New drug may slightly help delay onset of Alzheimer's, clinical study suggests

• In a study of people with mild cognitive impairment (MCI), those who took the drug donepezil were at reduced risk of progressing to a diagnosis of Alzheimer's disease (AD) during the first year of the trial, but by the end of the 3-year study there was no benefit from the drug.
• These findings, from the Memory Impairment Study, are the first to suggest than any agent can delay the clinical diagnosis of AD in people with MCI.
• The effects of the drug measured in this study "did not provide support for a clear recommendation for the use of donepezil" generally to forestall the diagnosis of AD in people with MCI, the researchers stated in their report, but they did note the potential importance of the findings for some patients.
• The data, they said, "could prompt a discussion" between clinicians and patients on the possibility of donepezil therapy in certain cases.
• The research was funded in part by the National Institute on Aging (NIA) and was conducted as part of the Alzheimer's Disease Cooperative Study (ADCS), a nationwide clinical trials consortium supported by the NIA, a component of the National Institutes of Health, U.S. Department of Health and Human Services.
• As part of the study, the researchers examined the effect of donepezil and vitamin E on delaying diagnosis of AD among a subset of people with MCI with apolipoprotein E-4 (APOE-e4), the only known genetic risk factor for late-onset AD.
• While the overall rate of progression to AD was greater in this group, use of donepezil in the APOE-e4 subset was beneficial for up to 36 months in reducing the risk of an AD diagnosis.
• "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.