INTRODUCTION: Efficacy/tolerability of adjunctive brivaracetam (BRV) for focal-onset seizures (FOS) in patients aged ≥ 16 years was established in randomized controlled trials. This study aimed to evaluate the effectiveness of adjunctive BRV in patients (≥ 16 years) with FOS with/without focal to bilateral tonic-clonic seizures in daily clinical practice. METHODS: A 12-month, prospective, real-world, noninterventional study in nine European countries (EP0077/NCT02687711). BRV was prescribed per clinical practice and European Summary of Product Characteristics. Eligible patients had never received BRV before inclusion. Treating physicians made the decision to prescribe BRV, independently of study participation. Primary effectiveness outcome: BRV retention rate at 12 months
secondary effectiveness outcomes: 50% responder rate, seizure freedom. RESULTS: A total of 544 patients received ≥ 1 BRV dose (mean age: 43.6 years
52.8% female
mean time since diagnosis: 22.7 years). Patients had a mean of 7.3 lifetime antiseizure medications (ASMs) and median of 3.7 FOS/28 days during 3-month retrospective baseline. Median total ASM drug load (including BRV) was 3.0 at BRV initiation (n = 539) and 3.3 at study end (n = 314). At 12 months, 57.7% of 541 patients remained on BRV, 60.4% of 230 were responders (≥ 50% seizure reduction since baseline), and 13.8% of 269 were seizure-free since BRV initiation. Historical levetiracetam use appeared not to impact retention rate (56.6% of 320 and 59.3% of 221 patients with and without historical levetiracetam use, respectively). 36.0% of 544 patients had drug-related treatment-emergent adverse events (TEAEs), mostly (≥ 5% of patients) drug ineffective (11.4%) and seizure (6.3%). The three most common drug-related TEAEs leading to permanent BRV discontinuation (of 544 patients) were drug ineffective (10.1%), seizure (5.1%), and behavior disorder (3.3%). CONCLUSIONS: Adjunctive BRV was effective in clinical practice in patients with predominantly difficult-to-treat FOS, as shown by BRV retention rate of 57.7% at 12 months, which is in line with real-world retention rates for other new-generation ASMs.