Memory Impairment Study

Introduction

Study characteristics:

• randomized trial
• 769 subjects with mild cognitive impairment (MCI) at 69 sites in U.S. & Canada
• average age at baseline = 73
• 3 year study

Treatment:

• donepezil or vitamin E vs placebo

Groups:

• 2000 IU vitamin E QD
• 10 mg donepezil QD
• placebo

All participants also took daily multivitamins

Results:

• 212 developed possible or probable AD within 3-years
• overall rate of progression from MCI to AD for all 3 groups combined was 16% per year (does not correlate with the value of 212)
• risk* of progression to a diagnosis of AD was reduced by 58% in donepezil group at 1 year & 36% at 2 years
• no risk* reduction in donepezil group at 3 years
• no risk* reduction in vitamin E group at 1,2 or 3 years
• subset of subject with apoE4 allele
  • overall rate of progression to AD was greater in this subset
  • risk* reduction in donepezil group at 1,2 & 3 years
• donepezil reduced risk of progressing to Alzheimer's disease (AD) for the first 18 months of a 3-year study compared with placebo
  • donepezil group averaged 661 days until a diagnosis of AD
  • vitamin E group averaged 540 days from MCI to AD
  • placebo averaged 484 days to AD
• reduced risk of progressing from MCI to a diagnosis of AD among participants on donepezil disappeared after 18 months

* risk relative to placebo

This study 'did not provide support for a clear recommendation for the use of donepezil' in people with MCI.

This study 'could prompt a discussion' between physician & patient regarding possible benefit of donepezil in some cases.

No recommendation for apoE4 genotyping for people with MCI.

This study did not answer the question of whether donepezil reduces the underlying brain changes in Alzheimer's disease.

Funded in part by the National Institute on Aging (NIA)

Conducted as part of the Alzheimer's Disease Cooperative Study (ADCS)

primary support from the NIA

additional funding provided by Pfizer, Inc., & Eisai, Inc.

Pfizer & Eisai also contributed the donepezil study medication

vitamin E was provided by DSM Nutritional Products, Inc.

More general terms

• clinical trial