Study: Aricept Delays Alzheimers, But Not Vitamin E (Reuters)

WASHINGTON (Reuters) - Aricept, a drug long used to treat Alzheimer's disease, can delay its onset a bit but does not prevent it, U.S. researchers said on Wednesday.

And vitamin E has no effect, they reported in the New England Journal of Medicine.

"These findings, from the Memory Impairment Study, are the first to suggest than any agent can delay the clinical diagnosis of Alzheimer's Disease in people with mild cognitive impairment," the National Institute on Aging, which helped pay for the study, said in a statement.

Aricept, known generically as donepezil, is made by Pfizer and Japan's Eisai Co. Ltd. and also generically by India's Ranbaxy Laboratories Ltd. .

"These findings give me a great deal of hope," said Dr. Ronald Petersen of the Mayo Clinic in Rochester, Minnesota, who led the study.

"We have not answered the question of whether donepezil reduces the underlying brain changes in Alzheimer's disease, but now we know that for some people, drug therapy did make a real, clinical difference. I think there will be real opportunities in the future to test other therapies for patients with mild cognitive impairment."

For their study, Petersen and colleagues enrolled 769 people with an average age of 73 and mild cognitive impairment -- which can progress to the severe memory loss that marks Alzheimer's.

They gave them daily doses of vitamin E or donepezil or a placebo for three years.

After three years, 212 of the volunteers were diagnosed with possible or probable Alzheimer's disease.

"Vitamin E had no benefit in patients with mild cognitive impairment," the researchers wrote.

"Although after three years, the rate of progression to Alzheimer's disease was not lower among patients treated with donepezil than among those given placebo, donepezil therapy was associated with a lower rate of progression to Alzheimer's disease during the first 12 months of treatment."

Neil Buckholtz, a dementia expert at the Institute, said, "While the delay in progressing to Alzheimer's disease had a limited effect in this case, it comes at an early stage of memory loss, a critically important time for patients and families hoping that the disease can be held at bay."

As expected, people with a genetic variant called apolipoprotein E-4 were more likely to get Alzheimer's, but they also benefited the most from donepezil, the researchers said.

But they said it was too soon to recommend general testing for the APOE-4 gene, and too soon to recommend widespread use of donepezil in patients with mild memory loss.