Myasthenia gravis: Historical achievements and the "golden age" of clinical trials

Defective autophagy and autophagy activators in myasthenia gravis: a rare entity and unusual scenario

Myasthenia gravis (MG) is an autoimmune disease of the neuromuscular junction (NMJ) that results from autoantibodies against nicotinic acetylcholine receptors (nAchRs) at NMJs. These autoantibodies are mainly originated from autoreactive B cells that bind and destroy nAchRs at NMJs preventing nerve impulses from activating the end-plates of skeletal muscle. Indeed, immune dysregulation plays a crucial role in the pathogenesis of MG. Autoreactive B cells are increased in MG due to the defect in the central and peripheral tolerance mechanisms. As well, autoreactive T cells are augmented in MG due to the diversion of regulatory T (Treg) cells or a defect in thymic anergy leading to T cell-mediated autoimmunity. Furthermore, macroautophagy/autophagy, which is a conserved cellular catabolic process, plays a critical role in autoimmune diseases by regulating antigen presentation, survival of immune cells and cytokine-mediated inflammation. Abnormal autophagic flux is associated with different autoimmune disorders. Autophagy regulates the connection between innate and adaptive immune responses by controlling the production of cytokines and survival of Tregs. As autophagy is involved in autoimmune disorders, it may play a major role in the pathogenesis of MG. Therefore, this mini-review demonstrates the potential role of autophagy and autophagy activators in MG.Abbreviations: Ach, acetylcholine; Breg, regulatory B; IgG, immunoglobulin G; MG, myasthenia gravis; NMJ, neuromuscular junction; ROS, reactive oxygen species; Treg, regulatory T; Ubl, ubiquitin-like.

Myasthenia gravis: the future is here

Myasthenia gravis (MG) stands as a prototypical antibody-mediated autoimmune disease: it is dependent on T cells and characterized by the presence of autoantibodies targeting proteins located on the postsynaptic surface of skeletal muscle, known as the neuromuscular junction. Patients with MG exhibit a spectrum of weakness, ranging from limited ocular muscle involvement to life-threatening respiratory failure. Recent decades have witnessed substantial progress in understanding the underlying pathophysiology, leading to the delineation of distinct subcategories within MG, including MG linked to AChR or MuSK antibodies as well as age-based distinction, thymoma-associated, and immune checkpoint inhibitor-induced MG. This heightened understanding has paved the way for the development of more precise and targeted therapeutic interventions. Notably, the FDA has recently approved therapeutic inhibitors of complement and the IgG receptor FcRn, a testament to our improved comprehension of autoantibody effector mechanisms in MG. In this Review, we delve into the various subgroups of MG, stratified by age, autoantibody type, and histology of the thymus with neoplasms. Furthermore, we explore both current and potential emerging therapeutic strategies, shedding light on the evolving landscape of MG treatment.

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

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

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

BACKGROUND AND OBJECTIVES

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

METHODS

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

RESULTS

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

DISCUSSION

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

TRIAL REGISTRATION INFORMATION

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

CLASSIFICATION OF EVIDENCE

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

[Clinical and epidemiological characteristics of myasthenia in the Altai region]

OBJECTIVE

To analyze the epidemiological and clinical characteristics of myasthenia gravis (MG) in the Altai region (AR).

MATERIAL AND METHODS

One hundred and twenty-two patients with a verified diagnosis of MG, living in the AR, took part in the study. To collect data, a questionnaire was developed, the data of which formed the basis for the study. Data analysis was carried out using the Statistica 12 program (Stat. Soft, Inc.).

RESULTS

The group of patients studied makes up 14-28% of the expected number of patients with MG in AR. In general, patients with late onset of the disease predominated in the group (71 people versus 51). A predominance of women was revealed in the group with an early onset of the disease, while in the group with a late onset the ratio of men and women levels out. The identification of two peaks in the age of onset of the disease in women, which was not observed in the group of men, was a feature of the clinical course of MG in AR. In the study group, the generalized form of MG was more common; the onset of the disease in most patients began with weakness of the external eye muscles. In most patients, MG was associated with antibodies to the acetylcholine receptor, but seronegative cases were also noted. A rarer frequency of thymus pathology has been established. An analysis was carried out of the factors that preceded the onset of MG, among which the most common was viral infection.

CONCLUSION

The clinical and epidemiological features of MG in AR are described. Further monitoring of clinical and epidemiological data on MG in AR will make it possible to clarify the regional characteristics of risk factors for the development and course of the disease.

Unveiling the Multifaceted Problems Associated with Dysrhythmia

Dysrhythmia is a term referring to the occurrence of spontaneous and repetitive changes in potentials with parameters deviating from those considered normal. The term refers to heart anomalies but has a broader meaning. Dysrhythmias may concern the heart, neurological system, digestive system, and sensory organs. Ion currents conducted through ion channels are a universal phenomenon. The occurrence of channel abnormalities will therefore result in disorders with clinical manifestations depending on the affected tissue, but phenomena from other tissues and organs may also manifest themselves. A similar problem concerns the implementation of pharmacotherapy, the mechanism of which is related to the impact on various ion currents. Treatment in this case may cause unfavorable effects on other tissues and organs. Drugs acting through the modulation of ion currents are characterized by relatively low tissue specificity. To assess a therapy's efficacy and safety, the risk of occurrences in other tissues with similar mechanisms of action must be considered. In the present review, the focus is shifted prominently onto a comparison of abnormal electrical activity within different tissues and organs. This review includes an overview of the types of dysrhythmias and the basic techniques of clinical examination of electrophysiological disorders. It also presents a concise overview of the available pharmacotherapy in particular diseases. In addition, the authors review the relevant ion channels and their research technique based on patch clumping.

Randomized Double-Blind Placebo-Controlled Trial of the Corticosteroid-Sparing Effects of Immunoglobulin in Myasthenia Gravis

BACKGROUND AND OBJECTIVES

Myasthenia gravis (MG) is an autoimmune disease characterized by dysfunction at the neuromuscular junction. Treatment frequently includes corticosteroids (CSs) and IV immunoglobulin (IVIG). This study was conducted to determine whether immune globulin (human), 10% caprylate/chromatography purified (IGIV-C) could facilitate CS dose reduction in CS-dependent patients with MG.

METHODS

In this randomized double-blind placebo-controlled trial, CS-dependent patients with MG (Myasthenia Gravis Foundation of America Class II-Iva; AChR+) received a loading dose of 2 g/kg IGIV-C over 2 days (maximum 80 g/d) or placebo at week 0 (baseline). Maintenance doses (1 g/kg IGIV-C or placebo) were administered every 3 weeks through week 36. Tapering of CS was initiated at week 9 and continued through week 36 unless the patient worsened (quantitative MG score ≥4 points from baseline). CS doses were increased (based on the current CS dose) in patients who worsened. Patients were withdrawn if worsening failed to improve within 6 weeks or if a second CS increase was required. The primary efficacy end point (at week 39) was a ≥50% reduction in CS dose. Secondary and safety end points were assessed throughout the study and follow-up (weeks 42 and 45). The study results and full protocol are available at clinicaltrials.gov/ct2/show/NCT02473965.

RESULTS

The primary end point (≥50% reduction in CS dose) showed no significant difference between the IGIV-C treatment (60.0% of patients) and placebo (63.3%). There were no significant differences for secondary end points. Safety data indicated that IGIV-C was well tolerated.

DISCUSSION

In this study, IGIV-C was not more effective than placebo in reducing daily CS dose. These results suggest that the effects of IGIV-C and CS are not synergistic and may be mechanistically different.

TRIAL REGISTRATION INFORMATION

The trial was registered on clinicaltrialsregister.eu (EudraCT #: 2013-005099-17) and clinicaltrials.gov (identifier NCT02473965).

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that IVIG infusions in adult patients with MG do not increase the percentage of patients achieving a ≥50% reduction in corticosteroid dose compared with placebo.

Heterogeneity of Acetylcholine Receptor Autoantibody-Mediated Complement Activity in Patients With Myasthenia Gravis

BACKGROUND AND OBJECTIVES

Autoantibodies targeting the acetylcholine receptor (AChR), found in patients with myasthenia gravis (MG), mediate pathology through 3 mechanisms: complement-directed tissue damage, blocking of the acetylcholine binding site, and internalization of the AChR. Clinical assays, used to diagnose and monitor patients, measure only autoantibody binding. Consequently, they are limited in providing association with disease burden, understanding of mechanistic heterogeneity, and monitoring therapeutic response. The objective of this study was to develop a cell-based assay that measures AChR autoantibody-mediated complement membrane attack complex (MAC) formation.

METHODS

An HEK293T cell line-modified using CRISPR/Cas9 genome editing to disrupt expression of the complement regulator genes (CD46, CD55, and CD59)-was used to measure AChR autoantibody-mediated MAC formation through flow cytometry.

RESULTS

Serum samples (n = 155) from 96 clinically confirmed AChR MG patients, representing a wide range of disease burden and autoantibody titer, were tested along with 32 healthy donor (HD) samples. AChR autoantibodies were detected in 139 of the 155 (89.7%) MG samples through a cell-based assay. Of the 139 AChR-positive samples, autoantibody-mediated MAC formation was detected in 83 (59.7%), whereas MAC formation was undetectable in the HD group or AChR-positive samples with low autoantibody levels. MAC formation was positively associated with autoantibody binding in most patient samples; ratios (mean fluorescence intensity) of MAC formation to AChR autoantibody binding ranged between 0.27 and 48, with a median of 0.79 and an interquartile range of 0.43 (0.58-1.1). However, the distribution of ratios was asymmetric and included extreme values; 16 samples were beyond the 10-90 percentile, with high MAC to low AChR autoantibody binding ratio or the reverse. Correlation between MAC formation and clinical disease scores suggested a modest positive association (rho = 0.34, p = 0.0023), which included a subset of outliers that did not follow this pattern. MAC formation did not associate with exposure to immunotherapy, thymectomy, or MG subtypes defined by age-of-onset.

DISCUSSION

A novel assay for evaluating AChR autoantibody-mediated complement activity was developed. A subset of patients that lacks association between MAC formation and autoantibody binding or disease burden was identified. The assay may provide a better understanding of the heterogeneous autoantibody molecular pathology and identify patients expected to benefit from complement inhibitor therapy.

Clinical Significance of Serum Albumin and Implications of FcRn Inhibitor Treatment in IgG-Mediated Autoimmune Disorders

Serum albumin (SA), the most abundant soluble protein in the body, maintains plasma oncotic pressure and regulates the distribution of vascular fluid and has a range of other important functions. The goals of this review are to expand clinical knowledge regarding the functions of SA, elucidate effects of dysregulated SA concentration, and discuss the clinical relevance of hypoalbuminemia resulting from various diseases. We discuss potential repercussions of SA dysregulation on cholesterol levels, liver function, and other processes that rely on its homeostasis, as decreased SA concentration has been shown to be associated with increased risk for cardiovascular disease, hyperlipidemia, and mortality. We describe the anti-inflammatory and antioxidant properties of SA, as well as its ability to bind and transport a plethora of endogenous and exogenous molecules. SA is the primary serum protein involved in binding and transport of drugs and as such has the potential to affect, or be affected by, certain medications. Of current relevance are antibody-based inhibitors of the neonatal Fc receptor (FcRn), several of which are under clinical development to treat immunoglobulin G (IgG)-mediated autoimmune disorders; some have been shown to decrease SA concentration. FcRn acts as a homeostatic regulator of SA by rescuing it, as well as IgG, from intracellular degradation via a common cellular recycling mechanism. Greater clinical understanding of the multifunctional nature of SA and the potential clinical impact of decreased SA are needed; in particular, the potential for certain treatments to reduce SA concentration, which may affect efficacy and toxicity of medications and disease progression.

Pharmacotherapy of Generalized Myasthenia Gravis with Special Emphasis on Newer Biologicals

Myasthenia gravis (MG) is a chronic, fluctuating, antibody-mediated autoimmune disorder directed against the post-synaptic neuromuscular junctions of skeletal muscles, resulting in a wide spectrum of manifestations ranging from mild to potentially fatal. Given its unique natural course, designing an ideal trial design for MG has been wrought with difficulties and evidence in favour of several of the conventional agents is weak as per current standards. Despite this, acetylcholinesterases and corticosteroids have remained the cornerstones of treatment for several decades with intravenous immunoglobulins (IVIG) and therapeutic plasma exchange (PLEX) offering rapid treatment response, especially in crises. However, the treatment of MG entails long-term immunosuppression and conventional agents are viable options but take longer to act and have a number of class-specific adverse effects. Advances in immunology, translational medicine and drug development have seen the emergence of several newer biological agents which offer selective, target-specific immunotherapy with fewer side effects and rapid onset of action. Eculizumab is one of the newer agents that belong to the class of complement inhibitors and has been approved for the treatment of refractory general MG. Zilucoplan and ravulizumab are other agents in this group in clinical trials. Neisseria meningitis is a concern with all complement inhibitors, mandating vaccination. Neonatal Fc receptor (FcRn) inhibitors prevent immunoglobulin recycling and cause rapid reduction in antibody levels. Efgartigimod is an FcRn inhibitor recently approved for MG treatment, and rozanolixizumab, nipocalimab and batoclimab are other agents in clinical trial development. Although lacking high quality evidence from randomized clinical trials, clinical experience with the use of anti-CD20 rituximab has led to its use in refractory MG. Among novel targets, interleukin 6 (IL6) inhibitors such as satralizumab are promising and currently undergoing evaluation. Cutting-edge therapies include genetically modifying T cells to recognise chimeric antigen receptors (CAR) and chimeric autoantibody receptors (CAAR). These may offer sustained and long-term remissions, but are still in very early stages of evaluation. Hematopoietic stem cell transplantation (HSCT) allows immune resetting and offers sustained remission, but the induction regimens often involve serious systemic toxicity. While MG treatment is moving beyond conventional agents towards target-specific biologicals, lack of knowledge as to the initiation, maintenance, switching, tapering and long-term safety profile necessitates further research. These concerns and the high financial burden of novel agents may hamper widespread clinical use in the near future.

Eculizumab versus rituximab in generalised myasthenia gravis

OBJECTIVE

Myasthenia gravis (MG) is the most common autoimmune disorder affecting the neuromuscular junction. However, evidence shaping treatment decisions, particularly for treatment-refractory cases, is sparse. Both rituximab and eculizumab may be considered as therapeutic options for refractory MG after insufficient symptom control by standard immunosuppressive therapies.

METHODS

In this retrospective observational study, we included 57 rituximab-treated and 20 eculizumab-treated patients with MG to compare the efficacy of treatment agents in generalised, therapy-refractory anti-acetylcholine receptor antibody (anti-AChR-ab)-mediated MG with an observation period of 24 months. Change in the quantitative myasthenia gravis (QMG) score was defined as the primary outcome parameter. Differences between groups were determined in an optimal full propensity score matching model.

RESULTS

Both groups were comparable in terms of clinical and demographic characteristics. Eculizumab was associated with a better outcome compared with rituximab, as measured by the change of the QMG score at 12 and 24 months of treatment. Minimal manifestation of disease was more frequently achieved in eculizumab-treated patients than rituximab-treated patients at 12 and 24 months after baseline. However, the risk of myasthenic crisis (MC) was not ameliorated in either group.

INTERPRETATION

This retrospective, observational study provides the first real-world evidence supporting the use of eculizumab for the treatment of refractory, anti-AChR-ab positive MG. Nonetheless, the risk of MC remained high and prompts the need for intensified monitoring and further research effort aimed at this vulnerable patient cohort.

Therapeutic Plasma Exchange: For Cancer Patients

Therapeutic plasma exchange is used as a trial method for the treatment of cancer patients. Therapeutic plasma exchange uses in vitro technology to remove pathogenic factors in the plasma, returning the replacement and remaining components to the patient to facilitate cure. In the effort to explore new methods of cancer treatment, the introduction of therapeutic plasma exchange brings new hope for cancer treatment; however, the current evidence supporting therapeutic plasma exchange is controversial, and most of the evidence comes from observational studies, lacking large prospective randomized trials. Therefore, this review attempts to focus on the main indications of therapeutic plasma exchange for the treatment of tumors and their complications, including hematological tumors (multiple myeloma cast nephropathy and hyperviscosity syndrome), nervous system tumors (myasthenia gravis associated with thymoma, paraneoplastic neurological syndrome, Lambert–Eaton myasthenia syndrome, and anti-N-methyl-D-aspartate receptor encephalitis), overdose of chemotherapy drugs. In addition, the issues of side-effects and safety in the use of therapeutic plasma exchange are also discussed. However, well-designed prospective trials are needed to better define the role of therapeutic plasma exchange in cancer.

Early Flare-Ups of Myasthenia Gravis After Thoracoscopic Thymectomy in a Patient Recently Receiving BNT162b2 mRNA COVID-19 Vaccination

Myasthenia gravis (MG) is an autoimmune disorder characterized by abnormal neuromuscular transmission. The thymus is believed to play a key role in the pathogenesis of MG, and thymectomy has been an optional treatment for the disease. Relapse of MG after thymectomy has been reported. Exacerbations and new onset of MG following COVID-19 vaccination have also been documented. This report presents a case of a stable MG patient with recent COVID-19 vaccination experiencing flare-ups of symptoms shortly after video-assisted thoracoscopic (VATS) thymectomy. A 31-year-old female received the second dose of the BNT162b2 mRNA COVID-19 vaccine eight days before thymectomy and developed flare-ups of symptoms four days after the surgery. Although the substantial link between MG exacerbations post-thymectomy and pre-thymectomy COVID-19 vaccination cannot be concluded, this observation warrants further research.

The Eldest Female Case of Myasthenia Gravis with an Unusual Presentation: Aspiration Pneumonia as the Initial Manifestation

We report the eldest female case of myasthenia gravis (MG) that initially presented with aspiration pneumonia. A 91-year-old female with a high-grade fever and general malaise who had suffered from expectoration for several years was diagnosed with aspiration pneumonia. Thorough medical history taking and physical examination suggested the possibility of MG as a cause of aspiration pneumonia. Positive acetylcholine receptor antibody and waning phenomenon on a nerve conduction study confirmed the diagnosis. Treatment with intravenous immunoglobulin, prednisolone, and pyridostigmine resulted in a rapid improvement. Physicians should always consider the etiology of aspiration pneumonia to prevent further negative events.

Current and Upcoming Treatment Modalities in Myasthenia Gravis

ABSTRACT

Myasthenia gravis (MG) is one of the extensively studied autoimmune disorder. There has been a dramatic increase in research to further understand molecular pathogenesis of MG and clinical trials for new drugs in MG treatment in the past decade. This review article is to consolidate the available information in simple terms with students, residents, and fellows as target audience for easy learning and help application of this knowledge to clinical practice.

Pharmacological Management of Myasthenia Gravis: A Century of Expert Opinions in Cecil Textbook of Medicine

BACKGROUND

Advances in drug therapy for myasthenia gravis have had a significant impact on the quality of life and work potential of a substantial majority of affected persons and has contributed to a remarkable decrease in the frequency and severity of complications, hospitalizations, and mortality.

STUDY QUESTION

What are the milestones of the changes in the expert approach to the pharmacological management of myasthenia in the past century?

STUDY DESIGN

To determine the changes in the experts' approach to the management of myasthenia gravis, as presented in a widely used textbook in the United States.

DATA SOURCES

The chapters presenting the management of myasthenia gravis in the 26 editions of Cecil Textbook of Medicine published from 1927 to 2020.

RESULTS

Adequate feeding, absolute rest in bed, and "tonics" were the only interventions recommended for the care of patients with myasthenia gravis in 1927. Ephedrine and glycine were used in the early 1930s. Treatment with the anticholinesterases physostigmine and neostigmine was recommended in 1937, 3 years after Mary Walker discovered it in the United Kingdom. Immunosuppressant pharmacological interventions with prednisone and azathioprine have been considered the standard since 1975, and intravenous immune globulin was added to usual care in 1996. The newer immunosuppressant drugs mycophenolate, cyclosporine, and tacrolimus have expanded the arsenal since 2008, and the monoclonal antibodies rituximab and eculizumab have been mentioned in the textbooks published in 2012-2020. The first randomized clinical trial of drug therapy for myasthenia gravis was published in 1987.

CONCLUSIONS

The pharmacological management of myasthenia gravis was revolutionized by the epiphany of an astute clinician in the 1930s. Immunosuppressant treatment was a logical step once the autoimmune nature of the condition was established. The major therapeutic advances highlight the values of empiricism and persistent attention to detail in treating relatively rare chronic disorders.

Nomogram for short-term outcome assessment in AChR subtype generalized myasthenia gravis

BACKGROUND

An accurate prediction for prognosis can help in guiding the therapeutic options and optimizing the trial design for generalized myasthenia gravis (gMG). We aimed to develop and validate a predictive nomogram to assess the short-term outcome in patients with the anti-acetylcholine receptor (AChR) subtype gMG.

METHODS

We retrospectively reviewed 165 patients with AChR subtype gMG who were immunotherapy naïve at the first visit from five tertiary centers in China. The short-term clinical outcome is defined as the achievement of minimal symptom expression (MSE) at 12 months. Of them, 120 gMG patients from Huashan Hospital were enrolled to form a derivation cohort (n = 96) and a temporal validation cohort (n = 24) for the nomogram. Then, this nomogram was externally validated using 45 immunotherapy naïve AChR subtype gMG from the other four hospitals. Multivariate logistic regression was used to screen independent factors and construct the nomogram.

RESULTS

MSE was achieved in 70 (72.9%), 20 (83.3%), and 33 (73.3%) patients in the training, temporal validation, and external validation cohort, respectively. The duration ≤ 12 months (p = 0.021), ocular score ≤ 2 (p = 0.006), QMG score > 13 (p = 0.008), and gross motor score ≤ 9 (p = 0.006) were statistically associated with MSE in AChR subtype gMG. The nomogram has good performance in predicting MSE as the concordance indexes are 0.81 (95% CI, 0.72-0.90) in the development cohort, 0.944 (95% CI, 0.83-1.00) in the temporal validation cohort, and 0.773 (95% CI, 0.63-0.92) in the external validation cohort.

CONCLUSION

The nomogram achieved an optimal prediction of MSE in AChR subtype gMG patients using the baseline clinical characters.

Chronic immunoglobulin maintenance therapy in myasthenia gravis

BACKGROUND AND PURPOSE

Long-term treatment of myasthenia gravis (MG) includes symptomatic and course-modifying therapies that target the immune system. Recently, both intravenous immunoglobulin (IVIG) and subcutaneous immunoglobulin (SCIG) have emerged as viable options for chronic therapy, considering the favourable safety-efficacy profile and possible immunosuppressant sparing properties. The aim was to investigate the outcomes of the long-term care of generalized MG with immunoglobulin (Ig).

METHODS

This is a retrospective, repeated-measures design study. Charts of generalized MG patients, treated with IVIG/SCIG for at least 6 months, from January 2015 to January 2020, were analysed. The primary outcome was the mean change in Myasthenia Gravis Impairment Index (MGII) after treatment with Ig, comparing baseline to IVIG and SCIG treatment periods. Secondary outcomes included the changes in pyridostigmine, immunosuppressive medications and patient-reported outcome 'percentage of normal' (0%-100%).

RESULTS

Thirty-four patients were treated with chronic Ig therapy (30 IVIG/SCIG, three SCIG, one IVIG). The mean durations of IVIG and SCIG periods were 21.8 ± 19.4 (range 3-64) months and 19.5 ± 11.3 (range 5-45) months respectively. There was a significant reduction in MGII scores (27.7 ± 15.7 baseline; 22.0 ± 17.4 IVIG period; 19.5 ± 18.1 SCIG period; F = 17.9; d.f. = 1.7; P < 0.01), pyridostigmine and immunosuppressant use (P = 0.00). The outcome 'percentage of normal' had a significant positive association with both treatments (P = 0.00).

CONCLUSION

Our study results suggest that patients can be successfully transitioned to IVIG and from IVIG to SCIG in the chronic treatment of generalized MG with reductions in impairments and use of other medications and improvement in overall status with Ig therapy. Prospective, randomized studies are needed to clarify costs and comparative effectiveness.

Monoclonal Antibody-Based Therapies for Myasthenia Gravis

Myasthenia gravis (MG) is an autoimmune, neuromuscular disorder that produces disabling weakness through a compromise of neuromuscular transmission. The disease fulfills strict criteria of an antibody-mediated disease. Close to 90% of patients have antibodies directed towards the nicotinic acetylcholine receptor (AChR) on the post-synaptic surface of skeletal muscle and another 5% to the muscle-specific kinase, which is involved in concentrating the AChR to the muscle surface of the neuromuscular junction. Conventional treatments of intravenous immunoglobulin and plasma exchange reduce autoantibody levels to produce their therapeutic effect, while prednisone and immunosuppressives do so by moderating autoantibody production. None of these treatments were specifically developed for MG and have a range of adverse effects. The extensive advances in monoclonal antibody technology allowing specific modulation of biological pathways has led to a tremendous increase in the potential treatment options. For MG, monoclonal antibody therapeutics target the effector mechanism of complement inhibition and the reduction of antibody levels by FcRn inhibition. Antibodies directed against CD20 and signaling pathways, which support lymphocyte activity, have been used to reduce autoantibody production. Thus far, only eculizumab, an antibody against C5, has reached the clinic. We review the present status of monoclonal antibody-based treatments for MG that have entered human testing and offer the promise to transform treatment of MG.

Myasthenia Gravis Masquerading as an Idiopathic Unilateral Facial Paralysis (Bell's Palsy)-A Very Rare and Unique Clinical Find

Myasthenia gravis (MG) is an uncommon autoimmune neuromuscular junction disorder manifesting as fluctuating weakness of skeletal muscles. To add to its repertoire of mimicking a wide range of neurological disorders, the present case report is, to the best of our knowledge, the very first to describe MG masquerading as an idiopathic unilateral facial paralysis (Bell's palsy, BP). Our case report is distinct, highlights a novel clinical occurrence, offers new insights of how different neurological disorders may overlap with each other, and reminds neurologists to have a very broad and thorough comprehension for effective diagnoses and treatment plans. Several other conditions that produce facial nerve palsy identical to BP have also been discussed.

Guidance for the care of neuromuscular patients during the COVID-19 pandemic outbreak from the French Rare Health Care for Neuromuscular Diseases Network

In France, the epidemic phase of COVID-19 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) began in February 2020 and resulted in the implementation of emergency measures and a degradation in the organization of neuromuscular reference centers. In this special context, the French Rare Health Care for Neuromuscular Diseases Network (FILNEMUS) has established guidance in an attempt to homogenize the management of neuromuscular (NM) patients within the French territory. Hospitalization should be reserved for emergencies, the conduct of treatments that cannot be postponed, check-ups for which the diagnostic delay may result in a loss of survival chance, and cardiorespiratory assessments for which the delay could be detrimental to the patient. A national strategy was adopted during a period of 1 to 2 months concerning treatments usually administered in hospitalization. NM patients treated with steroid/immunosuppressants for a dysimmune pathology should continue all of their treatments in the absence of any manifestations suggestive of COVID-19. A frequently asked questions (FAQ) sheet has been compiled and updated on the FILNEMUS website. Various support systems for self-rehabilitation and guided exercises have been also provided on the website. In the context of NM diseases, particular attention must be paid to two experimental COVID-19 treatments, hydroxycholoroquine and azithromycin: risk of exacerbation of myasthenia gravis and QT prolongation in patients with pre-existing cardiac involvement. The unfavorable emergency context related to COVID-19 may specially affect the potential for intensive care admission (ICU) for people with NMD. In order to preserve the fairest medical decision, a multidisciplinary working group has listed the neuromuscular diseases with a good prognosis, usually eligible for resuscitation admission in ICU and, for other NM conditions, the positive criteria suggesting a good prognosis. Adaptation of the use of noninvasive ventilation (NIV) make it possible to limit nebulization and continue using NIV in ventilator-dependent patients.