Onset of efficacy and adverse events during Cenobamate titration period

Cenobamate: A Review in Focal-Onset Seizures

Cenobamate (Ontozry®) is a once-daily oral antiseizure medication (ASM) approved in the EU for the adjunctive treatment of focal-onset seizures, with or without secondary generalisation, in adults with epilepsy that have not been adequately controlled despite previous treatment with ≥ 2 anti-epileptic drugs. In clinical studies, its short-term use significantly reduced seizure frequency and was associated with significantly higher odds of achieving a ≥ 50% reduction in seizure frequency in adults with uncontrolled focal-onset seizures despite treatment with 1-3 concomitant ASMs. Seizure freedom rates were also improved. All these benefits were sustained over up to 48 months. Cenobamate was generally well tolerated across both the short- and longer-term (up to 94 months) clinical studies, with its low starting dosage (12.5 mg/day) and slow (12-week) titration schedule appearing to result in fewer severe treatment-emergent adverse events (TEAEs) during the titration period. Somnolence, dizziness and fatigue were the most frequently reported TEAEs. The effectiveness and adverse events of cenobamate in real-world studies were consistent with those seen in the clinical studies. Thus, cenobamate continues to represent a useful adjunctive treatment option in adults with uncontrolled focal-onset seizures.

Sodium channel blockers for the treatment of focal epilepsy: A Chinese expert consensus

PURPOSE

To provide consensus-based recommendations for the use of sodium channel blockers (SCBs) in the management of focal epilepsy.

METHODS

A three-round modified Delphi procedure was conducted among a Delphi panel of 24 Chinese experts to build a consensus. A steering committee developed 9 statements related to SCBs for the treatment of focal epilepsy, and these statements were evaluated and voted upon by the expert panel.

RESULTS

The expert panel achieved consensus on nine statements regarding the treatment recommendations for oxcarbazepine, lamotrigine, lacosamide, eslicarbazepine, topiramate, zonisamide and cenobamate in focal epilepsy patients and treatment adjustments for SCBs.

CONCLUSION

This is a Chinese expert consensus on the use of SCBs in focal epilepsy developed using the modified Delphi method. These recommendations can help clinicians in their practice and guide future research.

Real-world effectiveness and tolerability of cenobamate in drug-resistant epilepsy: A retrospective analysis of the patients included into the Early Access Programs (EAP) in Germany, France, and United Kingdom

OBJECTIVE

Investigate real-world outcomes in drug-resistant epilepsy (DRE) patients treated with cenobamate as adjunctive treatment to other antiseizure medications (ASMs) within the Early Access Programs (EAP) in Germany, France, and the United Kingdom.

METHODS

DRE adults with uncontrolled focal-onset seizures were included from 19 hospitals participating in the EAP in this retrospective study. Data were sourced from clinical records. Participants were evaluated at baseline, 1 months, and 3 months from cenobamate start, and 3, 6, and 12 months after maintenance. The primary effectiveness endpoint was the 50% responder rate, defined as the reduction in seizure frequency ≥50%.

RESULTS

Data were collected from 298 patients who received at least one dose of cenobamate; efficacy was evaluated on 216 patients with seizure data available. At baseline, the median epilepsy duration was 22.2 years, and 41.9% of patients had previous epilepsy surgery, including vagus nerve stimulation, with a median of nine previously failed ASMs. The median number of seizures/month was 8.8. After 3 months of maintenance, the 50% responder rate (primary endpoint) was 49.3%; the median percentage seizure reduction from baseline was 49.1%. A total of 100%, ≥90%, and ≥75% seizures reduction were reported in 13.6%, 20.0%, and 33.6% of patients, respectively. Both the responder rate and the median percentage seizure reduction steadily increased during the observation period. At 6-month maintenance, the seizure-free rate was 24.2%. The retention rate assessed by Kaplan-Meier decreased from 96.6% at 1-month cenobamate start to 69.7% at 12-month maintenance. Adverse Drug Reactions (ADRs) to cenobamate occurred in 30.9% of patients, with asthenia, dizziness, and somnolence being the most frequent; the majority were mild-to-moderate and resolved during the observation period; three patients (1.0%) experienced a total of seven serious ADRs, all during titration.

SIGNIFICANCE

In this study, cenobamate demonstrated to be an effective option for people with uncontrolled epilepsy even after multiple failed ASMs or failure of epilepsy surgery.

PLAIN LANGUAGE SUMMARY

This study involved patients with drug-resistant epilepsy, who had continued seizures despite using at least two antiseizure medications (ASMs). Patients received cenobamate (Ontozry) as epilepsy treatment during the Early Access Program (EAP) in France, Germany, and the United Kingdom. An EAP allows patients to receive promising new drugs under clinical supervision before they are commercially available. After 6 months from cenobamate start, 49.3% of patients had their seizures cut by half or more, and 13.6% became seizure-free. A total of 30.9% of patients had an undesirable reaction to cenobamate, mostly mild-to-moderate and resolved; the most frequent were asthenia, dizziness, and somnolence.

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.

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.

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.

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.

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.

New GABA-Targeting Therapies for the Treatment of Seizures and Epilepsy: I. Role of GABA as a Modulator of Seizure Activity and Recently Approved Medications Acting on the GABA System

γ-Aminobutyric acid (GABA) is the most prevalent inhibitory neurotransmitter in the mammalian brain and has been found to play an important role in the pathogenesis or the expression of many neurological diseases, including epilepsy. Although GABA can act on different receptor subtypes, the component of the GABA system that is most critical to modulation of seizure activity is the GABAA-receptor-chloride (Cl-) channel complex, which controls the movement of Cl- ions across the neuronal membrane. In the mature brain, binding of GABA to GABAA receptors evokes a hyperpolarising (anticonvulsant) response, which is mediated by influx of Cl- into the cell driven by its concentration gradient between extracellular and intracellular fluid. However, in the immature brain and under certain pathological conditions, GABA can exert a paradoxical depolarising (proconvulsant) effect as a result of an efflux of chloride from high intracellular to lower extracellular Cl- levels. Extensive preclinical and clinical evidence indicates that alterations in GABAergic inhibition caused by drugs, toxins, gene defects or other disease states (including seizures themselves) play a causative or contributing role in facilitating or maintaning seizure activity. Conversely, enhancement of GABAergic transmission through pharmacological modulation of the GABA system is a major mechanism by which different antiseizure medications exert their therapeutic effect. In this article, we review the pharmacology and function of the GABA system and its perturbation in seizure disorders, and highlight how improved understanding of this system offers opportunities to develop more efficacious and better tolerated antiseizure medications. We also review the available data for the two most recently approved antiseizure medications that act, at least in part, through GABAergic mechanisms, namely cenobamate and ganaxolone. Differences in the mode of drug discovery, pharmacological profile, pharmacokinetic properties, drug-drug interaction potential, and clinical efficacy and tolerability of these agents are discussed.

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.

Value contribution of cenobamate for the treatment of Focal-Onset Seizures (FOS) in patients with drug-resistant epilepsy (DRE) in Spain through reflective Multi-Criteria Decision Analysis (MCDA)

INTRODUCTION

Epilepsy is one of the most common neurological conditions worldwide. The main goal of its treatment is to achieve seizure freedom without intolerable adverse effects. However, despite the availability of many anti-seizure medications, including the latest options, called third-generation anti-seizure medications (ASMs), approximately 40% of people with epilepsy present drug-resistant epilepsy (DRE). Cenobamate is the first ASM approved in Spain for the adjunctive treatment of Focal-Onset Seizures (FOS) in adult patients with DRE. In a chronic disease with a portfolio of available ASMs, the decision to introduce a new therapeutic alternative must follow a holistic evaluation of value provided. Reflective Multi-Criteria Decision Analysis (MCDA) methodology allows to determine the value contribution of a treatment in a given indication considering all relevant criteria for healthcare decision-making in a transparent and systematic manner from the perspective of relevant stakeholders.

PURPOSE

The aim of this study was to determine the relative value contribution of cenobamate in the treatment of FOS in patients with DRE compared with third-generation ASMs using reflective MCDA-based methodology.

METHODS

A systematic literature review (combining biomedical databases and grey literature sources) was performed to populate the Evidence and Value: Impact on DEcisionMaking (EVIDEM) MCDA framework adapted to determine what represents value in the management of FOS in patients with DRE in Spain. The study was conducted in two phases. The first took place in 2021 with a multi-stakeholder group of eight participants. The second phase was conducted in 2022 with a multi-stakeholder group of 32 participants. Participants were trained in MCDA methodology and scored four evidence matrices (cenobamate vs. brivaracetam, vs. perampanel, vs. lacosamide and vs. eslicarbazepine acetate). Results were analyzed and discussed in a group meeting through reflective MCDA discussion methodology.

RESULTS

DRE is considered a very severe condition associated with many important unmet needs, mainly with regard to the lack of more effective treatments to achieve the ultimate goal of treatment. Compared to third-generation ASMs, cenobamate is perceived to have a better efficacy profile based on improvements in responder rate and seizure freedom. Regarding safety, it is considered to have a similar profile to alternatives and a positive quality-of-life profile. Cenobamate results in lower direct medical costs (excluding pharmacological) and indirect costs. Overall, cenobamate is regarded as providing a high therapeutic impact and supported by high-quality evidence.

CONCLUSIONS

Based on reflective MCDA methodology and stakeholders' experience in clinical management of epilepsy in Spain, cenobamate is perceived as a value-added option for the treatment of patients with DRE when compared with third-generation ASMs.