Safety, tolerability, and efficacy of brivaracetam as adjunctive therapy in patients with focal seizures, generalized onset seizures, or Unverricht-Lundborg disease: An open-label, long-term follow-up trial

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.

Efficacy, safety, and tolerability of adjunctive brivaracetam in adult Asian patients with uncontrolled focal-onset seizures: A phase III randomized, double-blind, placebo-controlled trial

OBJECTIVE

Evaluate efficacy, safety, and tolerability of adjunctive brivaracetam (BRV) in adult Asian patients with focal-onset seizures (FOS).

METHODS

Phase III, randomized, double-blind, placebo-controlled study (EP0083; NCT03083665) evaluating BRV 50 mg/day and 200 mg/day in patients (≥16-80 years) with FOS with/without secondary generalization (focal to bilateral tonic-clonic seizures) despite current treatment with 1 or 2 concomitant antiseizure medications. Following an 8-week baseline, patients were randomized 1:1:1 to placebo, BRV 50 mg/day, or BRV 200 mg/day, and entered a 12-week treatment period. Efficacy outcomes: percent reduction over placebo in 28-day FOS frequency (primary); 50% responder rate in FOS frequency; median percent reduction in FOS frequency from baseline; seizure freedom during treatment period (secondary). Primary safety endpoints: incidences of treatment-emergent adverse events (TEAEs); TEAEs leading to discontinuation; serious TEAEs.

RESULTS

In this study, 448/449 randomized patients (mean age, 34.5 years; 53.8% female) received ≥1 dose of study medication (placebo/BRV 50 mg/BRV 200 mg/day: n = 149/151/148). Percent reduction over placebo in 28-day adjusted FOS frequency was 24.5% (p = 0.0005) and 33.4% (p < 0.0001) with BRV 50 mg/day and 200 mg/day, respectively, 50% responder rate was 19.0%, 41.1%, and 49.3% with placebo, BRV 50 mg/day, and BRV 200 mg/day, respectively (p < 0.0001 for both BRV groups vs. placebo). Median percent reduction in FOS frequency from baseline was 21.3%/38.9%/46.7% in patients on placebo/BRV 50 mg/BRV 200 mg/day, respectively. Overall, 0, 7 (4.6%), and 10 (6.8%) patients were classified as seizure-free during the treatment period on placebo, BRV 50 mg/day, and BRV 200 mg/day, respectively (p = 0.0146/p = 0.0017 for BRV 50 mg/200 mg/day vs. placebo, respectively). TEAE incidences were similar between patients on placebo (58.4%) and all patients receiving BRV (58.5%); TEAE incidences for BRV 50 mg/day and BRV 200 mg/day were 57.0% and 60.1%, respectively. Overall, 0.7% of patients on placebo and 2.0% of all patients on BRV reported serious TEAEs (incidences for BRV 50 mg/day and BRV 200 mg/day were 1.3% and 2.7%, respectively), 20.1% of patients on placebo and 33.1% of all patients on BRV reported drug-related TEAEs (incidences for BRV 50 mg/day and BRV 200 mg/day were 26.5% and 39.9%, respectively), and 4.7% of patients on placebo and 3.0% of all patients on BRV discontinued due to TEAEs (discontinuation incidences for BRV 50 mg/day and BRV 200 mg/day were 2.6% and 3.4%, respectively).

SIGNIFICANCE

Adjunctive BRV was efficacious and well tolerated in adult Asian patients with FOS. Efficacy and safety profiles were consistent with BRV studies in predominantly non-Asian populations.

PLAIN LANGUAGE SUMMARY

Brivaracetam is used to treat partial or focal seizures in people with epilepsy. Most studies with brivaracetam tablets have involved people from non-Asian racial backgrounds. In this study, 449 Asian adults with epilepsy took part. One third took 50 mg of brivaracetam, one third took 200 mg of brivaracetam, and one third took a placebo each day for 12 weeks. On average, those who took brivaracetam had fewer seizures than those given the placebo. Most of the side effects were mild and the number and type of side effects seen were as expected for this medication.

Progressive Myoclonus Epilepsy: A Scoping Review of Diagnostic, Phenotypic and Therapeutic Advances

The progressive myoclonus epilepsies (PME) are a diverse group of disorders that feature both myoclonus and seizures that worsen gradually over a variable timeframe. While each of the disorders is individually rare, they collectively make up a non-trivial portion of the complex epilepsy and myoclonus cases that are seen in tertiary care centers. The last decade has seen substantial progress in our understanding of the pathophysiology, diagnosis, prognosis, and, in select disorders, therapies of these diseases. In this scoping review, we examine English language publications from the past decade that address diagnostic, phenotypic, and therapeutic advances in all PMEs. We then highlight the major lessons that have been learned and point out avenues for future investigation that seem promising.

Retention, efficacy, tolerability, and quality of life during long-term adjunctive brivaracetam treatment by number of lifetime antiseizure medications: A post hoc analysis of phase 3 trials in adults with focal seizures

OBJECTIVE

To evaluate long-term retention, reasons for discontinuation, efficacy, tolerability, and health-related quality of life (HRQOL) during adjunctive brivaracetam (BRV) treatment in adults with focal seizures by number of lifetime antiseizure medications (ASMs).

METHODS

Post hoc analyses of a randomized, double-blind, placebo-controlled trial (N01358; NCT01261325) and corresponding open-label extension (OLE) (N01379; NCT01339559) of adjunctive BRV in adults (16-80 years of age) with focal seizures. Outcomes were assessed from the first day of BRV treatment in the double-blind (patients randomized to BRV) or open-label trial (patients randomized to placebo) by number of lifetime ASMs (1-2, 3-4, 5-6, or ≥ 7). Lifetime ASMs were defined as previous (stopped before BRV initiation) and concomitant ASMs at BRV initiation.

RESULTS

Seven hundred and forty patients received adjunctive BRV (safety set [SS]; median modal dose: 200 mg/day [N = 737]; median treatment duration: 2.67 years), of whom 13.8 % had 1-2, 20.8 % had 3-4, 21.1 % had 5-6 and 44.3 % had ≥7 lifetime ASMs. Patients with a higher number of lifetime ASMs had a younger age at epilepsy onset, longer epilepsy duration, and higher baseline seizure frequency. Kaplan-Meier estimated retention on BRV at 12 (83.2-65.9 %) and 36 months (63.0-44.1 %) was highest in patients with 1-2 lifetime ASMs and decreased with the number of lifetime ASMs. The estimated proportions of patients who discontinued BRV due to lack of efficacy or treatment-emergent adverse events (TEAEs) increased with the number of lifetime ASMs. Efficacy analyses included seven hundred and thirty eight patients (intention-to-treat set [ITT]). Median percentage reductions from baseline in focal seizure frequency/28 days (76.3-39.6 %), 50 % responder rates (66.7-39.8 %), 75 % responder rates (51.0-19.6 %), and continuous seizure freedom for ≥12 months at any time during BRV treatment (35.3-6.1 %) were highest in patients with 1-2 lifetime ASMs and decreased by the number of lifetime ASMs. The overall incidence of TEAEs (SS) was generally similar in each lifetime ASM subgroup (84.4-90.5 %). Discontinuations due to TEAEs increased with the number of lifetime ASMs (7.8-20.1 %). The greatest improvements in QOLIE-31-P scores occurred in the Seizure Worry and Daily Activities/Social Function subscales, with no clear pattern by the number of lifetime ASMs at 12 months and with the highest improvement in patients with 1-2 lifetime ASMs at 24 months. At 24 months, the Hospital Anxiety and Depression Scale (HADS) Anxiety subscale scores improved in patients (SS) with 1-2 and 3-4 lifetime ASMs. HADS Depression subscale scores were generally stable independent of the number of lifetime ASMs.

CONCLUSIONS

The balance between efficacy, tolerability, and HRQOL was most favorable in patients with focal seizures who had been exposed to one or two ASMs before BRV initiation. However, patients exposed to ≥7 ASMs before BRV initiation also benefitted from long-term adjunctive BRV treatment.

BRIVEST: A 'real-world' observational, single-centre study investigating the efficacy, safety and tolerability of Brivaracetam

OBJECTIVE

Via measures of efficacy, tolerability, and safety, this open-label, single-center study assessed the overall effectiveness of Brivaracetam (BRV) for the treatment of epilepsy in the context of 'real-world' clinical practice.

METHODS

Unselected consecutive patients were recruited and stratified into 3 cohorts with either fully prospective, fully retrospective or mixed data collection, dependent on whether their BRV prescriptions were historical, current, or pending. Prospective data were obtained at baseline, 3 and 6 months, and at 6-month intervals thereafter, from patient interviews and seizure diaries, and retrospective data from medical records. Efficacy variables were derived from seizure-related changes, and tolerability and safety variables from reported treatment-emergent adverse events (TEAEs), BRV withdrawal, and changes to questionnaire scores. Additionally, we investigated treatment outcomes for those with previous levetiracetam (LEV) use, a history of psychiatric comorbidity, a learning disability, and of older age.

RESULTS

One hundred and nine patients (58.7% female, mean age 42 years, range: 18 to 72) were included, 59 with prospective follow-up for a minimum of 6 (47 patients, excluding those who withdrew) and a maximum of 24 months (2 patients). Of the full cohort, 87.2% had drug-resistant epilepsy. Retention: At the study end, the median treatment duration was 384 days (range: 6 to 1514 days), and BRV retention was 68.8%. Kaplan-Meier survival functions predicted retention rates of 74.0% and 70.0% at 6 and 12 months respectively.

EFFICACY

At the last follow-up, there was a ≥ 50% responder rate of 30.8%, with 12.1% seizure-free. Seizure frequency categories improved in 31.4% of patients, remained the same in 44.2%, and worsened in 24.4%. Monthly tonic-clonic seizure frequency had significantly decreased, and of those reporting these seizures, 58.3% showed reductions and 25.0% showed complete tonic-clonic seizure freedom.

TOLERABILITY

91.7% of patients reported at least 1 TEAE, with fatigue (30.3%), irritability (29.4%), and depression/low mood (28.4%) as the most common. Only 58.4% of all TEAEs were persistent. Brivaracetam discontinuation due to side effects occurred in 27.5% of the cohort. Depression and anxiety scores remained stable over time, and quality-of-life scores improved. Subgroups: Measures of BRV efficacy and tolerability did not differ according to previous LEV exposure. Tolerability profiles of those with learning disabilities, histories of psychiatric comorbidities, and older age did not greatly differ from the rest of the cohort. Of note, specific history of depression predicted the reporting of suicidal ideation.

CONCLUSION

The BRIVEST study provides real-world evidence of the effectiveness of BRV, suggesting that neither drug-resistant epilepsy nor previous LEV failure should preclude its use. Furthermore, BRV appears to be well-tolerated, even among those from vulnerable patient populations.

Significant improvements in SEIzure interVAL (time between seizure clusters) across time in patients treated with diazepam nasal spray as intermittent rescue therapy for seizure clusters

OBJECTIVE

Intermittent rescue therapy may be used for seizure clusters, which are clinical emergencies that may persist ≥24 h and increase risk of status epilepticus, emergency room visits, and reduced quality of life for patients with epilepsy. Beyond effectiveness for aborting seizure clusters, no data exist on how intermittent rescue therapy may impact the long-term natural course of seizure clusters. This novel analysis explores SEIzure interVAL (SEIVAL; time between seizure clusters) in patients from a long-term safety study of diazepam nasal spray (Valtoco) to assess SEIVAL changes with intermittent rescue therapy across time.

METHODS

Patients were aged 6-65 years. Age- and weight-based doses of diazepam nasal spray were administered during a 12-month treatment period with an optional follow-up period. SEIVAL was evaluated in patients receiving two or more doses of diazepam nasal spray using 90-day periods.

RESULTS

Of 163 treated patients, 151 had one or more SEIVALs. One hundred twenty had SEIVALs in Period 1 and one or more other periods. An increase in SEIVAL was noted from Period 1 compared with all subsequent periods (p ≤ .001). A consistent cohort (n = 76) had one or more SEIVALs in each of Periods 1-4 (360 days); mean SEIVALs increased significantly (p < .01) from 12.2 days (Period 1) to 25.7 days (Period 4). Similar SEIVAL patterns occurred when repeat doses within a seizure cluster were eliminated and irrespective of age group, treatment duration, and change to concomitant medications. In adults, Quality of Life in Epilepsy scores were maintained with increased SEIVALs.

SIGNIFICANCE

Across 12 months, increases in SEIVAL were demonstrated in patients using diazepam nasal spray for seizure cluster treatment in a phase 3 safety study. Increased time between seizure clusters may reflect a previously unrecognized beneficial effect of intermittent rescue therapy. These results generate a range of biological and behavioral hypotheses and warrant exploration of the impact of intermittent rescue therapy.

Long-term safety of adjunctive cenobamate in patients with uncontrolled focal seizures: Open-label extension of a randomized clinical study

Objective

This study was undertaken to examine long‐term (up to 7.8 years) retention rate, safety, and tolerability of the antiseizure medication (ASM) cenobamate as adjunctive treatment in the open‐label extension (OLE) of study YKP3089C013 (C013; ClinicalTrials.gov: NCT01397968).

Methods

Patients who completed the 12‐week, multicenter, multinational, double‐blind, randomized, placebo‐controlled C013 study, which examined adjunctive cenobamate treatment of adults with uncontrolled focal seizures, were eligible to enroll in the OLE. During the OLE, dose adjustments of cenobamate and concomitant ASMs were allowed. Safety assessments included frequency of treatment‐emergent adverse events (TEAEs) and serious TEAEs, TEAE severity, and TEAEs leading to discontinuation. Probability of patient continuation in the OLE was examined using a Kaplan–Meier analysis.

Results

One hundred forty‐nine patients entered the OLE (median duration of cenobamate treatment = 6.25 years). As of the data cutoff, 57% of patients (85/149) remained in the OLE (median treatment duration = 6.8 years, range = 6.4–7.8 years). The median modal daily cenobamate dose was 200 mg (range = 50–400 mg). The probability of treatment continuation at 1–6 years of cenobamate treatment was 73%, 67%, 63%, 61%, 60%, and 59%, respectively. Among patients who continued at 1 year (n = 107), the probability of continuing at Years 2–5 was 92%, 87%, 83%, and 82%. The most common discontinuation reasons were patient withdrawal (19.5%, 29/149), adverse event (10.1%, 15/149), and lack of efficacy (5.4%, 8/149). TEAEs leading to discontinuation in 1% or more of patients were fatigue (1.3%, 2/149), ataxia (1.3%, 2/149), and memory impairment or amnesia (1.3%, 2/149). Dizziness (32.9%, 49/149), headache (26.8%, 40/149), and somnolence (21.5%, 32/149) were the most frequently reported TEAEs and were primarily mild or moderate in severity.

Significance

Long‐term retention in the C013 OLE study demonstrated sustained safety and tolerability of adjunctive cenobamate treatment up to 7.8 years in adults with treatment‐resistant focal seizures taking one to three ASMs.

Long-term efficacy and tolerability of adjunctive brivaracetam in adults with focal to bilateral tonic-clonic (secondary generalized) seizures: Post hoc pooled analysis

This post hoc analysis was conducted to evaluate the efficacy, tolerability, and health-related quality of life during long-term adjunctive brivaracetam (BRV) treatment in adult patients with focal to bilateral tonic-clonic seizures (FBTCS). Patients (≥ 16 years) were included in this post hoc analysis if they were randomized to BRV or placebo in double-blind, placebo-controlled (N01252 [NCT00490035], N01253 [NCT00464269], N01358 [NCT01261325]; core) trials, and received adjunctive BRV in the corresponding long-term follow-up (N01125 [NCT00175916], N01199 [NCT00150800], N01379 [NCT01339559]) trials, and reported FBTCS during the 8-week prospective baseline (core trial). Efficacy (concomitant levetiracetam excluded) and tolerability (concomitant levetiracetam included) were assessed from the first day of BRV in patients who initiated BRV at 50-200 mg/day. Two hundred and eighty-four patients reported FBTCS during baseline (core trials) and were included in the Efficacy Set. Patients (mean age of 37.0 years; 51.8% male; mean epilepsy duration of 22.4 years; median baseline frequency of 2.8 FBTCS per 28 days) received BRV for a median treatment duration of 2.5 years (range< 0.1-11.3) at a median modal dose of 150 mg/day. BRV was discontinued by 175 (61.6%) patients, most commonly (≥ 10% of patients) due to adverse event (18.3%), lack of efficacy (18.3%), and consent withdrawn (11.6%); the median time to discontinuation of BRV due to any reason was 358.5 days. The Kaplan-Meier (KM)-estimated retention on BRV at 1, 3, and 5 years, were 69.3%, 48.2%, and 37.3%, respectively. The KM-estimated proportion of patients not discontinuing BRV due to lack of efficacy or adverse event were 80.0%, 63.9%, and 57.2% at 1, 3, and 5 years, respectively. Overall, the median percentage reduction in FBTCS frequency from baseline was 76.2%, and the 50% and 75% responder rates for FBTCS were 68.7% and 50.7%, respectively, which were sustained over time across completer cohorts. Sustained 50%, 75%, and 100% response in FBTCS from day 1 of adjunctive BRV treatment during the entire first year was estimated for 32.5%, 21.1%, and 15.0% of patients, respectively (KM analysis), and showed maintenance or improvement in the response to BRV over time. For patients with ≥ 1 year of BRV exposure, 51.3% were free from FBTCS for ≥ 1 year during any time of the treatment period, and 22.8% of patients did not report FBTCS during the first year from the first day of treatment. Clinically meaningful improvements in total Patient Weighted Quality of Life in Epilepsy Inventory-Form 31 (QOLIE-31-P) score were reported by 43.6% and 46.4% of patients after 1 and 2 years of treatment, respectively. The largest improvements in the QOLIE-31-P score, with > 50% of patients reporting a clinically meaningful improvement, were observed in the seizure worry and daily activities/social functioning subscales after 1 and 2 years of BRV treatment. Overall, 278/313 (88.8%; Safety Set) patients reported at least one treatment-emergent adverse event (TEAE), 170 (54.3%) had a drug-related TEAE, 88 (28.1%) had a serious TEAE, and 55 (17.6%) discontinued BRV due to a TEAE. Overall, long-term adjunctive BRV was generally well tolerated and reduced the frequency of FBTCS in adults, with 22.8% of patients (who completed ≥ 1 year of treatment) not reporting any FBTCS during the first year from the first day of BRV treatment.