Single-dose pharmacokinetics of levetiracetam in healthy Chinese male subjects

Predictive Performance of Population Pharmacokinetic Models of Levetiracetam in Children and Evaluation of Dosing Regimen

Levetiracetam is a broad-spectrum antiepileptic drug that exhibits high interindividual variability in serum concentrations in children. A population pharmacokinetic approach can be used to explain this variability and optimize dosing schemes. The objectives are to identify the best predictive population pharmacokinetic model for children and to evaluate recommended doses using simulations and Bayesian forecasting. A validation cohort included children treated with levetiracetam who had a serum drug concentration assayed during therapeutic drug monitoring. We assessed the predictive performance of all the population pharmacokinetic models published in the literature using mean prediction errors, root mean squared errors, and visual predictive checks. A population model was finally constructed on the data, and dose simulations were performed to evaluate doses. We included 267 levetiracetam concentrations ranging from 2 to 69 mg/L from 194 children in the validation cohort. Six published models were externally evaluated. Most of the models underestimated the variability of our population. A 1-compartment model with first-order absorption and elimination with allometric scaling was finally fitted on our data. In our cohort, 57% of patients had a trough concentration <12 mg/L and 12% <5 mg/L. To reach a trough concentration >5 mg/L, doses ≥30 mg/kg/d for patients ≤50 kg and ≥2000 mg/d for patients >50 kg are required. In our population, a high percentage of children had low trough concentrations. Our population pharmacokinetic model could be used for therapeutic drug monitoring of levetiracetam in children.

Population Pharmacokinetics of Levetiracetam: a Systematic Review

BACKGROUND

The use of levetiracetam (LEV) has been increasing given its favorable pharmacokinetic profile. Numerous population pharmacokinetic studies for LEV have been conducted. However, there are some discrepancies regarding factors affecting its pharmacokinetic variability. Therefore, this systematic review aimed to summarize significant predictors for LEV pharmacokinetics as well as the need for dosage adjustments.

METHODS

We performed a systematic search for population pharmacokinetic studies of LEV conducted using a nonlinear-mixed effect approach from PubMed, Scopus, CINAHL Complete, and Science Direct databases from their inception to March 2020. Information on study design, model methodologies, significant covariate-parameter relationships, and model evaluation was extracted. The quality of the reported studies was also assessed.

RESULTS

A total of 16 studies were included in this review. Only two studies were conducted with a two-compartment model, while the rest were performed with a one-compartment structure. Bodyweight and creatinine clearance were the two most frequently identified covariates on LEV clearance (CLLEV). Additionally, postmenstrual age (PMA) or postnatal age (PNA) were significant predictors for CLLEV in neonates. Only three studies externally validated the models. Two studies conducted pharmacodynamic models for LEV with relatively small sample size.

CONCLUSION

Significant predictors for LEV pharmacokinetics are highlighted in this review. For future research, a population pharmacokinetic-pharmacodynamic model using a larger sample size should be conducted. From a clinical perspective, the published models should be externally evaluated before clinical implementation.

Pharmacokinetic and pharmacodynamic modeling of levetiracetam: investigation of factors affecting the clinical outcome

This study aimed to evaluate the pharmacokinetics and pharmacodynamics of oral levetiracetam therapy in drug refractory adult epileptic outpatients, as well as factors affecting them. Concentration-time data were collected at steady state, while seizure recurrence was monitored for 13 months. Non-linear mixed effects modeling was applied, and covariates assessed included weight, height, age, daily dose and creatinine clearance.Plasma concentrations of levetiracetam were best described by a one-compartment pharmacokinetic model (V/F = 34.7 L) with first-order absorption (ka = 0.616 h^-1) and clearance (CL/F = 3.26 L/h). Patient's CrCL was found to significantly affect levetiracetam clearance (beta = 0.795). Time to seizure occurrence followed an exponential distribution and the mean time to seizure occurrence was estimated Te = 22.08 days. Seizure rate per month followed a Poisson distribution, while mean seizure rate per month was estimated λ = 1.33. Daily dose significantly affected the mean estimated time to seizure (beta = -2.2) and the mean monthly seizure rate (beta = 2.27) in a reverse way. Using discrete time Markov chains, it was shown that the transition probability from focal seizures to focal to bilateral tonic-clonic is significantly altered in relation to patient's CrCL.Simulations showed that dose should be adjusted in relation to CrCL, while low doses of levetiracetam are more effective for seizure control. Modeling and simulation in every-day clinical practice may provide significant information for the optimization of seizure control using well-known agents.

Adjunctive levetiracetam in the treatment of Chinese and Japanese adults with generalized tonic-clonic seizures: A double-blind, randomized, placebo-controlled trial

Objective

To assess the efficacy, safety, and tolerability of adjunctive levetiracetam (LEV) in Chinese and Japanese adults with generalized tonic-clonic (GTC) seizures (N01159; NCT01228747).

Methods

This double-blind, randomized, placebo-controlled, multicenter phase III trial comprised: 4-week retrospective and 4-week prospective baseline, 12-week dose-adjustment, and 16-week evaluation periods. Chinese and Japanese patients ≥16 years old with idiopathic generalized, symptomatic generalized, or undetermined epilepsy with GTC seizures received a single-blind placebo during the prospective baseline, and then were randomized 1:1 to placebo or LEV 1,000 mg/day administered twice daily. Patients reporting GTC seizures up to week 8 had the LEV dosage increased to 3,000 mg/day. The primary efficacy variable was percent reduction from combined baseline in GTC seizures/week during the 28-week treatment period.

Results

Overall, 251 patients were randomized (208 from China; 43 from Japan); 141 (56.2%) completed the 28-week treatment period. Least-squares mean percent reduction from combined baseline in GTC seizures/week (treatment period) was placebo 12.6% versus LEV 68.8% (95% confidence interval, 44.0-68.2; p < 0.0001). GTC seizure frequency reduction occurred in both patients with idiopathic and symptomatic generalized epilepsy. The 50% responder rate (treatment period) was placebo 28.4% versus LEV 77.8%. Freedom from GTC seizures (evaluation period) was placebo 3.1% versus LEV 29.6%. Incidence of treatment-emergent adverse events (TEAEs; treatment period) was placebo 52.0% versus LEV 57.1%; most frequently nasopharyngitis, protein in urine, decreased platelet count, and pyrexia. Incidence of TEAEs leading to discontinuation was 4.8% versus 3.2%; incidence of serious TEAEs was 3.2% versus 0.8% for placebo and LEV, respectively; 3 patients taking placebo died versus none taking LEV.

Significance

In this trial, adjunctive LEV 1,000-3,000 mg/day was effective in reducing GTC seizure frequency in Chinese and Japanese patients ≥16 years old with GTC seizures. Seizure reduction occurred in both patients with idiopathic and symptomatic generalized epilepsy. LEV was well tolerated in this population.

Randomized Comparative Bioavailability of a Novel Three-Dimensional Printed Fast-Melt Formulation of Levetiracetam Following the Administration of a Single 1000-mg Dose to Healthy Human Volunteers Under Fasting and Fed Conditions

Background

Rapidly disintegrating or ‘fast-melt’ oral formulations have been developed recently to facilitate drug intake among patients. Even though these formulations have helped to improve therapy adherence, some of their limitations include: the dissolution time, their facility to be swallowed, and the dosage strengths that may be accommodated. To overcome these limitations, a novel, porous, quickly disintegrating, and easier-to-swallow fast-melt formulation based on powder-liquid, three-dimensional printing (3DP) technology has been developed.

Objective

To determine and compare the relative bioavailability of a novel 3DP fast melt containing levetiracetam in healthy male and female subjects.

Methods

This study included 33 subjects in a three-way crossover design. The 3DP fast-melt formulation was compared against the conventional immediate-release tablet of levetiracetam (Keppra^®) after a single 1000-mg dose administration under fasting conditions following the bioequivalence criteria used by the US Food and Drug Administration. This study also evaluated the food effect on the bioavailability of the levetiracetam 3DP fast melt. A small sip of liquid was used to administer the fast-melt formulation.

Results

The novel 3DP fast melt showed rapid oral disintegration (mean duration of 11 s from a sip of water to completion of swallowing) following its administration, and did not affect the pharmacokinetic profile of levetiracetam. A lower absorption peak was observed after administration of the 3DP fast melt under fed conditions, as expected. In addition, time of maximum measured plasma concentration was delayed by approximately 3.5 h under fed conditions. These effects are unlikely to be of clinical significance with long-term administration, and may help reduce the adverse events and facilitate compliance. Finally, no change in the oral mucosa was observed with the 3DP fast melt while being as safe and well tolerated as the standard levetiracetam tablet.

Conclusion

This study quantified the rapid disintegration of the 3DP levetiracetam fast melt and confirmed its equivalent rate and extent of absorption to the conventional immediate-release tablet in the fasted state, using standard bioequivalence criteria.

Brivaracetam in the treatment of focal and idiopathic generalized epilepsies and of status epilepticus

Brivaracetam is the latest approved antiepileptic drug in focal epilepsy and exhibits high affinity as SV2A-ligand. More than two thousand patients have received brivaracetam within randomized placebo-controlled trials. Significant median seizure reduction rates of 30.5% to 53.1% for 50 mg/d, 32.5% to 37.2% for 100 mg/d and 35.6% for 200 mg/d were reported. Likewise, 50% responder rates were 32.7% to 55.8% for 50 mg/d, 36% to 38.9% for 100 mg/d and 37.8% for 200 mg/d. Overall, brivaracetam is well tolerated. The main adverse events are fatigue, dizziness, and somnolence. Immediate switch from levetiracetam to brivaracetam at a conversion ratio between 10:1 to 15:1 is feasible, and might alleviate the behavioral side effects associated with levetiracetam. Brivaracetam has the potential to perform as an important, possibly broad-spectrum AED, initially in patients with drug-refractory epilepsies. Its intravenous formulation may be a new and desirable alternative for status epilepticus, but there is so far no experience in these patients.

Levetiracetam: a review of its use in epilepsy

Levetiracetam (Keppra®, E Keppra®) is an established second-generation antiepileptic drug (AED). Worldwide, levetiracetam is most commonly approved as adjunctive treatment of partial onset seizures with or without secondary generalization; other approved indications include monotherapy treatment of partial onset seizures with or without secondary generalization, and adjunctive treatment of myoclonic seizures associated with juvenile myoclonic epilepsy and primary generalized tonic-clonic (GTC) seizures associated with idiopathic generalized epilepsy. Levetiracetam has a novel structure and unique mechanisms of action. Unlike other AEDs, the mechanisms of action of levetiracetam appear to involve neuronal binding to synaptic vesicle protein 2A, inhibiting calcium release from intraneuronal stores, opposing the activity of negative modulators of GABA- and glycin-gated currents and inhibiting excessive synchronized activity between neurons. In addition, levetiracetam inhibits N-type calcium channels. Levetiracetam is associated with rapid and complete absorption, high oral bioavailability, minimal metabolism that consists of hydrolysis of the acetamide group, and primarily renal elimination. It lacks cytochrome P450 isoenzyme-inducing potential and is not associated with clinically significant pharmacokinetic interactions with other drugs, including other AEDs. The efficacy of oral immediate-release levetiracetam in controlling seizures has been established in numerous randomized, double-blind, controlled, multicentre trials in patients with epilepsy. Adjunctive levetiracetam reduced the frequency of seizures in paediatric and adult patients with refractory partial onset seizures to a significantly greater extent than placebo. Monotherapy with levetiracetam was noninferior to that with carbamazepine controlled release in controlling seizures in patients with newly diagnosed partial onset seizures. Levetiracetam also provided seizure control relative to placebo as adjunctive therapy in patients with idiopathic generalized epilepsy with myoclonic seizures or GTC seizures. In addition, patients receiving oral levetiracetam showed improvements in measures of health-related quality of life relative to those receiving placebo. Although treatment-emergent adverse events were commonly reported in the clinical trials of levetiracetam, the overall proportion of patients who experienced at least one treatment-emergent adverse event was broadly similar in the levetiracetam and placebo treatment groups, with most events being mild to moderate in severity. Levetiracetam is not associated with cognitive impairment or drug-induced weight gain, but has been associated with behavioural adverse effects in some patients.

Efficacy and safety of levetiracetam as adjunctive therapy in adult patients with uncontrolled partial epilepsy: the Asia SKATE II Study

This study evaluated the safety and efficacy of levetiracetam as adjunctive therapy for partial seizures in everyday clinical practice in Asian populations. Patients aged > or =16 years (N=251) with inadequately controlled partial epilepsy were recruited from 29 centers across Asia. Levetiracetam was added to existing antiepileptic medication for 16 weeks at a starting dose of 500 or 1000 mg/day and titrated to a maximum of 3000 mg/day according to clinical response. The study completion rate was 86.9%. Adverse events were reported by 73.3% of patients and were generally mild, leading to treatment withdrawal in only 7.2%. The most common adverse events were somnolence (30.3%) and dizziness (14.7%). Compared with pretreatment baseline, 44.0% of patients had a > or =50% reduction in seizure frequency, with a median reduction of 46.4%, and 17.7% became seizure free during the treatment period. Levetiracetam was well tolerated and efficacious as adjunctive therapy for partial epilepsy in clinical practice among Asian populations.

Clinical efficacy and cognitive and neuropsychological effects of levetiracetam in epilepsy: an open-label multicenter study

The aim of this prospective, multicenter, open-label study was to investigate the efficacy of levetiracetam (LEV) and determine its effects on cognitive and neuropsychological function. Sixty-nine patients were evaluated for effects of LEV on seizure control, cognitive (Mini-Mental State Examination [MMSE]) and neuropsychological (Symptom Checklist-90 Revised [SCL-90-R]) functions, and quality of life (Quality of Life in Epilepsy--10 [QOLIE-10]) assessments at 3 and 12 months of follow-up. Thirty-nine percent of patients achieved seizure freedom, and 68% had a > or =50% seizure frequency reduction after 1 year of LEV (1235.5+/-392.7 mg/day). There were also significant improvements in mean MMSE score and in the recall and language items of MMSE. There were modest improvements in interpersonal sensitivity and paranoid ideation scales of the SCL-90-R, and improvements in cognition and medication effect items of the QOLIE-10. The results demonstrate that LEV not only effectively reduces seizure frequency, but also possibly contributes to improvements in neuropsychological functions such as recall, language, interpersonal sensitivity, and paranoid ideation.

Economic Evaluation of Add-on Levetiracetam for the Treatment of Refractory Partial Epilepsy in Korea

OBJECTIVE

This study estimated the expected cost-effectiveness ratio expressed as the incremental cost per seizure-free day (SFD) gained and the incremental cost per quality adjusted life year (QALY) gained when using levetiracetam (LEV) as add-on therapy from a third-party payer perspective.

METHODS

A 1-year dose-escalation decision-tree model comparing LEV plus standard therapy (ST) with ST alone was designed to combine transition probabilities, costs and outcomes. The short-term outcomes and probabilities were derived from a prospective, open-label clinical trial with 100 Korean adults with refractory partial epilepsy. All data for the direct medical costs were derived from Korean cost data extracted from reports published by the National Health Insurance Corporation.

RESULTS

The average gain in SFDs attributed to LEV add-on was 18.3 days per patient per year and the incremental cost-effectiveness ratios (ICERs) for LEV add-on were US$ 44 per SFD per patient and US$ 11,084 per QALY gained. All sensitivity analyses showed that the model was robust to the assumptions made.

CONCLUSION

The economic evaluation indicates that, given a wide range of assumptions, the increased cost of treating patients having refractory partial epilepsy with LEV may be partially offset by a reduction in other direct medical costs. This reduction is a consequence of an increase in the number of SFDs and improved quality of life.

Multicenter double-blind, randomized, placebo-controlled trial of levetiracetam as add-on therapy in Chinese patients with refractory partial-onset seizures

PURPOSE

To evaluate efficacy and tolerability of levetiracetam (LEV; Keppra) as add-on therapy in Chinese patients with refractory partial-onset seizures.

METHODS

In this multicenter, double-blind, randomized, placebo-controlled trial, 206 patients aged 16-70 years with uncontrolled partial-onset seizures were randomized to receive LEV (n =103) or placebo (n =103); 202 patients (LEV, n =102; placebo, n = 100) comprised the intent-to-treat population. An 8-week historical baseline period confirmed eligibility according to seizure count. The 16-week treatment period consisted of a 4-week up-titration period (LEV, 1,000-3,000 mg/day in two equal divided doses) followed by a 12-week maintenance period. Efficacy assessments were based on weekly frequency of partial-onset seizures during the 16-week treatment period.

RESULTS

LEV significantly decreased weekly partial-onset seizure frequency over placebo by 26.8% (p < 0.001). Median percentage reductions in weekly partial-onset seizure frequency from historical baseline were 55.9% for LEV and 13.7% for placebo (p < 0.001). The >or=50% responder rates were 55.9% for LEV, compared with 26.0% for placebo (p < 0.001). Freedom from partial-onset seizures during treatment period was achieved by 11 LEV patients (10.8%) and 2 placebo patients (2.0%) (p = 0.012). Adverse events were reported by 65 LEV-treated patients (63.1%) and 62 placebo-treated patients (60.2%); most were of mild-to-moderate intensity. The most common adverse events were somnolence (LEV, 17.5%; placebo, 17.5%), decreased platelet count (LEV, 9.7%; placebo, 9.7%), and dizziness (LEV, 7.8%; placebo, 13.6%).

DISCUSSION

Add-on LEV was effective and well-tolerated in Chinese patients with refractory partial-onset seizures.