815. Aerosol Delivery of Helper-Dependent Adenoviral Vector into Nonhuman Primate Lungs Results in High Efficiency Pulmonary Transduction with Minimal Toxicity

Abstract

Cystic fibrosis is caused by recessive mutations in a membrane chloride channel gene (CFTR) expressed in the airway epithelium and is characterized by persistent, progressive inflammation and infection, eventually leading to lung failure. A major obstacle to CF gene therapy is inefficient pulmonary transduction by viral and nonviral vectors in large animals and humans. To address this obstacle, we have used a novel strategy for efficient aerosol delivery into nonhuman primate lungs of a helper-dependent adenoviral vector (HDAd) bearing a human airway epithelial cell and submucosal gland cell-specific expression cassette driving LacZ. The AeroProbe, an intracorporeal nebulizing catheter, was used to aerosolize 1.67|[times]|1011 vp/kg of the HDAd formulated in 0.45 ml/kg of 0.1% L-a-lysophosphatidylcholine (LPC) directly into the airways of three baboons at a rate of 0.6 ml/min. Extensive and unprecedented high levels of transduction of the ciliated epithelium of the trachea, bronchi and bronchioles as well as submucosal glands were observed in all three baboons. No respiratory distress was noted for all three animals following vector administration. Chest X-rays revealed no abnormalities at 6, 48 and 72 hours post-administration for two animals. Minimal infiltrate at the site of bronchoscopy was noted in the third animal. Laboratory findings (chemistries, cell counts, cytokines, etc) in the blood and BAL fluid were unremarkable. Histological examination at 72 hours post-administration revealed only mild and patchy subclinical pneumonia in all three animals. This study demonstrates a novel and promising strategy to achieve high efficiency transduction of the trachea, the proximal and distal airway epithelium and submucosal glands in a large animal model for HDAd-mediated, lung-directed gene therapy for CF.