ABSTRACT
PURPOSE: Prenatal exposure to antiseizure medications (ASMs) has been associated with an increased risk of major malformations and neurodevelopmental disorders, with the latter being mainly associated with valproate (VPA). Our aim was to compare neurocognitive outcome at age 6-7 years in children exposed prenatally to lamotrigine (LTG), carbamazepine (CBZ), valproate (VPA) or levetiracetam (LEV) monotherapy. METHODS: Eligible mother-child pairs were identified from the observational prospective multinational EURAP cohort study. Assessor-blinded testing was conducted at age 6-7 years using WISC-III and NEPSY-II. Verbal IQ (VIQ), performance IQ (PIQ), full scale IQ (FSIQ) and performance in neuropsychological tasks were compared across ASM groups by ANOVA. Scores were adjusted for maternal IQ, paternal education, maternal epilepsy type and child sex. RESULTS: Of 169 children enrolled in the study, 162 (LTG n = 80, CBZ n = 37, VPA n = 27, LEV n = 18) had sufficient data from WISC-III, NEPSY-II or both, and were included in the analyses. Observed (unadjusted) PIQ and FSIQ did not differ across exposure groups, but a difference was identified for VIQ (P<0.05), with children exposed to VPA having lower scores than children exposed to LEV (P<0.05) and children from all groups combined (P<0.01). Adjusted VIQ, PIQ and FSIQ scores did not differ significantly across groups, but VPA-exposed children had borderline significantly lower adjusted VIQ scores than children from all groups combined (P=0.051). VPA-exposed children had lower scores in comprehension of instructions before and after adjustment for confounding variables than children exposed to LTG (P<0.001), LEV (P<0.01) or children from all groups combined (p < 0.001). The VPA-exposed group also had lower scores in immediate and delayed memory for faces compared to children exposed to CBZ (P<0.05 and P<0.001, respectively) and LTG (P<0.05 and P<0.02, respectively), and children from all groups combined (P<0.02 and P<0.001, respectively). LEV-exposed children had lower scores in delayed memory for names than children exposed to LTG (P<0.001), CBZ (P<0.001), VPA (P<0.05) and children from all groups combined (P<0.001). CONCLUSIONS: Consistent with previous reports, our results provide evidence for an adverse effect of prenatal exposure to valproate on verbal development. Our finding of relatively weaker performance of VPA-exposed children compared to other ASM exposures in both comprehension of instructions and face memory also suggest that children of mothers treated with VPA are at increased risk for compromised memory functions or altered processing of socially relevant information.
ABSTRACT
The 17th Eilat Conference on New Antiepileptic Drugs and Devices took place in Madrid, Spain on May 5-8, 2024. As usual, the core part of the conference consisted of presentations on investigational drugs at various stages of development for epilepsy-related indications. Summaries of information on compounds in preclinical or early clinical development are included in an accompanying publication (Part I). In this article, we provide summaries for five compounds in more advanced clinical development, i.e. compounds for which some information on antiseizure activity in individuals with epilepsy is available. These investigational treatments include azetukalner (XEN1101), a potent, KV7.2/7.3-specific potassium channel opener in development for the treatment of focal seizures, generalized tonic-clonic seizures, and major depressive disorder; bexicaserin (LP352), a selective 5-HT2C receptor superagonist in development for the treatment of seizures associated with developmental and epileptic encephalopathies; radiprodil, a selective negative allosteric modulator of NR2B subunit-containing N-methyl-D-aspartate glutamate receptors, in development for the treatment of seizures and behavior manifestations associated with disorders caused by gain-of-function mutations in the GRIN1, -2A, -2B, or -2D genes; soticlestat (TAK-935), a selective inhibitor of cholesterol 24-hydroxylase in development for the treatment of seizures associated with Dravet syndrome and Lennox-Gastaut syndrome; and STK-001, an antisense oligonucleotide designed to upregulate Nav1.1 protein expression and improve outcomes in individuals with Dravet syndrome. The diversity in mechanisms of action of these agents illustrates different approaches being pursued in the discovery of novel treatments for seizures and epilepsy. For two of the compounds discussed in this report (azetukalner and soticlestat), clinical evidence of efficacy has already been obtained in a randomized placebo-controlled adjunctive-therapy trial. For the other compounds, adequately powered placebo-controlled efficacy trials have not been completed to date.
ABSTRACT
For >30 years, the Eilat Conference on New Antiepileptic Drugs and Devices has provided a forum for the discussion of advances in the development of new therapies for seizures and epilepsy. The EILAT XVII conference took place in Madrid, Spain, on May 5-8, 2024. Participants included basic scientists and clinical investigators from industry and academia, other health care professionals, and representatives from lay organizations. We summarize in this article information on treatments in preclinical and in early clinical development discussed at the conference. These include AMT-260, a gene therapy designed to downregulate the expression of Glu2K subunits of kainate receptors, in development for the treatment of drug-resistant seizures associated with mesial temporal sclerosis; BHV-7000, a selective activator of heteromeric Kv7.2/7.3 potassium channels, in development for the treatment of focal epilepsy; ETX101, a recombinant adeno-associated virus serotype 9 designed to increase NaV1.1 channel density in inhibitory γ-aminobutyric acidergic (GABAergic) neurons, in development for the treatment of SCN1A-positive Dravet syndrome; GAO-3-02, a compound structurally related to synaptamide, which exerts antiseizure activity at least in part through an action on cannabinoid type 2 receptors; LRP-661, a structural analogue of cannabidiol, in development for the treatment of seizures associated with Lennox-Gastaut syndrome, Dravet syndrome, and tuberous sclerosis complex; OV329, a selective inactivator of GABA aminotransferase, in development for the treatment of drug-resistant seizures; PRAX-628, a functionally selective potent sodium channel modulator with preference for the hyperexcitable state of sodium channels, in development for the treatment of focal seizures; RAP-219, a selective negative allosteric modulator of transmembrane α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor regulatory protein γ-8, in development for the treatment of focal seizures; and rozanolixizumab, a humanized anti-neonatal Fc receptor monoclonal antibody, in development for the treatment of LGI1 autoimmune encephalitis. Treatments in more advanced development are summarized in Part II of this report.
ABSTRACT
At present, there is no internationally accepted set of core outcomes or measurement methods for epilepsy clinical practice. The International Consortium for Health Outcomes Measurement (ICHOM) convened an international working group of experts in epilepsy, people with epilepsy, and their representatives to develop minimum sets of standardized outcomes and outcome measurement methods for clinical practice. Using modified Delphi consensus methods with consecutive rounds of online voting over 12 months, a core set of outcomes and corresponding measurement tool packages to capture the outcomes were identified for infants, children, and adolescents with epilepsy. Consensus methods identified 20 core outcomes. In addition to the outcomes identified for the ICHOM Epilepsy adult standard set, behavioral, motor, and cognitive/language development outcomes were voted as essential for all infants and children with epilepsy. The proposed set of outcomes and measurement methods will facilitate the implementation of the use of patient-centered outcomes in daily practice.
Subject(s)
Consensus , Epilepsy , Outcome Assessment, Health Care , Humans , Epilepsy/diagnosis , Child , Adolescent , Infant , Outcome Assessment, Health Care/standards , Outcome Assessment, Health Care/methods , Delphi Technique , Child, PreschoolABSTRACT
At present, there is no internationally accepted set of core outcomes or measurement methods for epilepsy clinical practice. Therefore, the International Consortium for Health Outcomes Measurement (ICHOM) convened an international working group of experts in epilepsy, people with epilepsy and their representatives to develop minimum sets of standardized outcomes and outcomes measurement methods for clinical practice that support patient-clinician decision-making and quality improvement. Consensus methods identified 20 core outcomes. Measurement tools were recommended based on their evidence of strong clinical measurement properties, feasibility, and cross-cultural applicability. The essential outcomes included many non-seizure outcomes: anxiety, depression, suicidality, memory and attention, sleep quality, functional status, and the social impact of epilepsy. The proposed set will facilitate the implementation of the use of patient-centered outcomes in daily practice, ensuring holistic care. They also encourage harmonization of outcome measurement, and if widely implemented should reduce the heterogeneity of outcome measurement, accelerate comparative research, and facilitate quality improvement efforts.
Subject(s)
Consensus , Epilepsy , Outcome Assessment, Health Care , Humans , Epilepsy/diagnosis , Epilepsy/therapy , Outcome Assessment, Health Care/standards , Outcome Assessment, Health Care/methods , AdultABSTRACT
Safe delivery and optimal peripartum and postpartum care in women with epilepsy (WWE) is a major concern which has received limited attention in recent years. A diagnosis of epilepsy per se is not an indication for a planned cesarean section or induction of labor, even though epidemiological studies indicate that cesarean delivery is more common among WWE compared to the general population. Pregnancy in WWE is associated with an increased risk of obstetrical complications and increased perinatal morbidity and mortality, and these risks may be greater among WWE taking ASMs. Wherever feasible, pregnant WWE should be directed to specialist care. Risk minimization includes, when appropriate, dose adjustment to compensate for pregnancy-related changes in the pharmacokinetics of some ASMs. With respect to postpartum management, WWE should be advised that the benefits of breastfeeding outweigh the small risk of adverse drug reactions in the infant.
Subject(s)
Breast Feeding , Epilepsy , Pregnancy Complications , Humans , Female , Pregnancy , Anticonvulsants/adverse effects , Anticonvulsants/therapeutic use , Delivery, Obstetric , Pregnancy Outcome/epidemiologyABSTRACT
Importance: Women with epilepsy (WWE) require treatment with antiseizure medications (ASMs) during pregnancy, which may be associated with an increased risk of major congenital malformations (MCMs) in their offspring. Objective: To investigate the prevalence of MCMs after prenatal exposure to 8 commonly used ASM monotherapies and changes in MCM prevalence over time. Design, Setting, and Participants: This was a prospective, observational, longitudinal cohort study conducted from June 1999 to October 2022. Since 1999, physicians from more than 40 countries enrolled ASM-treated WWE before pregnancy outcome was known and followed up their offspring until 1 year after birth. Participants aged 14 to 55 years who were exposed to 8 of the most frequently used ASMs during pregnancy were included in this study. Data were analyzed from April to September 2023. Exposure: Maternal use of ASMs at conception. Main Outcomes and Measures: MCMs were assessed 1 year after birth by a committee blinded to type of exposure. Teratogenic outcomes across exposures were compared by random-effects logistic regression adjusting for potential confounders and prognostic factors. Results: A total of 10â¯121 prospective pregnancies exposed to ASM monotherapy met eligibility criteria. Of those, 9840 were exposed to the 8 most frequently used ASMs. The 9840 pregnancies occurred in 8483 women (mean [range] age, 30.1 [14.1-55.2] years). MCMs occurred in 153 of 1549 pregnancies for valproate (9.9%; 95% CI, 8.5%-11.5%), 9 of 142 for phenytoin (6.3%; 95% CI, 3.4%-11.6%), 21 of 338 for phenobarbital (6.2%; 95% CI, 4.1%-9.3%), 121 of 2255 for carbamazepine (5.4%; 95% CI, 4.5%-6.4%), 10 of 204 for topiramate (4.9%; 95% CI, 2.7%-8.8%), 110 of 3584 for lamotrigine (3.1%; 95% CI, 2.5%-3.7%), 13 of 443 for oxcarbazepine (2.9%; 95% CI, 1.7%-5.0%), and 33 of 1325 for levetiracetam (2.5%; 95% CI, 1.8%-3.5%). For valproate, phenobarbital, and carbamazepine, there was a significant increase in the prevalence of MCMs associated with increasing dose of the ASM. Overall prevalence of MCMs decreased from 6.1% (153 of 2505) during the period 1998 to 2004 to 3.7% (76 of 2054) during the period 2015 to 2022. This decrease over time was significant in univariable logistic analysis but not after adjustment for changes in ASM exposure pattern. Conclusions and Relevance: Of all ASMs with meaningful data, the lowest prevalence of MCMs was observed in offspring exposed to levetiracetam, oxcarbazepine, and lamotrigine. Prevalence of MCMs was higher with phenytoin, valproate, carbamazepine, and phenobarbital, and dose dependent for the latter 3 ASMs. The shift in exposure pattern over time with a declining exposure to valproate and carbamazepine and greater use of lamotrigine and levetiracetam was associated with a 39% decline in prevalence of MCMs, a finding that has major public health implications.
Subject(s)
Abnormalities, Drug-Induced , Anticonvulsants , Epilepsy , Pregnancy Complications , Humans , Female , Anticonvulsants/adverse effects , Anticonvulsants/therapeutic use , Adult , Pregnancy , Young Adult , Adolescent , Epilepsy/drug therapy , Epilepsy/epidemiology , Abnormalities, Drug-Induced/epidemiology , Abnormalities, Drug-Induced/etiology , Middle Aged , Longitudinal Studies , Pregnancy Complications/drug therapy , Pregnancy Complications/epidemiology , Prospective Studies , Valproic Acid/adverse effects , Valproic Acid/therapeutic use , Prenatal Exposure Delayed Effects/epidemiology , Prenatal Exposure Delayed Effects/chemically induced , Phenytoin/adverse effects , Phenytoin/therapeutic use , Lamotrigine/adverse effects , Lamotrigine/therapeutic use , Carbamazepine/adverse effects , Phenobarbital/adverse effects , Phenobarbital/therapeutic use , Cohort Studies , Oxcarbazepine/adverse effects , Oxcarbazepine/therapeutic use , PrevalenceABSTRACT
The aim of this study was to investigate the comparative antiseizure activity of the l-enantiomers of d,l-fenfluramine and d,l-norfenfluramine and to evaluate the relationship between their concentration in plasma and brain and anticonvulsant activity. d,l-Fenfluramine, d,l-norfenfluramine and their individual enantiomers were evaluated in the mouse maximal electroshock seizure (MES) test. d,l-Fenfluramine, d,l-norfenfluramine and their individual l-enantiomers were also assessed in the DBA/2 mouse audiogenic seizure model. All compounds were administered intraperitoneally. Brain and plasma concentrations of the test compounds in DBA/2 mice were quantified and correlated with anticonvulsant activity. In the MES test, fenfluramine, norfenfluramine and their enantiomers showed comparable anticonvulsant activity, with ED50 values between 5.1 and 14.8 mg/kg. In the audiogenic seizure model, l-norfenfluramine was 9 times more potent than d,l-fenfluramine and 15 times more potent than l-fenfluramine based on ED50 (1.2 vs. 10.2 and 17.7 mg/kg, respectively). Brain concentrations of all compounds were about 20-fold higher than in plasma. Based on brain EC50 values, l-norfenfluramine was 7 times more potent than d,l-fenfluramine and 13 times more potent than l-fenfluramine (1940 vs. 13,200 and 25,400 ng/g, respectively). EC50 values for metabolically formed d,l-norfenfluramine and l-norfenfluramine were similar to brain EC50 values of the same compounds administered as such, suggesting that, in the audiogenic seizure model, the metabolites were responsible for the antiseizure activity of the parent compounds. Because of the evidence linking d-norfenfluramine to d,l-fenfluramine to cardiovascular and metabolic adverse effects, their l-enantiomers could potentially be safer follow-up compounds to d,l-fenfluramine. We found that, in the models tested, the activity of l-fenfluramine and l-norfenfluramine was comparable to that of the corresponding racemates. Based on the results in DBA/2 mice and other considerations, l-norfenfluramine appears to be a particularly attractive candidate for further evaluation as a novel, enantiomerically pure antiseizure medication.
Subject(s)
Epilepsy, Reflex , Fenfluramine , Mice , Animals , Norfenfluramine/metabolism , Anticonvulsants , Follow-Up Studies , Mice, Inbred DBA , SeizuresABSTRACT
A variety of terms, such as "antiepileptic," "anticonvulsant," and "antiseizure" have been historically applied to medications for the treatment of seizure disorders. Terminology is important because using terms that do not accurately reflect the action of specific treatments may result in a misunderstanding of their effects and inappropriate use. The present International League Against Epilepsy (ILAE) position paper used a Delphi approach to develop recommendations on English-language terminology applicable to pharmacological agents currently approved for treating seizure disorders. There was consensus that these medications should be collectively named "antiseizure medications". This term accurately reflects their primarily symptomatic effect against seizures and reduces the possibility of health care practitioners, patients, or caregivers having undue expectations or an incorrect understanding of the real action of these medications. The term "antiseizure" to describe these agents does not exclude the possibility of beneficial effects on the course of the disease and comorbidities that result from the downstream effects of seizures, whenever these beneficial effects can be explained solely by the suppression of seizure activity. It is acknowledged that other treatments, mostly under development, can exert direct favorable actions on the underlying disease or its progression, by having "antiepileptogenic" or "disease-modifying" effects. A more-refined terminology to describe precisely these actions needs to be developed.
Subject(s)
Epilepsy , Humans , Epilepsy/drug therapy , Epilepsy/etiology , Anticonvulsants/therapeutic use , Behavior Therapy , Consensus , CaregiversABSTRACT
OBJECTIVE: To investigate changes in depressive and suicidality status and their relationship with seizure outcomes after the addition or substitution of another antiseizure medication (ASM) in adults with drug-resistant focal epilepsy. METHODS: Seven hundred seventy consecutively enrolled patients were assessed and followed prospectively for seizure outcome and depressive status over a 6-month period after starting treatment with a newly introduced ASM. The Neurological Disorders Depression Inventory for Epilepsy (NDDIE) was used to screen for depression and suicidality. Correlations of NDDIE results with clinical and treatment-related variables were assessed by using a stepwise logistic regression model. RESULTS: At baseline, 50% of patients had a positive screening test result for depression and 13% had a positive screening test result for suicidal ideation. A psychiatric comorbidity at baseline was associated with a 2.3 times increased risk of an initially negative NDDIE screening result becoming positive at re-assessment after 6 months. In addition, the number of ASMs taken at baseline correlated with an increased risk of a change in depression screening test results from negative to positive during follow-up, whereas no association was identified with sociodemographic and epilepsy-related variables, including seizure outcomes. Approximately 6% of patients who were initially negative at screening for suicidal ideation became positive at the 6-month re-assessment. The risk of switch from a negative to a positive screening test result for suicidal ideation was increased more than two-fold in individuals who screened positive for depression at baseline, and was unrelated to the type of ASM introduced, sociodemographic variables, or seizure outcomes. SIGNIFICANCE: Almost 1 in 5 adults with drug-resistant focal epilepsy who screen negative for depression become positive when re-assessed 6 months after a treatment change. At re-assessment 6 months later, 6.1% who screen initially negative for passive suicidal ideation become positive. These changes in screening status are independent of type of ASM introduced or seizure outcomes but correlate with psychiatric status at baseline.
Subject(s)
Drug Resistant Epilepsy , Epilepsies, Partial , Epilepsy , Suicide , Adult , Humans , Suicidal Ideation , Depression/etiology , Suicide/psychology , Seizures/complications , Epilepsy/complications , Drug Resistant Epilepsy/drug therapy , Drug Resistant Epilepsy/complications , Epilepsies, Partial/drug therapy , Epilepsies, Partial/complicationsABSTRACT
BACKGROUND: Epileptic encephalopathy with spike-wave activation in sleep (EE-SWAS) is a rare syndrome associated with cognitive and behavioural regression. On the basis of mostly small observational and retrospective studies, corticosteroids and clobazam are often considered the most effective treatments for this syndrome. We aimed to compare cognitive outcomes of children with EE-SWAS 6 months after starting treatment with either corticosteroids or clobazam. METHODS: We did a multicentre, randomised controlled trial at eight tertiary referral centres for rare epilepsies in seven European countries. Children were eligible to participate if they were aged 2-12 years, were diagnosed with EE-SWAS within 6 months before inclusion, and had not been treated with corticosteroids or clobazam previously. Participants were randomly assigned (1:1) to treatment with corticosteroids (either continuous treatment with 1-2 mg/kg per day of prednisolone orally or pulse treatment with 20 mg/kg per day of methylprednisolone intravenously for 3 days every 4 weeks) or clobazam (0·5-1·2 mg/kg per day orally). The primary outcome was cognitive functioning after 6 months of treatment, which was assessed by either the intelligence quotient (IQ) responder rate (defined as improvement of ≥11·25 IQ points) or the cognitive sum score responder rate (defined as improvement of ≥0·75 points). Safety was assessed by number of adverse events and serious adverse events. Data were analysed in the intention-to-treat population, which included all children as randomised who had primary outcome data available at 6 months. The trial is registered with the Dutch Trial Register, Toetsingonline, NL43510.041.13, and the ISRCTN registry, ISRCTN42686094. The trial was terminated prematurely because enrolment of the predefined number of 130 participants was deemed not feasible. FINDINGS: Between July 22, 2014, and Sept 3, 2022, 45 children were randomly assigned to either corticosteroids (n=22) or clobazam (n=23); two children assigned clobazam dropped out before 6 months and were excluded from the intention-to-treat analysis. At the 6-month assessment, an improvement of 11·25 IQ points or greater was reported for five (25%) of 20 children assigned corticosteroids versus zero (0%) of 18 assigned clobazam (risk ratio [RR] 10·0, 95% CI 1·2-1310·4; p=0·025). An improvement of 0·75 points or more in the cognitive sum score was recorded for one (5%) of 22 children assigned corticosteroids versus one (5%) of 21 children assigned clobazam (RR 1·0, 95% CI 0·1-11·7, p=0·97). Adverse events occurred in ten (45%) of 22 children who received corticosteroids, most frequently weight gain, and in 11 (52%) of 21 children who received clobazam, most often fatigue and behavioural disturbances. Occurrence of adverse events did not differ between groups (RR 0·8, 95% CI 0·4-1·4; p=0·65). Serious adverse events occurred in one child in the corticosteroid group (hospitalisation due to laryngitis) and in two children in the clobazam group (hospitalisation due to seizure aggravation, and respiratory tract infection). No deaths were reported. INTERPRETATION: The trial was terminated prematurely, and the target sample size was not met, so our findings must be interpreted with caution. Our data indicated an improvement in IQ outcomes with corticosteroids compared with clobazam treatment, but no difference was seen in cognitive sum score. Our findings strengthen those from previous uncontrolled studies that support the early use of corticosteroids for children with EE-SWAS. FUNDING: EpilepsieNL, WKZ fund, European Clinical Research Infrastructure Network, and Ming fund.
Subject(s)
Epilepsy, Generalized , Epilepsy , Child , Humans , Adrenal Cortex Hormones/therapeutic use , Clobazam , Methylprednisolone , Retrospective Studies , Child, PreschoolABSTRACT
The effect of fenfluramine and norfenfluramine enantiomers in rodent seizure models and their correlation with the pharmacokinetics of d- and l-fenfluramine in rats have been reported recently. To complement these findings, we investigated the pharmacokinetics of d- and l- norfenfluramine in rat plasma and brain. Sprague-Dawley rats were injected intraperitoneally with 20 mg/kg and 1 mg/kg l- norfenfluramine. A 1 mg/kg dose of d-norfenfluramine was used because higher doses caused severe toxicity. The concentration of each enantiomer in plasma and brain was determined at different time points by liquid chromatography/mass spectrometry. Pharmacokinetic parameters were compared between norfenfluramine enantiomers, and with those reported previously for fenfluramine enantiomers after a 20 mg/kg, i.p., dose. All enantiomers were absorbed rapidly and eliminated, with half-lives ranging from 0.9 h (l-fenfluramine) to 6.1 h (l- norfenfluramine, 20 mg/kg) in plasma, and from 3.6 h (d-fenfluramine) to 8.0 h (l-fenfluramine) in brain. Brain-to-plasma concentration ratios ranged from 15.4 (d-fenfluramine) to 27.6 (d-norfenfluramine), indicating extensive brain penetration. The fraction of d- and l-fenfluramine metabolized to norfenfluramine was estimated to be close to unity. This work is part of ongoing investigations to determine the potential value of developing enantiomerically pure l-fenfluramine or l-norfenfluramine as follow-up compounds to the marketed racemic fenfluramine.
Subject(s)
Fenfluramine , Norfenfluramine , Rats , Animals , Norfenfluramine/pharmacokinetics , Rats, Sprague-Dawley , Brain , StereoisomerismABSTRACT
The International League Against Epilepsy (ILAE) introduced a classification for seizure types in 2017 and updated the classification for epilepsy syndromes in 2022. These classifications aim to improve communication among healthcare professionals and help patients better describe their condition. So far, regulatory agencies have used different terminology. This paper stresses the crucial need for consistently adopting ILAE terminology in both regulatory processes and clinical practice. It highlights how language plays a significant role in healthcare communication and how standardized terminology can enhance patient comprehension. The ongoing review of guidelines by regulatory bodies offers a timely opportunity. Aligning regulatory terminologies holds the potential to facilitate discussions on future drug development and harmonize practices across diverse regions, ultimately fostering improved care and research outcomes in epilepsy treatment.
Subject(s)
Epilepsy , Epileptic Syndromes , Humans , Caregivers , Epilepsy/diagnosis , Seizures/diagnosis , ForecastingABSTRACT
Importance: Many patients with focal epilepsy experience seizures despite treatment with currently available antiseizure medications (ASMs) and may benefit from novel therapeutics. Objective: To evaluate the efficacy and safety of XEN1101, a novel small-molecule selective Kv7.2/Kv7.3 potassium channel opener, in the treatment of focal-onset seizures (FOSs). Design, Setting, and Participants: This phase 2b, randomized, double-blind, placebo-controlled, parallel-group, dose-ranging adjunctive trial investigated XEN1101 over an 8-week treatment period from January 30, 2019, to September 2, 2021, and included a 6-week safety follow-up. Adults experiencing 4 or more monthly FOSs while receiving stable treatment (1-3 ASMs) were enrolled at 97 sites in North America and Europe. Interventions: Patients were randomized 2:1:1:2 to receive XEN1101, 25, 20, or 10 mg, or placebo with food once daily for 8 weeks. Dosage titration was not used. On completion of the double-blind phase, patients were offered the option of entering an open-label extension (OLE). Patients not participating in the OLE had follow-up safety visits (1 and 6 weeks after the final dose). Main Outcomes and Measures: The primary efficacy end point was the median percent change from baseline in monthly FOS frequency. Treatment-emergent adverse events (TEAEs) were recorded and comprehensive laboratory assessments were made. Modified intention-to-treat analysis was conducted. Results: A total of 325 patients who were randomized and treated were included in the safety analysis; 285 completed the 8-week double-blind phase. In the 325 patients included, mean (SD) age was 40.8 (13.3) years, 168 (51.7%) were female, and 298 (91.7%) identified their race as White. Treatment with XEN1101 was associated with seizure reduction in a robust dose-response manner. The median (IQR) percent reduction from baseline in monthly FOS frequency was 52.8% (P < .001 vs placebo; IQR, -80.4% to -16.9%) for 25 mg, 46.4% (P < .001 vs placebo; IQR, -76.7% to -14.0%) for 20 mg, and 33.2% (P = .04 vs placebo; IQR, -61.8% to 0.0%) for 10 mg, compared with 18.2% (IQR, -37.3% to 7.0%) for placebo. XEN1101 was generally well tolerated and TEAEs were similar to those of commonly prescribed ASMs, and no TEAEs leading to death were reported. Conclusions and Relevance: The efficacy and safety findings of this clinical trial support the further clinical development of XEN1101 for the treatment of FOSs. Trial Registration: ClinicalTrials.gov Identifier: NCT03796962.
Subject(s)
Epilepsies, Partial , Adult , Female , Humans , Male , Anticonvulsants/adverse effects , Double-Blind Method , Drug Therapy, Combination , Epilepsies, Partial/drug therapy , Potassium Channels/therapeutic use , Seizures/drug therapy , Treatment OutcomeABSTRACT
The inhibitory neurotransmitter γ-aminobutyric acid (GABA) plays an important role in the modulation of neuronal excitability, and a disruption of GABAergic transmission contributes to the pathogenesis of some seizure disorders. Although many currently available antiseizure medications do act at least in part by potentiating GABAergic transmission, there is an opportunity for further research aimed at developing more innovative GABA-targeting therapies. The present article summarises available evidence on a number of such treatments in clinical development. These can be broadly divided into three groups. The first group consists of positive allosteric modulators of GABAA receptors and includes Staccato® alprazolam (an already marketed benzodiazepine being repurposed in epilepsy as a potential rescue inhalation treatment for prolonged and repetitive seizures), the α2/3/5 subtype-selective agents darigabat and ENX-101, and the orally active neurosteroids ETX155 and LPCN 2101. A second group comprises two drugs already marketed for non-neurological indications, which could be repurposed as treatments for seizure disorders. These include bumetanide, a diuretic agent that has undergone clinical trials in phenobarbital-resistant neonatal seizures and for which the rationale for further development in this indication is under debate, and ivermectin, an antiparasitic drug currently investigated in a randomised double-blind trial in focal epilepsy. The last group comprises a series of highly innovative therapies, namely GABAergic interneurons (NRTX-001) delivered via stereotactic cerebral implantation as a treatment for mesial temporal lobe epilepsy, an antisense oligonucleotide (STK-001) aimed at upregulating NaV1.1 currents and restoring the function of GABAergic interneurons, currently tested in a trial in patients with Dravet syndrome, and an adenoviral vector-based gene therapy (ETX-101) scheduled for investigation in Dravet syndrome. Another agent, a subcutaneously administered neuroactive peptide (NRP2945) that reportedly upregulates the expression of GABAA receptor α and ß subunits is being investigated, with Lennox-Gastaut syndrome and other epilepsies as proposed indications. The diversity of the current pipeline underscores a strong interest in the GABA system as a target for new treatment development in epilepsy. To date, limited clinical data are available for these investigational treatments and further studies are required to assess their potential value in addressing unmet needs in epilepsy management.
Subject(s)
Epilepsies, Myoclonic , Epilepsies, Partial , Epilepsy , Lennox Gastaut Syndrome , Infant, Newborn , Humans , Epilepsy/drug therapy , gamma-Aminobutyric Acid/therapeutic use , Randomized Controlled Trials as TopicABSTRACT
γ-Aminobutyric acid (GABA) is the most prevalent inhibitory neurotransmitter in the mammalian brain and has been found to play an important role in the pathogenesis or the expression of many neurological diseases, including epilepsy. Although GABA can act on different receptor subtypes, the component of the GABA system that is most critical to modulation of seizure activity is the GABAA-receptor-chloride (Cl-) channel complex, which controls the movement of Cl- ions across the neuronal membrane. In the mature brain, binding of GABA to GABAA receptors evokes a hyperpolarising (anticonvulsant) response, which is mediated by influx of Cl- into the cell driven by its concentration gradient between extracellular and intracellular fluid. However, in the immature brain and under certain pathological conditions, GABA can exert a paradoxical depolarising (proconvulsant) effect as a result of an efflux of chloride from high intracellular to lower extracellular Cl- levels. Extensive preclinical and clinical evidence indicates that alterations in GABAergic inhibition caused by drugs, toxins, gene defects or other disease states (including seizures themselves) play a causative or contributing role in facilitating or maintaning seizure activity. Conversely, enhancement of GABAergic transmission through pharmacological modulation of the GABA system is a major mechanism by which different antiseizure medications exert their therapeutic effect. In this article, we review the pharmacology and function of the GABA system and its perturbation in seizure disorders, and highlight how improved understanding of this system offers opportunities to develop more efficacious and better tolerated antiseizure medications. We also review the available data for the two most recently approved antiseizure medications that act, at least in part, through GABAergic mechanisms, namely cenobamate and ganaxolone. Differences in the mode of drug discovery, pharmacological profile, pharmacokinetic properties, drug-drug interaction potential, and clinical efficacy and tolerability of these agents are discussed.
Subject(s)
Chlorides , Epilepsy , Animals , Humans , Epilepsy/drug therapy , Brain , Anticonvulsants/pharmacology , Anticonvulsants/therapeutic use , Seizures/drug therapy , MammalsABSTRACT
N-of-1 strategies can provide high-quality evidence of treatment efficacy at the individual level and optimize evidence-based selection of off-label treatments for patients with rare diseases. Given their design characteristics, n-of-1 strategies are considered to lay at the intersection between medical research and clinical care. Therefore, whether n-of-1 strategies should be governed by research or care regulations remains a debated issue. Here, we delineate differences between medical research and optimized clinical care, and distinguish the regulations which apply to either. We also set standards for responsible optimized clinical n-of-1 strategies with (off-label) treatments for rare diseases. Implementing clinical n-of-1 strategies as defined here could aid in optimized treatment selection for such diseases.
Subject(s)
Rare Diseases , Humans , Rare Diseases/drug therapy , Patient Selection , Treatment OutcomeABSTRACT
Drug resistance is estimated to affect about a third of individuals with epilepsy, but its prevalence differs in relation to the epilepsy syndrome, the cause of epilepsy, and other factors such as age of seizure onset and presence of associated neurological deficits. Although drug-resistant epilepsy is not synonymous with unresponsiveness to any drug treatment, the probability of achieving seizure freedom on a newly tried medication decreases with increasing number of previously failed treatments. After two appropriately used antiseizure medications have failed to control seizures, individuals should be referred whenever possible to a comprehensive epilepsy centre for diagnostic re-evaluation and targeted management. The feasibility of epilepsy surgery and other treatments, including those targeting the cause of epilepsy, should be considered early after diagnosis. Substantial evidence indicates that a delay in identifying an effective treatment can adversely affect ultimate outcome and carry an increased risk of cognitive disability, other comorbidities, and premature mortality. Research on mechanisms of drug resistance and novel therapeutics is progressing rapidly, and potentially improved treatments, including those targeting disease modification, are on the horizon.
Subject(s)
Drug Resistant Epilepsy , Epilepsy , Humans , Anticonvulsants/therapeutic use , Epilepsy/drug therapy , Epilepsy/diagnosis , Seizures/drug therapy , Treatment Outcome , Drug Resistant Epilepsy/drug therapy , Drug ResistanceABSTRACT
Unlike several epilepsies with onset in pediatric age, adult-onset epilepsies do not typically have a time course that is predictably self-remitting in the large majority of people. Still, about one-half of individuals with adult-onset epilepsy who have been seizure-free for an extended period (two years or longer) on antiseizure medications (ASMs) will remain in remission when their drug therapy is discontinued. Although a number of predictors of outcome have been identified (including specific adult-onset syndromes associated with a low probability of spontaneous remission), in most cases, the only way to establish whether the epilepsy has remitted in a given individual is to gradually withdraw ASMs. ASM withdrawal can be beneficial, particularly when the currently used treatment is not well tolerated, or could lead to adverse outcomes in the future (i.e., teratogenic effects should pregnancy occur in a female of childbearing potential). However, the risks associated with ASM withdrawal are significant. Relapse of seizures can have major adverse psychosocial consequences and also may carry a risk of morbidity and mortality. Most importantly, evidence suggests that in about 20% of individuals whose seizure relapsed following ASM withdrawal, re-institution of pharmacological therapy may not readily restore seizure control. Ultimately, management decisions should prioritize the preference of the well-informed person with epilepsy. Particularly, when adverse drug effects are a concern, options to be discussed should include not only withdrawal or continuation of the current treatment but also dose reduction or substitution with a different ASM.