Abstracts

Rationale: For patients with epilepsy who are unable to tolerate or achieve seizure control with their first-line (1L) antiepileptic drug (AED) therapy, initiation of a second-line (2L) AED regimen can be an important step towards achieving seizure control and optimal outcomes. The objective of this study was to assess the clinical and economic impact of immediate vs. delayed initiation of 2L AED therapy following failure of a 1L AED monotherapy. Methods: Administrative claims (IMS PharMetrics Plus) were used to identify adult patients who initiated oral AED monotherapy (1/1/2007 - 9/30/2011). The first observed AED fill was defined as the index event. Patients were required to have ≥180 days pre- (with no AED use) and ≥360 days post-index continuous enrollment (CE) in a health plan and ≥2 epilepsy/convulsion diagnoses (ICD-9-CM: 345-345.5;345.7-345.9/780.3/780.39). Treatment failure, defined as an ER/inpatient visit with a primary diagnosis of epilepsy/convulsion or AED-related adverse event, was assessed post-index while persistent on the index therapy. For patients who experienced failure, time to 2L initiation of a non-index oral AED in the 180-days post-failure was assessed; patients were categorized based on time to 2L initiation: Immediate (0-14 days after failure), and Delayed (15-180 days after failure), and matched using propensity scores. All-cause and epilepsy-related healthcare resource utilization and costs (2013 USD) in the 180-days post-failure were compared (statistical tests were conducted on the median for continuous variables). Results: Of 25,204 epilepsy patients initiating AED monotherapy (mean age 45.7±17.6 years, 51.7% female), few (11.3%) had evidence of 1L treatment failure in the first year, of whom, 21.7% initiated a 2L therapy within 180 days (9.0% Immediate, 12.7% Delayed). Propensity score matching resulted in 231 matched pairs. All-cause ER costs and total epilepsy-related medical costs were higher among the Delayed cohort ($428 v. $206; p=0.02 and $2,845 v. $1,911; p=0.02, respectively). Total pharmacy costs were similar between cohorts (Immediate: $2,011, Delayed: $1,965; p=0.6). Oral AED pharmacy costs were significantly higher among the Immediate cohort ($1,058 v. $787; p=0.02). Total epilepsy-related medical costs were higher among the Delayed cohort ($2,845 vs. $1,911; p=0.02). Conclusions: In this study, one in 10 patients with epilepsy had evidence of first-line treatment failure resulting in an ER or inpatient stay, and of these, about one in five initiated a second-line therapy in the 6-month period following first-line failure. Immediate initiation of 2L therapy following 1L AED failure was associated with significant epilepsy-related medical cost savings (a median of $944 per patient in the first six months) compared to delayed initiation. The higher oral AED pharmacy costs (median $271 in the first six months) observed in the Immediate cohort likely reflect a more aggressive disease management strategy among these patients.