More about exenatide (GLP-1 agonist)

When the results of a Phase 3 trial of a GLP-1 agonist were first released, I shared the disappointment that the study showed the drug had no effect on people with Parkinson's. In earlier studies, there were hints that the drug could reverse disease progression, but I consider those hints to be relatively subtle ones. My negativism is based in part on the data showing that while the doctors thought the patients improved but the patients did not notice any improvement (and thankfully did not worsen either).

Reviewing the laboratory science is really interesting. Data show that neurons can behave almost as though they are pre-diabetic - which is called "insulin resistant." It makes sense that the GLP-1 drugs would help if this were a major part of the disease.

But when I read the data, it is not so clear that this is a problem specific to Parkinson's. Data suggest that the problem is evident in laboratory models of Alzheimer's and Parkinson's. So that makes me wonder, is insulin resistance a non-specific indicator of brain cells that are degenerating, rather than something related directly to Parkinson's disease?

Let's remember that so many Parkinson's experts seem to reject the view that you can lump diseases together. They advocate that we focus on the variability between the way the disease manifests in different individuals and identify ways to treat each specific manifestation of the disease in its own personalized way. But you can't have it both ways.

And for the record, I believe the way to conquer Parkinson's is to get outside the normal, traditional views - the ones that are not working - and look for unifying mechanisms that can be addressed. That's what we are doing.