Eculizumab in Aquaporin-4-Positive Neuromyelitis Optica Spectrum Disorder

Antibody-mediated complement activation in pathology and protection

Antibody-dependent complement activity is associated not only with autoimmune morbidity, but also with antitumor efficacy. In infectious disease, both recombinant monoclonal antibodies and polyclonal antibodies generated in natural adaptive responses can mediate complement activity to protective, therapeutic or disease-enhancing effect. Recent advances have contributed to the structural resolution of molecular complexes involved in antibody-mediated complement activation, defining the avid nature of participating interactions and pointing to how antibody isotype, subclass, hinge flexibility, glycosylation state, amino acid sequence and the contextual nature of the cognate antigen/epitope are all factors that can determine complement activity through impact on antibody multimerization and subsequent recruitment of complement component 1q. Beyond the efficiency of activation, complement activation products interact with various cell types that mediate immune adherence, trafficking, immune education and innate functions. Similarly, depending on the anatomical location and extent of activation, complement can support homeostatic restoration or be leveraged by pathogens or neoplasms to enhance infection or promote tumorigenic microenvironments, respectively. Advances in means to suppress complement activation by intravenous immunoglobulin (IVIG), IVIG mimetics and complement-intervening antibodies represent proven and promising exploratory therapeutic strategies, while antibody engineering has likewise offered frameworks to enhance, eliminate or isolate complement activation to interrogate in vivo mechanisms of action. Such strategies promise to support the optimization of antibody-based drugs that are able to tackle emerging and difficult-to-treat diseases by improving our understanding of the synergistic and antagonistic relationships between antibody mechanisms mediated by Fc receptors, direct binding and the products of complement activation.

Effectiveness of subcutaneous tocilizumab in neuromyelitis optica spectrum disorders

BACKGROUND

Tocilizumab (TCZ), a humanized monoclonal antibody against the interleukin-6 receptor, is approved for treatment of rheumatoid arthritis and several other immune-mediated disorders. Off-label use of the intravenous formulation of tocilizumab for Neuromyelitis Optica Spectrum Disorder (NMOSD) decreased relapse rates in two small case series. However, treatment protocol that requires frequent intravenous infusions may adversely affect adherence to therapy, especially in the more disabled patients, thereby reducing effectiveness. A subcutaneous formulation of tocilizumab was shown to be noninferior to the IV formulation for approved rheumatologic diseases. The effectiveness of subcutaneous TCZ for NMOSD is unknown.

METHODS

We retrospectively reviewed clinical, radiological and serological data on all NMOSD patients who received subcutaneous TCZ in two tertiary referral centers between 2014-2019.

RESULTS

Twelve NMOSD patients who received at least 6 months of subcutaneous TCZ were identified. Eleven were female; mean age was 46.9 ± 14.5 years and mean disease duration was 6.6 ± 4.6 years. Seven patients were seropositive for AQP-4 antibodies, two - for MOG-IgG antibodies, and three were doubly seronegative. During subcutaneous TCZ treatment, eight patients (66.6%) were relapse-free, one patient (8.3%) experienced 1 relapse, two patients (16.6%) - 2 relapses, and one patient (8.3%) - 3 relapses. The median relapse rate within 1 year after starting subcutaneous TCZ - 0 (interquartile range =1.75-0) - was significantly lower than in the year prior to treatment initiation (2, interquartile range = 4.0-0.25; p = 0.04). Overall, the annual relapse rate (ARR) decreased from a median of 2 (interquartile range = 5.75-1.29) prior to subcutaneous TCZ to 0 (interquartile range= = 1.0-0) on treatment (p = 0.0015). One TCZ-treated patient died following a severe myelitis attack.

CONCLUSIONS

Effectiveness of subcutaneous TCZ in NMOSD appears to be similar to that reported for the IV formulation and has an advantage of at-home administration. Prospective, comparative studies of subcutaneous TCZ for NMOSD are warranted.

Safety and efficacy of rituximab in neuromyelitis optica spectrum disorders (RIN-1 study): a multicentre, randomised, double-blind, placebo-controlled trial

BACKGROUND

Pharmacological prevention against relapses in patients with neuromyelitis optica spectrum disorder (NMOSD) is developing rapidly. We aimed to investigate the safety and efficacy of rituximab, an anti-CD20 monoclonal antibody, against relapses in patients with NMOSD.

METHODS

We did a multicentre, randomised, double-blind, placebo-controlled clinical trial at eight hospitals in Japan. Patients aged 16-80 years with NMOSD who were seropositive for aquaporin 4 (AQP4) antibody, were taking 5-30 mg/day oral steroids, and had an Expanded Disability Status Scale (EDSS) score of 7·0 or less were eligible for the study. Individuals taking any other immunosuppressants were excluded. Participants were randomly allocated (1:1) either rituximab or placebo by a computer-aided dynamic random allocation system. The doses of concomitant steroid (converted to equivalent doses of prednisolone) and relapses in previous 2 years were set as stratification factors. Participants and those assessing outcomes were unaware of group assignments. Rituximab (375 mg/m²) was administered intravenously every week for 4 weeks, then 6-month interval dosing was done (1000 mg every 2 weeks, at 24 weeks and 48 weeks after randomisation). A matching placebo was administered intravenously. Concomitant oral prednisolone was gradually reduced to 2-5 mg/day, according to the protocol. The primary outcome was time to first relapse within 72 weeks. Relapses were defined as patient-reported symptoms or any new signs consistent with CNS lesions and attributable objective changes in MRI or visual evoked potential. The primary analysis was done in the full analysis set (all randomly assigned patients) and safety analyses were done in the safety analysis set (all patients who received at least one infusion of assigned treatment). The primary analysis was by intention-to-treat principles. This trial is registered with the UMIN clinical trial registry, UMIN000013453.

FINDINGS

Between May 10, 2014, and Aug 15, 2017, 38 participants were recruited and randomly allocated either rituximab (n=19) or placebo (n=19). Three (16%) patients assigned rituximab discontinued the study and were analysed as censored cases. Seven (37%) relapses occurred in patients allocated placebo and none were recorded in patients assigned rituximab (group difference 36·8%, 95% CI 12·3-65·5; log-rank p=0·0058). Eight serious adverse events were recorded, four events in three (16%) patients assigned rituximab (lumbar compression fracture and infection around nail of right foot [n=1], diplopia [n=1], and uterine cancer [n=1]) and four events in two (11%) people allocated to placebo (exacerbation of glaucoma and bleeding in the right eye chamber after surgery [n=1], and visual impairment and asymptomatic white matter brain lesion on MRI [n=1]); all patients recovered. No deaths were reported.

INTERPRETATION

Rituximab prevented relapses for 72 weeks in patients with NMOSD who were AQP4 antibody-positive. This study is limited by its small sample size and inclusion of participants with mild disease activity. However, our results suggest that rituximab could be useful maintenance therapy for individuals with NMOSD who are AQP4 antibody-positive.

FUNDING

Japanese Ministry of Health, Labour and Welfare, Japan Agency for Medical Research and Development, and Zenyaku Kogyo.

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.

Next-Generation Neuroimmunology: New Technologies to Understand Central Nervous System Autoimmunity

Understanding neuroimmunological disorders is essential for developing new diagnostic and therapeutic strategies. Rodent models have provided valuable insights, but are sometimes equated with their human counterparts. Here, we summarize how novel technologies may enable an improved human-focused view of immune mechanisms. Recent studies have applied these new technologies to the brain parenchyma, its surrounding cerebrospinal fluid, and peripheral immune compartments. Therapeutic interventions have also facilitated translational understanding in a reverse way. However, with improved technology, access to patient samples remains a rate-limiting step in translational research. We anticipate that next-generation neuroimmunology is likely to integrate, in the immediate future, diverse technical tools for optimal diagnosis, prognosis, and treatment of neuroimmunological disorders.

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.

Differentiate aquaporin-4 antibody negative neuromyelitis optica spectrum disorders from multiple sclerosis by multimodal advanced MRI techniques

BACKGROUND

It is clinically essential to distinguish aquaporin-4 antibody (AQP4-Ab) negative neuromyelitis optica spectrum disorders (NMOSD) and multiple sclerosis (MS) because of different therapeutic strategies. Since clinical and lesion features may not allow the distinction, we aimed to identify advanced imaging features that could improve the distinction between two disorders.

METHODS

Multimodal imaging measures included fractional anisotropy, mean, axial, radial diffusivity (MD, AD, RD) and kurtosis (MK, AK, RK) from diffusion kurtosis imaging; functional connectivity strength (FCS) and density, regional homogeneity, amplitude of low frequency fluctuations from resting-state functional MRI; gray matter volume from structural MRI; and cerebral blood flow from arterial spin labeling imaging. Voxel-wise comparisons were performed to identify inter-group differences in imaging measures, and the performance of differentiating these two disorders was estimated by receiver operating characteristic curves.

RESULTS

Compared to MS, patients with AQP4-Ab negative NMOSD showed decreased MD and AD but increased MK and AK in white matter regions; and reduced FCS in the occipital cortex (P < 0.05, FWE corrected). The joint-use of these five imaging measures distinguished the two disorders with an accuracy of 94% (P < 0.001, 95%CI = 0.84-0.98). Other imaging measures showed no significant differences between the two patient groups.

CONCLUSIONS

The study showed less white matter damage and a more severe functional disconnection of the occipital cortex in patients with AQP4-Ab negative NMOSD compared to MS. The combined use of diffusion and functional connectivity could facilitate a better distinction between NMO and MS with seronegative AQP4-Ab in clinical management.

Diagnostic procedures in suspected attacks in patients with neuromyelitis optica spectrum disorders: Results of an international survey

BACKGROUND

Currently, there is no evidence-based definition of attacks in neuromyelitis optica spectrum disorders (NMOSD). However, to allow their stringent use as valid endpoints, recent phase III trials in NMOSD defined criteria and adjudication of these events in context of these trials. The objective of this study was to investigate diagnostic procedures currently used in routine adjudication of suspected attacks in NMOSD, and to assess whether the standardized attack-criteria from two pivotal trials may be feasible in routine clinical care.

METHODS

Four global clinical networks were surveyed using an online questionnaire: NEMOS (Neuromyelitis Optica Study Group), IMSVISUAL (International Multiple Sclerosis Visual System Consortium), GJCF-ICC (Guthy Jackson Charitable Foundation-International Clinical Consortium) and NOMADMUS (Devic's neuromyelitis optica and related neurological disorders study group).

RESULTS

Seventy-eight responses were received from September 2018 to February 2019. Median annual number of patients seen with suspected attacks was 10 (range 2-130). Immediate access to MRI was reported by 59.0% of all participants and the majority performs an MRI for new patients with a myelitis, optic neuritis or other symptoms. In patients with established NMOSD diagnosis presenting during routine clinical visits only 10.5% or 9.2% always perform a brain or spinal cord MRI, respectively. Digital records of patients' visits are kept by 98.7% of all participants and 88.5% have direct access to case history. An expert neurological examination is performed for 94.9% of participants reported to perform an expert neurological examination in patients with acute attacs, while only 30.8% seem to perform the assessments according to the Neurostatus-Expanded Disability Status Scale (EDSS) definitions.. The Sakura Star study criteria which are based solely on clinical assessment could be feasible in routine care, provided that more centers use the Neurostatus-EDSS, while only 9% of participants fulfill all requirements for adjudication of the N-Momentum study criteria.

CONCLUSIONS

The high percentage of centers using digital records is encouraging. However, routine adjudication of clinical events in NMOSD seems highly heterogeneous. MRI is the mainstay in the majority of queried centers, but its immediate availability is limited. Only a minority of centers are equipped for trial-grade classification of attacks, if this is not solely clinically based. Thus, standard and feasible guidelines for attack adjudication are urgently needed to standardize routine care, optimize future clinical trials and allow studying long-term safety and efficacy of newly approved drugs in phase IV trials.

Complement factor I deficiency: A potentially treatable cause of fulminant cerebral inflammation

Objective

To raise awareness of complement factor I (CFI) deficiency as a potentially treatable cause of severe cerebral inflammation.

Methods

Case report with neuroradiology, neuropathology, and functional data describing the mutation with review of literature.

Results

We present a case of acute, fulminant, destructive cerebral edema in a previously well 11-year-old, demonstrating massive activation of complement pathways on neuropathology and compound heterozygote status for 2 pathogenic mutations in CFI which result in normal levels but completely abrogate function.

Conclusions

Our case adds to a very small number of extant reports of this phenomenon associated with a spectrum of inflammatory histopathologies including hemorrhagic leukoencephalopathy and clinical presentations resembling severe acute disseminated encephalomyelitis. CFI deficiency can result in uncontrolled activation of the complement pathways in the brain resulting in devastating cerebral inflammation. The deficit is latent, but the catastrophic dysregulation of the complement system may be the result of a C3 acute phase response. Diagnoses to date have been retrospective. Diagnosis requires a high index of suspicion and clinician awareness of the limitations of first-line clinical tests of complement activity and activation. Simple measurement of circulating CFI levels, as here, may fail to diagnose functional deficiency with absent CFI activity. These diagnostic challenges may mean that the CFI deficiency is being systematically under-recognized as a cause of fulminant cerebral inflammation. Complement inhibitory therapies (such as eculizumab) offer new potential treatment, underlining the importance of prompt recognition, and real-time whole exome sequencing may play an important future role.

Isolated Area Postrema Syndrome Presenting as Intractable Nausea and Vomiting

Neuromyelitis optica (NMO) is a disease of central nervous system, characterized by demyelination and axonal damage mostly involving optic nerves and spinal cord. Usually these patients present with symptoms related to optic neuritis or myelitis with a typical relapsing course. Some patients present with less common symptoms involving brain stem like nausea and vomiting, especially those involving area postrema (AP) located in dorsal medulla. International panel for NMO diagnosis revised criteria in 2015 and came up with a unifying term NMO spectrum disorders (NMOSD) instead of NMO. Patients with NMO having AP involvement are grouped under area postrema syndrome (APS). Usually patients with AP symptoms also have neurological symptoms upon presentation. Here we present a rare case of an NMO who presented with isolated APS with no other neurological symptoms.

Binding patterns and functional properties of human antibodies to AQP4 and MOG on murine optic nerve and retina

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune-inflammatory CNS disease affecting spinal cord and optic nerves, mediated by autoantibodies against aquaporin-4 (AQP4) and myelin-oligodendrocyte-glycoprotein (MOG). Effects of those immunoglobulins (Ig) on retina and optic nerve are incompletely understood. We investigated AQP4-IgG and MOG-IgG sera on retina and optic nerve ex vivo and in 2D2 mice, which harbor a transgenic MOG-specific T-cell receptor. Some sera reacted with murine retina and optic nerve showing distinct binding patterns, suggesting different epitopes being targeted in both subgroups. Transfer of total IgG from a MOG-IgG positive patient to 2D2 mice did neither enhance disability nor induce functional or histological alterations in the retina.

[Neuromyelitis optica and neuromyelitis optica spectrum disorders]

The review is devoted to up-to-date data on epidemiology, aspects of the pathogenesis of neuromyelitis optica (NMO) and neuromyelitis optica spectrum disorders (NMOSD). The authors consider a role of myelin oligodendrocyte glycoprotein immunoglobulin G (MOG-IgG) in the syndromes phenotypically similar to NMO and NMOSD. Special attention is drawn to the methods of MOG-IgG antibodies detection and indications for testing. The approaches and management for treatment and prevention of NMO relapses, risks of complications during pregnancy and immediately after delivery, as well as methods for their prevention and treatment, are described.

Autoimmune encephalitis management: MS centers and beyond

Traditionally, multiple sclerosis (MS) specialists have been the go-to providers for managing certain treatable non-demyelinating inflammatory or autoimmune central nervous system (CNS) disorders. The advent of increased incidence (mostly due to improved recognition) prompts the question: who should be managing autoimmune encephalitis? These patients are generally first encountered in the hospital, as well as general neurology and subspecialty clinics, such as epilepsy. Autoimmune neurology is a specialty which gives focus to evaluation and treatment of patients with autoimmune encephalitis, among other disorders, and trains neurologists accordingly. Some of those experts are dual trained in both MS and non-MS inflammatory/autoimmune CNS disorders. Many other autoimmune specialists are trained in non-MS care, such as hospital neurology, movement disorders, and epilepsy. General and other subspecialty providers increasingly find the need to be versed in management of autoimmune encephalitis.

The clinical profile of NMOSD in Australia and New Zealand

Neuromyelitis optica spectrum disorders (NMOSD) are an inflammation of the central nervous system associated with autoantibodies to aquaporin-4. We have undertaken a clinic-based survey of NMOSD in the Australia and New Zealand populations with the aim of characterising the clinical features and establishing the value of recently revised diagnostic criteria. Cases of possible NMOSD and age and sex-matched controls with multiple sclerosis (MS) were referred from centres across Australia and New Zealand. Cases were classified as NMOSD if they met the 2015 IPND criteria and remained as suspected NMOSD if they did not. Clinical and paraclinical data were compared across the three groups. NMOSD was confirmed in 75 cases and 89 had suspected NMOSD. There were 101 controls with MS. Age at onset, relapse rates and EDSS scores were significantly higher in NMOSD than in MS. Lesions and symptoms referable to the optic nerve were more common in NMOSD whereas brainstem, cerebellar and cerebral lesions were more common in MS. Longitudinally extensive spinal cord lesions were seen in 48/71 (68%) of cases with NMOSD. Elevations of CSF, white cell count and protein were more common in NMOSD. We have confirmed a clinical pattern of NMOSD that has been seen in several geographical regions. We have demonstrated the clinical utility of the current diagnostic criteria. Distinct patterns of disease are evident in NMOSD and MS, but there remains a large number of patients with NMOSD-like features who do not meet the current diagnostic criteria for NMOSD and remain a diagnostic challenge.

Pediatric NMOSD: A Review and Position Statement on Approach to Work-Up and Diagnosis

Neuromyelitis Optica Spectrum Disorder (NMOSD) is an inflammatory demyelinating disease of the central nervous system (CNS) primarily affecting the optic nerves and spinal cord, but also involving other regions of the CNS including the area postrema, periaqueductal gray matter, and hypothalamus. Knowledge related to pediatric manifestations of NMOSD has grown in recent years, particularly in light of newer information regarding the importance of not only antibodies to aquaporin 4 (AQP4-IgG) but also myelin oligodendrocyte glycoprotein (MOG-IgG) in children manifesting clinically with this syndrome. In this review, we describe the current state of the knowledge related to clinical manifestations, diagnosis, and chronic therapies for children with NMOSD, with emphasis on literature that has been published in the last 5 years. Following the review, we propose recommendations for the assessment/follow up clinical care, and treatment of this population.

Monoclonal Antibody Therapies for Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorder

Considerable progress has been made in treatments for multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) over the last several decades. However, the present treatments do not show satisfactory efficacy or safety in a considerable proportion of patients, who experience relapse or disability progression despite receiving treatment and suffer from side effects, which can be severe. Improvements in the understanding of the pathophysiologies of MS and NMOSD have led to numerous therapeutic approaches being proposed and developed. Monoclonal antibodies (mAbs) are receiving increasing attention because of their specificity of action and likelihood of high efficacy with fewer side effects. Many mAbs have been evaluated, and some have been approved for MS or NMOSD treatment. This article reviews the use of mAbs for treating MS and NMOSD, including summarizing their mechanisms of action, efficacy, and safety profiles.

Cytomegalovirus Infection in an Adult Patient With Neuromyelitis Optica and Acute Hemorrhagic Rectal Ulcer: Case Report and Literature Review

Background: Previous infectious or inflammatory events may be involved in the pathogenesis of neuromyelitis optica (NMO), potentially by triggering an autoimmune response. Cytomegalovirus (CMV)-related NMO (CMV-NMO) is rarely reported. Acute hemorrhagic rectal ulcer (AHRU) is a rare disease with a largely unknown pathogenesis. Herein, we reported a co-NMO and AHRU case associated with CMV infection. In addition, we review previously reported cases of CMV-NMO and CMV-AHRU. Case presentation: A 40-year-old female diagnosed with aquaporin4 (AQP4)-IgG⁺ NMO and a poor response to high-dose intravenous methylprednisolone and immunoglobulin, followed by three rounds of plasma exchange was transferred to Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China. She developed repeated acute lower gastrointestinal hemorrhage from the third day of admission. Abdominal computed tomography angiography (CTA) and interventional angiography did not detect any bleeding vessel. Bedside colonoscopy revealed a large ulcer-like lesion at 10 cm above the anus. Rectal biopsy pathology confirmed a CMV infection on day 23 post-admission, and cerebrospinal fluid (CSF) pathogen gene sequencing detected CMV gene copies on day 25 post-admission. After 2 weeks of treatment with ganciclovir and sodium phosphinate, the patient's lower gastrointestinal bleeding stopped, and her limb muscle strength and visual acuity gradually improved. After 4 weeks of antiviral therapy, colonoscopy showed that the intestinal wall of the original lesion was smooth. Hematoxylin and eosin (HE) staining and immunohistochemistry (IHC) of a biopsy specimen was negative for CMV, her right eye vision was normal, and limb muscle strength had recovered. Serum AQP4-IgG was negative, and lesions on brain magnetic resonance imaging (MRI) manifested shrinkage. Conclusions: The benefits of antiviral therapy remain unclear; however, clinicians should be aware of the possibility of CMV-related NMO, if NMO was refractory to high-dose intravenous methylprednisolone, immunoglobulin, and plasma exchange. Moreover, clinicians should consider the possibility of CMV-related AHRU when recurrent acute lower gastrointestinal bleeding occurs in a patient.

Clinical Characteristics and Treatment of MOG-IgG-Associated Optic Neuritis

PURPOSE OF REVIEW

Antibodies against myelin oligodendrocyte glycoprotein (MOG) are associated with a unique acquired central nervous system demyelinating disease-termed MOG-IgG-associated disorder (MOGAD)-which has a variety of clinical manifestations, including optic neuritis, transverse myelitis, acute disseminating encephalomyelitis, and brainstem encephalitis. In this review, we summarize the current knowledge of the clinical characteristics, neuroimaging, treatments, and outcomes of MOGAD, with a focus on optic neuritis.

RECENT FINDINGS

The recent development of a reproducible, live cell-based assay for MOG-IgG, has improved our ability to identify and study this disease. Based on contemporary studies, it has become increasingly evident that MOGAD is distinct from multiple sclerosis and aquaporin-4-positive neuromyelitis optica spectrum disorder with different clinical features and treatment outcomes. There is now sufficient evidence to separate MOGAD from other inflammatory central nervous system demyelinating disorders, which will allow focused research on understanding the pathophysiology of the disease. Prospective treatment trials are needed to determine the best course of treatment, and until then, treatment plans must be individualized to the clinical manifestations and severity of disease.

Neuromyelitis optica spectrum disorders with unevenly clustered attack occurrence

Objective

The aim of this study was to elucidate the characteristics of clinical attacks in neuromyelitis optica spectrum disorders (NMOSDs) with positive serum anti-aquaporin-4 antibody. Both the timing and sequential pattern of clinical types were analyzed.

Methods

A total of 69 patients with NMOSD were enrolled in this study, all of whom were treated at a single university hospital. All data regarding the clinical attacks (including types and date) together with other clinical information were collected.

Results

Analysis of clinical attacks from the enrolled patients showed that there were 2 distributional patterns of attack occurrence in each patient: (1) “clustered” occurrences, which occurred within 12 months from the previous attack, and (2) “nonclustered” intermittent occurrences, which occurred ≥12 months after the previous attack. These occurrences were regardless of the duration from the onset. During the “clustered” period, clinical attacks were more likely to show a similar clinical manifestation, such as optic neuritis or myelitis. After entering the “nonclustered” intermittent period, the relapses were of random clinical type, regardless of the previous clinical manifestation.

Conclusions

Patients with NMOSD showed mixed periods of “clustered” occurrence with frequent attacks presenting with similar manifestations and “nonclustered” intermittent periods with sparse relapses. Approximately half of the relapses occurred during the “clustered” period within 12 months of the last clinical attack. Clinicians should pay special attention to whether the patients are presently in the “clustered” or “nonclustered” period to decide optimal relapse-preventive strategies.

Will biological agents supplant systemic glucocorticoids as the first-line treatment for thyroid-associated ophthalmopathy?

In this article, the two authors present their opposing points of view concerning the likelihood that glucocorticoids will be replaced by newly developed biological agents in the treatment of active, moderate-to-severe thyroid-associated ophthalmopathy (TAO). TAO is a vexing, disfiguring and potentially blinding autoimmune manifestation of thyroid autoimmunity. One author expresses the opinion that steroids are nonspecific, frequently fail to improve the disease and can cause sometimes serious side effects. He suggests that glucocorticoids should be replaced as soon as possible by more specific and safer drugs, once they become available. The most promising of these are biological agents. The other author argues that glucocorticoids are proven effective and are unlikely to be replaced by biologicals. He reasons that while they may not uniformly result in optimal benefit, they have been proven effective in many reports. He remains open minded about alternative therapies such as biologicals but remains skeptical that they will replace steroids as the first-line therapy for active, moderate-to-severe TAO without head-to-head comparative clinical trials demonstrating superiority. Despite these very different points of view, both authors are optimistic about the availability of improved medical therapies for TAO, either as single agents or in combination. Further, both agree that better treatment options are needed to improve the care of our patients with active moderate-to-severe TAO.

Validation of claims-based diagnoses of adult and pediatric neuromyelitis optica spectrum disorder and variations in diagnostic evaluation and treatment initiation

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is a rare demyelinating disease in need of more studies to determine effective treatment regimens. The rarity of the disorder, however, makes large randomized-controlled trials challenging. Validation of the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) code for NMO could facilitate the use of large healthcare claims data for future research. We aimed 1) to determine the positive predictive value (PPV) of the ICD-9-CM code for NMO as well as evaluate case-finding algorithms for the identification of patients with NMO/NMOSD and 2) to compare the evaluation of and treatment for pediatric versus adult patients.

METHODS

This was a multicenter retrospective cohort study of patients with ≥ 1 ICD-9 code for NMO seen at 3 pediatric and 2 adult United States medical centers from 2001-2016. Using a standardized data entry form, pediatric and adult neurologists and rheumatologists reviewed patients' medical records to determine whether patients fulfilled the 2006 criteria for NMO and/or the 2015 criteria for NMOSD in order to determine the positive predictive value (PPV) for the ICD-9-CM code. Demographic and clinical information was abstracted from patient medical records to ascertain variables then evaluated in case-based finding algorithms for further identification of patients with true NMO/NMOSD. We also evaluated differences in clinical characteristics between pediatric and adult patients using chi-squared or Fisher's exact tests, as appropriate, to assess for treatment variation.

RESULTS

A single code for NMO had a PPV of 47% across all sites, with significant site variation (0-77%). The best case-finding algorithm included at least 5 codes as well as a documented hospitalization (PPV = =90% for children and PPV = 92% for adults). Children were more likely to be evaluated by a rheumatologist or ophthalmologist, undergo magnetic resonance imaging of the orbits, and receive immunosuppressive and biologic agents than their adult counterparts. Rituximab was administered similarly among the two groups.

CONCLUSION

The ICD-9 code for neuromyelitis optica (NMO) is inaccurate for identification of NMO/NMOSD. Using case-finding algorithms increases the PPV. The initial diagnostic evaluation and treatment of NMOSD differs significantly between children and adults.

Experimental animal models of aquaporin-4-IgG-seropositive neuromyelitis optica spectrum disorders: progress and shortcomings

Neuromyelitis optica spectrum disorders (NMOSD) is a heterogeneous group of neuroinflammatory conditions associated with demyelination primarily in spinal cord and optic nerve, and to a lesser extent in brain. Most NMOSD patients are seropositive for IgG autoantibodies against aquaporin-4 (AQP4-IgG), the principal water channel in astrocytes. There has been interest in establishing experimental animal models of seropositive NMOSD (herein referred to as NMO) in order to elucidate NMO pathogenesis mechanisms and to evaluate drug candidates. An important outcome of early NMO animal models was evidence for a pathogenic role of AQP4-IgG. However, available animal models of NMO, based largely on passive transfer to rodents of AQP4-IgG or transfer of AQP4-sensitized T cells, often together with pro-inflammatory maneuvers, only partially recapitulate the clinical and pathological features of human NMO, and are inherently biased toward humoral or cellular immune mechanisms. This review summarizes current progress and shortcomings in experimental animal models of seropositive NMOSD, and opines on the import of advancing animal models.

Neuromyelitis optica spectrum disorders in Arabian Gulf (NMOAG); establishment and initial characterization of a patient registry

OBJECTIVE

To describe the clinical and radiological characteristics of neuromyelitis optica spectrum disorders (NMOSD) patients from the Arabian Gulf relative to anti-aquaporin 4 antibody serostatus.

METHODS

Retrospective multicentre study of hospital records of patients diagnosed with NMOSD based on 2015 International Panel on NMOSD Diagnosis (IPND) consensus criteria.

RESULTS

One hundred forty four patients were evaluated, 64.3% were anti-AQP4 antibody positive. Mean age at onset and disease duration were 31±12 and 7 ± 6 years respectively. Patients were predominantly female (4.7:1). Overall; relapsing course (80%) was more common than monophasic (20%). Optic neuritis was the most frequent presentation (48.6%), regardless of serostatus. The proportion of patients (54.3%) with visual acuity of ≤ 0.1 was higher in the seropositive group (p = 0.018). Primary presenting symptoms of transverse myelitis (TM) were observed in 29% of patients, and were the most significant correlate of hospitalization (p<0.001). Relative to anti-APQ4 serostatus, there were no significant differences in terms of age of onset, course, relapse rates or efficacy outcomes except for oligoclonal bands (OCB), which were more often present in seronegative patients (40% vs.22.5%; p = 0.054). Irrespective of serostatus, several disease modifying therapies were instituted including steroids or immunosuppressives, mostly, rituximab and azathioprine in the cohort irrespective of serostatus. The use of rituximab resulted in reduction in disease activity.

CONCLUSION

This is the first descriptive NMOSD cohort in the Arabian Gulf region. Seropositive patients were more prevalent with female predominance. Relapsing course was more common than monophasic. However, anti-AQP4 serostatus did not impact disease duration, relapse rate or therapeutic effectiveness. These findings offer new insights into natural history of NMOSD in patients of the Arabian Gulf and allow comparison with patient populations in different World regions.

Inebilizumab for the treatment of neuromyelitis optica spectrum disorder (N-MOmentum): a double-blind, randomised placebo-controlled phase 2/3 trial

BACKGROUND

No approved therapies exist for neuromyelitis optica spectrum disorder (NMOSD), a rare, relapsing, autoimmune, inflammatory disease of the CNS that causes blindness and paralysis. We aimed to assess the efficacy and safety of inebilizumab, an anti-CD19, B cell-depleting antibody, in reducing the risk of attacks and disability in NMOSD.

METHODS

We did a multicentre, double-blind, randomised placebo-controlled phase 2/3 study at 99 outpatient specialty clinics or hospitals in 25 countries. Eligible participants were adults (≥18 years old) with a diagnosis of NMOSD, an Expanded Disability Status Scale score of 8·0 or less, and a history of at least one attack requiring rescue therapy in the year before screening or at least two attacks requiring rescue therapy in the 2 years before screening. Participants were randomly allocated (3:1) to 300 mg intravenous inebilizumab or placebo with a central interactive voice response system or interactive web response system and permuted block randomisation. Inebilizumab or placebo was administered on days 1 and 15. Participants, investigators, and all clinical staff were masked to the treatments, and inebilizumab and placebo were indistinguishable in appearance. The primary endpoint was time to onset of an NMOSD attack, as determined by the adjudication committee. Efficacy endpoints were assessed in all randomly allocated patients who received at least one dose of study intervention, and safety endpoints were assessed in the as-treated population. The study is registered with ClinicalTrials.gov, number NCT02200770.

FINDINGS

Between Jan 6, 2015, and Sept 24, 2018, 230 participants were randomly assigned to treatment and dosed, with 174 participants receiving inebilizumab and 56 receiving placebo. The randomised controlled period was stopped before complete enrolment, as recommended by the independent data-monitoring committee, because of a clear demonstration of efficacy. 21 (12%) of 174 participants receiving inebilizumab had an attack versus 22 (39%) of 56 participants receiving placebo (hazard ratio 0·272 [95% CI 0·150-0·496]; p<0·0001). Adverse events occurred in 125 (72%) of 174 participants receiving inebilizumab and 41 (73%) of 56 participants receiving placebo. Serious adverse events occurred in eight (5%) of 174 participants receiving inebilizumab and five (9%) of 56 participants receiving placebo.

INTERPRETATION

Compared with placebo, inebilizumab reduced the risk of an NMOSD attack. Inebilizumab has potential application as an evidence-based treatment for patients with NMOSD.

FUNDING

MedImmune and Viela Bio.

Autologous nonmyeloablative hematopoietic stem cell transplantation for neuromyelitis optica

OBJECTIVE

To determine if autologous nonmyeloablative hematopoietic stem cell transplantation (HSCT) could be a salvage therapy for neuromyelitis optica spectrum disorder (NMOSD).

METHODS

Thirteen patients were enrolled in a prospective open-label cohort study (11 NMOSD aquaporin-4-immunoglobulin G [AQP4-IgG]-positive, 1 NMOSD without AQP4, and 1 NMOSD AQP4-IgG-positive with neuropsychiatric systemic lupus erythematosus [SLE]). Following stem cell mobilization with cyclophosphamide (2 g/m²) and filgrastim, patients were treated with cyclophosphamide (200 mg/kg) divided as 50 mg/kg IV on day -5 to day -2, rATG (thymoglobulin) given IV at 0.5 mg/kg on day -5, 1 mg/kg on day -4, and 1.5 mg/kg on days -3, -2, and -1 (total dose 6 mg/kg), and rituximab 500 mg IV on days -6 and +1. Unselected peripheral blood stem cells were infused on day 0. AQP4-IgG antibody status was determined by Clinical Laboratory Improvement Amendments-validated ELISA or flow cytometry assays. Cell-killing activity was measured using a flow cytometry-based complement assay.

RESULTS

Median follow-up was 57 months. The patient with coexistent SLE died of complications of active lupus 10 months after HSCT. For the 12 patients with NMOSD without other active coexisting autoimmune diseases, 11 patients are more than 5 years post-transplant, and 80% are relapse-free off all immunosuppression (p < 0.001). At 1 and 5 years after HSCT, Expanded Disability Status Scale score improved from a baseline mean of 4.4 to 3.3 (p < 0.01) at 5 years. The Neurologic Rating Scale score improved after HSCT from a baseline mean of 69.5 to 85.7 at 5 years (p < 0.01). The Short Form-36 health survey for quality of life total score improved from mean 34.2 to 62.1 (p = 0.001) at 5 years. In the 11 patients whose baseline AQP4-IgG serostatus was positive, 9 patients became seronegative by the immunofluorescence or cell-binding assays available at the time; complement activating and cell-killing ability of patient serum was switched off in 6 of 7 patients with before and after HSCT testing. Two patients remained AQP4-IgG-seropositive (with persistent complement activating and cell-killing ability) and relapsed within 2 years of HSCT. No patient with seronegative conversion relapsed.

CONCLUSION

Prolonged drug-free remission with AQP4-IgG seroconversion to negative following nonmyeloablative autologous HSCT warrants further investigation.

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.

Optic neuritis in the era of biomarkers

The Optic Neuritis Treatment Trial, a landmark study completed in 1991, stratified the risk of multiple sclerosis in patients with optic neuritis. Since that time, unique biomarkers for optic neuritis have been found. The antibody against aquaporin-4 (AQP4)-immunoglobulin G (IgG) discovered in 2004 was found to be both the pathologic cause and a reliable biomarker for neuromyelitis optica spectrum disorders. This finding enabled an expanded definition of the phenotype of neuromyelitis optica spectrum disorder and improved treatment of the disease. Subsequently, myelin oligodendrocyte glycoprotein (MOG) IgG was recognized to be a marker for MOG-IgG-associated disorder, a central demyelinating disease characterized by recurrent optic neuritis, prominent disk edema, and perineural optic nerve enhancement on magnetic resonance imaging. Most multiple sclerosis disease-modifying agents are ineffective for AQP4-IgG-positive neuromyelitis optica spectrum disorder and MOG-IgG-associated disorder. Because there are crucial differences in treatment and prognosis between multiple sclerosis, AQP4-IgG-positive neuromyelitis optica spectrum disorder, and MOG-IgG-associated disorder, ophthalmologists should be aware of these new biomarkers of optic neuritis and incorporate their testing in all patients with atypical optic neuritis.

Therapeutic Modulation of the Complement Cascade in Stroke

Stroke is a leading cause of death and disability worldwide and an increasing number of ischemic stroke patients are undergoing pharmacological and mechanical reperfusion. Both human and experimental models of reperfused ischemic stroke have implicated the complement cascade in secondary tissue injury. Most data point to the lectin and alternative pathways as key to activation, and C3a and C5a binding of their receptors as critical effectors of injury. During periods of thrombolysis use to treat stroke, acute experimental complement cascade blockade has been found to rescue tissue and improves functional outcome. Blockade of the complement cascade during the period of tissue reorganization, repair, and recovery is by contrast not helpful and in fact is likely to be deleterious with emerging data suggesting downstream upregulation of the cascade might even facilitate recovery. Successful clinical translation will require the right clinical setting and pharmacologic strategies that are capable of targeting the key effectors early while not inhibiting delayed repair. Early reports in a variety of disease states suggest that such pharmacologic strategies appear to have a favorable risk profile and offer substantial hope for patients.

Differential Diagnosis of Pediatric Multiple Sclerosis

The differential diagnosis of pediatric multiple sclerosis (MS) can be broad and pose diagnostic challenges, particularly at initial presentation. Among demyelinating entities, neuromyelitis optica spectrum disorders (NMOSD), myelin oligodendrocyte glycoprotein antibodies (MOG-ab) associated disorders, and acute disseminated encephalomyelitis (ADEM) are now well-known as unique disease processes and yet continue to overlap with MS in regards to clinical presentation and imaging. In non-inflammatory entities, such as metabolic disorders and leukodystrophies, an erroneous diagnosis of MS can be made even while applying appropriate diagnostic criteria. Knowing the epidemiology, typical clinical presentation, diagnostic criteria, and ancillary test results in each disease, can aid in making the correct diagnosis by contrasting these features with those of pediatric MS. Determining the correct diagnosis early, allows for efficient and effective treatment as well as appropriate prognostication.