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

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).

Cenobamate: real-world data from a retrospective multicenter study

OBJECTIVE

To report the effects of adjunctive cenobamate and concomitant antiseizure medications (ASMs) on weight from two double-blind, placebo-controlled, phase 2 studies (YKP3089C013 [C013] and YKP3089C017 [C017]) and their open-label extensions (OLEs) and from a long-term, open-label phase 3 safety study, YKP3089C021 (C021).

BACKGROUND

Cenobamate is an ASM approved in the US and EU for treatment of focal seizures in adults. Some ASMs are associated with weight gain (e.g., valproate, gabapentin, pregabalin), which can negatively affect patient health.

DESIGN/METHODS

Patients with uncontrolled focal seizures taking stable doses of 1-3 ASMs were enrolled in each study. In C013, cenobamate was titrated to a target dose of 200 mg/day (max OLE dose 400 mg/day). In C017, patients were randomized to cenobamate 100, 200, or 400 mg/day (max OLE dose 400 mg/day). In C021, cenobamate was titrated to a target dose of 200 mg/day (max dose 400 mg/day). Median weight changes at 1 and 2 years from baseline were analyzed post hoc.

RESULTS

Analyses included 39, 206, and 1054 patients from C013, C017 (dose groups combined), and C021, respectively. Median weight changes from baseline ranged from -0.2 to -0.9 kg at 1 year and from -1.0 to +1.0 kg at 2 years. Some numerical reductions in weight were noted in patients who discontinued valproate by 1 (-13.0 kg, C013, n=1) or 2 years (-24.5 kg, C017, n=2) and in patients who discontinued gabapentin by 1 (-7.1 kg, C017, n=2) or 2 years (-7.0 kg, C017, n=2). Otherwise, median weight changes from baseline for patients receiving concomitant valproate, gabapentin, or pregabalin ranged from -3.1 to +2.6 kg at 1 year and from -1.6 to +2.7 kg at 2 years.

CONCLUSIONS

Adjunctive cenobamate was not associated with clinically significant changes in weight from baseline in patients treated for 1 and 2 years, including those receiving concomitant valproate, gabapentin, or pregabalin.

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.

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.

Safety assessment of cenobamate: real-world adverse event analysis from the FAERS database

Objective

This study aims to analyze adverse drug events (ADEs) associated with cenobamate from the FAERS database, covering the third quarter of 2020 to the second quarter of 2023.

Methods

Data related to cenobamate-associated ADEs from the third quarter of 2020 to the second quarter of 2023 were collected. After standardizing the data, various signal quantification techniques, including ROR, MHRA, BCPNN, and MGPS, were employed for analysis.

Results

Among 2535 ADE reports where cenobamate was the primary suspected drug, 94 adverse reactions involving 11 different System Organ Class (SOC) categories were identified through the application of four signal quantification techniques. More specifically, neurological disorders and injuries resultant from complications are frequent adverse reactions associated with cenobamate.

Conclusion

Our research findings align with established results, affirming the favorable safety profile of cenobamate. Effective prevention of adverse reactions induced by cenobamate can be achieved through the establishment of efficient blood concentration monitoring and dose adjustments.

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.