Current Treatment of Myasthenia Gravis

Efgartigimod as a novel FcRn inhibitor for autoimmune disease

Immunoglobulin G (IgG) autoantibodies can lead to the formation of autoimmune diseases through Fab and/or Fc-mediated interactions with host molecules as well as activated T cells. The neonatal Fc receptor (FcRn) binds at acidic pH IgG and albumin, and the mechanism for prolonging serum IgG half-life is making IgG re-entry into circulation by prompting it not to be degraded by lysosomes and back to the cell surface. Given the FcRn receptor's essential role in IgG homeostasis, one of the strategies to promote the quick degradation of endogenous IgG is to suppress the function of FcRn, which is beneficial to the treatment of IgG-driven autoimmune disorders like myasthenia gravis (MG), chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), stiff person syndrome, and immune thrombocytopenia (ITP). We elaborately read the literature about efgartigimod and systematically reviewed the research progress and clinical application of this novel FcRn inhibitor in autoimmune diseases. Efgartigimod is the firstly FcRn antagonist developed and was approved on 17 December 2021 by the United States for the therapy of acetylcholine receptor-positive MG. In January 2022, efgartigimod received its second regulatory approval in Japan. In addition, the market authorization application in Europe was submitted and validated in August 2021. China's National Medical Products Administration officially accepted the marketing application of efgartigimod on July 13, 2022. To suppress the function of FcRn, which is beneficial to the treatment of IgG-driven autoimmune disorders like MG, CIDP, ITP, and stiff person syndrome. We review the rationale, clinical evidence, and future perspectives of efgartigimod for the treatment of autoimmune disease.

Efgartigimod as a fast-acting add-on therapy in manifest and impending myasthenic crisis: A single-center case series

Efgartigimod was the first-in-class neonatal Fc receptor antagonist approved for the treatment of acetylcholine receptor antibody positive (AChR+), Myasthenia Gravis Foundation of America (MGFA) Class II-IV generalized myasthenia gravis (gMG) patients. As a novel therapy, the clinical experiences are still lacking, especially for the use of efgartigimod in manifest and impending myasthenic crisis (IMC). We reported three AChR+, gMG patients, two with myasthenic crisis (MC) and one with IMC, treated with efgartigimod. MGFA class, MG-Activity of Daily Living score (MG-ADL), Quantitative MG score (QMG), and Muscle Research Council sum score (MRC), concentration of anti-AChR antibody, IgG, globulin, and albumin, subsets of T and B lymphocyte were evaluated or measured before, during and after efgartigimod treatment. All patients showed fast and robust response to efgartigimod with marked improvement in MGFA, MG-ADL, QMG, and MRC scores. Patient 1 did not respond effectively to IVIg but was successfully rescued by add-on efgartigimod. She extubated at 7 days after the first infusion and got rid of NIV after 14-days treatment. Patient 2 and patient 3 directly used efgartigimod when symptoms were not ameliorated by adjusting of oral drugs. Patient 2 wean from BiPAP at seven days after the first infusion. Patient 3 in IMC status, overcame the severe dysphagia at three days after the first infusion. Clinical symptoms continued to improve 1-2 weeks after discharge. Concentration of anti-AChR antibody, IgG and globulin were remarkably reduced by efgartigimod treatment. Our study supported that efgartigimod could act as a fast-acting rescue therapy for patients with MC or IMC. Larger studies from multicenter are required to provide further evidence.

Immune mediated myasthenia gravis in children, current concepts and new treatments: A narrative review article

Myasthenia gravis (MG) is the most frequent transmission disease in the neuromuscular junction. Juvenile myasthenia gravis (JMG) is an autoimmune antibody-mediated disease of postsynaptic endplate defined as MG presentation in patients before the age of 18 years old. While many clinical features of JMG are identical to the adults, there are some significant differences between them regarding presentation, clinical course, antibody level, and thymus histopathology. In JMG, ocular symptoms are more frequent, the clinical course is comparably benign, and the outcome is better than adult MG. Antibodies attack the muscle endplate proteins in the postsynaptic membrane and interfere with transmission. These antibodies in most patients are against the acetylcholine receptors, but they may also be directed toward muscle-specific kinase, lipoprotein-related protein 4, and agrin. Findings show racial influences and genetic effects on the occurrence of JMG. The essential clinical symptom is fatigable weakness of muscles that can be in the form of isolated ocular type or more disseminated weakness. The diagnosis of JMG is essentially clinical, with fluctuating patterns of weakness and easy fatigability, but a series of diagnostic evaluations can confirm the diagnosis. Precise diagnostic evaluation and distinction from congenital myasthenic syndromes is critical. The treatment plan is conducted according to the clinical course (ocular or generalized), antibody type, and disease severity. The mainstay of treatment includes symptomatic therapy, long-lasting immunosuppressive treatment and treatment of myasthenic crisis. Novel medications are introduced and conducted to the specific pathophysiologic mechanisms of the disease, and they are used primarily in the refractory MG.

Cost-effectiveness of eculizumab and efgartigimod for the treatment of anti-acetylcholine receptor antibody-positive generalized myasthenia gravis

BACKGROUND

Eculizumab and efgartigimod were approved to treat anti-acetylcholine receptor antibody-positive generalized myasthenia gravis (anti-AChR Ab-positive gMG). These relatively new biological treatments provide a more rapid onset of action and improved efficacy compared with conventional immunosuppressive treatments, but at a higher cost.

OBJECTIVE

To assess the cost-effectiveness of eculizumab and, separately, efgartigimod, each added to conventional therapy vs conventional therapy alone, among patients with refractory anti-AChR Ab-positive gMG and those with anti-AChR Ab-positive gMG, respectively.

METHODS

A Markov model with 4 health states was developed, evaluating costs and utility with a 4-week cycle length and lifetime time horizon from a health care system perspective and a modified societal perspective including productivity losses from patients and caregiver burden. Model inputs were informed by key clinical trials and relevant publications identified from targeted literature reviews, and drug costs were identified from Micromedex Red Book. Costs and outcomes were discounted at 3% per year. Incremental cost-effectiveness ratios (ICERs; cost per quality-adjusted life-year [QALY] gained) were calculated for each comparison.

RESULTS

Among the corresponding populations, lifetime costs and QALYs, respectively, for eculizumab were $5,515,000 and 11.85, and for conventional therapy, $308,000 and 10.29, resulting in an ICER of $3,338,000/QALY gained. For efgartigimod, lifetime costs and QALYs, respectively, were $6,773,000 and 13.22, and for conventional therapy, $322,000 and 9.98, yielding an ICER of $1,987,000/QALY gained. After applying indirect costs in a modified societal perspective, the ICERs were reduced to $3,310,000/QALY gained for eculizumab and $1,959,000/QALY gained for efgartigimod.

CONCLUSIONS

Eculizumab and efgartigimod are rapidly acting and effective treatments for myasthenia gravis. However, at their current price, both therapies greatly exceeded common cost-effectiveness thresholds, likely limiting patient access to these therapies.

Real-World Case Series of Efgartigimod for Japanese Generalized Myasthenia Gravis: Well-Tailored Treatment Cycle Intervals Contribute to Sustained Symptom Control

INTRODUCTION

Myasthenia gravis (MG), an immune disorder affecting nerve-muscle transmission, often necessitates tailored therapies to alleviate longitudinal symptom fluctuations. Here, we aimed to examine and compare the treatment cycle intervals and efficacy of efgartigimod in four patients. This case series mainly offers insights into personalized treatment cycle intervals and the efficacy of efgartigimod for patients with MG in our facility in Japan.

METHODS

We retrospectively analyzed four patients with MG (2 patients with early-onset, 1 with late-onset, and 1 with seronegative MG, mainly managed with oral immunosuppressants as prior treatments) who completed four or more cycles of efgartigimod treatment from January 2022 to September 2023. We focused on changes in serum immunoglobulin (IgG) level, acetylcholine receptor antibody (AChR-Ab) titer, and quantitative MG (QMG) score.

RESULTS

Efgartigimod, administered at a median of 5.0 [IQR 5.0, 7.5] weeks between cycles, led to decreased serum IgG levels in all patients and reduced AChR-Ab titers in seropositive patients. All patients showed sustained MG symptom improvement, with considerably reduced QMG scores before efgartigimod treatment. None of the patients required rescue medications or developed treatment-related adverse events.

CONCLUSIONS

Customized efgartigimod administration intervals effectively enhanced clinical outcomes in patients with MG without notable symptom fluctuations, demonstrating the benefits of individualized treatment approaches and validating the safety of efgartigimod during the study period.

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.

Long-Term Healthcare Resource Utilization and Costs among Patients with Myasthenia Gravis: A Swedish Nationwide Population-Based Study

INTRODUCTION

Healthcare costs and societal impact of myasthenia gravis (MG), a potentially life-threatening rare, chronic neuromuscular disease, are sparsely studied. We assessed healthcare resource utilization (HCRU) and associated costs among patients with newly diagnosed (ND) and preexisting (PE) MG in Sweden.

METHODS

This observational, retrospective cohort study used data from four linkable Swedish nationwide population-based registries. Adult MG patients receiving pharmacological treatment for MG and having ≥24-month follow-up during the period January 1, 2010, to December 31, 2017, were included.

RESULTS

A total of 1,275 patients were included in the analysis, of which 554 patients were categorized into the ND MG group and 721 into the PE MG group. Mean (±SD) age was 61.3 (±17.4) years, and 52.3% were female. In the first year post-diagnosis, ND patients had significantly higher utilization of acetylcholinesterase inhibitors (96.0% vs. 83.9%), corticosteroids (59.6% vs. 45.8%), thymectomy (12.1% vs. 0.7%), and plasma exchange (3.8% vs. 0.6%); had higher all-cause (70.9% vs. 35.8%) and MG-related (62.5% vs. 18.4%) hospitalization rates with 11 more hospitalization days (all p < 0.01) and an increased risk of hospitalization (odds ratio [95% CI] = 4.4 [3.43, 5.64]) than PE MG. In year 1 post-diagnosis, ND MG patients incurred EUR 7,302 (p < 0.01) higher total all-cause costs than PE MG, of which 84% were estimated to be MG-related and the majority (86%) were related to inpatient care. These results remained significant also after controlling for baseline demographics and comorbidities (p < 0.01). In year 2 post-diagnosis, the all-cause medical costs decreased by ∼55% for ND MG from year 1 and were comparable with PE MG.

CONCLUSION

In this population-based study, MG patients required significantly more healthcare resources in year 1 post-diagnosis than PE MG primarily due to more pharmacological treatments, thymectomies, and associated hospitalizations. These findings highlight the need to better understand potential factors including disease characteristics associated with increased health resource use and costs and need for more efficacious treatments early in the disease course.

Perspectives of people with myasthenia gravis on physical activity and experience of physical activity advice from health professionals in the Australian context: a qualitative study

PURPOSE

Physical activity is an important modifiable determinant of health. There has been a historical aversion to movement in people with myasthenia gravis (MG) due to the pathophysiology of the disease, however, research suggests engagement in physical activity is safe and does not exacerbate symptoms. There are currently no studies investigating the qualitative perspectives of people with MG on physical activity. The aim of this study was to explore perceptions of physical activity, barriers, enablers, and participants' experiences of physical activity advice from health professionals.

MATERIALS AND METHODS

Semi-structured interviews were used, with verbatim transcripts analysed using content analysis.

RESULTS

Ten adults (median age 64.5 years) living in Australia with generalised MG were interviewed. Key findings were identified: (1) Physical activity is perceived to be important for general health and for MG; (2) Medical management and social support are key enablers; (3) Fatigue and pain are potential barriers; and (4) Experiences with healthcare professionals were considered insufficient and failed to provide disease specific advice regarding MG and physical activity.

CONCLUSION

People with MG have unique barriers and enablers to physical activity engagement that clinicians should consider when providing physical activity behaviour change support to this population.

The Efficacy and Safety of Different Targeted Drugs for the Treatment of Generalized Myasthenia Gravis: A Systematic Review and Bayesian Network Meta-analysis

BACKGROUND

The treatment of generalized myasthenia gravis (gMG) has been transformed by the development and approval of new targeted therapies. This analysis aimed to rank and compare the new therapies for gMG using efficacy and safety data from randomized controlled trials (RCTs).

METHODS

We searched PubMed, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL), and ClinicalTrials.gov (up to November 2022) for RCTs of targeted drugs for gMG. We used a Bayesian random-effects network meta-analysis (NMA) model and a Markov chain Monte Carlo (MCMC) model for statistical analysis. The primary outcome was the change in quantitative myasthenia gravis score (QMGS) from baseline, while the secondary outcome was the risk ratio (RR) of adverse events (AEs) during treatment. The surface under the cumulative ranking curve (SUCRA) was used to rank these targeted drugs, with higher SUCRA values indicating better efficacy or lower likelihood of AEs.

RESULTS

In total, 13 studies (872 subjects) were included in this analysis evaluating 10 targeted drugs (batoclimab, belimumab, CFZ533, eculizumab, efgartigimod, nipocalimab, rituximab, ravulizumab, rozanolixizumab, and zilucoplan). With regards to the primary outcome, batoclimab [standardized mean difference (SMD), - 1.61; 95% credible interval (CrI), - 2.78, - 0.43] significantly reduced QMGS in patients with gMG when compared with placebo and was ranked as the most efficacious drug. Ranked second and third were eculizumab (SMD, - 0.67; 95% CrI, 1.43, 0.01) and zilucoplan (SMD, - 0.54; 95% CrI, - 1.56, 0.46), respectively. Nipoclimab (SMD, - 0.02; 95% CrI, - 1.04, 1.00) had the worst efficacy and ranked last among all targeted drugs. In our study, except for batoclimab, there was no statistically significant difference in the reduction of patient QMGS for the remaining targeted agents compared with placebo. With regards to the secondary outcomes, only batoclimab (RR, 0.19; 95% CrI, 0, 0.97) led to a significant reduction in the incidence of AEs when compared with the placebo. Belimumab (RR, 0.85; 95% CrI, 0.57, 1.19), CFZ533 (RR, 0.95; 95% CrI, 0.72, 1.25), eculizumab (RR, 0.99; 95% CrI, 0.85, 1.21), and efgartigimod (RR, 0.93; 95% CrI, 0.76, 1.15) also led to a lower incidence of AEs, although these effects were not significantly different from the placebo.

CONCLUSIONS

Batoclimab had the best efficacy and safety for the treatment of gMG and was ranked first out of the 10 targeted drugs included in this study. Eculizumab was ranked second, and nipocalimab had the worst efficacy. With the exception of batoclimab, the incidence of AEs for the remaining drugs was not statistically significantly different from placebo. We note, however, that wide CrIs reflect the uncertainty in this analysis owing to the small number of available studies and low numbers of study participants; moreover, batoclimab had the widest CrI of all drugs in this analysis. More well-designed studies with long-term follow-up are needed to further evaluate and compare the efficacy and safety of these drugs in the future.

Dexamethasone improves thymoma-associated myasthenia gravis via the AKT-mTOR pathway

Clinically, thymoma patients are often complicated with myasthenia gravis (MG). Dexamethasone, a glucocorticoid with anti-inflammatory effects, could be used as an immunosuppressant for thymoma-associated MG, but the mechanism of action remains to be explored. In this study, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, weighted gene co-expression network analysis (WGCNA) of potential targets was performed by screening the intersection targets of dexamethasone and thymoma-associated MG from the database. Furthermore, the key targets and core active components were identified by topological analysis of the protein-protein interaction (PPI) network. Molecular docking technology was applied to screen the complexes with stable binding of dexamethasone and core targets. Patients with thymoma were divided into two groups according to whether they received dexamethasone before operation, and immunohistochemistry and western blot were used to verify the selected target of dexamethasone in treating thymoma-associated MG. The results showed that the action pathway of dexamethasone on the disease was closely enriched to phosphatidylinositol 3-kinase (PI3K)-protein kinase B (PKB/AKT), mammalian target of rapamycin (mTOR) signaling pathways. The expressions of AKT1 and its downstream molecule mTOR in the thymoma microenvironment of thymoma-associated MG patients who did not receive dexamethasone before operation were higher than those in the group receiving dexamethasone before operation. This study demonstrates that dexamethasone can promote apoptosis through the AKT-mTOR pathway for the treatment of thymoma-associated MG, as validated by network pharmacology predictions and clinical specimen experiments, and can be verified by large-scale clinical trials in the future. This study also provides theoretical support and new research perspectives for this disease.

[Experience of using eculizumab in refractory myasthenia gravis]

Myasthenia gravis (MG) is a chronic autoimmune disease mediated by autoreactive T- and B-cells and manifested by progressive pathological muscle weakness and fatigue. Traditional immunomodulatory treatment does not always lead to the clinical picture significant improvement, despite adequate dosage and duration of use. Refractory myasthenia gravis requires new therapeutic approaches development and implementation. The range of target innovative agents in refractory MG includes monoclonal antibodies, which act directly on individual components of the complement system. Based on the results of randomized controlled trials, data on the effectiveness and safety of eculizumab, which inhibits the C5 component of the complement system, is presented. We present our own clinical experience of using eculizumab in a young woman with refractory generalized AChR-positive MG with a rapid decrease in the severity of symptoms to a minimum level and restoration of ability to work, and the absence of adverse events during therapy.

Depression: A Contributing Factor to the Clinical Course in Myasthenia Gravis Patients

Background and Objectives: The association between myasthenia gravis (MG) and depression is intricate and characterized by bidirectional causality. In this regard, MG can be a contributing factor to depression and, conversely, depression may worsen the symptoms of MG. This study aimed to identify any differences in the progression of the disease among patients with MG who were also diagnosed with depression as compared to those without depression. Our hypothesis focused on the theory that patients with more severe MG symptoms may have a higher likelihood of suffering depression at the same time. Materials and Methods: One hundred twenty-two male and female patients (N = 122) aged over 18 with a confirmed diagnosis of autoimmune MG who were admitted to the Neurology II department of Myasthenia Gravis, Clinical Institute Fundeni in Bucharest between January 2019 and December 2020, were included in the study. Patients were assessed at baseline and after six months. The psychiatric assessment of the patients included the Hamilton Depression Rating Scale-17 items (HAM-D), and neurological status was determined with two outcome measures: Quantitative Myasthenia Gravis (QMG) and Myasthenia Gravis Activities of Daily Life (MG-ADL). The patients were divided into two distinct groups as follows: group MG w/dep, which comprised 49 MG patients diagnosed with depressive disorder who were also currently receiving antidepressant medication, and group MG w/o dep, which consisted of 73 patients who did not have depression. Results: In our study, 40.16% of the myasthenia gravis (MG) patients exhibited a comorbid diagnosis of depression. Among the MG patients receiving antidepressant treatment, baseline assessments revealed a mean MG-ADL score of 7.73 (SD = 5.05), an average QMG score of 18.40 (SD = 8.61), and a mean Ham-D score of 21.53 (SD = 7.49). After a six-month period, a statistically significant decrease was observed in the MG-ADL (2.92, SD = 1.82), QMG (7.15, SD = 4.46), and Ham-D scores (11.16, SD = 7.49) (p < 0.0001). These results suggest a significant correlation between MG severity and elevated HAM-D depression scores. Regarding the MG treatment in the group with depression, at baseline, the mean dose of oral corticosteroids was 45.10 mg (SD = 16.60). Regarding the treatment with pyridostigmine, patients with depression and undergoing antidepressant treatment remained with an increased need for pyridostigmine, 144.49 mg (SD = 51.84), compared to those in the group without depression, 107.67 mg (SD = 55.64, p < 0.001). Conclusions: Our investigation confirms that the occurrence of depressive symptoms is significantly widespread among individuals diagnosed with MG. Disease severity, along with younger age and higher doses of cortisone, is a significant factor associated with depression in patients with MG. Substantial reductions in MG-ADL and QMG scores were observed within each group after six months, highlighting the effectiveness of MG management. The findings suggest that addressing depressive symptoms in MG patients, in addition to standard MG management, can lead to improved clinical outcomes.

Exacerbation of Thymoma-Associated Myasthenia Gravis Following Efgartigimod Treatment Related to Anti-acetylcholine Receptor Antibody Overshoot: A Report of Two Cases

Myasthenia gravis (MG), a chronic, autoimmune disease affecting the neuromuscular junction, arises from various autoantibodies, including those against the acetylcholine receptor (AChR). Recently, efgartigimod, a human IgG1 antibody Fc fragment engineered to reduce the pathogenic IgG autoantibody level, was developed as a treatment for MG. However, the long-term effects of the treatment are still unclear. The present report describes two novel cases of thymoma-associated MG exacerbation following efgartigimod treatment related to anti-AChR antibody overshoot. Both cases shared certain characteristics, including anti-AChR antibody positivity and post-thymectomy status. After a few cycles of efgartigimod treatment, their MG deteriorated, and their anti-AChR antibody titer exceeded the level before efgartigimod therapy. Prior studies show that anti-AChR antibody titer does not correlate with the disease severity of MG. However, previous studies have reported antibody overshoot following plasma exchange, which, like efgartigimod, reduces the level of plasma IgG and autoantibodies. Thus, MG exacerbation with anti-AChR antibody overshoot may be an adverse effect of both efgartigimod and plasma exchange. When clinical symptoms in patients with thymoma-associated MG receiving efgartigimod deteriorate despite low IgG, assessing the anti-AChR antibody level can be important for reconsidering the treatment strategy.

Clinical features, treatments, their impact, and quality of life for Myasthenia Gravis patients in Australia

This survey provides an update on the experience of Myasthenia Gravis (MG) patients in Australia. Items were drawn from the 2011 Australian Survey and a 2019 US survey allowing for comparative discussion of survey findings. Patients were recruited through the Myasthenia Alliance Australia. Following consent, patients completed an online survey using REDCap software. Questions included demographics, clinical features, treatment side-effects and quality of life (QOL) scales. Samples for completion of survey sections ranged from N = 242-280 representing a power level of over 80%. Female and seronegative patients reported a significantly greater symptom load, earlier disease onset, longer time to diagnosis, more MG exacerbations, treatment side-effects, and poorer QOL. For exacerbation management there was a higher rate of oral corticosteroid use (66%), a lower use of Intravenous Immunoglobulin (IVIg, 47%) and particularly, Therapeutic Plasma Exchange (TPE, 4.5%) within this sample. Although steroid induced side-effects were rarer (9-34%), a comparatively high use of corticosteroids was reported for current and overall treatments including those for MG crises (52-83%). Common treatment side-effects reported by 57-85% of patients, included fatigue, weight gain, a decrease in the ability to fight infections, gastrointestinal symptoms, and muscle weakness. The impact of MG on daily activities and QOL was considerable, but those who had a thymectomy reported better QOL. The survey identified areas for potential practice improvement in MG treatments (corticosteroids, IVIg, TPE), particularly for exacerbation management, and review is recommended. Further research on gender and antibody status differentials regarding clinical features is required.

Myasthenia gravis: Molecular mechanisms and promising therapeutic strategies

Myasthenia gravis (MG) is a type of autoimmune disease caused by the blockage of neuromuscular junction transmission owing to the attack of autoantibodies on transmission-related proteins. Related antibodies, such as anti-AChR, anti-MuSK and anti-LRP4 antibodies, can be detected in most patients with MG. Although traditional therapies can control most symptoms, several challenges remain to be addressed, necessitating the development of more effective and safe treatment strategies for MG. With the in-depth exploration on the mechanism and immune targets of MG, effective therapies, especially therapies using biologicals, have been reported recently. Given the important roles of immune cells, cytokines and intercellular interactions in the pathological process of MG, B-cell targeted therapy, T-cell targeted therapy, proteasome inhibitors targeting plasma cell, complement inhibitors, FcRn inhibitors have been developed for the treatment of MG. Although these novel therapies exert good therapeutic effects, they may weaken the immunity and increase the risk of infection in MG patients. This review elaborates on the pathogenesis of MG and discusses the advantages and disadvantages of the strategies of traditional treatment and biologicals. In addition, this review emphasises that combined therapy may have better therapeutic effects and reducing the risk of side effects of treatments, which has great prospects for the treatment of MG. With the deepening of research on immunotherapy targets in MG, novel opportunities and challenges in the treatment of MG will be introduced.

Drug and pro-drug substrates and pseudo-substrates of human butyrylcholinesterase

Butyrylcholinesterase (BChE) is present in plasma and numerous cells and organs. Its physiological function(s) is(are) still unclear. However, this enzyme is of pharmacological and toxicological importance. It displays a broad specificity and is capable of hydrolyzing a wide range of substrates with turnovers differing by several orders of magnitude. Nowaday, these substrates include more than two dozen carboxyl-ester drugs, numerous acetylated prodrugs, and transition state analogues of acetylcholine. In addition, BChE displays a promiscuous hydrolytic activity toward amide bonds of arylacylamides, and slowly hydrolyzes carbamyl- and phosphoryl-esters. Certain pseudo-substrates like carbamates and organophosphates are major drugs of potential medical interest. The existence of a large genetic poly-allelism, affecting the catalytic properties of BChE is at the origin of clinical complications in the use of certain drugs catabolized by BChE. The number of drugs and prodrugs hydrolyzed by BChE is expected to increase in the future. However, very few quantitative data (Km, kcat) are available for most marketed drugs, and except for myorelaxants like succinylcholine and mivacurium, the impact of BChE genetic mutations on catalytic parameters has not been evaluated for most of these drugs.

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.

Targeting neuromuscular junction to treat neuromuscular disorders

The integrity and preservation of the neuromuscular junction (NMJ), the interface between the motor neuron and skeletal muscle, is critical for maintaining a healthy skeletal muscle. The structural and/or functional defects in the three cellular components of NMJ, namely the pre-synaptic terminal, synaptic cleft, and post-synaptic region, negatively affect skeletal muscle mass and/or strength. Therefore, NMJ repair appears to be an appropriate therapy for muscle disorders. Mouse models provide a detailed molecular characterization of various cellular components of NMJ with relevance to human diseases. This review discusses different molecular targets on the three cellular components of NMJ for treating muscle diseases. The potential effects of these therapies on NMJ morphology and motor performance, their therapeutic efficacy, and clinical relevance are discussed. Collectively, the available data supports targeting NMJ alone or as an adjunct therapy in treating muscle disorders. However, the potential impact of such interventions on human patients with muscle disorders requires further investigation.

Myasthenia gravis as initial presentation of a pancreatic neuroendocrine tumor: A case report

Myasthenia gravis (MG) is a heterogeneous autoimmune disease, which is characterized by a postsynaptic neuromuscular transmission defect, with antibodies directly targeting the acetylcholine receptor (AChR) or other structural proteins of the neuromuscular junction. The majority of MG cases are associated with thymic pathologies, including thymoma, thyroiditis, autoimmune diseases or malignant hematologic neoplasia. The present study reported a rare case of AChR-positive and late-onset ocular MG, which rapidly progressed to a generalized myasthenic syndrome as an initial presentation of a pancreatic neuroendocrine neoplasia (pNEN). Following complete surgical resection of the pNEN, the myasthenic syndrome was improved and the anti-AChR antibody titers were reduced. It has been reported that MG is a paraneoplastic syndrome in thymic neoplasms and less common in hematologic malignancies. However, currently, only few cases of MG as initial presentation of a solid tumor, and more particular of a neuroendocrine neoplasm, have been reported in the literature. In conclusion, surveillance for extrathymic solid malignancies in newly diagnosed patients with MG could promote the early diagnosis of associated tumor diseases.

The economic burden of individuals living with generalized myasthenia gravis and facing social determinants of health challenges

Objective

Better understanding the impact of social determinants of health (SDOH) barriers from the patient perspective is crucial to improve holistic patient support in generalized myasthenia gravis (gMG), a rare autoimmune disorder with high disease and treatment burden. The objective of this study was to identify economic challenges experienced by individuals living with gMG and SDOH barriers to better address current unmet needs.

Methods

Adults (18-75 years) living with gMG and experiencing SDOH barriers in the United States were recruited to a mixed-methods study including qualitative interviews and a web-based quantitative survey. Quotas were implemented to include a balanced spread of baseline demographic categories including insurance type, living environment, and employment status among the study sample. Direct and indirect economic challenges were identified by degree of concern.

Results

The survey was completed by 38 individuals living with gMG, the majority of whom were enrolled in public insurance and not employed. The most commonly reported major economic concerns were managing funds for emergency care (66%), loss of income (61%), and non-medical expenses (58%), highlighting the diversity of economic challenges. Individuals who were using public insurance plans, living in non-urban environments, and unemployed experienced pronounced challenges around managing non-medical costs and accessing government assistance.

Conclusion

Both direct and indirect costs were emphasized as major concerns among individuals living with gMG and SDOH barriers. Increasing access to relevant, personalized, and holistic resources, including care management, should be prioritized to improve disease management and outcomes for individuals living with gMG.

Fatal Disseminated Strongyloidiasis in an Immunosuppressed Patient During COVID-19 Pandemic

INTRODUCTION

This report presents a fatal case of disseminated strongyloidiasis in a patient with myasthenia gravis and diabetes mellitus who had received corticosteroid therapy.

CASE REPORT

The patient was a 67-year-old woman living in a rural area endemic for Strongyloides stercoralis in northern Iran. Disseminated strongyloidiasis was diagnosed in the advanced stage of the disease, with enormous numbers of larvae demonstrated in direct smears prepared from stool samples and stomach biopsy. Despite treatment with ivermectin and antibiotics, the patient succumbed to the severity of the infection.

CONCLUSION

Clinicians working in endemic areas should be mindful of the possibility of gastric involvement in strongyloidiasis, even if symptoms are nonspecific. We recommend that high-risk individuals be screened for S. stercoralis prior to immunosuppressive therapy in endemic regions to raise awareness and prevent similar cases.

The First Case of Burkholderia cepacia-Induced Myasthenic Crisis

We report the case of a 62-year-old male patient with a previous diagnosis of myasthenia gravis who experienced a myasthenic crisis due to a lower respiratory tract infection caused by Burkholderia cepacia. The patient was admitted to the neuro-intensive care unit and received ventilatory support to address respiratory insufficiency. Treatment included tigecycline and piperacillin-tazobactam for the suspected bacterial infection, as well as targeted management for the myasthenic crisis. Following a successful recovery and favorable clinical response, this case report aims to contribute to the literature by discussing the patient's presentation and exploring the incidence and characteristics of B. cepacia-related myasthenic crisis.

Therapeutic and prognostic features in myasthenia gravis patients followed in a tertiary neuromuscular diseases center in Turkey

Introduction

In this study, we aim to evaluate the treatment responses and prognostic characteristics of Myasthenia Gravis (MG) patients followed in a tertiary neuromuscular diseases center in Turkey.

Methods

One hundred seventy four MG patients (between years 2011 and 2022) in Antalya, Turkey were diagnosed, and evaluated on a classification of MG was based on Myasthenia. Gravis Foundation of America (MGFA) clinical classification. Exclusion of other possible diseases in the differential diagnosis and support by beneficial response to treatment with acetylcholinesterase inhibitors were also taken into consideration.

Results

Mean age of participants was 54.86 (SD = 14.856; min-max = 22-84). Ninety (51.7%) were female. MG was more common in women under the age of 65 (58%) and in men over the age of 65 (64%). Generalized MG was seen in 75.3% of the patients. Anti-AChR positivities were detected in 52.3%, Anti-MuSK positivity in 4.6%, and seronegativity in 22.4%. Thymoma was detected in nearly 9.8% and thymectomy was performed in 28.7 percent. Most of the patients (57.5%) were using corticosteroids. Azathioprine was used by 39% and mycophenolate mofetil by 10.3% of patients. Mortality was higher and disease was more severe in late-onset (>50 years) MG patients (especially in the COVID-19 pandemic). Eight patients (four women, four men, mean age 75.5 years) died during follow-up. None of them died due to myasthenic worsening, two died due to malignancy and two due to infection. During the COVID pandemic, 16 patients (9.2%) had COVID infection. Four patients died due to COVID-19 infection, these four patients had serious comorbidities, and three of them were elderly (>75 years).

Conclusion

In conclusion, MG is more common in women between the ages of 20-40 and in men over the age of 65. The use of corticosteroids was more common under the age of 50, and the use of non-steroidal immunosuppressant agents was more common over the age of 50. Thymectomy is still an important supportive treatment approach in anti-AChR positive and seronegative generalized patients under 50 years of age. IVIG and plasmapheresis are effective treatments during acute exacerbations and bridging periods of treatments. Specific treatments are needed especially for resistant group of patients.

Lymphoplasmapheresis versus plasma exchange in severe myasthenia gravis: a retrospective cohort study

Background

Lymphoplasmapheresis (LPE) is a new therapy developed on the basis of traditional plasma exchange (PE) in combination with leukapheresis. Currently, it remains unclear whether PE and LPE show differences in efficacy for severe MG.

Methods

A retrospective analysis was conducted on 198 MG patients, 75 in the PE group and 123 in the LPE group, and the patients' Myasthenia Gravis Foundation of America (MGFA) Clinical Classification was Class IV. The treatment outcome was the change in Quantitative Myasthenia Gravis Score (QMGS) from baseline to the end of treatment. Propensity score matching (PSM) was applied for the balance of confounders between the two groups.

Results

In this study cohort, the safety profile of LPE and PE was good and no serious adverse events were observed. Based on PSM, 62 patients treated with LPE and 62 patients treated with PE were entered into a comparative efficacy analysis. In the PE group, patients underwent a total of 232 replacements, with a mean of 3.74. PE significantly improved the patients' QMGS performance, with the mean QMGS decreasing from 22.98 ± 4.03 points at baseline to 18.34 ± 5.03 points after treatment, a decrease of 4.68 ± 4.04 points (p < 0.001). A decrease of ≥3 points in QMGS was considered a significant improvement, with a treatment response rate of 67.7% in the PE group. In the LPE group, patients received a total of 117 replacements, with a mean of 1.89. The patients' mean QMGS was 23.19 ± 4.11 points at baseline and was 16.94 ± 5.78 points after treatment, a decrease of 6.26 ± 4.39 points (p < 0.001). The improvement in QMGS was more significant in patients treated with LPE compared to the PE group (p = 0.039). The treatment response rate in the LPE group was 79%, which was not significantly different compared to the PE group (p = 0.16). The LEP group had a shorter mean length of stay compared to the PE group (10.86 ± 3.96 vs. 12.14 ± 4.14 days), but the difference was not statistically significant (p = 0.13). During the 2-month follow-up period, LPE may be associated with better functional outcomes for patients, with lower QMG score and relapse rate. LPE and PE were both effective in reducing the levels of inflammatory cytokines (TNF-α, IL-1β, and IL-6) and AChR-Ab. Compared to PE, LPE was superior in the reduction of AChR-Ab titer.

Conclusion

In severe MG, LPE may be a more preferred treatment option than PE. It achieves treatment outcomes that are not inferior to or even better than PE with fewer replacements. This study provides further evidence to support the application of LPE as a new treatment option for MG.

Self-Reported Medication Adherence Measured with Morisky Scales in Rare Disease Patients: A Systematic Review and Meta-Analysis

BACKGROUND

The visibility of Rare Diseases is a new challenge for society. These diseases are numerous, heterogeneous in nature and distribution, characterized by a high mortality rate but low prevalence, and usually presenting a severe evolution. Adherence to medication studies in rare diseases are uncommon, due to treatment scarcity.

OBJECTIVES

The main purpose of this study is to do a meta-analysis, evaluating the level of adherence to medication in the most prevalent rare diseases.

METHODS

This work is a systematic review, and meta-analysis was registered in the International Prospective Register of Systematic Reviews (PROSPERO) (Registration number: CRD42022372843) and conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Adherence to treatment in this systematic review and meta-analysis was collected from all studies included, based on the crude numerators and denominators reported, using either the Morisky Medication Adherence Scale 4 or -8.

RESULTS

A total of 54 records were identified through database searches, or after screening relevant manuscripts' references. Finally, 18 studies were included in this systematic review and meta-analysis. A total of 1559 participants (54.18% women) aged less than 84 years old were included. Twelve studies used the MMAS-8. In 8 of them, they established the level of adherence to treatment in three categories (low, medium, and high), with the mean prevalence in each of them being 41.4%, 30.4%, and 28.2%, respectively.

CONCLUSIONS

The results observed in adherence to treatment in patients with rare diseases show great variability, due to the different aspects involved in the greater or lesser applicability of the medication.

Myasthenia gravis. Update on diagnosis and therapy

Myasthenia gravis is an autoimmune disease caused by the presence of specific antibodies targeting different postsynaptic components of the neuromuscular junction, and is clinically characterized by the presence of fatigueable muscle weakness. In the etiopathogenesis plays a central role the thymus and the most frequently detected pathogenic autoantibodies are targeted to the acetylcholine receptor. The increase in the knowledge of the immunological components of the neuromuscular junction in the last two decades has been fundamental to identify new pathogenic antibodies, reduce the percentage of patients with seronegative myasthenia, and propose a classification of patients into subgroups with clinical-therapeutic interest. In addition, in recent years, new drugs have been developed for the treatment of patients with myasthenia gravis that are refractory to conventional immunosuppressive treatment.

Efgartigimod Alfa in Generalised Myasthenia Gravis: A Profile of Its Use

Intravenous efgartigimod alfa (also known as efgartigimod alfa-fcab in the USA; Vyvgart^®) is the first neonatal Fc receptor antagonist approved in several countries worldwide, including the USA and EU for the treatment of generalised myasthenia gravis (gMG) in adults who are anti-acetylcholine receptor (AChR) antibody positive, and in Japan for the treatment of gMG regardless of antibody status. In the double-blind, placebo-controlled phase 3 ADAPT trial in patients with gMG, efgartigimod alfa significantly and rapidly reduced disease burden and improved muscle strength and quality of life compared with placebo. The clinical benefits of efgartigimod alfa were durable and reproducible. Furthermore, in an interim analysis of the ongoing open-label phase 3 ADAPT+ extension trial, efgartigimod alfa provided consistent clinically meaningful improvements in patients with gMG. Efgartigimod alfa was generally well tolerated, with most adverse events being mild to moderate in severity.

Electrophysiologic evaluation of myasthenia gravis and its mimics: real-world experience with single-fiber electromyography

OBJECTIVES

In centers which routinely perform single fiber electromyography (SFEMG) for suspected myasthenia gravis (MG), the additional benefit of other neurophysiologic investigations and the frequency of myasthenia mimics has not been ascertained. We aimed to illustrate the range of neurological and non-neurological myasthenia mimics referred for evaluation, and contrast features of their electrophysiologic evaluation with confirmed MG.

METHODS

We reviewed all SFEMG studies performed at our center between 1 January 2018 and 31 December 2020. Patient demographics, clinical phenotype, antibody status and final diagnosis were recorded. Electrophysiologic findings were correlated with clinical features and sensitivity analyses performed.

RESULTS

A total of 528 SFEMG studies were performed, of which 213 (41%) were abnormal. A diagnosis of MG was made in 101 individuals, including 46 with ocular MG and 35 with seronegative disease. Compared to myasthenia mimics with an abnormal SFEMG, individuals with MG had higher median jitter (mean consecutive difference 61 μs vs. 42 μs, p < 0.001) and a greater percentage of abnormal pairs (61% vs. 33%, p < 0.001) on SFEMG. Repetitive nerve stimulation was abnormal in 27.1% of people with MG and was associated with a generalized clinical phenotype (OR 4.17; 95% CI 1.67-10.48). Thirteen (2%) individuals with MG had normal SFEMG, of whom 10 were in clinical remission. Functional neurological disorders, cranial nerve palsies, primary ocular disease and myopathy were frequent myasthenia mimics.

CONCLUSION

SFEMG can be abnormal in a number of myasthenia mimics, and routine nerve conduction studies and electromyography should always be undertaken. In centers where SFEMG is performed routinely for the investigation of suspected MG, extensive proximal repetitive nerve stimulation can be foregone without substantially affecting diagnostic evaluation. Normal SFEMG in those with confirmed myasthenia gravis may help indicate clinical remission.

Application of lymphoplasmapheresis in the treatment of severe myasthenia gravis

Background

Lymphoplasmapheresis (LPE) is a treatment that combines traditional plasma exchange and lymphocyte removal technique. It has been applied to treat a variety of autoimmune diseases, but its application value in the treatment of severe myasthenia gravis (MG) is not yet clear. Therefore, the aim of this study was to investigate the efficacy and safety of LPE in severe MG.

Methods

Clinical data of 123 severe patients with MG (Myasthenia Gravis Foundation of America Clinical Classification, Class IV) who received LPE treatment were included in a retrospective analysis. Efficacy was evaluated by the change of Quantitative Myasthenia Gravis score (QMGS) before and after treatment. Univariate and multivariate logistic regression analysis was used to explore clinical factors affecting efficacy.

Results

A total of 220 replacements were performed in 123 patients, with an average of 1.79 replacements per patient. The overall safety of LPE was good, and no serious adverse reactions occurred. After treatment, the mean QMGS of patients decreased significantly, from 23.40 ± 4.25 points before treatment to 17.93 ± 5.61 points after treatment, a decrease of 5.47 ± 4.16 points. 75.6% of patients experienced remission of clinical symptoms. During a 2-month follow-up of 64 patients, a progressive improvement in QMGS was found. Each muscle group involved in MG responded well to LPE treatment. In addition, LPE significantly reduced the levels of AChR-Ab and inflammatory cytokines in patients. Age ≥ 50 years and co-infection were unfavorable factors affecting the efficacy.

Conclusions

In this study cohort, LPE is safe for the treatment of severe MG and achieves good treatment outcome with fewer replacements. In patients with MG, the avoidance and timely control of infection are necessary. Our study provides a potential new treatment option for severe MG.

Our Clinical Experience in the Treatment of Myasthenia Gravis Acute Exacerbations with a Novel Nanomembrane-Based Therapeutic Plasma Exchange Technology

According to the American Academy of Neurology 2011 guidelines, there is insufficient evidence to support or refute the use of therapeutic plasma exchange (TPE) for myasthenia gravis (MG). The goal of this study was to determine whether a novel nanomembrane-based TPE could be useful in the treatment of MG. Thirty-six adult patients, MGFA 4/4B and 5, with acute MG episodes were enrolled into a single-center retrospective before-and-after study to compare a conventional treatment group (n = 24) with a nanomembrane-based TPE group (n = 12). TPE or intravenous immunoglobulins (IVIG) infusions were used in impending/manifested myasthenic crises, especially in patients at high-risk for prolonged invasive ventilation (IMV) and in those tolerating non-invasive ventilation (NIV). The clinical improvement was assessed using the Myasthenia Muscle Score (0–100), with ≥20 increase for responders. The primary outcome measures included the rates of implemented TPE, IVIG, and corticosteroids immunotherapies, NIV/IMV, early tracheotomy, MMS scores, extubation time, neuro-ICU/hospital LOS, complications, and mortality rates. The univariate analysis found that IMV was lower in the nanomembrane-based group (42%) compared to the conventional treatment group (83%) (p = 0.02). The multivariate analysis using binary logistic regression revealed TPE and NIV as independent predictors for short-term (≤7 days) respiratory support (p = 0.014 for TPE; p = 0.002 for NIV). The novel TPE technology moved our clinical practice towards proactive rather than protective treatment in reducing prolonged IMV during MG acute exacerbations.

Effects of Plasma Exchange Combined with Immunoglobulin Therapy on Consciousness, Immune Function, and Prognosis in Patients with Myasthenia Gravis Crisis: A Prospective Randomized Test

Background

Myasthenia gravis (MG) is an acquired autoimmune disease. The main clinical features of MG are skeletal muscle fatigue and pathological fatigue, which worsen at night or after fatigue, such as dyspnea, dysphagia, and systemic weakness. Plasma exchange (PE) is often used in patients with acute exacerbation of MG. Intravenous immunoglobulin (IVIG) is a collection of immunoglobulins from thousands of donors. IVIG can replace a variety of immunosuppressants or PE. However, the effect of PE or IVIG on patients' consciousness, immune function, and prognosis is not clear.

Objective

A prospective randomized test of the effects of PE combined with immunoglobulin on consciousness, immune function, and prognosis in patients with myasthenia gravis crisis (MGC).

Methods

Sixty patients with MGC treated from February 2019 to April 2021 were enrolled in our hospital. The cases who received PE were set as the PE group, and those who received PE combined with immunoglobulin were set as the PE+immunoglobulin group. The efficacy, clinical score, state of consciousness, immune function, acetylcholine receptor antibody (AChR-Ab), lymphocyte (LYM), albumin (ALB) levels, and the incidence of adverse reactions were compared.

Results

The improvement rate was 100.005% in the treatment group and 83.33% in the PE group. After treatment, the clinical score of the PE+immunoglobulin group was lower than that of the PE group, and the clinical relative score of the PE+immunoglobulin group was higher than that of the PE group (P < 0.05). The number of conscious people in the PE+immunoglobulin group was more than that in the PE group (P < 0.05). Immunoglobulin A, immunoglobulin M, immunoglobulin G, and immunoglobulin G in the PE+immunoglobulin group were higher than those in the PE group (P < 0.05). The levels of AChR-Ab and ALB in the PE+immunoglobulin group were higher than those in the PE group, while the level of LYM in the PE+immunoglobulin group was lower than that in the PE group. The incidence of skin system, gastrointestinal system, nervous system, and systemic damage in the PE+immunoglobulin group was lower than that in the PE group (P < 0.05).

Conclusion

The treatment of MGC with PE combined with immunoglobulin can not only effectively enhance the consciousness and immune function of patients but also effectively promote the prognosis, and the safety of treatment can be guaranteed.