Gene therapy for cystic fibrosis: which postman, which box?

Since 1989 when the gene responsible for cystic fibrosis was cloned and designated the cystic fibrosis transmembrane conductance regulator (CFTR) gene, considerable progress has been made in the development of gene therapy for this disease. Clinical trials have already been performed using cationic liposome and adenoviral based gene transfer systems, measuring the safety and efficacy of this new form of treatment, with variable results to date. These two approaches and the current progress in airway gene delivery are discussed.