Research Article A phase1 study of stereotactic gene delivery of AAV2-NGF for Alzheimer's disease

Background: Nerve growth factor (NGF) is an endogenous neurotrophic-factor protein with the potential to restore function and to protect degenerating cholinergic neurons in Alzheimer’s disease (AD), but safe and effective delivery has proved unsuccessful. Methods: Gene transfer, combined with stereotactic surgery, offers a potential means to solve the long-standing delivery obstacles. An open-label clinical trial evaluated the safety and tolerability, and initial efficacy of three ascending doses of the genetically engineered gene-therapy vector adeno-associated virus serotype 2 delivering NGF (AAV2-NGF [CERE-110]). Ten subjects with AD received bilateral AAV2-NGF stereotactically into the nucleus basalis of Meynert. Results: AAV2-NGF was safe and well-tolerated for 2 years. Positron emission tomographic imaging and neuropsychological testing showed no evidence of accelerated decline. Brain autopsy tissue confirmed long-term, targeted, gene-mediated NGF expression and bioactivity. Conclusions: This trial provides important evidence that bilateral stereotactic administration of AAV2-NGF to the nucleus basalis of Meynert is feasible, well-tolerated, and able to produce longterm, biologically active NGF expression, supporting the initiation of an ongoing multicenter, double-blind, sham-surgery-controlled trial. 2013 The Alzheimer’s Association. All rights reserved.