To assess perampanel (PER) when used as early add-on therapy in everyday clinical practice.

PER is an anti-seizure medication (ASM) for focal-onset seizures, with or without focal to bilateral tonic-clonic seizures, and generalized tonic-clonic seizures. Information on using PER as early add-on in clinical practice is currently limited.

Patients treated with PER for focal-onset and/or generalized-onset seizures were identified from a pooled analysis of 44 clinical practice studies. Data were compared for patients treated with PER as early add-on therapy versus late add-on therapy (as defined by each individual study). Retention was assessed after 3, 6 and 12 months of PER treatment. Effectiveness assessments included responder rate (≥50% seizure frequency reduction) and seizure freedom rate (no seizures since at least the prior visit). Safety and tolerability were assessed by evaluating adverse events (AEs).  

A total of 2532 patients were treated with PER as early (n=632) or late (n=1900) add-on therapy; median number of ASMs were 1 and 3 at baseline, respectively. Retention rates were significantly higher for patients treated with early versus late add-on therapy at all timepoints (Month 12: 77.1% vs. 61.8%; p<0.001). At last visit (last observation carried forward), seizure freedom rate was significantly higher in patients treated with early versus late add-on therapy (40.1% vs. 8.7%; p<0.001), as was responder rate (73.0% vs. 36.4%; p<0.001). Incidence of AEs was significantly lower for patients treated with early versus late add-on therapy (41.8% vs. 54.5%; p<0.001), as was proportion of patients with psychiatric AEs (18.3% vs. 22.2%; p=0.046), and the rate of discontinuation due to AEs at 12 months (15.0% vs. 18.7%; p=0.045).

PER was significantly more effective and better tolerated when used as early versus late add-on therapy to treat patients in everyday clinical practice.