Cloned stem cells can replace dead dopamine cells, offering hope for Parkinson's cure
A Korean clinical study is drawing attention, showing that new dopamine cells made by cloning embryonic stem cells can replace dead dopamine cells in the brain to treat Parkinson's disease.
The study results of the embryonic stem cell-derived Parkinson's disease treatment, which came 20 years after the “Hwang Woo-suk scandal,” show excellent safety and efficacy in a one-year clinical study, with experts saying that the incurable disease will likely be conquered soon.
A team, led by Professor Jang Jin-woo of the Department of Neurosurgery at Korea University Anam Hospital and Professor Lee Phil-hyu of the Department of Neurology at Severance Hospital, said that, for the first time in Asia, human embryonic stem cell-derived midbrain dopamine neurons were transplanted into the brains of three patients, who were diagnosed with Parkinson's disease more than five years ago and followed up for one year, confirming their safety and efficacy.
The patients in the study had experienced side effects, including wearing off and freezing of gait despite anti-Parkinson's medications, and the study won approval for phase 1/2a clinical trials from the Ministry of Food and Drug Safety.
Currently, the three patients who received the initial low dose (3.15 million cells) that are already one year old have not shown any side effects related to the cell transplant or surgery on MRI or CT.
Regarding efficacy, a mean reduction of 12.7 points on the MDS-UPDRS Part III (off) assessment, the most objective motor function measure, was also seen, indicating a return to good motor function. There was also improvement in weakness and behavioral deficits.
One year after transplantation, dopamine brain imaging (FP-CIT-PET) showed increased dopamine transporter, suggesting partial dopamine neuronal engraftment, which correlated with improvement in Parkinson's symptoms.
In the ongoing clinical trial of embryonic stem cell-derived Parkinson's disease in the United States, the MDS-UPDRS Part III (off) assessment at one year showed a mean recovery of 7.6 points in the low-dose (1.8 million cells) group and 12.4 points in the high-dose (5.4 million cells) group.
"Although the clinical evaluation is of the first three low-dose patients one year after surgery, not all 12 patients, we did not find any unusual problems with transplantation and cell-related safety, and all three patients showed excellent results in clinical efficacy," Professor Jang said.
Professor Kim Dong-wook of the Department of Physiology at Yonsei University College of Medicine, who developed the embryonic stem cell-derived cell therapy, said, "The investigational cell therapy is world-class, with better dopamine cell purity and transplanted dopamine cell survival than the U.S. embryonic stem cell clinical team. The results of the animal study and the clinical trial appear quite consistent."
This suggests that it has the potential to be a fundamental treatment that goes beyond symptomatic treatment and replaces dead dopamine cells with new ones in the patient's brain, Professor Kim added.
The researchers plan to enter the next phase of the phase 2b/3 clinical trial in more patients once they confirm the long-term safety and clinical efficacy of the full 12 patients who received the transplant.