Exenatide had no disease-modifying effects in a phase 3 trial Parkinson’s disease, despite earlier evidence from a phase 2 study suggesting a potential role for GLP-1 agonists in PD.

The GLP-1 receptor agonist exenatide failed to meet its primary outcome in a phase III trial of Parkinson's disease patients. Weekly injections of the GLP-1 receptor agonist exenatide (Byetta, Bydureon) did not slow Parkinson's disease progression or improve symptoms, the phase III Exenatide-PD3 trial showed.

Treatment with exenatide, a GLP-1 receptor agonist, was comparable to placebo in slowing the rate of Parkinson’s disease progression over 96 weeks of treatment, according to a phase 3 study published in The Lancet.

I wouldn’t do another study like this unless you learn what is the target,” Dr. David Standaert, a Parkinson’s researcher at the University of Alabama at Birmingham, told

The study may suggest that other researchers should be less optimistic about the prospects for treating a range of other conditions with newer weight-loss drugs.