(C-146) Evaluating Cenobamate among patients with Focal-Onset Seizures: defining a claims-based approach for treatment regimen and outcomes

Background: Focal-Onset Seizures (FOS) are common among patients with epilepsy, and anti-seizure medications (ASMs) are the mainstay treatment. Patients start on monotherapy with add-on ASMs recommended upon lack of response, but polytherapy is associated with increased risk of adverse events and healthcare resource utilization. Examining real-world use of ASM treatment regimens can provide insights into clinically relevant treatment outcomes. Cenobamate (XCOPRI®) is a novel ASM indicated for the treatment of FOS in adult patients, approved in the United States (US) in 2019.

Objectives: To develop a claims-based approach for estimating treatment regimen and subsequent treatment outcomes among adult patients with FOS initiating cenobamate.

Methods: This retrospective observational study used IQVIA PharMetrics Plus database, comprised of claims for approximately 140 million enrollees in the US. We identified adult cenobamate users with FOS, with the date of first dispensation as index date (indexing period: April 1, 2020, to April 30, 2023). Patients had 6 months of continuous enrolment prior to and after the index date. A treatment regimen evaluation (TRE) window of 90 days post-index was defined to evaluate patients on monotherapy (continuous cenobamate use for the duration of TRE) or polytherapy (continuous use of cenobamate and all other ASMs identified +/-30 days of index date for the duration of TRE). All other patients were categorized as undetermined. A treatment outcome assessment (TOA) window of 90 days after the end of the TRE was used to assess if patients continued, augmented, or switched treatment regimens.

Results: A total of 2,809 patients had a dispensing of cenobamate, and 1,132 patients met all eligibility criteria. Among these, 17 patients (1.5%) were on monotherapy and 510 patients (45.1%) on polytherapy. The majority of patients continued the identified treatment regimen through the TOA (66.2%), did not augment treatment (91.5%), and did not switch treatment (97.7%). The 605 patients (53.5%) on an undetermined treatment regimen discontinued cenobamate (n=403/605), the other ASM identified +/- 30 days of index date (n=444/605) and/or had a prescription for an additional ASM (n=592/605) during the TRE.

Conclusions: Claims data are important to identify real-world use of ASMs among patients with FOS. The findings were consistent with previously reported proportions of monotherapy and polytherapy users of ASMs. Defining treatment regimen and subsequent treatment outcomes and evaluation windows can offer insights into clinical practice, drug utilization assessments and evaluation of treatment options for chronic diseases.