Down Syndrome patients may soon have a new treatment option.
A study is underway at the Medical Center to determine if the drug donepezil can be used to treat Down Syndrome patients. Donepezil, manufactured as Aricept by Phizer Inc., is the most widely used drug in the treatment of Alzheimer's disease.
Patients of both diseases show a lack of the enzyme acetylcholine in the brain and are unable to perform daily living skills. Down Syndrome, however, is the result of an extra chromosome 21 at birth while Alzheimer's, whose origin is unclear, develops later in life.
Many Down Syndrome patients develop Alzheimer's by their forties, a contrast to the average onset age in the general population-about 65. Researchers are using Aricept in the study because it blocks the breakdown of acetylcholine, and therefore has the potential of aiding both Down Syndrome and Alzheimer's patients.
"The preliminary data looks promising," said Dr. Priya Kishnani, a pediatric geneticist and coordinator of the study, "but I don't want families to run out and ask for this medication.... We need more studies. I want to make that clear."
The current "double blind" study-in which neither patients nor doctors are aware of who is receiving the drug-is just beginning. Thus far, 20 Down Syndrome-afflicted adults between 18-35 years old have been recruited. Some of the study patients will be given Aricept while the others will be given a placebo drug.
"If shown to be effective in double blind studies, [Aricept] may have modest effects in helping cognition in these patients," said Dr. Ranga Krishnan, chair of psychiatry and a researcher in the study.
The same researchers conducted a preliminary study published March 27 in Lancet. It showed Aricept could possibly improve cognitive and adaptive function in Down Syndrome patients, as indicated by the effects on four adult Down Syndrome patients.
Of the four adults in the original study, two had already begun to show the clinical development of Alzheimer's disease. The four patients were randomly chosen, and all showed some improvement in adaptive and cognitive functioning during the 26-week treatment.
One patient has continued with the drug because of funding received on "compassionate grounds" due to his older age and "because it showed clinical benefits for him, " Kishnani said.
Scientists studying developmental disorders outside of the Medical Center expressed interest in the potential of the study.
"If the findings hold up in controlled clinical trials, it would advance our understanding of the Alzheimer features of Down Syndrome and provide a treatment to ameliorate the cognitive decline noted in this population," said Dr. Helen Tager-Flusberg, director of the Center for Research on Developmental Disorders at the Eunice Kennedy Shriver Center in Washington, D.C.
Dr. Lewis Leavitt, a professor at the Waisman Center for Human Development and Developmental Disabilities at the University of Wisconsin-Madison, said, "should we shower the Duke researchers with praise and affection and wish them well in their further research-definitely." But he urged that it could be a " 'flash in the pan'... that's why further study/evaluation is needed."
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