Sorry for the slight delay in joining the conversation.
To answer your questions Mister X:
No, I'm not aware of any studies which have tested exenatide in genetic animal models of Parkinson's. I believe all the pre-clinical research to date has used toxin based models.
Most of this early work has been carried out by Dr Peter Whitton and funded by Parkinson's UK. You can read more about his work here:http://bit.ly/18hxXzf
The results from the brain scans were inconclusive overall. From the paper:
"All exenatide group patients had profoundly abnormal scans at baseline, with some variation in severity of presynaptic dopaminergic deficit. 2 patients with severe baseline presynaptic deficits had minor improvement at 12 months. 1 individual had deterioration in all subregions. Mean values for absolute and percent changes in [123I]FP-CIT activity showed minimal change in all basal ganglia subregions in the exenatide group at 12 months."
Three people dropped out of the trial in total. One because of interference with their medication - the medication was not specified but exenatide slows stomach emptying so the team believe that was the problem. One withdrew because of changes in their sense of taste, and another because of excessive weightloss.
When will follow-up trials start?
That's the million-dollar question. We don't know yet but we'll be keeping a very close eye out for any developments and will let people know of any news through our website and magazines.
If you'd like to read the full scientific paper it's available here:http://www.jci.org/articles/view/68295
Hope that helps