Diana Bilton

Repeated nebulisation of non-viral CFTR gene therapy in patients with cystic fibrosis: a randomised, double-blind, placebo-controlled, phase 2b trial

Summary Background Lung delivery of plasmid DNA encoding the CFTR gene complexed with a cationic liposome is a potential treatment option for patients with cystic fibrosis. We aimed to assess the efficacy of non-viral CFTR gene therapy in patients with cystic fibrosis. Methods We did this randomised, double-blind, placebo-controlled, phase 2b trial in two cystic fibrosis centres with patients recruited from 18 sites in the UK. Patients (aged ≥12 years) with a forced expiratory volume in 1 s (FEV1) of 50–90% predicted and any combination of CFTR mutations, were randomly assigned, via a computer-based randomisation system, to receive 5 mL of either nebulised pGM169/GL67A gene–liposome complex or 0·9% saline (placebo) every 28 days (plus or minus 5 days) for 1 year. Randomisation was stratified by % predicted FEV1 (<70 vs ≥70%), age (<18 vs ≥18 years), inclusion in the mechanistic substudy, and dosing site (London or Edinburgh). Participants and investigators were masked to treatment allocation. The primary endpoint was the relative change in % predicted FEV1. The primary analysis was per protocol. This trial is registered with ClinicalTrials.gov, number NCT01621867. Findings Between June 12, 2012, and June 24, 2013, we randomly assigned 140 patients to receive placebo (n=62) or pGM169/GL67A (n=78), of whom 116 (83%) patients comprised the per-protocol population. We noted a significant, albeit modest, treatment effect in the pGM169/GL67A group versus placebo at 12 months follow-up (3·7%, 95% CI 0·1–7·3; p=0·046). This outcome was associated with a stabilisation of lung function in the pGM169/GL67A group compared with a decline in the placebo group. We recorded no significant difference in treatment-attributable adverse events between groups. Interpretation Monthly application of the pGM169/GL67A gene therapy formulation was associated with a significant, albeit modest, benefit in FEV1 compared with placebo at 1 year, indicating a stabilisation of lung function in the treatment group. Further improvements in efficacy and consistency of response to the current formulation are needed before gene therapy is suitable for clinical care; however, our findings should also encourage the rapid introduction of more potent gene transfer vectors into early phase trials. Funding Medical Research Council/National Institute for Health Research Efficacy and Mechanism Evaluation Programme.

US Cystic Fibrosis Foundation and European Cystic Fibrosis Society consensus recommendations for the management of non-tuberculous mycobacteria in individuals with cystic fibrosis: executive summary

Non-tuberculous mycobacteria (NTM) are ubiquitous environmental organisms that can cause chronic pulmonary infection, particularly in individuals with pre-existing inflammatory lung disease, such as cystic fibrosis (CF). Pulmonary disease (PD) caused by NTM has emerged as a major threat to the health of individuals with CF, but remains difficult to diagnose and problematic to treat. In response to this challenge, the US Cystic Fibrosis Foundation (CFF) and the European Cystic Fibrosis Society (ECFS) convened a panel of 19 experts to develop consensus recommendations for the screening, investigation, diagnosis and management of NTM-PD in individuals with CF. PICO (population, intervention, comparison, outcome) methodology and systematic literature reviews were employed to inform draft recommendations, which were then modified to achieve consensus and subsequently circulated for public consultation within the USA and European CF communities. We have thus generated a series of pragmatic, evidence-based recommendations as an initial step in optimising management for this challenging condition.

Phase 3 Randomized Study of the Efficacy and Safety of Inhaled Dry Powder Mannitol for the Symptomatic Treatment of Non-Cystic Fibrosis Bronchiectasis

BACKGROUNDnInhaled dry powder mannitol enhanced mucus clearance and improved quality of life over 2 weeks in non-cystic fibrosis bronchiectasis. This studys objective was to investigate the efficacy and safety of dry powder mannitol over 12 weeks.nnnMETHODSnPatients with bronchiectasis confirmed by high-resolution CT (HRCT) scan, aged 15 to 80 years, with FEV1≥50% predicted and ≥1 L participated in a randomized, placebo-controlled, double-blind study. Patients with a negative mannitol provocation test were randomized to inhale 320 mg mannitol (n=231) or placebo (n=112) bid for 12 weeks. To further assess safety, the same mannitol dose/frequency was administered to a patient subset in an open-label extension over 52 weeks. Primary end points were changes from baseline at 12 weeks in 24-h sputum weight and St. Georges Respiratory Questionnaire (SGRQ) score.nnnRESULTSnThere was a significant difference of 4.3 g in terms of change in sputum weight over 12 weeks (95% CI, 1.64-7.00; P=.002) between mannitol and placebo; however, this was largely driven by a decrease in sputum weight in the placebo group. This was associated, in turn, with more antibiotic use in the placebo group (50 of 112 [45%]) than in the inhaled mannitol group (85 of 231 [37%]). There was no statistical difference between the groups (P=.304) in total SGRQ score (mannitol, -3.4 points [95% CI, -4.81 to -1.94] vs placebo, -2.1 points [95% CI, -4.12 to -0.09]). In a subgroup study (n=82), patients receiving mannitol showed less small airway mucus plugging on HRCT scan at 12 weeks compared with patients receiving placebo (P=.048). Compliance rates were high, and mannitol was well tolerated with adverse events similar to those of placebo.nnnCONCLUSIONnBecause the difference in sputum weights appears to be associated with increased antibiotic use in the placebo group, a larger controlled study is now required to investigate the long-term mannitol effect on pulmonary exacerbations and antibiotic use.nnnTRIAL REGISTRYnClinicalTrials.gov; No.: NCT0027753; URL: www.clinicaltrials.gov.

Children and young adults with CF in the USA have better lung function compared with the UK

Background People with cystic fibrosis (CF) are managed differently in the USA and UK providing an opportunity to learn from differences in practice patterns. Objectives To compare cross-sectional demographics, practice patterns and clinical outcomes between US and UK CF patients. Methods This was a cross-sectional study using 2010 data from patients in the US Cystic Fibrosis Foundation and the UK Cystic Fibrosis patient registries. The a priori outcome measures of interest were lung function and nutritional status. Descriptive statistics and two sample comparisons were performed. Stratification and multivariable linear regression were used to adjust for confounding. Results The study cohort included 13u2005777 children and 11u2005058 adults from the USA and 3968 children and 3965 adults from the UK. In children, mean body mass index centiles were similar. Lung function (FEV1 and FVC% predicted) was significantly higher in US patients ages 6–25u2005years of age. In a regression model adjusted for only age, FEV1% predicted was on average 3.31% of predicted (95% CI 2.65 to 3.96) higher in the USA compared with the UK. When adjusted for age, age at diagnosis, gender, pancreatic insufficiency and genotype, FEV1% predicted was on average 3.03% of predicted (95% CI 2.37 to 3.69) higher in the USA compared with the UK These differences persisted despite adjustment for possible confounders. Hypertonic saline and dornase alfa were much more commonly prescribed in US children. Conclusions Children and young adults with CF have better lung function in the USA compared with the UK despite similar nutritional status.

A longitudinal study characterising a large adult primary ciliary dyskinesia population.

Primary ciliary dyskinesia (PCD) in adults has not been well described. In this retrospective observational study we aimed to characterise a large adult population and identify features associated with disease progression. We retrospectively analysed 151 adult patients at a single tertiary centre at baseline and longitudinally for a median of 7u2005years. We found significant variation in age at diagnosis (median 23.5u2005years; range <1–72u2005years). Older age at diagnosis was associated with impaired baseline forced expiratory volume in 1u2005s (FEV1) (r=u200a−0.30, p=0.01) and increased Pseudomonas aeruginosa colonisation (difference in medians 17u2005years (95% CI 4.5–20u2005years); p=0.002). Lung function decline was estimated at FEV1 decline of 0.49% predicted per year. Lung function decline was associated with ciliary ultrastructure, with microtubular defect patients having the greatest decline (p=0.04). High-resolution computed tomography (HRCT) scores of severity of bronchial wall dilatation (p<0.001) and extent of bronchiectasis (p=0.03) additionally showed evidence of modifying FEV1 decline with age. Our study reveals that a large proportion of adult PCD patients are diagnosed late, with impaired FEV1 and increased P. aeruginosa colonisation. Increased disease burden on HRCT and ciliary ultrastructure may predict progressive lung function decline. This study characterises a large adult PCD population, identifies features associated with disease progression and highlights the need for prospective trials to determine whether early diagnosis of high-risk subgroups alongside optimal management can modify disease progression. Increased severity on HRCT and ciliary ultrastructure predict progressive lung function decline in adults with PCD http://ow.ly/4ncpnD

HbA1c as a screening tool for cystic fibrosis related diabetes

AIMSnEarly diagnosis of cystic fibrosis (CF) related diabetes (CFRD) is important to improve outcomes. International guidelines recommend an oral glucose tolerance test (OGTT) for all CF patients aged ≥10 years - this approach is controversial. The aim of this study was to develop an effective screening tool and reduce the need for a universal OGTT.nnnMETHODSnAdult CF patients (without CFRD) attending an annual review assessment were recruited prospectively (March 2009-July 2012) into two sequential studies - a primary investigative study followed by validation study. All patients underwent an OGTT and were simultaneously screened by predetermined biochemical/clinical criteria to identify their risk of CFRD. A sensitivity/specificity analysis was performed using the World Health Organisation diabetes criteria as gold standard; modifications were made to improve the screening tools accuracy and determine the optimal screening thresholds. This was tested in the validation study.nnnRESULTSn429 patients (primary, n=94; validation, n=335: mean age=31.7 ± 10.4(SD), 43% female, 77% on pancreatic supplements). Primary study: in predicting a positive OGTT, the test sensitivity was 66.7% and specificity 60%. HbA1c was carried over to the validation study as it was the most discriminative (optimal threshold ≥5.8% (40 mmol/mol); receiver operating curve, ROC, score 0.60). Validation study: the number of patients with a normal, impaired and diabetic OGTT was 268(80%), 51(15.2%) and 16(4.8%), respectively. HbA1c provided a test sensitivity, specificity and ROC score of 93.8%, 53.0% and 0.73, respectively.nnnCONCLUSIONSnThe use of HbA1c ≥ 5.8%(40 mmol/mol) is an effective tool for CFRD screening and reduced the need for an OGTT by 50.7%.

Antipseudomonal Bacteriophage Reduces Infective Burden and Inflammatory Response in Murine Lung

ABSTRACT As antibiotic resistance increases, there is a need for new therapies to treat infection, particularly in cystic fibrosis (CF), where Pseudomonas aeruginosa is a ubiquitous pathogen associated with increased morbidity and mortality. Bacteriophages are an attractive alternative treatment, as they are specific to the target bacteria and have no documented side effects. The efficacy of phage cocktails was established in vitro. Two P. aeruginosa strains were taken forward into an acute murine infection model with bacteriophage administered either prophylactically, simultaneously, or postinfection. The infective burden and inflammation in bronchoalveolar lavage fluid (BALF) were assessed at various times. With low infective doses, both control mice and those undergoing simultaneous phage treatment cleared P. aeruginosa infection at 48 h, but there were fewer neutrophils in BALF of phage-treated mice (median, 73.2 × 104/ml [range, 35.2 to 102.1 × 104/ml] versus 174 × 104/ml [112.1 to 266.8 × 104/ml], P < 0.01 for the clinical strain; median, 122.1 × 104/ml [105.4 to 187.4 × 104/ml] versus 206 × 104/ml [160.1 to 331.6 × 104/ml], P < 0.01 for PAO1). With higher infective doses of PAO1, all phage-treated mice cleared P. aeruginosa infection at 24 h, whereas infection persisted in all control mice (median, 1,305 CFU/ml [range, 190 to 4,700 CFU/ml], P < 0.01). Bacteriophage also reduced CFU/ml in BALF when administered postinfection (24 h) and both CFU/ml and inflammatory cells in BALF when administered prophylactically. A reduction in soluble inflammatory cytokine levels in BALF was also demonstrated under different conditions. Bacteriophages are efficacious in reducing both the bacterial load and inflammation in a murine model of P. aeruginosa lung infection. This study provides proof of concept for future clinical trials in patients with CF.

Pseudomonas aeruginosa adaptation and diversification in the non-cystic fibrosis bronchiectasis lung

To characterise Pseudomonas aeruginosa populations during chronic lung infections of non-cystic fibrosis bronchiectasis patients, we used whole-genome sequencing to 1) assess the diversity of P. aeruginosa and the prevalence of multilineage infections; 2) seek evidence for cross-infection or common source acquisition; and 3) characterise P. aeruginosa adaptations. 189 isolates, obtained from the sputa of 91 patients attending 16 adult bronchiectasis centres in the UK, were whole-genome sequenced. Bronchiectasis isolates were representative of the wider P. aeruginosa population. Of 24 patients from whom multiple isolates were examined, there were seven examples of multilineage infections, probably arising from multiple infection events. The number of nucleotide variants between genomes of isolates from different patients was in some cases similar to the variations observed between isolates from individual patients, implying the possible occurrence of cross-infection or common source acquisition. Our data indicate that during infections of bronchiectasis patients, P. aeruginosa populations adapt by accumulating loss-of-function mutations, leading to changes in phenotypes including different modes of iron acquisition and variations in biofilm-associated polysaccharides. The within-population diversification suggests that larger scale longitudinal surveillance studies will be required to capture cross-infection or common source acquisition events at an early stage. P. aeruginosa co-infections occur in bronchiectasis; bacterial populations both adapt and diversify by mutation http://ow.ly/fMhj308zUv0

Longitudinal assessment of sputum microbiome by sequencing of the 16S rRNA gene in non-cystic fibrosis bronchiectasis patients.

Background Bronchiectasis is accompanied by chronic bronchial infection that may drive disease progression. However, the evidence base for antibiotic therapy is limited. DNA based methods offer better identification and quantification of microbial constituents of sputum than standard clinical culture and may help inform patient management strategies. Our study objective was to determine the longitudinal variability of the non-cystic fibrosis (CF) bronchiectasis microbiome in sputum with respect to clinical variables. Eighty-five patients with non-CF bronchiectasis and daily sputum production were recruited from outpatient clinics and followed for six months. Monthly sputum samples and clinical measurements were taken, together with additional samples during exacerbations. 16S rRNA gene sequencing of the sputum microbiota was successful for 381 samples from 76 patients and analysed in conjunction with clinical data. Results Microbial communities were highly individual in composition and stability, usually with limited diversity and often containing multiple pathogens. When compared to DNA sequencing, microbial culture had restricted sensitivity in identifying common pathogens such as Pseudomonas aeruginosa, Haemophilus influenzae, Moraxella catarrhalis. With some exceptions, community characteristics showed poor correlations with clinical features including underlying disease, antibiotic use and exacerbations, with the subject showing the strongest association with community structure. When present, the pathogens mucoid Pseudomonas aeruginosa and Haemophilus influenzae may also shape the structure of the rest of the microbial community. Conclusions The use of microbial community analysis of sputum added to information from microbial culture. A simple model of exacerbations driven by bacterial overgrowth was not supported, suggesting a need for revision of principles for antibiotic therapy. In individual patients, the management of chronic bronchial infection may be improved by therapy specific to their microbiome, taking into account pathogen load, community stability, and acute and chronic community responses to antibiotics.

Variability of sweat chloride concentration in subjects with cystic fibrosis and G551D mutations

INTRODUCTIONnSweat chloride concentration, a biomarker of CFTR function, is an appropriate outcome parameter in clinical trials aimed at correcting the basic CF defect. Although there is consensus on a cut-off value to diagnose CF, we have only limited information on the within subject variability of sweat chloride over time. Such information would be useful for sample size calculations in clinical trials. Therefore, we retrospectively analyzed repeated sweat chloride values obtained in patients with G551D mutation(s) assigned to placebo in an ivacaftor interventional trial.nnnMETHODSnIn subjects with G551D at least 12years of age, a pilocarpine sweat test using Macroduct collector was taken on both arms at 8 time points over 48weeks. We explored 1062 pilocarpine sweat test values obtained in 78 placebo patients of the VX08-770-102 trial.nnnRESULTSnMean overall sweat chloride value (all patients, all tests, n=1062) was 100.8mmol/L (SD 12.7mmol/L). Using a multilevel mixed model, the between-subject standard deviation (SD) for sweat chloride was 8.9mmol/L (95% CI 7.4-10.6) and within-subject SD was 8.1mmol/L (95% CI 7.5-8.7). Limits of repeatability for repeat measurements were -19.7 to +21.6mmol/L using values from one arm, and -13.3 to 11.8mmol/L using mean of values obtained at 4 test occasions. Sample size calculations showed that the minimal treatment effect on sweat chloride concentration that can be demonstrated for a group of 5 patients is around 15mmol/L, using a cross-over design and combinations of 4 tests for each phase of the trial.nnnCONCLUSIONnAlthough the sweat test is considered a robust measure, sweat chloride measurements in patients with CF and a G551D mutation had an inherent biological variability that is higher than commonly considered. Further analyses of placebo group data are crucial to learn more about the natural variability of this outcome parameter.