July 19, 2004 (Philadelphia) -- The drug Aricept can hold off Alzheimer's disease for nearly a year and a half, but after that time the drug's effects begin to wear off, say experts at an Alzheimer's meeting.
Eventually, memory and brain functions begin to slip to the point of Alzheimer's disease, says Ronald Petersen, MD, PhD. Moreover, vitamin E has no beneficial effect. Petersen led a multicenter study to determine if Aricept or high-dose vitamin E could prevent mild cognitive impairment, a condition considered to be a precursor to Alzheimer's disease.
The Alzheimer's Association estimates that 4.5 million Americans have Alzheimer's disease, a degenerative brain disease that slowly wipes out memory and eventually leads to dementia. The risk increases after age 65 and numbers continue to go up each year as the population ages.
Marcelle Morrison-Bogorad, PhD, the National Institute on Aging associate director for the Neuroscience and Neuropsychology of Aging Program, says that researchers find themselves in a race against time with many predicting an "epidemic" of Alzheimer's disease by 2050 when an estimated 13.2 million older Americans are likely to have the Alzheimer's disease.
Excitement About Early Treatment
There has been a great deal of excitement about the potential for early treatment aimed at stopping -- or at least slowing -- the deadly progression of the disease. But, Petersen's results, announced Sunday at the 9th International Conference on Alzheimer's Disease and Related Disorders show that the "right" early treatment has not yet been found.
Researchers theorized that Aricept, one of a class of drugs called cholinesterase inhibitors, would be a good choice since it helps increase levels of a brain chemical involved in memory. Likewise, researchers say that cell damage from oxidative stress, which is known to increase with age, may also contribute to Alzheimer's disease. This makes vitamin E, a potent antioxidant, another attractive candidate for early treatment.
The new study involved 769 volunteers with mild cognitive impairment, meaning that they had "memory problems but they were still able to think clearly and to perform tasks such as balancing a checkbook or preparing a meal," Petersen tells WebMD. In the three-year study, about a third of the participants each received 10 milligrams of Aricept daily, 2,000 IU of vitamin E daily, or a placebo. All volunteers were also given a daily multivitamin. The study also involved a family member or close friend to help assess the patient's condition including memory and functional ability, says Petersen.
The study was partially funded by Aricept's manufacturer, Pfizer. The company is also a WebMD sponsor.
Aricept Slows Progression, Doesn't Stop It
After three years, there was no difference in progression to dementia among the three groups, although "the majority of patients in all groups still did not have dementia," says Peterson.
But when the researchers compared data at each of the six-month checkups, they discovered that volunteers in the Aricept group were less likely to show signs of dementia at the 6-, 12-, and 18-month visits than were volunteers in the placebo or vitamin E groups.
But during the second 18 months, the Aricept group caught up, Peterson says.
Asked if the results of the study will influence his clinical practice, Petersen says it is too early to make any recommendations about Aricept but "the information about vitamin E all appears to be going in the wrong direction."
Last month a study in The Lancet reported that while Aricept does improve function on some tests of memory and function, it doesn't have a measurable impact on symptoms nor does it reduce the likelihood that Alzheimer's disease patients will need nursing home care.
William Thies, PhD, vice president for medical and scientific affairs at the Chicago-based Alzheimer's Association, tells WebMD he doubts these findings will have a chilling effect on the use of Aricept for treating Alzheimer's disease patients. He says the Petersen study "confirms what we've already known. The drug does appear to control symptoms for a time but does not stop the disease progression."
As he explains it, "a family member will look at the drug and decide that [the drug] may give six more months with a mother or father or spouse. That is significant for those families."