EEG parameters as endpoints in epilepsy clinical trials - An expert panel opinion paper.

INTRODUCTION: The lack of ideal measurement of treatment efficacy is a well acknowledged problem in the epilepsy community, both in clinical care and clinical trials. Whilst still the current gold-standard, self-reported seizure frequency significantly underestimates the true number of seizures and does not account for any other at least equally important outcome parameters, such as neurodevelopment and cognition. With the rise of disease modifying treatments, the need for more reliable endpoints in practice and clinical trials becomes more pressing. In this paper we assembled an expert panel to discuss the nature of these needs, current limitations, and obstacles based on a survey amongst these experts who were queried about the most important issues regarding the use of electroencephalography (EEG) parameters as endpoints in clinical drug and device development. METHODS: A structured survey was sent to a group of experts in the design and conduct of epilepsy trials in adults and children. This was followed by a virtual in-person meeting discussing the results of the trial and identifying a list of most important issues. RESULTS: Six clinical trialists and 5 individuals from pharmaceutical companies returned the survey containing 14 questions, and 8 clinical trialists and 10 pharma-representatives attended the meeting. Three main issues were identified (1) lack of accuracy of seizure diaries due to nocturnal seizures, subtle motor seizures, impairment of consciousness and lack of awareness of the seizure by the patient (2) inter-rater variability of EEG assessment (3) lack of standardization regarding definition(s) of seizures (clinical and electrographic), EEG recording methods and EEG data management. Recommended solutions included (1) validation of EEG parameters as biomarkers and use of wearables (2) development of a manual that describes EEG rating criteria, protocol for validation by > 1 central reader and use of a resolution of disagreements reporting template (3) standardization of EEG recording, data management and reporting. DISCUSSION & CONCLUSION: Current developments in research and technology seem promising to advance the use of EEG parameters as potential endpoints and offer partial solutions to the current needs. However, continuous, focused and collaborative efforts of all stakeholders (academia, industry and regulatory agencies) are needed to formulate guidelines, validate emerging technologies and approve them for use in trials. It is the intent of this opinion "position paper" to stimulate those efforts.

A Review of the New Antiepileptic Drugs for Focal-Onset Seizures in Pediatrics: Role of Extrapolation.

Most antiepileptic drugs (AEDs) receive regulatory approval for children years after the drug is available in adults, encouraging off-label use of the drug in children and hindering attempts to obtain quality pediatric data in controlled trials. Extrapolating adult efficacy data to pediatrics can reduce the time between approval in adults and that in children. To extrapolate efficacy from adults to children, several assumptions must be supported, such as (1) a similar disease progression and response to interventions in adults and children, and (2) similar exposure response in adults and children. The Pediatric Epilepsy Academic Consortium for Extrapolation (PEACE) addressed these assumptions in focal-onset seizures (FOS), the most common seizure type in both adults and children. PEACE reviewed the biological and clinical evidence that supported the assumptions that children with FOS have a similar disease progression and response to intervention as adults with FOS. After age 2 years, the pathophysiological underpinnings of FOS and the biological milieu in which seizures are initiated and propagated in children, seizure semiology, electroencephalographic features, etiology and AED response to FOS in children are similar to those in adults with FOS. PEACE concluded that extrapolation of efficacy data in adults to pediatrics in FOS is supported by strong scientific and clinical evidence. However, safety and pharmacokinetic (PK) data cannot be extrapolated from adults to children. Based on extrapolation, eslicarbazepine is now approved for children with FOS, down to age 4 years. Perampanel, lacosamide and brivaracetam are now undergoing PK and safety studies for the purposes of extrapolation down to age 2 or 4 years. When done in conjunction with PK and safety investigations in children, extrapolation of adult data from adults to children can reduce the time delay between approval of effective and safe AEDs in adults and approval in children.

Extrapolating evidence of antiepileptic drug efficacy in adults to children ≥2 years of age with focal seizures: The case for disease similarity.

Expediting pediatric access to new antiseizure drugs is particularly compelling, because epileptic seizures are the most common serious neurological symptom in children. Analysis of antiepileptic drug (AED) efficacy outcomes of randomized controlled trials, conducted during the past 20 years in different populations and a broad range of study sites and countries, has shown considerable consistency for each drug between adult and pediatric populations. Historically, the majority of regulatory approvals for AEDs have been for seizure types and not for specific epilepsy syndromes. Available data, both anatomical and neurophysiological, support a similar pathophysiology of focal seizures in adults and young children, and suggest that by age 2 years the structural and physiological milieu upon which seizures develop is similar. Although the distribution of specific etiologies and epilepsy syndromes is different in children from in adults, this should not impact approvals of efficacy based on seizure type, because the pathophysiology of focal seizures and the drug responsiveness of these seizure types are quite similar. Safety and pharmacokinetics cannot be extrapolated from adults to children. The scientific rationale, clinical consensus, and published data support a future approach accepting efficacy data from adult trials and focusing exclusively on prospective pharmacokinetic, tolerability, and safety studies and long-term follow-up in children. Whereas tolerability studies can be compared easily in children and adults, safety studies require large numbers of patients followed for many years.

On Quantitative Biomarkers of VNS Therapy Using EEG and ECG Signals.

OBJECTIVE: The goal of this work is to objectively evaluate the effectiveness of neuromodulation therapies, specifically, Vagus nerve stimulation (VNS) in reducing the severity of seizures in patients with medically refractory epilepsy. METHODS: Using novel quantitative features obtained from combination of electroencephalographic (EEG) and electrocardiographic (ECG) signals around seizure events in 16 patients who underwent implantation of closed-loop VNS therapy system, namely AspireSR, we evaluated if automated delivery of VNS at the time of seizure onset reduces the severity of seizures by reducing EEG spatial synchronization as well as the duration and magnitude of heart rate increase. Unsupervised classification was subsequently applied to test the discriminative ability and validity of these features to measure responsiveness to VNS therapy. RESULTS: Results of application of this methodology to compare 105 pre-VNS treatment and 107 post-VNS treatment seizures revealed that seizures that were acutely stimulated using VNS had a reduced ictal spread as well as reduced impact on cardiovascular function compared to the ones that occurred prior to any treatment. Furthermore, application of an unsupervised fuzzy-c-mean classifier to evaluate the ability of the combined EEG-ECG based features to classify pre and post-treatment seizures achieved a classification accuracy of 85.85%. CONCLUSION: These results indicate the importance of timely delivery of VNS to reduce seizure severity and thus help achieve better seizure control for patients with epilepsy. SIGNIFICANCE: The proposed set of quantitative features could be used as potential biomarkers for predicting long-term response to VNS therapy.

Outcome-centered antiepileptic therapy: Rate, rhythm and relief.: Implementing AAN Epilepsy Quality Measures in clinical practice.

Clinicians who manage patients with epilepsy are expected to assess the relevance of clinical trial results to their practice, integrate new treatments into the care algorithm, and implement epilepsy quality measures, with the overall goal of improving patient outcomes. A disease-based clinical framework that helps with choice and combinations of interventions facilitates provision of efficient, cost-effective, and high-quality care. This article addresses the current conceptual framework that informs clinical evaluation of epilepsy, explores gaps between development of treatment options, quality measures and clinical goals, and proposes an outcome-centered approach that bridges these gaps with the aim of improving patient and population-level clinical outcomes in epilepsy.

Assessment of the effects of lacosamide on sleep parameters in healthy subjects.

PURPOSE: Seizures and antiepileptic drugs (AED) may disrupt sleep patterns in patients with epilepsy, thus evaluation of lacosamide effects on objective and subjective sleep measures is warranted. METHODS: A multicenter, interventional, open-label study (NCT01530386) was conducted in healthy subjects without confounding effects of concomitant AED use, co-morbidities, or disease state to determine whether lacosamide impacts sleep parameters after 22 days of lacosamide exposure. After overnight polysomnography (PSG) to assess baseline parameters, lacosamide was initiated at 100mg/day (50mg twice daily) and increased by 100mg/day weekly to 300 mg/day (the mid-range maintenance dose for adjunctive therapy). The primary variable was change from baseline to post-treatment in wake after sleep onset (WASO). Secondary variables included additional objective sleep measures, subject-reported measures of sleep quality, daytime sleepiness, and tolerability. Change from baseline in WASO was analyzed using the Wilcoxon rank-sum test. RESULTS: A total of 27 subjects received ≥1 dose of lacosamide and 25 subjects completed the study. For WASO, median change from baseline was a 6-min reduction (95% confidence interval: -38, 77.5; p=0.1074) after lacosamide treatment; this was considered not clinically relevant. No clinically relevant changes were observed in any secondary variables. Thirteen subjects (48%) reported a treatment-emergent adverse event, none of which was severe or led to study discontinuation. CONCLUSION: Lacosamide 300 mg/day had no effect on objective or subjective sleep parameters in healthy subjects and was generally well tolerated.

Conversion to lacosamide monotherapy in the treatment of focal epilepsy: results from a historical-controlled, multicenter, double-blind study.

OBJECTIVE: To evaluate the efficacy and safety of conversion to lacosamide 400 mg/day monotherapy in adults with focal epilepsy. METHODS: This historical-controlled, double-blind study (NCT00520741) enrolled patients aged 16-70 years on stable doses of 1-2 antiepileptic drugs (AEDs) and experiencing 2-40 partial-onset seizures per 28 days during the 8-week prospective Baseline. Patients were randomized to lacosamide 400 or 300 mg/day (3:1 ratio), starting at 200 mg/day and titrated over 3 weeks to randomized dose. Patients then withdrew background AEDs over 6 weeks and entered a 10-week Monotherapy Phase. The primary assessment was the Kaplan-Meier-predicted percentage of patients on 400 mg/day in the full analysis set (FAS) meeting ≥ 1 predefined seizure-related exit criterion by day 112, compared with the historical-control threshold (65.3%). RESULTS: Four hundred twenty-five patients were enrolled and were eligible for safety analyses (400 mg/day, n = 319; 300 mg/day, n = 106). A total of 271 (63.8%) of 425 patients completed the Lacosamide Maintenance Phase (combined AED Withdrawal and Monotherapy Phases). Among 284 patients in the 400 mg/day group in the FAS, 82 (28.9%) met ≥ 1 exit criterion; the Kaplan-Meier-predicted exit percentage at day 112 for 400 mg/day (30.0%; 95% confidence interval [CI] 24.6-35.5%) was lower than the historical control. When exit events, withdrawal due to treatment-emergent adverse events (TEAEs), and withdrawal due to lack of efficacy were summed (n = 90), the predicted exit percentage (32.3%; 95% CI 26.8-37.8%) was also lower than the historical control. Most patients receiving 400 mg/day reported some improvement on the Clinical Global Impression of Change (75.4%) and Patient Global Impression of Change (74.3%). Overall, the most common (>10%) TEAEs were dizziness (24.0%), headache (14.4%), nausea (13.4%), convulsion (11.5%), somnolence (10.4%), and fatigue (10.1%); most (74.1%) were mild-to-moderate in intensity. Seventy-two patients (16.9%) discontinued due to TEAEs. Seventeen patients (4%, all receiving 400 mg/day) experienced serious AEs. SIGNIFICANCE: Lacosamide 400 mg/day monotherapy was effective, with a favorable safety profile in patients with focal epilepsy.

Importance and hurdles to drug discovery for neurological disease.

This is a critical time in neurotherapeutics. The prevalence of neurological disease, such as dementia, stroke, and peripheral neuropathy, is large and growing consequent to the aging population. The personal and societal impact of these disorders is enormous, and the number of novel therapies in the pipeline for these disorders has been contracting. Support for the development of neurotherapies must continue from the bench to their ultimate place at the bedside. Academic medicine must continue to play a critical role, in league with industry and government, in the development of novel neurotherapies desperately needed by an ever-expanding population. Critical steps include the identification and adoption of reliable, valid, and reproducible biomarkers to serve as primary endpoints in clinical trials of neurological disease.

Efficacy of antiepileptic drugs in adults predicts efficacy in children: a systematic review.

OBJECTIVE: Due to the challenges inherent in performing clinical trials in children, a systematic review of published clinical trials was performed to determine whether the efficacy of antiepileptic drugs (AEDs) in adults can be used to predict the efficacy of AEDs in the pediatric population. METHODS: Medline/PubMed, EMBASE, and Cochrane library searches (1970-January 2010) were conducted for clinical trials of partial-onset seizures (POS) and primary generalized tonic-clonic seizures (PGTCS) in adults and in children <2 and 2-18 years. Independent epidemiologists used standardized search and study evaluation criteria to select eligible trials. Forest plots were used to investigate the relative strength of placebo-subtracted effect measures. RESULTS: Among 30 adjunctive therapy POS trials in adults and children (2-18 years) that met evaluation criteria, effect measures were consistent between adults and children for gabapentin, lamotrigine, levetiracetam, oxcarbazepine, and topiramate. Placebo-subtracted median percent seizure reduction between baseline and treatment periods (ranging from 7.0% to 58.6% in adults and from 10.5% to 31.2% in children) was significant for 40/46 and 6/6 of the treatment groups studied. The ≥50% responder rate (ranging from 2.0% to 43.0% in adults and from 3.0% to 26.0% in children) was significant for 37/43 and 5/8 treatment groups. In children <2 years, an insufficient number of trials were eligible for analysis. CONCLUSIONS: This systematic review supports the extrapolation of efficacy results in adults to predict a similar adjunctive treatment response in 2- to 18-year-old children with POS.

Sleep-disordered breathing in Beckwith-Wiedemann syndrome: three patients.

Beckwith-Wiedemann syndrome is associated with craniofacial abnormalities that may predispose patients to sleep-related breathing disorders. There is limited literature on the polysomnography findings for children with this syndrome. Three patients with Beckwith-Wiedemann syndrome underwent polysomnography in our sleep lab and were found to have a variety of sleep-disordered breathing that ranged from obstructive apnea to isolated REM sleep-related hypoxemia-hypoventilation without obstructive apnea. Suspicion for sleep-disordered breathing should be high in children with Beckwith-Wiedemann syndrome.

Sleep and epilepsy.

The relationship of sleep and epilepsy demonstrates the delicate association of brain physiology and dysfunction. Sleep affects the distribution and frequency of epileptiform discharges in humans and influences the rate of kindling in animals. Epileptic discharges, on the other hand, alter sleep regulation and provoke sleep disruption. This effect on sleep appears to carry over to sleep complaints in patients with epilepsy. Individuals with epilepsy frequently complain of symptoms suggestive of disturbed sleep, such as excessive daytime sleepiness, insomnia, or with more subtle complaints such as an increase in seizure frequency. More commonly, these symptoms indicate an underlying sleep disorder rather than the effect of epilepsy or medication on sleep. Clinicians must be able to identify and differentiate between potential sleep disorders and sleep dysfunction related to epilepsy and direct therapy to improve the patient's symptoms. The reciprocal relationship of sleep and epilepsy and the management of sleep complaints in the patient with epilepsy will be reviewed.

Feasibility and acceptance of salivary monitoring of antiepileptic drugs via the US Postal Service.

Salivary and serum levels of phenobarbital, carbamazepine, and phenytoin are closely correlated. Salivary monitoring of antiepileptic drugs has a number of advantages including the potential for home collection if measured levels are unaffected by transit in the mail. Saliva was collected from 60 adult and 42 pediatric patients in the clinic. A control aliquot was immediately frozen, and a second aliquot was packaged and mailed to the laboratory. Patients were also asked to collect another sample at the same time on the following day and mail it to the laboratory. On receipt, all samples were held frozen and analyzed as a single batch by fluorescence polarization immunoassay. The effects of mailing, the duration in transit, and the season were assessed by multivariable, repeated-measures analysis of variance. One hundred two saliva samples were collected in a mean of 2.6 minutes, and the mailed aliquot was received in a mean of 6.4 days. Two children and 3 adults (4.9% of total) preferred blood collection, but the rest preferred saliva collection or had no preference. There was no significant difference between the control sample and the clinic mailed samples for any of the 3 medications. There were no significant effects of the duration in transit or the season on reliability. Transit of saliva samples in the mail does not adversely affect accuracy of antiepileptic drug measurement. Patients prefer and can successful collect saliva samples at home. Home monitoring of salivary antiepileptic drug levels is a cost-effective technique that deserves additional study.

Heart rate variability during interictal epileptiform discharges.

RATIONALE: Seizures may produce a variety of autonomic alterations. These alterations may occur due to evoked autonomic reflexes or as a direct cortical effect on autonomic control. In animal studies, lock step phenomena of interictal discharges to autonomic output have been repeatedly documented. However, the association of interictal discharges and autonomic output is not as well established in humans. METHODS: RR intervals timely locked to interictal epileptiform discharge (RR(n)) were compared to RR intervals immediately following (RR(n+1)) interictal discharges in 40 patients with focal onset epilepsy and low baseline heart beat variability. RESULTS: In 20 patients with 200 left sided interictal epileptiform discharges, RR(n) shortened in 100 and prolonged in 31 when compared to RR(n+1) intervals. While in 20 patients with 200 right sided interictal epileptiform discharges RR(n) intervals shortened in 17 and prolonged in 116 (Chi square P<0.001). No consistent differences in RR(n) intervals variability between frontal versus temporal localization of the interictal discharges from the same side was found. CONCLUSIONS: Interictal discharges, may influence autonomic control over the cardiac cycle and agree with animal studies. Further study of the relationship of interictal discharges to autonomic output is needed to delineate the potential lateralized influences over autonomic nervous system.

Obstructive sleep apnea in epilepsy.

Obstructive sleep apnea can affect an individual with epilepsy profoundly. These relatively common disorders can coexist and potentially exacerbate each other. The identification and appropriate treatment of OSA may have far-reaching consequences in improving a patient's quality of life and recurrence of seizures. Clinicians must be aware of the relationship of these disorders and keenly question epilepsy patients, regardless of their body habitus, regarding potential symptoms of sleep apnea. Although the underlying pathogenic mechanisms are unclear, we can model the information gained from the observations to further the understanding of the relationship between sleep and epilepsy.

Cluster headaches simulating parasomnias.

Nocturnal episodes of agitated arousal in otherwise healthy young children are often related to nonrapid eye movement parasomnias (night terrors). However, in patients with acute onset or increased frequency of parasomnias, organic causes of discomfort must be excluded. We report four young children whose parasomnias were caused by nocturnal cluster headaches and who responded to indomethacin dramatically.