Emerging therapies for autoimmune myasthenia gravis: Towards treatment without corticosteroids

Towards personalized management of myasthenia gravis phenotypes: From the role of multi-omics to the emerging biomarkers and therapeutic targets

Predicting the onset, progression, and outcome of rare and chronic neurological diseases, i.e. neuromuscular diseases, is an important goal for both clinicians and researchers and should guide clinical decision-making and personalized treatment plans. A prime example is myasthenia gravis (MG), an antibody-mediated disease that affects multiple components of the postsynaptic membrane, impairing neuromuscular transmission and producing fatigable muscle weakness. MG is characterized by several clinical phenotypes, defined by a broad spectrum of factors, which have contributed to the current lack of consensus on the optimal management and treatments of this disease and its related phenotypes (subtypes). This represents a crucial challenge in MG and encourages a revolutionary change in diagnostic, prognostic and therapeutic guidelines. Emerging factors, such as demographic, clinical and pathophysiological factors, must also be considered. Consequently, the different MG phenotypes are characterized by precise biological signatures, which could represent appropriate biomarkers and targets. Here we describe and discuss these new concepts, highlighting that, thanks to multi-omics technologies, the identification of emerging diagnostic/prognostic biomarkers, such as miRNAs, and the subsequent development of new diagnostic/therapeutic algorithms could be facilitated. The latter, in turn, could facilitate the management of different MG phenotypes also in a personalized manner. Limitations and advantages are also reported.

Treatment Approaches to Myasthenia Gravis and Obstructive Sleep Apnea: Case Report

Myasthenia gravis (MG) is a chronic autoimmune disease characterized by progressive weakness and skeletal muscle fatigue due to the destruction of acetylcholine receptors, causing an abnormality in the synaptic junction between innervation and muscle fibers. The treatment of patients with MG and obstructive sleep apnea (OSA) is positive pressure in the airway; however, the lack of adherence to the protocol can lead to increased morbidity. A known alternative treatment for OSA is the mandibular advancement device (MAD). The objective of the present report is to describe an emblematic case of a 50-year-old male patient with MG with sleep complaints and documented OSA, and his response to different treatment approaches.

Time to response with ravulizumab, a long-acting terminal complement inhibitor, in adults with anti-acetylcholine receptor antibody-positive generalized myasthenia gravis

BACKGROUND AND PURPOSE

The efficacy and safety of ravulizumab, a terminal complement C5 inhibitor, in adults with anti-acetylcholine receptor antibody-positive (AChR Ab+) generalized myasthenia gravis (gMG) were demonstrated in the CHAMPION MG study (NCT03920293). This analysis aimed to characterize the latency to onset of a clinically meaningful therapeutic effect for ravulizumab.

METHODS

Post hoc analysis of data collected for up to 60 weeks from CHAMPION MG was performed to assess the timing of response to ravulizumab. Response was analyzed based on reductions of ≥2 and ≥3 points (minimal clinically important differences [MCIDs]) in Myasthenia Gravis-Activities of Daily Living (MG-ADL) and Quantitative Myasthenia Gravis (QMG) total scores, respectively, and on more rigorous reductions of ≥3 and ≥5 points, respectively. Time to first response was assessed using the Kaplan-Meier product-limit method.

RESULTS

The median (95% confidence interval) time to first response was 2.1 (2.1-2.6) and 4.1 (2.3-10.0) weeks for reductions of ≥2 and ≥3 points in MG-ADL total score, respectively (n = 139), and 4.1 (2.1-10.0) and 18.3 (11.0-33.4) weeks for reductions of ≥3 and ≥5 points in QMG total score, respectively (n = 134). Cumulative response rates at Week 60 (data cut-off) were 88% and 82% for ≥2- and ≥3-point MG-ADL score reductions, respectively, and 86% and 59% for ≥3- and ≥5-point QMG score reductions, respectively.

CONCLUSIONS

The median times to MCID with ravulizumab treatment in patients with AChR Ab+ gMG were ~2 weeks and ~4 weeks based on MCID MG-ADL and QMG total score reductions, respectively.

Characterizing Myasthenia Gravis Symptoms, Exacerbations, and Crises From Neurologist's Clinical Notes Using Natural Language Processing

Background Myasthenia gravis (MG) is a rare, autoantibody neuromuscular disorder characterized by fatigable weakness. Real-world evidence based on administrative and structured datasets regarding MG may miss important details related to the clinical encounter. Examination of free-text clinical progress notes has the potential to illuminate aspects of MG care. Objective The primary objective was to examine and characterize neurologist progress notes in the care of individuals with MG regarding the prevalence of documentation of clinical subtypes, antibody status, symptomatology, and MG deteriorations, including exacerbations and crises. The secondary objectives were to categorize MG deteriorations into practical, objective states as well as examine potential sources of clinical inertia in MG care. Methods We performed a retrospective, cross-sectional analysis of de-identified neurologist clinical notes from 2017 to 2022. A qualitative analysis of physician descriptions of MG deteriorations and a discussion of risks in MG care (risk for adverse effects, risk for clinical decompensation, etc.) was performed. Results Of the 3,085 individuals with MG, clinical subtypes and antibody status identified included gMG (n = 400; 13.0%), ocular MG (n = 253; 8.2%), MG unspecified (2,432; 78.8%), seropositivity for acetylcholine receptor antibody (n = 441; 14.3%), and MuSK antibody (n = 29; 0.9%). The most common gMG manifestations were dysphagia (n = 712; 23.0%), dyspnea (n = 626; 20.3%), and dysarthria (n = 514; 16.7%). In MG crisis patients, documentation of difficulties with MG standard therapies was common (n = 62; 45.2%). The qualitative analysis of MG deterioration types includes symptom fluctuation, symptom worsening with treatment intensification, MG deterioration with rescue therapy, and MG crisis. Qualitative analysis of MG-related risks included the toxicity of new therapies and concern for worsening MG because of changing therapies. Conclusions This study of neurologist progress notes demonstrates the potential for real-world evidence generation in the care of individuals with MG. MG patients suffer fluctuating symptomatology and a spectrum of clinical deteriorations. Adverse effects of MG therapies are common, highlighting the need for effective, less toxic treatments.

Drug Use Patterns in Myasthenia Gravis: A Real-World Population-Based Cohort Study in Italy

Background: In the context of a comparative study of efficacy and safety of drugs used in rare neuromuscular and neurodegenerative diseases (CAESAR-call AIFA_FV_2012-13-14), we assessed the use patterns of drugs indicated for myasthenia gravis (MG). Methods: A retrospective cohort study was conducted based on administrative healthcare data. For a cohort of MG patients, prevalent and incident use of pyridostigmine (Py) and other indicated drugs in the first year after case identification was evaluated. Prevalent combined use of major therapies (azathioprine (Az), prednisone (Pr), vitamin D (Vd)) stratified by Py use was assessed, and a comparison between therapies at the time of MG identification and during the first year of follow-up was performed. Results: We included 2369 MG patients between 2013 and 2019. Among them, prevalent and incident Py users were 38.4% and 22.0%, respectively. In the first year of follow-up, the use of Pr was observed in 74.5% of Py prevalent users and in 82.0% of Py incident users, respectively; the use of Az was observed in 24.9% and 23.0%, respectively; and the use of Vd was observed in 53.3% and 48.2%, respectively. Among 910 Py prevalent users, 13.1% also used Az, Pr, and Vd, while 15.3% used none of these. Among 938 non-Py users, 2.7% used Az, Pr, and Vd, while 53.8% used none of these. During the first year, an increase in combined therapies was evident in incident Py users. Conclusions: Our results suggest that, for some MG patients, there may be a need for treatments that combine a rapid onset of benefit with long-term and consistent disease control. These issues may be addressed by the new treatments currently being developed. To date, more studies are needed to address the heterogeneity, quality, and generalizability of the existing data and to evaluate patterns of use, efficacy, and safety of new or emerging therapies for MG.

Efgartigimod in generalized myasthenia gravis: A real-life experience at a national reference center

BACKGROUND AND PURPOSE

Inhibition of the neonatal Fc receptor (FcRn) for IgG is a promising new therapeutic strategy for antibody-mediated disorders. We report our real-life experience with efgartigimod (EFG) in 19 patients with generalized myasthenia gravis (gMG) along a clinical follow-up of 14 months.

METHODS

EFG was administered according to the GENERATIVE protocol (consisting of a Fixed period of two treatment cycles [given 1 month apart] of four infusions at weekly intervals, followed by a Flexible period of re-cycling in case of worsening). Eight patients were positive for acetylcholine receptor antibody, four for muscle-specific tyrosine kinase antibody, and two for lipoprotein-related protein 4 antibody, and five were classified as triple negative. Efficacy of EFG was assessed by the Myasthenia Gravis Activities of Daily Living, Myasthenia Gravis Composite, and Quantitative Myasthenia Gravis scales.

RESULTS

Fifty-three percent of patients needed three treatment cycles, 26% needed four, and 21% needed five along the 14-month clinical follow-up. Meaningful improvement was observed at the end of each cycle with the clinical scores adopted. EFG had a dramatic effect on disease course, as during the year before treatment eight of 19 patients (42%) were hospitalized, and 15 of 19 (79%) needed treatment with plasma exchange or immunoglobulins; three of 19 (16%) were admitted to the intensive care unit. During EFG, none of the patients was hospitalized and only one patient required plasma exchange and intravenous immunoglobulins. No major side effects or infusion-related reactions occurred.

CONCLUSIONS

We observed that EFG was safe and modified significantly the course of the disease along a 14-month follow-up. Our experience strengthens the role of FcRn inhibition as an effective new tool for long-term treatment of gMG.

Myasthenia gravis-Pathophysiology, diagnosis, and treatment

Myasthenia gravis (MG) is an autoimmune disease characterized by dysfunction of the neuromuscular junction resulting in skeletal muscle weakness. It is equally prevalent in males and females, but debuts at a younger age in females and at an older age in males. Ptosis, diplopia, facial bulbar weakness, and limb weakness are the most common symptoms. MG can be classified based on the presence of serum autoantibodies. Acetylcholine receptor (AChR) antibodies are found in 80%-85% of patients, muscle-specific kinase (MuSK) antibodies in 5%-8%, and <1% may have low-density lipoprotein receptor-related protein 4 (Lrp4) antibodies. Approximately 10% of patients are seronegative for antibodies binding the known disease-related antigens. In patients with AChR MG, 10%-20% have a thymoma, which is usually detected at the onset of the disease. Important differences between clinical presentation, treatment responsiveness, and disease mechanisms have been observed between these different serologic MG classes. Besides the typical clinical features and serologic testing, the diagnosis can be established with additional tests, including repetitive nerve stimulation, single fiber EMG, and the ice pack test. Treatment options for MG consist of symptomatic treatment (such as pyridostigmine), immunosuppressive treatment, or thymectomy. Despite the treatment with symptomatic drugs, steroid-sparing immunosuppressants, intravenous immunoglobulins, plasmapheresis, and thymectomy, a large proportion of patients remain chronically dependent on corticosteroids (CS). In the past decade, the number of treatment options for MG has considerably increased. Advances in the understanding of the pathophysiology have led to new treatment options targeting B or T cells, the complement cascade, the neonatal Fc receptor or cytokines. In the future, these new treatments are likely to reduce the chronic use of CS, diminish side effects, and decrease the number of patients with refractory disease.

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.

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.

[Clinical effect of different immunosuppressive treatment regimens in children with ocular myasthenia gravis: a retrospective analysis]

OBJECTIVES

To investigate the clinical effect of different immunosuppressive treatment regimens in children with ocular myasthenia gravis (OMG).

METHODS

A retrospective analysis was conducted on 130 children with OMG who were treated in the Department of Neurology, Jiangxi Children's Hospital, from February 2018 to February 2023. According to the treatment regimen, they were divided into four groups: glucocorticoid (GC) group (n=29), mycophenolate mofetil (MMF) group (GC+MMF; n=33), methotrexate (MTX) group (GC+MTX; n=30), and tacrolimus (FK506) group (GC+FK506; n=38). Treatment outcomes and adverse reactions were compared among the groups.

RESULTS

After 3 months of treatment, the FK506 group had significantly lower scores of Myasthenia Gravis Quantitative Scale and Myasthenia Gravis-Specific Activities of Daily Living than the other three groups (P<0.05). After 3 months of treatment, the FK506 group had a significantly lower dose of prednisone than the GC group, and after 6 and 9 months of treatment, the MMF, MTX, and FK506 groups had a significantly lower dose of prednisone than the GC group (P<0.05). After 12 months of treatment, the MMF, MTX, and FK506 groups had a significantly lower incidence rate of GC-related adverse reactions than the GC group (P<0.05).

CONCLUSIONS

For children with OMG, the addition of various immunosuppressants can reduce the dosage of GC and adverse reactions. Among them, FK506 shows superior efficacy compared to other immunosuppressants in the early treatment of OMG.

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.

Real world study on prevalence, treatment and economic burden of myasthenia gravis in Italy

The purpose of this study was to investigate the epidemiology, management, and economic burden of myasthenia gravis in settings of real clinical practice. The analysis used administrative databases covering around 12 million subjects across Italy and included all adult patients with hospitalization discharge diagnosis or active exemption code for myasthenia gravis or with ≥1 pyridostigmine prescription from 2011 to 2018. The estimated prevalence of myasthenia gravis during 2018 was in the range 13.5-29.3/100,000 people (depending on the criteria applied), corresponding to 8190-17,728 alive patients, when reproportioning data to the entire Italian population. Overall 4397 patients with myasthenia gravis (mean age 61.7 years, 46.6% males) were included. A large pyridostigmine use was observed (84.0%-46.8% from 1st to 3rd year of follow-up), followed by corticosteroids (54.5%-44.6% from 1st to 3rd year of follow-up) and non-steroidal immunosuppressants (16% over follow-up). Total direct healthcare costs for myasthenia gravis were 4-times higher than those of the general population (€3771 and €869, respectively), and up to 9-fold increased when considering patients with exacerbation (€7827). These findings showed the epidemiologic burden of myasthenia gravis and the complexity of the therapeutic management for the affected patients, with large use of treatments and elevated healthcare expenditures.

Percutaneous Electrical Nerve Stimulation (PENS) for Infrapatellar Saphenous Neuralgia Management in a Patient with Myasthenia gravis (MG)

Myasthenia gravis is a neuromuscular transmission disorder characterized by weakness of the cranial and skeletal muscles, however, neuropathies are extremely rare. In this case report we present a case of a 61-year-old man diagnosed Myasthenia gravis who came to our attention due to a 1 week of acute deep pain [NPRS 8/10] in the anterior and medial right knee which occurred during walking [NPRS 8/10] or stair climbing [NPRS 9/10]. A complete medical record and clinical examination based on physical exploration and ultrasound assessment confirmed a infrapatellar saphenous neuralgia. Therapeutic interventions included Percutaneous nerve electrical stimulation combined with pain neuroscience education, neural mobilization of the saphenous nerve and quadriceps resistance exercises. After 4 weeks, pain intensity [NRPS = 1/10], knee functionality [OKS = 41/48] and lower limb functionality [LLFI = 80%] were notably improved, nevertheless, fatigue [RPE = 2/10] was similar than baseline. At 2 months of follow-up, the effect on intensity of pain NRPS [0/10] and functionality OKS [40/48] and LLFI [82%] was maintained, however, no significant clinical changes were detected on perceived fatigue RPE Scale [2/10]. Despite the important methodological limitations of this study, our case report highlights the efficacy of percutaneous electrical nerve stimulation combined with physical agents modalities for pain and functionality of infrapatellar saphenous neuralgia in the context of Myasthenia gravis.

Reduced quality of life in myasthenia gravis patients: A study on 185 patients from China

Aims

To explore the quality of life (QOL) in patients with myasthenia gravis (MG) and factors associated with QOL.

Methods

This observational study included patients with MG diagnosed at the First Affiliated Hospital of Fujian Medical University between January 2020 and March 2022. The QOL of patients was evaluated with the 15-item Myasthenia Gravis Quality of Life (MG-QOL15). Current MG severity was evaluated with MGFA grade, MG-ADL score, MGC score, and MGFA Postintervention Status. The data about gender, age of onset, subgroup, antibodies, age, duration, education, employment state, marital status, skeletal muscle affected, thymic histology, and current treatment methods of the patient were collected.

Results

A total of 185 patients [72 males (38.9%), aged 45.2 years (14-77)] with MG were enrolled. Age at onset was 38.3 ± 17.9 years, and disease duration was 87.9 months (0-672). The median MG-QOL15 score was 12.5 (0-58). The item "have trouble using my eyes" was the highest scoring item in both ocular and generalized patients with MG. The MG-QOL15 score was significantly different among patients with OMG (9.2 ± 9.4, n = 63), GMG (9.0 ± 8.8, n = 22), and BMG (15.4 ± 14.2, n = 100) (P = 0.018). Patients with BMG had higher MG-QOL15 scores than OMG (P = 0.001) and GMG (P = 0.009), but there was no significant difference between OMG and GMG (P = 0.467). The MG-QOL15 score was significantly lower in patients who had undergone thymectomy (9.7 ± 9.8, n = 58) compared to those who had not (13.8 ± 13.4, n = 127, P = 0.022). MG-QOL15 score was significantly lower in patients who underwent thymectomy compared to those who did not (9.7 ± 9.8, n = 58 vs. 13.8 ± 13.4, n = 127, P = 0.022). MG-QOL15 score was different among MGFA grades (Remission: 5.2 ± 5.4, n = 41; I: 11.3 ± 10, n = 61; II: 11.6 ± 11.1, n = 40; III: 18.1 ± 12.1, n = 29; and IVa: 30.1 ± 20, n = 14, P < 0.001). There was no significant difference between patients in MGFA grade I and II (P = 0.896), and there was no significant difference between patients in MGFA grade III and IVa (P = 0.052). MG-ADL (P < 0.001) and MGC (P < 0.001) were positively correlated with MG-QOL15. Men had higher MG-QOL15 than women (P = 0.094), and LOMG had higher MG-QOL15 than EOMG (P = 0.072). Multivariate linear regression identified that higher MG-ADL (P < 0.001), higher MGC (P = 0.02), and poor employment status (P = 0.045) were independently associated with higher MG-QOL15.

Conclusion

Having trouble using the eyes accounted for the highest score in MG-QOL15, eye symptoms affect QOL more than limb weakness in MG. Daily life activity, disease severity, and employment status were associated with patients' QOL. Adequate treatment should be applied to improve QOL, while mild symptoms can be accepted. Men and patients over the age of 50 years of onset may need more attention.

Serum neurofilament light chain in myasthenia gravis subgroups: An exploratory cohort and case-Control study

Background

This study aimed to evaluate the association of neurofilament light chain (Nfl) with neuromuscular destruction and disease severity in the serum of patients with myasthenia gravis (MG).

Materials and methods

Sera from 134 patients with MG with varying degrees of disease severity and autoantibody (Abs) status were analyzed and compared to controls in a cross-sectional design. Prospectively, we additionally measured serum NfL (sNfl) levels in patients with MG longitudinally for up to 3 years. Based on linear regression, differences between patients and controls were assessed. With correlation coefficients and mixed linear regression, the association among sNfl levels, socio-demographics, disease activity (Quantitative Myasthenia Gravis (QMG) score and Myasthenia Gravis Activities of Daily Living (MG-ADL) scale), Abs-status (acetylcholine receptor antibody (AChR-Abs), muscle-specific receptor tyrosine kinase antibody (MuSK-Abs), lipoprotein-related protein 4 (LRP4), and seronegative), Abs titer, treatment regime (pyridostigmine, steroids, and immunosuppressive therapies), and thymectomy were investigated.

Results

sNfl levels were higher in patients with MG compared to controls (median: 11.2 vs. 7.88), where sNfl levels were highest in anti-AChR-Abs positive patients (median 12.6), followed by anti-MuSK-Abs positive, anti-LRP4-Abs positive, and seronegative patients. Adjusting for age and sex, sNfl levels of patients with MG were on average 35% higher compared to controls (35.1, 95% CI: 8.4;68.3) and highest for patients with seronegative MG (44.35; 95% CI 16.47; 78.90). We found no relevant relationship between individual changes in sNfl and changes in QMG and MG-ADL scores.

Conclusion

sNfl levels are higher in patients with MG than in controls but were not consistently associated with clinical severity. Thus, sNfl is not a suitable biomarker to monitor individual disease progression in patients with MG.

Rituximab in Myasthenia Gravis- Experience from a Low- and Middle-Income Country (LMIC) Setting

BACKGROUND

Myasthenia gravis (MG) is an immune-mediated disorder of the neuromuscular junction. About 10% are refractory to immunosuppressive therapy.

AIMS

To analyze the response of patients with generalized MG to rituximab.

METHODS AND MATERIALS

A retrospective review of patients with MG who received rituximab was carried out (n = 13, M:F = 6:7, mean age: 44.84 ± 15.73 years). Myasthenia Gravis Foundation of America (MGFA), MGFA post-intervention status (MGFA-PIS), and Myasthenia Gravis Status and Treatment Intensity (MGSTI) were assessed before and after rituximab.

RESULTS

The duration of MG was 104.07 ± 92.25 months. Before rituximab, the MGFA was IIA/IIB/IIIA/IIIB/IVB/V in 1/1/2/6/2/1 patients and MGSTI was four in eight patients and six in three patients. The mean duration of follow up was 20.92 ± 14.06 months (range, 4 to 42 months). Dose reduction or discontinuation of cholinesterase inhibitors could be achieved 12 patients. Complete stable remission (CSR) and pharmacologic remission (PR) were achieved in one and four patients respectively and five patients had minimal manifestations. Most patients attained level 0, 1 or 2 MGSTI at last follow up. No rituximab infusion-related adverse events were noted. Three patients had exacerbation of MG between one to five weeks after rituximab administration. Three patients died, one each due to a cardiac event unrelated to MG or treatment, complications related to myasthenic crisis, and coronavirus disease.

CONCLUSIONS

Rituximab was effective in bringing about remission in MG and can be considered as a first-line agent. However, it has to be administered under close supervision as some patients develop exacerbation of MG akin to steroid-induced worsening.

CAR-T Regulatory (CAR-Treg) Cells: Engineering and Applications

Regulatory T cells are critical for maintaining immune tolerance. Recent studies have confirmed their therapeutic suppressive potential to modulate immune responses in organ transplant and autoimmune diseases. However, the unknown and nonspecific antigen recognition of polyclonal Tregs has impaired their therapeutic potency in initial clinical findings. To address this limitation, antigen specificity can be conferred to Tregs by engineering the expression of transgenic T-cell receptor (TCR) or chimeric antigen receptor (CAR). In contrast to TCR Tregs, CAR Tregs are major histocompatibility complex (MHC) independent and less dependent on interleukin-2 (IL-2). Furthermore, CAR Tregs maintain Treg phenotype and function, home to the target tissue and show enhanced suppressive efficacy compared to polyclonal Tregs. Additional development of engineered CAR Tregs is needed to increase Tregs' suppressive function and stability, prevent CAR Treg exhaustion, and assess their safety profile. Further understanding of Tregs therapeutic potential will be necessary before moving to broader clinical applications. Here, we summarize recent studies utilizing CAR Tregs in modulating immune responses in autoimmune diseases, transplantation, and gene therapy and future clinical applications.

Adverse Side Effects Associated with Corticosteroid Therapy: A Study in 39 Patients with Generalized Myasthenia Gravis

Background

The tolerability of high-dose oral corticosteroids in patients with generalized myasthenia gravis (gMG) has not been systematically assessed. We evaluated adverse side effects (ASEs) of corticosteroid treatment in patients with gMG.

Material/Methods

Retrospective analysis was conducted of ASEs reported as being related to corticosteroid treatment in 39 patients with gMG who were treated with oral corticosteroids for ≥1 year.

Results

Median (interquartile range [IQR]) age was 60 (21) years, 53.8% of patients were women, and 66.7% were aged ≤65 years. Median (IQR) prednisone treatment duration was 14 (2) months; median (IQR) daily dose was 40 (15) mg. The median number of ASEs reported as corticosteroid-related was 2/patient (IQR, 1). Pre-diabetes and weight gain were most common (each 43.6% of patients). Bruising, insomnia, and osteoporosis were more prevalent in patients aged >65 years, while irritability, osteopenia, and pre-diabetes were more common in patients aged ≤65 years, although differences were not statistically significant. Irritability and weight gain were more prevalent in women (P=0.010 for irritability); osteoporosis and pre-diabetes more common in men (P=0.015 for osteoporosis). ASEs were generally more common in the high-dose prednisone group (>30 mg/day), but were only statistically significant for irritability (P=0.001).

Conclusions

Corticosteroid-related ASEs were common in patients with gMG. Some of these ASEs can have serious medical consequences, and certain ASEs appeared to be associated with specific patient characteristics. Demographics and comorbidities of patients with gMG must be carefully considered before corticosteroid initiation. Potential ASEs, such as unanticipated osteoporosis in men, require extra vigilance.

Calprotectin as potential novel biomarker in myasthenia gravis

Myasthenia gravis (MG) is the most common autoimmune disease affecting the neuromuscular junction by specific autoantibodies. The etiology of MG and its heterogeneity in clinical courses are poorly understood, although it was recently shown that gut microbial dysbiosis plays a critical role. Since levels of Calprotectin (CLP) seem to correlate with level of dysbiosis, we hypothesize that CLP may serve as potential disease activity biomarker in MG. Sera from 251 patients with MG and 90 controls were analyzed in an explorative, cross-sectional design. Prospectively, we tested CLP levels in MG patients up to 3 years. Association of CLP levels with socio-demographics, disease activity (quantitative myasthenia gravis (QMG) score, myasthenia gravis-specific Activities of Daily Living scale (MG-ADL)), antibody (Abs) status, history of myasthenic crisis, treatment regime, and history of thymectomy were investigated using univariate analysis. Mean baseline serum levels of CLP were significantly higher in MG patients compared to controls (4.3 μg/ml vs. 2.1 μg/ml; p < 0.0001). Higher levels of CLP were associated with a higher clinical disease severity measured by MGFA classification and QMG score. Nevertheless, the only weak correlation of CLP with clinical outcome parameters needs confirmation in future studies. Currently, there are no validated blood biomarkers for MG. The significantly elevated CLP and mild correlation with parameters of disease activity suggests that CLP holds promise as a biomarker for measurement of individual disease severity.

The Safety Factor for Neuromuscular Transmission: Effects of Dimethylsulphoxide, Cannabinoids and Synaptic Homeostasis

BackgroundIn myasthenia gravis, impaired postsynaptic sensitivity to acetylcholine results in failure of neuromuscular transmission and fatiguing muscle weakness.ObjectiveDevelop an ex vivo muscle contraction assay to test cannabinoids and other substances that might act on the myasthenic neuromuscular junction to restore control of the muscle.MethodsTubocurarine was added to an ex vivo, mouse phrenic nerve-hemidiaphragm muscle preparation to reduce acetylcholine sensitivity. This produced a myasthenia-like decrement in twitch force during a train of 10 nerve impulses (3 / sec). Endplate potential (EPP) recordings were used to confirm and extend the findings.ResultsSurprisingly, addition to the bath of dimethylsulphoxide (DMSO), at concentrations as low as 0.1%(v/v), partially reversed the decrement in nerve-evoked force. Intracellular electrophysiology, conducted in the presence of tubocurarine, showed that DMSO increased the amplitudes of both the spontaneous miniature EPP (MEPP) and the (nerve-evoked) EPP. In the absence of tubocurarine (synaptic potentials at physiological levels), an adaptive fall in quantal content negated the DMSO-induced rise in EPP amplitude. The effects of cannabinoid receptor agonists (solubilized with DMSO) in the contraction assay do not support their further exploration as useful therapeutic agents for myasthenia gravis. CP 55,940 (a dual agonist for cannabinoid receptor types 1 and 2) reversed the beneficial effects of DMSO.Conclusions:We demonstrate a powerful effect of DMSO upon quantal amplitude that might mislead pharmacological studies of synaptic function wherever DMSO is used as a drug vehicle. Our results also show that compounds targeting impaired neuromuscular transmission should be tested under myasthenic-like conditions, so as to avoid confounding effects of synaptic homeostasis.

Emerging drugs for the treatment of myasthenia gravis

Introduction: Advances in understanding the immune pathomechanisms in myasthenia gravis (MG) allow for the development of novel targeted immune therapies. By working at specific points in the immunopathogenesis, these agents have the potential to provide rapid and efficacious responses compared to conventional immunosuppressive therapy (IST), addressing unmet needs and consequently are a research priority.Areas covered: This paper reviews the advances in MG treatment modalities with their scientific rationale. A search of clinicaltrials.gov and a literature search of PubMed from January 2015 to the end of June 2021 was done using the search terms: MG, treatment, immune targets to obtain information on recent developments of complement inhibitors, FcRn receptor inhibitors, direct and indirect B cell inhibitors, CAR and CAAR- T cell therapy, and hematopoietic stem cell transplantation. Specific agents in various phases of clinical development, evidence from ongoing trials and potential roadblocks are examined.Expert opinion: Despite several promising novel agents, existing data as to the timing of initiation and duration of treatment, long-term safety profile and utility in certain patient subsets are limited and require further research. Despite these considerations, the future of MG treatment is transitioning from broad-spectrum IST toward precise, target-driven and personalized immunotherapy.

Accuracy of patient-reported data for an online patient registry of autoimmune myasthenia gravis and Lambert-Eaton myasthenic syndrome

Disorders of the neuromuscular junction (NMJ) comprise a spectrum of rare diseases causing muscle fatigability and weakness, leading to life-long effects on quality of life. We established the Dutch-Belgian registry for NMJ disorders, based on a unique combination of patient- and physician-reported information. Information on natural course, disease burden, prevalence of complications and comorbidity is collected through patient-reported standardized questionnaires and verified using medical documentation. Currently, the registry contains information of 565 Myasthenia Gravis (MG) patients and 38 Lambert-Eaton myasthenic syndrome (LEMS) patients, constituting approximately 25% (MG) and 80% (LEMS) of patients in the Netherlands. This is a very large registry, with the highest participation rate per capita. In addition to confirming many disease characteristics previously described in the literature, this registry provides several novel insights. The reported rate of potentially corticosteroid-related comorbidity, including hypertension, heart disease, osteoporosis and type 2 diabetes was high, emphasizing the need to commence corticosteroid-sparing immune suppressive treatment as soon as possible. The reported rate of other auto-immune diseases is far higher than previously expected: 27% of MG and 38% of LEMS patients, and a surprisingly high number of MG patients (47%) is unaware of their antibody status. In conclusion, this registry provides a valuable collection of information regarding MG and LEMS disease course. Continuous collection of annual follow-up data will provide further longitudinal insights in disease burden, course and treatment effect.

Incidence, mortality, and economic burden of myasthenia gravis in China: A nationwide population-based study

Background

Myasthenia gravis (MG) is the most common primary disorder of neuromuscular transmission, but the incidence of MG in China is unknown. We conducted the first nationwide study to determine the incidence and mortality rates of MG in all age groups at the national level in China.

Methods

This national population-based registry study is based on the database of the Hospital Quality Monitoring System of National Health Commission, which covers 1665 hospitals providing myasthenia gravis care in 31 provinces and municipalities across China. 94,638 hospital admissions for 59,243 myasthenia gravis patients were identified from January 1st, 2016 to December 31st, 2018. Myasthenia gravis was identified by ICD-10 codes (G70). Incidence of myasthenia gravis was stratified by age, sex, and province.

Findings

Of 59,243 patients, 30,503 individuals with myasthenia gravis were newly diagnosed. Age and sex adjusted incidence of myasthenia gravis was 0.68 per 100,000 person-years, with highest in the age group of 70–74 years. The incidence in females was 0.76 per 100,000 and 0.60 per 100,000 in males. The admission mortality rate was 14.69‰. Respiratory failure was the leading cause of death in patients with myasthenic crisis. There were 14,840 patients with thymomas, encompassing 14,636 (26.5%) adults and 204 (7.1%) juveniles. 9453 (63.7%) patients with thymomas underwent thymomectomy. The median length of hospital stay was 8 days (interquartile range (IQR) 4 to 15 days) with median hospitalization cost $1037 (IQR $493 to $2925). The Basic Medical Insurance was the most common payment method, covering 67.4% of patients.

Interpretation

The age and sex adjusted incidence of MG was 0.68 per 100,000 person-years in China. The admission mortality rate was 14.69‰. Most cases of new onset MG occurred in the seventh decade of life.

Funding

National Science Foundation of China (91642205, and 81830038); Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing