Shetawk, this is a really really old article from 2002.

http://news.bbc.co.uk/2/hi/science/nature/1935593.stm

They have done larger clinical tests with it but they aborted it in 2004. The problem is the delivery with the pump. They are looking for safer and better deliveries. GDNF is a neurotrophic factor. The most promising trial with neurotrophic factor at the moment is the ceregene trial. But we still have to wait for good results from them.