What Is in the Neuromuscular Junction Literature?

ABSTRACT: This update covers recommendations for myasthenia gravis (MG) in patients with coronavirus 2019 disease as well as reports of the clinical features of patients with MG and coronavirus 2019. Updated advisory committee recommendations for the use of thymectomy in generalized MG are also provided. Other MG topics include lipoprotein receptor-4 and agrin antibody associations, factors influencing conversion of ocular to generalized MG, the use of rituximab for more recent onset disease, immunoglobulins for maintenance therapy, and fatigue and depression.

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.

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

BACKGROUND: Generalised myasthenia gravis is a chronic, unpredictable, and debilitating rare disease, often accompanied by high treatment burden and with an unmet need for more efficacious and well tolerated treatments. Zilucoplan is a subcutaneous, self-administered macrocyclic peptide complement C5 inhibitor. We aimed to assess safety, efficacy, and tolerability of zilucoplan in patients with acetylcholine receptor autoantibody (AChR)-positive generalised myasthenia gravis. METHODS: RAISE was a randomised, double-blind, placebo-controlled, phase 3 trial that was done at 75 sites in Europe, Japan, and North America. We enrolled patients (aged 18-74 years) with AChR-positive generalised myasthenia gravis (Myasthenia Gravis Foundation of America disease class II-IV), a myasthenia gravis activities of daily living (MG-ADL) score of least 6, and a quantitative myasthenia gravis score of at least 12. Participants were randomly assigned (1:1) to receive subcutaneous zilucoplan 0·3 mg/kg once daily by self-injection, or matched placebo, for 12 weeks. The primary efficacy endpoint was change from baseline to week 12 in MG-ADL score in the modified intention-to-treat population (all randomly assigned patients who received at least one dose of study drug and had at least one post-dosing MG-ADL score). Safety was mainly assessed by the incidence of treatment-emergent adverse events (TEAEs) in all patients who had received at least one dose of zilucoplan or placebo. This trial is registered at ClinicalTrials.gov, NCT04115293. An open-label extension study is ongoing (NCT04225871). FINDINGS: Between Sept 17, 2019, and Sept 10, 2021, 239 patients were screened for the study, of whom 174 (73%) were eligible. 86 (49%) patients were randomly assigned to zilucoplan 0·3 mg/kg and 88 (51%) were assigned to placebo. Patients assigned to zilucoplan showed a greater reduction in MG-ADL score from baseline to week 12, compared with those assigned to placebo (least squares mean change -4·39 [95% CI -5·28 to -3·50] vs -2·30 [-3·17 to -1·43]; least squares mean difference -2·09 [-3·24 to -0·95]; p=0·0004). TEAEs occurred in 66 (77%) patients in the zilucoplan group and in 62 (70%) patients in the placebo group. The most common TEAE was injection-site bruising (n=14 [16%] in the zilucoplan group and n=8 [9%] in the placebo group). Incidences of serious TEAEs and serious infections were similar in both groups. One patient died in each group; neither death (COVID-19 [zilucoplan] and cerebral haemorrhage [placebo]) was considered related to the study drug. INTERPRETATION: Zilucoplan treatment showed rapid and clinically meaningful improvements in myasthenia gravis-specific efficacy outcomes, had a favourable safety profile, and was well tolerated, with no major safety findings. Zilucoplan is a new potential treatment option for a broad population of patients with AChR-positive generalised myasthenia gravis. The long-term safety and efficacy of zilucoplan is being assessed in an ongoing open-label extension study. FUNDING: UCB Pharma.

Incidence, Prevalence, Hospitalization Rates, and Treatment Patterns in Myasthenia Gravis: A 10-Year Real-World Data Analysis of German Claims Data.

BACKGROUND: Myasthenia gravis (MG) is a rare chronic autoimmune disease caused by autoantibodies directed against postsynaptic antigens of the neuromuscular junction. Over the last decades, increasing incidence and prevalence rates have been reported. Epidemiological data on prevalence and incidence in Germany are lacking. Furthermore, the MG treatment landscape is rapidly changing due to the continued approval of novel monoclonal antibodies. METHOD: This is a retrospective study assessing incidence, prevalence, and hospitalization rates of MG as well as treatment patterns in Germany over 10 years based on medical claims data covering 6.1 million insured persons. RESULTS: Between 2011 and 2020, the prevalence rate of MG increased from 15.7 to 28.2 per 100,000 person-years. The age-adjusted incidence rate was 2.8 per 100,000 person-years within the study period (95% confidence interval, 2.43-3.22) and decreased dramatically in 2020, the year of the COVID-19 pandemic. Similarly, the hospitalization rate fluctuated within the study period but reached an overall low of 8.3% in 2020 (mean hospitalization rate 11.5%). Treatment patterns showed that most MG patients are treated with base therapy. However, crisis intervention is necessary for 2-5% of MG patients, and therapeutic monoclonal antibodies, including rituximab and eculizumab, are increasingly used. CONCLUSION: This is the first study on MG prevalence and incidence rates in Germany. Data show an increase in prevalence by 1.8-fold over 10 years. Decreasing incidence and hospitalization rates in 2020 hint at the impact of the COVID-19 pandemic. Treatment patterns in MG are changing with the advent of therapeutic monoclonal antibodies in this indication.

Clinical course and outcome of Covid-19 in patients with myasthenia gravis.

OBJECTIVES: To analyze the prognosis and outcomes of COVID-19 in patients with MG and to determine factors associated with COVID-19 severity in patients with MG. METHODS: Information concerning COVID-19 occurrence in patients with MG was collected in this single-center observational study. Univariate and multivariate analyses were used to identify factors associated with severe Covid-19. RESULTS: Two hundred seventy-five of the 386 records of MG were included in this study. Eighty-two (29.8%) patients had concurrent COVID-19 . The patients' mean age was 50.3 ± 1.6 years, and the mean duration of MG was 6.7 ± 5.4 years. MG was diagnosed after COVID-19 in five cases. Covid-19 was mild in 45 patients (54.9%), moderate in 23 (28.1%), and severe in 14 (17.07%), while mortality occurred in four of the severe cases (4.9%). Three of the exitus patients were receiving rituximab therapy. Pre-Covid MG Activity of Daily Living (MG-ADL) severity scores were significantly high in severe cases. A history of myasthenic crisis was also higher in severe cases. Similarly, univariate and multivariate analyses revealed an association between severe COVID-19 and myasthenic crisis history and high pre-Covid MG-ADL. The type of MG treatment had no independent effect on COVID-19 severity. CONCLUSION: The vast majority of the MG patients made a good recovery from Covid-19. The risk of severe COVID-19 is high in patients with high MG-ADL severity scores and a history of myasthenic crisis.

Pneumonia in myasthenia gravis: Microbial etiology and clinical management.

Introduction: Patients with myasthenia gravis (MG) are prone to the development of pneumonia due to the long-term immunotherapies they receive and a tendency for aspiration. Pneumonia remains a risk factor for MG worsening and is the most prevalent cause of mortality in MG patients. Classification of the pathogens involved and exploration of the risk factors for mechanical ventilation (MV) could aid in improving clinical outcomes. Methods: Between January 2013 and October 2022, we performed an inpatient database review for MG patients with pneumonia concurrence in a tertiary research center specializing in neuromuscular disorders. The clinical and microbiological characteristics of 116 MG patients with pneumonia were retrospectively analyzed. Results: In our cohort, 90.32% (112/124) of organisms were bacteria and 42.86% (48/112) of pathogenic bacteria were carbapenem-resistant. A high abundance of Epstein-Barr virus (EBV) was detected using next-generation sequencing (NGS) in 12 patients, while cytomegalovirus (CMV) was detected in 8 patients. Non-fermentative Gram-negative bacilli were the most prevalent microorganisms, in which ampicillin, sulfamethoxazole-trimethoprim (SMZ-TMP), piperacillin, cefoperazone, ceftazidime, and cefepime may have an anti-infectious effect. Moreover, peripheral lymphocyte percentage [odds ratio (OR) 0.88, 95% CI 0.75-0.96, p = 0.02] and serum globulin (OR 1.16, 95% CI 1.02-1.35, p = 0.03) were significantly associated with the risk of MV demand. Discussion: Our identification of the microbial etiology of pneumonia in MG patients may provide future perspectives on accurate antibiotic options and enable early interventions when risk factors are present.

Anemia in female patients with myasthenia gravis.

Myasthenia gravis (MG) is the most common autoimmune neuromuscular disorder, and is more common in women than in men. Anemia is also more common in women. The purpose of this study was to investigate factors associated with anemia and the negative impact of anemia in female MG patients. We investigated factors related to MG and anemia in 215 female patients with MG, who were attending the MG clinic of Keio Hospital between January and December 2021. We statistically evaluated clinical factors related to anemia in patients with and without anemia. Eighty-five patients (40%) had anemia in the past, and 130 patients did not have anemia in the past. There were no significant differences in age at study, age at MG onset, body mass index, or frequency of autoantibodies between the anemia and non-anemia groups. MG severity evaluated by the MG Foundation of America classification was greater in the anemia group than in the non-anemia group. History of anemia was associated with immunosuppressive treatment, such as prednisolone and calcineurin inhibitor treatment. There was a correlation between hemoglobin levels and the MG-quality of life score. Long term immunosuppressive therapy can cause anemia in female MG patients. Anemia may negatively affect the quality of life of female MG patients.

Safety of mRNA COVID-19 vaccines in patients with well-controlled myasthenia gravis.

INTRODUCTION/AIMS: Data on safety and tolerability of the vaccines against severe acute respiratory virus coronavirus-2 (SARS-CoV-2, or coronavirus disease-2019 [COVID-19]) in patients with myasthenia gravis (MG) are currently limited. In this study we investigated the safety of mRNA-based two-dose vaccination in a cohort of patients with MG. METHODS: This investigation was a prospective observational study of messenger RNA (mRNA)-based vaccines administered to patients with MG with stable disease. Local and systemic reactogenicity after injection was monitored for each dose administered. The patients were categorized and clinically assessed following the recommendations of the Myasthenia Gravis Foundation of America. RESULTS: Thirty-six males and 55 females (mean age at first vaccine dose, 58.8 years; standard deviation, = 17.1 years) received vaccines. Seventy-two patients (79.1%) were taking one or more immunosuppressant(s). The most frequent adverse effects were injection-site pain, fatigue, myalgia, chills, fever, and headache. Local and systemic reactions were transient; 58.2% of the patients developed one or more reaction(s). There were no anaphylactic reactions. None of the patients had a myasthenic crisis, and two developed a mild deterioration compared with their Quantitative Myasthenia Gravis baseline score. The clinical outcome scores showed no exacerbation of MG symptoms. Patients over 65 years of age developed fewer adverse effects. COVID-19 vaccination did not induce clinical exacerbation in stable patients with MG, regardless of their age, sex, history of myasthenic crisis, or whether they were taking immunosuppressants. DISCUSSION: Our data are consistent with the mRNA COVID-19 vaccine being well tolerated in patients with well-controlled MG. The findings may contribute to decisions in vaccination campaigns in the future.

New-onset myasthenia gravis after mRNA SARS-CoV-2 vaccination: a case series.

BACKGROUND: Myasthenia gravis (MG) is an autoimmune disease that targets acetylcholine receptor (AChR) of the neuromuscular junction. New-onset MG after SARS-CoV-2 vaccination has rarely been reported. CASE PRESENTATION: We report about three patients who presented new-onset myasthenia gravis after receiving mRNA SARS-CoV-2 vaccination. The patients were all males and older than 55 years. All the patients presented with ocular and bulbar symptoms. The interval between vaccine administration and MG onset ranged from 3 days after the first dose to 10 days after the second dose. All the patients had elevated serum AChR antibodies and responded to pyridostigmine. Two out of three patients were successfully treated with IVIG or plasma exchange and with long-term immunosuppression. CONCLUSIONS: MG is a rare disease; clinicians should be aware of possible new-onset MG after SARS-CoV-2 vaccination, especially with the current recommendation of booster doses. The hyperstimulation of the innate immune system or the exacerbation of a subclinical pre-existing MG could be possible explanations.

Retrospective study on the safety of COVID-19 vaccination in myasthenia gravis.

INTRODUCTION/AIM: Given the lack of information on safety of coronavirus disease 2019 (COVID-19) vaccination in myasthenia gravis (MG) patients, we aimed to review our experience after surveying patients, as part of routine clinical practice, to ensure that advice on safety is accurate. METHODS: We performed a retrospective chart review of MG patients from the Prosserman Family Neuromuscular Clinic at the Toronto General Hospital who received two injections of any COVID-19 vaccine from February to August 2021. Demographic data were abstracted from the patient medical records. We assessed changes in the severity of MG using the virtual Myasthenia Gravis Impairment Index (vMGII), the simple single question (SSQ), and Patient Acceptable Symptom State (PASS). We also assessed adverse effects after vaccination. RESULTS: We included 200 patients with a mean age of 64.3 ± 13.9 y, 51.5% were men, and 82% had generalized MG. The vMGII, SSQ, and PASS scores remained stable after each vaccine dose, and at last follow-up. Of the patients, 60% reported an adverse reaction after the first injection, and 56% after the second. The most common adverse reactions reported were local pain at the injection site, fatigue, headache, and fever. DISCUSSION: COVID-19 vaccinations were well tolerated in MG patients and were not associated with worsening severity of their MG. The prevalence of vaccine-related adverse reactions was the same as in the general population.

Generalized myasthenia gravis patients infected with COVID-19 should continue eculizumab.

Eculizumab, a humanized monoclonal antibody, is a complement inhibitor indicated for refractory generalized myasthenia gravis (MG). However, there are limited data on the safety of eculizumab for MG during coronavirus disease 2019 (COVID-19) infection. We report a case in which eculizumab was continued for MG after contracting COVID-19, followed by a favorable outcome.

Predictive factors for a severe course of COVID-19 infection in myasthenia gravis patients with an overall impact on myasthenic outcome status and survival.

BACKGROUND AND PURPOSE: Myasthenia gravis (MG) patients could be a vulnerable group in the pandemic era of coronavirus 2019 (COVID-19) mainly due to respiratory muscle weakness, older age and long-term immunosuppressive treatment. We aimed to define factors predicting the severity of COVID-19 in MG patients and risk of MG exacerbation during COVID-19. METHODS: We evaluated clinical features and outcomes after COVID-19 in 93 MG patients. RESULTS: Thirty-five patients (38%) had severe pneumonia and we recorded 10 deaths (11%) due to COVID-19. Higher forced vital capacity (FVC) values tested before COVID-19 were shown to be protective against severe infection (95% CI 0.934-0.98) as well as good control of MG measured by the quantified myasthenia gravis score (95% CI 1.047-1.232). Long-term chronic corticosteroid treatment worsened the course of COVID-19 in MG patients (95% CI 1.784-111.43) and this impact was positively associated with dosage (p = 0.005). Treatment using azathioprine (95% CI 0.448-2.935), mycophenolate mofetil (95% CI 0.91-12.515) and ciclosporin (95% CI 0.029-2.212) did not influence the course of COVID-19. MG patients treated with rituximab had a high risk of death caused by COVID-19 (95% CI 3.216-383.971). Exacerbation of MG during infection was relatively rare (15%) and was not caused by remdesivir, convalescent plasma or favipiravir (95% CI 0.885-10.87). CONCLUSIONS: As the most important predictors of severe COVID-19 in MG patients we identified unsatisfied condition of MG with lower FVC, previous long-term corticosteroid treatment especially in higher doses, older age, the presence of cancer, and recent rituximab treatment.

The use of eculizumab in ventilator-dependent myasthenia gravis patients.

INTRODUCTION/AIMS: Eculizumab has been shown to be efficacious in acetylcholine receptor antibody-positive (AChR+ ) Myasthenia Gravis Foundation of America (MGFA) class II, III, and IV generalized myasthenia gravis (gMG) patients. However, it has not been studied in MGFA class V gMG patients. METHODS: We report three AChR+ , refractory, MGFA class V gMG patients treated with eculizumab. MGFA class, MG-Composite (MGC) score and MG Activities of Daily Living (MG-ADL) score were assessed before and after eculizumab. RESULTS: Two of three gMG patients, refractory to intravenous immunoglobulin, plasmapheresis, prednisone, and (in one case) rituximab, showed a robust response to eculizumab with marked improvement in MGFA, MG-ADL, and MGC measures. The third patient showed a partial response to eculizumab but remained on noninvasive ventilation and gastrostomy intubation. Patients 1 and 2 achieved minimal manifestation status at week 4 and week 6, respectively, and showed continued improvement on MG-ADL and MGC scores through weeks 55 and 43, respectively, with eculizumab. The third patient showed a partial response at week 10, followed by a slight decline in his MG-ADL score, but noted a slow but an incomplete improvement afterward on MG-ADL and MGC scores, possibly due to delayed eculizumab infusion. DISCUSSION: Eculizumab may play a role in the treatment of patients with MGFA class V, refractory gMG. Larger studies are required to provide further evidence.

COVID-19 in Refractory Myasthenia Gravis- A Case Report of Successful Outcome.

This is a brief report of a patient who has refractory Myasthenia Gravis, on multiple long-term immunosuppressive therapies and contracted COVID-19 during this 2020 pandemic. She was quarantined for total of 14 days and recovered successfully without any complications (no myasthenia exacerbation or crisis, no COVID-19 related complications), with no changes to her immunosuppressive therapy. Treatment of MG patients with COVID-19 needs to be tailored to individual patient.

Transient acetylcholine receptor-related myasthenia gravis, post multisystem inflammatory syndrome in children (MIS-C) temporally associated with COVID-19 infection.

We report on a unique case of a 7-year-old girl with new onset ocular myasthenia gravis shortly after recovery from multisystem inflammatory syndrome in children (MIS-C) temporally associated with SARS-CoV-2 infection. The diagnosis of myasthenia gravis was based on suggestive symptoms of fatigable bilateral orbital ptosis, diplopia, positive ocular cold compression test and serum acetylcholine receptor antibody positivity, as well as a favourable treatment response to pyridostigmine. The addition of corticosteroids and methotrexate resulted in complete resolution of the ocular signs.

Myasthenia gravis associated with novel coronavirus 2019 infection: A report of three cases.

Several neurological presentations have been reported following coronavirus 2019 (COVID-19) infection. This case report describes three myasthenia gravis (MG) patients presented following COVID-19 infection. We report three adult patients with myasthenic Gravis and COVID-19 infection. The patients are between 38 and 61 years old. Case 1 is a 61-year-old woman with progressive dysphagia, nasal speech, ocular ptosis, diplopia, and proximal muscle weakness for 10 days. She had a COVID-19 infection 6 weeks ago. Case 2 is a 57-year-old man with clinical symptoms of muscular fatigability, diplopia, ptosis, and dysphagia for a week and a positive COVID-19 infection 10 days ago. Case 3 is a 38-year-old woman with fatigability, ptosis, dysphagia, and a diagnosis of COVID-19 infection 4 weeks ago. All patients had a positive RT-PCR for COVID-19 infection by nasopharyngeal swab test and a high-level acetylcholine receptor antibody in the serum. All patients were treated with pyridostigmine and prednisolone with a favorable outcome. MG may appear following COVID-19 infection, and the role of molecular mimicry and latent MG activation should be considered the cause of the disease onset.