Background VX-809, a cystic fibrosis transmembrane conductance regulator (CFTR) modulator, has been shown to increase the cell surface density of functional F508del-CFTR in vitro. Methods A randomised, double-blind, placebo-controlled study evaluated the safety, tolerability and pharmacodynamics of VX-809 in adult patients with cystic fibrosis (n=89) who were homozygous for the F508del-CFTR mutation. Subjects were randomised to one of four VX-809 28 day dose groups (25, 50, 100 and 200 mg) or matching placebo. Results The type and incidence of adverse events were similar among VX-809- and placebo-treated subjects. Respiratory events were the most commonly reported and led to discontinuation by one subject in each active treatment arm. Pharmacokinetic data supported a once-daily oral dosing regimen. Pharmacodynamic data suggested that VX-809 improved CFTR function in at least one organ (sweat gland). VX-809 reduced elevated sweat chloride values in a dose-dependent manner (p=0.0013) that was statistically significant in the 100 and 200 mg dose groups. There was no statistically significant improvement in CFTR function in the nasal epithelium as measured by nasal potential difference, nor were there statistically significant changes in lung function or patient-reported outcomes. No maturation of immature F508del-CFTR was detected in the subgroup that provided rectal biopsy specimens. Conclusions In this study, VX-809 had a similar adverse event profile to placebo for 28 days in F508del-CFTR homozygous patients, and demonstrated biological activity with positive impact on CFTR function in the sweat gland. Additional data are needed to determine how improvements detected in CFTR function secondary to VX-809 in the sweat gland relate to those measurable in the respiratory tract and to long-term measures of clinical benefit. Clinical trial number NCT00865904

Traditionally, DNA used for PCR-based diagnostic analysis has originated from white cells fractionated from whole blood. Although this method yields substantial quantities of DNA, there are some drawbacks to the procedure, including the inconvenience of drawing blood, risk of exposure to blood-borne pathogens, liquid sample handling, and the somewhat involved extraction procedure. Alternatively, DNA for genetic diagnosis has been derived from finger stick blood samples, hair roots, cheek scrapings, and urine samples. Oral saline rinses have also been used extensively as a means of collecting buccal epithelial cells as a DNA source. However, this method still requires liquid sample handling. Herein, we present our results involving the rapid extraction of DNA from buccal cells collected on cytology brushes and swabs for use in PCR reactions, specifically the multiplex amplification of 5 exons within the CFTR gene. The quality of DNA isolated from buccal cells, collected in this manner, has been sufficient to reproducibly support multiplex amplification. Cheek cell samples and the DNA prepared from them as described here are highly stable. The success rate of PCR amplification on DNA prepared from buccal cells is 99%. In a blind study comparing the analysis of 12 mutations responsible for cystic fibrosis in multiplex products amplified with DNA from both blood and buccal cell samples from 464 individuals, there was 100% correlation of results for blood and cheek cell DNA, validating the use of DNA extracted from cheek cells collected on cytology brushes for use in genetic testing.

The short-term aerosol administration of a high dose of tobramycin in patients with clinically stable cystic fibrosis is an efficacious and safe treatment for endobronchial infection with P. aeruginosa.

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.

We tested the hypothesis that features of upper airway and tracheal geometry can be inferred from acoustic reflection data recorded at the mouth. In six subjects we computed inferences of airway cross-sectional area vs. distance and compared them with measurements obtained from orthogonal radiographic projections of the trachea. The acoustic data show local area maxima at the uvula and hypopharynx and local minima at the oropharynx and the glottis. With subjects breathing air the inferred tracheal areas markedly exceeded the radiographic measurements. With subjects breathing 80% He-20% O2 there was good intrasubject agreement between acoustic and radiographic data in spite of large intersubject variability. The average coefficient of variation of tracheal area determinations for five trials in all subjects was 0.16. These studies suggest that features of airway geometry between the mouth and carina can be determined accurately and noninvasively in individual subjects from high-frequency reflection data measured at the mouth.