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FOR IMMEDIATE RELEASE
Contact:
Karen Zipern, Columbia University
Medical Center
212-305-9746; kz2110@columbia.edu
NEW STUDY SUGGESTS LEVODOPA MAY SLOW PROGRESSION
OF PARKINSON DISEASE
Columbia University
Medical Center
part of multi-center trial that may resolve controversy over most effective
Parkinson therapy
New York, NY (Dec. 8, 2004) – Levodopa is the most powerful drug available to treat the
symptoms of Parkinson disease, and almost all patients with the disease will
eventually need to take it. But there
has long been controversy about when it should be started, in part because of
concern that the medicine itself might cause further damage to the brain
cells that are impaired in this disease.
To resolve the controversy, a Columbia University
scientist led a team of experts from the Parkinson Study Group to study levodopa’s effect on the rate of progression of the
disease.
The study, reported in the December 9 issue of The New England Journal of Medicine, showed not only that levodopa does not appear to worsen the disease, but that
it may actually slow its progression. A total of 38 Parkinson Study Group
sites across the U.S. and Canada
conducted this multi-center, placebo-controlled, double-blind clinical trial
involving 361 newly diagnosed Parkinson disease patients.
Stanley Fahn, M.D., professor of neurology at Columbia University Medical
Center, was the
principal investigator of the study. “Although there is still uncertainty
on how to interpret the study and further investigation will be necessary to
prove levodopa’s value beyond reasonable
doubt, we found that levodopa did not accelerate
the pace of Parkinson disease,” said Dr. Fahn.
“Now patients can feel more secure about the drug and may wish to start
it sooner rather than later.”
The co-principal investigator, Ira Shoulson, M.D.,
professor of neurology at the University of Rochester, added, “The
results of this study are important because they help provide confidence for
both patients with Parkinson disease and their doctors about the safety of levodopa.” Drs. Fahn and Shoulson advised, however, “The results do not
prove that levodopa slows the underlying nerve
degeneration of Parkinson disease, and a differently designed clinical study
will be necessary to address this concept.” A follow-up study is already in the
planning stages. Drs. Fahn and Shoulson
further cautioned, ”The high dose required for
the best effect produced more undesirable side effects, such as abnormal
involuntary movements, which is another reason patients have delayed starting
levodopa.”
About Parkinson’s Disease
Parkinson’s disease is a progressive neurological disorder that
affects approximately 1.5 million Americans.
The disease is characterized by tremor, stiffness, slowness and
eventually poor balance control. The symptoms are due to loss of nerve cells
in the brain that contain “dopamine.” The most effective
treatment for Parkinson’s is dopamine replacement therapy with the drug
levodopa, which is changed to dopamine in the
brain. Levodopa is commonly sold in combination
with carbidopa under the brand name “Sinemet” or its generic equivalent. Over time, Parkinson disease continues to
worsen, and new symptoms emerge that do not respond as favorably to levodopa therapy.
Because Parkinson’s is a progressive disorder, the symptoms
worsen with time.
About the Study
Research physicians at Columbia
University Medical
Center and 37 other Parkinson Study
Group sites in the United States
and Canada
evaluated 361 newly diagnosed participants with early Parkinson disease. There were four treatment groups: (1) carbidopa/levodopa 12.5/50 mg three times daily; (2) carbidopa/levodopa 25/100 mg three times daily; (3) carbidopa/levodopa 50/200 mg three times daily; and (4)
matching placebo. Neither the study
participants nor the investigators were aware of the treatment assignments.
After 40 weeks (9 months) of treatment, the medications were withdrawn, and 2
weeks later, after allowing the symptomatic benefit of levodopa
to dissipate, the subjects were evaluated to see how far the disease had
worsened since the baseline examination 42 weeks earlier. The placebo-treated
group represented the natural progression of the illness.
The primary outcome of the study was to measure Parkinson impairment between
the beginning of the study (week zero) and the end of the study (week 42). If
levodopa accelerated disease progression, then
those treated with levodopa would be expected to
have more severe impairment than the placebo-treated group after the
symptomatic benefit of levodopa had been eliminated
through the 2-week washout phase. If levodopa
slowed progression, then the levodopa-treated
subjects would be expected to have less severe Parkinson disease than the
placebo-treated group.
The clinical results showed a clear-cut benefit in favor of levodopa. Moreover, the higher the dosage, the more
beneficial the result. A question remains, however, as to whether the 2-week
washout of the drug was sufficient to account for the elimination of all of levodopa’s symptomatic benefit.
The study also contained a brain imaging component that showed the opposite
effect from the clinical research evaluations. Participants underwent
evaluation of their dopamine neurons at the beginning of the study and again
after 40 weeks of treatment. These results suggest that levodopa
could possibly have accelerated the loss of dopamine neurons. These findings
also raise the question as to whether levodopa
treatment interfered with the imaging by temporarily altering the chemistry
of the dopamine neurons.
The PSG
(www.Parkinson-Study-Group.org) is a non-profit, cooperative group of
Parkinson disease experts from medical centers in the United States and Canada who are dedicated to
improving treatment for persons affected by Parkinson disease.
The National Institutes of Health and the Department of Defense’s
Neurotoxin Project provided financial support for this study, known as the
ELLDOPA (Earlier versus Later LevoDOPA Therapy in
Parkinson Disease) Study. Teva Pharmaceuticals
Industries of Netanya, Israel, which markets generic levodopa, provided the supply of levodopa
and matching placebos gratis.
Columbia University Medical Center
provides international leadership in basic, pre-clinical and clinical
research, medical education, and health care. The medical center trains
future leaders in health care and includes the dedicated work of many
physicians, scientists, nurses, dentists, and other health professionals at
the College of Physicians & Surgeons, the School of Dental & Oral
Surgery, the School of Nursing, the Mailman School of Public Health, the
biomedical departments of the Graduate School of Arts and Sciences, and
allied research centers and institutions. With a strong history of some of
the most important discoveries in health care, its researchers are leading
the development of novel therapies and advances to address a wide range of
health conditions.
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