Drug-switched brain therapy tried in 3 people with hard-to-treat epilepsy

A technique that neuroscientists have used for years in lab animals has now been tried in people. In a small pilot study, researchers used engineered “designer” receptors to change how part of the brain behaves in three people with epilepsy that medicines did not control.¹ The therapy appeared safe, and it may have reduced seizures as long as the patients kept taking a companion drug.¹ The study was not built to test whether the therapy works, so these are early hints only.¹

What happened

The results were reported in the New England Journal of Medicine in 2026 and described by Chemical & Engineering News on November 4.¹ According to that report, the three-patient study is the first time researchers have used designer receptors, commonly called DREADDs, to change the activity of an adult’s brain.¹

The approach is known as chemogenetics. It has a two-part design. First, cells in a chosen part of the brain are given instructions to make a receptor that does not normally exist there. A receptor is a kind of molecular switch on a cell. Second, the patient takes a drug that fits that switch. In principle, the drug only acts on the cells carrying the designer receptor, so it can change activity in one targeted circuit rather than across the whole brain.

Neuroscientists quoted in the coverage called the study’s hints at safety and benefit exciting, while noting it was a pilot study rather than a formal clinical trial.¹ Researchers are particularly interested in the prospect of changing the activity of specific circuits in an adult’s brain.¹

How the receptors got into the brain

The research team delivered a virus carrying the chemogenetic receptors to a specific part of each person’s brain, using a surgical approach similar to operations guided by magnetic resonance imaging (MRI) scans.¹ Viruses used this way are stripped-down delivery vehicles: they carry genetic instructions into cells. Other gene therapies for the brain have used the same general idea, such as a mouse study at University College London that packaged its gene in a harmless viral vector.²

Once the cells make the receptor, the companion drug acts as the on-switch. The coverage reports that any seizure reduction appeared to last only while patients stayed on that drug.¹ That fits the basic design: the receptor by itself is meant to do little until the drug is present.

The evidence so far

Here is what the available reporting says was found:

• Who: three people with epilepsy that was not controlled by medication.¹
• Safety: the chemogenetic therapy appeared safe in these patients.¹
• Seizures: the therapy may have reduced seizures as long as the patients stayed on the companion drug.¹
• Design: a pilot study, not a formal clinical trial, and not designed to measure efficacy (whether the treatment actually works).¹

The published report’s own seizure counts, follow-up length and the name of the companion drug were not included in the material available to Biohack, so this article does not give them.

Epilepsy that resists medicine is a real gap in care. An Irish research group noted in 2012 that medication controls seizures for about two out of three people with epilepsy, while about one in three keeps having seizures despite treatment.³ A seizure is a burst of uncontrolled electrical activity between brain cells.²

What it does not show yet

Three patients is a very small number. With so few people, a study cannot tell whether a drop in seizures came from the therapy, from natural ups and downs in the illness, or from other changes in care. There was no comparison group described in the coverage, and the study was not set up to answer the efficacy question.¹

Safety in three people is also limited. Rare side effects, and effects that appear only after years, cannot be ruled out by a study this size. The therapy involves brain surgery and a permanent genetic change to brain cells, so long-term follow-up will matter.

Finally, the apparent benefit depended on staying on the companion drug.¹ That means this is not a one-time fix. Questions about how the drug is tolerated over long periods, and what happens if it is stopped, remain open.

Who is behind it

The study is one of at least seven trials testing DREADDs in humans in China.¹ News of these trials stunned researchers at a meeting of the US National Institutes of Health’s BRAIN Initiative in August, according to Chemical & Engineering News.¹ The BRAIN Initiative (Brain Research through Advancing Innovative Neurotechnologies) is a US government program funding brain research tools.¹

The available sources do not name the hospital, the lead researchers, the funders or any company involved, and they do not describe conflicts of interest. Biohack will add those details when they can be confirmed from the published report or other sources.

How it fits the field

Researchers have long looked for ways to calm only the brain cells that drive seizures, rather than dampening the whole brain the way many epilepsy medicines do. Earlier efforts have mostly stayed in the lab.

In 2022, a team at University College London reported a different kind of gene therapy in a mouse study of epilepsy. Their therapy was designed to switch on only in overactive brain cells and switch itself off when activity returned to normal.² In seizure-prone mice, it cut spontaneous seizures by about 80% while leaving the animals’ behavior and thinking unaffected, the researchers reported.² They also saw similar effects in “miniature brains” grown from human stem cells in a lab dish.² Those were animal and lab-dish results, not results in people.

The UCL researchers wrote that a limitation of gene therapies for the brain is that they do not tell apart neurons involved in disease from healthy neurons mixed in around them.² Chemogenetics tackles that problem in a different way: instead of the therapy sensing overactivity on its own, doctors choose where to put the receptors and use a drug to control them.

Back in 2012, researchers at the Royal College of Surgeons in Ireland reported a separate approach that targeted a small molecule called microRNA-134, which they found at much higher levels in the seizure-causing part of the brain in people with epilepsy.³ They reported that a drug-like molecule blocking it could prevent seizures in their experiments.³

The new pilot study stands out because it moves a widely used lab tool into human patients. One of the UCL co-leaders, Dimitri Kullmann, said of his team’s approach:

“This approach can be used to treat important neuropsychiatric diseases that do not always respond to medication.”²

Researchers see similar hopes for circuit-targeted therapies in general, though each approach has to prove itself in people separately.

What to watch next

• Fuller data: detailed seizure counts and how long the effects lasted in the three patients.
• The other trials: results from the at least seven DREADD trials reported to be under way in China.¹
• Larger, controlled studies: trials with more patients and a comparison group, which would be needed to show whether the therapy reliably reduces seizures.
• Long-term safety: how patients do over years with the receptors in place and on the companion drug.

For now, the finding is that a technique long confined to lab animals has been used in three people, appeared safe, and may have helped. Whether it becomes a treatment depends on studies that have not yet been reported.