Phase 3 trial of ambroxol is underway

In 2023 we announced we would be joining forces with Cure Parkinson’s, alongside its strategic partners Van Andel Institute (VAI) and the John Black Charitable Foundation (JBCF) to co-fund a clinical trial called ASPro-PD looking at the potential of a cough medicine called ambroxol to treat Parkinson’s.

After initial delays, we’re now pleased to share that the first participant has started on the ASPro-PD study, which will involve them taking either ambroxol or a placebo (dummy) drug. This marks an exciting start for the study, which will assess whether ambroxol could slow or even stop the progression of Parkinson’s.

What is ambroxol?

In 2009 researchers discovered that a medicine commonly used to treat coughs and sore throats, ambroxol, could also be used to treat Parkinson’s.

Ambroxol boosts levels of an enzyme called GCase, which is known to help clear away waste products which have gathered in brain cells. In Parkinson’s, a build up of a troublesome protein called alpha-synuclein is often seen in the brain tissue. It’s thought that ambroxol may help improve the body’s ability to clear away these clumps of alpha-synuclein and prevent damage to brain cells.

The ASPro-PD trial is a world-first phase 3 trial of ambroxol. Driven by Cure Parkinson’s, following 8 years of work with the Parkinson’s community, this £5.5m trial offers hope that a drug to slow the progression of Parkinson’s may be on the horizon.

What are the next steps?

Over the coming months 330 people with Parkinson’s will receive ambroxol and or a placebo 'dummy' drug for 2 years. After this, all participants will be given ambroxol for 6 months.

Neither participants nor their doctors will know whether they are receiving the trial drug or the placebo drug. Both ambroxol and the placebo drug will be taken in the form of a tablet 3 times a day.

As participants will be taking the drug for over 2 years, it’s likely we won’t know the results for a while. But this is a phase 3 trial, which is the last large study a drug must go through before it’s decided whether it can be approved for use.

Professor David Dexter, Director of Research, said:
"It’s very exciting to see the ASPro-PD trial move forward and start recruiting participants. This is the first large phase 3 trial that we have funded through the Parkinson's Virtual Biotech. If this is a success, ambroxol has the potential to be available in years and not decades."

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How can I get involved?

The ASPro-PD research team is reaching out to people who are eligible to take part and who have already pre-registered through the PD Frontline study. This is a study where people are asked to supply a saliva swab, which is then studied to look for changes in certain genes.

People who meet the criteria for ASPro-PD, and have already taken part in PD Frontline will be invited to visit one of 15 study sites over England, Scotland and Wales. You will be contacted directly if you fit these criteria. 

If you haven’t already registered and taken part in PD Frontline, you may not be able to join the ASPro-PD study. However, you can still register to get genetically tested by PD Frontline and explore other research opportunities through the Take Part Hub. Search the Take Part Hub.

Ambroxol isn’t currently recommended for Parkinson’s

Whilst past trials have shown promise, there is still more research needed to show if ambroxol can be a safe and effective treatment for Parkinson's. This includes safe testing of dosages and frequencies. Parkinson's UK does not recommend you take any medications without a prescription. You can find answers to other questions about ambroxol and the ASPro-PD trial in these frequently asked questions. Read the frequently asked questions.