Efficacy and Tolerability of Adjunctive Brivaracetam in Patients with Focal-Onset Seizures on Specific Concomitant Antiseizure Medications: Pooled Analysis of Double-Blind, Placebo-Controlled Trials

Abstract

Introduction: This article aimed to assess the efficacy and tolerability of adjunctive brivaracetam (BRV) in adults with focal-onset seizures on specific concomitant antiseizure medications (ASMs) taken as part of their treatment regimen.

Methods: This was a post hoc analysis of pooled data from double-blind, placebo-controlled trials (N01252/NCT00490035, N01253/NCT00464269, and N01358/NCT01261325) in patients with uncontrolled focal-onset seizures randomized to BRV (50-200 mg/day) or placebo on the most common concomitant ASMs at trial initiation.

Results: Nine concomitant ASMs were analyzed: carbamazepine (CBZ), lamotrigine (LTG), valproate (VPA), oxcarbazepine (OXC), topiramate (TPM), phenytoin (PHT), lacosamide (LCM), clobazam (CLB), and phenobarbital (PHB). Reduction over placebo in focal-onset seizure frequency per 28 days with BRV ranged from 11.7% (concomitant OXC) to 33.5% (concomitant PHB). The median percentage reduction from baseline in focal-onset seizure frequency per 28 days ranged from 25.5% to 42.8% in patients on BRV (placebo 4.4-21.2%); 50% responder rates ranged from 31.9% to 44.9% in patients on BRV (placebo 11.4-25.2%). In patients on BRV, seizure freedom ranged from 1.4% (concomitant PHT) to 12.5% (concomitant LCM); seizure freedom ranged from 0% to 1.2% in patients on placebo. All efficacy endpoints analyzed were consistently numerically higher in patients on BRV versus placebo. The overall incidence of treatment-emergent adverse events (TEAEs) was generally similar across subgroups by specific concomitant ASMs in patients on BRV (range 60.8-74.5%) or placebo (range 53.8-66.7%). Drug-related TEAEs were numerically higher across all subgroups by concomitant ASM in patients on BRV (range 35.2-48.3%) versus placebo (range 23.9-37.1%). Discontinuations due to TEAEs ranged from 2.9% to 13.3% in patients on BRV and was 0-5.7% for patients taking placebo across subgroups.

Conclusion: BRV was efficacious and well tolerated regardless of the specific concomitant ASMs used as part of their treatment regimen. These data show that in patients with focal-onset seizures, BRV provides additional efficacy to a broad range of ASMs.

Keywords: Antiseizure medication; Brivaracetam; Efficacy; Epilepsy; Focal-onset seizures; Tolerability.

Fig. 1

Efficacy by specific concomitant antiseizure medications at trial drug initiation: a median percentage reduction from baseline in focal-onset seizures per 28 days, b 50% responder rate^a, and c seizure freedom (all seizure types)^b (efficacy population). ^aFor the 50% responder rates (patients with a ≥ 50% reduction from baseline in focal-onset seizure frequency), p values are for odds ratios of brivaracetam versus placebo. ^bPatients were classified as seizure free if they completed the treatment period, did not report seizures of any type (including focal-onset seizures, generalized seizures, and unclassified seizures), and there were no missed days in their seizure diary. BRV brivaracetam, CBZ carbamazepine, CI confidence interval, CLB clobazam, LCM lacosamide, LTG lamotrigine, OXC oxcarbazepine, PBO placebo, PHB phenobarbital, PHT phenytoin, TPM topiramate, VPA valproate