Interneuron cell therapy results in up to 94% seizure reduction in focal epilepsy

Key takeaways:

• Human GABAergic interneurons were implanted in two patients with drug-refractory focal epilepsy.
• Preliminary results show participants have experienced greater than 90% seizure reduction since surgery.

BOSTON — Implantation of GABAergic interneuron cells in two patients with drug-resistant focal epilepsy resulted in significant seizure reduction, according to preliminary data presented at the American Academy of Neurology annual meeting.

“Unfortunately, not all patients are candidates for epilepsy surgery, and for those who are, surgery carries some risk,” David C. Spencer, MD, director of the Comprehensive Epilepsy Center and professor of neurology at Oregon Health & Science University, said during an AAN-sponsored press conference prior to the meeting. “Our work is studying the possibility of boosting inhibition in the seizure focus, using implanted human inhibitory neurons.”

Spencer and colleagues sought to examine whether implantation of human GABAergic interneurons could control seizures in individuals with drug-resistant mesial temporal lobe epilepsy.

They conducted a first-in-human phase 1/2 clinical trial and enrolled two individuals with unilateral mesial temporal lobe epilepsy with hippocampal sclerosis and refractory focal seizures. The pair underwent EEG, MRI and memory, mood and visual field assessments, and received immunosuppressive therapy one week prior to implantation, which tapered after 1 year.

Researchers implanted the cells at the back of the skull along the long axis of the hippocampus using MRI guidance. Implantation occurred without complication and on target in both participants, who recovered overnight and were allowed to return home the next day.

According to preliminary results, the first participant — who was dosed 6 months ago — has had a 93% seizure reduction from a baseline (32 seizures/month) at 8 months follow-up, and has not had a focal awareness-impaired seizure since the first month. The second participant is 2 months out from dosing and has experienced a 94% reduction in seizure frequency, from 14 per month at baseline to one since surgery. No serious adverse effects have been reported.

“We are very excited by this approach, which is restorative instead of destructive,” Spencer said. “And while these are still early days, we are encouraged by the positive safety findings so far and intrigued by some of these early seizure responses.”