Potential for improved retention rate by personalized antiseizure medication selection: A register-based analysis

Narrative Review of Brivaracetam: Preclinical Profile and Clinical Benefits in the Treatment of Patients with Epilepsy

One third of patients with epilepsy will continue to have uncontrolled seizures despite treatment with antiseizure medications (ASMs). There is therefore a need to develop novel ASMs. Brivaracetam (BRV) is an ASM that was developed in a major drug discovery program aimed at identifying selective, high-affinity synaptic vesicle protein 2A (SV2A) ligands, the target molecule of levetiracetam. BRV binds to SV2A with 15- to 30-fold higher affinity and greater selectivity than levetiracetam. BRV has broad-spectrum antiseizure activity in animal models of epilepsy, a favorable pharmacokinetic profile, few clinically relevant drug-drug interactions, and rapid brain penetration. BRV is available in oral and intravenous formulations and can be initiated at target dose without titration. Efficacy and safety of adjunctive BRV (50-200 mg/day) treatment of focal-onset seizures was demonstrated in three pivotal phase III trials (NCT00490035/NCT00464269/NCT01261325), including in patients who had previously failed levetiracetam. Efficacy and safety of adjunctive BRV were also demonstrated in adult Asian patients with focal-onset seizures (NCT03083665). In several open-label trials (NCT00150800/NCT00175916/NCT01339559), long-term safety and tolerability of adjunctive BRV was established, with efficacy maintained for up to 14 years, with high retention rates. Evidence from daily clinical practice highlights BRV effectiveness and tolerability in specific epilepsy patient populations with high unmet needs: the elderly (≥ 65 years of age), children (< 16 years of age), patients with cognitive impairment, patients with psychiatric comorbid conditions, and patients with acquired epilepsy of specific etiologies (post-stroke epilepsy/brain tumor related epilepsy/traumatic brain injury-related epilepsy). Here, we review the preclinical profile and clinical benefits of BRV from pivotal trials and recently published evidence from daily clinical practice.

Comparing the efficacy of anti-seizure medications using matched cohorts on a large insurance claims database

Epilepsy is a severe chronic neurological disease affecting 60 million people worldwide. Primary treatment is with anti-seizure medicines (ASMs), but many patients continue to experience seizures. We used retrospective insurance claims data on 280,587 patients with uncontrolled epilepsy (UE), defined as status epilepticus, need for a rescue medicine, or admission or emergency visit for an epilepsy code. We conducted a computational risk ratio analysis between pairs of ASMs using a causal inference method, in order to match 1034 clinical factors and simulate randomization. Data was extracted from the MarketScan insurance claims Research Database records from 2011 to 2015. The cohort consisted of individuals over 18 years old with a diagnosis of epilepsy who took one of eight ASMs and had more than a year of history prior to the filling of the drug prescription. Seven ASM exposures were analyzed: topiramate, phenytoin, levetiracetam, gabapentin, lamotrigine, valproate, and carbamazepine or oxcarbazepine (treated as the same exposure). We calculated the risk ratio of UE between pairs of ASM after controlling for bias with inverse propensity weighting applied to 1034 factors, such as demographics, confounding illnesses, non-epileptic conditions treated by ASMs, etc. All ASMs exhibited a significant reduction in the prevalence of UE, but three drugs showed pair-wise differences compared to other ASMs. Topiramate consistently was associated with a lower risk of UE, with a mean risk ratio range of 0.68-0.93 (average 0.82, CI: 0.56-1.08). Phenytoin and levetiracetam were consistently associated with a higher risk of UE with mean risk ratio ranges of 1.11 to 1.47 (average 1.13, CI 0.98-1.65) and 1.15 to 1.43 (average 1.2, CI 0.72-1.69), respectively. Large-scale retrospective insurance claims data - combined with causal inference analysis - provides an opportunity to compare the effect of treatments in real-world data in populations 1,000-fold larger than those in typical randomized trials. Our causal analysis identified the clinically unexpected finding of topiramate as being associated with a lower risk of UE; and phenytoin and levetiracetam as associated with a higher risk of UE (compared to other studied drugs, not to baseline). However, we note that our data set for this study only used insurance claims events, which does not comprise actual seizure frequencies, nor a clear picture of side effects. Our results do not advocate for any change in practice but demonstrate that conclusions from large databases may differ from and supplement those of randomized trials and clinical practice and therefore may guide further investigation.

Antiseizure medication selection and retention for adult onset focal epilepsy in a Swedish health service region: A population-based cohort study

OBJECTIVE

Historically, approximately half of those with newly diagnosed epilepsy have responded to and tolerated the first antiseizure medication (ASM), but there are few contemporary real-world data. Third-generation ASMs have improved tolerability and are increasingly used according to prescription data. We aimed to describe current ASM selection and retention in adult onset focal epilepsy in western Sweden.

METHODS

A multicenter retrospective cohort study was performed at five public neurology care providers in western Sweden (nearly complete coverage in the area). We reviewed 2607 medical charts and included patients diagnosed with nongeneralized epilepsy after January 1, 2020 who had a seizure onset after age 25 years (presumed focal onset) and were started on ASM monotherapy.

RESULTS

A total of 542 patients (median age at seizure onset = 68 years, interquartile range = 52-77) were included. Most patients received levetiracetam (62%) or lamotrigine (35%), with levetiracetam being more common among men and those with structural causes or short epilepsy duration. During follow-up (median = 471.5 days), 463 patients (85%) remained on the first ASM. Fifty-nine (18%) patients discontinued levetiracetam, and 18 (10%) ended treatment with lamotrigine (p = .010), most commonly because of side effects. In a multivariable Cox regression model, the discontinuation risk was higher for levetiracetam than lamotrigine (adjusted hazard ratio = 2.01, 95% confidence interval = 1.16-3.51).

SIGNIFICANCE

Levetiracetam and lamotrigine were the dominating first ASMs for adult onset focal epilepsy in our region, indicating good awareness of problems with enzyme induction or teratogenicity of older drugs. The most striking finding is the high retention rates, perhaps reflecting a shift toward an older epilepsy population, higher tolerability of newer ASMs, or suboptimal follow-up. The finding that treatment retention differed among patients receiving levetiracetam and lamotrigine aligns with the recent SANAD II results. It suggests lamotrigine may be underutilized in our region and that education efforts are needed to ensure it is considered the first choice more often.

The pharmacological treatment of epilepsy in adults

The pharmacological treatment of epilepsy entails several critical decisions that need to be based on an individual careful risk-benefit analysis. These include when to initiate treatment and with which antiseizure medication (ASM). With more than 25 ASMs on the market, physicians have opportunities to tailor the treatment to individual patients´ needs. ASM selection is primarily based on the patient's type of epilepsy and spectrum of ASM efficacy, but several other factors must be considered. These include age, sex, comorbidities, and concomitant medications to mention the most important. Individual susceptibility to adverse drug effects, ease of use, costs, and personal preferences should also be taken into account. Once an ASM has been selected, the next step is to decide on an individual target maintenance dose and a titration scheme to reach this dose. When the clinical circumstances permit, a slow titration is generally preferred since it is associated with improved tolerability. The maintenance dose is adjusted based on the clinical response aiming at the lowest effective dose. Therapeutic drug monitoring can be of value in efforts to establish the optimal dose. If the first monotherapy fails to control seizures without significant adverse effects, the next step will be to gradually switch to an alternative monotherapy, or sometimes to add another ASM. If an add-on is considered, combining ASMs with different modes of action is usually recommended. Misdiagnosis of epilepsy, non-adherence and suboptimal dosing are frequent causes of treatment failure and should be excluded before a patient is regarded as drug-resistant. Other treatment modalities, including epilepsy surgery, neuromodulation, and dietary therapies, should be considered for truly drug-resistant patients. After some years of seizure freedom, the question of ASM withdrawal often arises. Although successful in many, withdrawal is also associated with risks and the decision needs to be based on careful risk-benefit analysis.

Selection and Continuation of Antiseizure Medication in Children With Epilepsy in Sweden From 2007 to 2020

BACKGROUND

Knowledge on antiseizure medication (ASM) use and retention for children with epilepsy is limited, partly because of extensive off-label use of newer drugs with limited registration. We used prescription data to study prescription patterns on a population-wide scale and compared the proportion of patients remaining on monotherapy of ASMs with and without formal indication for different age groups.

METHODS

A total of 14,681 individuals aged <18 years were included, using cross-referenced Swedish registers from 2007 to 2020. Kaplan-Meier retention rates were calculated for all ASMs. The most common pathways of the first three medications per patient were analyzed.

RESULTS

In children older than one month and up to age one year, monotherapy retention rates were the highest for oxcarbazepine, valproic acid, and carbamazepine. Among children aged one to five years, oxcarbazepine and levetiracetam were among ASMs that do not have a monotherapy indication in Sweden but still had high retention rates. In the age group five to 12 years, lamotrigine and oxcarbazepine had the highest retention rate. In males aged 12 to 18 years, valproic acid was the most common choice followed by lamotrigine, whereas lamotrigine was the first choice of ASM for females, exceeding the second and third most common options levetiracetam and oxcarbazepine by a factor of two and three, respectively.

CONCLUSION

Off-label medication is common in children with epilepsy but does not seem to be associated with lower retention. The restrictions regarding valproic acid for females of childbearing age seem to have been well implemented in Swedish neuropediatric care.

Incidence of and predictors for antiseizure medication gaps in Medicare beneficiaries with epilepsy: a retrospective cohort study

BACKGROUND

For the two-thirds of patients with epilepsy who achieve seizure remission on antiseizure medications (ASMs), patients and clinicians must weigh the pros and cons of long-term ASM treatment. However, little work has evaluated how often ASM discontinuation occurs in practice. We describe the incidence of and predictors for sustained ASM fill gaps to measure discontinuation in individuals potentially eligible for ASM withdrawal.

METHODS

This was a retrospective cohort of Medicare beneficiaries. We included patients with epilepsy by requiring International Classification of Diseases codes for epilepsy/convulsions plus at least one ASM prescription each year 2014-2016, and no acute visit for epilepsy 2014-2015 (i.e., potentially eligible for ASM discontinuation). The main outcome was the first day of a gap in ASM supply (30, 90, 180, or 360 days with no pills) in 2016-2018. We displayed cumulative incidence functions and identified predictors using Cox regressions.

RESULTS

Among 21,819 beneficiaries, 5191 (24%) had a 30-day gap, 1753 (8%) had a 90-day gap, 803 (4%) had a 180-day gap, and 381 (2%) had a 360-day gap. Predictors increasing the chance of a 180-day gap included number of unique medications in 2015 (hazard ratio [HR] 1.03 per medication, 95% confidence interval [CI] 1.01-1.05) and epileptologist prescribing physician (≥25% of that physician's visits for epilepsy; HR 2.37, 95% CI 1.39-4.03). Predictors decreasing the chance of a 180-day gap included Medicaid dual eligibility (HR 0.75, 95% CI 0.60-0.95), number of unique ASMs in 2015 (e.g., 2 versus 1: HR 0.37, 95% CI 0.30-0.45), and greater baseline adherence (> 80% versus ≤80% of days in 2015 with ASM pill supply: HR 0.38, 95% CI 0.32-0.44).

CONCLUSIONS

Sustained ASM gaps were rarer than current guidelines may suggest. Future work should further explore barriers and enablers of ASM discontinuation to understand the optimal discontinuation rate.

Big data analysis of ASM retention rates and expert ASM algorithm: a comparative study

Objective

Only 50% of patients with new‐onset epilepsy achieve seizure freedom with their first antiseizure medication (ASM). A growing body of data illustrates the complexity of predicting ASM response and tolerability, which is influenced by age, sex, and comorbidities. Randomized data with sufficient resolution for personalized medicine are unlikely to emerge. Two potential facilitators of ASM selection are big data using real‐world retention rates or algorithms based on expert opinion. We asked how these methods compare in adult‐onset focal epilepsy.

Methods

ASM retention rates were determined by cross‐referencing data from comprehensive Swedish registers for 37 643 individuals, with identified comorbidities. Eight fictive cases were created and expert advice was collected from the algorithm Epipick. We compared Epipick suggestions in representative patient subgroups, and determined whether ranking based on retention rate reflected expert advice.

Results

The Epipick algorithm suggested six ASM alternatives for younger patients and three ASM alternatives for older patients. In the real‐world data, retention rates for the ASMs ranked as best options by Epipick were high; 65%–72% for young patients and 71%–84% for older patients. The lowest retention rate for Epipick suggestions was 42%–56% in younger cases, and 70%–80% in older cases. The ASM with the best retention rate was generally recommended by Epipick.

Significance

We found a large overlap between expert advice and real‐world retention rates. Notably, Epipick did suggest some ASMs with more modest retention rates. Conversely, clearly inappropriate ASMs (not recommended by Epipick) had high retention rates in some cases, showing that decision systems should not rely indiscriminately on retention rates alone. In future clinical decision support systems, expert opinion and real‐world retention rates could work synergistically.