Stem cell therapy TED-A9 showing safety and early efficacy in trial
Treatment at low and, especially, high dose easing symptom severity
The first six Parkinson’s disease patients given the investigational stem cell-based therapy TED-A9 in a clinical trial showed safety and an easing in their symptoms over one year of follow-up, the company developing the treatment, S.Biomedics, reported.
A total of 12 adults, all diagnosed with Parkinson’s five or more years ago, have been treated with a single transplant of stem cells in the ongoing Phase 1/2 clinical study (NCT05887466), taking place in South Korea. Among the six patients evaluated for a year after the treatment, intending to replace dopamine-producing nerve cells in the brain, three were treated at low dose and three at high dose.
“We are excited by our data package, which shows a positive trend throughout the study period,” Dong-Wook Kim, MD, PhD, chief technology officer of S.Biomedics, said in a company press release. “We will continue to unveil new data through our ongoing study.”
Stem cell therapy for Parkinson’s aiming to restore dopamine-producing neurons
Parkinson’s results when the nerve cells that produce dopamine in the midbrain’s substantia nigra, called dopaminergic neurons, begin to gradually die. Dopamine, a chemical messenger, is involved in motor control, and when there’s less of it, characteristic disease motor symptoms start to become evident.
TED-A9 is a cell therapy that contains precursors to dopaminergic neurons derived in the lab from human embryonic stem cells, a type of cell that can develop into almost any other type of cell. These precursor cells are surgically transplanted into the substantia nigra, where they can mature into dopaminergic neurons and potentially ease patients’ symptoms.
In the single-site trial, six adults received TED-A9 at a low dose of 3.15 million stem cells at Yonsei University’s Severance Hospital in Seoul, and another six were treated at a dose containing twice as many stem cells, 6.3 million. A final treatment was administered in February.
The study’s goal is to determine treatment safety and to explore signs of its efficacy over the two years following TED-A9 administration. The trial is expected to conclude in early 2026.
Over the course of one year of follow-up, the first three treated patients in the low-dose and high-dose groups showed a lessening in their motor symptoms. The severity of functional disability was assessed using the Hoehn and Yahr scale, with higher stages indicating more severe motor symptoms. Among the three low-dose patients, the stage decreased from 3.7 to 3 (an average improvement of 19.4%), while among those in the high-dose group, it dropped from 3.7 to 2 (an average improvement of 44.4%).
Changes in disability seen in these high-dose patients indicate “a notable shift from severe to milder disease states,” the company reported.
12 adults in the study all had at least 2 hours of daily off times
All enrolled patients, ages 50 to 85, were on a stable dose of levodopa for at least three months. Still, they experienced off periods for at least two hours a day, times when motor symptoms return or with freezing of gait, episodes in which patients feel unable to move. TED-A9 was reported to ease freezing of gait in one of two patients in the low-dose group, and for all three in the high-dose group.
Assessments using the Movement Disorders Society-Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) part III, where higher scores indicate more severe motor symptoms, also indicated benefit. Low-dose therapy patients had a 12.7-point decrease on this scale during off periods, amounting to a 22.7% improvement, while a similar 13-point decrease was recorded for the high-dose group, equivalent to a 25.3% improvement.
Neuroimaging studies using positron emission tomography revealed an increase in the number of dopamine transporters, the proteins that take dopamine into neurons. This indicated a successful engraftment of the stem cells, meaning they had matured and replaced lost dopaminergic neurons. A greater increase in transporter numbers was evident in high-dose patients relative to those given the low dose.
Safety was being seen in treated patients, with no adverse events related to the transplanted cells reported. One of the 12 patients had a mild brain hemorrhage in an area unrelated to the transplant site.
“The results demonstrate that we have developed a cell therapy that not only promotes behavioral recovery but also confirms the mechanism through neuroimaging,” said Kim, who is also a professor at Yonsei University College of Medicine.
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