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Background: The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in individuals with cystic fibrosis (CF) has increased significantly. While studies demonstrate that persistent MRSA infection in CF is associated with poor clinical outcomes, there are no randomized controlled studies informing management., Methods: The Persistent MRSA Eradication Protocol was a double-blind, randomized, placebo-controlled study investigating a comprehensive 28-day treatment regimen with or without inhaled vancomycin for eradication of MRSA. Eligible participants had CF and documented persistent MRSA infection. All participants received oral antibiotics, topical decontamination, and environmental cleaning and were randomized to receive inhaled vancomycin or inhaled placebo. The primary outcome was the difference in MRSA eradication rates one month after completion of the treatment protocol., Results: 29 participants were randomized. Four subjects in the inhaled vancomycin group required withdrawal from the study for bronchospasm before outcome data were collected and were excluded from analysis. There was no difference in the primary outcome: 2/10 (20%) of subjects in the intervention group and 3/15 (20%) in the placebo group had a MRSA negative sputum culture one month after treatment. There were no statistically significant differences in the rates of MRSA eradication at the end of treatment or three months after treatment completion., Conclusions: This study suggests that persistent MRSA infection is difficult to eradicate, even with multimodal antibiotics. The use of a single course of inhaled vancomycin may not lead to higher rates of MRSA eradication in individuals with CF and may be associated with bronchospasm. FUND: This trial was financially supported by the Cystic Fibrosis Foundation., (Copyright © 2018 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.)

Background: Improved lung function and fewer pulmonary exacerbations (PEx) were observed with lumacaftor/ivacaftor (LUM/IVA) in patients with cystic fibrosis homozygous for F508del. It is unknown whether PEx reduction extends to patients without early lung function improvement., Methods: Post hoc analyses of pooled phase 3 data (NCT01807923, NCT01807949) categorized LUM/IVA-treated patients by percent predicted forced expiratory volume in 1 s (ppFEV 1 ) change from baseline to day 15 into threshold categories (absolute change ≤0 vs >0; relative change <5% vs ≥5%) and compared PEx rates vs placebo., Results: LUM (400 mg q12h)/IVA (250 mg q12h)-treated patients (n = 369) experienced significantly fewer PEx vs placebo, regardless of threshold category. With LUM/IVA, PEx rate per patient per year was 0.60 for those with absolute change in ppFEV 1  > 0 and 0.85 for those with absolute change ≤0 (respective rate ratios vs placebo [95% CI]: 0.53 [0.40-0.69; P < .0001], 0.74 [0.55-0.99; P = .04])., Conclusions: LUM/IVA significantly reduced PEx, even in patients without early lung function improvement., (Copyright © 2018 The Author(s). Published by Elsevier B.V. All rights reserved.)

Background: New drugs that improve the function of the cystic fibrosis transmembrane conductance regulator (CFTR) protein with discreet disease-causing variants have been successfully developed for cystic fibrosis (CF) patients. Preclinical model systems have played a critical role in this process, and have the potential to inform researchers and CF healthcare providers regarding the nature of defects in rare CFTR variants, and to potentially support use of modulator therapies in new populations., Methods: The Cystic Fibrosis Foundation (CFF) assembled a workshop of international experts to discuss the use of preclinical model systems to examine the nature of CF-causing variants in CFTR and the role of in vitro CFTR modulator testing to inform in vivo modulator use. The theme of the workshop was centered on CFTR theratyping, a term that encompasses the use of CFTR modulators to define defects in CFTR in vitro, with application to both common and rare CFTR variants., Results: Several preclinical model systems were identified in various stages of maturity, ranging from the expression of CFTR variant cDNA in stable cell lines to examination of cells derived from CF patients, including the gastrointestinal tract, the respiratory tree, and the blood. Common themes included the ongoing need for standardization, validation, and defining the predictive capacity of data derived from model systems to estimate clinical outcomes from modulator-treated CF patients., Conclusions: CFTR modulator theratyping is a novel and rapidly evolving field that has the potential to identify rare CFTR variants that are responsive to approved drugs or drugs in development., (Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: The ability to restore cystic fibrosis transmembrane regulator (CFTR) function with effective small molecule modulators in patients with cystic fibrosis provides an opportunity to study relationships between CFTR ion channel function, organ level physiology, and clinical outcomes., Methods: We performed a multisite, prospective, observational study of ivacaftor, prescribed in patients with the G551D-CFTR mutation. Measurements of lung mucociliary clearance (MCC) were performed before and after treatment initiation (1 and 3 months), in parallel with clinical outcome measures., Results: Marked acceleration in whole lung, central lung, and peripheral lung MCC was observed 1 month after beginning ivacaftor and was sustained at 3 months. Improvements in MCC correlated with improvements in forced expiratory volume in the first second (FEV1) but not sweat chloride or symptom scores., Conclusions: Restoration of CFTR activity with ivacaftor led to significant improvements in MCC. This physiologic assessment provides a means to characterize future CFTR modulator therapies and may help to predict improvements in lung function., Trial Registration: ClinicialTrials.gov, NCT01521338., Funding: CFF Therapeutics (GOAL11K1).

Background: Aspergillus species are increasingly detected in the respiratory tracts of individuals with cystic fibrosis (CF), and chronic Aspergillus fumigatus is associated with more frequent hospitalizations for pulmonary exacerbations. However, patient and clinical factors that may contribute to the acquisition of persistent Aspergillus infection have yet to be identified. The objective of this study was to identify risk factors for development of Aspergillus respiratory isolation in CF., Methods: A retrospective cohort study of participants in the CF Foundation Patient Registry between 2006 and 2012 was conducted. Generalized estimating equation models were used to evaluate the association between the development of persistent Aspergillus respiratory isolation and individual level demographic and clinical characteristics., Results: Among 16,095 individuals with CF followed from 2006 to 2012, 1541 (9.6%) subjects developed persistent Aspergillus isolation. White race (Odds Ratio [OR] 1.74, 95% confidence interval 1.23, 2.48, p<0.001) and pancreatic insufficiency (OR 1.50, 95% CI 1.09, 2.06, p<0.001) were found to be risk factors for persistent Aspergillus isolation. Chronic therapies, including inhaled antibiotics (OR 1.33; 95% CI 1.21, 1.46), macrolides (OR 1.23, 95% CI 1.14, 1.32, p<0.001), and inhaled corticosteroids (OR 1.13, 95% CI 1.04, 1.20, p<0.001) were also independently associated with an increased risk for persistent Aspergillus isolation., Conclusions: We identified macrolides and inhaled antibiotics, which individually have been shown to improve CF outcomes, and inhaled corticosteroids as risk factors for developing persistent Aspergillus isolation. Further work is needed to determine whether these associations are causal or due to confounding by other factors., (Copyright © 2018 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.)

Background: Small-colony variants (SCVs) are a distinct phenotype of Staphylococcus aureus, known for their role in chronic, difficult to treat infections, including cystic fibrosis (CF) lung disease. The goal of this study was to characterize SCV MRSA infection in an adult and pediatric CF population and to identify antibiotic susceptibility patterns unique to SCV MRSA., Methods: We recovered methicillin-resistant S. aureus (MRSA) from respiratory culture samples from CF patients at the Johns Hopkins Hospital during a 6month study period., Results: Of 1161 samples, 200 isolates (17%) were identified as MRSA, and 37 isolates from 28 patients were identified as SCV MRSA. A higher proportion of MRSA was found among SCV isolates (37/66, 56%) compared to normal colony variant (NCV) isolates (163/417, 39%), p=0.02. All SCV MRSA isolates from individual patients were susceptible to vancomycin and ceftaroline, but they demonstrated higher rates of antibiotic resistance to trimethoprim/sulfamethoxazole, moxifloxacin, and erythromycin, compared to NCV MRSA isolates. Additionally, individuals with SCV MRSA had lower lung function, higher rates of persistent MRSA infection, and higher rates of previous antibiotic use, compared to individuals with NCV MRSA., Conclusions: A significant proportion of MRSA isolates recovered from patients with CF have the SCV morphology. Compared to individuals with NCV MRSA, those with SCV MRSA have higher rates of persistent MRSA infection and lower lung function. SCV MRSA isolates were more resistant than NCV, but they are highly susceptible to vancomycin, linezolid and ceftaroline., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Rationale: The severity of cystic fibrosis (CF) lung disease varies widely, even for Phe508del homozygotes. Heritability studies show that more than 50% of the variability reflects non-cystic fibrosis transmembrane conductance regulator (CFTR) genetic variation; however, the full extent of the pertinent genetic variation is not known., Objectives: We sought to identify novel CF disease-modifying mechanisms using an integrated approach based on analyzing "in vivo" CF airway epithelial gene expression complemented with genome-wide association study (GWAS) data., Methods: Nasal mucosal RNA from 134 patients with CF was used for RNA sequencing. We tested for associations of transcriptomic (gene expression) data with a quantitative phenotype of CF lung disease severity. Pathway analysis of CF GWAS data (n = 5,659 patients) was performed to identify novel pathways and assess the concordance of genomic and transcriptomic data. Association of gene expression with previously identified CF GWAS risk alleles was also tested., Measurements and Main Results: Significant evidence of heritable gene expression was identified. Gene expression pathways relevant to airway mucosal host defense were significantly associated with CF lung disease severity, including viral infection, inflammation/inflammatory signaling, lipid metabolism, apoptosis, ion transport, Phe508del CFTR processing, and innate immune responses, including HLA (human leukocyte antigen) genes. Ion transport and CFTR processing pathways, as well as HLA genes, were identified across differential gene expression and GWAS signals., Conclusions: Transcriptomic analyses of CF airway epithelia, coupled to genomic (GWAS) analyses, highlight the role of heritable host defense variation in determining the pathophysiology of CF lung disease. The identification of these pathways provides opportunities to pursue targeted interventions to improve CF lung health.

Rationale: Individuals with cystic fibrosis (CF) experience frequent acute pulmonary exacerbations, which lead to decreased lung function and reduced quality of life., Objectives: The goal of this study was to determine if an intervention directed toward early detection of pulmonary exacerbations using home spirometry and symptom monitoring would result in slower decline in lung function than in control subjects., Methods: We conducted a multicenter, randomized trial at 14 CF centers with subjects at least 14 years old. The early intervention arm subjects measured home spirometry and symptoms electronically twice per week. Sites were notified if a participant met criteria for an exacerbation and contacted participants to determine if treatment for acute exacerbation was required. Participants in the usual care arm were seen every 3 months and were asked to contact the site if they were concerned about worsening pulmonary symptoms., Measurements and Main Results: The primary outcome was the 52-week change in FEV 1 . Secondary outcomes included time to first exacerbation and subsequent exacerbation, quality of life, and change in weight. A total of 267 patients were randomized, and the study arms were well matched at baseline. There was no significant difference between study arms in 52-week mean change in FEV 1 slope (mean slope difference, 0.00 L, 95% confidence interval, -0.07 to 0.07; P = 0.99). The early intervention arm subjects detected exacerbations more frequently than usual care arm subjects (time to first exacerbation hazard ratio, 1.45; 95% confidence interval, 1.09 to 1.93; P = 0.01). Adverse events were not significantly different between treatment arms., Conclusions: An intervention of home monitoring among patients with CF was able to detect more exacerbations than usual care, but this did not result in slower decline in lung function. Clinical trial registered with www.clinicaltrials.gov (NCT01104402).

Background: Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as an important pathogen in cystic fibrosis (CF). Over 25% of individuals in the United States with CF are found to have MRSA in respiratory culture specimens, and persistent MRSA infection has been associated with more rapid decline in lung function and increased mortality. The objective of this study was to investigate clinical and demographic characteristics that are associated with the development of persistent MRSA infection in a CF population., Methods: This was a retrospective cohort study of individuals followed from 2002 to 2012 in the Cystic Fibrosis Foundation Patient Registry. A time-to-event analysis for the development of persistent MRSA infection was performed, and multivariable Cox proportional hazards models were constructed to identify risk factors for infection., Results: The study cohort included 19,434 individuals, of which 5844 would develop persistent MRSA infection. In the adjusted model, pancreatic insufficiency (HR: 1.49; 95% CI: 1.29-1.72), CF related diabetes (HR: 1.13; 95% CI: 1.05-1.20), co-infection with P. aeruginosa (HR: 1.21; 95% CI: 1.13-1.28), and number of hospitalizations/year (HR: 1.09; 95% CI: 1.06-1.12) were all associated with increased risk, whereas higher socio-economic status (HR: 0.87; 95% CI: 0.82-0.93) was associated with a lower risk. Receiving care at a CF center with increased MRSA prevalence was associated with increased risk of MRSA infection: highest quartile (HR: 2.33; 95% CI: 2.13-2.56)., Conclusions: No easily modifiable risk factors for persistent MRSA were identified in this study. However, several risk factors for patients at higher risk for persistent MRSA infection were identified, for example centers with a high baseline MRSA prevalence, and may be useful in designing center-specific MRSA infection prevention and control strategies and/or eradication protocols. Additional studies are needed in order to evaluate if attention to these risk factors can improve clinical outcomes., (Copyright © 2017 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.)

Background: New CFTR modulators are in development that sponsors anticipate will be comparable or superior to approved modulators. Testing these agents for efficacy will require either placebo-controlled or active-comparator trials., Methods: We surveyed US CF physicians and their patients eligible to receive approved modulators or their families for willingness to participate in placebo-controlled modulator trials of varying duration., Results: Interest in placebo-controlled trials of short duration (2-4weeks) was greatest, with few respondents, particularly among patient respondents, willing to consider 6month studies. Patients/families with access to approved modulators were consistently less interested in placebo-controlled modulator trials of any duration., Conclusions: Sample size and interpretability advantages of placebo-controlled trials outweigh alternative active-comparator trials, but must consider physician and patient thresholds for forgoing treatment with approved modulators. Enrollment will be most feasible for short-duration trials and those conducted among populations without access to approved modulators., (Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.)

Rationale: In a prior study, lumacaftor/ivacaftor treatment (≤28 d) in patients with cystic fibrosis (CF) heterozygous for F508del-CFTR did not improve lung function., Objectives: To evaluate an optimized lumacaftor/ivacaftor dosing regimen with a longer duration in a cohort of patients heterozygous for F508del-CFTR., Methods: Patients aged 18 years or older with a confirmed CF diagnosis and percent predicted FEV 1 (ppFEV 1 ) of 40 to 90 were randomized to lumacaftor/ivacaftor (400 mg/250 mg every 12 h) or placebo daily for 56 days. Primary outcomes were change in ppFEV 1 at Day 56 and safety. Other disease markers were evaluated., Measurements and Main Results: Of 126 patients, 119 (94.4%) completed the study. Lumacaftor/ivacaftor was well tolerated, although chest tightness and dyspnea occurred more frequently with active treatment than with placebo (27.4% vs. 14.3% and 14.5% vs. 6.3%, respectively). Mean (SD) ppFEV 1 values at baseline were 62.9 (14.3) in the active treatment group and 60.1 (14.0) in the placebo group. Absolute changes in ppFEV 1 (least squares mean [SE]) at Day 56 were -0.6 (0.8) percentage points in the active treatment group and -1.2 (0.8) percentage points in the placebo group (P = 0.60). CF respiratory symptom scores in the active treatment group improved by a mean of 5.7 points versus a decrease of -0.8 in the placebo group (P < 0.01). No changes in body mass index occurred. Changes from baseline in sweat chloride (least squares mean [SE]) at Day 56 were -11.8 (1.3) mmol/L in the active treatment group and -0.8 (1.2) mmol/L in the placebo group (P < 0.0001)., Conclusions: Sweat chloride and respiratory symptom scores improved with lumacaftor/ivacaftor, though no meaningful benefit was seen in ppFEV 1 or body mass index in patients heterozygous for F508del-CFTR. Clinical trial registered with www.clinicaltrials.gov (NCT01225211).

Rationale: Cystic fibrosis (CF) lung disease progresses by a combination of airway inflammation, bacterial colonization, and infection. Airway inflammation is predominantly neutrophilic and complicates airway clearance therapies through cellular debris; excessive DNA; excessive and viscous mucus; and high concentrations of neutrophils, IL-8, and related cytokines liberated along the nuclear factor-κB signaling pathway., Objectives: We conducted a preliminary, single-site, randomized, double-blind, placebo-controlled study to evaluate the effects over 28 days of two dose levels (0.05 mg and 0.1 mg daily) of an older cardiac glycoside, digitoxin, as compared with placebo, on safety, pharmacokinetics, and inflammatory markers in induced sputum obtained from 24 subjects with mild to moderate CF lung disease., Methods: Patients with CF 18-45 years old with any genotype combination were eligible. The primary objective was to measure the effects of digitoxin on IL-8 and neutrophil counts in induced sputum. Secondary objectives were to measure (1) the pharmacokinetics of digitoxin in sera of patients with stable CF; (2) safety indices, including ECG changes and sputum microbiology; (3) the effect of digitoxin on gene expression in nasal epithelial cells of patients with stable CF; and (4) quality-of-life scores using the Cystic Fibrosis Questionnaire-Revised., Measurements and Main Results: It took several weeks to achieve a therapeutic serum level of digitoxin in subjects with CF. No safety concerns emerged during the study. Digitoxin treatment showed a trend toward reduction in sputum free neutrophil elastase and neutrophil counts, but not a reduction in sputum IL-8. Digitoxin treatment did not reach statistical significance for the primary or secondary outcome measures over the 28-day study period. However, the nasal mRNA from the group receiving 0.1 mg of digitoxin daily had a distinct distribution of global gene expression levels as compared with either the 0.05-mg dose or placebo treatment. The mRNAs encoding chemokine/cytokine or cell surface receptors in immune cells were decreased in nasal epithelial cells at the higher dose, leading to pathway-mediated reductions in IL-8, IL-6, lung epithelial inflammation, neutrophil recruitment, and mucus hypersecretion., Conclusions: At a dose of 0.1 mg daily for 28 days, digitoxin was safe for adults with CF lung disease, but it did not achieve a significant decrease in sputum inflammatory markers. Clinical trial registered with www.clinicaltrials.gov (NCT00782288).

The stasis of mucus secretions in the lungs of cystic fibrosis (CF) patients leads to recurrent infections and pulmonary exacerbations, resulting in decreased survival. Prior studies have assessed the biochemical and biophysical features of airway mucus in individuals with CF. However, these measurements are unable to probe mucus structure on microscopic length scales relevant to key players in the progression of CF-related lung disease, namely, viruses, bacteria, and neutrophils. In this study, we quantitatively determined sputum microstructure based on the diffusion of muco-inert nanoparticle probes in CF sputum and found that a reduction in sputum mesh pore size is characteristic of CF patients with reduced lung function, as indicated by measured FEV 1 . We also discovered that the effect of ex vivo treatment of CF sputum with rhDNase I (Pulmozyme) on microstructure is dependent upon the time interval between the most recent inhaled rhDNase I treatment and the sample collection. Microstructure of mucus may serve as a marker for the extent of CF lung disease and as a parameter for assessing the effectiveness of mucus-altering agents., Competing Interests: The mucus-penetrating particle technology described in this publication is being developed by Kala Pharmaceuticals. J. Hanes is a cofounder of Kala Pharmaceuticals. He owns company stock, which is subject to certain restrictions under Johns Hopkins University policy. The terms of this arrangement are being managed by Johns Hopkins University in accordance with its conflict-of-interest policies.

Background: Lumacaftor/ivacaftor combination therapy has shown clinical benefits in patients with cystic fibrosis homozygous for the Phe508del CFTR mutation; however, pretreatment lung function is a confounding factor that potentially affects the efficacy and safety of this therapy. We aimed to assess the efficacy and safety of lumacaftor/ivacaftor therapy in these patients, defined by specific categories of lung function., Methods: Both trials (TRAFFIC and TRANSPORT) included in this pooled analysis were multinational, randomised, double-blind, placebo-controlled, parallel-group, phase 3 studies. Eligible patients from 187 participating centres in North America, Australia, and the European Union (both trials) were aged 12 years or older with a confirmed diagnosis of cystic fibrosis, homozygous for the Phe508del CFTR mutation, and with a percent predicted FEV1 (ppFEV1) of 40-90 at the time of screening. Patients were randomly assigned with an interactive web response system (1:1:1) to receive placebo, lumacaftor (600 mg once daily) plus ivacaftor (250 mg every 12 h), or lumacaftor (400 mg every 12 h) plus ivacaftor (250 mg every 12 h) for 24 weeks. Prespecified subgroup analyses of pooled efficacy and safety data by lung function, as measured by ppFEV1, were done for patients with baseline ppFEV1 (<40 and ≥40) and screening ppFEV1 (<70 and ≥70). The primary endpoint was the absolute change from baseline in ppFEV1 at week 24 analysed in all randomised patients who received at least one dose of study drug. Both trials are registered with ClinicalTrials.gov (TRAFFIC: NCT01807923; TRANSPORT: NCT01807949)., Findings: Both trials were done between April, 2013, and April, 2014. Of the 1108 patients included in the efficacy analysis, 81 patients had a ppFEV1 that decreased to lower than 40 between screening and baseline and 1016 had a ppFEV1 of 40 or higher at baseline. At screening, 730 had a ppFEV1 of less than 70, and 342 had a ppFEV1 of 70 or higher. Improvements in the absolute change from baseline at week 24 in ppFEV1 were observed with both lumacaftor/ivacaftor doses in the subgroup with baseline ppFEV1 levels lower than 40 (least-squares mean difference vs placebo was 3·7 percentage points [95% CI 0·5-6·9; p=0·024] in the lumacaftor [600 mg/day]-ivacaftor group and 3·3 percentage points [0·2-6·4; p=0·036] in the lumacaftor [400 mg/12 h]-ivacaftor group). Improvements in ppFEV1 compared with placebo were also reported in the subgroup with baseline ppFEV1 levels of 40 or higher (3·3 percentage points [2·3-4·4; p<0·0001] in the lumacaftor [600 mg per day]-ivacaftor group and 2·8 percentage points [1·7-3·8; p<0·0001] in the lumacaftor [400 mg/12 h]-ivacaftor group). Similar absolute improvements in ppFEV1 compared with placebo were observed in subgroups with screening ppFEV1 levels lower than 70 and ppFEV1 levels of 70 or higher. Increases in body-mass index and reduction in number of pulmonary exacerbation events were observed in both lumacaftor/ivacaftor dose groups compared with placebo across all lung function subgroups. Treatment was generally well tolerated, although the incidence of some respiratory adverse events was higher with lumacaftor/ivacaftor than with placebo in all subgroups. In patients with baseline ppFEV1 levels lower than 40, these adverse events included cough, dyspnoea, and abnormal respiration., Interpretation: These analyses confirm that lumacaftor/ivacaftor combination therapy benefits patients with cystic fibrosis homozygous for Phe508del CFTR who have varying degrees of lung function impairment., Funding: Vertex Pharmaceuticals., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Cystic fibrosis (CF) is a life-shortening genetic disease affecting approximately 70,000 individuals worldwide. Until recently, drug development efforts have emphasised therapies treating downstream signs and symptoms resulting from the underlying CF biological defect: reduced function of the CF transmembrane conductance regulator (CFTR) protein. The current CF drug development landscape has expanded to include therapies that enhance CFTR function by either restoring wild-type CFTR protein expression or increasing (modulating) the function of mutant CFTR proteins in cells. To date, two systemic small-molecule CFTR modulators have been evaluated in pivotal clinical trials in individuals with CF and specific mutant CFTR genotypes that have led to regulatory review and/or approval. Advances in the discovery of CFTR modulators as a promising new class of therapies have been impressive, yet work remains to develop highly effective, disease-modifying modulators for individuals of all CF genotypes. The objectives of this review are to outline the challenges and opportunities in drug development created by systemic genotype-specific CFTR modulators, highlight the advantages of sweat chloride as an established biomarker of CFTR activity to streamline early-phase development and summarise options for later phase clinical trial designs that respond to the adoption of approved genotype-specific modulators into standard of care. An optimal development framework will be needed to move the most promising therapies efficiently through the drug development pipeline and ultimately deliver efficacious and safe therapies to all individuals with CF., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/)

Background: Cystic fibrosis is a life-limiting disease that is caused by defective or deficient cystic fibrosis transmembrane conductance regulator (CFTR) protein activity. Phe508del is the most common CFTR mutation., Methods: We conducted two phase 3, randomized, double-blind, placebo-controlled studies that were designed to assess the effects of lumacaftor (VX-809), a CFTR corrector, in combination with ivacaftor (VX-770), a CFTR potentiator, in patients 12 years of age or older who had cystic fibrosis and were homozygous for the Phe508del CFTR mutation. In both studies, patients were randomly assigned to receive either lumacaftor (600 mg once daily or 400 mg every 12 hours) in combination with ivacaftor (250 mg every 12 hours) or matched placebo for 24 weeks. The primary end point was the absolute change from baseline in the percentage of predicted forced expiratory volume in 1 second (FEV1) at week 24., Results: A total of 1108 patients underwent randomization and received study drug. The mean baseline FEV1 was 61% of the predicted value. In both studies, there were significant improvements in the primary end point in both lumacaftor-ivacaftor dose groups; the difference between active treatment and placebo with respect to the mean absolute improvement in the percentage of predicted FEV1 ranged from 2.6 to 4.0 percentage points (P<0.001), which corresponded to a mean relative treatment difference of 4.3 to 6.7% (P<0.001). Pooled analyses showed that the rate of pulmonary exacerbations was 30 to 39% lower in the lumacaftor-ivacaftor groups than in the placebo group; the rate of events leading to hospitalization or the use of intravenous antibiotics was lower in the lumacaftor-ivacaftor groups as well. The incidence of adverse events was generally similar in the lumacaftor-ivacaftor and placebo groups. The rate of discontinuation due to an adverse event was 4.2% among patients who received lumacaftor-ivacaftor versus 1.6% among those who received placebo., Conclusions: These data show that lumacaftor in combination with ivacaftor provided a benefit for patients with cystic fibrosis homozygous for the Phe508del CFTR mutation. (Funded by Vertex Pharmaceuticals and others; TRAFFIC and TRANSPORT ClinicalTrials.gov numbers, NCT01807923 and NCT01807949.).

Gene therapy has emerged as an alternative for the treatment of diseases refractory to conventional therapeutics. Synthetic nanoparticle-based gene delivery systems offer highly tunable platforms for the delivery of therapeutic genes. However, the inability to achieve sustained, high-level transgene expression in vivo presents a significant hurdle. The respiratory system, although readily accessible, remains a challenging target, as effective gene therapy mandates colloidal stability in physiological fluids and the ability to overcome biological barriers found in the lung. We formulated highly stable DNA nanoparticles based on state-of-the-art biodegradable polymers, poly(β-amino esters) (PBAEs), possessing a dense corona of polyethylene glycol. We found that these nanoparticles efficiently penetrated the nanoporous and highly adhesive human mucus gel layer that constitutes a primary barrier to reaching the underlying epithelium. We also discovered that these PBAE-based mucus-penetrating DNA nanoparticles (PBAE-MPPs) provided uniform and high-level transgene expression throughout the mouse lungs, superior to several gold standard gene delivery systems. PBAE-MPPs achieved robust transgene expression over at least 4 mo following a single administration, and their transfection efficiency was not attenuated by repeated administrations, underscoring their clinical relevance. Importantly, PBAE-MPPs demonstrated a favorable safety profile with no signs of toxicity following intratracheal administration.

Gene therapy has not yet improved cystic fibrosis (CF) patient lung function in human trials, despite promising preclinical studies. In the human CF lung, inhaled gene vectors must penetrate the viscoelastic secretions coating the airways to reach target cells in the underlying epithelium. We investigated whether CF sputum acts as a barrier to leading adeno-associated virus (AAV) gene vectors, including AAV2, the only serotype tested in CF clinical trials, and AAV1, a leading candidate for future trials. Using multiple particle tracking, we found that sputum strongly impeded diffusion of AAV, regardless of serotype, by adhesive interactions and steric obstruction. Approximately 50% of AAV vectors diffused >1,000-fold more slowly in sputum than in water, with large patient-to-patient variation. We thus tested two strategies to improve AAV diffusion in sputum. We showed that an AAV2 mutant engineered to have reduced heparin binding diffused twice as fast as AAV2 on average, presumably because of reduced adhesion to sputum. We also discovered that the mucolytic N-acetylcysteine could markedly enhance AAV diffusion by altering the sputum microstructure. These studies underscore that sputum is a major barrier to CF gene delivery, and offer strategies for increasing AAV penetration through sputum to improve clinical outcomes.

Background: The phe508del CFTR mutation causes cystic fibrosis by limiting the amount of CFTR protein that reaches the epithelial cell surface. We tested combination treatment with lumacaftor, an investigational CFTR corrector that increases trafficking of phe508del CFTR to the cell surface, and ivacaftor, a CFTR potentiator that enhances chloride transport of CFTR on the cell surface., Methods: In this phase 2 clinical trial, we assessed three successive cohorts, with the results of each cohort informing dose selection for the subsequent cohort. We recruited patients from 24 cystic fibrosis centres in Australia, Belgium, Germany, New Zealand, and the USA. Eligibility criteria were: confirmed diagnosis of cystic fibrosis, age at least 18 years, and a forced expiratory volume in 1 s (FEV1) of 40% or more than predicted. Cohort 1 included phe508del CFTR homozygous patients randomly assigned to either lumacaftor 200 mg once per day for 14 days followed by addition of ivacaftor 150 mg or 250 mg every 12 h for 7 days, or 21 days of placebo. Together, cohorts 2 and 3 included phe508del CFTR homozygous and heterozygous patients, randomly assigned to either 56 days of lumacaftor (cohort 2: 200 mg, 400 mg, or 600 mg once per day, cohort 3: 400 mg every 12 h) with ivacaftor 250 mg every 12 h added after 28 days, or 56 days of placebo. The primary outcomes for all cohorts were change in sweat chloride concentration during the combination treatment period in the intention-to-treat population and safety (laboratory measurements and adverse events). The study is registered with ClinicalTrials.gov, number NCT01225211, and EudraCT, number 2010-020413-90., Findings: Cohort 1 included 64 participants. Cohort 2 and 3 combined contained 96 phe508del CFTR homozygous patients and 28 compound heterozygotes. Treatment with lumacaftor 200 mg once daily and ivacaftor 250 mg every 12 h decreased mean sweat chloride concentration by 9.1 mmol/L (p<0.001) during the combination treatment period in cohort 1. In cohorts 2 and 3, mean sweat chloride concentration did not decrease significantly during combination treatment in any group. Frequency and nature of adverse events were much the same in the treatment and placebo groups during the combination treatment period; the most commonly reported events were respiratory. 12 of 97 participants had chest tightness or dyspnoea during treatment with lumacaftor alone. In pre-planned secondary analyses, a significant decrease in sweat chloride concentration occurred in the treatment groups between day 1 and day 56 (lumacaftor 400 mg once per day group -9.1 mmol/L, p<0.001; lumacaftor 600 mg once per day group -8.9 mmol/L, p<0.001; lumacaftor 400 mg every 12 h group -10.3 mmol/L, p=0.002). These changes were significantly greater than the change in the placebo group. In cohort 2, the lumacaftor 600 mg once per day significantly improved FEV1 from day 1 to 56 (difference compared with placebo group: +5.6 percentage points, p=0.013), primarily during the combination period. In cohort 3, FEV1 did not change significantly across the entire study period compared with placebo (difference +4.2 percentage points, p=0.132), but did during the combination period (difference +7.7 percentage points, p=0·003). Phe508del CFTR heterozygous patients did not have a significant improvement in FEV1., Interpretation: We provide evidence that combination lumacaftor and ivacaftor improves FEV1 for patients with cystic fibrosis who are homozygous for phe508del CFTR, with a modest effect on sweat chloride concentration. These results support the further exploration of combination lumacaftor and ivacaftor as a treatment in this setting., Funding: Vertex Pharmaceuticals, Cystic Fibrosis Foundation Therapeutics Development Network., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Background: The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) respiratory infection in cystic fibrosis (CF) has increased dramatically over the last decade, and is now affecting approximately 25% of patients. Epidemiologic evidence suggests that persistent infection with MRSA results in an increased rate of decline in FEV1 and shortened survival. Currently, there are no conclusive studies demonstrating an effective and safe treatment protocol for persistent MRSA respiratory infection in CF., Methods/design: The primary objective of this study is to evaluate the safety and efficacy of a 28-day course of vancomycin for inhalation in combination with oral antibiotics in eliminating MRSA from the respiratory tract of individuals with CF and persistent MRSA infection. This is a two-center, randomized, double-blind, comparator-controlled, parallel-group study with 1:1 assignment to either vancomycin for inhalation (250 mg twice a day) or taste-matched placebo for 28 days in individuals with cystic fibrosis. In addition, both groups will receive oral rifampin, a second oral antibiotic - trimethoprim/sulfamethoxazole (TMP/SMX) or doxycycline, protocol determined - mupirocin intranasal cream, and chlorhexidine body washes. Forty patients with persistent respiratory tract MRSA infection will be enrolled: 20 will be randomized to vancomycin for inhalation and 20 to a taste-matched placebo. The primary outcome will be the presence of MRSA in sputum respiratory tract cultures 1 month after the conclusion of treatment. Secondary outcomes include the efficacy of the intervention on: FEV1% predicted, patient reported outcomes, pulmonary exacerbations, and MRSA colony-forming units found in respiratory tract sample culture., Discussion: Results of this study will provide guidance to clinicians regarding the safety and effectiveness of a targeted eradication strategy for persistent MRSA infection in CF., Trial Registration: This trial is registered at ClinicalTrials.gov (NCT01594827, received 05/07/2012) and is funded by the Cystic Fibrosis Foundation (Grants: PMEP10K1 and PMEP11K1).

Benchmarking is the process of using outcome data to identify high-performing centres and determine practices associated with their outstanding performance. The US Cystic Fibrosis Foundation (CFF) Patient Registry contains centre-specific outcomes data for all CFF-certified paediatric and adult cystic fibrosis (CF) care programmes in the USA. The CFF benchmarking project analysed these registry data, adjusting for differences in patient case mix known to influence outcomes, and identified the top-performing US paediatric and adult CF care programmes for pulmonary and nutritional outcomes. Separate multidisciplinary paediatric and adult benchmarking teams each visited 10 CF care programmes, five in the top quintile for pulmonary outcomes and five in the top quintile for nutritional outcomes. Key practice patterns and approaches present in both paediatric and adult programmes with outstanding clinical outcomes were identified and could be summarised as systems, attitudes, practices, patient/family empowerment and projects. These included: (1) the presence of strong leadership and a well-functioning care team working with a systematic approach to providing consistent care; (2) high expectations for outcomes among providers and families; (3) early and aggressive management of clinical declines, avoiding reliance on 'rescues'; and (4) patients/families that were engaged, empowered and well informed on disease management and its rationale. In summary, assessment of practice patterns at CF care centres with top-quintile pulmonary and nutritional outcomes provides insight into characteristic practices that may aid in optimising patient outcomes.

Cystic fibrosis (CF) is a multisystem disease causing severe chronic sinopulmonary disease and loss of pancreatic exocrine function, which affects approximately 70,000 individuals worldwide. New therapeutic developments over the last few decades have resulted in a significant increase in survival, with the median predicted survival now reaching the late thirties and more and more CF patients living well into adulthood. However, with this advent of new therapies and the associated increase in survival, new challenges in CF care have also emerged. Two of these challenges, i.e. chronic methicillin-resistant Staphylococcus aureus lung infection and patient adherence to very complicated and time-consuming therapeutic regimens, are reviewed in detail here. In addition, the ultimate challenge of treating the underlying cause of CF by correcting the dysfunction of the CF transmembrane conductance regulator chloride channel is reviewed, as agents to correct channel function will likely significantly alter CF clinical outcomes and treatment approaches in the next decade., (© 2014 S. Karger AG, Basel.)

Cystic fibrosis is caused by dysfunction or deficiency of the cystic fibrosis transmembrane conductance regulator (CFTR) protein, an epithelial chloride channel that has a key role in maintaining homoeostasis of the airway surface liquid layer in the lungs. More than 1900 CFTR mutations that might result in a disease phenotype have been identified; these can be grouped into classes on the basis of their effect on CFTR protein production, trafficking, function, and stability. In the past 2 years, landmark clinical trials have shown that correction of CFTR function leads to substantial clinical benefit for individuals with cystic fibrosis. These findings are ushering in a new era of cystic fibrosis treatments designed to correct the underlying CFTR defect caused by different mutation classes. With analysis of continuing trials and available patient registries, here we assess mutation types and the number and geographical distribution of patients who are likely to benefit from CFTR-correcting treatment., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

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.

For effective airway gene therapy of cystic fibrosis (CF), inhaled gene carriers must first penetrate the hyperviscoelastic sputum covering the epithelium. Whether clinically studied gene carriers can penetrate CF sputum remains unknown. Here, we measured the diffusion of a clinically tested nonviral gene carrier, composed of poly-l-lysine conjugated with a 10 kDa polyethylene glycol segment (CK(30)PEG(10k)). We found that CK(30)PEG(10k)/DNA nanoparticles were trapped in CF sputum. To improve gene carrier diffusion across sputum, we tested adjuvant regimens consisting of N-acetylcysteine (NAC), recombinant human DNase (rhDNase) or NAC together with rhDNase. While rhDNase alone did not enhance gene carrier diffusion, NAC and NAC + rhDNase increased average effective diffusivities by 6-fold and 13-fold, respectively, leading to markedly greater fractions of gene carriers that may penetrate sputum layers. We further tested the adjuvant effects of NAC in the airways of mice with Pseudomonas aeruginosa lipopolysaccharide (LPS)-induced mucus hypersecretion. Intranasal dosing of NAC prior to CK(30)PEG(10k)/DNA nanoparticles enhanced gene expression by up to ~12-fold compared to saline control, reaching levels observed in the lungs of mice without LPS challenge. Our findings suggest that a promising synthetic nanoparticle gene carrier may transfer genes substantially more effectively to lungs of CF patients if administered following adjuvant mucolytic therapy with NAC or NAC + rhDNase.

Background: Vitamin D deficiency is common in patients with cystic fibrosis (CF), and guidelines recommend 25-hydroxyvitamin D (25OHD) levels ≥ 30 ng/mL. This threshold was selected because serum parathyroid hormone (PTH) rises in healthy individuals when the 25OHD level falls below 30 ng/mL. PTH levels > 50 pg/mL are associated with an increased risk of bone loss. However, the relationship between 25OHD and PTH has not been studied in CF. We sought to determine the appropriate goal 25OHD level in patients with CF by identifying the level below which the risk of PTH > 50 pg/mL begins to increase., Methods: Levels of 25OHD and PTH in 216 individuals with CF were collected prospectively. Individuals with 25OHD < 30 ng/mL were treated with vitamin D2, and levels were reevaluated., Results: Mean 25OHD level was 25.7 ± 12.4 ng/mL, and mean PTH level was 46.7 ± 25.9 pg/mL. In 63% of individuals, 25OHD level was < 30 ng/mL, and in 38.0% it was ≤ 20 ng/mL. Low 25OHD levels were significantly associated with elevated PTH levels, with a mean PTH of 53.1 ± 29.8 pg/mL for 25OHD level 0 to 19 ng/mL; 51.1 ± 30.7 pg/mL for 25OHD level 20 to 29 ng/mL; 38.4 ± 16.4 pg/mL for 25OHD level 30 to 39 ng/mL; and 37.2 ± 16.4 pg/mL for 25OHD level ≥ 40 ng/mL (P = .006). We assessed the sensitivity of different 25OHD thresholds to identify individuals meeting the goal of a PTH level < 50 pg/mL to reduce the risk of bone loss. To obtain 90% sensitivity, a 25OHD level ≥ 35 ng/mL was required. Strikingly, 23% of individuals with 25OHD levels 30 to 34 ng/mL still had a PTH level > 50 pg/mL. This decreased to 14% for 25OHD level ≥ 35 ng/mL., Conclusions: Inadequate serum 25OHD levels are common in adults with CF and are associated with elevated PTH levels. Aiming to maintain 25-OHD levels ≥ 35 ng/mL in individuals with CF decreases the risk of having a PTH level associated with secondary hyperparathyroidism and bone loss.

Background: This study examined the relationship of medication adherence to frequency of pulmonary exacerbation and rate of decline in FEV(1)% predicted (FEV(1))., Methods: 95 CF patients aged 6 years or older and prescribed a pulmonary medication, were enrolled in a longitudinal retrospective review of medication adherence and health outcomes (the occurrence and frequency of intravenous (IV) antibiotic treatments and FEV(1)) over 12-months. Pharmacy refill records were used to calculate a medication possession ratio (MPR)., Results: Composite MPR predicted the occurrence of at least one pulmonary exacerbation requiring a course of IV antibiotics (IRR=2.34, p=0.05), but not the frequency of exacerbations, after controlling for gender, baseline FEV(1,) and regimen complexity. Composite MPR predicted baseline FEV(1) (estimate=29.81, p=.007), but not decline in FEV(1)., Conclusions: These results demonstrate a significant relation between medication adherence and IV antibiotics in CF patients, highlighting the importance of addressing adherence during clinic visits to improve health outcomes., (Copyright © 2011 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.)

Aims: Sputum poses a critical diffusional barrier that strongly limits the efficacy of drug and gene carriers in the airways of individuals with cystic fibrosis (CF). Previous attempts to enhance particle penetration of CF sputum have focused on either reducing its barrier properties via mucolytics, or decreasing particle adhesion to sputum constituents by coating the particle surface with non-mucoadhesive polymers, including polyethylene glycol (PEG). Neither approach has enabled particles to penetrate expectorated sputum at rates previously observed for non-mucoadhesive nanoparticles in human cervicovaginal mucus. Here, we sought to investigate whether a common mucolytic, N-acetyl cysteine (NAC), in combination with dense PEG coatings on particles, can synergistically enhance particle penetration across fresh undiluted CF sputum., Materials & Methods: We used high-resolution multiple particle tracking to measure the diffusion of uncoated and PEG-coated nanoparticles in native and NAC-treated CF sputum., Results: We discovered that 200 nm particles, if densely coated with PEG, were able to penetrate CF sputum pretreated with NAC with average speeds approaching their theoretical speeds in water. Based on the rapid penetration of PEG-coated particles in NAC-treated sputum, we determined that the average spacing between sputum mesh elements was increased from 145 ± 50 nm to 230 ± 50 nm upon NAC treatment. Mathematical models based on particle transport rates suggest as much as 75 and 30% of 200 and 500 nm PEG-coated particles, respectively, may penetrate a physiologically thick NAC-treated CF sputum layer within 20 min. Uncoated particles were trapped in CF sputum pretreated with NAC nearly to the same extent as in native sputum, suggesting that NAC treatment alone offered little improvement to particle penetration., Conclusion: NAC facilitated rapid diffusion of PEG-coated, muco-inert nanoparticles in CF sputum. Our results provide a promising strategy to improve drug and gene carrier penetration in CF sputum, offering hope for improved therapies for CF.

Norwalk virus and human papilloma virus, two viruses that infect humans at mucosal surfaces, have been found capable of rapidly penetrating human mucus secretions. Viral vectors for gene therapy of Cystic Fibrosis (CF) must similarly penetrate purulent lung airway mucus (sputum) to deliver DNA to airway epithelial cells. However, surprisingly little is known about the rates at which gene delivery vehicles penetrate sputum, including viral vectors used in clinical trials for CF gene therapy. We find that sputum spontaneously expectorated by CF patients efficiently traps two viral vectors commonly used in CF gene therapy trials, adenovirus (d∼80 nm) and adeno-associated virus (AAV serotype 5; d∼20 nm), leading to average effective diffusivities that are ∼3,000-fold and 12,000-fold slower than their theoretical speeds in water, respectively. Both viral vectors are slowed by adhesion, as engineered muco-inert nanoparticles with diameters as large as 200 nm penetrate the same sputum samples at rates only ∼40-fold reduced compared to in pure water. A limited fraction of AAV exhibit sufficiently fast mobility to penetrate physiologically thick sputum layers, likely because of the lower viscous drag and smaller surface area for adhesion to sputum constituents. Nevertheless, poor penetration of CF sputum is likely a major contributor to the ineffectiveness of viral vector based gene therapy in the lungs of CF patients observed to date.

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)., Results: At day 28, in the group of subjects who received 150 mg of VX-770, the median change in the nasal potential difference (in response to the administration of a chloride-free isoproterenol solution) from baseline was -3.5 mV (range, -8.3 to 0.5; P=0.02 for the within-subject comparison, P=0.13 vs. placebo), and the median change in the level of sweat chloride was -59.5 mmol per liter (range, -66.0 to -19.0; P=0.008 within-subject, P=0.02 vs. placebo). The median change from baseline in the percent of predicted forced expiratory volume in 1 second was 8.7% (range, 2.3 to 31.3; P=0.008 for the within-subject comparison, P=0.56 vs. placebo). None of the subjects withdrew from the study. Six severe adverse events occurred in two subjects (diffuse macular rash in one subject and five incidents of elevated blood and urine glucose levels in one subject with diabetes). All severe adverse events resolved without the discontinuation of VX-770., Conclusions: This study to evaluate the safety and adverse-event profile of VX-770 showed that VX-770 was associated with within-subject improvements in CFTR and lung function. These findings provide support for further studies of pharmacologic potentiation of CFTR as a means to treat cystic fibrosis. (Funded by Vertex Pharmaceuticals and others; ClinicalTrials.gov number, NCT00457821.).

Background: As more patients with cystic fibrosis (CF) reach adulthood and participate in age-appropriate activities (e.g. employment, dating), disclosure of medical status becomes more important. This study assessed rates of disclosure and its perceived impact on relationships using the Adult Data for Understanding Lifestyle and Transitions (ADULT) online survey., Methods: Adults with CF participated in the survey via the United States national network of CF Centers. Descriptive and inferential statistics were utilized., Results: Participants (n = 865) were more likely to disclose to relatives (94%) and close friends (81%) than to dating partners (73%), bosses/supervisors/teachers (51%) or co-workers (39%). Respondents generally reported a neutral/positive effect on relationships following disclosure. Negative effects of disclosure were infrequent, but more likely with dating partners or bosses/supervisors/teachers. Results also indicated that disclosure may be influenced by severity of lung disease and gender, with those having normal/mild lung disease less likely to disclose their diagnosis to both co-workers (p < 0.01) and bosses/supervisors/teachers (p < 0.01), and women being more likely to disclose to close friends (p < 0.0001) and dating partners (p < 0.05) than men., Conclusions: Most adults with CF disclosed their disease to relatives and close friends. Individuals with severe CF lung disease were more likely to disclose their diagnosis to coworkers and supervisors/teachers. It may be helpful to provide support for disclosure of disease in situations such as employment and dating.

Context: The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in the respiratory tract of individuals with cystic fibrosis (CF) has increased dramatically; however, its impact on outcomes in CF is unclear. Because the time between infection with bacteria in CF and death can be decades, observational studies with long periods of follow-up are well suited to address the current gap in knowledge., Objective: To determine whether isolation of MRSA from the respiratory tract of CF patients is associated with worse survival compared with patients who never have a culture positive for MRSA., Design, Setting, and Participants: Cohort study of 19,833 CF patients aged 6 to 45 years seen at centers accredited by the Cystic Fibrosis Foundation in the United States. Patients entered between January 1996 and December 2006 and were followed up through December 2008. Cox regression models with time-varying covariates were used to compare survival between CF patients with and without respiratory tract MRSA., Main Outcome Measure: Time from age at entry until age at death from any cause., Results: In 137,819 patient-years of observation (median, 7.3 years/patient), 2537 CF patients died and 5759 patients had MRSA detected. The mortality rate was 18.3 deaths (95% confidence interval [CI], 17.5-19.1) per 1000 patient-years in patients without MRSA and 27.7 deaths (95% CI, 25.3-30.4) per 1000 patient-years in those with MRSA. Among those with MRSA, the attributable risk percentage of death associated with MRSA was 34.0% (95% CI, 26.7%-40.4%). The unadjusted hazard ratio associated with MRSA was 1.47 (95% CI, 1.32-1.62). After adjustment for time-varying covariates associated with severity of illness, MRSA remained associated with a higher risk of death (1.27; 95% CI, 1.11-1.45)., Conclusion: Detection of MRSA in the respiratory tract of CF patients was associated with worse survival.

Background: Filamentous fungi are frequently recovered from respiratory cultures of individuals with CF., Methods: A CF cohort database was utilized to determine filamentous fungal prevalence and risk factors., Results: The prevalence of filamentous fungal isolation increased from 2.0% in 1997 to 28.7% in 2007. The odds of isolating filamentous fungi during a quarter was greater in CF adults [p<0.001], during chronic oral antibiotic use [p=0.002] and increased with each 10% drop in FEV(1) percent predicted [p=0.005], while inhaled corticosteroids surprisingly decreased the likelihood [p=0.012]. The direction of these effects persisted after excluding individuals with ABPA. A sub-analysis determined older age [p=0.019] and use of inhaled antibiotics [p=0.011] were independent risk factors for onset of fungal colonization., Conclusions: This study suggests that isolation of filamentous fungi in CF at JHH has increased and risk factors include older age, decreased lung function, and chronic oral antibiotics., (Copyright (c) 2009 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.)

Highly viscoelastic and adhesive sputum has precluded efficient nanoparticle-based drug and gene delivery to the lungs of patients with cystic fibrosis (CF). We sought to determine whether nanoparticles coated with non-mucoadhesive polymers could penetrate CF sputum, and to use these "muco-inert particles" (MIPs) as non-destructive nanoprobes to characterize the sputum microstructure. Particles as large as 200 nm in diameter that were densely coated with low MW polyethylene glycol (PEG) moved through undiluted CF sputum with average speeds up to 90-fold faster than similarly-sized uncoated particles. On the other hand, the transport of both coated and uncoated 500 nm particles was strongly hindered. The local viscosity of sputum, encountered by the fastest 10% of 200 nm MIPs, was only 5-fold higher than that of water, whereas the bulk viscosity was 10,000-fold higher at low shear rates. Using measured transport rates of various sized MIPs combined with an obstruction-scaling model, we determined that the average 3D mesh spacing of CF sputum is approximately 140+/-50 nm (range: 60-300 nm). Taken together, these results demonstrate that nanoparticles up to 200 nm in diameter that do not adhere to CF sputum can move rapidly through this critical barrier by accessing pores that are filled with a low viscosity fluid. The results also offer hope that desperately needed sputum-penetrating drug- and gene-carrier nanoparticles can be developed for CF.

Rationale: The prevalence in cystic fibrosis (CF) of respiratory cultures with methicillin-resistant Staphylococcus aureus (MRSA) has dramatically increased over the last 10 years, but the effect of MRSA on FEV(1) decline in CF is unknown., Objectives: To determine the association between MRSA respiratory infection and FEV(1) decline in children and adults with CF., Methods: This was a 10-year cohort study using the Cystic Fibrosis Foundation patient registry from 1996-2005. We studied individuals who developed new MRSA respiratory tract infection. Repeated-measures regression was used to assess the association between MRSA and FEV(1) decline, adjusted for confounders, in individuals aged 8-21 years and adults (aged 22-45 yr). Two different statistical models were used to assess robustness of results., Measurements and Main Results: The study cohort included 17,357 patients with an average follow-up of 5.3 years. During the study period, 1,732 individuals developed new persistent MRSA infection (> or =3 MRSA cultures; average, 6.8 positive cultures) and were subsequently followed for an average of 3.5 years. Even after adjustment for confounders, rate of FEV(1) decline in individuals aged 8-21 years with persistent MRSA was more rapid in both statistical models. Their average FEV(1) decline of 2.06% predicted/year was 43% more rapid than the 1.44% predicted/year in those without MRSA (difference, -0.62% predicted/yr; 95% confidence interval, -0.70 to -0.54; P < 0.001). Effect of MRSA on FEV(1) decline in adults was not clinically significant., Conclusions: Persistent infection with MRSA in individuals with CF between the ages of 8 and 21 years is associated with a more rapid rate of decline in lung function.

Objectives: More than 500,000 adolescents with special health care needs age into adulthood each year in the United States, and there is growing recognition of the need for support of their transition to adult-oriented health care. Because of improved survival, cystic fibrosis has experienced this increasing transition need, and cystic fibrosis policy leaders responded by mandating the transition of adults with cystic fibrosis to adult-focused cystic fibrosis care programs by 2000. The primary objective of this study was to characterize in detail recent transition practices at US cystic fibrosis programs, to identify areas for improvement and to serve as a model for other diseases. A secondary objective of this study was to develop and validate a survey for formal assessment of transition practices., Methods: A 105-question survey on key aspects of transition was administered to cystic fibrosis care team members from all 195 US Cystic Fibrosis Care programs. Rates of adherence to recommended components of transition care were measured., Results: A total of 448 surveys were obtained from 170 (87%) of 195 cystic fibrosis programs. Although transfer of care occurs at a median age of 19 years, initial discussion of transition does not occur until a median age of 17 years, limiting time to foster self-care skills. Only half of programs consistently perform a transition readiness assessment, 28% of centers offer visits focused on transition, and <10% have a written list of desirable self-management skills., Conclusions: There is significant variability in transition support provided to young adults with cystic fibrosis, but there are simple steps that may lead to more consistent delivery of transition services. Methods of assessment and lessons learned from transitioning young adults at US cystic fibrosis programs may serve to improve transition for individuals with other childhood diseases.

Cystic fibrosis is a multisystem disease characterized primarily by chronic pulmonary infection and bronchiectasis, pancreatic exocrine impairment, and elevated sweat chloride. In the last 4 decades, new treatment strategies and aggressive nutritional management have resulted in a significant increase in expected survival, with median predicted survival in cystic fibrosis now to older than 35 years. This increase in predicted survival has also been aided by a greater appreciation of the potential variability in the presentation and severity of cystic fibrosis, resulting in identification of a growing number of mild cases. As it is estimated that within the next decade more than half of all individuals with cystic fibrosis will be aged 18 years or older, adult medicine caregivers are increasingly likely to encounter patients with cystic fibrosis and be exposed to their unique medical management.

Context: Patients with Albright hereditary osteodystrophy (AHO) have defects in stimulatory G protein signaling due to loss of function mutations in GNAS. The mechanism by which these mutations lead to the AHO phenotype has been difficult to establish due to the inaccessibility of the affected tissues., Objective: The objective of the study was to gain insight into the downstream consequences of abnormal stimulatory G protein signaling in human epithelial tissues., Patients and Design: We assessed transcription of GNAS and Gsalpha-stimulated activation of the cystic fibrosis transmembrane conductance regulator (CFTR) in AHO patients, compared with normal controls and patients with cystic fibrosis., Main Outcome Measures: Relative expression of Gsalpha transcripts from each parental GNAS allele and cAMP measurements from nasal epithelial cells were compared among normal controls and AHO patients. In vivo measurements of CFTR function, pulmonary function, and pancreatic function were assessed in AHO patients., Results: GNAS was expressed equally from each allele in normals and two of five AHO patients. cAMP generation was significantly reduced in nasal respiratory epithelial cells from AHO patients, compared with normal controls (0.4 vs. 0.6, P = 0.0008). Activation of CFTR in vivo in nasal (P = 0.0065) and sweat gland epithelia (P = 0.01) of AHO patients was significantly reduced from normal. In three patients, the reduction in activity was comparable with patients with cystic fibrosis due to mutations in CFTR. Yet no AHO patients had pulmonary or pancreatic disease consistent with cystic fibrosis., Conclusions: In humans, haploinsufficiency of GNAS causes a significant reduction in the activation of the downstream target, CFTR, in vivo.

Background: Infection with multiple antibiotic-resistant Pseudomonas aeruginosa (MARPA) in individuals with cystic fibrosis (CF) has caused much concern among caregivers, yet little is known about the risks associated with acquiring resistance. The main objective of the study was to estimate the incidence and identify risk factors for the acquisition of MARPA among individuals with CF., Methods: Five-year cohort study of individuals followed in the Cystic Fibrosis Foundation Registry from 1998 through 2002., Results: Demographics, anthropometrics, spirometry, respiratory culture results, comorbidities, antibiotic usage, and hospitalizations were collected. Of the 4,293 patients with P aeruginosa infection during the study period, MARPA developed in 341. The overall incidence of MARPA was 1.8%/yr. Independent risk factors for MARPA included CF-related diabetes mellitus (hazard ratio [HR], 1.64; 95% confidence interval [CI], 1.11 to 2.43), long-term inhaled tobramycin usage (HR, 2.08; 95% CI, 1.56 to 2.77), and care at a CF center with a baseline MARPA prevalence in the top quartile (HR, 2.00; 95% CI, 1.31 to 3.04). Frequent courses of IV antibiotics and repeated hospitalizations were also found to independently increase the risk for MARPA., Conclusions: Infection with MARPA is common among patients with CF. Diabetes, long-term inhaled tobramycin usage, and frequent acute pulmonary exacerbations requiring hospitalization or IV antibiotics increase the risk for MARPA. Receiving CF care at a center with a high prevalence of resistant Pseudomonas also increases the risk for MARPA in patients with CF. Further study is needed to investigate the mechanisms of acquiring resistant strains and the clinical impact of MARPA on CF outcomes.

Background: More than 40% of people born with cystic fibrosis (CF) now reach adulthood. Greater attention is being focused on improving their health-related quality of life (HRQoL). While markers of disease severity such as lung function are only modestly associated with HRQoL, in other chronic illnesses depression is an important correlate. The objective of this study was to evaluate the relationships among lung function (ie, FEV(1) percent predicted), depressive symptoms, and HRQoL among adults with CF., Methods: Seventy-six adults with CF completed a mail-based survey. The Beck Depression Inventory and the Cystic Fibrosis Questionnaire were used to assess depressive symptoms and HRQoL, respectively. Values for FEV(1) percent predicted were abstracted from the medical record., Results: Thirty percent of participants screened positive for depressive symptoms. Depressive symptoms and lung function were inversely correlated (rho = -0.25; p < .05). Correlations between depressive symptoms and HRQoL were maintained after stratifying by lung function. In the absence of depressive symptoms, those patients with good lung function (ie, FEV(1), > 70% predicted) reported better physical HRQoL than those with poor lung function. Participants with both depressive symptoms and poor lung function reported significantly worse HRQoL on all domains than participants without depressive symptoms regardless of lung function status., Conclusions: Depressive symptoms are prevalent among adults with CF and are associated with poorer HRQoL even after controlling for lung function. These results suggest that screening for and treating depression is important and may potentially improve HRQoL among patients with CF.

Background: Cystic fibrosis (CF) patients have enhanced renal clearance of aminoglycosides and several beta-lactams and require higher dosages. Levofloxacin is a fluoroquinolone with extensive renal elimination and enhanced penetration into lungs and Pseudomonas aeruginosa (PA) biofilms. We studied the preliminary pharmacokinetic and pharmacodynamic (PK/PD) relationship of levofloxacin in CF., Methods: Twelve patients at least 18 years old with a mild-to-moderate pulmonary exacerbation and fluoroquinolone-sensitive PA colonization received oral levofloxacin, 500 mg qd, for 14 days. Steady-state serum concentrations were collected after 3 to 7 days, and sputum samples for PA densities were collected before and after levofloxacin. PK/PD relationships for reducing PA sputum densities were evaluated., Results: When compared to published data on non-CF patients, CF patients had similar area under the curve for 24 h (AUC(24)), total clearance, volume of distribution, maximum serum concentration (Cpmax), and elimination half-life: mean, 7.33 microg x h/mL/kg (SD, 1.70); 2.43 mL/min/kg (SD, 0.74); 1.33 L/kg (SD, 0.37); 7.06 microg/mL (SD, 2.35); and 6.44 h (SD, 1.1), respectively. Time to reach maximum serum concentration (Tmax) in CF was longer: mean, 2.20 h (SD, 0.99) vs 1.1 h (SD, 0.4) [p < 0.01]. Preliminary PK/PD analysis failed to demonstrate trends for decreasing PA sputum densities with increasing Cpmax/minimum inhibitory concentration (MIC) ratio and AUC(24)/MIC ratio., Conclusion: CF levofloxacin pharmacokinetics corrected for body weight are similar to non-CF, except for Tmax. Standard levofloxacin dosing (especially monotherapy) is unlikely to produce maximum therapeutic effectiveness. Additional levofloxacin studies in CF are necessary to evaluate its sputum concentrations; the benefits of higher daily dosages (>/= 750 mg); and establish PK/PD targets for managing PA pulmonary infections.

Background: Patients with cystic fibrosis with the same mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene differ widely in survival suggesting other factors have a substantial role in mortality., Objective: To determine if the genotype distribution of variants in three putative cystic fibrosis modifier genes (tumour necrosis factor alpha (TNFalpha), transforming growth factor beta1 (TGFbeta1) or mannose-binding lectin (MBL2)) differed among patients with cystic fibrosis grouped according to age and survival status., Methods: Genotypes of four variants (TNFalpha-238, TNFalpha-308, TGFbeta1-509 and MBL2 O) were determined in three groups of Caucasians from a single medical centre: 101 children with cystic fibrosis (aged <17 years; mean age 9.4 years), 115 adults with cystic fibrosis (aged > or =17 years; mean age 30.8 years) and 38 non-surviving adults with cystic fibrosis (21 deceased and 17 lung transplant after 17 years of age). Genotypes of 127 healthy Caucasians in the same geographical region were used as controls. Kaplan-Meier and Cox hazard regression were used to evaluate the genotype effect on cumulative survival., Results: Genotype frequencies among adults and children with cystic fibrosis differed for TNFalpha-238 (G/G vs G/A; p = 0.022) and MBL2 (A/A vs O/O; p = 0.016). When adults with cystic fibrosis were compared to non-surviving adults with cystic fibrosis, genotype frequencies of both genes differed (TNFalpha-238G/G vs G/A; p = 0.0015 and MBL2: A/A vs O/O; p = 0.009). The hazard ratio for TNFalpha-238G/G vs G/A was 0.25 (95% CI 0.06 to 1.0, p = 0.04) and for MBL2 O/O vs A/A or A/O was 2.5 (95% CI 1.3 to 4.9, p = 0.007)., Conclusions: TNFalpha-238 G/A and MBL2 O/O genotypes appear to be genetic modifiers of survival of cystic fibrosis.

Even in patients with cystic fibrosis (CF) with identical CFTR genotypes, there is a wide range in the severity of lung disease, with some individuals facing death or lung transplantation early in life and others demonstrating mild lung disease well into adulthood. Although numerous environmental factors have been identified that influence CF pulmonary phenotype, there is now growing evidence that polymorphic variants in genes besides CFTR play an important role in determining severity of CF lung disease. This article reviews the most recent findings regarding genetic modifiers in CF and also discusses in detail the strategies currently being used to identify novel modifiers of CF pulmonary phenotype. These include single- and multicenter studies, twin and sib studies, microarray approaches, and whole genome association studies.

Purpose of Review: The high prevalence of decreased bone density in adults with cystic fibrosis is now well recognized, and guidelines for screening and treatment of cystic fibrosis-related bone disease have recently been published. This review summarizes the current best practices for optimizing bone health in cystic fibrosis and highlight recent findings that provide insight into the etiology of cystic fibrosis-related bone disease., Recent Findings: Recent research suggests that cystic fibrosis-related bone disease actually starts during childhood, when individuals with cystic fibrosis fail to demonstrate normal bone calcium accretion. The failure to reach peak bone mass is made worse by increased osteoclast activity and bone resorption. This combination results in decreased bone density and an increased risk of fracture. Recent clinical studies suggest that multiple contributing factors need to be addressed in cystic fibrosis to optimize bone health: malnutrition, vitamin and mineral malabsorption, recurrent infections, inadequate sex hormones, and lack of exercise. Oral bisphosphonates have been demonstrated to be effective in cystic fibrosis and should be used when osteoporosis or progressive osteopenia is present., Summary: Research suggests cystic fibrosis-related bone disease actually begins during childhood, and guidelines now exist to aid in identifying and treating those with decreased bone density.

Despite having identical cystic fibrosis transmembrane conductance regulator genotypes, individuals with DeltaF508 homozygous cystic fibrosis (CF) demonstrate significant variability in severity of pulmonary disease. This investigation used high-density oligonucleotide microarray analysis of nasal respiratory epithelium to investigate the molecular basis of phenotypic differences in CF by (1) identifying differences in gene expression between DeltaF508 homozygotes in the most severe 20th percentile of lung disease by forced expiratory volume in 1 s and those in the most mild 20th percentile of lung disease and (2) identifying differences in gene expression between DeltaF508 homozygotes and age-matched non-CF control subjects. Microarray results from 23 participants (12 CF, 11 non-CF) met the strict quality control guidelines and were used for final data analysis. A total of 652 of the 11,867 genes identified as present in 75% of the samples were significantly differentially expressed in one of the three disease phenotypes: 30 in non-CF, 53 in mild CF, and 569 in severe CF. An analysis of genes differentially expressed by severity of CF lung disease demonstrated significant upregulation in severe CF of genes involved in protein ubiquination (P < 0.04), mitochondrial oxidoreductase activity (P < 0.01), and lipid metabolism (P < 0.03). Analysis of genes with decreased expression in patients with CF compared with control subjects demonstrated significant downregulation of genes involved in airway defense (P < 0.047) and protein metabolism (P < 0.048). This study suggests that differences in CF lung phenotype are associated with differences in expression of genes involving airway defense, protein ubiquination, and mitochondrial oxidoreductase activity and identifies specific new candidate modifiers of the CF phenotype.

Background: Although Pseudomonas aeruginosa is the most common bacterial infection in adults with cystic fibrosis and frequently develops resistance to multiple classes of antibiotics, it has not been determined whether patients with multiple antibiotic-resistant Pseudomonas aeruginosa have worse clinical outcomes than patients with more susceptible strains., Objectives: This study assessed the impact of multiply-resistant P. aeruginosa on lung function, hospitalizations, antibiotic use, lung transplantation and survival in adults with cystic fibrosis., Methods: In a cohort study at a university-based adult cystic fibrosis program, 75 consecutive adult cystic fibrosis patients who had P. aeruginosa isolated from sputum cultures were studied over a 4-year period. Outcomes included decline in FEV1, clinic visits, hospitalizations, courses and days of intravenous antibiotics, and lung transplantation. Multiple linear and Poisson regression for repeated measures were used to assess the outcomes., Results: In comparison to patients with susceptible strains, patients with resistant P. aeruginosa had more severe baseline lung disease, more rapid decline in FEV1 (160 ml/year, p = 0.003) and were significantly more likely to undergo lung transplantation (17.6 vs. 0%, p = 0.005)., Conclusions: Infection with multiple-antibiotic-resistant P. aeruginosa is associated with accelerated progression of cystic fibrosis, and has important implications for infection control strategies, antibiotic use and lung transplantation., (Copyright 2006 S. Karger AG, Basel.)

Rationale: Treatment guidelines for vitamin D monitoring and supplementation in cystic fibrosis (CF) have recently been developed and published by a consensus committee, but have not been prospectively tested., Objectives: To use these guidelines to determine the percentage of adults with CF requiring vitamin D repletion therapy and to evaluate the effectiveness of the currently recommended high-dose oral ergocalciferol repletion protocol., Methods: Prospective study of clinical outcomes after therapy with the recommended vitamin D repletion algorithm., Results: Of 134 adults with CF, 109 (81.3%) were found to have 25-hydroxyvitamin D (25-OHD) levels below the recommended 30 ng/ml. Sixty-six of these adults completed the recommended course of 400,000 IU of oral ergocalciferol over 2 months, and only five (8%) responded with correction of their serum 25-OHD to the goal of 30 ng/ml or greater (mean change, +0.3 ng/ml; from 18.8 to 19.1 ng/ml). In the 33 adults with CF who also completed the recommended second course of 800,000 IU of ergocalciferol over 2 months, none demonstrated correction of their deficiency (mean change, -1.2 ng/ml)., Conclusion: The results of this study demonstrate that a majority of adults with CF have serum 25-OHD levels below 30 ng/ml, and the currently recommended ergocalciferol repletion regimen often does not fully correct vitamin D deficiency and may need to be revised to include even higher dosing of ergocalciferol. Further work is needed to establish the ideal 25-OHD level for maximizing calcium absorption and bone health in CF.