Updates from the UK's largest trial of treatments to slow Parkinson's
One year since the EJS ACT-PD study launched, we take a look at the progress made so far.
In 2025, we announced the launch of the largest ever Parkinson's research clinical trial to date. The trial is testing multiple therapies that all have the potential to slow, or even stop Parkinson's getting worse.
The Edmond J Safra Accelerating Clinical Trials in Parkinson's (EJS ACT-PD) is a revolutionary research trial, aiming to save time when testing treatments that have the potential to stop or slow Parkinson's progression. It will do this by testing multiple treatments at the same time, in a trial format known as a multi-arm, multi-stage, or MAMS.
We're proud to continue supporting and co-funding the trial as it starts its second year. Take a look at some of the progress over the past year.
Massive community response
There has been a phenomenal response from members of the Parkinson's community coming forward to express interest in being part of the trial, with over 2,200 people having registered their interest.
Research sites are continuing to open across the UK, with 26 sites open so far. The study team plans to keep expanding, with a total of 40 sites in preparation. You can find a full list of the planned sites on our Take Part Hub Page.
Satvinder is taking part in the trial in Bath. He shared: "I've had lots of time with the team just to check in on how things are going, and if there are any concerns I can relay that back.
"That two-way conversation has been phenomenal. You're not on your own. It's been really good."
Adding a new drug to the trial
The study launched last year with 2 treatments, telmisartan and terazosin, which have both previously shown signs in the lab and in early clinical testing that they could slow the progression of Parkinson's - something no treatment can currently do.
Everyone who has started on the trial so far will continue to take either drug or a control drug, known as a placebo, once a day alongside their normal medication and support.
Now, the research team has reached another important milestone. This month, they are adding another treatment to the trial, called ursodeoxycholic acid (UDCA).
UDCA is a medication currently used to treat liver disease. Work that we funded, led by Professor Heather Mortiboys at the University of Sheffield in 2013, suggested it could also have potential to treat Parkinson's. It could do this by protecting the mitochondria of the brain cells, which are responsible for providing the cell with enough energy to do its job. Damage to the mitochondria has been linked to cell death in Parkinson's.
Further testing led to a phase 2 study of the drug, which showed it was safe and led to some improvement in the mitochondria. Read more about the phase 2 study in our news story.
Testing UDCA will look slightly different to the first 2 drugs included in the study. This is because participants will need to take either 3, 4 or 5 tablets throughout the day, depending on their weight, to ensure they get the correct dose.
What's next?
From now on, anyone who joins the EJS ACT-PD trial will be allocated into 1 of 5 groups: 2 placebo groups, and 3 drug groups
You can find out more about the details of the trial in our frequently asked questions document.
Dr Becky Jones, Research Communications Lead at Parkinson's UK, said:
"It's great to see things moving forward with EJS ACT-PD and build momentum. The addition of UDCA is a great step forward that shows the trial is doing what it set out to do - test multiple treatments in order to speed up Parkinson's research.
"There has been a fantastic response to the trial so far and we're very grateful to everyone who has come forward to register their interest. We'd like to thank each and every person who has got in touch for your enthusiasm and your patience as the team works to open more sites and enrol more participants.
"While the initial response to taking part has been incredible, the team are particularly looking for people from Black, Arab, Asian and Mixed Heritage backgrounds as they are currently underrepresented in the trial.
"We're pleased to continue supporting the team as they begin the second year of this record breaking trial."
This clinical trial is sponsored and led by University College London and is funded by a Medical Research Council (MRC) and National Institute for Health and Care Research (NIHR) partnership, Cure Parkinson's, The Michael J Fox Foundation, Parkinson's UK, The John Black Charitable Foundation, The Gatsby Charitable Foundation and Van Andel Institute.
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There are over 40 Parkinson's research studies on our Take Part Hub that need people like you. Search using your postcode to find studies you can take part in from home or at a site near you.
EJS ACT-PD is testing 3 drugs that are already used to treat other conditions. Find out why researchers are exploring existing drugs, such as UDCA, for their potential in Parkinson's on our research blog.