This ongoing phase 1/2 open-label study (NCT03634007) aims to employ intrathecal administration of serotype AAVrh.10 gene transfer vector expressing the cDNA encoding human apolipoprotein E2 (APOE2) to evaluate the therapeutic efficacy of this intervention in individuals with AD who are homozygous for APOE4. Here, APOE is linked to Alzheimer disease.