Abstracts

Rationale: Perampanel is approved as an adjunctive therapy for partial seizures with or without secondary generalization and for primary generalized tonic-clonic seizures in patients with epilepsy aged ≥12 years. Two small studies showed that perampanel as monotherapy reduced seizure frequency by ≥50%.1,2 This study aimed to assess impact of perampanel monotherapy on healthcare resource utilization (HRU). Methods: A pre-post study design was used to compare HRU before vs. after perampanel monotherapy initiation. A nationally representative claims database from Symphony Health Solutions, capturing ~75% of US population cross-sectionally, was used to identify the study population of patients ≥12 years with ≥1 diagnosis of epilepsy or non-febrile convulsions, ≥1 perampanel dispensing between 12/2012 and 11/2015 (first dispensing was termed the index date), and ≥180 days of continuous observation pre- and post-perampanel initiation. Perampanel monotherapy was defined as ≥60 consecutive days use without concomitant antiepileptic drugs (AEDs). Primary monotherapy was defined as initiating perampanel as monotherapy from index date; secondary monotherapy was defined as first initiating perampanel as an adjunctive therapy but later switching to perampanel monotherapy by discontinuing concomitant AEDs. Conditional Poisson regression models were used to compare all-cause and epilepsy-related HRU during the 180-day pre- vs. post-perampanel period for monotherapy overall and by primary and secondary monotherapy groups. Results are presented as rate ratios (RR) and 95% confidence intervals (CI). Results: A total of 49 perampanel monotherapy users were identified, consisting of 9 primary and 40 secondary monotherapy users, of 2,508 patients who met inclusion criteria. Mean post-perampanel observation was 473.2 days, with mean age of 44.6 (±18.9) years and 63.3% female. Perampanel as monotherapy was associated with lower rates of all-cause and epilepsy-related HRU (Table 1). For all-cause hospitalization, the rate per 100 person-years post- vs. pre-perampanel was 26.8 vs. 37.2 (RR 0.65; 95% CI 0.29-1.46). Epilepsy-related hospitalizations and outpatient visits were also lower post- vs. pre-perampanel, with rates per 100 person-years of 9.4 vs. 16.6 (RR 0.49; 95% CI 0.14-1.74) and 154.3 vs. 231.7 (RR 0.66; 95% CI 0.47-0.92), respectively. Similar trend of HRU reduction post-perampanel was observed in both primary and secondary monotherapy groups. While no results reached statistical significance due to small sample sizes, the rate reduction was consistently observed across HRU and monotherapy groups, particularly substantial in hospitalization rates. Conclusions: Results of this small hypothesis-generating study suggest perampanel as a primary or secondary monotherapy agent is associated with a decrease in all-cause and epilepsy-related HRU, especially in hospitalization rates. 1 Kwan P., et al. Evaluation of perampanel monotherapy in epilepsy: prospective open-label extension and retrospective uncontrolled studies. Poster presented at the 69th Annual Meeting of the American Academy of Neurology, Boston, MA, USA, April 22-28, 2017. 2 Gil-Nagel A., et al. A retrospective, multicenter study to investigate dosage, efficacy, and safety of perampanel given as monotherapy in routine clinical care in people with epilepsy. Poster presented at the 12th European Congress on Epileptology, Prague, Czech Republic, September 11-15, 2016 Funding: Eisai Inc.