Eculizumab in Aquaporin-4-Positive Neuromyelitis Optica Spectrum Disorder

Eculizumab Use in Neuromyelitis Optica Spectrum Disorders: Routine Clinical Care Data From a European Cohort

BACKGROUND AND OBJECTIVES

Attack prevention is crucial in managing neuromyelitis optica spectrum disorders (NMOSDs). Eculizumab (ECU), an inhibitor of the terminal complement cascade, was highly effective in preventing attacks in a phase III trial of aquaporin-4 (AQP4)-IgG seropositive(+) NMOSDs. In this article, we evaluated effectiveness and safety of ECU in routine clinical care.

METHODS

We retrospectively evaluated patients with AQP4-IgG+ NMOSD treated with ECU between December 2014 and April 2022 at 20 German and 1 Austrian university center(s) of the Neuromyelitis Optica Study Group (NEMOS) by chart review. Primary outcomes were effectiveness (assessed using annualized attack rate [AAR], MRI activity, and disability changes [Expanded Disability Status Scale {EDSS}]) and safety (including adverse events, mortality, and attacks after meningococcal vaccinations), analyzed by descriptive statistics.

RESULTS

Fifty-two patients (87% female, age 55.0 ± 16.3 years) received ECU for 16.2 (interquartile range [IQR] 9.6 - 21.7) months. Forty-five patients (87%) received meningococcal vaccination before starting ECU, 9 with concomitant oral prednisone and 36 without. Seven of the latter (19%) experienced attacks shortly after vaccination (median: 9 days, IQR 6-10 days). No postvaccinal attack occurred in the 9 patients vaccinated while on oral prednisone before starting ECU and in 25 (re-)vaccinated while on ECU. During ECU therapy, 88% of patients were attack-free. The median AAR decreased from 1.0 (range 0-4) in the 2 years preceding ECU to 0 (range 0-0.8; p < 0.001). The EDSS score from start to the last follow-up was stable (median 6.0), and the proportion of patients with new T2-enhancing or gadolinium-enhancing MRI lesions in the brain and spinal cord decreased. Seven patients (13%) experienced serious infections. Five patients (10%; median age 53.7 years) died on ECU treatment (1 from myocardial infarction, 1 from ileus with secondary sepsis, and 3 from systemic infection, including 1 meningococcal sepsis), 4 were older than 60 years and severely disabled at ECU treatment start (EDSS score ≥ 7). The overall discontinuation rate was 19%.

DISCUSSION

Eculizumab proved to be effective in preventing NMOSD attacks. An increased risk of attacks after meningococcal vaccination before ECU start and potentially fatal systemic infections during ECU-particularly in patients with comorbidities-must be considered. Further research is necessary to explore optimal timing for meningococcal vaccinations.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence that eculizumab reduces annualized attack rates and new MRI lesions in AQP4-IgG+ patients with NMOSD.

Clinical practice guidelines for multiple sclerosis, neuromyelitis optica spectrum disorder, and myelin oligodendrocyte glycoprotein antibody-associated disease 2023 in Japan

BACKGROUND

The previous Japanese clinical practice guidelines for multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) were published in 2017. Recently, for the first time in 6 years, the MS and NMOSD guideline development committee revised the Japanese guidelines for MS, NMOSD, and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD).

METHODS

The committee utilized the Grading of Recommendations Assessment, Development, and Evaluation system based on the "Minds Handbook for Clinical Practice Guideline Development 2020 Ver. 3.0″ with a focus on clinical questions (CQs). The committee also discussed clinical issues other than CQs, categorizing them as a question-and-answer (Q&A) section, including "issues on which experts' opinions agree to a certain extent" and "issues that are important but not included in the CQ".

RESULTS

The committee identified 3, 1, and 1 key CQs related to MS, NMOSD, and MOGAD, respectively, and presented recommendations. A Q&A session regarding disease-modifying therapies and relapse prevention therapies for MS, NMOSD, and MOGAD was conducted. The revised guidelines were published in September 2023.

CONCLUSIONS

The Japanese guidelines for clinical practice on MS, NMOSD, and MOGAD were updated. Treatment strategies for MS, NMOSD, and MOGAD are changing, and these updated guidelines may assist with treatment decisions for these diseases in clinical practice.

NMOSD and MOGAD: an evolving disease spectrum

Neuromyelitis optica (NMO) spectrum disorder (NMOSD) is a relapsing inflammatory disease of the CNS, characterized by the presence of serum aquaporin 4 (AQP4) autoantibodies (AQP4-IgGs) and core clinical manifestations such as optic neuritis, myelitis, and brain or brainstem syndromes. Some people exhibit clinical characteristics of NMOSD but test negative for AQP4-IgG, and a subset of these individuals are now recognized to have serum autoantibodies against myelin oligodendrocyte glycoprotein (MOG) - a condition termed MOG antibody-associated disease (MOGAD). Therefore, the concept of NMOSD is changing, with a disease spectrum emerging that includes AQP4-IgG-seropositive NMOSD, MOGAD and double-seronegative NMOSD. MOGAD shares features with NMOSD, including optic neuritis and myelitis, but has distinct pathophysiology, clinical profiles, neuroimaging findings (including acute disseminated encephalomyelitis and/or cortical encephalitis) and biomarkers. AQP4-IgG-seronegative NMOSD seems to be a heterogeneous condition and requires further study. MOGAD can manifest as either a monophasic or a relapsing disease, whereas NMOSD is usually relapsing. This Review summarizes the history and current concepts of NMOSD and MOGAD, comparing epidemiology, clinical features, neuroimaging, pathology and immunology. In addition, we discuss new monoclonal antibody therapies for AQP4-IgG-seropositive NMOSD that target complement, B cells or IL-6 receptors, which might be applied to MOGAD in the near future.

The interaction of innate immune and adaptive immune system

The innate immune system serves as the body's first line of defense, utilizing pattern recognition receptors like Toll-like receptors to detect pathogens and initiate rapid response mechanisms. Following this initial response, adaptive immunity provides highly specific and sustained killing of pathogens via B cells, T cells, and antibodies. Traditionally, it has been assumed that innate immunity activates adaptive immunity; however, recent studies have revealed more complex interactions. This review provides a detailed dissection of the composition and function of the innate and adaptive immune systems, emphasizing their synergistic roles in physiological and pathological contexts, providing new insights into the link between these two forms of immunity. Precise regulation of both immune systems at the same time is more beneficial in the fight against immune-related diseases, for example, the cGAS-STING pathway has been found to play an important role in infections and cancers. In addition, this paper summarizes the challenges and future directions in the field of immunity, including the latest single-cell sequencing technologies, CAR-T cell therapy, and immune checkpoint inhibitors. By summarizing these developments, this review aims to enhance our understanding of the complexity interactions between innate and adaptive immunity and provides new perspectives in understanding the immune system.

Strategies to improve autoimmune neurological diseases treatment

There is a need to improve therapies in autoimmune neurologic conditions. Yet which strategic objectives are required, what are the barriers that stand before reaching them, and what are the options to address them? This article tries to summarize these objectives and their respective barriers. It discusses the difficulties in identifying molecular targets, biomarker-defined subgroups, the merits of upstream and downstream-targeted therapies, the need to develop autoreactivity-specific treatments in contrast to cell-type specific therapies, and the "evidence-bottleneck". Its focus is on autoantigen-specific autoimmunopathies in neurology. It also discusses the role of B- and T-cells in autoimmune neurology and how these can be exploited therapeutically. Finally, it argues for improved training of present and future neuroimmunologists.

Complement system activation: bridging physiology, pathophysiology, and therapy

The complement system is a set of over 50 proteins that constitutes an essential part of the innate immune system. Complement system activation involves an organized proteolytic cascade. Overactivation of complement system activation is the main pathogenic mechanism of several diseases and contributes to the manifestations of many other conditions. This review describes the normal complement system and the role for complement dysregulation in critical illnesses, notably sepsis and acute respiratory distress syndrome. Complement activation is involved in the immune system response to pathogens but, when excessive, can contribute to tissue damage, runaway inflammation, and capillary leakage syndrome. Complement overactivation may play a key role in severe forms of coronavirus disease 2019 (COVID-19). Two diseases whose manifestations are mainly caused by complement overactivation, namely, atypical hemolytic and uremic syndrome (aHUS) and myasthenia gravis, are discussed. A diagnostic algorithm for aHUS is provided. Early complement-inhibiting therapy has been proven effective. When renal transplantation is required, complement-inhibiting drugs can be used prophylactically to prevent aHUS recurrence. Similarly, acetylcholine-receptor autoantibody-positive generalized myasthenia gravis involves complement system overactivation and responds to complement inhibition. The two main complement inhibitors used in to date routine are eculizumab and ravulizumab. The main adverse event is Neisseria infection, which is rare and preventable, but can be fatal. The complement system is crucial to health but, when overactivated, can cause or contribute to disease. Effective complement inhibitors are now available, although additional data are required to determine optimal regimens. Further research is also needed to better understand the complement system, develop advanced diagnostic tools, and identify markers that allow the personalization of treatment strategies.

The Role of Chimeric Antigen Receptor T-Cell Therapy in Immune-Mediated Neurological Diseases

Despite the use of 'high efficacy' disease-modifying therapies, disease activity and clinical progression of different immune-mediated neurological diseases continue for some patients, resulting in accumulating disability, deteriorating social and mental health, and high economic cost to patients and society. Although autologous hematopoietic stem cell transplant is an effective treatment modality, it is an intensive chemotherapy-based therapy with a range of short- and long-term side-effects. Chimeric antigen receptor T-cell therapy (CAR-T) has revolutionized the treatment of B-cell and other hematological malignancies, conferring long-term remission for otherwise refractory diseases. However, the toxicity of this treatment, particularly cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome, and the complexity of production necessitate the need for a high level of specialization at treating centers. Early-phase trials of CAR-T therapies in immune-mediated B cell driven conditions, such as systemic lupus erythematosus, neuromyelitis optica spectrum disorder and myasthenia gravis, have shown dramatic clinical response with few adverse events. Based on the common physiopathology, CAR-T therapy in other immune-mediated neurological disease, including multiple sclerosis, chronic inflammatory polyradiculopathy, autoimmune encephalitis, and stiff person syndrome, might be an effective option for patients, avoiding the need for long-term immunosuppressant medications. It may prove to be a more selective immunoablative approach than autologous hematopoietic stem cell transplant, with potentially increased efficacy and lower adverse events. In this review, we present the state of the art and future directions of the use of CAR-T in such conditions. ANN NEUROL 2024;96:441-452.

The efficacy and safety of eculizumab in patients and the role of C5 polymorphisms

Eculizumab is an orphan drug with indications for extremely rare autoimmune disorders. It is primarily prescribed for use in patients with paroxysmal nocturnal hemoglobinuria and atypical hemolytic uremic syndrome; but is also highly effective in the treatment of myasthenia gravis, among others. By binding to the C5 protein in the complement system, eculizumab effectively inhibits cellular hemolysis and autoimmune reactions. Despite this effective treatment, some patients reported no improvement in symptoms. Genetic sequencing revealed three distinct C5 mutations in the non-responders and these polymorphisms appeared to be most prevalent among Japanese, Korean and African populations. Here, we present an overview of the current and potential future applications of eculizumab, as well as the disadvantages of eculizumab treatment in patients with C5 polymorphisms.

MOG CNS Autoimmunity and MOGAD

At one time considered a possible form of neuromyelitis optica (NMO) spectrum disorder (NMOSD), it is now accepted that myelin oligodendrocyte glycoprotein (MOG) antibody (Ab)-associated disorder (MOGAD) is a distinct entity from either NMO or multiple sclerosis (MS) and represents a broad spectrum of clinical phenotypes. Whereas Abs targeting aquaporin-4 (AQP4) in NMO are pathogenic, the extent that anti-MOG Abs contribute to CNS damage in MOGAD is unclear. Both AQP4-specific Abs in NMO and MOG-specific Abs in MOGAD are predominantly IgG1, a T cell-dependent immunoglobulin (Ig) subclass. Key insights in neuroimmunology and MOGAD pathogenesis have been learned from MOG experimental autoimmune encephalomyelitis (EAE), described 2 decades before the term MOGAD was introduced. MOG-specific T cells are required in MOG EAE, and while anti-MOG Abs can exacerbate EAE and CNS demyelination, those Abs are neither necessary nor sufficient to cause EAE. Knowledge regarding the spectrum of MOGAD clinical and radiologic presentations is advancing rapidly, yet our grasp of MOGAD pathogenesis is incomplete. Understanding both the humoral and cellular immunology of MOGAD has implications for diagnosis, treatment, and prognosis.

Astrocyte-secreted C3 signaling impairs neuronal development and cognition in autoimmune diseases

Neuromyelitis optica (NMO) arises from primary astrocytopathy induced by autoantibodies targeting the astroglial protein aquaporin 4 (AQP4), leading to severe neurological sequelae such as vision loss, motor deficits, and cognitive decline. Mounting evidence has shown that dysregulated activation of complement components contributes to NMO pathogenesis. Complement C3 deficiency has been shown to protect against hippocampal neurodegeneration and cognitive decline in neurodegenerative disorders (e.g., Alzheimer's disease, AD) and autoimmune diseases (e.g., multiple sclerosis, MS). However, whether inhibiting the C3 signaling can ameliorate cognitive dysfunctions in NMO remains unclear. In this study, we found that the levels of C3a, a split product of C3, significantly correlate with cognitive impairment in our patient cohort. In response to the stimulation of AQP4 autoantibodies, astrocytes were activated to secrete complement C3, which inhibited the development of cultured neuronal dendritic arborization. NMO mouse models exhibited reduced adult hippocampal newborn neuronal dendritic and spine development, as well as impaired learning and memory functions, which could be rescued by decreasing C3 levels in astrocytes. Mechanistically, we found that C3a engaged with C3aR to impair neuronal development by dampening β-catenin signalling. Additionally, inhibition of the C3-C3aR-GSK3β/β-catenin cascade restored neuronal development and ameliorated cognitive impairments. Collectively, our results suggest a pivotal role of the activation of the C3-C3aR network in neuronal development and cognition through mediating astrocyte and adult-born neuron communication, which represents a potential therapeutic target for autoimmune-related cognitive impairment diseases.

Overview and Diagnostic Approach in Autoimmune Neurology

OBJECTIVE

The field of autoimmune neurology is rapidly evolving. This article reviews the epidemiology and pathophysiology as well as current approaches to clinical and paraclinical assessment, testing paradigms, and general principles of treatment.

LATEST DEVELOPMENTS

Improved recognition of autoimmune diagnoses among patients who have phenotypically diverse, subacute onset neurologic presentations is facilitated by disease-specific antibody biomarker discovery. These antibodies have varying associations with paraneoplastic causation (from no association to greater than 70% positive predictive value), immunotherapy responses, and outcomes. To simplify assessment in an increasingly complex discipline, neurologic phenotype-specific serum and CSF antibody evaluations are recommended. Clinical trials have led to the approval of monoclonal therapies for neuromyelitis optica spectrum disorder (NMOSD) and are underway for N-methyl-d-aspartate (NMDA) receptor and leucine-rich glioma inactivated protein 1 (LGI1) encephalitides.

ESSENTIAL POINTS

Autoimmune neurology is now a mainstream subspecialty, consisting of disorders with diverse presentations detectable using antibody testing of serum and CSF. Early and sustained immunotherapy (eg, corticosteroids, intravenous immunoglobulin [IVIg], plasma exchange) is recommended and may be supplemented by immune suppressants (eg, rituximab or cyclophosphamide) to sustain responses and optimize outcomes.

NMOSD and MOGAD

OBJECTIVE

This article reviews the clinical features, MRI characteristics, diagnosis, and treatment of aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder (AQP4-NMOSD) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). The main differences between these disorders and multiple sclerosis (MS), the most common demyelinating disease of the central nervous system (CNS), are also highlighted.

LATEST DEVELOPMENTS

The past 20 years have seen important advances in understanding rare demyelinating CNS disorders associated with AQP4 IgG and myelin oligodendrocyte glycoprotein (MOG) IgG. The rapidly expanding repertoire of immunosuppressive agents approved for the treatment of AQP4-NMOSD and emerging as potentially beneficial in MOGAD mandates prompt recognition of these diseases. Most of the recent literature has focused on the identification of clinical and MRI features that help distinguish these diseases from each other and MS, simultaneously highlighting major diagnostic pitfalls that may lead to misdiagnosis. An awareness of the limitations of currently available assays for AQP4 IgG and MOG IgG detection is fundamental for identifying rare false antibody positivity and avoiding inappropriate treatments. For this purpose, diagnostic criteria have been created to help the clinician interpret antibody testing results and recognize the clinical and MRI phenotypes associated with AQP4-NMOSD and MOGAD.

ESSENTIAL POINTS

An awareness of the specific clinical and MRI features associated with AQP4-NMOSD and MOGAD and the limitations of currently available antibody testing assays is crucial for a correct diagnosis and differentiation from MS. The growing availability of effective treatment options will lead to personalized therapies and improved outcomes.

Therapeutic Approach to Autoimmune Neurologic Disorders

OBJECTIVE

Autoimmune neurologic disorders encompass a broad category of diseases characterized by immune system attack of the central, peripheral, or autonomic nervous systems. This article provides information on both acute and maintenance immunotherapy used to treat autoimmune neurologic disorders as well as a review of symptomatic management and special considerations when caring for patients with these diseases.

LATEST DEVELOPMENTS

Over the past 20 years, more than 50 antibodies have been identified and associated with autoimmune neurologic disorders. Although advances in diagnostic testing have allowed for more rapid diagnosis, the therapeutic approach to these disorders has largely continued to rely on expert opinion, case series, and case reports. With US Food and Drug Administration (FDA) approval of biologic agents to treat neuromyelitis optica spectrum disorder (NMOSD) and myasthenia gravis as well as ongoing clinical trials for the treatment of autoimmune encephalitis, the landscape of immunotherapy options continues to expand. Consideration of the unique pathogenesis of individual autoimmune neurologic disorders as well as the mechanism of action of the diverse range of treatment options can help guide treatment decisions today while evidence from clinical trials informs new therapeutics in the future.

ESSENTIAL POINTS

Recognizing patients who have a clinical history and examination findings concerning for autoimmune neurologic disorders and conducting a thorough and directed imaging and laboratory evaluation aimed at ruling out mimics, identifying specific autoimmune syndromes, and screening for factors that may have an impact on immunotherapy choices early in the clinical course are essential to providing optimal care for these patients. Providers must consider immunotherapy, symptomatic treatment, and a multidisciplinary approach that addresses each patient's unique needs when treating patients with autoimmune neurologic disorders.

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.

Neuromyelitis optica spectrum disorder: pathophysiological approach

Aim: To review the main pathological findings of Neuromyelitis Optica Spectrum Disorder (NMOSD) associated with the presence of autoantibodies to aquaporin-4 (AQP4) as well as the mechanisms of astrocyte dysfunction and demyelination. Methods: An comprehensive search of the literature in the field was carried out using the database of The National Center for Biotechnology Information from . Systematic searches were performed until July 2022. Results: NMOSD is an inflammatory and demyelinating disease of the central nervous system mainly in the areas of the optic nerves and spinal cord, thus explaining mostly the clinical findings. Other areas affected in NMOSD are the brainstem, hypothalamus, and periventricular regions. Relapses in NMOSD are generally severe and patients only partially recover. NMOSD includes clinical conditions where autoantibodies to aquaporin-4 (AQP4-IgG) of astrocytes are detected as well as similar clinical conditions where such antibodies are not detected. AQP4 are channel-forming integral membrane proteins of which AQ4 isoforms are able to aggregate in supramolecular assemblies termed orthogonal arrays of particles (OAP) and are essential in the regulation of water homeostasis and the adequate modulation of neuronal activity and circuitry. AQP4 assembly in orthogonal arrays of particles is essential for AQP4-IgG pathogenicity since AQP4 autoantibodies bind to OAPs with higher affinity than for AQP4 tetramers. NMOSD has a complex background with prominent roles for genes encoding cytokines and cytokine receptors. AQP4 autoantibodies activate the complement-mediated inflammatory demyelination and the ensuing damage to AQP4 water channels, leading to water influx, necrosis and axonal loss. Conclusions: NMOSD as an astrocytopathy is a nosological entity different from multiple sclerosis with its own serological marker: immunoglobulin G-type autoantibodies against the AQP4 protein which elicits a complement-dependent cytotoxicity and neuroinflammation. Some patients with typical manifestations of NMSOD are AQP4 seronegative and myelin oligodendrocyte glycoprotein positive. Thus, the detection of autoantibodies against AQP4 or other autoantibodies is crucial for the correct treatment of the disease and immunosuppressant therapy is the first choice.

Moving towards a new era for the treatment of neuromyelitis optica spectrum disorders

Neuromyelitis optica spectrum disorders (NMOSD) include a rare group of autoimmune conditions that primarily affect the central nervous system. They are characterized by inflammation and damage to the optic nerves, brain and spinal cord, leading to severe vision impairment, locomotor disability and sphynteric disturbances. In the majority of cases, NMOSD arises due to specific serum immunoglobulin G (IgG) autoantibodies targeting aquaporin 4 (AQP4-IgG), which is the most prevalent water-channel protein of the central nervous system. Early diagnosis and treatment are crucial to manage symptoms and prevent long-term disability in NMOSD patients. NMOSD were previously associated with a poor prognosis. However, recently, a number of randomized controlled trials have demonstrated that biological therapies acting on key elements of NMOSD pathogenesis, such as B cells, interleukin-6 (IL-6) pathway, and complement, have impressive efficacy in preventing the occurrence of clinical relapses. The approval of the initial drugs marks a revolutionary advancement in the treatment of NMOSD patients, significantly transforming therapeutic options and positively impacting their prognosis. In this review, we will provide an updated overview of the key immunopathological, clinical, laboratory, and neuroimaging aspects of NMOSD. Additionally, we will critically examine the latest advancements in NMOSD treatment approaches. Lastly, we will discuss key aspects regarding optimization of treatment strategies and their monitoring.

Efficacy and safety of mycophenolate mofetil for steroid reduction in neuromyelitis optica spectrum disorder: a prospective cohort study

Neuromyelitis optica spectrum disorder (NMOSD) is a rare autoimmune inflammatory disease that can affect multiple generations and cause complications with long-term prednisolone treatment. This study aimed to evaluate the efficacy and safety of mycophenolate mofetil (MMF) in preventing NMOSD relapse while reducing prednisolone dosage. The trial involved nine patients with NMOSD who received MMF along with prednisolone dose reduction. MMF was effective in achieving prednisolone dose reduction without relapse in 77.8% of patients, with a significant decrease in mean annualized relapse rate. All adverse events were mild. The findings suggest that MMF could be a viable treatment option for middle-aged and older patients who require steroid reduction.Clinical trial registration number: jRCT, jRCTs051180080. Registered February 27th, 2019-retrospectively registered, https://jrct.niph.go.jp/en-latest-detail/jRCTs051180080.

B cell-targeting chimeric antigen receptor T cells as an emerging therapy in neuroimmunological diseases

BACKGROUND

Neuroimmunology research and development has been marked by substantial advances, particularly in the treatment of neuroimmunological diseases, such as multiple sclerosis, myasthenia gravis, neuromyelitis optica spectrum disorders, and myelin oligodendrocyte glycoprotein antibody disease. With more than 20 drugs approved for multiple sclerosis alone, treatment has become more personalised. The approval of disease-modifying therapies, particularly those targeting B cells, has highlighted the role of immunotherapeutic interventions in the management of these diseases. Despite these successes, challenges remain, particularly for patients who do not respond to conventional therapies, underscoring the need for innovative approaches.

RECENT DEVELOPMENTS

The approval of monoclonal antibodies, such as ocrelizumab and ofatumumab, which target CD20, and inebilizumab, which targets CD19, for the treatment of various neuroimmunological diseases reflects progress in the understanding and management of B-cell activity. However, the limitations of these therapies in halting disease progression or activity in patients with multiple sclerosis or neuromyelitis optica spectrum disorders have prompted the exploration of cell-based therapies, particularly chimeric antigen receptor (CAR) T cells. Initially successful in the treatment of B cell-derived malignancies, CAR T cells offer a novel therapeutic mechanism by directly targeting and eliminating B cells, potentially overcoming the shortcomings of antibody-mediated B cell depletion. WHERE NEXT?: The use of CAR T cells in autoimmune diseases and B cell-driven neuroimmunological diseases shows promise as a targeted and durable option. CAR T cells act autonomously, penetrating deep tissue and effectively depleting B cells, especially in the CNS. Although the therapeutic potential of CAR T cells is substantial, their application faces hurdles such as complex logistics and management of therapy-associated toxic effects. Ongoing and upcoming clinical trials will be crucial in determining the safety, efficacy, and applicability of CAR T cells. As research progresses, CAR T cell therapy has the potential to transform treatment for patients with neuroimmunological diseases. It could offer extended periods of remission and a new standard in the management of autoimmune and neuroimmunological disorders.

Network Meta-analysis of Ravulizumab and Alternative Interventions for the Treatment of Neuromyelitis Optica Spectrum Disorder

INTRODUCTION

Anti-aquaporin-4 antibody-positive (AQP4-Ab+) neuromyelitis optica spectrum disorder (NMOSD) is a complement-mediated autoimmune disease in which unpredictable and relapsing attacks on the central nervous system cause irreversible and accumulating damage. Comparative efficacy of new NMOSD therapies, such as ravulizumab, with established therapies is critical in making informed treatment decisions.

METHODS

Efficacy of ravulizumab relative to established AQP4-Ab+ NMOSD treatments, such as eculizumab, inebilizumab, and satralizumab, was evaluated in a Bayesian network meta-analysis (NMA). Data were extracted from trials identified by a systematic literature review. The final evidence base consisted of 17 publications representing five unique and global studies (PREVENT, N-MOmentum, SAkuraSky, SAkuraStar, and CHAMPION-NMOSD). The primary endpoint was time-to-first relapse; other outcomes included annualized relapse rates (ARRs).

RESULTS

For patients receiving monotherapy (monoclonal antibody only), ravulizumab was associated with a lower risk of relapse than inebilizumab (hazard ratio [HR] 0.09, 95% credible interval [CrI] 0.02, 0.57) or satralizumab (HR 0.08, 95% CrI 0.01, 0.55) and was comparable to eculizumab (HR 0.86, 95% Crl 0.16, 4.52). Ravulizumab + immunosuppressive therapy (IST) was associated with a lower risk of relapse than satralizumab + IST (HR 0.15, 95% CrI 0.03, 0.78); the comparison with eculizumab + IST suggested no difference. No patients treated with inebilizumab received background IST and were thus excluded from analysis. The ARR with ravulizumab monotherapy was 98% lower compared with inebilizumab (rate ratio [RR] 0.02, 95% Crl 0.00, 0.38) and satralizumab (RR 0.02, 95% Crl 0.00, 0.42) monotherapies. The ARR with ravulizumab ± IST showed the strongest treatment-effect estimates compared with other interventions.

CONCLUSION

In the absence of head-to-head randomized controlled trials, NMA results suggest ravulizumab, a C5 inhibitor, is likely to be more effective in preventing NMOSD relapse in patients with AQP4-Ab+ NMOSD when compared with other treatments having different methods of action.

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.

Soluble biomarkers for Neuromyelitis Optica Spectrum Disorders: a mini review

The Neuromyelitis Optica Spectrum Disorders (NMOSD) constitute a spectrum of rare autoimmune diseases of the central nervous system characterized by episodes of transverse myelitis, optic neuritis, and other demyelinating attacks. Previously thought to be a subtype of multiple sclerosis, NMOSD is now known to be a distinct disease with unique pathophysiology, clinical course, and treatment options. Although there have been significant recent advances in the diagnosis and treatment of NMOSD, the field still lacks clinically validated biomarkers that can be used to stratify disease severity, monitor disease activity, and inform treatment decisions. Here we review many emerging NMOSD biomarkers including markers of cellular damage, neutrophil-to-lymphocyte ratio, complement, and cytokines, with a focus on how each biomarker can potentially be used for initial diagnosis, relapse surveillance, disability prediction, and treatment monitoring.

Design and Biological Evaluation of the Long-Acting C5-Inhibited Ornithodoros moubata Complement Inhibitor (OmCI) Modified with Fatty Acid

Disorder of complement response is a significant pathogenic factor causing some autoimmune and inflammation diseases. The Ornithodoros moubata Complement Inhibitor (OmCI), a small 17 kDa natural protein, was initially extracted from soft tick salivary glands. The protein was found binding to complement C5 specifically, inhibiting the activation of the complement pathway, which is a successful therapeutic basis of complement-mediated diseases. However, a short half-life due to rapid renal clearance is a common limitation of small proteins for clinical application. In this study, we extended the half-life of OmCI by modifying it with fatty acid, which was a method used to improve the pharmacokinetics of native peptides and proteins. Five OmCI mutants were initially designed, and single-site cysteine mutation was introduced to each of them. After purification, four OmCI mutants were obtained that showed similar in vitro biological activities. Three mutants of them were subsequently coupled with different fatty acids by nucleophilic substitution. In total, 15 modified derivatives were screened and tested for anticomplement activity in vitro. The results showed that coupling with fatty acid would not significantly affect their complement-inhibitory activity (CH50 and AH50). OmCIT90C-CM02 and OmCIT90C-CM05 were validated as the applicable OmCI bioconjugates for further pharmacokinetic assessments, and both showed improved plasma half-life in mice compared with unmodified OmCI (15.86, 17.96 vs 2.57 h). In summary, our data demonstrated that OmCI conjugated with fatty acid could be developed as the potential long-acting C5 complement inhibitor in the clinic.

Real-world experience with eculizumab and switching to ravulizumab for generalized myasthenia gravis

OBJECTIVE

Eculizumab and ravulizumab are complement protein C5 inhibitors, showing efficacy and tolerability for patients with anti-acetylcholine receptor-positive (AChR+) generalized myasthenia gravis (gMG) in phase 3 clinical trials and subsequent analyses. The purpose of the present study was to evaluate the clinical significance of eculizumab and switching to ravulizumab for refractory AChR+ gMG patients in the real-world experience.

METHODS

Among the database of Japan MG registry survey 2021, we studied AChR+ gMG patients who received eculizumab. We also evaluated these patients who switched from eculizumab to ravulizumab. Responder was defined as an improvement of at least 3 points in MG-ADL. We performed a questionnaire of preference between eculizumab and ravulizumab.

RESULTS

Among 1,106 patients with AChR+ gMG, 36 patients (3%) received eculizumab (female 78%, mean age 56.0 years). Eculizumab was preferentially used in severe and refractory MG patients. The duration of eculizumab treatment was 35 months on average. MG-ADL improved from 9.4 ± 4.9 to 5.9 ± 5.1, and 25 (70%) of the 36 gMG patients were responders. Postintervention status was markedly improved after the eculizumab treatment. Of 13 patients who did not continue eculizumab, 6 showed insufficiencies. Early onset MG was most effective. However, 15 patients switching from eculizumab to ravulizumab kept favorable response and tolerability. Questionnaire surveys showed preference for ravulizumab over eculizumab.

INTERPRETATION

Eculizumab and switching to ravulizumab showed to be effective for refractory AChR+ gMG patients in clinical settings.

Neuromyelitis Optica Spectrum Disorders and Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease

For over two centuries, clinicians have been aware of various conditions affecting white matter which had come to be grouped under the umbrella term multiple sclerosis. Within the last 20 years, specific scientific advances have occurred leading to more accurate diagnosis and differentiation of several of these conditions including, neuromyelitis optica spectrum disorders and myelin oligodendrocyte glycoprotein antibody disease. This new understanding has been coupled with advances in disease-modifying therapies which must be accurately applied for maximum safety and efficacy.

Newly emerging type B insulin resistance (TBIR) during treatment with eculizumab for AQP4-IgG-positive neuromyelitis optica spectrum disorder (NMOSD): fatal outcome

BACKGROUND

Aquaporin-4 immunoglobulin G (AQP4-IgG) antibody-positive neuromyelitis optica spectrum disorders (NMOSD) are frequently associated with other autoimmune disorders, including systemic lupus erythematosus (SLE). Eculizumab (ECU) is a highly effective long-term treatment for NMOSD. However, ECU is known to increase significantly the risk of infection with encapsulated bacteria and sepsis. Recently, increased insulin resistance (IR) in patients with NMOSD has been suggested. Type B IR (TBIR) is a rare autoimmune condition often accompanying or preceding SLE. TBIR has not yet been reported in NMOSD.

OBJECTIVE

To report an ECU-treated patient with AQP4-IgG-positive NMOSD who developed fatal septic complications after the emergence of TBIR.

METHODS

Description of the clinical course over a period of 8 years.

RESULTS

A female patient was diagnosed with NMOSD at the age of 16 years. A variety of disease-modifying drugs failed to achieve sufficient disease control, resulting in severe tetraparesis. Treatment with ECU was started 6 years after NMOSD diagnosis and stabilized the disease. The patient developed TBIR 8 months after initiation of ECU therapy. Following high-dose intravenous methylprednisolone therapy for a clinical relapse and three further courses of ECU, the patient was admitted with severe pneumonia caused by the encapsulated bacterium Klebsiella pneumoniae and hypoglycemia. Despite multimodal therapy, the patient died from sepsis-related multiorgan failure 18 months after initiation of ECU.

CONCLUSIONS

TBIR should be considered as differential diagnosis in patients with NMOSD presenting with disturbed glucose metabolism, irrespective of the presence of SLE. More real-world data are needed on the risk/benefit ratio of ECU treatment in patients who have co-existing autoimmune comorbidities that may compromise immune function. Strategies to mitigate the risk of serious infection in patients treated with ECU are discussed.

Extremely Longitudinally Extensive Transverse Myelitis in a Patient With Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease

Longitudinally extensive myelitis with 15 or more vertebrae in length is extremely rare, with limited evidence regarding clinical features and therapeutic response. We report a case of a 29-year-old male patient with extremely longitudinally extensive myelitis ultimately diagnosed as myelin oligodendrocyte glycoprotein-associated disease (MOGAD). The patient presented with an acute onset of meningismus, limb weakness, sensory disturbance below the C5 level, ataxia, and urinary retention. T2-weighted imaging on MRI showed an extremely longitudinally extensive spinal cord lesion ranging from C2 to the medullary conus, together with a left pontine lesion. Positive anti-myelin oligodendrocyte glycoprotein antibodies were serologically detected, which led to the diagnosis of MOGAD. Intravenous methylprednisolone followed by 1 mg/kg oral prednisolone with taper resulted in complete symptomatic and radiological resolution. The striking complete resolution despite the symptomatic and radiological severity observed in this case has been described in a few previously reported MOGAD cases. Extremely longitudinally extensive myelitis with excellent therapeutic response may be a characteristic presentation of MOGAD.

Role of C5 inhibitors in neuromyelitis optica spectrum disorders with seropositive anti-aquaporin-4 antibody: A systematic review and meta-analysis

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disorder characterized by relapses of inflammation and demyelination primarily affecting the optic nerve and the spinal cord. C5 complement inhibition is an effective therapeutic approach in the treatment of NMOSD. In this systematic review and meta-analysis, we aimed to determine the role of C5 inhibitors in the treatment of patients with seropositive anti-aquaporin-4 antibody (AQP4+IgG) NMOSD.

METHODS

This systematic review follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. Relevant articles were systematically searched through Medline, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and Web of Science databases until October 6th, 2023. We included randomized clinical trials (RCTs) that investigated the treatment with C5 inhibitors compared to placebo in patients with seropositive NMOSD. The primary endpoint was the rates of first adjudicated relapse. Secondary endpoints included different disability and quality of life measures. The random-effects model was used for all statistical analyses.

RESULTS

Two RCTs with a total of 201 patients were included. C5 inhibitors demonstrated significant reduction of first adjudicated relapse (risk ratio (RR) = 0.05, 95 % CI 0.01-0.15) and Hauser Ambulation Index (HAI) (mean difference (MD): -0.79, 95 % CI -1.27 to -0.31). There was no significant difference between the two groups in Expanded Disability Status Scale (EDSS) (MD -0.23, 95 % CI -0.54-0.08). C5 inhibitors significantly improved the mean change in EQ-5D index (MD 0.08, 95 % CI 0.01-0.14; P = 0.02); however, no significant difference was shown in the mean change in EQ-5D VAS (MD 3.79, 95 % CI -1.61 to 9.19; P = 0.17). Safety measures were comparable between C5 inhibitors and placebo.

CONCLUSION

NMOSD Patients with AQP4+IgG receiving C5 inhibitors have lower rate of relapses and improved levels of disability and quality of life. Real-world studies are warranted to establish the long-term safety of C5 inhibitors.

Statistical analyses of ordinal outcomes in randomised controlled trials: a scoping review

BACKGROUND

Randomised controlled trials (RCTs) aim to estimate the causal effect of one or more interventions relative to a control. One type of outcome that can be of interest in an RCT is an ordinal outcome, which is useful to answer clinical questions regarding complex and evolving patient states. The target parameter of interest for an ordinal outcome depends on the research question and the assumptions the analyst is willing to make. This review aimed to provide an overview of how ordinal outcomes have been used and analysed in RCTs.

METHODS

The review included RCTs with an ordinal primary or secondary outcome published between 2017 and 2022 in four highly ranked medical journals (the British Medical Journal, New England Journal of Medicine, The Lancet, and the Journal of the American Medical Association) identified through PubMed. Details regarding the study setting, design, the target parameter, and statistical methods used to analyse the ordinal outcome were extracted.

RESULTS

The search identified 309 studies, of which 144 were eligible for inclusion. The most used target parameter was an odds ratio, reported in 78 (54%) studies. The ordinal outcome was dichotomised for analysis in 47 ( 33 % ) studies, and the most common statistical model used to analyse the ordinal outcome on the full ordinal scale was the proportional odds model (64 [ 44 % ] studies). Notably, 86 (60%) studies did not explicitly check or describe the robustness of the assumptions for the statistical method(s) used.

CONCLUSIONS

The results of this review indicate that in RCTs that use an ordinal outcome, there is variation in the target parameter and the analytical approaches used, with many dichotomising the ordinal outcome. Few studies provided assurance regarding the appropriateness of the assumptions and methods used to analyse the ordinal outcome. More guidance is needed to improve the transparent reporting of the analysis of ordinal outcomes in future trials.

Interferon-γ controls aquaporin 4-specific Th17 and B cells in neuromyelitis optica spectrum disorder

Neuromyelitis optica spectrum disorder (NMOSD) is a CNS autoimmune inflammatory disease mediated by T helper 17 (Th17) and antibody responses to the water channel protein, aquaporin 4 (AQP4), and associated with astrocytopathy, demyelination and axonal loss. Knowledge about disease pathogenesis is limited and the search for new therapies impeded by the absence of a reliable animal model. In our work, we determined that NMOSD is characterized by decreased IFN-γ receptor signalling and that IFN-γ depletion in AQP4201-220-immunized C57BL/6 mice results in severe clinical disease resembling human NMOSD. Pathologically, the disease causes autoimmune astrocytic and CNS injury secondary to cellular and humoral inflammation. Immunologically, the absence of IFN-γ allows for increased expression of IL-6 in B cells and activation of Th17 cells, and generation of a robust autoimmune inflammatory response. Consistent with NMOSD, the experimental disease is exacerbated by administration of IFN-β, whereas repletion of IFN-γ, as well as therapeutic targeting of IL-17A, IL-6R and B cells, ameliorates it. We also demonstrate that immune tolerization with AQP4201-220-coupled poly(lactic-co-glycolic acid) nanoparticles could both prevent and effectively treat the disease. Our findings enhance the understanding of NMOSD pathogenesis and provide a platform for the development of immune tolerance-based therapies, avoiding the limitations of the current immunosuppressive therapies.

Disseminated Cryptococcosis Post Eculizumab Therapy: A Case Report and Literature Review

Eculizumab is a biologic medication used for the treatment of complement-related disorders including anti-acetylcholine receptor antibody-positive generalized myasthenia gravis. It targets C5 complement, preventing its cleavage into active terminal components. Thus, vaccination against encapsulated organisms is advised before starting this treatment. C5 also has a critical role against Cryptococcus neoformans infection. Here, we present a case of a 34-year-old man with a history of myasthenia gravis who was treated with prednisone and azathioprine in addition to eculizumab that was added to his regimen about a year ago, and who came to the hospital with headache, and was found to have Cryptococcus meningitis with disseminated cryptococcosis. The patient was negative for human immunodeficiency virus. He was treated with antifungal medications, and his condition improved. Although rarely reported, it is important to have a low threshold for diagnosis of cryptococcosis in patients on eculizumab given its complement inhibition mechanism of action.

Triple-fusion protein (TriFu): A potent, targeted, enzyme-like inhibitor of all three complement activation pathways

The introduction of a therapeutic anti-C5 antibody into clinical practice in 2007 inspired a surge into the development of complement-targeted therapies. This has led to the recent approval of a C3 inhibitory peptide, an antibody directed against C1s and a full pipeline of several complement inhibitors in preclinical and clinical development. However, no inhibitor is available that efficiently inhibits all three complement initiation pathways and targets host cell surface markers as well as complement opsonins. To overcome this, we engineered a novel fusion protein combining selected domains of the three natural complement regulatory proteins decay accelerating factor, factor H and complement receptor 1. Such a triple fusion complement inhibitor (TriFu) was recombinantly expressed and purified alongside multiple variants and its building blocks. We analyzed these proteins for ligand binding affinity and decay acceleration activity by surface plasmon resonance. Additionally, we tested complement inhibition in several in vitro/ex vivo assays using standard classical and alternative pathway restricted hemolysis assays next to hemolysis assays with paroxysmal nocturnal hemoglobinuria erythrocytes. A novel in vitro model of the alternative pathway disease C3 glomerulopathy was established to evaluate the potential of the inhibitors to stop C3 deposition on endothelial cells. Next to the novel engineered triple fusion variants which inactivate complement convertases in an enzyme-like fashion, stoichiometric complement inhibitors targeting C3, C5, factor B, and factor D were tested as comparators. The triple fusion approach yielded a potent complement inhibitor that efficiently inhibits all three complement initiation pathways while targeting to surface markers.

Long-term efficacy and safety of rituximab in the treatment of neuromyelitis Optica Spectrum disorder

Background

Neuromyelitis optica spectrum disorder (NMOSD) is a relapsing, autoimmune, inflammatory astrocytopathy. Rituximab for B-cell suppression is a common treatment for NMOSD; however, large-scale randomised controlled trials are lacking.

Objective

Evaluate long-term efficacy and safety of rituximab for NMOSD.

Methods

Retrospective observational study of patients with NMOSD treated with rituximab. Annualised relapse rates (ARRs) before and during rituximab treatment were evaluated; Modified Rankin Scores (mRS) were measured as a marker of disability.

Results

In total, 37 patients were included: 27 aquaporin-4-IgG-seropositive and 10 seronegative NMOSD. The predominant rituximab dosing regimen was an initial 1000 mg, split over two 500 mg infusions, two weeks apart, followed by single 500 mg doses. Over a median follow-up of 54 months, ARR for the whole cohort was 0.136 (95% CI 0.088-0.201), significantly lower than the pretreatment ARR of 0.366 (95% CI 0.271-0.483, p < 0.001). There was a significant reduction in ARR for the seropositive subgroup, but not seronegative. Significant improvement in mRS was seen post-treatment. Infections were reported in 32% of patients during follow-up; most were mild.

Conclusion

Rituximab, at doses lower than traditionally used, may be an efficacious therapy for NMOSD, with a favourable safety profile.

Time to Disability Milestones and Annualized Relapse Rates in NMOSD and MOGAD

OBJECTIVE

To investigate accumulation of disability in neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein-antibody-associated disease (MOGAD) in a changing treatment landscape. We aimed to identify risk factors for the development of disability milestones in relation to disease duration, number of attacks, and age.

METHODS

We analyzed data from individuals with NMOSD and MOGAD from the German Neuromyelitis Optica Study Group registry. Applying survival analyses, we estimated risk factors and computed time to disability milestones as defined by the Expanded Disability Status Score (EDSS).

RESULTS

We included 483 patients: 298 AQP4-IgG+ NMOSD, 52 AQP4-IgG-/MOG-IgG- NMOSD patients, and 133 patients with MOGAD. Despite comparable annualized attack rates, disability milestones occurred earlier and after less attacks in NMOSD patients than MOGAD patients (median time to EDSS 3: AQP4-IgG+ NMOSD 7.7 (95% CI 6.6-9.6) years, AQP4-IgG-/MOG-IgG- NMOSD 8.7) years, MOGAD 14.1 (95% CI 10.4-27.6) years; EDSS 4: 11.9 (95% CI 9.7-14.7), 11.6 (95% lower CI 7.6) and 20.4 (95% lower CI 14.1) years; EDSS 6: 20.1 (95% CI 16.5-32.1), 20.7 (95% lower CI 11.6), and 37.3 (95% lower CI 29.4) years; and EDSS 7: 34.2 (95% lower CI 31.1) for AQP4-IgG+ NMOSD). Higher age at onset increased the risk for all disability milestones, while risk of disability decreased over time.

INTERPRETATION

AQP4-IgG+ NMOSD, AQP4-IgG-/MOG-IgG- NMOSD, and MOGAD patients show distinctive relapse-associated disability progression, with MOGAD having a less severe disease course. Investigator-initiated research has led to increasing awareness and improved treatment strategies appearing to ameliorate disease outcomes for NMOSD and MOGAD. ANN NEUROL 2024;95:720-732.

Real-world management of patients with neuromyelitis optica spectrum disorder using satralizumab: Results from a Japanese claims database

BACKGROUND

Satralizumab, a humanized anti-interleukin-6 receptor monoclonal antibody, has been approved globally for the treatment of neuromyelitis optica spectrum disorder (NMOSD), based on positive results from two randomized, double-blind, phase 3 studies: SAkuraSky (NCT02028884) and SAkuraStar (NCT02073279). There remains an unmet need to understand the real-world management of NMOSD, especially in patients undergoing tapering of concomitant therapy. We examined real-world treatment patterns, including concomitant glucocorticoids and immunosuppressants, and relapse in satralizumab-treated patients with NMOSD, using a Japanese administrative hospital claims database.

METHODS

We used retrospective data from the Medical Data Vision hospital-based administrative claims database. The index date was the date of first satralizumab prescription and the study period was set between August 2018 and March 2022. Patients were included in the overall population if they had a first prescription for satralizumab between August 2020 and March 2022, an International Classification of Disease, Version10 code of G36.0 prior to March 2022, and were observable for ≥90 days prior to the index date. The primary endpoint was the percentage of patients with relapse-free reduction of oral glucocorticoids to 0 mg/day at 360 days of continued satralizumab treatment. Secondary endpoints included time to relapse, number of relapses after the index date while being on continuous satralizumab treatment, annualized relapse rate before and after the index date, and concomitant medication use. Relapse and dose reduction were identified using definition specifically developed for this study.

RESULTS

Of the 131 patients included in the overall population, most were female (90.8 %), aged 18-65 years (75.6 %), and were prescribed oral glucocorticoids (93.1 %). Azathioprine (19.1 %) and tacrolimus, a calcineurin inhibitor (18.3 %), were the most common immunosuppressants at index date. Six (4.6 %) patients had a history of biologic use (tocilizumab, 1 [0.8 %]; eculizumab, 5 [3.8 %]). Among 111 patients observable for 360 days pre-index, there were 0.6 ± 0.8 (mean ± SD) relapses during 360 days before the index date. The median (interquartile range) duration of satralizumab exposure was 197.0 (57.0-351.0) days. Most (125/131; 95.4 %) patients were relapse-free post-index; 6 (4.6 %) patients relapsed within 90 days after the index date, of which 2 had the first relapse within 7 days after the index date. Among 21 patients with 360-day follow-up, 6 (28.6 %) patients were on 0 mg/day dose of glucocorticoid prescription without relapse 360 days post-index. Of these 6 patients, 2 had no prescription of oral glucocorticoids at the index date and remained glucocorticoid- and relapse-free 360 days after the index date.

CONCLUSION

These real-world data support the phase 3 clinical trials. Our results, over a median duration of satralizumab exposure of 197.0 days, showed that a majority (125/131, 95.4 %) of patients were relapse-free after initiating satralizumab treatment. The number of glucocorticoid-free patients without relapse increased over time under continuous satralizumab prescription. Further studies are needed to confirm if satralizumab can be used as a potential immunosuppressant- and glucocorticoid-sparing agent.

Autoimmune central nervous system disorders: Antibody testing and its clinical utility

A rapidly expanding repertoire of neural antibody biomarkers exists for autoimmune central nervous system (CNS) disorders. Following clinical recognition of an autoimmune CNS disorder, the detection of a neural antibody facilitates diagnosis and informs prognosis and management. This review considers the phenotypes, diagnostic assay methodologies, and clinical utility of neural antibodies in autoimmune CNS disorders. Autoimmune CNS disorders may present with a diverse range of clinical features. Clinical phenotype should inform the neural antibodies selected for testing via the use of phenotype-specific panels. Both serum and cerebrospinal fluid (CSF) are preferred in the vast majority of cases but for some analytes either CSF (e.g. N-methyl-D-aspartate receptor [NMDA-R] IgG) or serum (e.g. aquaporin-4 [AQP4] IgG) specimens may be preferred. Screening using 2 methods is recommended for most analytes, particularly paraneoplastic antibodies. We utilize murine tissue-based indirect immunofluorescence assay (TIFA) with subsequent confirmatory protein-specific testing. The cellular location of the target antigen informs choice of confirmatory diagnostic assay (e.g. blot for intracellular antigens such as Hu; cell-based assay for cell surface targets such as leucine-rich glioma inactivated 1 [LGI1]). Titers of positive results have limited diagnostic utility with the exception of glutamic acid decarboxylase (GAD) 65 IgG autoimmunity, which is associated with neurological disease at higher values. While novel antibodies are typically discovered using established techniques such as TIFA and immunoprecipitation-mass spectrometry, more recent high-throughput molecular technologies (such as protein microarray and phage-display immunoprecipitation sequencing) may expedite the process of antibody discovery. Individual neural antibodies inform the clinician regarding the clinical associations, oncological risk stratification and tumor histology, the likely prognosis, and immunotherapy choice. In the era of neural antibody biomarkers for autoimmune CNS disorders, access to appropriate laboratory assays for neural antibodies is of critical importance in the diagnosis and management of these disorders.

Predictors of azathioprine and mycophenolate mofetil response in patients with neuromyelitis optica spectrum disorder: A cohort study

BACKGROUND

Relapse rates of 47 % have been reported in patients with neuromyelitis optica (NMOSD) using Azathioprine (AZA) and mycophenolate mofetil (MMF). Prediction of non-responders could help determine which patients are most likely to benefit from newer monoclonal antibody treatments from the outset.

OBJECTIVES

To identify predictors of AZA and MMF treatment response in NMOSD.

METHODS

Multicenter cohort study of NMOSD patients from Brazil and the United Kingdom, treated with AZA and MMF. An unsatisfactory response was defined as one severe or two non-severe attacks in a year. Cox regression was used to identify predictive factors of unsatisfactory response to AZA and MMF.

RESULTS

103 NMOSD patients, mean age 38 years, 83% female, and 65% of Black ethnic group were included. An unsatisfactory IS response was observed in 42% of patients over 2.5 years (IQR 1.0-8.8) years. A severe preceding attack was more common in non-responders (31.1% x 76.7%, p = <0.001). In multivariable analysis, severe attack (RR 3.13; 95 % CI 1.37-7.18, p = 0.007) or higher annualized relapse rate (RR 4.84; 95 % CI 2.01-11.65, p = < 0.001) predicted an unsatisfactory response. Interestingly, Black NMOSD patients had a lower risk of poor response (RR 0.39, 95 % CI 0.17-0.85, p = 0.019).

CONCLUSION

Severe attack and a higher annualized relapse rate before AZA or MMF initiation were associated with an unsatisfactory IS response. In patients with these characteristics, treatment with higher-efficacy drugs should be considered from the outset.

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.

Visualization and analysis of mapping knowledge domains for optic neuritis: a bibliometric research from 2013 to 2022

PURPOSE

To explore the global research trends, hotspots and frontiers of optic neuritis (ON) over the past decade through qualitative and quantitative analysis of bibliometrics.

METHODS

Publications on ON from 2013 to 2022 were retrieved from Web of Science Core Collection (WoSCC). VOSviewer and CiteSpace were mainly used to facilitate bibliometric analysis and visualization.

RESULTS

A total of 3027 papers were retrieved from peer-reviewed publications and the annual research output increased over time. Neurosciences neurology was the most published area. The USA was the most productive and influential country, and in the focus of international cooperation. University College London was the most productive organization and Charite Medical University of Berlin had the largest number of cooperating partners. Paul F contributed the largest number of publications and Wingerchuk DM ranked first among the co-cited authors. Multiple Sclerosis and Related Disorders was the most prolific journal publishing ON research. The most co-cited references mainly focused on the diagnostic criteria for neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis (MS). The keywords formed the following four clusters: the pathophysiology of MS-ON; the autoantibody markers and diagnostic criteria of NMOSD-ON and myelin oligodendrocyte glycoprotein associated disorder-ON (MOGAD-ON); the epidemiology and clinical characteristics of ON; and the treatment of ON.

CONCLUSION

This bibliometrics analysis showed a systematic view of the evolutionary process, research hotspots, and future directions of ON research. It can provide insights for ON research and valuable information for neuro-ophthalmologic specialists to evaluate research policies and promote international cooperation.

Immune-Mediated Necrotizing Myopathy (IMNM): A Story of Antibodies

Immune-mediated necrotizing myopathy (IMNM) is a rare and severe disease that corresponds to a specific entity of idiopathic inflammatory myopathy. Patients with IMNM suffer from proximal muscle weakness, and present high levels of creatine kinase and necrotic myofibers. Anti-Signal Recognition Particle (SRP) and anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase autoantibodies (HMGCR) have recently been identified in two thirds of patients with IMNM and are used as a hallmark of the disease. In this review, we provide a detailed description of these antibodies and the tests used to detect them in the serum of patients. Based on in vitro studies and mouse models of IMNM, we discuss the role of autoantibodies in the pathogenesis of the disease. Finally, in the light of the latest knowledge, we conclude with a review of recent therapeutic approaches in IMNM.

Anti-aquaporin-4 immune complex stimulates complement-dependent Th17 cytokine release in neuromyelitis optica spectrum disorders

Proinflammatory cytokines, such as (IL: interleukin) IL-6 and IL-17A, and complement fixation are critical in the immunopathogenesis of neuromyelitis optica spectrum disorders (NMOSD). Blocking the IL-6 receptor or the C5 complement pathway reduces relapse risk. However, the role of interleukin (IL)-6 and complement in aquaporin-4 (AQP4) autoimmunity remains unclear. To investigate the role of the anti-AQP4 immunoglobulin (AQP4-IgG)/AQP4 immunocomplex on the induction and profile of ex vivo cytokine and surface marker expression in peripheral blood mononuclear cells (PBMC) culture. Isolated PBMCs obtained from 18 patients with AQP4-IgG-seropositive-NMOSD (8 treatment-naive, 10 rituximab-treated) or ten healthy controls were cultured with AQP4-immunocomplex with or without complement. Changes in PBMC surface markers and cytokine expression were profiled using flow cytometry and ELISA. PBMCs derived from treatment-naive NMOSD patients stimulated with a complex mixture of serum complement proteins produced significant elevations of IL-17A and IL-6. Rituximab-treated patients also exhibited higher IL-6 but not IL-17A release. IL-6 and IL-17A elevations are not observed without complement. Co-stimulation of PBMCs with AQP4-IgG/AQP4 immunocomplex and complement prompts a Th17-biased response consistent with the inflammatory paradigm observed in NMOSD. A possible inflammation model is proposed via antigen-specific autoreactive peripheral blood cells, including NK/NKT cells.

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

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

Measuring the economic burden of neuromyelitis optica spectrum disorder in Colombia

OBJECTIVE

To assess the economic burden of neuromyelitis optica spectrum disorder (NMOSD) in the Colombian context.

METHODS

Analyses were conducted from a societal perspective using the prevalence-based approach. Costs were expressed in 2022 US dollars (1 USD = $3,914.46 COP). Direct medical costs were assessed from a bottom-up approach. Indirect costs included loss of productivity of the patient and their caregivers. The economic burden of NMOSD in Colombia was estimated as the sum of direct and indirect costs.

RESULTS

The direct cost of treating a patient with NMOSD was USD$ 8,149.74 per year. When projecting costs nationwide, NMOSD would cost USD$ 7.2 million per year. Of these costs, 53.5% would be attributed to relapses and 34.4% to pharmacological therapy. Indirect costs potentially attributed to NMOSD in Colombia were estimated at USD$ 1.5 million per year per cohort. Of these, 78% are attributable to loss of patient productivity, mainly due to reduced access to the labor market and premature mortality.

CONCLUSIONS

The NMOSD has a representative economic burden at the patient level, with direct costs, particularly related to relapses and medicines, being the main component of total costs. These findings are useful evidence that requires attention from public policymakers in Colombia.

Risks and outcomes of pregnancy in neuromyelitis optica spectrum disorder: A comprehensive review

Neuromyelitis optica spectrum disorder (NMOSD) is a rare central nervous system autoimmune disease. Aquaporin-4 antibody (AQP4-IgG) is present in over 75% of cases and criteria also exist for the diagnosis of seronegative NMOSD. AQP4-IgG NMOSD has a strong female predominance (9:1 ratio), with a median onset age of 40 years. Pregnancy in those with NMOSD is therefore an important topic. Fecundity in NMOSD is likely impaired, and for females who conceive, obstetric complications including miscarriages and pre-eclampsia are significantly higher in NMOSD compared to the general population and in related conditions such as multiple sclerosis (MS). In contrast to MS, NMOSD disease activity does not subside during pregnancy. Also, relapse risk substantially rises above pre-pregnancy rates in the early postpartum period. In view of the evolving landscape of NMOSD, we provide a contemporary update of the impacts of pregnancy in NMOSD.

Myasthenia gravis: the changing treatment landscape in the era of molecular therapies

Myasthenia gravis (MG) is an autoimmune disorder that affects the neuromuscular junction, leading to muscle weakness and fatigue. MG is caused by antibodies against the acetylcholine receptor (AChR), the muscle-specific kinase (MuSK) or other AChR-related proteins that are expressed in the postsynaptic muscle membrane. The standard therapeutic approach for MG has relied on acetylcholinesterase inhibitors, corticosteroids and immunosuppressants, which have shown good efficacy in improving MG-related symptoms in most people with the disease; however, these therapies can carry a considerable burden of long-term adverse effects. Moreover, up to 15% of individuals with MG exhibit limited or no response to these standard therapies. The emergence of molecular therapies, including monoclonal antibodies, B cell-depleting agents and chimeric antigen receptor T cell-based therapies, has the potential to revolutionize the MG treatment landscape. This Review provides a comprehensive overview of the progress achieved in molecular therapies for MG associated with AChR antibodies and MuSK antibodies, elucidating both the challenges and the opportunities these therapies present to the field. The latest developments in MG treatment are described, exploring the potential for personalized medicine approaches.