Apolipoprotein E epsilon 4 allele predicts a positive response to tacrine in Alzheimer's disease

As a by-product of the French tacrine treatment protocol, we have attempted to correlate the apolipoprotein E (apoE) genotype of patients with Alzheim er's disease (AD) with their response to tacrine to investigate whether gen otype may help to identify positive responders to treatment. The 102 patien ts selected were given tacrine for 6 months with a maximal dose of 160mg/da y at the end of this period. Mini-Mental State Examination (MMSE) score at the start of treatment was at least 10 and 67 patients (66%) herd one or tw o apoE epsilon 4 alleles (epsilon 4(+)). MMSE was measured again after 6 mo nths of treatment. Forty eight epsilon 4(+) patients responded to tacrine t reatment whereas only 12 out of 35 epsilon 4(-) patients showed a response. Differences between the two groups were statistically significant. However no significant differences for sex, age and disease state at baseline were observed. The results suggest that the apoE epsilon 4 status may be respon sible for same degree of tacrine response in mild AD pathology.