Long-term safety of adjunctive cenobamate in patients with uncontrolled focal seizures: Open-label extension of a randomized clinical study

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.

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.

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.

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).

Treatment simplification to optimize cenobamate effectiveness and tolerability: A real-world retrospective study in Spain

OBJECTIVE

This study aimed to explore the impact of co-antiseizure medication (co-ASM) optimization on the effectiveness and tolerability of adjunctive cenobamate (CNB) in patients with drug-resistant epilepsy in a real-world setting.

METHODS

This unicentric, retrospective, observational study included adults with focal-onset seizures who had received ≥2 previous ASMs. The main effectiveness endpoints included responder rates and seizure frequency reduction at 3, 6, and 12-month visits. The number of co-ASMs and defined daily dose (DDD) were analyzed at every visit. Safety endpoints included adverse drug reactions (ADRs).

RESULTS

Thirty-four patients with a median epilepsy duration of 22 years and a median of 15.5 seizures/month were analyzed. The median number of prior ASMs was 12, and the mean number of co-ASMs was 2.9 (SD 1). There was a reduction in seizure frequency/month from baseline to the last visit (p < 0.0001). Between baseline and the end of the study, the mean number of co-ASMs in the per-protocol (PP) population was reduced from 2.9 to 1.6 (p < 0.0001), and DDD was reduced from 3.6 to 1.4 (p < 0.0001). Sodium channel blockers (carbamazepine and lacosamide) and GABAergic drugs (clobazam) were the agents with the most significant reductions in DDD after 12 months. The percentage of patients in the PP population with ≥3 co-ASMs was reduced from 61.8% at baseline to 14.3% at 12 months; 1 patient was receiving CNB as monotherapy at the last visit. At the last visit, 85.7% of the PP population were ≥50% responders, and 33.3% were seizure-free. The percentage of patients with ADRs in the PP population was 71.9% at 3 months and 52.3% at 12 months.

SIGNIFICANCE

Following rational polytherapy, optimization of co-ASM management during CNB treatment allowed high seizure freedom rates despite meaningful reductions in co-medication, while also achieving both good tolerability and patient satisfaction scores in a highly drug-resistant population.

PLAIN LANGUAGE SUMMARY

Many patients with epilepsy still have seizures, even after being treated with several different epilepsy drugs. In this study of 34 patients from a Spanish clinic, we show that the epilepsy drug cenobamate can reduce the number of seizures in these patients, even after many other epilepsy drugs have failed. We also show that patients treated with cenobamate can reduce the dose or even stop taking certain other epilepsy drugs. This allows them to simplify their treatment and reduce adverse effects while still keeping control of their epilepsy.

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.

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.

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.

Prospective study of cenobamate on cognition, affectivity, and quality of life in focal epilepsy

OBJECTIVE

Cenobamate is a recently approved antiseizure medication that proved to be safe and effective in randomized controlled trials. However, little is known about its impact on some areas frequently affected by epilepsy. For this reason, we explored the effects of cenobamate on cognitive performance, as well as on negative affectivity and quality of life in a sample of patients with drug-resistant epilepsy.

METHODS

Two prospective cohort studies were carried out. In Study 1, 32 patients (22 men and 10 women) underwent a baseline (T0) and a short-term (T1) neuropsychological assessment after 3 months of cenobamate administration. In Study 2, 22 patients (16 men and 6 women) from the T1 sample also underwent a baseline and a follow-up evaluation (T2) 6 months after T0.

RESULTS

No significant differences were found in cognitive variables, negative affectivity, and quality of life either in Study 1 or Study 2. Similarly, based on the reliable change index, it was found that most patients showed no changes in these variables.

SIGNIFICANCE

These results suggest that cenobamate is a safe antiseizure medication in terms of cognition, negative affectivity, or quality of life since no adverse events have been found after 3 and 6 months of treatment.

PLAIN LANGUAGE SUMMARY

Cenobamate is a new antiseizure medication. In patients with epilepsy, cenobamate seems to not affect cognition, anxiety, depression, or quality of life.

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.

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.

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).

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.

Real-world safety and effectiveness of cenobamate in patients with focal onset seizures: Outcomes from an Expanded Access Program

OBJECTIVE

This study investigated early, real-world outcomes with cenobamate (CNB) in a large series of patients with highly drug-resistant epilepsy within a Spanish Expanded Access Program (EAP).

METHOD

This was a multicenter, retrospective, observational study in 14 hospitals. Inclusion criteria were age ≥18 years, focal seizures, and EAP authorization. Data were sourced from patient clinical records. Primary effectiveness endpoints included reductions (100%, ≥90%, ≥75%, and ≥50%) or worsening in seizure frequency at 3-, 6-, and 12-month visits and at the last visit. Safety endpoints included rates of adverse events (AEs) and AEs leading to discontinuation.

RESULTS

The study included 170 patients. At baseline, median epilepsy duration was 26 years and median number of seizures/month was 11.3. The median number of prior antiseizure medications (ASMs) and concomitant ASMs were 12 and 3, respectively. Mean CNB dosages/day were 176 mg, 200 mg, and 250 mg at 3, 6, and 12 months. Retention rates were 98.2%, 94.5%, and 87% at 3, 6, and 12 months. At last available visit, the rate of seizure freedom was 13.3%; ≥90%, ≥75%, and ≥50% responder rates were 27.9%, 45.5%, and 63%, respectively. There was a significant reduction in the number of seizures per month (mean: 44.6%; median: 66.7%) between baseline and the last visit (P < 0.001). Responses were maintained regardless of the number of prior or concomitant ASMs. The number of concomitant ASMs was reduced in 44.7% of patients. The cumulative percentage of patients with AEs and AEs leading to discontinuation were 68.2% and 3.5% at 3 months, 74.1% and 4.1% at 6 months, and 74.1% and 4.1% at 12 months. The most frequent AEs were somnolence and dizziness.

SIGNIFICANCE

In this highly refractory population, CNB showed a high response regardless of prior and concomitant ASMs. AEs were frequent but mostly mild-to-moderate, and few led to discontinuation.

Pharmacokinetics of cenobamate as monotherapy compared with adjunctive therapy

OBJECTIVE

Cenobamate was approved by the US Food and Drug Administration (FDA) based on studies of adjunctive therapy in patients with focal epilepsy. To support the use of cenobamate monotherapy, this pharmacokinetic (PK)-based simulation analysis evaluated the predicted PK exposure of cenobamate when used as monotherapy versus adjunctive therapy.

METHODS

A population pharmacokinetic (PopPK) model of cenobamate was developed using pooled human data from eight phase 1 studies in healthy subjects or special populations, and three phase 2 and 3 studies in patients with focal seizures (N = 960). Concomitant antiseizure medications (ASMs) with a statistically significant effect on the apparent systemic clearance (CL/F) of cenobamate in the PopPK model were used to compare simulated patient plasma exposures (area under the plasma concentration vs time curve [AUC]) following monotherapy versus adjunctive therapy. Treatment equivalence between monotherapy and adjunctive therapy was concluded if the 90% confidence interval (CI) of the geometric mean AUC ratio was within 0.8-1.25.

RESULTS

In the PopPK model, statistically significant effects on cenobamate CL/F were shown for clobazam (decreased cenobamate CL/F by 19%) and carbamazepine (increased cenobamate CL/F by 15%); these differences were not considered clinically meaningful. Other ASMs (lacosamide, lamotrigine, levetiracetam, oxcarbazepine, topiramate, and valproate) when coadministered with cenobamate did not have significant effects on the disposition (ie, PK or efficacy) of cenobamate. The geometric mean ratio (90% CIs) of cenobamate AUC for adjunctive therapy/monotherapy was 0.87 (0.816-0.925) for adjunctive carbamazepine and 1.24 (1.147-1.339) for adjunctive clobazam. The 90% CI was within the no-effect limits (90% CIs 0.8-1.25) for adjunctive carbamazepine and partially exceeding no-effect limits for adjunctive clobazam.

CONCLUSIONS

Based on the results from this PopPK analysis, cenobamate monotherapy can be expected to result in comparable exposures to those that have been demonstrated to be safe and effective when used as adjunctive therapy for the treatment of focal seizures, supporting the use of cenobamate as monotherapy in these patients.

Sudden unexpected death in epilepsy during cenobamate clinical development

OBJECTIVE

We assessed mortality, sudden unexpected death in epilepsy (SUDEP), and standardized mortality ratio (SMR) among adults treated with cenobamate during the cenobamate clinical development program.

METHODS

We retrospectively analyzed deaths among all adults with uncontrolled focal (focal to bilateral tonic-clonic [FBTC], focal impaired awareness, focal aware) or primary generalized tonic-clonic (PGTC) seizures who received ≥1 dose of adjunctive cenobamate in completed and ongoing phase 2 and 3 clinical studies. In patients with focal seizures from completed studies, median baseline seizure frequencies ranged from 2.8 to 11 seizures per 28 days and median epilepsy duration ranged from 20 to 24 years. Total person-years included all days that a patient received cenobamate during completed studies or up to June 1, 2022, for ongoing studies. All deaths were evaluated by two epileptologists. All-cause mortality and SUDEP rates were expressed per 1000 person-years.

RESULTS

A total of 2132 patients (n = 2018 focal epilepsy; n = 114 idiopathic generalized epilepsy) were exposed to cenobamate for 5693 person-years. Approximately 60% of patients with focal seizures and all patients in the PGTC study had tonic-clonic seizures. A total of 23 deaths occurred (all in patients with focal epilepsy), for an all-cause mortality rate of 4.0 per 1000 person-years. Five cases of definite or probable SUDEP were identified, for a rate of .88 per 1000 person-years. Of the 23 overall deaths, 22 patients (96%) had FBTC seizures, and all 5 of the SUDEP patients had a history of FBTC seizures. The duration of exposure to cenobamate for patients with SUDEP ranged from 130 to 620 days. The SMR among cenobamate-treated patients in completed studies (5515 person-years of follow-up) was 1.32 (95% confidence interval [CI] .84-2.0), which was not significantly different from the general population.

SIGNIFICANCE

These data suggest that effective long-term medical treatment with cenobamate may reduce excess mortality associated with epilepsy.

Cenobamate (YKP3089) and Drug-Resistant Epilepsy: A Review of the Literature

Cenobamate (CNB), ([(R)-1-(2-chlorophenyl)-2-(2H-tetrazol-2-yl)ethyl], is a novel tetrazole alkyl carbamate derivative. In November 2019, the Food and Drug Administration approved Xcopri®, marketed by SK Life Science Inc., (Paramus, NJ, USA) for adult focal seizures. The European Medicines Agency approved Ontozry® by Arvelle Therapeutics Netherlands B.V.(Amsterdam, The Neatherlands) in March 2021. Cenobamate is a medication that could potentially change the perspectives regarding the management and prognosis of refractory epilepsy. In this way, this study aims to review the literature on CNB's pharmacological properties, pharmacokinetics, efficacy, and safety. CNB is a highly effective drug in managing focal onset seizures, with more than twenty percent of individuals with drug-resistant epilepsy achieving seizure freedom. This finding is remarkable in the antiseizure medication literature. The mechanism of action of CNB is still poorly understood, but it is associated with transient and persistent sodium currents and GABAergic neurotransmission. In animal studies, CNB showed sustained efficacy and potency in the 6 Hz test regardless of the stimulus intensity. CNB was revealed to be the most cost-effective drug among different third-generation antiseizure medications. Also, CNB could have neuroprotective effects. However, there are still concerns regarding its potential for abuse and suicidality risk, which future studies should clearly assess, after which protocols should be changed. The major drawback of CNB therapy is the slow and complex titration and maintenance phases preventing the wide use of this new agent in clinical practice.

Adjunctive cenobamate in highly active and ultra-refractory focal epilepsy: A "real-world" retrospective study

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.

Cenobamate in Generalized Epilepsy and Combined Generalized and Focal Epilepsy

Background and Objectives

Cenobamate (CNB) is a United States Food and Drug Administration–approved antiseizure medication (ASM) for focal-onset seizures; however, its potential clinical effectiveness as a broad-spectrum ASM is not established. CNB has a proposed dual mechanism of action with preferential blockade of persistent sodium currents and positive allosteric modulation of the γ-aminobutyric acid-A (GABA-A) receptor. We evaluated the efficacy of CNB in drug refractory patients with genetic generalized epilepsies (GGE) or combined generalized and focal epilepsies (CGFE), including developmental and epileptic encephalopathies.

Methods

We performed a retrospective review and identified the following: cohort 1 (n = 4) with GGE, of which 2 patients had idiopathic generalized epilepsy, and cohort 2 with CGFE (n = 9), of which 4 patients had Lennox-Gastaut syndrome and 1 had Dravet syndrome.

Results

In cohort 1, all 3 patients with frequent generalized tonic-clonic seizures (GTCs) had a greater than 50% reduction in GTCs. In cohort 2, reduction in both generalized and focal-onset seizures was noted. In these groups together, the mean reduction of all seizure types was 58%, and ≥50% responder rate was 70% (SD = ±34.16, median = 50%). No worsening of generalized-onset seizures occurred in either cohort. Seventy-seven percent of patients experienced side effects, warranting a modification of treatment managed by slower titration, dose reduction of CNB, or discontinuing other ASMs.

Discussion

In our retrospective case series, CNB seems to be an effective ASM for patients with drug-resistant GGE and CGFE. The ongoing CNB trial assessing effectiveness for primary GTCs will provide more data on generalized-onset seizures.

Classification of Evidence

This study provides Class IV evidence that CNB in generalized epilepsy and combined generalized and focal epilepsy reduces seizure frequency.

Scoping review of rational polytherapy in patients with drug-resistant epilepsy

There is a paucity of literature regarding the optimal selection of combination antiseizure medications (ASMs) for drug-resistant epilepsy (DRE). The aim of this scoping review is to evaluate current evidence related to "rational polytherapy" among adults with DRE. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Scoping Reviews (PRISMA-SCr) guidelines, PubMed, ProQuest, CINAHL, and Cochrane databases were searched using DRE- and polytherapy-related keywords. The exclusion criteria applied included: non-English; non-human studies; non-research studies; participants less than 18 years; status epilepticus; ASM monotherapy; and certain ASMs. In Covidence, two researchers independently reviewed articles for inclusion at each phase, with a third resolving conflicts. Data were extracted, with quality appraisal using the Mixed Methods Appraisal Tool (MMAT). Of the 6477 studies imported for screening, 33 studies were included. Clinical, humanistic, and economic outcomes were reported by 26, 12, and one study, respectively. Common efficacy-related clinical outcomes included ≥50% reduction in seizure frequency (n = 14), seizure freedom (n = 14), and percent reduction in seizure frequency (n = 8). Common humanistic outcomes included quality of life (n = 4), medication adherence (n = 2), sleep-related outcomes (n = 2), and physician and patient global assessments (n = 2). The economic study reported quality-adjusted life years. The median MMAT score was 80 (range: 60-100). Two studies referenced the standard definition of DRE, whereas five studies did not specifically define DRE. Gaps in the literature include limited generalizability, minimal reports in pregnancy, and lack of optimal ASM combinations, among others. Strengths of the evidence include addressing a variety of outcomes. Inconsistent definitions of DRE, small sample sizes, and heterogeneity among studies limit the ability to draw meaningful conclusions. Optimal combinations of ASMs for rational polytherapy for DRE is unclear.

Use of cenobamate for the treatment of focal epilepsy: an Italian expert opinion paper

INTRODUCTION

Cenobamate is a new antiseizure medication (ASM) recently introduced in the USA for the treatment of adults with focal-onset seizures. In March 2021, the European Commission authorized its use for the adjunctive treatment of focal-onset seizures with or without secondary generalization (focal seizures with or without progression to bilateral tonic-clonic seizures, according to current ILAE terminology) in adults with epilepsy not adequately controlled despite the treatment with at least two ASMs.

AREAS COVERED

This review summarizes the mechanism of action, efficacy, and safety of Cenobamate. The authors provide their expert opinions on the use of this drug.

EXPERT OPINION

The aim of this paper is to report on the Italian preliminary experience with the use of cenobamate, focusing on treatment goals, optimal dosing and titration schedules, strategies to minimize adverse effects, and identification of suitable candidates for treatment. There was agreement that slow titration may improve tolerability, and that clinically significant benefit can be achieved in many patients at relatively low doses. A favorable response to relatively low doses of cenobamate could be an early predictor of ultimate responsiveness. Overall, cenobamate is a welcome new treatment for adults with focal seizures resistant to conventional ASMs.

Effectiveness and safety of adjunctive cenobamate for focal seizures in adults with developmental disability treated in clinical practice

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92.9% (26/28 patients) continued cenobamate through 6 months, showing high retention.

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High responder rates/substantial focal seizure reduction occurred with cenobamate.

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100% seizure reduction occurred in 48.2% of patients at 6 months.

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Adverse effects were often mitigated by concomitant antiseizure medication reduction.

Effectiveness and tolerability of adjunctive cenobamate for uncontrolled focal seizures in adults living with a developmental disability are not defined. Retrospective medical record review included adults ≥18 years old living with a developmental disability, either in a group home or with parents, and experiencing uncontrolled focal seizures despite stable doses of ≥1 antiseizure medication (ASM). Effectiveness was examined as percentage change in focal seizure frequency per month from the 2-month average before cenobamate to the average of months 5 and 6 while receiving cenobamate. Percentages of patients achieving responder rates in focal seizure frequency at 6 months of cenobamate treatment were examined. Adverse effects and concomitant ASM dosage adjustments were assessed. Of the 28 included patients, 26 (92.9%) continued cenobamate beyond 6 months. The responder rate of 100% seizure reduction (seizure-free) occurred in 48.2% of the patients who continued cenobamate for 6 months. Ten adverse effects were reported in 9 patients (32.1%), and 80% (8/10) were resolved by reducing concomitant ASM dosages. Two patients (7.1%) discontinued cenobamate due to adverse effects. Cenobamate resulted in substantial reduction in focal seizure frequency and was well tolerated.

Is Cenobamate the Breakthrough We Have Been Wishing for?

Close to one-third of patients with epilepsies are refractory to current anti-seizure medications; however, trials with cenobamate suggest effectiveness in such patients with focal onset seizures. We searched for data published or otherwise reported on cenobamate and outlined these here. Despite being marketed in the USA, few studies are yet published in full, and trials are ongoing. Nevertheless, cenobamate showed potential for a high degree of efficacy in reducing seizures with an unprecedented seizure-free rate of up to 28%. Rare cases of hypersensitivity reactions seen in early trials seem to be avoided by the current recommended titration schedule. Other adverse events were rated mild-to-moderate and most commonly included dizziness, drowsiness, and headache. If data are confirmed in further published trials, cenobamate will be a welcome new treatment and further analyses may identify those that will benefit the most.