Less Than a Third of Patients With Focal Epilepsy Become Seizure-Free on First ASM
Most patients with newly diagnosed focal epilepsy require more than 1 antiseizure medication (ASM) and more than 1 year to achieve seizure freedom, according to results from a multicenter prospective cohort study published in JAMA Neurology.
“A recent review of treatment-resistant epilepsy emphasized that persistence of seizures was not synonymous with treatment resistance,” wrote corresponding author Sarah N. Barnard, MD, MIPH, of Monash University School of Translational Medicine, Melbourne, Australia, and coauthors. “This was confirmed in our study.”
The international Human Epilepsy Project cohort study included 448 patients with newly diagnosed focal epilepsy followed over a median 3.13 years. Researchers aimed to describe the short- and long-term response to ASM treatment, with freedom from seizures serving as the primary outcome.
In line with International League Against Epilepsy definitions, seizure freedom was defined as a 12-month seizure-free period or 3 times a patient’s greatest pretreatment seizure-free interval, whichever was longer. Treatment response was categorized as sensitive (seizure free with 2 or fewer ASM trials), resistant (2 or more ASM trial failures), or indeterminate (neither treatment sensitive nor resistant).
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According to the study, most patients (59.6%) achieved seizure freedom over follow-up. Once achieved, 83.5% did not relapse. Regarding ASM response, 54.7% of patients were treatment-sensitive, 22.8% were treatment-resistant, and 22.5% were indeterminate.
Just 27% of all patients became seizure free while receiving their first ASM. In the first year of treatment, 63% of patients had ongoing or worsening seizures. The median time to first seizure freedom was 12.1 months.
“This suggests that in the first 12 months of receiving a diagnosis of focal epilepsy, patients will have a greater likelihood of experiencing recurrent seizures than not. This should provide guidance for clinicians that the first year is likely one of high seizure risk and maximal disruption to a person’s life,” researchers wrote. “This may also provide some reassurance that ongoing seizures in the first year does not necessarily indicate forthcoming treatment resistance.”
Patients with infrequent pretreatment seizures were less likely to be treatment resistant, the study found, while patients with a history of psychiatric disorders were 1.78-fold more likely to be treatment resistant.
“Our study also showed many patients do not clearly fit into treatment phenotypes, and ongoing seizures does not always equate to treatment resistance,” researchers wrote. “Future research can address these prognostic uncertainties.”
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