Abstracts

Rationale: Intellectual disability (ID) is a common comorbidity in epilepsy, but epilepsy patients with ID are usually excluded from epilepsy clinical trials. Real-world evidence from clinical practice studies is therefore required to inform treatment decisions in this patient group. Perampanel (PER) is a once-daily oral anti-seizure medication for focal-onset seizures, with or without focal to bilateral tonic-clonic seizures, and generalized tonic-clonic seizures. The purpose of this study was to assess PER when used in everyday clinical practice to treat epilepsy patients with ID.

Methods: Patients with ID treated with PER for focal-onset and/or generalized-onset seizures were identified from a pooled analysis of 44 clinical practice studies/work groups. Data were compared for patients with versus without ID. Retention was assessed after 3, 6 and 12 months. Effectiveness assessments comprised responder rate (≥ 50% seizure frequency reduction), seizure freedom rate (no seizures since at least the prior visit), and the proportions of patients with unchanged or worsening seizure frequency. Safety and tolerability were assessed by evaluating adverse events (AEs), psychiatric AEs, and AEs leading to discontinuation.

Results: Overall, 735 patients with ID and 1890 patients without ID were identified. Retention was assessed for 2471 patients (with ID, n=701; without ID, n=1770); effectiveness for 2121 patients (with ID, n=627; without ID, n=1494); and safety/tolerability for 2223 patients (with ID, n=655; without ID, n=1568). Retention rates at 3, 6 and 12 months were similar in patients with and without ID (Figure 1). Reasons for discontinuation in patients with ID were AEs (13.8%), lack of efficacy (10.0%), and both AEs and lack of efficacy (5.6%). Mean time under PER treatment was similar for patients with versus without ID (10.5 vs. 10.6 months; p=not significant). At the last visit (last observation carried forward), responder and seizure freedom rates were significantly lower in patients with versus without ID, and the proportion of patients with unchanged seizure frequency was significantly higher in patients with versus without ID; the proportion of patients with worsening seizure frequency was similar between groups (Figure 2). Incidence of AEs was similar in patients with versus without ID (51.5% vs. 54.7%; p=not significant), as was rate of discontinuation due to AEs at 12 months (19.5% vs. 19.4%; p=not significant). The incidence of psychiatric AEs was significantly higher in patients with versus without ID (27.1% vs. 21.2%; p=0.003). The most common AEs ( >5% of patients) in patients with ID were dizziness/vertigo (10.4%), irritability (10.2%), somnolence (9.3%) and behavioural disorders (7.5%).

Conclusions: PER was effective when used to treat epilepsy patients with ID, although not as effective as in patients without ID which may reflect the difficulty of treating this patient population. PER was generally well tolerated in patients with ID; the incidence of psychiatric AEs was higher than in those without ID.

Funding: Please list any funding that was received in support of this abstract.: Supported by Eisai.