(72) Treatment patterns among patients with newly diagnosed epilepsy in the United States

Background: : While prior studies have evaluated treatment patterns among patients with epilepsy in the United States, many predate recent therapeutic advancements and do not categorize antiseizure medications (ASMs) by mechanism of action (MOA).

Objective: : To describe treatment patterns among newly diagnosed patients with epilepsy, including treatment duration, sequencing, and transitions based on MOA.

Methods: : This retrospective study used 100% Medicare Fee-for-Service claims and the Inovalon MORE2 closed claims database (01/01/2016–12/31/2023) to identify patients with incident epilepsy (01/01/2017–12/31/2019), defined by ≥2 outpatient or ≥1 inpatient claims with specific ICD-10 codes (G40.0X, G40.1X, G40.2X, G40.5X, G40.80X, G40.89, G40.9X). The index date was defined as the initiation of the first line of therapy (LOT1) lasting ≥30 days. LOTs were constructed using daily drug arrays, with agents started within 30 days of index considered part of LOT1. LOTs ended at discontinuation (≥60-day gap in all treatment), switch (new agent with < 30 days overlap), augmentation (new agent with ≥30 days overlap), or partial drop (discontinuation of one or more agents for ≥60 days). Up to four LOTs were captured per patient. ASMs were grouped by MOA: GABA, sodium channel blockers, calcium channel blockers, SV2A, AMPA, and other/mixed.

Results: : A total of 90,738 patients met inclusion criteria (median age 58 years; 55% female; 61% Caucasian). Among those initiating treatment, 87% of patients began with a single MOA regimen, with 41% of patients specifically initiating therapy with an SV2A. Sankey analysis revealed that 34% of patients remained on the same MOA from LOT1 to LOT2. A notable portion who changed therapies eventually returned to their index MOA; by LOT3, 27% of those who had changed therapies in LOT2 had reverted to their index MOA. The median duration of treatment was 5.4 months in LOT1, 3.8 months in both LOTs 2 and 3, and 3.3 months in LOT4. The median time from the start of LOT1 to the initiation of LOT2 was 10.0 months, decreasing to 6.4 months between LOTs 2 and 3, and 5.8 months between LOTs 3 and 4.

Conclusions: : Patients with newly diagnosed epilepsy appear to cycle through ASMs with previously tried MOAs, with a notable portion eventually returning back to their index MOA. Time to next treatment shortens with each line of therapy, indicating faster treatment changes in later lines. This pattern underscores not only the limited long-term effectiveness of existing ASMs but also the lack of novel MOAs in the current therapeutic landscape.

Sponsorship:: Xenon Pharmaceuticals Inc.