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San PP, Jacob S. Role of complement in myasthenia gravis. Front Neurol 2023; 14:1277596. [PMID: 37869140 PMCID: PMC10585143 DOI: 10.3389/fneur.2023.1277596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 09/18/2023] [Indexed: 10/24/2023] Open
Abstract
Myasthenia gravis is a prototypic neuroimmune disorder with autoantibodies targeting the acetylcholine receptor complex at the neuromuscular junction. Patients present with mainly ocular muscle weakness and tend to have a generalized muscle weakness later in the clinical course. The weakness can be severe and fatal when bulbar muscles are heavily involved. Acetylcholine receptor antibodies are present in the majority of patients and are of IgG1 and IgG3 subtypes which can activate the complement system. The complement involvement plays a major role in the neuromuscular junction damage and the supporting evidence in the literature is described in this article. Complement therapies were initially studied and approved for paroxysmal nocturnal hemoglobinuria and in the past decade, those have also been studied in myasthenia gravis. The currently available randomized control trial and real-world data on the efficacy and safety of the approved and investigational complement therapies are summarized in this review.
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Affiliation(s)
- Pyae Phyo San
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, United Kingdom
| | - Saiju Jacob
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, United Kingdom
- Department of Neurology, Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
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Flammer J, Neziraj T, Rüegg S, Pröbstel AK. Immune Mechanisms in Epileptogenesis: Update on Diagnosis and Treatment of Autoimmune Epilepsy Syndromes. Drugs 2023; 83:135-158. [PMID: 36696027 PMCID: PMC9875200 DOI: 10.1007/s40265-022-01826-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/07/2022] [Indexed: 01/26/2023]
Abstract
Seizures and epilepsy can result from various aetiologies, yet the underlying cause of several epileptic syndromes remains unclear. In that regard, autoimmune-mediated pathophysiological mechanisms have been gaining attention in the past years and were included as one of the six aetiologies of seizures in the most recent classification of the International League Against Epilepsy. The increasing number of anti-neuronal antibodies identified in patients with encephalitic disorders has contributed to the establishment of an immune-mediated pathophysiology in many cases of unclear aetiology of epileptic syndromes. Yet only a small number of patients with autoimmune encephalitis develop epilepsy in the proper sense where the brain transforms into a state where it will acquire the enduring propensity to produce seizures if it is not hindered by interventions. Hence, the term autoimmune epilepsy is often wrongfully used in the context of autoimmune encephalitis since most of the seizures are acute encephalitis-associated and will abate as soon as the encephalitis is in remission. Given the overlapping clinical presentation of immune-mediated seizures originating from different aetiologies, a clear distinction among the aetiological entities is crucial when it comes to discussing pathophysiological mechanisms, therapeutic options, and long-term prognosis of patients. Moreover, a rapid and accurate identification of patients with immune-mediated epilepsy syndromes is required to ensure an early targeted treatment and, thereby, improve clinical outcome. In this article, we review our current understanding of pathogenesis and critically discuss current and potential novel treatment options for seizures and epilepsy syndromes of underlying or suspected immune-mediated origin. We further outline the challenges in proper terminology.
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Affiliation(s)
- Julia Flammer
- Department of Neurology, University Hospital Basel and University of Basel, Petersgraben 4, 4031, Basel, Switzerland.,Departments of Biomedicine and Clinical Research, University Hospital Basel and University of Basel, Basel, Switzerland.,Research Center for Clinical Neuroimmunology and Neuroscience Basel (RC2NB), University Hospital Basel and University of Basel, Basel, Switzerland
| | - Tradite Neziraj
- Department of Neurology, University Hospital Basel and University of Basel, Petersgraben 4, 4031, Basel, Switzerland.,Departments of Biomedicine and Clinical Research, University Hospital Basel and University of Basel, Basel, Switzerland.,Research Center for Clinical Neuroimmunology and Neuroscience Basel (RC2NB), University Hospital Basel and University of Basel, Basel, Switzerland
| | - Stephan Rüegg
- Department of Neurology, University Hospital Basel and University of Basel, Petersgraben 4, 4031, Basel, Switzerland.
| | - Anne-Katrin Pröbstel
- Department of Neurology, University Hospital Basel and University of Basel, Petersgraben 4, 4031, Basel, Switzerland. .,Departments of Biomedicine and Clinical Research, University Hospital Basel and University of Basel, Basel, Switzerland. .,Research Center for Clinical Neuroimmunology and Neuroscience Basel (RC2NB), University Hospital Basel and University of Basel, Basel, Switzerland.
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Waheed W, Newman E, Aboukhatwa M, Moin M, Tandan R. Practical Management for Use of Eculizumab in the Treatment of Severe, Refractory, Non-Thymomatous, AChR + Generalized Myasthenia Gravis: A Systematic Review. Ther Clin Risk Manag 2022; 18:699-719. [PMID: 35855752 PMCID: PMC9288180 DOI: 10.2147/tcrm.s266031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Accepted: 07/04/2022] [Indexed: 11/28/2022] Open
Abstract
Myasthenia gravis (MG) is a rare autoimmune disorder caused by specific autoantibodies at the neuromuscular junction. MG is classified by the antigen specificity of these antibodies. Acetylcholine receptor (AChR) antibodies are the most common type (74–88%), followed by anti-muscle specific kinase (MuSK) and other antibodies. While all these antibodies lead to neuromuscular transmission failure, the immuno-pathogenic mechanisms are distinct. Complement activation is a primary driver of AChR antibody-positive MG (AChR+ MG) pathogenesis. This leads to the formation of the membrane attack complex and destruction of AChR receptors and the postsynaptic membrane resulting in impaired neurotransmission and muscle weakness characteristic of MG. Broad-based immune-suppressants like corticosteroids are effective in controlling MG; however, their long-term use can be associated with significant adverse effects. Advances in translational research have led to the development of more directed therapeutic agents that are likely to alter the future of MG treatment. Eculizumab is a humanized monoclonal antibody that inhibits the cleavage of complement protein C5 and is approved for use in generalized MG. In this review, we discuss the pathophysiology of MG; the therapeutic efficacy and tolerability of eculizumab, as well as the practical guidelines for its use in MG; future studies exploring the role of eculizumab in different stages and subtypes of MG subtypes; the optimal duration of therapy and its discontinuation; the characterization of non-responder patients; and the use of biomarkers for monitoring therapy are highlighted. Based on the pathophysiologic mechanisms, emerging therapies and new therapeutic targets are also reviewed.
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Affiliation(s)
- Waqar Waheed
- Department of Neurological Sciences, The University of Vermont and the University of Vermont Medical Center, Burlington, VT, USA
| | - Eric Newman
- Department of Neurological Sciences, The University of Vermont and the University of Vermont Medical Center, Burlington, VT, USA
| | - Marwa Aboukhatwa
- Pharmacotherapy Department, University of Vermont Medical Center, Burlington, VT, USA
| | - Maryam Moin
- Department of Neurology, University of Illinois College of Medicine, Peoria, IL, USA
| | - Rup Tandan
- Department of Neurological Sciences, The University of Vermont and the University of Vermont Medical Center, Burlington, VT, USA
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Suh J, Clarke V, Amato AA, Guidon AC. Safety and outcomes of eculizumab for acetylcholine receptor-positive generalized myasthenia gravis in clinical practice. Muscle Nerve 2022; 66:348-353. [PMID: 35684980 DOI: 10.1002/mus.27656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 06/02/2022] [Accepted: 06/03/2022] [Indexed: 11/06/2022]
Abstract
INTRODUCTION/AIMS Safety and outcomes data on eculizumab for generalized myasthenia gravis (gMG) in clinical practice remain limited. Outcomes and concomitant medication use may differ in practice compared with clinical trials. We analyzed the clinical and safety outcomes of patients who received eculizumab at our institutions. METHODS Patients with acetylcholine receptor antibody positive (AChR+) gMG, who received ≥1 dose of eculizumab and had ≥1 follow-up before December 10, 2021, were identified. Data were abstracted by chart review. Outcomes included MG Foundation of America Post Intervention Status (MGFA-PIS), Clinical Classification (MGFA-CC), MG-Activities of Daily Living (MG-ADL), concurrent immunomodulatory therapy use, and adverse events. RESULTS Twelve patients were included. Mean age at eculizumab initiation was 57.4 y (range, 21-77). Eight had refractory MG. Four had history of thymoma and thymectomy. A mean of 3.2 (range, 2-5) immunomodulatory therapies were previously tried. Mean follow-up duration was 18 mo (range, 2-21.6). Clinical improvement occurred rapidly; MGFA-PIS was improved in 80%, and MGFA-CC improved in 83% at 1 mo. Mean MG-ADL decreased from 8.7 to 2.8 at 1 mo, and remained ≤ 3 $$ \le 3 $$ .5 over 1.5 y. Mean daily prednisone dose decreased from 22.5 mg to 7.2 mg at 1.5 y. Five of 7 patients discontinued maintenance IVIG or PLEX. No patients had meningococcal infections and adverse events were mild. DISCUSSION Clinical improvement occurred in most patients after eculizumab initiation, beginning as quickly as 1 mo. Steroids were tapered and maintenance IVIG and PLEX were discontinued in most. Eculizumab had a favorable safety profile even when combined with other immunosuppressants.
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Affiliation(s)
- Joome Suh
- Division of Neuromuscular Medicine, Department of Neurology, Brigham and Women's Hospital, Boston, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA
| | - Virginia Clarke
- Division of Neuromuscular Medicine, Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Anthony A Amato
- Division of Neuromuscular Medicine, Department of Neurology, Brigham and Women's Hospital, Boston, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA
| | - Amanda C Guidon
- Harvard Medical School, Boston, Massachusetts, USA.,Division of Neuromuscular Medicine, Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, USA
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Binu A, Kumar SS, Padma UD, Madhu K. Pathophysiological basis in the management of myasthenia gravis: a mini review. Inflammopharmacology 2022; 30:61-71. [DOI: 10.1007/s10787-021-00905-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 11/30/2021] [Indexed: 11/05/2022]
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Jiao L, Li H, Guo S. Eculizumab treatment for myasthenia gravis subgroups: 2021 update. J Neuroimmunol 2022; 362:577767. [PMID: 34823117 DOI: 10.1016/j.jneuroim.2021.577767] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 11/01/2021] [Accepted: 11/13/2021] [Indexed: 01/21/2023]
Abstract
Eculizumab is a recombinant humanized monoclonal antibody that targets the complement protein C5, inhibiting its cleavage into C5a and C5b and ultimately preventing the formation of C5b-9 membrane attack complex (MACs), thereby protecting the neuromuscular junction from the damage of complement activation. In 2017, eculizumab became the second FDA-approved medication for AchR-positive generalized myasthenia gravis (gMG) patients based on the successful results of a randomized, double-blinded, placebo-controlled, phase 2, phase 3 study (the REGAIN trial) and its open-label extension study. Despite the efficacy of eculizumab in treating AchR antibody-positive refractory gMG was demonstrated in the REGAIN study, there is few information on its efficacy in other subgroup of MG patients including seronegative MG, thymoma-associated MG and MG crisis. This narrative review summarizes current clinical studies of eculizumab in these refractory gMG patients, with a focus on the therapeutic efficacy and tolerability in different subgroup of MG.
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Affiliation(s)
- Li Jiao
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jing Wu Road, Huaiyin District, Jinan 250021, Shandong, China
| | - Honghao Li
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jing Wu Road, Huaiyin District, Jinan 250021, Shandong, China
| | - Shougang Guo
- Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jing Wu Road, Huaiyin District, Jinan 250021, Shandong, China.
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Muppidi S, Silvestri NJ, Tan R, Riggs K, Leighton T, Phillips GA. Utilization of MG-ADL in myasthenia gravis clinical research and care. Muscle Nerve 2022; 65:630-639. [PMID: 34989427 PMCID: PMC9302997 DOI: 10.1002/mus.27476] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 12/15/2021] [Accepted: 12/15/2021] [Indexed: 11/17/2022]
Abstract
The Myasthenia Gravis Activities of Living (MG‐ADL) scale is an 8‐item patient‐reported scale that measures myasthenia gravis (MG) symptoms and functional status. The objective of the current review is to summarize the psychometric properties of the MG‐ADL and published evidence of MG‐ADL use. A targeted literature review for published studies of the MG‐ADL was conducted using a database and gray literature search. A total of 48 publications and 35 clinical trials were included. Studies indicated that the MG‐ADL is a reliable and valid measure that has been used as an outcome in clinical trials and observational studies to measure MG symptoms and response to treatment. While most often used as a secondary endpoint in clinical trials, its use as a primary endpoint has increased in recent years. The most common MG‐ADL endpoint is change in MG‐ADL score from baseline, although there has been an increase in the analysis of a responder threshold using the MG‐ADL. A new concept of minimal symptom expression (MSE) has emerged more recently. Duration of treatment effect is another important construct that is being increasingly evaluated using the MG‐ADL. The use of the MG‐ADL as a primary endpoint in clinical trials and in responder threshold analyses to indicate treatment improvement has increased in recent years. MSE using the MG‐ADL shows promise in helping to determine success of treatment and may be the aspirational goal of MG treatment for the future once validated, particularly given the evolving treatment landscape in MG.
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Affiliation(s)
- Srikanth Muppidi
- Neurology & Neurological Sciences, Stanford University School of Medicine, Stanford, California, USA
| | - Nicholas J Silvestri
- Department of Neurology, State University of New York, Buffalo Jacobs School of Medicine and Biomedical Sciences, Buffalo, New York, USA
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Johnson S, Katyal N, Narula N, Govindarajan R. Adverse Side Effects Associated with Corticosteroid Therapy: A Study in 39 Patients with Generalized Myasthenia Gravis. Med Sci Monit 2021; 27:e933296. [PMID: 34707081 PMCID: PMC8562011 DOI: 10.12659/msm.933296] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Background The tolerability of high-dose oral corticosteroids in patients with generalized myasthenia gravis (gMG) has not been systematically assessed. We evaluated adverse side effects (ASEs) of corticosteroid treatment in patients with gMG. Material/Methods Retrospective analysis was conducted of ASEs reported as being related to corticosteroid treatment in 39 patients with gMG who were treated with oral corticosteroids for ≥1 year. Results Median (interquartile range [IQR]) age was 60 (21) years, 53.8% of patients were women, and 66.7% were aged ≤65 years. Median (IQR) prednisone treatment duration was 14 (2) months; median (IQR) daily dose was 40 (15) mg. The median number of ASEs reported as corticosteroid-related was 2/patient (IQR, 1). Pre-diabetes and weight gain were most common (each 43.6% of patients). Bruising, insomnia, and osteoporosis were more prevalent in patients aged >65 years, while irritability, osteopenia, and pre-diabetes were more common in patients aged ≤65 years, although differences were not statistically significant. Irritability and weight gain were more prevalent in women (P=0.010 for irritability); osteoporosis and pre-diabetes more common in men (P=0.015 for osteoporosis). ASEs were generally more common in the high-dose prednisone group (>30 mg/day), but were only statistically significant for irritability (P=0.001). Conclusions Corticosteroid-related ASEs were common in patients with gMG. Some of these ASEs can have serious medical consequences, and certain ASEs appeared to be associated with specific patient characteristics. Demographics and comorbidities of patients with gMG must be carefully considered before corticosteroid initiation. Potential ASEs, such as unanticipated osteoporosis in men, require extra vigilance.
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Affiliation(s)
- Stephen Johnson
- Department of Neurology, Brigham and Women's Hospital and Massachusetts General Hospital, Boston, MA, USA
| | - Nakul Katyal
- Department of Neurology, University of Missouri Health Care, Columbia, MO, USA
| | - Naureen Narula
- Department of Pulmonary and Critical Care, Northwell Health - Staten Island University Hospital, New York City, NY, USA
| | - Raghav Govindarajan
- Department of Neurology, University of Missouri Health Care, Columbia, MO, USA
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Xiao H, Wu K, Liang X, Li R, Lai KP. Clinical Efficacy and Safety of Eculizumab for Treating Myasthenia Gravis. Front Immunol 2021; 12:715036. [PMID: 34456922 PMCID: PMC8384962 DOI: 10.3389/fimmu.2021.715036] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 07/26/2021] [Indexed: 12/18/2022] Open
Abstract
Myasthenia gravis (MG) is an autoimmune disease primarily mediated by acetylcholine receptor antibodies (AChR-Ab), cellular immune dependence, and complement system involvement. Since the AChR on the postsynaptic membrane is destroyed by an immune attack, sufficient endplate potential cannot be generated, resulting in the development of a synaptic transmission disorder at the neuromuscular junction and in muscle weakness. The role of the complement system in MG has been demonstrated in animal models and clinical tests, and it has been determined that complement inhibition in patients with MG can prevent disease induction and reverse its progression. Eculizumab is a humanized monoclonal antibody that inhibits the cleavage of complement protein C5 and prevents autoimmune damage; additionally, it has received subsequent approval by the Federal Drug Administration of the United States for MG treatment. However, various concerns regarding the use of eculizumab persist. In this review, we have discussed the treatment time, cost effectiveness, long-term efficacy, and tolerability of eculizumab for MG treatment. We have also summarized historical information and have presented perspectives on this new therapeutic modality.
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Affiliation(s)
- Hai Xiao
- Department of Neurology, Guigang City People's Hospital, The Eighth Affiliated Hospital of Guangxi Medical University, Guigang, China
| | - Ka Wu
- Department of Pharmacy, The Second People's Hospital of Nanning City, The Third Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Xiaoliu Liang
- College of Pharmacy, Guangxi Medical University, Nanning, China
| | - Rong Li
- Laboratory of Environmental Pollution and Integrative Omics, Guilin Medical University, Guilin, China
| | - Keng Po Lai
- Laboratory of Environmental Pollution and Integrative Omics, Guilin Medical University, Guilin, China
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