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(61.6%) patients, most commonly (≥ 10% of patients) due to adverse event (18.3%), lack of efficacy (18.3%), and consent withdrawn (11.6%); the median time to discontinuation of BRV due to any reason was 358.5 days.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.