Pregabalin adjunctive therapy for focal onset seizures in children 1 month to <4 years of age: A double-blind, placebo-controlled, video-electroencephalographic trial

Long-term efficacy, safety, and tolerability, including behavior and executive functioning, during adjunctive lacosamide treatment in pediatric patients with uncontrolled epilepsy

OBJECTIVES

To evaluate long-term efficacy, safety, and tolerability, including behavior and executive functioning, during adjunctive lacosamide (LCM) treatment in pediatric patients (≥1 month to <18 years of age) with focal-onset or generalized seizures enrolled in 2 open-label, long-term follow-up trials.

METHODS

Two open-label extension trials (SP848: NCT00938912; EP0034: NCT01964560) were conducted in pediatric patients who had participated in previous trials of adjunctive LCM (SP0847/NCT00938431; SP0966/NCT01969851; EP0060/NCT02710890; SP0967/NCT02477839; SP0969/NCT01921205); SP848 also directly enrolled eligible pediatric patients who had not previously participated in a clinical trial of LCM. Outcomes included retention, efficacy, and safety/tolerability. Patient improvement was assessed with Clinician's and Caregiver's Global Impression of Change scale. Behavior and emotional function was assessed with Achenbach Child Behavior Checklist (CBCL) and executive functioning was assessed with Behavior Rating Inventory of Executive Function® (BRIEF).

RESULTS

The pooled dataset from both trials included 905 patients (851 in the focal-onset seizure population and 47 in the generalized seizure population). In the overall population, Kaplan-Meier-estimated 1-year retention was 80 %. From baseline to the end of the treatment period, patients in the focal-onset seizure population had a median percent reduction in focal-onset seizure frequency per 28 days of 60.4 %, 55.4 % of patients were 50 % responders, and 40.8 % of patients were 75 % responders. In patients with ≥12 months of LCM treatment, ≥12 month seizure freedom during the LCM treatment period was achieved by 29.9 % of patients in the focal-onset seizure population (median duration of first ≥12-month seizure-free interval: 641 days) and 24.4 % of patients in the generalized seizure population (median duration of first ≥12-month seizure-free interval: 665 days). Improvement during LCM treatment was reported in >75 % of patients by both physicians and caregivers. Treatment-emergent adverse events (TEAEs) were reported by 749 (82.8 %) patients, most commonly pyrexia (18.9 %), upper respiratory tract infection (18.6 %), nasopharyngitis (16.2 %), vomiting (15.7 %), and somnolence (11.8 %). The most common drug-related TEAEs were somnolence (8.5 %), dizziness (7.6 %), and vomiting (5.4 %). Behavioral and emotional function was generally stable in patients 1.5-5 years of age and slightly improved in patients ≥6 years of age, and executive functioning was stable in patients <5 years of age and generally slightly improved in patients 5-18 years of age.

CONCLUSIONS

In this analysis of a large patient pool from 2 open-label trials, long-term adjunctive LCM was efficacious and generally well tolerated in children with epilepsy and focal-onset or generalized seizures. Behavior and executive functioning were generally stable without observable worsening during long-term adjunctive LCM treatment.

Efficacy and tolerability of adjunctive lacosamide in patients aged <4 years with focal seizures

OBJECTIVE

Primary objective was to evaluate efficacy of lacosamide administered concomitantly with 1-3 antiseizure medications in young children with uncontrolled focal (partial-onset) seizures.

METHODS

Double-blind, parallel-group trial (SP0967: NCT02477839/2013-000717-20) conducted between June 2015 and May 2020 at hospitals and clinics in 25 countries. Patients (aged ≥1 month to <4 years) with uncontrolled focal seizures were randomized 1:1 to adjunctive lacosamide or placebo using an interactive voice/web response system and stratified by age. After a 20-day titration period, patients who reached target-dose range (8-12 mg/kg/day) entered a 7-day maintenance period. Region-specific primary efficacy variables were based on ≤72-h video-electroencephalograms: change in average daily frequency (ADF) of electrographic focal seizures as measured on end-of-maintenance video-electroencephalogram versus end-of-baseline video-electroencephalogram (United States); 50% responder rate (≥50% reduction in ADF of focal seizures) during maintenance (European Union).

RESULTS

In total, 255 patients were randomized (lacosamide/placebo: 128/127) and received ≥1 trial medication dose. Percentage reduction in ADF of focal seizures for lacosamide (116 patients) versus placebo (120 patients) was 3.2% (95% confidence interval = -13.6 to 17.5, p = 0.69). 50% responder rate was 41.4% for lacosamide (116 patients), 37.5% for placebo (120 patients) (p = 0.58). Treatment-emergent adverse events were reported by 44.5% of lacosamide-treated patients (placebo 51.2%).

INTERPRETATION

Adjunctive lacosamide did not show superior efficacy versus placebo in young children with focal seizures. However, efficacy variables were potentially affected by high variability and low reliability between readers in video-electroencephalogram interpretation. Lacosamide was generally well tolerated; safety profile was acceptable and consistent with that in adults and children aged ≥4 years.

Pitfalls of using video-EEG for a trial endpoint in children aged <4 years with focal seizures

OBJECTIVE

Double-blind, randomized, and placebo-controlled trial SP0967 (NCT02477839/2013-000717-20) did not demonstrate superior efficacy of lacosamide versus placebo in patients aged ≥1 month to <4 years with uncontrolled focal seizures, per ≤72 h video-electroencephalogram (video-EEG)-based primary endpoints (reduction in average daily frequency of focal seizures at end-of-maintenance [EOM] versus end-of-baseline [EOB], patients with ≥50% response). This was unexpected because randomized controlled trial SP0969 (NCT01921205) showed efficacy of lacosamide in patients aged ≥4 to <17 years with uncontrolled focal seizures. SP0969's primary endpoint was based on seizure diary instead of video-EEG, an issue with the latter being inter-reader variability. We evaluated inter-reader agreement in video-EEG interpretation in SP0967, which to our knowledge, are the first such data for very young children with focal seizures from a placebo-controlled trial.

METHODS

Local investigator and central reader agreement in video-EEG interpretation was analyzed post hoc.

RESULTS

Analysis included 105 EOB and 98 EOM video-EEGs. Local investigators and central reader showed poor agreement based on ≥2 focal seizures at EOB (Kappa = 0.01), and fair agreement based on ≥2 focal seizures at EOM (Kappa = 0.23). Local investigator and central reader seizure count interpretations varied substantially, particularly for focal seizures, but also primary generalized and unclassified epileptic seizures, at both timepoints.

INTERPRETATION

High inter-reader variability and low inter-reader reliability of the interpretation of seizure types and counts prevent confident conclusion regarding the lack of efficacy of lacosamide in this population. We recommend studies in very young children do not employ video-EEGs exclusively for accurate study inclusion or as an efficacy measure.

Long-term safety and efficacy of adjunctive brivaracetam in pediatric patients with epilepsy: An open-label, follow-up trial

OBJECTIVE

This study was undertaken to evaluate the long-term safety, tolerability, and efficacy of adjunctive brivaracetam (BRV) treatment in pediatric patients with epilepsy.

METHODS

A phase 3, open-label, multicenter, long-term follow-up trial (N01266; NCT01364597) was conducted on patients (aged 1 month to <17 years at core trial entry; direct enrollers aged 4 to <17 years) treated with BRV. Outcomes included treatment-emergent adverse events (TEAEs), behavior assessments (Achenbach Child Behavior Checklist [CBCL], Behavior Rating Inventory of Executive Function [BRIEF]/BRIEF-Preschool version [BRIEF-P]), and efficacy outcomes (percent change in focal seizure frequency, 50% responder rate for all seizure types for patient subgroups <2 years and ≥2 years of age using daily record card data).

RESULTS

Of 257 patients with ≥1 dose of BRV (141 [54.9%] male; mean age = 8.0 years [SD = 4.5]), 36 patients were <2 years of age, and 72.0% of patients had a history of focal seizures. Mean BRV exposure was 3.2 patient-years. At least one TEAE occurred in 93.4% patients, and 32.3% had serious TEAEs. Seven patients died during the trial; no deaths were considered treatment-related. Patients ≥2 years of age had a median decrease in 28-day adjusted focal seizure frequency of 62.9%, and 50.9% had a ≥50% response in all seizures. Patients <2 years of age had a median decrease in 28-day adjusted focal seizure frequency of 96.9%, and 68.2% had a ≥50% response in all seizures. Kaplan-Meier estimated treatment retention was 72.7%, 64.5%, 57.8%, 53.3%, 50.1%, and 44.8% at 1, 2, 3, 4, 5, and 6 years, respectively. Mean changes (baseline to last evaluation) for all Achenbach CBCL and BRIEF-P/BRIEF subscale scores were negative, reflecting stability/slight improvement.

SIGNIFICANCE

Long-term adjunctive BRV treatment was generally well tolerated and efficacious in reducing seizure frequency, and had high retention rates, with generally stable cognitive/behavioral scores in pediatric patients with epilepsy.

Considerations for determining the efficacy of new antiseizure medications in children age 1 month to younger than 2 years

OBJECTIVES

Drug treatment for children with epilepsy should, ideally, be governed by evidence from adequate and well-controlled clinical studies. However, these studies are difficult to conduct, and so direct evidence supporting the informed use of specific drugs is often lacking. The Research Roundtable for Epilepsy (RRE) met in 2020 to align on an approach to therapy development for focal seizures in children age 1 month <2 years of age.

METHODS

The RRE reviewed the regulatory landscape, epidemiology, seizure semiology, antiseizure medicine pharmacology, and safety issues applicable to this population.

RESULTS

After reviewing evidence, the conclusion was that pediatric efficacy trials would be impracticable to conduct but a waiver of the regulatory requirement to conduct any study would lead to an absence of information to guide dosing in a critical population. Review of available data and discussion of RRE attendees led to the conclusion that the requirements for extrapolation of efficacy from older children down to infants from age 1 month to <2 years old appeared to be met. After the RRE, the US Food and Drug Administration (FDA) approved brivaracetam for use in children with focal epilepsy above the age of 1 month in August 2021 and lacosamide in October 2021, both based on the principle of extrapolation from data in older children.

SIGNIFICANCE

These recommendations should result in more rapid accessibility of antiseizure medications for infants.

Impact of Antiseizure Medications on Appetite and Weight in Children

There are numerous potential factors that may affect growth in children with epilepsy, and these must be evaluated in any child with appetite and weight concerns. Antiseizure medications (ASMs) have potential adverse effects, and many may affect appetite, thus impacting normal growth and weight gain. The aim of this review is to focus on the impact of both epilepsy and ASMs on appetite and weight in children. We systematically reviewed studies using Medline assessing the impact of ASMs on appetite and weight in children. Eligible studies included randomized controlled trials and open-label studies (open-label extension and interventional) that targeted or included the pediatric population (0-18 years of age). Each study was classified using the American Academy of Neurology (AAN) Classification of Evidence for Therapeutic Studies, and the level of evidence for impact on appetite and weight in children was graded. ASMs associated with decreased appetite and/or weight loss include fenfluramine, topiramate, zonisamide, felbamate, rufinamide, stiripentol, cannabidiol, brivaracetam and ethosuximide; ASMs with minimal impact on weight and appetite in children include oxcarbazepine, eslicarbazepine, lamotrigine, levetiracetam, lacosamide, carbamazepine, vigabatrin and clobazam. The ASM most robustly associated with increased appetite and/or weight gain is valproic acid; however, both pregabalin and perampanel may also lead to modest weight gain or increased appetite in children. Certain ASMs may impact both appetite and weight, which may lead to increased morbidity of the underlying disease and impaired adherence to the treatment regimen.

Pregabalin add-on for drug-resistant focal epilepsy

BACKGROUND

This is an updated version of the Cochrane Review last published in Issue 7, 2019; it includes two additional studies. Epilepsy is a common neurological disease that affects approximately 1% of the UK population. Approximately one-third of these people continue to have seizures despite drug treatment. Pregabalin is one of the newer antiepileptic drugs that has been developed to improve outcomes. In this review we summarised the current evidence regarding pregabalin when used as an add-on treatment for drug-resistant focal epilepsy.

OBJECTIVES

To assess the efficacy and tolerability of pregabalin when used as an add-on treatment for drug-resistant focal epilepsy.

SEARCH METHODS

For the latest update we searched the following databases on 16 November 2020: Cochrane Register of Studies (CRS Web), and MEDLINE (Ovid, 1946 to 16 November 2020). CRS Web includes randomised or quasi-randomised, controlled trials from PubMed, Embase, ClinicalTrials.gov, the World Health Organisation International Clinical Trials Registry Platform (ICTRP), the Cochrane Central Register of Controlled Trials (CENTRAL), and the Specialised Registers of Cochrane Review Groups, including Epilepsy. We imposed no language restrictions. We contacted the manufacturers of pregabalin and authors in the field to identify any relevant unpublished studies.

SELECTION CRITERIA

We included randomised controlled trials comparing pregabalin with placebo or an alternative antiepileptic drug as an add-on for people of any age with drug-resistant focal epilepsy. Double-blind and single-blind trials were eligible for inclusion. The primary outcome was 50% or greater reduction in seizure frequency; secondary outcomes were seizure freedom, treatment withdrawal for any reason, treatment withdrawal due to adverse effects, and proportion of individuals experiencing adverse effects.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion and extracted the relevant data. Primary analyses were intention-to-treat (ITT). We presented summary risk ratios (RRs) and odds ratios (ORs) with 95% confidence intervals (CIs). We evaluated dose response in regression models. We carried out a risk of bias assessment for each included study using the Cochrane risk of bias tool and assessed the overall certainty of evidence using the GRADE approach.

MAIN RESULTS

We included 11 randomised controlled trials (3949 participants). Nine trials compared pregabalin to placebo. For the primary outcome, participants randomised to pregabalin were significantly more likely to attain a 50% or greater reduction in seizure frequency compared to placebo (RR 1.95, 95% CI 1.40 to 2.72, 9 trials, 2663 participants, low-certainty evidence). The odds of response doubled with an increase in dose from 300 mg/day to 600 mg/day (OR 1.99, 95% CI 1.74 to 2.28), indicating a dose-response relationship. Pregabalin was significantly associated with seizure freedom (RR 3.94, 95% CI 1.50 to 10.37, 4 trials, 1125 participants, moderate-certainty evidence). Participants were significantly more likely to withdraw from pregabalin treatment than placebo for any reason (RR 1.33, 95% CI 1.10 to 1.60; 9 trials, 2663 participants; moderate-certainty evidence) and for adverse effects (RR 2.60, 95% CI 1.86 to 3.64; 9 trials, 2663 participants; moderate-certainty evidence). Three trials compared pregabalin to three active-control drugs: lamotrigine, levetiracetam and gabapentin. Participants allocated to pregabalin were significantly more likely to achieve a 50% or greater reduction in seizure frequency than those allocated to lamotrigine (RR 1.47, 95% CI 1.03 to 2.12; 1 trial, 293 participants) but not those allocated to levetiracetam (RR 0.94, 95% CI 0.80 to 1.11; 1 trial, 509 participants) or gabapentin (RR 0.96, 95% CI 0.82 to 1.12; 1 trial, 484 participants). We found no significant differences between pregabalin and lamotrigine for seizure freedom (RR 1.39, 95% CI 0.40 to 4.83). However, significantly fewer participants achieved seizure freedom with add-on pregabalin compared to levetiracetam (RR 0.50, 95% CI 0.30 to 0.85). No data were reported for this outcome for pregabalin versus gabapentin. We detected no significant differences in treatment withdrawal rate for any reason or due to adverse effects, specifically, during either pooled analysis or subgroup analysis. Ataxia, dizziness, somnolence, weight gain, headache and fatigue were significantly associated with pregabalin than in active control. We rated the overall risk of bias in the included studies as low or unclear due to the possibility of publication bias and lack of methodological details provided. We assessed all the studies to be at a high risk of funding bias as they were all sponsored by Pfizer. We rated the certainty of the evidence as very low to moderate using the GRADE approach.

AUTHORS' CONCLUSIONS

For people with drug-resistant focal epilepsy, pregabalin when used as an add-on treatment was significantly more effective than placebo at producing a 50% or greater seizure reduction and seizure freedom. Results demonstrated efficacy for doses from 150 mg/day to 600 mg/day, with increasing effectiveness at 600 mg doses, although there were issues with tolerability at higher doses. However, the trials included in this review were of short duration, and longer-term trials are needed to inform clinical decision-making. This review focused on the use of pregabalin in drug-resistant focal epilepsy, and the results cannot be generalised to add-on treatment for generalised epilepsies. Likewise, no inference can be made about the effects of pregabalin when used as monotherapy.

Pregabalin as adjunctive therapy in adult and pediatric patients with generalized tonic-clonic seizures: A randomized, placebo-controlled trial

OBJECTIVE

Generalized tonic-clonic (GTC) seizures are the most common type of generalized seizure and more common in children than adults. This phase 3 study evaluated the efficacy and safety of pregabalin for GTC seizures in adults and children with epilepsy.

METHODS

This randomized, double-blind, multicenter study evaluated pregabalin (5 mg/kg/day or 10 mg/kg/day) vs placebo as adjunctive therapy for 10 weeks (following a 2-week dose escalation), in pediatric and adult patients (aged 5-65 years) with GTC seizures. Primary endpoint was change in log-transformed 28-day seizure rate during active treatment. Secondary endpoints included responder rates, defined as proportion of patients with ≥50% reduction in 28-day GTC seizure rate from baseline. Safety was monitored throughout.

RESULTS

Of 219 patients, 75, 72, and 72 were randomized to adjunctive pregabalin 5 mg/kg/day, 10 mg/kg/day, and placebo, respectively. Fifteen, 11, and 6 patients discontinued from the 5 mg/kg/day, 10 mg/kg/day, and placebo arms, respectively, most commonly due to adverse events (AEs; 10.7%, 6.9%, and 5.6%, respectively). A nonsignificant change in log-transformed mean 28-day seizure rate was seen with pregabalin 10 mg/kg/day vs placebo (least-squares [LS] mean difference -0.01 [95% confidence interval (CI) -0.19 to 0.16]; P = .8889) and with pregabalin 5 mg/kg/day vs placebo (LS mean difference 0.02 [CI -0.15 to 0.19]; P = .8121). Similar observations were noted for adults and children. No significant differences were seen for secondary endpoints with pregabalin vs placebo, including responder rate. The most common AEs (≥10%) were dizziness, headache, and somnolence. Most were of mild/moderate intensity. Seven patients had serious AEs, with one death in the placebo arm (sudden unexpected death in epilepsy).

SIGNIFICANCE

Adjunctive pregabalin treatment did not change GTC seizure rate in adults or children. The safety profile of pregabalin was similar to that known; treatment was well tolerated with few discontinuations due to AEs.

Pregabalin Population Pharmacokinetic and Exposure-Response Analyses for Focal Onset Seizures in Children (4-16 years) and Adults, to Support Dose Recommendations in Children

Pregabalin is approved in multiple countries as adjunctive therapy for adult patients with focal onset seizures (FOS; previously termed partial onset seizures). This study used population pharmacokinetic (PK) and exposure–response (E‐R) analyses from pooled pregabalin concentration and efficacy data to compare pregabalin exposure and E‐R relationships in pediatric and adult patients with FOS, to support pediatric dosage recommendations. A one‐compartment disposition model was used, with first‐order absorption and body surface area‐normalized creatinine clearance on clearance. Individual pregabalin average steady‐state concentrations were predicted and used in an E‐R analysis of efficacy. The E‐R relationship of pregabalin was similar in pediatric (4–16 years) and adult patients with FOS after accounting for differences in baseline natural log‐transformed 28‐day seizure rate and placebo effect. Population PK simulations showed that children aged 4–16 years and weighing ≥ 30 kg required pregabalin 2.5–10 mg/kg/day to achieve similar pregabalin exposure at steady‐state to adult patients receiving the approved doses of 150–600 mg/day. For children 4–16 years weighing < 30 kg, a higher pregabalin dose of 3.5–14 mg/kg/day was required to achieve equivalent exposure at steady‐state. The results support the dosage guidance provided in the pregabalin prescribing label, whereby pediatric patients (4–16 years) weighing < 30 kg should receive a 40% higher pregabalin dose (per kg of body weight) than patients weighing ≥ 30 kg to achieve similar exposure. Our combined modeling approach may provide guidance for future extrapolation assessment from adult to pediatric patients.

Unintentional exposure to pregabalin in ≤6-year-old children: a nationwide French Poison Control Center study

INTRODUCTION

In France, pregabalin is widely prescribed in adults but still not approved for children. We aimed to investigate the incidence of pregabalin exposure in ≤6-year-old children, to describe the characteristics and outcome of ingestions involving pregabalin alone, and to estimate a clinically relevant toxic dose in this population.

METHODS

Retrospective analysis of pregabalin exposures in ≤6-year-old children, collected by the French Poison Control Centers in 2004-2019. The incidence was estimated using pregabalin prescription data from the Health Improvement Network database (the French version of THIN). The poison severity score (PSS) was used to grade severity.

RESULTS

We found 313 unintentional immediate-release pregabalin ingestions in ≤6-year-old children. The number of cases per 100,000 pregabalin-treated adults increased over time (p < 0.001). One hundred twenty-six cases involving pregabalin alone (age, 2 years [1.6-3.0] (median [25th-75th percentiles]); median ingested dose 6.4 mg/kg [3.6-10.9]) were analyzed. No child presented an underlying neurological/cardiac disease and/or took concomitant medications. Most of the children (77%) remained asymptomatic (PSS0) while 21% and 2% developed minor (PSS1) or moderate (PSS2) neurological symptoms, respectively. No severe complications/fatalities were reported. All symptomatic children recovered within 24 h. The ingested pregabalin dose was positively correlated with PSS (p < 0.0001). Using a ROC curve approach (area under the curve, 0.85; p < 0.001), ingestion of ≥19.4 mg/kg pregabalin was appropriate to recommend hospital referral (sensitivity, 39% [95% confidence interval (95% CI), 24-56], specificity, 100% [95% CI, 96-100], predictive positive value, 100% [95% CI, 64-100], and negative predictive value, 85% [95% CI, 82-89]). Symptomatic children who ingested <19.4 mg/kg pregabalin developed minor symptoms.

CONCLUSION

Despite increasing prescriptions in adults in France, unintentional pregabalin ingestions in ≤6-year-old children remain rare and cause minimal toxicity. Children with no underlying neurological/cardiac disease and concomitant medication ingesting <19.4 mg/kg immediate-release pregabalin alone can be safely observed at home.