Safety and efficacy of rozanolixizumab in patients with generalised myasthenia gravis (MycarinG): a randomised, double-blind, placebo-controlled, adaptive phase 3 study

Clinical meaningfulness and psychometric robustness of the MG Symptoms PRO scales in clinical trials in adults with myasthenia gravis

Objectives

The objective of this research was to generate psychometric evidence supporting the myasthenia gravis (MG) symptoms patient-reported outcome (PRO) scales as a fit-for-purpose measure of severity of core symptoms of MG and provide information allowing their meaningful interpretation using data from a phase 3 study in MG.

Methods

Data from the MycarinG study, a phase 3 study of rozanolixizumab in patients with generalized MG who experience moderate to severe symptoms (ClinicalTrials.gov Identifier: NCT03971422) were analyzed with both classical test theory (CTT) and Rasch measurement theory (RMT). Meaningful within-individual change and group-level meaningful change were estimated for three MG Symptoms PRO scales using anchor- and distribution-based methods. Anchor-based methods used patient global impression of severity (PGIS) and change (PGIC) in MG symptoms as anchors.

Results

Good measurement properties of the MG Symptoms PRO scales were shown in the sample of 200 participants: good to excellent reliability (test-retest and internal consistency reliability) and validity (associations between items and scores within the MG Symptoms PRO scales and between the MG Symptoms PRO scores and other clinical outcomes-MG ADL, QMG score, MGC score, and MGFA classes-were as expected); and the items showed good coverage of the continuum and fit to the Rasch model. Triangulation of the anchor- and distribution-based method results led to the definition of clinically meaningful within-patient improvement in scores for Muscle Weakness Fatigability (-16.67), Physical Fatigue (-20.00), and Bulbar Muscle Weakness (-20.00), with associated ranges. Benchmarks are also proposed for the interpretation of group-level results.

Conclusion

The strong psychometric performance of the MG Symptoms PRO scales and the information generated to guide its interpretation supports its use in clinical trials for demonstrating the clinical benefits of new treatments targeting core symptoms of MG (muscle weakness fatigability, physical fatigue, bulbar muscle weakness, respiratory muscle weakness, and ocular muscle weakness).

Ravulizumab use for acetylcholine receptor-positive generalized myasthenia gravis in clinical practice

Purpose

To describe the early experience of ravulizumab use in acetylcholine receptor antibody-positive generalized myasthenia gravis (AChR+ve gMG).

Methods

This multicenter retrospective study included AChR+ve gMG patients who were treated with ravulizumab and had both pre- and post-ravulizumab myasthenia gravis activities of daily living (MG-ADL) scores. Clinical information regarding MG history, concomitant treatment(s), MG-ADL, other MG-specific measures, and adverse events were recorded.

Results

A total of 18 patients with mean age of 61.83 (±16.08, n = 18) years were included in this cohort. In 10 complement inhibitor naive patients, a clinically meaningful reduction in mean Mg-ADL (baseline: 6.6 (±3.58) vs. 4.4 (±2.28), post ravulizumab) was seen. 6 out of 10 patients (60%) had clinically meaningful reduction post ravulizumab and two achieved minimum symptom expression (MSE). In 8 patients switched from eculizumab to ravulizumab, further reduction was noted in post ravulizumab mean MG-ADL (Baseline: 3.25 (±3.34) vs. 1.5 (±2.34) post ravulizumab). None of the patients who switched from eculizumab to ravulizumab experienced worsening symptoms. Eleven out of 14 (78.5%) patients on prednisone therapy were able to reduce their prednisone dose post-ravulizumab. None of the patients experienced any major side effects.

Conclusion

In our clinical practice, 60% of AChR+ve gMG complement inhibitor naive patients experienced a clinically meaningful improvement in MG-ADL scores with ravulizumab. Patients were safely switched from eculizumab to ravulizumab and had further improvement in their mean MG-ADL scores. Of those on prednisone therapy, the majority were able to reduce their prednisone dosage.

Targeting autoimmune mechanisms by precision medicine in Myasthenia Gravis

Myasthenia Gravis (MG) is a chronic disabling autoimmune disease caused by autoantibodies to the neuromuscular junction (NMJ), characterized clinically by fluctuating weakness and early fatigability of ocular, skeletal and bulbar muscles. Despite being commonly considered a prototypic autoimmune disorder, MG is a complex and heterogeneous condition, presenting with variable clinical phenotypes, likely due to distinct pathophysiological settings related with different immunoreactivities, symptoms' distribution, disease severity, age at onset, thymic histopathology and response to therapies. Current treatment of MG based on international consensus guidelines allows to effectively control symptoms, but most patients do not reach complete stable remission and require life-long immunosuppressive (IS) therapies. Moreover, a proportion of them is refractory to conventional IS treatment, highlighting the need for more specific and tailored strategies. Precision medicine is a new frontier of medicine that promises to greatly increase therapeutic success in several diseases, including autoimmune conditions. In MG, B cell activation, antibody recycling and NMJ damage by the complement system are crucial mechanisms, and their targeting by innovative biological drugs has been proven to be effective and safe in clinical trials. The switch from conventional IS to novel precision medicine approaches based on these drugs could prospectively and significantly improve MG care. In this review, we provide an overview of key immunopathogenetic processes underlying MG, and discuss on emerging biological drugs targeting them. We also discuss on future direction of research to address the need for patients' stratification in endotypes according with genetic and molecular biomarkers for successful clinical decision making within precision medicine workflow.

Pharmacotherapeutic advances in fibromyalgia: what's new on the horizon?

INTRODUCTION

This review delves into Fibromyalgia Syndrome (FMS), a chronic pain condition demanding thorough understanding for precise diagnosis and treatment. Yet, a definitive pharmacological solution for FMS remains elusive.

AREAS COVERED

In this article, we systematically analyze various pharmacotherapeutic prospects for FMS treatment, organized into sections based on the stage of drug development and approval. We begin with an overview of FDA-approved drugs, discussing their efficacy in FMS treatment. Next, we delve into other medications currently used for FMS but still undergoing further study, including opioids and muscle relaxants. Further, we evaluate the evidence behind medications that are currently under study, such as cannabinoids and naltrexone. Lastly, we explore new drugs that are in phase II trials. Our research involved a thorough search on PUBMED, Google Scholar, and clinicaltrials.gov. We also discuss the action mechanisms of these drugs and their potential use in specific patient groups.

EXPERT OPINION

A focus on symptom-driven, combination therapy is crucial in managing FMS. There is also a need for ongoing research into drugs that target neuroinflammation, immunomodulation, and the endocannabinoid system. Bridging the gap between benchside research and clinical application is challenging, but it holds potential for more targeted and effective treatment strategies.

Real-World experience with efgartigimod in patients with myasthenia gravis

Recommendations for the treatment of myasthenia gravis (MG) have been difficult to develop because of limited evidence from large randomized controlled trials. New drugs and treatment approaches have recently been shown to be effective in phase 3 studies in seropositive generalized (g) MG. One such drug is efgartigimod, a human-Fc-fragment of IgG1, with a high affinity for the endosomal FcRn. We conducted a multicenter study to evaluate the real-world clinical and safety effects of efgartigimod in 22 gMG patients. We evaluated the strategies for the timing of re-treatment with it. The participants received a total of 59 efgartigimod -treatment cycles. The median number of cycles was 2 (range 1-6). Twenty patients (86.3%) improved by at least 2 MG-ADL points after the first treatment cycle. The median MG-ADL score at baseline was 6.5 (range: 3-17) and 2.5 (range: 0-9) post-treatment (p < 0.001). A consistent improvement of at least 2 points in the MG-ADL score after each cycle occurs in 18 patients. The effect duration of the treatment was usually between 4 and 12 weeks. Two major clinical patterns of treatment response were found. Treatment with efgartigimod was also associated with significant reductions of prednisone doses Overall, the treatment was safe and associated with only minor adverse events. The single fatality was apparently due tosevere respiratory failure. We found that efgartigimod is clinically effective, may be used as a steroid sparing agent and is generally safe for gMG patients. We recommend a personalized preventive treatment approach until clinical stabilization, followed by discontinuation and periodic evaluations.

FcRn Inhibitor Therapies in Neurologic Diseases

In the last decade, the landscape of treating autoimmune diseases has evolved with the emergence and approval of novel targeted therapies. Several new biological agents offer selective and target-specific immunotherapy and therefore fewer side effects, such as neonatal Fc receptor (FcRn)-targeting therapy. Neonatal Fc receptor-targeted therapies are engineered to selectively target FcRn through various methods, such as Fc fragments or monoclonal anti-FcRn antibodies. These approaches enhance the breakdown of autoantibodies by blocking the immunoglobulin G recycling pathway. This mechanism reduces overall plasma immunoglobulin levels, including the levels of pathogenic autoantibodies, without affecting the other immunoglobulin class immunoglobulin A, immunoglobulin E, immunoglobulin M, and immunoglobulin D levels. Drugs that inhibit FcRn include efgartigimod, rozanolixizumab, batoclimab, and nipocalimab. These medications can be administered either intravenously or subcutaneously. Numerous clinical trials are currently underway to investigate their effectiveness, safety, and tolerability in various neurological conditions, including myasthenia gravis and other neurological disorders such as chronic inflammatory demyelinating polyneuropathy, myositis, neuromyelitis optica, and myelin oligodendrocyte glycoprotein antibody disease. Positive results from clinical trials of efgartigimod and rozanolixizumab led to their approval for the treatment of generalized myasthenia gravis. Additional clinical trials are still ongoing. Neonatal Fc receptor inhibitor agents seem to be well tolerated. Reported adverse events include headache (most commonly observed with efgartigimod and rozanolixizumab), upper respiratory tract infection, urinary tract infection, diarrhea, pyrexia, and nausea. Additionally, some of these agents may cause transient hypoalbuminemia and hypercholesterolemia notably reported with batoclimab and nipocalimab. In this review, we discuss the available clinical data for FcRN inhibitor agents in treating different neurological autoimmune diseases.

Efficacy and safety of tocilizumab in patients with refractory generalized myasthenia gravis

BACKGROUND

We aimed to compare the efficacy of tocilizumab with conventional immunotherapy in refractory patients with acetylcholine receptor antibody-positive (AChR-Ab+) generalized myasthenia gravis (gMG).

METHODS

This single-center prospective cohort study was based on patients from an MG registry study in China and conducted from February 10, 2021 to March 31, 2022. Adult refractory patients with AChR-Ab+ gMG were assigned to tocilizumab or conventional immunotherapy groups. The primary efficacy outcome was the mean difference of MG activities of daily living (MG-ADL) change at weeks 4, 8, 12, 16, 20, 24 corresponding to that at the baseline between the two groups. A generalized estimating equation model was used for the primary outcome analysis. Safety was assessed based on adverse events.

RESULTS

Of 34 eligible patients, 20 (mean [standard deviation] age, 53.8 [21.9] years; 12 [60.0%] female) received tocilizumab and 14 received conventional immunotherapy (45.8 [18.0] years; 8 [57.1%] female). The tocilizumab group had greater reduction in MG-ADL score at week 4 (adjusted mean difference, -3.4; 95% CI, -4.7 to -2.0; p < 0.001) than the conventional immunotherapy group, with significant differences sustained through week 24 (adjusted mean difference, -4.5; 95% CI, -6.4 to -2.6; p < 0.001). At week 24, the proportion of patients achieving higher levels of MG-ADL (up to 7-point reduction) and QMG (up to 11-point reduction) scores improvement was significantly greater with tocilizumab. Tocilizumab had acceptable safety profiles without severe or unexpected safety issues.

CONCLUSION

Tocilizumab is safe and effective in improving the MG-ADL score and reducing prednisone dose in refractory AChR-Ab+ gMG, suggesting tocilizumab has the potential to be a valuable therapeutic option for such patients.

MOG Antibody Disease: Nuances in Presentation, Diagnosis, and Management

PURPOSE OF REVIEW

Myelin oligodendrocyte glycoprotein antibody disease (MOGAD) is a distinct neuroinflammatory condition characterized by attacks of optic neuritis, transverse myelitis, and other demyelinating events. Though it can mimic multiple sclerosis and neuromyelitis optica spectrum disorder, distinct clinical and radiologic features which can discriminate these conditions are now recognized. This review highlights recent advances in our understanding of clinical manifestations, diagnosis, and treatment of MOGAD.

RECENT FINDINGS

Studies have identified subtleties of common clinical attacks and identified more rare phenotypes, including cerebral cortical encephalitis, which have broadened our understanding of the clinicoradiologic spectrum of MOGAD and culminated in the recent publication of proposed diagnostic criteria with a familiar construction to those diagnosing other neuroinflammatory conditions. These criteria, in combination with advances in antibody testing, should simultaneously lead to wider recognition and reduced incidence of misdiagnosis. In addition, recent observational studies have raised new questions about when to treat MOGAD chronically, and with which agent. MOGAD pathophysiology informs some of the relatively unique clinical and radiologic features which have come to define this condition, and similarly has implications for diagnosis and management. Further prospective studies and the first clinical trials of therapeutic options will answer several remaining questions about the peculiarities of this condition.

Advancements and prospects of novel biologicals for myasthenia gravis: toward personalized treatment based on autoantibody specificities

Myasthenia gravis (MG) is an antibody-mediated autoimmune disease with a prevalence of 150-250 cases per million individuals. Autoantibodies include long-lived antibodies against the acetylcholine receptor (AChR), mainly of the IgG1 subclass, and IgG4, produced almost exclusively by short-lived plasmablasts, which are prevalent in muscle-specific tyrosine kinase (MuSK) myasthenia gravis. Numerous investigations have demonstrated that MG patients receiving conventional medication today still do not possess satisfactory symptom control, indicating a substantial disease burden. Subsequently, based on the type of the autoantibody and the pathogenesis, we synthesized the published material to date and reached a conclusion regarding the literature related to personalized targeted therapy for MG. Novel agents for AChR MG have shown their efficacy in clinical research, such as complement inhibitors, FcRn receptor antagonists, and B-cell activating factor (BAFF) inhibitors. Rituximab, a representative drug of anti-CD20 therapy, has demonstrated benefits in treatment of MuSK MG patients. Due to the existence of low-affinity antibodies or unidentified antibodies that are inaccessible by existing methods, the treatment for seronegative MG remains complicated; thus, special testing and therapy considerations are necessary. It may be advantageous to initiate the application of novel biologicals at an early stage of the disease. Currently, therapies can also be combined and individualized according to different types of antibodies. With such a wide range of drugs, how to tailor treatment strategies to patients with various conditions and find the most suitable solution for each MG profile are our necessary and urgent aims.

Myelin Oligodendrocyte Glycoprotein-Antibody Associated Disease: An Updated Review of the Clinical Spectrum, Pathogenetic Mechanisms and Therapeutic Management

Clinical syndromes associated with antibodies against myelin oligodendrocyte glycoprotein (MOG) are now recognized as a distinct neurological disease entity, and are gaining increasing attention. The pathogenic mechanisms underlying MOG-antibody disease (MOGAD) remain incompletely understood. Case series, facilitated by registries, and observational studies over the past few years have shed increasing light on the clinical aspects and therapeutic approaches of MOGAD. MOGAD may manifest with a variety of clinical syndromes, including acute disseminated encephalomyelitis (ADEM), autoimmune encephalitis, optic neuritis (ON) and transverse myelitis (TM). MOGAD can be either monophasic or relapsing. This review aims to provide a comprehensive updated description of the clinical spectrum, paraclinical features, and prognosis of MOG-antibody disease, as well as summarize its therapeutic considerations. Randomized clinical trials, standardized diagnostic criteria and treatment guidelines are the steps forward.

Myasthenia Gravis Disease Burden and Its Impact on Satisfaction with Life: A Qualitative Survey of Patients' Perspectives in Japan

INTRODUCTION

Myasthenia gravis (MG) has a negative impact on patients' health-related quality of life; however, many clinicians do not fully understand their patients' lived experience of the disease. To understand the actual conditions of patients with MG and clarify the problems they perceive, we conducted a survey to evaluate the effects of the disease on patients' daily life and work.

METHODS

A questionnaire-based, qualitative, cross-sectional, non-interventional survey was conducted in Japan between April and May 2022 in patients with MG who were receiving regular outpatient treatment. The questionnaire included items regarding the patients' disease characteristics and experience, satisfaction with life, current treatment status, and treatment satisfaction.

RESULTS

In total, 452 patients were included in the survey population (66.6% aged ≥ 60 years; 64.6% with MG disease duration ≥ 10 years; 76.6% acetylcholine receptor [AChR] autoantibody positive). The symptoms of MG had a significant impact on the patients' daily lives, with the most common symptoms being fatigability (74.8%), ptosis (59.7%), diplopia (54.2%), and weakness in the arms and/or legs (50.9%). Patients commonly identified exercise (73.7%), work 68.0%), hobbies (60.4%), travel (60.0%), and socializing with friends (59.7%) as being difficult to perform, with approximately 50% of patients reporting that hospitalization sometimes interfered with their ability to work. In total, 27.2% of patients were dissatisfied with life, with the highest rates of dissatisfaction among patients who were either positive for muscle-specific kinase (MuSK) autoantibodies or seronegative for both AChR and MuSK autoantibodies.

CONCLUSION

In Japanese patients with MG, over 25% are dissatisfied with life, indicating several unmet needs in this population.

Natural IgG protects against early dissemination of vesicular stomatitis virus

Neonatal Fc receptor (FcRn) recycles immunoglobulin G, and inhibition of FcRn is used clinically for treatment of autoimmune diseases. In this work, using the vesicular stomatitis virus (VSV) mouse infection model system, we determined the role of FcRn during virus infection. While induction of neutralizing antibodies and long-term protection of these antibodies was hardly affected in FcRn deficient mice, FcRn deficiency limited the amount of natural IgG (VSV-specific) antibodies. Lack of natural antibodies (nAbs) limited early control of VSV in macrophages, accelerated propagation of virus in several organs, led to the spread of VSV to the neural tissue resulting in fatal outcomes. Adoptive transfer of natural IgG into FcRn deficient mice limited early propagation of VSV in FcRn deficient mice and enhanced survival of FcRn knockout mice. In line with this, vaccination of FcRn mice with very low dose of VSV prior to infection similarly prevented death after infection. In conclusion we determined the importance of nAbs during VSV infection. Lack of FcRn limited nAbs and thereby enhanced the susceptibility to virus infection.

Efficacy, safety and tolerability of rozanolixizumab in patients with chronic inflammatory demyelinating polyradiculoneuropathy: a randomised, subject-blind, investigator-blind, placebo-controlled, phase 2a trial and open-label extension study

BACKGROUND

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a peripheral nerve disorder characterised by weakness and sensory loss. We assessed the neonatal Fc receptor inhibitor rozanolixizumab for CIDP management.

METHODS

CIDP01 (NCT03861481) was a randomised, subject-blind, investigator-blind, placebo-controlled, phase 2a study. Adults with definite or probable CIDP receiving subcutaneous or intravenous immunoglobulin maintenance therapy were randomised 1:1 to 12 once-weekly subcutaneous infusions of rozanolixizumab 10 mg/kg or placebo, stratified according to previous immunoglobulin administration route. Investigators administering treatment and assessing efficacy, and patients, were blinded. The primary outcome was a change from baseline (CFB) to day 85 in inflammatory Rasch-built Overall Disability Scale (iRODS) score. Eligible patients who completed CIDP01 entered the open-label extension CIDP04 (NCT04051944).

RESULTS

In CIDP01, between 26 March 2019 and 31 March 2021, 34 patients were randomised to rozanolixizumab or placebo (17 (50%) each). No significant difference in CFB to day 85 in iRODS centile score was observed between rozanolixizumab (least squares mean 2.0 (SE 3.2)) and placebo (3.4 (2.6); difference -1.5 (90% CI -7.5 to 4.5)). Overall, 14 (82%) patients receiving rozanolixizumab and 13 (76%) receiving placebo experienced a treatment-emergent adverse event during the treatment period. Across CIDP01 and CIDP04, rozanolixizumab was well tolerated over up to 614 days; no clinically meaningful efficacy results were seen. No deaths occurred.

CONCLUSIONS

Rozanolixizumab did not show efficacy in patients with CIDP in this study, although this could be due to a relatively high placebo stability rate. Rozanolixizumab was well tolerated over medium-to-long-term weekly use, with an acceptable safety profile.

Differential effects of FcRn antagonists on the subcellular trafficking of FcRn and albumin

The homeostasis of IgG is maintained by the neonatal Fc receptor, FcRn. Consequently, antagonism of FcRn to reduce endogenous IgG levels is an emerging strategy for treating antibody-mediated autoimmune disorders using either FcRn-specific antibodies or an engineered Fc fragment. For certain FcRn-specific antibodies, this approach has resulted in reductions in the levels of serum albumin, the other major ligand transported by FcRn. Cellular and molecular analyses of a panel of FcRn antagonists have been carried out to elucidate the mechanisms leading to their differential effects on albumin homeostasis. These analyses have identified 2 processes underlying decreases in albumin levels during FcRn blockade: increased degradation of FcRn and competition between antagonist and albumin for FcRn binding. These findings have potential implications for the design of drugs to modulate FcRn function.

Generalized myasthenia gravis with acetylcholine receptor antibodies: A guidance for treatment

BACKGROUND

Generalized myasthenia gravis (MG) with antibodies against the acetylcholine receptor is a chronic disease causing muscle weakness. Access to novel treatments warrants authoritative treatment recommendations. The Nordic countries have similar, comprehensive health systems, mandatory health registers, and extensive MG research.

METHODS

MG experts and patient representatives from the five Nordic countries formed a working group to prepare treatment guidance for MG based on a systematic literature search and consensus meetings.

RESULTS

Pyridostigmine represents the first-line symptomatic treatment, while ambenonium and beta adrenergic agonists are second-line options. Early thymectomy should be undertaken if a thymoma, and in non-thymoma patients up to the age of 50-65 years if not obtaining remission on symptomatic treatment. Most patients need immunosuppressive drug treatment. Combining corticosteroids at the lowest possible dose with azathioprine is recommended, rituximab being an alternative first-line option. Mycophenolate, methotrexate, and tacrolimus represent second-line immunosuppression. Plasma exchange and intravenous immunoglobulin are used for myasthenic crises and acute exacerbations. Novel complement inhibitors and FcRn blockers are effective and fast-acting treatments with promising safety profiles. Their use depends on local availability, refunding policies, and cost-benefit analyses. Adapted physical training is recommended. Planning of pregnancies with optimal treatment, information, and awareness of neonatal MG is necessary. Social support and adaptation of work and daily life activities are recommended.

CONCLUSIONS

Successful treatment of MG rests on timely combination of different interventions. Due to spontaneous disease fluctuations, comorbidities, and changes in life conditions, regular long-term specialized follow-up is needed. Most patients do reasonably well but there is room for further improvement. Novel treatments are promising, though subject to restricted access due to costs.

IL-6 receptor antibody treatment improves muscle weakness in experimental autoimmune myasthenia gravis mouse model

Myasthenia gravis (MG) is a chronic autoimmune disease characterized by muscle weakness and fatigue. It is caused by pathological autoantibodies against components expressed at neuromuscular junctions, such as acetylcholine receptor (AChR). Interleukin-6 (IL-6) has been suggested to play a role in the pathogenesis of MG, and IL-6 receptor (IL-6R) antibody treatment may provide a novel therapeutic option. In this study, we investigated the effects of IL-6R antibody treatment in an experimental autoimmune MG (EAMG) mouse model. We demonstrated that IL-6R antibody treatment improved muscle weakness, reduced IgG deposition at neuromuscular junctions, and the levels of AChR autoantibodies in serum. In addition, follicular helper T cells and Th17, plasma cells in lymph nodes were lower in IL-6R antibody treated mice. Our findings suggest that IL-6R blockade may be a novel and effective therapeutic strategy for the treatment of MG.

The efficacy and safety of FcRn inhibitors in patients with myasthenia gravis: a systematic review and meta-analysis

BACKGROUND

Myasthenia gravis (MG) is an autoimmune disease that causes local or generalized muscle weakness. Complement inhibitors and targeting of the neonatal Fc receptor (FcRn) to block IgG cycling are two novel and successful mechanisms.

METHODS

PubMed, EMBASE, the Cochrane Library, and ClinicalTrials.gov were systematically searched to identify relevant studies published before May 18, 2023. Review Manager 5.3 software was used to assess the data.

RESULTS

We pooled 532 participants from six randomized controlled trials (RCTs). Compared to the placebo, the FcRn inhibitors were more efficacy in Myasthenia Gravis Activities of Daily Living (MG-ADL) (MD = - 1.69 [- 2.35, - 1.03], P < 0.00001), MG-ADL responder (RR = 2.01 [1.62, 2.48], P < 0.00001), Quantitative Myasthenia Gravis (QMG) (MD = - 2.45 [- 4.35, - 0.55], P = 0.01), Myasthenia Gravis Composite (MGC) (MD = - 2.97 [- 4.27, - 1.67], P < 0.00001), 15-item revised version of the Myasthenia Gravis Quality of Life (MGQoL15r) (MD = - 2.52 [- 3.54, - 1.50], P < 0.00001), without increasing the risk of safety. The subgroup analysis showed that efgartigimod was more effective than placebo in MG-ADL responders. Rozanolixizumab was more effective than the placebo except in QMG, and batoclimab was more effective than the placebo except in MG-ADL responder. Nipocalizumab did not show satisfactory efficacy in all outcomes. With the exception of rozanolixizumab, all drugs showed non-inferior safety profiles to placebo.

CONCLUSION

FcRn inhibitors have good efficacy and safety in patients with MG. Among them, efgartigimod and nipocalimab were effective without causing an increased safety risk. Rozanolixizumab, despite its superior efficacy, caused an increased incidence of adverse events. Current evidence does not suggest that nipocalimab is effective in patients with MG.

Recommendations for the management of myasthenia gravis in Belgium

International guidelines on the treatment of myasthenia gravis (MG) have been published but are not tailored to the Belgian situation. This publication presents recommendations from a group of Belgian MG experts for the practical management of MG in Belgium. It includes recommendations for treatment of adult patients with generalized myasthenia gravis (gMG) or ocular myasthenia gravis (oMG). Depending on the MG-related antibody a treatment sequence is suggested with therapies that can be added on if the treatment goal is not achieved. Selection of treatments was based on the level of evidence of efficacy, registration and reimbursement status in Belgium, common daily practice and the personal views and experiences of the authors. The paper reflects the situation in February 2024. In addition to the treatment considerations, other relevant aspects in the management of MG are addressed, including comorbidities, drugs aggravating disease symptoms, pregnancy, and vaccination. As many new treatments might potentially come to market, a realistic future perspective on the impact of these treatments on clinical practice is given. In conclusion, these recommendations intend to be a guide for neurologists treating patients with MG in Belgium.

Exploring the depths of IgG4: insights into autoimmunity and novel treatments

IgG4 subclass antibodies represent the rarest subclass of IgG antibodies, comprising only 3-5% of antibodies circulating in the bloodstream. These antibodies possess unique structural features, notably their ability to undergo a process known as fragment-antigen binding (Fab)-arm exchange, wherein they exchange half-molecules with other IgG4 antibodies. Functionally, IgG4 antibodies primarily block and exert immunomodulatory effects, particularly in the context of IgE isotype-mediated hypersensitivity reactions. In the context of disease, IgG4 antibodies are prominently observed in various autoimmune diseases combined under the term IgG4 autoimmune diseases (IgG4-AID). These diseases include myasthenia gravis (MG) with autoantibodies against muscle-specific tyrosine kinase (MuSK), nodo-paranodopathies with autoantibodies against paranodal and nodal proteins, pemphigus vulgaris and foliaceus with antibodies against desmoglein and encephalitis with antibodies against LGI1/CASPR2. Additionally, IgG4 antibodies are a prominent feature in the rare entity of IgG4 related disease (IgG4-RD). Intriguingly, both IgG4-AID and IgG4-RD demonstrate a remarkable responsiveness to anti-CD20-mediated B cell depletion therapy (BCDT), suggesting shared underlying immunopathologies. This review aims to provide a comprehensive exploration of B cells, antibody subclasses, and their general properties before examining the distinctive characteristics of IgG4 subclass antibodies in the context of health, IgG4-AID and IgG4-RD. Furthermore, we will examine potential therapeutic strategies for these conditions, with a special focus on leveraging insights gained from anti-CD20-mediated BCDT. Through this analysis, we aim to enhance our understanding of the pathogenesis of IgG4-mediated diseases and identify promising possibilities for targeted therapeutic intervention.

[Myasthenia gravis-Gender aspects and family planning]

BACKGROUND

There is evidence that gender-specific differences can influence the diagnostics, treatment and long-term disease course of myasthenia gravis (MG). In women the diagnosis is often made during childbearing age.

OBJECTIVE

Gender-specific differences in MG and relevant aspects in routine clinical practice are presented. In addition, current studies on family planning, pregnancy and childbirth in MG are highlighted and treatment recommendations are derived.

MATERIAL AND METHODS

Narrative literature review.

RESULTS

In addition to sociodemographic data, gender-specific differences encompass clinical as well as paraclinical factors, such as disease severity and antibody status. With few exceptions pregnancy is possible with good maternal and neonatal outcome. During pregnancy and peripartum, children of MG patients should be closely monitored for early detection and treatment of potential syndromes caused by diaplacental transfer of maternal antibodies.

CONCLUSION

Gender-specific factors can influence the course of MG. Adequate medical counselling and multidisciplinary collaboration are essential for MG patients who wish to have children.

Structure and function of therapeutic antibodies approved by the US FDA in 2023

In calendar year 2023, the United States Food and Drug Administration (US FDA) approved a total of 55 new molecular entities, of which 12 were in the class of therapeutic antibodies. Besides antibody protein drugs, the US FDA also approved another five non-antibody protein drugs, making the broader class of protein drugs about 31% of the total approved drugs. Among the 12 therapeutic antibodies approved by the US FDA, 8 were relatively standard IgG formats, 3 were bivalent, bispecific antibodies and 1 was a trivalent, bispecific antibody. In 2023, no new antibody-drug conjugates, immunocytokines or chimeric antigen receptor-T cells were approved. Of the approved antibodies, two targeted programmed cell death receptor-1 (PD-1) for orphan indications, two targeted CD20 for diffuse large B cell lymphoma, two targeted different receptors (B-cell maturation antigen [BCMA] and G-coupled protein receptor class C, group 5, member D [GPRC5D]) for treatment of multiple myeloma, and one each that targeted amyloid-β protofibrils for Alzheimer's disease, neonatal Fc receptor alpha-chain for myasthenia gravis, complement factor C5 for CD55 deficiency with hyper-activation of complement, angiopathic thrombosis and severe protein-losing enteropathy disease, interleukin (IL)-23p19 for severely active ulcerative colitis, IL-17A-F for plaque psoriasis and respiratory syncytial virus (RSV)-F protein for season-long RSV prophylaxis in infants.

[Myasthenia Gravis - Update]

Myasthenia gravis - still a challenge for sufferers and doctors in 2023. But which therapy is best suited? Our clinically experienced experts have summarized the current guidelines for diagnosis and treatment in order to provide optimal support for those affected. Find out how you can carry out a quick and targeted diagnosis and which treatment options are available to alleviate the course of the disease.

Rozanolixizumab: A New Therapy in the Treatment of Myasthenia Gravis

OBJECTIVE

The aims of this article are to review the clinical aspects of rozanolixizumab, to describe clinical trial results that led to the drug's approval, and to examine the impact on patient care to aid clinical decision making.

DATA SOURCES

A PubMed search was conducted using the terms Rystiggo™, rozanolixizumab, rozanolixizumab therapy, and myasthenia gravis. The most recent prescribing information was also used for information relating to the drug and for identification of pertinent studies.

STUDY SELECTION/DATA EXTRACTION

Phase I, II, and III randomized controlled trials were all eligible for inclusion. Meeting abstracts and articles focusing on the use of rozanolixizumab or any indication other than generalized myasthenia gravis were excluded from this article.

DATA SYNTHESIS

Food and Drug Administration approval of rozanolixizumab is based on the phase III MycarinG study in patients with generalized myasthenia gravis. A phase II trial explored initial clinical efficacy and safety pertaining to the dose and frequency of rozanolixizumab across 2 treatment periods in patients with moderate to severe myasthenia gravis.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE IN COMPARISON TO EXISTING AGENTS

Rozanolixizumab is the first therapy approved to treat patients positive for both types of antibodies, anti-acetylcholine receptor or anti-muscle-specific tyrosine kinase, in generalized myasthenia gravis.

CONCLUSION/RELEVANCE

The approval of rozanolixizumab represents an advancement in therapy for generalized myasthenia gravis. The provision of individualized, targeted, and well-tolerated treatment is valuable for the patients whose myasthenia gravis is not well controlled and who are seeking a medication with a rapid onset of action to improve their symptoms and overall quality of life.

Expert consensus recommendations for improving and standardising the assessment of patients with generalised myasthenia gravis

BACKGROUND

Regular and consistent disease assessment could provide a clearer picture of burden in generalised myasthenia gravis (gMG) and improve patient care; however, the use of assessment tools in practice lacks standardisation. This modified Delphi approach was taken to review current evidence on assessment tool use in gMG and develop expert-derived consensus recommendations for good practice.

METHODS

A European expert panel of 15 experienced gMG neurologists contributed to development of this consensus, four of whom formed a lead Sub-committee. The PICO (Population, Intervention, Control, Outcomes) framework was used to define six clinical questions on gMG assessment tools, a systematic literature review was conducted, and evidence-based statements were developed. According to a modified Delphi voting process, consensus was reached when ≥70% of the experts rated agreement with a statement as ≥8 on a scale of 1-10.

RESULTS

Eighteen expert- and evidence-based consensus statements based on six themes were developed. Key recommendations include: consistent use of the Myasthenia Gravis Activities of Daily Living score (MG-ADL) across clinical settings, followed by a simple question (e.g., Patient Acceptable Symptom State [PASS]) or scale to determine patient satisfaction in clinical practice; use of a Quantitative Myasthenia Gravis [QMG] or quality of life [QoL] assessment when the MG-ADL indicates disease worsening; and consideration of symptom state to determine the timing and frequency of recommended assessments. Expert panel consensus was reached on all 18 statements after two voting rounds.

CONCLUSIONS

This process provided evidence- and expert consensus-based recommendations for the use of objective and subjective assessment tools across gMG research and care to improve management and outcomes for patients.

The ClC-1 chloride channel inhibitor NMD670 improves skeletal muscle function in rat models and patients with myasthenia gravis

Myasthenia gravis (MG) is a neuromuscular disease that results in compromised transmission of electrical signals at the neuromuscular junction (NMJ) from motor neurons to skeletal muscle fibers. As a result, patients with MG have reduced skeletal muscle function and present with symptoms of severe muscle weakness and fatigue. ClC-1 is a skeletal muscle specific chloride (Cl-) ion channel that plays important roles in regulating neuromuscular transmission and muscle fiber excitability during intense exercise. Here, we show that partial inhibition of ClC-1 with an orally bioavailable small molecule (NMD670) can restore muscle function in rat models of MG and in patients with MG. In severely affected MG rats, ClC-1 inhibition enhanced neuromuscular transmission, restored muscle function, and improved mobility after both single and prolonged administrations of NMD670. On this basis, NMD670 was progressed through nonclinical safety pharmacology and toxicology studies, leading to approval for testing in clinical studies. After successfully completing phase 1 single ascending dose in healthy volunteers, NMD670 was tested in patients with MG in a randomized, placebo-controlled, single-dose, three-way crossover clinical trial. The clinical trial evaluated safety, pharmacokinetics, and pharmacodynamics of NMD670 in 12 patients with mild MG. NMD670 had a favorable safety profile and led to clinically relevant improvements in the quantitative myasthenia gravis (QMG) total score. This translational study spanning from single muscle fiber recordings to patients provides proof of mechanism for ClC-1 inhibition as a potential therapeutic approach in MG and supports further development of NMD670.

Batoclimab vs Placebo for Generalized Myasthenia Gravis: A Randomized Clinical Trial

Importance

Myasthenia gravis (MG) is caused by autoantibodies that disrupt the neuromuscular junction. The neonatal fragment crystallizable receptor (FcRn) antagonists, efgartigimod and rozanolixizumab, reduce immunoglobulin G (IgG) level in the circulation and alleviate symptoms in patients with generalized MG.

Objective

To examine the efficacy and safety profile of batoclimab, a monoclonal IgG1 antibody, in patients with generalized MG.

Design, Setting, and Participants

This was a multicenter randomized clinical trial conducted from September 15, 2021, to June 29, 2022, at 27 centers in China. Adult patients 18 years or older with generalized MG were screened, and those who were antibody positive were enrolled.

Intervention

Eligible patients received batoclimab or matching placebo in addition to standard of care. Each treatment cycle consisted of 6 weekly subcutaneous injections of batoclimab, 680 mg, or matching placebo followed by 4 weeks of observation. A second treatment cycle was conducted in patients who required continuing treatment.

Main Outcome and Measure

The primary outcome was sustained improvement, as defined by a 3-point or greater reduction in the Myasthenia Gravis Activities of Daily Living (MG-ADL) score from baseline for 4 or more consecutive weeks in the first cycle in individuals who were positive for acetylcholine receptor or muscle-specific kinase antibodies.

Results

A total of 178 adult patients with generalized MG were screened, 132 were randomly assigned, 131 tested positive for antibodies, and 1 tested negative for antibodies. A total of 132 patients (mean [SE] age, 43.8 [13.6] years; 88 women [67.2%]) were enrolled. The rate of sustained MG-ADL improvement in the first cycle in antibody-positive patients was 31.3% (20 of 64) in the placebo group vs 58.2% (39 of 67) in the batoclimab group (odds ratio, 3.45; 95% CI, 1.62-7.35; P = .001). The MG-ADL score diverged between the 2 groups as early as week 2. The mean (SE) maximum difference in MG-ADL score reduction occurred 1 week after the last dose (day 43, 1.7 [0.3] in the placebo group vs 3.6 [0.3] in the batoclimab group; group difference, -1.9; 95% CI, -2.8 to -1.0; nominal P < .001). The rates of treatment-related and severe treatment-emergent adverse events in patients were 36.9% (24 of 65) and 7.7% (5 of 65) in the placebo group vs 70.1% (47 of 67) and 3.0% (2 of 67) in the batoclimab group, respectively.

Conclusions and Relevance

Batoclimab increased the rate of sustained MG-ADL improvement and was well tolerated in adult patients with generalized MG. Clinical effects and the extent of IgG reduction were similar to those previously reported for efgartigimod and rozanolixizumab. Future studies of large sample size are needed to further understand the safety profile of batoclimab.

Trial Registration

ClinicalTrials.gov Identifier: NCT05039190.

Promising therapies for the treatment of myasthenia gravis

INTRODUCTION

Myasthenia gravis (MG) is an autoimmune condition targeting the neuromuscular junction, which manifests with neuromuscular symptoms of varying severity and significant morbidity. The mainstay of treatment in MG is mitigation of the immune cascade with steroids and non-steroidal immunosuppressive therapies. The therapeutic strategies in MG are transitioning from broad and indiscriminate immunosuppression to novel agents targeting key steps in MG pathogenesis, including T cell activation, B cell proliferation, complement activation, maintenance of pathogenic antibody production, and proinflammatory cytokine production.

AREAS COVERED

In this review, an overview of the pathogenesis of MG and traditional MG therapies is presented, followed by a discussion of the novel MG drugs that have been evaluated in phase 3 clinical trials with an emphasis on those which have received regulatory approval.

EXPERT OPINION

Novel MG therapeutics belonging to the classes of complement inhibitors, neonatal Fc receptor (FcRn) inhibitors and B cell depletors, as well as the other emerging MG drugs in the pipeline constitute promising treatment strategies with potentially better efficacy and safety compared to the conventional MG treatments. However, further long-term research is needed in order to optimize the implementation of these new treatment options for the appropriate patient populations.

Comparative effectiveness of azathioprine and mycophenolate mofetil for myasthenia gravis (PROMISE-MG): a prospective cohort study

BACKGROUND

Myasthenia gravis is an autoimmune disorder of the neuromuscular junction. Treatment typically includes symptomatic oral cholinesterase inhibitors, immunosuppression, and immunomodulation. In addition to corticosteroids, azathioprine and mycophenolate mofetil are the most frequently used immunosuppressants in North America. We aimed to evaluate the comparative effectiveness of these two drugs, and to assess the effect of the dose and duration of treatment.

METHODS

We did a prospective cohort study at 19 academic centres in Canada and the USA. We included patients (aged ≥18 years) with autoimmune myasthenia gravis, who were never treated with immunosuppressants. Treating clinicians determined the choice of medication, dose, follow-up intervals, and drug monitoring. Outcome measures and adverse events were recorded at each visit. We assessed two co-primary outcomes. The first was the patient-reported Myasthenia Gravis-Quality of Life 15-revised (MGQOL-15r) score, measured as the mean change from treatment initiation to the follow-up visit with the lowest score. A clinically meaningful reduction (CMR) in MGQOL-15r was defined as a 5-point decrease. The second was a composite clinical outcome of disease improvement (Myasthenia Gravis Foundation of America Post-Intervention Status Minimal Manifestations or better) and low adverse event burden (defined as grade ≤1 Common Terminology Criteria for Adverse Events). We also compared these outcomes in patients receiving an adequate dose and duration of azathioprine (≥2 mg/kg per day for at least 12 months) or mycophenolate mofetil (≥2 g per day for at least 8 months) and a lower dose or shorter duration of these agents. We used propensity score weighting with generalised linear regression models. This study is registered with ClinicalTrials.gov (NCT03490539).

FINDINGS

Between May 1, 2018, and Aug 31, 2020, 167 patients were enrolled; 85 did not receive azathioprine or mycophenolate mofetil and were excluded. Four were excluded from outcome analyses because they had scores of 0 on an outcome measure at treatment initiation. Of the 78 patients included in analyses, 47 received mycophenolate mofetil (median follow-up 25 months [IQR 13·5-31·5]) and 31 received azathioprine (median follow-up 20 months [IQR 13-30]). The mean change in MG-QOL15r was -10·4 (95% CI -18·9 to -1·3) with mycophenolate mofetil and -6·8 (-17·2 to 3·6) with azathioprine (mean difference -3·3, 95% CI -7·7 to 1·2; p=0·15). 38 (81%) of 47 patients receiving mycophenolate mofetil and 18 (57%) of 31 receiving azathioprine had a CMR in MG-QOL15r (risk difference 24·0%; 95% CI -0·2 to 48·0; p=0·052). The clinical composite outcome was achieved in 22 (47·7%) of 47 patients who received mycophenolate mofetil and nine (28·1%) of 31 who received azathioprine (risk difference 19·6%, 95% CI -4·9 to 44·2; p=0·12). Descriptive analysis did not find a difference in the proportion of patients reaching a CMR in MG-QOL15r between the adequate dose and duration group and the lower dose or shorter duration group. Adverse events occurred in 11 (32%) of 34 patients who received azathioprine and nine (19%) of 48 who received mycophenolate mofetil. The most frequent adverse events were hepatotoxicity with azathioprine (five [15%] of 34) and gastrointestinal disturbances (seven [15%] of 48) with mycophenolate mofetil. There were no study-related deaths.

INTERPRETATION

More than half of patients treated with azathioprine and mycophenolate mofetil felt their quality of life improved; no difference in clinical outcomes was noted between the two drugs. Adverse events associated with azathioprine were potentially more serious than those with mycophenolate mofetil, although mycophenolate mofetil is teratogenic. Lower than recommended doses of azathioprine might be effective, with reduced dose-dependent adverse events. More comparative effectiveness studies are required to inform treatment choices in myasthenia gravis.

FUNDING

Patient-Centered Outcomes Research Institute, Myasthenia Gravis Foundation of America.

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.

Pharmacokinetics and pharmacodynamics across infusion rates of intravenously administered nipocalimab: results of a phase 1, placebo-controlled study

Introduction

Nipocalimab is a high-affinity, fully human, aglycosylated, effectorless, immunoglobulin G (IgG) 1 monoclonal antibody that targets the neonatal Fc receptor (FcRn), decreases systemic IgG including autoantibodies, and is under development in several IgG autoantibody- and alloantibody-mediated diseases, including generalized myasthenia gravis, chronic inflammatory demyelinating polyneuropathy, maternal-fetal medicine, and multiple other therapeutic areas. An initial phase 1 study with single and multiple ascending doses of nipocalimab infused intravenously (IV) over 2 h demonstrated dose-dependent serum pharmacokinetics and IgG reductions, with an adverse event (AE) profile comparable to placebo.

Methods

The current investigation evaluates the safety, tolerability, pharmacokinetics, and pharmacodynamics of single doses of nipocalimab across various IV infusion rates in a randomized, double-blind, placebo-controlled, sequential-dose study. Forty participants were randomized to receive nipocalimab 30 mg/kg over 60, 30, 15 or 7.5 min (0.5, 1, 2, or 4 mg/kg/min); nipocalimab 60 mg/kg over 15 min (4 mg/kg/min); or matching placebo.

Results

At doses up to 60 mg/kg and infusion rates up to 4 mg/kg/min (maximum clinically feasible rate), single doses of nipocalimab were tolerable, with 12 (40%) participants experiencing AEs across nipocalimab cohorts compared with 1 (10%) participant in the placebo cohort. AEs deemed treatment related occurred in 6 (20%) participants receiving nipocalimab and 1 (10%) participant receiving placebo. None of the AEs were severe, and no participants discontinued treatment due to AEs. Nipocalimab provided consistent, dose-dependent serum pharmacokinetics and IgG reductions, regardless of infusion rate.

Discussion

This study supports the use of shortened durations of nipocalimab infusion for future studies.

Registered trials on novel therapies for myasthenia gravis: a cross-sectional study on ClinicalTrials.gov

Novel biologics in MG therapy research is on the rise. This research aimed to investigate the characteristics of registered trials on novel therapies for myasthenia gravis on ClinicalTrials.gov. This cross-sectional study used a descriptive approach to assess the features of the included trials on ClinicalTrials.gov. We found 62 registered trials from 2007 to 2023 on ClinicalTrials.gov. The results showed a yearly rise in the number of registered trials (r = 0.76, p < 0.001). Following 2017, more industry-sponsored trials were conducted (91.5% [43] vs. 60% [9], p = 0.009), fewer results were released (10.6% [5] vs. 60% [9], p = 0.001), and more trials entered phase 3 (67.4% [31] vs. 20% [2], p = 0.001). The most researched novel medications were neonatal Fc receptor inhibitors (51.2% [21]), complement inhibitors (39.0% [16]), and B cell depletors (14.6% [6]). According to the website's data, the neonatal Fc receptor inhibitors and complement inhibitors were effective in treating myasthenia gravis patients in three trials (NCT03315130, NCT03669588, and NCT00727194). This study provides valuable insights into the profile of registered trials on novel therapies for myasthenia gravis. More clinical studies are needed in the future to prove the value of its application.

Safety and Efficacy of Nipocalimab in Patients With Generalized Myasthenia Gravis: Results From the Randomized Phase 2 Vivacity-MG Study

BACKGROUND AND OBJECTIVES

To evaluate in a phase 2 study the safety and efficacy of IV nipocalimab, a fully human, antineonatal Fc receptor monoclonal antibody, in patients with generalized myasthenia gravis (gMG).

METHODS

Patients with gMG with inadequate response to stable standard-of-care (SOC) therapy were randomized 1:1:1:1:1 to receive either IV placebo every 2 weeks (Q2W) or one of 4 IV nipocalimab treatments: 5 mg/kg once every 4 weeks (Q4W), 30 mg/kg Q4W, 60 mg/kg Q2W each for 8 weeks, or a 60 mg/kg single dose, in addition to their background SOC therapy. Infusions (placebo or nipocalimab) were Q2W in all groups to maintain blinding. The primary safety endpoint was incidence of treatment-emergent adverse events (TEAEs), including serious adverse events and adverse events of special interest. The primary efficacy endpoint was change from baseline to day 57 in Myasthenia Gravis-Activities of Daily Living (MG-ADL) total scores. Dose response of change at day 57 was analyzed with a linear trend test over the placebo, nipocalimab 5 mg/kg Q4W, nipocalimab 30 mg/kg Q4W, and nipocalimab 60 mg/kg Q2W groups.

RESULTS

Sixty-eight patients (nipocalimab: n = 54; placebo, n = 14) were randomized; 64 patients (94.1%) were positive for antiacetylcholine receptor autoantibodies, and 4 patients (6%) were positive for antimuscle-specific tyrosine kinase autoantibodies. Fifty-seven patients (83.8%) completed treatment through day 57. The combined nipocalimab group compared with the placebo group demonstrated similar incidences of TEAEs (83.3% vs 78.6%, respectively) and infections (33.3% vs 21.4%, respectively). No deaths or discontinuations due to TEAEs and no TEAEs of special interest (grade ≥3 infection or hypoalbuminemia) were observed with nipocalimab treatment. A statistically significant dose response was observed for change from baseline in MG-ADL at day 57 (p = 0.031, test of linear trend).

DISCUSSION

Nipocalimab was generally safe, well-tolerated, and showed evidence of dose-dependent reduction in MG-ADL scores at day 57 in this phase 2 study. These results support further evaluation of nipocalimab for the treatment of gMG.

TRIAL REGISTRATION INFORMATION

Clinical Trials Registration: NCT03772587; first submitted December 10, 2018; EudraCT Number: 2018-002247-28; first submitted November 30, 2018; date of first patient dosed April 10, 2019.

CLASSIFICATION OF EVIDENCE

This study provides Class I evidence that for patients with gMG, nipocalimab was well-tolerated, and it did not significantly improve MG-ADL at any individual dose but demonstrated a significant dose response for improved MG-ADL across doses.

Interactions of the anti-FcRn monoclonal antibody, rozanolixizumab, with Fcγ receptors and functional impact on immune cells in vitro

Rozanolixizumab is a humanized anti-neonatal Fc receptor (FcRn) monoclonal antibody (mAb) of the immunoglobulin G4 (IgG4) sub-class, currently in clinical development for the treatment of IgG autoantibody-driven diseases. This format is frequently used for therapeutic mAbs due to its intrinsic lower affinity for Fc gamma receptors (FcγR) and lack of C1q engagement. However, with growing evidence suggesting that no Fc-containing agent is truly "silent" in this respect, we explored the engagement of FcγRs and potential functional consequences with rozanolixizumab. In the study presented here, rozanolixizumab was shown to bind to FcγRs in both protein-protein and cell-based assays, and the kinetic data were broadly as expected based on published data for an IgG4 mAb. Rozanolixizumab was also able to mediate antibody bipolar bridging (ABB), a phenomenon that led to a reduction of labeled FcγRI from the surface of human macrophages in an FcRn-dependent manner. However, the presence of exogenous human IgG, even at low concentrations, was able to prevent both binding and ABB events. Furthermore, data from in vitro experiments using relevant human cell types that express both FcRn and FcγRI indicated no evidence for functional sequelae in relation to cellular activation events (e.g., intracellular signaling, cytokine production) upon either FcRn or FcγR binding of rozanolixizumab. These data raise important questions about whether therapeutic antagonistic mAbs like rozanolixizumab would necessarily engage FcγRs at doses typically administered to patients in the clinic, and hence challenge the relevance and interpretation of in vitro assays performed in the absence of competing IgG.

Healthcare resource utilization, costs and treatment associated with myasthenia gravis exacerbations among patients with myasthenia gravis in the USA: a retrospective analysis of claims data

Aim: There are limited data on the clinical and economic burden of exacerbations in patients with myasthenia gravis (MG). We assessed patient clinical characteristics, treatments and healthcare resource utilization (HCRU) associated with MG exacerbation. Patients & methods: This was a retrospective analysis of adult patients with MG identified by commercial, Medicare or Medicaid insurance claims from the IBM® MarketScan® database. Eligible patients had two or more MG diagnosis codes, without evidence of exacerbation or crisis in the baseline period (12 months prior to index [first eligible MG diagnosis]). Clinical characteristics were evaluated at baseline and 12 weeks before each exacerbation. Number of exacerbations, MG treatments and HCRU costs associated with exacerbation were described during a 2-year follow-up period. Results: Among 9352 prevalent MG patients, 34.4% (n = 3218) experienced ≥1 exacerbation after index: commercial, 53.0% (n = 1706); Medicare, 39.4% (n = 1269); and Medicaid, 7.6% (n = 243). During follow-up, the mean (standard deviation) number of exacerbations per commercial and Medicare patient was 3.7 (7.0) and 2.7 (4.1), respectively. At least two exacerbations were experienced by approximately half of commercial and Medicare patients with ≥1 exacerbation. Mean total MG-related healthcare costs per exacerbation ranged from $26,078 to $51,120, and from $19,903 to $49,967 for commercial and Medicare patients, respectively. AChEI use decreased in patients with multiple exacerbations, while intravenous immunoglobulin use increased with multiple exacerbations. Conclusion: Despite utilization of current treatments for MG, MG exacerbations are associated with a high clinical and economic burden in both commercial and Medicare patients. Additional treatment options and improved disease management may help to reduce exacerbations and disease burden.

Myasthenia Gravis Treatment: From Old Drugs to Innovative Therapies with a Glimpse into the Future

Myasthenia gravis (MG) is a rare autoimmune disease that causes debilitating muscle weakness due to impaired neuromuscular transmission. Since most (about 80-90%) MG patients present autoantibodies against the acetylcholine receptor, standard medical therapy consists of symptomatic treatment with acetylcholinesterase inhibitors (e.g., pyridostigmine). In addition, considering the autoimmune basis of MG, standard therapy includes immunomodulating agents, such as corticosteroids, azathioprine, cyclosporine A, and cyclophosphamide. New strategies have been proposed for the treatment of MG and include complement blockade (i.e., eculizumab, ravulizumab, and zilucoplan) and neonatal Fc receptor antagonism (i.e., efgartigimod and rozanolixizumab). The aim of this review is to provide a detailed overview of the pre- and post-marketing evidence on the five pharmacological treatments most recently approved for the treatment of MG, by identifying both preclinical and clinical studies registered in clinicaltrials.gov. A description of the molecules currently under evaluation for the treatment of MG is also provided.

Therapeutic Plasma Exchange Versus FcRn Inhibition in Autoimmune Disease

Therapeutic plasma exchange (TPE or PLEX) is used in a broad range of autoimmune diseases, with the goal of removing autoantibodies from the circulation. A newer approach for the selective removal of immunoglobulin G (IgG) antibodies is the use of therapeutic molecules targeting the neonatal Fc receptor (FcRn). FcRn regulates IgG recycling, and its inhibition results in a marked decrease in circulating autoantibodies of the IgG subtype. The difference between FcRn inhibition and PLEX is often questioned. With anti-FcRn monoclonal antibodies (mAbs) and fragments only recently entering this space, limited data are available regarding long-term efficacy and safety. However, the biology of FcRn is well understood, and mounting evidence regarding the efficacy, safety, and potential differences among compounds in development is available, allowing us to compare against nonselective plasma protein depletion methods such as PLEX. FcRn inhibitors may have distinct advantages and disadvantages over PLEX in certain scenarios. Use of PLEX is preferred over FcRn inhibition where removal of antibodies other than IgG or when concomitant repletion of missing plasma proteins is needed for therapeutic benefit. Also, FcRn targeting has not yet been studied for use in acute flares or crisis states of IgG-mediated diseases. Compared with PLEX, FcRn inhibition is associated with less invasive access requirements, more specific removal of IgG versus other immunoglobulins without a broad impact on circulating proteins, and any impacts on other therapeutic drug levels are restricted to other mAbs. In addition, the degree of IgG reduction is similar with FcRn inhibitors compared with that afforded by PLEX. Here we describe the scientific literature regarding the use of PLEX and FcRn inhibitors in autoimmune diseases and provide an expert discussion around the potential benefits of these options in varying clinical conditions and scenarios.

Monoclonal antibody therapies for aquaporin-4-immunoglobulin G-positive neuromyelitis optica spectrum disorder and myelin oligodendrocyte glycoprotein antibody-associated disease

Monoclonal antibody therapies mark the new era of targeted treatment for relapse prevention in aquaporin-4 (AQP4)-immunoglobulin G (IgG)-positive neuromyelitis optica spectrum disorder (AQP4-IgG+NMOSD). For over a decade, rituximab, an anti-CD20 B-cell-depleting agent, had been the most effectiveness treatment for AQP4-IgG+NMOSD. Tocilizumab, an anti-interleukin-6 receptor, was also observed to be effective. In 2019, several randomized, placebo-controlled trials were completed that demonstrated the remarkable efficacy of eculizumab (anti-C5 complement inhibitor), inebilizumab (anti-CD19 B-cell-depleting agent), and satralizumab (anti-interleukin-6 receptor), leading to the Food and Drug Administration (FDA) approval of specific treatments for AQP4-IgG+NMOSD for the first time. Most recently, ravulizumab (anti-C5 complement inhibitor) was also shown to be highly efficacious in an open-label, external-controlled trial. Although only some patients with myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) warrant immunotherapy, there is currently no FDA-approved treatment for relapse prevention in MOGAD. Observational studies showed that tocilizumab was associated with a decrease in relapses, whereas rituximab seemed to have less robust effectiveness in MOGAD compared to AQP4-IgG+NMOSD. Herein, we review the evidence on the efficacy and safety of each monoclonal antibody therapy used in AQP4-IgG+NMOSD and MOGAD, including special considerations in children and women of childbearing potential.

Exploiting the neonatal crystallizable fragment receptor to treat kidney disease

The neonatal Fc receptor (FcRn) was initially discovered as the receptor that allowed passive immunity in newborns by transporting maternal IgG through the placenta and enterocytes. Since its initial discovery, FcRn has been found to exist throughout all stages of life and in many different cell types. Beyond passive immunity, FcRn is necessary for intrinsic albumin and IgG recycling and is important for antigen processing and presentation. Given its multiple important roles, FcRn has been utilized in many disease treatments including a new class of agents that were developed to inhibit FcRn for treatment of a variety of autoimmune diseases. Certain cell populations within the kidney also express high levels of this receptor. Specifically, podocytes, proximal tubule epithelial cells, and vascular endothelial cells have been found to utilize FcRn. In this review, we summarize what is known about FcRn and its function within the kidney. We also discuss how FcRn has been used for therapeutic benefit, including how newer FcRn inhibiting agents are being used to treat autoimmune diseases. Lastly, we will discuss what renal diseases may respond to FcRn inhibitors and how further work studying FcRn within the kidney may lead to therapies for kidney diseases.

Guideline for the management of myasthenic syndromes

Myasthenia gravis (MG), Lambert-Eaton myasthenic syndrome (LEMS), and congenital myasthenic syndromes (CMS) represent an etiologically heterogeneous group of (very) rare chronic diseases. MG and LEMS have an autoimmune-mediated etiology, while CMS are genetic disorders. A (strain dependent) muscle weakness due to neuromuscular transmission disorder is a common feature. Generalized MG requires increasingly differentiated therapeutic strategies that consider the enormous therapeutic developments of recent years. To include the newest therapy recommendations, a comprehensive update of the available German-language guideline 'Diagnostics and therapy of myasthenic syndromes' has been published by the German Neurological society with the aid of an interdisciplinary expert panel. This paper is an adapted translation of the updated and partly newly developed treatment guideline. It defines the rapid achievement of complete disease control in myasthenic patients as a central treatment goal. The use of standard therapies, as well as modern immunotherapeutics, is subject to a staged regimen that takes into account autoantibody status and disease activity. With the advent of modern, fast-acting immunomodulators, disease activity assessment has become pivotal and requires evaluation of the clinical course, including severity and required therapies. Applying MG-specific scores and classifications such as Myasthenia Gravis Activities of Daily Living, Quantitative Myasthenia Gravis, and Myasthenia Gravis Foundation of America allows differentiation between mild/moderate and (highly) active (including refractory) disease. Therapy decisions must consider age, thymic pathology, antibody status, and disease activity. Glucocorticosteroids and the classical immunosuppressants (primarily azathioprine) are the basic immunotherapeutics to treat mild/moderate to (highly) active generalized MG/young MG and ocular MG. Thymectomy is indicated as a treatment for thymoma-associated MG and generalized MG with acetylcholine receptor antibody (AChR-Ab)-positive status. In (highly) active generalized MG, complement inhibitors (currently eculizumab and ravulizumab) or neonatal Fc receptor modulators (currently efgartigimod) are recommended for AChR-Ab-positive status and rituximab for muscle-specific receptor tyrosine kinase (MuSK)-Ab-positive status. Specific treatment for myasthenic crises requires plasmapheresis, immunoadsorption, or IVIG. Specific aspects of ocular, juvenile, and congenital myasthenia are highlighted. The guideline will be further developed based on new study results for other immunomodulators and biomarkers that aid the accurate measurement of disease activity.

Ravulizumab in Myasthenia Gravis: A Review of the Current Evidence

The terminal complement C5 inhibitor ravulizumab was engineered from the humanized monoclonal antibody eculizumab to have an extended half-life and duration of action. It binds to human terminal complement protein C5, inhibiting its cleavage into C5a and C5b, thus preventing the cascade of events that lead to architectural destruction of the postsynaptic neuromuscular junction membrane by the membrane attack complex, and consequent muscle weakness in patients with anti-acetylcholine receptor (AChR) antibody-positive generalized myasthenia gravis (gMG). The 26-week randomized, placebo-controlled period (RCP) of the phase 3 CHAMPION MG study demonstrated the rapid efficacy of ravulizumab in reducing MG symptoms. Weight-based dosing of ravulizumab every 8 weeks provided sustained efficacy, in terms of patient-reported (Myasthenia Gravis-Activities of Daily Living) and clinician-reported (Quantitative Myasthenia Gravis) endpoints in patients with anti-AChR antibody-positive gMG. Pharmacokinetic and pharmacodynamic analyses showed therapeutic serum ravulizumab concentrations (>175 µg/mL) were achieved immediately after the first dose and were maintained throughout 26 weeks, irrespective of patient body weight; inhibition of serum free C5 was immediate, complete (<0.5 μg/mL), and sustained in all patients. Interim results from the open-label extension (OLE) showed that after 60 weeks, efficacy was maintained in patients continuing on ravulizumab. Rapid and sustained improvements in efficacy, similar to those seen in patients initiating ravulizumab in the RCP, were observed after initiation of ravulizumab treatment in patients who switched from placebo in the RCP to ravulizumab in the OLE. The findings from the RCP and OLE support ravulizumab's favorable safety profile. In conclusion, ravulizumab has a simple weight-based administration and long dosing interval. Its targeted mechanism of action without generalized immunosuppression is reflected in its rapid onset of symptom improvement, sustained efficacy and good safety profile in the treatment of patients with anti-AChR antibody-positive gMG.

What Is in the Neuromuscular Junction Literature?

ABSTRACT

This update covers several articles on diagnosis and misdiagnosis of myasthenia gravis (MG), the role of complement in MG, and then an impressive number of recent treatment trials. There is a negative study on any corticosteroid-sparing effect of intravenous immunoglobulin. A number of positive studies are reviewed. Open-label extension studies of phase 3 trials showed benefit regarding quality of life with efgartigimod and in functional measures with ravulizumab. The phase 3 RAISE trial of zilucoplan, a self-administered complement C5 inhibitor, is covered as well as the MyCarinG trial of rozanolixizumab. The notion of using fast-acting therapies early in the course of MG is addressed. The last sections center on MG and Lambert-Eaton myasthenic syndrome as a consequence of immune checkpoint inhibitor therapy.

Delving into Molecular Pathways: Analyzing the Mechanisms of Action of Monoclonal Antibodies Integrated in IMGT/mAb-DB for Myasthenia Gravis

BACKGROUND

Myasthenia Gravis (MG) is a rare autoimmune disease presenting with auto-antibodies that affect the neuromuscular junction. In addition to symptomatic treatment options, novel therapeutics include monoclonal antibodies (mAbs). IMGT®, the international ImMunoGeneTics information system®, extends the characterization of therapeutic antibodies with a systematic description of their mechanisms of action (MOA) and makes them available through its database for mAbs and fusion proteins, IMGT/mAb-DB.

METHODS

Using available literature data combined with amino acid sequence analyses from mAbs managed in IMGT/2Dstructure-DB, the IMGT® protein database, biocuration allowed us to define in a standardized way descriptions of MOAs of mAbs that target molecules towards MG treatment.

RESULTS

New therapeutic targets include FcRn and molecules such as CD38, CD40, CD19, MS4A1, and interleukin-6 receptor. A standardized graphical representation of the MOAs of selected mAbs was created and integrated within IMGT/mAb-DB. The main mechanisms involved in these mAbs are either blocking or neutralizing. Therapies directed to B cell depletion and plasma cells have a blocking MOA with an immunosuppressant effect along with Fc-effector function (MS4A1, CD38) or FcγRIIb engager effect (CD19). Monoclonal antibodies targeting the complement also have a blocking MOA with a complement inhibitor effect, and treatments targeting T cells have a blocking MOA with an immunosuppressant effect (CD40) and Fc-effector function (IL6R). On the other hand, FcRn antagonists present a neutralizing MOA with an FcRn inhibitor effect.

CONCLUSION

The MOA of each new mAb needs to be considered in association with the immunopathogenesis of each of the subtypes of MG in order to integrate the new mAbs as a viable and safe option in the therapy decision process. In IMGT/mAb-DB, mAbs for MG are characterized by their sequence, domains, and chains, and their MOA is described.

Current drug treatment of myasthenia gravis

PURPOSE OF REVIEW

Myasthenia Gravis (MG) is a rare neurological disorder affecting the neuromuscular junction. Clinical hallmarks are fatigability and weakness affecting the extraocular, axial, limb and/or respiratory muscles. Despite immunosuppressive treatment, mainly based on corticosteroids and nonsteroidal immunosuppressants, the burden of MG is still significant, both in terms of inadequate disease control and burdensome side effects. Driven by such limits, the past years have been characterized by an escalation of MG drug development, with novel molecules which now focuses on having a more targeted effect, with a higher safety and efficacy profile.

RECENT FINDINGS

As the pathogenic mechanism of MG are slowly being unravelled, new potential targets for treatments are being considered. This has led since 2017 to the Food and Drug Administration (FDA)-approval of three new drugs that either act by blocking the complement system (i.e., eculizumab and ravulizumab) or by blocking the neonatal Fc receptor thus preventing immunoglobulin recycling and reducing imunoglobulin G (IgG) antibodies (i.e., efgartigimod). Other drugs, with similar mechanism of action, are currently under review for approval.

SUMMARY

The repertoire of available and developmental therapies for MG is rapidly expanding, finally responding to the unmet need of a more targeted and effective therapeutic approach in MG.

Fc-Engineered Therapeutic Antibodies: Recent Advances and Future Directions

Monoclonal therapeutic antibodies have revolutionized the treatment of cancer and other diseases. Fc engineering aims to enhance the effector functions or half-life of therapeutic antibodies by modifying their Fc regions. Recent advances in the Fc engineering of modern therapeutic antibodies can be considered the next generation of antibody therapy. Various strategies are employed, including altering glycosylation patterns via glycoengineering and introducing mutations to the Fc region, thereby enhancing Fc receptor or complement interactions. Further, Fc engineering strategies enable the generation of bispecific IgG-based heterodimeric antibodies. As Fc engineering techniques continue to evolve, an expanding portfolio of Fc-engineered antibodies is advancing through clinical development, with several already approved for medical use. Despite the plethora of Fc-based mutations that have been analyzed in in vitro and in vivo models, we focus here in this review on the relevant Fc engineering strategies of approved therapeutic antibodies to finetune effector functions, to modify half-life and to stabilize asymmetric bispecific IgGs.

Therapeutic Antibodies in Medicine

Antibody engineering has developed into a wide-reaching field, impacting a multitude of industries, most notably healthcare and diagnostics. The seminal work on developing the first monoclonal antibody four decades ago has witnessed exponential growth in the last 10-15 years, where regulators have approved monoclonal antibodies as therapeutics and for several diagnostic applications, including the remarkable attention it garnered during the pandemic. In recent years, antibodies have become the fastest-growing class of biological drugs approved for the treatment of a wide range of diseases, from cancer to autoimmune conditions. This review discusses the field of therapeutic antibodies as it stands today. It summarizes and outlines the clinical relevance and application of therapeutic antibodies in treating a landscape of diseases in different disciplines of medicine. It discusses the nomenclature, various approaches to antibody therapies, and the evolution of antibody therapeutics. It also discusses the risk profile and adverse immune reactions associated with the antibodies and sheds light on future applications and perspectives in antibody drug discovery.

Rozanolixizumab: First Approval

Rozanolixizumab (rozanolixizumab-noli; RYSTIGGO®) is a high affinity humanized immunoglobulin G4 monoclonal antibody directed against human neonatal Fc receptor (FcRn). Administered subcutaneously, it is being developed by UCB Pharma for the treatment of autoimmune diseases and received its first approval on 27 June 2023 in the USA for the treatment of generalized myasthenia gravis (gMG) in adults who are anti-acetylcholine receptor (AChR) or anti-muscle-specific kinase (MuSK) antibody positive. Rozanolixizumab is the first agent to be approved in the USA for both anti-AChR and anti-MuSK antibody-positive gMG. A regulatory assessment of rozanolixizumab for the treatment of gMG is currently underway in the EU and Japan. Clinical development is ongoing for the treatment of leucine-rich glioma-inactivated 1 autoimmune encephalitis, myelin oligodendrocyte glycoprotein (MOG) antibody disease and severe fibromyalgia syndrome. This article summarizes the milestones in the development of rozanolixizumab leading to this first approval for the treatment of gMG in adults who are anti-AChR or anti-MuSK antibody positive.

FcRN receptor antagonists in the management of myasthenia gravis

Myasthenia gravis (MG) is an autoimmune disorder characterized by autoantibodies specifically directed against proteins located within the postsynaptic membrane of the neuromuscular junction. These pathogenic autoantibodies can be reduced by therapies such as plasma exchange, IVIG infusions and other immunosuppressive agents. However, there are significant side effects associated with most of these therapies. Since there is a better understanding of the molecular structure and the biological properties of the neonatal Fc receptors (FcRn), it possesses an attractive profile in treating myasthenia gravis. FcRn receptors prevent the catabolism of IgG by impeding their lysosomal degradation and facilitating their extracellular release at physiological pH, consequently extending the IgG half-life. Thus, the catabolism of IgG can be enhanced by blocking the FcRn, leading to outcomes similar to those achieved through plasma exchange with no significant safety concerns. The available studies suggest that FcRn holds promise as a versatile therapeutic intervention, capable of delivering beneficial outcomes in patients with distinct characteristics and varying degrees of MG severity. Efgartigimod is already approved for the treatment of generalized MG, rozanolixizumab is under review by health authorities, and phase 3 trials of nipocalimab and batoclimab are underway. Here, we will review the available data on FcRn therapeutic agents in the management of MG.