Treatment Response to Antiseizure Medications Can Take More Than One Year

WEDNESDAY, Aug. 27, 2025 (HealthDay News) — Many people with newly diagnosed focal episodes take more than one year and more than one antiseizure medication (ASM) to become seizure-free, according to a study published online Aug. 25 in JAMA Neurology.

Sarah N. Barnard, M.D., M.I.P.H., from Monash University in Melbourne, Australia, and colleagues conducted an international, prospective, observational cohort study at 34 tertiary epilepsy centers, which followed 448 people with newly diagnosed focal epilepsy for up to six years to describe response to treatment with ASMs.

The researchers found that 59.6 percent of participants achieved seizure freedom, largely without relapse (83.5 percent). There were 245, 102, and 101 treatment-sensitive, treatment-resistant, and indeterminant participants (54.7, 22.8, and 22.5 percent, respectively). Of the treatment-sensitive participants, 89.3 percent responded to monotherapy and 49.4 percent became seizure-free while receiving their first ASM (27 percent of the total cohort). Overall, 251 (63 percent) participants had ongoing or worsening seizures in the first year of treatment. The median time to first seizure freedom was 12.1 months, and this occurred earlier in those who never relapsed versus those who relapsed (median, 2.2 versus 7.4 months). Compared with those with very frequent seizures, those with infrequent pretreatment seizures were 0.41-fold more likely to be treatment-resistant (relative risk, 0.41).

“Our findings suggest that those with focal epilepsy should expect a long adjustment period as their health care provider determines the best treatment regimen for them,” senior author Jacqueline French, M.D., from the New York University Grossman School of Medicine in New York City, said in a statement.

Several authors disclosed ties to the pharmaceutical industry.

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