Endpoints for clinical trials in young children with cystic fibrosis

MR Perfusion Imaging of the Lung

Lung perfusion assessment is critical for diagnosing and monitoring a variety of respiratory conditions. MRI perfusion provides a radiation-free technique, making it an ideal choice for longitudinal imaging in younger populations. This review focuses on the techniques and applications of MRI perfusion, including contrast-enhanced (CE) MRI and non-CE methods such as arterial spin labeling (ASL), fourier decomposition (FD), and hyperpolarized 129-Xenon (129-Xe) MRI. ASL leverages endogenous water protons as tracers for a non-invasive measure of lung perfusion, while FD offers simultaneous measurements of lung perfusion and ventilation, enabling the generation of ventilation/perfusion mapsHyperpolarized 129-Xe MRI emerges as a novel tool for assessing regional gas exchange in the lungs. Despite the promise of MRI perfusion techniques, challenges persist, including competition with other imaging techniques and the need for additional validation and standardization. In conditions such as cystic fibrosis and lung cancer, MRI has displayed encouraging results, whereas in diseases like chronic obstructive pulmonary disease, further validation remains necessary. In conclusion, while MRI perfusion techniques hold immense potential for a comprehensive, non-invasive assessment of lung function and perfusion, their broader clinical adoption hinges on technological advancements, collaborative research, and rigorous validation.

Deep Learning Approaches for Quantifying Ventilation Defects in Hyperpolarized Gas Magnetic Resonance Imaging of the Lung: A Review

This paper provides an in-depth overview of Deep Neural Networks and their application in the segmentation and analysis of lung Magnetic Resonance Imaging (MRI) scans, specifically focusing on hyperpolarized gas MRI and the quantification of lung ventilation defects. An in-depth understanding of Deep Neural Networks is presented, laying the groundwork for the exploration of their use in hyperpolarized gas MRI and the quantification of lung ventilation defects. Five distinct studies are examined, each leveraging unique deep learning architectures and data augmentation techniques to optimize model performance. These studies encompass a range of approaches, including the use of 3D Convolutional Neural Networks, cascaded U-Net models, Generative Adversarial Networks, and nnU-net for hyperpolarized gas MRI segmentation. The findings highlight the potential of deep learning methods in the segmentation and analysis of lung MRI scans, emphasizing the need for consensus on lung ventilation segmentation methods.

Could automated analysis of chest X-rays detect early bronchiectasis in children?

Non-cystic fibrosis bronchiectasis is increasingly described in the paediatric population. While diagnosis is by high-resolution chest computed tomography (CT), chest X-rays (CXRs) remain a first-line investigation. CXRs are currently insensitive in their detection of bronchiectasis. We aim to determine if quantitative digital analysis allows CT features of bronchiectasis to be detected in contemporaneously taken CXRs. Regions of radiologically (A) normal, (B) severe bronchiectasis, (C) mild airway dilation and (D) other parenchymal abnormalities were identified in CT and mapped to corresponding CXR. An artificial neural network (ANN) algorithm was used to characterise regions of classes A, B, C and D. The algorithm was then tested in 13 subjects and compared to CT scan features. Structural changes in CT were reflected in CXR, including mild airway dilation. The areas under the receiver operator curve for ANN feature detection were 0.74 (class A), 0.71 (class B), 0.76 (class C) and 0.86 (class D). CXR analysis identified CT measures of abnormality with a better correlation than standard radiological scoring at the 99% confidence level.Conclusion: Regional abnormalities can be detected by digital analysis of CXR, which may provide a low-cost and readily available tool to indicate the need for diagnostic CT and for ongoing disease monitoring. What is Known: • Bronchiectasis is a severe chronic respiratory disorder increasingly recognised in paediatric populations. • Diagnostic computed tomography imaging is often requested only after several chest X-ray investigations. What is New: • We show that a digital analysis of chest X-ray could provide more accurate identification of bronchiectasis features.

Outcomes and endpoints reported in studies of pulmonary exacerbations in people with cystic fibrosis: A systematic review

BACKGROUND

There is no consensus about which outcomes should be evaluated in studies of pulmonary exacerbations in people with cystic fibrosis (CF). Outcomes used for evaluation should be meaningful; that is, they should capture how people feel, function or survive and be acknowledged as important to people with CF, or should be reliable surrogates of those outcomes. We aimed to summarise the outcomes and corresponding endpoints which have been reported in studies of pulmonary exacerbations, and to identify those which are most likely to be meaningful.

METHODS

A PROSPERO registered systematic review (CRD42020151785) was conducted in Medline, Embase and Cochrane from inception until July 2020. Registered trials were also included.

RESULTS

144 studies met the inclusion criteria. A wide range of outcomes and corresponding endpoints were reported. Death, QoL and many patient-reported outcomes are likely to be meaningful as they directly capture how people feel, function or survive. Forced expiratory volume in 1-second [FEV₁] is a validated surrogate of risk of death and reduced QoL. The extent of structural lung disease has also been correlated with lung function, pulmonary exacerbations and risk of death. Since no evidence of a correlation between airway microbiology or biomarkers with clinically meaningful outcomes was found, the value of these as surrogates was unclear.

CONCLUSIONS

Death, QoL, patient-reported outcomes, FEV₁, and structural lung changes were identified as outcomes that are most likely to be meaningful. Development of a core outcome set in collaboration with stakeholders including people with CF is recommended.

Current state of the art MRI for the longitudinal assessment of cystic fibrosis

Pulmonary MRI can now provide high-resolution images that are sensitive to early disease and specific to inflammation in cystic fibrosis (CF) lung disease. With specificity and function limited via computed tomography (CT), there are significant advantages to MRI. Many of the modern MRI techniques can be performed throughout life, and can be employed to understand changes over time, in addition to quantification of treatment response. Proton density and T1 /T2 contrast images can be obtained within a single breath-hold, providing depiction of structural abnormalities and active inflammation. Modern radial and/or spiral ultrashort echo-time (UTE) techniques rival CT in resolution for depiction and quantification of structure, for both airway and parenchymal abnormalities. Contrast perfusion MRI techniques are now utilized routinely to visualize changes in pulmonary and bronchial circulation that routinely occur in CF lung disease, and noncontrast techniques are moving closer to clinical translation. Functional information can be obtained from noncontrast proton images alone, using techniques such as Fourier decomposition. Hyperpolarized-gas MRI, increasingly using 129 Xe, is now becoming more widespread and has been demonstrated to have high sensitivity to early airway obstruction in CF via ventilation MRI. The sensitivity of 129 Xe MRI promises future use in personalized medicine, management of early CF lung disease, and in future clinical trials. By combining structural and functional techniques, with or without hyperpolarized gases, regional structure-function relationships can be obtained, giving insight into the pathophysiology of disease and improved clinical management. This article reviews the modern MRI techniques that can routinely be employed for CF lung disease in nearly any large medical center. Level of Evidence: 4 Technical Efficacy Stage: 5 J. Magn. Reson. Imaging 2019.

Rationale and study design of the MyHEART study: A young adult hypertension self-management randomized controlled trial

Young adults (18-39 year-olds) with hypertension have a higher lifetime risk for cardiovascular disease. However, less than 50% of young adults achieve hypertension control in the United States. Hypertension self-management programs are recommended to improve control, but have been targeted to middle-aged and older populations. Young adults need hypertension self-management programs (i.e., home blood pressure monitoring and lifestyle modifications) tailored to their unique needs to lower blood pressure and reduce the risks and medication burden they may face over a lifetime. To address the unmet need in hypertensive care for young adults, we developed MyHEART (My Hypertension Education And Reaching Target), a multi-component, theoretically-based intervention designed to achieve self-management among young adults with uncontrolled hypertension. MyHEART is a patient-centered program, based upon the Self-Determination Theory, that uses evidence-based health behavior approaches to lower blood pressure. Therefore, the objective of this study is to evaluate MyHEART's impact on changes in systolic and diastolic blood pressure compared to usual care after 6 and 12 months in 310 geographically and racially/ethnically diverse young adults with uncontrolled hypertension. Secondary outcomes include MyHEART's impact on behavioral outcomes at 6 and 12 months, compared to usual clinical care (increased physical activity, decreased sodium intake) and to examine whether MyHEART's effects on self-management behavior are mediated through variables of perceived competence, autonomy, motivation, and activation (mediation outcomes). MyHEART is one of the first multicenter, randomized controlled hypertension trials tailored to young adults with primary care. The design and methodology will maximize the generalizability of this study. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03158051.

Azithromycin for Early Pseudomonas Infection in Cystic Fibrosis. The OPTIMIZE Randomized Trial

RATIONALE

New isolation of Pseudomonas aeruginosa (Pa) is generally treated with inhaled antipseudomonal antibiotics such as tobramycin inhalation solution (TIS). A therapeutic approach that complements traditional antimicrobial therapy by reducing the risk of pulmonary exacerbation and inflammation may ultimately prolong the time to Pa recurrence.

OBJECTIVES

To test the hypothesis that the addition of azithromycin to TIS in children with cystic fibrosis and early Pa decreases the risk of pulmonary exacerbation and prolongs the time to Pa recurrence.

METHODS

The OPTIMIZE (Optimizing Treatment for Early Pseudomonas aeruginosa Infection in Cystic Fibrosis) trial was a multicenter, double-blind, randomized, placebo-controlled, 18-month trial in children with CF, 6 months to 18 years of age, with early Pa. Azithromycin or placebo was given 3× weekly with standardized TIS.

MEASUREMENTS AND MAIN RESULTS

The primary endpoint was the time to pulmonary exacerbation requiring antibiotics and the secondary endpoint was the time to Pa recurrence, in addition to other clinical and safety outcomes. A total of 221 participants (111 placebo, 110 azithromycin) out of a planned 274 were enrolled. Enrollment was stopped early by the NHLBI because the trial had reached the prespecified interim boundary for efficacy. The risk of pulmonary exacerbation was reduced by 44% in the azithromycin group as compared with the placebo group (hazard ratio, 0.56; 95% confidence interval, 0.37-0.83; P = 0.004). Weight increased by 1.27 kg in the azithromycin group compared with the placebo group (95% confidence interval, 0.01-2.52; P = 0.046). No significant differences were seen in microbiological or other clinical or safety endpoints.

CONCLUSIONS

Azithromycin was associated with a significant reduction in the risk of pulmonary exacerbation and a sustained improvement in weight, but had no impact on microbiological outcomes in children with early Pa. Clinical trial registered with clinicaltrials.gov (NCT02054156).

Ultrashort Echo-Time Magnetic Resonance Imaging Is a Sensitive Method for the Evaluation of Early Cystic Fibrosis Lung Disease

RATIONALE

Recent advancements that have been made in magnetic resonance imaging (MRI) improve our ability to assess pulmonary structure and function in patients with cystic fibrosis (CF). A nonionizing imaging modality that can be used as a serial monitoring tool throughout life can positively affect patient care and outcomes.

OBJECTIVES

To compare an ultrashort echo-time MRI method with computed tomography (CT) as a biomarker of lung structure abnormalities in young children with early CF lung disease.

METHODS

Eleven patients with CF (mean age, 31.8 ± 5.7 mo; median age, 33 mo; 7 male and 4 female) were imaged via CT and ultrashort echo-time MRI. Eleven healthy age-matched patients (mean age, 22.5 ± 10.2 mo; median age, 23 mo; 5 male and 6 female) were imaged via ultrashort echo-time MRI. CT scans of 13 additional patients obtained for clinical indications not affecting the heart or lungs and interpreted as normal provided a CT control group (mean age, 24.1 ± 11.7 mo; median age, 24 mo; 6 male and 7 female). Studies were scored by two experienced radiologists using a well-validated CF-specific scoring system for CF lung disease.

MEASUREMENTS AND MAIN RESULTS

Correlations between CT and ultrashort echo-time MRI scores of patients with CF were very strong, with P values ≤0.001 for bronchiectasis (r = 0.96) and overall score (r = 0.90), and moderately strong for bronchial wall thickening (r = 0.62, P = 0.043). MRI easily differentiated CF and control groups via a reader CF-specific scoring system.

CONCLUSIONS

Ultrashort echo-time MRI detected structural lung disease in very young patients with CF and provided imaging data that correlated well with CT. By quantifying early CF lung disease without using ionizing radiation, ultrashort echo-time MRI appears well suited for pediatric patients requiring longitudinal imaging for clinical care or research studies. Clinical Trial registered with www.clinicaltrials.gov (NCT01832519).

Technological advances shed light on left ventricular cardiac disturbances in cystic fibrosis

Cystic fibrosis (CF), the most common autosomal recessive lethal disease in Caucasians, causes chronic pulmonary disease and can lead to cor pulmonale with right ventricular dysfunction. The presence of the cystic fibrosis transmembrane conductance regulator (CFTR) in cardiac myocardia has prompted debate regarding possible defective ion channel-induced cardiomyopathy. Clinical heart disease in CF is considered rare and is restricted to case reports. It has been unclear if this is due to the lack of physiological importance of CFTR in the heart, the relatively short lifespan of those with CF, or a technical inability to detect subclinical disease. Extensive echocardiographic investigations have yielded contradictory results, leading to the dogma that left ventricular defects in CF occur secondary to lung disease. In this review, we consider why studies examining heart function in CF have not provided clarity on this topic. We then focus on data from new echocardiographic and magnetic resonance imaging technology, which are providing greater insight into cardiac function in CF and demonstrating that, in addition to secondary effects from pulmonary disease, there may be an intrinsic primary defect in the CF heart. With advancing lifespans and activity levels, understanding the risk of cardiac disease is vital to minimizing morbidity in adults with CF.

The Evolution of Cystic Fibrosis Care

Cystic fibrosis (CF) is the most common life-limiting inherited illness of whites. Most of the morbidity and mortality in CF stems from impaired mucociliary clearance leading to chronic, progressive airways obstruction and damage. Significant progress has been made in the care of patients with CF, with advances focused on improving mucociliary clearance, minimizing inflammatory damage, and managing infections; these advances include new antimicrobial therapies, mucolytic and osmotic agents, and antiinflammatory treatments. More recently, researchers have targeted disease-causing mutations using therapies to promote gene transcription and improve channel function, which has led to impressive physiologic changes in some patients. As we develop more advanced, allele-directed therapies for the management of CF, it will become increasingly important to understand the specific genetic and environmental interactions that cause the significant heterogeneity of lung disease seen in the CF population. This understanding of CF endotypes will allow for more targeted, personalized therapies for future patients. This article reviews the genetic and molecular basis of CF lung disease, the treatments currently available, and novel therapies that are in development.

Changes in Pulmonary Function and Controlled Ventilation-High Resolution CT of Chest After Antibiotic Therapy in Infants and Young Children with Cystic Fibrosis

BACKGROUND

Infants with cystic fibrosis (CF) develop early progressive lung disease which may be asymptomatic. Infant pulmonary function tests (IPFT) and controlled ventilation-high resolution computed tomography (CV-HRCT) of chest can detect early asymptomatic lung disease. It is not well established that these objective measures can detect changes in lung disease after clinical interventions.

OBJECTIVE

The purpose of this study was to evaluate usefulness of IPFT and CV-HRCT to detect changes in lung disease after intravenous (IV) antibiotic therapy in infants with early CF-related lung disease.

STUDY DESIGN

IPFTs and CV-HRCT done before and after 2 weeks of IV antibiotics in infants at our institution over the last 12 years were compared. CV-HRCTs were compared using the modified Brody scoring system.

RESULTS

The sample included 21 infants, mean age 85.2 ± 47.6 weeks. Mean change in weight was 0.4 ± 0.38 kg (p = 0.001). Significant changes in IPFT included mean % predicted FEV(0.5) (+13.5 %, p = 0.043), mean %FEF(25-75) (+30.2 %, p = 0.008), mean %RV/TLC (-11.2 %, p = 0.008), and mean %FRC/TLC (-4.5 %, p = 0.001). Total Brody scores improved from a median of 10 to 5 (p < 0.001) as did mean scores for airway wall thickening (p = 0.050), air trapping (p < 0.001), and parenchymal opacities (p = 0.003).

CONCLUSION

IPFT and CV-HRCT can be used as objective measures of improvement in lung disease for infants with CF treated with antibiotics.

Cystic fibrosis: NHLBI Workshop on the Primary Prevention of Chronic Lung Diseases

Cystic fibrosis (CF) is a life-limiting, monogenic disorder characterized by chronic sinopulmonary and gastrointestinal involvement. Progressive pulmonary disease leads to death in the majority of patients. Despite its well-defined molecular basis related to defects in the cystic fibrosis transmembrane conductance regulator anion transport channel, there are large gaps in our understanding of the origin of CF lung disease. Disease has been shown to be present in infancy, and there is mounting evidence that abnormalities begin in utero. Heterogeneity of clinical presentations and severity suggest that many factors involved in lung disease have yet to be fully elucidated. Although new advances in therapeutic treatments have shown promise in delaying disease progression, the prevention of pulmonary disease at its origin (primary prevention) should be a key goal of CF care. The objective of this workshop was to (1) review our understanding of the origins of CF lung disease, (2) determine gaps in the knowledge base that are most significant and most likely to enable prevention of CF lung disease, and (3) prioritize new research questions that will promote pulmonary health in both CF and other childhood lung diseases. The goal of this report is to provide recommendations for future research that will improve our understanding of pulmonary development in health and disease, improve outcome measures and biomarkers for early lung disease, and determine therapeutic targets and strategies to prevent the development of lung disease in children with CF.

Tracking CF disease progression with CT and respiratory symptoms in a cohort of children aged 6-19 years

INTRODUCTION

Cystic fibrosis (CF) lung disease is characterized by bronchiectasis and trapped air on chest computed tomography (CT).

OBJECTIVE

We aim to validate bronchiectasis and trapped air as outcome measures by evaluating associations between changes in bronchiectasis, trapped air and patient-reported respiratory symptoms.

METHODS

A longitudinal cohort study has been conducted. CF patients (aged 6-19 years) who had two routine CTs and completed twice a Cystic Fibrosis Questionnaire-Revised within 2 years (referred to as T1 and T2 ), in the period of July 2007 to January 2012 were included. Bronchiectasis and trapped air were scored using the CF-CT scoring system. Correlation coefficients and student's paired t tests were performed.

RESULTS

In total 40 patients were included with a median age at T1 of 12.6 years (range 6-17 years), and at T2 14.5 years (range 8-19 years). At T1 , bronchiectasis (r = -0.49, P < 0.01) and trapped air (r = -0.34, P = 0.04) correlated with CFQ-R Respiratory Symptoms Scores (CFQ-R RSS). At T2 similar correlations were found with the CFQ-R RSS. Over 2 years, there was significant progression in bronchiectasis (P = 0.03) and trapped air (P = 0.03), but not in CFQ-R RSS. Changes in bronchiectasis and trapped air were not associated with changes in CFQ-R RSS.

CONCLUSION

Our results indicate that bronchiectasis and trapped are sensitive outcome measures in CF lung disease, showing a significant association with CFQ-R RSS at two-time points. However, progression of bronchiectasis and trapped air over 2 year does not necessarily correlate to changes in quality of life.

Predictors and outcome of low initial forced expiratory volume in 1 second measurement in children with cystic fibrosis

OBJECTIVE

To identify the characteristics of children with cystic fibrosis with low initial forced expiratory volume in 1 second (FEV1) % predicted and to investigate their outcome.

STUDY DESIGN

Patients were categorized into low or high initial FEV1 groups using cluster analysis. Comparisons of the demographic and clinical data were performed between the 2 groups.

RESULTS

From 122 children, 21 clustered into the low and 101 into the high FEV1 group. The mean FEV1 was 69% ± 12% predicted for the low and 95% ± 12% predicted for the high FEV1 group (P < .001). The low FEV1 group had lower body mass index percentiles (P = .003), were hospitalized more frequently (P = .001), and had been on dornase alfa longer (P = .006). Low FEV1 group had more patients with positive cultures for Pseudomonas aeruginosa (P = .002) and Stenotrophomonas maltophilia (P < .001) and had more total number of cultures positive for mucoid P. aeruginosa (P = .009) and methicillin resistant Staphylococcus aureus + P. aeruginosa (P = .005). The low FEV1 group continued to have low FEV1 measurements, their FEV1 declined slower, required more hospitalizations per year (P = .01), and had more cultures for mucoid (P = .003) and nonmucoid P. aeruginosa (P = .02) ± methicillin resistant S. aureus (P = .002) in comparison with the high FEV1 group. Poor adherence was associated with lower initial FEV1 values in females, and early, rapid decline of FEV1 in males.

CONCLUSIONS

Some children with cystic fibrosis may present with poor lung function early in life and continue to have subnormal lung function associated with reduced body mass index, more frequent hospitalization, and higher rates of infection. Such children may benefit from careful evaluation and close follow-up.

Tracking Lung Clearance Index and chest CT in mild cystic fibrosis lung disease over a period of three years

INTRODUCTION

Lung disease remains the main cause of morbidity and mortality in patients with Cystic Fibrosis (CF). To detect lung disease before clinical symptoms become apparent, sensitive tools are essential. Spirometry is used for monitoring, but the FEV1 remains frequently normal throughout childhood. The Lung Clearance Index (LCI) calculated from Multiple Breath Washout (MBW) was introduced at the CF centre Innsbruck in 2007 for assessing ventilation inhomogeneity in patients with mild lung disease. We hypothesized that LCIs in 2007 are of prognostic value for the presence or absence of structural lung changes in later years.

METHODS

Between 2007 and 2010 MBW, spirometry and ultra-low-dose HR-CT were prospectively tracked in 36 patients (6-53 years) with a mean FEV1 ≥ 80% predicted in 2007.

RESULTS

At study start the majority of patients had abnormal CT scores and LCI results. While CT and spirometry remained largely stable throughout the study, LCI results slightly improved but still correlated with CT scores in 2010. LCI results in 2007 correlated with CT scores in 2010 while FEV1 did not. In 86% the LCI value in 2007 was indicative for the presence or absence of structural lung changes in 2010.

CONCLUSION

The LCI is a sensitive tool for detecting and tracking pulmonary changes. Extended structural changes are unlikely if the LCI is normal. The LCI has the potential to be used for monitoring the progression of early CF lung disease and assessing the effect of treatment in both clinical care and research settings.

Survey of clinical infant lung function testing practices

BACKGROUND

Data supporting the clinical use of infant lung function (ILF) tests are limited making the interpretation of clinical ILF measures difficult.

OBJECTIVES

To evaluate current ILF testing practices and to survey users regarding the indications, limitations and perceived clinical benefits of ILF testing.

METHODS

We created a 26-item survey hosted on the European Respiratory Society (ERS) website between January and May 2010. Notifications were sent to members of the ERS, American Thoracic Society and the Asian Pacific Society of Respirology. Responses were sought from ILF laboratory directors and pediatric respirologists. The survey assessed the clinical indications, patient populations, equipment and reference data used, and perceived limitations of ILF testing.

RESULTS

We received 148 responses with 98 respondents having ILF equipment and performing testing in a clinical capacity. Centers in North America were less likely to perform ≥50 studies/year than centers in Europe or other continents (13% vs. 41%). Most respondents used ILF data to either "start a new therapy" (78%) or "help decide about initiation of further diagnostic workup such as bronchoscopy, chest CT or serological testing" (69%). Factors reported as limiting clinical ILF testing were need for sedation, uncertainty regarding clinical impact of study results and time intensive nature of the study.

CONCLUSIONS

Clinical practices associated with ILF testing vary significantly; centers that perform more studies are more likely to use the results for clinical purposes and decision making. The future of ILF testing is uncertain in the face of the limitations perceived by the survey respondents.

Challenges and limitations of testing efficacy of aerosol device delivery in young children

An increasing number of medical conditions are chronically or acutely managed with some form of aerosolized therapy. Due to the benefit of directly administering medications to the intended site of action, there is great interest in evaluating treatments for aerosol use. One of the major challenges in selecting and testing new drug-device combinations in children is the uncertainty regarding the appropriate outcome measure to choose. In studies involving adult patients, typically exacerbations of disease or airflow obstruction are assessed as endpoints in drug trials or device assessment. However, in young children, choosing endpoints to assess efficacy is difficult due to the potential lack of sensitive, noninvasive endpoints that are easily performed across sites. In this review, we discuss the challenges and limitations of selecting clinical endpoints for drug-device trials in the youngest population, with a focus on novel emerging technologies. This article provides an overview of preschool and infant pulmonary function testing, multiple-breath washout, imaging techniques including computed tomography and magnetic resonance imaging, flexible bronchoscopy in children, mucociliary clearance scans, and exhaled breath condensate.

Hypertonic saline is effective in the prevention and treatment of mucus obstruction, but not airway inflammation, in mice with chronic obstructive lung disease

Recent evidence suggests that inadequate hydration of airway surfaces is a common mechanism in the pathogenesis of airway mucus obstruction. Inhaled hypertonic saline (HS) induces osmotic water flux, improving hydration of airway surfaces. However, trials in patients with obstructive lung diseases are limited. The aim of this study was to investigate effects of HS on mucus obstruction and airway inflammation in the prevention and treatment of obstructive lung disease in vivo. We, therefore, used the β-epithelial Na(+) channel (βENaC)-overexpressing mouse as a model of chronic obstructive lung disease and determined effects of preventive and late therapy with 3% HS and 7% HS on pulmonary mortality, airway mucus obstruction, and inflammation. We found that preventive treatment with 3% HS and 7% HS improved growth, reduced mortality, and reduced mucus obstruction in neonatal βENaC-overexpressing mice. In adult βENaC-overexpressing mice with chronic lung disease, mucus obstruction was significantly reduced by 7% HS, but not by 3% HS. Treatment with HS triggered airway inflammation with elevated keratinocyte chemoattractant levels and neutrophils in airways from wild-type mice, but reduced keratinocyte chemoattractant in chronic neutrophilic inflammation in adult βENaC-overexpressing mice. Our data demonstrate that airway surface rehydration with HS provides an effective preventive and late therapy of mucus obstruction with no consistent effects on inflammation in chronic lung disease. These results suggest that, through mucokinetic effects, HS may be beneficial for patients with a spectrum of obstructive lung diseases, and that additional strategies are required for effective treatment of associated airway inflammation.

Magnetic resonance imaging of pediatric lung parenchyma, airways, vasculature, ventilation, and perfusion: state of the art

Magnetic resonance (MR) imaging is a noninvasive imaging modality, particularly attractive for pediatric patients given its lack of ionizing radiation. Despite many advantages, the physical properties of the lung (inherent low signal-to-noise ratio, magnetic susceptibility differences at lung-air interfaces, and respiratory and cardiac motion) have posed technical challenges that have limited the use of MR imaging in the evaluation of thoracic disease in the past. However, recent advances in MR imaging techniques have overcome many of these challenges. This article discusses these advances in MR imaging techniques and their potential role in the evaluation of thoracic disorders in pediatric patients.

Pulmonary exacerbations in CF patients with early lung disease

BACKGROUND

Current definitions of pulmonary exacerbation (PE) in cystic fibrosis are based on studies in participants with significant lung disease and may not reflect the spectrum of findings observed in younger patients with early lung disease.

METHODS

We used data from a recent trial assessing the efficacy of azithromycin in children to study signs and symptoms associated with PEs and related changes in lung function and weight.

RESULTS

While increased cough was present in all PEs, acute weight loss and reduction in oxygen saturation were not observed. Changes in lung function did not differ between subjects who did experience a PE and those who were exacerbation-free.

CONCLUSIONS

Cough was the predominant symptom in CF patients with early lung disease experiencing a PE. There was no significant difference in mean 6-month change in lung function or weight among subjects with one or more exacerbations and those without an exacerbation.

Novel end points for clinical trials in young children with cystic fibrosis

Cystic fibrosis (CF) lung disease commences early in the disease progression and is the most common cause of mortality. While new CF disease-modifying agents are currently undergoing clinical trial evaluation, the implementation of such trials in young children is limited by the lack of age-appropriate clinical trial end points. Advances in infant and preschool lung function testing, imaging of the chest and the development of biochemical biomarkers have led to increased possibility of quantifying mild lung disease in young children with CF and objectively monitoring disease progression over the course of an intervention. Despite this, further standardization and development of these techniques is required to provide robust objective measures for clinical trials in this age group.

Molecular analysis of changes in Pseudomonas aeruginosa load during treatment of a pulmonary exacerbation in cystic fibrosis

BACKGROUND

Intravenous antibiotics for pulmonary exacerbations (PEs) of cystic fibrosis (CF) usually target Pseudomonas aeruginosa. Insights into the CF lung microbiome have questioned this approach. We used RT-qPCR to determine whether intravenous antibiotics reduced P. aeruginosa numbers and whether this correlated with improved lung function. We also investigated antibiotic effects on other common respiratory pathogens in CF.

METHODS

Sputa were collected from patients when stable and again during a PE. Sputa were expectorated into a RNA preservation buffer for RNA extraction and preparation of cDNA. qPCR was used to enumerate viable P. aeruginosa as well as Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus, Burkholderia cepacia complex and Aspergillus fumigatus.

RESULTS

Fifteen CF patients were followed through 21 PEs. A complete set of serial sputum samples was unavailable for two patients (three separate PEs). P. aeruginosa numbers did not increase immediately prior to a PE, but numbers during intravenous antibiotic treatment were reduced ≥4-log in 6/18 and ≥1-log in 4/18 PEs. In 7/18 PEs, P. aeruginosa numbers changed very little with intravenous antibiotics and one patient demonstrated a ≥2-log increase in P. aeruginosa load. H. influenzae and S. pneumoniae were detected in ten and five PEs respectively, but with antibiotic treatment these bacteria rapidly became undetectable in 6/10 and 4/5 PEs, respectively. There was a negative correlation between P. aeruginosa numbers and FEV1 during stable phase (r(s)=0.75, p<0.05), and reductions in P. aeruginosa load with intravenous antibiotic treatment correlated with improved FEV1 (r(s)=0.52, p<0.05).

CONCLUSIONS

Exacerbations are not due to increased P. aeruginosa numbers in CF adults. However, lung function improvements correlate with reduced P. aeruginosa burden suggesting that current antibiotic treatment strategies remain appropriate in most patients. Improved understanding of PE characterised by unchanged P. aeruginosa numbers and minimal lung function improvement following treatment may allow better targeted therapies.

Effect of azithromycin on systemic markers of inflammation in patients with cystic fibrosis uninfected with Pseudomonas aeruginosa

BACKGROUND

While the mechanism of action by which azithromycin exerts positive effects inpatients with cystic fibrosis remains unclear, evidence suggests that azithromycin may act as an immunomodulatory agent. We examined changes in systemic inflammatory markers in a doubleblind, randomized, controlled trial of oral azithromycin in patients 6-18 years of age with cystic fibrosis who were uninfected with Pseudomonas aeruginosa.

METHODS

WBC counts and differential, serum myeloperoxidase (MPO), high-sensitivity C reactive protein (hsCRP), intracellular adhesion molecule 1, IL-6, calprotectin, serum amyloid A (SAA),and granulocyte colony-stimulating factor (G-CSF) were measured at baseline and after 28 and 168 days of treatment in patients receiving either oral azithromycin or placebo.

RESULTS

Inflammatory markers were similar in both groups at baseline. HsCRP, MPO, SAA, calprotectin,and the absolute neutrophil count (ANC) significantly decreased from baseline today 28 in the azithromycin group compared with the placebo group ( P < .05). This treatment effect was sustained at day 168 for ANC, calprotectin, and SAA ( P < .05). Changes in hsCRP, calprotectin,and SAA at day 28 were negatively correlated with changes in FEV 1 (L) and FEV 1(% predicted), as well as both absolute and relative changes in weight ( P < .05). Except for weight (%),the associations remained significant for calprotectin; FEV 1 (L) and weight (%) remained significantly correlated with the 168-day change in hsCRP. The 168-day change in ANC was significantly correlated with changes in lung function, but not in weight; the change in G-CSF was significantly correlated with the change in weight (%) only.

CONCLUSIONS

In patients not infected with P aeruginosa , oral azithromycin significantly reduced neutrophil counts and serum inflammatory markers within 28 days of initiating treatment.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT00431964; URL: www.clinicaltrials.gov

Progress in cystic fibrosis and the CF Therapeutics Development Network

Cystic fibrosis (CF), the most common life-shortening genetic disorder in Caucasians, affects approximately 70 000 individuals worldwide. In 1998, the Cystic Fibrosis Foundation (CFF) launched the CF Therapeutics Development Network (CF-TDN) as a central element of its Therapeutics Development Programme. Designed to accelerate the clinical evaluation of new therapies needed to fulfil the CFF mission to control and cure CF, the CF-TDN has conducted 75 clinical trials since its inception, and has contributed to studies as varied as initial safety and proof of concept trials to pivotal programmes required for regulatory approval. This review highlights recent and significant research efforts of the CF-TDN, including a summary of contributions to studies involving CF transmembrane conductance regulator (CFTR) modulators, airway surface liquid hydrators and mucus modifiers, anti-infectives, anti-inflammatories, and nutritional therapies. Efforts to advance CF biomarkers, necessary to accelerate the therapeutic goals of the network, are also summarised.

Nasal versus oronasal raised volume forced expirations in infants--a real physiologic challenge

Raised volume rapid thoracoabdominal compression (RTC) generates forced expiration (FE) in infants typically from an airway opening pressure of 30 cm H(2)O (V(30)). We hypothesized that the higher nasal than pulmonary airway resistance limits forced expiratory flows (FEF(%)) during (nasal) FE(n), which an opened mouth, (oronasal) FE(o), would resolve. Measurements were performed during a brief post-hyperventilation apnea on 12 healthy infants aged 6.9-104 weeks. In two infants, forced expiratory (FEFV) flow volume (FV) curves were generated using a facemask that covered the nose and a closed mouth, then again with a larger mask with the mouth opened. In other infants (n = 10), the mouth closed spontaneously during FE. Oronasal passive expiration from V(30) generated either the inspiratory capacity (IC) or by activating RTC before end-expiration, the slow vital capacity ((j) SVC). Peak flow (PF), FEF(25), FEF(50), FEF(25-75), FEV(0.4), and FEV(0.5) were lower via FE(n) than FE(o) (P < 0.05), but the ratio of expired volume at PF and forced vital capacity (FVC) as percent was higher (P < 0.05). FEF(75), FEF(85), FEF(90), FVC as well as the applied jacket pressures were not different (P > 0.05). FEFV curves generated via FE(o) exhibited higher PF than FV curves of IC (P < 0.05); PF of those produced via FE(n) were not different from FV curves of IC (P > 0.05) but lower than those of (j) SVC (P < 0.05). In conclusion, the higher nasal than pulmonary airways resistance unequivocally affects the FEFV curves by consistently reducing PF and decreases mid-expiratory flows. A monitored slightly opened mouth and a gentle anterior jaw thrust are physiologically integral for raised volume RTC in order to maximize the oral and minimize nasal airways contribution to FE so that flow limitation would be in the pulmonary not nasal airways.

Feasibility and variability of measuring the Lung Clearance Index in a multi-center setting

The Lung Clearance Index (LCI) is superior to spirometry in detecting early lung disease in cystic fibrosis (CF) and correlates with structural lung changes seen on CT scans. The LCI has the potential to become a novel outcome parameter for clinical and research purposes. However longitudinal studies are required to further prove its prognostic value. Multi-center design is likely to facilitate realization of such studies. Therefore the aim of the present study was to assess multi-center feasibility and inter-center variability of LCI measurements in healthy children and adolescents. Comparative measurements were performed in unselected patients with CF to confirm previous single-center results. LCI measurements were performed in eight centers using the EasyOne Pro, MBW Module (ndd Medical Technologies, Zurich, Switzerland). The overall success rate for LCI measurements was 75.5%, leaving 102/151 measurements in healthy volunteers and 139/183 measurements in patients with CF for final analysis. Age ranged between 4 and 24 years. Mean LCI (range of means among centers) was 6.3 (6.0-6.5) in healthy volunteers and thus normal. Inter-center variability of center means was 2.9%, ANOVA including Schffé procedure demonstrated no significant inter-center differences (P > 0.05). Mean LCI (range of means among centers) was 8.2 (7.4-8.9) in CF and thus abnormal. Our study demonstrates good multi-center feasibility and low inter-center variability of the LCI in healthy volunteers when measured with the EasyOne Pro MBW module. Our data confirm published LCI data in CF. However, central coordination, quality control, regular training, and supervision during the entire study appear essential for successfully performing multi-center trials.

Improvement in pulmonary function following antibiotics in infants with cystic fibrosis

BACKGROUND

Recent studies have shown the presence of lung disease in even asymptomatic infants with cystic fibrosis (CF). While pulmonary function testing (PFT) is often used to follow progression of lung disease and guide treatment in older children with CF, little data is available on change in infant PFTs in young children with CF.

OBJECTIVE

To determine change in infant PFTs before and after antibiotic therapy for pulmonary exacerbation in infants with CF.

METHODS

Retrospective cohort study of infants with CF who underwent clinically indicated infant PFTs before and after antibiotic therapy for CF pulmonary exacerbation at the University of North Carolina at Chapel Hill.

RESULTS

Pre- and post-antibiotics PFT data was available on 11 infants with CF, with a mean age of 102 weeks at time of first PFT. The majority of infants were symptomatic prior to antibiotics, and showed statistically significant improvement in clinical parameters following treatment. Prior to antibiotics, PFTs showed evidence of substantial obstructive disease (mean z-scores for FVC, FEV(0.5) , and FEF(25-75) of -1.81, -3.06, and -4.5, respectively) and air-trapping/hyperinflation (mean z-scores for FRCpleth, RV, and RV/TLC of 8.86, 7.1, and 3.31, respectively). Following antibiotics, all of the above parameters showed statistically significant improvement.

DISCUSSION

We have shown a statistically significant improvement in infant PFT measures following antibiotic therapy in a cohort of 11 infants with CF, which paralleled improvement in clinical parameters. Though infant PFTs showed improvement, they remained abnormal in the majority of subjects, with persistent air-trapping and hyperinflation after antibiotic therapy. Our findings suggest that infant PFTs are sensitive to acute clinical changes in children with CF, and may be a useful tool in managing infants with CF.

Pulmonary magnetic resonance imaging for airway diseases

Pulmonary magnetic resonance (MR) imaging has been put forward as a new research and diagnostic tool mainly to overcome the limitations of computed tomography and nuclear medicine studies. However, pulmonary MR imaging has been difficult to use because of inherently low proton density, a multitude of air-tissue interfaces, which create significant magnetic field distortions and are commonly referred to as susceptibility artifacts; diminishing signal in the lung; and respiratory and/or cardiac motion artifacts. To overcome these drawbacks of pulmonary MR imaging, technical advances made during the last decade in sequencing, scanner and coil, adaptation of parallel imaging techniques, and utilization of contrast media have been reported as being useful for functional and morphologic assessment of various pulmonary diseases including airway diseases. This review article covers (1) pulmonary MR techniques for morphologic and functional assessment of airway diseases, and (2) pulmonary MR imaging for cystic fibrosis, asthma, and chronic obstructive pulmonary disease. Pulmonary MR imaging provides not only morphology-related but also pulmonary function-related information. It has the potential to replace nuclear medicine studies for the identification of regional pulmonary function and may perform a complementary role in airway disease assessment instead of nuclear medicine study. We believe that the findings of further basic studies as well as clinical applications of this new technique will validate the real significance of pulmonary MR imaging for the future of airway disease assessment and its usefulness for diagnostic radiology and pulmonary medicine.

Future directions in early cystic fibrosis lung disease research: an NHLBI workshop report

Since the 1989 discovery that mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene cause cystic fibrosis (CF), there has been substantial progress toward understanding the molecular basis for CF lung disease, leading to the discovery and development of new therapeutic approaches. However, the earliest impact of the loss of CFTR function on airway physiology and structure and its relationship to initial infection and inflammation are poorly understood. Universal newborn screening for CF in the United States represents an unprecedented opportunity for investigating CF clinical manifestations very early in life. Recently developed animal models with pulmonary phenotypic manifestations also provide a window into the early consequences of this genetic disorder. For these reasons, the National Heart, Lung, and Blood Institute (NHLBI) convened a working group of extramural experts, entitled "Future Research Directions in Early CF Lung Disease" on September 21-22, 2010, to identify future research directions of great promise in CF. The priority areas identified included (1) exploring pathogenic mechanisms of early CF lung disease; (2) leveraging newborn screening to elucidate the natural history of early lung disease; (3) developing a spectrum of biomarkers of early lung disease that reflects CF pathophysiology, clinical outcome, and response to treatment; (4) exploring the role of genetics/genomics (e.g., modifier genes, gene-environmental interactions, and epigenetics) in early CF pathogenesis; (5) defining early microbiological events in CF lung disease; and (6) elucidating the initial airway inflammatory, remodeling, and repair mechanisms in CF lung disease.

Outcome measures for clinical trials assessing treatment of cystic fibrosis lung disease

Cystic fibrosis (CF) is a complex genetic disease characterized by death from loss of lung function. Therapies target pathophysiologic changes associated with pulmonary disease progression. Although therapeutic mechanisms differ, efficacy demonstration is limited to a few accepted outcome measures, each with shortcomings that are becoming more pronounced as CF population health improves. Pulmonary function improvement (as forced expiratory volume in 1 s [FEV₁]) and reduction of pulmonary exacerbation risk are commonly used outcomes. Changes in FEV₁ decline rate, quality of life, linear growth and/or weight gain are less utilized outcomes. Validated outcomes tend to work best in subjects with more aggressive or advanced lung disease and less so in healthier subjects. Assays of effects on primary therapeutic targets have yet to be validated as surrogate measures of clinical efficacy. As CF population health improves, it will become increasingly difficult to employ current clinical outcome measures to demonstrate efficacy.

Radiologic imaging in cystic fibrosis: cumulative effective dose and changing trends over 2 decades

OBJECTIVE

With the increasing life expectancy for patients with cystic fibrosis (CF), and a known predisposition to certain cancers, cumulative radiation exposure from radiologic imaging is of increasing significance. This study explores the estimated cumulative effective radiation dose over a 17-year period from radiologic procedures and changing trends of imaging modalities over this period.

METHODS

Estimated cumulative effective dose (CED) from all thoracic and extrathoracic imaging modalities and interventional radiology procedures for both adult and pediatric patients with CF, exclusively attending a nationally designated CF center between 1992-2009 for > 1 year, was determined. The study period was divided into three equal tertiles, and estimated CED attributable to all radiologic procedures was estimated for each tertile.

RESULTS

Two hundred thirty patients met inclusion criteria (2,240 person-years of follow-up; 5,596 radiologic procedures). CED was > 75 mSv for one patient (0.43%), 36 patients (15.6%) had a CED between 20 and 75 mSv, 56 patients (24.3%) had a CED between 5 and 20 mSv, and in 138 patients (60%) the CED was estimated to be between 0 and 5 mSv over the study period. The mean annual CED per patient increased consecutively from 0.39 mSv/y to 0.47 mSv/y to 1.67 mSv/y over the tertiles one to three of the study period, respectively (P < .001). Thoracic imaging accounted for 46.9% of the total CED and abdominopelvic imaging accounted for 42.9% of the CED, respectively. There was an associated 5.9-fold increase in the use of all CT scanning per patient (P < .001).

CONCLUSIONS

This study highlights the increasing exposure to ionizing radiation to patients with CF as a result of diagnostic imaging, primarily attributable to CT scanning. Increased awareness of CED and strategies to reduce this exposure are needed.

Lung clearance index: clinical and research applications in children

Multiple breath washout (MBW) has been demonstrated to be sensitive for assessing ventilation inhomogeneity (VI). VI is supposed to reflect changes in peripheral airways which are not apparent using spirometry. The lung clearance index (LCI) is the most robust parameter to quantify VI, and is largely independent of age; therefore, it potentially qualifies as a surrogate outcome parameter for clinical and research purposes, particularly during childhood. This review summarizes the current evidence regarding the clinical value of measuring LCI in children. Feasibility, reproducibility and diagnostic accuracy have been demonstrated; available data confirm that LCI is superior to spirometry in detecting small air way disease. However, there is little information regarding the value in the individual patient, and sparse longitudinal data looking at its prognostic value. Currently, only in patients with Cystic Fibrosis, it appears likely that knowledge of LCI will be useful for routine clinical management.

Computed tomography score and pulmonary function in infants with chronic lung disease of infancy

Chronic lung disease of infancy (CLDI) remains a common outcome among infants born extremely prematurely. In older children and adults with lung disease, pulmonary function and computed tomography (CT) scores are used to follow up respiratory disease and assess disease severity. For infants and toddlers, however, these outcomes have been used very infrequently and most often, a dichotomous respiratory outcome (presence or absence of CLDI) is employed. We evaluated the performance of CT score and pulmonary function to differentiate infants and toddlers with CLDI from a control group. CT scans, forced expiratory flows and pulmonary diffusing capacity were obtained in 39 CLDI patients and 41 controls (aged 4-33 months). CT scans were quantified using a scoring system, while pulmonary function was expressed as Z-scores. CT score outperformed pulmonary function in identifying those with CLDI. There were no significant correlations between CT score and pulmonary function. CT score had a better performance than pulmonary function in differentiating individuals with CLDI; however, these outcomes may reflect differing components of the pulmonary pathophysiology of CLDI. This new information on pulmonary outcomes can assist in designing studies with these parameters. Future studies will be required to evaluate which of the outcomes can better detect improvement with therapeutic intervention and/or lung growth.

Computed tomography and magnetic resonance imaging in cystic fibrosis lung disease

Computed tomography (CT) is the current "gold standard" for assessment of lung morphology and is so far the most reliable imaging modality for monitoring cystic fibrosis (CF) lung disease. CT has a much higher radiation exposure than chest x-ray. The cumulative radiation dose for life-long repeated CT scans has limited its use for CF patients as their life expectancy increases. Clearly, no dose would be preferable over low dose when the same or more relevant information can be obtained. Magnetic resonance imaging (MRI) is comparable to CT with regard to the detection of most morphological changes in the CF lung. It is thought to be less sensitive to detect small airway disease. At the same time, MRI is superior to CT when it comes to the assessment of functional changes such as altered pulmonary perfusion. The recommendation is to further reduce radiation dose related to the use of CT and to use MRI in the follow-up of morphological changes where possible.

Efficacy assessment in paediatric studies

Even though the regulatory authorities to some extent accept the extrapolation of efficacy data from adults to paediatric patients, it is often the case that differences in the disease process and the developmental stage of the children prevent the extrapolation of efficacy in these populations. Where efficacy studies are needed, the development, validation, and employment of different endpoints for specific age and developmental subgroups become necessary. Children are in continuous development and any measure to assess the efficacy of an intervention should take carefully into account how this development affects the endpoints, including the performance capacity of the child and differences in the condition and symptoms presented. Clinical endpoints that are used in the adult trials to evaluate treatment effect may not be suitable in paediatric studies. The development of surrogate endpoints for benefit and risk assessment in children is necessary. Collaboration between the academic researchers, pharmaceutical industry, and regulatory authorities is needed to meet the challenges in proper validation of biomarkers and surrogate endpoints in paediatric trials.

Bronchiectasis and pulmonary exacerbations in children and young adults with cystic fibrosis

OBJECTIVE

Respiratory tract exacerbation rate (RTE-R) is a key clinical efficacy end point in cystic fibrosis (CF) trials. Chest CT scanning holds great potential as a surrogate end point. Evidence supporting the ability of CT scan scores to predict RTE-R is an important step in validating CT scanning as a surrogate end point. The objective of this study was to investigate the association between CT scan scores and RTE-R in a cohort of pediatric patients with CF.

METHODS

A retrospective review of data from pediatric patients with CF included chest CT scans, spirometry, and 2 years follow-up. RTE-R was defined as the number of IV antibiotics courses per year. CT scans were scored with the Brody-II system, assessing bronchiectasis, airway wall thickening, mucus, and opacities.

RESULTS

One hundred fifteen patients contributed 170 CT scans. Median age and FEV(1) at first CT scan were 12 years (range, 5-20 years) and 90% predicted (range, 23% predicted-132% predicted), respectively. Analyzing exacerbation counts using Poisson regression models, bronchiectasis score and FEV(1) both were found to be strong independent predictors of RTE-R in the subsequent 2 years. For the bronchiectasis score categorized in quartiles, RTE-R increased by factors of 1.8 (95% CI, 0.6-6.1; P = .31), 5.5 (95% CI, 1.9-15.4; P = .001), and 10.6 (95% CI, 3.8-29.4; P < .001), respectively, for each quartile compared with the quartile with the best (ie, lowest) scores. Similarly, time to first respiratory tract exacerbation was significantly associated with quartiles of both bronchiectasis score and FEV(1).

CONCLUSIONS

The CT scan bronchiectasis score is strongly associated with RTE-R in pediatric patients with CF, providing an important piece of evidence in the validation of CT scans as an end point for CF clinical trials.

Pulmonary outcome prediction (POP) tools for cystic fibrosis patients

RATIONALE

Loss of lung function in patients with cystic fibrosis (CF) is associated with increased mortality and varies between individuals and over time. Predicting this decline could improve patient management.

OBJECTIVES

To develop simple pulmonary outcome prediction (POP) tools to estimate lung function at age 6 in patients aged 2-5 years (POP(2-5)) and lung function change over a 4-year period in patients aged 6-17 years (POP(6-17)).

METHODS

Analyses were conducted using patients from the Epidemiologic Study of CF (ESCF). To be included in any analysis, patients had to have 1 year of clinical history recorded in ESCF prior to a clinically stable routine Index Clinic Visit (ICV). In addition to this criterion, for the POP(2-5) tool patients had to be between 2 and 5 years old at ICV and have a second clinically stable visit with spirometric measures at age 6. For the POP(6-17) tool, patients had to be between the ages of 6 and 17 years old at an ICV that included spirometric measures and had to have a second clinically stable visit with spirometric measures from 3 to 5 years after ICV. All patients enrolled in ESCF who met these inclusion criteria were studied. POP(2-5) and POP(6-17) populations were further divided into development groups (with ICV before January 1, 1998) and validation groups (with ICV after that date). Development groups were used to model forced expiratory volume in 1 sec (FEV(1)) percent predicted at age 6 years (for POP(2-5)) and annualized FEV(1) % predicted change from ICV to the second visit (for POP(6-17)) by multivariable linear regression using age, sex, weight-for-age percentile, cough, sputum production, clubbing, crackles, wheeze, sinusitis, number of exacerbations requiring intravenous antibiotics in the past year, elevated liver enzymes, pancreatic enzyme use, and respiratory tract culture status, plus height-for-age percentile (POP(2-5)) and index FEV(1) (POP(6-17)). Integer-based POP(2-5) and POP(6-17) tools created from selected variables were evaluated by Pearson correlation and then prospectively validated with separate data collected later from ESCF patients with ICV after January 1, 1998.

MAIN RESULTS

POP(2-5) and POP(6-17) development groups included 2,709 and 6,113 patients and validation groups included 3,458 and 7,086 patients, respectively. Variables retained were weight-for-age percentile, clubbing, crackles, wheeze, number of exacerbations, and Pseudomonas aeruginosa culture status (both tools), daily cough (POP(2-5)), and age, sex, and index FEV(1) % predicted (POP(6-17)). Correlation coefficients for POP(2-5) and POP(6-17) tools prospectively applied to validation groups were +0.32 and +0.37, respectively.

CONCLUSIONS

These simple integer-based POP algorithms employ variables available at clinic visits and can be used to predict the probability of different future pulmonary outcomes for individual patients and patient populations.

Endpoints in respiratory diseases

A wide range of outcome measures or endpoints has been used in clinical trials to assess the effects of treatments in paediatric respiratory diseases. This can make it difficult to compare treatment outcomes from different trials and also to understand whether new treatments offer a real clinical benefit for patients. Clinical trials in respiratory diseases evaluate three types of endpoints: subjective, objective and health-related outcomes. The ideal endpoint in a clinical trial needs to be accurate, precise and reliable. Ideally, the endpoint would also be measured with minimal risk and across all ages, easy to perform, and be inexpensive. As for any other disease, endpoints for respiratory diseases must be viewed in the context of the important distinction between clinical endpoints and surrogate endpoints. The association between surrogate endpoints and clinical endpoints must be clearly defined for any disease in order for them to be meaningful as outcome measures. The most common endpoints which are used in paediatric trials in respiratory diseases are discussed. For practical purposes, diseases have been separated into acute (bronchiolitis, acute viral-wheeze, acute asthma and croup) and chronic (asthma and cystic fibrosis). Further development of endpoints will enable clinical trials in children with respiratory diseases with the main objective of improving prognosis and safety.

Characteristics of orphan drug applications that fail to achieve marketing approval in the USA

The US Orphan Drug Act has fostered the development of drugs for patients with rare diseases by granting 'orphan designations', although several orphan drugs for which a marketing application has been submitted to the FDA have failed to obtain approval. This study identified the clinical trial design, the level of experience of the sponsor and the level of interaction with the FDA to be associated with non-approval. Sponsors, therefore, should engage in dialogue with the FDA and thoughtfully design pivotal clinical trials in accordance with FDA guidance documents.