Correction - there were about 75 other monkeys receiving lower doses -
not 5. this sentence should read...
"About 75 monkeys receiving lower doses and those whose
GDNF infusion was not abruptly withdrawn did not develop lesions."
Linda
-- "[log in to unmask]" <[log in to unmask]> wrote:
Hi Claire,
It is difficult to answer this completely because Amgen has still not
released its monkey toxicology data (almost two years after the trial
halt). They have said they are waiting to publish it in a journal
article - which could take yet another year or longer. The company
has not responeded to numerous requests for their monkey toxicology
information from researchers, trial participants and PD
organizations. Not exactly an example of transparency in research.
An article by Todd Sherer of the Michael J Fox
Foundation, "Crossroads in GDNF Therapy for Parkinson's Disease"
appeared in "Movement Disorders vol. 21 no2, 2006, and summarized
previous GDNF studies. This article states that 3 of the five monkeys
that received the highest doses of GDNF for 6 months - 100
ug/putamen/day infused unilaterally and were then withdrawn from
treatment for 3 months showed an "unusual pattern of cerebellar
toxicity." About 5 monkeys receiving lower doses and those whose
GDNF infusion was not abruptly withdrawn did not develop lesions.
The highest dose ever given to a human patient was 42 ug/day in the
Bristol phase 1 study. In the phase II (Amgen study) the dose was 15
ug/putamen/day. TO date there is no evidence of cerebellar damage in
any of the human trial participants.
Yet this promising treatment still sits on the shelf in Amgen's lab -
the biotech company will not test it further and they will not
release their patent to another company or instiution who would
continue the research and go on to a phase III clinical trial.
Linda
For more info see:
http://www.pdpipeline.org/yy_gdnf/gdnf_overview.htm
For learn what has happened to GDNF trial participants see:
http://grassrootsconnection.com/gdnf_profiles2006/participants.htm
-- Claire Salamon <[log in to unmask]> wrote:
Linda Herman, In your July 1, 2006 message ''New GDNF
STUDY"
the sentence reads:
" Pro-GDNF researchers have always believed the lesions
in
a few monkeys were caused by abrupt withdrawal from extremely high
doses
-- much higher than any of the human subjects...."
Do you know the figures on the doses given to the
monkeys?
Each dose and how many doses a day?
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