New Form of Drug Helping Some Patients with Parkinson's
For more than 40
years, a drug called levodopa has been the most effective treatment for the uncontrolled
movements associated with Parkinson’s disease. Many Parkinson’s patients have
taken a pill form of the medicine – also known as L-dopa – for years to control
their motor fluctuations.
But the pills can lose
effectiveness over time, greatly reducing their value for people in the later
stages of the disease.
However, there’s a
new form of the drug that is making a positive difference for some Parkinson’s
patients. Called Duopa, it is delivered continuously by a pump system instead
“This takes care of
the fluctuations in the movement symptoms that advanced Parkinson’s patients
experience on a daily basis, and they don’t have to rely on pills while the
pump is on,” said movement disorders specialist Dr. Mustafa Saad Siddiqui, an
associate professor of neurology at Wake Forest Baptist Medical Center in
Winston-Salem, North Carolina. “It can mean a very significant improvement in
the quality of life of these patients.”
Parkinson’s disease is
a degenerative disorder of the brain cells called neurons that produce
dopamine, a chemical that helps people control body movements. While tremors are
the best-known sign of Parkinson's, it also commonly causes muscle rigidity and
slowing of movement. There is no cure for the disease, which afflicts
approximately a million people in the United States, including actor Michael J.
Fox and boxing legend Muhammad Ali.
The levodopa in pills
is absorbed in the blood from the small intestine and travels through the bloodstream
to the brain, where it is converted into dopamine and stored in neurons.
In the initial stages
of Parkinson’s, the brain still has some neurons capable of producing and
storing dopamine. The levodopa pills – which usually contain a drug called
carbidopa to reduce nausea and other side effects – give the brain a boost to
ensure a sufficient supply of dopamine, thus promoting normal motor control.
But during the
disease’s more advanced stages, there aren’t enough neurons left to produce or
store enough dopamine. As a result, patients must take more and more levodopa pills
in order to supply the brain with adequate levels. At the same time, Parkinson’s
causes stomach functions to become slow and unpredictable, which can delay or
even prevent the medicine in the pills from leaving the stomach and reaching the
bloodstream in the small intestine. Consequently, later-stage Parkinson’s patients
are subject to more frequent and more pronounced motor fluctuations.
Duopa has proven capable
of addressing those problems.
A gel form of
levodopa and carbidopa developed by AbbVie Inc. of North Chicago, Illinois,
Duopa is delivered by an external pump directly
into the small intestine through a surgically placed tube. The Parkinson’s
patient wears a small pouch that holds the pump and a drug cartridge, and the
Duopa is delivered continuously at a consistent level for up to 16 hours
according to a schedule programmed into the pump.
Siddiqui said he monitored
the efficacy of the drug and delivery system in Europe, where it has been in
use under the name Duodopa since 2004. He directed the clinical trial of Duopa
at Wake Forest Baptist that was part of the multi-center study which led to its
approval by the federal Food and Drug Administration in January 2015.
Two advocates of
Duopa are Parkinson’s patient George Connors and his wife, Kay, of Randleman,
Among the first
participants in the clinical trial at Wake Forest Baptist, he has been taking
Duopa for more than five years now.
“It’s been a
lifesaver,” his wife said. “It has made it easier for him to get up and do
Connors said the
unreliable action of levodopa pills made it difficult for her husband to pursue
activities he loved. But with Duopa, she said, “he goes fishing, mows the yard
and does outside work,” all without having to remember when to take the pills.
George Connors gave
one example of how Duopa works better for him than pills. He said it used to
take him as much as an hour each morning to stand up properly because his toes
would cramp overnight and the levodopa pills were slow to work. With the Duopa pump
system, he said, his toe cramps are gone within minutes.
Siddiqui said that new
drugs and new delivery methods for existing drugs can relieve many of the symptoms
experienced by people with Parkinson’s and that ongoing research holds hope for
“Out of all the
neurological diseases, we are finding Parkinson’s to have more and more
treatments available,” he said.