Trials demonstrate safety of stem cell therapy for Parkinson’s

Image used for representatin purpose only.
| Photo Credit: Getty Images/iStock Photo

Two independent clinical trials demonstrate the safety of stem cell therapies for Parkinson’s disease. The papers, published in Nature, investigate the use of cells derived from human induced pluripotent stem cells and human embryonic stem cells, respectively.

Parkinson’s disease is a neurodegenerative disease characterised by the progressive loss of neurons that produce dopamine, a neurotransmitter. Cell therapy, specifically replenishing dopamine-producing neurons (dopaminergic) in the brain, could provide a potentially more effective treatment with fewer adverse effects.

To examine the safety and potential side effects of cell therapy for Parkinson’s disease, researchers at Kyoto University, Japan conducted a phase I/II trial. Seven patients received transplantation of dopaminergic progenitors derived from human induced pluripotent stem cells into both sides of the brain. No serious adverse events were reported, and the transplanted cells produced dopamine without overgrowth or forming tumours. The researchers also observed a decrease in motor symptoms associated with Parkinson’s disease (a secondary outcome of the study) in four of the six participants who continued the trial to efficacy evaluation while not taking their standard medication, and in five while taking medication. However, these results varied according to the measures used, with some measures showing minimal changes.

In a separate phase I clinical trial, researchers from Memorial Sloan Kettering Cancer Center, New York, explored the safety of a dopaminergic neuron progenitor cell product (bemdaneprocel) derived from human embryonic stem cells. Twelve patients received surgical transplantation of bemdaneprocel to the putamen on both sides of the brain. Five participants received a low dose and seven received a high dose. There were no severe adverse events related to the therapy during 18 months of follow-up. Some improvement in motor function (a secondary outcome of the study) was observed in patients in both the low-dose and high-dose cohorts. However, the degree of improvement varied across different measured parameters.