Safety and efficacy of adjunctive cenobamate (YKP3089) in patients with uncontrolled focal seizures: a multicentre, double-blind, randomised, placebo-controlled, dose-response trial

Recent Advances in Pharmacologic Treatments of Drug-Resistant Epilepsy: Breakthrough in Sight

Epilepsy affects approximately 1% of the world population. Patients have recurrent seizures, increased physical and psychiatric comorbidities, and higher mortality rate than the general population. Over the last 40 years, research has resulted in 20 new antiseizure medications (ASMs) approved between 1990 and 2018. In spite of this, up to one-third of patients (~ 1 million patients in the USA) have drug-resistant epilepsy (DRE), with little change between 1982 and 2018, a period of intense new ASM development. A minority of patients with DRE may benefit from surgical treatment, but this specialized care remains challenging to scale. Therefore, the greatest hope for breakthroughs for patients with DRE is in pharmacologic therapies. Recently, several advances promise to change the outcomes for patients with DRE. Cenobamate, a drug with dual mechanisms of modulating sodium channel currents and GABA-A receptors, achieves 90-100% seizure reduction in 25-33% of patients with focal DRE, a response not observed with other ASMs. Fenfluramine, a serotonin-acting drug, dramatically reduces the frequency of convulsive seizures in Dravet syndrome, a devastating developmental epileptic encephalopathy with severe DRE. Both drugs reduce mortality. In addition, the possibility of DRE prevention was recently raised in patients with tuberous sclerosis complex, a relatively common genetic form of epilepsy. A paradigm shift is emerging in the treatment of epilepsy. Seizure freedom has become attainable in a significant proportion of patients with focal DRE, and dramatic seizure reduction has been achieved in a developmental encephalopathy. Coupled with a rich pipeline of new compounds under clinical development, the long sought-after breakthrough in the treatment of epilepsy may finally be in sight.

Efficacy of add-on Cenobamate treatment in refractory epilepsy due to Rasmussen's encephalitis

OBJECTIVE

To assess antiseizure effects of cenobamate, a new antiseizure medication with at least two mechanisms of action, in the rare, highly pharmacoresistant and progressive epilepsy syndrome related to Rasmussen's encephalitis.

METHODS

Three patients from the epilepsy centers in Freiburg, Kork, and Valencia are reported with focal epilepsy which had been pharmacoresistant to more than 10 prior treatment regimens. Assessment included at least 1 year of follow-up after cenobamate introduction and included seizure frequency, seizure severity (in particular status epilepticus) and changes in co-medication.

RESULTS

In the three patients, cenobamate add on treatment proved superior to all prior antiseizure and immunomodulatory treatments which had been individually applied. Not only were focal to bilateral tonic-clonic seizure completely controlled, but also focal motor status epilepticus no longer occurred. Co-medication could be reduced in all patients.

SIGNIFICANCE

This case series in a rare and highly pharmacoresistant epilepsy syndrome suggests high efficacy of cenobamate add-on treatment for seizure control. This may be a valuable information in epilepsy related to Rasmussen encephalitis and calls for further elucidation of the mechanism involved in superior seizure control also compared to prior treatments including sodium channel blockers and benzodiazepines.

PLAIN LANGUAGE SUMMARY

Rasmussen's encephalitis is a rare type of epilepsy that gets worse over time and doesn't respond well to most seizure medications. We describe three patients who tried many treatments without much success, but when they added cenobamate to their treatment, it worked better than the other medications. This also let them lower the overall amount of medication they were taking.

Presurgical Use of Cenobamate for Adult and Pediatric Patients Referred for Epilepsy Surgery: Expert Panel Recommendations

Cenobamate has demonstrated efficacy in patients with treatment-resistant epilepsy, including patients who continued to have seizures after epilepsy surgery. This article provides recommendations for cenobamate use in patients referred for epilepsy surgery evaluation. A panel of six senior epileptologists from the United States and Europe with experience in presurgical evaluation of patients with epilepsy and in the use of antiseizure medications (ASMs) was convened to provide consensus recommendations for the use of cenobamate in patients referred for epilepsy surgery evaluation. Many patients referred for surgical evaluation may benefit from ASM optimization; both ASM and surgical treatment should be individualized. Based on previous clinical studies and the authors' clinical experience with cenobamate, a substantial proportion of patients with treatment-resistant epilepsy can become seizure-free with cenobamate. We recommend a cenobamate trial and ASM optimization in parallel with presurgical evaluations. Cenobamate can be started before phase two monitoring, especially in patients who are found to be suboptimal surgery candidates. As neurostimulation therapies are generally palliative, we recommend trying cenobamate before vagus nerve stimulation (VNS), deep brain stimulation, or responsive neurostimulation (RNS). In surgically remediable cases (mesial temporal sclerosis, benign discrete lesion in non-eloquent cortex, cavernous angioma, etc.), cenobamate use should not delay imminent surgery; however, a patient may decide to defer or even cancel surgery should they achieve sustained seizure freedom with cenobamate. This decision should be made on an individual, case-by-case basis based on seizure etiology, patient preferences, potential surgical risks (mortality and morbidity), and likely surgical outcome. The addition of cenobamate after unsuccessful surgery or palliative neuromodulation may also be associated with better outcomes.

Adjunctive cenobamate in people with focal onset seizures: Insights from the Italian Expanded Access Program

OBJECTIVE

This study was undertaken to assess the effectiveness/tolerability of adjunctive cenobamate, variations in the load of concomitant antiseizure medications (ASMs) and predictors of clinical response in people with focal epilepsy.

METHODS

This was a retrospective study at 21 centers participating in the Italian Expanded Access Program. Effectiveness outcomes included retention and responder rates (≥50% and 100% reduction in baseline seizure frequency). Tolerability/safety outcomes included the rate of treatment discontinuation due to adverse events (AEs) and their incidence. Total drug load was quantified as the number of concomitant ASMs and total defined daily dose (DDD). Concomitant ASMs were also classified according to their mechanism of action and pharmacokinetic interactions to perform explorative subgroup analyses.

RESULTS

A total of 236 subjects with a median age of 38 (Q1-Q3 = 27-49) years were included. At 12 months, cenobamate retention rate was 78.8% and responders were 57.5%. The seizure freedom rates during the preceding 3 months were 9.8%, 12.2%, 16.3%, and 14.0% at 3, 6, 9, and 12 months. A higher percentage of responders was observed among subjects treated with clobazam, although the difference was not statistically significant. A total of 223 AEs were recorded in 133 of 236 participants, leading to cenobamate discontinuation in 8.5% cases. At 12 months, a reduction of one or two concomitant ASMs occurred in 42.6% and 4.3% of the subjects. The median total DDD of all concomitant ASMs decreased from 3.34 (Q1-Q3 = 2.50-4.47) at baseline to 2.50 (Q1-Q3 = 1.67-3.50) at 12 months (p < .001, median percentage reduction = 22.2%). The highest rates of cotreatment withdrawal and reductions in the DDD were observed for sodium channel blockers and γ-aminobutyric acidergic modulators (above all for those linked to pharmacokinetic interactions), and perampanel.

SIGNIFICANCE

Adjunctive cenobamate was associated with a reduction in seizure frequency and in the burden of concomitant ASMs in adults with difficult-to-treat focal epilepsy. The type of ASM associated did not influence effectiveness except for a favorable trend with clobazam.

Cenobamate: real-world data from a retrospective multicenter study

BACKGROUND

Clinical trials have shown that cenobamate (CNB) is an efficacious and safe anti-seizure medication (ASM) for drug-resistant focal epilepsy. Here, we analyzed one of the largest real-world cohorts, covering the entire spectrum of epilepsy syndromes, the efficacy and safety of CNB, and resulting changes in concomitant ASMs.

METHODS

We conducted a retrospective observational study investigating CNB usage in two German tertiary referral centers between October 2020 and June 2023 with follow-up data up to 27 months of treatment. Our primary outcome was treatment response. Secondary outcomes comprised drug response after 12 and 18 months, seizure freedom rates, CNB dosage and retention, adverse drug reactions (ADRs), and changes in concomitant ASMs.

RESULTS

116 patients received CNB for at least two weeks. At 6 months, 98 patients were eligible for evaluation. Thereof 50% (49/98) were responders with no relevant change at 12 and 18 months. Seizure freedom was achieved in 18.4% (18/98) at 6 months, 16.7% (11/66), and 3.0% (1/33) at 12 and 18 months. The number of previous ASMs did not affect the seizure response rate. Overall, CNB was well-tolerated, however, in 7.7% (9/116), ADRs led to treatment discontinuation. The most frequent changes of concomitant ASMs included the discontinuation or reduction of sodium channel inhibitors, clobazam reduction, and perampanel discontinuation, while brivaracetam doses were usually left unchanged.

CONCLUSIONS

CNB proved to be a highly effective and generally well-tolerated ASM in patients with severe drug-resistant epilepsy, comprising a broad array of epilepsy syndromes beyond focal epilepsy.

Cenobamate's Efficacy for Seizure Treatment in Tuberous Sclerosis Complex

BACKGROUND

Epilepsy is prevalent, and seizure control is challenging in patients with tuberous sclerosis complex (TSC). Cenobamate (CBM) has proven efficacy in several studies; however, its benefit in the TSC population is not known.

METHODS

We performed a retrospective review of patients with TSC who received adjunctive CBM for seizure treatments. We assessed treatment efficacy by comparing seizure frequencies three months before CBM (baseline) and those at 3-, 6-, 12-, and 18- month follow-ups.

RESULTS

We identified 70 patients with TSC receiving CBM and excluded 16 with insufficient data. Fifty-four patients aged 2 to 39 years, with an average baseline seizure of 66.1 ± 88.9 per month, were analyzed. Treatment retention rates at 3, 6, 12, and 18 months were 94.4%, 79.6%, 66.7%, 44.4%, and responder rates (proportions of patients who remained on treatment and had ≥50% seizure reduction) were 38.1%, 51.7%, 53.1%, and 59.1%, respectively. Seizure-free rates at these respective follow-ups were 7.1%, 13.8%, 6.3%, and 9.1%. For patients experiencing reduced seizures, the mean percentage of change ranged from 61.5% to 74.6%. Side effects were common (64.8%), particularly sedation (42.6%), behavioral disturbance (24.1%), and gastrointestinal disturbance (22.2%).

CONCLUSIONS

Most patients in this study showed seizure reduction; however, the overall responder and seizure-free rates were lower than the literature, likely due to the unique underlying epileptogenesis in TSC and the challenges of tolerating CBM. The lower treatment retention rates signal areas for improvement in concurrent medication adjustment practices.

One-year seizure freedom and quality of life in patients with drug-resistant epilepsy receiving adjunctive vagus nerve stimulation in Japan

OBJECTIVE

Amount of seizure-free days is a critical determinant of quality of life (QoL) in patients with drug-resistant epilepsy (DRE). The fractions of patients experiencing prolonged periods of seizure freedom with adjunctive vagus nerve stimulation (VNS) have yet to be assessed on a large scale.

METHODS

Retrospective analysis of patients in the Japanese VNS prospective observational registry who experienced at least 1 year of seizure freedom from all seizures, focal seizures, or tonic-clonic seizures (TCS), as well as patient-reported change in QoL in these groups.

RESULTS

The study included 362 patients with DRE, 147 were female (40.6%), and the median age at VNS implant was 23.0 years (range: 1.0-73.0). A total of 225 patients reported focal seizures and 184 patients reported TCS. After 36 months of adjunctive VNS, the cumulative proportion of patients experiencing at least 1 year of complete seizure freedom was 11% (38/356) with an average duration of seizure freedom of 19.4 months. In patients with focal seizures, 25% (n = 57/225) experienced at least 1 year of freedom from focal seizures with an average duration of 24.8 months. Higher cumulative rates of freedom from TCS were observed: 55% (n = 101/184) experienced at least 1 year without TCS with an average duration of TCS-free periods of 28.9 months. 82.1% of patients with 12-month complete seizure freedom reported markedly improved or improved QoL compared with 51.9% of patients who were not seizure-free. QoL changes in patients with 12-month seizure freedom from TCS and focal seizures were similar: 61.8% and 63% of respective patients reported either markedly improved or improved QoL at 36 months.

SIGNIFICANCE

Complete seizure freedom is rare in patients treated with VNS; however, this analysis found approximately half of patients who experienced TCS prior to VNS experienced prolonged periods of freedom from TCS with adjunctive VNS.

PLAIN LANGUAGE SUMMARY

We studied patients in Japan with epilepsy that is difficult to treat. To understand if adding vagus nerve stimulation (VNS) helps such patients, we looked at which patients stopped having all seizures or stopped having a specific seizure type (such as tonic-clonic seizures or focal seizures), and how long these periods lasted. With VNS treatment, about 2 out of 4 patients with tonic-clonic seizures and 1 out of 4 patients with focal seizures had more time without these seizure types. Without seizures, patients felt better about their daily lives. Even patients who still had seizures felt better about their daily lives after 3 years of VNS treatment.

TRIAL REGISTRATION

The clinical trial registry number is UMIN000014728.

Cenobamate as an Early Adjunctive Treatment in Drug-Resistant Focal-Onset Seizures: An Observational Cohort Study

BACKGROUND AND OBJECTIVES

Cenobamate (CNB) is a new antiseizure medication (ASM) to treat drug-resistant, focal-onset seizures. Data on its use in early therapy lines are not yet available, and clinicians frequently consider CNB to be a later ASM drug choice. We investigated the efficacy and safety of CNB as an early adjunctive treatment in drug-resistant, focal-onset seizures.

METHODS

The study population were patients with drug-resistant, focal-onset seizures who were initiated with CNB after they did not respond to two or three lifetime ASMs, including all prior and concomitant ASMs. These patients were matched (1:2) by sex, age, and seizure frequency to controls who were initiated with any ASM other than CNB. All participants participated in the Mainz Epilepsy Registry. We evaluated the retention rate after 12 months of CNB and after each new adjunctive ASM in the control group. In addition, seizure freedom and the response rate (reduction of seizure frequency by ≥ 50% from baseline) after 12 months were estimated.

RESULTS

We included 231 patients aged 44.4 ± 15.8 years. Of these, 33.3% (n = 77) were on CNB, 19.0% (n = 44) on valproate (VPA), 17.3% (n = 40) on lacosamide (LCS), 16.4% (n = 38) on levetiracetam (LEV), and 13.9% (n = 32) on topiramate (TPM). The highest retention rate after 12 months since the beginning of the early adjunctive therapy was observed on CNB (92.0%), compared with LCS (80.0%), LEV (73.3%), VPA (68.2%), or TPM (62.5%) (p < 0.05). Seizure freedom and response rate were also the best on CNB (19.5% and 71.4%, respectively) compared with other ASMs (8.3% and 52.5%, respectively; p < 0.05). No significant differences in adverse events between CNB and other ASMs were observed.

CONCLUSIONS

Our study provides evidence that CNB is an effective ASM with a good safety profile in the early therapy lines of drug-resistant, focal-onset seizures. This data should support medical decision making in the management of patients with refractory epilepsy.

CLINICAL TRIAL ID

NCT05267405.

New epilepsy therapies in development

Epilepsy is a common brain disorder, characterized by spontaneous recurrent seizures, with associated neuropsychiatric and cognitive comorbidities and increased mortality. Although people at risk can often be identified, interventions to prevent the development of the disorder are not available. Moreover, in at least 30% of patients, epilepsy cannot be controlled by current antiseizure medications (ASMs). As a result of considerable progress in epilepsy genetics and the development of novel disease models, drug screening technologies and innovative therapeutic modalities over the past 10 years, more than 200 novel epilepsy therapies are currently in the preclinical or clinical pipeline, including many treatments that act by new mechanisms. Assisted by diagnostic and predictive biomarkers, the treatment of epilepsy is undergoing paradigm shifts from symptom-only ASMs to disease prevention, and from broad trial-and-error treatments for seizures in general to mechanism-based treatments for specific epilepsy syndromes. In this Review, we assess recent progress in ASM development and outline future directions for the development of new therapies for the treatment and prevention of epilepsy.

Relative Bioavailability of Cenobamate Administered as a Crushed Tablet, Either Orally or via Nasogastric Tube, versus an Intact Whole Tablet

Cenobamate is approved for the treatment of focal seizures in adults and is currently available as an oral tablet. Alternative methods of drug administration are needed for patients who are unable to swallow whole intact tablets. This phase 1, open-label, randomized, single-dose, three-way crossover (3-period, 3-treatment, 6-sequence) study (NCT05572255), conducted in healthy volunteers, assessed the relative bioavailability of a crushed 200-mg cenobamate tablet administered orally or via nasogastric (NG) tube compared with an intact 200-mg tablet. Each treatment was separated by a 13-day washout period. Plasma samples for cenobamate concentration analysis were collected pre-dose and at multiple time points up to 264 h post-dose. Standard bioequivalence study criteria were applied to the relative bioavailability assessments. All 90% confidence intervals of test-to-reference geometric mean ratios for cenobamate pharmacokinetic parameters (Cmax, AUClast, and AUCinf) were within 85-110% (predefined limit, 80-125%), suggesting no difference in cenobamate exposures following administration of an intact tablet orally or a crushed tablet orally or via NG tube. All treatment-emergent adverse events (TEAEs) were classified as mild and resolved. There were no deaths or other serious AEs (SAEs), and no TEAEs led to discontinuation. Our results indicate that the administration of cenobamate as a crushed tablet taken orally or via an NG tube can provide additional flexibility when patients cannot swallow intact tablets. Based on the results of this study, cenobamate is now approved by FDA to be taken whole or the tablets can be crushed. The crushed tablet can be mixed with water and either administered by mouth as an oral suspension or administered via a nasogastric tube.

The cenobamate KORK study-A prospective monocenter observational study investigating cenobamate as an adjunctive therapy in refractory epilepsy, with comparisons to historical cohorts treated with add-on lacosamide, perampanel, and brivaracetam

OBJECTIVE

In Europe, cenobamate has been approved for use as an adjunctive therapy in adult patients with epilepsy (PWE) with focal-onset seizures (FOS) who have not responded satisfactorily to treatment with at least two antiseizure medications (ASMs). Pivotal trials and real-world observational studies have demonstrated a high efficacy of cenobamate, even in very difficult-to-treat epilepsies. Our aim was to investigate the efficacy of add-on cenobamate in adult PWE who were prospectively monitored. We compared these results with those previously obtained for add-on lacosamide, perampanel, and brivaracetam therapy.

METHODS

Patients were enrolled from the CENKORK study, which is a prospective, non-interventional, open-label, monocenter cohort study of adult PWE experiencing FOS. The titration of cenobamate was performed according to the guidelines outlined in the summary of product characteristics. The primary outcome measure was the retention rate at 6 months and 1 year. In addition, we assessed seizure-free rates, the proportion of patients achieving at least a 50% seizure reduction, adverse events, and the reasons for treatment discontinuation. These outcome measures were compared with historical controls treated with adjunctive lacosamide, perampanel, or brivaracetam at our center.

RESULTS

Between June 2021 and 2022, 172 PWE with ongoing FOS were included. 22 cases were lost to follow-up, leaving 150 cases for the 1-year assessment. The retention rates at 6 months and 1 year were 88.7% and 80%, respectively. Seizure freedom was achieved in 14% of patients at both the 6-month and 1-year marks, while the ≥50% responder rates were 50% and 61%, respectively. The 6-month retention rate was significantly higher in cenobamate than in other ASMs (p < 0.001 for each comparator). Adverse events were significantly more common with perampanel (p < 0.001).

SIGNIFICANCE

Add-on cenobamate proved to be particularly efficacious compared to our experience with other recently introduced ASMs.

PLAIN LANGUAGE SUMMARY

This observational study was carried out in 172 adult patients with difficult-to-treat epilepsy who were treated with adjunctive cenobamate. After 1 year, the data of 150 patients could be analyzed. Seizure freedom, in the preceding 3 months, was achieved in 14%. The rate of PWE continuing cenobamate was 80%. In our hands, cenobamate showed promising efficacy and tolerability even when compared to other recently introduced antiseizure medications.

Efficacy and safety of add-on antiseizure medications for focal epilepsy: A network meta-analysis

OBJECTIVE

Several antiseizure medications (ASMs) have been approved for the treatment of focal epilepsy. However, there is a paucity of evidence on direct comparison of ASMs. We evaluated the comparative efficacy and safety of all approved add-on ASMs for the treatment of focal epilepsy using network meta-analysis.

METHODS

Data through extensive literature search was retrieved from PubMed, Embase, Cochrane, and ClinicalTrial.gov databases using predefined search terms from inception through March 2023. PRISMA reporting guidelines (CRD42023403450) were followed in this study. Efficacy outcomes assessed were ≥50%, ≥75%, and 100% responder rates. Patient retention rate and safety outcomes such as overall treatment-emergent adverse events (TEAEs) and individual TEAEs were assessed. "Gemtc" 4.0.4 package was used to perform Bayesian analysis. Outcomes are reported as relative risks (RRs) and 95% confidence interval (CI).

RESULTS

Literature search retrieved 5807 studies of which, 75 studies were included in the analysis. All ASMs showed significantly higher ≥50% responder rate compared with placebo. Except the ≥75% seizure frequency reduction for zonisamide (2.23; 95% CI: 1.00-5.70) and 100% for rufinamide (2.03; 95% CI: 0.54-11.00), all other interventions showed significantly higher ≥75% and 100% responder rates compared with placebo. Among treatments, significantly higher 100% responder rate was observed with cenobamate compared to eslicarbazepine (10.71; 95% CI: 1.56-323.9) and zonisamide (10.63; 95% CI: 1.37-261.2). All ASMs showed a lower patient retention rate compared to placebo, with the least significant value observed for oxcarbazepine (0.77; 95% CI: 0.7-0.84). Levetiracetam showed a lower risk of incidence (1.0; 95%CI: 0.94-1.1; SUCRA: 0.885067) for overall TEAE compared with other medications.

SIGNIFICANCE

All approved ASMs were effective as add-on treatment for focal epilepsy. Of the ASMs included, cenobamate had the greatest likelihood of allowing patients to attain seizure freedom.

PLAIN LANGUAGE SUMMARY

This article compares the efficacy and safety of antiseizure medications (ASMs) currently available to neurologists in the treatment of epileptic patients. Several newer generation ASMs that have been developed may be as effective or better than the older medications. We included 75 studies in the analysis. In comparison, all drugs improved ≥50%, ≥75% and 100% responder rates compared to control, except for Zonisamide and Rufinamide in the ≥75% and 100% responder rate categories. Retention of patients undergoing treatment was lower in drugs than placebo. All drugs were tolerated, the levetiracetam showed the best tolerability. Cenobamate more likely help completely to reduce seizures.

Cenobamate add-on therapy for drug-resistant focal epilepsy

BACKGROUND

Although most people with epilepsy achieve complete seizure cessation, approximately one-third of those with the condition continue experiencing seizures despite the use of antiseizure medications (ASMs) given as monotherapy or polytherapy. In this review, we summarised the evidence from randomised controlled trials (RCTs) about cenobamate as an add-on treatment for focal epilepsy uncontrolled by one or more concomitant ASMs.

OBJECTIVES

To assess the efficacy and tolerability of add-on oral cenobamate for the treatment of drug-resistant focal-onset seizures, defined as seizures persisting despite treatment with one or more ASMs.

SEARCH METHODS

We searched the Cochrane Register of Studies (CRS Web) and MEDLINE Ovid (September 2022). In addition, we contacted the manufacturer of cenobamate and experts in the field to enquire after any ongoing or unpublished studies.

SELECTION CRITERIA

RCTs comparing add-on cenobamate to placebo or another ASM in people with focal epilepsy uncontrolled by one or more concomitant ASMs.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, extracted data, performed risk of bias assessment, and assessed the certainty of the evidence using the GRADE approach. Our primary outcomes were at least a 50% reduction in total seizure frequency, seizure freedom, and the occurrence of adverse events. We used an intention-to-treat approach for our primary analyses. For each outcome we estimated summary risk ratios (RRs) with their 95% confidence intervals (CIs). We summarised the estimates of effects and certainty of the evidence for each outcome in a summary of findings table.

MAIN RESULTS

We included two studies (659 adult participants, 442 allocated to cenobamate and 217 to placebo). The overall RR for at least a 50% reduction in seizure frequency for add-on cenobamate at any dose compared to placebo was 2.17 (52% versus 24%, 95% CI 1.66 to 2.84; 2 studies, 605 participants; moderate-certainty evidence). The RR for seizure freedom for add-on cenobamate at any dose compared to placebo was 4.45 (16% versus 5%, 95% CI 2.25 to 8.78; 2 studies, 605 participants; moderate-certainty evidence). The RR for the occurrence of adverse events for add-on cenobamate at any dose compared to placebo was 1.14 (77% versus 67%, 95% CI 1.02 to 1.27; 2 studies, 659 participants; moderate-certainty evidence). We judged the two included RCTs as at low or unclear risk of bias. Both studies were sponsored by the drug company that produces cenobamate.

AUTHORS' CONCLUSIONS

Add-on cenobamate is probably better than placebo in reducing the frequency of seizures by at least 50% and in achieving seizure freedom in adults with focal epilepsy uncontrolled by one or more concomitant ASMs (moderate level of certainty). Its use is probably associated with an increased risk of adverse events (moderate level of certainty). Further prospective, controlled trials are required to evaluate the efficacy and tolerability of add-on cenobamate compared to other ASMs. The efficacy and tolerability of cenobamate as adjunctive treatment for focal epilepsy in children should be further investigated. Finally, the long-term efficacy and tolerability of add-on cenobamate treatment in people with other epilepsy types (e.g. generalised epilepsy) or specific epilepsy syndromes, as well as its use as monotherapy, require additional study.

Effectiveness and Safety of Adjunctive Cenobamate in People with Focal-Onset Epilepsy: Evidence from the First Interim Analysis of the BLESS Study

INTRODUCTION

Despite new anti-seizure medications (ASMs) being introduced into clinical practice, about one-third of people with epilepsy do not reach seizure control. Cenobamate is a novel tetrazole-derived carbamate compound with a dual mechanism of action. In randomized controlled trials, adjunctive cenobamate reduced the frequency of focal seizures in people with uncontrolled epilepsy. Studies performed in real-world settings are useful to complement this evidence and better characterize the drug profile.

METHODS

The Italian BLESS ("Cenobamate in Adults With Focal-Onset Seizures") study is an observational cohort study aimed to evaluate the effectiveness, tolerability, and safety of adjunctive cenobamate in adults with uncontrolled focal epilepsy in the context of real-world clinical practice. The study is ongoing and conducted at 50 centers in Italy. This first interim analysis includes participants enrolled until June 2023 and with 12-week outcome data available.

RESULTS

Forty participants with a median age of 36.5 (interquartile range [IQR] 26.0-47.5) years were included. The median monthly seizure frequency at baseline was 6.0 (IQR 2.5-17.3) seizures and 31 (77.5%) participants had failed four or more ASMs before cenobamate. At 12 weeks from starting cenobamate, the median reduction in monthly seizure frequency was 52.8% (IQR 27.1-80.3%); 22 (55.0%) participants had a ≥ 50% reduction in baseline seizure frequency and six (15.0%) reached seizure freedom. The median number of concomitant ASMs decreased from 3 (IQR 2-3) at baseline to 2 (IQR 2-3) at 12 weeks and the proportion of patients treated with > 2 concomitant ASMs decreased from 52.5% to 40.0%. Seven (17.5%) patients reported a total of 12 adverse events, 11 of which were considered adverse drug reactions to cenobamate.

CONCLUSION

In adults with uncontrolled focal seizures, the treatment with adjunctive cenobamate was well tolerated and was associated with improved seizure control and a reduction of the burden of concomitant ASMs.

TRIAL REGISTRATION NUMBER

NCT05859854 (ClinicalTrials.gov Identifier).

Therapeutic strategies during cenobamate treatment initiation: Delphi panel recommendations

The goal of epilepsy treatment is seizure freedom, typically with antiseizure medication (ASM). If patients fail to attain seizure control despite two trials of appropriately chosen ASMs at adequate doses, they are classified as having drug-resistant epilepsy (DRE). Adverse events (AEs) commonly occur in people with DRE because they are typically on ⩾2 ASMs, increasing the potential for drug-drug interactions. Early emerging AEs may impact adherence, decrease quality of life, and delay achieving optimal treatment dosages. Cenobamate is an oral ASM with a long half-life which has proven to be highly effective in clinical trials. An international Delphi panel of expert epileptologists experienced in the clinical use of cenobamate and other ASMs was convened to develop consensus best practices for managing patients during and after cenobamate titration, with consideration for its known pharmacokinetic and pharmacodynamic interactions, to allow patients to reach the most appropriate cenobamate dose while limiting tolerability issues. The modified Delphi process included one open-ended questionnaire and one virtual face-to-face meeting. Participants agreed that cenobamate can be prescribed for most patients experiencing focal-onset seizures. Patients initiating cenobamate therapy should have access to healthcare professionals as needed and their treatment response should be evaluated at the 100-mg dose. Patients with intellectual disabilities may need additional support to navigate the titration period. Proactive down-titration or withdrawal of sodium channel blockers (SCBs) is recommended when concomitant ASM regimens include ⩾2 SCBs. When applicable, maintaining a concomitant clobazam dose at ~5-10 mg may be beneficial. Patients taking oral contraceptives, newer oral anticoagulants, or HIV antiretroviral medications should be monitored for potential interactions. Because clinical evidence informing treatment decisions is limited, guidance regarding dose adjustments of non-ASM drugs was not developed beyond specific recommendations presented in the Summary of Product Characteristics.

Spanish consensus on the management of concomitant antiseizure medications when using cenobamate in adults with drug-resistant focal seizures

OBJECTIVE

Cenobamate is an antiseizure medication (ASM) associated with high rates of seizure freedom and acceptable tolerability in patients with focal seizures. To achieve the optimal cenobamate dose for maximal potential effectiveness while avoiding or minimizing drug-related adverse events (AEs), the administration of cenobamate with other ASMs must be managed through concomitant ASM load reduction. A panel of Spanish epilepsy experts aimed to provide a Spanish consensus on how to adjust the dose of concomitant ASMs in patients with drug-resistant epilepsy (DRE) in order to improve the effectiveness and tolerability of adjunctive cenobamate.

METHODS

A three-stage modified Delphi consensus process was undertaken, including six Spanish epileptologists with extensive experience using cenobamate. Based on current literature and their own expert opinion, the expert panel reached a consensus on when and how to adjust the dosage of concomitant ASMs during cenobamate titration.

RESULTS

The expert panel agreed that tailored titration and close follow-up are required to achieve the best efficacy and tolerability when initiating cenobamate in patients receiving concomitant ASMs. When concomitant clobazam, phenytoin, phenobarbital, and sodium channel blockers are taken at high dosages, or when the patient is receiving two or more sodium channel blockers, dosages should be proactively lowered during the cenobamate titration period. Other concomitant ASMs should be reduced only if the patient reports a moderate/severe AE at any stage of the titration period.

SIGNIFICANCE

Cenobamate is an effective ASM with a dose-dependent effect. To maximize effectiveness while maintaining the best tolerability profile, co-medication management is needed. The recommendations included herein provide practical guidance for proactive and reactive management of co-medication in cenobamate-treated patients with DRE and a high drug load.

PLAIN LANGUAGE SUMMARY

Patients with epilepsy may continue to have seizures even after treatment with several different antiseizure medications (ASMs). Cenobamate is an ASM that can reduce seizures in these patients. In this study, six Spanish experts in epilepsy discussed the best way to use cenobamate in drug-resistant epilepsy. They provide practical guidance on when and how the dose of other ASMs might be adjusted to reduce side effects and optimize the use of cenobamate.

Nonsense mutation in DEPDC5 gene in a patient with carbamazepine-responsive focal epilepsy

•DEPDC-5 is a negative regulator of the mTOR pathway.•DEPDC-5 mutations can cause sleep-related hypermotor epilepsy.•Drug-refractory epilepsy is common in this cohort.•Carbamazepine-responsiveness in DEPDC-5-related epilepsy is described here.

Cenobamate Plasma Levels in Patients with Epilepsy: Correlation with Efficacy and Tolerability?

Objective: Cenobamate is approved by the European Medicine Agency for the treatment of adult patients with epilepsy (PWEs) with ongoing focal-onset seizures despite appropriate treatment with at least two established antiseizure medications. Pivotal trials and post-marketing real-world observational studies suggest high efficacy with unusually high seizure-free rates. The authors sought to investigate the plasma levels of cenobamate under steady-state conditions in seizure-free versus non-responding PWEs, and in PWEs who experienced adverse events versus those who did not. Methods: Blood samples were collected from adult PWEs who were treated with adjunct cenobamate under steady-state conditions. Daily doses, concomitant medications, efficacy, and tolerability were assessed. The plasma cenobamate levels of seizure-free versus non-responding PWEs and between PWEs with and those without clinical adverse events were compared. Results: Samples from 101 PWEs were included. Thirty-six PWEs were seizure-free and 65 were non-responders. In 31 PWEs, adverse events were apparent, whereas in the remaining 70, no tolerability issues were reported. A linear correlation was found between the daily doses (range: 100 mg-400 mg) and the plasma levels (3.8 mg/L-54.6 mg/L). Neither the daily doses nor the plasma levels differed significantly between the investigated subgroups. The main reason for this result was that the individual therapeutic ranges varied widely: seizure freedom and adverse effects were observed alongside low doses and plasma levels in some PWEs. Conversely, there were examples of PWEs who did not respond or who reported no tolerability issues at high doses or plasma levels. Conclusions: To evaluate the individual therapeutic range and to better understand the influence of other drugs in cases where concomitant medications are used, the therapeutic drug monitoring of cenobamate may be useful. A general therapeutic range cannot be defined.

Tetrazole derivatives in the management of neurological disorders: Recent advances on synthesis and pharmacological aspects

Neurological disorders are the leading cause of a large number of mortalities and morbidities. Nitrogen heterocyclic compounds have been pivotal in exhibiting wide array of therapeutic applications. Among them, tetrazole is a ubiquitous class of organic heterocyclic compounds that have attracted much attention because of its unique structural and chemical properties, and a wide range of pharmacological activities comprising anti-convulsant effect, antibiotic, anti-allergic, anti-hypertensive to name a few. Owing to significant chemical and biological properties, the present review aimed at highlighting the recent advances in tetrazole derivatives with special emphasis on their role in the management of neurological diseases. Besides, in-depth structure-activity relationships, molecular docking studies, and associated modes of action of tetrazole derivatives evident in in vitro, in vivo preclinical, and clinical studies have been discussed.

Efficacy and safety of adjunctive cenobamate based on patient etiology: Post-hoc analysis of YKP3089C017 randomized clinical trial

INTRODUCTION

Adjunctive cenobamate was effective and safe for the treatment of uncontrolled focal onset seizures in a randomized, double-blind, placebo-controlled, phase 2 study (YKP3089C017; NCT01866111). This post-hoc analysis assessed the efficacy of adjunctive cenobamate in the treatment of patients with different epileptic etiologies during the study.

METHODS

Adult patients with uncontrolled focal seizures who previously received 1 to 3 antiseizure medications (ASMs) were randomly assigned in a ratio of 1:1:1:1 to receive placebo or cenobamate 100, 200 or 400 mg/day. Patients were further stratified based on their etiologic causes as genetic/presumed genetic, unknown cause, structural cause, and not reported (NR) groups. The frequency per 28 days for an 18-week double-blind treatment period, responder rates (≥50 %, ≥75 %, ≥90 %, and 100 %) during the maintenance phase (12 weeks), and safety were assessed.

RESULTS

A total of 394 patients were categorized into the genetic/presumed genetic (n = 9; 2.28 %), unknown cause (n = 199; 50.51 %), structural cause (n = 177; 44.92 %), and NR (n = 13; 3.30 %) groups, with 4 patients were classified into either of the two etiological causes each. The baseline characteristics were comparable. The percentage of reduction in seizure frequency per 28 days was significantly higher in the cenobamate-treated structural (p = 0.01) and unknown cause (p = 0.0003) groups compared with the placebo group. Responder rates of ≥50 %, ≥75 %, ≥90 %, and 100 % were also higher with cenobamate therapy. Notably, no serious treatment-emergent adverse events (TEAEs) were observed in the genetic/presumed genetic group treated with cenobamate. The most common TEAEs (≥10 %) occurring in patients treated with cenobamate were nervous system disorders by system organ class, and somnolence was the most commonly reported TEAE.

CONCLUSION

Cenobamate reduces seizures in adult patients previously treated with ASMs, with high responder rates and acceptable safety, regardless of underlying causes.

A comparison of cenobamate with other newer antiseizure medications for adjunctive treatment of focal-onset seizures: A systematic review and network meta-analysis

PURPOSE

To compare the efficacy, safety, and tolerability of cenobamate with other newer anti-seizure medications (ASMs) including brivaracetam, eslicarbazepine, lacosamide, perampanel, and zonisamide, approved for adjunctive treatment of drug-resistant focal-onset seizures (FOS) in adults with epilepsy.

METHODS

A systematic literature review (SLR) was conducted to obtain relevant efficacy, safety, and tolerability data for ASMs for the treatment of drug-resistant FOS. All studies were thoroughly assessed for potential sources of heterogeneity and analysed via Bayesian network meta-analyses (NMAs). Efficacy outcomes were ≥50 % responder rate and seizure freedom during the maintenance period, which were modelled simultaneously using a multinomial Bayesian NMA. Safety and tolerability outcomes were the proportion of patients who experienced at least one treatment-emergent adverse event (TEAE) and the proportion who experienced at least one TEAE leading to discontinuation.

RESULTS

The SLR identified 76 studies, of which 23 were included in the Bayesian NMAs. Cenobamate was associated with statistically significant higher rates for the ≥50 % responder rate and seizure freedom outcomes compared with all ASMs analysed. The point estimates indicated that cenobamate was associated with higher rates of experiencing at least one TEAE and at least one TEAE leading to discontinuation compared with brivaracetam, lacosamide, and zonisamide; however, no results were statistically significant.

CONCLUSION

Cenobamate was associated with increased efficacy compared with all ASMs analysed. There were no statistically significant differences in the safety and tolerability outcomes. The results presented corroborate the conclusions drawn from previous published NMAs, which also highlight the notable efficacy of cenobamate in comparison with other ASMs.

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

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.

Inductive reasoning with large language models: a simulated randomized controlled trial for epilepsy

Importance

The analysis of electronic medical records at scale to learn from clinical experience is currently very challenging. The integration of artificial intelligence (AI), specifically foundational large language models (LLMs), into an analysis pipeline may overcome some of the current limitations of modest input sizes, inaccuracies, biases, and incomplete knowledge bases.

Objective

To explore the effectiveness of using an LLM for generating realistic clinical data and other LLMs for summarizing and synthesizing information in a model system, simulating a randomized clinical trial (RCT) in epilepsy to demonstrate the potential of inductive reasoning via medical chart review.

Design

An LLM-generated simulated RCT based on a RCT for treatment with an antiseizure medication, cenobamate, including a placebo arm and a full-strength drug arm, evaluated by an LLM-based pipeline versus a human reader.

Setting

Simulation based on realistic seizure diaries, treatment effects, reported symptoms and clinical notes generated by LLMs with multiple different neurologist writing styles.

Participants

Simulated cohort of 240 patients, divided 1:1 into placebo and drug arms.

Intervention

Utilization of LLMs for the generation of clinical notes and for the synthesis of data from these notes, aiming to evaluate the efficacy and safety of cenobamate in seizure control either with a human evaluator or AI-pipeline.

Measures

The AI and human analysis focused on identifying the number of seizures, symptom reports, and treatment efficacy, with statistical analysis comparing the 50%-responder rate and median percentage change between the placebo and drug arms, as well as side effect rates in each arm.

Results

AI closely mirrored human analysis, demonstrating the drug's efficacy with marginal differences (<3%) in identifying both drug efficacy and reported symptoms.

Conclusions and Relevance

This study showcases the potential of LLMs accurately simulate and analyze clinical trials. Significantly, it highlights the ability of LLMs to reconstruct essential trial elements, identify treatment effects, and recognize reported symptoms, within a realistic clinical framework. The findings underscore the relevance of LLMs in future clinical research, offering a scalable, efficient alternative to traditional data mining methods without the need for specialized medical language training.

Safety and Efficacy of Cenobamate for the Treatment of Focal Seizures in Older Patients: Post Hoc Analysis of a Phase III, Multicenter, Open-Label Study

BACKGROUND

Cenobamate is an antiseizure medication (ASM) approved in the US and Europe for the treatment of uncontrolled focal seizures.

OBJECTIVE

This post hoc analysis of a phase III, open-label safety study assessed the safety and efficacy of adjunctive cenobamate in older adults versus the overall study population.

METHODS

Adults aged 18-70 years with uncontrolled focal seizures taking stable doses of one to three ASMs were enrolled in the phase III, open-label safety study; adults aged 65-70 years from that study were included in our safety analysis. Discontinuations due to adverse events and treatment-emergent adverse events (TEAEs) were assessed throughout the study in all patients who received one or more doses of cenobamate (safety study population). Efficacy was assessed post hoc in patients who had adequate seizure data available (post hoc efficacy population); we assessed patients aged 65-70 years from that population. Overall, 100% responder rates were assessed in the post hoc efficacy maintenance-phase population in 3-month intervals. Concomitant ASM drug load changes were also measured. For each ASM, drug load was defined as the ratio of actual drug dose/day to the World Health Organization defined daily dose (DDD).

RESULTS

Of 1340 patients (mean age 39.7 years) in the safety study population, 42 were ≥ 65 years of age (mean age 67.0 years, 52.4% female). Median duration of exposure was 36.1 and 36.9 months for overall patients and older patients, respectively, and mean epilepsy duration was 22.9 and 38.5 years, respectively. At 1, 2, and 3 years, 80%, 72%, and 68% of patients overall, and 76%, 71%, and 69% of older patients, respectively, remained on cenobamate. Common TEAEs (≥ 20%) were somnolence and dizziness in overall patients, and somnolence, dizziness, fall, fatigue, balance disorder, and upper respiratory tract infection in older patients. Falls in older patients occurred after a mean 452.1 days of adjunctive cenobamate treatment (mean dose 262.5 mg/day; mean concomitant ASM drug load 2.46). Of 240 patients in the post hoc efficacy population, 18 were ≥ 65 years of age. Mean seizure frequency at baseline was 18.1 seizures/28 days for the efficacy population and 3.1 seizures/28 days for older patients. Rates of 100% seizure reduction within 3-month intervals during the maintenance phase increased over time for the overall population (n = 214) and older adults (n = 15), reaching 51.9% and 78.6%, respectively, by 24 months. Mean percentage change in concomitant ASM drug load, not including cenobamate, was reduced in the overall efficacy population (31.8%) and older patients (36.3%) after 24 months of treatment.

CONCLUSIONS

Results from this post hoc analysis showed notable rates of efficacy in older patients taking adjunctive cenobamate. Rates of several individual TEAEs occurred more frequently in older patients. Further reductions in concomitant ASMs may be needed in older patients when starting cenobamate to avoid adverse effects such as somnolence, dizziness, and falls.

CLINICAL TRIALS REGISTRATION

ClinicalTrials.gov NCT02535091.

Current advances in rodent drug-resistant temporal lobe epilepsy models: Hints from laboratory studies

Anti-seizure drugs (ASDs) are the first choice for the treatment of epilepsy, but there is still one-third of patients with epilepsy (PWEs) who are resistant to two or more appropriately chosen ASDs, named drug-resistant epilepsy (DRE). Temporal lobe epilepsy (TLE), a common type of epilepsy usually associated with hippocampal sclerosis (HS), shares the highest proportion of drug resistance (approximately 70%). In view of the key role of the temporal lobe in memory, emotion, and other physiological functions, patients with drug-resistant temporal lobe epilepsy (DR-TLE) are often accompanied by serious complications, and surgical procedures also yield extra considerations. The exact mechanisms for the genesis of DR-TLE remain unillustrated, which makes it hard to manage patients with DR-TLE in clinical practice. Animal models of DR-TLE play an irreplaceable role in both understanding the mechanism and searching for new therapeutic strategies or drugs. In this review article, we systematically summarized different types of current DR-TLE models, and then recent advances in mechanism investigations obtained in these models were presented, especially with the development of advanced experimental techniques and tools. We are deeply encouraged that novel strategies show great therapeutic potential in those DR-TLE models. Based on the big steps reached from the bench, a new light has been shed on the precise management of DR-TLE.

Efficacy and safety of six new antiseizure medications for adjunctive treatment of focal epilepsy and epileptic syndrome: A systematic review and network meta-analysis

OBJECTIVE

This study aimed to evaluate the efficacy and safety of six new antiseizure medications (ASMs) for adjunctive treatment in adult patients with focal epilepsy and adolescents with Dravet syndrome (DS), Lennox-Gastaut syndrome (LGS), or tuberous sclerosis complex (TSC).

METHODS

A comprehensive literature search was performed using PubMed, Medline, Embase, and Cochrane library databases from inception to October 13, 2023. We included published studies for a systematic review and a network meta-analysis (NMA). The efficacy and safety were reported in terms of a 50% response rate and dropout rate along with serious adverse events (SAEs). The outcomes were ranked with the surface under the cumulative ranking curve (SUCRA).

RESULTS

Twenty eligible trials with 5516 patients and 21 interventions, including placebo, contributed to the analysis. Included ASMs were brivaracetam (BRV), cenobamate (CBM), cannabidiol (CBD), fenfluramine (FFM), everolimus (ELM), and soticlestat (SLT). The six new ASMs were compared in four different epilepsy subtypes. In focal epilepsy treatment, BRV seemed to be safe [vs placebo, risk ratio (RR) = 0.69, 95 % confidence interval (CI): 0.25-1.91] and effective (vs placebo, RR = 2.18, 95 % CI: 1.25-3.81). In treating focal epilepsy, CBM 300 mg was more effective at a 50 % response rate (SUCRA 91.8 %) compared with BRV and CBD. However, with the increase in dosage, more SAEs (SUCRA 85.6 %) appeared compared with other ASMs. CBD had good efficacy on LGS (SUCRA 88.4) and DS (SUCRA 66.2), but the effect on adult focal epilepsy was not better than that of placebo [vs placebo, RR = 0.83 (0.36-1.93)]. The NMA indicated that the likelihood of the most appropriate intervention (SUCRA 91.2 %) with minimum side effects（SUCRA 12.5 %）for the DS was FFM. Compared with CBD, high exposure to ELM demonstrated a more effective treatment of TSC (SUCRA 89.7 %). More high-quality SLT studies are needed to further evaluate the efficacy and safety. The comparison-adjusted funnel plots of annualized relapse rate and side effects in the included studies revealed no significant funnel plot asymmetry.

CONCLUSIONS

This NMA indicated that the most effective treatment strategy for focal epilepsy, DS, Lennox-Gastaut syndrome, and TSC, respectively, included CBM 300 mg, FFM, CBD, and ELM. However, the aforementioned findings need further confirmation.

Established and emerging GABAA receptor pharmacotherapy for epilepsy

Drugs that modulate the GABAA receptor are widely used in clinical practice for both the long-term management of epilepsy and emergency seizure control. In addition to older medications that have well-defined roles for the treatment of epilepsy, recent discoveries into the structure and function of the GABAA receptor have led to the development of newer compounds designed to maximise therapeutic benefit whilst minimising adverse effects, and whose position within the epilepsy pharmacologic armamentarium is still emerging. Drugs that modulate the GABAA receptor will remain a cornerstone of epilepsy management for the foreseeable future and, in this article, we provide an overview of the mechanisms and clinical efficacy of both established and emerging pharmacotherapies.

Quantitative Analysis of Cenobamate and Concomitant Anti-Seizure Medications in Human Plasma via Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry

Cenobamate (CNB) is a new anti-seizure medication (ASM) recently introduced in clinical practice after approval by the FDA and EMA for the add-on treatment of focal onset seizures in adult patients. Although its mechanism of action has not been fully understood, CNB showed promising clinical efficacy in patients treated with concomitant ASMs. The accessibility of CNB could pave a way for the treatment of refractory or drug-resistant epilepsies, which still affect at least one-third of the patients under pharmacological treatment. In this context, therapeutic drug monitoring (TDM) offers a massive opportunity for better management of epileptic patients, especially those undergoing combined therapy. Here, we describe the first fully validated ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for the quantification of CNB and concomitant ASMs in human plasma, with samples extracted either manually or by means of a liquid handler. Our method was validated according to the most recent ICH International Guideline M10 for Bioanalytical Method Validation and Study Sample Analysis. The method proved to be selective for CNB and displayed a linear range from 0.8 to 80 mg/L; no matrix effect was found (98.2 ± 4.1%), while intra-day and inter-day accuracy and precision were within the acceptance range. Also, CNB short- and long-term stability in plasma under different conditions was assessed. Leftover human plasma samples were employed as study samples for method validation. Our method proved to be highly sensitive and selective to quantify CNB and concomitant ASMs in human plasma; therefore, this method can be employed for a routinely TDM-based approach to support physicians in the management of an epileptic patient.

Reductions in concomitant antiseizure medication drug load during adjunctive cenobamate therapy: Post-hoc analysis of a subset of patients from a phase 3, multicenter, open-label study

OBJECTIVE

Many patients with epilepsy require polytherapy, which increases their antiseizure medication (ASM) drug load, a measure that considers the doses of all ASMs a patient is taking. Changes in concomitant ASM drug load after adding cenobamate were evaluated post-hoc in a subset of the open-label, phase 3 study.

METHODS

Patients 18-70 years old with uncontrolled focal seizures taking 1-3 ASMs were enrolled. Total concomitant ASM drug load (not including cenobamate) was calculated by dividing the patient's prescribed dose for each ASM by its defined daily dose, per the World Health Organization, then summing the ratios. Changes in concomitant ASM drug load were measured from baseline in 3-month intervals up to 24 months by both total and class-specific ASM drug load. Subgroups of interest included: older adults (65-70 years), prior epilepsy-related surgery vs none, and baseline seizure frequency < 3 vs ≥ 3 seizures/28 days.

RESULTS

Data from 240 patients were available (mean age 41.8 years, mean baseline drug load 3.57). Following cenobamate initiation, the mean concomitant ASM drug load was reduced by 29.4 % at Month 12 % and 31.8 % at Month 24. Reductions occurred in all assessed ASM drug classes, with the largest reduction in benzodiazepines (55.2 % at Month 24). Each assessed subgroup exceeded a 30 % reduction in concomitant ASM drug load at Month 24. Over 24 months, maintenance of ≥ 50 % response occurred in 89.3 %, 86.4 %, and 90.6 % of patients with low (-0.25 to <0), moderate (-0.59 to -0.25), or high (-3.3 to -0.59) numerical reductions in concomitant ASM drug load from baseline, respectively, compared with 86.0 % in patients with no change in drug load; maintenance of 100 % response occurred in 80.7 %, 84.3 %, and 70.0 % of patients with low, moderate, or high numerical reductions in concomitant ASM drug load, compared with 82.0 % in patients with no change.

CONCLUSIONS

Adding cenobamate led to reduced mean concomitant ASM drug loads during 1 and 2 years of treatment. Reductions occurred regardless of ASM drug class, patient age, or epilepsy disease characteristics and did not impact maintenance of response rates.

Cognitive and psychiatric adverse events during adjunctive cenobamate treatment in phase 2 and phase 3 clinical studies

OBJECTIVE

Cognitive and psychiatric adverse events in patients with epilepsy are important determinants of therapeutic outcomes and patient quality of life. We assessed the relationship between adjunctive cenobamate treatment and selected cognitive and psychiatric treatment-emergent adverse events (TEAEs) in adults with uncontrolled focal epilepsy.

METHODS

This was a retrospective analysis of pooled populations of patients with focal epilepsy from two phase 2, randomized, double-blind clinical trials; two open-label extensions (OLEs) of those trials; and a long-term, open-label, phase 3 safety study. Occurrence of cognitive and psychiatric TEAEs in patients treated with adjunctive cenobamate or placebo during double-blind treatment were evaluated. Exposure-adjusted incidence rates of the cognitive and psychiatric TEAEs, defined as the number of TEAEs per patient-year of treatment, during up to 7 years of long-term adjunctive cenobamate treatment, were determined in the pooled OLE and phase 3 patient populations.

RESULTS

The pooled randomized trials resulted in a population of 442 patients treated with cenobamate (100 mg/day: n = 108; 200 mg/day: n = 223; 400 mg/day: n = 111) and 216 placebo-treated patients. The combined open-label studies resulted in pooled populations of cenobamate-treated patients ranging from n = 1690 during Year 1 to n = 103 during Year 7. Among cenobamate-treated (all doses) and placebo-treated patients during double-blind treatment, cognitive TEAEs were reported by ≤ 1.9 % (range, 0 %-1.9 %) and ≤ 0.5 % (range, 0 %-0.5 %), respectively, and psychiatric TEAEs by ≤ 3.6 % (range, 0 %-3.6 %) and ≤ 3.2 % (range, 0 %-3.2 %), respectively. During up to 7 years of open-label adjunctive cenobamate treatment, exposure-adjusted incidence rates of cognitive and psychiatric TEAEs were < 0.018 and < 0.038 events per patient-year, respectively. Discontinuation of adjunctive cenobamate due to cognitive or psychiatric TEAEs assessed in this study during double-blind or open-label treatment occurred in ≤ 0.3 % and ≤ 1.7 % of patients, respectively.

CONCLUSIONS

Cognitive and psychiatric TEAEs were reported by similar numbers of cenobamate- and placebo-treated patients during double-blind adjunctive cenobamate treatment (< 4 % of patients), and exposure-adjusted incidence rates of these TEAEs remained low during open-label cenobamate treatment for up to 7 years. Treatment discontinuations due to these TEAEs were rare. The results of this post-hoc analysis indicate that adjunctive cenobamate treatment exhibits a low incidence of cognitive or psychiatric TEAEs in patients with uncontrolled focal seizures.

Effect of Cenobamate on Cognition in Patients with Drug-Resistant Epilepsy with Focal Onset Seizures: An Exploratory Study

BACKGROUND AND OBJECTIVE

Most second and third generation antiseizure medications (ASMs) are associated with cognitive adverse events, which are a major concern for patients. However, the profile of cognitive adverse events differs between ASMs. This study investigated the effects of cenobamate on cognition in patients with drug-resistant epilepsy (DRE) within the Spanish Expanded Access Program (EAP).

METHODS

This was a retrospective, observational study. Inclusion criteria were age ≥ 18 years, DRE with focal seizures, and availability of cognition assessments and EAP authorization. Data were sourced from the clinical records of patients who took part in the Spanish cenobamate EAP. Primary endpoints included cognition (based on 20 neuropsychological outcomes, including verbal and visuospatial episodic memory, verbal fluency, executive function, working memory, attention, and speed of processing), seizure frequency, and concomitant antiseizure medication (ASM) usage at 6 months.

RESULTS

The study included 20 patients; 10 patients (50%) had daily seizures, 7 (35%) had weekly seizures and 3 (15%) had monthly seizures. The median number of prior antiseizure medications (ASMs) and concomitant ASMs were 10 and 3, respectively. Mean cenobamate doses were 12.5 mg/day at baseline and 191.2 mg/day at 6 months. There was a statistically significant improvement in cognitive scores between baseline and 6 months for two measures of verbal episodic memory (p = 0.0056 and p = 0.0013) and one measure of visuospatial episodic memory (p = 0.011), and a significant worsening in cognitive score for attention (p = 0.030). At 6 months, 14 patients (70%) had a ≥ 50% reduction in seizure frequency, 3 patients (15%) had a ≥ 90% reduction, and 1 patient (5%) was seizure free. There were significant decreases in the mean number of concomitant ASMs (p = 0.0009), the sum of the ratios of prescribing daily dose/daily defined dose (total ratio of DDD) for concomitant ASMs (p < 0.0001), and concomitant ASM drug load (p = 0.038) between baseline and 6 months. Total ratio of DDD was significantly lower at 6 months for perampanel (p = 0.0016), benzodiazepines (p = 0.035), and sodium channel blockers (p = 0.0005) compared with baseline. Based on analysis of covariance, cognitive tests related to verbal or visuospatial episodic memory (e.g., RT of FCSRT, or ROCFT), executive functions (e.g., TMT-B), and processing speed (some 5-Digit Test subtests) appeared to be closely related to the reduction in pharmacological burden rather than the improvement in seizure control.

CONCLUSIONS

Significant improvements in cognition, seizure frequency, and concomitant ASM usage were observed after the introduction of cenobamate in patients with DRE in a real-world setting. Covariance analysis supports the reduction in concomitant ASMs as the most important factor driving cognitive improvements with cenobamate. As this was an exploratory study with an uncontrolled, retrospective design and a low number of patients, further studies are required to confirm the findings.

The efficacy and safety of third-generation antiseizure medications and non-invasive brain stimulation to treat refractory epilepsy: a systematic review and network meta-analysis study

Background

The new antiseizure medications (ASMs) and non-invasive brain stimulation (NIBS) are controversial in controlling seizures. So, this network meta-analysis aimed to evaluate the efficacy and safety of five third-generation ASMs and two NIBS therapies for the treatment of refractory epilepsy.

Methods

We searched PubMed, EMBASE, Cochrane Library and Web of Science databases. Brivaracetam (BRV), cenobamate (CNB), eslicarbazepine acetate (ESL), lacosamide (LCM), perampanel (PER), repetitive transcranial magnetic stimulation (rTMS), and transcranial direct current stimulation (tDCS) were selected as additional treatments for refractory epilepsy in randomized controlled studies and other cohort studies. Randomized, double-blind, placebo-controlled, add-on studies that evaluated the efficacy or safety of medication and non-invasive brain stimulation and included patients with seizures were uncontrolled by one or more concomitant ASMs were identified. A random effects model was used to incorporate possible heterogeneity. The primary outcome was the change in seizure frequency from baseline, and secondary outcomes included the proportion of patients with ≥50% reduction in seizure frequency, and the rate of treatment-emergent adverse events.

Results

Forty-five studies were analyzed. The five ASMs and two NIBS decreased seizure frequency from baseline compared with placebo. The 50% responder rates of the five antiseizure drugs were significantly higher than that of placebo, and the ASMs were associated with fewer adverse events than placebo (p < 0.05). The surface under the cumulative ranking analysis revealed that ESL was most effective in decreasing the seizure frequency from baseline, whereas CNB provided the best 50% responder rate. BRV was the best tolerated. No significant publication bias was identified for each outcome index.

Conclusion

The five third-generation ASMs were more effective in controlling seizures than placebo, among which CNB, ESL, and LCM were most effective, and BRV exhibited better safety. Although rTMS and tDCS did not reduce seizure frequency as effectively as the five drugs, their safety was confirmed.

Systematic review registration

PROSPERO, https://www.crd.york.ac.uk/prospero/ (CRD42023441097).

Cenobamate enhances the anticonvulsant effect of other antiseizure medications in the DBA/2 mouse model of reflex epilepsy

Clinical studies documented that cenobamate (CNB) has a marked efficacy compared to other antiseizure medications (ASMs) in reducing focal seizures. To date, different aspects of CNB need to be clarified, including its efficacy against generalized seizures. Similarly, the pattern of drug-drug interactions between CNB and other ASMs also compels further investigation. This study aimed to detect the role of CNB on generalized seizures using the DBA/2 mouse model. We have also studied the effects of an adjunctive CNB treatment on the antiseizure properties of some ASMs against reflex seizures. The effects of this adjunctive treatment on motor performance, body temperature, and brain levels of ASMs were also evaluated. CNB was able to antagonize seizures in DBA/2 mice. CNB, at 5 mg/kg, enhanced the antiseizure activity of ASMs, such as diazepam, clobazam, levetiracetam, perampanel, phenobarbital, topiramate, and valproate. No synergistic effects were observed when CNB was co-administered with some Na+ channel blockers. The increase in antiseizure activity was associated with a comparable intensification in motor impairment; however, the therapeutic index of combined treatment of ASMs with CNB was more favorable than the combination with vehicle except for carbamazepine, phenytoin, and oxcarbazepine. Since CNB did not significantly influence the brain levels of the ASMs studied, we suggest that pharmacokinetic interactions seem not probable. Overall, this study shows the ability of CNB to counteract generalized reflex seizures in mice. Moreover, our data documented an evident synergistic antiseizure effect for the combination of CNB with ASMs including phenobarbital, benzodiazepines, valproate, perampanel, topiramate, and levetiracetam.

Brain tumor-related epilepsy management: A Society for Neuro-oncology (SNO) consensus review on current management

Tumor-related epilepsy (TRE) is a frequent and major consequence of brain tumors. Management of TRE is required throughout the course of disease and a deep understanding of diagnosis and treatment is key to improving quality of life. Gross total resection is favored from both an oncologic and epilepsy perspective. Shared mechanisms of tumor growth and epilepsy exist, and emerging data will provide better targeted therapy options. Initial treatment with antiseizure medications (ASM) in conjunction with surgery and/or chemoradiotherapy is typical. The first choice of ASM is critical to optimize seizure control and tolerability considering the effects of the tumor itself. These agents carry a potential for drug-drug interactions and therefore knowledge of mechanisms of action and interactions is needed. A review of adverse effects is necessary to guide ASM adjustments and decision-making. This review highlights the essential aspects of diagnosis and treatment of TRE with ASMs, surgery, chemotherapy, and radiotherapy while indicating areas of uncertainty. Future studies should consider the use of a standardized method of seizure tracking and incorporating seizure outcomes as a primary endpoint of tumor treatment trials.

Research Status, Synthesis and Clinical Application of Antiepileptic Drugs

According to the 2017 ILAE's official definition, epilepsy is a slow brain disease state characterized by recurrent episodes. Due to information released by ILAE in 2017, it can be divided into four types, including focal epilepsy, generalized epilepsy, combined generalized, and focal epilepsy, and unknown epilepsy. Since 1989, 24 new antiepileptic drugs have been approved to treat different types of epilepsy. Besides, there are a variety of antiepileptic medications under clinical monitoring. These novel antiepileptic drugs have plenty of advantages. Over the past 33 years, there have been many antiepileptic drugs on the mearket, but no one has been found that can completely cure epilepsy. In this paper, the mentioned drugs were classified according to their targets, and the essential information, and clinical studies of each drug were described. The structure-activity relationship of different chemical structures was summarized. This paper provides help for the follow-up research on epilepsy drugs.

Cenobamate as add-on therapy for drug resistant epilepsies: effectiveness, drug to drug interactions and neuropsychological impact. What have we learned from real word evidence?

Background: Cenobamate (CNB) is an anti-seizure medication (ASM) approved in 2021 in Europe for adjunctive treatment of focal-onset seizures in adults who were not adequately controlled with at least two previous ASMs. Methods: seizure outcome, treatment-emergent adverse events, neuropsychological profile, and blood levels of CNB and concomitant ASM were analyzed in a real world setting in two different Italian epilepsy centers in the context of CNB early access program. All patients performed a general cognitive evaluation, while 32 patients underwent the administration of a battery of neuropsychological tests at baseline and 6 months after CNB treatment. We performed CNB quantification in plasma in 31 patients at different doses in the range of 100-400 mg/day (65 measures). Results: we enrolled 54 patients with a median age of 27.9 years. The mean follow-up was 10.7 months. Most (91%) completed the efficacy analysis. At last follow-up visit, a 69.5% median seizure reduction was registered. Thirty-two patients (59.2%) had a ≥50% reduction of seizures that was ≥75% in 20 (42.0%) cases, whilst 10 (20.2%) patients were seizure-free. The most common adverse events were somnolence (53.1%), dizziness (28.1%) and diplopia (12.5%). The correlation between CNB dose and plasma concentration, revealed a significant linear correlation (r = 0.86, p < 0.0001), and there was a significant difference in mean plasma concentration/dose administered ratio (C/D ratio) between patients taking or not at least one inducer (0.10 ± 0.04 [(μg/mL)/(mg/day)]; n = 47 vs. 0.13 ± 0.05 [(μg/mL)/(mg/day)]; n = 18, p = 0.04). CNB dose was inversely correlated (r = -0.31, p = 0.02) to the C/D ratio of Carbamazepine blood levels. and positively correlated (r = 0.74, p < 0.0001) with an increased plasma concentration of the active Clobazam metabolite N-desmethylclobazam. General Anxiety Disorder-7 showed a significant improvement of score from baseline evaluation of 6.82 to follow-up 6 months evaluation of 4.53 (p = 0.03). Conclusion: In this real-world study, we registered a clinically meaningful reduction in seizure frequency after CNB administration in most patients along with a good tolerability profile. CNB treatment is correlate to a reduction in symptom severity of anxiety score. Plasma levels measurements confirm that CNB acts both as "victim" and as "perpetrator" of drug-drug interactions.

Cenobamate in refractory epilepsy: Overview of treatment options and practical considerations

Management of drug resistant epilepsy (DRE) represents a challenge to the treating clinician. This manuscript addresses DRE and provides an overview of treatment options, medical, surgical, and dietary. It addresses treatment strategies in polytherapy, then focuses on the role cenobamate (CNB) may play in reducing the burden of DRE while providing practical advice for its introduction. CNB is a recently approved, third generation, anti-seizure medication (ASM), a tetrazole-derived carbamate, thought to have a dual mechanism of action, through its effect on sodium channels as well as on GABAA receptors at a non-benzodiazepine site. CNB, having a long half-life, is an effective add-on ASM in refractory focal epilepsy with a higher response rate and a higher seizure-freedom rate than is usually seen in regulatory clinical trials. Experience post-licensing, though still limited, supports the findings of clinical trials and is encouraging. Its spectrum of action in relation to generalized epilepsies and seizures remains to be established, and there are no data on its efficacy in monotherapy. At the time of writing, CNB has been prescribed for some 50 000 individuals with DRE and focal epilepsy. A larger number is needed to fully establish its safety profile. It should at all times be introduced slowly to minimize the risk of serious allergic drug reactions. It has clinically meaningful interactions which must be anticipated and managed to maximize tolerability and likelihood of successful treatment. Despite the above, it may well prove to be of major benefit in the treatment of many patients with drug resistant epilepsy.

Real-world analysis of retention on cenobamate in patients with epilepsy in the United States

BACKGROUND

This retrospective, observational study used US claims data to assess retention rates on cenobamate compared with four branded antiseizure medications (ASMs) in patients with epilepsy.

METHODS

Adults (≥18 years) with prevalent epilepsy (ICD-10 code G40.xx) and ≥ 1 prescription for cenobamate or any of the newer branded ASMs (brivaracetam, eslicarbazepine, lacosamide, or perampanel) between May 1, 2020 and December 31, 2021 were identified from the HealthVerity Marketplace database. At least 360 days of continuous enrollment was required before and after the index date (Day 1 of initiating cenobamate or branded ASM). Patients were followed until cessation of cenobamate or branded ASM or the end of data collection using Kaplan-Meier methods. Retention was compared between cenobamate and the branded ASMs (both as a group and individually) using Chi-square tests.

RESULTS

In total, 4109 patients were included (195 cenobamate; 3914 branded ASMs). A higher proportion of patients in the cenobamate group compared with the branded ASMs group had concurrent focal and generalized epilepsy (65.6% vs 40.0%) and were on ≥ 3 concomitant ASMs (48.2% vs 12.8%) at the index date. Median time to discontinuation (i.e., the time that half the patients discontinued) was not quite reached after 12 months in the cenobamate group (50.3% of patients remained on cenobamate) and was 7.7 months in the branded ASMs group. Retention was significantly higher with cenobamate vs the branded ASMs group (p = 0.04545) and vs the individual ASMs lacosamide (p = 0.03044) and perampanel (p = 0.01558). Twelve-month retention rates (95% confidence intervals) were 50.3% (43.1%-57.0%) for cenobamate, 40.5% (38.9%-42.0%) for branded ASMs overall, 42.3% (38.6%-46.0%) for brivaracetam, 44.1% (39.2%-49.0%) for eslicarbazepine, 39.9% (38.0%-41.8%) for lacosamide, and 36.8% (31.9%-41.8%) for perampanel.

CONCLUSIONS

In this real-world analysis, retention was significantly higher with cenobamate vs a pooled group of four branded ASMs despite a greater frequency of patients in the cenobamate group having characteristics of more difficult-to-treat epilepsy.

Real-world experience with cenobamate: A systematic review and meta-analysis

PURPOSE

Despite many new ASM, the rate of patients with drug-resistant epilepsy (DRE) has not changed. Cenobamate (CNB) is a novel ASM for the treatment of focal-onset seizures in adults with high seizure freedom rates in randomized controlled trials (RCT). Although CNB appears to be effective, it is not commonly prescribed to patients with DRE, resulting in a lack of "real-world data".

METHODS

To evaluate the real-world effect of CNB and to assess the generalizability of RCT data, a systematic review and meta-analysis was conducted. Pooled proportions were calculated using a random intercept logistic regression model.

RESULTS

The analysis included seven studies with a total of 229 patients with DRE, 77.3 % of whom were adults and 91.5 % had focal-onset seizures. Seizure reduction >50 % was achieved in 68 % of patients [54.54; 79.07], with seizure freedom in 16.2 % [8.38; 28.97]. There was no difference between pediatric and adult patients. CNB was discontinued in 10 % [6.74; 14.6] of patients, mostly due to lack of efficacy (39 %) or adverse effects (AE, 43 %). AE, observed in 57.3 % [39.7; 73.2] of patients, included fatigue and vertigo. A comparison of the rates calculated in this meta-analysis to the active arm of equivalent RCTs revealed no significant difference.

CONCLUSION

CNB achieves a good treatment response in patients with DRE in real-world settings, like the effect reported in RCTs. The high heterogeneity between studies calls for studies focusing on specific DRE subpopulations.

Cenobamate: Real-World Experience Matches Clinical Trials

Adjunctive Cenobamate in Highly Active and Ultra-Refractory Focal Epilepsy: A “Real-World” Retrospective Study Pena-Ceballos J, Moloney PB, Munteanu T, Doyle M, Colleran N, Liggan B, Breen A, Murphy S, El-Naggar H, Widdess-Walsh P, Delanty N. Epilepsia . 2023;64(5):1225-1235. doi:10.1111/epi.17549 Objective: Recent clinical trials have shown that cenobamate substantially improves seizure control in focal-onset drug-resistant epilepsy (DRE). However, little is known about cenobamate’s performance in highly active (≥20 seizures/month) and ultra-refractory focal epilepsy (≥6 failed epilepsy treatments, including antiseizure medications [ASMs], epilepsy surgery, and vagus nerve stimulation). Here, we studied cenobamate’s efficacy and tolerability in a “real-world” severe DRE cohort. Methods: We conducted a single-center retrospective analysis of consecutive adults treated with cenobamate between October 2020 and September 2022. All patients received cenobamate through an Early Access Program. Cenobamate retention, seizure outcomes, treatment-emergent adverse events, and adjustments to concomitant ASMs were analyzed. Results: Fifty-seven patients received cenobamate for at least 3 months (median duration, 11 months). The median cenobamate dose was 250 mg/day (range 75–350 mg). Baseline demographics were consistent with highly active (median seizure frequency, 60/month) and ultra-refractory epilepsy (median previously failed ASMs, nine). Most (87.8%) had prior epilepsy surgery and/or vagus nerve stimulation. Six patients stopped cenobamate due to lack of efficacy and/or adverse events. One patient died from factors unrelated to cenobamate. Among patients who continued cenobamate, three achieved seizure freedom (5.3% of cohort), 24 had a 75%–99% reduction in seizures (42.1% of cohort), and 16 had a 50%–74% reduction (28.1% of cohort). Cenobamate led to abolition of focal to bilateral tonic–clonic seizures in 55.6% (20/36) of patients. Among treatment responders, 67.4% (29/43) were treated with cenobamate doses of ≥250 mg/day. Three-fourths of patients reported at least one side-effect, most commonly fatigue and somnolence. Adverse events most commonly emerged at cenobamate doses of ≥250 mg/day. Side-effects were partially manageable by reducing the overall ASM burden, most often clobazam, eslicarbazepine, and perampanel. Significance: Patients with highly active and ultra-refractory focal epilepsy experienced meaningful seizure outcomes on cenobamate. Emergence of adverse events at doses above 250 mg/day may limit the potential for further improvements in seizure control at higher cenobamate doses.

Further advances in epilepsy

In 2017, one of us reviewed advances in epilepsy (Manford in J Neurol 264:1811-1824, 2017). The current paper brings that review up to date and gives a slight change in emphasis. Once again, the story is of evolution rather than revolution. In recognition that most of our current medications act on neurotransmitters or ion channels, and not on the underlying changes in connectivity and pathways, they have been renamed as antiseizure (ASM) medications rather than antiepileptic drugs. Cenobamate is the one newly licensed medication for broader use in focal epilepsy but there have been a number of developments for specific disorders. We review new players and look forward to new developments in the light of evolving underlying science. We look at teratogenicity; old villains and new concerns in which clinicians play a vital role in explaining and balancing the risks. Medical treatment of status epilepticus, long without evidence, has benefitted from high-quality trials to inform practice; like buses, several arriving at once. Surgical treatment continues to be refined with improvements in the pre-surgical evaluation of patients, especially with new imaging techniques. Alternatives including stereotactic radiotherapy have received further focus and targets for palliative stimulation techniques have grown in number. Individuals' autonomy and quality of life continue to be the subject of research with refinement of what clinicians can do to help persons with epilepsy (PWE) achieve control. This includes seizure management but extends to broader considerations of human empowerment, needs and desires, which may be aided by emerging technologies such as seizure detection devices. The role of specialist nurses in improving that quality has been reinforced by specific endorsement from the International League against Epilepsy (ILAE).

The burden of chronic drug-refractory focal onset epilepsy: Can it be prevented?

Despite the many therapeutic options for epilepsy available today, a third of patients still have poorly controlled epilepsy. Over the years, their transition through lines of treatment exposes them to increased risk of disease progression, mortality, morbidity, mental distress, and not least significantly impaired quality of life (QoL). The present review explores the multiple factors contributing to the impairment of health-related QoL in PWE-including both seizure-related and non seizure-related. The analysis aims to identify potential areas of intervention and strategies for a more holistic approach to epilepsy care and inform policy-makers and healthcare providers in their approach to this condition.

Cenobamate and Clobazam Combination as Personalized Medicine in Autoimmune-Associated Epilepsy With Anti-Gad65 Antibodies

BACKGROUND AND OBJECTIVES

Autoimmune-associated epilepsy (AAE) with antiglutamic acid decarboxylase 65 (GAD65) antibodies is considered a T-cell-mediated encephalitis that evolves to drug-resistant epilepsy. We do not have an effective therapeutic strategy for these patients. Because the GAD enzyme is primarily responsible for the conversion of glutamate to GABA, the mechanism of epileptogenesis in this condition predicts decreased levels of GABA content in synaptic vesicles. Cenobamate (CNB) acts as a positive allosteric modulator at synaptic and extra synaptic GABAA receptors, producing increased inhibitory neurotransmission in the brain. This mechanism could be especially beneficial in AAE with anti-GAD65 antibodies because it would be able to correct the imbalance due to the GABAergic stimulation deficit in postsynaptic neurons.

METHODS

We recruit a retrospective multicentric consecutive case series of AAE with anti-GAD65 antibodies from 5 epilepsy units in Spain who have received treatment with CNB.

RESULTS

A total of 8 patients were recruited. This cohort of highly refractory patients have failed a mean of 9.50 (SD = 3.20) ASM without control of seizures for sustained periods of time. The average number of seizures per month during the previous 3 months before CNB treatment was 19.63 (SD = 17.03). After the introduction of CNB improvement was achieved in all our patients, with a median reduction in the number of seizures of 92.22% (interquartile range [IQR]: 57.25-98.75). The mean follow-up was 156.75 days (SD = 68.23). In patients with concomitant treatment with clobazam (CLB), the median percentage of seizure reduction was higher than those not taking CLB: 94.72% (IQR: 87.25-100) vs 41.50% (p = 0.044) and also higher than the control group of patients with refractory epilepsy not related to anti-GAD65 treated with the same combination: 94.72% (IQR: 87.25-100) vs 45.00% (IQR: 25.00-87.00) (p = 0.019).

DISCUSSION

Treatment with the combination CNB + CLB could be a type of personalized medicine in patients with AAE with anti-GAD65. Our preliminary data will need to be endorsed with new prospective and controlled studies.

Dose reduction and discontinuation of concomitant antiseizure medications after initiating cenobamate: A retrospective review

This retrospective chart review examined dose reductions and discontinuations of concomitant antiseizure medications (ASMs) following cenobamate initiation and maintenance in patients with epilepsy treated at MetroHealth (Cleveland, OH) between 9/1/2020-9/26/2022. Concomitant ASM dose adjustments and treatment-emergent adverse events (TEAEs) were assessed. Efficacy (100 % seizure reduction) was examined among patients who received cenobamate for ≥ 3 months at data cutoff (including titration). As of 9/26/2022, 95 patients received cenobamate (mean age, 45.9 years; 48.4 % female, median exposure 7.5 months). Five patients (5.3 %) discontinued (n = 1 withdrawal by patient; n = 1 noncompliance; n = 3 adverse event). Among the 90 patients taking cenobamate at data cutoff, 50 % (45/90) discontinued ≥ 1 concomitant ASM, most commonly clobazam (n = 18), levetiracetam (n = 10), and phenytoin (n = 7); 21 patients (23.3 %) had additional concomitant ASM dose reductions, most commonly phenytoin (n = 6) and clobazam (n = 4). Sixteen patients received cenobamate monotherapy. Among 79 patients who received cenobamate for ≥ 3 months at data cutoff, 51.9 % (41/79) were seizure-free for ≥ 3 months. Of the 41 seizure-free patients, 58.5 % (24/41) were taking 100 mg/day of cenobamate. Sixteen of the 95 cenobamate-treated patients (16.8 %) reported 22 TEAEs. The most common TEAE was fatigue (n = 7). These data suggest that cenobamate therapy may allow reduction or elimination of polytherapy in some patients.

Sustainability of seizure reduction and seizure control with adjunctive cenobamate: Post hoc analysis of a phase 3, open-label study

OBJECTIVE

In this post hoc analysis of a subset of patients from a long-term, open-label phase 3 study, we assessed ≥50%, ≥75%, ≥90%, and 100% seizure reduction and sustainability of these responses with cenobamate using a time-to-event analytical approach.

METHODS

Of 240 patients with uncontrolled focal seizures who had adequate seizure data available, 214 completed the 12-week titration phase and received ≥1 dose of cenobamate in the maintenance phase (max dose 400 mg/day) and were included in this post hoc analysis. Among patients who met an initial given seizure-reduction level (≥50%, ≥75%, ≥90%, or 100%), sustainability of that response was measured using a time-to-event methodology. An event was defined as the occurrence of a study visit at which the seizure frequency during the interval since the prior study visit exceeded the initially attained reduction level. Study visits during the maintenance phase occurred at 3-month intervals.

RESULTS

Of the 214 patients analyzed, 188 (88%), 177 (83%), 160 (75%), and 145 (68%) met ≥50%, ≥75%, ≥90%, and 100% seizure-reduction responses, respectively, for at least one study visit interval during the maintenance phase. The median (95% confidence interval [CI]) time to first visit without a ≥50% seizure reduction was not reached by 30 months of follow-up (53% of patients maintained their initial ≥50% seizure reduction). Median (95% CI) time to first visit without sustaining the initial ≥75%, ≥90%, or 100% seizure reduction was 13.0 (7.5-21.9) months, 7.5 (5.4-11.6) months, and 7.0 (5.3-10.4) months, respectively. Among the 145 patients who had 100% seizure reduction during at least one study visit, 22% remained seizure-free for at least 30 months and 63% had ≤3 study visits with seizures.

SIGNIFICANCE

Adjunctive treatment with cenobamate led to sustained seizure reductions during the maintenance phase of the phase 3 safety study.

Cenobamate in patients with highly refractory focal epilepsy: A retrospective real-world study

PURPOSE

To determine the effectiveness and safety outcomes of cenobamate in a cohort of patients with highly refractory focal epilepsy in routine clinical practice.

METHODS

Observational, retrospective, phase 4 study on subjects receiving cenobamate in three Spanish centers. The primary endpoint was the retention rate at the last follow-up. The main secondary endpoints were the 50%-responder  and seizure-free rates at three months and the last follow-up. Other secondary endpoints were Global Clinical Impressions-Improvement (CGI-I) scores and treatment-emergent adverse events (TEAEs).

RESULTS

Fifty-one patients with highly refractory focal epilepsy with 24.7 years of disease evolution, ten previously tried ASM, and a 23.5% of previous epilepsy surgery were included. The retention rate at the last follow-up was 80.4%. The 50% responder rate in focal seizures at three months was 56.5% (median reduction per month 51%, 0-74.6; p < 0.0001) and in focal to bilateral tonic-clonic seizures was 63.6% (median reduction per month 89%, 0-100; p = 0.022). A total of 54.3% of subjects reported a reduction in the intensity of focal seizures, and 66% manifested clinically significant satisfaction. Cenobamate allowed a significant decrease in concomitant ASM, especially sodium channel blockers. TEAEs were reported in 43.1% of individuals, 85% of whom resolved or improved, with no new safety findings.

CONCLUSION

In this analysis of patients with highly refractory focal epilepsy treated with cenobamate according to standard clinical practice, there was evidence of a high reduction in both seizure frequency and intensity, with a manageable safety profile.

Increasing challenges to trial recruitment and conduct over time

OBJECTIVE

This study was undertaken to evaluate how the challenges in the recruitment and retention of participants in clinical trials for focal onset epilepsy have changed over time.

METHODS

In this systematic analysis of randomized clinical trials of adjunct antiseizure medications for medication-resistant focal onset epilepsy, we evaluated how the numbers of participants, sites, and countries have changed since the first such trial in 1990. We also evaluated the proportion of participants who completed each trial phase and their reasons for early trial exit. We analyzed these trends using mixed effects generalized linear models accounting for the influence of the number of trial sites and trial-specific variability.

RESULTS

The number of participants per site has steadily decreased over decades, with recent trials recruiting fewer than five participants per site (reduction by .16 participants/site/year, p < .0001). Fewer participants also progressed from recruitment to randomization over time (odds ratio = .94/year, p = .014). Concurrently, there has been an increase in the placebo response over time (increase in median percent reduction of .4%/year, p = .02; odds ratio of increase in 50% responder rate of 1.03/year, p = .02), which was not directly associated with the number of sites per trial (p > .20).

SIGNIFICANCE

This historical analysis highlights the increasing challenges with participant recruitment and retention, as well as increasing placebo response. It serves as a call to action to change clinical trial design to address these challenges.

Drug-resistant epilepsy: Definition, pathophysiology, and management

There are currently >51 million people with epilepsy (PWE) in the world and every year >4.9 million people develop new-onset epilepsy. The cornerstone of treatment in PWE is drug therapy with antiseizure medications (ASMs). However, about one-third of PWE do not achieve seizure control and do not respond well to drug therapy despite the use of appropriate ASMs [drug-resistant epilepsy (DRE)]. The aims of the current narrative review are to discuss the definition of DRE, explain the biological underpinnings and clinical biomarkers of this condition, and finally to suggest practical management strategies to tackle this issue appropriately, in a concise manner.