Abstracts

Rationale: Combination regimens of antiepileptic drugs (AEDs) with various mechanisms of action (MOA) are commonly used in patients with refractory epilepsy. However, outcomes related to combination AEDs with novel MOA, such as perampanel (PER; a selective non-competitive antagonist of AMPA receptors), are not well described. This study evaluated healthcare resource utilization (HRU) in patients treated with select AED combinations with and without PER in a real-world setting. Methods: A retrospective study was conducted using a large nationally representative claims database from Symphony Health Solutions’ Integrated Dataverse® (08/2012–07/2018). Patients ≥12 years of age treated with AED combinations (identified as an overlap in days of drug supply of ≥90 consecutive days for ≥2 AEDs) who had ≥12 months of baseline and ≥6 months of continuous clinical activity post index date (defined as the date of initiation of the second AED in the combination), and who had ≥1 diagnosis of epilepsy or non-febrile convulsions during the baseline or follow up periods constituted the study population. AEDs were categorized into three MOA categories: sodium channel blockers (SC), synaptic vesicle protein 2A binding (SV2), and selective non-competitive antagonist of AMPA receptors (PER). Patients were classified into three MOA-based cohorts: SC+SC, SC+SV2, and PER+SC. The HRU outcomes included all-cause and epilepsy-related hospitalizations, and outpatient (OP) visits, and were evaluated during follow-up (up to 12 months of post-index treatment). Event rates (calculated as number of events divided by the follow-up duration) were compared between PER+SC and SC+SC or SC+SV2 cohorts using Poisson regression adjusted for baseline covariates including number of AEDs used, status epilepticus, HRU, and number of concomitant AEDs on the index date. Results: The population consisted of 12,152 SC+SC, 46,749 SC+SV2, and 3,790 PER+SC patients (Table 1). During the baseline period, patients in the PER+SC cohort had the greatest prior AED use and highest proportion with status epilepticus, but were younger and had lower Quan-Charlson comorbidity index scores compared to SC+SC and SC+SV2 cohorts. During the follow-up period, the rate of all-cause hospitalization was significantly lower for the PER+SC vs. the SC+SC cohort (adjusted rate ratio [RR]=0.71; p<0.001) and for the PER+SC vs. SC+SV2 cohort (adjusted RR=0.72; p<0.001; Table 2). Similar trends were observed for epilepsy-related hospitalizations. In addition, the rate of all-cause OP visits was also significantly lower in the PER+SC cohort vs. the SC+SC cohort (adjusted RR=0.90; p<0.001) and the SC+SV2 cohort (adjusted RR= 0.92; p<0.001). Conclusions: Results of this study showed that patients treated with PER+SC had significantly fewer all-cause hospitalizations, fewer epilepsy-related hospitalizations, and fewer OP visits compared to patients treated with SC+SC or SC+SV2.  This highlights the benefit of PER compared to other AED combinations in patients with epilepsy. Funding: The study was funded by Eisai Inc.