University College London has begun a two-year clinical trial to test if cough medicine ambroxol slows down Parkinson’s.

The drug, called ambroxol, may remove damaging proteins from the brain that cause degenerative diseases. Currently, there is no treatment for the neurological condition, which impacts cells in the part of the brain that regulates movement.

This is the closest scientists have come to developing a Parkinson’s treatment, according to experts.

Brief background on Parkinson’s disease

Parkinson’s is the world’s fastest-growing neurological condition. It can affect anyone at any age. 

For 60 years, people with Parkinson’s have been relying on the same drug, called levodopa, to help control some of the symptoms, but levodopa doesn’t slow, stop or reverse Parkinson’s progress. Over time, levodopa becomes less effective as symptoms worsen. 

People with Parkinson’s can experience many symptoms, including problems with movement, speaking, disrupted sleep, severe muscle cramps, extreme pain and problems with brain function [1].

What is ambroxol?

Ambroxol has been commonly used to treat coughs and sore throats across Europe since 1973.

As both a pill and syrup, the medicine eases coughing by clearing away mucus in the lungs of patients with respiratory illnesses. The drug also increases the brain’s level of glucocerebrosidase, or GCase.

In Parkinson’s patients, alpha-synuclein builds up in the brains, causing symptoms such as involuntary shaking, slow movement, stiff joints and involuntary shaking, according to scientists. GCase is crucial to removing this substance.

Repurposing ambroxol for Parkinson’s

Recently, a research group in Russia looked at the cellular waste disposal process in blood cells collected from people with either Parkinson’s or Gaucher disease. They found that ambroxol treatment improved the disposal of waste from blood cells.

Gaucher disease has many biological similarities to Parkinson’s, one being a dysfunctional waste disposal system from cells. This causes a build-up of unwanted waste products in cells, and it is thought this contributes to the physical symptoms of each disease. 

Interestingly, people with Gaucher disease have a higher risk of developing Parkinson’s later in life and many people with Parkinson’s carry some of the tiny mutations in their DNA that are associated with Gaucher [2].

Given this close relationship, researchers have been searching for medications that might help both conditions – one such treatment could be the cough medication ambroxol. Widely used to reduce inflammation in the chest, ambroxol has exhibited very encouraging results in models of both Parkinson’s and Gaucher disease.

In addition, another group of researchers have recently presented “real world” data. They have evaluated the outcomes of people with Gaucher disease or Parkinson’s being treated ‘off-label’ with ambroxol. 

Off label means using a drug for a condition that regulators have not approved it for. The researchers analysed 41 patients with either Gaucher disease or Parkinson’s who were treated with ambroxol, and they found that more than half of them (25) improved; they had improved physical activity and reduced fatigue.

This accumulating data provides further justification for testing ambroxol in people with Parkinson’s. A phase 2 clinical trial supported by Cure Parkinson’s has reported encouraging results and now preparing the next step in the clinical development of this drug for Parkinson’s.

Ambroxol trial for Parkinson’s

A new trial called ‘Ambroxol to Slow Progression in Parkinson’, or the ‘ASPro – PD’, will occur at up to 12 hospitals in the UK.

There will be 330 patients with Parkinson’s participating in the study. Ambroxol will be administered to half of the participants for two years, while a placebo will be administered to the other half. A comparison of the participants’ quality of life and movement will be conducted at the end of this period, and researchers will evaluate the progression of Parkinson’s in the two groups.

Working on better treatments

In the UK, there are more than 140,000 people living with Parkinson’s. It is still unknown what triggers it, and there is no cure, but patients can take drugs that reduce the main symptoms. ‘This will be the first time a drug is being tested for a specific cause of Parkinson’s disease,’ says University College London professor Anthony Schapira.

Parkinson’s UK’s associate director of research, Professor David Dexter, agrees: “People with Parkinson’s desperately need better treatments.” With this trial’s success, ambroxol may be available soon, not decades from now. 

[1] https://cureparkinsons.org.uk/ambroxol-and-parkinsons/
[2] https://cureparkinsons.org.uk/research/the-scientific-justification-for-the-repurposing-of-ambroxol-for-parkinsons/
[3] https://www.dailymail.co.uk/news/article-11635993/UCL-launches-clinical-trial-test-cough-medicine-ambroxol-slow-Parkinsons-disease.html