Levetiracetam extended release and levetiracetam immediate release as adjunctive treatment for partial-onset seizures: an indirect comparison of treatment-emergent adverse events using meta-analytic techniques

Duration of Prophylactic Levetiracetam After Surgery for Brain Tumor: A Prospective Randomized Trial

BACKGROUND

Levetiracetam is commonly used as a prophylactic antiseizure medication in patients undergoing surgical resection of brain tumors.

OBJECTIVE

To quantitate side effects experienced in patients treated with 1 week vs 6 weeks of prophylactic levetiracetam using validated measures for neurotoxicity and depression.

METHODS

Patients undergoing surgical resection of a supratentorial tumor with no seizure history were randomized within 48 hours of surgery to receive prophylactic levetiracetam for the duration of either 1 or 6 weeks. Patients were given oral levetiracetam extended release 1000 mg during the first part of this study. Owing to drug backorder, patients enrolled later in this study received levetiracetam 500 mg BID. The primary outcome was the change in the neurotoxicity score 6 weeks after drug initiation. The secondary outcome was seizure incidence.

RESULTS

A total of 81 patients were enrolled and randomized to 1 week (40 patients) or 6 weeks (41 patients) of prophylactic levetiracetam treatment. The neurotoxicity score slightly improved in the overall cohort between baseline and reassessment. There was no significant difference between groups in neurotoxicity or depression scores. Seizure incidence was low in the entire cohort of patients with 1 patient in each arm experiencing a seizure during the follow-up period.

CONCLUSION

The use of prophylactic levetiracetam did not result in significant neurotoxicity or depression when given for either 1 week or 6 weeks. The incidence of seizure after craniotomy for tumor resection is low regardless of duration of therapy.

A randomized, double-blind, double-dummy, multicenter trial comparing the efficacy and safety of extended- and immediate-release levetiracetam in people with partial epilepsy

PURPOSE

The aim of this trial was to compare the efficacy and safety of two formulations of levetiracetam in people with partial epilepsy over a 12-week treatment period.

METHODS

We performed a randomized, paralleled, and multicenter trial that consisted of a 4-week single-blind placebo run-in, followed by a 12-week double-blind, double-dummy treatment phase to compare the efficacy and safety of levetiracetam extended-release (LEV-ER) and immediate-release (LEV-IR) tablets as an adjunctive treatment in adult patients with uncontrolled epilepsy.

RESULTS

The median partial-onset seizure (POS) frequency per week (min-max) was 0.3 (0.0, 17.4; 95% confidence interval [95% CI] 1.3, 4.8) in the LEV-ER group and 0.3 (0.0, 31.4; 95% CI - 0.1, 4.3) in the LEV-IR group. No serious adverse events occurred during the trial period. Both groups had the same responder rate (58.6%), while a higher rate of seizure freedom over the treatment period was noted in the LEV-ER group compared with the LEV-IR group (27.6% vs. 13.8%, respectively). The European Quality of Life-5 Dimensions scores significantly increased in the LEV-ER-treated group, in contrast to the scores in the LEV-IR group, which decreased (7.2 vs. - 1.5, p = 0.03).

CONCLUSION

These results suggest that LEV-ER is equivalent to LEV-IR in reducing the frequency of POS and has a similar tolerability as LEV-IR as an add-on therapy. In addition, LEV-ER treatment improved the health-related quality of life of people with uncontrolled partial epilepsy.

A Clinician's Guide to Oral Extended-Release Drug Delivery Systems in Epilepsy

Epilepsy is one of the most common chronic neurologic disorders that affects individuals of all ages. It is primarily managed with antiepileptic drugs (AEDs), with the goal of maintaining complete seizure control combined with minimal or no adverse effects. Oral administration is the mainstay of AED delivery for patients with chronic epilepsy and consists essentially of immediate-release (IR) and modified-release (delayed-release and extended-release [ER]) dosage formulations. Extended-release formulations (hydrophilic or hydrophobic matrix systems, reservoir systems, and osmotic-release systems) release a drug in a controlled manner during an extended period of time following administration. Extended-release formulations have many advantages compared with IR formulations, including simplification of dosing regimens, reduction in pill burden, and reduction in the peak-to-trough fluctuations in serum drug concentration that may be associated with a decreased risk of adverse effects and of seizures. These advantages have the potential to increase adherence to antiepileptic therapy, improve the quality of life of patients, and reduce health care costs. This article, which is intended as a practical guide for clinicians, reviews the properties of the different ER AED formulations currently available and discusses the advantages of ER over IR formulations. Subsequently, an explanation of the technologic basis of the different oral ER formulations, the critical attributes that differentiate ER products, and their individual strengths and weaknesses is provided. Specific recommendations to practitioners on treating patients with ER formulations are included.

Extended-release drug formulations for the treatment of epilepsy

INTRODUCTION

Extended-release (ER) preparations are either available or have been tested for several antiepileptic drugs (AEDs). Indeed, they may be helpful in improving efficacy, tolerability, adherence, compared to the corresponding immediate release (IR) preparations available. The use of ER preparations has been advocated in women of childbearing age and is - depending on the drug - especially helpful in patients who are treated in combination with enzyme inducing AEDs as well as in children.

AREAS COVERED

Clinical and pharmacokinetic studies on ER formulations of AEDs were identified by a PubMed literature research. Further references were added from the authors' personal knowledge and from the reference lists of the identified studies. Reviews and expert commentaries were included, where necessary.

EXPERT OPINION

Unfortunately, studies providing direct comparisons of ER and IR formulations of a given drug are only available for a handful of drugs. ER preparations are especially helpful in drugs with a short elimination half-life and concentration-depending efficacy and tolerability.

Disposition of Extended Release Levetiracetam in Normal Healthy Dogs After Single Oral Dosing

Background

Levetiracetam is an anticonvulsant used for control of canine epilepsy. An extended release preparation should improve dosing convenience.

Objectives

To determine the disposition of extended release levetiracetam in normal dogs after single dosing.

Animals

Pharmacokinetic study: 16 healthy, adult dogs.

Methods

Using a partially randomized crossover study, levetiracetam (30 mg/kg) was administered intravenously (IV) and orally (PO) as extended release preparation with or without food. Blood was collected for 24 hours (IV) or 36 hours (PO). Serum levetiracetam was quantitated by immunoassay and data were subjected to noncompartmental analysis.

Results

Pharmacokinetic parameters for fasted versus fed animals, respectively, were (mean ± SEM): C_max = 26.6 ± 2.38 and 30.7 ± 2.88 μ/mL, T_max = 204.3 ± 18.9 and 393.8 ± 36.6 minutes, t_1/2 = 4.95 ± 0.55 and 4.48 ± 0.48 hours, MRT = 9.8 ± 0.72 and 10 ± 0.64 hours, MAT = 4.7 ± 0.38 and 5.6 ± 0.67 hours, and F = 1.04 ± 0.04 and 1.26 ± 0.07%. Significant differences were limited to T_max (longer) and F (greater) in fed compared to fasted animals. Serum levetiracetam concentration remained above 5 μ/mL for approximately 20 hours in both fasted and fed animals.

Conclusions and Clinical Importance

Extended release levetiracetam (30 mg/kg q12h), with or without food, should maintain concentrations above the recommended minimum human therapeutic concentration.

Modified-Release Formulations of Second-Generation Antiepileptic Drugs: Pharmacokinetic and Clinical Aspects

Modified-release or extended-release (XR) formulations are used to decrease the frequency of dosing for drugs with rapid elimination, to improve convenience and adherence. Use of a modified-release formulation can decrease the peak to trough fluctuations in serum concentrations and theoretically improve the therapeutic benefit of the drug, by decreasing adverse events associated with the higher peak concentrations. Once-daily formulations of lamotrigine (Lamictal XR(®)), levetiracetam (Keppra XR(®)), oxcarbazepine (Oxtellar XR(®), Apydan(®) extent) and topiramate (Qudexy XR™, Trokendi XR™) are approved for the treatment of focal and/or generalized onset seizures. Other seizure medications have been approved for non-epileptic symptoms. Gabapentin XR (Gralise(®)) is approved for the treatment of post-herpetic neuralgias. Gabapentin enacarbil XR (Horizant(®)) is a prodrug of gabapentin and is indicated for treatment of post-herpetic neuralgia and restless leg syndrome, a novel indication. For all but Qudexy XR™, the tablets/capsules must be swallowed whole, without cutting, crushing or chewing, in order to maintain the XR properties of the formulation. Qudexy XR™ can be swallowed intact or the capsules can be opened and sprinkled onto soft food for those with swallowing difficulties, for example, children and the elderly. The bioavailability of Gralise(®) and Horizant(®) is significantly affected by food, specifically fat content, and should be taken with a meal to maximize absorption. Overall, the primary advantage of the newly released XR formulations is the once-daily dosing to improve convenience and adherence, with very limited data suggesting improved tolerability.

Levetiracetam extended release conversion to monotherapy for the treatment of patients with partial-onset seizures: a double-blind, randomised, multicentre, historical control study

This double-blind, randomised, multicentre, conversion to monotherapy, historical control study (N01280; NCT00419094) evaluated the efficacy, safety and tolerability of levetiracetam extended release (LEV XR) 2000mg/day once daily for the treatment of patients with partial-onset seizures compared with a historical control. Patients aged 12-75 years with 2-40 partial-onset seizures per 4 weeks, taking 1-2 antiepileptic drugs (AEDs) and receiving a stable dosage for ≥4 weeks prior to screening were randomised in a 3:1 ratio to LEV XR 2000 or 1000 mg/day. The study comprised baseline (8 weeks), LEV XR up-titration (2 weeks), baseline AED tapering (6 weeks), LEV XR monotherapy (10 weeks), and entry into open-label follow-up study or down-titration (1 week). The primary efficacy variable was the cumulative exit rate at Day 112 due to predefined exit criteria compared with the historical control. Of the 171 patients randomised to LEV XR 2000 mg/day and 57 randomised to 1000 mg/day, 141 (82.5%) and 50 (87.7%) completed the study. The cumulative exit rate for patients on LEV XR 2000 mg/day (0.375 [95% CI 0.297, 0.453]) was significantly lower than historical control (0.653). Both LEV doses were well tolerated. The most common adverse events during the treatment period were somnolence (21.9%), headache (19.7%) and convulsion (14.9%).

Update on anticonvulsant drugs

In 2009, the US Food and Drug Administration approved three medications for the treatment of epilepsy: rufinamide, lacosamide, and vigabatrin. In addition, extended-release formulations of lamotrigine and levetiracetam were approved recently. When added to the dozen medications for treating epilepsy, the choice is a luxury in terms of additional options, but also a challenge for practitioners to use them all with expertise. Recently, there has been much interest surrounding medications for epilepsy and their possible association with osteoporosis, safety during pregnancy, biological equivalence to generic versions, and possible association with higher rates of suicidality. This review discusses these issues and provides a current overview for the medical management of epilepsy.

Rational Polytherapy with Antiepileptic Drugs

Approximately 30-40% of patients do not achieve seizure control with a single antiepileptic drug (AED). With the advent of multiple AEDs in the past 15 years, rational polytherapy, the goal of finding combinations of AEDs that have favorable characteristics, has become of greater importance. We review the theoretical considerations based on AED mechanism of action, animal models, human studies in this field, and the challenges in finding such optimal combinations. Several case scenarios are presented, illustrating examples of rational polytherapy.