Sweat chloride as a biomarker of CFTR activity: proof of concept and ivacaftor clinical trial data.

Background: We examined data from a Phase 2 trial {NCT00457821} of ivacaftor, a CFTR potentiator, in cystic fibrosis (CF) patients with aG551D mutation to evaluate standardized approaches to sweat chloride measurement and to explore the use of sweat chloride and nasal potential difference (NPD) to estimate CFTR activity.

Methods: Sweat chloride and NPD were secondary endpoints in this placebo-controlled, multicenter trial. Standardization of sweat collection, processing,and analysis was employed for the first time.

Optimizing nasal potential difference analysis for CFTR modulator development: assessment of ivacaftor in CF subjects with the G551D-CFTR mutation.

Nasal potential difference (NPD) is used as a biomarker of the cystic fibrosis transmembrane conductance regulator (CFTR) and epithelial sodium channel (ENaC) activity. We evaluated methods to detect changes in chloride and sodium transport by NPD based on a secondary analysis of a Phase II CFTR-modulator study. Thirty-nine subjects with CF who also had the G551D-CFTR mutation were randomized to receive ivacaftor (Kalydeco™; also known as VX-770) in four doses or placebo twice daily for at least 14 days.

Efficacy and safety of ivacaftor in patients aged 6 to 11 years with cystic fibrosis with a G551D mutation.

Rationale: Ivacaftor (VX-770), a cystic fibrosis transmembrane conductance regulator (CFTR) potentiator, has been shown to improve lung function, pulmonary exacerbation rate, respiratory symptoms, and weight gain compared with placebo in patients with cystic fibrosis aged 12 years or older with a G551D-CFTR mutation.

Objectives: This randomized, double-blind, placebo-controlled trial evaluated ivacaftor in patients with cystic fibrosis aged 6-11 years with a G551D-CFTR mutation on at least one allele.

Methods: Patients were randomly assigned to receive ivacaftor administered orally at 150 mg (n = 26) or placebo (n = 26) every 12 hours for 48 weeks in addition to existing prescribed cystic fibrosis therapies.

Ivacaftor in subjects with cystic fibrosis who are homozygous for the F508del-CFTR mutation.

Background: Ivacaftor (VX-770) is a cystic fibrosis transmembrane conductance regulator (CFTR) potentiator that was approved in the United States for the treatment of cystic fibrosis (CF) in patients ≥ 6 years of age who have a G551D mutation; however, the most prevalent disease-causing CFTR mutation, F508del, causes a different functional defect. The objectives of this study were to evaluate the safety of ivacaftor in a larger population and for a longer time period than tested previously and to assess the efficacy of ivacaftor in subjects with CF who are homozygous for F508del-CFTR.

Methods: This was a phase 2 study with a 16-week randomized (4:1), double-blind, placebo-controlled period (part A) and an open-label extension (part B) for subjects who met prespecified criteria.

Results of a phase IIa study of VX-809, an investigational CFTR corrector compound, in subjects with cystic fibrosis homozygous for the F508del-CFTR mutation.

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.

Effect of VX-770 in persons with cystic fibrosis and the G551D-CFTR mutation.

Background: A new approach in the treatment of cystic fibrosis involves improving the function of mutant cystic fibrosis transmembrane conductance regulator (CFTR). VX-770, a CFTR potentiator, has been shown to increase the activity of wild-type and defective cell-surface CFTR in vitro.

Methods: We randomly assigned 39 adults with cystic fibrosis and at least one G551D-CFTR allele to receive oral VX-770 every 12 hours at a dose of 25, 75, or 150 mg or placebo for 14 days (in part 1 of the study) or VX-770 every 12 hours at a dose of 150 or 250 mg or placebo for 28 days (in part 2 of the study).

Role of bacteriocins in mediating interactions of bacterial isolates taken from cystic fibrosis patients.

Pseudomonas aeruginosa (Pa) and Burkholderia cepacia complex (Bcc) lung infections are responsible for much of the mortality in cystic fibrosis (CF). However, little is known about the ecological interactions between these two, often co-infecting, species. This study provides what is believed to be the first report of the intra- and interspecies bacteriocin-like inhibition potential of Pa and Bcc strains recovered from CF patients.

Genome-wide study of Pseudomonas aeruginosa outer membrane protein immunogenicity using self-assembling protein microarrays.

Pseudomonas aeruginosa is responsible for potentially life-threatening infections in individuals with compromised defense mechanisms and those with cystic fibrosis. P. aeruginosa infection is notable for the appearance of a humoral response to some known antigens, such as flagellin C, elastase, alkaline protease, and others.

A virulence locus of Pseudomonas aeruginosa encodes a protein secretion apparatus.

Bacterial pathogens frequently use protein secretion to mediate interactions with their hosts. Here we found that a virulence locus (HSI-I) of Pseudomonas aeruginosa encodes a protein secretion apparatus. The apparatus assembled in discrete subcellular locations and exported Hcp1, a hexameric protein that forms rings with a 40 angstrom internal diameter.

The role of epitope specificity in the human opsonic antibody response to the staphylococcal surface polysaccharide poly N-acetyl glucosamine.

Background: The staphylococcal surface polysaccharide poly N-acetyl glucosamine (PNAG) is a target for killing and protective antibody in animals. We investigated the human antibody response and specificity of binding and opsonic antibodies for different epitopes on PNAG in serum samples from patients with cystic fibrosis (CF) colonized and not colonized with Staphylococcus aureus.

Methods: Serum samples from patients with CF colonized and not colonized with S.

The treatment of spine and chest wall deformities with fused ribs by expansion thoracostomy and insertion of vertical expandable prosthetic titanium rib: growth of thoracic spine and improvement of lung volumes.

Study Design: Prospective clinical trial of vertical expandable prosthetic titanium rib (VEPTR) in patients with combined spine and chest wall deformity with scoliosis and fused ribs.

Objective: Report the efficacy and safety of expansion thoracostomy and VEPTR surgery in the treatment of thoracic insufficiency syndrome (TIS) associated with fused ribs.

Summary Of Background Data: Traditional attitudes toward early-onset combined chest and spine deformity assume that thoracic deformity is best controlled by treatment directed at spine deformity, often involving early spinal arthrodesis.

Variability of markers of inflammation and infection in induced sputum in children with cystic fibrosis.

To determine reproducibility of inflammatory marker concentrations in induced sputum from subjects with cystic fibrosis (CF), 15 nonexpectorating children, 6 to 13 years of age with mild CF lung disease, underwent 3 weekly sputum inductions with 3% saline. Neutrophil elastase concentration and bacterial cultures were reproducible. This study provides useful information for investigators designing trials of anti-inflammatory therapies in CF involving sputum induction.

Inflammatory and microbiologic markers in induced sputum after intravenous antibiotics in cystic fibrosis.

Induced sputum has been used to study airway inflammation. We sought to determine whether markers of infection and inflammation in induced sputum were a useful and safe outcome measure in cystic fibrosis. We hypothesized that bacterial density and inflammatory content of induced sputum would decrease after antibiotic therapy.