Therapeutic Plasma Exchange in Myasthenia Gravis: A Systematic Literature Review and Meta-Analysis of Comparative Evidence

Antigen-specific immune therapy (CNP-106) for treatment of generalised myasthenia gravis: rationale and design of first-in-human randomised controlled trial

Introduction

Myasthenia gravis (MG) is a T cell-dependent B cell-mediated autoimmune disease with pathogenic antibodies directed against components of the acetylcholine receptor (AChR). Current therapies do not address the root cause of the disease (autoimmune recognition of AChR) and are associated with possible serious side effects. Therefore, new therapeutic options targeting antigen-specific autoimmunity are needed. COUR nanoparticle (CNP-106) is an antigen-specific immune tolerance therapy directed to the AChR to stop the pathogenic driver of MG. Data from experimental models suggest the potential benefit of CNP-106 to patients by reprogramming the immune system to AChR and stopping the progression of the disease. The aim of this study is to determine the safety and preliminary efficacy of CNP-106 in AChR antibody-positive generalised MG subjects.

Methods and analysis

The outlined study is a multicentre Phase 1b/2a double-blind, randomised, placebo-controlled trial with an enrolment target of 54 AChR antibody-positive generalised MG subjects. The primary endpoint is safety and tolerability. Exploratory and secondary endpoints include disease-specific clinical scores, measures of quality of life and activities of daily living, antigen-specific T cells and AChR antibodies. Trial enrolment is anticipated to start in 2024.

Ethics and dissemination

The trial has ethical approval from the Central Institutional Review Boards and has clinical trial authorisation from the Food and Drug Administration. Trial results will be communicated to participants, presented at national and international meetings and published in peer-reviewed journals.

Trial registration number

NCT06106672.

Targeted Treatments for Myasthenia Gravis in Children and Adolescents

Myasthenia gravis (MG) is an antibody-mediated disorder of the neuromuscular junction affecting children and adults. MG is a treatable condition with most patients requiring immunosuppression for disease control and/or remission. Juvenile myasthenia gravis (JMG) is rare in comparison with adult-onset MG but given the same underlying pathophysiology, treatment strategies are similar to those in adults. Until recently, there were only a few randomised controlled trials (RCTs) for MG treatments in adults and none in children, and management strategies were primarily based on expert consensus. In addition, treatment options for refractory MG cases have been severely limited, resulting in poor long-term quality of life in such patients due to the significant disease burden. Recently, there have been several RCTs focussing on novel therapeutic strategies with potentially promising outcomes, suggesting a change in MG management over the coming years and access to more effective and faster-acting drugs for MG patients. This paper will review current and new MG treatments including efgartigimod, eculizumab, rozanolixizumab, ravulizumab, and zilucoplan, with a focus on juvenile myasthenia gravis.

New treatment strategies in Myasthenia gravis

Myasthenia gravis (MG) is a chronic autoimmune neuromuscular disorder characterized by muscle weakness and fatigue. The disease is primarily caused by antibodies targeting acetylcholine receptors (AChR) and muscle-specific kinase (MuSK) proteins at the neuromuscular junction. Traditional treatments for MG, such as acetylcholinesterase inhibitors, corticosteroids, and immunosuppressants, have shown efficacy but are often associated with significant long-term side effects and variable patient response rates. Notably, approximately 15% of patients exhibit inadequate responses to these standard therapies. Recent advancements in molecular therapies, including monoclonal antibodies, B cell-depleting agents, complement inhibitors, Fc receptor antagonists, and chimeric antigen receptor (CAR) T cell-based therapies, have introduced promising alternatives for MG treatment. These novel therapeutic approaches offer potential improvements in targeting specific immune pathways involved in MG pathogenesis. This review highlights the progress and challenges in developing and implementing these molecular therapies. It discusses their mechanisms, efficacy, and the potential for personalized medicine in managing MG. The integration of new molecular therapies into clinical practice could significantly transform the treatment landscape of MG, offering more effective and tailored therapeutic options for patients who do not respond adequately to traditional treatments. These innovations underscore the importance of ongoing research and clinical trials to optimize therapeutic strategies and improve the quality of life for individuals with MG.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Therapeutic Plasma Exchange in AChR-Ab Positive Generalized Myasthenia Gravis: A Real World Study About Its Early Response

Background

Since there is no clear priority or selection principle in the guidelines for myasthenia crisis, therapeutic plasma exchange (TPE) and intravenous immunoglobulin are often administered randomly. However, it should be more prudent in taking TPE due to its higher cost and risk. Studying its early response factors is crucial for managing myasthenia crisis and can improve medical and economic benefits.

Methods

A prospective observational study was conducted, and patients classified as having "impending myasthenia crisis" or experiencing a myasthenia crisis and treated by TPE were included. The primary endpoint was the response after TPE. Univariate logistic regression analysis and repeated measurement were performed to analyze factors related to TPE efficacy.

Results

A total of 30 patients who treated with TPE as their fast-acting treatments were enrolled. After TPE, those whose QMGs and/or MGCs decreased by ≥5 points or ≥30% of the baseline were judged as "response group", accounting for 66.67% (20/30). Respiratory symptoms had a response rate of 72.00% (18/25), showing the most remarkable improvement. Meanwhile, extraocular symptoms were the least sensitive, with only 8.00% (2/25) showing efficacy. Thymoma (100.00% vs 50.00%, P=0.002) and a high concentration of AChR-Ab (37.37 nmol/L vs 25.4 nmol/L, P=0.039) were common in the early response group. Repeated measures showed significant changes in AChR-Ab and CD19+ B cells before and after TPE (all with P < 0.05). After treatment, the CD19+ B cells tended to decrease in the response group.

Discussion

These results indicated that, for AChR-Ab positive generalized MG, TPE can quickly improve respiratory symptoms. Thymoma and a high concentration of AChR-Ab before TPE predict an early better response. Additionally, TPE may work by decreasing AChR-Ab levels and inducing immune regulation. Future prospective and randomized controlled studies are needed.

Promising therapies for the treatment of myasthenia gravis

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

Chimeric AQP4-based immunosorbent for highly-specific removal of AQP4-IgG from blood

Anti-aquaporin-4 autoantibodies (AQP4-IgG) are implicated in the pathogenesis of neuromyelitis optica spectrum disorders (NMOSD), and their removal from the blood circulation is considered to be an effective method for acute treatment. An ideal extracorporeal AQP4-IgG removal system should have high specificity, which means that it can selectively remove AQP4-IgG without affecting normal immunoglobulins. However, the conventional tryptophan immobilized column lacks sufficient specificity and cannot achieve this goal. In this study, we successfully prepared a fusion protein chimeric AQP4, which consists of the complete antigenic epitopes of human AQP4 and the constant region of scaffold protein DARPin. Chimeric AQP4 was expressed and purified from Escherichia coli, and then immobilized on agarose gel as a ligand for selective capture of AQP4-IgG immunosorbent. The prepared immunosorbent had a theoretical maximum adsorption capacity of 20.48 mg/g gel estimated by Langmuir isotherm. In vitro plasma perfusion tests demonstrated that the chimeric AQP4 coupled adsorbent had remarkable adsorption performance, and could eliminate more than 85 % of AQP4-IgG under the gel-to-plasma ratio of 1:50. Moreover, it exhibited high specificity because other human plasma proteins were not adsorbed in the dynamic adsorption experiment. These results suggest that the chimeric AQP4 coupled immunosorbent can provide a new approach for specific immunoadsorption (IA) treatment of NMOSD.

Myasthenia gravis: the changing treatment landscape in the era of molecular therapies

Myasthenia gravis (MG) is an autoimmune disorder that affects the neuromuscular junction, leading to muscle weakness and fatigue. MG is caused by antibodies against the acetylcholine receptor (AChR), the muscle-specific kinase (MuSK) or other AChR-related proteins that are expressed in the postsynaptic muscle membrane. The standard therapeutic approach for MG has relied on acetylcholinesterase inhibitors, corticosteroids and immunosuppressants, which have shown good efficacy in improving MG-related symptoms in most people with the disease; however, these therapies can carry a considerable burden of long-term adverse effects. Moreover, up to 15% of individuals with MG exhibit limited or no response to these standard therapies. The emergence of molecular therapies, including monoclonal antibodies, B cell-depleting agents and chimeric antigen receptor T cell-based therapies, has the potential to revolutionize the MG treatment landscape. This Review provides a comprehensive overview of the progress achieved in molecular therapies for MG associated with AChR antibodies and MuSK antibodies, elucidating both the challenges and the opportunities these therapies present to the field. The latest developments in MG treatment are described, exploring the potential for personalized medicine approaches.

Case report: Recovery from refractory myasthenic crisis to minimal symptom expression after add-on treatment with efgartigimod

Myasthenic crisis, a life-threatening exacerbation of myasthenia gravis, is a significant clinical challenge, particularly when refractory to standard therapies. Here, we described a case of myasthenic crisis in which the patient transitioned from refractory myasthenic crisis to minimal symptom expression after receiving add-on treatment with efgartigimod, a novel neonatal Fc receptor antagonist. A 54 years-old woman who was diagnosed with anti-acetylcholine receptor antibody-positive myasthenia gravis experienced respiratory failure necessitating mechanical ventilation. Despite aggressive treatment with plasmapheresis, intravenous immunoglobulins, and high-dose corticosteroids, her condition continued to deteriorate, culminating in persistent myasthenic crisis. Efgartigimod was administered as salvage therapy. Remarkable improvement in neuromuscular function was observed within days, allowing for successful weaning from mechanical ventilation. Over the subsequent weeks, the patient's symptoms continued to ameliorate, ultimately reaching a state of minimal symptom expression. Serial assessments of her serum anti-acetylcholine receptor antibody titer showed a consistent decline in parallel with this clinical improvement. This case highlights efgartigimod's potential as an effective therapeutic option for refractory myasthenic crisis, offering new hope for patients facing this life-threatening condition.

Successful Emergency Management of a Dog with Ventilator-Dependent Acquired Myasthenia Gravis with Immunoadsorption

A one-year-old, female intact Samoyed, 12.5 kg, was presented with coughing for 2 weeks, progressive appendicular and axial muscle weakness, megaesophagus and labored breathing for 5 days. There was no improvement with standard treatment. Acquired myasthenia gravis was suspected and the dog was referred with increasing dyspnea. At presentation, the dog showed a severely reduced general condition, was non-ambulatory and showed abdominal and severely labored breathing. A marked hypercapnia (PvCO2 = 90.1 mmHg) was present in venous blood gas analysis. The serum anti-acetylcholine receptor antibody test was consistent with acquired myasthenia gravis (2.1 nmol/L). The dog was anesthetized with propofol and mechanically ventilated with a Hamilton C1 ventilator. Immunoadsorption was performed with the COM.TEC® and ADAsorb® platforms and a LIGASORB® adsorber to eliminate anti-acetylcholine receptor antibodies. Local anticoagulation was performed with citrate. Treatment time for immunoadsorption was 1.5 h with a blood flow of 50 mL/min. A total plasma volume of 1.2 L was processed. Further medical treatment included intravenous fluid therapy, maropitant, esomeprazole, antibiotic therapy for aspiration pneumonia and neostigmine 0.04 mg/kg intramuscularly every 6 h for treatment of acquired myasthenia gravis. Mechanical ventilation was stopped after 12 h. A percutaneous gastric feeding tube was inserted under endoscopic control on day 2 for further medical treatment and nutrition. A second treatment with immunoadsorption was performed on day 3. Again, a total plasma volume of 1.2 L was processed. Immediately after this procedure, the dog regained muscle strength and was able to stand and to walk. After 6 days, the dog was discharged from the hospital. This is the first report of immunoadsorption for emergency management of a dog with acute-fulminant acquired myasthenia gravis. Immunoadsorption may be an additional option for emergency treatment in dogs with severe signs of acquired myasthenia gravis.

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

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

Plasma Exchange versus Intravenous Immunoglobulin in Worsening Myasthenia Gravis: A Systematic Review and Meta-Analysis with Special Attention to Faster Relapse Control

Currently used rescue interventions to prevent rapid myasthenic deterioration are plasma exchange (PLEX) and intravenous immunoglobulin (IVIG). We investigated the evidence to determine whether the two methods were interchangeable or whether one was superior to the other. This review was registered on PROSPERO (CRD42021285985). Only randomized controlled trials (RCTs) comparing the efficacy and safety of PLEX and IVIG in patients with moderate-to-severe myasthenia gravis (MG) were included. Five major databases were systematically searched (PubMed, CENTRAL, Embase, Scopus, and Web of Science). Odds ratios (OR) with 95% confidence intervals (CI) were calculated for adverse events and mean differences (MD) for changes in quantitative myasthenia gravis scores (QMG). Three RCTs met the inclusion criteria. Two investigating 114 patients in total were eligible for meta-analysis to analyze efficacy and safety. For the change in QMG score, the MD was -2.8 (95% CI: -5.614-0.113), with PLEX performing better. For adverse events, an OR of 1.04 was found (95% CI: 0.25-4.27). This study demonstrated a low risk of bias in evaluating treatment efficacy but indicated a high risk of bias in assessing procedural safety outcomes. Although the results did not show any significant difference, there was a tendency indicating faster efficacy of PLEX in the first two weeks of treatment. In such a critical clinical condition, this tendency may be clinically meaningful, but further studies should clarify this benefit.

Myasthenia Gravis: Novel Findings and Perspectives on Traditional to Regenerative Therapeutic Interventions

The prevalence of myasthenia gravis (MG), an autoimmune disorder, is increasing among all subsets of the population leading to an elevated economic and social burden. The pathogenesis of MG is characterized by the synthesis of autoantibodies against the acetylcholine receptor (AChR), low-density lipoprotein receptor-related protein 4 (LRP4), or muscle-specific kinase at the neuromuscular junction, thereby leading to muscular weakness and fatigue. Based on clinical and laboratory examinations, the research is focused on distinguishing MG from other autoimmune, genetic diseases of neuromuscular transmission. Technological advancements in machine learning, a subset of artificial intelligence (AI) have been assistive in accurate diagnosis and management. Besides, addressing the clinical needs of MG patients is critical to improving quality of life (QoL) and satisfaction. Lifestyle changes including physical exercise and traditional Chinese medicine/herbs have also been shown to exert an ameliorative impact on MG progression. To achieve enhanced therapeutic efficacy, cholinesterase inhibitors, immunosuppressive drugs, and steroids in addition to plasma exchange therapy are widely recommended. Under surgical intervention, thymectomy is the only feasible alternative to removing thymoma to overcome thymoma-associated MG. Although these conventional and current therapeutic approaches are effective, the associated adverse events and surgical complexity limit their wide application. Moreover, Restivo et al. also, to increase survival and QoL, further recent developments revealed that antibody, gene, and regenerative therapies (such as stem cells and exosomes) are currently being investigated as a safer and more efficacious alternative. Considering these above-mentioned points, we have comprehensively reviewed the recent advances in pathological etiologies of MG including COVID-19, and its therapeutic management.

Myasthenia gravis and independent risk factors for recurrent infection: a retrospective cohort study

BACKGROUND

Approximately 10% to 20% of myasthenia gravis (MG) patients have experienced a myasthenic crisis (MC), which contributes to morbidity and mortality. MC triggered by infection is associated with poor outcomes. However, there is a lack of prognostic factors that clinicians can utilize to target interventions for preventing recurrent infection-triggered MC. This study aimed to characterize clinical manifestations, comorbidities, and biochemical profiles associated with recurrent infection-triggered MC in MG patients.

METHODS

This retrospective study included 272 MG patients hospitalized with an infection requiring at least 3 days of antibiotics from January 2001 to December 2019. Patients were further stratified into non-recurrent or recurrent infection groups. Clinical features such as gender, age, concomitant diseases, acetylcholine receptor antibodies and biochemical data (including electrolytes and coagulants), muscle strength of pelvic and shoulder girdle, bulbar and respiratory function, management with an endotracheal tube, Foley catheter, or plasmapheresis, duration of hospitalization, and culture pathogens were recorded.

RESULTS

The recurrent infection group was significantly older than the non-recurrent group (median age, 58.5 versus 52.0 years). Pneumonia was the most common infection and Klebsiella pneumoniae was the most common pathogen. The presence of concomitant diabetes mellitus, activated partial thromboplastin time prolongation, the duration of hospitalization, and hypomagnesaemia were independently associated with recurrent infection. The presence of deep vein thrombosis, thymic cancer, and electrolyte imbalances i.e., hypokalemia, and hypoalbuminemia were significantly associated with a risk for infection. The influence of endotracheal intubation, anemia, and plasmapheresis during hospitalization were inconsistent.

CONCLUSIONS

The independent risk factors for recurrent infections in MG patients identified in this study include the presence of concomitant diabetes mellitus, hypomagnesaemia, activated partial thromboplastin time prolongation, and longer duration of hospitalization, highlighting the need for targeted interventions to prevent recurrent infections in this population. Further research and prospective studies are warranted to validate these findings and refine interventions for optimizing patient care.

Treatment patterns in myasthenia gravis: A United States health claims analysis

INTRODUCTION/AIMS

Limited knowledge exists on treatment patterns in clinical practice in patients with myasthenia gravis (MG). In this study we examined MG treatment patterns in the United States.

METHODS

Adult patients newly diagnosed with MG were identified from the IBM MarketScan insurance claims database. Patients with ≥2 MG International Classification of Disease diagnosis codes ≥3 months apart were retrospectively followed from the date of their first MG diagnosis record or start of treatment with acetylcholinesterase inhibitors (AChEI), intravenous (IV) or subcutaneous (SC) immunoglobulin (Ig), or plasma exchange (PLEx) therapy. Based on treatment received at any time during the follow-up period, patients were segmented into six main treatment cohorts. Exacerbations and use of IVIg, SCIg, or PLEx after the index date were identified.

RESULTS

During 2010 to 2019, 7,194 patients were followed for up to 10 (median, 2.3) years. Of 6,539 treated patients, 6,462 (99%) were ever treated with AChEI and/or corticosteroids (CS); 95% were first treated with AChEI and/or CS only; 33% received ≥1 nonsteroid immunosuppressive treatment (IST) and 2% received a biologic. During treatment with first IST (n = 2,166), patients experienced 42% and 94% higher incidence rates of exacerbations and IVIg, respectively, compared with AChEI and/or CS (n = 6,242), and 33% and 23% higher, respectively, compared with a second IST (n = 353).

DISCUSSION

Many patients experienced exacerbations and received rescue therapy despite treatment, suggesting current treatments may not provide adequate disease control for some patients and that additional treatment options should be explored.

Manual therapeutic plasma exchange for treatment of a dog with suspected acute canine polyradiculoneuritis

BACKGROUND

Acute canine polyradiculoneuritis is one of the most common polyneuropathies occurring in dogs. The disease is very similar to the Guillain-Barré syndrome in humans. In veterinary medicine, there is no established treatment for this disease, while in human medicine, therapeutic plasma exchange and intravenous immunoglobulin administration are two main immunotherapy treatments of this syndrome.

CASE PRESENTATION

A 12-year-old male Jack Russel Terrier was presented with a history of acute weakness of the pelvic limbs progressing to flaccid tetraplegia with respiratory compromise. Complete diagnostic workup was performed including blood work, diagnostic imaging (radiographs of the thorax as well as ultrasound of the abdomen) and echocardiography. Based on the clinical course, neurological localisation and the results of electrodiagnostic examination acute canine polyradiculoneuritis was suspected. During the hospitalization, the dog deteriorated and was admitted to the intensive care unit for respiratory support via tracheostomy tube. In addition to symptomatic treatment, immunotherapy via single treatment of manual therapeutic plasma exchange was administered. This procedure was safe, and the dog showed improvement of clinical signs 3 days after therapy was initiated, as well as improvement of neurological signs (from grade 4 tetraplegia to grade 3) within 5 days. However, the dog was euthanized 3 weeks later due to complications related to the tracheostomy.

CONCLUSIONS

This is the first case report of a manual therapeutic plasma exchange in a dog with suspected acute canine polyradiculoneuritis suggesting that this method is safe and well tolerated in dogs with this disease. It may be a reasonable adjunctive treatment to supportive therapy in severe cases.

Risk and course of COVID-19 in immunosuppressed patients with myasthenia gravis

BACKGROUND

Patients with myasthenia gravis (MG) are potentially prone for a severe COVID-19 course, but there are limited real-world data available on the risk associated with COVID-19 for patients with MG. Here, we investigate whether current immunosuppressive therapy (IST) influences the risk of SARS-CoV-2 infection and COVID-19 severity.

METHODS

Data from the German myasthenia gravis registry were analyzed from May 2020 until June 2021 and included patient demographics, MG disease duration, comorbidities, current IST use, COVID-19 characteristics, and outcomes. Propensity score matching was employed to match MG patients with IST to those without, and multivariable binary logistic regression models were used to determine associations between IST with (1) symptomatic SARS-CoV-2 infection and (2) severe COVID-19 course, as measured by hospitalization or death.

RESULTS

Of 1379 patients with MG, 95 (7%) patients (mean age 58 (standard deviation [SD] 18) presented with COVID-19, of which 76 (80%) received IST at time of infection. 32 patients (34%) were hospitalized due to COVID-19; a total of 11 patients (12%) died. IST was a risk factor for hospitalization or death in the group of COVID-19-affected MG patients (odds ratio [OR] 3.04, 95% confidence interval [CI] = 1.02-9.06, p = 0.046), but current IST was not associated with a higher risk for SARS-CoV-2 infection itself.

DISCUSSION

In this national MG cohort study, current IST use was a risk factor for a severe disease course of COVID-19 but not for SARS-CoV-2 infection itself. These data support the consequent implementation of effective strategies to prevent COVID-19 in this high-risk group.

TRIAL REGISTRATION INFORMATION

German clinical trial registry ( https://www.drks.de ), DRKS00024099, first patient enrolled: February 4th, 2019.

Critical illness-associated weakness and related motor disorders

Weakness of limb and respiratory muscles that occurs in the course of critical illness has become an increasingly common and serious complication of adult and pediatric intensive care unit patients and a cause of prolonged ventilatory support, morbidity, and prolonged hospitalization. Two motor disorders that occur singly or together, namely critical illness polyneuropathy and critical illness myopathy, cause weakness of limb and of breathing muscles, making it difficult to be weaned from ventilatory support, commencing rehabilitation, and extending the length of stay in the intensive care unit, with higher rates of morbidity and mortality. Recovery can take weeks or months and in severe cases, and may be incomplete or absent. Recent findings suggest an improved prognosis of critical illness myopathy compared to polyneuropathy. Prevention and treatment are therefore very important. Its management requires an integrated team approach commencing with neurologic consultation, creatine kinase (CK) measurement, detailed electrodiagnostic, respiratory and neuroimaging studies, and potentially muscle biopsy to elucidate the etiopathogenesis of the weakness in the peripheral and/or central nervous system, for which there may be a variety of causes. These tenets of care are being applied to new cases and survivors of the coronavirus-2 disease pandemic of 2019. This chapter provides an update to the understanding and approach to critical illness motor disorders.

On the path to evidence-based therapy in neuromuscular disorders

Neuromuscular disorders encompass a diverse group of acquired and genetic diseases characterized by loss of motor functionality. Although cure is the goal, many therapeutic strategies have been envisioned and are being studied in randomized clinical trials and entered clinical practice. As in all scientific endeavors, the successful clinical translation depends on the quality and translatability of preclinical findings and on the predictive value and feasibility of the clinical models. This chapter focuses on five exemplary diseases: childhood spinal muscular atrophy (SMA), Charcot-Marie-Tooth (CMT) disorders, chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), acquired autoimmune myasthenia gravis (MG), and Duchenne muscular dystrophy (DMD), to illustrate the progress made on the path to evidenced-based therapy.

Total Plasma Exchange in Neuromuscular Junction Disorders—A Single-Center, Retrospective Analysis of the Efficacy, Safety and Potential Diagnostic Properties in Doubtful Diagnosis

Neuromuscular junction disorders (NJDs) are a heterogeneous group of diseases including myasthenia gravis (MG). In some cases, patients are present with myasthenic symptoms without evidence of autoimmune antibodies, making diagnosis challenging. Total plasma exchange (TPE) has proven efficacy in NJDs. The objective is to describe the safety and efficacy of TPE in NJD patients with questionable disease activity or uncertain diagnosis in order to assess the diagnostic potential of TPE. We report an observational, retrospective cohort study of clinical routine data. All the data were derived from the electronic medical records of the Department of Neurology at University Hospital Essen. We searched for patients with NJDs between 1 July 2018 and 30 June 2021. Of the 303 patients who presented to the department with NJDs, 20 were treated with TPE; 9 patients did not show a measurable benefit from TPE (45%), 6 of whom were diagnosed with seronegative MG. Of these, 3 (50%) had long-standing ocular symptoms. There were decreases in the mean arterial pressure, hemoglobin, hematocrit and fibrinogen during treatment, which were not considered clinically relevant. In (seronegative) myasthenic patients, TPE may help to verify an uncertain diagnosis or to reveal possible muscle damage, allowing unnecessary therapy to be avoided.

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

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

Prescribing Practices of Intravenous Immunoglobulin in Tertiary Care Hospitals in Malaysia: A Need for a National Guideline for Immunoglobulin Use

Rational use of drug involves the use of medicine as per clinical guidelines. Given the steady increase in the clinical utility of intravenous immunoglobulin (IVIG) either as licensed or off-label use, concerns are being raised about the possibility of supply shortages that could significantly impact patient care. Therefore, there is a need to regulate and to promote the rational use of this valuable medication. This cross-sectional chart review study attempts to evaluate the prescribing patterns of IVIG at two tertiary hospitals in Malaysia. Patients’ medical files and dispensing records were examined and compared with current guidelines. A total of 348 prescriptions for IVIG were written during the 1-year study period. The highest usage of IVIG was for neurological (47.9%), immunological (27.5%), and hematological conditions (20%). The number of prescriptions with the US Food and Drug Administration (FDA) licensed indications and off-label indications was 148 (42.5%) and 200 (57.5%), respectively. Age (OR: 1.02, 95% CI: 1.01–1.03, p = 0.003) and those admitted to the critical care units (OR: 11.11, 95% CI: 5.60–22.05, p < 0.001) were significant factors for receiving IVIG for an off-label indication. Most prescriptions (79%) had appropriate dosing. Significant factors associated with receiving inappropriate dose of IVIG include age (OR: 0.93, 95% CI: 0.89–0.97, p = 0.001) and those admitted to the critical care units (OR: 10.15, 95% CI: 3.81–27.06, p < 0.001). This study advocates the development and implementation of evidence-based clinical guidelines with prioritization protocol to ensure rational use of IVIG.

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.