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New treatment for Parkinson's disease is being tested in clinics
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Copyright 1996 Nando.net
Copyright 1996 San Francisco Examiner

SAN FRANCISCO (Aug 23, 1996 2:23 p.m. EDT) -- Doctors at Parkinson's
disease clinics around the nation last week began injecting into the brains
of patients a protein that specialists say has the potential of
dramatically slowing or even reversing the brain disorder.

It may be several years before the value, if any, of the growth factor
protein, called GDNF, is known. However, specialists in Parkinson's disease
said the product, patented by the California biotechnology company Amgen
Inc., looks like an important find in research into the incurable
degenerative movement disorder.

"I believe that, eventually, treatment with growth factors or neurotrophic
factors (such as GDNF) is going to revolutionize the treatment of disorders
like Parkinson's," said Dr. Michael Aminoff, a UC-San Francisco professor
of neurology who heads a Parkinson's clinic declared a center of excellence
by the National Parkinson's Foundation.

Stock analysts, like scientists, want to see the results of the study
before they pass final judgment on Amgen's discovery. David Crossen of
Montgomery Securities in San Francisco visited the company's facilities
last week and came away persuaded "GDNF is a very important project."
Still, he has a hold on the stock until more is known about GDNF's
effectiveness.

Amgen, a biotechnology company based in Thousand Oaks, Calif., said it has
begun human clinical trials of its product at multiple clinics it would not
identify, lest they be overwhelmed by Parkinson's patients seeking help.

"I have the necessary desperation," Joan Samuelson of Santa Rosa, Calif.,
said of her hopes that GDNF or another therapy could cure the disease she
has had for 10 years. Samuelson heads Parkinson's Action Network, a
national advocacy group.

The experiment, following recent federal approval, will test GDNF's safety
in people with moderate to severe Parkinson's. This phase may take a year.
More lengthy tests would follow if it is found to be safe.

Parkinson's, affecting a million or more Americans, causes muscle tremor,
stiffness and weakness. Its symptoms are trembling, a rigid posture, slow
movements and a shuffling, unbalanced walk. As many as one-third of
Parkinson's patients develop dementia.

The disorder was defined by James Parkinson, a British surgeon. Its victims
suffer damage to nerve cell clusters in the brain called the basal ganglia,
where a nerve transmitter known as dopamine is made.

The most effective drug used for Parkinson's has been Levadopa, or L-dopa,
which the body converts into dopamine, but over the years it loses its
effect and may even be toxic. Scientists are at odds over this claim, but
they agree L-dopa cannot halt the degeneration of brain cells.

Patients typically survive 10 to 15 years after symptoms appear. Many
become so rigid that they die in accidents, such as in falls in which hips
are broken, said Dr. Jeff Bronstein, a neurologist who heads the UCLA
Medical Center Movement Disorder Center. He called Amgen's research "really
spectacular."

The research on humans followed successful results with monkeys.

In 1982, Michael Carrillo, a drug addict, arrived at Santa Clara Valley
Medical Center in Campbell, Calif., nearly paralyzed and unable to speak.
Soon, other addicts -- who came to be known as "the frozen addicts" -- came
for treatment, all with Parkinson's-like symptoms.

They were seen by neurologist Dr. William Langston, who found they had all
taken synthetic heroin that had a byproduct called MPTP, which an enzyme in
the body converts to a poison. In further study, he found the MPTP attacked
the brain cells that produce Parkinson's symptoms when they fail.

Since then, researchers have given monkeys MPTP to produce symptoms similar
to those of Parkinson's.

The Amgen researchers say they were able to protect dopamine neurons from
toxic damage, restore functional activity to dormant dopamine neurons in
monkeys and reverse the symptoms of Parkinson's. It remains to be seen if
they can do the same in people.

"This safety trial gets us to first base, but this a five-or-more-year
program," said Amgen spokesman David Kaye. "This is a tragic disease, and
we do not want to contribute to expectations getting wildly out of hand."

Crossen, the Montgomery Securities analyst, said he learned that 50
patients are in the trial and that GDNF theoretically corrects rigidity,
not the symptomatic tremors.

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