World-first trial indicates immunosuppression may help treat Parkinson’s disease
This trial is the first to show that broadly suppressing the immune system could have a beneficial impact in Parkinson’s disease.
Participants on the treatment reported an overall improvement in movement-related symptoms. This meant they found it easier to perform tasks such as moving around, writing, washing and dressing. These improvements were greater in female participants compared to males.
Additionally, patients with faster-progressing Parkinson’s disease showed signs of improved memory and thinking skills.
Importantly, the trial did not reveal significant safety concerns around using immunosuppression treatments in Parkinson’s disease. This will enable larger research studies of immune therapies for PD in the future.
Parkinson’s disease is the fastest growing neurological condition in the world, affecting over 10 million people. This is around 153,000 people in the UK. Although treatments exist to manage some symptoms, there are no cures and treatments do not slow disease progression.
The trial, called AZA-PD, included 66 people with early-stage Parkinson’s disease. It investigated the effects of the drug Azathioprine, which suppresses the immune system. Azathioprine is already widely used to treat conditions such as rheumatoid arthritis and inflammatory bowel disease.
Existing research has shown that the immune system is over-active in people with Parkinson’s disease. This trial indicates that targeting immune activation might be a useful strategy for the treatment of Parkinson’s and provides impetus for further research to confirm these results in larger groups of patients.
Participants on the trial were treated with Azathioprine or a placebo for 12 months and were then followed up for another six months. Assessments looked at various movement and non-movement related symptoms of Parkinson’s disease as well as assessing safety of treatment.
One of the reasons Parkinson’s disease has proved so challenging to treat is because the brain is surrounded by a structure called the blood-brain barrier that protects against infections. Many drugs cannot cross the barrier.
During the trial, the effect of the drug on the immune system was measured in both the blood and brains of participants. It showed that, although Azathioprine cannot cross the blood-brain barrier, it acts indirectly to slow progression of inflammation in the brain, and this could explain its effects in Parkinson’s disease.
The results were presented by Dr Julia Greenland, a neurology specialist trainee at Cambridge University Hospitals NHS Foundation Trust (CUH) and clinical research fellow at the University of Cambridge, at the International Conference on Alzheimer’s and Parkinson’s Disease and Related Neurological Disorders (AD/PD) held in Vienna, Austria.
The study is led by Dr Caroline Williams-Gray, honorary consultant neurologist at CUH and principal research associate at the University of Cambridge. Dr Williams-Gray is also leading the DAPA-PD study, which is expected to open recruitment soon.
This trial aims to test whether dapansutrile, a drug which targets a more specific component of the immune system implicated in Parkinson’s, could also be a safe and effective way of treating the condition.
Dapansutrile is a new drug recently developed by Olatec Therapeutics. The AZA-PD trial has been funded by the Cambridge Centre for Parkinson-Plus and Cure Parkinson’s with support from the National Institute for Health and Care Research (NIHR) Cambridge Biomedical Research Centre (BRC) (NIHR203312), the Cambridge Clinical Trials Unit (CCTU) Neuroscience Theme and the core CCTU.
Dr Williams-Gray said: “There are currently no therapies available to cure or slow the progression of Parkinson’s disease. We know that inflammation in the brain is a factor but this is the first time we’ve been able to show that we can address this by suppressing the immune system with the potential to deliver benefits for patients.”