Improvement of Motor Function in Early Parkinson's Disease
Improvement of Motor Function in early Parkinson’s Disease by the drug Safinamide
What is the problem and what is known about it so far?
Parkinson’s disease (PD) is a brain disorder that affects about 1.5 million individuals in the United States, with 60,000 new people diagnosed each year. It affects men and women in equal numbers, and while PD usually occurs after the age of 65, one in seven of those diagnosed are under the age of 50. Common signs and symptoms of PD are tremor (shaking), rigidity (stiffness), slowed movement, and changes in posture. These and other symptoms are caused by a lack of dopamine, an important chemical in the brain. PD can be treated with a variety of medications which ease symptoms and slow the progression of the disease. Research efforts are focusing on developing more such medications and therapies with the ultimate goal of stopping or even reversing the progression of the disorder.
Why did the researchers do this particular study?
The investigators wanted to find out if the experimental drug safinamide could improve symptoms in patients with moderately severe PD. Safinamide is believed to increase the amount of available dopamine in the brain. Safinamide is also believed to decrease the amount of glutamate, another important chemical in the brain that is harmful at high levels and may be overproduced in people with Parkinson’s disease.
Who was studied?
168 men and women, aged 30 to 72, with PD for 5 years or less. Patients not on any medications for PD were eligible for the study, as well as patients who were on one PD medication (any of several that act like dopamine) for at least 4 weeks.
How was the study done?
The researchers treated the patients for a total of 12 weeks. The 168 patients were randomly assigned to one of 3 treatment groups consisting of 56 patients each. One group received a placebo pill (not known to be active), a different group received safinamide at a dose of 0.5 mg/kg/day, and the final group received safinamide at a dose of 1.0 mg/kg/day. The patients did not know which treatment they were receiving during the study.
What did the researchers find?
The researchers found that patients who received safinamide at a dose of 1.0 mg/kg/day had the greatest improvement in motor function compared to those patients who received only 0.5 mg/kg/day or a placebo pill. In addition, the researchers found that patients who were already on one PD medication (that acted like dopamine) gained additional improvement in their symptoms when also taking safinamide. Reported side effects were similar among the three groups indicating that safinamide is safe and well tolerated at least over a twelve week period.
What were the limitations of the study?
Because PD is a chronic disorder, PD medications are generally taken for long periods of time. Thus, a longer study would be helpful to show if safinamide remains equally safe and effective past 12 weeks. This study did not include patients with early or advanced PD, so it is impossible to know if these patients would benefit from safinamide. Also, the paper does not state if men and women were equally represented. Finally, it is worth noting that the researchers were supported by Newron Pharmaceuticals, the company developing safinamide.
What are the implications of the study?
This study suggests that safinamide at doses of 1.0 mg/kg/day is well tolerated (at least for 12 weeks) and may be a helpful new treatment by itself or when used with other PD medications (specifically that act like dopamine) for patients with moderately severe PD.
Improvement of Motor Function in early Parkinson’s Disease by the drug Safinamide
Summarized by Kurt H. Kelley, College of Medicine, University of Vermont
Summarized from "Improvement of Motor Function in early Parkinson Disease by Safinamide." Stocchi, F. et al. Neurology, Aug 2004, Volume 63, Number 4, pages 746-748.
