Indication: Alzheimer’s disease

Source: New England Journal of Medicine, April 14, 2005 online edition (appeared in June 9th print edition)

Research: As part of the study, re­searchers examined the effect of donepezil (a drug prescribed for mild to moderate stages of Alzheimer’s disease) and vitamin E on delaying diagnosis of Alzheimer’s disease among a subset of people with mild cognitive impairment (MCI) with apolipoprotein E-4 (APOE-4), the only known genetic risk factor for late-onset Alzheimer’s disease. Participants were randomized to three groups, one taking 2000 IU daily of vitamin E, the second receiving 10 mg of donepezil daily, and the third taking a placebo. All participants also took daily multivitamins. The average age of the participants at baseline was 73 years.

Results: Among the 769 study participants enrolled at 69 sites in the U.S. and Canada, 212 developed possible or probable Alzheimer’s disease within the 3-year study period. The overall rate of progression from MCI to Alzheimer’s disease for all three treatment groups combined was 16% per year. The study found that the donepezil group’s risk of progression to a diagnosis of Alz­heimer’s disease was reduced by 58% 1 year into the study, 36% at 2 years, but there was no risk reduction at the end of the full 3 years of the study. Vitamin E was found to have no effect at any time in the study when compared with placebo.