An experimental treatment for Parkinson’s disease reduced by nearly two hours on average patients’ “off-time” – the period each day when medication fails to control slowness and shaking. The results are from a double-blind, phase III clinical trial that compared Abbott Lab’s levodopa-carbidopa intestinal gel against the same medication in pill form in patients with advanced disease.
The University of Alabama at Birmingham was among the sites for the study, and David G. Standaert, M.D., Ph.D., chair of the UAB Department of Neurology, among its authors. The data will be presented by C. Warren Olanow, M.D., professor of neurology at the Mount Sinai School of Medicine and lead author, at the annual meeting of the American Academy of Neurology to be held April 25, 2012, in New Orleans.
Parkinson's disease results from the loss of brain cells that make dopamine, which helps to control movement. As dopamine levels fall, patients experience tremors, muscle stiffness and loss of balance. A commonly prescribed treatment, the levodopa-carbidopa combination works because the body converts levodopa into dopamine and carbidopa escorts levodopa to the right part of the brain. The problem is the treatment wears off, leaving patients to face hours of uncontrollable, debilitating slowness, freezing and tremors each day.
One reason for the break in treatment coverage is that it comes in a pill, and pills sit in the stomach for up to six hours waiting for it to empty into the small intestines. It is only there that levodopa encounters the proteins capable of transporting it into the bloodstream en route to the brain. Thus, researchers envisioned a system that avoids the stomach to steadily deliver levodopa gel directly into the small intestine through a surgically placed tube, and with the help of a pump worn on the belt.
“The results are very exciting, considering that other recently approved drugs on the market reduce off-time by, at most, just over an hour,” said Standaert. “In the study, the gel treatment helped patients who had run out of alternatives with current medications. We believe it may be an important new option for patients with severe Parkinson’s, with benefits comparable to more invasive techniques like deep brain stimulation.”
Patients using the gel system saw an average reduction in daily off-time of 1.91 hours, and an increase in “on-time” without troublesome dyskinesia of 1.86 hours compared with the pill form. Nearly all subjects experienced at least one side effect, although most were short-lived and moderate.
This study was sponsored by Abbott, with Standaert and other authors receiving compensation from Abbott for serving as consultants.