Most patients with focal epilepsy still have seizures during first year of treatment
Key takeaways:
- Among those deemed “treatment sensitive,” 69.4% eventually achieved seizure freedom.
- More than half of participants reached at least one period of seizure freedom during a 6-year follow up.
LOS ANGELES — For those newly diagnosed with focal epilepsy and given antiseizure medications, most will be sensitive to treatment, with seizure freedom likely to occur after the first year of administration, according to a presenter.
“What we were hoping to address was the paucity of data on focal epilepsy alone,” Sarah N. Barnard, MD, MIPH, research fellow in the department of translational medicine at Monash University in Australia, told attendees at the American Epilepsy Society annual meeting. “We also wanted to address some variability in the literature around how we define seizure freedom and how we define treatment.”
Barnard and colleagues sought to address these issues by looking at the Human Epilepsy Project, a 6-year international prospective cohort study conducted at 34 tertiary epilepsy centers, predominantly in North America and Europe.
The study courted individuals aged 12 to 60 years with a confirmed diagnosis of focal epilepsy. Patients were enrolled within 4 months of treatment initiation with antiseizure medications (ASMs) and were followed for up to 6 years from time of diagnosis.
A total of 448 individuals (60% women; median age at seizure onset, 29 years; median age at treatment initiation, 32 years) were included for analysis. A patient was considered seizure-free when they either recorded no seizures for 12 months, or for three times longer than the longest pre-treatment seizure-free interval, whichever was longer.
Additionally, success was defined as a seizure-free period when prescribed ASMs, and failure was defined as evidence of at least one seizure on a therapeutic ASM dose with no seizure-free period achieved. Treatment resistance was defined as a failure of the first two trial periods on ASMs, and treatment sensitivity as a patient reaching a period of seizure freedom following two or more ASM trials. There was also an “indeterminate” category, defined as having ongoing seizures on fewer than two ASM trials, or insufficient follow ups where seizure freedom could not be properly assessed.
Treatment outcomes were determined by reviews of patient ASMs and cross-referenced with patient-reported seizure incidence through an online diary as well as patient medical records.
According to the results, 245 individuals (55%) were deemed treatment sensitive, 102 as treatment resistant (23%) and 101 (22%) were indeterminate.
Among the treatment-sensitive group, 170 patients (69.4%) eventually achieved seizure freedom, 40 (16.3%) had a breakthrough seizure and 35 (14.3%) suffered relapsing or remitting of seizure activity.
Barnard and colleagues found that 267 participants reached at least one period of seizure freedom and 168 others did not achieve seizure freedom during the follow-up interval.
Data further showed that at 12 months from treatment initiation, 37% of participants did not experience more seizures, with the median time from treatment initiation to commencement of an initial seizure-free period being 12.1 months; another 36% logged fewer seizures; and 27% either maintained or experienced worsening seizure frequency.
“The big takeaway is that in the first year of treatment remains high risk, even for our treatment-sensitive patients,” Barnard said. “For most, seizure freedom can take over a year or longer to achieve.”
Collapse
Barnard SN, et al. Treatment response to anti-seizure medications in newly diagnosed focal epilepsy: Findings from the Human Epilepsy Project. Presented at: American Epilepsy Society annual meeting; Dec. 6-10, 2024; Los Angeles.
