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Tyler Priddy at a follow-up visit at UAMS in May.
UAMS Performs Groundbreaking Epilepsy Surgery as Part of FDA-Approved Clinical Trial
| LITTLE ROCK — Surgeons from the University of Arkansas for Medical Sciences (UAMS) have performed the first transplantation in Arkansas of interneuron cell therapy, called NRTX-1001, into a patient with non-lesional epilepsy as part of an FDA-approved clinical trial under way at multiple locations across the United States.
Four months later, the 33-year-old patient, who has had seizures daily since the age of 12, reports a significant reduction in all three types of seizures he has experienced for more than half his life.
Sisira Yadala, M.D., a neurologist who directs the UAMS Division of Epilepsy and the UAMS Level 4 Comprehensive Epilepsy Center, is the principal investigator for the study at UAMS. She said Tyler Priddy of Hot Springs was the 19th patient enrolled in the study and the first with non-lesional epilepsy to undergo the treatment.
Non-lesional epilepsy refers to the absence of any structural abnormalities, as detected on brain scans, and accounts for roughly 20% to 40% of all epilepsy cases.
Viktoras Palys, M.D., a neurosurgeon at UAMS, and Brooke Elberson, M.D., chief neurosurgery resident at UAMS, performed the five-hour surgery Feb. 12 as part of a groundbreaking, FDA-approved clinical trial using human inhibitory interneuron cell therapy.
“This treatment has the potential to change the landscape of epilepsy care,” Yadala said. “The transplanted cells are a specialized lineage of human interneurons with the capacity to migrate through brain tissue, integrate into existing neural circuits and regulate local network activity. Preclinical proof-of-concept studies have shown this cell therapy to be safe and effective in reducing seizure activity.”
“The hope is that these transplanted interneurons help restore inhibitory chemical balance in seizure-prone brain regions, potentially reducing or eliminating seizures in people who have epilepsy,” said Palys, surgical director of the epilepsy center. “Currently, the trial focuses on transplanting these cells into the human hippocampus.”
In Priddy’s surgery, these interneurons were injected “into a normal appearing hippocampus,” he added.
“Results will take several months, as the transplanted cells need time to integrate into the brain network and be recognized as the brain’s own,” Palys said. “Early results of this open label trial have shown promise. The next step is a double-blind, randomized trial that the sponsor company, Neurona, plans to start at the end of 2025.”
Ultimately, Palys said, “this technique could pave the way for cell implantation in various brain regions where seizures originate, offering a minimally invasive, potentially curative treatment for epilepsy. This approach could eliminate the need for anti-seizure medications, brain tissue removal or bulky stimulators that require periodic battery replacements.”
Priddy said that during his 21 years of experiencing epileptic seizures, he has suffered numerous injuries, including knocked out teeth and a broken nose, and has needed five facial reconstruction surgeries. He also has wrecked three cars. He once woke up in an ambulance while on a family vacation in Orange Beach, Alabama, and he blacked out at work, only to discover from security footage that he was walking in circles.
Despite having two master’s degrees, the married father of three said the seizures make it difficult to find and hold a job, especially because he can no longer drive. He said his doctors have tried numerous medications, on their own and in various combinations, to try to control his seizures, but nothing has stopped them completely — even though he is now taking 17 pills a day.
Priddy said the seizures have held him back in some areas of his life, but the results of the surgery give him hope.
“I’m not worried about it,” he said. “I’m confident.”
In the three months since his surgery, Priddy said he has only had one of his “fallout seizures,” which are better known as tonic clonic or grand mal seizures. Before the surgery, he had a tonic clonic seizure every two or three weeks. These seizures are characterized by muscle stiffening, loss of consciousness and uncontrollable jerking movements.
Priddy also has a history of focal seizures, which he said cause him to “black out” or drift away, usually for a few minutes. They involve just one area of the brain but can move into other areas and lead to full-blown tonic clonic seizures. He said his focal seizures have decreased from at least twice a week to once every two weeks.
Meanwhile, his “aura” seizures, during which he retains consciousness but experiences fleeting sensory or visual changes, have decreased to about one every other day. Those seizures used to happen twice a day.
The Phase I/II study is being conducted for Neurona Therapeutics, a clinical-stage biotherapeutics company. It is evaluating NRTX-1001, an investigational nerve cell therapy, in patients with drug-resistant mesial temporal lobe epilepsy.
“The treatment may help with focal seizures with or without altered consciousness as well as secondary generalized tonic clonic seizures,” Yadala said. “If the current trial results are promising, future studies may expand to include other forms of focal epilepsy with seizure origins outside the temporal lobe. However, this therapy is not currently available for individuals with primary generalized epilepsy.”
According to Neurona, NRTX-1001 is made from human stem cells that have been developed into interneurons, like the cells already in the brain. They produce GABA, a neurotransmitter in the brain that is thought to inhibit seizure activity. It is hoped that through implantation of NRTX-1001, the interneurons will form connections in the brain, and the release of GABA will quiet the nearby neurons and help limit the abnormally ‘excited’ signals, resulting in fewer seizures.
The study has been underway for more than two years. Study participants are between 18 and 75 years old whose seizures haven’t responded to at least two seizure medications and whose seizure frequency is at least four every 28-day cycle during the previous six months.