Dual drug therapy for Parkinson's

A collaborative initiative from Cure Parkinson’s sets out practical steps to encourage a combination therapy approach.

Medical research charity Cure Parkinson’s is calling for a change in how new Parkinson’s treatments are developed, after years of clinical trials testing monotherapies have yet to succeed in slowing, stopping or reversing progression of the condition. The charity is championing – and funding – a broader strategy for identifying disease-modifying therapies, in particular, the consideration of combinations of therapies, and has convened leading scientists to set out the case in a newly-published report. This approach is already established in cancer and infectious disease, but rarely attempted for disease modification in Parkinson’s.

No drug has yet been shown to change the underlying course of Parkinson’s, a condition affecting an estimated 11.8 million people worldwide. Existing medications, many based on the decades-old drug levodopa, treat symptoms such as tremor and stiffness but do not slow the condition itself. Finding a single molecule capable of doing so has proved difficult, which researchers say reflects the complexity of the condition and the number of biological pathways likely to be involved.

The recommendations, published as a meeting report in npj Parkinson’s Disease, are drawn from a workshop co-ordinated by Cure Parkinson’s in June 2025, which brought together academics, industry representatives, clinicians and people living with Parkinson’s as a collaborative initiative. Rather than prescribe a single strategy, the group set out practical steps the field could take now to give combination approaches a genuine chance of success, including:

Senior researchers should mentor early-career scientists to ask, for every drug candidate, whether it could be enhanced by combining it with another therapy, and whether its pharmacokinetics could be improved.
Funders should build questions into grant applications asking whether applicants have considered combining their agent with other therapies, particularly where a drug is known to have pharmacokinetic limitations.

Rather than screening for single targets, researchers should use CRISPR-based screening to identify which combinations of druggable targets show the greatest potential for combined benefit.
Funders should launch dedicated funding calls focused specifically on rationally designed combination therapies, rather than leaving the approach to emerge by chance.

Dr Rachel Hughes, Preclinical Research Manager, Cure Parkinson’s, and one of the paper’s key authors, says: “For years, the field has largely searched for a single drug that can change the course of Parkinson’s, and that search has proved more difficult and complex than anyone hoped. It is possible that no single molecule can address a condition as complex as this one. Combination therapies give us a way to target more than one biological pathway at once, and we’re urging researchers and funders to build that thinking into their work from the outset. We’re extremely grateful to everyone across the Parkinson’s community who took part in this workshop. Collaboration is key to finding a cure for Parkinson’s, and we’re delighted this work has now been published as a report.”

Dr Simon Stott, Director of Research, Cure Parkinson’s, adds: “Combination therapies represent a largely unexplored avenue for disease modification in Parkinson’s. However, other conditions made this shift years ago. For example, cancer and tuberculosis are both routinely treated with combinations, not single drugs. Parkinson’s research is only now catching up. Whilst this type of mindset shift might take time, we hope that by publishing the outcomes of this workshop, researchers within the Parkinson’s field will be inspired to evaluate their work and consider whether drug combinations could be explored earlier in the drug discovery process. While we remain hopeful for success in ongoing clinical trials and the introduction of several multi-arm, multi-stage (MAMS) trials, combination therapies are an additional approach that could improve the odds of finding a disease-modifying therapy.”

Professor Heather Mortiboys, Professor of Cellular Neuroscience and Metabolism and Workshop Chair, concludes: “Parkinson’s is a complex condition in the clinic and at the cellular level, meaning that each person with Parkinson’s is affected differently. This makes finding a single drug to treat Parkinson’s very difficult, and this has been shown by clinical trial results with monotherapies, or single drugs. Hence, it is essential that we work together as researchers, clinicians, funders and people affected by Parkinson’s to change our mindset, research and clinical trials and incorporate combination therapies into every aspect of Parkinson’s work. This offers us a better chance of finding disease modifying therapies. This report, and the work of Cure Parkinson’s in this area, is extremely important to raise awareness and change mindsets.”

Following the workshop, in March this year, Cure Parkinson’s announced a new evaluation panel to assess applications to their recent £2 million funding call for projects testing combination therapies for Parkinson’s. The funding call proposals included both preclinical and clinical projects testing rationally designed combination therapies. The panel has evaluated submissions to ensure they are scientifically sound, align with Cure Parkinson’s mission and provide results that are meaningful to the Parkinson’s community. An announcement on the projects funded through this call is expected within the coming months.