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 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. Two hundred and eighty-four patients reported FBTCS during baseline (core trials) and were included in the Efficacy Set. 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. Patients (≥ 16 years) were included in this post hoc analysis if they were randomized to BRV or placebo in double-blind, placebo-controlled (N01252, N01253, N01358 core) trials, and received adjunctive BRV in the corresponding long-term follow-up (N01125, N01199, N01379 ) trials, and reported FBTCS during the 8-week prospective baseline (core trial). 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).