Our popular and much-awaited research update meeting brought together two leading clinicians to report on their individual area of expertise for Parkinson’s – one in dopamine cell replacement therapy and one in a drug intervention called ambroxol. If you were unable to attend, the meeting and the Q&A sessions were recorded for you to watch again.

Dopamine cell replacement therapies for Parkinson’s – where are we now? Prof. Roger Barker

The ASPro-PD phase 3 clinical trial of ambroxol: update and panel discussion with Prof. Anthony Schapira

Frequently asked questions from the meeting:

Dopamine cell replacement therapy – Professor Roger Barker provides answers

How long will it be before dopamine cell replacement is available for everyone living with Parkinson’s?

We are on the cusp of a breakthrough with this therapy. There are several clinical trials of dopamine cell replacement grafts going on around the world now and we will know within the next five years whether this therapy works. The time, however, between these results and a clinical therapy for all is not so clear cut and depends on many factors including regulatory approval and pharmaceutical company support.

There are a significant number of private clinics opening up around the world offering stem cell treatments for Parkinson’s – are they safe?

No – we would not recommend using these. These clinics are often offering stem cell treatments, with no evidence that they work or how they could work. The rationale for our specialised dopamine cell replacement therapy is now being tested in people with Parkinson’s with a background of many years of lab work, and as you would expect our trial has rigorous and robust safety regulations in place. Until this line of treatment is thoroughly tested and proven to work, ‘stem cell tourism’ is not a safe bet to pursue.

Are you looking for volunteers for the current STEM-PD cell replacement therapy trial to test the procedure? What are the main criteria to participate?

STEM-PD has started and the first patient was grafted this month (February 2023) and we hope to graft seven more patients over the next 18 months. There will then, it is hoped, be another study called TRANSCEND that will start grafting cells into patients in 2024. We will most likely be looking in such trials for people who have had Parkinson’s for about 10 years, who are under 70 years of age and who have responded well to dopamine drugs without major problems with dyskinesia or freezing of gait, or big thinking and memory problems.

What if dopamine based drugs are not tolerated well by a person with Parkinson’s? Are any of these therapies potentially going to be of benefit to them?

If individuals do NOT respond to dopamine drugs, then no. If they cannot tolerate dopamine drugs then they may be suitable for dopamine cell transplants but it will have to be shown somehow that a form of oral dopamine therapy has helped them in a clear and objective way.

Can people who have had Deep Brain Stimulation (DBS) be considered for dopamine cell replacement grafts?

Currently, researchers are not considering individuals who have had DBS for dopamine cell replacement grafts. However, in the future, this may be an option – but if cell replacement works then it is hoped that person with Parkinson’s will not need DBS!

Why are the costs of dopamine cell replacement therapy so high?

The health economics are a concern with this potential treatment line and ultimately, if this works, we know that the costs will determine who will be able to have it. There is, however, no reason to think that these costs will be prohibitively high because the cells for grafting into patients are not that expensive to make, and a lot of such cells can be made relatively quickly.

How harsh is the immunotherapy needed to stop rejection of these implanted cells?

It is same as for a kidney transplant but will only be for one year post grafting (not life long as for kidney transplants). As such we think this will be well tolerated and not cause too many side-effects or problems.

Could DNA testing help to decide on who would benefit from the therapy, and which therapy would be the most effective?

In the future yes, but for the moment we do not know whether there is a specific gene or genetic signature that marks someone out as a good or bad candidate for this type of therapy. However, we are taking DNA from all our grafted patients so will look at this as the programme evolves.

The ASPro-PD phase 3 clinical trial of ambroxol

What is PD Frontline?

PD Frontline is an easy online genetic screening study that is simple to do. All individuals wishing to take part in the ASPro-PD phase 3 trial of ambroxol must be screened via PD Frontline. The study will determine if participants have a mutation in a part of their genes called the GBA gene – one of the risk factors for Parkinson’s. The ASPro-PD trial will be testing the drug ambroxol in people with Parkinson’s who have this GBA mutation and, importantly, those people with Parkinson’s who do not have it.

Can people with Parkinson’s take part in the STEM-PD trial as well as the ASPro-PD trial?

Unfortunately, it is not possible to take part in both of these trials at the same time.

At Cure Parkinson’s, we are supporting the multi-arm multi-stage (MAMS) trial process for Parkinson’s where individuals taking part in a MAMS trial will be enabled to move between trial arms depending on how well the trial is progressing and how well individuals are responding to the trial drug.

Is the ASPro-PD trial as simple as people with Parkinson’s taking a cough medicine?

It is a bit more complex than simply taking cough medicine as the dosage is much higher than standard. Cure Parkinson’s and the research team including Professor Anthony Schapira, the lead researcher, have been working carefully to determine the requisite dose to achieve efficacy in this trial. Importantly, this dose will need to be rigorously tested.

Does taking L-dopa and other symptom management drugs prevent people with Parkinson’s taking part in the ASPro-PD trial?

No, Parkinson’s medications do not prevent taking part. Indeed, the trial team are keen to assess the impact of these medicines on participants and see this as part of the overall trial learnings.

What are the success criteria for the ASPro-PD trial?

The primary endpoint for this trial is to understand what people with Parkinson’s themselves feel and experience following completion of the study, along with some objective measures, so it is a combination of these.

How long will the trial take?

We are allowing a two year period to recruit all 330 people, then the trial will take two years to complete, then the analysis begins. It is important therefore that we recruit people with Parkinson’s as soon as possible to expedite this process.