An international team of Parkinson's disease researchers has shown that a potential new drug is effective at treating patients in the early stages of Parkinson's and may even slow the progression of the disease. The results from the Parkinson Study Group are in the April 19 issue of the Archives of Neurology.
The effects of the compound rasagiline were measured in a study of 371 patients with early Parkinson's disease. Using a common method to measure the effects of the disease, researchers with the Parkinson Study Group showed that the drug helps treat many of the symptoms of the disease, allowing people to better carry out such everyday tasks like cutting food, writing, and dressing oneself.
While the improvement in symptoms was in line with that offered by other medications on the market, the drug generally caused fewer side effects than many Parkinson's drugs, researchers say, including less sleepiness and nausea and fewer hallucinations.
In this study the researchers also sought to separate out the short-term and long-term effects of the medication. While physicians can assess the impact of a medication on a patient's symptoms, it's difficult to know whether it is actually slowing the progression of Parkinson's disease, says neurologist Ira Shoulson, M.D., of the University of Rochester, the principal investigator of the study.
"With cancer, for instance, you can look at a tumor and watch what happens – if the tumor shrinks, you know the medication is having an effect on the cause of the patient's symptoms. But we don't have such clear biomarkers for Parkinson's disease, though we're working to develop them."
So the investigators created a unique type of study to address the question. Some people in the "delayed-start study" received the medication for the entire year of the study, while others received it only for the last six months. The investigators found that the people who received rasagaline for only the last six months improved compared with their own performance in first 6 months, but they never reached the level of improvement attained by the people who received rasagiline continuously for the entire 12 months. The result could be a sign that the medication actually helps to protect the brain cells targeted by the disease.