1
|
Chen Y, Li W, Lu C, Gao X, Song H, Zhang Y, Zhao S, Cai G, Guo Q, Zhou D, Chen Y. Efficacy, tolerability and safety of add-on third-generation antiseizure medications in treating focal seizures worldwide: a network meta-analysis of randomised, placebo-controlled trials. EClinicalMedicine 2024; 70:102513. [PMID: 38449838 PMCID: PMC10915785 DOI: 10.1016/j.eclinm.2024.102513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Revised: 02/13/2024] [Accepted: 02/16/2024] [Indexed: 03/08/2024] Open
Abstract
Background Adjunctive newer antiseizure medications (ASMs) are being used in patients with treatment-resistant focal-onset seizures (FOS). An updated network meta-analysis (NMA) was necessary to compile evidence in this critical area. Methods We systematically searched PubMed, Embase, Cochrane Library, Web of Science, and Scopus from their inception until 17 January 2024, evaluating the efficacy, tolerability, and safety of rufinamide (RUF), brivaracetam (BRV), cenobamate (CNB), eslicarbazepine (ESL), lacosamide (LCM), retigabine (RTG), and perampanel (PER) as adjunctive treatments for FOS. Efficacy outcomes included seizure response and seizure freedom. Tolerability was assessed by discontinuation due to adverse events (AEs). Safety outcomes were evaluated based on the number of patients experiencing at least one AE and serious adverse events (SAEs). This review is registered with PROSPERO (CRD42023485130). Findings A total of 29 studies involving 11,750 participants were included. For seizure response, all ASMs were significantly superior to placebo, with RTG ranking highest, followed by CNB. Considering dosage, CNB 400 mg/d was top-ranked, followed by RTG 1200 mg/d. For seizure freedom, BRV was highest-ranked, followed by CNB, with BRV 100 mg/d leading, followed by CNB 400 mg/d. Regarding tolerability, LCM 600 mg/d had the lowest ranking, followed by CNB 400 mg/d. For the safety outcome of AEs, ESL 1200 mg/d was ranked lowest, followed by CNB 400 mg/d. Regarding SAEs, LCM 400 mg/d was ranked lowest, followed by RTG 1200 mg/d. Interpretation ASMs at different dosages have varying efficacy and tolerability profiles. We have provided hierarchical rankings of ASMs for efficacy and safety outcomes. Our findings offer the most comprehensive evidence available to inform patients, families, physicians, guideline developers, and policymakers about the choice of ASMs in patients with treatment-resistant FOS. Funding None.
Collapse
Affiliation(s)
- Yankun Chen
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China
| | - Wenze Li
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China
| | - Chenfei Lu
- Department of Respiratory, The Ninth People's Hospital of Chongqing, Chongqing, 400700, China
| | - Xinxia Gao
- Department of Medical Records, Heze Municipal Hospital, Heze, 274000, China
| | - Huizhen Song
- Department of Neurology, Heze Third People's Hospital, Heze, 274000, China
| | - Yanli Zhang
- Department of Neurology, Shandong Provincial Hospital Heze Branch, Heze, 274000, China
| | - Sihao Zhao
- Department of Neurology, Heze Mudan District People's Hospital, Heze, 274000, China
| | - Gaoang Cai
- Department of Neurology, Juancheng County People's Hospital, Juancheng, 274600, China
| | - Qing Guo
- Department of Neurology, Heze Municipal Hospital Brain Hospital, Heze, 274000, China
| | - Dongdong Zhou
- Mental Health Center, University-Town Hospital of Chongqing Medical University, Chongqing, 401331, China
| | - Yangmei Chen
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China
| |
Collapse
|
2
|
Beirow K, Schmidt C, Jürgen B, Schlüter R, Schweder T, Bednarski PJ. Investigation of TGF-α-overexpressing mouse hepatocytes (TAMH) cultured as spheroids for use in hepatotoxicity screening of drug candidates. J Appl Toxicol 2024; 44:272-286. [PMID: 37655636 DOI: 10.1002/jat.4538] [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: 04/25/2023] [Revised: 07/24/2023] [Accepted: 08/15/2023] [Indexed: 09/02/2023]
Abstract
The immortalized mouse liver cell line TAMH has been described as a valuable tool for studying hepatotoxic mechanisms, but until now, it has only been reported to grow as a monolayer in culture. However, culturing hepatocytes as three-dimensional (3D) spheroids has been shown to result in improved liver-specific functions (e.g., metabolic capacity) by better mimicking the in vivo environment. This approach may lead to more reliable detection of drug-induced liver injury (DILI) in the early phase of drug discovery, preventing post-marketing drug withdrawals. Here, we investigated the cultivation of TAMH as 3D spheroids, characterizing them with optical and transmission electron microscopy as well as analyzing their gene expression at mRNA level (especially drug-metabolizing enzymes) compared to TAMH monolayer. In addition, comparisons were made with spheroids grown from the human hepatoblastoma cell line HepG2, another current spheroid model. The results indicate that TAMH spheroids express hepatic structures and show elevated levels of some of the key phase I and II drug-metabolizing enzymes, in contrast to TAMH monolayer. The in vitro hepatotoxic potencies of the drugs acetaminophen and flupirtine maleate were found to be very similar between TAMH spheroidal and the monolayer cultures. Both the advantages and disadvantages of TAMH spheroids as an in vitro hepatotoxicity model compared to monolayer model are discussed.
Collapse
Affiliation(s)
- Kristin Beirow
- Department of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, University of Greifswald, Greifswald, Germany
| | - Christian Schmidt
- Department of Pharmaceutical Biotechnology Institute of Pharmacy, University of Greifswald, Greifswald, Germany
| | - Britta Jürgen
- Department of Pharmaceutical Biotechnology Institute of Pharmacy, University of Greifswald, Greifswald, Germany
| | - Rabea Schlüter
- Imaging Center of the Department of Biology, University of Greifswald, Greifswald, Germany
| | - Thomas Schweder
- Department of Pharmaceutical Biotechnology Institute of Pharmacy, University of Greifswald, Greifswald, Germany
| | - Patrick J Bednarski
- Department of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, University of Greifswald, Greifswald, Germany
| |
Collapse
|
3
|
Quiñonez M, DiFranco M, Wu F, Cannon SC. Retigabine suppresses loss of force in mouse models of hypokalaemic periodic paralysis. Brain 2023; 146:1554-1560. [PMID: 36718088 PMCID: PMC10115351 DOI: 10.1093/brain/awac441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Revised: 10/18/2022] [Accepted: 11/12/2022] [Indexed: 02/01/2023] Open
Abstract
Recurrent episodes of weakness in periodic paralysis are caused by intermittent loss of muscle fibre excitability, as a consequence of sustained depolarization of the resting potential. Repolarization is favoured by increasing the fibre permeability to potassium. Based on this principle, we tested the efficacy of retigabine, a potassium channel opener, to suppress the loss of force induced by a low-K+ challenge in hypokalaemic periodic paralysis (HypoPP). Retigabine can prevent the episodic loss of force in HypoPP. Knock-in mutant mouse models of HypoPP (Cacna1s p.R528H and Scn4a p.R669H) were used to determine whether pre-treatment with retigabine prevented the loss of force, or post-treatment hastened recovery of force for a low-K+ challenge in an ex vivo contraction assay. Retigabine completely prevents the loss of force induced by a 2 mM K+ challenge (protection) in our mouse models of HypoPP, with 50% inhibitory concentrations of 0.8 ± 0.13 μM and 2.2 ± 0.42 μM for NaV1.4-R669H and CaV1.1-R528H, respectively. In comparison, the effective concentration for the KATP channel opener pinacidil was 10-fold higher. Application of retigabine also reversed the loss of force (rescue) for HypoPP muscle maintained in 2 mM K+. Our findings show that retigabine, a selective agonist of the KV7 family of potassium channels, is effective for the prevention of low-K+ induced attacks of weakness and to enhance recovery from an ongoing loss of force in mouse models of type 1 (Cacna1s) and type 2 (Scn4a) HypoPP. Substantial protection from the loss of force occurred in the low micromolar range, well within the therapeutic window for retigabine.
Collapse
Affiliation(s)
- Marbella Quiñonez
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Marino DiFranco
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Fenfen Wu
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Stephen C Cannon
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.,Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| |
Collapse
|
4
|
Namdari R, Luzon C, Cadieux JA, Leung J, Beatch GN. Pharmacokinetics of XEN496, a Novel Pediatric Formulation of Ezogabine, Under Fed and Fasted Conditions: A Phase 1 Trial. Neurol Ther 2022; 11:781-796. [PMID: 35380370 PMCID: PMC9095778 DOI: 10.1007/s40120-022-00343-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Accepted: 03/09/2022] [Indexed: 10/27/2022] Open
Abstract
INTRODUCTION XEN496 is a novel, granular, immediate-release formulation of ezogabine intended for pediatric use. The objective of this study was to assess the effect of food on the pharmacokinetics (PK) of XEN496 and its N-acetyl metabolite (NAMR) in healthy volunteers. METHODS Twenty-four adult subjects were enrolled in this phase 1, single center, open-label, randomized, single-dose, two-way crossover study. Subjects received 400 mg XEN496 as an oral suspension in both fed and fasted states separated by a 6-day washout period. Serial blood samples were collected up to 48 h post-administration. PK parameters evaluated included maximum observed plasma concentration (Cmax), time of maximum observed plasma concentration (Tmax), and area under the concentration-time curve (AUC(0-t) and AUCinf). Safety was assessed by laboratory evaluations, physical exam, and adverse event monitoring. RESULTS For XEN496, median Tmax was 3 and 2 h in the fed and fasted states, respectively. AUC parameters in the fed and fasted states were equivalent, whereas food decreased Cmax of XEN496 by 32% compared to the fasted state. The ratio of geometric means [90% CI] for Cmax was 72% [64-82%]. For NAMR, food delayed Tmax by 1 h, while Cmax and AUC parameters were equivalent in the fed and fasted states. The safety profile of XEN496 in this study appeared comparable to that previously reported for ezogabine tablets. CONCLUSION The biopharmaceutical performance of XEN496 in this study was as expected for an immediate-release, granular dosage formulation, and generally comparable to that reported for ezogabine tablets. Future studies are needed to characterize the efficacy, safety, and PK of XEN496 in a pediatric population.
Collapse
Affiliation(s)
- Rostam Namdari
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, BC, V5G 4W8, Canada.
| | - Constanza Luzon
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, BC, V5G 4W8, Canada
| | - Jay A Cadieux
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, BC, V5G 4W8, Canada
| | - Jennifer Leung
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, BC, V5G 4W8, Canada
| | - Gregory N Beatch
- Xenon Pharmaceuticals Inc., 200-3650 Gilmore Way, Burnaby, BC, V5G 4W8, Canada
| |
Collapse
|
5
|
Bloms-Funke P, Bankstahl M, Bankstahl J, Kneip C, Schröder W, Löscher W. The novel dual-mechanism Kv7 potassium channel/TSPO receptor activator GRT-X is more effective than the Kv7 channel opener retigabine in the 6-Hz refractory seizure mouse model. Neuropharmacology 2022; 203:108884. [PMID: 34785163 DOI: 10.1016/j.neuropharm.2021.108884] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 11/09/2021] [Accepted: 11/10/2021] [Indexed: 12/16/2022]
Abstract
Epilepsy, one of the most common and most disabling neurological disorders, is characterized by spontaneous recurrent seizures, often associated with structural brain alterations and cognitive and psychiatric comorbidities. In about 30% of patients, the seizures are resistant to current treatments; so more effective treatments are urgently needed. Among the ∼30 clinically approved antiseizure drugs, retigabine (ezogabine) is the only drug that acts as a positive allosteric modulator (or opener) of voltage-gated Kv7 potassium channels, which is particularly interesting for some genetic forms of epilepsy. Here we describe a novel dual-mode-of-action compound, GRT-X (N-[(3-fluorophenyl)-methyl]-1-(2-methoxyethyl)-4-methyl-2-oxo-(7-trifluoromethyl)-1H-quinoline-3-carboxylic acid amide) that activates both Kv7 potassium channels and the mitochondrial translocator protein 18 kDa (TSPO), leading to increased synthesis of brain neurosteroids. TSPO activators are known to exert anti-inflammatory, neuroprotective, anxiolytic, and antidepressive effects, which, together with an antiseizure effect (mediated by Kv7 channels), would be highly relevant for the treatment of epilepsy. This prompted us to compare the antiseizure efficacy of retigabine and GRT-X in six mouse and rat models of epileptic seizures, including the 6-Hz model of difficult-to-treat focal seizures. Furthermore, the tolerability of the two compounds was compared in mice and rats. Potency comparisons were based on both doses and peak plasma concentrations. Overall, GRT-X was more effective than retigabine in three of the six seizure models used here, the most important difference being the high efficacy in the 6-Hz (32 mA) seizure model in mice. Based on drug plasma levels, GRT-X was at least 30 times more potent than retigabine in the latter model. These data indicate that GRT-X is a highly interesting novel anti-seizure drug with a unique (first-in-class) dual-mode mechanism of action.
Collapse
Affiliation(s)
| | - Marion Bankstahl
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | - Jens Bankstahl
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany
| | | | | | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany.
| |
Collapse
|
6
|
Hotta N, Miyamoto M, Suzuki K. Lamotrigine and retigabine increase motor threshold in transcranial magnetic stimulation at the dose required to produce an antiepileptic effect against maximal electroshock-induced seizure in rats. Neurosci Lett 2022; 771:136460. [PMID: 35051437 DOI: 10.1016/j.neulet.2022.136460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 01/07/2022] [Accepted: 01/11/2022] [Indexed: 10/19/2022]
Abstract
Transcranial magnetic stimulation (TMS) is a neurophysiological technique that enables noninvasive evaluation of neuronal excitability in the brain. In the past, a large number of antiepileptic drugs were shown to increase the motor threshold (MT) in clinical TMS studies, suggesting the inhibition of excessive neuronal excitability. To facilitate drug development, the confirmation of similar changes in neurophysiological biomarkers in both preclinical and clinical studies is crucial; however, until now, there have been no data showing the drug efficacies on neuronal excitabilities as measured using TMS in rodents. In this study, we found that the antiepileptic drugs, lamotrigine (10 mg/kg) and retigabine (5 mg/kg), significantly increased the MT in rats using TMS, which is similar to clinical study findings. In addition, we demonstrated that these drugs could inhibit maximal electroshock (MES)-induced seizures in rats when given at the same dose required to be effective in the TMS experiment. These findings suggest that the effects of antiepileptic drugs in our rat TMS system have a similar sensitivity to that of the antiepileptic effects in rats with MES-induced seizures. The measurement of MT in a TMS study may be a noninvasive translational approach for predicting antiepileptic efficacy in drug development.
Collapse
Affiliation(s)
- Natsu Hotta
- Neuroscience Drug Discovery Unit, Research, Takeda Pharmaceutical Company Limited
| | - Maki Miyamoto
- Drug Metabolism and Pharmacokinetics Research Laboratories, Research, Takeda Pharmaceutical Company Limited
| | - Kazunori Suzuki
- Neuroscience Drug Discovery Unit, Research, Takeda Pharmaceutical Company Limited.
| |
Collapse
|
7
|
Design, synthesis and evaluation of substituted piperidine based KCNQ openers as novel antiepileptic agents. Bioorg Med Chem Lett 2018; 28:1731-1735. [PMID: 29706422 DOI: 10.1016/j.bmcl.2018.04.040] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 03/30/2018] [Accepted: 04/14/2018] [Indexed: 12/31/2022]
Abstract
Epilepsy is a kind of disease with complicated pathogenesis. KCNQ (Kv7) is a voltage dependent potassium channel that is mostly associated with epilepsy and thus becomes an important target in the treatment of epilepsy. In this paper, a series of substituted piperidine derivatives targeting KCNQ were designed and synthesized by using scaffold hopping and active substructure hybridization. Compounds were evaluated by fluorescence-based thallium influx assay, Rb+ flow assay and electrophysiological patch-clamp assay. Results showed that some compounds possessed more potent potassium channel opening activity than Retigabine. More significantly, compound 11 was found to have good pharmacokinetic profiles in vivo.
Collapse
|
8
|
Franco V, Baruffi K, Gatti G, Marchiselli R, Fattore C, Canevini MP, Crema F, Perucca E. A simple and rapid HPLC-UV method for the determination of retigabine in human plasma. Biomed Chromatogr 2018; 32:e4168. [DOI: 10.1002/bmc.4168] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 11/26/2017] [Accepted: 12/04/2017] [Indexed: 11/07/2022]
Affiliation(s)
- Valentina Franco
- Clinical and Experimental Pharmacology Unit, Department of Internal Medicine and Therapeutics; University of Pavia; Pavia Italy
| | - Katia Baruffi
- Clinical and Experimental Pharmacology Unit, Department of Internal Medicine and Therapeutics; University of Pavia; Pavia Italy
| | - Giuliana Gatti
- Clinical and Experimental Pharmacology Unit, Department of Internal Medicine and Therapeutics; University of Pavia; Pavia Italy
| | - Roberto Marchiselli
- Clinical and Experimental Pharmacology Unit, Department of Internal Medicine and Therapeutics; University of Pavia; Pavia Italy
| | | | - Maria Paola Canevini
- Epilepsy Center; San Paolo Hospital; Milan Italy
- Department of Health Sciences; Università degli Studi di Milano; Italy
| | - Francesca Crema
- Clinical and Experimental Pharmacology Unit, Department of Internal Medicine and Therapeutics; University of Pavia; Pavia Italy
| | - Emilio Perucca
- Clinical and Experimental Pharmacology Unit, Department of Internal Medicine and Therapeutics; University of Pavia; Pavia Italy
- IRCCS Mondino Foundation; Pavia
| |
Collapse
|
9
|
Bhati A, Desai RP, Ramchand C. Enhancement in recovery of drugs with high protein binding efficiency from human plasma using magnetic nanoparticles. J Pharm Biomed Anal 2017. [DOI: 10.1016/j.jpba.2017.06.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
10
|
LaPenna P, Tormoehlen LM. The Pharmacology and Toxicology of Third-Generation Anticonvulsant Drugs. J Med Toxicol 2017; 13:329-342. [PMID: 28815428 DOI: 10.1007/s13181-017-0626-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 07/09/2017] [Accepted: 07/12/2017] [Indexed: 10/19/2022] Open
Abstract
Epilepsy is a neurologic disorder affecting approximately 50 million people worldwide, or about 0.7% of the population [1]. Thus, the use of anticonvulsant drugs in the treatment of epilepsy is common and widespread. There are three generations of anticonvulsant drugs, categorized by the year in which they were developed and released. The aim of this review is to discuss the pharmacokinetics, drug-drug interactions, and adverse events of the third generation of anticonvulsant drugs. Where available, overdose data will be included. The pharmacokinetic properties of third-generation anticonvulsant drugs include relatively fewer drug-drug interactions, as well as several unique and life-threatening adverse events. Overdose data are limited, so thorough review of adverse events and knowledge of drug mechanism will guide expectant management of future overdose cases. Reporting of these cases as they occur will be necessary to further clarify toxicity of these drugs.
Collapse
Affiliation(s)
- Paul LaPenna
- Department of Neurology, Indiana University, 355 W. 16th Street, Suite 3200, Indianapolis, IN, 46202, USA
| | - Laura M Tormoehlen
- Department of Neurology, Indiana University, 355 W. 16th Street, Suite 3200, Indianapolis, IN, 46202, USA. .,Department of Emergency Medicine, Indiana University, Indianapolis, IN, USA.
| |
Collapse
|
11
|
Rubi L, Kovar M, Zebedin-Brandl E, Koenig X, Dominguez-Rodriguez M, Todt H, Kubista H, Boehm S, Hilber K. Modulation of the heart's electrical properties by the anticonvulsant drug retigabine. Toxicol Appl Pharmacol 2017. [PMID: 28641963 DOI: 10.1016/j.taap.2017.06.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Retigabine, currently used as antiepileptic drug, has a wide range of potential medical uses. Administration of the drug in patients can lead to QT interval prolongation in the electrocardiogram and to cardiac arrhythmias in rare cases. This suggests that the drug may perturb the electrical properties of the heart, and the underlying mechanisms were investigated here. Effects of retigabine on currents through human cardiac ion channels, heterologously expressed in tsA-201 cells, were studied in whole-cell patch-clamp experiments. In addition, the drug's impact on the cardiac action potential was tested. This was done using ventricular cardiomyocytes isolated from Langendorff-perfused guinea pig hearts and cardiomyocytes derived from human induced pluripotent stem cells. Further, to unravel potential indirect effects of retigabine on the heart which might involve the autonomic nervous system, membrane potential and noradrenaline release from sympathetic ganglionic neurons were measured in the absence and presence of the drug. Retigabine significantly inhibited currents through hKv11.1 potassium, hNav1.5 sodium, as well as hCav1.2 calcium channels, but only in supra-therapeutic concentrations. In a similar concentration range, the drug shortened the action potential in both guinea pig and human cardiomyocytes. Therapeutic concentrations of retigabine, on the other hand, were sufficient to inhibit the activity of sympathetic ganglionic neurons. We conclude that retigabine- induced QT interval prolongation, and the reported cases of cardiac arrhythmias after application of the drug in a typical daily dose range, cannot be explained by a direct modulatory effect on cardiac ion channels. They are rather mediated by indirect actions at the level of the autonomic nervous system.
Collapse
Affiliation(s)
- Lena Rubi
- Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Michael Kovar
- Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Eva Zebedin-Brandl
- Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Xaver Koenig
- Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Manuel Dominguez-Rodriguez
- Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Hannes Todt
- Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Helmut Kubista
- Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Stefan Boehm
- Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, Vienna, Austria.
| | - Karlheinz Hilber
- Center for Physiology and Pharmacology, Department of Neurophysiology and Pharmacology, Medical University of Vienna, Vienna, Austria.
| |
Collapse
|
12
|
Nassoiy SP, Byron KL, Majetschak M. Kv7 voltage-activated potassium channel inhibitors reduce fluid resuscitation requirements after hemorrhagic shock in rats. J Biomed Sci 2017; 24:8. [PMID: 28095830 PMCID: PMC5240358 DOI: 10.1186/s12929-017-0316-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 01/10/2017] [Indexed: 12/24/2022] Open
Abstract
Background Recent evidence suggests that drugs targeting Kv7 channels could be used to modulate vascular function and blood pressure. Here, we studied whether Kv7 channel inhibitors can be utilized to stabilize hemodynamics and reduce resuscitation fluid requirements after hemorrhagic shock. Methods Anesthetized male Sprague-Dawley rats were instrumented with arterial and venous catheters for blood pressure monitoring, hemorrhage and fluid resuscitation. Series 1: Linopirdine (Kv7 channel blocker, 0.1–6 mg/kg) or retigabine (Kv7 channel activator, 0.1–12 mg/kg) were administered to normal animals. Series 2: Animals were hemorrhaged to a MAP of 25 mmHg for 30 min, followed by fluid resuscitation with normal saline (NS) to a MAP of 70 mmHg until t = 75 min. Animals were treated with single bolus injections of vehicle, linopirdine (1–6 mg/kg), XE-991 (structural analogue of linopirdine with higher potency for channel blockade, 1 mg/kg) prior to fluid resuscitation. Series 3: Animals were resuscitated with NS alone or NS supplemented with linopirdine (1.25–200 μg/mL). Data were analyzed with 2-way ANOVA/Bonferroni post-hoc testing. Results Series 1: Linopirdine transiently (10–15 min) and dose-dependently increased MAP by up to 15%. Retigabine dose-dependently reduced MAP by up to 60%, which could be reverted with linopirdine. Series 2: Fluid requirements to maintain MAP at 70 mmHg were 65 ± 34 mL/kg with vehicle, and 57 ± 13 mL/kg, 22 ± 8 mL/kg and 22 ± 11 mL/kg with intravenous bolus injection of 1, 3 and 6 mg/kg linopirdine, respectively. XE-991 (1 mg/kg), reduced resuscitation requirements comparable to 3 mg/kg linopirdine. Series 3: When resuscitation was performed with linopirdine-supplemented normal saline (NS), fluid requirements to stabilize MAP were 73 ± 12 mL/kg with NS alone and 72 ± 24, 61 ± 20, 36 ± 9 and 31 ± 9 mL/kg with NS supplemented with 1.25, 6.25, 12.5 and 200 μg/mL linopirdine, respectively. Conclusions Our data suggest that Kv7 channel blockers could be used to stabilize blood pressure and reduce fluid resuscitation requirements after hemorrhagic shock.
Collapse
Affiliation(s)
- Sean P Nassoiy
- Burn and Shock Trauma Research Institute, Department of Surgery, Loyola University Chicago, Stritch School of Medicine, 2160 S. 1st Avenue, Maywood, IL, 60153, USA
| | - Kenneth L Byron
- Department of Molecular Pharmacology and Therapeutics, Loyola University Chicago, Stritch School of Medicine, 2160 S. 1st Avenue, Maywood, IL, 60153, USA
| | - Matthias Majetschak
- Burn and Shock Trauma Research Institute, Department of Surgery, Loyola University Chicago, Stritch School of Medicine, 2160 S. 1st Avenue, Maywood, IL, 60153, USA. .,Department of Molecular Pharmacology and Therapeutics, Loyola University Chicago, Stritch School of Medicine, 2160 S. 1st Avenue, Maywood, IL, 60153, USA.
| |
Collapse
|
13
|
Rudzinski LA, Vélez-Ruiz NJ, Gedzelman ER, Mauricio EA, Shih JJ, Karakis I. New antiepileptic drugs: focus on ezogabine, clobazam, and perampanel. J Investig Med 2016; 64:1087-101. [DOI: 10.1136/jim-2016-000151] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/12/2016] [Indexed: 12/17/2022]
Abstract
Ezogabine, clobazam, and perampanel are among the newest antiseizure drugs approved by the Food and Drug Administration between 2011 and 2012. Ezogabine and perampanel are approved for adjunctive treatment of partial epilepsy. Perampanel is also approved for adjunctive treatment of primary generalized tonic–clonic seizures. Ezogabine and perampanel have novel mechanisms of action. Ezogabine binds to voltage-gated potassium channels and increases the M-current thereby causing membrane hyperpolarization. Perampanel is a selective, non-competitive 2-amino-3-(3-hydroxy-5-methyl-isoxazol-4-yl)propanoic acid receptor antagonist, which reduces neuronal excitation. Clobazam has been used worldwide since the 1970s and is approved for adjunctive treatment of seizures associated with Lennox-Gastaut syndrome. Clobazam is the only 1,5-benzodiazepine currently in clinical use, which is less sedating than the commonly used 1,4-benzodiazepines. Phase III multicenter, randomized, double-blind, placebo-controlled trials demonstrated efficacy and good tolerability of these 3 new antiepileptic drugs. These drugs represent a welcome addition to the armamentarium of practitioners, but it remains to be seen how they will affect the landscape of pharmacoresistant epilepsy.
Collapse
|
14
|
Dried blood spots for monitoring and individualization of antiepileptic drug treatment. Eur J Pharm Sci 2015; 75:25-39. [DOI: 10.1016/j.ejps.2015.04.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 04/08/2015] [Accepted: 04/09/2015] [Indexed: 11/21/2022]
|
15
|
Treven M, Koenig X, Assadpour E, Gantumur E, Meyer C, Hilber K, Boehm S, Kubista H. The anticonvulsant retigabine is a subtype selective modulator of GABAA receptors. Epilepsia 2015; 56:647-57. [PMID: 25779225 PMCID: PMC4949651 DOI: 10.1111/epi.12950] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/30/2015] [Indexed: 01/17/2023]
Abstract
OBJECTIVE Within its range of therapeutic plasma concentrations, the anticonvulsant retigabine (ezogabine) is believed to selectively act on Kv7 channels. Here, the contribution of specific γ-aminobutyric acid (GABA)A receptor subtypes to the antiseizure effects of retigabine was investigated. METHODS Using patch-clamp recordings, seizure-like activity, tonic currents, and GABA-induced currents in hippocampal neurons were tested for their sensitivity toward retigabine, as were recombinant GABAA receptors expressed in tsA 201 cells. RESULTS Retigabine reduced seizure-like activity elicited by low Mg(2+) in a concentration-dependent manner with half maximal inhibition at 1 μm. Seizure-like activity triggered by blocking either Kv7 channels or GABAA receptors was equally reduced by retigabine, but when these channels/receptors were blocked simultaneously, the inhibition was lost. Retigabine (10 μm) enhanced bicuculline-sensitive tonic currents in hippocampal neurons, but failed to affect GABA-evoked currents. However, when receptors involved in phasic GABAergic inhibition were blocked by penicillin, retigabine did enhance GABA-evoked currents. In tsA 201 cells expressing various combinations of GABAA receptor subunits, 10 μm retigabine enhanced currents through α1β2δ, α4β2δ, α4β3δ, and α6β2δ receptors, but left currents through α1β2γ2S, α4β3γ2S, α5β3γ2S, and α6β2γ2S receptors unaltered. With αβ receptors, retigabine diminished currents through α1β2 and α4β3, but increased currents through α6β2 receptors. The enhancement of currents through α1β2δ receptors by retigabine was concentration dependent and became significant at 1 μm. SIGNIFICANCE These results demonstrate that retigabine is a subtype selective modulator of GABAA receptors with preference for extrasynaptic δ-containing receptors; this property may contribute to its broad antiepileptic effectiveness and explain its lack of effect on absence seizures.
Collapse
Affiliation(s)
- Marco Treven
- Department of Neurophysiology and Neuropharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | | | | | | | | | | | | | | |
Collapse
|
16
|
Tompson DJ, Crean CS, Buraglio M, Arumugham T. Lack of effect of ezogabine/retigabine on the pharmacokinetics of digoxin in healthy individuals: results from a drug-drug interaction study. Clin Pharmacol 2014; 6:149-59. [PMID: 25342921 PMCID: PMC4206209 DOI: 10.2147/cpaa.s64131] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Introduction The potential for ezogabine/retigabine (EZG/RTG) and its N-acetyl metabolite (NAMR) to inhibit the transporter protein P-glycoprotein-(P-gp)-mediated digoxin transport was tested in vitro. EZG/RTG did not inhibit P-gp. However, NAMR inhibited P-gp in a concentration-dependent manner. Based on these in vitro results, NAMR had the potential to inhibit P-gp at therapeutic doses of EZG/RTG (600–1,200 mg/day). As digoxin has a narrow therapeutic index, inhibition of digoxin clearance may have an impact on its safety. Methods An open-label, single-center, two session, fixed-sequence study was conducted to assess the effect of co-administration of therapeutic doses of EZG/RTG on digoxin pharmacokinetics in healthy adults. In session 1, subjects received a single dose of digoxin 0.25 mg. In session 2, EZG/RTG was up-titrated over 6 weeks. Digoxin 0.25 mg was co-administered at EZG/RTG steady-state doses of 600, 900, and, based on tolerability, 1,050/1,200 mg/day. Blood samples were collected over 144 hours for determination of digoxin, EZG/RTG, and NAMR concentrations. Urine samples were collected over 48 hours for determination of digoxin concentrations. Results Of 30 subjects enrolled, 29 were included in the pharmacokinetic analysis. Compared with digoxin alone, co-administration with EZG/RTG led to small increases in the digoxin plasma area under the concentration–time curve (AUC)0–120 at doses of 600, 900, and 1,050/1,200 mg (geometric mean ratio 1.08, 90% confidence interval [CI] 1.01–1.15; 1.18, 90% CI 1.10–1.27; 1.13, 90% CI 1.05–1.21, respectively). Safety was consistent with previous repeat-dose studies of EZG/RTG in healthy subjects. Conclusion Co-administration of EZG/RTG across the therapeutic range resulted in small, non-dose-dependent and non-clinically relevant increases in digoxin systemic exposure, suggesting that digoxin dose adjustment is not necessary.
Collapse
Affiliation(s)
- Debra J Tompson
- Clinical Pharmacology Modelling and Simulation, GlaxoSmithKline, Stevenage, Hertfordshire, UK
| | - Christopher S Crean
- Clinical Pharmacology and Pharmacokinetics, Valeant Pharmaceuticals North America, Durham, NC, USA
| | - Mauro Buraglio
- Clinical Pharmacology Modelling and Simulation, GlaxoSmithKline, Stevenage, Hertfordshire, UK
| | | |
Collapse
|
17
|
Zhang D, Song X, Su J. Isolation, identification and structure elucidation of two novel process-related impurities of retigabine. J Pharm Biomed Anal 2014; 99:22-7. [DOI: 10.1016/j.jpba.2014.06.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 06/12/2014] [Accepted: 06/14/2014] [Indexed: 10/25/2022]
|
18
|
Fretwell LV, Woolard J. Cardiovascular responses to retigabine in conscious rats--under normotensive and hypertensive conditions. Br J Pharmacol 2014; 169:1279-89. [PMID: 23581476 DOI: 10.1111/bph.12203] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Revised: 03/08/2013] [Accepted: 03/22/2013] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND AND PURPOSE Retigabine is a recently approved antiepileptic agent which activates Kv7.2-7.5 potassium channels. It is emerging that these channels have an important role in vascular regulation, but the vascular effects of retigabine in the conscious state are unknown. Hence, in the present study we assessed the regional haemodynamic responses to retigabine in conscious rats. EXPERIMENTAL APPROACH Male Sprague Dawley rats were chronically instrumented with pulsed Doppler flow probes to measure regional haemodynamic responses to retigabine under control conditions and during acute hypertension induced by infusion of angiotensin II and arginine vasopressin. Further experiments were performed, using the β-adrenoceptor antagonists CGP 20712A, ICI 118551 and propranolol, to elucidate the roles of β-adrenoceptors in the responses to retigabine in vivo and in vitro. KEY RESULTS Under normotensive conditions, retigabine induced dose-dependent hypotension and hindquarters vasodilatation, with small, transient renal and mesenteric vasodilatations. In the acutely hypertensive state, the renal and mesenteric, but not hindquarters, vasodilatations were enhanced. The response of the hindquarters vascular bed to retigabine was mediated, in part, by β₂-adrenoceptors. However, in vitro experiments confirmed that retigabine did not act as a β-adrenoceptor agonist. CONCLUSIONS AND IMPLICATIONS We demonstrated that retigabine causes regionally specific vasodilatations, which are different under normotensive and hypertensive conditions, and are, in part, mediated by β₂-adrenoceptors in some vascular beds but not in others. These results broadly support previous findings and further indicate that Kv7 channels are a potential therapeutic target for the treatment of vascular diseases associated with inappropriate vasoconstriction.
Collapse
Affiliation(s)
- L V Fretwell
- Institute of Cell Signalling, Medical School, Queen's Medical Centre, University of Nottingham, Nottingham, UK
| | | |
Collapse
|
19
|
Retigabine calms seizure-induced behavior following status epilepticus. Epilepsy Behav 2014; 37:123-32. [PMID: 25016241 DOI: 10.1016/j.yebeh.2014.06.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 05/28/2014] [Accepted: 06/07/2014] [Indexed: 12/30/2022]
Abstract
In adult rats, intraperitoneal injection of kainate (KA) results in sustained status epilepticus and persistent behavioral comorbidities such as hyperexcitability, anxiety, and altered response to environmental cues. Intrahippocampal KA also results in sustained status epilepticus and continuous high frequency oscillations in the electroencephalograph (EEG), although subsequent behavioral side effects are unknown. We hypothesized that retigabine, a recently discovered anticonvulsant and potent positive modulator of Kv7 channels, may attenuate seizure-induced behavioral abnormalities. Status epilepticus was induced by administration of KA either intraperitoneally (15 mg/kg) or by single intrahippocampal injection (1.0 μg/0.5 μL). After 24 h, half of systemically KA-treated animals that reached stage 6 seizures were injected once daily with retigabine (5 mg/kg) for 14 continuous days. All groups underwent three behavioral tests--capture and handling, open field, and elevated plus maze--24 h following the last retigabine treatment and were sacrificed at 25-28 days. In the capture and handling test, systemic KA treatment resulted in frisky behavior and resistance to capture with wild attempts to escape during the 1st, 2nd, and 3rd weeks of the observation period. In contrast, these behaviors were attenuated in KA+retigabine-treated animals. In the open-field test, KA-treated animals spent more time in the center zone, but KA+retigabine-treated rats had greater overall activity compared with those having vehicle, KA, or retigabine-only treatment. In the elevated plus maze, KA+retigabine-treated animals traveled greater distances in open and closed arms (proximal and distal) compared with controls, also signifying anxiety reduction. Retigabine-only-treated rats traveled more in the open proximal arms compared with controls, indicating increased hyperlocomotion in normotensive rats. Although treatment with KA+retigabine resulted in anxiolytic-like effects in all three behavioral tasks compared with vehicle, this group did not significantly differ from systemically KA-treated rats in most measurements in open-field and elevated plus maze tasks, suggesting that retigabine may also cause hyperlocomotion unrelated to anxiety level. Despite that intrahippocampal KA-treated rats displayed comparable seizure behavior, epileptiform activity, and hippocampal injury, their behavior resembled the controls, suggesting that molecular and subsequent cellular changes are also partially responsible for anxiolytic-like effects and that these results are likely independent of the hippocampus.
Collapse
|
20
|
Krasowski MD, McMillin GA. Advances in anti-epileptic drug testing. Clin Chim Acta 2014; 436:224-36. [PMID: 24925169 DOI: 10.1016/j.cca.2014.06.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 05/29/2014] [Accepted: 06/03/2014] [Indexed: 12/12/2022]
Abstract
In the past twenty-one years, 17 new antiepileptic drugs have been approved for use in the United States and/or Europe. These drugs are clobazam, ezogabine (retigabine), eslicarbazepine acetate, felbamate, gabapentin, lacosamide, lamotrigine, levetiracetam, oxcarbazepine, perampanel, pregabalin, rufinamide, stiripentol, tiagabine, topiramate, vigabatrin and zonisamide. Therapeutic drug monitoring is often used in the clinical dosing of the newer anti-epileptic drugs. The drugs with the best justifications for drug monitoring are lamotrigine, levetiracetam, oxcarbazepine, stiripentol, and zonisamide. Perampanel, stiripentol and tiagabine are strongly bound to serum proteins and are candidates for monitoring of the free drug fractions. Alternative specimens for therapeutic drug monitoring are saliva and dried blood spots. Therapeutic drug monitoring of the new antiepileptic drugs is discussed here for managing patients with epilepsy.
Collapse
Affiliation(s)
- Matthew D Krasowski
- Department of Pathology, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, United States.
| | - Gwendolyn A McMillin
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, United States; ARUP Institute for Clinical and Experimental Pathology, ARUP Laboratories Inc., Salt Lake City, UT, United States
| |
Collapse
|
21
|
Douša M, Srbek J, Rádl S, Cerný J, Klecán O, Havlíček J, Tkadlecová M, Pekárek T, Gibala P, Nováková L. Identification, characterization, synthesis and HPLC quantification of new process-related impurities and degradation products in retigabine. J Pharm Biomed Anal 2014; 94:71-6. [PMID: 24552644 DOI: 10.1016/j.jpba.2014.01.042] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 01/23/2014] [Accepted: 01/26/2014] [Indexed: 01/07/2023]
Abstract
Two new impurities were described and determined using gradient HPLC method with UV detection in retigabine (RET). Using LC-HRMS, NMR and IR analysis the impurities were identified as RET-dimer I: diethyl {4,4'-diamino-6,6'-bis[(4-fluorobenzyl)amino]biphenyl-3,3'-diyl}biscarbamate and RET-dimer II: ethyl {2-amino-5-[{2-amino-4-[(4-fluorobenzyl) amino] phenyl} (ethoxycarbonyl) amino]-4-[(4-fluorobenzyl)amino] phenyl}carbamate. Reference standards of these impurities were synthesized followed by semipreparative HPLC purification. The mechanism of the formation of these impurities is also discussed. An HPLC method was optimized in order to separate, selectively detect and quantify all process-related impurities and degradation products of RET. The presented method, which was validated in terms of linearity, limit of detection (LOD), limit of quantification (LOQ) and selectivity is very quick (less than 11min including re-equilibration time) and therefore highly suitable for routine analysis of RET related substances as well as stability studies.
Collapse
Affiliation(s)
- Michal Douša
- Zentiva, k.s. Praha, U Kabelovny 130, 102 37 Praha 10, Czech Republic.
| | - Jan Srbek
- Zentiva, k.s. Praha, U Kabelovny 130, 102 37 Praha 10, Czech Republic
| | - Stanislav Rádl
- Zentiva, k.s. Praha, U Kabelovny 130, 102 37 Praha 10, Czech Republic
| | - Josef Cerný
- Zentiva, k.s. Praha, U Kabelovny 130, 102 37 Praha 10, Czech Republic
| | - Ondřej Klecán
- Zentiva, k.s. Praha, U Kabelovny 130, 102 37 Praha 10, Czech Republic
| | - Jaroslav Havlíček
- Zentiva, k.s. Praha, U Kabelovny 130, 102 37 Praha 10, Czech Republic
| | | | - Tomáš Pekárek
- Zentiva, k.s. Praha, U Kabelovny 130, 102 37 Praha 10, Czech Republic
| | - Petr Gibala
- Zentiva, k.s. Praha, U Kabelovny 130, 102 37 Praha 10, Czech Republic
| | - Lucie Nováková
- Department of Analytical Chemistry, Charles University, Faculty of Pharmacy, Heyrovského 1203, 500 05 Hradec Králové, Czech Republic
| |
Collapse
|
22
|
|
23
|
Splinter MY. Efficacy of retigabine in adjunctive treatment of partial onset seizures in adults. J Cent Nerv Syst Dis 2013; 5:31-41. [PMID: 24250245 PMCID: PMC3825677 DOI: 10.4137/jcnsd.s9299] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Objective To evaluate efficacy and tolerability of retigabine (ezogabine, US adopted name) in the adjunctive treatment of partial-onset seizures in adults. Retigabine is the first anticonvulsant in its class, decreasing neuronal excitability by opening voltage-gated potassium channels. Methods MEDLINE and EMBASE were systematically searched using search terms retigabine and ezogabine for randomized controlled trials published from 1980 through August 17, 2013. Additionally, articles relating to pharmacology, pharmacokinetics, tolerability and interactions were examined for inclusion. Published abstracts and websites of the Food and Drug Administration and European Medication Agency were reviewed for additional relevant information. Results One phase IIb and two phase III trials were identified. Retigabine has been reported to have dose dependent efficacy in adjunctive treatment of resistant partial-onset seizures in adults in doses of 600, 900 and 1200 mg/day. Similar to other anticonvulsants, the most common adverse events were central nervous system related. Retigabine has several unique adverse events compared to other anticonvulsants: urinary retention and, with extended use, pigment changes to the skin and retina. Retigabine is metabolized by glucuronidation and acetylation. There are few drug interactions with retigabine. Conclusions Retigabine has been shown to have efficacy when used as adjunctive therapy in partial-onset seizures. It has a novel mechanism of action, activation of voltage-gated potassium channels. It has less drug interactions than many other anticonvulsants because it is not metabolized through the P-450 system. Its place in therapy has yet to be determined, especially with recent reports of pigment discoloration of skin and the retina with extended use.
Collapse
Affiliation(s)
- Michele Y Splinter
- University of Oklahoma Health Sciences Center, College of Pharmacy, Department of Pharmacy: Clinical and Administrative Sciences, Oklahoma City, OK
| |
Collapse
|
24
|
Abstract
Blood (serum/plasma) antiepileptic drug (AED) therapeutic drug monitoring (TDM) has proven to be an invaluable surrogate marker for individualizing and optimizing the drug management of patients with epilepsy. Since 1989, there has been an exponential increase in AEDs with 23 currently licensed for clinical use, and recently, there has been renewed and extensive interest in the use of saliva as an alternative matrix for AED TDM. The advantages of saliva include the fact that for many AEDs it reflects the free (pharmacologically active) concentration in serum; it is readily sampled, can be sampled repetitively, and sampling is noninvasive; does not require the expertise of a phlebotomist; and is preferred by many patients, particularly children and the elderly. For each AED, this review summarizes the key pharmacokinetic characteristics relevant to the practice of TDM, discusses the use of other biological matrices with particular emphasis on saliva and the evidence that saliva concentration reflects those in serum. Also discussed are the indications for salivary AED TDM, the key factors to consider when saliva sampling is to be undertaken, and finally, a practical protocol is described so as to enable AED TDM to be applied optimally and effectively in the clinical setting. Overall, there is compelling evidence that salivary TDM can be usefully applied so as to optimize the treatment of epilepsy with carbamazepine, clobazam, ethosuximide, gabapentin, lacosamide, lamotrigine, levetiracetam, oxcarbazepine, phenobarbital, phenytoin, primidone, topiramate, and zonisamide. Salivary TDM of valproic acid is probably not helpful, whereas for clonazepam, eslicarbazepine acetate, felbamate, pregabalin, retigabine, rufinamide, stiripentol, tiagabine, and vigabatrin, the data are sparse or nonexistent.
Collapse
|
25
|
Tompson DJ, Crean CS, Reeve R, Berry NS. Efficacy and tolerability exposure-response relationship of retigabine (ezogabine) immediate-release tablets in patients with partial-onset seizures. Clin Ther 2013; 35:1174-1185.e4. [PMID: 23916044 DOI: 10.1016/j.clinthera.2013.06.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 06/14/2013] [Accepted: 06/15/2013] [Indexed: 12/31/2022]
Abstract
BACKGROUND Retigabine (international nonproprietary name)/ezogabine (United States adopted name) is an antiepileptic drug (AED) that enhances KCNQ (Kv7) potassium channel activity. OBJECTIVES The aim of this study was to explore the relationship between retigabine/ezogabine systemic exposure and efficacy and adverse events (AEs) of retigabine/ezogabine from Phase III clinical trials. METHODS Data were combined from Studies 301 and 302, which were both randomized, double-blind, placebo-controlled, multicenter, parallel-group studies with similar inclusion and exclusion criteria. All patients had partial-onset seizures and were receiving 1 to 3 concomitant AEDs. Systemic exposure was predicted for each patient as the average steady-state AUC0-τ during the 12-week maintenance phase, based on a population pharmacokinetic model developed for retigabine/ezogabine. Efficacy end points included reduction in total partial-seizure frequency from baseline and probability of ≥50% reduction from baseline in seizure frequency. The probabilities of occurrence of 6 AEs were also evaluated. RESULTS AUC0-τ values increased linearly over the 600- to 1200-mg/d dose range. Over the entire AUC0-τ range, the probability of efficacy was greater than that for any AE. The slopes of the exposure-response relationship for probability of dizziness and abnormal coordination were similar to that for efficacy, whereas the slopes for dysarthria, somnolence, tremor, and blurred vision were shallower, indicating that the probability of these events occurring was less affected than the probability of efficacy by increases in retigabine/ezogabine AUC0-τ. CONCLUSIONS Based on the summary statistics of pharmacokinetic parameters, systemic exposure to retigabine/ezogabine increased linearly with dose (600-1200 mg/d). Population pharmacokinetics and pharmacodynamics showed that the probability of efficacy and AEs increased with increasing systemic retigabine/ezogabine exposure, and the probability of efficacy was higher than the probability of any of the AEs. The 35%-50% between-patient variability and overlap between retigabine/ezogabine dose levels in AUC0-τ values indicate that, as with other AEDs, doses should be individually titrated based on a balance between efficacy and tolerability.
Collapse
|
26
|
Zhang X, Jakubowski M, Buettner C, Kainz V, Gold M, Burstein R. Ezogabine (KCNQ2/3 channel opener) prevents delayed activation of meningeal nociceptors if given before but not after the occurrence of cortical spreading depression. Epilepsy Behav 2013; 28:243-8. [PMID: 23562239 PMCID: PMC3700644 DOI: 10.1016/j.yebeh.2013.02.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 02/25/2013] [Accepted: 02/27/2013] [Indexed: 10/27/2022]
Abstract
We proposed recently that induction of delayed activation of trigeminovascular neurons by cortical spreading depression (CSD) can explain the delayed onset of headache after the migraine aura ("aura"). This prompted us to search for ways to block the neuronal activation by CSD - a preclinical correlate of an attempt to find a drug that can block the initiation of headache when administered shortly after onset of aura (i.e., preemptively). Because migraine headache and epileptic seizures are comorbid chronic neurological disorders characterized by hyperexcitable brain networks, we began the search for such goal with an M-type potassium channel opener. We opted to use ezogabine, recently approved by the FDA as adjunctive treatment of partial onset seizures in adults, because it is a selective KCNQ2/3 channel opener. When CSD was induced before ezogabine injection (8.25 mg/kg, i.p.), 40% (6/15) of the units doubled their firing rate about 45 min later for about 95 min. Similarly, when CSD was induced before vehicle was injected (4% DMSO, 0.5% methylcellulose), 50% (3/6) of the units doubled their firing rate about 30 min later for about 120 min. When CSD was triggered 1h after ezogabine injection, it activated only 8% of the units. By itself, ezogabine injection resulted in a 30% attenuation of ongoing firing in all 10 control units. Thus, activation of KCNQ2/3 channels during the aura is unlikely to preempt the onset of headache but may reduce the incidence of migraine if given during prodromes that precede the headache by hours. Given the mechanistic similarities between migraine aura and epileptic seizures, it may be worthwhile to determine whether preemptive administration of ezogabine can prevent oncoming seizures in patients whose warning signs precede their seizures by more than an hour.
Collapse
Affiliation(s)
- XiChun Zhang
- Department of Anesthesia and Critical Care, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston MA 02215
| | - Moshe Jakubowski
- Department of Anesthesia and Critical Care, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston MA 02215
| | - Catherine Buettner
- Division of General Medicine and Primary Care, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston MA 02215
| | - Vanessa Kainz
- Department of Anesthesia and Critical Care, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston MA 02215
| | - Michael Gold
- Department of Anesthesiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 05213
| | - Rami Burstein
- Department of Anesthesia and Critical Care, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston MA 02215
| |
Collapse
|
27
|
The effects of ethanol on the pharmacokinetics, pharmacodynamics, safety, and tolerability of ezogabine (retigabine). Clin Ther 2013; 35:87-93. [PMID: 23328270 DOI: 10.1016/j.clinthera.2012.12.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Revised: 12/07/2012] [Accepted: 12/12/2012] [Indexed: 10/27/2022]
Abstract
BACKGROUND The antiepileptic drug ezogabine (EZG; US adopted name for retigabine [the international nonproprietary name]) reduces neuronal excitability by enhancing potassium channel activity. EZG has been approved as adjunctive treatment for adults with partial-onset seizures. OBJECTIVE The goal of this study was to examine the impact of coadministration of ethanol 1 g/kg on the safety and tolerability of EZG and the consequences of coadministration on pharmacokinetic (PK) and pharmacodynamic (PD) parameters in healthy volunteers. METHODS In a randomized, 4-way crossover, partially double-blind study, volunteers received 4 oral treatments (EZG 200 mg + ethanol placebo [light apple juice]; placebo + ethanol 1 g/kg; EZG 200 mg + ethanol 1 g/kg; or placebo + ethanol placebo) separated by 5 to 21 days. RESULTS PK and PD parameters were evaluated in 17 healthy volunteers (19 to 55 years) who were currently moderate alcohol drinkers. Ethanol coadministration increased EZG AUC(0-∞) and C(max) by 36% and 23%, respectively. EZG had no impact on ethanol PK. Ethanol alone impaired balance, blurred vision, and increased intoxication and dizziness. Objective tests (reaction times, response accuracy, attention, and manual tracking) were also impaired by ethanol. EZG treatment alone had no impact on PD measures other than a variable, transient increase in blurred vision (vision clear-crisp visual analog scale scores). Treatments were generally tolerated, with no serious adverse events or discontinuations owing to adverse events. CONCLUSIONS Ethanol increased EZG exposure, which did not seem to be clinically relevant. Except for an increase in blurred vision, impairment effects observed were related primarily to ethanol and were not exacerbated by the addition of EZG, which was generally tolerated with or without ethanol.
Collapse
|
28
|
Brickel N, Derossett S, Buraglio M, Evans C, Jones S. Investigation of the impact of urine handling procedures on interpretation of urinalysis findings and product safety in subjects treated with ezogabine. Ther Clin Risk Manag 2013; 9:207-13. [PMID: 23671389 PMCID: PMC3650885 DOI: 10.2147/tcrm.s42536] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Background Ezogabine (also known by the international nonproprietary name of retigabine) is an antiepileptic drug codeveloped and comarketed by Valeant Pharmaceuticals North America and GlaxoSmithKline, which reduces neuronal excitability by enhancing the activity of potassium channels and has the potential to have effects on the urinary system through a pharmacologic action on bladder smooth muscle. In a single post-herpetic neuralgia trial, but not in an extensive epilepsy development program, proteinuria was unexpectedly reported in patients receiving ezogabine. Consequently, investigations were conducted to determine whether the reported proteinuria represented a true or false-positive finding. Methods Patients receiving ezogabine 900–1200 mg/day in an open-label extension (Study 303) of a Phase III epilepsy trial voluntarily provided urine samples. Fresh samples were analyzed immediately at the study site, and stabilized aliquots were analyzed 1–3 days after collection at two central laboratories. In an open-label study in healthy volunteers receiving ezogabine 600–900 mg/day (Study RTG114137), urine samples were analyzed fresh (<2 hours after collection) and, using two different stabilizers and storage at room temperature, after 24 and 72 hours. Fluid intake was restricted prior to one sample point. Albumin:creatinine ratios were assessed in both studies. Results In Study 303, there was notable variation in clarity, color, and proteinuria between fresh and stored urine samples, and between samples analyzed at different laboratories. In RTG114137, reporting rates of proteinuria were elevated following storage using one stabilizer, and the frequency of color change from fresh to stored samples differed between the stabilizers and between 24 and 72 hours with one stabilizer. Following fluid restriction, proteinuria rates were elevated with both stabilizers. Poor tolerability of ezogabine 750–900 mg/day resulted in limited titration beyond 750 mg/day and early termination of RTG114137. Conclusion Hydration status, interval between urine collection and analysis, and the type of stabilizer used are all factors that may lead to false-positive proteinuria findings in patients receiving ezogabine and should be borne in mind if abnormalities are reported.
Collapse
Affiliation(s)
- Neil Brickel
- Neurosciences Therapy Area Unit, GlaxoSmithKline, Uxbridge, Middlesex, UK
| | | | | | | | | |
Collapse
|
29
|
Buoen C, Bjerrum OJ, Thomsen MS. How First-Time-in-Human Studies Are Being Performed: A Survey of Phase I Dose-Escalation Trials in Healthy Volunteers Published Between 1995 and 2004. J Clin Pharmacol 2013; 45:1123-36. [PMID: 16172177 DOI: 10.1177/0091270005279943] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
First-time-in-human studies are small, time-lagged dose-escalation studies including volunteer subjects evaluating safety and tolerability. There is little consensus in the design of a first-time-in-human study, and it is difficult to get an overview of studies performed. One hundred five studies comprising 3323 healthy volunteers published in the 5 major clinical pharmacology journals since 1995 were analyzed. The average trial was placebo controlled, double blind including 32 subjects at 5 dose levels but with great variation in cohort size and dose-escalation method. The parallel single-dose design was the most common design, with the crossover designs being more frequent in the early publications. Despite discussions on the optimization of phase I trials, little seems to be happening. The development of study designs and evaluation methods for cancer trials is extensive, but formal statistically based methods and more scientific study designs are unusual in phase I dose-escalation trials in healthy volunteers.
Collapse
Affiliation(s)
- Camilla Buoen
- Department of Pharmacology, Danish University of Pharmaceutical Sciences, Universitetsparken 2, Copenhagen 2100, Denmark
| | | | | |
Collapse
|
30
|
Amabile CM, Vasudevan A. Ezogabine: A Novel Antiepileptic for Adjunctive Treatment of Partial-Onset Seizures. Pharmacotherapy 2013; 33:187-94. [DOI: 10.1002/phar.1185] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
| | - Arvind Vasudevan
- Neurology Hospitalist; Carolinas Medical Center - Northeast; Concord; North Carolina
| |
Collapse
|
31
|
Harris JA, Murphy JA. Retigabine (ezogabine) as add-on therapy for partial-onset seizures: an update for clinicians. Ther Adv Chronic Dis 2012; 2:371-6. [PMID: 23251762 DOI: 10.1177/2040622311421542] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVE The present study reviewed the pharmacology, pharmacokinetics, efficacy, and safety of retigabine (ezogabine), a potential agent for use as adjunctive treatment in refractory partial-onset seizures. METHODS A MEDLINE search (1966-May 2011) was conducted using the key words retigabine, ezogabine, D-23129, epilepsy, and anticonvulsant. Bibliographies of all articles retrieved were also reviewed. All studies including humans and published in English with data describing retigabine for the adjunctive treatment of partial-onset seizures were reviewed. RESULTS Retigabine has been shown to interact with the KCNQ2/KCNQ3 subunits of the potassium channels, GABA(A) receptors, and weakly block sodium and calcium channels. Retigabine is 50-60% bioavailable, metabolized by N-glucuronidation and N-acetylation, 80% protein bound, and has few drug-drug interactions. Recent data suggest that retigabine may have a role as adjunctive treatment for refractory partial-onset seizures. Placebo-controlled trials demonstrated a 23.4-44.3% reduction in seizure frequency with 50% responder rates ranging from 23.2% to 47.0% with varying doses of retigabine. The most common adverse effects, occurring in greater than 10% of subjects in the clinical trials, include abnormal gait, confusion, dizziness, fatigue, headache, nausea, somnolence, speech disorder, tremor, urinary tract infection, and blurred vision. CONCLUSIONS Retigabine is a promising agent for adjunctive treatment of refractory partial-onset seizures.
Collapse
|
32
|
Yamada M, Welty TE. Ezogabine: An Evaluation of Its Efficacy and Safety as Adjunctive Therapy for Partial-Onset Seizures in Adults. Ann Pharmacother 2012; 46:1358-67. [DOI: 10.1345/aph.1r153] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Objective: To evaluate the safety, efficacy, pharmacokinetics, pharmacodynamic properties, and clinical application of ezogabine (retigabine. INN), an antiepileptic drug approved in 2011. Data Sources: Published data from in vitro, animal, and clinical studies were obtained from PubMed and CINAHL searches, from January 1980 to March 31, 2012. Other relevant data regarding the safety and efficacy of ezogabine were obtained from the Food and Drug Administration and the European Medication Agency Web sites. Study Selection and Data Extraction: Selected articles were prospective in vitro, animal, and controlled clinical studies of ezogabine. Non-English-language articles were excluded. Data Synthesis: In vitro and animal studies show that ezogabine activates voltage-gated potassium channels, leading to reduction of seizure frequency by inhibiting hyperexcitability activity in the central nervous system. Additionally, ezogabine enhances γ-aminobutyric acid (GABA) activity and de novo GABA synthesis. Eight clinical studies of ezogabine have been published, 5 being Phase 1 clinical trials in healthy subjects and 3 being Phase 3 clinical trials in patients with pharmacoresistant partial-onset seizures. Phase 3 clinical trials demonstrated the safety and efficacy of ezogabine in patients with partial-onset seizures. Conclusions: Clinical trials have shown that ezogabine is efficacious as an adjunctive agent in patients with pharmacoresistant partial seizures. Careful monitoring of drug interactions and adverse reactions is necessary. While ezogabine is efficacious (or partial seizures, its precise role in the management of patients with epilepsy is yet to be determined.
Collapse
Affiliation(s)
- Mikiko Yamada
- Department of Pharmacy Practice, School of Pharmacy, University of Kansas, Kansas City
| | - Timothy E Welty
- Department of Pharmacy Practice, School of Pharmacy, University of Kansas
| |
Collapse
|
33
|
Ezogabine (Retigabine) and Its Role in the Treatment of Partial-Onset Seizures: A Review. Clin Ther 2012; 34:1845-56.e1. [DOI: 10.1016/j.clinthera.2012.07.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 07/10/2012] [Accepted: 07/20/2012] [Indexed: 11/21/2022]
|
34
|
Wang X, Zhou H, Zheng J, Huang C, Liu W, Yu L, Zeng S. Identification and characterization of four process-related impurities in retigabine. J Pharm Biomed Anal 2012; 71:148-51. [PMID: 22954446 DOI: 10.1016/j.jpba.2012.07.035] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2012] [Revised: 07/06/2012] [Accepted: 07/10/2012] [Indexed: 11/26/2022]
Abstract
HPLC analysis of retigabine, a novel antiepileptic drug revealed four previously unknown impurities. These were identified by liquid chromatography-tandem mass spectrometry using electrospray ionization and quadrupole time-of-flight mass analyzer. Further, the structures of the impurities were confirmed by synthesis followed by characterization by mass spectrometry, nuclear magnetic resonance spectroscopy, infrared spectroscopy, and chromatographic retention time profile analysis. On the basis of these data and knowledge of the synthetic scheme of retigabine, the four impurities were identified as ethyl 2,4-diaminophenylcarbamate (Imp-1), ethyl 2-amino-4-(benzylamino)phenylcarbamate (Imp-2), ethyl 2-acetamido-4-(4-fluorobenzylamino)phenylcarbamate (Imp-3), and ethyl 4-(4-fluorobenzylamino)-2-nitrophenylcarbamate (Imp-4). The possible mechanisms by which these impurities were formed are also discussed.
Collapse
Affiliation(s)
- Xiangjun Wang
- College of Pharmaceutical Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China
| | | | | | | | | | | | | |
Collapse
|
35
|
Ciliberto MA, Weisenberg JL, Wong M. Clinical utility, safety, and tolerability of ezogabine (retigabine) in the treatment of epilepsy. DRUG HEALTHCARE AND PATIENT SAFETY 2012; 4:81-6. [PMID: 22888276 PMCID: PMC3413039 DOI: 10.2147/dhps.s28814] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
One-third of patients with epilepsy continue to have seizures despite current treatments, indicating the need for better antiseizure medications with novel mechanisms of action. Ezogabine (retigabine) has recently been approved for adjunctive treatment of partial-onset seizures in adult patients with epilepsy. Ezogabine utilizes a novel mechanism of action, involving activation of specific potassium channels. The most common side effects of ezogabine are shared by most antiseizure medications and primarily consist of central nervous system (CNS) symptoms, such as somnolence, dizziness, confusion, and fatigue. In addition, a small percentage of patients on ezogabine experience a unique adverse effect affecting the bladder, which results in urinary hesitancy; thus, patients on ezogabine should be monitored carefully for potential urological symptoms. Overall, ezogabine appears to be well tolerated and represents a reasonable new option for treating patients with intractable epilepsy.
Collapse
Affiliation(s)
- Michael A Ciliberto
- Department of Neurology, Washington University School of Medicine, St Louis, MO, USA
| | | | | |
Collapse
|
36
|
Orhan G, Wuttke TV, Nies AT, Schwab M, Lerche H. Retigabine/Ezogabine, a KCNQ/KV7 channel opener: pharmacological and clinical data. Expert Opin Pharmacother 2012; 13:1807-16. [DOI: 10.1517/14656566.2012.706278] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
37
|
Porter RJ, Burdette DE, Gil-Nagel A, Hall ST, White R, Shaikh S, DeRossett SE. Retigabine as adjunctive therapy in adults with partial-onset seizures: integrated analysis of three pivotal controlled trials. Epilepsy Res 2012; 101:103-12. [PMID: 22512894 DOI: 10.1016/j.eplepsyres.2012.03.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Revised: 03/08/2012] [Accepted: 03/09/2012] [Indexed: 11/30/2022]
Abstract
We assessed the efficacy and tolerability of retigabine (RTG; international non-proprietary name)/ezogabine (EZG; US adopted name) as adjunctive therapy in adults with partial-onset seizures in an integrated analysis of three trials. Studies 205, 301 (NCT00232596), and 302 (NCT00235755) were randomized, double-blind, placebo-controlled studies in adults having ≥4 partial-onset seizures per 28 days and receiving 1-3 antiepileptic drugs with/without vagus nerve stimulator. Patients underwent titration to RTG/EZG 600, 900, or 1200 mg/day or to placebo followed by 8 or 12 weeks maintenance. For efficacy analyses, placebo was compared with RTG/EZG 600 and 900 mg/day in Studies 205 and 302, and RTG/EZG 1200 mg/day in Studies 205 and 301. Responder rates (≥50% reduction in baseline seizure frequency) were 35% and 45% for RTG/EZG 600 and 900 mg/day, respectively (placebo=21%; p<0.001), and 50% for RTG/EZG 1200 mg/day (placebo=24%, p<0.001). Reductions in 28-day total partial-seizure frequency (medians: placebo=14%; 600 mg/day=26%, p=0.003; 900 mg/day=37%, p<0.001; placebo=15%; 1200 mg/day=39%, p<0.001) were significantly greater with all RTG/EZG doses vs. placebo from baseline to the double-blind phase, and similarly during the maintenance phase. The most commonly reported (>10%) treatment-emergent adverse events were dizziness, somnolence, headache, and fatigue. RTG/EZG demonstrated efficacy and was generally tolerated as adjunctive therapy in adults with partial-onset seizures in this integrated analysis.
Collapse
Affiliation(s)
- Roger J Porter
- University of Pennsylvania, 461 Timber Lane, Devon, PA 19333, USA.
| | | | | | | | | | | | | |
Collapse
|
38
|
Patsalos PN, Berry DJ. Pharmacotherapy of the third-generation AEDs: lacosamide, retigabine and eslicarbazepine acetate. Expert Opin Pharmacother 2012; 13:699-715. [PMID: 22404663 DOI: 10.1517/14656566.2012.667803] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
INTRODUCTION The search for new, more effective antiepileptic drugs (AEDs) continues. The three most recently approved drugs, the so-called third-generation AEDs, include lacosamide, retigabine and eslicarbazepine acetate and are licensed as adjunctive treatment of partial epilepsy in adults. AREAS COVERED For the above three AEDs, their mechanisms of action, pharmacokinetic characteristics, drug-drug interactions, pharmacotherapeutics, dose and administration and therapeutic drug monitoring are reviewed in this paper. EXPERT OPINION Lacosamide and retigabine act through novel mechanisms, while eslicarbazepine acetate, a pro-drug for eslicarbazepine, acts in a similar manner to several other AEDs. All three AEDs are associated with linear pharmacokinetic and rapid absorption and undergo metabolism. Their drug-drug interaction profile is low (lacosamide and retigabine) to modest (eslicarbazepine) in propensity. At the highest approved doses for the three AEDs, responder rates were similar. The most commonly observed adverse effects compared with placebo were dizziness, headache, diplopia and nausea for lacosamide; dizziness, somnolence and fatigue for retigabine and dizziness and somnolence for eslicarbazepine acetate. The precise role that these new AEDs will have in the treatment of epilepsy and whether they will make a significant impact on the prognosis of intractable epilepsy is not yet known and will have to await further clinical experience.
Collapse
Affiliation(s)
- Philip N Patsalos
- UCL-Institute of Neurology, Department of Clinical and Experimental Epilepsy, Pharmacology and Therapeutics Unit, Queen Square, London, WC1N 3BG, UK.
| | | |
Collapse
|
39
|
Rejdak K, Luszczki JJ, Błaszczyk B, Chwedorowicz R, Czuczwar SJ. Clinical utility of adjunctive retigabine in partial onset seizures in adults. Ther Clin Risk Manag 2012; 8:7-14. [PMID: 22298949 PMCID: PMC3269346 DOI: 10.2147/tcrm.s22605] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
In ~30% of epileptic patients, full seizure control is not possible, which is why the search for novel antiepileptic drugs continues. Retigabine exhibits a mechanism of action that is not shared by the available antiepileptic drugs. This antiepileptic enhances potassium currents via Kv7.2–7.3 channels, which very likely results from destabilization of a closed conformation or stabilization of the open conformation of the channels. Generally, the pharmacokinetics of retigabine are linear and the drug undergoes glucuronidation and acetylation. Results from clinical trials indicate that, in the form of an add-on therapy, retigabine proves an effective drug in refractory epileptic patients. The major adverse effects of the add-on treatment are dizziness, somnolence, and fatigue. This epileptic drug is also considered for other conditions – neuropathic pain, affective disorders, stroke, or even Alzheimer’s disease.
Collapse
Affiliation(s)
- Konrad Rejdak
- Department of Neurology, Medical University of Lublin, Lublin
| | | | | | | | | |
Collapse
|
40
|
Affiliation(s)
- Kyoung Heo
- Department of Neurology, Yonsei University College of Medicine, Seoul, Korea
- Epilepsy Research Institute, Yonsei University College of Medicine, Seoul, Korea
| |
Collapse
|
41
|
Chung SS, Kelly K, Schusse C. New and emerging treatments for epilepsy: review of clinical studies of lacosamide, eslicarbazepine acetate, ezogabine, rufinamide, perampanel, and electrical stimulation therapy. J Epilepsy Res 2011; 1:35-46. [PMID: 24649444 PMCID: PMC3952328 DOI: 10.14581/jer.11008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Accepted: 11/17/2011] [Indexed: 01/26/2023] Open
Abstract
Although many different medical and surgical treatment options for epilepsy exist, approximately 30% of epilepsy patients remain poorly controlled. For those patients who are refractory to medical treatment, epilepsy surgery often provides meaningful improvement. However, when surgical resection of epileptic foci cannot be offered or failed, combined administration of AEDs or the application of novel AEDs is the most appropriate therapeutic options. The most recent AEDs tend to offer new mechanisms of action and more favorable safety profiles than the first generation of AEDs. More recently, alternative options of thalamic or cortical stimulation emerged as potentiall effective treatment for epilepsy. The purpose of this article is to compare and review clinical information for the new and emerging medications such as lacosamide, eslicarbazepine acetate, ezogabine (retigabine), rufinamide, perampanel, as well as deep brain stimulation and responsive neurostimulation devices.
Collapse
Affiliation(s)
- Steve S. Chung
- Department of Neurology, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, AZ, USA
| | - Kristen Kelly
- Department of Neurology, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, AZ, USA
| | - Courtney Schusse
- Department of Neurology, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, AZ, USA
| |
Collapse
|
42
|
|
43
|
Abstract
Retigabine (ezogabine in the US) opens neuronal voltage-gated potassium channels, resulting in resting membrane potential stabilization, neuronal subthreshold excitability control and anticonvulsant effects. The clinical efficacy of adjunctive oral retigabine in adults with inadequately controlled, partial-onset seizures was demonstrated in two large, well designed, phase III trials (RESTORE-1 and RESTORE-2), generally confirming the findings of an earlier phase IIb study. In the RESTORE trials, retigabine 600, 900 or 1200 mg/day was associated with significantly higher rates of response (i.e. reduction in 28-day total partial seizure frequency of ≥50%) than placebo during both the 12-week maintenance period and the entire 16- or 18-week double-blind phase (i.e. titration plus maintenance) of the studies. Retigabine recipients also had significantly greater median reductions from baseline in 28-day total partial seizure frequency than placebo recipients during these treatment periods. These benefits of retigabine were generally seen irrespective of age, gender, race and baseline seizure frequency, and were maintained for up to 12 months according to interim data from subsequent open-label extension studies, with some patients also experiencing seizure-free periods of up to 12 months. Retigabine was generally well tolerated in adults with partial-onset seizures in the RESTORE studies, with most adverse events being of mild or moderate severity.
Collapse
Affiliation(s)
- Emma D Deeks
- Adis, a Wolters Kluwer Business, Auckland, New Zealand
| |
Collapse
|
44
|
Abstract
Ezogabine is a new drug for adjunctive therapy of partial-onset seizures with a novel mechanism of action. As a potassium-channel facilitator, it promotes membrane repolarization and thus opposes rapid repetitive discharges. Side effects are typical for antiepileptic drugs and the safety profile is good. Occasional instances of urinary difficulty may require surveillance.
Collapse
|
45
|
Abstract
This article discusses seven newly available antiepileptic drugs (AEDs) and agents in phase III development. Lacosamide, licensed as an adjunctive treatment for partial-onset seizures, primarily acts by enhancing sodium channel slow inactivation. At daily doses of 200-600 mg, the drug significantly reduced partial-onset seizures in adults with refractory epilepsy. The most common adverse effects are CNS related. Rufinamide, available as adjunctive treatment for seizures associated with Lennox-Gastaut syndrome, has an unclear mechanism of action, although it does block voltage-dependent sodium channels. Coadministration of valproic acid significantly increases rufinamide circulating concentrations. The drug has been shown to have efficacy for partial-onset, primary generalized tonic-clonic, tonic-atonic, absence and atypical absence seizures. Adverse effects are mainly somnolence, nausea and vomiting. Eslicarbazepine acetate, a carbamazepine analogue, was recently licensed as adjunctive treatment for partial-onset seizures. Eslicarbazepine acetate acts at voltage-gated sodium channels, although the precise mechanism of action is unclear. The drug had efficacy for partial-onset seizures in three randomized, double-blind, placebo-controlled studies, using 400, 800 or 1200 mg/day. Adverse effects include dizziness and somnolence. Retigabine (ezogabine) exerts its anticonvulsant effect through the opening of neuronal voltage-gated potassium channels. Following significant seizure reduction rates at dosages of 600, 900 and 1200 mg/day, license applications have been submitted for its use as adjunctive treatment for patients with partial-onset seizures. Dose-related adverse effects include somnolence, confusion and dizziness. Brivaracetam is the n-propyl analogue of levetiracetam. Mixed results have been obtained in phase III studies in patients with partial-onset seizures, and further trials in children, patients with photosensitive epilepsy and patients with partial-onset seizures are ongoing. Dizziness, headache and somnolence are the most common adverse effects reported. Perampanel was designed as an AMPA-type glutamate receptor antagonist. Following encouraging results from phase II studies in patients with refractory partial-onset seizures, recruitment for phase III trials is almost complete. Ganaxolone is a neurosteroid with potent antiepileptic activity that modulates GABA(A) receptors in the CNS. Ganaxolone has shown promise in a variety of seizure types. Dizziness and somnolence have been reported in some patients. The availability of new AEDs has widened the choices for clinicians treating patients with epilepsy. However, given the minimal improvement in prognosis and disappointing efficacy outcomes in double-blind, placebo-controlled, dose-ranging regulatory trials, it seems unlikely that these novel agents will have a major impact on outcomes for people with epilepsy.
Collapse
Affiliation(s)
- Linda J Stephen
- Epilepsy Unit, Division of Cardiovascular and Medical Sciences, Western Infirmary, Glasgow, Scotland
| | | |
Collapse
|
46
|
Weisenberg JL, Wong M. Profile of ezogabine (retigabine) and its potential as an adjunctive treatment for patients with partial-onset seizures. Neuropsychiatr Dis Treat 2011; 7:409-14. [PMID: 21792307 PMCID: PMC3140293 DOI: 10.2147/ndt.s14208] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Epilepsy is a common disease with significant morbidity and mortality. Approximately one-third of patients with epilepsy are refractory to available seizure medications, emphasizing the need to develop better drugs with novel mechanisms of action. Ezogabine, also known as retigabine, is a new potential adjunctive treatment for adults with intractable partial seizures. Ezogabine has a unique mechanism of action consisting of activating KCNQ2/3 (Kv7) potassium channels. Ezogabine has undergone a number of Phase II and III trials demonstrating efficacy at 600,900 and 1200 mg/day in a dose-dependent fashion. The most common adverse events with ezogabine are central nervous system effects, particularly dizziness and somnolence. Urologic symptoms, particularly urinary retention, represent a rare but unique side effect of ezogabine. Ezogabine is predominantly metabolized via glucuronidation. Its half-life is 8 hours, suggesting a need for three-times-a-day administration. Ezogabine exhibits minimal interactions with other seizure medications, except possibly lamotrigine. Ezogabine has potential for clinical applications in other medical conditions beyond epilepsy, such as neuropathic pain, neuromyotonia, and bipolar disease, but these are based primarily on experimental models.
Collapse
Affiliation(s)
- Judith Lz Weisenberg
- Department of Neurology, Washington University School of Medicine, St Louis, MO, USA
| | | |
Collapse
|
47
|
Barrese V, Miceli F, Soldovieri MV, Ambrosino P, Iannotti FA, Cilio MR, Taglialatela M. Neuronal potassium channel openers in the management of epilepsy: role and potential of retigabine. Clin Pharmacol 2010; 2:225-36. [PMID: 22291509 PMCID: PMC3262367 DOI: 10.2147/cpaa.s15369] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Despite the availability of over 20 antiepileptic drugs, about 30% of epileptic patients do not achieve seizure control. Thus, identification of additional molecules targeting novel molecular mechanisms is a primary effort in today's antiepileptic drug research. This paper reviews the pharmacological development of retigabine, an antiepileptic drug with a novel mechanism of action, namely the activation of voltage-gated potassium channels of the Kv7 subfamily. These channels, which act as widespread regulators of intrinsic neuronal excitability and of neurotransmitter-induced network excitability changes, are currently viewed among the most promising targets for anticonvulsant pharmacotherapy. In particular, the present work reviews the pathophysiological role of Kv7 channels in neuronal function, the molecular mechanisms involved in the Kv7 channel-opening action of retigabine, the activity of retigabine in preclinical in vitro and in vivo studies predictive of anticonvulsant activities, and the clinical status of development for this drug as an add-on treatment for pharmacoresistant epilepsy. Particular efforts are devoted to highlighting the potential advantages and disadvantages of retigabine when compared with currently available compounds, in order to provide a comprehensive assessment of its role in therapy for treatment-resistant epilepsies.
Collapse
Affiliation(s)
- Vincenzo Barrese
- Department of Neuroscience, University of Naples Federico II, Naples
| | | | | | | | | | | | | |
Collapse
|
48
|
Attkins N, Betts A, Hepworth D, Heatherington AC. Pharmacokinetics and elucidation of the rates and routes of N-glucuronidation of PF-592379, an oral dopamine 3 agonist in rat, dog, and human. Xenobiotica 2010; 40:730-42. [DOI: 10.3109/00498254.2010.514961] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
|
49
|
Nasreddine W, Beydoun A, Atweh S, Abou-Khalil B. Emerging drugs for partial onset seizures. Expert Opin Emerg Drugs 2010; 15:415-31. [DOI: 10.1517/14728214.2010.492394] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
50
|
Retigabine: the newer potential antiepileptic drug. Pharmacol Rep 2010; 62:211-9. [DOI: 10.1016/s1734-1140(10)70260-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Revised: 10/15/2009] [Indexed: 11/15/2022]
|