Prophylactic antiseizure medications for recurrent status epilepticus in nonsyndromic childhood epilepsy.

PURPOSE: The management of status epilepticus (SE) has mainly focused on the termination of ongoing SE episodes. However, long-term therapeutic strategies for the prevention of SE are lacking. This study aimed to investigate the effectiveness of prophylactic antiseizure medications (ASMs) for SEs in nonsyndromic childhood epilepsy. METHODS: This retrospective study was conducted at Jikei University Hospital. Patients <18 years of age, diagnosed with epilepsy, and experiencing three or more SE episodes within 1 year between April 1, 2017, and October 1, 2021, were included. ASMs introduced for seizure types that developed into SE were evaluated. The effectiveness of ASMs was determined by using the "Rule of Three": An ASM was determined effective if patients were free of SE for a duration at least three times that of their longest SE interval in 12 months prior to intervention. RESULTS: The investigation included a total of 32 ASMs administered to 13 patients. The longest interval between SE episodes before ASM administration was 28-257 d. The first SE interval after ASM administration was 12-797 d. Levetiracetam (LEV) and clobazam (CLB) showed effectiveness in 2/10 and 5/6 patients, respectively. Other ASMs were ineffective. The leading etiology of epilepsy was perinatal brain injury, identified in four patients, and CLB was effective in all of them. CONCLUSIONS: The present study suggests that CLB and LEV may prolong the SE interval in some cases of nonsyndromic childhood epilepsy. CLB may be beneficial, particularly in patients with perinatal brain injury.

Seizure control and complications in patients switching from clobazam to clonazepam due to drug shortage.

BACKGROUND: Antiseizure medication (ASM) shortages are a global problem that have a negative impact on outcomes such as seizure control in patients with epilepsy (PWE). In the case of clobazam (CLB) shortage, there is no study regarding the management strategy. This study aims to investigate the alteration in seizure frequency and the occurrence of side effects in PWE undergoing an abrupt switch from clobazam (CLB) to clonazepam (CLZ), during CLB shortage. MATERIAL AND METHODS: A retrospective study was conducted from electronic health records at our neurology outpatient clinic from January to July 2022. Change in seizure frequency and percentage of CLZ-associated side effects were determined as primary and secondary outcomes, respectively. Potential drug-drug interactions (Level C and above) were evaluated by using Lexicomp Drug Interaction Checker. RESULTS: The analysis included a total of 29 adult patients (15F, median age: 29). The switching ratio was 10 mg CLB for every 1 mg CLZ (10:1). Seizure frequency was higher during the CLZ period compared to the CLB period (p < 0.05), but no status epilepticus cases were observed. All patients exhibited potential drug-drug interactions, leading to reduced CLZ levels in 12 cases. A total of 36 CLZ-associated side effects were identified, with fatigue (19.4 %), drowsiness (16.6 %), and somnolence (13.8 %) being the most prevalent. A positive and strong correlation was found between CLZ dose and the number of side effects (r: 0.556; p: 0.002). CONCLUSION: The abrupt switch from CLB to CLZ was observed to increase seizure frequency without leading to status epilepticus in PWE. CLZ-associated side effects were found to be tolerable despite the abrupt switch. Future studies may explore the effect of alternative switching ratios.

Efficacy and tolerance of cannabidiol in the treatment of epilepsy in patients with Rett syndrome.

We aim to assess the efficacy and tolerance of cannabidiol as adjunctive therapy for Rett syndrome (RTT) patients with epilepsy. We conducted a longitudinal observational study through a monocentric cohort of 46 patients with RTT. Patients were recruited from March 2020 to October 2022 and were treated with Epidyolex® (cannabidiol, CBD, 100 mg/mL oral solution). In our cohort, 26 patients had associated epilepsy (26/46 [56%]), and 10/26 (38%) were treated with CBD, in combination with clobazam in 50% of cases. The median dose at their last follow-up was 15 mg/kg/day. The median treatment duration was 13 months (range: 1-32 months). CBD reduced the incidence of seizures in seven out of 10 patients (70%) with one seizure-free patient, two patients with a reduction of seizures of more than 75%, and four patients with a decrease of more than 50%. No aggravation of symptoms or adverse effects were observed. Only one patient experienced a transitory drooling and somnolence episode at the CBD initiation. Half of the patients showed a reduction in agitation and/or anxiety attacks, and an improvement in spasticity was reported in 4/10 (40%) of patients. CBD appears to have potential therapeutic value for the treatment of drug-resistant epilepsy in Rett syndrome. CBD is well tolerated and, when used in combination with clobazam, may increase the effectiveness of clobazam alone.

Pharmacokinetic Variability of Sulthiame: The Impact of Age, Drug-Drug Interactions, and Biochemical Markers of Toxicity in Patients with Epilepsy.

PURPOSE: Sulthiame is an antiseizure medication increasingly used for epilepsy. The aim of this study was to investigate the pharmacokinetic variability of sulthiame in children and adults with epilepsy with respect to age, comedication, dose, serum concentration, and biochemical markers of toxicity in a clinical setting. METHOD: Retrospective quantitative data from the therapeutic drug monitoring (TDM) database at the Section for Clinical Pharmacology, the National Center for Epilepsy, Norway (2015-2021), were used. RESULTS: TDM data from 326 patients (127 female/199 male) were included [mean age, 11.4 (range 2-44) years; mean weight, 41 (range 14-109) kg]. Interindividual pharmacokinetic variability in the concentration/(dose/body weight) (C/(D/kg)) ratio was 16-fold; intraindividual variability was up to 8-fold (coefficient of variation = 10%-78%). Young children (younger than 6 years) had a significantly lower C/(D/kg) ratio than older age groups ( P < 0.05). Various comedications did not significantly affect the C/(D/kg) ratio, possibly owing to the small sample size. However, CYP2C19-mediated inhibition by sulthiame was indicated because patients using clobazam and sulthiame (n = 28) had a 3.5-fold higher N-desmethylclobazam C/(D/kg) ratio than those using neutral comedication (n = 45; P < 0.001). Patients with pH values below the adjusted normal range (7.32-7.42; n = 15) had a 33% higher sulthiame concentration than those with normal pH values (n = 22; P < 0.05). Blood gas measurements, especially pH, may serve as markers of toxicity and can be used in combination with clinical data when toxicity is suspected. CONCLUSIONS: This study revealed the extensive intraindividual and interindividual pharmacokinetic variability of sulthiame, with age as a contributing factor. Sulthiame has clinically relevant interactions with clobazam. The use of TDM and pH as a biochemical marker may contribute to individualized and safe sulthiame treatment.

Final analysis of potential drug-drug interactions between highly purified cannabidiol and anti-seizure medications in an open-label expanded access program.

OBJECTIVE: The aim of this study was to assess potential drug-drug interactions between highly purified cannabidiol (CBD) and anti-seizure medications (ASMs). METHODS: Our group previously reported that in a sample of adults and children receiving CBD in an open-label expanded access program, there were several ASMs noted to increase in serum levels with increasing doses of CBD. We analyzed if an increased number of observations over time resulted in changes in potential interactions and if potential interactions were associated with time since enrollment, demographics, or the overall rating of adverse effects. RESULTS: In 169 participants (80 adults), with increasing weight-based CBD dose, there were associated increases in serum levels of clobazam and N-desmethylclobazam, free valproate, felbamate, and topiramate in the adult and pediatric arms combined, levetiracetam in the pediatric arm only, and permapanel in the adult arm only. There were no associations noted in these level changes with time since enrollment, biological sex, and adverse events profile scores. SIGNIFICANCE: This study confirms some previously identified interactions with CBD and identifies other potential pharmacokinetic interactions; however, the clinical significance of these observations is likely minor, and there is no effect of time on these findings.

Pharmacokinetics of cenobamate as monotherapy compared with adjunctive therapy.

OBJECTIVE: Cenobamate was approved by the US Food and Drug Administration (FDA) based on studies of adjunctive therapy in patients with focal epilepsy. To support the use of cenobamate monotherapy, this pharmacokinetic (PK)-based simulation analysis evaluated the predicted PK exposure of cenobamate when used as monotherapy versus adjunctive therapy. METHODS: A population pharmacokinetic (PopPK) model of cenobamate was developed using pooled human data from eight phase 1 studies in healthy subjects or special populations, and three phase 2 and 3 studies in patients with focal seizures (N = 960). Concomitant antiseizure medications (ASMs) with a statistically significant effect on the apparent systemic clearance (CL/F) of cenobamate in the PopPK model were used to compare simulated patient plasma exposures (area under the plasma concentration vs time curve [AUC]) following monotherapy versus adjunctive therapy. Treatment equivalence between monotherapy and adjunctive therapy was concluded if the 90% confidence interval (CI) of the geometric mean AUC ratio was within 0.8-1.25. RESULTS: In the PopPK model, statistically significant effects on cenobamate CL/F were shown for clobazam (decreased cenobamate CL/F by 19%) and carbamazepine (increased cenobamate CL/F by 15%); these differences were not considered clinically meaningful. Other ASMs (lacosamide, lamotrigine, levetiracetam, oxcarbazepine, topiramate, and valproate) when coadministered with cenobamate did not have significant effects on the disposition (ie, PK or efficacy) of cenobamate. The geometric mean ratio (90% CIs) of cenobamate AUC for adjunctive therapy/monotherapy was 0.87 (0.816-0.925) for adjunctive carbamazepine and 1.24 (1.147-1.339) for adjunctive clobazam. The 90% CI was within the no-effect limits (90% CIs 0.8-1.25) for adjunctive carbamazepine and partially exceeding no-effect limits for adjunctive clobazam. CONCLUSIONS: Based on the results from this PopPK analysis, cenobamate monotherapy can be expected to result in comparable exposures to those that have been demonstrated to be safe and effective when used as adjunctive therapy for the treatment of focal seizures, supporting the use of cenobamate as monotherapy in these patients.

Retrospective chart review study of use of cannabidiol (CBD) independent of concomitant clobazam use in patients with Lennox-Gastaut syndrome or Dravet syndrome.

PURPOSE: This retrospective chart review study (GWEP20052) evaluated plant-derived highly purified cannabidiol (CBD; Epidyolex®; 100 mg/mL oral solution) use without clobazam as add-on therapy in patients aged ≥2 years with Lennox-Gastaut syndrome (LGS) or Dravet syndrome (DS) enrolled in a European Early Access Program. METHODS: Data were extracted from patient charts covering a period starting 3 months before CBD treatment and concluding after 12 months of CBD treatment, or sooner if a patient discontinued CBD or started clobazam. RESULTS: Of 114 enrolled patients, data were available for 107 (92 LGS, 15 DS) who received CBD without clobazam for ≥3 months. Mean age: 14.5 (LGS) and 10.5 (DS) years; female: 44% (LGS) and 67% (DS). Mean time-averaged CBD dose: 13.54 (LGS) and 11.56 (DS) mg/kg/day. Median change from baseline in seizure frequency per 28 days over 3-month intervals varied from -6.2% to -20.9% for LGS and 0% to -16.7% for DS. Achievement of ≥50% reduction in drop (LGS) or convulsive (DS) seizures at 3 and 12 months: LGS, 19% (n = 69) and 30% (n = 53); DS, 21% (n = 14) and 13% (n = 8). Retention on CBD without clobazam (enrolled set): 94%, 80%, 69%, and 63% at 3, 6, 9, and 12 months. Adverse event (AE) incidence was 31%, most commonly somnolence, seizure, diarrhea, and decreased appetite. Two patients discontinued CBD owing to AEs, and four patients with LGS experienced elevated liver enzymes. CONCLUSION: Results support favorable effectiveness and retention of CBD without concomitant clobazam for up to 12 months in clinical practice.

Proposed anti-seizure medication combinations with rufinamide in the treatment of Lennox-Gastaut syndrome: Narrative review and expert opinion.

Lennox-Gastaut syndrome (LGS) is a severe, chronic, complex form of early childhood-onset epilepsy characterized by multiple seizure types, generalized slow (≤2.5 Hz) spike-and-wave activity and other electroencephalography abnormalities, and cognitive impairment. A key treatment goal is early seizure control, and several anti-seizure medications (ASMs) are available. Due to the low success rate in achieving seizure control with monotherapy and an absence of efficacy data supporting any particular combination of ASMs for treating LGS, a rational approach to selection of appropriate polytherapy should be applied to maximize benefit to patients. Such "rational polytherapy" involves consideration of factors including safety (including boxed warnings), potential drug-drug interactions, and complementary mechanisms of action. Based on the authors' clinical experience, rufinamide offers a well-considered first adjunctive therapy for LGS, particularly in combination with clobazam and other newer agents for LGS, and may be particularly useful for reducing the frequency of tonic-atonic seizures associated with LGS.

Decreased serum concentrations of antiseizure medications in children with drug resistant epilepsy following treatment with ketogenic diet.

OBJECTIVE: To examine the potential influence of a ketogenic diet on serum concentrations of antiseizure medications (ASMs) in children with drug resistant epilepsy. METHODS: We investigated the serum concentrations of ASMs in 25 children with drug resistant epilepsy, 2-13 years of age, treated with a classical ketogenic diet for 12 weeks. The patients were recruited from the National Centre for Epilepsy from August 15th, 2017, to January 24th, 2022. Changes in ASM serum concentrations were analyzed using a mixed effect model analysis. Significance level was set at P < 0.05 for all comparisons. RESULTS: The participants used 12 different ASMs during the study. The mean number of ASMs was 2.4 (±SD 0.7). None of the participants changed the type or dose of the ASMs during the intervention period. The serum concentrations of clobazam (n = 9, P = 0.002), desmethylclobazam (n = 9, P = 0.010), and lamotrigine (n = 6, P = 0.016) decreased significantly during the dietary treatment. The analytes with the largest reduction in serum concentration after 12 weeks of dietary treatment were clobazam (mean change -38%) and desmethylclobazam (mean change -37%). We found no significant change in the serum concentrations of levetiracetam, topiramate, and valproic acid. SIGNIFICANCE: We identified a significant decrease in the serum concentrations of clobazam, desmethylclobazam, and lamotrigine following a 12-week ketogenic diet intervention in children with drug resistant epilepsy. An unintended decrease in the serum concentrations of ASMs may render the patient prone to seizures. Measurements of ASM serum concentrations might be useful in patients on a ketogenic diet, especially in patients with lack of efficacy of the dietary treatment.

Stiripentol for the treatment of seizures associated with Dravet syndrome in patients 6 months and older and taking clobazam.

INTRODUCTION: Stiripentol (STP) is a structurally unique molecule with anticonvulsant and neuroprotective properties in animal and human studies. STP enhances gamma-aminobutyric acid (GABA)ergic neurotransmission and inhibits multiple hepatic isoenzymes (i.e. cytochrome P450 system) involved in the metabolism of other antiseizure medications (ASMs) potentiating their anticonvulsant effects and has proven to be a promising therapy in Dravet Syndrome (DS). AREAS COVERED: The authors review randomized clinical trials and observational studies showing STP efficacy, safety, and tolerability when used as adjunctive therapy with VPA and clobazam in patients with DS. Moreover, they include recent evidence of its use in patients<2 years of age. EXPERT OPINION: Evidence on STP demonstrates clinically meaningful efficacy in both short and long term in patients with DS. In addition to reducing convulsive seizure frequency, STP also markedly reduces the number of status epilepticus episodes and associated medical complications which are more common in younger children. STP adverse effects are generally not severe and often resolve following STP dose reduction or adjustments of concomitant ASMs. STP is approved by the FDA for children aged 6 months and older with DS who are also taking clobazam, making it the only DS-specific ASM for children under age 1 year.

Real-world, long-term evaluation of the tolerability and therapy retention of Epidiolex® (cannabidiol) in patients with refractory epilepsy.

OBJECTIVE: Epidiolex® (CBD) is FDA-approved for seizures associated with Lennox-Gastaut syndrome (LGS), Dravet syndrome (DS), and tuberous sclerosis complex (TSC). Phase III studies suggest that certain adverse effects (AEs), possibly linked to pharmacokinetic/pharmacodynamic (PK/PD) interactions may be therapy-limiting. We sought to identify these factors that contribute to treatment success and retention of therapy. METHODS: A single-center, retrospective review of patients with refractory epilepsy taking Epidiolex® was performed. Kaplan-Meier analysis was performed to describe Epidiolex® retention, as a measure of overall effectiveness. RESULTS: One hundred and twelve patients were screened; 4 were excluded due to loss to follow-up or never starting Epidiolex®. Of 108 patients, mean age was 20.3 years (13.1, range 2 to 63), and 52.8% were female. Mean initial and maintenance doses were 5.3 mg/kg/day (1.3) and 15.3 mg/kg/day (5.8), respectively. At the final evaluation, 75% of patients remained on Epidiolex®. The 25th percentile for discontinuation was 19 months. 46.3% of patients experienced at least one treatment-emergent adverse effect (TEAE) with 14.5% d/c Epidiolex® due to treatment emerging adverse effects (TEAE). The most common reasons for discontinuation were lack of efficacy (37%), increased seizure activity (22%), worsened behavior (22%), and sedation (22%). One out of 27 discontinuations was due to liver function test (LFT) elevations (3.7%). At initiation, 47.2% were concurrently taking clobazam, and 39.2% of those patients had an initial clobazam dose decrease. 53% of patients were able to either discontinue or lower the dose of at least one other antiseizure medication. SIGNIFICANCE: Epidiolex® is generally well-tolerated and the majority continued long-term treatment. Patterns of adverse effects were similar to clinical trials, however gastrointestinal complaints, and significant LFT elevations were less common. Our data suggest most patients discontinue within the first several months of treatment and suggest that further studies designed to evaluate early identification and potential mitigation of adverse effects and including drug interactions are warranted.

A real-life pilot study of the clinical application of pharmacogenomics testing on saliva in epilepsy.

Response to antiseizure medications (ASMs) can be influenced by several gene polymorphisms, causing either lower efficacy or higher occurrence of adverse drug reactions (ADRs). We investigated the clinical utility of salivary pharmacogenomic testing on epilepsy patients. A commercialized pharmacogenomic salivary test was performed in a cohort of epileptic patients. Genetic variants on five genes (i.e., CYP1A2, CYP2C9, CYP2C19, EPHX1, and ABCB1) involved in common ASMs metabolism were selected. Twenty-one individuals (median age [Q1 -Q3 ]: 15 [6.5-28] years) were enrolled. Six patients harboring the homozygous *1F allele in CYP1A2 could have reduced chance of response to stiripentol due to fast metabolism. CYP2C9 had reduced activity in 10 patients (alleles *2 and *3), potentially affecting phenytoin (PHT), phenobarbital (PB), primidone, lacosamide (LCM), and valproic acid metabolism. Seven patients, carrying the *2 allele of CYP2C19, had an increased risk of ADRs with clobazam (CLB), PB, PHT, LCM, brivaracetam; while one individual with the *17 allele in heterozygosity reported a CLB fast metabolism. Six patients showed a CC polymorphism of EPHX1 associated with the impaired efficacy of carbamazepine. ABCB1 polymorphisms related to drug-resistance (3435 CC) or drug-sensitive phenotype (CT or TT) were found in 6 out of 7 patients. Pharmacogenomic testing on saliva proved easy and safe in clinical practice to convey information for the management of epileptic patients, especially those resistant to treatment or sensitive to severe ADRs.

Real-world data on cannabidiol treatment of various epilepsy subtypes: A retrospective, multicenter study.

OBJECTIVE: Cannabidiol (CBD) is approved for treatment of Dravet syndrome (DS), Lennox-Gastaut syndrome (LGS), and tuberous sclerosis complex (TSC). Several studies suggest antiseizure effects also beyond these three epilepsy syndromes. METHODS: In a retrospective multicenter study, we analyzed the efficacy and tolerability of CBD in patients with epilepsy at 16 epilepsy centers. RESULTS: The study cohort comprised 311 patients with epilepsy with a median age of 11.3 (0-72) years (235 children and adolescents, 76 adults). Therapy with CBD was off-label in 91.3% of cases due to age, epilepsy subtype, lack of adjunct therapy with clobazam, and/or higher dose applied. CBD titration regimens were slower than recommended, with good tolerability of higher doses particularly in children. Of all patients, 36.9% experienced a reduction in seizure frequency of >50%, independent of their epilepsy subtype or clobazam co-medication. The median observation period was 15.8 months. About one third of all patients discontinued therapy within the observation period due to adverse effects or lack of efficacy. Adverse effects were reported frequently (46.9%). SIGNIFICANCE: Our study highlights that CBD has an antiseizure effect comparable to other antiseizure medications with a positive safety profile independent of the epilepsy subtype. Comedication with clobazam was not associated with a better outcome. Higher doses to achieve seizure frequency reduction were safe, particularly in children. These findings call for further trials for an extended approval of CBD for other epilepsy subtypes and for children <2 years of age.

Pharmacodynamic synergism contributes to the antiseizure action of cannabidiol and clobazam.

The management of refractory epilepsy involves treatment with more than one antiseizure medication (ASM). Combination of ASMs with distinct mechanisms of action are hypothesized to improve overall treatment effectiveness. In clinical trials, concomitant use of cannabidiol (CBD) and clobazam (CLB) was associated with increased seizure reduction and bidirectional elevation in levels of their active metabolites, 7-hydroxy-cannabidiol (7-OH-CBD) and nor-clobazam (n-CLB). Using isobolographic analysis, we investigated whether CBD and CLB interacted pharmacodynamically. In the mouse maximal electroshock seizure (MES) test, brain tissue levels of CBD and CLB corresponding to seizure prevention in 50% of animals (brain Effective Exposure, bEE50) were 7.9 µM and 1.6 µM, respectively. In the 6 Hz psychomotor seizure model, 7-OH-CBD displayed a 5-fold greater potency than CBD (b-EE50, 8.7 µM vs 47.3 µM). Isobolographic analysis performed on combination of CBD/CLB at 1:1, 3:1, and 1:3 ratios based on equi-effective bEE50 values revealed synergism at all doses with combination indices (CI) of 0.43, 0.62 and 0.75 respectively. These outcomes were independent of pharmacokinetic interaction between CBD and CLB. These findings identify pharmacodynamic synergism as an important factor underlying enhanced antiseizure effect during concomitant CBD and CLB use.

Clinical efficacy and safety of cannabidiol for pediatric refractory epilepsy indications: A systematic review and meta-analysis.

Antiseizure medications (ASMs) are the mainstay for the treatment of seizure disorders. However, about one-third of people with epilepsy remain refractory to current ASMs. Cannabidiol (CBD) has recently been approved as ASM for three refractory epilepsy syndrome indications in children and adults. In this study, we evaluated the overall clinical potential of an oral CBD to treat refractory epilepsy in patients with Dravet syndrome (DS), Lennox-Gastaut syndrome (LGS), and tuberous sclerosis complex (TSC) through a systematic review and meta-analysis. A comprehensive search of databases was conducted, including randomized controlled trials (RCTs) assessing the effect of CBD in epilepsy patients. The review was conducted as per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The review focused on RCTs involving patients receiving highly purified oral CBD (Epidiolex, 10 to 50 mg/kg/day) for up to 16 weeks. A subgroup analysis by syndrome and CBD with or without concomitant clobazam was conducted. The key outcomes were reduction in seizure frequency, differences in 50% responder rates, adverse events, and interactions with clobazam as co-therapy. Odds ratio (OR) with 95% confidence interval (CI) were estimated. Of 1183 articles screened, we included 6 RCTs meeting our eligibility criteria. All studies were considered to have a low risk of bias. In the pooled analysis, CBD treatment was found to be more efficacious compared to placebo (OR = 2.45, 95% CI =1.81-3.32, p < 0.01). Subgroup analysis by syndrome demonstrated the odds of ≥50% reduction in seizures with CBD treatment in patients with DS (OR = 2.26, 95% CI:1.38-3.70), LGS (OR = 2.98, 95% CI:1.83-4.85) and TSC (OR = 1.99, 95% CI = 1.06-3.76). Compared with placebo, CBD was associated with increased adverse events (OR = 1.81, 95% CI = 1.33-2.46) such as diarrhea, somnolence, and sedation, and any serious adverse events (OR = 2.86, 95% CI = 1.63-5.05). Other factors, including dosage and clobazam co-therapy, were significantly associated with a greater effect on seizure control and side effects of CBD. In conclusion, the study shows that CBD is highly efficacious both as standalone and adjunct therapy with clobazam for controlling seizures in DS, LGS, and TSC conditions while limiting side effects. Further pharmacodynamic investigation of CBD actions, drug interaction assessments, and therapeutic management guidelines are warranted.

A novel de novo TET3 loss-of-function variant in a Turkish boy presenting with neurodevelopmental delay and electrical status epilepticus during slow-wave sleep.

BACKGROUND: Beck-Fahrner syndrome is caused by homozygous or heterozygous mutations in TET3 on chromosome 2p13. The general characteristics of this syndrome include behavioral abnormalities such as autistic features, attention-deficit hyperactivity disorder, learning disabilities, and epilepsy. CASE PRESENTATION: Six years old male patient was found to have a de novo TET3 loss-of-function variant by whole-exome sequencing (WES) analysis and was diagnosed with electrical status epilepticus during slow-wave sleep (ESES) based on clinical and electroencephalogram (EEG) characteristics. The patient had a neurodevelopmental delay from the age of 3 months and started experiencing generalized tonic-clonic seizures and regression at the age of 5 years. EEG findings were consistent with ESES, and WES analysis revealed a novel heterozygous nonsense NM_001366022.1:c.1594C > T (p.Arg532*) variant in TET3. Valproic acid and immunotherapy were administered for the first 6 months, and clobazam was administered orally in addition to oral valproic acid therapy for the next 6 months. Clinical improvement was noted regardless of EEG improvement for the first 6 months. EEG improvement was achieved with clobazam. No regression was observed following the discontinuation of immunotherapy. CONCLUSION: Decreased TET3 enzyme activity may be one of the new genetic etiologies of ESES.

Breastfeeding while on treatment with antiseizure medications: a systematic review from the ILAE Women Task Force

We carried out a systematic review of published information on transfer of antiseizure medications (ASMs) into breastmilk, ASM serum concentrations in breastfed infants, and the wellbeing of infants breastfed by mothers on ASM treatment. Information was extracted from 85 relevant articles. No data on ASM levels in breastmilk or in breastfed infants was identified for cannabidiol, cenobamate, clobazam, eslicarbazepine-acetate, everolimus, felbamate, fenfluramine, retigabine, rufinamide, stiripentol, tiagabine, and vigabatrin. For ASMs, with available information on levels in breastfed infants, very low concentrations (in the order of 10% or less of maternal serum concentrations) were reported for carbamazepine, gabapentin, levetiracetam, oxcarbazepine, phenytoin, valproate, and clonazepam. Slightly higher levels (up to approximately 30% of maternal serum concentrations) have been observed with lamotrigine and topiramate, and in single case reports for brivaracetam, lacosamide, and perampanel. High infant levels (30% up to 100% of maternal serum concentrations) have been reported with ethosuximide, phenobarbital and zonisamide. Adverse infant effects during breastfeeding by mothers on ASMs appear to be rare regardless of the type of ASM, but systematic study is limited. Prospective long-term follow-up studies of developmental outcomes among children who have been breastfed by mothers taking ASMs are sparse and have mainly involved children whose mothers were taking carbamazepine, lamotrigine, levetiracetam, phenytoin or valproate as monotherapy while breastfeeding. Although these studies have not indicated poorer outcome among breastfed children compared with those who were not breastfed, further data on long-term outcomes are needed to draw firm conclusions. It is concluded that breastfeeding should in general be encouraged in women taking ASMs, given the well-established benefits of breastfeeding with regard to both short- and long-term infant health in the general population. Counselling needs to be individualized including information on the current knowledge regarding the woman's specific ASM treatment.

Evaluating the efficacy of prototype antiseizure drugs using a preclinical pharmacokinetic approach.

OBJECTIVE: Pharmacokinetics (PK) of a drug drive its exposure, efficacy, and tolerability. A thorough preclinical PK assessment of antiseizure medications (ASMs) is therefore essential to evaluate the clinical potential. We tested protection against evoked seizures of prototype ASMs in conjunction with analysis of plasma and brain PK as a proof-of-principle study to enhance our understanding of drug efficacy and duration of action using rodent seizure models. METHODS: In vivo seizure protection assays were performed in adult male CF-1 mice and Sprague Dawley rats. Clobazam (CLB), N-desmethyl CLB (NCLB), carbamazepine (CBZ), CBZ-10,11-epoxide (CBZE), sodium valproate (VPA), and levetiracetam (LEV) concentrations were quantified in plasma and brain using liquid chromatography-tandem mass spectrometry. Mean concentrations of each analyte were calculated and used to determine PK parameters via noncompartmental analysis in Phoenix WinNonLin. RESULTS: NCLB concentrations were approximately 10-fold greater than CLB in mice. The antiseizure profile of CLB was partially sustained by NCLB in mice. CLB concentrations were lower in rats than in mice. CBZE plasma exposures were approximately 70% of CBZ in both mice and rats, likely contributing to the antiseizure effect of CBZ. VPA showed a relatively short half-life in both mice and rats, which correlated with a sharp decline in efficacy. LEV had a prolonged brain and plasma half-life, associated with a prolonged duration of action in mice. SIGNIFICANCE: The study demonstrates the utility of PK analyses for understanding the seizure protection time course in mice and rats. The data indicate that distinct PK profiles of ASMs between mice and rats likely drive differences in drug efficacy between rodent models.

An Italian consensus on the management of Lennox-Gastaut syndrome.

PURPOSE: Although international guidelines exist, the clinical heterogeneity of Lennox-Gastaut syndrome (LGS) and the increasing availability of new and repurposed drugs (e.g., fenfluramine and cannabidiol) requires a practical guide to patient management in the clinical context. We report the results of a consensus survey among 42 Italian experts in the diagnosis and treatment of LGS. METHODS: The consensus procedure followed a modified Delphi approach. Statements were formulated, based on the most recent published evidence and the clinicians' personal experience, then discussed, and agreed upon by the experts through a two-round voting procedure. Approval of a statement was reached with an average score ≥7. RESULTS: Thirteen statements dealing with three main topics (i.e., clinical diagnosis and prognosis, impact on the Quality of Life (QoL), and treatment strategies) were generated. Six statements achieved a level of agreement sufficient for approval on the first voting round. Following the discussion and a few consequent amendments, most of the statements increased their level of agreement and all 13 were approved. CONCLUSIONS: Overall, the statements draw a slightly more benign picture of this rare and severe disease, highlighting the possibility of remission - albeit modest -, an apparent trend towards lower mortality, and the availability of several effective drugs, to which greater accessibility would be hoped for. Valproate remains a major therapeutic option in LGS patients although lamotrigine, rufinamide, topiramate, cannabidiol, and clobazam are popular therapeutic options in Italy, allowing for a tailor-made antiseizure therapy.

The effectiveness and tolerability of clobazam in the pediatric population: Adjunctive therapy and monotherapy in a large-cohort multicenter study.

OBJECTIVE: To evaluate the effectiveness and tolerability of clobazam therapy in the pediatric population in terms of seizure semiology, epileptic syndromes, and etiological subgroups. METHODS: A retrospective cohort study was conducted consisting of 1710 epileptic children from eight centers in seven geographic regions of Turkey. The initial efficacy of clobazam therapy was evaluated after three months of treatment. The long-term effectiveness of the drug, overall seizure outcomes, and overall therapeutic outcomes were evaluated during 12 months of therapy. RESULTS: Analysis of initial efficacy after the first three months of clobazam therapy showed that 320 (18.7 %) patients were seizure-free, 683 (39.9 %) had > 50 % seizure reductions, and 297 (17.4 %) had < 50 % seizure reductions. A positive response (seizure-free and >50 % seizure reduction) was determined for focal-onset (62.3 %) seizures, epileptic spasms (61.5 %), and generalized onset seisures (57.4). The highest positive response rate among the epileptic syndromes was for self-limited epilepsy with centrotemporal spikes (SeLECTS). The highest negative response rate was for developmental and/or epileptic encephalopathies (DEEs). Magnetic resonance imaging (MRI) revealed a structural etiological diagnosis in 25.8 % of the cohort. A higher positive response rate was observed at MRI in patients with sequelae lesions than in those with congenital lesions. The seizure recurrence rate was higher in the patient group with epilepsy with genetic and metabolic causes, in individuals with more than one seizure type, and in those using three or more antiseizure drugs. CONCLUSIONS: This cohort study provides additional evidence that clobazam is an effective and well-tolerable drug with a high seizure-free rate (18.7 %), a significant seizure reduction rate (57.3 %), and with excellent overall therapeutic outcomes with a low seizure relapse rate and considerable reversible benefits in the pediatric population.