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• Posted October 22, 2025

New Study Offers Hope for People With Drug-Resistant Epilepsy

For the estimated one-third of people with focal epilepsy who don’t respond well to initial medications, new research offers significant reason for optimism. 

A study suggests that even those considered "treatment-resistant" may eventually see a substantial reduction in their seizures over time.

Focal epilepsy, the most common form of the neurological disorder, occurs when nerve cells in one area of the brain fire off an excessive burst of electrical signals. 

These focal seizures can manifest as unusual behaviors, abnormal emotions or strange sensations.

The new study, part of the international Human Epilepsy Project, tracked nearly 150 adults who were deemed treatment-resistant. In other words, they still had seizures despite having tried at least four different anti-seizure medications. Some participants also had implantable devices. 

The researchers monitored participants for up to three years.

The results, published Oct. 20 in JAMA Neurology, showed a promising outcome: 68% of participants had a reduction in seizure frequency during the second half of the study compared to the first half.

This finding directly contradicts the long-held assumption that the prospect for relief is remote when patients fail a handful of medications.

“Our findings challenge the assumption that once a patient with focal epilepsy has failed a certain number of anti-seizure drugs, their chances of finding relief are small and not worth the effort,” said lead author Dr. Ojas Potnis, a neurology resident at the NYU Grossman School of Medicine in New York City.

While medications rarely halted seizures completely, they did appear to lengthen the intervals between episodes for some patients, the study found.

• Almost 13% of volunteers went at least three months without a seizure.

• Nearly 8% were seizure-free for at least six months.

• And 3% of patients achieved a full year or more without a seizure.

Potnis noted that these percentages, while appearing small, are higher than those found in earlier studies, which followed patients for just three months. This suggests that achieving seizure reduction is often a long game.

The data also indicated that the total number of medications a patient had failed previously had no bearing on their future likelihood of improvement.

The study noted that the four most common anti-seizure medications used by participants who experienced seizure reduction were all approved within the past 15 years. They are cenobamate, clobazam, eslicarbazepine and epidiolex.

The researchers also found that whether or not patients had an implantable device had no effect on seizure trajectory.

“These results offer hope that focal epilepsy will get better over time for most people,” said co-senior author Dr. Jacqueline French, a neurologist and professor at the NYU Grossman School of Medicine.

“Health care providers should keep searching for the best treatment regimen for their patients no matter how many therapies they may need to try,” she added in a news release.

The researchers said it remains unclear whether this gradual reduction in seizures is a result of therapeutic management — as more than half of those who improved started a new drug during the study — or the natural progression of disease over time.

The study was funded by UCB, Neurelis and SK Life Science.

More information

The National Institute of Neurological Disorders and Stroke provides information on epilepsy .

SOURCES: NYU Langone Health, news release, Oct. 20, 2025; JAMA Neurology, Oct. 20, 2025