The last time I visited my neuro he was optimistic about the future, but not GDNF in particular. He felt that the research on something called gangliocides was much more promising than GDNF. I did a web search on this and, if I remember correctly, these are related to neurological stem cells which can regenerate neurons of any desired type. The research is in the very early stages as it is for GDNF. Both of these are encouraging because the idea is to regenerate neurons thereby reversing the progression of the disease - not just stopping them or slowing the decline. I know this doesn't answer your original question, but I hope it provides some encouragement. Ron Reiner ([log in to unmask]) 48 + 1yr