Defining seizure freedom in epilepsy: a pragmatic literature review

Epilepsy is a prevalent brain condition, affecting 50 million people worldwide. Achieving seizure freedom (SF) without intolerable adverse events should be the primary treatment goal. However, the lack of standardized definitions within clinical trials and regulatory and health technology assessment (HTA) evaluations, and uncertainty regarding how short‑term seizure freedom outcomes are interpreted within these contexts present significant challenges in framing consensus. This pragmatic literature review (PLR) aims to characterize how seizure freedom is defined and operationalized in clinical trials, regulatory evaluations, and HTA contexts, to inform the development of a Delphi panel questionnaire.

A pearl growing approach was applied. Searches were conducted across PubMed, Cochrane, ClinicalTrials.org (2019 - 2024), regulatory and Health Technology Assessment (HTA) reports, using terms related to epilepsy, anti-seizure medication (ASM), and SF. Articles reporting SF as an outcome in pharmacological epilepsy treatments were included. Data were screened, extracted, and narratively summarized.

From 147 references, 25 articles were included for review following deduplication. Definitions of SF varied based on population (adult, pediatric, geriatric), seizure type (focal, generalized), clinical setting (trials, real-world studies), and data analysis method (intention to treat vs. per protocol). Variable requirements for defining SF in regulatory and HTA were also identified.

No consensus exists regarding how seizure freedom is operationalized and reported within clinical trials and regulatory and HTA evaluations. This pragmatic literature review highlights substantial variability in definitions and measurement approaches across these contexts. The findings will be used to inform a Delphi panel exercise aimed at building expert consensus on how seizure freedom should be defined and applied in clinical trials, regulatory, and HTA settings.