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A new drug reduced seizures in subjects with treatment resistant epilepsy in a recent clinical trial. The Good Brigade/Getty Images
  • Researchers say a new medication may potentially reduce seizures by more than 50% in people with epilepsy.
  • They reported the drug also eliminated seizures in some study participants.
  • The medication targets focal seizures, which affect a single brain area and occur when nerve cells send out sudden, excessive burst of electrical signals.

People with epilepsy who added a new medication, XEN1101, to their treatment routine had seizures reduced by a third to more than 50%.

According to a study published on October 9 in JAMA Neurology, some people treated with the drug remained seizure-free during the 8-week treatment period.

The study, a phase 2B clinical trial, ran from January 2019 until September 2021. It included 325 men and women with epilepsy.

Participants had already tried and stopped an average of 6 drugs that failed to treat their focal seizures. They also had experienced at least four episodes a month despite ongoing treatment.

The participants randomly received either a daily oral capsule of XEN1101 or an inert placebo tablet that looked identical to the actual drug.

The medication targets focal seizures. These are the most common type of seizures and occur when nerve cells in a particular brain region send out sudden, excessive bursts of electrical signals.

Focal seizures, also called partial seizures, affect a single brain area, most commonly the temporal lobe. The difference between a seizure and epilepsy depends on the number of episodes, according to the National Institutes of Health.

A seizure is a single episode with a low risk of recurrence. Epilepsy is when two or more unprovoked seizures occur more than 24 hours apart.

Therapies currently available do not stop seizures in about one-third of people.

“We always need new seizure medications as many patients with intractable epilepsies often require treatment with more than one seizure medication,” Dr. Clifford Segil, a neurologist at Providence Saint John’s Health Center in California who was not involved in the study, told Medical News Today.

“This study with a novel potassium channel opener seems reasonable.”

The participants who added XEN1101 to their current medications saw seizures drop by between 33% and 53%. Those taking a placebo saw a drop of 18%.

The treatment phase of the trial lasted eight weeks. However, most participants volunteered to extend their trial. About 18% remained seizure-free after six months and 11% for a year or longer.

“The data is premature, and only 325 patients were enrolled in this study. I am always more concerned with tolerability than efficacy because if a medication makes someone feel awful, they will not take it.” Dr. Segil said.

“In this study, there was a 3.5% discontinuation rate due to dizziness, slurred speech (dysarthria), and inability to walk (gait disturbances).”

Dr. Segil noted some subjects experienced adverse effects of the new epilepsy drug. These included:

“Prior to using this medication, I would like to see more cardiac evaluations to make sure this novel potassium channel opener did not cause any cardiac arrhythmia and a comparison study to a currently used focal onset seizure approved medication or a head-to-head trial to determine if it’s better than what we have. “If it is not better than what we are using, there is no point in using it clinically.”
— Dr. Clifford Segil, neurologist

Xenon Pharmaceuticals, a biotechnology company based in Vancouver, Canada, that develops therapies for neurological disorders, including epilepsy and major depressive disorder (MDD), funded the study.

Xenon Pharmaceuticals is the maker of XEN1101.

“Once a drug is in clinical trials, it is almost certain that the study will be done by the sponsor (the pharmaceutical company), who is developing the drug for ultimate [Food and Drug Administration] approval,” Dr. Jacqueline French, a professor at NYU Comprehensive Epilepsy Center in New York and lead author of the study, told MNT.

“This was true for other recent breakthrough therapies, such as the new therapies for spinal muscular atrophy, Alzheimer’s disease, and multiple sclerosis. Therefore, it is not surprising to medical professionals. It is very important for the academic community to work with the sponsors to ensure that the study is done with the highest rigor and the most interpretable results.”
— Dr. Jacqueline French, lead study author

Of course, studies run by pharmaceutical companies can sometimes be problematic.

“I think there are partnerships between academia and industry, and the fact that this was not completely run by a pharmaceutical company and the patients were part of NYU’s Comprehensive Epilepsy Center adds legitimacy to the results,” Dr. Segil noted.

“Studies completely run by pharmaceutical companies are more challenging for me to believe than studies like this one, which are performed at academic centers with funding from pharmaceutical companies.”

The next step, already underway, is to perform another randomized, placebo-controlled trial to confirm the results.

Epilepsy is the most common condition affecting the brain.

Approximately 5 million people in the United States have a history of epilepsy, with more than 3 million having active epilepsy, according to the Centers for Disease Control and Prevention (CDC).

Seizures are the main sign of epilepsy.

Seizures typically last anywhere from a few seconds to a few minutes. They can appear differently.

For example, one person might stare and another might shake or fall. The person having the seizure can lose awareness of what is going on around them or seem confused and dazed.

There are two major types of seizures:

  • Generalized seizures affect both sides of the brain.
  • Focal seizures affect just one area of the brain. They are also called partial seizures.

A person can also have more than one type of seizure.

For many people, the cause of epilepsy is unknown. Some causes of seizures can be linked to: