Landmark European stem cell trial announces positive results
The STEM-PD trial team have shared that 6 out of 7 people who received the stem cell therapy have been able to reduce their Parkinson’s medication.
The STEM-PD trial, led by Lund University in Sweden and the University of Cambridge in the UK has announced the positive first results of their stem cell study, a year after the trial surgery took place.
What is the STEM-PD trial?
Stem cells might offer a way to replace some of those cells that are lost. We’ve invested millions in stem cell research to drive forward their potential to help boost dopamine levels in the brain.
The STEM-PD trial aimed to see whether stem cells, which had received the cue to turn into dopamine-producing brain cells, could replace some of the cells that are lost in Parkinson’s. This phase of the trial focused on finding the best dose of stem cells and how the body responded to the injection. They were also monitoring the health of the new cells, and whether they could survive in the brain.
They did this by implanting the stem cells via injection directly into the brain tissue of 8 people with Parkinson’s. One of these people was Andy, a research volunteer:
"The surgery took place in October 2024, in a hospital in Sweden. It was a 12-hour procedure under general anesthetic.
"Being part of the research meant that every 6 months, I go through lots of tests. For me, that was a way to track how my condition was changing. By repeatedly doing the same tests, I could notice any differences over time.
"My hope is that it will provide a 'top-up' of the cells I’ve lost. I know I’ll still have Parkinson’s, and the underlying cause of my brain cells dying won’t go away. But I hope this transplant will give me many years, or even decades, of dopamine-producing cells."
Participants were followed up for a year post surgery. During this time, they had to take immunosuppressants to make sure the implanted cells were not rejected by the body’s immune system.
What do the results show?
One year after the surgery, 7 out of the 8 participants were examined to see their progress. The final participant unfortunately died during the year as a result of an infection unrelated to the trial.
Brain scans from all 7 examined participants showed that the cells had implanted well in the brain area, and there were no unexpected side effects as a result of the surgery.
Excitingly, 6 out of the 7 participants also said that they had reduced their dopamine medication following the surgery, and reported a reduction in their Parkinson’s symptoms.
Read the full scientific results on the Nature Medicine website.
What happens next?
All participants will be continually monitored for the next 2 years, to see how the implanted cells survive over a longer time. They’ll also look for changes in Parkinson’s symptoms, and whether there’s any improvement, or at least slowing progression of symptoms over this time.
Claire Bale, Associate Director of Research at Parkinson’s UK, said: "This is an exciting development for stem cell research and a great milestone based on decades of work. It’s fantastic to see the early results of this landmark trial looking so positive. The fact that 6 out of 7 trial participants were able to reduce their medication as a result of the treatment is particularly encouraging.
"While this is a small trial with a relatively short follow up period, and we will need to see longer term results to get a better understanding of the impact, it represents a significant step forward. It brings the promise of new, better treatments for the Parkinson’s community much closer to reality."
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