Parkinson’s trial EJS ACT-PD adds a new treatment arm
04 Nov 2026
The EJS ACT-PD (Edmond J Safra Accelerating Clinical Trials in Parkinson’s Disease) trial, the world's largest-ever clinical trial of treatments to slow or stop the progression of Parkinson's disease, is expanding to test a third potential treatment, ursodeoxycholic acid (UDCA).
EJS ACT-PD uses a multi-arm, multi-stage design which enables several potential treatments to be evaluated within a single trial. This approach allows researchers to identify promising treatments more quickly and efficiently than traditional clinical trials.
Since the trial opened to recruitment, participants have been randomised to receive either telmisartan, terazosin or a matched placebo. Both medicines are already licensed to treat high blood pressure and also showed promising evidence as potential treatments for Parkinson’s disease.
Researchers now will investigate whether ursodeoxycholic acid (UDCA) could also help slow progression of Parkinson’s disease. Like telmisartan and terazosin, UDCA was selected following an extensive scientific review that assessed hundreds of potential therapies and identified those with the strongest evidence for slowing Parkinson's disease progression.
UDCA has been used safely for many years to treat certain liver conditions. Research suggests it may also help protect brain cells by improving mitochondrial function, the process by which cells produce energy. Problems with mitochondrial function are thought to play an important role in Parkinson's disease. Previous clinical studies have also reported encouraging improvements in walking and mobility among people living with Parkinson's who received the treatment.
EJS ACT-PD has now opened at 26 NHS sites across the UK, with more than 189 participants already randomised. The trial has generated strong interest from the Parkinson's community, with more than 2120 people registering their interest in taking part.
The trial is led by researchers at UCL and Newcastle University and is sponsored and coordinated by the UCL Innovative Clinical Trials Unit (InCTU). It is funded through a partnership between the Medical Research Council (MRC) and National Institute for Health and Care Research (NIHR), with additional support from Cure Parkinson’s, The Michael J Fox Foundation, Parkinson’s UK, The John Black Charitable Foundation, The Gatsby Charitable Foundation, and Van Andel Institute.
Further information: