NEWS: Istradefylline (KW-6002) Reduces Advanced Parkinson's Disease Symptoms

[Murray Charters <mcharters@xxxxxxxxxxxxxx>]

Doctor's Guide, NY
Istradefylline (KW-6002) Reduces Advanced Parkinson's Disease Symptoms

TAMPA, FL -- August 12, 2003 -- After 40 years of treating Parkinson's disease 
with dopamine medications, a new study
shows potential for a non-dopamine drug that may provide benefit for patients 
with advanced Parkinson's disease.

Robert A. Hauser, M.D., first author of the study and director of the 
Parkinson's Disease and Movement Disorders Center
at the University of South Florida, and other researchers across the United 
States, found istradefylline (KW-6002)
reduced by 1.7 hours per day the time that advanced Parkinson's disease 
patients experienced tremors, slowness and
stiffness. Istradefylline did not worsen the severity of dyskinesias and was 
generally well tolerated by participants.

The study, sponsored by Kyowa Pharmaceuticals, Inc., appears in the August 13, 
2003, issue of the journal Neurology.

Patients with Parkinson's disease have less control over motor function and 
experience worsening tremors, slowness and
stiffness as the disease advances. Current dopamine replacement therapy 
improves those symptoms, but after several
years the treatment becomes complicated by a shortened duration of benefit and 
the emergence of twisting, turning
movements called dyskinesias. Once this occurs, increasing dopamine medication 
worsens dyskinesias and reducing
dopamine medication allows a worsening of slowness, stiffness, and tremors.

"Once patients with Parkinson's disease develop both motor fluctuations and 
dyskinesias, it is very difficult to
provide further benefit with dopamine medications," said Dr. Hauser. "This 
study opens the door to the possibility of
providing additional benefit for advanced Parkinson's disease patients and 
confirms the idea that medications that
affect neurotransmitters other than dopamine can provide benefit in Parkinson's 
disease."

In this 12-week, double-blind, placebo-controlled study, 83 patients with motor 
fluctuations and dyskinesias on
levodopa (a dopamine medication) were randomized to three groups. All 
participants continued their levodopa treatment.
One group additionally received placebo, another up to 20 mg per day of 
istradefylline, and the last up to 40 mg per
day of istradefylline. Participants noted their status--whether they were 
asleep, OFF (medication benefit having worn
off), ON (medication providing benefit) without dyskinesia or ON with 
dyskinesia--during half-hour intervals three
times a week on home diaries.

Earlier studies in animal models of PD showed istradefylline exerts an 
antiparkinsonian effect without worsening
dyskinesia. Istradefylline, an adenosine A2A receptor antagonist, changes the 
firing of neurons in a way that improves
motor function in Parkinson's disease.

"More work is needed," Dr. Hauser said. "We may be able to reduce the time 
patients are OFF with slowness, stiffness,
and tremors without worsening the severity of dyskinesias. With dopamine 
medications alone, this is difficult to do."

Other investigators for this study were Jean P. Hubble, MD, of the Ohio State 
University Department of Neurology,
Columbus, OH; Daniel D. Truong, MD, of the Parkinson's and Movement Disorder 
Institute, Fountain Valley, CA; and the
Istradefylline US-001 Study Group.

Drs. Hauser and Hubble received compensation from Kyowa for consultation 
related to the design and implementation of
future studies.

SOURCE: USF Parkinson's Disease and Movement Disorders Center

SOURCE: Doctor's Guide, NY


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