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

Unsupervised home spirometry versus supervised clinic spirometry for respiratory disease: a systematic methodology review and meta-analysis

BACKGROUND

The number of patients completing unsupervised home spirometry has recently increased due to more widely available portable technology and the COVID-19 pandemic, despite a lack of solid evidence to support it. This systematic methodology review and meta-analysis explores quantitative differences in unsupervised spirometry compared with spirometry completed under professional supervision.

METHODS

We searched four databases to find studies that directly compared unsupervised home spirometry with supervised clinic spirometry using a quantitative comparison (e.g. Bland-Altman). There were no restrictions on clinical condition. The primary outcome was measurement differences in common lung function parameters (forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC)), which were pooled to calculate overall mean differences with associated limits of agreement (LoA) and confidence intervals (CI). We used the I2 statistic to assess heterogeneity, the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool to assess risk of bias and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to assess evidence certainty for the meta-analyses. The review has been registered with PROSPERO (CRD42021272816).

RESULTS

3607 records were identified and screened, with 155 full texts assessed for eligibility. We included 28 studies that quantitatively compared spirometry measurements, 17 of which reported a Bland-Altman analysis for FEV1 and FVC. Overall, unsupervised spirometry produced lower values than supervised spirometry for both FEV1 with wide variability (mean difference -107 mL; LoA= -509, 296; I2=95.8%; p<0.001; very low certainty) and FVC (mean difference -184 mL, LoA= -1028, 660; I2=96%; p<0.001; very low certainty).

CONCLUSIONS

Analysis under the conditions of the included studies indicated that unsupervised spirometry is not interchangeable with supervised spirometry for individual patients owing to variability and underestimation.

Management of respiratory tract exacerbations in people with cystic fibrosis: Focus on imaging

Respiratory tract exacerbations play a crucial role in progressive lung damage of people with cystic fibrosis, representing a major determinant in the loss of functional lung tissue, quality of life and patient survival. Detection and monitoring of respiratory tract exacerbations are challenging for clinicians, since under- and over-treatment convey several risks for the patient. Although various diagnostic and monitoring tools are available, their implementation is hampered by the current definition of respiratory tract exacerbation, which lacks objective "cut-offs" for clinical and lung function parameters. In particular, the latter shows a large variability, making the current 10% change in spirometry outcomes an unreliable threshold to detect exacerbation. Moreover, spirometry cannot be reliably performed in preschool children and new emerging tools, such as the forced oscillation technique, are still complementary and need more validation. Therefore, lung imaging is a key in providing respiratory tract exacerbation-related structural and functional information. However, imaging encompasses several diagnostic options, each with different advantages and limitations; for instance, conventional chest radiography, the most used radiological technique, may lack sensitivity and specificity in respiratory tract exacerbations diagnosis. Other methods, including computed tomography, positron emission tomography and magnetic resonance imaging, are limited by either radiation safety issues or the need for anesthesia in uncooperative patients. Finally, lung ultrasound has been proposed as a safe bedside option but it is highly operator-dependent and there is no strong evidence of its possible use during respiratory tract exacerbation. This review summarizes the clinical challenges of respiratory tract exacerbations in patients with cystic fibrosis with a special focus on imaging. Firstly, the definition of respiratory tract exacerbation is examined, while diagnostic and monitoring tools are briefly described to set the scene. This is followed by advantages and disadvantages of each imaging technique, concluding with a diagnostic imaging algorithm for disease monitoring during respiratory tract exacerbation in the cystic fibrosis patient.

Cystic Fibrosis Human Organs-on-a-Chip

Cystic fibrosis (CF) is an autosomal recessive disease caused by mutations in the cystic fibrosis transmembrane regulator (CFTR) gene: the gene product responsible for transporting chloride and bicarbonate ions through the apical membrane of most epithelial cells. Major clinical features of CF include respiratory failure, pancreatic exocrine insufficiency, and intestinal disease. Many CF animal models have been generated, but some models fail to fully capture the phenotypic manifestations of human CF disease. Other models that better capture the key characteristics of the human CF phenotype are cost prohibitive or require special care to maintain. Important differences have been reported between the pathophysiology seen in human CF patients and in animal models. These limitations present significant limitations to translational research. This review outlines the study of CF using patient-derived organs-on-a-chip to overcome some of these limitations. Recently developed microfluidic-based organs-on-a-chip provide a human experimental model that allows researchers to manipulate environmental factors and mimic in vivo conditions. These chips may be scaled to support pharmaceutical studies and may also be used to study organ systems and human disease. The use of these chips in CF discovery science enables researchers to avoid the barriers inherent in animal models and promote the advancement of personalized medicine.

Evaluation of Inflammatory Biomarkers in Iranian Patients with Cystic Fibrosis

Background::

Cystic fibrosis (CF) is an autosomal recessive disease characterized by a progressive and recurrent lung infection.

Objective::

This study aimed to evaluate the levels of pro-inflammatory cytokines and their correlations with lung function in CF patients.

Methods::

A matched case-control study was conducted among 18 CF (children and adults) and 18 control patients (age and gender-matched) who were admitted to Masih Daneshvari Hospital (Tehran, Iran). The controls had no obvious inflammatory lung disease. The samples of bronchoalveolar lavage (BAL) fluid, serum, and sputum of participants were collected to determine concentrations of inflammatory cytokines such as interleukins (IL-8, IL-1β) and tumour necrosis factor- alpha (TNF-α) using enzyme-linked immunosorbent assay (ELISA). Spirometry was applied and functional pulmonary indices [forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1)] were assessed.

Results::

The mean age of CF patients was 15.43 ± 5.970 years (range 4-24). The FVC in a majority of the CF patients (66.7%) was below 60% and only 33.3% of the patients exhibited normal or mild respiratory dysfunction. There were significant differences between FVC and FEV1 measurements before and after bronchoscopy. In addition, IL-8 levels in all three samples (serum, sputum, and BAL) of CF patients and levels of IL-1β and TNF-α in BAL and sputum samples of CF patients were significantly higher than the control group (p<0.001). However, increased cytokine levels were not associated with lung function.

Conclusion::

Increased IL-8 and TNF-α levels seemed to be associated with signs of clinical deterioration and might be useful as diagnostic markers.

Drug development for cystic fibrosis

The first regulatory approval for a drug developed specifically for cystic fibrosis (CF) occurred in 1993, and since then, several other drugs have been approved. Median predicted survival in people with CF in the United States has increased from approximately 30 years to 44.4 years over that same period. Highly effective modulators of the cystic fibrosis transmembrane conductance regulator became available to approximately 90% of people with CF ages 12 years and older in the United States in 2019 and in Europe in 2020. These transformative therapies will surely reduce morbidity and further extend longevity. The drug development pipeline is filled with therapies that address most aspects of CF disease. As survival and CF therapies advance, and the complexity of CF care increases, the process of drug development has become more sophisticated. In addition, detecting meaningful changes in outcome measures has become more difficult as the health status of people with CF improves. Innovative approaches are required to continue to advance drug development in CF. This review provides a general overview of drug development from the preclinical phase through Phase IV. Special considerations with respect to CF are integrated into the discussion of each phase of drug development. As CF care evolves, drug development must continue to evolve as well, until a one-time cure is available to all people with CF.

Antibiotics in Adult Cystic Fibrosis Patients: A Review of Population Pharmacokinetic Analyses

BACKGROUND

Lower respiratory tract infections are common in adult patients with cystic fibrosis (CF) and are frequently caused by Pseudomonas aeruginosa, resulting in chronic lung inflammation and fibrosis. The progression of multidrug-resistant strains of P. aeruginosa and alterations in the pharmacokinetics of many antibiotics in CF make optimal antimicrobial therapy a challenge, as reflected by high between- and inter-individual variability (IIV).

OBJECTIVES

This review provides a synthesis of population pharmacokinetic models for various antibiotics prescribed in adult CF patients, and aims at identifying the most reported structural models, covariates and sources of variability influencing the dose-concentration relationship.

METHODS

A literature search was conducted using the PubMed database, from inception to August 2020, and articles were retained if they met the inclusion/exclusion criteria.

RESULTS

A total of 19 articles were included in this review. One-, two- and three-compartment models were reported to best describe the pharmacokinetics of various antibiotics. The most common covariates were lean body mass and creatinine clearance. After covariate inclusion, the IIV (range) in total body clearance was 27.2% (10.40-59.7%) and 25.9% (18.0-33.9%) for β-lactams and aminoglycosides, respectively. IIV in total body clearance was estimated at 36.3% for linezolid and 22.4% for telavancin. The IIV (range) in volume of distribution was 29.4% (8.8-45.9%) and 15.2 (11.6-18.0%) for β-lactams and aminoglycosides, respectively, and 26.9% for telavancin. The median (range) of residual variability for all studies, using a combined (proportional and additive) model, was 12.7% (0.384-30.80%) and 0.126 mg/L (0.007-1.88 mg/L), respectively.

CONCLUSION

This is the first review that highlights key aspects of different population pharmacokinetic models of antibiotics prescribed in adult CF patients, effectively proposing relevant information for clinicians and researchers to optimize antibiotic therapy in CF.

Evaluating assumptions of definition-based pulmonary exacerbation endpoints in cystic fibrosis clinical trials

BACKGROUND

Cystic fibrosis (CF) pulmonary exacerbations can be serious respiratory events and reduction in exacerbation rate or risk are important efficacy endpoints for CF therapeutic trials. Variability in exacerbation diagnoses and treatment have led drug developers to employ "objective" exacerbation definitions combining antimicrobial treatment (AT) and the presence of ≥4 of 12 respiratory criteria (first published by Fuchs et al. [NEJM 1994;331(10):637-42]). Assumptions underlying this approach have yet to be formally evaluated.

METHODS

Respiratory events (RE) observed during a 48-week trial of ataluren (NCT02139306), a read-through agent for premature nonsense codons, were compared across six exacerbation definitions: any AT, intravenous AT (IVAT), ≥4 Fuchs criteria present, AT plus ≥4 Fuchs criteria, IVAT plus ≥4 Fuchs criteria, and investigator assessment. Fuchs definitions were evaluated by assessing missingness of individual criteria and associations between criteria presence and clinician exacerbation assessment.

RESULTS

Among 751 RE, more than one third had ≥4 Fuchs criteria present but were not assessed as exacerbations by investigators. Data for ≥1 and for 4 Fuchs criteria, respectively, were missing for ~ 90% and >30% of RE. Only 6/12 Fuchs criteria were present more often when investigators assessed RE as exacerbations than when they did not.

CONCLUSIONS

"Objective" definitions have shortcomings inconsistent with their purpose of optimizing exacerbation capture in clinical trials : 1) they capture events clinicians do not consider exacerbations, 2) are prone to data missingness which can bias the likelihood of meeting the definition, and 3) employ criteria that are not associated with investigator assessment of exacerbation.

Building global development strategies for cf therapeutics during a transitional cftr modulator era

As CFTR modulator therapy transforms the landscape of cystic fibrosis (CF) care, its lack of uniform access across the globe combined with the shift towards a new standard of care creates unique challenges for the development of future CF therapies. The advancement of a full and promising CF therapeutics pipeline remains a necessary priority to ensure maximal clinical benefits for all people with CF. It is through collaboration across the global CF community that we can optimize the evaluation and approval process of new therapies. To this end, we must identify areas for which harmonization is lacking and for which efficiencies can be gained to promote ethical, feasible, and credible study designs amidst the changing CF care landscape. This article summarizes the counsel from core advisors across multiple international regions and clinical trial networks, developed during a one-day workshop in October 2019. The goal of the workshop was to identify, in consideration of the highly transitional era of CFTR modulator availability, the drug development areas for which global alignment is currently uncertain, and paths forward that will enable advancement of CF therapeutic development.

The preclinical discovery and development of the combination of ivacaftor + tezacaftor used to treat cystic fibrosis

INTRODUCTION

Cystic Fibrosis (CF) is caused by mutations in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene. The most common mutation, F508del, induces protein misprocessing and loss of CFTR function. The discovery through in vitro studies of the CFTR correctors (i.e. lumacaftor, tezacaftor) that partially rescue the misprocessing of F508del-CFTR with the potentiator ivacaftor is promising in giving an unprecedented clinical benefit in affected patients.

AREAS COVERED

Online databases were searched using key phrases for CF and CFTR modulators. Tezacaftor-ivacaftor treatment has proved to be safer than lumacaftor-ivacaftor, although clinical efficacy is similar. Further clinical efficacy has ensued with the introduction of triple therapy, i.e. applying second-generation correctors, such as VX-569 and VX-445 (elexacaftor) to tezacaftor-ivacaftor. The triple combinations will herald the availability of etiologic therapies for patients for whom no CFTR modulators are currently applied (i.e. F508del/minimal function mutations) and enhance CFTR modulator therapy for patients homozygous for F508del.

EXPERT OPINION

CF patient-derived tissue models are being explored to determine donor-specific response to current approved and future novel CFTR modulators for F508del and other rare mutations. The discovery and validation of biomarkers of CFTR modulation will complement these studies in the long term and in real-life world.

Do patients with cystic fibrosis participating in clinical trials demonstrate placebo response? A meta-analysis

BACKGROUND

Patients' and families' expectation that a cure for cystic fibrosis (CF) will be found is high. In other debilitating conditions, high expectation has been shown to drive a strong placebo response (PR). Therefore, our goal was to evaluate PR on objective continuous outcomes (FEV₁, BMI) and the CF Questionnaire Revised-Respiratory Domain (CFQR-RD) monitored during randomised clinical trials (RCTs) for CF.

METHODS

We conducted a meta-analysis after a systematic review of the literature carried out to identify RCTs with FEV₁, CFQR-RD and BMI as outcome measures. The standardised mean difference (SMD) was calculated to estimate the PR. A meta-regression analysis was conducted to assess other contributing factors on PR such as study design, trial duration, patient age and disease severity.

RESULTS

Out of 289 RCTs found in the search, we identified 61 articles (published from 1987 to 2017) with respectively 59, 17 and 9 reporting FEV₁, CFQR-RD and BMI at the start and at the end of the RCTs. No significant PR was found on FEV₁ or CFQR-RD. However, a small but significant PR was found on BMI SMD, 0.09 (95% CI (0.01; 0.17); p = 0.03).

CONCLUSION

The PR seems higher when measuring BMI. However, it is not clear whether this improvement can be explained by a PR alone.

Cystic Fibrosis Gene Therapy: Looking Back, Looking Forward

Cystic fibrosis (CF) is an autosomal recessive disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene that encodes a cAMP-regulated anion channel. Although CF is a multi-organ system disease, most people with CF die of progressive lung disease that begins early in childhood and is characterized by chronic bacterial infection and inflammation. Nearly 90% of people with CF have at least one copy of the ΔF508 mutation, but there are hundreds of CFTR mutations that result in a range of disease severities. A CFTR gene replacement approach would be efficacious regardless of the disease-causing mutation. After the discovery of the CFTR gene in 1989, the in vitro proof-of-concept for gene therapy for CF was quickly established in 1990. In 1993, the first of many gene therapy clinical trials attempted to rescue the CF defect in airway epithelia. Despite the initial enthusiasm, there is still no FDA-approved gene therapy for CF. Here we discuss the history of CF gene therapy, from the discovery of the CFTR gene to current state-of-the-art gene delivery vector designs. While implementation of CF gene therapy has proven more challenging than initially envisioned; thanks to continued innovation, it may yet become a reality.

Inflammation in cystic fibrosis: An update

Inflammation plays a critical role in cystic fibrosis (CF) lung pathology and disease progression making it an active area of research and important therapeutic target. In this review, we explore the most recent research on the major contributors to the exuberant inflammatory response seen in CF as well as potential therapeutics to combat this response. Absence of functional cystic fibrosis transmembrane conductance regulator (CFTR) alters anion transport across CF airway epithelial cells and ultimately results in dehydration of the airway surface liquid. The dehydrated airway surface liquid in combination with abnormal mucin secretion contributes to airway obstruction and subsequent infection that may serve as a trigger point for inflammation. There is also evidence to suggest that airway inflammation may be excessive and sustained relative to the infectious stimuli. Studies have shown dysregulation of both pro-inflammatory mediators such as IL-17 and pro-resolution mediators including metabolites of the eicosanoid pathway. Recently, CFTR potentiators and correctors have garnered much attention in the CF community. Although these modulators address the underlying defect in CF, their impact on downstream consequences such as inflammation are not known. Here, we review pre-clinical and clinical data on the impact of CFTR modulators on inflammation. In addition, we examine other cell types including neutrophils, macrophages, and T-lymphocytes that express CFTR and contribute to the CF inflammatory response. Finally, we address challenges in developing anti-inflammatory therapies and highlight some of the most promising anti-inflammatory drugs under development for CF.

Lumacaftor/Ivacaftor reduces pulmonary exacerbations in patients irrespective of initial changes in FEV1

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 (ppFEV₁) 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 ppFEV₁ > 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.

Poor recovery from cystic fibrosis pulmonary exacerbations is associated with poor long-term outcomes

RATIONALE

People with CF treated with IV antibiotics for a pulmonary exacerbation (PEx) frequently fail to recover to baseline FEV₁ . The long-term impact of these events has not been studied.

OBJECTIVES

To determine if a patient's spirometric recovery after a PEx is associated with time to next PEx within 1 year, the spirometric recovery after the next PEx, and/or the number of PEx episodes in the next 3 years.

METHODS

We used data from the CF Foundation Patient Registry from 2004 to 2011. We randomly selected one PEx per patient that met inclusion/exclusion criteria. Patients were defined as Non-Responders if their best FEV₁ (in liters) recorded in the 3 months after the PEx was <90% of the best FEV₁ (in liters) in the 6 months before the PEx. We compared Responders and Non-Responders using multivariable regression models.

RESULTS

We randomly chose 13 954 PEx episodes that met inclusion/exclusion criteria. A total of 2 762 (19.8%) patients were classified as Non-Responders. Non-Responders had a shorter median time to the next PEx, 235 (95%CI 218, 252) days, versus >365 days for Responders. Thirty-four percent of Non-Responders at the initial PEx were also Non-Reponders at the next PEx, versus 20% of Responders at the initial PEx. Non-Responders had more PEx episodes over the next 3 years, 4.99 (95%CI 4.84, 5.13), than Responders, 3.46 (95%CI 3.41, 3.51).

CONCLUSIONS

Poor recovery after a PEx is associated with a shorter time to the next PEx, increased risk of poor recovery at a second PEx, and more frequent subsequent PEx treatments.

Rescue therapy within the UK Cystic Fibrosis Registry: An exploration of predictors of intravenous antibiotic use amongst adults with CF

Background and objective

Intravenous (i.v.) antibiotics are needed for rescue when preventative therapy fails to achieve stability among adults with cystic fibrosis (CF). Understanding the distribution of i.v. days can provide insight into the care that adults with CF need. We aim to determine the baseline characteristics that are associated with higher i.v. use, in particular to test the hypothesis that prior‐year i.v. use is associated with future‐year i.v. use.

Methods

This is a cross‐sectional analysis of the 2013–2014 UK CF registry data. Stepwise logistic regression was performed using current‐year i.v. days as the dependent variable, and demographic variables including prior‐year i.v. days as the covariates. Based on these results, study sample was divided into clinically meaningful subgroups using analysis similar to tree‐based method.

Results

Data were available for 4269 adults in 2013 and 4644 adults in 2014. Prior‐year i.v. use was the strongest predictor for current‐year i.v. use followed by forced expiratory volume in 1 s (FEV₁). Adults with high prior‐year i.v. use (>14 days) continued to require high levels of i.v., regardless of FEV₁. Those with high prior‐year i.v. use and FEV₁ ≥70% had higher current‐year i.v. days compared to adults with low prior‐year i.v. use and FEV₁ <40% (28 days, interquartile range (IQR): 11–41 days vs 14 days, IQR: 0–28 days; Mann–Whitney P‐value <0.001 in 2013).

Conclusion

CF people with prior high levels of rescue often continue to need high levels of rescue even if they have good FEV₁. The reasons for this require further investigations.

Intravenous (i.v.) antibiotic is an important treatment option in cystic fibrosis and is also a marker of pulmonary exacerbations. Our study showed that previous‐year i.v. use is a strong predictor of current‐year i.v. use. This finding could help clinicians to identify people most at risk of future exacerbation.

Chest imaging in cystic fibrosis studies: What counts, and can be counted?

BACKGROUND

The dawn of precision medicine and CFTR modulators require more detailed assessment of lung structure in cystic fibrosis (CF) clinical studies. Various imaging markers have emerged and are measurable, but clarity is needed to identify what markers should count for clinical studies. High-resolution chest computed tomography (CT) scoring has yielded sensitive markers for the study of CF disease progression. Once completed, CT scores from ongoing randomized controlled trials can be used to examine relationships between imaging endpoints and therapeutic effectiveness. Similarly, Magnetic Resonance Imaging (MRI) is in development to generate structural as well as functional markers.

RESULTS

The aim of this review is to characterize the role of currently available CT and MRI markers in clinical studies, and to discuss study design, data processing and statistical challenges unique to these endpoints in CF studies. Suggestions to overcome these challenges in CF studies are included.

CONCLUSIONS

To maximize the potential of CT and MRI markers in clinical studies and advance treatment of CF disease progression, efforts should be made to conduct longitudinal randomized controlled trials including these modalities, develop data repositories, promote standardization and conduct reproducible research.

Use of FEV1 in cystic fibrosis epidemiologic studies and clinical trials: A statistical perspective for the clinical researcher

BACKGROUND

Forced expiratory volume in 1s (FEV₁) is an established marker of cystic fibrosis (CF) disease progression that is used to capture clinical course and evaluate therapeutic efficacy. The research community has established FEV₁ surveillance data through a variety of observational data sources such as patient registries, and there is a growing pipeline of new CF therapies demonstrated to be efficacious in clinical trials by establishing improvements in FEV₁.

RESULTS

In this review, we summarize from a statistical perspective the clinical relevance of FEV₁ based on its association with morbidity and mortality in CF, its role in epidemiologic studies of disease progression and comparative effectiveness, and its utility in clinical trials. In addition, we identify opportunities to advance epidemiologic research and the clinical development pipeline through further statistical considerations.

CONCLUSIONS

Our understanding of CF disease course, therapeutics, and clinical care has evolved immensely in the past decades, in large part due to the thoughtful application of rigorous research methods and meaningful clinical endpoints such as FEV₁. A continued commitment to conduct research that minimizes the potential for bias, maximizes the limited patient population, and harmonizes approaches to FEV₁ analysis while maintaining clinical relevance, will facilitate further opportunities to advance CF care.

Considerations for the Conduct of Clinical Trials with Antiinflammatory Agents in Cystic Fibrosis. A Cystic Fibrosis Foundation Workshop Report

Inflammation leads to lung destruction and loss of pulmonary function in patients with cystic fibrosis (CF). Drugs that modulate the cystic fibrosis transmembrane conductance regulator (CFTR) have recently been approved. Although the impact of CFTR modulators on sweat chloride and lung function are exciting, they have not yet demonstrated an effect on inflammation. Therefore, CF antiinflammatory drug development must continue. Unfortunately, the lack of clarity with this process has left investigators and industry sponsors frustrated. The Cystic Fibrosis Foundation established a working group in early 2014 to address this issue. There are many inflammatory processes disrupted in CF, and, therefore, there are many potential targets amenable to antiinflammatory therapy. Regardless of a drug's specific mechanism of action, it must ultimately affect the neutrophil or its products to impact CF. The working group concluded that before bringing new antiinflammatory drugs to clinical trial, preclinical safety studies must be conducted in disease-relevant models to assuage safety concerns. Furthermore, although studies of antiinflammatory therapies must first establish safety in adults, subsequent studies must involve children, as they are most likely to reap the most benefit. The working group also recommended that pharmacokinetic-pharmacodynamic studies and early-phase safety studies be performed before proceeding to larger studies of longer duration. In addition, innovative study designs may improve the likelihood of adequately assessing treatment response and mitigating risk before conducting multiyear studies. Learning from past experiences and incorporating this knowledge into new drug development programs will be instrumental in bringing new antiinflammatory therapies to patients.

IV-treated pulmonary exacerbations in the prior year: An important independent risk factor for future pulmonary exacerbation in cystic fibrosis

BACKGROUND

Single-center analyses have suggested that the number of CF pulmonary exacerbations (PEx) treated with intravenous antibiotics an individual has experienced in the prior year is significantly associated with their future PEx hazard.

METHODS

We studied Prior-year PEx association with future PEx hazard by Cox proportional hazards regression among CF Foundation Patient Registry patients who experienced PEx after Jan 1, 2010.

RESULTS

Among 13,579 patients, those with 1, 2, 3, or ≥4 Prior-year PEx treated with intravenous antibiotics were at 1.8, 2.9, 4.8, and 8.7 higher PEx hazard vs those without (P<.0001). Adjustment with significant demographic and clinical covariates (univariate P≤.0001) reduced Prior-year PEx hazard ratios to 1.6, 2.4, 3.6, and 6.0 (P<.0001). No other covariates had adjusted hazard ratios of >1.7.

CONCLUSIONS

Prior-year PEx strongly associate with future PEx hazard and should be accounted for in prospective trials where treatment-associated change in PEx hazard is an efficacy outcome.

Prevalence and impact of Streptococcus pneumoniae in adult cystic fibrosis patients: a retrospective chart review and capsular serotyping study

Background

Cystic fibrosis (CF) is a genetic disease characterized by complex polymicrobial communities within the lower respiratory tract. S. pneumoniae, while a well-defined pathogen in the general population, has rarely been identified in CF. Furthermore, prevalence studies on Pneumococcus in CF have predominantly focused on the infant and pediatric populations, and outcome data is lacking.

Methods

Through a review of our comprehensive clinical and microbiologic database from a single adult CF center in Canada from 1978–2013 we sought to determine the incidence, prevalence, serotype and clinical impact of Pneumococcus in adults with CF.

Results

Only fifteen of 318 adult CF patients (5%) were ever found to have transient Pneumococcus colonization, and none developed persistent infection although length of carriage varied. As all isolates were stored, capsular serotyping could be performed using a multiplex PCR panel. Capsular serotyping revealed a varied distribution of several serotypes within these isolates. Lung function testing at time of incident Pneumococcus isolation was compared with values before and after isolation and showed no significant reduction in spirometry values, nor was there an increased need for rescue antibacterial therapy.

Conclusion

Within our center, incident Pneumococcus infection is neither common, associated with a disproportionate clinical deterioration nor results in chronic infection.

Treatment and demographic factors affecting time to next pulmonary exacerbation in cystic fibrosis

BACKGROUND

Pulmonary exacerbations (PEx) are important CF clinical events.

METHODS

We studied time to next PEx following intravenous (IV) antibiotic PEx treatment among Cleveland Ohio CF center patients occurring between January 2010 and September 2014. Patient demographics, clinical presentations, and treatments were modeled by Cox proportional hazards regression to identify covariates associated with time to next PEx.

RESULTS

193 patients were treated for PEx; 155 had a subsequent IV-treated PEx. Six covariates were associated with future PEx hazard: number of PEx in the prior year (hazard ratio 25.1 for ≥3 and 4.4 for 1-2 prior-year PEx versus none; P<.0001), IV treatment duration in weeks (1.2; P=.0004), percent hospital treatment (1.1; P=.0018), and chronic inhaled aminoglycosides (2.5; P<.0001), leukotriene modifiers (1.8; P=.0031), and high dose ibuprofen (0.52; P=.0006).

CONCLUSIONS

Time to next PEx was profoundly associated with prior-year PEx, suggestive of high-risk PEx phenotypes that warrant recognition and further study.

Association between the introduction of a new cystic fibrosis inhaled antibiotic class and change in prevalence of patients receiving multiple inhaled antibiotic classes

BACKGROUND

In 2010, aztreonam for inhalation solution joined aminoglycosides and colistimethate as a new cystic fibrosis (CF) chronic inhaled antimicrobial therapy. We studied how the introduction of this new inhaled antibiotic class changed the management of US CF patients.

METHODS

The use of inhaled aminoglycosides, colistimethate, and aztreonam among patients followed in the CF Foundation Patient Registry was analyzed by age group, lung disease stage, and microbiologic status both annually, and at individual visits between 2009 and 2012.

RESULTS

The overall prevalence of inhaled antibiotic use did not change during the period, but the prevalence of annual and any visit treatment with >1 inhaled antibiotic class more than doubled. Adults, those with advanced lung disease, and those with >1 Pseudomonas aeruginosa respiratory culture were more likely to receive >1 antibiotic class.

CONCLUSIONS

Inhaled antibiotic management of US CF patients has dramatically changed in association with the introduction of a third inhaled antibiotic class.

Improvements in lung function and height among cohorts of 6-year-olds with cystic fibrosis from 1994 to 2012

OBJECTIVE

To characterize spirometry and height changes in cohorts of 6-year-old children with cystic fibrosis (CF).

STUDY DESIGN

Global Lung Initiative forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and FEV1/FVC, and the Centers for Disease Control and Prevention height-for-age (HFA) z-scores were generated for 6-year-old children from the Cystic Fibrosis Foundation Patient Registry each year between 1994 and 2012. Z-score mean differences were analyzed by the t test, and time trends of means were analyzed by least squares regression for all children and for subgroups of sex, F508del mutation genotype, Medicaid insurance, and prenatal/newborn screening identification. Z-score distributions were compared using the 2-sample Kolmogorov-Smirnov test.

RESULTS

A total of 11 670 children with CF were studied, of whom 50.5% were males, 50.2% had the F508del/F508del genotype, and 46.6% were insured by Medicaid. Mean HFA, FEV1, and FVC z-scores increased significantly over the period in the entire cohort and in all subgroups (P < .001), but FEV1/FVC z-scores were below normal and did not change significantly. In 2012, children identified by screening had significantly higher mean HFA (P = .002), FEV1 (P < .001), and FVC (P < .001) z-scores compared with children not screened, with 90% of FVC and 71.4% of FEV1z-scores greater than predicted by the normal distribution. FEV1/FVC z-scores were not different between the children who were and were not screened.

CONCLUSION

Consistent, significant increases in HFA, FEV1, and FVC occurred between 1994 and 2012, but FEV1/FVC, a measure of airway obstruction, did not change appreciably during this period. FVC and FEV1z-score distributions suggest that normative equation reference populations underpredict lung volumes of children with CF, but the reasons for this remain unclear.

State of progress in treating cystic fibrosis respiratory disease

Since the discovery of the gene associated with cystic fibrosis (CF), there has been tremendous progress in the care of patients with this disease. New therapies have entered the market and are part of the standard treatment of patients with CF, and have been associated with marked improvement in survival. Now there are even more promising therapies directed at different components of the pathophysiology of this disease. In this review, our current knowledge of the pathophysiology of lung disease in patients with CF is described, along with the current treatment of CF lung disease, and the therapies in development that offer great promise to our patients.