Cationic lipid-mediated CFTR gene transfer to the lungs and nose of patients with cystic fibrosis: a double-blind placebo-controlled trial. Repeated aerosolized AAV-CFTR for treatment of cystic fibrosis: a randomized placebo-controlled phase 2B trial. Cystic fibrosis mutations and genotype-pulmonary phenotype analysis.
We and others have previously reported significant changes in chloride transport after cationic-lipid-mediated transfer of the cystic fibrosis transmembrane conductance regulator (CFTR) gene to the nasal epithelium of patients with cystic fibrosis. We studied the safety and efficacy of this gene transfer to the lungs and nose of patients with cystic fibrosis in a double-blind placebo-controlled trial.
                Eight patients with cystic fibrosis were randomly assigned DNA-lipid complex (active) by nebulisation into the lungs followed 1 week later by administration to the nose. Eight control patients followed the same protocol but with the lipid alone (placebo). Safety was assessed clinically, by radiography, by pulmonary function, by induced sputum, and by histological analysis. Efficacy was assessed by analysis of vector-specific CFTR DNA and mRNA, in-vivo potential difference, epifluorescence assay of chloride efflux, and bacterial adherence.
                Seven of the eight patients receiving the active complex reported mild influenza-like symptoms that resolved within 36 h. Six of eight patients in both the active and placebo groups reported mild airway symptoms over a period of 12 h following pulmonary administration. No specific treatment was required for either event. Pulmonary administration resulted in a significant (p<0.05) degree of correction of the chloride abnormality in the patients receiving active treatment but not in those on placebo when assessed by in-vivo potential difference and chloride efflux. Bacterial adherence was also reduced. We detected no alterations in the sodium transport abnormality. A similar pattern occurred following nasal administration.
                Cationic-lipid-mediated CFTR gene transfer can significantly influence the underlying chloride defect in the lungs of patients with cystic fibrosis. Previous studies have demonstrated that delivery of a recombinant adeno-associated virus (AAV) vector encoding the complete human cystic fibrosis transmembrane regulator (CFTR) cDNA (tgAAVCF) to the nose, sinus, and lungs of subjects with cystic fibrosis (CF) was safe and well tolerated. In a small randomized, double-blind study of three doses of aerosolized tgAAVCF or placebo at 30-day intervals, encouraging but non-significant trends in pulmonary function and induced sputum interleukin 8 (IL-8) levels were seen at early time points. This larger study was conducted to verify these trends. One hundred and two subjects aged 12 years and older with mild-to-moderate cystic fibrosis (forced expiratory flow in 1 sec [FEV1]:60% predicted) were randomized to two aerosolized doses of 1x10(13)DNase-resistant particles of tgAAVCF (n=51) or matching placebo (n=51) administered 30 days apart. Although tgAAVCF was well tolerated, the study did not meet its primary efficacy end point of statistically significant improvement in FEV1 30 days after initial administration of tgAAVCF compared with placebo. There were no significant differences in spirometric lung function over time, induced sputum biologic markers, or days of antibiotic use in either treatment group. Thus repeated doses of aerosolized tgAAVCF were safe and well tolerated, but did not result in significant improvement in lung function over time. Because gene transfer is the simplest, most basic way to correct the underlying genetic defect that leads to disease in CF, further research is warranted to develop an effective gene transfer agent for the treatment of CF. Although there are more than 1000 mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, most of them are uncommon and only limited information exists regarding genotype-pulmonary phenotype relationships.
                We determined and classified the CFTR mutations using denaturing high-performance liquid chromatography and developed new, quantitative methods to categorize pulmonary phenotypes.
                Two novel alleles were discovered, namely G1047R and 1525-2A-->G, which were accompanied by F508del and G551D mutations, respectively. Assessment of numerous options revealed that CF pulmonary phenotype categorization in children cannot be accomplished with clinical or pulmonary function data but is facilitated by longitudinal quantitative chest radiology. It was most useful to categorize pulmonary disease status by evaluating the typical pattern of abnormalities in patients homozygous for the F508del mutation, and then compare patients with minor mutations to this typical CF pulmonary phenotype. By this method, both patients with novel mutations have pulmonary phenotypes typical of F508del homozygotes. However, patients with class IV mutations (e.g., R347P) or with pancreatic sufficiency showed serial chest radiographs that were atypically mild.
                Longitudinal quantitative chest radiography provides a new strategy for CF pulmonary phenotype categorization that should be useful for genotype-phenotype delineation in individual patients and in both epidemiologic studies and clinical trials involving groups of children with CF.
There is currently no evidence to support the use of CFTR gene transfer reagents as a treatment for lung disease in people with cystic fibrosis. Future studies need to investigate clinically important outcome measures.