ROCKVILLE, Md., June 28 — The FDA has given Exelon (rivastigmine), already approved for treatment of mild-to-moderate Alzheimer's dementia, the added indication of mild-to-moderate Parkinson's dementia.
Exelon, marketed by Novartis, became the first agent approved for the Parkinson's condition.
Steven Galson, M.D., director of the FDA's Center for Drug Evaluation and Research, said dementia associated with Parkinson's disease differs from Alzheimer's dementia. The most common features of Parkinson's dementia are dysexecutive syndrome and impairment of visuospatial functions.
According to the FDA, 0.2% to 0.5% of those 65 or older are affected by Parkinson's dementia. "Until now, there has been no treatment that has been shown to be effective specifically for the dementia associated with Parkinson's Disease," Dr. Gilson said.
The FDA based its decision on results of a randomized, placebo-controlled clinical study with 541 patients who showed symptoms of mild-to-moderate dementia two years or later after their Parkinson's diagnosis. At the end of the 24-week trial, the condition of the Exelon-treated patients, as shown on a scale that measures mental processes, was significantly better than the condition of the patients taking placebo.
The use of Exelon has been associated with significant gastrointestinal adverse reactions. In clinical trials, 47% of the patients treated with the drug developed nausea, and 26% of women and 18% of men taking high doses of Exelon had significant weight loss. Other common adverse events include vomiting, anorexia, dyspepsia and asthenia. In some patients with Parkinson's, treatment with Exelon was associated with a worsening of tremor.