Phase I clinical trials of CFTR gene transfer have been limited by transient expression and inflammatory reactions to adenoviral vectors used previously. Our group has developed an alternative vector system based on adeno-associated virus (AAV), a non-pathogenic human parvovirus. In order to determine the safety and biological activity of AAV-CFTR in humans, a phase I trial of AAV-CFTR delivery to the nasal and bronchial epithelium was performed. In a single-dose, dose-escalation design, 6 cohorts of 2 CF patients each are receiving doses of AAV-CFTR to one side of the nose and to the right lower lobe of the lung by fiberoptic bronchoscopy. The nasal study is blinded, with a placebo solution administered to the opposite side. Nasal doses range from 30 to 1000 replication units (r.u.)(3×107 to 1×109 total particles), while bronchial doses range from 30 to 10000 r.u. Safety assays include clinical scores, PFTs, bronchoalveolar fluid analysis, radiography, and shedding studies. Biological activity assays are primarily in the nose, including whole cell current-patch clamp analysis of CFTR channel function on isolated cells, as well as polymerase chain reaction(PCR), Southern blot of rescued vector sequences, RT-PCR, and nasal potential difference. A total of twelve subjects ranging in age from 18 to 45 years have been enrolled. One patient received only a nasal dose because a chronic cardiac arrhythmia precluded safe completion of bronchoscopy. No significant vector-related toxicity or vector shedding has been observed. Several samples have shown evidence of DNA transfer and CFTR expression. Expression studies will be completely analyzed when the blinding is removed in April 1997, three months after the completion of the sixth cohort. We anticipate that this trial will provide information about the safety of AAV vectors in humans, and will provide an important first step in the study of AAV-mediated CF gene therapy.

Supported by grants from the NHLBI, NIDDK, NCRR, and CF Foundation.T.R.F., S.A., & W.B.G. may be entitled to patent royalty from products described herein.