Our study corroborates the assertion that APOE is a major, but not exclusive, pathogenic determinant of the pharmacogenetic outcome in AD and that APOE-4 carriers are at biological disadvantage with respect to patients harboring the APOE-3 allele, as previously documented [2,4,6,18,34,35,36,37,49,50,51]. This evidence concerns the gene APOE and Alzheimer disease.