Participants on the Exenatide-PD3 study, a phase 3 clinical trial of diabetes drug exenatide (Bydureon), have now learned the results from the lead investigator, which indicate that the study did not meet its primary endpoint.

The primary endpoint is the predetermined measure of success researchers set when creating a clinical trial; in the case of Exenatide-PD3, this was whether there were changes in participant’s motor symptoms throughout the duration of the trial. The results indicate that there was no significant difference in the progression of motor symptoms between the treatment and placebo groups (those not taking active drug). There was also no difference between the groups with any of the other measures included in this trial.

These results have now been submitted to a scientific journal and we await the publication of the full results.

The study team is now working to understand the disconnect between the encouraging phase 2 results with exenatide, the clinical success in Parkinson’s patients of another GLP-1R agonist lixisenatide, and these new phase 3 results with exenatide. They also are working to identify all learnings from this trial to inform future research in the GLP-1 field and beyond.  Results of two sub-studies, funded by Cure Parkinson’s with Van Andel Institute, are still forthcoming as well, which sought to gather additional evidence on how the drug interacts with cells and whether a wearable device and smartphone app can be used to help track motor symptoms.

Read more about the Exenatide-PD3 substudies

The first sub-study Cure Parkinson’s funded (thanks to support from the Frank Brake Charitable Trust) alongside Van Andel Institute (VAI) was a brain imaging study. This will allow researchers to quantify the levels of dopamine neuron branches in the brain of participants at the start and then at the end of the trial. This gives a measure of the health of dopamine producing neurons in the brain, and will show if exenatide is preventing their deterioration.

The second sub-study has used smartphone app  to gather day-to-day information about trial participants’ motor functions (their everyday movements), their tremor and their walking speed. The app was developed by Professor Michele Hu at Oxford University. The sub-study will help the team to mediate variability in movement symptom scoring by assessors in different hospitals during the trial and will also test whether apps might be a better way to assess Parkinson’s movement symptoms in future studies or in clinical check-ups.

What was Exenatide-PD3?

The phase 3 Exenatide-PD3 study was a UK-wide clinical trial that evaluated whether a diabetes drug exenatide (Bydureon) may slow the progression of Parkinson’s. Funded by the National Institute for Health and Care Research (NIHR), the trial was made possible thanks to the commitment of 194 individuals with Parkinson’s, and was conducted over 96-weeks. Exenatide is a GLP-1 receptor agonist, which is a class of drugs used in the treatment of Type 2 diabetes. Two phase 2 clinical trials of GLP-1 receptor agonists have provided encouraging positive results and supported the phase 3 testing of this agent.

Every volunteer in research is so important and truly makes a difference to the future of Parkinson’s. Without them, we simply could not find treatments with the potential to slow or stop disease progression.

“This study was made possible by the dedication and commitment of the incredible 194 participants, whose contribution and willingness to share data is so important to Parkinson’s research. When studies reach phase 3, we all hope that the findings at earlier phases will be replicated and amplified. This is not the news any of us — study participants, investigative team and those funding and leading related work — wanted to hear.  

While the overall result is not as we’d hoped, there is so much we can still learn from the trial data that will help inform future research. There are many promising drugs in the pipeline, and we at Cure Parkinson’s alongside our partners will continue without delay to prioritise, fund and facilitate the testing of these potential new treatments.”

– Helen Matthews, CEO, Cure Parkinson’s