Parkinson's Patch Nears U.S. Approval
Once-a-Day Drug for Parkinson's Disease Safe, Effective in Clinical Trials
WebMD News Archive
Jan. 3, 2007 -- A once-a-day patch is a safe and effective treatment for
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
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
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."
Unfortunately, patients on these drugs may begin to experience the on/off
effect as well. It's been thought that this happens because oral medicines
can't deliver a steady stream of the drug to the brain.
The Parkinson's patch is designed to solve this problem. It bypasses the
digestive system and gives a steady supply of the drug to the brain.
"From a potency standpoint, no, this compound is no more potent than
other agonists," Watts says. "But this delivery system is unique.
Studies in animals show long-acting delivery over short-acting delivery reduces
disease symptoms. This long-acting delivery system will be very
important, but the longer-term studies have not yet been done."