We completely agree that it takes too long for people to benefit from research into new medications. That's why our Research Vision is to make new and better treatments available in years not decades. Let's take a look at some of the issues in the pursuit of repurposed drugs.
Why is more research needed?
For exenatide, a phase 3 trial would be needed to establish the drug works and check for any adverse effects in a large number of people. This is particularly important in Parkinson's where people experience very different symptoms. It could be that some people with certain symptoms won't benefit from the treatment, or worse could experience side effects.
Another consideration is how long someone will need to take the drug for. Some drugs may be safe to take short term but have side-effects, or become less effective when taken for longer periods, which would likely be needed to treat Parkinson’s. Drugs may also interact with each other — reducing the effectiveness of other medications or causing unwanted side-effects.
So even approved drugs need to go through the clinical trial process to make sure they are safe for people with Parkinson’s. However, for repurposed drugs, this can be a much quicker process that those developed from scratch. We already know much about these drugs so they may skip earlier stages and move into the later phases of trials more swiftly, and be made available quicker.
So, where are we at with exenatide?
The latest results came last August. There's a brilliant review of where we are so far from Parkinson's researcher Simon Stott https://scienceofparkinsons.com/2017/08/08/exenatide-an-editorial/ and also our blog on these results here https://medium.com/parkinsons-uk/exenatide-latest-trial-results-explained-ef72fbee3c44 if you haven't already seen them.
But briefly, results so far are looking good and the next stages are being planned. We believe the academics are in discussions with regulators for a phase III study. Like you we are eagerly awaiting more news and, as further research will likely require many more participants, hope to be able to share opportunities to take exenatide by taking part in the trial
But will these drugs ever be made available?
The issue with profitability of repurposed drugs is undoubtedly a major hurled for bringing these often 'off patent' drugs to market (i.e. into the hands of the people who need them). But it's not just an issue for Parkinson's.
We are doing all we can to improve the pathway to making drugs like exenatide available - you can read about how we are working with the Government and other charities to do this in our latest blog post: https://medium.com/parkinsons-uk/making-repurposed-treatments-a-reality-5c811d0b413b
And there has also been progress in speeding up the delivery of new breakthrough treatments: https://www.parkinsons.org.uk/news/fast-track-route-medicines-and-technology-announced
If you would like to help support this kind of activity, I would recommend finding out about our policy and campaigning work. This is a different way you can help support the charity that does not require a financial donation https://www.parkinsons.org.uk/get-involved/campaign
Despite the hurdles, there are successes in the history of drug repurposing – such as sildenafil, an angina medication developed in 1989 now more commonly known as Viagra, and azidothymidine, which failed as a chemotherapy drug but because a HIV medication in the 1980s. Both industry and academic researchers are devoting more resource in the pursuit of repurposed drugs and progress is being made to help these drugs get to market.
We will continue to do all we can to deliver new and better treatments faster, and, as everything we do is led by people affected by Parkinson's, I hope that you will continue to engage in conversations like these to make sure we are addressing the issues.
With very best wishes for 2018,
The Research Team