To date no therapy has shown disease-modifying effects in clinical trials in Parkinson’s disease.
In a trial published in the Lancet (online, 3 August 2017), researchers randomly assigned 62 patients with moderate Parkinson’s disease to receive 2mg of the glucagon-like peptide-1 (GLP-1) receptor agonist exenatide or placebo once a week for 48 weeks
After a 12-week washout period, the researchers found that off-medication motor function (as measured by the Movement Disorders Society Unified Parkinson’s Disease Rating Scale) improved from baseline by 1.0 point in the exenatide group (95% confidence interval [CI] -2.6 to 0.7) and worsened by 2.1 points in the placebo group (-0.6 to 4.8). The difference in scores between the two groups, -3.5 points (-6.7 to -0.3; P=0.0318), was statistically significant.
The team says the findings indicate a major new avenue for investigation in the treatment of Parkinson’s disease but further research is needed to determine whether exenatide affects disease progression or improves quality of life.
 Athauda D, Maclagan K, Skene S et al. Exenatide once weekly versus placebo in Parkinson’s disease: a randomised, double-blind, placebo-controlled trial. Lancet 2017. doi: 10.1016/S0140-6736(17)31585-4