Carbamazepine versus phenobarbitone monotherapy for epilepsy: an individual participant data review

Carbamazepine Induces Platelet Apoptosis and Thrombocytopenia Through Protein Kinase A

Carbamazepine is extensively used worldwide to treat a wide range of disorders such as epilepsy, peripheral neuralgia and bipolar disorder. Thrombocytopenia and hemorrhage have been identified in multiple carbamazepine-treated patients. However, the underlying mechanism remains poorly understood. Here, we show that platelets undergo apoptosis after carbamazepine treatment. The apoptotic platelets induced by carbamazepine are rapidly removed in vivo, which accounts for thrombocytopenia. We found that carbamazepine treatment attenuates the phosphorylation level of bcl-xl/bcl-2-associated death promoter (BAD), vasodilator-associated stimulated phosphoprotein (VASP) and GPIbβ in platelets, indicating an inhibition effect on protein kinase A (PKA). We further demonstrated that carbamazepine reduced PKA activity through PI3K/Akt/PDE3A signaling pathway. Pharmacological activation of PKA or inhibition of PI3K/Akt/PDE3A protects platelets from apoptosis induced by carbamazepine. Importantly, PDE3A inhibitors or PKA activator ameliorates carbamazepine-mediated thrombocytopenia in vivo. These findings shed light on a possible mechanism of carbamazepine-induced thrombocytopenia, designating PDE3A/PKA as a potential therapeutic target in the treatment of carbamazepine-induced thrombocytopenia.

Carbamazepine versus phenobarbitone monotherapy for epilepsy: an individual participant data review

BACKGROUND

This is an updated version of the Cochrane Review previously published in 2016. This review is one in a series of Cochrane Reviews investigating pair-wise monotherapy comparisons.Epilepsy is a common neurological condition in which abnormal electrical discharges from the brain cause recurrent unprovoked seizures. It is believed that with effective drug treatment, up to 70% of individuals with active epilepsy have the potential to become seizure-free and go into long-term remission shortly after starting drug therapy with a single antiepileptic drug in monotherapy.Worldwide, carbamazepine and phenobarbitone are commonly used broad-spectrum antiepileptic drugs, suitable for most epileptic seizure types. Carbamazepine is a current first-line treatment for focal onset seizures, and is used in the USA and Europe. Phenobarbitone is no longer considered a first-line treatment because of concerns over associated adverse events, particularly documented behavioural adverse events in children treated with the drug. However, phenobarbitone is still commonly used in low- and middle-income countries because of its low cost. No consistent differences in efficacy have been found between carbamazepine and phenobarbitone in individual trials; however, the confidence intervals generated by these trials are wide, and therefore, synthesising the data of the individual trials may show differences in efficacy.

OBJECTIVES

To review the time to treatment failure, remission and first seizure with carbamazepine compared with phenobarbitone when used as monotherapy in people with focal onset seizures (simple or complex focal and secondarily generalised), or generalised onset tonic-clonic seizures (with or without other generalised seizure types).

SEARCH METHODS

For the latest update, we searched the following databases on 24 May 2018: the Cochrane Register of Studies (CRS Web), which includes Cochrane Epilepsy's Specialized Register and CENTRAL; MEDLINE; the US National Institutes of Health Ongoing Trials Register (ClinicalTrials.gov); and the World Health Organization International Clinical Trials Registry Platform (ICTRP). We handsearched relevant journals and contacted pharmaceutical companies, original trial investigators, and experts in the field.

SELECTION CRITERIA

Randomised controlled trials comparing monotherapy with either carbamazepine or phenobarbitone in children or adults with focal onset seizures or generalised onset tonic-clonic seizures.

DATA COLLECTION AND ANALYSIS

This was an individual participant data (IPD), review. Our primary outcome was time to treatment failure. Our secondary outcomes were time to first seizure post-randomisation, time to six-month remission, time to 12-month remission, and incidence of adverse events. We used Cox proportional hazards regression models to obtain trial-specific estimates of hazard ratios (HRs), with 95% confidence intervals (CIs), using the generic inverse variance method to obtain the overall pooled HR and 95% CI.

MAIN RESULTS

We included 13 trials in this review and IPD were available for 836 individuals out of 1455 eligible individuals from six trials, 57% of the potential data. For remission outcomes, a HR of less than 1 indicates an advantage for phenobarbitone and for first seizure and treatment failure outcomes a HR of less than 1 indicates an advantage for carbamazepine.Results for the primary outcome of the review were: time to treatment failure for any reason related to treatment (pooled HR adjusted for seizure type for 676 participants: 0.66, 95% CI 0.50 to 0.86, moderate-quality evidence), time to treatment failure due to adverse events (pooled HR adjusted for seizure type for 619 participants: 0.69, 95% CI 0.49 to 0.97, low-quality evidence), time to treatment failure due to lack of efficacy (pooled HR adjusted for seizure type for 487 participants: 0.54, 95% CI 0.38 to 0.78, moderate-quality evidence), showing a statistically significant advantage for carbamazepine compared to phenobarbitone.For our secondary outcomes, we did not find any statistically significant differences between carbamazepine and phenobarbitone: time to first seizure post-randomisation (pooled HR adjusted for seizure type for 822 participants: 1.13, 95% CI 0.93 to 1.38, moderate-quality evidence), time to 12-month remission (pooled HR adjusted for seizure type for 683 participants: 1.09, 95% CI 0.84 to 1.40, low-quality evidence), and time to six-month remission pooled HR adjusted for seizure type for 683 participants: 1.01, 95% CI 0.81 to 1.24, low-quality evidence).Results of these secondary outcomes suggest that there may be an association between treatment effect in terms of efficacy and seizure type; that is, that participants with focal onset seizures experience seizure recurrence later and hence remission of seizures earlier on phenobarbitone than carbamazepine, and vice versa for individuals with generalised seizures. It is likely that the analyses of these outcomes were confounded by several methodological issues and misclassification of seizure type, which could have introduced the heterogeneity and bias into the results of this review.Limited information was available regarding adverse events in the trials and we could not compare the rates of adverse events between carbamazepine and phenobarbitone. Some adverse events reported on both drugs were abdominal pain, nausea, and vomiting, drowsiness, motor and cognitive disturbances, dysmorphic side effects (such as rash), and behavioural side effects in three paediatric trials.

AUTHORS' CONCLUSIONS

Moderate-quality evidence from this review suggests that carbamazepine is likely to be a more effective drug than phenobarbitone in terms of treatment retention (treatment failures due to lack of efficacy or adverse events or both). Moderate- to low-quality evidence from this review also suggests an association between treatment efficacy and seizure type in terms of seizure recurrence and seizure remission, with an advantage for phenobarbitone for focal onset seizures and an advantage for carbamazepine for generalised onset seizures.However, some of the trials contributing to the analyses had methodological inadequacies and inconsistencies that may have impacted upon the results of this review. Therefore, we do not suggest that results of this review alone should form the basis of a treatment choice for a patient with newly onset seizures. We recommend that future trials should be designed to the highest quality possible with consideration of masking, choice of population, classification of seizure type, duration of follow-up, choice of outcomes and analysis, and presentation of results.

Lamotrigine versus carbamazepine monotherapy for epilepsy: an individual participant data review

BACKGROUND

This is an updated version of the original Cochrane Review published in Issue 11, 2006 of the Cochrane Database of Systematic Reviews.Epilepsy is a common neurological condition in which abnormal electrical discharges from the brain cause recurrent unprovoked seizures. It is believed that with effective drug treatment up to 70% of individuals with active epilepsy have the potential to become seizure-free, and to go into long-term remission shortly after starting drug therapy with a single antiepileptic drug (AED) in monotherapy.The correct choice of first-line AED for individuals with newly diagnosed seizures is of great importance. It is important that the choice of AEDs for an individual is made using the highest quality evidence regarding the potential benefits and harms of the various treatments.Carbamazepine or lamotrigine are recommended as first-line treatments for new onset focal seizures and as a first- or second-line treatment for generalised tonic-clonic seizures. Performing a synthesis of the evidence from existing trials will increase the precision of the results for outcomes relating to efficacy and tolerability and may assist in informing a choice between the two drugs.

OBJECTIVES

To review the time to treatment failure, remission and first seizure with lamotrigine compared to carbamazepine when used as monotherapy in people with focal onset seizures (simple or complex focal and secondarily generalised) or generalised onset tonic-clonic seizures (with or without other generalised seizure types).

SEARCH METHODS

We conducted the first searches for this review in 1997. For the most recent update, we searched the Cochrane Epilepsy Group Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL) via the Cochrane Register of Studies Online (CRSO), MEDLINE, Clinical Trials.gov and the WHO International Clinical Trials Registry Platform on 26 February 2018, without language restrictions SELECTION CRITERIA: Randomised controlled trials comparing monotherapy with either carbamazepine or lamotrigine in children or adults with focal onset seizures or generalised onset tonic-clonic seizures DATA COLLECTION AND ANALYSIS: This was an individual participant data (IPD) review. Our primary outcome was time to treatment failure and our secondary outcomes were time to first seizure post randomisation, time to six-month, 12-month and 24-month remission, and incidence of adverse events. We used Cox proportional hazards regression models to obtain trial-specific estimates of hazard ratios (HRs) with 95% confidence intervals (CIs), using the generic inverse variance method to obtain the overall pooled HR and 95% CI.

MAIN RESULTS

We included 14 trials in this review. Individual participant data were available for 2572 participants out of 3787 eligible individuals from nine out of 14 trials: 68% of the potential data. For remission outcomes, a HR of less than one indicated an advantage for carbamazepine; and for first seizure and treatment failure outcomes, a HR of less than one indicated an advantage for lamotrigine.The main overall results were: time to treatment failure for any reason related to treatment (pooled HR adjusted for seizure type: 0.71, 95% CI 0.62 to 0.82, moderate-quality evidence), time to treatment failure due to adverse events (pooled HR adjusted for seizure type: 0.55 (95% CI 0.45 to 0.66, moderate-quality evidence), time to treatment failure due to lack of efficacy (pooled HR for all participants: 1.03 (95% CI 0.75 to 1.41), moderate-quality evidence) showing a significant advantage for lamotrigine compared to carbamazepine in terms of treatment failure for any reason related to treatment and treatment failure due to adverse events, but no different between drugs for treatment failure due to lack of efficacy.Time to first seizure (pooled HR adjusted for seizure type: 1.26, 95% CI 1.12 to 1.41, high-quality evidence) and time to six-month remission (pooled HR adjusted for seizure type: 0.86, 95% CI 0.76 to 0.97, high-quality evidence), showed a significant advantage for carbamazepine compared to lamotrigine for first seizure and six-month remission. We found no difference between the drugs for time to 12-month remission (pooled HR for all participants 0.91, 95% CI 0.77 to 1.07, high-quality evidence) or time to 24-month remission (HR for all participants 1.00, 95% CI 0.80 to 1.25, high-quality evidence), however only two trials followed up participants for more than one year so evidence is limited.The results of this review are applicable mainly to individuals with focal onset seizures; 88% of included individuals experienced seizures of this type at baseline. Up to 50% of the limited number of individuals classified as experiencing generalised onset seizures at baseline may have had their seizure type misclassified, therefore we recommend caution when interpreting the results of this review for individuals with generalised onset seizures.The most commonly reported adverse events for both of the drugs across all of the included trials were dizziness, fatigue, gastrointestinal disturbances, headache and skin problems. The rate of adverse events was similar across the two drugs.The methodological quality of the included trials was generally good, however there is some evidence that the design choice of masked or open-label treatment may have influenced the treatment failure and withdrawal rates of the trials. Hence, we judged the quality of the evidence for the primary outcome of treatment failure to be moderate for individuals with focal onset seizures and low for individuals with generalised onset seizures. For efficacy outcomes (first seizure, remission), we judged the quality of evidence to be high for individuals with focal onset seizures and moderate for individuals with generalised onset seizures.

AUTHORS' CONCLUSIONS

Moderate quality evidence indicates that treatment failure for any reason related to treatment or due to adverse events occurs significantly earlier on carbamazepine than lamotrigine, but the results for time to first seizure suggested that carbamazepine may be superior in terms of seizure control. The choice between these first-line treatments must be made with careful consideration. We recommend that future trials should be designed to the highest quality possible with consideration of masking, choice of population, classification of seizure type, duration of follow-up, choice of outcomes and analysis, and presentation of results.

Antiepileptic drug monotherapy for epilepsy: a network meta-analysis of individual participant data

BACKGROUND

Epilepsy is a common neurological condition with a worldwide prevalence of around 1%. Approximately 60% to 70% of people with epilepsy will achieve a longer-term remission from seizures, and most achieve that remission shortly after starting antiepileptic drug treatment. Most people with epilepsy are treated with a single antiepileptic drug (monotherapy) and current guidelines from the National Institute for Health and Care Excellence (NICE) in the United Kingdom for adults and children recommend carbamazepine or lamotrigine as first-line treatment for partial onset seizures and sodium valproate for generalised onset seizures; however a range of other antiepileptic drug (AED) treatments are available, and evidence is needed regarding their comparative effectiveness in order to inform treatment choices.

OBJECTIVES

To compare the time to withdrawal of allocated treatment, remission and first seizure of 10 AEDs (carbamazepine, phenytoin, sodium valproate, phenobarbitone, oxcarbazepine, lamotrigine, gabapentin, topiramate, levetiracetam, zonisamide) currently used as monotherapy in children and adults with partial onset seizures (simple partial, complex partial or secondary generalised) or generalised tonic-clonic seizures with or without other generalised seizure types (absence, myoclonus).

SEARCH METHODS

We searched the following databases: Cochrane Epilepsy's Specialised Register, CENTRAL, MEDLINE and SCOPUS, and two clinical trials registers. We handsearched relevant journals and contacted pharmaceutical companies, original trial investigators, and experts in the field. The date of the most recent search was 27 July 2016.

SELECTION CRITERIA

We included randomised controlled trials of a monotherapy design in adults or children with partial onset seizures or generalised onset tonic-clonic seizures (with or without other generalised seizure types).

DATA COLLECTION AND ANALYSIS

This was an individual participant data (IPD) review and network meta-analysis. Our primary outcome was 'time to withdrawal of allocated treatment', and our secondary outcomes were 'time to achieve 12-month remission', 'time to achieve six-month remission', 'time to first seizure post-randomisation', and 'occurrence of adverse events'. We presented all time-to-event outcomes as Cox proportional hazard ratios (HRs) with 95% confidence intervals (CIs). We performed pairwise meta-analysis of head-to-head comparisons between drugs within trials to obtain 'direct' treatment effect estimates and we performed frequentist network meta-analysis to combine direct evidence with indirect evidence across the treatment network of 10 drugs. We investigated inconsistency between direct estimates and network meta-analysis via node splitting. Due to variability in methods and detail of reporting adverse events, we have not performed an analysis. We have provided a narrative summary of the most commonly reported adverse events.

MAIN RESULTS

IPD was provided for at least one outcome of this review for 12,391 out of a total of 17,961 eligible participants (69% of total data) from 36 out of the 77 eligible trials (47% of total trials). We could not include IPD from the remaining 41 trials in analysis for a variety of reasons, such as being unable to contact an author or sponsor to request data, data being lost or no longer available, cost and resources required to prepare data being prohibitive, or local authority or country-specific restrictions.We were able to calculate direct treatment effect estimates for between half and two thirds of comparisons across the outcomes of the review, however for many of the comparisons, data were contributed by only a single trial or by a small number of participants, so confidence intervals of estimates were wide.Network meta-analysis showed that for the primary outcome 'Time to withdrawal of allocated treatment,' for individuals with partial seizures; levetiracetam performed (statistically) significantly better than current first-line treatment carbamazepine and other current first-line treatment lamotrigine performed better than all other treatments (aside from levetiracetam); carbamazepine performed significantly better than gabapentin and phenobarbitone (high-quality evidence). For individuals with generalised onset seizures, first-line treatment sodium valproate performed significantly better than carbamazepine, topiramate and phenobarbitone (moderate- to high-quality evidence). Furthermore, for both partial and generalised onset seizures, the earliest licenced treatment, phenobarbitone seems to perform worse than all other treatments (moderate- to high-quality evidence).Network meta-analysis also showed that for secondary outcomes 'Time to 12-month remission of seizures' and 'Time to six-month remission of seizures,' few notable differences were shown for either partial or generalised seizure types (moderate- to high-quality evidence). For secondary outcome 'Time to first seizure,' for individuals with partial seizures; phenobarbitone performed significantly better than both current first-line treatments carbamazepine and lamotrigine; carbamazepine performed significantly better than sodium valproate, gabapentin and lamotrigine. Phenytoin also performed significantly better than lamotrigine (high-quality evidence). In general, the earliest licenced treatments (phenytoin and phenobarbitone) performed better than the other treatments for both seizure types (moderate- to high-quality evidence).Generally, direct evidence and network meta-analysis estimates (direct plus indirect evidence) were numerically similar and consistent with confidence intervals of effect sizes overlapping.The most commonly reported adverse events across all drugs were drowsiness/fatigue, headache or migraine, gastrointestinal disturbances, dizziness/faintness and rash or skin disorders.

AUTHORS' CONCLUSIONS

Overall, the high-quality evidence provided by this review supports current guidance (e.g. NICE) that carbamazepine and lamotrigine are suitable first-line treatments for individuals with partial onset seizures and also demonstrates that levetiracetam may be a suitable alternative. High-quality evidence from this review also supports the use of sodium valproate as the first-line treatment for individuals with generalised tonic-clonic seizures (with or without other generalised seizure types) and also demonstrates that lamotrigine and levetiracetam would be suitable alternatives to either of these first-line treatments, particularly for those of childbearing potential, for whom sodium valproate may not be an appropriate treatment option due to teratogenicity.

Antiepileptic drug monotherapy for epilepsy: a network meta-analysis of individual participant data

BACKGROUND

Epilepsy is a common neurological condition with a worldwide prevalence of around 1%. Approximately 60% to 70% of people with epilepsy will achieve a longer-term remission from seizures, and most achieve that remission shortly after starting antiepileptic drug treatment. Most people with epilepsy are treated with a single antiepileptic drug (monotherapy) and current guidelines from the National Institute for Health and Care Excellence (NICE) in the United Kingdom for adults and children recommend carbamazepine or lamotrigine as first-line treatment for partial onset seizures and sodium valproate for generalised onset seizures; however a range of other antiepileptic drug (AED) treatments are available, and evidence is needed regarding their comparative effectiveness in order to inform treatment choices.

OBJECTIVES

To compare the time to withdrawal of allocated treatment, remission and first seizure of 10 AEDs (carbamazepine, phenytoin, sodium valproate, phenobarbitone, oxcarbazepine, lamotrigine, gabapentin, topiramate, levetiracetam, zonisamide) currently used as monotherapy in children and adults with partial onset seizures (simple partial, complex partial or secondary generalised) or generalised tonic-clonic seizures with or without other generalised seizure types (absence, myoclonus).

SEARCH METHODS

We searched the following databases: Cochrane Epilepsy's Specialised Register, CENTRAL, MEDLINE and SCOPUS, and two clinical trials registers. We handsearched relevant journals and contacted pharmaceutical companies, original trial investigators, and experts in the field. The date of the most recent search was 27 July 2016.

SELECTION CRITERIA

We included randomised controlled trials of a monotherapy design in adults or children with partial onset seizures or generalised onset tonic-clonic seizures (with or without other generalised seizure types).

DATA COLLECTION AND ANALYSIS

This was an individual participant data (IPD) review and network meta-analysis. Our primary outcome was 'time to withdrawal of allocated treatment', and our secondary outcomes were 'time to achieve 12-month remission', 'time to achieve six-month remission', 'time to first seizure post-randomisation', and 'occurrence of adverse events'. We presented all time-to-event outcomes as Cox proportional hazard ratios (HRs) with 95% confidence intervals (CIs). We performed pairwise meta-analysis of head-to-head comparisons between drugs within trials to obtain 'direct' treatment effect estimates and we performed frequentist network meta-analysis to combine direct evidence with indirect evidence across the treatment network of 10 drugs. We investigated inconsistency between direct estimates and network meta-analysis via node splitting. Due to variability in methods and detail of reporting adverse events, we have not performed an analysis. We have provided a narrative summary of the most commonly reported adverse events.

MAIN RESULTS

IPD was provided for at least one outcome of this review for 12,391 out of a total of 17,961 eligible participants (69% of total data) from 36 out of the 77 eligible trials (47% of total trials). We could not include IPD from the remaining 41 trials in analysis for a variety of reasons, such as being unable to contact an author or sponsor to request data, data being lost or no longer available, cost and resources required to prepare data being prohibitive, or local authority or country-specific restrictions.We were able to calculate direct treatment effect estimates for between half and two thirds of comparisons across the outcomes of the review, however for many of the comparisons, data were contributed by only a single trial or by a small number of participants, so confidence intervals of estimates were wide.Network meta-analysis showed that for the primary outcome 'Time to withdrawal of allocated treatment,' for individuals with partial seizures; levetiracetam performed (statistically) significantly better than both current first-line treatments carbamazepine and lamotrigine; lamotrigine performed better than all other treatments (aside from levetiracetam), and carbamazepine performed significantly better than gabapentin and phenobarbitone (high-quality evidence). For individuals with generalised onset seizures, first-line treatment sodium valproate performed significantly better than carbamazepine, topiramate and phenobarbitone (moderate- to high-quality evidence). Furthermore, for both partial and generalised onset seizures, the earliest licenced treatment, phenobarbitone seems to perform worse than all other treatments (moderate- to high-quality evidence).Network meta-analysis also showed that for secondary outcomes 'Time to 12-month remission of seizures' and 'Time to six-month remission of seizures,' few notable differences were shown for either partial or generalised seizure types (moderate- to high-quality evidence). For secondary outcome 'Time to first seizure,' for individuals with partial seizures; phenobarbitone performed significantly better than both current first-line treatments carbamazepine and lamotrigine; carbamazepine performed significantly better than sodium valproate, gabapentin and lamotrigine. Phenytoin also performed significantly better than lamotrigine (high-quality evidence). In general, the earliest licenced treatments (phenytoin and phenobarbitone) performed better than the other treatments for both seizure types (moderate- to high-quality evidence).Generally, direct evidence and network meta-analysis estimates (direct plus indirect evidence) were numerically similar and consistent with confidence intervals of effect sizes overlapping.The most commonly reported adverse events across all drugs were drowsiness/fatigue, headache or migraine, gastrointestinal disturbances, dizziness/faintness and rash or skin disorders.

AUTHORS' CONCLUSIONS

Overall, the high-quality evidence provided by this review supports current guidance (e.g. NICE) that carbamazepine and lamotrigine are suitable first-line treatments for individuals with partial onset seizures and also demonstrates that levetiracetam may be a suitable alternative. High-quality evidence from this review also supports the use of sodium valproate as the first-line treatment for individuals with generalised tonic-clonic seizures (with or without other generalised seizure types) and also demonstrates that lamotrigine and levetiracetam would be suitable alternatives to either of these first-line treatments, particularly for those of childbearing potential, for whom sodium valproate may not be an appropriate treatment option due to teratogenicity.