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Wahbi K, Bassez G, Duchateau J, Salort-Campana E, Vicart S, Desaphy JF, Labombarda F, Sellal JM, Deharo JC. Expert opinion on mexiletine treatment in adult patients with myotonic dystrophy. Arch Cardiovasc Dis 2024; 117:450-456. [PMID: 38677940 DOI: 10.1016/j.acvd.2024.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 03/13/2024] [Accepted: 03/25/2024] [Indexed: 04/29/2024]
Abstract
In France, mexiletine - a class I antiarrhythmic drug - can be prescribed for the symptomatic treatment of myotonia of the skeletal muscles in adult patients with myotonic dystrophy under a compassionate use programme. Mexiletine is used according to its summary of product characteristics, which describes its use for myotonia treatment in adult patients with non-dystrophic myotonia, a different neuromuscular condition without cardiac involvement. A cardiac assessment is required prior to initiation and throughout treatment due to potential proarrhythmic effects. The presence of conduction system disease, the most common cardiac manifestation of myotonic dystrophy, mandates repeated cardiac evaluations in patients with this condition, and becomes even more important when they are given mexiletine. A group of experts, including three neurologists and five cardiologists from French neuromuscular reference centres, were involved in a task force to develop a treatment algorithm to guide mexiletine use in myotonic dystrophy. The recommendations are based on data from a literature review of the safety of mexiletine-treated patients with myotonic dystrophy, the compassionate use protocol for mexiletine and the personal clinical experience of the experts. The main conclusion of the expert group is that, although existing safety data in mexiletine-treated patients with myotonic dystrophy are reassuring, cardiac assessments should be reinforced in such patients compared with mexiletine-treated patients with non-dystrophic myotonia. This expert opinion to guide mexiletine treatment in patients with myotonic dystrophy should help to reduce the risk of severe adverse events and facilitate interactions between specialists involved in the routine care of patients with myotonic dystrophy.
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Affiliation(s)
- Karim Wahbi
- Centre de Référence des Maladies Neuromusculaires Nord/Est/Île-de-France, Cardiology Department, Cochin Hospital, AP-HP, Paris Cité University, 75014 Paris, France; Paris Cardiovascular Research Centre (PARCC), Inserm Unit 970, Georges-Pompidou European Hospital, 75015 Paris, France.
| | - Guillaume Bassez
- Constitutive Reference Centre for Neuromuscular Diseases, Neuro-Myology Department, Pitié-Salpêtrière University Hospital, AP-HP, 75013 Paris, France
| | - Josselin Duchateau
- Department of Cardiology, Electrophysiology and Cardiac Pacing, Haut l'Evêque Cardiology Hospital, CHU de Bordeaux, 33604 Pessac, France
| | - Emmanuelle Salort-Campana
- Reference Centre for Neuromuscular Diseases PACA/Réunion/Rhône Alpes, La Timone Hospital, CHU de Marseille, AP-HM, 13385 Marseille, France; FILNEMUS, Neuromuscular Rare Diseases Healthcare Professional Network, La Timone Hospital, CHU de Marseille, AP-HM, 13385 Marseille, France
| | - Savine Vicart
- Muscle Channelopathies Reference Centre, Neuro-Myology Department, Pitié-Salpêtrière University Hospital, AP-HP, Inserm UMR 974, Institute of Myology, Sorbonne University, 75013 Paris, France
| | - Jean-François Desaphy
- Department of Precision and Regenerative Medicine and Ionian Area, School of Medicine, University of Bari Aldo Moro, 70124 Bari, Italy
| | - Fabien Labombarda
- Cardiology Department, CHU de Caen, UR 4650, UNICAEN, 14000 Caen, France
| | | | - Jean-Claude Deharo
- Cardiology Department, La Timone Hospital, CHU de Marseille, AP-HM, 13385 Marseille, France; C2VN, Aix-Marseille Université, 13005 Marseille, France
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Vicart S, Péréon Y, Ghorab K, Pegat A, Dufresne R, Zozulya-Weidenfeller A, Noury JB, Nadaj-Pakleza A, Tard C, Sacconi S. Self-reported outcomes and quality of life of patients with non-dystrophic myotonia: The French IMPACT 2022 survey. Rev Neurol (Paris) 2024:S0035-3787(24)00530-7. [PMID: 38811249 DOI: 10.1016/j.neurol.2024.04.007] [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: 11/21/2023] [Revised: 04/08/2024] [Accepted: 04/21/2024] [Indexed: 05/31/2024]
Abstract
Non-dystrophic myotonias (NDM) are disabling genetic diseases that impact quality of life. To reduce the impact of NDM, patients develop coping strategies such as lifestyle adaptation and avoiding key triggers. To understand how myotonia affects patients' lives, the IMPACT survey, an online questionnaire on patient-reported outcomes, was developed based on international IMPACT questionnaire. The French IMPACT 2022 survey was completed by 47 NDM French patients. Besides muscle stiffness (98%), patients reported muscle pain (83%), falls (70%) and anxiety (77%). These issues negatively impacted abilities to work/study (49%), daily life at home (49%) and overall mobility outside (49%). Most patients (96%) reported ongoing pharmacological treatment (mexiletine, 91%) associated with improvement in muscle stiffness (100%) and reduction in falls (94%), muscle pain (87%) and anxiety (80%). Patients were moderately satisfied (19.1%), satisfied (42.6%) and very satisfied (29.8%) with the current management; 32% rated their quality of life positively (≥ 8 on 10-point scale). In conclusion, this French survey confirms the impact of myotonia on daily life and quality of life. The improvement in patient-reported outcomes in treated participants highlights the importance of managing myotonia with effective treatments. More work should be initiated to assess the importance of NDM symptom management and patients' adherence and compliance to treatment.
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Affiliation(s)
- S Vicart
- National Centre for Muscle Channelopathies, Service of Neuro-Myology, University Hospital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Sorbonne University, INSERM UMR 974, Institute of Myology, 47-83 Boulevard de l'Hôpital 75013 Paris, France.
| | - Y Péréon
- Reference Centre for Neuromuscular Disorders AOC, Euro-NMD, Filnemus, CHU de Nantes, Hôtel-Dieu, 1, place Alexis-Ricordeau, 44000 Nantes, France
| | - K Ghorab
- Reference Centre for Rare Peripheral Neuropathies, CHU de Limoges, 2, avenue Martin-Luther-King, 87000 Limoges, France
| | - A Pegat
- Hospices civils de Lyon, Department of ENMG and Neuromuscular Disorders, Reference Centre of Neuromuscular Disorders, Rhône Alpes, Neurological Hospital P.-Wertheimer, 59, boulevard Pinel, 69500 Bron, France
| | - R Dufresne
- Lupin Neurosciences, Landis+Gyr Strasse 1, 6300 Zug, Switzerland
| | | | - J-B Noury
- Reference Centre for Neuromuscular Disorders AOC, Inserm, LBAI, UMR1227, CHRU de Brest, boulevard Tanguy-Prigent, 29200 Brest, France
| | - A Nadaj-Pakleza
- Reference Centre for Neuromuscular Disorders NEIdF, Euro-NMD, Department of Neurology, Filnemus, hôpitaux universitaires de Strasbourg, 1, avenue Molière, 67200 Strasbourg, France
| | - C Tard
- U1172, Reference Centre for Neuromuscular Disorders Nord/Est/Île-de-France, Department of Neurology, Cognitive-Motor Expertise Unit, CHU de Lille, rue Michel-Polonowski, 59000 Lille, France
| | - S Sacconi
- Reference Centre for Neuromuscular Disorders, CHU de Nice, 30, voie Romaine, 06000 Nice, France
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Lloyd A, Rand K, Pike C, Ellis C. Preference-based utility weights for the Individualized Neuromuscular Quality of Life Questionnaire (INQoL), with a focus on non-dystrophic myotonia (NDM). THE EUROPEAN JOURNAL OF HEALTH ECONOMICS : HEPAC : HEALTH ECONOMICS IN PREVENTION AND CARE 2024:10.1007/s10198-024-01674-2. [PMID: 38416296 DOI: 10.1007/s10198-024-01674-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 01/18/2024] [Indexed: 02/29/2024]
Abstract
INTRODUCTION The Individualized Neuromuscular Quality of Life Questionnaire (INQoL) is used to measure quality of life in neuromuscular disorders such as non-dystrophic myotonia (NDM). Here we report methods to estimate utilities, with a focus on NDM, from this questionnaire based on two preference elicitation exercises. METHODS Eight items from the INQoL were selected with input from three neuromuscular disorder clinical experts with expertise in treating NDM. A discrete choice experiment (DCE) survey of UK general public respondents (n = 508) described outcomes defined by the INQoL items. The same 8 items were also valued using time trade-off (TTO) face-to-face interviews (n = 200). A hybrid regression modelling approach combined both datasets to inform the utility weights. RESULTS Hybrid modelling of DCE and TTO data in conjunction improved out-of-sample predictive accuracy. The selected INQoL utility model indicates substantial disutility associated with all eight dimensions of health, with the greatest losses associated with subjective items such as pain and depression. DISCUSSION The hybrid modelling approach allows us to combine data from the two methodologies and maximize the information from each to inform the utility weights for the INQoL. The TTO is the more conventional valuation method, but combined with the larger DCE study produced better descriptive coverage. This is a relatively novel method for estimating weights which we think is particularly well suited to economic evaluations of orphan drugs.
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Affiliation(s)
| | - Kim Rand
- Health Services Research Unit, Akershus University Hospital, Lørenskog, Norway
- Maths in Health B.V., Klimmen, The Netherlands
| | - Cleo Pike
- Acaster Lloyd Consulting Ltd, London, UK
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Elettreby AM, Elnaga AAA, Alsaied MA, Ewis DK, Sharkawy AM, Fareed R, Alderbi GM. Effectiveness and safety of mexiletine versus placebo in patients with myotonia: a systematic review and meta-analysis. Neurol Sci 2024:10.1007/s10072-024-07412-z. [PMID: 38403671 DOI: 10.1007/s10072-024-07412-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 02/16/2024] [Indexed: 02/27/2024]
Abstract
BACKGROUND The rare nature of dystrophic and non-dystrophic myotonia has limited the available evidence on the efficacy of mexiletine as a potential treatment. To address this gap, we conducted a systematic review and meta-analysis to evaluate the effectiveness and safety of mexiletine for both dystrophic and non-dystrophic myotonic patients. METHODS The search was conducted on various electronic databases up to March 2023, for randomized clinical trials (RCTs) comparing mexiletine versus placebo in myotonic patients. A risk of bias assessment was carried out, and relevant data was extracted manually into an online sheet. RevMan software (version 5.4) was employed for analysis. RESULTS A total of five studies, comprising 186 patients, were included in the meta-analysis. Our findings showed that mexiletine was significantly more effective than placebo in improving stiffness score (SMD = - 1.19, 95% CI [- 1.53, - 0.85]), as well as in reducing hand grip myotonia (MD = - 1.36 s, 95% CI [- 1.83, - 0.89]). Mexiletine also significantly improved SF-36 Physical and Mental Component Score in patients with non-dystrophic myotonia only. Regarding safety, mexiletine did not significantly alter ECG parameters but was associated with greater gastrointestinal symptoms (GIT) compared to placebo (RR 3.7, 95% CI [1.79, 7.64]). Other adverse events showed no significant differences. CONCLUSION The results support that mexiletine is effective and safe in myotonic patients; however, it is associated with a higher risk of GIT symptoms. Due to the scarcity of published RCTs and the prevalence of GIT symptoms, we recommend further well-designed RCTs testing various drug combinations to reduce GIT symptoms.
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Affiliation(s)
- Abdelrahman Mohammed Elettreby
- Faculty of Medicine, Mansoura University, El Gomhouria St, Mansoura, 35511, Egypt.
- Medical Research Group of Egypt, Negida Academy LLC, Arlington, MA, 02474, USA.
| | - Ahmed Abdullah Abo Elnaga
- Faculty of Medicine, Mansoura University, El Gomhouria St, Mansoura, 35511, Egypt
- Medical Research Group of Egypt, Negida Academy LLC, Arlington, MA, 02474, USA
| | - Mohamed Ahmed Alsaied
- Faculty of Medicine, Mansoura University, El Gomhouria St, Mansoura, 35511, Egypt
- Medical Research Group of Egypt, Negida Academy LLC, Arlington, MA, 02474, USA
| | - Dalia Kamal Ewis
- Medical Research Group of Egypt, Negida Academy LLC, Arlington, MA, 02474, USA
- Faculty of Medicine, Beni Suef University, Beni Suef, Egypt
| | - Aya Mohammed Sharkawy
- Medical Research Group of Egypt, Negida Academy LLC, Arlington, MA, 02474, USA
- Faculty of Medicine, South Valley University, Qena, Egypt
| | - Rahma Fareed
- Medical Research Group of Egypt, Negida Academy LLC, Arlington, MA, 02474, USA
- Faculty of Pharmacy, Beni Suef University, Beni Suef, Egypt
| | - Gehad Magdy Alderbi
- Medical Research Group of Egypt, Negida Academy LLC, Arlington, MA, 02474, USA
- Faculty of Pharmacy, Beni Suef University, Beni Suef, Egypt
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Das P, Panigrahi D. Autosomal Recessive Myotonia Congenita in an Adolescent Boy With Novel Mutation: A Case Report With Discussion on Management. Cureus 2024; 16:e53981. [PMID: 38469025 PMCID: PMC10927349 DOI: 10.7759/cureus.53981] [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] [Accepted: 02/10/2024] [Indexed: 03/13/2024] Open
Abstract
Congenital myotonia represents a rare group of genetically inherited conditions. It can be either autosomal dominant (Thomsen) or autosomal recessive (Becker). It is characterized by muscular hypertrophy, proximal weakness, and myotonia, or impaired relaxation after contraction. These are due to mutations in the CLC1 gene. A 14-year-old male child presented with complaints of gradually progressive weakness for five years. Weakness was more pronounced in the proximal muscle groups. The weakness worsened after rest and improved with activity. This led to absenteeism and affected his school performance. Clinical examination showed generalized muscular hypertrophy with pronounced hypertrophy of the calf muscles. A neurological examination showed significant myotonia and impaired relaxation after making a fist. The diagnosis of myotonia was confirmed by electromyography, which produced a dive-bomber sound on insertion. Next-generation sequencing revealed a homozygous eight-base pair insertion in exon 19 of the CLCN1 gene. This mutation has not been reported in the existing literature for myotonia congenita. The child was started on mexiletine and improved significantly. Presently, the patient is on regular medications and doing well on follow-up. Though rare, congenital myotonia is an important cause of neuromuscular weakness. It can be easily diagnosed with a thorough clinical examination and routine testing for myotonia in all children with weakness. The treatment is relatively simple and can give the patient significant relief. Myotonia can be easily diagnosed clinically, and pharmacotherapy and proper monitoring can remarkably improve patients' quality of life.
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Affiliation(s)
- Palash Das
- Pediatric Medicine, Kalinga Institute of Medical Sciences, Bhubaneshwar, IND
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Lidonnici D, Brambilla P, Ravasio R, Zozulya-Weidenfeller A, Beiderbeck A, van Aswegen M, Oliveira R, Sansone VA. Expert Insights from a Delphi-driven Neurologists' Panel: Real-world Mexiletine use in Patients with Myotonic Disorders in Italy. J Neuromuscul Dis 2024; 11:411-423. [PMID: 38306059 DOI: 10.3233/jnd-230115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2024]
Abstract
Background Myotonic disorders, such as non-dystrophic myotonias (NDMs) and myotonic dystrophies (DMs) are characterized by a delay in muscle relaxation after a contraction stimulus. There is general consensus that protocols to treat myotonia need to be implemented. Objective Mexiletine is the only pharmacological agent approved for the symptomatic treatment of myotonia in adult patients with NDM and is considered to be the first-line treatment for DMs; however, its production in Italy was halted in 2022 making its availability to patients problematic. Methods A panel of 8 Italian neurologists took part in a two-round Delphi panel between June and October 2022, analyzing the current use of mexiletine in Italian clinical practice. Results The panelists assist 1126 patients (69% DM type1, 18% NDM and 13% DM type2). Adult NDM patients receive, on average, 400-600 mg of mexiletine hydrochloride (HCl) while adult DM patients receive 100-600 mg, per day in the long-term. The severity of symptoms is considered the main reason to start mexiletine treatment for both NDM and DM patients. Mexiletine is reckoned to have a clinical impact for both NDM and DM patients, but currently drug access is problematic. Conclusions Mexiletine treatment is recognized to have a role in the reduction of the symptomatic burden for NDM and DM patients. Patient management could be improved by facilitating access to therapy and developing new drug formulations.
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Affiliation(s)
| | | | | | | | | | | | | | - Valeria A Sansone
- The NEMO Center, Neurorehabilitation Unit, University of Milan, ASST Niguarda Hospital, Milan, Italy
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Vicino A, Brugnoni R, Maggi L. Diagnostics in skeletal muscle channelopathies. Expert Rev Mol Diagn 2023; 23:1175-1193. [PMID: 38009256 DOI: 10.1080/14737159.2023.2288258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 11/22/2023] [Indexed: 11/28/2023]
Abstract
INTRODUCTION Skeletal muscle channelopathies (SMCs) are a heterogenous group of disorders, caused by mutations in skeletal ion channels leading to abnormal muscle excitability, resulting in either delayed muscle relaxation (myotonia) which characterizes non-dystrophic myotonias (NDMs), or membrane transient inactivation, causing episodic weakness, typical of periodic paralyses (PPs). AREAS COVERED SMCs include myotonia congenita, paramyotonia congenita, and sodium-channel myotonia among NDMs, and hyper-normokalemic, hypokalemic, or late-onset periodic paralyses among PPs. When suspecting an SMC, a structured diagnostic approach is required. Detailed personal and family history and clinical examination are essential, while neurophysiological tests should confirm myotonia and rule out alternative diagnosis. Moreover, specific electrodiagnostic studies are important to further define the phenotype of de novo cases and drive molecular analyses together with clinical data. Definite diagnosis is achieved through genetic testing, either with Sanger sequencing or multigene next-generation sequencing panel. In still unsolved patients, more advanced techniques, as exome-variant sequencing or whole-genome sequencing, may be considered in expert centers. EXPERT OPINION The diagnostic approach to SMC is still mainly based on clinical data; moreover, definite diagnosis is sometimes complicated by the difficulty to establish a proper genotype-phenotype correlation. Lastly, further studies are needed to allow the genetic characterization of unsolved patients.
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Affiliation(s)
- Alex Vicino
- Neurology IV Unit, Neuroimmunology and Neuromuscular Diseases, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
- Nerve-Muscle Unit, Neurology Service, Department of Clinical Neurosciences, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Raffaella Brugnoni
- Neurology IV Unit, Neuroimmunology and Neuromuscular Diseases, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Lorenzo Maggi
- Neurology IV Unit, Neuroimmunology and Neuromuscular Diseases, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
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Díaz-Manera J, Urtizberea JA, Schey C, Kole A, von Gallwitz P, Whiting A, Foerster D, Zozulya-Weidenfeller A. Impact of restricted access to, and low awareness of, mexiletine on people with myotonia: a real-world European survey. Neuromuscul Disord 2023; 33:208-217. [PMID: 36706619 DOI: 10.1016/j.nmd.2022.12.008] [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: 04/28/2022] [Revised: 12/06/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022]
Abstract
Although mexiletine effectively treats myotonia, supply disruptions affected Europe between 2008-2018. MyoPath was a mixed-methods, cross-sectional, market research survey conducted January-June 2018 to evaluate consequences of limited access to/awareness of mexiletine in people with myotonia. Part A: qualitative structured interviews (clinicians; advocates for adult patients); Part B: quantitative online questionnaire completed by people with self-reported history of myotonia. Part A: Interviews (clinicians, n=12; patient advocates, n=5; 12 countries) indicated poor mexiletine awareness among general neurologists. Patients chose between living with myotonia (other treatments were generally unsatisfactory) or importing mexiletine. Part B: Questionnaire respondents, myotonic dystrophy (DM)1, n=213; DM2, n=128; non-dystrophic myotonia (NDM), n=41; other n=8; (11 countries). Of the respondents, 76/390 (20%) people with awareness of/access to mexiletine described profound improvements in myotonia and health-related quality of life following treatment. Respondents with NDM had greatest mexiletine experience (n=28/41). Mexiletine was associated with fewer falls, less muscle stiffness, increased mobility. Treatment interruptions worsened myotonia and were associated with fatigue, pain, dysphagia, breathing difficulty, impaired digestion, poor sleep. However, 36/54 (67%) of currently treated people expressed anxiety about mexiletine's availability: this finding was expected (MyoPath was undertaken before mexiletine's approval in NDM). MyoPath provides the largest European exploration of patients' views regarding impact of mexiletine on myotonia. Anticipated effects of mexiletine differ between people with different myotonic disorders: myotonia is the main symptom in NDM but one of many potential symptoms affecting those with DM. Nevertheless, findings indicate substantial harm caused to people with myotonia when mexiletine awareness/access is limited.
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Affiliation(s)
- Jordi Díaz-Manera
- John Walton Muscular Dystrophy Research Centre, Newcastle University International Centre for Life, Newcastle upon Tyne, United Kingdom.
| | | | - Carina Schey
- Department of Epidemiology, University of Groningen, Groningen, the Netherlands
| | - Anna Kole
- admedicum® Business for Patients GmbH & Co KG, Cologne, Germany
| | | | - Amy Whiting
- admedicum® Business for Patients GmbH & Co KG, Cologne, Germany
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Altamura C, Saltarella I, Campanale C, Laghetti P, Desaphy JF. Drug repurposing in skeletal muscle ion channelopathies. Curr Opin Pharmacol 2023; 68:102329. [PMID: 36512979 DOI: 10.1016/j.coph.2022.102329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 10/26/2022] [Accepted: 11/02/2022] [Indexed: 12/14/2022]
Abstract
Skeletal muscle ion channelopathies are rare genetic diseases mainly characterized by myotonia (muscle stiffness) or periodic paralysis (muscle weakness). Here, we reviewed the available therapeutic options in non-dystrophic myotonias (NDM) and periodic paralyses (PP), which consists essentially in drug repositioning to address stiffness or weakness attacks. Empirical use followed by successful randomized clinical trials eventually led to the orphan drug designation and marketing authorization granting of mexiletine for NDM and dichlorphenamide for PP. Yet, these treatments neither consider the genetic cause of the diseases nor address the individual variability in drug response. Thus, ongoing research aims at the identification of repurposed drugs alternative to mexiletine and dichlorphenamide to allow personalization of treatment. This review highlights how drug repurposing may represent an efficient strategy in rare diseases, allowing reduction of drug development time and costs in a context in which the return on investment may be particularly challenging.
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Affiliation(s)
- Concetta Altamura
- Section of Pharmacology, Department of Precision and Regenerative Medicine, School of Medicine, University of Bari Aldo Moro, Piazza Giulo Cesare, 70124, Bari, Italy
| | - Ilaria Saltarella
- Section of Pharmacology, Department of Precision and Regenerative Medicine, School of Medicine, University of Bari Aldo Moro, Piazza Giulo Cesare, 70124, Bari, Italy
| | - Carmen Campanale
- Section of Pharmacology, Department of Precision and Regenerative Medicine, School of Medicine, University of Bari Aldo Moro, Piazza Giulo Cesare, 70124, Bari, Italy
| | - Paola Laghetti
- Section of Pharmacology, Department of Precision and Regenerative Medicine, School of Medicine, University of Bari Aldo Moro, Piazza Giulo Cesare, 70124, Bari, Italy
| | - Jean-François Desaphy
- Section of Pharmacology, Department of Precision and Regenerative Medicine, School of Medicine, University of Bari Aldo Moro, Piazza Giulo Cesare, 70124, Bari, Italy.
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Boreham H. Mexiletine in the Treatment of Non-dystrophic Myotonia: Interviews with Six Medical Experts. EUROPEAN MEDICAL JOURNAL 2022. [DOI: 10.33590/emj/10197860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Evidence from randomised controlled clinical trials demonstrates that mexiletine effectively controls myotonic symptoms with a well-described safety profile. Despite this, there are still a limited number of patients on this treatment, and physicians from expert neuromuscular centres may not be fully aware of the potential benefits of mexiletine treatment, including improvements in patients’ quality of life (QoL), the impact on activities of daily living, and the favourable safety profile, even in younger patients.
During this ‘Meet the Experts’ interview series, five neurologists experienced in the management of non-dystrophic myotonias (NDM), and one specialist cardiologist offered their expert insights on the clinical data and real-world evidence supporting the use of mexiletine in NDM.
Addressing patient concerns and encouraging treatment acceptance were highlighted as key steps to optimise outcomes from mexiletine therapy. The medical experts emphasised the importance of contextualising the favourable benefit-to-risk profile of mexiletine, particularly regarding cardiac safety concerns and drug monitoring requirements. The expert cardiologist further explained that, in their experience, the cardiac safety profile of mexiletine was no different in patients with NDM when compared to healthy controls used in clinical studies when used as directed.
When considering anti-myotonia treatment in patients with NDM, medical experts stressed that decision-making should be driven by the overall degree of myotonia. Healthcare professionals (HCP), therefore, need to look beyond basic clinical assessment to understand the true impact of myotonia on patients’ everyday lives.
Overall, these interviews highlighted the critical role that HCPs can play in leveraging the clinical data and managing patient expectations to ensure maximum treatment success when recommending mexiletine to patients with NDM.
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Cordenier A, Flamez A, de Ravel T, Gheldof A, Pannone L, De Asmundis C, Pappaert G, Bissay V. Case report: Coexistence of myotonia congenita and Brugada syndrome in one family. Front Neurol 2022; 13:1011956. [PMID: 36212636 PMCID: PMC9537820 DOI: 10.3389/fneur.2022.1011956] [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] [Received: 08/04/2022] [Accepted: 09/05/2022] [Indexed: 11/21/2022] Open
Abstract
Myotonia congenita is a rare neuromuscular disorder caused by CLCN1 mutations resulting in delayed muscle relaxation. Extramuscular manifestations are not considered to be present in chloride skeletal channelopathies, although recently some cardiac manifestations have been described. We report a family with autosomal dominant myotonia congenita and Brugada syndrome. Bearing in mind the previously reported cases of cardiac arrhythmias in myotonia congenita patients, we discuss the possible involvement of the CLCN1-gene mutations in primary cardiac arrhythmia.
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Affiliation(s)
- Ann Cordenier
- Department of Neurology, Center for Neurosciences, Vrije Universiteit Brussel (VUB), UZ-Brussel, Brussels, Belgium
- *Correspondence: Ann Cordenier
| | - Anja Flamez
- Department of Neurology, Center for Neurosciences, Vrije Universiteit Brussel (VUB), UZ-Brussel, Brussels, Belgium
| | - Thomy de Ravel
- Center for Medical Genetics, Vrije Universiteit Brussel (VUB), UZ-Brussel, Brussels, Belgium
| | - Alexander Gheldof
- Center for Medical Genetics, Vrije Universiteit Brussel (VUB), UZ-Brussel, Brussels, Belgium
| | - Luigi Pannone
- Heart Rhythm Management Centre, Vrije Universiteit Brussel (VUB), UZ-Brussel, Brussels, Belgium
| | - Carlo De Asmundis
- Heart Rhythm Management Centre, Vrije Universiteit Brussel (VUB), UZ-Brussel, Brussels, Belgium
| | - Gudrun Pappaert
- Heart Rhythm Management Centre, Vrije Universiteit Brussel (VUB), UZ-Brussel, Brussels, Belgium
| | - Véronique Bissay
- Department of Neurology, Center for Neurosciences, Vrije Universiteit Brussel (VUB), UZ-Brussel, Brussels, Belgium
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Chapman AM, Schurer M, Weijers L, Omar A, Lee H, Weidenfeller AZ, Ellis C, Sonecha S, Schneider-Gold C. Improving the understanding of how patients with non-dystrophic myotonia are selected for myotonia treatment with mexiletine (NaMuscla): outcomes of treatment impact using a European Delphi panel. BMC Neurol 2021; 21:467. [PMID: 34852780 PMCID: PMC8633892 DOI: 10.1186/s12883-021-02491-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 11/10/2021] [Indexed: 11/17/2022] Open
Abstract
Background Non-dystrophic myotonias (NDMs) comprise muscle chloride and sodium channelopathies due to genetic defects of the CLCN1- and SCN4A-channels. No licensed antimyotonic treatment has been available until approval of mexiletine (NaMuscla®) for adult patients by the EMA in December 2018. This Delphi panel aimed to understand how outcomes of the pivotal phase III Mexiletine study (MYOMEX) translate to real world practice and investigate health resource use, quality of life and the natural history of NDM to support economic modelling and facilitate patient access. Methods Nine clinical experts in treating NDM took part in a two-round Delphi panel. Their knowledge of NDM and previous use of mexiletine as an off-label treatment prior to NaMuscla’s approval ensured they could provide both qualitative context and quantitative estimates to support economic modelling comparing mexiletine (NaMuscla) to best supportive care. Consensus in four key areas was sought: healthcare resource utilization (HRU), treatment with mexiletine (NaMuscla), patient quality of life (QoL), and the natural history of disease. Concept questions were also asked, considering perceptions on the feasibility of mapping the validated Individualized Neuromuscular Quality of Life (INQoL) instrument to the generic EQ-5D™, and the potential impact on caregiver QoL. Results Consensus was achieved for key questions including the average long-term dosage of mexiletine (NaMuscla) in practice, the criteria for eligibility of myotonia treatment, the clinical importance of QoL outcomes in MYOMEX, the higher proportion of patients with increased QoL, and the reduction in the need for mental health resources for patients receiving mexiletine (NaMuscla). While consensus was not achieved for other questions, the results demonstrated that most experts felt mexiletine (NaMuscla) reduced the need for HRU and was expected to improve QoL. The QoL mapping exercise suggested that it is feasible to map domains of INQoL to EQ-5D. Points of interest for future research were identified, including that mexiletine (NaMuscla) may slow the annual decrease in QoL of patients over their lifetime, and a significant negative impact on QoL for some caregivers. Conclusions This project successfully provided data from an informed group of clinical experts, complementing the currently available clinical trial data for mexiletine (NaMuscla) to support patient access decisions. Supplementary Information The online version contains supplementary material available at 10.1186/s12883-021-02491-3.
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Affiliation(s)
| | | | | | - Amer Omar
- Lupin Atlantis Holdings SA, Zug, Switzerland
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