Parkinson disease and growth factors — is GDNF good enough?

Abstract

Previous open-label trials testing glial cell line-derived neurotrophic factor (GDNF) family ligands in Parkinson disease have shown promising clinical effects. However, in placebo-controlled trials, the treatments have failed. A new randomized placebo-controlled trial of intraputamenal delivery of GDNF designed to resolve this conundrum has again failed to do just that.