Effect of brivaracetam on cardiac repolarisation--a thorough QT study

Brivaracetam use in clinical practice: a Delphi consensus on its role as first add-on therapy in focal epilepsy and beyond

BACKGROUND

Antiseizure medications remain the cornerstone of treatment for epilepsy, although a proportion of individuals with the condition will continue to experience seizures despite appropriate therapy. Treatment choices for epilepsy are based on variables related to both the individual patient and the available medications. Brivaracetam is a third-generation agent antiseizure medication.

METHODS

We carried out a Delphi consensus exercise to define the role of brivaracetam in clinical practice and to provide guidance about its use as first add-on ASM and in selected clinical scenarios. A total of 15 consensus statements were drafted by an expert panel following review of the literature and all were approved in the first round of voting by panelists. The consensus indicated different clinical scenarios for which brivaracetam can be a good candidate for treatment, including first add-on use.

RESULTS

Overall, brivaracetam was considered to have many advantageous characteristics that render it a suitable option for patients with focal epilepsy, including a fast onset of action, favorable pharmacokinetic profile with few drug-drug interactions, broad-spectrum activity, and being well tolerated across a range of doses. Brivaracetam is also associated with sustained clinical response and good tolerability in the long term.

CONCLUSIONS

These characteristics also make it suitable as an early add-on for the elderly and for patients with post-stroke epilepsy or status epilepticus as highlighted by the present Delphi consensus.

Cardiac adverse effects of antiseizure medications

INTRODUCTION

Patients with severe epilepsy are at increased risk of cardiovascular disease and arrhythmias. Although antiseizure medications (ASMs) may have indirect protective effects against cardiovascular events by reducing seizure frequency and hence sudden death in epilepsy, some of them exert cardiotoxic effects.

AREAS COVERED

Patients with epilepsy, mainly those with severe forms, are at higher risk of cardiac disease because their heart can have structural alterations and electrical instability as a consequence of repeated seizures. Some ASMs have direct protective effects through anti-inflammatory, antioxidant, hypotensive, and lipid-reducing properties. Antiseizure medications can also have toxic cardiac effects including both long-term consequences, such as the increased risk of atherogenesis and subsequent cardiovascular disease due to the influence on lipid profile and pro-inflammatory milieu, and immediate effects as the increased risk of potentially fatal arrhythmias due to the influence on ion channels. Sodium channel blocking ASMs may also affect cardiac sodium channels and this effect is particularly observed in subjects with genetic mutations in cardiac ion channels. Fenfluramine cause valvulopathies in obese subjects and this effect need to be evaluated in epilepsy patients.

EXPERT OPINION

For the selection of treatment, cardiotoxic effects of ASMs should be considered; cardiac monitoring of treatment is advisable.

Brivaracetam for the treatment of focal-onset seizures: pharmacokinetic and pharmacodynamic evaluations

INTRODUCTION

The goal of pharmacologic therapy with antiseizure medications (ASMs) is to achieve a seizure-free state with minimal side effects. About one third of patients treated with available ASMs continue to experience uncontrolled seizures. There is still need for new ASMs with enhanced effectiveness and tolerability.

AREAS COVERED

The present manuscript is based on an extensive Internet and PubMed search from 1999 to 2020. It is focused on the clinical and pharmacological properties of brivaracetam (BRV) in the treatment of epilepsy.

EXPERT OPINION

BRV is approved as add-on or monotherapy (in US) for the treatment of focal-onset seizures with or without secondary generalization. BRV is a high affinity synaptic vesicle glycoprotein 2A ligand, with 15-30-fold higher affinity than levetiracetam. The selectivity of BRV may be associated with fewer clinical adverse effects. BRV shares many of the pharmacokinetic characteristics of an ideal ASMs. Additionally, BRV has a low potential for clinically relevant drug-drug interactions. Its pharmacokinetic profile makes BRV a promising agent for the treatment of status epilepticus (SE). Although BRV is not approved for the treatment of SE, it has demonstrated promising preliminary results. Further studies are needed to explore the efficacy and tolerability of BRV in SE.

Safety and tolerability of adjunctive brivaracetam in epilepsy: In-depth pooled analysis

OBJECTIVE

The objective of this analysis was to provide a comprehensive analysis of safety data for adjunctive brivaracetam (BRV), an antiepileptic drug (AED) of the racetam class, for treatment of focal seizures in patients with epilepsy.

METHODS

Data were pooled from two phase II, placebo-controlled, double-blind, dose-ranging trials (N01114 [ClinicalTrials.gov: NCT00175929], N01193 [NCT00175825]) and three phase III, placebo-controlled, double-blind, 12-week trials (N01252 [NCT00490035], N01253 [NCT00464269], and N01358 [NCT01261325]) in patients aged ≥16 years with focal seizures, as well as a phase III, placebo-controlled, double-blind, 16-week trial in patients aged ≥16 years with focal or generalized epilepsy (N01254 [NCT00504881]). Data are presented for the approved therapeutic dose range of 50-200 mg/day. Data for BRV administered intravenously (25-150 mg doses) were pooled separately from one phase III trial (N01258 NCT01405508]) and two clinical pharmacology trials (N01256 [Part B] [UCB Pharma, data on file]; EP0007 [NCT01796899]). Adverse events (AEs) of interest were summarized in relevant categories.

RESULTS

The safety pool comprised 1957 patients: 1271 receiving adjunctive BRV and 686 receiving placebo. Overall, the incidence of treatment-emergent adverse events (TEAEs) was 66.9% with BRV versus 62.8% with placebo. The most frequently reported TEAEs with BRV (≥5% of patients) versus placebo were somnolence (13.3% vs. 7.9%), headache (10.5% vs. 11.5%), dizziness (10.0% vs. 7.0%), and fatigue (8.2% vs. 4.2%). Incidence of psychiatric disorder-related TEAEs was 11.3% with BRV versus 8.2% with placebo. Behavioral disorder-related TEAE incidence was low (4.0% with BRV vs. 2.5% with placebo). Irritability was reported in 2.7% of BRV-treated patients vs. 1.5% of patients receiving placebo; anger, aggression, and agitation were each reported by ≤1% of patients receiving BRV. Treatment-emergent adverse events potentially associated with psychosis were psychotic disorder (three patients on BRV vs. two patients on placebo), auditory hallucination, illusion, visual hallucination (one patient each on BRV), epileptic psychosis, and hallucination (one patient each on placebo). No additional safety concerns were identified in patients with intravenous (IV) BRV administration (n = 104).

CONCLUSIONS

These safety data for adjunctive BRV support its acceptable safety and tolerability profile.

Evaluation of brivaracetam: a new drug to treat epilepsy

INTRODUCTION

High prevalence of therapy-resistant epilepsy demands development of anticonvulsants with new mechanisms of action. Brivaracetam is an analogue of levetiracetam which binds to the synaptic vesicle protein 2A (SV2A) and decreases release of excitatory neurotransmitters. Areas covered: Relevant published studies were searched for by predefined strategy in MEDLINE, EBSCO and SCINDEKS electronic databases. Brivaracetam is effective as adjunctive therapy for uncontrolled partial-onset seizures with or without secondary generalization in patients 16 years and older with epilepsy. It reduces baseline-adjusted focal seizure frequency per week from 7.3 to 12.8% over placebo. Adverse events rate in patients with brivaracetam is not higher than in patients with placebo. Expert opinion: Brivaracetam is an important step forward in the treatment of therapy-resistant partial-onset seizures with or without secondary generalization. Its development was systematic and targeted. Due to its efficacy and excellent safety profile, it is likely that brivaracetam will be often prescribed. In future, efficacy and safety of brivaracetam should be tested in monotherapy settings and also in the first-line therapy of partial-onset seizures.

Postmarketing experience with brivaracetam in the treatment of epilepsies: A multicenter cohort study from Germany

OBJECTIVE

To evaluate factors predicting efficacy, retention, and tolerability of add-on brivaracetam (BRV) in clinical practice.

METHODS

A multicenter, retrospective cohort study recruiting all patients who started BRV between February and November 2016 with observation time between 3 and 12 months.

RESULTS

Of a total of 262 patients (mean age 40, range 5-81 years, 129 male) treated with BRV, 227 (87%) were diagnosed to have focal, 19 (7%) idiopathic generalized and 8 (3%) symptomatic generalized epilepsy, whereas 8 (3%) were unclassified. The length of exposure to BRV ranged from 1 day to 12 months, with a median retention time of 6.1 months, resulting in a total exposure time to BRV of 1,504 months. The retention rate was 79.4% at 3 months and 75.8% at 6 months. Efficacy at 3 months was 41.2% (50% responder rate) with 14.9% seizure-free for 3 months and, at 6 months, 40.5% with 15.3% seizure-free. Treatment-emergent adverse events were observed in 37.8% of the patients, with the most common being somnolence, dizziness, and behavioral adverse events (BAEs). BAE that presented under previous levetiracetam (LEV) treatment improved upon switch to BRV in 57.1% (20/35) and LEV-induced somnolence improved in 70.8% (17/24). Patients with BAE on LEV were more likely to develop BAE on BRV (odds ratio [OR] 3.48, 95% confidence interval [CI] 1.53-7.95).

SIGNIFICANCE

BRV in broad clinical postmarketing use is a well-tolerated anticonvulsant drug with 50% responder rates, similar to those observed in the regulatory trials, even though 90% of the patients included had previously been exposed to LEV. An immediate switch from LEV to BRV at a ratio of 10:1 to 15:1 is feasible. The only independent significant predictor of efficacy was the start of BRV in patients not currently taking LEV. The occurrence of BAE during previous LEV exposure predicted poor psychobehavioral tolerability of BRV treatment. A switch to BRV can be considered in patients with LEV-induced BAE.

Brivaracetam as adjunctive therapy for the treatment of partial-onset seizures in patients with epilepsy: the current evidence base

Brivaracetam (BRV) is a novel antiepileptic drug recently licensed for the treatment of partial epilepsy in adults and adolescents over 16 years old. Like levetiracetam (LEV), it is a ligand of the synaptic vesicle protein SV2A. BRV has been shown in animal models and in studies using human brain slices to have a higher SV2A affinity and faster penetration into the brain. Its efficacy and safety have been shown in several randomized, controlled studies. The recommended initial dose is 50-100 mg, divided into two daily doses. Up-titration to a 200 mg daily dose is possible. Dizziness and somnolence are frequent side effects. There are some hints that BRV may be less frequently associated with behavioural adverse events than LEV. Long-term efficacy and safety and BRV use in special patient groups have to be assessed in the future.

Brivaracetam: A Review in Partial-Onset (Focal) Seizures in Patients with Epilepsy

Brivaracetam (Briviact(®); BRIVLERA™) is a high affinity synaptic vesicle protein 2A (SV2A) ligand available orally (as a tablet or solution) or intravenously (as a bolus or infusion) in various countries worldwide, including the USA, Canada and those of the EU. It is approved as adjunctive therapy for the treatment of partial-onset seizures (POS) in adults (aged ≥18 years) [USA, EU and Canada] and adolescents (aged 16 to <18 years) [USA and EU] with epilepsy. In multinational, phase III studies in adults and adolescents (aged ≥16 years), oral brivaracetam as adjunctive therapy to other antiepileptic drugs (AEDs) was generally associated with significant median percent reductions over placebo in seizure frequency and significant improvements in the proportion of patients achieving a ≥50 % reduction in seizure frequency compared with placebo. These benefits appeared to be sustained during up to 96 months' therapy in follow-up studies. Whether administered orally or intravenously, adjunctive brivaracetam was generally well tolerated in clinical studies, with the majority of treatment-emergent adverse events (TEAEs) being mild or moderate in intensity. In the absence of head-to-head studies, definitive conclusions on the comparative efficacy and tolerability of brivaracetam versus newer AEDs are not yet possible. In the meantime, brivaracetam extends the options currently available for the treatment of POS in patients aged ≥16 years with epilepsy.

Safety and tolerability of adjunctive brivaracetam as intravenous infusion or bolus in patients with epilepsy

OBJECTIVES

An intravenous (IV) formulation of brivaracetam (BRV), a selective, high-affinity ligand for synaptic vesicle protein 2A, has been developed. We investigated the safety, tolerability, and pharmacokinetics of adjunctive IV BRV administered as a bolus or infusion to adults with epilepsy.

METHODS

A phase III, multicenter, randomized, four-arm, parallel-group study (NCT01405508) of patients aged 16-70 years with focal or generalized epilepsy uncontrolled by 1-2 antiepileptic drugs was undertaken. The study comprised a 7-day baseline period, a 7-day double-blind run-in period (oral BRV 200 mg/day or placebo [PBO] twice daily [BID]), and 4.5-day open-label evaluation period (IV BRV 200 mg/day BID; 2-min bolus or 15-min infusion, total nine doses). Patients were randomized 1:1:1:1 PBO/BRV bolus; PBO/BRV infusion; BRV/BRV bolus; BRV/BRV infusion. Safety and tolerability were assessed using adverse events, electrocardiography, vital signs, and laboratory assessments. BRV plasma concentrations were measured before and 15 min after the first and last IV doses.

RESULTS

Of the 105 patients randomized (53.3% women; 77.1% white; mean [standard deviation; SD] age 41.6 [12.2] years), 103 (98.1%) completed the study. Treatment-emergent adverse event (TEAE) incidence during IV BRV was similar whether IV BRV was initiated first (70.6%) or followed oral BRV (66.0%), and whether it was administered as a bolus (71.2%) or infusion (65.4%). Injection-related TEAEs were reported by 9.6% of patients following bolus and 11.5% following infusion. No serious TEAEs were reported. IV BRV plasma concentrations were higher after the first dose in the conversion groups than initiation groups, and slightly higher in the bolus arm than the infusion arm; concentrations were similar in all patients after the last IV dose.

SIGNIFICANCE

IV BRV was generally well tolerated, with similar tolerability as a bolus or infusion and independent of de novo administration or as conversion from oral BRV tablets. IV BRV may be an option for patients who are unable to receive oral BRV.

Emerging drugs for partial-onset epilepsy: a review of brivaracetam

There are more than 12 new antiepileptic drugs approved in the last 2 decades. Even with these newer agents, seizure remission is still unachievable in around 30% of patients with partial-onset seizures (POS). Brivaracetam (BRV) is chemically related to levetiracetam (LEV) and possesses a strong binding affinity for the synaptic vesicle protein 2A tenfold above that of LEV, and other possible modes of antiepileptic actions. BRV is now under Phase III development for POS, but data from one Phase III trial also suggested its potential efficacy for primary generalized seizures. The purpose of this review is to provide updated information on the mechanisms of action of the available antiepileptic drugs, with a focus on BRV to assess its pharmacology, pharmacokinetics, clinical efficacy, safety, and tolerability in patients with uncontrolled POS. To date, six Phase IIb and III clinical trials have been performed to investigate the efficacy, safety, and tolerability of BRV as an adjunctive treatment for patients with POS. Generally, BRV was well tolerated and did not show significant difference in safety profile, compared to placebo. The efficacy outcomes of BRV, although not consistent across trials, did indicate that BRV was a promising add-on therapy for patients with POS. In conclusion, the many favorable attributes of BRV, like its high oral efficacy, good tolerability, dosing regimen, and minimal drug interaction, make it a promising antiepileptic therapy for patients with uncontrolled partial-onset epilepsy.

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.

Brivaracetam for the treatment of epilepsy

INTRODUCTION

Approximately one third of patients with epilepsy fail to respond to existing medications. Levetiracetam is an effective antiepileptic drug (AED) postulated to act by binding to synaptic vesicle protein 2A. Brivaracetam is a novel high affinity SV2A ligand with approximately 20-fold higher affinity for SV2A protein than levetiracetam. It is at an advanced stage of clinical development for treatment of epilepsy.

AREAS COVERED

This article reviews animal data, pharmacokinetics, and phase 1-3 data of Brivaracetam treatment of epilepsy. Brivaracetam has broad-spectrum anticonvulsant activity in animal models.

EXPERT OPINION

Phase 1 studies indicated that single oral doses of 5-800 mg and repeated oral doses of up to 600 mg were well tolerated and showed favorable pharmacokinetic profile. Phase 2 studies indicated good safety and tolerability of brivaracetam in the dose range of 5-150 mg/day and provided proof of concept for efficacy in treating refractory partial onset seizures. Efficacy and safety have been evaluated in 4 phase 3 studies with dose range of 5-200 mg which have demonstrated efficacy in the range of 100-200 mg/day dose and, in most studies, also with 50 mg/day dose, and good safety and tolerability profile across 5-200 mg doses in adjunctive treatment of refractory partial onset seizures.

Brivaracetam: review of its pharmacology and potential use as adjunctive therapy in patients with partial onset seizures

Brivaracetam (BRV), a high-affinity synaptic vesicle protein 2A ligand, reported to be 10–30-fold more potent than levetiracetam (LEV), is highly effective in a wide range of experimental models of focal and generalized seizures. BRV and LEV similarly bind to synaptic vesicle protein 2A, while differentiating for other pharmacological effects; in fact, BRV does not inhibit high voltage Ca²⁺ channels and AMPA receptors as LEV. Furthermore, BRV apparently exhibits inhibitory activity on neuronal voltage-gated sodium channels playing a role as a partial antagonist. BRV is currently waiting for approval both in the United States and the European Union as adjunctive therapy for patients with partial seizures. In patients with photosensitive epilepsy, BRV showed a dose-dependent effect in suppressing or attenuating the photoparoxysmal response. In well-controlled trials conducted to date, adjunctive BRV demonstrated efficacy and good tolerability in patients with focal epilepsy. BRV has a linear pharmacokinetic profile. BRV is extensively metabolized and excreted by urine (only 8%–11% unchanged). The metabolites of BRV are inactive, and hydrolysis of the acetamide group is the mainly involved metabolic pathway; hepatic impairment probably requires dose adjustment. BRV does not seem to influence other antiepileptic drug plasma levels. Six clinical trials have so far been completed indicating that BRV is effective in controlling seizures when used at doses between 50 and 200 mg/d. The drug is generally well-tolerated with only mild-to-moderate side effects; this is confirmed by the low discontinuation rate observed in these clinical studies. The most common side effects are related to central nervous system and include fatigue, dizziness, and somnolence; these apparently disappear during treatment. In this review, we analyzed BRV, focusing on the current evidences from experimental animal models to clinical studies with particular interest on potential use in clinical practice. Finally, pharmacological properties of BRV are summarized with a description of its pharmacokinetics, safety, and potential/known drug–drug interactions.

Profile of brivaracetam and its potential in the treatment of epilepsy

Brivaracetam (BRV) (UCB 34714) is currently under review by the US Food and Drug Administration and European Medicines Agency for approval as an add-on treatment for adult patients with partial seizures. Similar to levetiracetam (LEV), BRV acts as a high-affinity ligand of the synaptic vesicle protein 2A, however, it has been shown to be 10- to 30-fold more potent than LEV. Moreover, BRV does not share the LEV inhibitory activity on the high voltage Ca(2+) channels and AMPA receptors, and it has been reported to act as a partial antagonist on neuronal voltage-gated sodium channels. The pharmacokinetic profile of BRV is favorable and linear, and it undergoes an extensive metabolism into inactive compounds, mainly through the hydrolysis of its acetamide group. Furthermore, it does not significantly interact with other antiepileptic drugs and more than 95% is excreted through the urine, with an unchanged fraction of 8%-11%. BRV has a half-life of approximately 8-9 hours and it is usually given twice daily. To date, a wide range of experimental studies have reported the effectiveness of BRV with regards to partial and generalized seizures. In humans, six randomized, placebo-controlled trials and two meta-analyses highlighted the efficacy, or good tolerability, of BRV as an add-on treatment for patients with uncontrolled partial seizures. A wide dose range of BRV has been evaluated in those trials (5-200 mg), but the most suitable for clinical use appears to be 50-100 mg/day. The most common adverse reactions to BRV are mild to moderate, transient, often improve during the course of the treatment, and mainly consist of central nervous system symptoms, such as fatigue, dizziness, and somnolence. The aim of this paper is to critically review the literature data regarding experimental animal models and clinical trials on BRV, and to define its potential usefulness for the clinicians who manage patients with epilepsy.

Brivaracetam for the treatment of epilepsy in adults

Brivaracetam (BRV) is a new antiepileptic drug structurally related to levetiracetam but with a 15 to 30-fold increased affinity for the same molecular target, namely the SV2A ligand. BRV is currently under Phase III development as adjunctive treatment for partial onset seizures but data from some Phase III suggest also potential efficacy for primary generalized seizures. Although two studies are negative for the primary efficacy endpoint, global results seem to suggest a wide spectrum of efficacy for both partial onset and primary generalized seizures and a favourable safety and pharmacokinetic profile. This article is aimed at providing a comprehensive overview of current evidence about BRV in the treatment of epilepsy taking into account emerging concerns regarding clinical trials in epilepsy.

Comparison of two methods of estimating reader variability in QT interval measurements in thorough QT/QTc studies

BACKGROUND

Two methods of estimating reader variability (RV) in QT measurements between 12 readers were compared.

METHODS

Using data from 500 electrocardiograms (ECGs) analyzed twice by 12 readers, we bootstrapped 1000 datasets each for both methods. In grouped analysis design (GAD), the same 40 ECGs were read twice by all readers. In pairwise analysis design (PAD), 40 ECGs analyzed by each reader in a clinical trial were reanalyzed by the same reader (intra-RV) and also by another reader (inter-RV); thus, variability between each pair of readers was estimated using different ECGs.

RESULTS

Inter-RV (mean [95% CI]) between pairs of readers by GAD and PAD was 3.9 ms (2.1-5.5 ms) and 4.1 ms (2.6-5.4 ms), respectively, using ANOVA, 0 ms (-0.0 to 0.4 ms), and 0 ms (-0.7 to 0.6 ms), respectively, by actual difference between readers and 7.7 ms (6.2-9.8 ms) and 7.7 ms (6.6-9.1 ms), respectively, by absolute difference between readers. Intra-RV too was comparable.

CONCLUSIONS

RV estimates by the grouped- and pairwise analysis designs are comparable.

Design and analysis considerations for thorough QT studies employing conventional (10 s, 12-lead) ECG recordings

The QT interval from the ECG cannot be measured precisely. The relationship of the QT interval to the RR interval within individuals across time and different RR values, and across individuals eludes complete understanding. Intrinsic beat-to-beat variability in QT interval corrected for heart rate (QTc interval) is not trivial. Therefore, it is difficult to determine a valid and reliable estimate of the time for ventricular repolarization based on the QTc interval. Yet, it must be demonstrated that a drug does not result in an increase in the QTc interval that exceeds 5 ms with some reasonable degree of certainty to be quite confident that the drug does not convey some risk of ventricular tachydysrhythmia due to delayed ventricular repolarization. This demonstration can be a Herculean task due to the magnitude of variability in the QTc interval. Design features and analytical methods that might be used in the thorough QT study to improve the chances of demonstrating the true relationship between a drug and QTc interval are reviewed.

Choice of an alternative lead for QT interval measurement in serial ECGs when Lead II is not suitable for analysis

INTRODUCTION

Conventionally, QT interval is measured in lead II. There are no data to select an alternative lead for QT measurement when it cannot be measured in Lead II for any reason.

METHODS AND RESULTS

We retrospectively analyzed ECGs from 1906 healthy volunteers from 41 phase I studies. QT interval was measured on the median beat in all 12 leads. The mean difference in QT interval between lead aVR and in Lead II was the least, followed by aVF, V5, V6 and V4; lead aVL had maximum difference. The T wave was flat (<0.1 mV) in Lead II in 6.9% of ECGs; it was also flat in 20% of these ECGs (1.4% of all ECGs) in Leads aVR, aVF and V5.

CONCLUSIONS

When QT interval cannot be measured in Lead II, the best alternative leads are aVR, aVF, V5, V6 and V4 in that sequence. It differs maximally from that in Lead II in Lead aVL.

Highly automated QT measurement techniques in 7 thorough QT studies implemented under ICH E14 guidelines

Thorough QT (TQT) studies are designed to evaluate potential effect of a novel drug on the ventricular repolarization process of the heart using QTc prolongation as a surrogate marker for torsades de pointes. The current process to measure the QT intervals from the thousands of electrocardiograms is lengthy and expensive. In this study, we propose a validation of a highly automatic-QT interval measurement (HA-QT) method. We applied a HA-QT method to the data from 7 TQT studies. We investigated both the placebo and baseline-adjusted QTc interval prolongation induced by moxifloxacin (positive control drug) at the time of expected peak concentration. The comparative analysis evaluated the time course of moxifloxacin-induced QTc prolongation in one study as well. The absolute HA-QT data were longer than the FDA-approved QTc data. This trend was not different between ECGs from the moxifloxacin and placebo arms: 9.6 ± 24 ms on drug and 9.8 ± 25 ms on placebo. The difference between methods vanished when comparing the placebo-baseline-adjusted QTc prolongation (1.4 ± 2.8 ms, P = 0.4). The differences in precision between the HA-QT and the FDA-approved measurements were not statistically different from zero: 0.1 ± 0.1 ms (P = 0.7). Also, the time course of the moxifloxacin-induced QTc prolongation adjusted for placebo was not statistically different between measurements methods.

The thorough QT/QTc study 4 years after the implementation of the ICH E14 guidance

The ICH E14 guidance on how to clinically assess a new drug's liability to prolong the QT interval was adopted in May 2005. A centre-piece of the guidance was the establishment of one single trial, the 'thorough QT/QTc study', intended to confidently identify drugs that may cause QT prolongation. Initially perceived as a great challenge, this study has rapidly become a standard component of all clinical development programs for new molecular entities. The study is normally conducted in healthy volunteers, includes both a positive and a negative (placebo) control and is stringently powered to exclude an effect on the QTc interval exceeding 10 ms. The E14 guidance was intentionally not very prescriptive and allowed sponsors and service providers to explore new methodologies. This has allowed for a rapid development of new methods during the first years after the guidance's implementation, such as computer-assisted algorithms for QT measurements. Regulators have worked in close collaboration with pharmaceutical industry to set standards for the design and conduct of the 'thorough QT/QTc study', which therefore has evolved as a key component of cardiac safety assessment of new drugs. This paper summarizes the requirements on the 'thorough QT/QTc study' with emphasis on the standard that has evolved based on interactions between regulators and sponsors and the experience from a large number of completed studies.

A single supratherapeutic dose of vorinostat does not prolong the QTc interval in patients with advanced cancer

PURPOSE

This dedicated QTc phase I study, conducted in advanced-stage cancer patients, assessed the effect of a single supratherapeutic dose (800 mg) of vorinostat on the QTc interval.

EXPERIMENTAL DESIGN

A randomized, partially blind, placebo-controlled, two-period, crossover study was conducted. Patients (n = 25) received single doses of 800 mg vorinostat and placebo in the fasted state. Holter electrocardiogram monitoring was done before each treatment and for 24 h postdose. Blood samples for vorinostat concentration were collected through 24 h postdose following vorinostat treatment only. Prescribed electrocardiogram and blood sampling times were designed to capture the expected C(max) of vorinostat.

RESULTS

Twenty-four of the 25 patients enrolled in the study were included in the QTc analysis. The upper bound of the two-sided 90% confidence interval for the QTcF interval for the placebo-adjusted mean change from baseline of vorinostat was <10 ms at every time point. No patient had a QTcF change from baseline value >30 ms. One patient had QTcF values >450 ms (seen after both vorinostat and placebo administration) and none had values >480 ms. Mean AUC(0-infinity) and C(max) values attained were on the order of approximately 1.93- and approximately 1.41-fold higher, respectively, compared with the 400 mg clinical dose. Based on assessment of clinical and laboratory adverse experiences, single doses of 800 mg vorinostat were generally well tolerated.

CONCLUSIONS

Administration of a single supratherapeutic dose of the histone deacetylase inhibitor vorinostat is not associated with prolongation of the QTc interval. A dedicated QTc study in advanced cancer patients is a robust means for assessing risk for ventricular repolarization prolongation.

Update on the evaluation of a new drug for effects on cardiac repolarization in humans: issues in early drug development

Following reports of death from cardiac arrhythmias with drugs like terfenadine and cisapride, the International Conference for Harmonization formulated a guidance (E14) document. This specifies that all new drugs must undergo a 'thorough QT/QTc' (TQT) study to detect drug-induced QT prolongation, a surrogate marker of ventricular tachycardia, especially torsades de pointes (TdPs). With better understanding of data from several completed TQT studies, regulatory requirements have undergone some changes since the E14 guidance was implemented in October 2005. This article reviews the implications of the E14 guidance and the changes in its interpretation including choice of baseline QT, demonstration of assay sensitivity, statistical analysis of the effect of new drug and positive control, and PK-PD modelling. Some issues like use of automated QT measurements remain unresolved. Pharmaceutical companies too are modifying Phase 1 studies to detect QTc liability early in order to save time and resources. After the E14 guidance, development of several drugs that prolong QTc by >5 ms is being abandoned by sponsors. However, all drugs that prolong the QT interval do not increase risk of TdP. Researchers in regulatory agencies, academia and industry are working to find better biomarkers of drug-induced TdP which could prevent many useful drugs from being prematurely abandoned. Drug-induced TdP is a rare occurrence. With fewer drugs that prolong QT interval reaching the licensing stage, knowing which of these drugs are torsadogenic is proving to be elusive. Thus, paradoxically, the effectiveness of the E14 guidance itself has made prospective validation of new biomarkers difficult.

Progress report on new antiepileptic drugs: a summary of the Ninth Eilat Conference (EILAT IX)

The Ninth Eilat Conference on New Antiepileptic Drugs (AEDs)-EILAT IX, took place in Sitges, Barcelona from the 15th to 19th of June 2008. Over 300 basic scientists, clinical pharmacologists and neurologists from 25 countries attended the conference, whose main themes included old and new AEDs in generalized epilepsies, novel formulations and routes of administration of AEDs, common targets and mechanisms of action of drugs for treating epilepsy and other central nervous system (CNS) disorders, and opportunities and perspectives in new AED discovery. Consistent with previous formats of this conference, a large part of the programme was devoted to a review of AEDs in development, as well as updates on AEDs introduced since 1989. Unlike previous EILAT manuscripts, the current (EILAT IX) manuscript focuses only on the preclinical and clinical pharmacology of AEDs that are currently in development. These include brivaracetam, carisbamate (RWJ-333369), 2-deoxy-d-glucose, eslicarbazepine acetate (BIA-2-093), ganaxolone, huperzine, JZP-4, lacosamide, NAX-5055, propylisopropylacetamide (PID), retigabine, T-2000, tonabersat, valrocemide and YKP-3089. The CNS efficacy of these compounds in anticonvulsant animal models as well as other disease model systems are presented in first and second tables and their proposed mechanisms of action are summarized in the third table.