New Parkinson's Drug Saves Brain Cells
April 2, 2002 -- The gold standard in Parkinson's disease treatment is facing a tough challenge from a relative newcomer, and millions of people with the disease may benefit from the competition. A new study shows Mirapex slows the loss of brain cells associated with Parkinson's better than levodopa. It's the first time researchers have been able to compare the drugs by looking directly at their effects on the brain, using new brain imaging technology.
Levodopa was originally introduced in the 1960s and has been the standard of care in treating Parkinson's disease (PD) ever since. It eases the symptoms of PD by helping the body replenish its supply of dopamine lost from the disease.
Dopamine is a chemical in the brain that transmits messages between nerve cells that control movement. Previous studies show Parkinson's patients have lost 40-60% of their dopamine brain cells when they begin to show symptoms of the disease.
Mirapex was introduced in 1997 and works by mimicking the role of dopamine in the brain. It's often used in combination with levodopa to help patients regain muscle control.
In the study, which appears in the April 3 issue of The Journal of the American Medical Association, researchers compared the effects of the two drugs using a new type of brain imaging called single-photon emission computed tomography (SPECT). They found patients treated with Mirapex had less loss of dopamine nerve cells than those treated with levodopa.
After 46 months of treatment, Mirapex patients showed an average 16% loss of dopamine nerve cells while those on levodopa had lost about 25%. Mirapex seemed to work better over the long term in fighting brain-cell loss and slowing the development of symptoms. But levodopa was better at easing the signs and symptoms of PD at the start of treatment.
The researchers say their study marks an important first step in comparing therapies for Parkinson's.
Until now, studies that test the effects of Parkinson's disease treatments have been unable to show whether the treatments were merely easing symptoms or actually targeting the disease process itself. By using this type of imaging to look directly at the patient's brain, researchers can now measure brain degeneration.