The effect of inhaled hypertonic saline on lung structure in children aged 3-6 years with cystic fibrosis (SHIP-CT): a multicentre, randomised, double-blind, controlled trial

BACKGROUND

In the Saline Hypertonic in Preschoolers (SHIP) study, inhaled 7% hypertonic saline improved the lung clearance index in children aged 3-6 years with cystic fibrosis, but it remained unclear whether improvement is also seen in structural lung disease. We aimed to assess the effect of inhaled hypertonic saline on chest CT imaging in children aged 3-6 years with cystic fibrosis.

METHODS

Children with cystic fibrosis were enrolled in this multicentre, randomised, double-blind, controlled study at 23 cystic fibrosis centres in Spain, Denmark, the Netherlands, Italy, France, Belgium, the USA, Canada, and Australia. Eligible participants were children aged 3-6 years who were able to cooperate with chest CT imaging and comply with daily nebuliser treatment. Participants were randomly assigned 1:1 to receive inhaled 2 puffs of 100 μg salbutamol followed by 4mL of either 7% hypertonic saline or 0·9% isotonic saline twice per day for 48 weeks. Randomisation was stratified by age in North America and Australia, and by age and country in Europe. Chest CTs were obtained at baseline and 48 weeks and scored using the Perth-Rotterdam Annotated Grid Morphometric Analysis for Cystic Fibrosis (PRAGMA-CF) method. The primary outcome was the difference between groups in the percentage of total lung volume occupied by abnormal airways (PRAGMA-CF %Disease) measured by chest CT at 48 weeks. Analysis was by intention-to-treat. This study is registered with Clinicaltrials.gov, NCT02950883.

FINDINGS

Between May 24, 2016, and Dec 18, 2019, 134 children were assessed for inclusion. 18 patients were excluded (nine had incomplete or unsuccessful chest CT at enrolment visit, two could not comply with CT training, two had acute respiratory infection, two withdrew consent, two for reasons unknown, and one was already on hypertonic saline). 116 participants were enrolled and randomly assigned to hypertonic saline (n=56) or isotonic saline (n=60). 12 patients dropped out of the study (seven in the hypertonic saline group and five in the isotonic saline group). Mean PRAGMA-CF %Disease at 48 weeks was 0·88% (95% CI 0·60-1·16) in the hypertonic saline group and 1·55% (1·25-1·84) in the isotonic saline group (mean difference 0·67%, 95% CI 0·26-1·08; p=0·0092) based on a linear regression model adjusted for baseline %Disease values and baseline age. Most adverse events in both groups were rated as mild, and the most common adverse event in both groups was cough.

INTERPRETATION

Inhaled hypertonic saline for 48 weeks had a positive effect on structural lung changes in children aged 3-6 years with cystic fibrosis relative to isotonic saline. This is the first demonstration of an intervention that alters structural lung disease in children aged 3-6 years with cystic fibrosis.

FUNDING

Cystic Fibrosis Foundation.

Comparative analysis of respiratory symptom scores to detect acute respiratory events in children with cystic fibrosis

BACKGROUND

Patient-reported outcomes (PROs) are important outcome measures in research and clinical practice. This study describes the longitudinal variability the Cystic Fibrosis Questionnaire-Revised (CFQ-R) Respiratory score and the Chronic Respiratory Infection Symptom Score (CRISS), as well as their ability to identify acute respiratory events in children with CF.

METHODS

In this prospective observational study, the parent-proxy (6 -13 years) and self-reported (6-18 years) CFQ-R Respiratory score and CRISS (6-18 years) were measured every 3 months over 2 years. The lung clearance index (LCI) and FEV₁ were also measured. We compared the diagnostic accuracy of the PROs in distinguishing acute respiratory events and clinically stable visits, using the minimal important difference of each PRO as the threshold.

RESULTS

A total of 98 children with CF were included. On average, the symptom scores did not change between clinically stable visits. The positive predictive value (PPV) and negative predictive value (NPV) of a ≥8.5-point worsening in the parent-proxy CFQ-R score to identify acute respiratory events (n=119) (PPV 70.2% and NPV 87.0%) were higher than for the self-reported CFQ-R score (PPV 58.9% and NPV 72.2%). The PPV and NPV of an ≥11-point change in the CRISS for acute respiratory events (n=137) was 56.5% and 79.6%, respectively. The PPV and NPV of all PROs were increased when combined with the LCI and/or FEV₁pp.

CONCLUSION

Symptoms scores differ in their ability to identify acute respiratory events in children with CF; PPV and NPV of all PROs were improved when combined with lung function outcomes.

Non-invasive MR imaging techniques for measuring femoral arterial flow in a pediatric and adolescent cohort

Magnetic Resonance Imaging (MRI) is well‐suited for imaging peripheral blood flow due to its non‐invasive nature and excellent spatial resolution. Although MRI is routinely used in adults to assess physiological changes in chronic diseases, there are currently no MRI‐based data quantifying arterial flow in pediatric or adolescent populations during exercise. Therefore the current research sought to document femoral arterial blood flow at rest and following exercise in a pediatric‐adolescent population using phase contrast MRI, and to present test‐retest reliability data for this method. Ten healthy children and adolescents (4 male; mean age 14.8 ± 2.4 years) completed bloodwork and resting and exercise MRI. Baseline images consisted of PC‐MRI of the femoral artery at rest and following a 5 × 30 s of in‐magnet exercise. To evaluate test‐retest reliability, five participants returned for repeat testing. All participants successfully completed exercise testing in the MRI. Baseline flow demonstrated excellent reliability (ICC = 0.93, p = 0.006), and peak exercise and delta rest‐peak flow demonstrated good reliability (peak exercise ICC = 0.89, p = 0.002, delta rest‐peak ICC = 0.87, p = 0.003) between‐visits. All three flow measurements demonstrated excellent reliability when assessed with coefficients of variance (CV’s) (rest: CV = 6.2%; peak exercise: CV = 7.3%; delta rest‐peak: CV = 7.1%). The mean bias was small for femoral arterial flow. There was no significant mean bias between femoral artery flow visits 1 and 2 at peak exercise. There were no correlations between age or height and any of the flow measurements. There were no significant differences between male and female participants for any of the flow measurements. The current study determined that peripheral arterial blood flow in children and adolescents can be evaluated using non‐invasive phase contrast MRI. The MRI‐based techniques that were used in the current study for measuring arterial flow in pediatric and adolescent patients demonstrated acceptable test‐retest reliability both at rest and immediately post‐exercise.

Lower Airway Nitrogen Oxide Levels in Children with Primary Ciliary Dyskinesia Is Linked to Neutrophilic Inflammation

Treatment of primary ciliary dyskinesia pulmonary exacerbations resulted in an increase in sputum nitric oxide (NO) metabolites and decrease in neutrophilic inflammation. The association between the 2 suggests that neutrophilic inflammation contributes to airway NO deficiency in primary ciliary dyskinesia and that reducing inflammation may lead to improved airway NO homeostasis. TRIAL REGISTRY: ClinicalTrials.gov: NCT01155115.

Effect of lumacaftor-ivacaftor on mucociliary clearance and clinical outcomes in cystic fibrosis: Results from the PROSPECT MCC sub-study

CFTR function is required for normal mucociliary clearance (MCC) and cough-assisted clearance (CC). Lumacaftor-ivacaftor is approved for use in people with cystic fibrosis (CF) carrying two copies of F508del-CFTR. In this observational study performed at four study sites, we characterized the effect of lumacaftor-ivacaftor on mucociliary and cough clearance and related this to other clinical and research endpoints after one month of treatment. Twenty-five adolescents and adults were enrolled. No effect on whole lung MCC was observed, but CC was significantly increased. Sweat chloride improved by 18 mEq/L in this group, indicating a modest restoration of CFTR activity, but no demonstrable change in FEV₁ or lung clearance index was observed. We speculate that the modest effect of lumacaftor-ivacaftor on CFTR function was insufficient to yield an improvement in MCC.

Exercise intolerance in cystic fibrosis-the role of CFTR modulator therapies

Exercise intolerance is common in people with CF (pwCF), but not universal among all individuals. While associated with disease prognosis, exercise intolerance is not simply a reflection of the degree of lung disease. In people with severe CF, respiratory limitations may contribute more significantly to impaired exercise capacity than in those with mild-moderate CF. At all levels of disease severity, there are peripheral factors e.g., abnormal macro- and micro-vascular function that impair blood flow and reduce oxygen extraction, and mitochondrial defects that diminish metabolic efficiency. We discuss advances in understanding the central and peripheral mechanisms underlying exercise intolerance in pwCF. Exploring both the central and peripheral factors that contribute to exercise intolerance in CF can help inform the development of new therapeutic targets, as well as help define prognostic criteria.

Outcomes of Cystic Fibrosis Screening-Positive Infants With Inconclusive Diagnosis at School Age

BACKGROUND AND OBJECTIVES

Cystic fibrosis (CF) screen-positive infants with an inconclusive diagnosis (CFSPID) are infants in whom sweat testing and genetic analysis does not resolve a CF diagnosis. Lack of knowledge about the health outcome of these children who require clinical follow-up challenges effective consultation. Early predictive biomarkers to delineate the CF risk would allow a more targeted approach to these children.

METHODS

Prospective, longitudinal, multicenter, Canada-wide cohort study of CF positive-screened newborns with 1 to 2 cystic fibrosis transmembrane conductance regulator gene variants, of which at least 1 is not known to be CF-causing and/or a sweat chloride between 30 and 59 mmol/L. These were monitored for conversion to a CF diagnosis, pulmonary, and nutritional outcomes.

RESULTS

The mean observation period was 7.7 (95% confidence interval 7.1 to 8.4) years. A CF diagnosis was established for 24 of the 115 children with CFSPID (21%) either because of reinterpretation of the cystic fibrosis transmembrane conductance regulator genotype or because of increase in sweat chloride concentration ≥60 mmol/L. An initial sweat chloride of ≥40 mmol/l predicted conversion to CF on the basis of sweat testing. The 91 remaining children with CFSPID were pancreatic sufficient and showed normal growth until school age. Pulmonary function as well as lung clearance index in a subgroup of children with CFSPID were similar to that of healthy controls.

CONCLUSIONS

Children with CFSPID have good nutritional and pulmonary outcomes at school age, but rates of reclassifying the diagnosis are high. The initial sweat chloride test can be used as a biomarker to predict the risk for CF in CFSPID.

Clinical Effectiveness of Elexacaftor/Tezacftor/Ivacaftor in People with Cystic Fibrosis

Rationale

The cystic fibrosis (CF) modulator drug, elexacaftor/tezacaftor/ivacaftor (ETI), proved highly effective in controlled clinical trials for individuals with at least one F508del allele, which occurs in at least 85% of people with CF.

Objectives

PROMISE is a postapproval study to understand the broad effects of ETI through 30 months’ clinical use in a more diverse U.S. patient population with planned analyses after 6 months.

Methods

Prospective, observational study in 487 people with CF age 12 years or older with at least one F508del allele starting ETI for the first time. Assessments occurred before and 1, 3, and 6 months into ETI therapy. Outcomes included change in percent predicted FEV₁ (ppFEV₁), sweat chloride concentration, body mass index (BMI), and self-reported respiratory symptoms.

Measurements and Main Results

Average age was 25.1 years, and 44.1% entered the study using tezacaftor/ivacaftor or lumacaftor/ivacaftor, whereas 6.7% were using ivacaftor, consistent with F508del homozygosity and G551D allele, respectively. At 6 months into ETI therapy, ppFEV₁ improved 9.76 percentage points (95% confidence interval [CI], 8.76 to 10.76) from baseline, cystic fibrosis questionnaire–revised respiratory domain score improved 20.4 points (95% CI, 18.3 to 22.5), and sweat chloride decreased −41.7 mmol/L (95% CI, −43.8 to −39.6). BMI also significantly increased. Changes were larger in those naive to modulators but substantial in all groups, including those treated with ivacaftor at baseline.

Conclusions

ETI by clinical prescription provided large improvements in lung function, respiratory symptoms, and BMI in a diverse population naive to modulator drug therapy, using existing two-drug combinations, or using ivacaftor alone. Each group also experienced significant reductions in sweat chloride concentration, which correlated with improved ppFEV₁ in the overall study population.

Clinical trial registered with www.clinicaltrials.gov (NCT NCT04038047).

Perspectives on the translation of in-vitro studies to precision medicine in Cystic Fibrosis

Recent strides towards precision medicine in Cystic Fibrosis (CF) have been made possible by patient-derived in-vitro assays with the potential to predict clinical response to small molecule-based therapies. Here, we discuss the status of primary and stem-cell derived tissues used to evaluate the preclinical efficacy of CFTR modulators highlighting both their potential and limitations. Validation of these assays requires correlation of in-vitro responses to in-vivo measures of clinical biomarkers of disease outcomes. While initial efforts have shown some success, this translation requires methodologies that are sensitive enough to capture treatment responses in a CF population that now predominantly has mild lung disease. Future development of in-vitro and in-vivo biomarkers will facilitate the generation of new therapeutics particularly for those patients with rare mutations where clinical trials are not feasible so that in the future every CF patient will have access to effective targeted therapies.

Riociguat for the treatment of Phe508del homozygous adults with cystic fibrosis

BACKGROUND

Riociguat is a first-in-class soluble guanylate cyclase stimulator for which preclinical data suggested improvements in cystic fibrosis transmembrane conductance regulator (CFTR) function.

METHODS

This international, multicenter, two-part, Phase II study of riociguat enrolled adults with cystic fibrosis (CF) homozygous for Phe508del CFTR. Part 1 was a 28-day, randomized, double-blind, placebo-controlled study in participants not receiving CFTR modulator therapy. Twenty-one participants were randomized 1:2 to placebo or oral riociguat (0.5 mg three times daily [tid] for 14 days, increased to 1.0 mg tid for the subsequent 14 days). The primary and secondary efficacy endpoints were change in sweat chloride concentration and percent predicted forced expiratory volume in 1 second (ppFEV₁), respectively, from baseline to Day 14 and Day 28 with riociguat compared with placebo.

RESULTS

Riociguat did not alter CFTR activity (change in sweat chloride) or lung function (change in ppFEV₁) at doses up to 1.0 mg tid after 28 days. The most common drug-related adverse event (AE) was headache occurring in three participants (21%); serious AEs occurred in one participant receiving riociguat (7%) and one participant receiving placebo (14%). This safety profile was consistent with the underlying disease and the known safety of riociguat for its approved indications.

CONCLUSIONS

The Rio-CF study was terminated due to lack of efficacy and the changing landscape of CF therapeutic development. The current study⁠, within its limits of a small sample size, did not provide evidence that riociguat could be a valid treatment option for CF.

CLINICAL TRIAL REGISTRATION NUMBER

NCT02170025.

Unsupervised phenotypic clustering for determining clinical status in children with cystic fibrosis

BACKGROUND

Cystic fibrosis (CF) is a multisystem disease in which the assessment of disease severity based on lung function alone may not be appropriate. The aim of the study was to develop a comprehensive machine-learning algorithm to assess clinical status independent of lung function in children.

METHODS

A comprehensive prospectively collected clinical database (Toronto, Canada) was used to apply unsupervised cluster analysis. The defined clusters were then compared by current and future lung function, risk of future hospitalisation, and risk of future pulmonary exacerbation treated with oral antibiotics. A k-nearest-neighbours (KNN) algorithm was used to prospectively assign clusters. The methods were validated in a paediatric clinical CF dataset from Great Ormond Street Hospital (GOSH).

RESULTS

The optimal cluster model identified four (A-D) phenotypic clusters based on 12 200 encounters from 530 individuals. Two clusters (A and B) consistent with mild disease were identified with high forced expiratory volume in 1 s (FEV₁), and low risk of both hospitalisation and pulmonary exacerbation treated with oral antibiotics. Two clusters (C and D) consistent with severe disease were also identified with low FEV₁. Cluster D had the shortest time to both hospitalisation and pulmonary exacerbation treated with oral antibiotics. The outcomes were consistent in 3124 encounters from 171 children at GOSH. The KNN cluster allocation error rate was low, at 2.5% (Toronto) and 3.5% (GOSH).

CONCLUSION

Machine learning derived phenotypic clusters can predict disease severity independent of lung function and could be used in conjunction with functional measures to predict future disease trajectories in CF patients.

Bronchodilator responsiveness in cystic fibrosis children treated for pulmonary exacerbations

BACKGROUND

Cystic fibrosis (CF) pulmonary exacerbations (PEx) are associated with a significant drop in pulmonary function. The clinical value of measuring bronchodilator (BD) responsiveness during treatment for PEx to monitor or predict recovery of lung function is unclear.

METHODS

A retrospective analysis of spirometry with BD response testing obtained during hospital admissions for PEx in pediatric CF patients. Repeated events were included for patients with BD testing during multiple admissions.

RESULTS

Two hundred forty-nine spirometries with BD testing in 102 patients were completed around Day 7 (Days 4-10) of hospital admission for treatment of CF PEx. Median (IQR) forced expiratory volume in 1 s (FEV₁ ) was 70.6% predicted (58.1, 84.6) before the PEx event (best FEV₁ in 6 months before admission), 54.4% (41.5, 66.9) at admission, 62.3% (48.4, 74.7) around Day 7 of admission and 67.1% predicted (53.8, 78.2) at the end of treatment. BD response around Day 7 correlated poorly with FEV₁ before PEx (r = -.16, p = .02) and did not correlate with recovery to baseline FEV₁ at end of treatment (r = .08, p = .22). Only 23/249 (9%) individual tests had a BD response in FEV₁ of ≥12% and 200 ml. BD response was not related to age or severity of lung disease and led to an immediate change in clinical management in only four cases.

CONCLUSIONS

Significant BD response in CF patients treated for PEx is rare, shows poor correlation with baseline pulmonary function and does not correlate with the recovery of FEV₁ with treatment. These data suggest that routine testing for BD response is not indicated during PEx.