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

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. 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. 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. 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.