AUTHOR=Hersi Hire , Saarinen Jukka T. , Raitanen Jani , Peltola Jukka 

TITLE=Response to subsequent antiseizure medications after first antiseizure medication failure in newly diagnosed epilepsy

JOURNAL=Frontiers in Neurology

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2022.1042168

DOI=10.3389/fneur.2022.1042168

ISSN=1664-2295

ABSTRACT=Abstract
Objective: There is lack of studies using the International League Against Epilepsy (ILAE) recommendation to define drug-resistant epilepsy (DRE). This study evaluated the seizure freedom rates of substitution or add-on and subsequent antiseizure medication (ASM) therapies using different proposed definitions of DRE or ASM trials in patients with a failed first ASM. We also identified prognostic factors for 1-year seizure freedom.
Methods: This study included 459 epilepsy patients of whom 151 were not seizure-free after the first ASM. Multilevel mixed-effects logistic regression was used to examine the correlation between observations from the same patient.
Results: The overall seizure freedom rate with the first and subsequent ASMs was 88.0% (404/459). The rate of DRE when defined as the failure of two ASMs for any reason was 20.0%, and according to the ILAE definition of DRE, it was 16.3%. After failing the first ASM, 63.6% of patients (96/151) became seizure free with subsequent ASMs and tried an average of 1.9 ASMs (range 1-5). Of the patients who achieved 1-year seizure freedom, 10.1% (41/404) were taking polytherapy and there was no difference between substitution and add-on. All the patients with generalized epilepsy were seizure-free. A favorable prognostic factor was age > 60 years and an EEG without epileptiform activity. The efficacies of the different ASMs were largely similar, but drugs that enhanced GABA-mediated inhibitory neurotransmission had the lowest seizure freedom rate.
Significance: In adults with newly-diagnosed epilepsy one-year seizure freedom was achieved for almost 90% of the patients, after failing the first ASM two-thirds responded to subsequent ASM regimens.  Our results support the feasibility and applicability of the ILAE concept of an adequate ASM trial and the failure of two ASMs as a definition of DRE.