Prospective Open-Label, Single-Arm, Multicenter, Safety, Tolerability, and Pharmacokinetic Studies of Intravenous Levetiracetam in Children With Epilepsy

Application of Physiologically Based Pharmacokinetic Modeling to Characterize the Effects of Age and Obesity on the Disposition of Levetiracetam in the Pediatric Population

BACKGROUND

Levetiracetam is an antiseizure medication used for several seizure types in adults and children aged 1 month and older; however, due to a lack of data, pharmacokinetic (PK) variability of levetiracetam is not adequately characterized in certain populations, particularly neonates, children younger than 2 years of age, and children older than 2 years of age with obesity.

OBJECTIVE

This study aimed to address the gap by leveraging PK data from two prospective standard-of-care pediatric trials (n = 88) covering an age range from 1 month to 19 years, including those with obesity (64%), and applying a physiologically based PK (PBPK) modeling framework.

METHODS

A published PBPK model of levetiracetam for children aged 2 years and older was extended to pediatric patients younger than 2 years of age and patients older than 2 years of age with obesity by accounting for the obesity and age-related changes in PK using PK-Sim® software. The prospective pediatric data, along with the literature data for neonates and children younger than 2 years of age, were used to evaluate the extended PBPK models.

RESULTS

Overall, 82.4% of data fell within the 90% interval of model-predicted concentrations, with an average fold error within twofold of the accepted criteria. PBPK modeling revealed that children with obesity had lower weight-normalized clearances (0.053 L/h/kg) on average than children without obesity (0.063 L/h/kg). The effect of maturation was well-characterized, resulting in comparable PBPK-simulated, weight-normalized clearances for neonates and children younger than 2 years of age reported from the literature.

CONCLUSIONS

PBPK modeling simulations revealed that the current US FDA-labeled pediatric dosing regimen listed in the prescribing information can produce the required exposure of levetiracetam in these target populations with dose adjustments for children with obesity aged 4 years to younger than 16 years.

Determining the Safety and Tolerability of Rapid Administration of Undiluted Intravenous Levetiracetam in Pediatrics

Objective: Levetiracetam is widely used in the emergency setting. Safety and tolerability of undiluted levetiracetam is prevalent in adults but is limited in pediatrics. The purpose is to determine the safety and tolerability of rapid administration of undiluted levetiracetam in pediatric patients. Methods: A retrospective, single-center, observational study was conducted in pediatric patients who received undiluted levetiracetam intravenous push. The primary outcome was adverse reactions, extravasation, need for intravenous line replacement, and discontinuation due to adverse reactions. The secondary outcome was turnaround time between ordering and administering first doses. Results: One hundred fourteen patients were included. Injection site reactions occurred in 7 patients. Extravasation occurred in 4 patients. Two patients required intravenous line replacement. There were no adverse events leading to discontinuation of levetiracetam. No difference was seen in the time from order to administration. Conclusion: Rapid administration of undiluted levetiracetam in pediatric patients was safe and well tolerated.

Physiologically-based pharmacokinetic modeling of oxcarbazepine and levetiracetam during adjunctive antiepileptic therapy in children and adolescents

Oxcarbazepine (OXZ) and levetiracetam (LEV) are two new generation anti‐epileptic drugs, often co‐administered in children with enzyme‐inducing antiepileptic drugs (EIAEDs). The anti‐epileptic effect of OXZ and LEV are linked to the exposure of OXZ’s active metabolite 10‐monohydroxy derivative (MHD) and (the parent) LEV, respectively. However, little is known about the confounding effect of age and EIAEDs on the pharmacokinetics (PKs) of MHD and LEV. To address this knowledge gap, physiologically‐based pharmacokinetic (PBPK) modeling was performed in the PK‐Sim software using literature data from children greater than or equal to 2 years of age. Age‐related changes in clearance (CL) of MHD and LEV were characterized, both in the presence (group 1) and absence (group 2) of concomitant EIAEDs. The drug‐drug interaction effect of EIAEDs was estimated as the difference in CL estimates between groups 1 and 2. PBPK modeling suggests that bodyweight normalized CL (ml/min/kg) is higher in younger children than their older counterparts (i.e., due to an influence of age). Concomitant EIAEDs further increase MHD’s CL to a fixed extent of 25% at any age, but EIAEDs’ effect on LEV’s CL increases with age from 20% (at 2 years) to 30% (at adolescence). Simulations with the maximum recommended doses (MRDs) revealed that children between 2 and 4 years and greater than 4 years, who are not on EIAEDs, are at risk of exceeding the reference exposure range for OXZ and LEV, respectively. This analysis demonstrates the use of PBPK modeling in understanding the confounding effect of age and comedications on PKs in children and adolescents.

Treating Status Epilepticus: Phenytoin Versus Levetiracetam

For decades, phenytoin has been the drug of choice for the treatment of epilepsy but also the second-line treatment for status epilepticus (SE). However, newer antiepileptic drugs (AEDs) have emerged as safer alternatives for the suppression of seizures. Consequently, phenytoin has recently fallen under scrutiny in the research world, prompting many studies to compare its efficacy to these other drugs, most notably levetiracetam. Levetiracetam is a second-generation AED, which is gaining wide clinical use as the second-line agent in treating SE patients. This review focuses on several clinical studies that have directly compared the effectiveness of phenytoin and levetiracetam in suppressing SE seizure activity. Additionally, this review highlights several advantages of using levetiracetam over phenytoin in this clinical context.

Levetiracetam versus phenytoin in children with status epilepticus

Background:

To compare the efficacy and safety of intravenous levetiracetam and phenytoin in status epilepticus.

Methodology:

A prospective, randomized controlled, nonblinded study was conducted in children 1 month to 12 years of age with active seizure and with status epilepticus. A total of 104 children were randomly allocated to either group 1 (levetiracetam) or group 2 (phenytoin) on the basis of computer-generated random number table. Children already on antiepileptic drugs, very sick children with shock, impending respiratory failure, or head injury, and children hypersensitive to phenytoin or levetiracetam were excluded. Data analysis was done by IBM SPSS statistics.

Results:

The mean age was 4.09 years with a male preponderance with the most common type of seizure being generalized type (74%). The seizures were controlled in all 104 patients initially within 40 min. Seizure control for 24 h was significantly better in group 1 (96%) when compared with group 2 (59.6%) (P = 0.0001). Minibolus of drug was given in 28.8% in group 1 and 46.2% in group 2 (P = 0.068). The seizure recurrence in groups 1 and 2 in the first hour was 1.9% and 5.8%, respectively (P = 0.61), whereas the recurrence between 1 and 24 h was significantly more in group 1 (34.6%) when compared with group 2 (3.8%) (P = 0.0001). The mean time to control seizure was comparable between both the groups (P = 0.71). There was no significant adverse effect in both the groups.

Conclusion:

Levetiracetam is more effective than phenytoin for seizure control for 24 h in children with status epilepticus, and it is safe and effective as a second-line therapy.

Etiology of neonatal seizures and maintenance therapy use: a 10-year retrospective study at Toulouse Children's hospital

BACKGROUND

No guidelines exist concerning the maintenance antiepileptic drug to use after neonatal seizures. Practices vary from one hospital to another. The aim of this study was to investigate etiologies and to report on the use of maintenance antiepileptic therapy in our population of full-term neonates presenting neonatal seizures.

METHODS

From January 2004 to October 2014, we retrospectively collected data from all full-term neonates with neonatal seizures admitted to the Children's Hospital of Toulouse, France.

RESULTS

Two hundred and forty-three neonates were included (59% males, 48% electroencephalographic confirmation). The frequencies of etiologies of neonatal seizures were: hypoxic-ischemic encephalopathy (HIE) (n = 91; 37%), ischemic infarction (n = 36; 15%), intracranial hemorrhage (n = 29; 12%), intracranial infection (n = 19; 8%), metabolic or electrolyte disorders (n = 9; 3%), inborn errors of metabolism (n = 5; 2%), congenital malformations of the central nervous system (n = 11; 5%), epileptic syndromes (n = 27; 12%) and unknown (n = 16; 7%). A maintenance therapy was prescribed in 180 (72%) newborns: valproic acid (n = 123), carbamazepine (n = 28), levetiracetam (n = 17), vigabatrin (n = 2), and phenobarbital (n = 4). In our cohort, the choice of antiepileptic drug depended mainly on etiology. The average duration of treatment was six months.

CONCLUSIONS

In our cohort, valproic acid was the most frequently prescribed maintenance antiepileptic therapy. However, the arrival on the market of new antiepileptic drugs and a better understanding of the physiopathology of genetic encephalopathies is changing our practice.

TRIAL REGISTRATION

Retrospectively registered. Patient data were reported to the "Commission Nationale Informatique et Libertés" under the number 2106953 .

Pharmacokinetic and Pharmacodynamic Evaluation of Intravenous Levetiracetam in Children With Epilepsy

This study aimed to evaluate the safety and tolerability of intravenous (IV) levetiracetam (LEV) as a monotherapy in children aged 1 month-16 years and to explore the pharmacokinetics (PK) of IV LEV and the time to seizure after IV then oral administration of LEV in pediatric children with epilepsy. Children diagnosed with acute unprovoked seizures requiring in-hospital IV LEV administration were included. After administration, the clinical seizure outcomes, side effects, and the Korean-Child Behavior Checklist were monitored and the PK and repeated time to seizure were analyzed via modeling using NONMEM software. Overall, 37 children with epilepsy were enrolled and underwent a PK analysis (median age, 4.6 years; median weight, 18.0 kg). Nine children (24.3%) had seizure recurrence during the follow-up period (median, 3.8 months) and 5 children (13.5%) experienced LEV-associated adverse events such as irritability (n = 2; 5.4%) and somnolence (n = 3; 8.1%). The plasma LEV concentrations after IV LEV were best described by a one-compartment linear PK model. Only body weight was associated with both the clearance and volume of distribution of LEV. The Weibull distribution model described the time to seizure recurrence well; no statistically significant predictor for the time to seizure was identified. Therefore, IV LEV was a well-tolerated and effective alternative in children with acute unprovoked seizures, and models for the PK and time to repeated seizure recurrence after LEV were successfully developed. In particular, the current use of a weight-based IV LEV dosing regimen in pediatric children is practical.

IV Levetiracetam versus IV Phenytoin in Childhood Seizures: A Randomized Controlled Trial

OBJECTIVES

To compare the efficacy of IV phenytoin and IV levetiracetam in acute seizures.

DESIGN

Randomized controlled trial.

SETTING

Tertiary care hospital, November 2012 to April 2014.

PATIENTS

100 children aged 3-12 yrs of age presenting with acute seizures.

INTERVENTION

Participants randomly received either IV phenytoin 20 mg/kg (n = 50) or IV levetiracetam 30 mg/kg (n = 50). Patients who were had seizures at presentation received IV diazepam prior to these drugs.

OUTCOME MEASURES

Primary: Absence of seizure activity within next 24 hrs.Secondary: Stopping of clinical seizure activity within 20 mins of first intervention, change in cardiorespiratory parameters, and achievement of therapeutic drug levels.

RESULTS

Two groups were comparable in patient characteristics and seizure type (P > 0.05). Of the 100 children, 3 in levetiracetam and 2 in phenytoin group had a repeat seizure in 24 hrs, efficacy was comparable (94% vs 96%, P > 0.05). Of these, 18 (36%) in phenytoin and 12 (24%) in levetiracetam group received diazepam. Sedation time was 178.80 ±97.534 mins in phenytoin and 145.50 ±105.208 mins in levetiracetam group (P = 0.346). Changes in cardiorespiratory parameters were similar in both groups except a lower diastolic blood pressure with phenytoin (P = 0.023). Therapeutic drug levels were achieved in 38 (76%) children both at 4 and 24 hrs with phenytoin, compared to 50 (100%) and 48 (98%) at 1 and 24 hrs with levetiracetam (P < 0.05).

CONCLUSION

Intravenous levetiracetam and phenytoin have similar efficacy in preventing seizure recurrences for 24 hrs in children 3-12 years presenting with acute seizures.

IV Levetiracetam versus IV Phenytoin in Childhood Seizures: A Randomized Controlled Trial

Objectives:

To compare the efficacy of IV phenytoin and IV levetiracetam in acute seizures.

Design:

Randomized controlled trial.

Setting:

Tertiary care hospital, November 2012 to April 2014.

Patients:

100 children aged 3–12 yrs of age presenting with acute seizures.

Intervention:

Participants randomly received either IV phenytoin 20 mg/kg (n = 50) or IV levetiracetam 30 mg/kg (n = 50). Patients who were had seizures at presentation received IV diazepam prior to these drugs.

Outcome Measures:

Primary: Absence of seizure activity within next 24 hrs.

Secondary: Stopping of clinical seizure activity within 20 mins of first intervention, change in cardiorespiratory parameters, and achievement of therapeutic drug levels.

Results:

Two groups were comparable in patient characteristics and seizure type (P > 0.05). Of the 100 children, 3 in levetiracetam and 2 in phenytoin group had a repeat seizure in 24 hrs, efficacy was comparable (94% vs 96%, P > 0.05). Of these, 18 (36%) in phenytoin and 12 (24%) in levetiracetam group received diazepam. Sedation time was 178.80 ±97.534 mins in phenytoin and 145.50 ±105.208 mins in levetiracetam group (P = 0.346). Changes in cardiorespiratory parameters were similar in both groups except a lower diastolic blood pressure with phenytoin (P = 0.023). Therapeutic drug levels were achieved in 38 (76%) children both at 4 and 24 hrs with phenytoin, compared to 50 (100%) and 48 (98%) at 1 and 24 hrs with levetiracetam (P < 0.05).

Conclusion:

Intravenous levetiracetam and phenytoin have similar efficacy in preventing seizure recurrences for 24 hrs in children 3–12 years presenting with acute seizures.

Safety of Levetiracetam in Paediatrics: A Systematic Review

Objective

To identify adverse events (AEs) associated with Levetiracetam (LEV) in children.

Methods

Databases EMBASE (1974-February 2015) and Medline (1946-February 2015) were searched for articles in which paediatric patients (≤18 years) received LEV treatment for epilepsy. All studies with reports on safety were included. Studies involving adults, mixed age population (i.e. children and adults) in which the paediatric subpopulation was not sufficiently described, were excluded. A meta-analysis of the RCTs was carried out and association between the commonly reported AEs or treatment discontinuation and the type of regimen (polytherapy or monotherapy) was determined using Chi² analysis.

Results

Sixty seven articles involving 3,174 paediatric patients were identified. A total of 1,913 AEs were reported across studies. The most common AEs were behavioural problems and somnolence, which accounted for 10.9% and 8.4% of all AEs in prospective studies. 21 prospective studies involving 1120 children stated the number of children experiencing AEs. 47% of these children experienced AEs. Significantly more children experienced AEs with polytherapy (64%) than monotherapy (22%) (p<0.001). Levetiracetam was discontinued in 4.5% of all children on polytherapy and 0.9% on monotherapy (p<0.001), the majority were due to behavioural problems.

Conclusion

Behavioural problems and somnolence were the most prevalent adverse events to LEV and the most common causes of treatment discontinuation. Children on polytherapy have a greater risk of adverse events than those receiving monotherapy.

Intravenous levetiracetam in Thai children and adolescents with status epilepticus and acute repetitive seizures

BACKGROUND

Intravenous levetiracetam is an option for treatment of status epilepticus (SE) and acute repetitive seizures (ARS). However, there have been relatively few studies with children and adolescents. Also, an appropriate dosage has yet to be determined.

AIM

This study investigated the safety and the efficacy of levetiracetam for intravenous treatment of convulsive status epilepticus and acute repetitive seizures in children and adolescents.

METHOD

Retrospectively, the study reviewed the medical records of 19 male and 31 female patients under 18 years of age who had received intravenous levetiracetam treatment either for acute repetitive seizures or for convulsive status epilepticus. The patients were admitted between April 1st, 2010 and December 31st, 2011 to the Department of Pediatrics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand. Data were collected on underlying illnesses, etiology of seizures, indication for levetiracetam therapy, initial dosage, rate of infusion, untoward effects during infusion and emerged complications. Efficacy of treatment was defined as the termination of seizure within 30 min of completing levetiracetam infusion and no seizure recurrence within 6 h of initial treatment.

RESULTS

The age range of the 50 patients was from one day to 18 years (mean 79.6 months). The analysis included 52 episodes of 34 acute repetitive seizures (63.4%) and 18 convulsive status epilepticus (34.6%). Infusion rates ranged from 2 to 66 mg/kg/min (mean 29.6). Cessation of seizure was obtained in 59.6% of 52 episodes. Patients with underlying drug resistant epilepsy did not respond to levetiracetam therapy as well as patients with other etiology of seizures. There were no adverse drug reactions or untoward effects observed during the therapy.

CONCLUSION

Intravenous administration of levetiracetam is safe and effective for treatment of acute repetitive seizures and convulsive status epilepticus in children and adolescents. Failure of treatment may be related to underlying drug resistant epilepsy. Further study of appropriate initial dosage and pharmacokinetic variations in the patients is needed as possible explanation of the unresponsiveness.

Pharmacokinetics of the antiepileptic drug levetiracetam in healthy Japanese and Caucasian volunteers following intravenous administration

The intravenous (iv) formulation of levetiracetam has been available in clinical practice worldwide for several years, but not in Japan. Two open-label studies were conducted: Study A evaluated the bioequivalence of iv and oral tablet formulations in healthy Japanese volunteers; and Study B subsequently compared the pharmacokinetics of iv levetiracetam in healthy Japanese and Caucasian volunteers. Study A had a randomised, two-way crossover design; a single 1,500 mg levetiracetam dose was administered as a 15-min iv infusion and as 3 × 500 mg oral tablets to Japanese volunteers. In Study B, 1,500 mg levetiracetam was administered as single and repeated 15-min iv infusions to Japanese and Caucasian volunteers. Overall, 26/27 volunteers completed Study A and 32/32 (16 Japanese; 16 Caucasian) completed Study B. In Study A, the point estimate and 90 % confidence interval (CI) for the geometric least squares mean (LSM) ratio (iv vs oral) were fully included within the acceptance range for bioequivalence (0.85-1.25) for the area under plasma concentration-time curve from 0 to last quantifiable observation (AUClast 0.97 [0.95, 0.99]), but not for the maximum plasma concentration (C max 1.64 [1.47, 1.83]). In Study B, after a single iv infusion, the point estimates (90 % CI) for the geometric LSM ratio (Japanese vs Caucasian) for body weight-normalised C max and AUClast were 1.21 (1.07, 1.36) and 0.97 (0.90, 1.04), respectively. Corresponding values after repeated iv infusions were C max,ss 1.01 (0.91, 1.12) and AUCτ,ss 0.89 (0.83, 0.96). Levetiracetam was well tolerated in both studies. Study A did not demonstrate the bioequivalence of single doses of levetiracetam 1,500 mg administered as an iv infusion and as oral tablets in healthy Japanese adults. Study B, however, showed that pharmacokinetic profiles were generally similar between Japanese and Caucasian adults after single and repeated iv infusions of levetiracetam 1,500 mg.

Clinical pharmacology and pharmacokinetics of levetiracetam

Status epilepticus and acute repetitive seizures still pose a management challenge despite the recent advances in the field of epilepsy. Parenteral formulations of old anticonvulsants are still a cornerstone in acute seizure management and are approved by the FDA. Intravenous levetiracetam (IV LEV), a second generation anticonvulsant, is approved by the FDA as an adjunctive treatment in patients 16 years or older when oral administration is not available. Data have shown that it has a unique mechanism of action, linear pharmacokinetics and no known drug interactions with other anticonvulsants. In this paper, we will review the current literature about the pharmacology and pharmacokinetics of IV LEV and the safety profile of this new anticonvulsant in acute seizure management of both adults and children.

Efficacy and tolerability of intravenous levetiracetam in childrens

Intractable epilepsy in children poses a serious medical challenge. Acute repetitive seizures and status epilepticus leads to frequent emergency room visits and hospital admissions. Delay of treatment may lead to resistance to the first-line anticonvulsant therapies. It has been shown that these children continue to remain intractable even after acute seizure management with approved Food and Drug Administration (FDA) agents. Intravenous levetiracetam, a second-generation anticonvulsant was approved by the FDA in 2006 in patients 16 years and older as an alternative when oral treatment is not an option. Data have been published showing that intravenous levetiracetam is safe and efficacious, and can be used in an acute inpatient setting. This current review will discuss the recent data about the safety and tolerability of intravenous levetiracetam in children and neonates, and emphasize the need for a larger prospective multicenter trial to prove the efficacy of this agent in acute seizure management.