Effect of ApoE genotype on response to donepezil in patients with Alzheimer's disease.

BACKGROUND/AIMS: The possible influence of apolipoprotein E (ApoE) genotype on the response to acetylcholinesterase inhibitor therapy in patients with Alzheimer's disease (AD) remains a matter of controversy. In order to address this issue, we investigated the effects of ApoE genotype on the clinical response to donepezil in patients with mild to moderate AD. METHODS: An open study was carried out in 51 patients with probable AD who were treated with 5-10 mg of donepezil per day for 48 weeks. RESULTS: Eighteen (35.3%) of the 51 patients had 1 or 2 ApoE epsilon4 alleles. ApoE epsilon4 carriers with AD showed a mean 1.1-point increase from the baseline score of 23.9 on the 70-point Alzheimer's Disease Assessment Scale-Cognitive Component at 48 weeks, while the ApoE epsilon4 noncarrier group showed a 3.1-point increase from the baseline score of 22.5 (p = 0.03). The ApoE epsilon4 carrier group exhibited a mean 0.13-point worsening from the baseline score of 0.97 on the Korean Instrumental Activities of Daily Living at 48 weeks, while the ApoE epsilon4 noncarrier group exhibited a 0.17-point worsening from the baseline score of 0.64 (p = 0.05). CONCLUSION: AD patients who carry the ApoE epsilon4 allele may respond more favorably to donepezil than epsilon4 noncarriers.