A special edition of our annual clinical trial report has now been published in the Journal of Parkinson’s Disease (JPD), providing an overview of the Parkinson’s clinical trial landscape from 2015 to 2024. The report was produced by the Cure Parkinson’s research team in collaboration with Parkinson’s research advocates led by Susan Buff and The Michael J. Fox Foundation.
Since 2020, Cure Parkinson’s has collaborated with Parkinson’s research advocates and the Michael J. Fox Foundation (MJFF) to produce an annual analysis of the Parkinson’s clinical trial pipeline. To date, five reports have been published between 2020 and 2024.
Last year, this work expanded further with an ambitious analysis assessing the completed and ongoing Parkinson’s clinical trials of the last ten years, focusing only on trials using drugs. The aim was to understand the progress being made by the global Parkinson’s research community into development of a cure as well as better symptomatic treatments, to identify trends and learnings from these efforts, and highlight opportunities for future research and funding.
10 years of Parkinson’s clinical trials
The analysis showed that 444 Parkinson’s drug clinical trials were initiated between 2015 and 2024. Of these, 133 were still ongoing as of 16 January 2025, while just over half had been completed.
The trials tested 281 different drug interventions, as many treatments were evaluated in more than one trial. Just over half of the trials (52%) assessed novel drugs, 33% investigated drugs already approved for other conditions, and the remainder explored reformulations or new delivery methods for existing Parkinson’s treatments.
Nearly two-thirds of the trials (63%) focused on treatments to manage symptoms, while 37% were striving for disease modification, treatments aimed at slowing or stopping the progression of Parkinson’s. Encouragingly, the number of disease-modifying trials increased over the decade and accounted for more than half of all new trial registrations between 2022 and 2024.
What therapy targets are researchers investigating for Parkinson’s?
Most symptomatic therapies targeted motor symptoms using reformulations of levodopa and dopamine agonists, which are the main current options for treating motor symptoms of Parkinson’s. In contrast, relatively few therapies were being tested for non-motor symptoms such as sleep problems, constipation, depression and anxiety, highlighting an important area of unmet need.
Among disease-modifying therapies, researchers pursued a range of biological targets. Almost 14% focused on alpha-synuclein, the protein that builds up in Parkinson’s, while others targeted inflammation, mitochondrial function and energy metabolism, the gut microbiome, oxidative stress, and genetic forms of Parkinson’s such as GBA1 and LRRK2. Additional approaches included GLP-1 receptor agonists, neurotrophic factors and cell therapies.
The wheel above provides a summary of all the therapies in active clinical trials for Parkinson’s as of 16 January 2025. The wheel is divided in half, with the upper section focusing on therapies with the potential to slow, stop, or reverse Parkinson’s progression and the lower section being therapies targeting Parkinson’s symptoms. The therapies are color-coded based on which aspect of Parkinson’s biology they target.
In terms of development stage, 42% of the trials were in phase 1, 46% were in phase 2, and only 12% had progressed to phase 3, the final stage of clinical testing. Although the increase in disease-modifying trials is encouraging, only nine had reached phase 3, highlighting the challenge in progressing potentially disease-modifying treatments through final phases of clinical testing.
None of this progress would have been possible without the more than 39,000 people who took part in Parkinson’s clinical trials around the world over the past decade, helping to move us closer to better symptomatic treatments and, ultimately, disease-modifying therapies.
The impact of the International Linked Clinical Trials (iLCT) programme
The iLCT programme, created by Cure Parkinson’s and Van Andel Institute in 2012, is a global drug selection programme focused on speeding up the search for disease-modifying treatments for Parkinson’s. Once a year, a committee of over 20 world-leading Parkinson’s experts meet to discuss and prioritise potentially disease-modifying treatments for clinical trials in Parkinson’s.
The impact of the iLCT programme can clearly be seen in the Parkinson’s clinical trial pipeline over the past decade. Of the 133 trials that were still active as of 16 January 2025, more than 31% of disease-modifying trials were associated with drugs that had previously been evaluated by the iLCT committee.
Cure Parkinson’s is proud to have been a supporter of many of the clinical trials on this list, including the phase 3 clinical trials of ambroxol and exenatide.
