New Drug Helps Parkinson's Patients
Rasagiline still awaiting approval in United States
FRIDAY, March 11, 2005 (HealthDay News) -- Giving patients being treated with levodopa for late-stage Parkinson's disease a second drug called rasagiline can improve their physical performance, a multinational study finds.
The study of nearly 700 Parkinson's patients in Israel, Argentina and Europe found that adding rasagiline to the drug regimen reduced the time they had poor or absent muscle function by more than an hour a day, said the report in the March 12 issue of The Lancet.
Parkinson's disease causes a steady loss of brain cells that produce dopamine, a molecule essential to motor function. Misfiring brain cells cause tremor, rigidity, loss of balance and other disabling symptoms. Another drug, levodopa, can help make up for the body's lack of dopamine, but its effect starts to wear off with time.
Several drugs are now used to bolster the activity of levodopa. The newly reported trial found that rasagiline was as effective as one of those drugs, entacapone, and that it did not cause significant side effects.
"This study has shown that rasagiline is an effective, safe and simple treatment for Parkinson's disease when used in combination with levodopa," according to a statement by study author Dr. Olivier Rascol, a pharmacologist at University Hospital in Toulouse, France. "Rasagiline achieved the two main goals of treatment after levodopa -- reduced disability and decreased motor fluctuations. These properties position the drug as a favorable candidate to add to the treatment of Parkinson's disease."
Previous studies have shown that rasagiline helps patients in the early stages of Parkinson's disease, noted Dr. Carl E. Clarke, a reader in clinical neurology at the University of Birmingham in England who wrote an accompanying editorial.
"Rasagiline is an effective treatment for the later stages of Parkinson's disease, according to this trial," Clarke said. "It also shows that rasagiline works even when the patient is already receiving a dopamine agonist drug, so combination therapy with these agents is effective."
In addition, the study included an analysis showing that rasagiline is effective and safe for older patients, Clarke said. "Most trials in the past have not done this."
Rasagiline has just been approved for use in Europe, both as one-drug therapy when the disease is first diagnosed and as add-on therapy with levodopa for more advanced cases. The U.S. Food and Drug Administration last year issued an "approvable letter" for the drug -- usually a precursor to full approval -- but final approval for widespread use is still pending.
The delay is not out of the ordinary, said Dr. Karl Kieburtz, a professor of neurology at the University of Rochester Medical Center, who has done studies of rasagiline. "There usually is a period of negotiation between the FDA and the company," he said. "If it didn't come on the market this year, I wouldn't be surprised."
When and if the drug is approved, it probably will be popular because it is easy to use, Kieburtz added. "It can be given once a day and doesn't require titration [careful measurement of dosage], so it does have advantages," he said.
And there is a hope that rasagiline can do what no other Parkinson's medication now does -- slow or stop the progression of the disease. A study Kieburtz reported last year found that people who began the drug earlier did better than those for whom treatment was delayed by six months.
The newly reported study was not designed to test those early findings, Clarke said. "We need a further trial to confirm this," he said.
All you need to know about Parkinson's disease is available from the National Library of Medicine.