Largest-ever Parkinson’s disease trial opens across UK
16 Oct 2025
The world’s largest-ever clinical trial of treatments to slow or stop the progression of Parkinson’s disease has launched in the UK. The Edmond J Safra Accelerating Clinical Trials in Parkinson’s Disease (EJS ACT-PD) trial will test multiple treatments in parallel, accelerating the search for effective treatments by testing more drugs faster and more efficiently than ever before.
This innovative trial is led by researchers at UCL and Newcastle University. Its vision was enabled by funding from the Edmond J Safra Foundation, which brought together a team of researchers, academics, and charities working closely alongside people living with Parkinson’s to design a trial that will suit the needs of those who stand to benefit.
The EJS ACT-PD trial is using a multi-arm, multi-stage (MAMS) design, enabling several treatments to be tested in parallel in comparison to a single placebo group, a design that has not been used before for Parkinson’s. By analysing results on an ongoing basis, treatments that don’t work can be identified and dropped from the trial, with more promising candidates progressing to the final review. It also allows to introduce new treatments within the same trial infrastructure. Compared to running individual trials for each treatment, the design can accelerate the assessment process by close to 25% (or up to three years).
The trial will start by testing two drugs known to be safe and effective at treating other conditions: telmisartan, used to treat high blood pressure, and terazosin, commonly used to treat an enlarged prostate. The aim is to add a third drug, ursodeoxycholic acid (UDCA), currently used for liver disease, in 2026.
EJS ACT-PD will recruit 1,600 participants in the first phase from more than 40 hospitals across England, Wales, Scotland, and Northern Ireland. The trial is now underway, and participants are already being recruited at the sites in London and Newcastle, with the other trial sites to open over the next six months. People with Parkinson’s can complete a simple online form to register their interest in the trial.
People living with Parkinson’s, their partners and carers, and community representatives have been involved in every aspect of the trial design, and their input has had a major impact on the trial.
The trial is a huge endeavour, and the £26 million in funding secured is the largest amount ever for a Parkinson’s study in the UK. EJS ACT-PD 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. The trial is sponsored and managed by the MRC Clinical Trials Unit at UCL.
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