By Maria Bishop
BOSTON, MA -- May 7, 2007 -- Istradefylline, a novel adenosine A2A receptor antagonist, appears to reduce the wearing-off time associated with levodopa and other anti-Parkinson's medications when administered at 20 mg/day to Parkinson's patients, according to results of a multicenter, phase 3, double-blind, efficacy study.
A reduction of "off" time means improved motor function for patients experiencing motor complications, said the researcher who reported these findings here at the American Academy of Neurology (AAN) 59th Annual Meeting.
Joel M. Trugman, MD, associate professor of neurology, department of neurology, University of Virginia, Charlottesville, Virginia, led the study, in which 115 patients randomly received istradefylline 20 mg/day while 115 received matched placebo. All patients were taking stable doses of levodopa; other anti-Parkinson's medications were also in use, to varying degrees.
Nearly 90% of patients in each group completed the 12-week study.
At the endpoint, the change from baseline in the percentage of awake time per day spent in the "off" state was -9.49% for istradefylline and -4.92% for placebo. The difference between the groups was significant (4.57%; P =.025), and translates to an average of 44 minutes less in "off" time for the treatment group.
Similar frequencies were seen in each group of treatment-emergent adverse events, serious adverse events, and discontinuation due to adverse events. Safety was assessed by reporting adverse events and monitoring of vital signs, weight, laboratory tests, electrocardiogram, and clinical examinations.
The authors noted that dyskinesia was more frequent (+9.4%) in the istradefylline group than in the placebo group.
This study was supported by Kyowa Pharmaceutical Inc.
[Presentation title: Primary Efficacy and Safety of Istradefylline (KW-6002) in Levodopa-Treated Parkinsons Disease Patients With Motor Response Complications: Results of the KW-6002-US-013 Study. Abstract P06.023]
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