Abstracts

Rationale: Perampanel, a selective, noncompetitive AMPA receptor antagonist, is approved for adjunctive treatment of partial seizures with or without secondarily generalized seizures and for primary generalized tonic-clonic seizures in patients with epilepsy aged ≥12 years. Post-hoc analysis of trials showed that efficacy of perampanel varied by number of antiepileptic drugs (AEDs) at baseline. This study aims to assess the healthcare resource utilization (HRU) effect of perampanel by number of AEDs used at baseline. Methods: Health insurance claims database from Symphony Health Solutions, a large, nationally representative database covering ~260 million lives annually in the US receiving commercial, Medicare, or Medicaid insurances, was used to identify the study population of patients with ≥1 diagnosis of epilepsy or non-febrile convulsions, ≥12 years of age receiving ≥1 perampanel dispensing between 12/2012 and 11/2015 (first dispensing was termed as the index date), and ≥180 days of continuous observation during both pre- and post-perampanel periods. Patients were stratified by number of AED use during the 180-day pre-perampanel period into 1-2 and ≥3 AEDs. All-cause and epilepsy-related HRU were compared between the pre- and post-perampanel period using conditional Poisson regression models; results are presented as rate ratios (RR) and 95% confidence intervals (CI). Results: Of the 2,423 study sample, 1,268 had 1-2 and 1,155 had ≥3 AEDs at baseline. Both groups had similar demographic characteristics (Table 1). Perampanel was associated with significantly lower rates of all-cause and epilepsy-related HRU across both AED groups (Table 2). For the 1-2 AEDs group, the rate per 100 person-years was 33.9 vs. 44.1 (RR 0.81; 95% CI 0.70-0.94) for all-cause hospitalizations, and 1,076.5 vs. 1,265.0 (RR 0.86; 95% CI 0.83-0.88) for all-cause outpatient visits for the post- vs. pre-perampanel period. Similarly, epilepsy-related hospitalizations and outpatient visits were significantly lower in the post- vs. pre-period, with rates per 100 person-years of 20.7 vs. 26.1 (RR 0.82; 95% CI 0.68-0.99) and 296.6 vs. 356.6 (RR 0.83; 95% CI 0.79-0.87), respectively. Similar trends were observed for the ≥3 AEDs group; the rates of all-cause and epilepsy-related hospitalizations and outpatient visits were significantly lower in the post- vs. pre-period. Noteworthy, a substantial reduction in the hospitalization rate for status epilepticus in the post-perampanel period was observed in the ≥3 AEDs group, with rates per 100 person-years of 2.3 (post) vs. 7.2 (pre) (RR 0.32; 95% CI 0.20-0.50). Conclusions: Based on this analysis, perampanel was associated with significant decreases in all-cause and epilepsy-related HRU regardless of the number of baseline AEDs used.  Funding: Eisai, Inc.