Parkinson's Patch Nears U.S. Approval
Once-a-Day Drug for Parkinson's Disease Safe, Effective in Clinical Trials
Jan. 3, 2007 -- A once-a-day patch is a safe and effective treatment for early Parkinson's disease, a clinical trial shows.
Transdermal rotigotine is the patch's scientific name. Under the brand name Neupro, it's already sold in Europe by manufacturer Schwarz Pharma.
Study leader Ray L. Watts, MD, chairman of the neurology department at the University of Alabama at Birmingham, says that what makes the patch unique is its continuous, steady delivery of an effective Parkinson's drug.
"This was the pivotal clinical trial [of the patch] in North America for early Parkinson's disease," Watts tells WebMD. "It showed that this treatment provided a very good benefit for Parkinson's disease symptoms."
Watts and colleagues report the results of the initial six-month study of the Parkinson's patch in the Jan. 23 issue of the journal Neurology.
The study shows that 48% of people with early Parkinson's disease responded to the drug, vs. 19% who responded to an inactive placebo patch. Overall, patients had significantly improved scores on a test of motor function.
Parkinson's disease is caused by the death of brain cells that make an important chemical messenger called dopamine.
The drug L-dopa is still the gold standard Parkinson's treatment. It works by giving the brain a precursor compound that brain cells turn into dopamine. It works well -- but after about five years, patients have a wearing-off effect at the end of each dose. This effect results in an "on/off" phenomenon when patients suddenly experience erratic, involuntary motions.
Can Parkinson's Patch Outperform Its Peers?
The Parkinson's patch gives patients a kind of drug known as a dopamine agonist. It directly plugs in to dopamine receptors on brain cells. This doesn't work quite as well as dopamine itself -- but because these drugs have a longer half-life than L-dopa, they smooth out the on/off effect. Half-life is the time that it takes for half of the drug to be broken down by the body.
"There have been several pivotal studies that show if you start patients on a dopamine agonist, you get less of these motor complications after five years," Watts says. "The two currently leading dopamine agonists, Mirapex and Requip, are oral drugs that are shown to do that."