For actress Lucy Roucis, every day is a battle for control of her own body. On a good day, she is able to control her muscles for four to five hours at a time. But on bad days, she lies on the floor of her apartment, curled in a tight ball, unable to move until her medications kick in.
The incidence of Parkinson’s disease may be on the rise, but treatment options are also increasing. Although there is still no cure, scientists are developing a number of new medical and surgical treatments to help patients maintain control of their lives.
Understanding the enemy
Parkinson’s disease was first described in 1817 by London physician James Parkinson. Today, nearly two centuries later, the underlying cause of the disease is still a mystery; but scientists know the symptoms occur because patients are unable to produce enough dopamine, a chemical in the brain necessary for normal movement.
“Parkinson’s disease destroys neurons, or brain cells, that produce dopamine,” explained Dr. William Wheeler, chief medical officer of Aderis Pharmaceuticals, which is developing new treatments for Parkinson’s. “The slow progression of this disease is difficult for patients. The symptoms may be deceptively mild in the beginning, maybe just shaky hands, but they invariably worsen as more dopamine-producing neurons are destroyed.”
The destruction of dopamine-producing neurons causes a variety of symptoms related to motor control including tremors, rigidity, uncontrolled muscle movement (called dyskinesia), speech disorders and loss of bladder control. Occasionally, Parkinson’s disease patients also experience emotional symptoms such as depression and dementia.
The Parkinson’s patch
For the past 35 years, Levodopa, commonly referred to as L-Dopa, was considered the gold standard in Parkinson’s treatment.
L-Dopa alleviates the symptoms of Parkinson’s disease by supplementing levels of naturally produced dopamine, but recent studies suggest that long-term use of
L-Dopa may be associated with side effects — including uncontrolled muscle spasms.
In light of this evidence, 85 percent of neurologists now prescribe a mimic — called dopamine agonists — that tricks the brain into thinking the chemical is present, according to the American Parkinson’s Disease Association.
But this treatment also has its limitations.
“Dopamine agonists are an effective treatment, but they are only available in pill form,” Wheeler said. “These pills must be taken several times a day, so the level of medication in the patient’s bloodstream rises when they take the pill, causing side effects, and falls before the next one kicks in, causing Parkinson’s symptoms.”
Maintaining the delicate balance between symptoms and side effects is a full-time job, according to Roucis.
“Drug therapy lets me walk away from this disease temporarily,” she said. “My dilemma is that I don’t want to take more pills too soon because I don’t want to overdose, but if I don’t take them soon enough it takes twice as long for them to kick in.”
A daily skin patch developed by Aderis Pharmaceuticals may help patients like Roucis. Much like a nicotine patch used by smokers, the Parkinson’s patch delivers a steady stream of a novel dopamine agonist over 24 hours, which could potentially lessen the symptoms and side effects caused by dopamine agonist pills. Not yet approved by the Food and Drug Administration, the patch is in its final phase of clinical trials and could be available to patients within two years. The incidence of Parkinson’s disease may be on the rise, but treatment options are also increasing. Although there is still no cure, scientists are developing a number of new medical and surgical treatments to help patients maintain control of their lives.
Gene therapy
According to the National Parkinson’s Foundation, there are currently three types of surgery available for the treatment of Parkinson’s: ablative surgery, in which select areas of the brain are destroyed; deep-brain stimulation, in which electrodes are implanted into the brain; and restorative surgery, in which dopamine-producing cells are implanted in the brain.
“Although there are a variety of surgical options, only about 0.1 percent of patients choose to undergo surgery,” said Wheeler. “Many people are just not good candidates for surgery, and even if they are, the idea of brain surgery can be scary. Also, surgery doesn’t cure Parkinson’s; it just removes some of the troubling symptoms for a while.”
Enter gene therapy, which involves altering genes by either replacing a faulty gene with a functional one or interfering with a gene that is causing problems. Although the concept of altering genes is somewhat controversial, recent gene therapy studies have shown the potential to actually slow down the destruction of dopamine-producing brain cells that cause Parkinson’s disease. Scientists at Thomas Jefferson University’s Medical College in Philadelphia and Cornell University’s Weill Medical College hospital in New York successfully used gene therapy to interfere with the progression of Parkinson’s in rats. They plan to begin testing their approach on humans in early 2003.
“My doctors want me to have brain surgery, but it’s too invasive — they drill holes in your head while you are awake,” said Roucis. “If surgery was a cure, I would do it in a heartbeat, but I know something better will come along. In the meantime, I have wonderful people around me to love and support me. I have a life to live.”