Hikoi, to whom my thanks, has posted on the Parkinson's Movement/HealthUnlocked forum that the initial results of the latest GDNF trial have been reported [1]:

"Phase 2 clinical trial evaluating the safety and efficacy of glial cell line-derived neurotrophic factor (GDNF) in Parkinson's disease, delivered via intermittent bilateral intraputamenal infusions using convection enhanced delivery (CED) ... did not meet the primary efficacy endpoint."

The Parkinson's UK position is [2]:

"These initial findings appear disappointing but the full results and analysis may yet reveal positive insights."

There has been a long history of claim and counter-claim about the efficacy of GDNF, but I think that this puts an end to the chances of GDNF being part of a useful therapy for PD.

References:

[1] News

[2] Parkinson's UK - Update on GDNF trial: analysis underway

John