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Pigliasco F, Cafaro A, Barco S, Stella M, Mattioli F, Riva A, Mancardi MM, Lattanzi S, Bandettini R, Striano P, Cangemi G. Innovative LC-MS/MS method for therapeutic drug monitoring of fenfluramine and cannabidiol in the plasma of pediatric patients with epilepsy. J Pharm Biomed Anal 2024; 245:116174. [PMID: 38703746 DOI: 10.1016/j.jpba.2024.116174] [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: 02/12/2024] [Revised: 03/25/2024] [Accepted: 04/22/2024] [Indexed: 05/06/2024]
Abstract
We present a novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for quantifying fenfluramine (FFA), its active metabolite norfenfluramine (norFFA), and Epidyolex®, a pure cannabidiol (CBD) oral solution in plasma. Recently approved by the EMA for the adjunctive treatment of refractory seizures in patients with Dravet and Lennox-Gastaut syndromes aged above 2 years, FFA and CBD still do not have established therapeutic blood ranges, and thus need careful drug monitoring to manage potential pharmacokinetic and pharmacodynamic interactions. Our method, validated by ICH guidelines M10, utilizes a rapid extraction protocol from 100 µL of human plasma and a reversed-phase C-18 HPLC column, with deuterated internal standards. The Thermofisher Quantiva triple-quadrupole MS coupled with an Ultimate 3000 UHPLC allowed multiple reaction monitoring detection, ensuring precise analyte quantification. The assay exhibited linear responses across a broad spectrum of concentrations: ranging from 1.64 to 1000 ng/mL for both FFA and CBD, and from 0.82 to 500 ng/mL for norFFA. The method proves accurate and reproducible, free from matrix effect. Additionally, FFA stability in plasma at 4 °C and -20 °C for up to 7 days bolsters its clinical applicability. Plasma concentrations detected in patients samples, expressed as mean ± standard deviation, were 0.36 ± 0.09 ng/mL for FFA, 19.67 ± 1.22 ng/mL for norFFA. This method stands as a robust tool for therapeutic drug monitoring (TDM) of FFA and CBD, offering significant utility in assessing drug-drug interactions in co-treated patients, thus contributing to optimized patient care in complex therapeutic scenarios.
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Affiliation(s)
- Federica Pigliasco
- Chromatography and Mass Spectrometry Section, Central Laboratory of Analysis, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Alessia Cafaro
- Chromatography and Mass Spectrometry Section, Central Laboratory of Analysis, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Sebastiano Barco
- Chromatography and Mass Spectrometry Section, Central Laboratory of Analysis, IRCCS Istituto Giannina Gaslini, Genoa, Italy.
| | - Manuela Stella
- Gaslini Trial Centre, IRCCS Istituto Giannina Gaslini, Genoa, Italy; Pharmacology and Toxicology Unit, Department of Internal Medicine, University of Genoa, Genoa, Italy
| | - Francesca Mattioli
- Pharmacology and Toxicology Unit, Department of Internal Medicine, University of Genoa, Genoa, Italy; Clinical Pharmacology Unit, Ente Ospedaliero Ospedali Galliera, Genoa, Italy
| | - Antonella Riva
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
| | | | - Simona Lattanzi
- Neurological Clinic, Department of Experimental and Clinical Medicine, Marche Polytechnic University, Ancona, Italy
| | - Roberto Bandettini
- Chromatography and Mass Spectrometry Section, Central Laboratory of Analysis, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Pasquale Striano
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy; Paediatric Neurology and Muscular Disease Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Giuliana Cangemi
- Chromatography and Mass Spectrometry Section, Central Laboratory of Analysis, IRCCS Istituto Giannina Gaslini, Genoa, Italy
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Montanucci L, Brünger T, Bhattarai N, Boßelmann CM, Kim S, Allen JP, Zhang J, Klöckner C, Fariselli P, May P, Lemke JR, Myers SJ, Yuan H, Traynelis SF, Lal D. Distances from ligands as main predictive features for pathogenicity and functional effect of variants in NMDA receptors. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.05.06.24306939. [PMID: 38766179 PMCID: PMC11100844 DOI: 10.1101/2024.05.06.24306939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Genetic variants in genes GRIN1 , GRIN2A , GRIN2B , and GRIN2D , which encode subunits of the N-methyl-D-aspartate receptor (NMDAR), have been associated with severe and heterogeneous neurologic diseases. Missense variants in these genes can result in gain or loss of the NMDAR function, requiring opposite therapeutic treatments. Computational methods that predict pathogenicity and molecular functional effects are therefore crucial for accurate diagnosis and therapeutic applications. We assembled missense variants: 201 from patients, 631 from general population, and 159 characterized by electrophysiological readouts showing whether they can enhance or reduce the receptor function. This includes new functional data from 47 variants reported here, for the first time. We found that pathogenic/benign variants and variants that increase/decrease the channel function were distributed unevenly on the protein structure, with spatial proximity to ligands bound to the agonist and antagonist binding sites being key predictive features. Leveraging distances from ligands, we developed two independent machine learning-based predictors for NMDAR missense variants: a pathogenicity predictor which outperforms currently available predictors (AUC=0.945, MCC=0.726), and the first binary predictor of molecular function (increase or decrease) (AUC=0.809, MCC=0.523). Using these, we reclassified variants of uncertain significance in the ClinVar database and refined a previous genome-informed epidemiological model to estimate the birth incidence of molecular mechanism-defined GRIN disorders. Our findings demonstrate that distance from ligands is an important feature in NMDARs that can enhance variant pathogenicity prediction and enable functional prediction. Further studies with larger numbers of phenotypically and functionally characterized variants will enhance the potential clinical utility of this method.
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D'Onofrio G, Roberti R, Riva A, Russo E, Verrotti A, Striano P, Belcastro V. Pharmacodynamic rationale for the choice of antiseizure medications in the paediatric population. Neurotherapeutics 2024; 21:e00344. [PMID: 38521667 PMCID: PMC11070715 DOI: 10.1016/j.neurot.2024.e00344] [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: 11/27/2023] [Revised: 02/28/2024] [Accepted: 03/01/2024] [Indexed: 03/25/2024] Open
Abstract
In the landscape of paediatric epilepsy treatment, over 20 anti-seizure medications (ASMs) have gained approval from Drug Regulatory Agencies, each delineating clear indications. However, the complexity of managing drug-resistant epilepsy often necessitates the concurrent use of multiple medications. This therapeutic challenge highlights a notable gap: the absence of standardized guidelines, compelling clinicians to rely on empirical clinical experience when selecting combination therapies. This comprehensive review aims to explore current evidence elucidating the preferential utilization of specific ASMs or their combinations, with a primary emphasis on pharmacodynamic considerations. The fundamental objective underlying rational polytherapy is the strategic combination of medications, harnessing diverse mechanisms of action to optimize efficacy while mitigating shared side effects. Moreover, the intricate interplay between epilepsy and comorbidities partly may influence the treatment selection process. Despite advancements, unresolved queries persist, notably concerning the mechanisms underpinning drug resistance and the paradoxical exacerbation of seizures. By synthesizing existing evidence and addressing pertinent unresolved issues, this review aims to contribute to the evolving landscape of paediatric epilepsy treatment strategies, paving the way for more informed and efficacious therapeutic interventions.
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Affiliation(s)
- Gianluca D'Onofrio
- Department of Neurosciences Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DiNOGMI), University of Genoa, Via Gerolamo Gaslini 5, 16147 Genoa, Italy
| | - Roberta Roberti
- Science of Health Department, Magna Græcia University, Catanzaro, Italy
| | - Antonella Riva
- Department of Neurosciences Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DiNOGMI), University of Genoa, Via Gerolamo Gaslini 5, 16147 Genoa, Italy
| | - Emilio Russo
- Science of Health Department, Magna Græcia University, Catanzaro, Italy
| | | | - Pasquale Striano
- Department of Neurosciences Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DiNOGMI), University of Genoa, Via Gerolamo Gaslini 5, 16147 Genoa, Italy; Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto "Giannina Gaslini", Via Gerolamo Gaslini 5, 16147 Genoa, Italy
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Lersch R, Jannadi R, Grosse L, Wagner M, Schneider MF, von Stülpnagel C, Heinen F, Potschka H, Borggraefe I. Targeted Molecular Strategies for Genetic Neurodevelopmental Disorders: Emerging Lessons from Dravet Syndrome. Neuroscientist 2023; 29:732-750. [PMID: 35414300 PMCID: PMC10623613 DOI: 10.1177/10738584221088244] [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: 11/17/2022]
Abstract
Dravet syndrome is a severe developmental and epileptic encephalopathy mostly caused by heterozygous mutation of the SCN1A gene encoding the voltage-gated sodium channel α subunit Nav1.1. Multiple seizure types, cognitive deterioration, behavioral disturbances, ataxia, and sudden unexpected death associated with epilepsy are a hallmark of the disease. Recently approved antiseizure medications such as fenfluramine and cannabidiol have been shown to reduce seizure burden. However, patients with Dravet syndrome are still medically refractory in the majority of cases, and there is a high demand for new therapies aiming to improve behavioral and cognitive outcome. Drug-repurposing approaches for SCN1A-related Dravet syndrome are currently under investigation (i.e., lorcaserin, clemizole, and ataluren). New therapeutic concepts also arise from the field of precision medicine by upregulating functional SCN1A or by activating Nav1.1. These include antisense nucleotides directed against the nonproductive transcript of SCN1A with the poison exon 20N and against an inhibitory noncoding antisense RNA of SCN1A. Gene therapy approaches such as adeno-associated virus-based upregulation of SCN1A using a transcriptional activator (ETX101) or CRISPR/dCas technologies show promising results in preclinical studies. Although these new treatment concepts still need further clinical research, they offer great potential for precise and disease modifying treatment of Dravet syndrome.
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Affiliation(s)
- Robert Lersch
- Department of Pediatrics, Division of Pediatric Neurology, Developmental Medicine and Social Pediatrics, University Hospital of Munich, Ludwig Maximilians University, Munich, Germany
| | - Rawan Jannadi
- Department of Pediatrics, Division of Pediatric Neurology, Developmental Medicine and Social Pediatrics, University Hospital of Munich, Ludwig Maximilians University, Munich, Germany
- Institute of Human Genetics, University Hospital of Munich, Ludwig Maximilians University, Munich, Germany
| | - Leonie Grosse
- Department of Pediatrics, Division of Pediatric Neurology, Developmental Medicine and Social Pediatrics, University Hospital of Munich, Ludwig Maximilians University, Munich, Germany
| | - Matias Wagner
- Department of Pediatrics, Division of Pediatric Neurology, Developmental Medicine and Social Pediatrics, University Hospital of Munich, Ludwig Maximilians University, Munich, Germany
- Institute of Human Genetics, Technical University of Munich, Munich, Germany
- Institute for Neurogenomics, Helmholtz Centre Munich, German Research Center for Health and Environment (GmbH), Munich, Germany
| | - Marius Frederik Schneider
- Metabolic Biochemistry, Biomedical Center Munich, Medical Faculty, Ludwig Maximilians University, Munich, Germany
- International Max Planck Research School (IMPRS) for Molecular Life Sciences, Planegg-Martinsried, Germany
| | - Celina von Stülpnagel
- Department of Pediatrics, Division of Pediatric Neurology, Developmental Medicine and Social Pediatrics, University Hospital of Munich, Ludwig Maximilians University, Munich, Germany
- Research Institute for Rehabilitation, Transition and Palliation, Paracelsus Medical Private University (PMU), Salzburg, Austria
| | - Florian Heinen
- Department of Pediatrics, Division of Pediatric Neurology, Developmental Medicine and Social Pediatrics, University Hospital of Munich, Ludwig Maximilians University, Munich, Germany
| | - Heidrun Potschka
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig Maximilians University, Munich, Germany
| | - Ingo Borggraefe
- Department of Pediatrics, Division of Pediatric Neurology, Developmental Medicine and Social Pediatrics, University Hospital of Munich, Ludwig Maximilians University, Munich, Germany
- Comprehensive Epilepsy Center, University Hospital of Munich, Ludwig Maximilians University, Munich, Germany
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Borowicz-Reutt K, Czernia J, Krawczyk M. Genetic Background of Epilepsy and Antiepileptic Treatments. Int J Mol Sci 2023; 24:16280. [PMID: 38003469 PMCID: PMC10671416 DOI: 10.3390/ijms242216280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 11/01/2023] [Accepted: 11/08/2023] [Indexed: 11/26/2023] Open
Abstract
Advanced identification of the gene mutations causing epilepsy syndromes is expected to translate into faster diagnosis and more effective treatment of these conditions. Over the last 5 years, approximately 40 clinical trials on the treatment of genetic epilepsies have been conducted. As a result, some medications that are not regular antiseizure drugs (e.g., soticlestat, fenfluramine, or ganaxolone) have been introduced to the treatment of drug-resistant seizures in Dravet, Lennox-Gastaut, maternally inherited chromosome 15q11.2-q13.1 duplication (Dup 15q) syndromes, and protocadherin 19 (PCDH 19)-clusterig epilepsy. And although the effects of soticlestat, fenfluramine, and ganaxolone are described as promising, they do not significantly affect the course of the mentioned epilepsy syndromes. Importantly, each of these syndromes is related to mutations in several genes. On the other hand, several mutations can occur within one gene, and different gene variants may be manifested in different disease phenotypes. This complex pattern of inheritance contributes to rather poor genotype-phenotype correlations. Hence, the detection of a specific mutation is not synonymous with a precise diagnosis of a specific syndrome. Bearing in mind that seizures develop as a consequence of the predominance of excitatory over inhibitory processes, it seems reasonable that mutations in genes encoding sodium and potassium channels, as well as glutamatergic and gamma-aminobutyric (GABA) receptors, play a role in the pathogenesis of epilepsy. In some cases, different pathogenic variants of the same gene can result in opposite functional effects, determining the effectiveness of therapy with certain medications. For instance, seizures related to gain-of-function (GoF) mutations in genes encoding sodium channels can be successfully treated with sodium channel blockers. On the contrary, the same drugs may aggravate seizures related to loss-of-function (LoF) variants of the same genes. Hence, knowledge of gene mutation-treatment response relationships facilitates more favorable selection of drugs for anticonvulsant therapy.
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Affiliation(s)
- Kinga Borowicz-Reutt
- Independent Unit of Experimental Neuropathophysiology, Department of Toxicology, Medical University of Lublin, Jaczewskiego 8b, 20-090 Lublin, Poland; (J.C.); (M.K.)
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Dini G, Di Cara G, Ferrara P, Striano P, Verrotti A. Reintroducing Fenfluramine as a Treatment for Seizures: Current Knowledge, Recommendations and Gaps in Understanding. Neuropsychiatr Dis Treat 2023; 19:2013-2025. [PMID: 37790801 PMCID: PMC10543412 DOI: 10.2147/ndt.s417676] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 09/19/2023] [Indexed: 10/05/2023] Open
Abstract
Despite the introduction of new anti-seizure medications in recent years, approximately one-third of the epileptic population continues to experience seizures. Recently, the anti-obesity medication fenfluramine (FFA) has been successfully repurposed, and it has received approval from various regulatory agencies for the treatment of seizures associated with Dravet syndrome and Lennox-Gastaut syndrome. The potential antiseizure effects of FFA were initially observed in patients with photosensitive epilepsy in the 1980s but it was not rigorously explored as a treatment option until 30 years later. This narrative review aims to provide an overview of the historical progression of FFA's use, starting from initial clinical observations to preclinical studies and, ultimately, successful clinical trials in the field of epilepsy.
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Affiliation(s)
- Gianluca Dini
- Department of Pediatrics, University of Perugia, Perugia, Italy
| | | | - Pietro Ferrara
- Department of Pediatrics, Campus Bio-Medico University, Rome, Italy
| | - Pasquale Striano
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto “G. Gaslini”, Genoa, Italy
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Sills GJ. Pharmacological diversity amongst approved and emerging antiseizure medications for the treatment of developmental and epileptic encephalopathies. Ther Adv Neurol Disord 2023; 16:17562864231191000. [PMID: 37655228 PMCID: PMC10467199 DOI: 10.1177/17562864231191000] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 07/13/2023] [Indexed: 09/02/2023] Open
Abstract
Developmental and epileptic encephalopathies (DEEs) are rare neurodevelopmental disorders characterised by early-onset and often intractable seizures and developmental delay/regression, and include Dravet syndrome and Lennox-Gastaut syndrome (LGS). Rufinamide, fenfluramine, stiripentol, cannabidiol and ganaxolone are antiseizure medications (ASMs) with diverse mechanisms of action that have been approved for treating specific DEEs. Rufinamide is thought to suppress neuronal hyperexcitability by preventing the functional recycling of voltage-gated sodium channels from the inactivated to resting state. It is licensed for adjunctive treatment of seizures associated with LGS. Fenfluramine increases extracellular serotonin levels and may reduce seizures via activation of specific serotonin receptors and positive modulation of the sigma-1 receptor. Fenfluramine is licensed for adjunctive treatment of seizures associated with Dravet syndrome and LGS. Stiripentol is a positive allosteric modulator of type-A gamma-aminobutyric acid (GABAA) receptors. As a broad-spectrum inhibitor of cytochrome P450 enzymes, its antiseizure effects may additionally arise through pharmacokinetic interactions with co-administered ASMs. Stiripentol is licensed for treating seizures associated with Dravet syndrome in patients taking clobazam and/or valproate. The mechanism(s) of action of cannabidiol remains largely unclear although multiple targets have been proposed, including transient receptor potential vanilloid 1, G protein-coupled receptor 55 and equilibrative nucleoside transporter 1. Cannabidiol is licensed as adjunctive treatment in conjunction with clobazam for seizures associated with Dravet syndrome and LGS, and as adjunctive treatment of seizures associated with tuberous sclerosis complex. Like stiripentol, ganaxolone is a positive allosteric modulator at GABAA receptors. It has recently been licensed in the USA for the treatment of seizures associated with cyclin-dependent kinase-like 5 deficiency disorder. Greater understanding of the causes of DEEs has driven research into the potential use of other novel and repurposed agents. Putative ASMs currently in clinical development for use in DEEs include soticlestat, carisbamate, verapamil, radiprodil, clemizole and lorcaserin.
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Affiliation(s)
- Graeme J. Sills
- School of Life Sciences, University of Glasgow, Room 341, Sir James Black Building, Glasgow G12 8QQ, UK
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Sourbron J, Lagae L. Fenfluramine: a plethora of mechanisms? Front Pharmacol 2023; 14:1192022. [PMID: 37251322 PMCID: PMC10213522 DOI: 10.3389/fphar.2023.1192022] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 04/10/2023] [Indexed: 05/31/2023] Open
Abstract
Developmental and epileptic encephalopathies are rare, treatment-resistant epilepsies with high seizure burden and non-seizure comorbidities. The antiseizure medication (ASM) fenfluramine is an effective treatment for reducing seizure frequency, ameliorating comorbidities, and potentially reducing risk of sudden unexpected death in epilepsy (SUDEP) in patients with Dravet syndrome and Lennox-Gastaut syndrome, among other rare epilepsies. Fenfluramine has a unique mechanism of action (MOA) among ASMs. Its primary MOA is currently described as dual-action sigma-1 receptor and serotonergic activity; however, other mechanisms may be involved. Here, we conduct an extensive review of the literature to identify all previously described mechanisms for fenfluramine. We also consider how these mechanisms may play a role in the reports of clinical benefit in non-seizure outcomes, including SUDEP and everyday executive function. Our review highlights the importance of serotonin and sigma-1 receptor mechanisms in maintaining a balance between excitatory (glutamatergic) and inhibitory (γ-aminobutyric acid [GABA]-ergic) neural networks, and suggests that these mechanisms may represent primary pharmacological MOAs in seizures, non-seizure comorbidities, and SUDEP. We also describe ancillary roles for GABA neurotransmission, noradrenergic neurotransmission, and the endocrine system (especially such progesterone derivatives as neuroactive steroids). Dopaminergic activity underlies appetite reduction, a common side effect with fenfluramine treatment, but any involvement in seizure reduction remains speculative. Further research is underway to evaluate promising new biological pathways for fenfluramine. A better understanding of the pharmacological mechanisms for fenfluramine in reducing seizure burden and non-seizure comorbidities may allow for rational drug design and/or improved clinical decision-making when prescribing multi-ASM regimens.
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Efficacy and Safety of Fenfluramine in Epilepsy: A Systematic Review and Meta-analysis. Neurol Ther 2023; 12:669-686. [PMID: 36853503 PMCID: PMC10043095 DOI: 10.1007/s40120-023-00452-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Accepted: 02/07/2023] [Indexed: 03/01/2023] Open
Abstract
INTRODUCTION Fenfluramine (FFA) is an amphetamine derivative that promotes the release and blocks the neuronal reuptake of serotonin. Initially introduced as an appetite suppressant, FFA also showed antiseizure properties. This systematic review aimed to assess the efficacy and safety of FFA for the treatment of seizures in patients with epilepsy. METHODS We systematically searched (in week 3 of June 2022) MEDLINE, the Cochrane Central Register of Controlled Trials, and the US National Institutes of Health Clinical Trials Registry. Randomized, double- or single-blinded, placebo-controlled studies of FFA in patients with epilepsy and uncontrolled seizures were identified. Efficacy outcomes included the proportions of patients with ≥ 50% and 100% reductions in baseline seizure frequency during the treatment period. Tolerability outcomes included the proportions of patients who withdrew from treatment for any reason and suffered adverse events (AEs). The risk of bias in the included studies was assessed according to the recommendations of the Cochrane Handbook for Systematic Reviews of Interventions. The risk ratio (RR) along with the 95% confidence interval (CI) were estimated for each outcome. RESULTS Three trials were identified and a total of 469 Dravet syndrome (DS) and Lennox-Gastaut syndrome (LGS) subjects were randomized. All three trials were judged to be at low risk of biases. In patients with DS, the RRs for ≥ 50% and 100% reductions in convulsive seizure frequency for the FFA group compared to placebo were 5.61 (95% CI 2.73-11.54) and 4.71 (95% CI 0.57-39.30), respectively. In patients with LGS, the corresponding RRs for ≥ 50% and 100% reductions in drop seizure frequency were 2.58 (95% CI 1.33-5.02) and 0.50 (95% CI 0.031-7.81), respectively. The drug was withdrawn for any reason in 10.1% and 5.8% of patients receiving FFA and placebo, respectively (RR 1.79, 95% CI 0.89-3.59). Treatment discontinuation due to AEs occurred in 5.4% and 1.2% of FFA- and placebo-treated patients, respectively (RR 3.63, 95% CI 0.93-14.16). Decreased appetite, diarrhoea, fatigue, and weight loss were AEs associated with FFA treatment. CONCLUSION Fenfluramine reduces the frequency of seizures in patients with DS and LGS. Decreased appetite, diarrhoea, fatigue, and weight loss are non-cardiovascular AEs associated with FFA.
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Samanta D. Fenfluramine: A Review of Pharmacology, Clinical Efficacy, and Safety in Epilepsy. CHILDREN 2022; 9:children9081159. [PMID: 36010049 PMCID: PMC9406381 DOI: 10.3390/children9081159] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 07/30/2022] [Accepted: 08/01/2022] [Indexed: 11/29/2022]
Abstract
Despite the availability of more than 30 antiseizure medications (ASMs), the proportion of patients who remain refractory to ASMs remains static. Refractory seizures are almost universal in patients with epileptic encephalopathies. Since many of these patients are not candidates for curative surgery, there is always a need for newer ASMs with better efficacy and safety profile. Recently, the anti-obesity medication fenfluramine (FFA) has been successfully repurposed, and various regulatory agencies approved it for seizures associated with Dravet and Lennox–Gastaut syndromes. However, there is a limited in-depth critical review of FFA to facilitate its optimal use in a clinical context. This narrative review discusses and summarizes the antiseizure mechanism of action of FFA, clinical pharmacology, and clinical studies related to epilepsy, focusing on efficacy and adverse effects.
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Affiliation(s)
- Debopam Samanta
- Child Neurology Section, Department of Pediatrics, University of Arkansas for Medical Sciences, 1 Children's Way, Little Rock, AR 72202, USA
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Abstract
There are numerous potential factors that may affect growth in children with epilepsy, and these must be evaluated in any child with appetite and weight concerns. Antiseizure medications (ASMs) have potential adverse effects, and many may affect appetite, thus impacting normal growth and weight gain. The aim of this review is to focus on the impact of both epilepsy and ASMs on appetite and weight in children. We systematically reviewed studies using Medline assessing the impact of ASMs on appetite and weight in children. Eligible studies included randomized controlled trials and open-label studies (open-label extension and interventional) that targeted or included the pediatric population (0-18 years of age). Each study was classified using the American Academy of Neurology (AAN) Classification of Evidence for Therapeutic Studies, and the level of evidence for impact on appetite and weight in children was graded. ASMs associated with decreased appetite and/or weight loss include fenfluramine, topiramate, zonisamide, felbamate, rufinamide, stiripentol, cannabidiol, brivaracetam and ethosuximide; ASMs with minimal impact on weight and appetite in children include oxcarbazepine, eslicarbazepine, lamotrigine, levetiracetam, lacosamide, carbamazepine, vigabatrin and clobazam. The ASM most robustly associated with increased appetite and/or weight gain is valproic acid; however, both pregabalin and perampanel may also lead to modest weight gain or increased appetite in children. Certain ASMs may impact both appetite and weight, which may lead to increased morbidity of the underlying disease and impaired adherence to the treatment regimen.
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Varughese RT, Karkare S, Poduri A, Kothare SV. Child Neurology: Initial Presentation of PCDH19-Related Epilepsy with New Onset Refractory Status Epilepticus and Treatment with Anakinra. Neurology 2022; 99:208-211. [DOI: 10.1212/wnl.0000000000200855] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 04/29/2022] [Indexed: 11/15/2022] Open
Abstract
PCDH19-related epilepsy is a developmental and epileptic encephalopathy typically presenting with epilepsy and varying degrees of intellectual disability. Seizures typically present in clusters of focal or generalized seizures, sometimes in the setting of fever. We present the case of a 7-month-old girl presenting with new-onset refractory status epilepticus (NORSE) that followed routine vaccine administration and ensuing cytokine storm. She was diagnosed with a pathogenic variant in PCDH19. The patient required five anti-seizure medications and pentobarbital-induced burst suppression for control of seizures. She was noted to have elevated serum cytokine levels (IL-2, IL-4, IL-10, IL-13, IL-17, IL-1 IL-1β, and IL-8) and CSF cytokine levels (IL-6 and IL-13). Anakinra was initiated and titrated based on serial cytokine levels, with doses ranging from 5-20 mg/kg/day resulting in reduction in cytokine levels and seizure reduction. By 14 months of age, she was able to be maintained on three active anti-seizure medications and with ketogenic diet for seizure control.
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Vasquez A, Buraniqi E, Wirrell EC. New and emerging pharmacologic treatments for developmental and epileptic encephalopathies. Curr Opin Neurol 2022; 35:145-154. [PMID: 35102126 DOI: 10.1097/wco.0000000000001029] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW Summarize evidence on Developmental and Epileptic Encephalopathies (DEEs) treatments focusing on new and emerging pharmacologic therapies (see Video, http://links.lww.com/CONR/A61, Supplementary Digital Content 1, which provides an overview of the review). RECENT FINDINGS Advances in the fields of molecular genetics and neurobiology have led to the recognition of underlying pathophysiologic mechanisms involved in an increasing number of DEEs that could be targeted with precision therapies or repurposed drugs, some of which are currently being evaluated in clinical trials. Prompt, optimal therapy is critical, and promising therapies approved or in clinical trials for tuberous sclerosis complex, Dravet and Lennox-Gastaut Syndromes including mammalian target of rapamycin inhibitors, selective membrane channel and antisense oligonucleotide modulation, and repurposed drugs such as fenfluramine, stiripentol and cannabidiol, among others, may improve seizure burden and neurological outcomes. There is an urgent need for collaborative efforts to evaluate the efficacy and safety of emerging DEEs therapies. SUMMARY Development of new therapies promise to address unmet needs for patients with DEEs, including improvement of neurocognitive function and quality of life.
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Affiliation(s)
- Alejandra Vasquez
- Division of Child and Adolescent Neurology, Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA
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14
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Bialer M, Perucca E. Lorcaserin for Dravet Syndrome: A Potential Advance Over Fenfluramine? CNS Drugs 2022; 36:113-122. [PMID: 35094259 DOI: 10.1007/s40263-022-00896-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/09/2022] [Indexed: 12/12/2022]
Abstract
Lorcaserin, a selective serotonin 5-HT2C receptor agonist, was developed as an appetite suppressant with the rationale of minimizing the risk of cardiovascular toxicity associated with non-selective serotoninergic agents such as fenfluramine. Eight years after FDA approval, however, it was withdrawn from the market, when a large safety study suggested a potential cancer risk. Following in the fenfluramine footsteps and utilizing the repurposing approach coupled with the regulatory orphan drug designation, lorcaserin is currently in clinical development for the treatment of epilepsy. This potential novel indication builds on the evidence that 5-HT2C receptor stimulation can protect against seizures, and accounts at least in part for fenfluramine's antiseizure effects in Dravet syndrome models. In animal models, lorcaserin shows a narrower range of antiseizure activity than fenfluramine. In particular, lorcaserin is inactive in classical acute seizure tests such as maximal electroshock and subcutaneous pentylenetetrazole in mice and rats, and the 6-Hz stimulation model in mice. However, it is active in the GAERS absence seizure model, and in mutant zebrafish models of Dravet syndrome. Preliminary uncontrolled studies in patients with Dravet syndrome have yielded promising results, and a phase III, double-blind, placebo-controlled, parallel group trial is currently ongoing to assess its efficacy and safety in children and adults with Dravet syndrome.
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Affiliation(s)
- Meir Bialer
- Institute of Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel. .,David R. Bloom Center for Pharmacy, The Hebrew University of Jerusalem, Jerusalem, Israel.
| | - Emilio Perucca
- Department of Medicine, Austin Health, University of Melbourne, Melbourne, VIC, Australia.,Department of Neuroscience, Monash University, Melbourne, VIC, Australia
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15
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Sourbron J, Lagae L. Serotonin receptors in epilepsy: novel treatment targets? Epilepsia Open 2022; 7:231-246. [PMID: 35075810 PMCID: PMC9159250 DOI: 10.1002/epi4.12580] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 01/08/2022] [Accepted: 01/20/2022] [Indexed: 11/24/2022] Open
Abstract
Despite the availability of over 30 antiseizure medications (ASMs), there is no “one size fits it all,” so there is a continuing search for novel ASMs. There are divergent data demonstrating that modulation of distinct serotonin (5‐hydroxytryptamine, 5‐HT) receptors subtypes could be beneficial in the treatment of epilepsy and its comorbidities, whereas only a few ASM, such as fenfluramine (FA), act via 5‐HT. There are 14 different 5‐HT receptor subtypes, and most epilepsy studies focus on one or a few of these subtypes, using different animal models and different ligands. We reviewed the available evidence of each 5‐HT receptor subtype using MEDLINE up to July 2021. Our search included medical subject heading (MeSH) and free terms of each “5‐HT subtype” separately and its relation to “epilepsy or seizures.” Most research underlines the antiseizure activity of 5‐HT1A,1D,2A,2C,3 agonism and 5‐HT6 antagonism. Consistently, FA, which has recently been approved for the treatment of seizures in Dravet syndrome, is an agonist of 5‐HT1D,2A,2C receptors. Even though each study focused on a distinct seizure/epilepsy type and generalization of different findings could lead to false interpretations, we believe that the available preclinical and clinical studies emphasize the role of serotonergic modulation, especially stimulation, as a promising avenue in epilepsy treatment.
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Affiliation(s)
- Jo Sourbron
- Department of Development and Regeneration, Section Pediatric Neurology, University Hospital KU Leuven, Leuven, Belgium.,Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium
| | - Lieven Lagae
- Department of Development and Regeneration, Section Pediatric Neurology, University Hospital KU Leuven, Leuven, Belgium
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16
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Schoonjans AS, Roosens L, Dewals W, Paelinck BP, Ceulemans B. Therapeutic drug monitoring of fenfluramine in clinical practice: Pharmacokinetic variability and impact of concomitant antiseizure medications. Epilepsia 2022; 63:686-696. [PMID: 35032026 DOI: 10.1111/epi.17162] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 12/23/2021] [Accepted: 12/23/2021] [Indexed: 11/30/2022]
Abstract
OBJECTIVE This study was undertaken to determine the plasma concentration and pharmacokinetic variability of fenfluramine (FFA) and its main active metabolite norfenfluramine (norFFA) in relation to the prevalence of adverse effects in patients with refractory epilepsy treated with FFA. In addition, the interaction with concomitant antiseizure medications including stiripentol (STP) is studied. METHODS Patients were recruited at our center from two open-label sources, an investigator-initiated observational study and an international multicenter extension study. Venous blood samples were collected between June 2015 and December 2020. Plasma FFA and norFFA concentrations were determined by liquid chromatography tandem spectrometric analysis. Clinical data were collected retrospectively. Intrapatient coefficient of variation was calculated for all patients with at least three samples. Interpatient variability was calculated based on the concentration to weight-adjusted dose ratio (C/D) of all patients. RESULTS We collected 321 samples from 61 patients (49 with Dravet syndrome, seven with Lennox-Gastaut syndrome, and five with a developmental and epileptic encephalopathy). With a mean daily dose of .33 mg/kg/day (SD = ±.16), the median FFA plasma concentration was 41.4 µg/L (range = 5.1-712.5) and median norFFA concentration 28.1 µg/L (range = 2.6-149.6). The FFA plasma concentration was linearly related to the daily dose (p < .001) and norFFA levels (p < .001). The C/D of FFA increased with age (p < .001). Median FFA C/D was 428% higher (p < .001), norFFA C/D 83% lower (p < .001), and norFFA/FFA 23% lower (p < .001) in patients treated with STP comedication. Higher FFA concentration was associated with fatigue (p = .001) and somnolence (p < .001), but not anorexia (p = .0619) or reduction in seizure frequency (p = .772). Gender and other ASMs were not associated with significant variations in (nor)FFA C/D ratio. SIGNIFICANCE Most FFA levels are in the lower range (<50 µg/L), although a high interpatient and intrapatient variability is present. In combination with STP, the dose of FFA should be reduced.
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Affiliation(s)
- An-Sofie Schoonjans
- Department of Pediatrics, Antwerp University Hospital, Edegem, Belgium.,University of Antwerp, Antwerp, Belgium
| | - Laurence Roosens
- University of Antwerp, Antwerp, Belgium.,Laboratory for TDM and Toxicology, Antwerp University Hospital, Edegem, Belgium
| | - Wendy Dewals
- Department of Pediatrics, Antwerp University Hospital, Edegem, Belgium
| | | | - Berten Ceulemans
- Department of Pediatrics, Antwerp University Hospital, Edegem, Belgium.,University of Antwerp, Antwerp, Belgium
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Crouzier L, Richard EM, Sourbron J, Lagae L, Maurice T, Delprat B. Use of Zebrafish Models to Boost Research in Rare Genetic Diseases. Int J Mol Sci 2021; 22:13356. [PMID: 34948153 PMCID: PMC8706563 DOI: 10.3390/ijms222413356] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 12/09/2021] [Accepted: 12/10/2021] [Indexed: 02/06/2023] Open
Abstract
Rare genetic diseases are a group of pathologies with often unmet clinical needs. Even if rare by a single genetic disease (from 1/2000 to 1/more than 1,000,000), the total number of patients concerned account for approximatively 400 million peoples worldwide. Finding treatments remains challenging due to the complexity of these diseases, the small number of patients and the challenge in conducting clinical trials. Therefore, innovative preclinical research strategies are required. The zebrafish has emerged as a powerful animal model for investigating rare diseases. Zebrafish combines conserved vertebrate characteristics with high rate of breeding, limited housing requirements and low costs. More than 84% of human genes responsible for diseases present an orthologue, suggesting that the majority of genetic diseases could be modelized in zebrafish. In this review, we emphasize the unique advantages of zebrafish models over other in vivo models, particularly underlining the high throughput phenotypic capacity for therapeutic screening. We briefly introduce how the generation of zebrafish transgenic lines by gene-modulating technologies can be used to model rare genetic diseases. Then, we describe how zebrafish could be phenotyped using state-of-the-art technologies. Two prototypic examples of rare diseases illustrate how zebrafish models could play a critical role in deciphering the underlying mechanisms of rare genetic diseases and their use to identify innovative therapeutic solutions.
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Affiliation(s)
- Lucie Crouzier
- MMDN, University of Montpellier, EPHE, INSERM, 34095 Montpellier, France; (L.C.); (E.M.R.); (T.M.)
| | - Elodie M. Richard
- MMDN, University of Montpellier, EPHE, INSERM, 34095 Montpellier, France; (L.C.); (E.M.R.); (T.M.)
| | - Jo Sourbron
- Department of Development and Regeneration, Section Pediatric Neurology, University Hospital KU Leuven, 3000 Leuven, Belgium; (J.S.); (L.L.)
| | - Lieven Lagae
- Department of Development and Regeneration, Section Pediatric Neurology, University Hospital KU Leuven, 3000 Leuven, Belgium; (J.S.); (L.L.)
| | - Tangui Maurice
- MMDN, University of Montpellier, EPHE, INSERM, 34095 Montpellier, France; (L.C.); (E.M.R.); (T.M.)
| | - Benjamin Delprat
- MMDN, University of Montpellier, EPHE, INSERM, 34095 Montpellier, France; (L.C.); (E.M.R.); (T.M.)
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18
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Tupal S, Faingold CL. Serotonin 5-HT 4 receptors play a critical role in the action of fenfluramine to block seizure-induced sudden death in a mouse model of SUDEP. Epilepsy Res 2021; 177:106777. [PMID: 34601387 DOI: 10.1016/j.eplepsyres.2021.106777] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 08/25/2021] [Accepted: 09/21/2021] [Indexed: 11/28/2022]
Abstract
RATIONALE Our previous study showed that the recently approved anticonvulsant drug, fenfluramine, which enhances the release of serotonin (5-hydroxytryptamine, 5-HT) in the brain, prevents seizure-induced respiratory arrest (S-IRA) in the DBA/1 mouse model of sudden unexpected death in epilepsy (SUDEP). The present study examined the role of 5-HT receptor subtypes in mediating the effect of this agent by combined administration of fenfluramine with selective 5-HT receptor antagonists prior to seizure in DBA/1 mice. METHODS Fenfluramine (15 mg/kg, i.p.) was administered to primed DBA/1 mice, and audiogenic seizure (Sz) was induced 16 h later. Thirty min prior to Sz induction a selective antagonist acting on 5-HT1A, 5-HT2, 5-HT3 5-HT4, 5-HT5A, 5-HT6 or 5-HT7 receptors at a sub-toxic dose was administered, and changes in seizure-induced behaviors were evaluated. Follow-up studies examined the effect of administration of a 5-HT4 receptor agonist, BIMU 8, as well as the effect of co-administration of ineffective doses of fenfluramine and BIMU-8 on Sz behaviors. RESULTS The 5-HT4 antagonist (GR125487) was the only 5-HT receptor antagonist that was able to reverse the action of fenfluramine to block Sz and S-IRA. Treatment with the 5-HT4 receptor agonist (BIMU-8), or co-administration of ineffective doses of BIMU-8 and fenfluramine significantly reduced the incidence of S-IRA and tonic Sz in DBA/1 mice. The antagonists for 5-HT3, 5-HT5A 5-HT6, and 5-HT7 receptors did not significantly affect the action of fenfluramine. However, the 5-HT1A and the 5-HT2 antagonists enhanced the anticonvulsant effects of fenfluramine. CONCLUSIONS These findings suggest that the action of fenfluramine to prevent seizure-induced sudden death in DBA/1 mice is mediated primarily by activation of 5-HT4 receptors. These studies are the first to indicate the therapeutic potential of 5-HT4 receptor agonists either alone or in combination with fenfluramine for preventing SUDEP. Enhancement of the anticonvulsant effect of fenfluramine by 5-HT1A and 5-HT2 antagonists may involve presynaptic actions of these antagonists. Thus, the Sz and S-IRA blocking actions of fenfluramine involve complex interactions with several 5-HT receptor subtypes. These data also provide further support for the serotonin hypothesis of SUDEP.
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Affiliation(s)
- Srinivasan Tupal
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - Carl L Faingold
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, USA.
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19
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Myers KA, Scheffer IE. Precision Medicine Approaches for Infantile-Onset Developmental and Epileptic Encephalopathies. Annu Rev Pharmacol Toxicol 2021; 62:641-662. [PMID: 34579535 DOI: 10.1146/annurev-pharmtox-052120-084449] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Epilepsy is an etiologically heterogeneous condition; however, genetic factors are thought to play a role in most patients. For those with infantile-onset developmental and epileptic encephalopathy (DEE), a genetic diagnosis is now obtained in more than 50% of patients. There is considerable motivation to utilize these molecular diagnostic data to help guide treatment, as children with DEEs often have drug-resistant seizures as well as developmental impairment related to cerebral epileptiform activity. Precision medicine approaches have the potential to dramatically improve the quality of life for these children and their families. At present, treatment can be targeted for patients with diagnoses in many genetic causes of infantile-onset DEE, including genes encoding sodium or potassium channel subunits, tuberous sclerosis, and congenital metabolic diseases. Precision medicine may refer to more intelligent choices of conventional antiseizure medications, repurposed agents previously used for other indications, novel compounds, enzyme replacement, or gene therapy approaches. Expected final online publication date for the Annual Review of Pharmacology and Toxicology, Volume 62 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Kenneth A Myers
- Research Institute of the McGill University Health Centre, Division of Child Neurology, Department of Pediatrics, and Department of Neurology and Neurosurgery, Montreal Children's Hospital, McGill University, Montreal, Quebec H4A 3J1, Canada;
| | - Ingrid E Scheffer
- Epilepsy Research Centre, Department of Medicine, The University of Melbourne, Austin Health, Heidelberg, Victoria 3084, Australia; .,Department of Paediatrics, Royal Children's Hospital, The University of Melbourne, Parkville, Victoria 3052, Australia.,The Florey Institute of Neuroscience and Mental Health and Murdoch Children's Research Institute, Parkville, Victoria 3052, Australia
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20
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Gogou M, Cross JH. Fenfluramine as antiseizure medication for epilepsy. Dev Med Child Neurol 2021; 63:899-907. [PMID: 33565102 DOI: 10.1111/dmcn.14822] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/05/2021] [Indexed: 12/11/2022]
Abstract
Fenfluramine hydrochloride has classically been described as acting pharmacologically through a serotonergic mechanism. Therefore, it was initially used as an anorectic drug, given that impaired serotonin homeostasis may be associated with increased food intake. Although positive results were documented, cardiovascular concerns resulted in its temporary withdrawal. Nevertheless, a novel role in patients with epilepsy was later suggested by isolated clinical observations. The wide application of genetic testing allowed the classification (predominantly as Dravet syndrome) of patients in whom benefit was seen, while with the development of zebrafish models, its antiepileptic properties were confirmed at a molecular level. Data from randomized clinical trials have shown a beneficial effect of fenfluramine, as an adjunct therapy, on seizure control for children with Dravet syndrome, though there is still uncertainty about the impact on neurodevelopment in these patients. No signs of heart valve disease have been documented to date. Long-term and appropriately designed clinical studies will verify whether fenfluramine is a therapeutic agent of high importance, living up to the promise shown so far. What this paper adds Fenfluramine is a very promising repurposed therapy specifically for seizures in Dravet syndrome. The long-term effect of fenfluramine on neurodevelopmental prognosis requires further investigation.
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Affiliation(s)
- Maria Gogou
- Department of Neurology, Great Ormond Street Hospital for Children NHS Trust, London, UK
| | - J Helen Cross
- Department of Neurology, Great Ormond Street Hospital for Children NHS Trust, London, UK.,Developmental Neurosciences, University College London NIHR BRC Great Ormond Street Institute of Child Health, London, UK
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21
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Fattorusso A, Matricardi S, Mencaroni E, Dell'Isola GB, Di Cara G, Striano P, Verrotti A. The Pharmacoresistant Epilepsy: An Overview on Existent and New Emerging Therapies. Front Neurol 2021; 12:674483. [PMID: 34239494 PMCID: PMC8258148 DOI: 10.3389/fneur.2021.674483] [Citation(s) in RCA: 94] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 05/27/2021] [Indexed: 12/21/2022] Open
Abstract
Epilepsy is one of the most common neurological chronic disorders, with an estimated prevalence of 0. 5 - 1%. Currently, treatment options for epilepsy are predominantly based on the administration of symptomatic therapy. Most patients are able to achieve seizure freedom by the first two appropriate drug trials. Thus, patients who cannot reach a satisfactory response after that are defined as pharmacoresistant. However, despite the availability of more than 20 antiseizure medications (ASMs), about one-third of epilepsies remain drug-resistant. The heterogeneity of seizures and epilepsies, the coexistence of comorbidities, and the broad spectrum of efficacy, safety, and tolerability related to the ASMs, make the management of these patients actually challenging. In this review, we analyze the most relevant clinical and pathogenetic issues related to drug-resistant epilepsy, and then we discuss the current evidence about the use of available ASMs and the alternative non-pharmacological approaches.
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Affiliation(s)
- Antonella Fattorusso
- Department of Medicine and Surgery, Pediatric Clinic, University of Perugia, Perugia, Italy
| | - Sara Matricardi
- Child Neurology and Psychiatry Unit, Children's Hospital “G. Salesi”, Ospedali Riuniti Ancona, Ancona, Italy
| | - Elisabetta Mencaroni
- Department of Medicine and Surgery, Pediatric Clinic, University of Perugia, Perugia, Italy
| | | | - Giuseppe Di Cara
- Department of Medicine and Surgery, Pediatric Clinic, University of Perugia, Perugia, Italy
| | - Pasquale Striano
- Pediatric Neurology and Muscular Diseases Unit, IRCCS “G. Gaslini” Institute, Genoa, Italy
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
| | - Alberto Verrotti
- Department of Medicine and Surgery, Pediatric Clinic, University of Perugia, Perugia, Italy
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22
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Odi R, Invernizzi RW, Gallily T, Bialer M, Perucca E. Fenfluramine repurposing from weight loss to epilepsy: What we do and do not know. Pharmacol Ther 2021; 226:107866. [PMID: 33895186 DOI: 10.1016/j.pharmthera.2021.107866] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 03/26/2021] [Accepted: 04/12/2021] [Indexed: 12/21/2022]
Abstract
In 2020, racemic-fenfluramine was approved in the U.S. and Europe for the treatment of seizures associated with Dravet syndrome, through a restricted/controlled access program aimed at minimizing safety risks. Fenfluramine had been used extensively in the past as an appetite suppressant, but it was withdrawn from the market in 1997 when it was found to cause cardiac valvulopathy. Available evidence indicates that appetite suppression and cardiac valvulopathy are mediated by different serotonergic mechanisms. In particular, appetite suppression can be ascribed mainly to the enantiomers d-fenfluramine and d-norfenfluramine, the primary metabolite of d-fenfluramine, whereas cardiac valvulopathy can be ascribed mainly to d-norfenfluramine. Because of early observations of markedly improved seizure control in some forms of epilepsy, fenfluramine remained available in Belgium through a Royal Decree after 1997 for use in a clinical trial in patients with Dravet syndrome at average dosages lower than those generally prescribed for appetite suppression. More recently, double-blind placebo-controlled trials established its efficacy in the treatment of convulsive seizures associated with Dravet syndrome and of drop seizures associated with Lennox-Gastaut syndrome, at doses up to 0.7 mg/kg/day (maximum 26 mg/day). Although no cardiovascular toxicity has been associated with the use of fenfluramine in epilepsy, the number of patients exposed to date has been limited and only few patients had duration of exposure longer than 3 years. This article analyzes available evidence on the mechanisms involved in fenfluramine-induced appetite suppression, antiseizure effects and cardiovascular toxicity. Despite evidence that stimulation of 5-HT2B receptors (the main mechanism leading to cardiac valvulopathy) is not required for antiseizure activity, there are many critical gaps in understanding fenfluramine's properties which are relevant to its use in epilepsy. Particular emphasis is placed on the remarkable lack of publicly accessible information about the comparative activity of the individual enantiomers of fenfluramine and norfenfluramine in experimental models of seizures and epilepsy, and on receptors systems considered to be involved in antiseizure effects. Preliminary data suggest that l-fenfluramine retains prominent antiseizure effects in a genetic zebrafish model of Dravet syndrome. If these findings are confirmed and extended to other seizure/epilepsy models, there would be an incentive for a chiral switch from racemic-fenfluramine to l-fenfluramine, which could minimize the risk of cardiovascular toxicity and reduce the incidence of adverse effects such as loss of appetite and weight loss.
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Affiliation(s)
- Reem Odi
- Institute of Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | | | - Tamar Gallily
- Yissum Technology Transfer Company of the Hebrew University of Jerusalem, Jerusalem, Israel
| | - Meir Bialer
- Institute of Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel; David R. Bloom Center for Pharmacy, The Hebrew University of Jerusalem, Jerusalem, Israel.
| | - Emilio Perucca
- Division of Clinical and Experimental Pharmacology, Department of Internal Medicine and Therapeutics, University of Pavia, Pavia, Italy
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Sullo F, Pasquetti E, Patanè F, Lo Bianco M, Marino SD, Polizzi A, Falsaperla R, Ruggieri M, Zanghì A, Praticò AD. SCN1A and Its Related Epileptic Phenotypes. JOURNAL OF PEDIATRIC NEUROLOGY 2021. [DOI: 10.1055/s-0041-1727260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
AbstractEpilepsy is one of the most common neurological disorders, with a lifetime incidence of 1 in 26. Approximately two-thirds of epilepsy has a substantial genetic component in its etiology. As a result, simultaneous screening for mutations in multiple genes and performing whole exome sequencing (WES) are becoming very frequent in the clinical evaluation of children with epilepsy. In this setting, mutations in voltage-gated sodium channel (SCN) α-subunit genes are the most commonly identified cause of epilepsy, with sodium channel genes (i.e., SCN1A, SCN2A, SCN8A) being the most frequently identified causative genes. SCN1A mutations result in a wide spectrum of epilepsy phenotypes ranging from simple febrile seizures to Dravet syndrome, a severe epileptic encephalopathy. In case of mutation of SCN1A, it is also possible to observe behavioral alterations, such as impulsivity, inattentiveness, and distractibility, which can be framed in an attention deficit hyperactivity disorder (ADHD) like phenotype. Despite more than 1,200 SCN1A mutations being reported, it is not possible to assess a clear phenotype–genotype correlations. Treatment remains a challenge and seizure control is often partial and transitory.
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Affiliation(s)
- Federica Sullo
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Elisa Pasquetti
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Francesca Patanè
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Manuela Lo Bianco
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Simona D. Marino
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
| | - Agata Polizzi
- Chair of Pediatrics, Department of Educational Sciences, University of Catania, Catania, Italy
| | - Raffaele Falsaperla
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
- Unit of Neonatal Intensive Care and Neonatology, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
| | - Martino Ruggieri
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Antonio Zanghì
- Department of Medical and Surgical Sciences and Advanced Technology “G.F. Ingrassia,” University of Catania, Catania, Italy
| | - Andrea D. Praticò
- Unit of Rare Diseases of the Nervous System in Childhood, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
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24
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Schoonjans AS, Ceulemans B. A critical evaluation of fenfluramine hydrochloride for the treatment of Dravet syndrome. Expert Rev Neurother 2021; 22:351-364. [PMID: 33455486 DOI: 10.1080/14737175.2021.1877540] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Introduction: Dravet Syndrome (DS) is a severe developmental and epileptic encephalopathy. Fenfluramine recently demonstrated to be a highly efficacious and safe treatment option for DS patients. Fenfluramine has been recently approved by the FDA and EMA and is marketed as Fintepla®.Areas covered: DS and the need for additional anticonvulsive treatment options is discussed. The results of three placebo-controlled phase III studies (1 with and 2 without stiripentol) and 2 open label (extension) studies are reviewed. All studies demonstrate a consistent and impressive seizure reduction, confirming the results of two smaller investigator-initiated trials. The mechanism of action of fenfluramine is discussed. Finally, the place of fenfluramine in the future treatment of DS is outlined.Expert opinion: Fenfluramine has a potent anticonvulsive effect in DS. Although not yet fully elucidated, the anticonvulsive mechanism of fenfluramine seems to be mainly serotonergic. Fenfluramine is generally well tolerated. A dose reduction is necessary in combination with stiripentol. Considering new competitors, efficacy seems lower for cannabidiol and is comparable with stiripentol. Preclinical studies indicate a disease specific action and possible disease modification in DS. The latter would support the use of fenfluramine above its anticonvulsive effect and needs to be further elaborated.
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Affiliation(s)
- An-Sofie Schoonjans
- Department of Pediatrics and Pediatric Neurology, Antwerp University Hospital, Edegem, Belgium.,Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Berten Ceulemans
- Department of Pediatrics and Pediatric Neurology, Antwerp University Hospital, Edegem, Belgium.,Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
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25
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Sharawat IK, Panda PK, Kasinathan A, Panda P, Dawman L, Joshi K. Efficacy and tolerability of fenfluramine in patients with Dravet syndrome: A systematic review and meta-analysis. Seizure 2021; 85:119-126. [DOI: 10.1016/j.seizure.2020.12.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 12/27/2020] [Accepted: 12/29/2020] [Indexed: 12/13/2022] Open
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26
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Verrotti A, Striano P. Novel therapeutic options for Dravet and Lennox-Gastaut syndrome. Expert Rev Neurother 2021; 21:1191-1194. [PMID: 33297778 DOI: 10.1080/14737175.2020.1862651] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
| | - Pasquale Striano
- Pediatric Neurology and Muscular Diseases Unit, IRRCS Istituto Giannina Gaslini, Genova, Italy.,Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, Università Degli Studi di Genova, Genova, Italy
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27
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Miziak B, Czuczwar S. Advances in the design and discovery of novel small molecule drugs for the treatment of Dravet Syndrome. Expert Opin Drug Discov 2020; 16:579-593. [PMID: 33275464 DOI: 10.1080/17460441.2021.1857722] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Introduction: Dravet syndrome (severe myoclonic epilepsy in infancy) begins in the first year of life characterized by generalized or unilateral clonic seizures that are frequently triggered by high fever. A subsequent worsening stage occurs (in years 1-4 of life) and seizure activity is accompanied by disturbed psychomotor development. The third stage of the disease, known as the 'stabilization phase,' is associated with seizures and intellectual impairment. Of note, a mutation in the voltage-gated sodium-channel gene α 1 subunit (SCN1A) has been found in around 85% of patients with Dravet syndrome.Areas covered: The authors review the current treatment strategies as well as potential drugs in the initial stages of clinical evaluation. The authors also review drugs with protective activity in mice models of Dravet syndrome.Expert opinion: Experimental data and results from initial clinical studies have brought attention to several drugs with various mechanisms of action including: ataluren (a suppressant of premature stop codons; under clinical evaluation), EPX-100, EPX-200, fenfluramine (serotonin modulators), soticlestat (an 24-hydroxylase cholesterol enzyme inhibitor), SPN-817 (an inhibitor of acetylcholinesterase), verapamil (a voltage-dependent calcium channel inhibitor) and STK-001 (an antisense oligonucleotide). The latter is scheduled for clinical evaluation.
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Affiliation(s)
- Barbara Miziak
- Department of Pathophysiology, Medical University of Lublin, Lublin, Poland
| | - Stanisław Czuczwar
- Department of Pathophysiology, Medical University of Lublin, Lublin, Poland
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28
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Mucke HA. Drug Repurposing Patent Applications April–June 2020. Assay Drug Dev Technol 2020; 18:385-390. [DOI: 10.1089/adt.2020.1019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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29
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Sullivan J, Scheffer IE, Lagae L, Nabbout R, Pringsheim M, Talwar D, Polster T, Galer B, Lock M, Agarwal A, Gammaitoni A, Morrison G, Farfel G. Fenfluramine HCl (Fintepla ® ) provides long-term clinically meaningful reduction in seizure frequency: Analysis of an ongoing open-label extension study. Epilepsia 2020; 61:2396-2404. [PMID: 33078386 PMCID: PMC7756901 DOI: 10.1111/epi.16722] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 09/18/2020] [Accepted: 09/22/2020] [Indexed: 01/15/2023]
Abstract
OBJECTIVE Fenfluramine has been shown to provide clinically meaningful and statistically significant reductions in convulsive seizure frequency in children and adolescents (aged 2-18 years) with Dravet syndrome in two randomized, placebo-controlled clinical trials. The objective of this analysis was to assess longer-term safety and efficacy of fenfluramine in patients who completed one of the double-blind studies and entered an open-label extension (OLE) study. METHODS Patients enrolling in the OLE study initiated fenfluramine at 0.2 mg/kg/d regardless of their treatment assignment in the double-blind study. After 4 weeks, the fenfluramine dose could be titrated based on efficacy and tolerability to maximum of 0.7 mg/kg/d (absolute maximum 27 mg/d) or maximum of 0.4 mg/kg/d (absolute maximum 17 mg/d) in patients receiving concomitant stiripentol. The number and type of seizures were recorded daily in an electronic diary, and safety, including echocardiography, was assessed at Months 1, 2, and 3, and at 3-month intervals thereafter. RESULTS A total of 232 patients were enrolled as of March 13, 2018. During this analysis period, patients were treated for a median 256 days (range = 46-634 days). Over the entire OLE analysis period, the median decrease in convulsive seizure frequency compared to baseline in the double-blind studies was -66.8% (range = -100% to 234.9%; P < .001). The median reduction in seizure frequency was similar in patients <6 (-75.7%) and ≥6 years old (-64.7%). The most commonly reported adverse events included pyrexia (21.6%), nasopharyngitis (19.4%), and decreased appetite (-15.9%). No valvular heart disease (VHD) or pulmonary arterial hypertension (PAH) was observed. SIGNIFICANCE Study results demonstrate that fenfluramine provides clinically meaningful (≥50%) seizure frequency reduction over an extended period in patients with Dravet syndrome. No patient developed VHD or PAH, and fenfluramine was generally well tolerated.
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Affiliation(s)
- Joseph Sullivan
- Benioff Children's Hospital, University of California San Francisco, San Francisco, CA, USA
| | - Ingrid E Scheffer
- Austin Health and Royal Children's Hospital, University of Melbourne, Melbourne, VIC, Australia
| | - Lieven Lagae
- Department of Paediatric Neurology, University of Leuven, Leuven, Belgium
| | - Rima Nabbout
- Service de Neurologie Pédiatrique Centre de Référence Épilepsies Rares (CReER), Hôpital Universitaire Necker - Enfants Malades, Paris, France
| | - Milka Pringsheim
- Department of Pediatric Cardiology, German Heart Centre Munich, Munich, Germany.,Pediatric Neurology, Schön Klinik Vogtareuth, Vogtareuth, Germany
| | - Dinesh Talwar
- Center for Neurosciences, University of Arizona Health Sciences Center, Tucson, AZ, USA
| | - Tilman Polster
- Department of Pediatric Epileptology, Bethel Epilepsy Center, Mara Hospital, Bielefeld, Germany
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30
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Balagura G, Cacciatore M, Grasso EA, Striano P, Verrotti A. Fenfluramine for the Treatment of Dravet Syndrome and Lennox-Gastaut Syndrome. CNS Drugs 2020; 34:1001-1007. [PMID: 32875491 DOI: 10.1007/s40263-020-00755-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The last 50 years has seen the introduction of a great number of antiepileptic drugs, relieving the burden of seizures for many patients. However, some conditions remain a challenge for epileptologists, especially Dravet syndrome and Lennox-Gastaut syndrome, which are severe epileptic and developmental encephalopathies characterized by multiple seizure types and electroencephalographic abnormalities that are often unresponsive to combinations of antiepileptic drugs. The re-purposing of an old drug such as fenfluramine could provide an indispensable tool for clinicians, especially because only a few drugs have been tested in relatively homogeneous populations, like Dravet syndrome. It could also provide insights into precision medicine approaches to the treatment of epileptic syndromes. We searched for relevant papers within MEDLINE, EMBASE, and the Clinical Trial Database, considering publications through July 2020. Pre-clinical studies show a mechanism of action for fenfluramine that goes beyond its pro-serotoninergic activity and that is at the intersection of several pathways involved in excitation/inhibition balance. From the ongoing clinical trial data, it is evident that fenfluramine is proving to be a promising antiepileptic drug with very favorable pharmacokinetics and with a good overall safety profile when used at a lower dosage (0.2-0.7 mg/kg/day), despite its previously link to major cardiac adverse events that prompted its withdrawal from the market in 1997. Here, we review the experimental and clinical evidence of the efficacy of fenfluramine, including the latest results from ongoing clinical trials, and critically discuss the future potential of fenfluramine in terms of safety and precision medicine. Available data from the literature suggest a very good efficacy for both epileptic syndromes with a reduction in seizure burden and a longer seizure-free interval. We note the higher prevalence of evidence in patients with Dravet syndrome. Fenfluramine has been used in association with both first- and second-line medications, while its use in monotherapy still needs to be assessed.
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Affiliation(s)
- Ganna Balagura
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, and Maternal and Child Health, University of Genoa, Genoa, Italy.,Pediatric Neurology and Muscular Diseases Unit, IRCCS 'G. Gaslini' Institute, Genoa, Italy
| | - Marta Cacciatore
- Department of Pediatrics, University of L'Aquila, Via Vetoio 1, 67100, Coppito, L'Aquila, Italy.,Department of Pediatrics, University of Chieti, Chieti, Italy
| | - Eleonora A Grasso
- Department of Pediatrics, University of L'Aquila, Via Vetoio 1, 67100, Coppito, L'Aquila, Italy.,Department of Pediatrics, University of Chieti, Chieti, Italy
| | - Pasquale Striano
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, and Maternal and Child Health, University of Genoa, Genoa, Italy.,Pediatric Neurology and Muscular Diseases Unit, IRCCS 'G. Gaslini' Institute, Genoa, Italy
| | - Alberto Verrotti
- Department of Pediatrics, University of L'Aquila, Via Vetoio 1, 67100, Coppito, L'Aquila, Italy.
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31
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Lai WW, Galer BS, Wong PC, Farfel G, Pringsheim M, Keane MG, Agarwal A. Cardiovascular safety of fenfluramine in the treatment of Dravet syndrome: Analysis of an ongoing long-term open-label safety extension study. Epilepsia 2020; 61:2386-2395. [PMID: 32809271 PMCID: PMC7754414 DOI: 10.1111/epi.16638] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 07/16/2020] [Accepted: 07/16/2020] [Indexed: 01/03/2023]
Abstract
Objective Fenfluramine, which was previously approved as a weight loss drug, was withdrawn in 1997 when reports of cardiac valvulopathy emerged. The present study was conducted in part to characterize the cardiovascular safety profile of low‐dose fenfluramine when used in a pediatric population to reduce seizure frequency in patients with Dravet syndrome. Methods Patients 2‐ to 18‐years‐old with Dravet syndrome who had completed any of three randomized, placebo‐controlled clinical trials of fenfluramine were offered enrollment in this open‐label extension (OLE) study. All patients were treated with fenfluramine starting at a dose of 0.2 mg/kg/day (oral solution dosed twice per day), which was titrated to maximal effect with a dose limit of 0.7 mg/kg/day (maximum 26 mg/day) or 0.4 mg/kg/day (maximum 17 mg/day) in patients receiving concomitant stiripentol. Standardized echocardiographic examinations were conducted at Week 4 or 6 and then every 3 months during the OLE study to monitor cardiac valve function and structure and pulmonary artery pressure. The primary end point for the echocardiography analysis was the number of patients who developed valvular heart disease or pulmonary artery hypertension (PAH) during treatment. Results A total of 232 patients were enrolled in the study. The average age of patients was 9.1 ± 4.7 years, and 55.2% were male. The median duration of treatment with fenfluramine was 256 days (range = 58‐634 days), and the mean dose of fenfluramine was 0.41 mg/kg/day. No cases of valvular heart disease or PAH were observed. Significance Longitudinal echocardiography over a median 8.4 months of treatment with fenfluramine suggests a low risk of developing cardiac valvulopathy and PAH when used to treat pediatric patients with Dravet syndrome.
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Affiliation(s)
- Wyman W Lai
- Children's Hospital of Orange County, Orange, CA, USA
| | | | - Pierre C Wong
- Children's Hospital Los Angeles, Los Angeles, CA, USA
| | | | - Milka Pringsheim
- Department of Pediatric Cardiology, German Heart Centre Munich, Munich, Germany.,Pediatric Neurology, Schön Klinik Vogtareuth, Vogtareuth, Germany
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32
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Heyne HO, Baez-Nieto D, Iqbal S, Palmer DS, Brunklaus A, May P, Johannesen KM, Lauxmann S, Lemke JR, Møller RS, Pérez-Palma E, Scholl UI, Syrbe S, Lerche H, Lal D, Campbell AJ, Wang HR, Pan J, Daly MJ. Predicting functional effects of missense variants in voltage-gated sodium and calcium channels. Sci Transl Med 2020; 12:eaay6848. [PMID: 32801145 DOI: 10.1126/scitranslmed.aay6848] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 11/20/2019] [Accepted: 07/22/2020] [Indexed: 12/30/2022]
Abstract
Malfunctions of voltage-gated sodium and calcium channels (encoded by SCNxA and CACNA1x family genes, respectively) have been associated with severe neurologic, psychiatric, cardiac, and other diseases. Altered channel activity is frequently grouped into gain or loss of ion channel function (GOF or LOF, respectively) that often corresponds not only to clinical disease manifestations but also to differences in drug response. Experimental studies of channel function are therefore important, but laborious and usually focus only on a few variants at a time. On the basis of known gene-disease mechanisms of 19 different diseases, we inferred LOF (n = 518) and GOF (n = 309) likely pathogenic variants from the disease phenotypes of variant carriers. By training a machine learning model on sequence- and structure-based features, we predicted LOF or GOF effects [area under the receiver operating characteristics curve (ROC) = 0.85] of likely pathogenic missense variants. Our LOF versus GOF prediction corresponded to molecular LOF versus GOF effects for 87 functionally tested variants in SCN1/2/8A and CACNA1I (ROC = 0.73) and was validated in exome-wide data from 21,703 cases and 128,957 controls. We showed respective regional clustering of inferred LOF and GOF nucleotide variants across the alignment of the entire gene family, suggesting shared pathomechanisms in the SCNxA/CACNA1x family genes.
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Affiliation(s)
- Henrike O Heyne
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA.
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, 5WR36M Helsinki, Finland
| | - David Baez-Nieto
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Sumaiya Iqbal
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Center for Development of Therapeutics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Duncan S Palmer
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Andreas Brunklaus
- Paediatric Neurosciences Research Group, Royal Hospital for Sick Children, Glasgow G51 4TF, UK
- School of Medicine, University of Glasgow, Glasgow G12 8QQ, UK
| | - Patrick May
- Luxembourg Centre for Systems Biomedicine, Belvaux, University of Luxembourg, 4365 Esch-sur-Alzette, Luxembourg
| | - Katrine M Johannesen
- Department of Epilepsy Genetics and Personalized Treatment, Danish Epilepsy Centre, 4293 Dianalund, Denmark
- Department of Regional Health Research, University of Southern Denmark, 5230 Odense, Denmark
| | - Stephan Lauxmann
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, 72076 Tuebingen, Germany
| | - Johannes R Lemke
- Institute of Human Genetics, University of Leipzig Medical Center, 04103 Leipzig, Germany
| | - Rikke S Møller
- Department of Epilepsy Genetics and Personalized Treatment, Danish Epilepsy Centre, 4293 Dianalund, Denmark
- Department of Regional Health Research, University of Southern Denmark, 5230 Odense, Denmark
| | - Eduardo Pérez-Palma
- Cologne Center for Genomics (CCG), University of Cologne, 50923, Germany
- Genomic Medicine Institute, Lemer Research Institute Cleveland Clinic, OH G92J47, USA
| | - Ute I Scholl
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Nephrology and Medical Intensive Care and BIH Center for Regenerative Therapies, 10178 Berlin, Germany
- Berlin Institute of Health (BIH), 10178 Berlin, Germany
| | - Steffen Syrbe
- Division of Pediatric Epileptology, Center for Paediatrics and Adolescent Medicine, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, 72076 Tuebingen, Germany
| | - Dennis Lal
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Cologne Center for Genomics (CCG), University of Cologne, 50923, Germany
- Genomic Medicine Institute, Lemer Research Institute Cleveland Clinic, OH G92J47, USA
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH G92J47, USA
| | - Arthur J Campbell
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Center for Development of Therapeutics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Hao-Ran Wang
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Jen Pan
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Mark J Daly
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA.
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, 5WR36M Helsinki, Finland
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Gawel K, Langlois M, Martins T, van der Ent W, Tiraboschi E, Jacmin M, Crawford AD, Esguerra CV. Seizing the moment: Zebrafish epilepsy models. Neurosci Biobehav Rev 2020; 116:1-20. [PMID: 32544542 DOI: 10.1016/j.neubiorev.2020.06.010] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 04/20/2020] [Accepted: 06/05/2020] [Indexed: 12/14/2022]
Abstract
Zebrafish are now widely accepted as a valuable animal model for a number of different central nervous system (CNS) diseases. They are suitable both for elucidating the origin of these disorders and the sequence of events culminating in their onset, and for use as a high-throughput in vivo drug screening platform. The availability of powerful and effective techniques for genome manipulation allows the rapid modelling of different genetic epilepsies and of conditions with seizures as a core symptom. With this review, we seek to summarize the current knowledge about existing epilepsy/seizures models in zebrafish (both pharmacological and genetic) and compare them with equivalent rodent and human studies. New findings obtained from the zebrafish models are highlighted. We believe that this comprehensive review will highlight the value of zebrafish as a model for investigating different aspects of epilepsy and will help researchers to use these models to their full extent.
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Affiliation(s)
- Kinga Gawel
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway (NCMM), University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway; Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Jaczewskiego St. 8b, 20-090, Lublin, Poland
| | | | - Teresa Martins
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Belval, Luxembourg
| | - Wietske van der Ent
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway (NCMM), University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway
| | - Ettore Tiraboschi
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway (NCMM), University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway; Neurophysics Group, Center for Mind/Brain Sciences, University of Trento, Piazza Manifattura 1, Building 14, 38068, Rovereto, TN, Italy
| | - Maxime Jacmin
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Belval, Luxembourg
| | - Alexander D Crawford
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Belval, Luxembourg; Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), Oslo, Norway
| | - Camila V Esguerra
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway (NCMM), University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway.
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Wheless JW, Fulton SP, Mudigoudar BD. Dravet Syndrome: A Review of Current Management. Pediatr Neurol 2020; 107:28-40. [PMID: 32165031 DOI: 10.1016/j.pediatrneurol.2020.01.005] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 01/03/2020] [Accepted: 01/07/2020] [Indexed: 02/06/2023]
Abstract
Dravet syndrome is a debilitating epileptic encephalopathy of childhood with few treatment options available in the United States before 2018. In the modern era, new genetic testing options will allow diagnosis closer to disease onset. Three new medicines-stiripentol, cannabidiol, and fenfluramine-have documented efficacy and safety as adjunctive therapies for treating pharmacoresistant Dravet syndrome. Early diagnosis resulting in earlier treatment with these and other medications may improve prognosis of long-term outcomes, including less severity of cognitive, motor, and behavioral impairments. New rescue medication formulations can now manage acute seizures and help prevent status epilepticus via intranasal, buccal, and intramuscular routes as opposed to rectal administration. Preventing status epilepticus and generalized tonic-clonic seizures could potentially lower the risk of sudden unexpected death in epilepsy. With this changing landscape in diagnostic and treatment options comes questions and controversies for the practicing clinician, especially as diagnostic techniques outpace clinical treatment strategies. Critical decision points include when to start treatment, what pharmacotherapy combinations to try first, which rescue medication to recommend, and how to advise parents on controversial topics (e.g., immunizations). Given that most patients require polypharmacy, clinicians must be cognizant of drug-drug interactions between new medicines, existing anti-epileptic drugs, and other medications to manage comorbidities and must have an understanding of available therapeutic drug monitoring strategies and pharmacokinetic parameters. This review places new diagnostic, treatment and acute care options into the modern era and provides an overview of the challenges and opportunities facing the pediatric epileptologist in this rapidly changing landscape.
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Affiliation(s)
- James W Wheless
- Division of Pediatric Neurology, Department of Pediatrics & Neurology, University of Tennessee Health Science Center, Le Bonheur Children's Hospital, Memphis, Tennessee.
| | - Stephen P Fulton
- Division of Pediatric Neurology, Department of Pediatrics & Neurology, University of Tennessee Health Science Center, Le Bonheur Children's Hospital, Memphis, Tennessee
| | - Basanagoud D Mudigoudar
- Division of Pediatric Neurology, Department of Pediatrics & Neurology, University of Tennessee Health Science Center, Le Bonheur Children's Hospital, Memphis, Tennessee
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35
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Dozières-Puyravel B, Auvin S. Fenfluramine hydrochloride for the treatment of Dravet syndrome. Expert Opin Orphan Drugs 2020. [DOI: 10.1080/21678707.2020.1758930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
| | - Stéphane Auvin
- APHP, Service de Neurologie Pédiatrique, Hôpital Robert Debré, Paris, France
- INSERM NeuroDiderot, Université De Paris, Paris, France
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36
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Weuring WJ, Singh S, Volkers L, Rook MB, van ‘t Slot RH, Bosma M, Inserra M, Vetter I, Verhoeven-Duif NM, Braun KPJ, Rivara M, Koeleman BPC. NaV1.1 and NaV1.6 selective compounds reduce the behavior phenotype and epileptiform activity in a novel zebrafish model for Dravet Syndrome. PLoS One 2020; 15:e0219106. [PMID: 32134913 PMCID: PMC7058281 DOI: 10.1371/journal.pone.0219106] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 02/04/2020] [Indexed: 12/03/2022] Open
Abstract
Dravet syndrome is caused by dominant loss-of-function mutations in SCN1A which cause reduced activity of Nav1.1 leading to lack of neuronal inhibition. On the other hand, gain-of-function mutations in SCN8A can lead to a severe epileptic encephalopathy subtype by over activating NaV1.6 channels. These observations suggest that Nav1.1 and Nav1.6 represent two opposing sides of the neuronal balance between inhibition and activation. Here, we hypothesize that Dravet syndrome may be treated by either enhancing Nav1.1 or reducing Nav1.6 activity. To test this hypothesis we generated and characterized a novel DS zebrafish model and tested new compounds that selectively activate or inhibit the human NaV1.1 or NaV1.6 channel respectively. We used CRISPR/Cas9 to generate two separate Scn1Lab knockout lines as an alternative to previous zebrafish models generated by random mutagenesis or morpholino oligomers. Using an optimized locomotor assay, spontaneous burst movements were detected that were unique to Scn1Lab knockouts and disappear when introducing human SCN1A mRNA. Besides the behavioral phenotype, Scn1Lab knockouts show sudden, electrical discharges in the brain that indicate epileptic seizures in zebrafish. Scn1Lab knockouts showed increased sensitivity to the GABA antagonist pentylenetetrazole and a reduction in whole organism GABA levels. Drug screenings further validated a Dravet syndrome phenotype. We tested the NaV1.1 activator AA43279 and two novel NaV1.6 inhibitors MV1369 and MV1312 in the Scn1Lab knockouts. Both type of compounds significantly reduced the number of spontaneous burst movements and seizure activity. Our results show that selective inhibition of NaV1.6 could be just as efficient as selective activation of NaV1.1 and these approaches could prove to be novel potential treatment strategies for Dravet syndrome and other (genetic) epilepsies. Compounds tested in zebrafish however, should always be further validated in other model systems for efficacy in mammals and to screen for potential side effects.
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Affiliation(s)
- Wout J. Weuring
- Department of Genetics, Center for Molecular Medicine, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Sakshi Singh
- Department of Genetics, Center for Molecular Medicine, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Linda Volkers
- Department of Cardiology, Laboratory of Experimental Cardiology, University Medical Centre Leiden, Leiden, the Netherlands
| | - Martin B. Rook
- Department of Medical Physiology, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Ruben H. van ‘t Slot
- Department of Genetics, Center for Molecular Medicine, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Marjolein Bosma
- Department of Genetics, Center for Molecular Medicine, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Marco Inserra
- Centre for Pain Research & School of Pharmacy, University of Queensland, Brisbane, Australia
| | - Irina Vetter
- Centre for Pain Research & School of Pharmacy, University of Queensland, Brisbane, Australia
| | - Nanda M. Verhoeven-Duif
- Department of Genetics, Center for Molecular Medicine, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Kees P. J. Braun
- Department of Neurology, University Medical Centre Utrecht, Utrecht, the Netherlands
| | - Mirko Rivara
- Food and Drug Department, University of Parma, Parma, Italy
| | - Bobby P. C. Koeleman
- Department of Genetics, Center for Molecular Medicine, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
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Ren A, Zhu X, Feichtinger K, Lehman J, Kasem M, Schrader TO, Wong A, Dang H, Le M, Frazer J, Unett DJ, Grottick AJ, Whelan KT, Morgan ME, Sage CR, Semple G. Discovery of a lead series of potent benzodiazepine 5-HT2C receptor agonists with high selectivity in functional and binding assays. Bioorg Med Chem Lett 2020; 30:126929. [DOI: 10.1016/j.bmcl.2019.126929] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 12/17/2019] [Accepted: 12/20/2019] [Indexed: 02/06/2023]
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Higgins GA, Fletcher PJ, Shanahan WR. Lorcaserin: A review of its preclinical and clinical pharmacology and therapeutic potential. Pharmacol Ther 2020; 205:107417. [DOI: 10.1016/j.pharmthera.2019.107417] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Accepted: 09/30/2019] [Indexed: 12/17/2022]
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39
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Lagae L, Sullivan J, Knupp K, Laux L, Polster T, Nikanorova M, Devinsky O, Cross JH, Guerrini R, Talwar D, Miller I, Farfel G, Galer BS, Gammaitoni A, Mistry A, Morrison G, Lock M, Agarwal A, Lai WW, Ceulemans B. Fenfluramine hydrochloride for the treatment of seizures in Dravet syndrome: a randomised, double-blind, placebo-controlled trial. Lancet 2019; 394:2243-2254. [PMID: 31862249 DOI: 10.1016/s0140-6736(19)32500-0] [Citation(s) in RCA: 202] [Impact Index Per Article: 40.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 03/21/2019] [Accepted: 08/30/2019] [Indexed: 12/29/2022]
Abstract
BACKGROUND Dravet syndrome is a rare, treatment-resistant developmental epileptic encephalopathy characterised by multiple types of frequent, disabling seizures. Fenfluramine has been reported to have antiseizure activity in observational studies of photosensitive epilepsy and Dravet syndrome. The aim of the present study was to assess the efficacy and safety of fenfluramine in patients with Dravet syndrome. METHODS In this randomised, double-blind, placebo-controlled clinical trial, we enrolled children and young adults with Dravet syndrome. After a 6-week observation period to establish baseline monthly convulsive seizure frequency (MCSF; convulsive seizures were defined as hemiclonic, tonic, clonic, tonic-atonic, generalised tonic-clonic, and focal with clearly observable motor signs), patients were randomly assigned through an interactive web response system in a 1:1:1 ratio to placebo, fenfluramine 0·2 mg/kg per day, or fenfluramine 0·7 mg/kg per day, added to existing antiepileptic agents for 14 weeks. The primary outcome was the change in mean monthly frequency of convulsive seizures during the treatment period compared with baseline in the 0·7 mg/kg per day group versus placebo; 0·2 mg/kg per day versus placebo was assessed as a key secondary outcome. Analysis was by modified intention to treat. Safety analyses included all participants who received at least one dose of study medication. This trial is registered with ClinicalTrials.gov with two identical protocols NCT02682927 and NCT02826863. FINDINGS Between Jan 15, 2016, and Aug 14, 2017, we assessed 173 patients, of whom 119 patients (mean age 9·0 years, 64 [54%] male) were randomly assigned to receive either fenfluramine 0·2 mg/kg per day (39), fenfluramine 0·7 mg/kg per day (40) or placebo (40). During treatment, the median reduction in seizure frequency was 74·9% in the fenfluramine 0·7 mg/kg group (from median 20·7 seizures per 28 days to 4·7 seizures per 28 days), 42·3% in the fenfluramine 0·2 mg/kg group (from median 17·5 seizures per 28 days to 12·6 per 28 days), and 19·2% in the placebo group (from median 27·3 per 28 days to 22·0 per 28 days). The study met its primary efficacy endpoint, with fenfluramine 0·7 mg/kg per day showing a 62·3% greater reduction in mean MCSF compared with placebo (95% CI 47·7-72·8, p<0·0001); fenfluramine 0·2 mg/kg per day showed a 32·4% reduction in mean MCSF compared with placebo (95% CI 6·2-52·3, p=0·0209). The most common adverse events (occurring in at least 10% of patients and more frequently in the fenfluramine groups) were decreased appetite, diarrhoea, fatigue, lethargy, somnolence, and decreased weight. Echocardiographic examinations revealed valve function within the normal physiological range in all patients during the trial and no signs of pulmonary arterial hypertension. INTERPRETATION In Dravet syndrome, fenfluramine provided significantly greater reduction in convulsive seizure frequency compared with placebo and was generally well tolerated, with no observed valvular heart disease or pulmonary arterial hypertension. Fenfluramine could be an important new treatment option for patients with Dravet syndrome. FUNDING Zogenix.
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Affiliation(s)
- Lieven Lagae
- Department of Paediatric Neurology, University of Leuven, Leuven, Belgium
| | - Joseph Sullivan
- University of California, San Francisco Benioff Children's Hospital, San Francisco, CA, USA
| | - Kelly Knupp
- University of Colorado, Children's Hospital Colorado, Aurora, CO, USA
| | - Linda Laux
- Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | | | | | | | - J Helen Cross
- UCL Great Ormond Street NIHR BRC Institute of Child Health, London, UK
| | | | - Dinesh Talwar
- University of Arizona Health Sciences Center, Tucson, AZ, USA
| | - Ian Miller
- Nicklaus Children's Hospital, Miami, FL, USA
| | | | | | | | | | | | | | | | | | - Berten Ceulemans
- Department of Paediatric Neurology, University of Antwerp, Edegem, Belgium
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40
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Berkovic SF. Epileptic encephalopathies of infancy: welcome advances. Lancet 2019; 394:2203-2204. [PMID: 31862247 DOI: 10.1016/s0140-6736(19)31239-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 05/09/2019] [Indexed: 11/23/2022]
Affiliation(s)
- Samuel F Berkovic
- Epilepsy Research Centre, University of Melbourne, Melbourne, VIC 3084, Australia.
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41
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Silenieks LB, Carroll NK, Van Niekerk A, Van Niekerk E, Taylor C, Upton N, Higgins GA. Evaluation of Selective 5-HT 2C Agonists in Acute Seizure Models. ACS Chem Neurosci 2019; 10:3284-3295. [PMID: 31082204 DOI: 10.1021/acschemneuro.8b00739] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The 5-HT releaser/reuptake inhibitor fenfluramine has been recently reported to provide benefit as an adjunctive treatment for Dravet and Lennox-Gastaut syndromes, two types of severe childhood epilepsy. Despite its enhancement of 5-HT function, many effects of fenfluramine have been demonstrated to be dependent on 5-HT2C receptor activation, suggesting that 5-HT2C receptor activation may have an anticonvulsant property. The present study was designed to evaluate fenfluramine and 5-HT agonists of varying 5-HT2C agonist selectivity, the relatively nonselective mCPP and Ro 60-0175, and the selective 5-HT2C agonists lorcaserin and CP-809101 across a variety of acute seizure tests conducted in adult rats and mice, which have been instrumental in identifying the majority of clinically efficacious antiepileptic drugs. Tests included the maximal electroshock seizure (MES), MES threshold, and 6 Hz electrical convulsive seizure models and the chemoconvulsant pentylenetetrazole test. The effect of mCPP, lorcaserin, and CP-809101 against electrically evoked seizures in amygdala kindled rats was also investigated. Overall, at doses known to interact with 5-HT2CR, there was no clear class-related effect of these agonists in any test. The only notable antiseizure effect of fenfluramine was inhibition of MES-induced tonic seizures in the rat. The current preclinical studies using the classical acute seizure tests and an amygdala kindling model do not identify a reliable antiseizure effect of fenfluramine, an agent now used in the treatment of human epilepsies, including Dravet syndrome and Lennox-Gastaut syndrome. Given the nature of these epilepsies, early life and/or genetic models may have better construct validity and be more appropriate for further study.
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Affiliation(s)
- Leonardo B. Silenieks
- Intervivo Solutions Inc, Toronto, ON M5A 4K2, Canada
- Vivocore, Toronto, ON N1M 2W4, Canada
| | | | | | | | | | - Neil Upton
- Transpharmation Ltd, London NW10NH, United Kingdom
| | - Guy A. Higgins
- Intervivo Solutions Inc, Toronto, ON M5A 4K2, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON ON M5S, Canada
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42
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An Old Drug for a New Indication: Repurposing Fenfluramine From an Anorexigen to an Antiepileptic Drug. Clin Pharmacol Ther 2019; 106:929-932. [DOI: 10.1002/cpt.1469] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 03/29/2019] [Indexed: 11/07/2022]
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43
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Tupal S, Faingold CL. Fenfluramine, a serotonin-releasing drug, prevents seizure-induced respiratory arrest and is anticonvulsant in the DBA/1 mouse model of SUDEP. Epilepsia 2019; 60:485-494. [PMID: 30719703 DOI: 10.1111/epi.14658] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 01/02/2019] [Accepted: 01/07/2019] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Prevention of sudden unexpected death in epilepsy (SUDEP) is a critical goal for epilepsy therapy. The DBA/1 mouse model of SUDEP exhibits an elevated susceptibility to seizure-induced death in response to electroconvulsive shock, hyperthermia, convulsant drug, and acoustic stimulation. The serotonin hypothesis of SUDEP is based on findings that treatments which modify serotonergic function significantly alter susceptibility to seizure-induced sudden death in several epilepsy models, including DBA/1 mice. Serotonergic abnormalities have also recently been observed in human SUDEP. Fenfluramine is a drug that enhances serotonin release in the brain. Recent studies have found that the addition of fenfluramine improved seizure control in patients with Dravet syndrome, which has a high incidence of SUDEP. Therefore, we investigated the effects of fenfluramine on seizures and seizure-induced respiratory arrest (S-IRA) in DBA/1 mice. METHODS The dose and time course of the effects of fenfluramine (i.p.) on audiogenic seizures (Sz) induced by an electric bell in DBA/1 mice were determined. Videos of Sz-induced behaviors were recorded for analysis. Statistical significance (P < 0.05) was evaluated using the chi-square test. RESULTS Sixteen hours after administration of 15 mg/kg of fenfluramine, a high incidence of selective block of S-IRA susceptibility (P < 0.001) occurred in DBA/1 mice without blocking any convulsive behavior. Thirty minutes after 20-40 mg/kg of fenfluramine, significant reductions of seizure incidence and severity, as well as S-IRA susceptibility occurred, which were long-lasting (≥48 hours). The median effective dose (ED50 ) of fenfluramine for significantly reducing Sz at 30 minutes was 21 mg/kg. SIGNIFICANCE This study presents the first evidence for the effectiveness of fenfluramine in reducing seizure incidence, severity, and S-IRA susceptibility in a mammalian SUDEP model. The ability of fenfluramine to block S-IRA selectively suggests the potential usefulness of fenfluramine in prophylaxis of SUDEP. These results further confirm and extend the serotonin hypothesis of SUDEP.
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Affiliation(s)
- Srinivasan Tupal
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, Illinois
| | - Carl L Faingold
- Departments of Pharmacology and Neurology, Southern Illinois University School of Medicine, Springfield, Illinois
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44
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Polster T. Individualized treatment approaches: Fenfluramine, a novel antiepileptic medication for the treatment of seizures in Dravet syndrome. Epilepsy Behav 2019; 91:99-102. [PMID: 30269941 DOI: 10.1016/j.yebeh.2018.08.021] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Revised: 08/16/2018] [Accepted: 08/16/2018] [Indexed: 01/02/2023]
Abstract
Dravet syndrome is a rare and severe encephalopathy that first presents in infancy with seizures refractory to conventional antiepileptic drugs. Forty-five percent of patients report four or more tonic-clonic seizures per month despite multidrug regimens. Fenfluramine, an amphetamine derivative, was initially developed as an appetite suppressant with a serotonergic mechanism of action. Clinical observation of a potential antiepileptic activity in a small homogeneous cohort of patients combined with a genetic workup of these patients led to the hypothesis of fenfluramine as a treatment for seizures in Dravet syndrome. This concept was successfully evaluated in a zebrafish model and led to a Phase 3 trial of fenfluramine to treat seizures in children with Dravet syndrome. Preliminary results of the trial suggest that fenfluramine may be a highly effective, well-tolerated treatment for patients with Dravet syndrome. This short review summarizes the history of use of fenfluramine from the initial clinical observations followed by preclinical studies and subsequent successful clinical trial. This article is part of the Special Issue "Individualized Epilepsy Management: Medicines, Surgery and Beyond."
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Affiliation(s)
- Tilman Polster
- Paediatric Epileptology, Mara Hospital, Bethel Epilepsy Centre, Bielefeld, Germany.
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45
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Brigo F, Striano P, Balagura G, Belcastro V. Emerging drugs for the treatment of Dravet syndrome. Expert Opin Emerg Drugs 2018; 23:261-269. [DOI: 10.1080/14728214.2018.1552937] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Francesco Brigo
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
- Division of Neurology, “Franz Tappeiner” Hospital, Merano, Italy
| | - Pasquale Striano
- Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, “G. Gaslini” Institute, Genova, Italy
| | - Ganna Balagura
- Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, “G. Gaslini” Institute, Genova, Italy
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Abstract
PURPOSE OF REVIEW Dravet syndrome is a rare but severe genetic epilepsy that has unique treatment challenges. This is a review of current and future potential treatment options. RECENT FINDINGS Treatment for Dravet syndrome should encompass many aspects of the syndrome such as gait, behavior, and nutrition, as well as focus on seizure control. Many sodium channel blockers should be avoided as they are likely to exacerbate seizures. Current options for treatment include valproic acid, clobazam, stiripentol, and ketogenic diet. Testing is underway for several new treatment options with unique mechanisms of action and therapeutic targets, including the serotonin system and genetic modulation. Accurate and early diagnosis of Dravet syndrome will lead to avoidance of medications that may exacerbate seizures. Additionally, a multi-disciplinary approach and careful planning for management of episodes of status epilepticus may lead to improved outcomes. Ongoing research for novel approaches to treatment creates optimism for future improvement in outcomes.
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Lagae L, Schoonjans AS, Gammaitoni AR, Galer BS, Ceulemans B. A pilot, open-label study of the effectiveness and tolerability of low-dose ZX008 (fenfluramine HCl) in Lennox-Gastaut syndrome. Epilepsia 2018; 59:1881-1888. [DOI: 10.1111/epi.14540] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 07/23/2018] [Accepted: 07/23/2018] [Indexed: 11/30/2022]
Affiliation(s)
- Lieven Lagae
- Department of Development and Regeneration; Division of Pediatric Neurology; University of Leuven; Leuven Belgium
| | - An-Sofie Schoonjans
- Division of Pediatric Neurology; Antwerp University Hospital; University of Antwerp; Edegem Belgium
| | | | | | - Berten Ceulemans
- Division of Pediatric Neurology; Antwerp University Hospital; University of Antwerp; Edegem Belgium
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48
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Rodríguez-Muñoz M, Sánchez-Blázquez P, Garzón J. Fenfluramine diminishes NMDA receptor-mediated seizures via its mixed activity at serotonin 5HT2A and type 1 sigma receptors. Oncotarget 2018; 9:23373-23389. [PMID: 29805740 PMCID: PMC5955088 DOI: 10.18632/oncotarget.25169] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 04/03/2018] [Indexed: 10/27/2022] Open
Abstract
Fenfluramine exhibits antiepileptic properties and thus diminishes epileptiform discharges in experimental animal models of Dravet syndrome. Fenfluramine is metabolized into norfenfluramine in vivo, which shows greater affinity and agonist activity at serotonin 5HT2 receptors (5HT2R) than fenfluramine. In this study, we found that fenfluramine and norfenfluramine disrupted the regulatory association of the sigma 1 receptor (σ1R) with NR1 subunits of glutamate N-methyl-D-aspartate receptors (NMDAR), an effect that was also produced by σ1R antagonists such as S1RA and prevented by σ1R agonists such as PPCC. The antagonists removed σ1R bound to NMDAR NR1 subunits enabling calcium-regulated calmodulin (CaM) to bind to those subunits. As a result, CaM may inhibit calcium permeation through NMDARs. The serotoninergic activity of fenfluramine at 5HT2AR, and likely also at 5HT2CR, collaborated with its activity at σ1Rs to prevent the convulsive syndrome promoted by NMDAR overactivation. Notably, fenfluramine enhanced the inhibitory coupling of G protein-coupled receptors such as 5HT1AR and cannabinoid type 1 receptor with NMDARs, thus allowing the more effective restrain of NMDAR activity. Thus, fenfluramine circumvents the negative side effects of direct NMDAR antagonists and may improve the quality of life of subjects affected by such proconvulsant dysfunctions.
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Affiliation(s)
- María Rodríguez-Muñoz
- Neuropharmacology, Department of Translational Neurosciences, Cajal Institute, CSIC, Madrid E-28002, Spain
| | - Pilar Sánchez-Blázquez
- Neuropharmacology, Department of Translational Neurosciences, Cajal Institute, CSIC, Madrid E-28002, Spain
| | - Javier Garzón
- Neuropharmacology, Department of Translational Neurosciences, Cajal Institute, CSIC, Madrid E-28002, Spain
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49
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Eimon PM, Ghannad-Rezaie M, De Rienzo G, Allalou A, Wu Y, Gao M, Roy A, Skolnick J, Yanik MF. Brain activity patterns in high-throughput electrophysiology screen predict both drug efficacies and side effects. Nat Commun 2018; 9:219. [PMID: 29335539 PMCID: PMC5768723 DOI: 10.1038/s41467-017-02404-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 11/25/2017] [Indexed: 11/26/2022] Open
Abstract
Neurological drugs are often associated with serious side effects, yet drug screens typically focus only on efficacy. We demonstrate a novel paradigm utilizing high-throughput in vivo electrophysiology and brain activity patterns (BAPs). A platform with high sensitivity records local field potentials (LFPs) simultaneously from many zebrafish larvae over extended periods. We show that BAPs from larvae experiencing epileptic seizures or drug-induced side effects have substantially reduced complexity (entropy), similar to reduced LFP complexity observed in Parkinson’s disease. To determine whether drugs that enhance BAP complexity produces positive outcomes, we used light pulses to trigger seizures in a model of Dravet syndrome, an intractable genetic epilepsy. The highest-ranked compounds identified by BAP analysis exhibit far greater anti-seizure efficacy and fewer side effects during subsequent in-depth behavioral assessment. This high correlation with behavioral outcomes illustrates the power of brain activity pattern-based screens and identifies novel therapeutic candidates with minimal side effects. One challenge in drug screening for neurological disorders is how to accurately capture disease pathology and side effects. Here, the authors developed a multi-channel recording platform based on a zebrafish genetic model of epilepsy to screen for antiepileptic drugs.
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Affiliation(s)
- Peter M Eimon
- Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
| | - Mostafa Ghannad-Rezaie
- Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.,UZH/ETH Irchel Campus, Y17-L76, Winterthurerstrasse 190, 8057, Zürich, Switzerland
| | - Gianluca De Rienzo
- Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.,Intellimedix, Cambridge, MA, 02139, USA.,Axcella Health, 840 Memorial Dr, Cambridge, MA, 02139, USA
| | - Amin Allalou
- Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - Yuelong Wu
- Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - Mu Gao
- Georgia Institute of Technology, 950 Atlantic Drive, Room 2151, Atlanta, GA, 30332, USA
| | - Ambrish Roy
- Georgia Institute of Technology, 950 Atlantic Drive, Room 2151, Atlanta, GA, 30332, USA
| | - Jeffrey Skolnick
- Georgia Institute of Technology, 950 Atlantic Drive, Room 2151, Atlanta, GA, 30332, USA
| | - Mehmet Fatih Yanik
- Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA. .,UZH/ETH Irchel Campus, Y17-L76, Winterthurerstrasse 190, 8057, Zürich, Switzerland.
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50
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Schoonjans AS, Marchau F, Paelinck BP, Lagae L, Gammaitoni A, Pringsheim M, Keane MG, Ceulemans B. Cardiovascular safety of low-dose fenfluramine in Dravet syndrome: a review of its benefit-risk profile in a new patient population. Curr Med Res Opin 2017; 33:1773-1781. [PMID: 28704161 DOI: 10.1080/03007995.2017.1355781] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
OBJECTIVE Dravet syndrome (DS) is a rare, treatment-resistant epilepsy syndrome for which current treatment regimens are often ineffective. Fenfluramine is currently in development for treatment of DS, based on reports in the 1980s and 1990s of its anti-epileptic activity in pediatric patients with intractable epilepsy. However, fenfluramine was withdrawn from global markets in 1997 following reports of its association with pulmonary hypertension and heart valve disease in adult patients treated for obesity. This review was conducted to assess cardiac safety of fenfluramine when used at lower doses for treatment of DS. METHODS Pubmed was searched for clinical studies of fenfluramine in obese adults who reported incidence of heart valve disease. These data were reviewed against published results from Belgian patients with DS who have been treated with low-dose fenfluramine for up to 28 years. RESULTS Nine controlled studies of fenfluramine and related compounds (dexfenfluramine and/or phentermine) which assessed incidence and severity of cardiac valve disease in 3,268 treated patients and 2,017 control subjects have been reported. Mild or greater aortic valve regurgitation was found in 9.6% of treated patients compared with 3.9% of control subjects, and moderate or greater mitral valve regurgitation was found in 3.1% of treated patients and 2.5% of control subjects. Nineteen DS patients have been treated for up to 28 years with 10-20 mg/day fenfluramine, with no clinical signs or symptoms of cardiac valve disease or pulmonary hypertension. Slight and clinically unimportant changes in valve structure have been seen on echocardiography in five patients at some time during the observation period. CONCLUSIONS A different benefit-risk relationship appears to be emerging when fenfluramine is used at low doses for extended periods in young patients with DS. Continued cardiac assessments during ongoing Phase 3 clinical trials will provide additional safety information for this potential new and effective treatment.
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Affiliation(s)
- An-Sofie Schoonjans
- a Department of Paediatric Neurology , Antwerp University Hospital, University of Antwerp , Antwerp , Belgium
| | - Fabienne Marchau
- b Department of Paediatric Cardiology , Antwerp University Hospital, University of Antwerp , Antwerp , Belgium
| | - Bernard P Paelinck
- c Department of Cardiology , Antwerp University Hospital, University of Antwerp , Antwerp , Belgium
| | - Lieven Lagae
- d Department of Development and Regeneration , Section of Paediatric Neurology, University Hospitals Gasthuisberg , Leuven , Belgium
| | | | - Milka Pringsheim
- f Department of Pediatric Cardiology , German Heart Centre Munich , Munich , Germany
- g Pediatric Neurology, Schön Klinik Vogtareuth , Vogtareuth , Germany
| | | | - Berten Ceulemans
- a Department of Paediatric Neurology , Antwerp University Hospital, University of Antwerp , Antwerp , Belgium
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