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Mantegazza R, Saccà F, Antonini G, Bonifati DM, Evoli A, Habetswallner F, Liguori R, Pegoraro E, Rodolico C, Schenone A, Sgarzi M, Pappagallo G. Therapeutic challenges and unmet needs in the management of myasthenia gravis: an Italian expert opinion. Neurol Sci 2024:10.1007/s10072-024-07577-7. [PMID: 38967883 DOI: 10.1007/s10072-024-07577-7] [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: 12/27/2023] [Accepted: 05/03/2024] [Indexed: 07/06/2024]
Abstract
Myasthenia gravis (MG) is a rare, autoimmune, neurological disorder. Most MG patients have autoantibodies against acetylcholine receptors (AChRs). Some have autoantibodies against muscle-specific tyrosine kinase (MuSK) or lipoprotein-receptor-related protein 4 (LRP4), and some are seronegative. Standard of care, which includes anti-cholinesterase drugs, thymectomy, corticosteroids (CS), and off-label use of non-steroidal immunosuppressive drugs (NSISTs), is bounded by potential side effects and limited efficacy in refractory generalized MG (gMG) patients. This highlights the need for new therapeutic approaches for MG. Eculizumab, a monoclonal antibody that inhibits the complement system, has been recently approved in Italy for refractory gMG. A panel of 11 experts met to discuss unmet therapeutic needs in the acute and chronic phases of the disease, as well as the standard of care for refractory patients. Survival was emphasized as an acute phase outcome. In the chronic phase, persistent remission and early recognition of exacerbations to prevent myasthenic crisis and respiratory failure were considered crucial. Refractory patients require treatments with fast onset of action, improved tolerability, and the ability to slow disease progression and increase life expectancy. The Panel agreed that eculizumab would presumably meet the therapeutic needs of many refractory gMG patients. The panel concluded that the unmet needs of current standard of care treatments for gMG are significant. Evaluating new therapeutic options accurately is essential to find the best balance between efficacy and tolerability for each patient. Collecting real-world data on novel molecules in routine clinical practice is necessary to address unmet needs.
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Affiliation(s)
- Renato Mantegazza
- Neuroimmunology and Neuromuscular Diseases Unit, IRCCS Foundation Carlo Besta Neurological Institute, Milan, Italy.
| | - Francesco Saccà
- NSRO Department, Federico II University of Naples, Naples, Italy
| | - Giovanni Antonini
- Department of Neurosciences, Mental Health and Sensory Organs (NESMOS), Sapienza University of Rome, Rome, Italy
| | - Domenico Marco Bonifati
- Neurology Unit, Cerebro-Cardiovascular Department, Ca' Foncello Hospital Treviso, Piazzale Ospedale 1, 31100, Treviso, Italy
| | - Amelia Evoli
- Neuroscience Department, Facolta Di Medicina E Chirurgia, Università Cattolica del Sacro Cuore, Rome, Italy
- Neurology Institute, Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Rome, Italy
| | | | - Rocco Liguori
- Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
- IRCCS Istituto Delle Scienze Neurologiche Di Bologna, UOC Clinica Neurologica, Bologna, Italy
| | | | - Carmelo Rodolico
- Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Angelo Schenone
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetic and Maternal and Infantile Sciences (DINOGMI), University and IRCCS San Martino Hospital, Genoa, Italy
| | - Manlio Sgarzi
- Department of Neurology, Papa Giovanni XXIII Hospital, Piazza OMS 1, 24127, Bergamo, Italy
| | - Giovanni Pappagallo
- School of Clinical Methodology, IRCCS "Sacred Heart - Don Calabria", Negrar Di Valpolicella, Italy
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Chan F, Hardy TA, Malik S, Ramanathan S, Riminton DS, Reddel SW. Induction cyclophosphamide with maintenance immunosuppression in high-risk myasthenia gravis: long-term follow-up and safety profile. J Neurol Neurosurg Psychiatry 2024:jnnp-2023-333189. [PMID: 38964847 DOI: 10.1136/jnnp-2023-333189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 04/10/2024] [Indexed: 07/06/2024]
Abstract
BACKGROUND Patients with refractory or high-risk myasthenia gravis (MG) respond poorly to conventional immunosuppressive therapy, requiring rescue therapies and often experiencing treatment toxicity. Rescue and injectable therapies do not induce remission and require repetitive administration leading to significant constraints on patients and the healthcare system. This long-term follow-up study demonstrates cyclophosphamide as a rapidly effective and safe treatment in patients with refractory or high-risk MG. METHODS Retrospective cohort study of MG patients treated with cyclophosphamide between January 2000 and June 2022 conducted at a quaternary neuroimmunology clinic in New South Wales, Australia. RESULTS 31 patients were treated: mean age of 64 years; median follow-up 3.6 years (5 months to 11 years); 94% seropositive to acetylcholine receptor (AChR) antibodies and 45% had thymoma. A reduced intensity cyclophosphamide induction protocol followed by oral antiproliferative maintenance is described.Median myasthenia gravis composite scores reduced by >50% after the third cycle of cyclophosphamide. Complete cessation of prednisolone was possible in 11 patients while 20 remained on prednisolone with a median daily dose of 5 mg. Plasma exchange was ceased in 62% of patients and intravenous immunoglobulin ceased in 55%. Cyclophosphamide was generally well tolerated with mild cytopenias. There were no malignancies or cases of haemorrhagic cystitis. CONCLUSION We describe a large cohort of high-risk MG patients treated with cyclophosphamide in a retrospective single-clinic cohort. We suggest cyclophosphamide should be considered for rapid remission induction, corticosteroid reduction and long-term freedom from recurrent injectable therapies in selected patients, typically those with AChR antibodies.
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Affiliation(s)
- Fiona Chan
- Queen Elizabeth Hospital, Birmingham, UK
| | - Todd A Hardy
- Department of Neurology, Concord Hospital, Concord, New South Wales, Australia
| | - Sameer Malik
- Department of Immunology, Concord Hospital, Concord, New South Wales, Australia
| | - Sudarshini Ramanathan
- Department of Neurology, Concord Hospital, Concord, New South Wales, Australia
- University of Sydney, Sydney, New South Wales, Australia
| | - D Sean Riminton
- Department of Immunology, Concord Hospital, Concord, New South Wales, Australia
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Hehir MK, Li Y. Diagnosis and Management of Myasthenia Gravis. Continuum (Minneap Minn) 2022; 28:1615-1642. [PMID: 36537972 DOI: 10.1212/con.0000000000001161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
PURPOSE OF REVIEW This article reviews updated diagnostic procedures and currently available treatment modalities for myasthenia gravis (MG). RECENT FINDINGS Patients with MG can be classified based on antibody status and their clinical presentation; treatment responses may differ based on disease subtypes. Improved diagnostic methods and recognition of new antigenic targets such as lipoprotein-related protein 4 have led to improved diagnostic efficiencies. Corticosteroids remain the first-line immunotherapy, but there is a trend toward minimizing their use at high doses and for long durations. Oral immunosuppressants such as mycophenolate mofetil, azathioprine, and tacrolimus remain useful. An international, multicenter randomized trial comparing thymectomy plus prednisone with prednisone alone demonstrated that thymectomy improves clinical outcomes in selected patients with nonthymomatous MG. Eculizumab, efgartigimod, and ravulizumab have recently been approved by the US Food and Drug Administration (FDA) for adult patients with generalized MG who are acetylcholine receptor-antibody positive. These drugs take advantage of novel mechanisms of action and expand treatment options for patients with MG. Data on rituximab suggest that it can be a good option, especially for patients with MG who are positive for antibodies against muscle-specific tyrosine kinase (MuSK). The number of clinical trials and drugs in development for MG is steadily increasing. SUMMARY The diagnosis of MG can generally be made from the patient's history, a neurologic examination, and laboratory and electrodiagnostic testing. Carefully selected treatment improves outcomes in MG. Additional treatment options for MG will likely be available in the near future.
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Menon D, Bril V. Pharmacotherapy of Generalized Myasthenia Gravis with Special Emphasis on Newer Biologicals. Drugs 2022; 82:865-887. [PMID: 35639288 PMCID: PMC9152838 DOI: 10.1007/s40265-022-01726-y] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/25/2022] [Indexed: 11/20/2022]
Abstract
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.
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Affiliation(s)
- Deepak Menon
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Vera Bril
- Ellen and Martin Prosserman Centre for Neuromuscular Diseases, University Health Network, 5EC-309, Toronto General Hospital, University of Toronto, 200 Elizabeth St, Toronto, M5G 2C4, Canada.
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Alhaidar MK, Abumurad S, Soliven B, Rezania K. Current Treatment of Myasthenia Gravis. J Clin Med 2022; 11:jcm11061597. [PMID: 35329925 PMCID: PMC8950430 DOI: 10.3390/jcm11061597] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 03/09/2022] [Accepted: 03/10/2022] [Indexed: 02/04/2023] Open
Abstract
Myasthenia gravis (MG) is the most extensively studied antibody-mediated disease in humans. Substantial progress has been made in the treatment of MG in the last century, resulting in a change of its natural course from a disease with poor prognosis with a high mortality rate in the early 20th century to a treatable condition with a large proportion of patients attaining very good disease control. This review summarizes the current treatment options for MG, including non-immunosuppressive and immunosuppressive treatments, as well as thymectomy and targeted immunomodulatory drugs.
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Jeong S, Noh Y, Oh IS, Hong YH, Shin JY. Survival, Prognosis, and Clinical Feature of Refractory Myasthenia Gravis: a 15-year Nationwide Cohort Study. J Korean Med Sci 2021; 36:e242. [PMID: 34636500 PMCID: PMC8506414 DOI: 10.3346/jkms.2021.36.e242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 08/11/2021] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Myasthenia gravis (MG) is a rare classic autoimmune disease where immunosuppressant therapies have been successful to reduce MG attributable mortality fairly well. However, patients with refractory MG (rMG) among the actively treated MG (aMG) are nonresponsive to conventional therapy and display high disease severity, which calls for further research. We aimed to determine survival, prognosis, and clinical feature of patients with rMG compared to non-rMG. METHODS Retrospective nationwide cohort study using Korea's healthcare database between 2002 and 2017 was conducted. Patients with rMG (n = 47) and non-rMG (n = 4,251) who were aged > 18 years, followed-up for ≥ 1 year, and prescribed immunosuppressants within 2 years after incident MG diagnosis were included. Patients with rMG were defined as administered plasma exchange or intravenous immunoglobulin at least 3 times per year after receiving ≥ 2 immunosuppressants. All-cause mortality, myasthenic crisis, hospitalization, pneumonia/sepsis, and emergency department (ED) visits were measured using Cox proportional hazard models and pharmacotherapy patterns for rMG were assessed. RESULTS The rMG cohort included a preponderance of younger patients and women. The adjusted hazard ratio was 2.49 (95% confidence interval, 1.26-4.94) for mortality, 3.14 (2.25-4.38) for myasthenic crisis, 1.54 (1.15-2.06) for hospitalization, 2.69 (1.74-4.15) for pneumonia/sepsis, and 1.81 (1.28-2.56) for ED visits for rMG versus non-rMG. The immunosuppressant prescriptions were more prevalent in patients with rMG, while the difference was more remarkable before rMG onset rather than after rMG onset. CONCLUSION Despite the severe prognosis of rMG, the strategies for pharmacotherapeutic regimens were similar in those two groups, suggesting that intensive monitoring and introduction of timely treatment options in the early phase of MG are required.
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Affiliation(s)
- Sohyun Jeong
- Department of Pharmacy, School of Pharmacy, Sungkyunkwan University, Suwon, Korea
- Marcus Institute for Aging Research, Hebrew SeniorLife and Harvard Medical School, Boston, MA, USA
| | - Yunha Noh
- Department of Pharmacy, School of Pharmacy, Sungkyunkwan University, Suwon, Korea
| | - In-Sun Oh
- Department of Pharmacy, School of Pharmacy, Sungkyunkwan University, Suwon, Korea
| | - Yoon-Ho Hong
- Department of Neurology, Neuroscience Research Institute, Seoul National University Medical Research Council, Seoul Metropolitan Boramae Medical Center, Seoul National University College of Medicine, Seoul, Korea
| | - Ju-Young Shin
- Department of Pharmacy, School of Pharmacy, Sungkyunkwan University, Suwon, Korea
- Department of Clinical Research Design & Evaluation, SAIHST, Sungkyunkwan University, Seoul, Korea.
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Fatehi F, Moradi K, Okhovat AA, Shojatalab G, Sedighi B, Boostani R, Sarraf P, Haghi Ashtiani B, Ghasemi M, Moussavi S, Anjidani N, Nafissi S. Zytux in Refractory Myasthenia Gravis: A Multicenter, Open-Labeled, Clinical Trial Study of Effectiveness and Safety of a Rituximab Biosimilar. Front Neurol 2021; 12:682622. [PMID: 34512504 PMCID: PMC8427762 DOI: 10.3389/fneur.2021.682622] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 07/09/2021] [Indexed: 01/10/2023] Open
Abstract
Objectives: Myasthenia gravis (MG) is an immune-mediated neuromuscular disorder responsive to immunomodulatory treatments. 10-20% of MGs are not responsive to conventional first-line therapies. Here, we sought to investigate the efficacy and safety of rituximab therapy in the treatment of patients with refractory MG. Methods: In a 48-week, multicenter, open-labeled, prospective cohort setting, 34 participants with refractory MG were assigned to receive infusions of Zytux, which is a rituximab biosimilar, according to a validated protocol. Clinical, functional, and quality of life (QoL) measurements were recorded at baseline, and seven further visits using the Myasthenia Gravis Foundation of America (MGFA), Myasthenia Gravis Composite (MGC), Myasthenia Gravis Activities of Daily Living profile (MG-ADL), and Myasthenia Gravis Quality of Life (MGQoL-15) scales. Besides, the post-infusion side effects were systematically assessed throughout the study. Results: The correlation analysis performed by generalized estimating equations analysis represented a significant reduction of MGC, MG-ADL, and MGQoL-15 scores across the trial period. The subgroup analysis based on the patients' clinical status indicated a significant effect for the interaction between time and MGFA subtypes on MG-ADL score, MGC score, and pyridostigmine prednisolone dose, reflecting that the worse clinical condition was associated with a better response to rituximab. Finally, no serious adverse event was documented. Conclusions: Rituximab therapy could improve clinical, functional, and QoL in patients with refractory MG in a safe setting. Further investigations with larger sample size and a more extended follow-up period are warranted to confirm this finding. Clinical Trial Registration: The study was registered by the Iranian Registry of Clinical Trials (IRCT) (Code No: IRCT20150303021315N18).
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Affiliation(s)
- Farzad Fatehi
- Neurology Department, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Kamyar Moradi
- Neurology Department, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Ali Asghar Okhovat
- Neurology Department, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran.,Neurology Department, Sina Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Ghazaleh Shojatalab
- Neurology Department, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Behnaz Sedighi
- Neurology Department, Shafa Hospital, Kerman University of Medical Sciences, Kerman, Iran
| | - Reza Boostani
- Neurology Department, Ghaem Hospital, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Payam Sarraf
- Neurology Department, Imam-Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran.,Iranian Center of Neurological Research, Tehran University of Medical Sciences, Tehran, Iran
| | - Bahram Haghi Ashtiani
- Department of Neurology, Firoozgar Hospital, Iran University of Medical Sciences, Tehran, Iran
| | - Majid Ghasemi
- Department of Neurology, Kashani Hospital, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Soussan Moussavi
- Medical Student, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Nassim Anjidani
- Head of Medical Department, Orchid Pharmed Company, Tehran, Iran
| | - Shahriar Nafissi
- Neurology Department, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
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Sheckley H, Malhotra K, Katyal N, Narula N, Govindarajan R. Clinical experience with maintenance therapeutic plasma exchange in refractory generalized myasthenia gravis. J Clin Apher 2021; 36:727-736. [PMID: 34241920 DOI: 10.1002/jca.21923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 06/22/2021] [Accepted: 06/29/2021] [Indexed: 11/07/2022]
Abstract
BACKGROUND Despite the availability of several immunomodulatory therapies, about 20% of myasthenia gravis (MG) patients remain refractory to conventional treatments. There is limited evidence to support the use of maintenance therapeutic plasma exchange (TPE) therapy for refractory generalized MG. METHODS Retrospective chart review of 14 patients with refractory generalized MG treated for 12 months with maintenance TPE therapy. Outcome measures were myasthenia gravis composite (MGC) score, myasthenia gravis activities of daily living (MG-ADL), number of acute exacerbations, medication changes, and adverse events. Data were collected at 3 monthly intervals for 12 months before and after initiation of TPE therapy. RESULTS Clinically meaningful reductions in mean MG-ADL (>2 points) (mean MG-ADL score: 9.9 ± 0.5; 12-month pre-TPE to 5.2 ± 0.9; 12-month post-TPE) and MGC (>3 points) (mean MGC score: 25.2 ± 1.6; 12-month pre-TPE to 11.7 ± 1.4; 12-month post-TPE) were observed at 3 months following initiation of TPE and were maintained up to 12 months in all patients. After 12 months of TPE therapy, all patients had a significant reduction in daily prednisone and pyridostigmine use. Patients previously on IVIG or rituximab therapy were successfully weaned off both treatments. There was a significant reduction in acute MG exacerbations; 7.8 ± 1.1 mean exacerbations/patient (12-month pre-TPE) to 2 ± 1.1 mean exacerbations/patient (12-month post-TPE). CONCLUSION Over a period of 12 months, maintenance TPE therapy improved MG-ADL, and MGC with decreased immunosuppressant requirement, while being well-tolerated.
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Affiliation(s)
- Hunter Sheckley
- Department of Neurology, University of Missouri, Columbia, Missouri, USA
| | - Kunal Malhotra
- Division of Nephrology, Department of Internal Medicine, University of Missouri, Columbia, Missouri, USA
| | - Nakul Katyal
- Department of Neurology, University of Missouri, Columbia, Missouri, USA
| | - Naureen Narula
- Department of Pulmonology and Critical Care Medicine, Staten Island University Hospital, Staten Island, New York, USA
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Wakhlu A, Manoj M, Sahoo R, Hazarika K, Bafna P. Myasthenia overlap – Report of two cases and review of literature. INDIAN JOURNAL OF RHEUMATOLOGY 2021. [DOI: 10.4103/injr.injr_305_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Update in immunosuppressive therapy of myasthenia gravis. Autoimmun Rev 2020; 20:102712. [PMID: 33197578 DOI: 10.1016/j.autrev.2020.102712] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Accepted: 07/19/2020] [Indexed: 11/22/2022]
Abstract
Myasthenia gravis (MG) is an autoimmune disease of the neuromuscular junction. Immunosuppressive treatments are part of the therapeutic armamentarium in MG. Long-term systemic steroid administration carry considerable risks and adverse events. Consequently, steroid-free immunosuppressive therapy is necessary to reduce the dose or discontinue steroids. First immunosuppressive drug trials in MG were performed in the mid-60s using standard and nonspecific immunosuppression. Since then, only few randomized controlled clinical trials were conducted in MG and assesed drug efficacy in terms of its steroid-sparing capacity and the ability to reduce myasthenic signs and symptoms. Treatment strategy in MG is quite challenging, mainly due to the disease heterogeneity in terms of clinical presentation, immunopathogenesis and drug response. To solve this dilemma, emerging treatment are based on biological drugs and use new targets of the immune pathway.
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Mantegazza R, O'Brien FL, Yountz M, Howard JF. Consistent improvement with eculizumab across muscle groups in myasthenia gravis. Ann Clin Transl Neurol 2020; 7:1327-1339. [PMID: 32700461 PMCID: PMC7448154 DOI: 10.1002/acn3.51121] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 06/10/2020] [Accepted: 06/10/2020] [Indexed: 11/30/2022] Open
Abstract
OBJECTIVE To assess whether eculizumab, a terminal complement inhibitor, improves patient- and physician-reported outcomes (evaluated using the myasthenia gravis activities of daily living profile and the quantitative myasthenia gravis scale, respectively) in patients with refractory anti-acetylcholine receptor antibody-positive generalized myasthenia gravis across four domains, representing ocular, bulbar, respiratory, and limb/gross motor muscle groups. METHODS Patients with refractory anti-acetylcholine receptor antibody-positive generalized myasthenia gravis were randomized 1:1 to receive either placebo or eculizumab during the REGAIN study (NCT01997229). Patients who completed REGAIN were eligible to continue into the open-label extension trial (NCT02301624) for up to 4 years. The four domain scores of each of the myasthenia gravis activities of daily living profile and the quantitative myasthenia gravis scale recorded throughout REGAIN and through 130 weeks of the open-label extension were analyzed. RESULTS Of the 125 patients who participated in REGAIN, 117 enrolled in the open-label extension; 61 had received placebo and 56 had received eculizumab during REGAIN. Patients experienced rapid improvements in total scores and all four domain scores of both the myasthenia gravis activities of daily living profile and the quantitative myasthenia gravis scale with eculizumab treatment. These improvements were sustained through 130 weeks of the open-label extension. INTERPRETATION Eculizumab treatment elicits rapid and sustained improvements in muscle strength across ocular, bulbar, respiratory, and limb/gross motor muscle groups and in associated daily activities in patients with refractory anti-acetylcholine receptor antibody-positive generalized myasthenia gravis.
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Affiliation(s)
- Renato Mantegazza
- Neuroimmunology and Neuromuscular Diseases UnitFondazione IRCCS Istituto Neurologico Carlo BestaMilanItaly
| | | | | | - James F. Howard
- Department of NeurologyUniversity of North CarolinaChapel HillNC
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O'Connell K, Ramdas S, Palace J. Management of Juvenile Myasthenia Gravis. Front Neurol 2020; 11:743. [PMID: 32793107 PMCID: PMC7393473 DOI: 10.3389/fneur.2020.00743] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 06/16/2020] [Indexed: 02/06/2023] Open
Abstract
Juvenile Myasthenia Gravis (JMG) is a rare disorder, defined as myasthenia gravis in children younger than 18 years of age. While clinical phenotypes are similar to adults, there are a number of caveats that influence management: broader differential diagnoses; higher rates of spontaneous remission; and the need to initiate appropriate treatment early, to avoid the long-term physical and psychosocial morbidity. Current practice is taken from treatment guidelines for adult MG or individual experience, with considerable variability seen across centers. We discuss our approach to treating JMG, in a large specialist JMG service, and review currently available evidence and highlight potential areas for future research. First-line treatment of generalized JMG is symptomatic management with pyridostigmine, but early use of immunosuppression, where good control is not achieved is important. Oral prednisolone is used as first-line immunosuppression with appropriate prevention and monitoring of side effects. Second-line therapies including azathioprine and mycophenolate may be considered where there is: no response to steroids, inability to wean to a reasonable minimum effective dose or if side-effects are intolerable. Management of ocular JMG is similar, but requires close involvement of ophthalmology in young children to prevent amblyopia. Muscle-specific tyrosine kinase (MuSK)-JMG show a poorer response to pyridostigmine and anecdotal evidence suggests that rituximab should be considered as second-line immunosuppression. Thymectomy is indicated in any patient with a thymoma, and consideration should be given in acetylcholine receptor (AChR) positive JMG allowing time for spontaneous remission. The benefit is less clear in ocular JMG and is not advised in MuSK-JMG. Children experiencing a myasthenic crisis require urgent hospital admission with access to the intensive care unit. PLEX is preferred over IVIG due to rapid onset of action, but this needs to be balanced with feasibility in very young children. Key questions remain in the management of JMG: when to initiate both first- and second-line treatments, choosing between steroid-sparing agents, and determining the optimal dose and treatment duration. We feel that given the rarity of this disease, the establishment of national registries and collaboration across groups will be needed to address these issues and facilitate future drug trials in JMG.
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Affiliation(s)
- Karen O'Connell
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - Sithara Ramdas
- Department of Paediatric Neurology, John Radcliffe Hospital, Oxford, United Kingdom
| | - Jacqueline Palace
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
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14
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Vissing J, Jacob S, Fujita KP, O'Brien F, Howard JF. 'Minimal symptom expression' in patients with acetylcholine receptor antibody-positive refractory generalized myasthenia gravis treated with eculizumab. J Neurol 2020; 267:1991-2001. [PMID: 32189108 PMCID: PMC7320935 DOI: 10.1007/s00415-020-09770-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 02/18/2020] [Accepted: 02/20/2020] [Indexed: 01/14/2023]
Abstract
Background The efficacy and tolerability of eculizumab were assessed in REGAIN, a 26-week, phase 3, randomized, double-blind, placebo-controlled study in anti-acetylcholine receptor antibody-positive (AChR+) refractory generalized myasthenia gravis (gMG), and its open-label extension. Methods Attainment of ‘minimal symptom expression’ was evaluated using patient-reported outcome measures of gMG symptoms [MG activities of daily living scale (MG-ADL), 15-item MG quality of life questionnaire (MG-QOL15)] at the completion of REGAIN and during the open-label extension. ‘Minimal symptom expression’ was defined as MG-ADL total score of 0–1 or MG-QOL15 total score of 0–3. Results At REGAIN week 26, more eculizumab-treated patients achieved ‘minimal symptom expression’ versus placebo [MG-ADL: 21.4% vs 1.7%; difference 19.8%; 95% confidence interval (CI) 8.5, 31.0; p = 0.0007; MG-QOL15: 16.1% vs 1.7%; difference 14.4%; 95% CI 4.3, 24.6; p = 0.0069]. During the open-label extension, the proportion of patients in the placebo/eculizumab group who achieved ‘minimal symptom expression’ increased after initiating eculizumab treatment and was sustained through 130 weeks of open-label eculizumab (MG-ADL: 1.7 to 27.8%; MG-QOL15: 1.7 to 19.4%). At extension study week 130, similar proportions of patients in the eculizumab/eculizumab and placebo/eculizumab groups achieved ‘minimal symptom expression’ (MG-ADL: 22.9% and 27.8%, respectively, p = 0.7861; MG-QOL15: 14.3% and 19.4%, respectively, p = 0.7531). The long-term tolerability of eculizumab was consistent with previous reports. Conclusions Patients with AChR+ refractory gMG who receive eculizumab can achieve sustained ‘minimal symptom expression’ based on patient-reported outcomes. ‘Minimal symptom expression’ may be a useful tool in measuring therapy effectiveness in gMG. Trial registration ClinicalTrials.gov NCT01997229, NCT02301624. Electronic supplementary material The online version of this article (10.1007/s00415-020-09770-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- John Vissing
- Department of Neurology, Copenhagen Neuromuscular Center, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100, Copenhagen, Denmark.
| | - Saiju Jacob
- Queen Elizabeth Neuroscience Centre and Wellcome Trust Clinical Research Facility, University Hospitals Birmingham NHS Foundation Trust, Mindelsohn Way, Edgbaston, Birmingham, B15 2WB, UK
| | - Kenji P Fujita
- Alnylam Pharmaceuticals, 675 West Kendall Street, Cambridge, MA, 02142, USA
- Formerly Alexion Pharmaceuticals, 121 Seaport Boulevard, Boston, MA, 02210, USA
| | - Fanny O'Brien
- Alexion Pharmaceuticals, 121 Seaport Boulevard, Boston, MA, 02210, USA
| | - James F Howard
- Department of Neurology, University of North Carolina, 170 Manning Drive, Chapel Hill, NC, 27599-7025, USA
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15
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Maintenance immunosuppression in myasthenia gravis, an update. J Neurol Sci 2019; 410:116648. [PMID: 31901719 DOI: 10.1016/j.jns.2019.116648] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 11/25/2019] [Accepted: 12/24/2019] [Indexed: 01/08/2023]
Abstract
Therapies for myasthenia gravis (MG) include symptomatic and immunosuppressive/immunomodulatory treatment. Options for immunosuppression include corticosteroids, azathioprine, mycophenolate mofetil, cyclosporine, tacrolimus, methotrexate, rituximab, cyclophosphamide, eculizumab, intravenous immunoglobulin, subcutaneous immunoglobulin, plasmapheresis, and thymectomy. The practical aspects of long-term immunosuppressive therapy in MG are critically reviewed in this article. Application of one or more of these specific therapies is guided based on known efficacy, adverse effect profile, particular disease subtype and severity, and patient co-morbidities.
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16
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Abstract
Objectives: Myasthenia gravis (MG) may be refractory to traditional therapies. Quality of life (QOL) and disease burden in patients with refractory and nonrefractory MG were compared using Myasthenia Gravis Foundation of America MG Patient Registry data. Methods: Adults aged 18 years or older with MG diagnosed ≥2 years before enrollment were included. Participants with refractory MG had received ≥2 previous and 1 current MG treatment and had MG Activities of Daily Living Scale total score ≥6 at enrollment; other participants had nonrefractory MG. MG QOL 15-item scale (MG-QOL15) scores were compared. Results: In total, 56 participants with refractory and 717 participants with nonrefractory MG enrolled. Participants with refractory MG had significantly higher mean (SD) MG-QOL15 total scores [31.4 (11.1) vs. 20.8 (15.0), P < 0.0001] and were more likely to have had exacerbations, emergency department visits, and recent hospitalizations. Conclusions: Participants with refractory MG experience worse QOL and greater clinical burden than those with nonrefractory disease.
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17
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Intravenous cyclophosphamide monthly pulses in refractory myasthenia gravis. J Neurol 2019; 267:674-678. [DOI: 10.1007/s00415-019-09622-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 09/19/2019] [Accepted: 11/03/2019] [Indexed: 02/04/2023]
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18
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Barnett C, Tabasinejad R, Bril V. Current pharmacotherapeutic options for myasthenia gravis. Expert Opin Pharmacother 2019; 20:2295-2303. [PMID: 31670984 DOI: 10.1080/14656566.2019.1682548] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Introduction: Novel options for immune-based therapy in myasthenia gravis are improving the therapeutic outlook for patients. Multiple clinical trials on immunomodulation, complement inhibitors, and FcR inhibitors are providing evidence for novel immune-based therapies that promise to improve outcomes in myasthenia patients. These more focused immune treatments are reviewed in this paper.Areas covered: This paper outlines classical treatment for myasthenia gravis and then reviews recent clinical trial evidence for novel immune therapies, particularly complement inhibitors and FcR inhibitors. Further, as immune therapies expand in other areas of medicine, such as oncology, iatrogenic myasthenia is being observed as a complication of some novel treatments.Expert opinion: Exciting new options to help patients with myasthenia gravis are now available or in phase 3 trials based on promising phase 2 results. Manipulation of the immune system can also lead to iatrogenic MG. Although novel treatments can improve care for myasthenia gravis patients, future developments that prevent the production of specific abnormal auto-antibodies are desirable.
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Affiliation(s)
- Carolina Barnett
- Department of Medicine (Neurology), University Health Network, University of Toronto - Neurology, Toronto, Ontario, Canada
| | - Raha Tabasinejad
- Department of Medicine (Neurology), University Health Network, University of Toronto - Neurology, Toronto, Ontario, Canada
| | - Vera Bril
- Department of Medicine (Neurology), University Health Network, University of Toronto - Neurology, Toronto, Ontario, Canada
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19
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Harris L, Aban IB, Xin H, Cutter G. Employment in refractory myasthenia gravis: A Myasthenia Gravis Foundation of America Registry analysis. Muscle Nerve 2019; 60:700-706. [PMID: 31478207 PMCID: PMC6900169 DOI: 10.1002/mus.26694] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 08/28/2019] [Accepted: 08/28/2019] [Indexed: 11/11/2022]
Abstract
INTRODUCTION Labor-market participation is potentially very difficult for patients with refractory myasthenia gravis (MG). In this study, employment status and work absences are compared between refractory and nonrefractory MG. METHODS Adults (aged 18-64 years, all diagnosed ≥2 years previously) were included if enrolled in the Myasthenia Gravis Foundation of America Patient Registry during July 2013 to February 2018. RESULTS Seventy-six patients (9.2%) had refractory and 749 (90.8%) had nonrefractory disease; demographic data did not differ between groups. Relative to the nonrefractory group, the refractory group patients were more than twice as likely to work fewer hours per week (odds ratio [95% confidence interval]: currently employed, 2.777 [1.640-4.704]; employed over previous 6 months, 2.643 [1.595-4.380]), but those employed were not more likely to be absent from work. DISCUSSION Because absence from the labor market adversely affects quality of life and personal finances, these findings reaffirm the considerable disease burden associated with refractory MG.
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Affiliation(s)
- Linda Harris
- Formerly of Alexion Pharmaceuticals, Inc., Boston, Massachusetts
| | - Inmaculada B Aban
- Department of Biostatistics, University of Alabama at Birmingham, Birmingham, Alabama
| | - Haichang Xin
- Formerly of the Department of Health Care Organization and Policy, University of Alabama at Birmingham, Birmingham, Alabama
| | - Gary Cutter
- Department of Biostatistics, University of Alabama at Birmingham, Birmingham, Alabama
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20
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Long-term efficacy and safety of eculizumab in Japanese patients with generalized myasthenia gravis: A subgroup analysis of the REGAIN open-label extension study. J Neurol Sci 2019; 407:116419. [PMID: 31698177 DOI: 10.1016/j.jns.2019.08.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 08/01/2019] [Accepted: 08/02/2019] [Indexed: 12/31/2022]
Abstract
The terminal complement inhibitor eculizumab was shown to improve myasthenia gravis-related symptoms in the 26-week, phase 3, randomized, double-blind, placebo-controlled REGAIN study (NCT01997229). In this 52-week sub-analysis of the open-label extension of REGAIN (NCT02301624), eculizumab's efficacy and safety were assessed in 11 Japanese and 88 Caucasian patients with anti-acetylcholine receptor antibody-positive refractory generalized myasthenia gravis. For patients who had received placebo during REGAIN, treatment with open-label eculizumab resulted in generally similar outcomes in the Japanese and Caucasian populations. Rapid improvements were maintained for 52 weeks, assessed by change in score from open-label extension baseline to week 52 (mean [standard error]) using the following scales (in Japanese and Caucasian patients, respectively): Myasthenia Gravis Activities of Daily Living (-2.4 [1.34] and - 3.3 [0.65]); Quantitative Myasthenia Gravis (-2.9 [1.98] and - 4.3 [0.79]); Myasthenia Gravis Composite (-4.5 [2.63] and - 4.9 [1.19]); and Myasthenia Gravis Quality of Life 15-item questionnaire (-8.6 [5.68] and - 6.5 [1.93]). Overall, the safety of eculizumab was consistent with its known safety profile. In this interim sub-analysis, the efficacy and safety of eculizumab in Japanese and Caucasian patients were generally similar, and consistent with the overall REGAIN population.
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21
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Harris L, Graham S, MacLachlan S, Exuzides A, Jacob S. Healthcare resource utilization by patients with treatment-refractory myasthenia gravis in England. J Med Econ 2019; 22:691-697. [PMID: 30841772 DOI: 10.1080/13696998.2019.1592180] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Aims: To examine healthcare resource utilization associated with refractory myasthenia gravis (MG) in England. Materials and methods: This was a retrospective cohort study of linked data from the Clinical Practice Research Datalink and the Hospital Episode Statistics database collected between 1997 and 2016. Included patients were ≥18 years of age at the index MG diagnosis. Patients with refractory MG were identified using an algorithm based on treatments received. Healthcare resource utilization since the index date was compared between refractory and non-refractory cohorts. Results: The study included 1149 patients with MG, of whom 66 (5.7%) were refractory. Sex and age at diagnosis did not significantly differ between the refractory and non-refractory cohorts. Rates of healthcare resource utilization per person-year were significantly higher (p < .05) for patients with refractory compared to non-refractory MG for GP visits, visits to other healthcare professionals, outpatient visits and inpatient hospitalization. Patients in the refractory cohort spent more total days hospitalized since the index visit than patients in the non-refractory cohort (median, 33 vs. 16 days [p < .0001]). Limitations: The algorithm for identifying refractory patients did not include clinical criteria. Also, treatments administered in hospitals or by specialists were not available in the databases. Conclusions: Patients in England with refractory MG more often visit healthcare providers, are hospitalized and visit an emergency room than patients with non-refractory MG.
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Affiliation(s)
| | | | | | | | - Saiju Jacob
- d University Hospitals Birmingham , Birmingham , UK
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22
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Muppidi S, Utsugisawa K, Benatar M, Murai H, Barohn RJ, Illa I, Jacob S, Vissing J, Burns TM, Kissel JT, Nowak RJ, Andersen H, Casasnovas C, de Bleecker JL, Vu TH, Mantegazza R, O'Brien FL, Wang JJ, Fujita KP, Howard JF. Long-term safety and efficacy of eculizumab in generalized myasthenia gravis. Muscle Nerve 2019; 60:14-24. [PMID: 30767274 PMCID: PMC6619057 DOI: 10.1002/mus.26447] [Citation(s) in RCA: 102] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/10/2019] [Indexed: 01/16/2023]
Abstract
Introduction: Eculizumab is effective and well tolerated in patients with antiacetylcholine receptor antibody‐positive refractory generalized myasthenia gravis (gMG; REGAIN; NCT01997229). We report an interim analysis of an open‐label extension of REGAIN, evaluating eculizumab's long‐term safety and efficacy. Methods: Eculizumab (1,200 mg every 2 weeks for 22.7 months [median]) was administered to 117 patients. Results: The safety profile of eculizumab was consistent with REGAIN; no cases of meningococcal infection were reported during the interim analysis period. Myasthenia gravis exacerbation rate was reduced by 75% from the year before REGAIN (P < 0.0001). Improvements with eculizumab in activities of daily living, muscle strength, functional ability, and quality of life in REGAIN were maintained through 3 years; 56% of patients achieved minimal manifestations or pharmacological remission. Patients who had received placebo during REGAIN experienced rapid and sustained improvements during open‐label eculizumab (P < 0.0001). Discussion: These findings provide evidence for the long‐term safety and sustained efficacy of eculizumab for refractory gMG. Muscle Nerve 2019 See editorial on pages 7–9 in this issue.
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Affiliation(s)
- Srikanth Muppidi
- Department of Neurology and Neurosciences, Stanford University School of Medicine, Stanford, California, USA
| | | | - Michael Benatar
- Department of Neurology, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Hiroyuki Murai
- Department of Neurology, International University of Health and Welfare, Narita, Japan
| | - Richard J Barohn
- Department of Neurology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Isabel Illa
- Neurology Department, Hospital Sant Pau, Autonomous University of Barcelona, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Spain
| | - Saiju Jacob
- Queen Elizabeth Neuroscience Centre and Wellcome Trust Clinical Research Facility, University Hospital Birmingham, Birmingham, United Kingdom
| | - John Vissing
- Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Ted M Burns
- Department of Neurology, University of Virginia Health System, Charlottesville, Virginia, USA
| | - John T Kissel
- Department of Neurology, The Ohio State University, Columbus, Ohio, USA
| | - Richard J Nowak
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, Connecticut, USA
| | - Henning Andersen
- Department of Neurology, Aarhus University Hospital, Aarhus, Denmark
| | - Carlos Casasnovas
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Spain.,Department of Neurology, Bellvitge University Hospital, Barcelona, Spain
| | - Jan L de Bleecker
- Neuromuscular Reference Centre, Ghent University Hospital, Ghent, Belgium
| | - Tuan H Vu
- Department of Neurology, University of South Florida, Tampa, Florida, USA
| | - Renato Mantegazza
- Foundation of the Carlo Besta Neurological Institute, IRCSS, Milan, Italy
| | | | | | | | - James F Howard
- Department of Neurology, University of North Carolina, Chapel Hill, North Carolina, USA
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23
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Schneider-Gold C, Hagenacker T, Melzer N, Ruck T. Understanding the burden of refractory myasthenia gravis. Ther Adv Neurol Disord 2019; 12:1756286419832242. [PMID: 30854027 PMCID: PMC6399761 DOI: 10.1177/1756286419832242] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 01/28/2019] [Indexed: 11/15/2022] Open
Abstract
Myasthenia gravis (MG) is an autoantibody-mediated disease that compromises the acetylcholine receptors or associated structures of the postsynaptic membrane of the neuromuscular junction. This leads to impaired neuromuscular transmission and subsequent fluctuating fatigability and weakness of ocular, bulbar, and limb skeletal muscles. Over the past few decades, there have been significant advances in our understanding of the disease pathophysiology and improvements in prognosis due to intensive care medicine and immunomodulation. Despite this, an estimated 10–20% of patients with MG do not achieve an adequate response, are intolerant to conventional treatment, or require chronic treatment with intravenous immunoglobulins or plasma separation procedures. Such patients are regarded as having MG that is ‘refractory’ to treatment and may represent a distinct clinical subgroup. Because the majority of patients with MG have well-controlled disease, the burden of illness in the minority with refractory disease is poorly understood and may be underestimated. However, clinically these patients are liable to experience extreme fatigue, considerable disability owing to uncontrolled symptoms, and frequent myasthenic crises and hospitalizations. Both acute adverse effects and an increased risk of comorbidity from treatment regimens may contribute to reduced quality of life. As yet, little is known concerning the impact of refractory MG on mental health and health-related quality of life. This review aims to highlight the burden of disease and unmet needs in patients with refractory MG.
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Affiliation(s)
- Christiane Schneider-Gold
- Department of Neurology, St. Josef-Hospital, Ruhr-University Bochum, Gudrunstrasse 56, Bochum, D-44791, Germany
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24
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Howard JF, Utsugisawa K, Benatar M, Murai H, Barohn RJ, Illa I, Jacob S, Vissing J, Burns TM, Kissel JT, Muppidi S, Nowak RJ, O'Brien F, Wang JJ, Mantegazza R. Safety and efficacy of eculizumab in anti-acetylcholine receptor antibody-positive refractory generalised myasthenia gravis (REGAIN): a phase 3, randomised, double-blind, placebo-controlled, multicentre study. Lancet Neurol 2017; 16:976-986. [PMID: 29066163 DOI: 10.1016/s1474-4422(17)30369-1] [Citation(s) in RCA: 408] [Impact Index Per Article: 58.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 09/20/2017] [Accepted: 09/21/2017] [Indexed: 01/30/2023]
Abstract
BACKGROUND Complement is likely to have a role in refractory generalised myasthenia gravis, but no approved therapies specifically target this system. Results from a phase 2 study suggested that eculizumab, a terminal complement inhibitor, produced clinically meaningful improvements in patients with anti-acetylcholine receptor antibody-positive refractory generalised myasthenia gravis. We further assessed the efficacy and safety of eculizumab in this patient population in a phase 3 trial. METHODS We did a phase 3, randomised, double-blind, placebo-controlled, multicentre study (REGAIN) in 76 hospitals and specialised clinics in 17 countries across North America, Latin America, Europe, and Asia. Eligible patients were aged at least 18 years, with a Myasthenia Gravis-Activities of Daily Living (MG-ADL) score of 6 or more, Myasthenia Gravis Foundation of America (MGFA) class II-IV disease, vaccination against Neisseria meningitides, and previous treatment with at least two immunosuppressive therapies or one immunosuppressive therapy and chronic intravenous immunoglobulin or plasma exchange for 12 months without symptom control. Patients with a history of thymoma or thymic neoplasms, thymectomy within 12 months before screening, or use of intravenous immunoglobulin or plasma exchange within 4 weeks before randomisation, or rituximab within 6 months before screening, were excluded. We randomly assigned participants (1:1) to either intravenous eculizumab or intravenous matched placebo for 26 weeks. Dosing for eculizumab was 900 mg on day 1 and at weeks 1, 2, and 3; 1200 mg at week 4; and 1200 mg given every second week thereafter as maintenance dosing. Randomisation was done centrally with an interactive voice or web-response system with patients stratified to one of four groups based on MGFA disease classification. Where possible, patients were maintained on existing myasthenia gravis therapies and rescue medication was allowed at the study physician's discretion. Patients, investigators, staff, and outcome assessors were masked to treatment assignment. The primary efficacy endpoint was the change from baseline to week 26 in MG-ADL total score measured by worst-rank ANCOVA. The efficacy population set was defined as all patients randomly assigned to treatment groups who received at least one dose of study drug, had a valid baseline MG-ADL assessment, and at least one post-baseline MG-ADL assessment. The safety analyses included all randomly assigned patients who received eculizumab or placebo. This trial is registered with ClinicalTrials.gov, number NCT01997229. FINDINGS Between April 30, 2014, and Feb 19, 2016, we randomly assigned and treated 125 patients, 62 with eculizumab and 63 with placebo. The primary analysis showed no significant difference between eculizumab and placebo (least-squares mean rank 56·6 [SEM 4·5] vs 68·3 [4·5]; rank-based treatment difference -11·7, 95% CI -24·3 to 0·96; p=0·0698). No deaths or cases of meningococcal infection occurred during the study. The most common adverse events in both groups were headache and upper respiratory tract infection (ten [16%] for both events in the eculizumab group and 12 [19%] for both in the placebo group). Myasthenia gravis exacerbations were reported by six (10%) patients in the eculizumab group and 15 (24%) in the placebo group. Six (10%) patients in the eculizumab group and 12 (19%) in the placebo group required rescue therapy. INTERPRETATION The change in the MG-ADL score was not statistically significant between eculizumab and placebo, as measured by the worst-rank analysis. Eculizumab was well tolerated. The use of a worst-rank analytical approach proved to be an important limitation of this study since the secondary and sensitivity analyses results were inconsistent with the primary endpoint result; further research into the role of complement is needed. FUNDING Alexion Pharmaceuticals.
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Affiliation(s)
- James F Howard
- Department of Neurology, University of North Carolina, Chapel Hill, NC, USA.
| | | | - Michael Benatar
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Hiroyuki Murai
- Department of Neurology, International University of Health and Welfare, Narita, Japan
| | - Richard J Barohn
- Department of Neurology, University of Kansas Medical Center, Kansas City, KA, USA
| | - Isabel Illa
- Neurology Department, Hospital Sant Pau, Universitat Autònoma Barcelona, Barcelona, Spain
| | - Saiju Jacob
- Queen Elizabeth Neuroscience Centre, Wellcome Trust Clinical Research Facility, University Hospitals of Birmingham, Birmingham, UK
| | - John Vissing
- Rigshospitalet, Department of Neurology, University of Copenhagen, Copenhagen, Denmark
| | - Ted M Burns
- Department of Neurology, University of Virginia Health System, Charlottesville, VA, USA
| | - John T Kissel
- Department of Neurology, Ohio State University, Columbus, OH, USA
| | - Srikanth Muppidi
- Department of Neurology and Neurosciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Richard J Nowak
- Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
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Verschuuren J, Strijbos E, Vincent A. Neuromuscular junction disorders. HANDBOOK OF CLINICAL NEUROLOGY 2017; 133:447-66. [PMID: 27112691 DOI: 10.1016/b978-0-444-63432-0.00024-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Diseases of the neuromuscular junction comprise a wide range of disorders. Antibodies, genetic mutations, specific drugs or toxins interfere with the number or function of one of the essential proteins that control signaling between the presynaptic nerve ending and the postsynaptic muscle membrane. Acquired autoimmune disorders of the neuromuscular junction are the most common and are described here. In myasthenia gravis, antibodies to acetylcholine receptors or to proteins involved in receptor clustering, particularly muscle-specific kinase, cause direct loss of acetylcholine receptors or interfere with the agrin-induced acetylcholine receptor clustering necessary for efficient neurotransmission. In the Lambert-Eaton myasthenic syndrome (LEMS), loss of the presynaptic voltage-gated calcium channels results in reduced release of the acetylcholine transmitter. The conditions are generally recognizable clinically and the diagnosis confirmed by serologic testing and electromyography. Screening for thymomas in myasthenia or small cell cancer in LEMS is important. Fortunately, a wide range of symptomatic treatments, immunosuppressive drugs, or other immunomodulating therapies is available. Future research is directed to understanding the pathogenesis, discovering new antigens, and trying to develop disease-specific treatments.
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Affiliation(s)
- Jan Verschuuren
- Department of Neurology, Leiden University Medical Centre, Leiden, The Netherlands.
| | - Ellen Strijbos
- Department of Neurology, Leiden University Medical Centre, Leiden, The Netherlands
| | - Angela Vincent
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford, UK
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26
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Maintenance immunosuppression in myasthenia gravis. J Neurol Sci 2016; 369:294-302. [DOI: 10.1016/j.jns.2016.08.057] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 07/20/2016] [Accepted: 08/26/2016] [Indexed: 11/17/2022]
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27
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Evoli A, Iorio R, Bartoccioni E. Overcoming challenges in the diagnosis and treatment of myasthenia gravis. Expert Rev Clin Immunol 2015; 12:157-68. [PMID: 26675896 DOI: 10.1586/1744666x.2016.1110487] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In recent years, the discovery of new autoantigens and the use of sensitive assays have expanded the clinical spectrum of myasthenia gravis (MG). In particular, antibodies binding to clustered acetylcholine receptors and to the low-density lipoprotein receptor-related protein 4 have not only bridged a significant gap in diagnosis but also have relevant clinical implications. MG management includes different therapeutic options, from symptomatic agents as the only therapy in mildly affected cases to combined long-term immunosuppression and thymectomy in patients with severe disabling disease. MG biological diversity can influence the response to therapies and should be taken into account when planning treatment. Biologic agents are promising, though their use is currently limited to patients with refractory disease.
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Affiliation(s)
- Amelia Evoli
- a Institute of Neurology , Catholic University , Roma , Italy
| | - Raffaele Iorio
- a Institute of Neurology , Catholic University , Roma , Italy.,b Don Gnocchi ONLUS Foundation , Milan , Italy
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