Seizure-free Days Observed in Randomized Placebo-controlled Add-on Trials with Levetiracetam in Partial Epilepsy

Patient and Caregiver Health State Utilities in Lennox-Gastaut Syndrome and Dravet Syndrome

PURPOSE

Lennox-Gastaut syndrome (LGS) and Dravet syndrome (DS) are rare, treatment-resistant forms of epilepsy characterized by childhood onset of seizures. Cost-effectiveness analysis for new antiseizure medications typically requires health state utilities (HSUs) that reflect the patient and caregiver burden of the relevant conditions. This study aimed to estimate HSUs for LGS and DS. Focus was placed on valuing the impact of seizure frequency and seizure-free days on health-related quality of life (HRQL) for patients and caregivers.

METHODS

Health state vignettes that described the experience of living with and caring for a child with LGS or DS were developed based on a targeted literature review and feedback from interviews with LGS and DS clinical experts and DS caregivers. Vignettes varied by the number of seizures and seizure-free days per month. Twenty-four vignettes were developed that described patient HRQL (6 per condition) and caregiver HRQL (6 per condition) for LGS or DS. Vignettes were evaluated via interviews from the general population in the United Kingdom and Sweden using a visual analog scale and time trade-off (TTO) method. Participants were recruited by interviewers based in different regions of the United Kingdom and Sweden using convenience sampling.

FINDINGS

Two hundred interviews were conducted by video call from March to April 2020. One hundred participants evaluated each of the 6 patient and 6 caregiver vignettes for LGS; a different 100 participants evaluated each of the DS vignettes. The estimated utility values vary consistently according to seizure frequency and number of seizure-free days. Patient TTO utility values range from -0.186 (highest seizure frequency and fewest seizure-free days) to 0.754 (seizure-free state) for LGS and from 0.171 to 0.778 for DS. The caregiver TTO utility values range from 0.032 to 0.810 and 0.510 to 0.881 for LGS and DS, respectively. Fewer seizures and additional seizure-free days are associated with better patient and caregiver HRQL.

IMPLICATIONS

This study estimated utility values for patients with LGS or DS and their caregivers using visual analog scale and TTO valuation among a general public sample. These utility values can be used in cost-effectiveness assessments of new antiseizure medications. The findings indicate the importance of seizure-free days as well as seizure frequency in patient and caregiver HRQL, which may inform the design of future clinical trials.

Adjunctive perampanel and myoclonic and absence seizures: Post hoc analysis of data from study 332 in patients with idiopathic generalized epilepsy

PURPOSE

This post hoc analysis assessed the effects of adjunctive perampanel on myoclonic and absence seizure outcomes in patients (aged ≥12 years) with idiopathic generalized epilepsy (IGE) and generalized tonic-clonic seizures during the double-blind (up to 8 mg/day) and open-label extension (OLEx; up to 12 mg/day) phases of Study 332.

METHODS

Patients experiencing myoclonic and/or absence seizures during study baseline were included. Assessments for myoclonic and absence seizures included: median percent change in seizure frequency, number of seizure days and seizure-free days (all per 28 days), 50 % and 75 % responder rates, seizure-freedom rates, seizure worsening, and monitoring of treatment-emergent adverse events (TEAEs).

RESULTS

During the double-blind phase, myoclonic and/or absence seizures were reported in 47/163 and 60/163 patients, respectively. Median percent reductions in seizure frequency per 28 days from study baseline were 52.5% and 24.5% (myoclonic seizures) and 7.6 % and 41.2 % (absence seizures) for placebo and perampanel, respectively; seizure-freedom rates were 13.0 % and 16.7 % (myoclonic seizures) and 12.1 % and 22.2 % (absence seizures), respectively. During the OLEx phase, 46/138 and 52/138 patients experienced myoclonic and/or absence seizures, respectively. Responses during the double-blind phase were maintained during long-term (>104 weeks) adjunctive perampanel treatment. The frequency/type of TEAEs was consistent with the known safety profile of perampanel.

CONCLUSION

In this post hoc analysis, adjunctive perampanel was not associated with any overall worsening of absence seizures. Further research is needed to investigate the effect of adjunctive perampanel in IGE patients with myoclonic and/or absence seizures.

Pharmacokinetic Properties of New Antiepileptic Drugs

Eight new antiepileptic drugs (AEDs) have been approved for use within the United States within the past decade. They are felbamate, gabapentin, lamotrigine, levetiracetam, oxcarbazepine, tiagabine, topiramate, and zonisamide. These afford clinicians with more options to increase efficacy and tolerability in the treatment of patients with epilepsy. Pharmacokinetic properties and drug interactions with other AEDs and other medications taken for comorbidities are individually discussed for each of these new agents. Drug concentrations are not routinely monitored for these newer agents, and there have been few studies designed to investigate their concentration-effect relationships. For most of these medications, the concentrations observed in responders and nonresponders overlap considerably and levels associated with efficacy are often associated with adverse events, complicating the definition of target ranges. Also, epilepsy manifests itself sporadically causing difficulty in clinically monitoring efficacy of medications. Therapeutic drug monitoring provides for the individualization of treatment for these agents, which is important because they demonstrate significant variability in inter- and intraindividual pharmaco-kinetic properties. Therapeutic drug monitoring also allows for identification of noncompliance, drug interactions, and toxicity. Current knowledge of the relationships between efficacy, toxicity, and drug concentrations is discussed.

Meta-Analysis of Randomized Trials on First Line and Adjunctive Levetiracetam

Context:

New evidence suggests that levetiracetam may be as effective as traditional agents, with better safety profile.

Objective:

To synthesize evidence regarding efficacy and tolerability of levetiracetam as first line, adjunctive or prophylactic antiepileptic agent.

Study Selection & Data Extraction:

Eligible studies were randomized controlled trials (RCTs) of levetiracetam used in adults with epilepsy. MEDLINE, EMBASE, CENTRAL, CINHAL, PAPERSFIRST, PROCEEDINGSFIRST, PROQUEST and conference proceedings identified studies (to September 30, 2010). Two investigators independently selected, appraised studies, collected and analyzed data.

Results:

Of ten eligible randomized trials, eight investigated adjunctive levetiracetam for refractory seizures, one as monotherapy for newly diagnosed seizures, one as monotherapy for prophylaxis. Eight RCTs of adjunctive levetiracetam were of moderate quality (GRADE criteria), with two showing lack of allocation concealment. Meta-analyses showed adjunctive levetiracetam was more effective than placebo in achieving at least 50% reduction of seizure frequency, when added to baseline antiepileptic regimen (pooled RR 2.15 [1.65,2.82], I2 = 45%, p value (heterogeneity) = 0.08, p value (overall effect) < 0.01). Likelihood of serious adverse events necessitating withdrawal from study was not significantly different between levetiracetam and control (pooled RR 1.37 [0.88,2.13], I2 = 0%, p value (heterogeneity) = 0.84, p value (overall effect) = 0.17). Subgroup analyses suggested similar effects across different dosages. Sensitivity analysis of studies with adequate concealment showed similar effects.

Conclusions:

Levetiracetam is an effective adjunctive agent for refractory epilepsy. More studies are needed to establish whether it is effective as monotherapy for newly diagnosed seizures, and for prophylaxis in traumatic brain injury.

Cost effectiveness of lacosamide in the adjunctive treatment of patients with refractory focal epilepsy in Belgium

OBJECTIVES

Lacosamide is an anti-epileptic drug, indicated as adjunctive therapy for patients with focal seizures with or without secondary generalization. This study aims to assess the cost effectiveness of standard anti-epileptic drug therapy plus lacosamide 300 mg/day compared with standard therapy alone from the perspective of the Belgian healthcare payer.

METHODS

The treatment pathway of a hypothetical cohort of 1000 patients over 2 years was simulated using a decision tree. Data about health state probabilities, seizure frequency and utility values were taken from lacosamide trials or from the literature. Effectiveness measures included the number of seizures avoided and the number of quality-adjusted life-years gained. Unit costs were taken from national references. Resource use was estimated by a panel of eight neurologists with extensive experience in epilepsy. The price year was 2008. Deterministic and probabilistic sensitivity analyses were conducted.

RESULTS

Over a 24-month period, standard anti-epileptic drug therapy plus lacosamide led to a reduction of seven seizures, an increase of 0.038 quality-adjusted life-years and a cost decrease of &U20AC;3619 per patient compared with standard therapy alone. Using a willingness to pay of &U20AC;30 000 per quality-adjusted life-year, the net monetary benefit of standard anti-epileptic drug therapy plus lacosamide amounted to &U20AC;4754. The probability of standard anti-epileptic drug therapy plus lacosamide being cost effective was 97.3%, 99.8%, 99.9% and 100% at 6, 12 , 18 and 24 months, respectively.

CONCLUSION

In patients with difficult-to-treat epilepsy, standard anti-epileptic drug therapy plus lacosamide appears to be a cost-effective option in Belgium.

Review of therapeutic options for adjuvant treatment of focal seizures in epilepsy: focus on lacosamide

Epilepsy is one of the most common serious neurological conditions worldwide, with an age-adjusted incidence of approximately 50 per 100,000 persons per year in developed countries. Antiepileptic therapy can result in long-term remission in 60-70% of patients, but many patients will require combination treatment to achieve optimal seizure control, as monotherapy is ineffective at controlling seizures in 30-53% of patients. Despite the increase in available treatment options, patient outcomes have not improved significantly and there is still a need for more effective therapies. Drugs used in the treatment of focal-onset seizures are a diverse range of compounds, and in most cases their mechanism of action is unknown or poorly defined. This review discusses the efficacy and safety of the newer adjuvant antiepileptic therapies that may improve outcomes in patients unresponsive to monotherapy, including clobazam, vigabatrin, lamotrigine, gabapentin, topiramate, tiagabine, levetiracetam, oxcarbazepine, pregabalin, zonisamide and eslicarbazepine, with focus on lacosamide. Lacosamide has been shown to exert its anticonvulsant effects predominantly by enhancement of the slow inactivation of voltage-gated sodium channels. Lacosamide is indicated for use as adjuvant treatment of focal-onset seizures in patients with epilepsy, and there is some evidence that it may also be of use in patients with status epilepticus and cancer patients with epilepsy. The efficacy of lacosamide has been assessed in three randomized, double-blind, placebo-controlled clinical trials, all of which have shown lacosamide to be effective at reducing seizure frequency and increasing 50% responder rates in patients with focal-onset seizures. Long-term lacosamide treatment is generally well tolerated and is not associated with significant drug interactions; the availability of an intravenous form of the drug also makes it particularly useful for a broad range of patients.

Modulation of abnormal synaptic transmission in hippocampal CA3 neurons of spontaneously epileptic rats (SERs) by levetiracetam

Levetiracetam (LEV) inhibits partial refractory epilepsy in human, and both convulsive and absence-like seizures in the spontaneously epileptic rat (SER). Two-thirds of hippocampal CA3 neurons in SER show a long-lasting depolarization shift, with accompanying repetitive firing upon mossy fiber stimulation. This abnormal excitability is probably attributable to abnormalities in the L-type Ca(2+) channels. We performed electrophysiological studies to elucidate the mechanism underlying the antiepileptic effects of LEV via intracellular recording from the hippocampal CA3 neurons in slice preparations of SER and non-epileptic Wistar rats. LEV (100 μM) inhibited the depolarization shift with repetitive firing by mossy fiber stimulation (MFS), without affecting the first spike in SER CA3 neurons. At a higher dose (1mM), LEV suppressed the first spike in all SER neurons (including the CA3 neurons which showed only a single action potential by MFS), while the single action potential of Wistar rat CA3 neurons remained unaffected. SER CA3 neurons with MFS-induced abnormal firing exhibited a higher number of repetitive spikes when a depolarization pulse was applied in the SER CA3 neurons. LEV (100 μM, 1mM) reduced the repetitive firing induced by a depolarization pulse applied without affecting Ca(2+) spike in SER neurons. LEV is known not to bind glutamate and gamma-aminobutyric acid (GABA) receptors. These findings suggest that the therapeutic concentration of LEV inhibits abnormal firing of the CA3 neurons by modulating abnormal synaptic transmission and abnormal Na(+) channels in SER.

Levetiracetam: a review of its use in epilepsy

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

Budget impact analysis of adjunctive therapy with lacosamide for partial-onset epileptic seizures in Belgium

OBJECTIVE

This study aims to compute the budget impact of lacosamide, a new adjunctive therapy for partial-onset seizures in epilepsy patients from 16 years of age who are uncontrolled and having previously used at least three anti-epileptic drugs from a Belgian healthcare payer perspective.

METHODS

The budget impact analysis compared the 'world with lacosamide' to the 'world without lacosamide' and calculated how a change in the mix of anti-epileptic drugs used to treat uncontrolled epilepsy would impact drug spending from 2008 to 2013. Data on the number of patients and on the market shares of anti-epileptic drugs were taken from Belgian sources and from the literature. Unit costs of anti-epileptic drugs originated from Belgian sources. The budget impact was calculated from two scenarios about the market uptake of lacosamide.

RESULTS

The Belgian target population is expected to increase from 5333 patients in 2008 to 5522 patients in 2013. Assuming that the market share of lacosamide increases linearly over time and is taken evenly from all other anti-epileptic drugs (AEDs), the budget impact of adopting adjunctive therapy with lacosamide increases from €5249 (0.1% of reference drug budget) in 2008 to €242,700 (4.7% of reference drug budget) in 2013. Assuming that 10% of patients use standard AED therapy plus lacosamide, the budget impact of adopting adjunctive therapy with lacosamide is around €800,000-900,000 per year (or 16.7% of the reference drug budget).

CONCLUSIONS

Adjunctive therapy with lacosamide would raise drug spending for this patient population by as much as 16.7% per year. However, this budget impact analysis did not consider the fact that lacosamide reduces costs of seizure management and withdrawal. The literature suggests that, if savings in other healthcare costs are taken into account, adjunctive therapy with lacosamide may be cost saving.

Once-daily extended-release levetiracetam as adjunctive treatment of partial-onset seizures in patients with epilepsy: a double-blind, randomized, placebo-controlled trial

PURPOSE

Double-blind randomized trial to assess efficacy and tolerability of once-daily extended-release levetiracetam (LEV XR) tablets (2 x 500 mg) as add-on therapy in patients (12-70 years old) with partial-onset seizures (POS) refractory to one to three antiepileptic drugs.

METHODS

After an 8-week prospective baseline-period, eligible patients were randomized (1:1) to once-daily LEV XR 1,000 mg/day or placebo for 12 weeks. Evaluations included changes from baseline in POS-frequency/week, responders (>or=50% reduction in POS-frequency/week), seizure-freedom, adverse events, laboratory tests, physical and neurologic examinations, vital signs, body-weight, and 12-lead electrocardiogram.

RESULTS

Of 188 patients screened, 158 were randomized (intention-to-treat population): LEV XR (n = 79) or placebo (n = 79). Seventy-one (89.9%) LEV XR and 72 (91.1%) placebo patients completed the trial. Median POS-frequency/week reduction was 46.1% on LEV XR and 33.4% on placebo. Estimated reduction with LEV XR over placebo was 14.4% (p = 0.038). Thirty-four (43%) LEV XR and 23 (29.1%) placebo patients experienced >or=50% reduction in POS-frequency/week. Eight (10.1%) patients receiving LEV XR and one (1.3%) receiving placebo were free of POS during the 12-week treatment period. Forty-one (53.2%) LEV XR and 43 (54.4%) placebo patients reported >or=1 adverse event. Adverse events reported with an incidence >5% and seen more often with LEV XR than with placebo were somnolence, influenza, irritability, nasopharyngitis, dizziness, and nausea.

DISCUSSION

Once-daily LEV XR 1,000 mg was effective and well-tolerated as adjunct therapy in patients with POS. Ten percent of patients randomized to LEV XR experienced freedom from POS. These results support the clinical value of this new LEV XR formulation.

Levetiracetam in the treatment of epilepsy

Epilepsy is a common chronic disorder that requires long-term antiepileptic drug therapy. Approximately one half of patients fail the initial antiepileptic drug and about 35% are refractory to medical therapy, highlighting the continued need for more effective and better tolerated drugs. Levetiracetam is an antiepileptic drug marketed since 2000. Its novel mechanism of action is modulation of synaptic neurotransmitter release through binding to the synaptic vesicle protein SV2A in the brain. Its pharmacokinetic advantages include rapid and almost complete absorption, minimal insignificant binding to plasma protein, absence of enzyme induction, absence of interactions with other drugs, and partial metabolism outside the liver. The availability of an intravenous preparation is yet another advantage. It has been demonstrated effective as adjunctive therapy for refractory partial-onset seizures, primary generalized tonic-clonic seizures, and myoclonic seizures of juvenile myoclonic epilepsy. In addition, it was found equivalent to controlled release carbamazepine as first-line therapy for partial-onset seizures, both in efficacy and tolerability. Its main adverse effects in randomized adjunctive trials in adults have been somnolence, asthenia, infection, and dizziness. In children, the behavioral adverse effects of hostility and nervousness were also noted. Levetiracetam is an important addition to the treatment of epilepsy.

Evidence for a rapid action of levetiracetam compared to topiramate in refractory partial epilepsy

The objective of this observational study was to compare the efficacy of levetiracetam and topiramate during the first 15 days of add-on treatment in adults with refractory partial epilepsy. Two cohorts of patients with > or =3 simple or complex partial seizures with or without secondary generalisation per month over an 8-week baseline period received levetiracetam or topiramate in two distinct phases, in addition to standard antiepileptic treatment. During the first 15 days of the therapy, levetiracetam was added at the dosage of 250 mg b.i.d. or topiramate at 25mg o.i.d. Efficacy parameters included number of seizure-free days (SFDs), mean and percent reduction in seizure frequency (in general and by type), and number of seizure-free patients in the first 15 days of treatment compared to last 15 days of the baseline period. Sixty-one patients received levetiracetam and 61 topiramate. The general characteristics of the two treatment groups were similar. The total number of SFDs during 15 days before treatment was 637 with levetiracetam and 621 with topiramate; in the 15-day evaluation period the SFDs increased to 748 (17.4%) and 668 (7.6%), respectively (ANOVA, p<0.05). Twenty-six patients (42.6%) taking levetiracetam were seizure free compared to 10 (16.4%) receiving topiramate (chi-square, p=0.003). This open-label non-controlled study suggests an early efficacy of levetiracetam as add-on therapy in patients with refractory partial epilepsy: these results appear to confirm previous indications of a rapid onset of action and seem to suggest first evaluation of the patient at the dose of 500 mg/day before increasing to the considered minimum standard dose of 1000 mg/day, as some patients could respond to the starting dose.

Fast and Sustained Efficacy of Levetiracetam during Titration and the First 3 Months of Treatment in Refractory Epilepsy

PURPOSE

To investigate whether the efficacy of levetiracetam (LEV) is sustained in adult patients with refractory partial seizures over a 3-month period.

METHODS

Treatment effect was assessed in a post hoc analysis by determining the proportion of seizure-free days during each week of a 3-month period after the initiation of treatment. Pooled data from three randomized, double-blind, placebo-controlled trials (n = 883) were analyzed.

RESULTS

The mean proportion of seizure-free days was greater in the LEV group than in the placebo group. The difference, which was statistically significant, was observed as early as the first week after the initiation of treatment. It was higher in the first week of treatment and subsequently was maintained for each week over the 3-month period (p < 0.001 or p = 0.002 at each time point). Patients in the LEV group had on average 74% to 81% days each week without any seizure, compared with 69% to 72% in the placebo group.

CONCLUSIONS

LEV is efficient in controlling seizures from the first week of drug initiation, during uptitration, and throughout the first 3 months of treatment. An interesting amplification of efficacy occurs in the first week of therapy, which is intriguing and warrants further investigation.

Rapid Onset of Action of Levetiracetam in Refractory Epilepsy Patients

PURPOSE

To investigate whether rapid achievement of levetiracetam (LEV) steady state is translated into an immediate measurable efficacy. The time to onset of action of LEV immediately after its initiation in adult patients with refractory partial seizures was analyzed.

METHODS

Treatment effect was assessed in a pooled analysis (n=883) from three randomized, double-blind, placebo-controlled add-on trials.

RESULTS

The increase in the proportion of seizure-free patients over baseline was 15, 17, and 17% for the first, second, and third day, respectively, for the LEV 1,000-mg group (all differences statistically significant; McNemar p value<0.001), whereas the increase was 7, 9, and 9% for the 333-mg LEV group (differences not significant). No major changes were observed for the placebo group. For differences in proportion of seizure-free patients between groups, the probability of being seizure free in the LEV groups was twofold higher than in the placebo group. For the 1,000-mg LEV group, odds ratios were 2.3, 2.5, and 2.7 for the first, second, and third day of therapy, respectively; all differences versus placebo were statistically significant (logistic regression p values, all <0.001). The addition of LEV significantly increased the proportion of patients without a seizure as of the first day of therapy. Each of the first 3 days, seizure freedom was twice as likely to occur with LEV 1,000 mg than with placebo.

CONCLUSIONS

Evidence of a rapid onset of action of LEV 1,000 mg was demonstrated through a significant increase in the proportion of seizure-free patients as of the first day of therapy.

Benefit-Risk Assessment of Levetiracetam in the Treatment of Partial Seizures

Levetiracetam is a novel antiepileptic drug that has been demonstrated as being effective in the management of partial seizures. It is rapidly and completely absorbed after oral administration and it is predominantly eliminated as unchanged drug in the urine. Its metabolism is independent of the cytochrome P450 enzyme system, nor does it induce cytochrome P450 enzymes. As a result of its pharmacokinetic features, levetiracetam has not been demonstrated to interact with other drugs in either direction. In double-blind, placebo-controlled trials, all the levetiracetam dosages tested were effective, including 1000 mg/day, 2000 mg/day and 3000 mg/day. The ineffective dose is not known. Efficacy seemed to be maintained in long-term studies, with no evidence of tolerance. In major double-blind, placebo-controlled trials discontinuation rates because of adverse events were 6.9-10.9% for levetiracetam-treated patients (all doses) compared with 5.3-8.6% for placebo-treated patients. The most common adverse events that differed between treatment groups and placebo control groups were somnolence, asthenia, dizziness and, in the US study, infection. Since levetiracetam was marketed, behavioural effects have been reported, namely irritability, agitation, anger and aggressive behaviour. These adverse effects are more likely in learning disabled individuals, those with prior psychiatric history and those with symptomatic generalised epilepsy. Overall, the risk has been estimated at 12-15%. Laboratory parameters overall seem to be not significantly affected by levetiracetam, although slight trends to lower white and red blood cell counts were detected in the studies. No organ toxicity has been described so far, with patient exposures exceeding 500,000. In summary, levetiracetam exhibits a very favourable safety profile in patients with partial onset seizures. Whereas somnolence, asthenia and dizziness were the most prominent adverse effects in clinical trials, behavioural adverse effects have generally been the most common reason for drug discontinuation in clinical practice.

Economic evaluation of levetiracetam as an add-on therapy in patients with refractory epilepsy

OBJECTIVES

This study provides the results of a cost-effectiveness analysis of levetiracetam as an adjunctive treatment for refractory epilepsy from the Canadian Ministry of Health perspective. The main objective is to estimate the expected cost-effectiveness ratio expressed as the incremental cost per seizure-free day gained when using levetiracetam. In addition, this study examines the potential savings that might result by reducing the number of surgical evaluations and surgery when using levetiracetam.

METHODS

A 1-year dose escalation decision-tree model comparing levetiracetam plus standard therapy with standard therapy alone was designed in order to combine probability, resource use and unit cost data (1999 Canadian dollars [$Can]). The short-term outcomes were derived from three phase III randomised, double-blind, placebo-controlled trials performed in 904 patients, aged 16-70 years, with at least 1 year history of epilepsy, two to four partial seizures per month, and receiving a maximum of two classic antiepileptic drugs.

RESULTS

The average gain in seizure-free days attributed to levetiracetam was 19 days per patient per year and the incremental cost-effectiveness ratio (ICER) for levetiracetam add-on in the base-case scenario was $Can80.7 per seizure-free day gained per patient per year. Moreover, when surgical investigation and surgery are considered in the model, the use of levetiracetam may be dominant, with substantial savings to the overall healthcare budget. All univariate sensitivity analyses show that the model was robust to the assumptions made.

CONCLUSIONS

The economic analysis presented in this paper suggests, given a wide range of assumptions, that the increased cost of treating patients (with refractory epilepsy) with levetiracetam may be partially offset by a reduction in other direct medical costs (from the Canadian Ministry of Health perspective), as a consequence of an increase in the number of seizure-free days. Moreover, potential cost savings may be foreseen when it is assumed that levetiracetam may reduce the number of candidates for surgical evaluation and surgery through a reduction of seizure frequency.