Pramipexole (pramipexole dihydrochloride tablets), earlier approved in the United States for treating the disease in its early stages, was also recommended for the same purpose in Europe. This complies with new guidelines for managing Parkinson’s disease, issued in June 2001.
The new guidelines considered results of a long-term clinical trial with pramipexole, supporting the advantages of starting treatment with it. In controlled clinic trials in Europe and North America covering about 2,100 patients, pramipexole effectively alleviated the signs and symptoms of Parkinson’s disease.
"With pramipexole, a paradigm shift in the initial treatment of Parkinson’s disease has been achieved," said Prof. Werner Poewe, symposium chairman.
About one percent of people over age 60 are affected by PD, which causes tremor, muscle rigidity, slowed motion, shuffling gait and loss of facial expression. About 15 percent of patients develop it before the age of 50.
All of these effects worsen over time. Among the symptoms and signs of Parkinson’s disease which are akinesia, rigidity and tremor, the latter has a major impact on the patients’ quality of life. PD is the second most chronic neurological disorder in older adults, after the Alzheimer’s disease.
Initial therapy with pramipexole in the early stages of Parkinson’s disease significantly delayed motor complications as compared to levodopa. Seventy-two percent of patients given pramipexole as initial therapy remained free from "wearing off" phenomena, "on-off" effects, or dyskinesias after two years, as compared with only 49 percent of patients initiated on levodopa.
In open label studies, pramipexole was shown to successfully manage the symptoms of Parkinson’s disease for up to 4.5 years in a significant number of patients without the need to add levodopa. Pramipexole was the first dopamine agonist to be shown to significantly improve tremor in patients in whom it predominates.
Recently, the Journal of American Medical Association published the results of a study revealing improvements of early Parkinson’s disease treated with pramipexole. Using single photon emission computerized tomography, a specialized camera that measures changes in the brain, investigators found that patients who received initial treatment with pramipexole demonstrated a slower rate of decline in dopaminergic neuronal functioning compared with patients who received initial treatment with levodopa.
This study result is clinically important since patients with Parkinson’s disease have already lost an estimated 50 to 80 percent of their dopaminergic neuronal functioning before symptoms or abnormal signs of function are detected.
"This study adds new and important information to the knowledge in the early treatment of Parkinson’s disease. The outlook for patients suffering from the devastating consequences of Parkinson’s disease has very much improved," said Dr. Alessandro Banchi, a member of the Boehringer Ingelheim board of managing directors.
Pramipexole was jointly developed by Boehringer Ingelheim and Pharmacia Corp. Internationally, it is marketed as Mirapex, Mirapexin or Sifrol. In the United States, it is co-promoted by Boehringer Ingelheim Pharmaceuticals and Pharmacia as Mirapex.
The drug is approved for treating the signs and symptoms of idiopathic Parkinson’s disease, as monotherapy (without levodopa) or in combination with levodopa. The approval applies to treatment over the course of the disease to late stages when the effect of levodopa wears off or becomes inconsistent and fluctuations of the therapeutic effect occur.