treatments, including HSCT, CAR-T cell, tolerogenic dendritic cell and mesenchymal stem cell treatment have entered early stage clinical trials or have been used as rescue treatment in treatment-refractory cases. The development of antigen-specific cell-based immunotherapies for autoimmune diseases is slowed down by the rarity of the diseases, the lack of surrogate outcomes and biomarkers that are able to predict long-term outcomes and/or therapy effectiveness as well as challenges in the manufacturing of cellular products. These challenges are likely to be overcome by future research.

A comparison of the effects of rituximab versus other immunotherapies for MOG-IgG-associated central nervous system demyelination: A meta-analysis

BACKGROUND

Myelin oligodendrocyte glycoprotein (MOG) antibody disease (MOG-AD) is now recognised as a nosological entity with specific clinical and paraclinical features to aid early diagnosis. Rituximab (RTX) is a chimeric monoclonal antibody directed against CD20 epitope expressed on pre-B and mature B cells and is used to treat B-cell-derived lymphoid neoplasms and antibody-mediated autoimmune diseases. In this review, we performed a meta-analysis to evaluate RTX efficacy and assessed the treatment efficacies based on relapse rates.

METHODS

This study was conducted according to the PRISMA (Preferred Reporting Items for Systemic review and Meta-Analysis) statement. We searched for publications on the PubMed, Embase, Cochrane Library, clinical trials up to December 2020. We compiled 5 studies, Meta-analysis forest plots was conducted for the ARR ratio change pre and post-treatment between rituximab and other disease modifying drugs. A sensitivity analysis was performed with mean difference (MD) of the efficacy of RTX versus other immunotherapies and subgroup analysis was also performed based on site of study.

RESULTS

A meta-analysis of 5 studies with 239 participants was conducted. Patients have received rituximab were recorded in 82 of 239 (34.31%). The mean difference of ARR ratio of rituximab therapy versus other immunotherapies was 0.16 (95%CI, -0.15 to 0.47). No studies found to significantly affect heterogeneity. No major differences occurred in 9.2% of China patients (95% CI: -0.20-1.86; I2=0%) and 90.8% of non- China patients (95% CI: -0.24-0.42; I2=0%). Meanwhile there was no significant subgroup difference (p = 0.18) between them.

CONCLUSION

RTX reduces the relapse frequency in most patients with MOG antibody disease, but there is no differences between rituximab and other immunotherapies in MOG antibody disease. Future a large multicenter randomized controlled clinical trial to thoroughly characterize the efficacy of rituximab for MOG antibody disease is necessary.

Use of therapeutic plasma exchange for pediatric neurological diseases

Therapeutic plasma exchange is used to treat neurological diseases in the pediatric population. Since its first use in pediatric patients with hepatic coma in the form of manual whole blood exchange, therapeutic plasma exchange has been increasingly used to treat these disorders of the nervous system. This expansion is a result of improved techniques and apheresis instruments suitable for small children, as well as the recognition of its applicability to many diseases in the pediatric population. This review provides a historical overview of the use of therapeutic apheresis in children and highlights the most common applications for therapeutic plasma exchange to treat neurological disorders in children.

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.

Emerging therapeutic targets for neuromyelitis optica spectrum disorder

Introduction: Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory demyelinating disease of the central nervous system affecting primarily the spinal cord and optic nerves. Most NMOSD patients are seropositive for immunoglobulin G autoantibodies against astrocyte water channel aquaporin-4, called AQP4-IgG, which cause astrocyte injury leading to demyelination and neurological impairment. Current therapy for AQP4-IgG seropositive NMOSD includes immunosuppression, B cell depletion, and plasma exchange. Newer therapies target complement, CD19 and IL-6 receptors.Areas covered: This review covers early-stage pre-clinical therapeutic approaches for seropositive NMOSD. Targets include pathogenic AQP4-IgG autoantibodies and their binding to AQP4, complement-dependent and cell-mediated cytotoxicity, blood-brain barrier, remyelination and immune effector and regulatory cells, with treatment modalities including small molecules, biologics, and cells.Expert opinion: Though newer NMOSD therapies appear to have increased efficacy in reducing relapse rate and neurological deficit, increasingly targeted therapies could benefit NMOSD patients with ongoing relapses and could potentially be superior in efficacy and safety. Of the various early-stage therapeutic approaches, IgG inactivating enzymes, aquaporumab blocking antibodies, drugs targeting early components of the classical complement system, complement regulator-targeted drugs, and Fc-based multimers are of interest. Curative strategies, perhaps involving AQP4 tolerization, remain intriguing future possibilities.

Disease Course and Treatment Responses in Children With Relapsing Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease

Importance

Myelin oligodendrocyte glycoprotein antibodies (MOG-Abs) are consistently identified in a range of demyelinating disorders in adults and children. Current therapeutic strategies are largely center specific, and no treatments have been formally evaluated.

Objective

To examine the clinical phenotypes, treatment responses, and outcomes of children with relapsing MOG-Ab-associated disease.

Design, Setting, and Participants

This study prospectively collected demographic, clinical, and radiologic data from 102 patients from 8 countries of the EU Paediatric Demyelinating Disease Consortium from January 1, 2014, through December 31, 2016. Patients were treated according to local protocols.

Main Outcomes and Measures

Annualized relapse rates (ARRs) and Expanded Disability Status Scale (EDSS) scores before and during treatment with disease-modifying drugs (DMDs).

Results

A total of 102 children were identified (median [range] age, 7.0 [1.5-7.9] years; male to female ratio, 1.0:1.8; white to other race/ethnicity ratio, 3.6:1.0). Original diagnoses were neuromyelitis optica spectrum disorder (44 patients [43.1%]), acute disseminated encephalomyelitis followed by optic neuritis (20 [19.6%]), multiphasic disseminated encephalomyelitis (20 [19.6%]), and relapsing optic neuritis (18 [17.6%]). In all, 464 demyelinating events were reported. Treated patients had more relapses (median, 3.0; range, 1.0-17.0) than untreated patients (median, 1.0; range 1.0-7.0) (P = .009) and higher EDSS scores (median, 1.5; interquartile range, 0-2.5) than untreated patients (median, 1.0; interquartile range, 0-1.5) (P < .001). Fifty-two children (51.0%) received DMDs: 28 (53.8%) were treated with 1 DMD, 17 (32.7%) with 2, and 7 (13.5%) with 3 or more sequential DMDs. Patients relapsed during all treatments, with a total of 127 relapses on treatment reported. No changes in median ARR and EDSS score were observed between the preinitiation and postinitiation phases of interferon beta and glatiramer acetate treatment (n = 11). The median ARR was reduced from 1.84 to 1.0 with azathioprine (n = 20, P < .001), 1.79 to 0.52 with mycophenolate mofetil (n = 15, P = .003), and 2.12 to 0.67 with rituximab (n = 9, P < .001), although the median EDSS score remained unchanged. An improvement in ARR (from 2.16 to 0.51, P < .001) and EDSS score (from 2.2 to 1.2, P = .01) was observed in the 12 patients treated with regular intravenous immunoglobulins.

Conclusions and Relevance

Although commonly used to treat patients with multiple sclerosis, DMDs were not associated with clinical improvement in children with MOG-Ab-associated disease, whereas azathioprine, mycophenolate mofetil, rituximab, and particularly intravenous immunoglobulins were associated with a reduction in relapse frequency. A correct diagnosis of relapsing MOG-Ab-associated disorders is therefore important to optimize immune treatment.

Role of complement and potential of complement inhibitors in myasthenia gravis and neuromyelitis optica spectrum disorders: a brief review

The complement system is a powerful member of the innate immune system. It is highly adept at protecting against pathogens, but exists in a delicate balance between its protective functions and overactivity, which can result in autoimmune disease. A cascade of complement proteins that requires sequential activation, and numerous complement regulators, exists to regulate a proportionate response to pathogens. In spite of these mechanisms there is significant evidence for involvement of the complement system in driving the pathogenesis of variety of diseases including neuromyelitis optica spectrum disorders (NMOSD) and myasthenia gravis (MG). As an amplification cascade, there are an abundance of molecular targets that could be utilized for therapeutic intervention. Clinical trials assessing complement pathway inhibition in both these conditions have recently been completed and include the first randomized placebo-controlled trial in NMOSD showing positive results. This review aims to review and update the reader on the complement system and the evolution of complement-based therapeutics in these two disorders.

Immune-Mediated Myelopathies

PURPOSE OF REVIEW

This article reviews the clinical presentation, diagnostic evaluation, and management of immune-mediated myelopathies.

RECENT FINDINGS

The discovery of several neural autoantibodies and their antigenic targets has revolutionized the investigation and treatment of immune-mediated myelopathies. Detection of these serologic biomarkers can support or establish a diagnosis of an autoimmune myelopathy, and, in the case of paraneoplastic syndromes, indicate the likely presence of an underlying malignancy. Distinctive lesion patterns detected on spinal cord or brain MRI narrow the differential diagnosis in patients with acute or subacute inflammatory myelopathies, including those not associated with autoantibody markers.

SUMMARY

Immune-mediated myelopathies usually present acutely or subacutely and have a broad differential diagnosis. A systematic diagnostic approach using data from the clinical setting and presentation, MRI lesion patterns, CSF data, and autoantibody markers can differentiate these disorders from noninflammatory myelopathies, often with precise disease classification. This, in turn, provides prognostic information, especially whether the disorder is likely to relapse, and facilitates therapeutic decision making. Diagnostic accuracy informs selection of acute immunotherapy aimed at arresting and reversing recent neurologic injury and, when necessary, selection of long-term treatment for prevention of disease progression or relapse.

CD55 upregulation in astrocytes by statins as potential therapy for AQP4-IgG seropositive neuromyelitis optica

Background

Neuromyelitis optica spectrum disorder (herein called NMO) is an inflammatory demyelinating disease that can be initiated by binding of immunoglobulin G autoantibodies (AQP4-IgG) to aquaporin-4 on astrocytes, causing complement-dependent cytotoxicity (CDC) and downstream inflammation. The increased NMO pathology in rodents deficient in complement regulator protein CD59 following passive transfer of AQP4-IgG has suggested the potential therapeutic utility of increasing the expression of complement regulator proteins.

Methods

A cell-based ELISA was developed to screen for pharmacological upregulators of endogenous CD55 and CD59 in a human astrocyte cell line. A statin identified from the screen was characterized in cell culture models and rodents for its action on complement regulator protein expression and its efficacy in models of seropositive NMO.

Results

Screening of ~ 11,500 approved and investigational drugs and nutraceuticals identified transcriptional upregulators of CD55 but not of CD59. Several statins, including atorvastatin, simvastatin, lovastatin, and fluvastatin, increased CD55 protein expression in astrocytes, including primary cultures, by three- to four-fold at 24 h, conferring significant protection against AQP4-IgG-induced CDC. Mechanistic studies revealed that CD55 upregulation involves inhibition of the geranylgeranyl transferase pathway rather than inhibition of cholesterol biosynthesis. Oral atorvastatin at 10–20 mg/kg/day for 3 days strongly increased CD55 immunofluorescence in mouse brain and spinal cord and reduced NMO pathology following intracerebral AQP4-IgG injection.

Conclusion

Atorvastatin or other statins may thus have therapeutic benefit in AQP4-IgG seropositive NMO by increasing CD55 expression, in addition to their previously described anti-inflammatory and immunomodulatory actions.

Brain and cord imaging features in neuromyelitis optica spectrum disorders

OBJECTIVES

To validate imaging features able to discriminate neuromyelitis optica spectrum disorders from multiple sclerosis with conventional magnetic resonance imaging (MRI).

METHODS

In this cross-sectional study, brain and spinal cord scans were evaluated from 116 neuromyelitis optica spectrum disorder patients (98 seropositive and 18 seronegative) in chronic disease phase and 65 age-, sex-, and disease duration-matched multiple sclerosis patients. To identify independent predictors of neuromyelitis optica diagnosis, after assessing the prevalence of typical/atypical findings, the original cohort was 2:1 randomized in a training sample (where a multivariate logistic regression analysis was run) and a validation sample (where the performance of the selected variables was tested and validated).

RESULTS

Typical brain lesions occurred in 50.9% of neuromyelitis optica patients (18.1% brainstem periventricular/periaqueductal, 32.7% periependymal along lateral ventricles, 3.4% large hemispheric, 6.0% diencephalic, 4.3% corticospinal tract), 72.2% had spinal cord lesions (46.3% long transverse myelitis, 36.1% short transverse myelitis), 37.1% satisfied 2010 McDonald criteria, and none had cortical lesions. Fulfillment of at least 2 of 5 of absence of juxtacortical/cortical lesions, absence of periventricular lesions, absence of Dawson fingers, presence of long transverse myelitis, and presence of periependymal lesions along lateral ventricles discriminated neuromyelitis optica patients in both training (sensitivity = 0.92, 95% confidence interval [CI] = 0.84-0.97; specificity = 0.91, 95% CI = 0.78-0.97) and validation samples (sensitivity = 0.82, 95% CI = 0.66-0.92; specificity = 0.91, 95% CI = 0.71-0.99). MRI findings and criteria performance were similar irrespective of serostatus.

INTERPRETATION

Although up to 50% of neuromyelitis optica patients have no typical lesions and a relatively high percentage of them satisfy multiple sclerosis criteria, several easily applicable imaging features can help to distinguish neuromyelitis optica from multiple sclerosis. ANN NEUROL 2019;85:371-384.

Importance of Regular and Maintenance Therapy Adherence in Neuromyelitis Optica (NMO): Lessons from a Repeating Relapse Case

Patient: Female, 58

Final Diagnosis: NMO

Symptoms: New-onset right leg weakness and pain

Medication: —

Clinical Procedure: Progressive and recurring

Specialty: Neurology

Comparison of efficacy and tolerability of azathioprine, mycophenolate mofetil, and lower dosages of rituximab among patients with neuromyelitis optica spectrum disorder

OBJECTIVE

To observe and compare the efficacy and tolerability of azathioprine (AZA), mycophenolate mofetil (MMF) and lower dosages of rituximab (RTX) among patients with neuromyelitis optica spectrum disorder.

METHODS

In this prospective cohort, AQP4-IgG-seropositive patients with neuromyelitis optica spectrum disorder (NMOSD) were enrolled and randomly divided into three groups, using AZA, MMF or lower dosages of RTX (defined as 100mg RTX intravenous injection, once per week for 4 consecutive weeks) respectively. Annualized relapse rate (ARR), EDSS scores, CD19+ B-cell counts in peripheral blood, serum AQP-4-IgG titre and drug adverse reactions were compared between three groups.

RESULTS

In the AZA group (n=22), MMF group (n=30) and RTX group (n=20), 54.5%, 60.0% and 65.0% of patients reached a relapse-free state and EDSS score improved in 90.9%, 83.3% and 90.0% of patients respectively. In addition, there was significant reduction in ARR in all the three groups. Reduced dosage of RTX exerted a significant effect in reducing CD19+ B-cell counts (P<0.01). Compared with the AZA group, the MMF group and the RTX group decreased the AQP-4-IgG titre evidently and caused fewer adverse events. Neither the Kaplan-Meier survival curves nor the Cox proportional hazard model indicated a significant difference in relapse among the three groups (P>0.05).

CONCLUSIONS

AZA, MMF and reduced dosages of rituximab are all effective in reducing ARR and improving the clinical symptom of patients with NMOSD. Lower dosages of RTX are more effective than the others in decreasing the CD19 B-cell counts. MMF and reduced RTX decrease AQP-4-IgG titre more and cause fewer adverse events than AZA. However, more multicentre studies are still needed to find more effective therapeutic regimen.

A mathematical model of cellular swelling in Neuromyelitis optica

Neuromyelitis Optica (NMO) is a severe neuro-inflammatory disease of the central nervous system characterized by predominant damage to the optic nerve and of the spinal cord. The pathogenic antibody found in the majority of patients targets the AQP4 channels on astrocytic endfeet and causes the cells to swell. Although, the pathophysiology of the disease is broadly known, there are no specific targeted treatments for this process clinically available nor accurate prognostic markers both during attacks and for predicting long term neuronal damage. This lack is, in part, due to the rarity of the disease and its relatively recent pathogenic clarity. Hence, the ability to mathematically model the progress of the condition to test prospective therapies in silico would be a step forward. This paper combines state of the art models of cellular metabolism and cytotoxic oedema in neurons and astrocytes and augments it with a detailed characterization of water transport across the cellular membrane. In particular, we capture the process of perforation of the cell through the human complement cascade and resulting water and ionic fluxes. Simulating NMO by injecting its antibody and human complement into the extracellular space showed a 25% increase of the astrocytic volume after 12 h from onset. Most of the volume change occurred during the first 30 min of simulation with a peak volume change of 38%. The model was further adapted to simulate the therapeutic potential of CD59. It was found that there is a threshold of CD59 concentration that can prevent the swelling of astrocytes. Since the astrocyte volume changes mostly during the first hour, further experimental work should focus on this time scale to provide data for further model refinement and validation.

Aquaporin modulators: a patent review (2010-2015)

INTRODUCTION

Since the discovery of aquaporin-1 (AQP1) as a water channel, more than 2,000 articles, reviews and chapters have been published. The wide tissue expression, functional and biological roles have documented the major and essential physiological importance of these channels both in health and disease. Thus, over the years, studies have revealed essential importance of aquaporins in mammalian pathophysiology revealing aquaporins as potential drug targets. Areas covered: Starting from a brief description of the main structural and functional features of aquaporins, their roles in physiology and pathophysiology of different human diseases, this review describes the main classes of small molecules and biologicals patented, published from 2010 to 2015, able to regulate AQPs for diagnostic and therapeutic applications. Expert opinion: Several patents report on AQP modulators, mostly inhibitors, and related pharmaceutical formulations, to be used for treatments of water imbalance disorders, such as edema. Noteworthy, a unique class of gold-based compounds as selective inhibitors of aquaglyceroporin isoforms may provide new chemical tools for therapeutic applications, especially in cancer. AQP4-targeted therapies for neuromyelitis optica, enhancement of AQP2 function for nephrogenic diabetes insipidus and AQP1-5 gene transfer for the Sjogren's syndrome represent promising therapies that deserve further investigation by clinical trials.