Practical Use of Newer Antiepileptic Drugs as Adjunctive Therapy in Focal Epilepsy

Pharmacological treatment for older adults with epilepsy and comorbid neurodegenerative disorders

PURPOSE OF REVIEW

An increased interest in epilepsy in older adults has emerged as the global population ages. The purpose of this article is to review the literature regarding the pharmacological treatment of epilepsy in older adults, highlighting issues specifically pertinent to those living with comorbid neurodegenerative disorders.

RECENT FINDINGS

Although new original research remains sparse, in the last 5 years, there has been a growing number of studies addressing the relationship between epilepsy and neurodegenerative disorders. Accurate diagnosis is incredibly challenging with electroencephalogram findings often requiring circumspect interpretation. Older individuals are often excluded from or under-represented in clinical trials, and there are sparse guidelines offered on the management of these patients, with even less available in reference to those with neurodegenerative comorbidities.

SUMMARY

We propose that seizures occurring earlier in the neurodegenerative process should be treated aggressively, with the goal to inhibit neuro-excitotoxicity and the associated neuronal loss. By strategically choosing newer antiseizure medications with less adverse effects and a holistic approach to treatment, a patient's time living independently can be conserved. In addition, we advocate for original, multinational collaborative research efforts.

The economic burden of newly diagnosed epilepsy in Spain

OBJECTIVE

The aim of this study was to determine the hospital burden and economic impact of epilepsy in adults in Spain and identify characteristics associated with higher direct medical costs.

METHOD

Patients newly diagnosed with epilepsy at the outpatient epilepsy unit of a tertiary hospital in Spain in 2012 were included. Sociodemographic and clinical data and use of health resources were collected retrospectively from electronic medical records from the time of diagnosis to the end of follow-up (2019). Direct costs (in 2012 Euro) were estimated and linear regression models built to explore predictors of higher costs.

RESULTS

We studied 110 patients with newly diagnosed epilepsy. Their mean (SD) age was 52.6 (19.6) years and 53.6% were men. Eighty-nine patients (80.9%) had focal epilepsy and 45 (40.9%) had an unknown etiology. At 6 months, 79.1% of patients were classified as responders and 17.6% as having drug-resistant epilepsy. The mean direct cost in the first year of epilepsy diagnosis was €3816.06, 49.7% of which was due to hospital admissions. The mean annual cost per patient was €2584.17, 51.4% of which was due to anti-seizure medications (ASMs). Focal epilepsy and poor response in the first 6 months of treatment predicted higher annual costs, while focal epilepsy and pre-existing comorbidities predicted higher costs in the first year.

CONCLUSIONS

The direct cost of newly diagnosed epilepsy in adults in our area is €2584 per patient/year. Anti-seizure medication use is the main cost driver. Focal epilepsy, comorbidities, and poor response to ASMs are independent predictors of higher costs.

Drug treatment of epilepsy: From serendipitous discovery to evolutionary mechanisms

Epilepsy is a chronic brain disorder caused by abnormal firing of neurons. Up to now, using antiepileptic drugs is the main method of epilepsy treatment. The development of antiepileptic drugs lasted for centuries. In general, most agents entering clinical practice act on the balance mechanisms of brain "excitability-inhibition". More specifically, they target voltage-gated ion channels, GABAergic transmission and glutamatergic transmission. In recent years, some novel drugs representing new mechanisms of action have been discovered. Although there are about 30 available drugs in the market, it is still in urgent need of discovering more effective and safer drugs. The development of new antiepileptic drugs is into a new era: from serendipitous discovery to evolutionary mechanism-based design. This article presents an overview of drug treatment of epilepsy, including a series of traditional and novel drugs.

Neurodegenerative pathways as targets for acquired epilepsy therapy development

There is a growing body of clinical and experimental evidence that neurodegenerative diseases and epileptogenesis after an acquired brain insult may share common etiological mechanisms. Acquired epilepsy commonly develops as a comorbid condition in patients with neurodegenerative diseases such as Alzheimer's disease, although it is likely much under diagnosed in practice. Progressive neurodegeneration has also been described after traumatic brain injury, stroke, and other forms of brain insults. Moreover, recent evidence has shown that acquired epilepsy is often a progressive disorder that is associated with the development of drug resistance, cognitive decline, and worsening of other neuropsychiatric comorbidities. Therefore, new pharmacological therapies that target neurobiological pathways that underpin neurodegenerative diseases have potential to have both an anti-epileptogenic and disease-modifying effect on the seizures in patients with acquired epilepsy, and also mitigate the progressive neurocognitive and neuropsychiatric comorbidities. Here, we review the neurodegenerative pathways that are plausible targets for the development of novel therapies that could prevent the development or modify the progression of acquired epilepsy, and the supporting published experimental and clinical evidence.

Budget Impact Analysis of Brivaracetam Adjunctive Therapy for Partial-Onset Epileptic Seizures in Valencia Community, Spain

BACKGROUND AND OBJECTIVE

More than 30% of patients with epilepsy have inadequate control of seizures with drug therapy. The goal of this study is to determine the budget impact (BI) of the introduction of brivaracetam to the portfolio of approved drugs in Spain as adjunctive therapy for the treatment of partial-onset epilepsy in patients over 16 years old with a 5-year time horizon in the Valencia Community, a Spanish region with a population of 5 million.

METHODS

The BI model compares the pharmaceutical expenditure on antiepileptics in two scenarios: with and without brivaracetam. It assumes that the introduction and increased use of brivaracetam will lead to a proportional decrease in consumption of coexisting adjunctive antiepileptics and calculates the evolution of the consumption of brivaracetam over 5 years (2016-2020). The model was designed from the perspective of the Spanish National Health System. Data on the candidate population, consumption of antiepileptics, market share and pharmaceutical expenditure were obtained from real-world data. Finally, a sensitivity analysis was carried out on the set of variables involved in the evolution of costs using a Monte-Carlo simulation.

RESULTS

The model estimates that the target population eligible for adjunctive antiepileptics will hold at around 2352 between 2016 and 2020. Annual expenditure on antiepileptics is approximately €3.6 million. The number of patients eligible for treatment with brivaracetam would increase from 42 to 179 and annual savings of 0.09-0.37% would be created, representing €41,873 over 5 years (0.23% of the total budget). The sensitivity analysis corroborates that the probability of achieving savings with brivaracetam is around 84%.

CONCLUSIONS

Brivaracetam is a therapeutic alternative that allows savings for the health system in patients with non-controlled epilepsy in monotherapy, having a fixed, predictable annual cost (independent of dose) from the first day of treatment as the lack of need for titration means the patient is within a range of therapeutic doses from the first dose.

Changing the neurology policy landscape in the United States: Misconceptions and facts about epilepsy

Epilepsy has a relatively high prevalence, and diagnosis and treatment are often challenging. Seizure freedom without significant side effects is the ultimate goal for both physicians and patients, but not always achievable. In those cases, the treatment goals of patients and providers may differ. In the United States, many clinicians continue to prescribe older AEDs, even though newer AEDs have a more desirable safety and tolerability profile, fewer drug-drug interactions, and are associated with lower epilepsy-related hospital visits. Newer AEDs are more commonly prescribed by neurologists and epilepsy center physicians, highlighting the importance of access to specialty care. We report that antiepileptic drugs are not the dominant cost driver for patients with epilepsy and costs are considerably higher in patients with uncontrolled epilepsy. Poor drug adherence is considered a main cause of unsuccessful epilepsy treatment and is associated with increases in inpatient and emergency department admissions and related costs. Interventions and educational programs are needed to address the reasons for nonadherence. Coverage policies placing a higher cost burden on patients with epilepsy lead to lower treatment adherence, which can result in higher future health care spending. Epilepsy is lagging behind other neurological conditions in terms of funding and treatment innovation. Increased investment in epilepsy research may be particularly beneficial given current funding levels and the high prevalence of epilepsy.

Eslicarbazepine acetate in epilepsies with focal and secondary generalised seizures: systematic review of current evidence

INTRODUCTION

Eslicarbazepine acetate (ESL) is a third-generation antiepileptic drug (AED) approved for adjunctive treatment in adults, children, and adolescents with focal-onset seizures. Recently ESL was approved for initial monotherapy in adults. The intention of this article is to review current evidence for ESL and to summarise its pharmacological profile in comparison to other AEDs of the dibenzazepine group. Areas covered: We performed a systematic literature search in electronic databases (MEDLINE database, Cochrane Central Register of Controlled Trials, Excerpta Medica dataBASE) using a combined search strategy including the following keywords: eslicarbazepine, epilepsy and seizure. The search was performed from 2000 until December 2017. Using a standardised assessment form, information on the study design, methodological framework, data sources and efficacy and adverse events attributed to ESL were extracted from each publication and systematically reported. Expert commentary: ESL is an effective, safe and well tolerated third-generation AED for the treatment of focal epilepsies. During therapy, especially serum sodium levels and possible interactions with other substances have to be monitored. As of yet, long-term experience is still needed to make severe late-occurring adverse events unlikely and to obtain data regarding its use in pregnancy.

[Perampanel in the treatment of patients with epilepsy]

Development of new antiepileptic drugs (AED) does not stop due to the fact that the number of patients with pharmacoresistant epilepsy remains at about 30%. One of the newest AEDs is perampanel (PER), a selective, non-competitive AMPA receptor antagonist to target post-synaptic glutamate transmission. PER is approved in the Russian Federation as adjunctive treatment for focal seizures with or without secondarily generalized seizures and for primary generalized tonic-clonic (PGTC) seizures in idiopathic generalized epilepsy (IGE) in patients with epilepsy aged ≥12 years. The drug is effective and well-tolerated in the dose of 4-8 mg/day, and most side effects are dose-dependent. The high efficacy of PER combined with the good tolerability, absence of life-threatening adverse reactions and convenient intake allow us to recommend PER as the first choice additional drug in treatment of patients with epilepsy.

Pharmacological Treatment of Drug-Resistant Epilepsy in Adults: a Practical Guide

More than 30 % of adults with epilepsy do not fully control on the currently available antiepileptic drugs (AEDs). For these and many other patients, combinations of agents, often possessing different mechanisms of actions, are employed with the aim of achieving seizure freedom or the best available prognosis in terms of reduced seizure numbers and severity. This review discusses my own approach to optimising outcomes in as many of these patients as possible by adjusting the drug burden using a combination of two, three or sometimes four or more AEDs. Modes of drug action are reviewed and practical strategies for treating different patients with drug-resistant epilepsy have been explored. Only for sodium valproate with lamotrigine is there good evidence of synergism. The final part of this practical paper consists of six individual illustrative cases with appropriate comments.

Sodium Channel Blockers in the Treatment of Epilepsy

Sodium channel blockers have been the mainstay of the pharmacological management of focal and generalised tonic-clonic seizures for more than 70 years. The focus of this paper will be on phenytoin, carbamazepine, lamotrigine, oxcarbazepine, rufinamide, lacosamide and eslicarbazepine acetate. All these antiepileptic drugs have similar efficacy and share similar dose-dependent, adverse effect profiles, although phenytoin, carbamazepine and oxcarbazepine are more likely to cause idiosyncratic reactions than the others. With the exception of lamotrigine, rufinamide and lacosamide, all are enzyme inducers and most are minor teratogens; although data on teratogenicity are sparse with lacosamide and eslicarbazepine acetate. There is increasing evidence that these drugs differ mechanistically, with the newer agents, lacosamide and eslicarbazepine acetate, having their major pharmacological effect on the slow inactivation state of the sodium channel, which may be associated with better tolerability at higher dosage, although hard evidence in support of this observation is currently not available. Rufinamide is licensed only for Lennox-Gastaut syndrome in children aged 4 years and above. There is a move away from using enzyme inducers, particularly phenytoin and carbamazepine, in everyday clinical practice. There seems little doubt, however, that some sodium channel blockers will have an enduring place in the management of epilepsy well into the 21st century.

Psychiatric side effects and antiepileptic drugs: Observations from prospective audits

Psychiatric comorbidities are common in people with epilepsy. A retrospective study of characteristics associated with withdrawal due to psychiatric side effects was undertaken in patients with treated epilepsy participating in prospective audits with new antiepileptic drugs (AEDs). A total of 1058 treated patients with uncontrolled seizures (942 focal-onset seizures, 116 generalized genetic epilepsies [GGEs]) participated in eight prospective, observational audits from 1996 to 2014. These patients were prescribed adjunctive topiramate (n=170), levetiracetam (n=220), pregabalin (n=135), zonisamide (n=203), lacosamide (n=160), eslicarbazepine acetate (n=52), retigabine (n=64), or perampanel (n=54). Doses were titrated according to efficacy and tolerability to optimize zeizure outcomes and reduce side effects. Psychiatric comorbidities were recorded prior to and after the addition of each AED. At baseline, patients with focal-onset seizures (189 of 942; 20.1%) were statistically more likely to have psychiatric diagnoses compared to patients with GGEs (14 of 116, 12.1%; p=0.039). Following adjunctive AED treatment, neuropsychiatric adverse effects led to AED withdrawal in 1.9-16.7% of patients. Patients with a pre-treatment psychiatric history (22 of 209; 10.5%) were statistically more likely to discontinue their new AED due to psychiatric issues compared to patients with no previous psychiatric diagnosis (50 of 849; 5.9%; p=0.017). Patients receiving sodium channel blocking AEDs (4 of 212, 1.9%) were statistically less likely to develop intolerable psychiatric problems, compared to those on AEDs possessing other mechanisms of action (68 of 846, 8.0%; p=0.012). Depression was the commonest problem, leading to discontinuation of AEDs in 2.8% (n=30) patients. Aggression was statistically more common in men (11 of 527, 2.1%) compared to women (1 of 531, 0.2%; p=0.004). Patients with learning disability (12 of 122, 9.8%; p=0.0015) were statistically less likely to have psychiatric issues prior to adjunctive AED treatment compared to other patients (208 of 936, 22.2%), but there were no statistically significant differences once the new AEDs were added (8 of 122 patients with learning disability, 6.6%; 64 of 936 other patients, 6.8%). Awareness of these issues may assist clinicians in avoiding, identifying and treating psychiatric comorbidities in people with epilepsy.

Tolerability and Safety of Commonly Used Antiepileptic Drugs in Adolescents and Adults: A Clinician's Overview

This paper discusses the issues surrounding the tolerability and safety of the commonly used antiepileptic drugs (AEDs) in adolescents and adults. The content includes dose-related adverse effects, idiosyncratic reactions, behavioural and psychiatric comorbidities, chronic problems, enzyme induction and teratogenesis. Twenty-one AEDs are discussed in chronological order of their introduction into the UK, starting with phenobarbital and ending with brivaracetam. Wherever possible, advice is given on anticipating, recognising and managing these issues and thereby improving the lives of people with epilepsy, most of whom will need to take one or more of these agents for life. Avoidance of side effects will increase the possibility of achieving and maintaining long-term seizure freedom. Alternatively, adverse events from AEDs will substantially reduce quality of life and often result in higher healthcare costs.

Outcomes in newly diagnosed epilepsy in adolescents and adults: Insights across a generation in Scotland

The outpatient services at the Epilepsy Unit in the Western Infirmary, Glasgow, Scotland was set up in September 1982. From the outset patient data were collected prospectively. A focused approach to patients with newly diagnosed epilepsy was developed and a series of 4 analyses have been undertaken over the intervening years, with results from the latest still being written up for publication. A total of 16 published papers have described patient outcomes over the years, focusing on response to different drug schedules. A number of factors contributing to a poorer prognosis has been identified and follow up data over 30 years has confirmed the lack of overall improvement in prognosis despite the introduction of 14 new AEDs for the common epilepsies in the UK with different mechanisms of action over this time. Patterns of response have confirmed that a majority of patients will go into remission with around 25% of the population appearing to have refractory epilepsy de novo. Since all available options are antiseizure and not antiepilepsy drugs, some patients, who are initially well controlled, are seen to relapse over time and to develop refractory epilepsy. A new approach in identifying and treating epileptogenesis is necessary, if this disappointing scenario is to be reversed with the next generation of antiepileptic drugs.

[Impact of early benefit assessment on patients with epilepsy in Germany: Current healthcare provision and therapeutic needs]

Epilepsy is one of the most common chronic neurological diseases and represents a significant burden for patients, their families and society. In more than 75 % of patients anticonvulsant therapy consists of valproate, carbamazepine, lamotrigine or levetiracetam. There is a need for polytherapy in drug-refractory patients and they suffer from negative effects on quality of life and employment that is associated with high indirect costs. To allow a comprehensive treatment in this patient group, access to new anticonvulsants with novel modes of action is needed; however, all applications for new antiepileptic drugs failed to prove added benefits during the Pharmaceutical Market Restructuring Act (AMNOG) in Germany. One of the main reasons is the mandatory definition of a standard comparative therapy. It remains unclear whether there will be studies in the future which will fulfill the requirements of the current version of AMNOG. Observational studies after approval and marketing of new antiepileptic drugs could be better alternatives to prove added benefits for individual patients in the current German healthcare system.