Up and Coming Drugs for Parkinson's
April 18, 2002 -- Three new drugs showing great promise in the treatment of Parkinson's disease are being discussed at this week's annual meeting of the American Academy of Neurology.
One drug seems to improve mental sharpness and reduce hallucinations in late-stage Parkinson's patients, says study author Paul Reading, PhD, of the Regional Neurosciences Centre of Newcastle General Hospital in England.
Significant impairment in thinking and hallucinations are relatively common in advanced Parkinson's, according to Reading. Yet in his study of 12 patients, six weeks of the drug Exelon -- currently used to treat Alzheimer's disease -- showed "significant improvements," he says in a news release. When the 12 quit taking the drug, their symptoms returned.
The drug had added benefits: Patients had faster reaction times, were better able to focus, and had better memory when performing tasks.
"We are encouraged by the fact that these benefits of [Exelon] therapy did not seem to come at the expense of patients' [muscle] control," Reading says.
The Exelon study was supported by the drug's maker, Novartis Pharmaceuticals Corp.
Studies of two drugs to treat early-stage Parkinson's show they both work better than levodopa, the gold standard used for some 30 years. Both drugs seem to work better than levodopa in slowing the loss of brain cells that produce the chemical dopamine.
Mirapex was tested for six weeks against levodopa in 82 patients with early Parkinson's. With Mirapex, patients had from 21% to 25% improvement in thinking abilities. Patients also had fewer hallucinations and sleep disturbances. Overall, loss of dopamine function was slowed by about 40%.
This study was partially sponsored by Pharmacia Corp. and Boehringer Ingelheim, the makers and distributors of Mirapex.
The data suggest that patients initially treated with Mirapex experience a significantly slower rate of loss of dopamine-producing brain cells compared to those treated with levodopa, according to study author Kenneth Marek, MD, with the Institute for Neurodegenerative Disorders in New Haven, Conn.
Requip was similarly tested against levodopa in a two-year study of 93 patients with early Parkinson's, says study author Ray Watts, MD, professor of neurology at Emory University School of Medicine in Atlanta.
In his study, the loss of dopamine function slowed by 30% compared with patients taking levodopa. Involuntary movements, called dyskinesia, also were greatly reduced by Requip.
Watts' study was supported by GlaxoSmithKline, the maker of Requip.
"These findings could certainly mean a better quality of life for a longer period of time in Parkinson's patients," says Watts. Whereas dopamine function might have been lost over 10 years, that time could possibly be stretched to 13 years by starting and maintaining treatment with Requip. "These findings will help guide the treatment of early Parkinson's disease and could be an important factor in changing the treatment methods of Parkinson's."