Difficulties in extrapolating from clinical trial data to clinical practice: the case of antiepileptic drugs

Adjunctive cenobamate in people with focal onset seizures: Insights from the Italian Expanded Access Program

OBJECTIVE

This study was undertaken to assess the effectiveness/tolerability of adjunctive cenobamate, variations in the load of concomitant antiseizure medications (ASMs) and predictors of clinical response in people with focal epilepsy.

METHODS

This was a retrospective study at 21 centers participating in the Italian Expanded Access Program. Effectiveness outcomes included retention and responder rates (≥50% and 100% reduction in baseline seizure frequency). Tolerability/safety outcomes included the rate of treatment discontinuation due to adverse events (AEs) and their incidence. Total drug load was quantified as the number of concomitant ASMs and total defined daily dose (DDD). Concomitant ASMs were also classified according to their mechanism of action and pharmacokinetic interactions to perform explorative subgroup analyses.

RESULTS

A total of 236 subjects with a median age of 38 (Q1-Q3 = 27-49) years were included. At 12 months, cenobamate retention rate was 78.8% and responders were 57.5%. The seizure freedom rates during the preceding 3 months were 9.8%, 12.2%, 16.3%, and 14.0% at 3, 6, 9, and 12 months. A higher percentage of responders was observed among subjects treated with clobazam, although the difference was not statistically significant. A total of 223 AEs were recorded in 133 of 236 participants, leading to cenobamate discontinuation in 8.5% cases. At 12 months, a reduction of one or two concomitant ASMs occurred in 42.6% and 4.3% of the subjects. The median total DDD of all concomitant ASMs decreased from 3.34 (Q1-Q3 = 2.50-4.47) at baseline to 2.50 (Q1-Q3 = 1.67-3.50) at 12 months (p < .001, median percentage reduction = 22.2%). The highest rates of cotreatment withdrawal and reductions in the DDD were observed for sodium channel blockers and γ-aminobutyric acidergic modulators (above all for those linked to pharmacokinetic interactions), and perampanel.

SIGNIFICANCE

Adjunctive cenobamate was associated with a reduction in seizure frequency and in the burden of concomitant ASMs in adults with difficult-to-treat focal epilepsy. The type of ASM associated did not influence effectiveness except for a favorable trend with clobazam.

Gabapentin monotherapy for epilepsy: A review

BACKGROUND

Epilepsy is one of the most common chronic neurological disorders, affecting more than 50 million people globally. In this review we summarised the evidence from randomised controlled trials of gabapentin used as monotherapy for the treatment of focal epilepsy, both newly diagnosed and drug-resistant, with or without secondary generalisation.

OBJECTIVE

To assess the effects of gabapentin monotherapy for people with epileptic focal seizures with and without secondary generalisation.

METHODS

We searched the Cochrane Register of Studies (CRS Web) and MEDLINE (Ovid, 1946 to 24 February 2020) on 25 February 2020. CRS Web includes randomised or quasi-randomised controlled trials from PubMed, Embase, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform, the Cochrane Central Register of Controlled Trials (CENTRA), and the specialised registers of Cochrane Review Groups including the Cochrane Epilepsy Group. We also searched several Russian databases, reference lists of relevant studies, ongoing trials registers, conference proceedings, and we contacted trial authors.

RESULTS

We found five randomised controlled trials (3167 participants) comparing gabapentin to other antiepileptic drugs (AEDs) and differing doses of gabapentin as monotherapy for newly diagnosed focal epilepsy and drug- resistant focal epilepsy with or without secondary generalisation. Two review authors independently applied the inclusion criteria, assessed trial quality, risk of bias, and extracted data. We used the GRADE approach to assess the certainty of evidence and present seven patient-important outcomes in the "Summary of findings" tables. The quality of evidence was very low to moderate due to poor reporting quality, poor trial design, and other risks of bias, such as selective presentation of findings and potential heavy industry input. Better quality research may change our certainty in the effect estimates. None of the included trials reported on the number of people with 50% or greater reduction in seizures and time to withdrawal (retention time) in an extractable way. Gabapentin-treated participants were more likely to withdraw from treatment for any cause (285/539) than those treated with lamotrigine, oxcarbazepine, or topiramate pooled together (695/1317) (RR 1.13, 95% CI 1.02 to 1.25; 3 studies, 1856 participants; moderate-certainty evidence), but not carbamazepine. Fewer people treated with gabapentin withdrew from treatment owing to adverse events (190/525) than those treated with carbamazepine, oxcarbazepine, or topiramate (479/1238), (RR 0.79, 95% CI 0.69 to 0.91; 1763 participants, 3 studies; moderate-certainty evidence), but not lamotrigine.

CONCLUSION

Gabapentin as monotherapy probably controlled seizures no better and no worse than comparator AEDs (lamotrigine, carbamazepine, oxcarbazepine, and topiramate). Compared to carbamazepine, gabapentin was probably better in retaining people in studies and preventing withdrawals due to adverse events. The most common side effects associated with gabapentin were ataxia (poor co-ordination and unsteady gait), dizziness, fatigue, and drowsiness.

Patient-reported outcomes via electronic health record portal versus telephone: a pragmatic randomized pilot trial of anxiety or depression symptoms in epilepsy

Objective

To close gaps between research and clinical practice, tools are needed for efficient pragmatic trial recruitment and patient-reported outcome collection. The objective was to assess feasibility and process measures for patient-reported outcome collection in a randomized trial comparing electronic health record (EHR) patient portal questionnaires to telephone interview among adults with epilepsy and anxiety or depression symptoms.

Materials and Methods

Recruitment for the randomized trial began at an epilepsy clinic visit, with EHR-embedded validated anxiety and depression instruments, followed by automated EHR-based research screening consent and eligibility assessment. Fully eligible individuals later completed telephone consent, enrollment, and randomization. Participants were randomized 1:1 to EHR portal versus telephone outcome assessment, and patient-reported and process outcomes were collected at 3 and 6 months, with primary outcome 6-month retention in EHR arm (feasibility target: ≥11 participants retained).

Results

Participants (N = 30) were 60% women, 77% White/non-Hispanic, with mean age 42.5 years. Among 15 individuals randomized to EHR portal, 10 (67%, CI 41.7%-84.8%) met the 6-month retention endpoint, versus 100% (CI 79.6%-100%) in the telephone group (P = 0.04). EHR outcome collection at 6 months required 11.8 min less research staff time per participant than telephone (5.9, CI 3.3-7.7 vs 17.7, CI 14.1-20.2). Subsequent telephone contact after unsuccessful EHR attempts enabled near complete data collection and still saved staff time.

Discussion

In this randomized study, EHR portal outcome assessment did not meet the retention feasibility target, but EHR method saved research staff time compared to telephone.

Conclusion

While EHR portal outcome assessment was not feasible, hybrid EHR/telephone method was feasible and saved staff time.

Long-term efficacy, tolerability, and retention of brivaracetam in epilepsy treatment: A longitudinal multicenter study with up to 5 years of follow-up

OBJECTIVE

This study was undertaken to evaluate the long-term efficacy, retention, and tolerability of add-on brivaracetam (BRV) in clinical practice.

METHODS

A multicenter, retrospective cohort study recruited all patients who initiated BRV between February and November 2016, with observation until February 2021.

RESULTS

Long-term data for 262 patients (mean age = 40 years, range = 5-81 years, 129 men) were analyzed, including 227 (87%) diagnosed with focal epilepsy, 19 (7%) with genetic generalized epilepsy, and 16 (6%) with other or unclassified epilepsy syndromes. Only 26 (10%) patients had never received levetiracetam (LEV), whereas 133 (50.8%) were switched from LEV. The length of BRV exposure ranged from 1 day to 5 years, with a median retention time of 1.6 years, resulting in a total BRV exposure time of 6829 months (569 years). The retention rate was 61.1% at 12 months, with a reported efficacy of 33.1% (79/239; 50% responder rate, 23 patients lost-to-follow-up), including 10.9% reported as seizure-free. The retention rate for the entire study period was 50.8%, and at last follow-up, 133 patients were receiving BRV at a mean dose of 222 ± 104 mg (median = 200, range = 25-400), including 52 (39.1%) who exceeded the recommended upper dose of 200 mg. Fewer concomitant antiseizure medications and switching from LEV to BRV correlated with better short-term responses, but no investigated parameters correlated with positive long-term outcomes. BRV was discontinued in 63 (24%) patients due to insufficient efficacy, in 29 (11%) for psychobehavioral adverse events, in 25 (10%) for other adverse events, and in 24 (9%) for other reasons.

SIGNIFICANCE

BRV showed a clinically useful 50% responder rate of 33% at 12 months and overall retention of >50%, despite 90% of included patients having previous LEV exposure. BRV was well tolerated; however, psychobehavioral adverse events occurred in one out of 10 patients. Although we identified short-term response and retention predictors, we could not identify significant predictors for long-term outcomes.

Eslicarbazepine acetate add-on therapy for drug-resistant focal epilepsy

BACKGROUND

This is an update of a review first published in 2011, and last updated in 2017. Most people with epilepsy have a good prognosis, but up to 30% of people continue to have seizures despite several regimens of antiepileptic drugs. In this review, we summarized the current evidence regarding eslicarbazepine acetate (ESL) when used as an add-on treatment for drug-resistant focal epilepsy.

OBJECTIVES

To evaluate the efficacy and tolerability of ESL when used as an add-on treatment for people with drug-resistant focal epilepsy.

SEARCH METHODS

For this update, we searched the following databases on 10 September 2020: Cochrane Register of Studies (CRS Web) and MEDLINE (Ovid). CRS Web includes randomized or quasi-randomized, controlled trials from Specialized Registers of Cochrane Review Groups including Epilepsy, CENTRAL, PubMed, Embase, ClinicalTrials.gov and the WHO ICTRP. There were no language restrictions. We reviewed the reference lists of retrieved studies and contacted the manufacturers of ESL and experts in the field for information about any unpublished or ongoing studies.

SELECTION CRITERIA

Randomized placebo-controlled double-blind add-on trials of ESL in people with drug-resistant focal epilepsy.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion and extracted data. Outcomes investigated included 50% or greater reduction in seizure frequency, seizure freedom, treatment withdrawal, adverse effects and drug interactions. Primary analyses were by intention to treat (ITT). The dose-response relationship was evaluated in regression models.

MAIN RESULTS

We included seven trials (2185 participants, aged 2 to 77 years), which were at low or unclear risk of bias apart from a high risk of attrition bias; all studies were funded by the pharmaceutical company, BIAL. The overall risk ratio (RR) for 50% or greater reduction in seizure frequency was 1.57 (95% confidence interval (CI) 1.34 to 1.83). For adults, the RR was 1.71 (95% CI 1.42 to 2.05; 5 studies, 1799 participants; moderate-certainty evidence); for children aged six to 18 years, the RR was 1.35 (95% CI 0.98 to 1.87; 2 studies, 322 participants; moderate-certainty evidence). Dose regression analysis showed evidence that ESL reduced seizure frequency with an increase in efficacy with increasing doses of ESL. ESL was associated with seizure freedom (RR 3.16, 95% CI 1.73 to 5.78; 6 studies, 1922 participants; moderate-certainty evidence). Participants were more likely to have ESL withdrawn for adverse effects (RR 2.72, 95% CI 1.66 to 4.46; 7 studies, 2185 participants; moderate-certainty evidence), but not for any reason (RR 1.25, 95% CI 0.93 to 1.70; 7 studies, 2185 participants; moderate-certainty evidence). The following adverse effects were associated with ESL: dizziness (RR 2.77, 99% CI 1.85 to 4.15); nausea (RR 2.55, 99% CI 1.39 to 4.67); somnolence (RR 1.75, 99% CI 1.18 to 2.61); diplopia (RR 4.07, 99% CI 1.86 to 8.89); and vomiting (RR 2.37, 99% CI 1.19 to 4.74). Overall, the certainty of the evidence was moderate due to a high discontinuation rate in studies of adults.

AUTHORS' CONCLUSIONS

ESL reduces seizure frequency when used as an add-on treatment for adults with drug-resistant focal epilepsy. The trials included in this review were of short-term duration. In addition, this update found that ESL may reduce seizure frequency in children from 6 to 18 years of age; however the results are inconclusive.

Adjunctive Perampanel in Older Patients With Epilepsy: A Multicenter Study of Clinical Practice

Background

Clinical data regarding use of newer antiseizure medications (ASMs) in an older population are limited. In randomized-controlled, placebo-controlled trials, older patients are under-represented, and protocols deviate markedly from routine clinical practice, limiting the external validity of results. Studies performed in a naturalistic setting are a useful complement to characterize the drug profile. Perampanel is a third-generation ASM and the first and only non-competitive alfa-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate receptor antagonist.

Objective

The aim of this study was to assess the effectiveness and tolerability of adjunctive perampanel over a 1‐year period in a population of older patients with epilepsy treated in a real-world setting.

Methods

Older (≥ 65 years of age) patients prescribed add-on perampanel at 12 Italian epilepsy centers were retrospectively identified. Seizure occurrence, adverse events (AEs), and drug withdrawal were analyzed. Effectiveness outcomes included the rates of seizure response (≥ 50% reduction in baseline monthly seizure frequency), seizure freedom, and treatment discontinuation. Safety and tolerability outcomes were the rate of treatment discontinuation due to AEs and the incidence of AEs.

Results

A total of 92 patients with a median age of 69 (range 65–88) years were included. The median daily dose of perampanel at 12 months was 6 mg (interquartile range 4–6 mg). At 12 months, 53 (57.6%) patients were seizure responders, and 22 (23.9%) patients were seizure free. Twenty (21.7%) patients discontinued perampanel; the reasons for treatment withdrawal were insufficient efficacy (n = 6/20; 30.0%), AEs (n = 12/20; 60.0%), and a combination of both (n = 2/20; 10%). The most common AEs included irritability (8.7%), somnolence (4.3%), and dizziness/vertigo (4.3%). The rate of behavioral and psychiatric AEs was higher in patients with history of psychiatric comorbidities (p = 0.044). There were no differences in the occurrence of behavioral and psychiatric AEs according to the concomitant use of levetiracetam (p = 0.776) and history of cognitive decline (p = 0.332).

Conclusions

Adjunctive perampanel was associated with improvement in seizure control and good tolerability in a real-life setting and can represent a viable therapeutic option in older patients with epilepsy.

Α Multicenter Retrospective Study Evaluating Brivaracetam in the Treatment of Epilepsies in Clinical Practice

Brivaracetam (BRV) is the latest approved antiepileptic drug. The aim of the study was to evaluate the efficacy and tolerability of BRV in everyday clinical practice. In this retrospective, observational, multicenter study, data from epilepsy patients receiving BRV from January 2018 to July 2019 were analyzed. Patients with age ≥16 suffering from any type of epilepsy and having at least one follow up encounter after dose titration were included. 156 consecutive patients were included in the study. The mean age was 40 (16-84 years) and the mean duration of epilepsy was 21 years. Of the 156 patients, 81% were diagnosed with focal-onset seizures, 16% with generalized seizures, while 3% suffered from unclassified seizures. Nine patients received BRV as monotherapy as a switching therapy. At the first follow up visit, seizure cessation was achieved in 56 (36%) patients and the rate of ≥50% responders was 36%. Twenty four patients (15%) remained unchanged; six patients (4%) were recorded with increased seizure frequency, while the remaining 9% had a response of less than 50%. Twenty-six patients (17%) showed clinically significant adverse events, but none were life threatening. Brivaracetam seems to be an effective, easy to use and safe antiepileptic drug in the clinical setting.

Adjunctive Brivaracetam in Focal Epilepsy: Real-World Evidence from the BRIVAracetam add-on First Italian netwoRk STudy (BRIVAFIRST)

BACKGROUND

In randomized controlled trials, add-on brivaracetam (BRV) reduced seizure frequency in patients with drug-resistant focal epilepsy. Studies performed in a naturalistic setting are a useful complement to characterize the drug profile.

OBJECTIVE

This multicentre study assessed the effectiveness and tolerability of adjunctive BRV in a large population of patients with focal epilepsy in the context of real-world clinical practice.

METHODS

The BRIVAFIRST (BRIVAracetam add-on First Italian netwoRk STudy) was a retrospective, multicentre study including adult patients prescribed adjunctive BRV. Patients with focal epilepsy and 12-month follow-up were considered. Main outcomes included the rates of seizure-freedom, seizure response (≥ 50% reduction in baseline seizure frequency), and treatment discontinuation. The incidence of adverse events (AEs) was also considered. Analyses by levetiracetam (LEV) status and concomitant use of strong enzyme-inducing antiseizure medications (EiASMs) and sodium channel blockers (SCBs) were performed.

RESULTS

A total of 1029 patients with a median age of 45 years (33-56) was included. At 12 months, 169 (16.4%) patients were seizure-free and 383 (37.2%) were seizure responders. The rate of seizure freedom was 22.3% in LEV-naive patients, 7.1% in patients with prior LEV use and discontinuation due to insufficient efficacy, and 31.2% in patients with prior LEV use and discontinuation due to AEs (p < 0.001); the corresponding values for ≥ 50% seizure frequency reduction were 47.9%, 29.7%, and 42.8% (p < 0.001). There were no statistically significant differences in seizure freedom and seizure response rates by use of strong EiASMs. The rates of seizure freedom (20.0% vs. 16.6%;  p = 0.341) and seizure response (39.7% vs. 26.9%; p = 0.006) were higher in patients receiving SCBs than those not receiving SCBs; 265 (25.8%) patients discontinued BRV. AEs were reported by 30.1% of patients, and were less common in patients treated with BRV and concomitant SCBs than those not treated with SCBs (28.9% vs. 39.8%; p = 0.017).

CONCLUSION

The BRIVAFIRST provided real-world evidence on the effectiveness of BRV in patients with focal epilepsy irrespective of LEV history and concomitant ASMs, and suggested favourable therapeutic combinations.

Utility of invasive electroencephalography in children 3 years old and younger with refractory epilepsy

OBJECTIVE

Early surgical intervention for pediatric refractory epilepsy is increasingly advocated as surgery has become safer and data have demonstrated improved outcomes with early seizure control. There is concern that the risks associated with staged invasive electroencephalography (EEG) in very young children outweigh the potential benefits. Here, the authors present a cohort of children with refractory epilepsy who were referred for invasive monitoring, and they evaluate the role and safety of staged invasive EEG in those 3 years old and younger.

METHODS

The authors conducted a retrospective review of children 3 years and younger with epilepsy, who had been managed surgically at two institutions between 2001 and 2015. A cohort of pediatric patients older than 3 years of age was used for comparison. Demographics, seizure etiology, surgical management, surgical complications, and adverse events were recorded. Statistical analysis was completed using Stata version 13. A p < 0.05 was considered statistically significant. Fisher's exact test was used to compare proportions.

RESULTS

Ninety-four patients (45 patients aged ≤ 3 [47.9%]) and 208 procedures were included for analysis. Eighty-six procedures (41.3%) were performed in children younger than 3 years versus 122 in the older cohort (58.7%). Forty-two patients underwent grid placement (14 patients aged ≤ 3 [33.3%]); 3 of them developed complications associated with the implant (3/42 [7.14%]), none of whom were among the younger cohort. Across all procedures, 11 complications occurred in the younger cohort versus 5 in the older patients (11/86 [12.8%] vs 5/122 [4.1%], p = 0.032). Two adverse events occurred in the younger group versus 1 in the older group (2/86 [2.32%] vs 1/122 [0.82%], p = 0.571). Following grid placement, 13/14 younger patients underwent guided resections compared to 20/28 older patients (92.9% vs 71.4%, p = 0.23).

CONCLUSIONS

While overall complication rates were higher in the younger cohort, subdural grid placement was not associated with an increased risk of surgical complications in that population. Invasive electrocorticography informs management in very young children with refractory, localization-related epilepsy and should therefore be used when clinically indicated.

Understanding the challenge of comparative effectiveness research in focal epilepsy: A review of network meta-analyses and real-world evidence on antiepileptic drugs

OBJECTIVE

Head-to-head randomized controlled trials (RCTs) are the gold standard for assessing comparative treatment effects. In the absence of direct comparisons between all possible antiepileptic drugs (AEDs), however, clinical decision-making in focal (partial onset) epilepsy relies on alternative evidence borne from indirect comparisons including network meta-analyses (NMAs) and from real-world evidence (RWE) studies. We review NMAs and observational RWE studies comparing AEDs in the adjunctive setting to compare the robustness of these methods and to formulate recommendations for future evidence development.

METHODS

A literature review identified NMAs and RWE studies comparing AEDs for the adjunctive treatment of focal seizures published between January 2008 and October 2018. NMAs were evaluated for robustness using a framework based on guidelines from the National Institute for Health and Care Excellence Decision Support Unit and the International Society for Pharmacoeconomics and Outcomes Research. RWE studies were evaluated using the GRACE checklist.

RESULTS

From a total of 1993 records, 11 NMAs and six RWE studies were eligible. Key limitations identified in the NMAs include nonsystematic selection of RCTs, unexplored heterogeneity between included RCTs in terms of study and patient characteristics, and selection of AEDs and AED doses or dosing strategies that are not reflective of clinical practice. The main limitations of RWE studies concern sample size, design, and analysis methods. Approximately 90% of comparisons between individual AEDs were nonsignificant in the NMAs. None of the RWE studies adjusted for baseline differences between comparator groups; therefore, they lack the validity to make comparative conclusions.

SIGNIFICANCE

Current NMAs and RWE studies provide only nominal comparative evidence for AED treatments in focal epilepsy, and should be used with caution for decision-making due to their methodological limitations. To overcome these hurdles, adherence to methodological guidelines and concerted efforts to collect relevant outcome data in the real world are needed.

Relative performance of brivaracetam as adjunctive treatment of focal seizures in adults: a network meta-analysis

Objective: To estimate the relative efficacy, safety and tolerability of adjunctive brivaracetam and other antiepileptic drugs (AEDs) using a Bayesian network meta-analysis (NMA) approach. Methods: A systematic literature review (SLR) identified randomized controlled trials of AEDs treating focal (partial-onset) seizures for ≥8 weeks and assessed them for inclusion in the NMA. Bayesian random-effects NMA was performed for several outcomes. All interventions within the licensed dose range were included in the network of evidence. Results: The SLR identified 82 studies; 65 were included in the NMA. These studies had baseline mean age 33.1-38.0 years, mean duration of epilepsy 18.7-23.0 years and median seizure frequency/28 days 8.1-11.8. All AEDs had significantly higher odds than placebo of achieving ≥50% responder rates (odds ratios 1.83-3.58) and all AEDs had a trend of higher odds than placebo of achieving seizure freedom (odds ratios 1.36-5.73), most being statistically significant. Tolerability outcomes were comparable between AEDs; most AEDs had higher odds than placebo of treatment-emergent adverse events leading to discontinuation, serious AEs, nausea, fatigue, dizziness and somnolence. Conclusions: This NMA would appear to show relative equivalence in efficacy, safety and tolerability outcomes of the included AEDs. However, patient heterogeneity within trials and in clinical practice should be considered when interpreting these results. While NMAs are based on the best available evidence the authors suggest that, due to the inability of NMAs to capture unmeasured confounding factors and population heterogeneity, NMAs must not be the sole basis for comparative treatment recommendations.

Subpial transection surgery for epilepsy

BACKGROUND

Nearly 30% of patients with epilepsy continue to have seizures despite using several antiepileptic drugs (AEDs). Such patients are regarded as having refractory, or uncontrolled, epilepsy. While there is no universally accepted definition of uncontrolled, or medically refractory, epilepsy, for the purposes of this review we will consider seizures as drug resistant if they have failed to respond to a minimum of two AEDs. Specialists consider that early surgical intervention may prevent seizures at a younger age, which in turn may improve the intellectual and social status of children. Many types of surgery are available for treating refractory epilepsy; one such procedure is known as subpial transection.

OBJECTIVES

To assess the effects of subpial transection for focal-onset seizures and generalised tonic-clonic seizures in children and adults.

SEARCH METHODS

For the latest update we searched the following databases on 7 August 2018: the Cochrane Register of Studies (CRS Web), which includes the Cochrane Epilepsy Group Specialized Register and the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid, 1946 to August 06, 2018), ClinicalTrials.gov, and the WHO International Clinical Trials Registry Platform (ICTRP). We imposed no language restrictions.

SELECTION CRITERIA

We considered all randomised and quasi-randomised parallel-group studies, whether blinded or non-blinded.

DATA COLLECTION AND ANALYSIS

Two review authors (BK and SR) independently screened trials identified by the search. The same two review authors planned to independently assess the methodological quality of studies. Had we identified studies for inclusion, one review author would have extracted the data, and the other would have verified the data.

MAIN RESULTS

We found no relevant studies.

AUTHORS' CONCLUSIONS

We found no evidence to support or refute the use of subpial transection surgery for patients with medically refractory epilepsy. Well-designed randomised controlled trials are needed to guide clinical practice.

From clinical trials of antiepileptic drugs to treatment

Rational prescribing should be based on the assessment of high-quality evidence about the benefits and risks of available treatment options. Because clinical trials, particularly randomized controlled trials (RCTs), provide the best source of evidence, their design and results need to be carefully scrutinized. The majority of RCTs of antiepileptic drugs (AEDs) have been designed to address regulatory requirements, and generally they involve restrictive eligibility criteria, rigid dosing schemes, short duration of follow-up, and comparison with placebo rather than standard treatments. Although these studies have high internal validity, they are conducted in a setting that is distant from routine clinical practice and therefore their usefulness in guiding treatment decisions is limited. Information more directly applicable to clinical practice can be derived from a relatively small number of comparative effectiveness monotherapy RCTs, although the design of some of these studies was probably biased in favor of the sponsor's product. Alarmingly, there is a paucity of well-designed trials in epilepsy syndromes other than focal epilepsies, and no RCTs at all in most of the less common epileptic syndromes of infancy and childhood. In the light of these shortcomings, there is scope for re-assessing regulatory requirements to facilitate generation of data more directly applicable to the routine clinical setting. Likewise, research-funding organizations should be sensitized about the lack of adequate evidence to guide therapeutic practice in epilepsy, and the need to promote high-quality comparative effectiveness trials. Future prospective pragmatic trials may benefit from the increasingly widespread availability of electronic health records.

Eslicarbazepine acetate add-on for drug-resistant partial epilepsy

BACKGROUND

This is an updated version of the Cochrane Review published in the Cochrane Library 2011, Issue 12.The majority of people with epilepsy have a good prognosis, but up to 30% of people continue to have seizures despite several regimens of antiepileptic drugs. In this review, we summarized the current evidence regarding eslicarbazepine acetate (ESL) when used as an add-on treatment for drug-resistant partial epilepsy.

OBJECTIVES

To evaluate the efficacy and tolerability of ESL when used as an add-on treatment for people with drug-resistant partial epilepsy.

SEARCH METHODS

The searches for the original review were run in November 2011. Subsequently, we searched the Cochrane Epilepsy Group Specialized Register (6 December 2016), the Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 11) and MEDLINE (1946 to 6 December 2016). There were no language restrictions. We reviewed the reference lists of retrieved studies to search for additional reports of relevant studies. We also contacted the manufacturers of ESL and experts in the field for information about any unpublished or ongoing studies.

SELECTION CRITERIA

Randomized placebo controlled double-blind add-on trials of ESL in people with drug-resistant partial epilepsy.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion and extracted data. Outcomes investigated included 50% or greater reduction in seizure frequency, seizure freedom, treatment withdrawal, adverse effects, and drug interactions. Primary analyses were by intention to treat (ITT). The dose-response relationship was evaluated in regression models.

MAIN RESULTS

We included five trials (1799 participants) rated at low risk of bias; all studies were funded by BIAL. The overall risk ratio (RR) with 95% confidence interval (CI) for 50% or greater reduction in seizure frequency was 1.71 (95% CI 1.42 to 2.05). Dose regression analysis showed evidence that ESL reduced seizure frequency with an increase in efficacy with increasing doses of ESL. ESL was significantly associated with seizure freedom (RR 2.90, 95% CI 1.49 to 5.68). Participants were more likely to have ESL withdrawn for adverse effects (RR 2.66, 95% CI 1.42 to 4.96) but not for any reason (RR 1.19, 95% CI 0.86 to 1.64). The following adverse effects were significantly associated with ESL: dizziness (RR 2.81, 99% CI 1.86 to 4.27); nausea (RR 2.61, 99% CI 1.36 to 5.01); diplopia (RR 4.14, 99% CI 1.74 to 9.84); somnolence (RR 1.71, 99% CI 1.11 to 2.63) and vomiting (RR 3.30, 99% CI 1.34 to 8.13). Overall the quality of the evidence was rated as moderate to high.

AUTHORS' CONCLUSIONS

ESL reduces seizure frequency when used as an add-on treatment for people with drug-resistant partial epilepsy. The trials included in this review were of short-term duration and focused on adults. One new trial has been included in this update, but the conclusions are unchanged.

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.

Can Matching-Adjusted Indirect Comparison Methods Mitigate Placebo Response Differences Among Patient Populations in Adjunctive Trials of Brivaracetam and Levetiracetam?

BACKGROUND AND OBJECTIVE

Patients with focal seizures recruited into adjunctive antiepileptic drug (AED) trials have become more refractory and severe over time; concurrently, placebo responses have increased. To attempt to account for heterogeneity among trials, propensity-score weighted patient-level data were used to indirectly compare placebo responses reported in brivaracetam and levetiracetam trials.

METHODS

Patient-level data from randomised, placebo-controlled brivaracetam (recruited 2007-2014) and levetiracetam (1993-1998) trials were pooled. Consistent inclusion/exclusion criteria were applied and outcomes were defined consistently. Potentially confounding baseline characteristics were adjusted for using propensity score weighting. Weighting success was assessed using placebo response.

RESULTS

In total, 707 and 473 active drug and 399 and 253 placebo patients comprised the brivaracetam and levetiracetam groups, respectively. Before weighting, several baseline variables were significantly different between groups; after weighting, prior vagal nerve stimulation, co-morbid depression and co-morbid anxiety remained different. Before weighting, median seizure frequency reduction was 21.7 and 3.9% in the brivaracetam and levetiracetam placebo arms, respectively; after weighting, median reduction was 15.0 and 6.0%. The comparison of non-randomised groups could be biased by unobserved confounding factors and region of residence. Lifetime AED history was unavailable in the brivaracetam trials and excluded from analysis.

CONCLUSIONS

Placebo responses remained different between brivaracetam and levetiracetam trials after propensity score weighting, indicating the presence of residual confounding factors associated with placebo response in these trials. It therefore remains problematic to conduct reliable indirect comparisons of brivaracetam and levetiracetam given the current evidence base, which may apply to comparisons between other AED trials.

WITHDRAWN: Oxcarbazepine add-on for drug-resistant partial epilepsy

BACKGROUND

Most people with epilepsy have a good prognosis and their seizures can be well controlled with the use of a single antiepileptic drug, but up to 30% develop refractory epilepsy, especially those with partial seizures. In this review we summarize the current evidence regarding oxcarbazepine when used as an add-on treatment for drug-resistant partial epilepsy.

OBJECTIVES

To evaluate the effects of oxcarbazepine when used as an add-on treatment for drug-resistant partial epilepsy.

SEARCH METHODS

We searched the Cochrane Epilepsy Group's Specialized Register (28 March 2006), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 1, 2006), MEDLINE (1966 to March 2006). No language restrictions were imposed. We checked the reference lists of retrieved studies for additional reports of relevant studies. We also contacted Novartis (manufacturers of oxcarbazepine) and experts in the field.

SELECTION CRITERIA

Randomized, placebo-controlled, double-blinded, add-on trials of oxcarbazepine in patients with drug-resistant partial epilepsy.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and extracted the relevant data. The following outcomes were assessed : (a) 50% or greater reduction in seizure frequency; (b) treatment withdrawal (any reason); (c) side effects. Primary analyses were intention-to-treat. Summary odds ratios were estimated for each outcome.

MAIN RESULTS

Two trials were included representing 961 randomized patients.Overall Odds Ratio (OR) (95% Confidence Interval (CIs)) for 50% or greater reduction in seizure frequency compared to placebo 2.96 (2.20, 4.00).Treatment withdrawal OR (95% CIs) compared to placebo 2.17 (1.59, 2.97).Side effects: OR (99% CIs) compared to placebo, ataxia 2.93 (1.72, 4.99); dizziness 3.05 (1.99, 4.67); fatigue 1.80 (1.02, 3.19); nausea 2.88 (1.77, 4.69); somnolence 2.55 (1.84, 3.55); diplopia 4.32 (2.65, 7.04), were significantly associated with oxcarbazepine.

AUTHORS' CONCLUSIONS

Oxcarbazepine has efficacy as an add-on treatment in patients with drug-resistant partial epilepsy, both in adults and children. However, trials reviewed were of relatively short duration, and provide no evidence about the long-term effects of oxcarbazepine. Results cannot be extrapolated to monotherapy or to patients with other epilepsy types.

Not all that glitters is gold: A guide to the critical interpretation of drug trials in epilepsy

Clinical trials represent the best source of evidence on which to base treatment decisions. For such evidence to be utilized meaningfully, however, it is essential that results are interpreted correctly. This requires a good understanding of strengths and weaknesses of the adopted design, the clinical relevance of the outcome measures, and the many factors that could affect such outcomes. As a general rule, uncontrolled studies tend to provide misleading evidence as a result of the impact of confounders such as regression to the mean, patient‐related bias, and observer bias. On the other hand, although randomized controlled trials (RCTs) are qualitatively superior, aspects of their execution may still decrease their validity. Bias and decreased validity in RCTs may occur by chance alone (for example, treatment groups may not necessarily be balanced for important variables despite randomization) or because of specific features of the trial design. In the case of industry‐driven studies, bias often influences the outcome in favor of the sponsor's product. Factors that need to be carefully scrutinized include (1) the purpose for which the trial is conducted; (2) potential bias due to unblinding or lack of blinding; (3) the appropriateness of the control group; (4) the power of the study in detecting clinically relevant differences; (5) the extent to which eligibility criteria could affect outcomes and be representative of routine clinical practice; (6) whether the treatments being compared are used optimally in terms of dosing, duration of treatment, and other variables; (7) the appropriateness of the statistical comparisons; (8) the clinical relevance of the outcome measures and whether all key outcome information is reported (for example, responder rates in completers); and (9) potential bias in the way results are presented and discussed. This article discusses each of these aspects and illustrates the discussion with examples taken from published antiepileptic drug trials.

Subpial transection surgery for epilepsy

BACKGROUND

Nearly 30% of patients with epilepsy continue to have seizures in spite of using several antiepileptic drug (AED) regimens. Such patients are regarded as having refractory, or uncontrolled, epilepsy. No definition of uncontrolled, or medically refractory, epilepsy has been universally accepted, but for the purposes of this review, we will consider seizures as drug resistant if they have failed to respond to a minimum of two AEDs. It is believed that early surgical intervention may prevent seizures at a younger age, which, in turn, may improve the intellectual and social status of children. Many types of surgery are available for treatment of refractory epilepsy; one such procedure is known as subpial transection.

OBJECTIVES

To determine the benefits and adverse effects of subpial transection for partial-onset seizures and generalised tonic-clonic seizures in children and adults.

SEARCH METHODS

We searched the Cochrane Epilepsy Group Specialised Register (29 June 2015), the Cochrane Central Register of Controlled Trials (CENTRAL; May 2015, Issue 5) and MEDLINE (1946 to 29 June 2015). We imposed no language restrictions.

SELECTION CRITERIA

We considered all randomised and quasi-randomised parallel-group studies, whether blinded or non-blinded.

DATA COLLECTION AND ANALYSIS

Two review authors (BK and SR) independently screened trials identified by the search. The same two review authors planned to independently assess the methodological quality of studies. When studies were identified for inclusion, one review author would have extracted the data, and the other would have verified the data.

MAIN RESULTS

We found no relevant studies.

AUTHORS' CONCLUSIONS

We found no evidence to support or refute use of subpial transection surgery for patients with medically refractory epilepsy. Well-designed randomised controlled trials are needed to guide clinical practice.

Clinical and economic burden of adverse drug reactions

Adverse drug reactions (ADRs) are unwanted drug effects that have considerable economic as well as clinical costs as they often lead to hospital admission, prolongation of hospital stay and emergency department visits. Randomized controlled trials (RCTs) are the main premarketing methods used to detect and quantify ADRs but these have several limitations, such as limited study sample size and limited heterogeneity due to the exclusion of the frailest patients. In addition, ADRs due to inappropriate medication use occur often in the real world of clinical practice but not in RCTs. Postmarketing drug safety monitoring through pharmacovigilance activities, including mining of spontaneous reporting and carrying out observational prospective cohort or retrospective database studies, allow longer follow-up periods of patients with a much wider range of characteristics, providing valuable means for ADR detection, quantification and where possible reduction, reducing healthcare costs in the process. Overall, pharmacovigilance is aimed at identifying drug safety signals as early as possible, thus minimizing potential clinical and economic consequences of ADRs. The goal of this review is to explore the epidemiology and the costs of ADRs in routine care.

KOMET: an unblinded, randomised, two parallel-group, stratified trial comparing the effectiveness of levetiracetam with controlled-release carbamazepine and extended-release sodium valproate as monotherapy in patients with newly diagnosed epilepsy

OBJECTIVE

To compare the effectiveness of levetiracetam (LEV) with extended-release sodium valproate (VPA-ER) and controlled-release carbamazepine (CBZ-CR) as monotherapy in patients with newly diagnosed epilepsy.

METHODS

This unblinded, randomised, 52-week superiority trial (NCT00175903) recruited patients (≥16 years of age) with ≥2 unprovoked seizures in the previous 2 years and ≥1 in the previous 6 months. The physician chose VPA or CBZ as preferred standard treatment; each patient was randomised to standard treatment or LEV. The primary outcome was time to treatment withdrawal (LEV vs standard antiepileptic drugs (AEDs)). Analyses also compared LEV with VPA-ER, and LEV with CBZ-CR.

FINDINGS

1688 patients (mean age 41 years; 44% female) were randomised to LEV (n=841) or standard AEDs (n=847). Time to treatment withdrawal was not significantly different between LEV and standard AEDs: HR (95% CI) 0.90 (0.74 to 1.08). Time to treatment withdrawal (HR (95% CI)) was 1.02 (0.74 to 1.41) for LEV/VPA-ER and 0.84 (0.66 to 1.07) for LEV/CBZ-CR. Time to first seizure (HR, 95% CI) was significantly longer for standard AEDs, 1.20 (1.03 to 1.39), being 1.19 (0.93 to 1.54) for LEV/VPA-ER and 1.20 (0.99 to 1.46) for LEV/CBZ-CR. Estimated 12-month seizure freedom rates from randomisation: 58.7% LEV versus 64.5% VPA-ER; 50.5% LEV versus 56.7% CBZ-CR. Similar proportions of patients within each stratum reported at least one adverse event: 66.1% LEV versus 62.0% VPA-ER; 73.4% LEV versus 72.5% CBZ-CR.

CONCLUSIONS

LEV monotherapy was not superior to standard AEDs for the global outcome, namely time to treatment withdrawal, in patients with newly diagnosed focal or generalised seizures.

Subpial transection surgery for epilepsy

BACKGROUND

Nearly 30% of patients with epilepsy continue to have seizures in spite of several antiepileptic drug (AED) regimens. In such cases they are regarded as having refractory, or uncontrolled epilepsy.There is no universally accepted definition for uncontrolled or medically refractory epilepsy, but for the purpose of this review, we will consider seizures to be drug resistant if they failed to respond to a minimum of two AEDs. It is believed that early surgical intervention may prevent seizures at a younger age and improve the intellectual and social status of children. There are many types of surgery for refractory epilepsy with subpial transection being one.

OBJECTIVES

Our main aim is to determine the benefits and adverse effects of subpial transection for partial-onset seizures and generalised tonic-clonic seizures in children and adults.

SEARCH METHODS

We searched the Cochrane Epilepsy Group Specialised Register (8 August 2013), The Cochrane Central Register of Controlled Trials (CENTRAL Issue 7 of 12, The Cochrane Library July 2013), and MEDLINE (1946 to 8 August 2013). We did not impose any language restrictions.

SELECTION CRITERIA

We considered all randomised and quasi-randomised parallel group studies either blinded or non-blinded.

DATA COLLECTION AND ANALYSIS

Two review authors (BK and SR) independently screened the trials identified by the search. The same two authors planned to independently assess the methodological quality of studies. If studies had been identified for inclusion, one author would have extracted the data and the other would have verified it.

MAIN RESULTS

No relevant studies were found.

AUTHORS' CONCLUSIONS

There is no evidence to support or refute the use of subpial transection surgery for medically refractory cases of epilepsy. Well designed randomised controlled trials are needed in future to guide clinical practice.

Eslicarbazepine acetate add-on for drug-resistant partial epilepsy

BACKGROUND

The majority of people with epilepsy will have a good prognosis, but up to 30% of patients will continue to have seizures despite several regimens of antiepileptic drugs. In this review we summarized the current evidence regarding eslicarbazepine acetate (ESL) when used as an add-on treatment for drug-resistant partial epilepsy.

OBJECTIVES

To evaluate the efficacy and tolerability of ESL when used as an add-on treatment for people with drug-resistant partial epilepsy.

SEARCH METHODS

We searched the Cochrane Epilepsy Group Specialized Register (3 November 2011), The Cochrane Central Register of Controlled Trials (CENTRAL issue 4 of 4, The Cochrane Library 2011), and MEDLINE (1948 to October week 4, 2011). There were no language restrictions. We reviewed the reference lists of retrieved studies to search for additional reports of relevant studies. We also contacted the manufacturers of ESL and experts in the field for information about any unpublished or ongoing studies.

SELECTION CRITERIA

Randomized placebo controlled double-blind add-on trials of ESL in people with drug-resistant partial epilepsy.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion and extracted data. Outcomes investigated included 50% or greater reduction in seizure frequency; seizure freedom; treatment withdrawal; adverse effects; and drug interactions. Primary analyses were by intention to treat. The dose response relationship was evaluated in regression models.

MAIN RESULTS

Four trials (1146 participants) were included; all studies were funded by BIAL. The overall relative risk (RR) with 95% confidence interval (CIs) for 50% or greater reduction in seizure frequency outcome was 1.86 (95% CI 1.46 to 2.36). Dose regression analysis showed evidence that ESL reduced seizure frequency with an increase in efficacy with increasing doses of ESL. ESL was significantly associated with seizure freedom (RR 3.04, 95% CI 1.44 to 6.42). Participants seemed more likely (albeit not significantly) to have ESL withdrawn for adverse effects (RR 2.26, 95% CI 0.98 to 5.21) but not for any reason (RR 1.07, 95% CI 0.73 to 1.57). The following adverse effects were significantly associated with ESL: dizziness (RR 3.09, 99% CI 1.76 to 5.43); nausea (RR 3.06, 99% CI 1.07 to 8.74); and diplopia (RR 3.73, 99% CI 1.19 to 11.64).

AUTHORS' CONCLUSIONS

Eslicarbazepine acetate reduces seizure frequency when used as an add-on treatment for people with drug-resistant partial epilepsy. The trials included in this review were of short-term duration and focused on adults.

Effectiveness of the first antiepileptic drug in the treatment of pediatric epilepsy

Most previous studies on the effectiveness of the first antiepileptic drug have dealt with adults. The present retrospective study of 520 patients was designed to investigate the interaction among efficacy, tolerability, and overall effectiveness of the first antiepileptic drug in children with newly diagnosed epilepsy. A total of 344 patients became seizure-free with the first prescribed antiepileptic drug. A lower proportion of patients with symptomatic epilepsy (60.3%) or cryptogenic epilepsy (61.5%) became seizure-free, compared with patients with idiopathic epilepsy (73.8%), and more patients with symptomatic or cryptogenic epilepsy changed their treatments owing to intolerable side effects. Most patients (95.6%) received sodium valproate (n = 234), topiramate (n = 143), or carbamazepine (n = 120). The majority of seizure-free patients required only a moderate daily dose. Patients who took carbamazepine (16.7%) or topiramate (11.9%) had a higher incidence of adverse events, necessitating a change of treatment, compared with patients treated with valproate (4.3%), and fewer of them became seizure-free. Overall, 66.2% of the patients became seizure-free with the first-ever antiepileptic drug, and most of them at a moderate dose. Moreover, tolerability was as important as efficacy in determining overall effectiveness.

Designing clinical trials to assess antiepileptic drugs as monotherapy : difficulties and solutions

Designing monotherapy trials in epilepsy is fraught with many hurdles, including diagnostic and classification difficulties, sparse information regarding the natural history of the disorder, and ethical objections to the use of placebo or a suboptimal comparator in a condition where the consequences of therapeutic failure can be serious. These issues are further complicated by regulatory differences between the US and the EU.In the US, the FDA considers that evidence of efficacy requires demonstration of superiority to a comparator. Because available antiepileptic drugs possess relatively high efficacy, in most settings it is unrealistic to expect that a new treatment will be superior to a standard treatment used at optimized dosages. To circumvent this problem, trial designs have been developed whereby patients in the control group are assigned to receive a suboptimal comparator and are required to exit from the trial if seizure deterioration occurs. This allows demonstration of a between-group difference in efficacy endpoints, such as time to exit or time to first seizure. Although these trials have come under increasing criticism because of ethical concerns, extensive information is now available on the outcome of patients with chronic epilepsy randomized to suboptimal treatment in similarly designed conversion to monotherapy trials. This has allowed the construction of a dataset of historical controls against which response to a fully active treatment can be compared. A number of studies using this novel approach are now in progress.In the EU, in addition to requiring data on conversion to monotherapy in refractory patients, the European Medicines Agency stipulates that a monotherapy indication in newly diagnosed epilepsy can only be granted if a candidate drug has shown at least a similar benefit/risk balance compared with an acknowledged standard at its optimal use during an assessment period of no less than 1 year. This has led to the implementation of noninferiority trials, one of which has been completed and which led to approval of the monotherapy indication for levetiracetam in the EU. Noninferiority trials provide valuable data in a setting that most closely resembles routine clinical practice, but their interpretation can be complicated by uncertainties on assay sensitivity.Major evidence gaps in the treatment of epilepsy still remain and it is hoped that these will be addressed in the near future. High quality monotherapy trials are particularly needed to assess the comparative efficacy of older and newer drugs in less common epilepsy syndromes, including most generalized epilepsies, and to investigate the different treatment options in populations homogeneous not only in terms of syndromic classification, but also in terms of underlying aetiology and associated phenotypes.

Long-term effects of levetiracetam and topiramate in clinical practice: A head-to-head comparison

OBJECTIVE

Two of the most commonly prescribed new antiepileptic drugs as add-on therapy for patients with chronic refractory epilepsies are topiramate and levetiracetam. In regulatory trials, both drugs were characterized as very promising new antiepileptic drugs. However, results from these highly controlled short-term clinical trials cannot simply be extrapolated to everyday clinical practice, also because head-to-head comparisons are lacking. Therefore, results from long-term open label observational studies that compare two or more new AEDs are crucial to determine the long-term performance of competing new antiepileptic drugs in clinical practice.

METHOD

We analyzed all patients referred to a tertiary epilepsy centre who had been treated with topiramate from the introduction of the drug in spring 1993 up to a final assessment point mid-2002 and all patients who had been treated with LEV in the same centre from the introduction of the drug in early 2001 up to a final assessment point end-2003 using a medical information system.

RESULTS

Three hundred and one patients were included for levetiracetam and 429 patients for TPM. Retention rate after 1 year was 65.6% for LEV-treated patients and 51.7% for TPM-treated patients (p=0.0015). Similarly, retention rates for LEV were higher at the 24-month mark: 45.8% of LEV-treated patients and 38.3% of TPM-treated patients were still continuing treatment (p=0.0046). Adverse events led to drug discontinuation in 21.9% of TPM-treated patients compared to 6.0% of LEV-treated patients (p<0.001). The number of patients discontinuing treatment because of lack of efficacy was similar for both groups. Seizure freedom rates varied between 11.6 and 20.0% for TPM and between 11.1 and 14.3% for LEV per 6-months interval. Several important AED specific adverse events leading to drug discontinuation were identified, including neurocognitive side effects from TPM and mood disorders from LEV.

CONCLUSION

The retention rate for LEV is significantly higher than for TPM. LEV had a more favourable side effect profile than TPM with comparable efficacy. Patients on TPM discontinued treatment mainly because of neurocognitive side effects. In the treatment with LEV, the effects on mood must not be underestimated.

Levetiracetam in clinical practice: long-term experience in patients with refractory epilepsy referred to a tertiary epilepsy center

OBJECTIVE

For the treatment of patients with chronic refractory epilepsies, development of new antiepileptic drugs is crucial. Three regulatory trials have demonstrated that add-on levetiracetam is efficacious in patients with localization-related epilepsy. However, results from these highly controlled short-term clinical trials cannot simply be extrapolated to everyday clinical practice. Therefore, more information is needed about the long-term profile of a new antiepileptic drug in clinical practice.

METHOD

We analyzed all patients who had been treated with levetiracetam in the Epilepsy Centre Kempenhaeghe from the introduction of the drug in early 2001 up to a final assessment point, at the end of 2003, using a medical information system.

RESULTS

In total, 301 patients were included. One hundred thirty-eight patients (45.8%) discontinued LEV treatment during the 24-month follow-up period. Reasons for discontinuation were lack of efficacy in 15.9% of patients, adverse events in 6.0% of patients, and a combination of lack of efficacy and adverse events in 16.3% of patients. By Kaplan-Meier survival analysis, the continuation rate was 65.6% after 1 year and 45.8% after 2 years. About 15% of patients in this highly refractory group had a 3-month remission, whereas 10% of patients became seizure-free for longer periods. The most frequently reported side effects at the time of discontinuation were mood disorders, tiredness, and sleepiness. Variables predicting (dis)continuation of levetiracetam treatment could not be identified.

CONCLUSION

Levetiracetam is a new antiepileptic drug that appears to be a useful add-on treatment in patients with refractory epilepsy. Its side effect profile is mild, with mood disorders being the most dominant adverse event.

Epileptogenesis and rational therapeutic strategies

The understanding of neurobiological mechanisms of epileptogenesis is essential for rational approaches for a possible disease modification as well as treatment of underlying causes of the epilepsies. More effort is necessary to translate results from basic investigations into new approaches for clinical research and to better understand a relationship with findings from clinical studies. The following report is a condensed synapsis in which molecular mechanisms of epileptogenesis, pharmacological modulation of epileptogenesis, evidence based therapy, refractoriness and prediction of outcome is provided in order to stimulate further collaborative international research.

Overtreatment in epilepsy: how it occurs and how it can be avoided

In pharmacotherapy, overtreatment may be defined as an excessive drug load (that is, excessive drug dosages or unnecessary polypharmacy) leading to a suboptimal risk-to-benefit ratio. The risk of overtreatment in the pharmacological management of epilepsy is substantial and may have serious consequences in terms of a greater incidence and severity of adverse effects. These effects can range from subtle CNS impairment to overt toxic effects, including teratogenicity. Overtreatment also causes increased treatment costs and may even lead to a paradoxical deterioration in seizure control. The prevention and correction of overtreatment requires a thorough understanding of the situations and mechanisms that lead to inappropriate prescribing of antiepileptic drugs. These include initiating treatment in conditions where it is not indicated (for example, long-term prophylaxis after head trauma or supratentorial surgery in seizure-free patients), use of excessively fast titration rates, prescription of excessively high initial target dosages, failure to consider conditions associated with reduced dosage requirements (for example, old age or comorbidities associated with impaired drug clearance), and failure to consider the dose-response characteristics of the selected drug. Many patients whose seizures do not respond to the initially prescribed medication can be optimally managed by switching to monotherapy with an alternative agent; premature use of combination therapy represents another common form of overtreatment. Overtreatment may also result from a failure to adjust the dosage to prevent or compensate for adverse pharmacokinetic or pharmacodynamic drug interactions, and from a failure to reduce drug load in patients who have not benefited from high dosages or polypharmacy. While the measurement of drug concentrations can aid in minimising adverse effects, there is also a danger of overtreatment resulting from inappropriate interpretation of drug concentration data. Continuation of drug therapy in seizure-free patients in whom the risk-benefit ratio is in favour of gradual withdrawal may also be regarded as overtreatment. Tailoring therapy to the needs of the individual patient is the key to the successful management of epilepsy. Even though the importance of complete seizure control cannot be overemphasised, no patient should be made to suffer more from the adverse effects of treatment than from the manifestations of the seizure disorder.

Pregabalin: a new antiepileptic drug for refractory epilepsy

Pregabalin is a recently licensed and marketed antiepileptic drug for use as adjunctive treatment of partial epilepsy. It acts at presynaptic calcium channels, modulating neurotransmitter release in the CNS, properties it shares with gabapentin. Its clinical development over the past decade has included its use in the treatment of neuropathic pain, and generalized anxiety disorder, in addition to epilepsy. Three multi-centre randomised, double-blind, placebo-controlled trials enrolling patients with refractory partial epilepsy have demonstrated an antiepileptic effect of pregabalin against placebo, as adjunctive therapy, with 31-51% of patients showing a 50% reduction in seizure frequency. Adverse effects were dose related, the commonest being somnolence, dizziness, and ataxia. Weight gain was seen in 14% of patients on the highest dose of 600 mg/day. Around 9000 people have been exposed to pregabalin in its development for all indications. No idiosyncratic reactions have been described to date. Pregabalin may be a useful addition in the treatment of refractory partial epilepsy. As with all new AEDs long-term follow up and post marketing surveillance is required.

New antiepileptic drugs in practice--how do they perform in the real world?

Most large-scale clinical trials of antiepileptic drugs (AEDs) are undertaken for regulatory purposes and generate basic data supporting the efficacy and safety of a new treatment. They do not, however, provide all the information required for physicians to know how well the drug will work in clinical practice. One valuable approach to generating more clinically meaningful information is to assess AED treatment retention rates, which reflect the combination of efficacy and tolerability in the real world, and have historically been low. Long-term retention rate data are available for levetiracetam (LEV), topiramate, gabapentin, and lamotrigine, and these data suggest that LEV is more likely to retain patients than other new AEDs. In a recent tertiary care study involving mainly refractory patients, 11% of participants became seizure-free on LEV and nearly two-thirds were retained on long-term treatment. High seizure freedom rates and good tolerability reported with LEV in clinical trials thus appear to translate into improved treatment retention rates in clinical practice.

Tiagabine as add-on therapy may be more effective with valproic acid--open label, multicentre study of patients with focal epilepsy

The aim of the current study was to review the efficacy of tiagabine (TGB) as add-on therapy in patients with drug-resistant focal epilepsy under normal daily clinical practice, and try to identify those who had improvement. This was an open multicentre study conducted in Poland. A group of 330 patients were analysed. Patients received TGB up to 30-50 mg/day with adjustment within the therapeutic range and titration period. For statistical evaluation chi-square test and logistic analysis were used. At the 16-week follow-up visit, 71.4% patients were reported as responders, i.e. had a 50% or greater decrease in seizure frequency compared with baseline (P<0.001). One-third of patients were seizure-free at 16-week evaluation (P<0.001). The beneficial effect of TGB on seizure reduction was most marked in patients with partial seizures (P<0.001). Patients who used valproic acid (mean dose 1307 mg/day) had 61-85% higher chances for disappearance of seizures or reduction of their number by 50% or more. Patients who used carbamazepine (mean dose 800 mg/day) at a dose 1000 mg or higher mg/day had twice lower chance for reduction of seizures by 50% or more (OR=0.45; 95 CI 0.25-0.82). There was no statistical impact of sex, age and aetiology on probability of therapeutic effect.

External validity of randomised controlled trials: "to whom do the results of this trial apply?"

In making treatment decisions, doctors and patients must take into account relevant randomised controlled trials (RCTs) and systematic reviews. Relevance depends on external validity (or generalisability)--ie, whether the results can be reasonably applied to a definable group of patients in a particular clinical setting in routine practice. There is concern among clinicians that external validity is often poor, particularly for some pharmaceutical industry trials, a perception that has led to underuse of treatments that are effective. Yet researchers, funding agencies, ethics committees, the pharmaceutical industry, medical journals, and governmental regulators alike all neglect external validity, leaving clinicians to make judgments. However, reporting of the determinants of external validity in trial publications and systematic reviews is usually inadequate. This review discusses those determinants, presents a checklist for clinicians, and makes recommendations for greater consideration of external validity in the design and reporting of RCTs.

Phenobarbital for the Treatment of Epilepsy in the 21st Century: A Critical Review

SUMMARY

Phenobarbital (PB) is the most widely used antiepileptic drug (AED) in the developing world and remains a popular choice in many industrialized countries. Meta-analyses of randomized controlled trials suggest that few differences in efficacy exist between PB and other established AEDs, but its possible deleterious cognitive and behavioral side effects remain a concern in the developed world. In contrast, high degrees of efficacy and tolerability in everyday clinical use have been demonstrated consistently in observational studies in developing countries. We propose that a pragmatic, comprehensive outcomes program be carried out, perhaps under the aegis of the Global Campaign Against Epilepsy, to optimize the conditions of the use of PB, so that more people around the world can benefit from this cost-effective medication and live more fulfilling lives.

Current trends in antiepileptic drug therapy

Over the last two decades, drug therapy for epilepsy has improved substantially. This can be ascribed to a large extent to three factors, including the demonstration of the advantages of monotherapy; the realization of the need for dosage tailoring, coupled [for some antiepileptic drugs (AEDs)] with control of pharmacokinetic variability through therapeutic drug monitoring; and the introduction of newer agents with improved tolerability profiles. What further advances should we expect for the future? Current trends that are expected to increasingly affect our prescribing patterns include greater reliance on evidence-based medicine and treatment guidelines, a trend that will be facilitated by completion of therapeutically meaningful randomized trials (including cost-effectiveness studies) and high-quality observational studies (including multinational pregnancy registries), as well as initiatives from scientific societies and government organizations aimed at condensing the most relevant information into therapeutic guidelines. The explosion in communication technology will accelerate dissemination of this information and its application to clinical practice. Other factors include a more rational patient-tailored AED selection and dose individualization, aided by characterization of predictors of outcome as defined by clinical parameters (sex, age, epilepsy syndrome, and etiology), pathophysiological mechanisms, and newly discovered genetic markers of outcome; improved definition of the role of new AEDs, resulting in their increased use in newly diagnosed epilepsy; and reappraisal of the value of combination therapy in refractory epilepsies, based on evidence produced by experimental and clinical studies designed to identify favorable pharmacodynamic interactions. Additional important developments may come from the discovery of novel, more efficacious AEDs and from exploration of potential new targets, such as prevention of epileptogenesis.