Therapy Type: DNA/RNA-based
Target Type: Amyloid-Related (timeline)
Condition(s): Alzheimer's Disease
U.S. FDA Status: Alzheimer's Disease (Phase 1)
This gene-therapy approach uses a viral vector to drive expression of human apolipoprotein E2 protein (APOE2) in the central nervous system. The serotype rh.10 adeno-associated virus with APOE2 cDNA is surgically injected into the fluid-filled space at the base of the brain.
APOE gene isoforms strongly affect the risk of developing Alzheimer’s disease. APOE4 raises the risk, APOE2 reduces it. APOE4 is associated with acceleration of amyloid accumulation in the brain compared with other isoforms; E2 protects against pathology (e.g., Reiman et al., 2020). The rationale for gene therapy is to increase the expression of E2, and overcome the harmful effects of E4.
In preclinical work, AAVrh.10-APOE2 was tested in mice expressing human APP, PS1, and APOE4. Intracerebral delivery of the virus led to widespread brain expression of APOE2, and decreased Aβ levels and amyloid deposition (Zhao et al., 2016). APOE2 gene therapy reduced amyloid most effectively when given before plaque accumulation began.
Studies using nonhuman primates compared APOE2 expression in brain two months after intraparenchymal, intracisternal, or intraventricular delivery of AAVrh.10-APOE2. Intracisternal delivery was the safest and resulted in widespread brain expression of APOE2 (Rosenberg et al., 2018).
In October 2019, investigators at Weill Medical College of Cornell University began a Phase 1 trial evaluating AAVrh.10-APOE2 in 15 volunteers who carry two APOE4 alleles and have PET- or CSF-confirmed brain amyloid deposition and a clinical diagnosis of mild cognitive impairment to severe dementia. This open-label, dose-ranging study involves a single intracisternal injection of one of three doses of AAVrh.10-APOE2, and a two-year follow-up. Its goals are to establish the maximum tolerable dose and determine if APOE2 protein appears in the cerebrospinal fluid. The primary endpoint is safety and the number of adverse events or serious adverse events. The trial is set to end in December 2021.
For details on this trial, see clinicaltrials.gov.
Last Updated: 31 Jul 2020
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