Phase 3 Open-Label Clinical Trial of Elexacaftor/Tezacaftor/Ivacaftor in Children Aged 2-5 Years with Cystic Fibrosis and at Least One F508del Allele.

Rationale: Elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) has been shown to be safe and effective in people with cystic fibrosis (CF) aged ⩾6 years with at least one F508del-CFTR allele but has not been studied in younger children. Objectives: To evaluate the safety, pharmacokinetics, pharmacodynamics, and efficacy of ELX/TEZ/IVA in children with CF aged 2-5 years. Methods: In this phase 3, open-label, two-part study (parts A and B), children weighing <14 kg (on Day 1) received ELX 80 mg once daily (qd), TEZ 40 mg qd, and IVA 60 mg each morning and 59.5 mg each evening; children weighing ⩾14 kg received ELX 100 mg qd, TEZ 50 mg qd, and IVA 75 mg every 12 hours. Measurements and Main Results: The primary endpoints for part A (15-d treatment period) were pharmacokinetics and safety and tolerability. For part B (24-wk treatment period), the primary endpoint was safety and tolerability; secondary endpoints included pharmacokinetics and absolute changes from baseline in sweat chloride concentration and lung clearance index2.5 (LCI2.5, defined as the number of lung turnovers required to reduce the end tidal N2 concentration to 2.5% of its starting value) through Week 24. Analysis of pharmacokinetic data from 18 children enrolled in part A confirmed the appropriateness of the part B dosing regimen. In part B, 75 children (F508del/minimal function genotypes, n = 52; F508del/F508del genotype, n = 23) were enrolled and dosed. Seventy-four children (98.7%) had adverse events, which were all mild (62.7%) or moderate (36.0%) in severity. The most common adverse events were cough, fever, and rhinorrhea. Decreases in sweat chloride concentration (-57.9 mmol/L; 95% confidence interval [CI], -61.3 to -54.6; n = 69) and LCI2.5 (-0.83 U; 95% CI, -1.01 to -0.66; n = 50) were observed from baseline through Week 24. Mean body mass index was within the normal range at baseline and remained stable at Week 24. Conclusions: In this open-label study in children 2-5 years of age, ELX/TEZ/IVA treatment was generally safe and well tolerated, with a safety profile consistent with that observed in older age groups, and led to clinically meaningful reductions in sweat chloride concentration and LCI2.5. Clinical trial registered with www.clinicaltrials.gov (NCT04537793).

Nasal nitric oxide measurement in children for the diagnosis of primary ciliary dyskinesia: European Respiratory Society technical standard.

Nasal nitric oxide (nNO) is extremely low in most people with primary ciliary dyskinesia (PCD) and its measurement is an important contributor to making the diagnosis. Existing guidelines and technical standards focus on nNO measurements in older, cooperative children using chemiluminescence analysers. However, measurements of nNO in pre-school-age children (age 2-5 years) may facilitate early diagnosis and electrochemical rather than chemiluminescence analysers are widely used. Pre-schoolers often need different methods to be employed when measuring nNO. Hence, a European Respiratory Society Task Force has developed this technical standard as the first step towards standardising sampling, analysis and reporting of nNO measured as part of the diagnostic testing for PCD in all age groups, including pre-school-age children. Furthermore, we considered both chemiluminescence and electrochemical analysers that are in use worldwide. There was a paucity of quality evidence for electrochemical analysers and sampling methods used in young children, and the Task Force proposes future research priorities to allow updates of this technical standard.

Age-related differences in SARS-CoV-2 binding factors: An explanation for reduced susceptibility to severe COVID-19 among children?

CONTEXT: In contrast with other respiratory viruses, children infected with SARS-CoV-2 are largely spared from severe COVID-19. OBJECTIVES: To critically assess age-related differences in three host proteins involved in SARS-CoV-2 cellular entry: angiotensin-converting enzyme 2 (ACE2), transmembrane serine protease 2 (TMPRSS2) and furin. METHODS: We systematically searched Medline, Embase, and PubMed databases for relevant publications. Studies were eligible if they evaluated ACE2, TMPRSS2 or furin expression, methylation, or protein level in children. RESULTS: Sixteen papers were included. Age-dependent differences in membrane-bound and soluble ACE2 were shown in several studies, with ACE2 expression increasing with age. TMPRSS2 and furin are key proteases involved in SARS-CoV-2 spike protein cleavage. TMPRSS2 expression is increased by circulating androgens and is thus low in pre-pubertal children. Furin has not currently been well researched. LIMITATIONS: High levels of study heterogeneity. CONCLUSIONS: Low expression of key host proteins may partially explain the reduced incidence of severe COVID-19 among children, although further research is needed.

Altered airway ciliary orientation in patients with X-linked retinitis pigmentosa.

Previous reports suggested links between respiratory ciliary dysfunction and primary ciliopathies such as X-linked retinitis pigmentosa (XLRP). To investigate if patients with XLRP have abnormal airway ciliary structure or function, we assessed respiratory ciliary beat pattern and ultrastructure, including ciliary orientation, in 12 patients with XLRP without respiratory disease and 10 control subjects. Patients with XLRP had normal ciliary ultrastructure but significantly (p=0.004) increased mean ciliary deviation (33.8°±9.4°) compared with normal subjects (14.8°±5.4°). Altered orientation was associated with impaired ciliary beat pattern in six patients with XLRP. These findings indicate that XLRP mutations, affecting non-motile cilia of the photoreceptors in the retina, can have effects on motile cilia in the respiratory tract. The observation of disrupted ciliary orientation in patients with XLRP is suggestive of a defect in planar cell polarity.

Pulmonary Mycobacterium abscessus complex in children with cystic fibrosis: A practical management guideline.

The treatment of Mycobacterium abscessus complex (MABSC) pulmonary infections is an emerging challenge in patients with cystic fibrosis (CF). Multidrug therapy for prolonged durations is required and carries the significant burden of drug-related toxicity, cost and selective pressure for multiresistant bacteria. International guidelines acknowledge that clinical and in vitro data to support treatment regimens are limited, particularly in children. As part of a collaboration between the infectious diseases and respiratory units at our institution, we have developed a modified treatment guideline that aims to balance the aims of MABSC eradication and slowing disease progression with minimising drug toxicity and resistance. The outcomes of this treatment approach will be monitored and reported. In this manuscript, we discuss the available evidence for treatment choices and present our treatment guideline for paediatric patients with CF and MABSC infection.

The SPEC score-A quantifiable CT scoring system for primary ciliary dyskinesia.

BACKGROUND: Structural lung changes seen on computed tomography (CT) scans in persons with primary ciliary dyskinesia (pwPCD) are currently described using cystic fibrosis (CF) derived scoring systems. Recent work has shown structural changes and frequencies that are unique to PCD, indicating the need for a unique PCD-derived scoring system. METHODS: Chest CT scans from 30 pwPCD, were described for structural changes including bronchiectasis, bronchial wall thickening, mucous plugging, atelectasis, air trapping, and interlobar septal thickening and, additionally, changes previously described as being frequent in pwPCD including extensive tree-in-bud pattern of mucous plugging, bronchoceles or nodules, thickening of interlobar and interlobular septa and whole lobe atelectasis. Based on these findings a novel and unique scoring system, the Specific PCD Evaluation by CT (SPEC) score was constructed. Scans were then re-scored using the SPEC score and results compared to corresponding measurements of lung function to assess structure-function correlation. RESULTS: Total SPEC scores ranged from 0 to 60 (max possible score 90). There was a strong negative correlation between the SPEC score (SPEC) and forced vital capacity (FVC), forced expiratory volume over 1 s (FEV1 ) and FEV1 /FVC ratio (-r = .784, -.865, -.872 respectively). CONCLUSIONS: Using PCD-derived data we describe the construct of a PCD-specific score for assessing lung structural damage on CT scans, the SPEC score. A strong correlation between the SPEC score and PFT variables was identified. The SPEC score holds the potential for describing longitudinal changes in CT scans and assessing the efficacy of interventive therapies in patients with PCD.

Discovery and development of exome-based, co-dominant single nucleotide polymorphism markers in hexaploid wheat (Triticum aestivum L.).

Globally, wheat is the most widely grown crop and one of the three most important crops for human and livestock feed. However, the complex nature of the wheat genome has, until recently, resulted in a lack of single nucleotide polymorphism (SNP)-based molecular markers of practical use to wheat breeders. Recently, large numbers of SNP-based wheat markers have been made available via the use of next-generation sequencing combined with a variety of genotyping platforms. However, many of these markers and platforms have difficulty distinguishing between heterozygote and homozygote individuals and are therefore of limited use to wheat breeders carrying out commercial-scale breeding programmes. To identify exome-based co-dominant SNP-based assays, which are capable of distinguishing between heterozygotes and homozygotes, we have used targeted re-sequencing of the wheat exome to generate large amounts of genomic sequences from eight varieties. Using a bioinformatics approach, these sequences have been used to identify 95 266 putative single nucleotide polymorphisms, of which 10 251 were classified as being putatively co-dominant. Validation of a subset of these putative co-dominant markers confirmed that 96% were true polymorphisms and 65% were co-dominant SNP assays. The new co-dominant markers described here are capable of genotypic classification of a segregating locus in polyploid wheat and can be used on a variety of genotyping platforms; as such, they represent a powerful tool for wheat breeders. These markers and related information have been made publically available on an interactive web-based database to facilitate their use on genotyping programmes worldwide.

Chest computed tomography scores are predictive of survival in patients with cystic fibrosis awaiting lung transplantation.

RATIONALE: Up to one-third of patients with cystic fibrosis (CF) awaiting lung transplantation (LTX) die while waiting. Inclusion of computed tomography (CT) scores may improve survival prediction models such as the lung allocation score (LAS). OBJECTIVES: This study investigated the association between CT and survival in patients with CF screened for LTX. METHODS: Clinical data and chest CTs of 411 patients with CF screened for LTX between 1990 and 2005 were collected from 17 centers. CTs were scored with the Severe Advanced Lung Disease (SALD) four-category scoring system, including the components infection/inflammation (INF), air trapping/hypoperfusion (AT), normal/hyperperfusion (NOR), and bulla/cysts (BUL). The volume of each component was computed using semiautomated software. Survival analysis included Kaplan-Meier curves and Cox regression models. MEASUREMENTS AND MAIN RESULTS: Three hundred and sixty-six (186 males) of 411 patients entered the waiting list (median age, 23 yr; range, 5-58 yr). Subsequently, 67 of 366 (18%) died while waiting, 263 of 366 (72%) underwent LTX, and 36 of 366 (10%) were awaiting LTX at the census date. INF and LAS were significantly associated with waiting list mortality in univariate analyses. The multivariate Cox model including INF and LAS grouped in tertiles, and comparing tertiles 2 and 3 with tertile 1, showed waiting list mortality hazard ratios of 1.62 (95% confidence interval [95% CI], 0.78-3.36; P = 0.19) and 2.65 (95% CI, 1.35-5.20; P = 0.005) for INF, and 1.42 (95% CI, 0.63-3.24; P = 0.40), and 2.32 (95% CI, 1.17-4.60; P = 0.016) for LAS, respectively. These results indicated that INF and LAS had significant, independent predictive value for survival. CONCLUSIONS: CT score INF correlates with survival, and adds to the predictive value of LAS.

Infection, inflammation, and lung function decline in infants with cystic fibrosis.

RATIONALE: Better understanding of evolution of lung function in infants with cystic fibrosis (CF) and its association with pulmonary inflammation and infection is crucial in informing both early intervention studies aimed at limiting lung damage and the role of lung function as outcomes in such studies. OBJECTIVES: To describe longitudinal change in lung function in infants with CF and its association with pulmonary infection and inflammation. METHODS: Infants diagnosed after newborn screening or clinical presentation were recruited prospectively. FVC, forced expiratory volume in 0.5 seconds (FEV(0.5)), and forced expiratory flows at 75% of exhaled vital capacity (FEF(75)) were measured using the raised-volume technique, and z-scores were calculated from published reference equations. Pulmonary infection and inflammation were measured in bronchoalveolar lavage within 48 hours of lung function testing. MEASUREMENTS AND MAIN RESULTS: Thirty-seven infants had at least two successful repeat lung function measurements. Mean (SD) z-scores for FVC were -0.8 (1.0), -0.9 (1.1), and -1.7 (1.2) when measured at the first visit, 1-year visit, or 2-year visit, respectively. Mean (SD) z-scores for FEV(0.5) were -1.4 (1.2), -2.4 (1.1), and -4.3 (1.6), respectively. In those infants in whom free neutrophil elastase was detected, FVC z-scores were 0.81 lower (P=0.003), and FEV(0.5) z-scores 0.96 lower (P=0.001), respectively. Significantly greater decline in FEV(0.5) z-scores occurred in those infected with Staphylococcus aureus (P=0.018) or Pseudomonas aeruginosa (P=0.021). CONCLUSIONS: In infants with CF, pulmonary inflammation is associated with lower lung function, whereas pulmonary infection is associated with a greater rate of decline in lung function. Strategies targeting pulmonary inflammation and infection are required to prevent early decline in lung function in infants with CF.

Persistent pleuritic chest pain in a patient with cystic fibrosis.

Pleural effusion is rare in cystic fibrosis. Infection leading to pleural effusion is likely to be polymicrobial, including contributory fungal infection; microbiology of pleural fluid is commonly discordant with sputum. https://bit.ly/3MJXrhk.

Heparin Inhibits SARS-CoV-2 Replication in Human Nasal Epithelial Cells.

SARS-CoV-2 is the causative agent of the COVID-19 pandemic. Vaccination, supported by social and public health measures, has proven efficacious for reducing disease severity and virus spread. However, the emergence of highly transmissible viral variants that escape prior immunity highlights the need for additional mitigation approaches. Heparin binds the SARS-CoV-2 spike protein and can inhibit virus entry and replication in susceptible human cell lines and bronchial epithelial cells. Primary infection predominantly occurs via the nasal epithelium, but the nasal cell biology of SARS-CoV-2 is not well studied. We hypothesized that prophylactic intranasal administration of heparin may provide strain-agnostic protection for household contacts or those in high-risk settings against SARS-CoV-2 infection. Therefore, we investigated the ability of heparin to inhibit SARS-CoV-2 infection and replication in differentiated human nasal epithelial cells and showed that prolonged exposure to heparin inhibits virus infection. Furthermore, we establish a method for PCR detection of SARS-CoV-2 viral genomes in heparin-treated samples that can be adapted for the detection of viruses in clinical studies.

An international survey on nasal nitric oxide measurement practices for the diagnosis of primary ciliary dyskinesia.

Nasal nitric oxide (nNO) measurements are used in the assessment of patients suspected of having primary ciliary dyskinesia (PCD), but recommendations for performing such measurements have not focused on children and do not include all current practices. To guide the development of a European Respiratory Society-supported technical standard for nNO measurement in children, an international online survey was conducted to better understand current measurement practices among providers involved in PCD diagnostics. 78 professionals responded, representing 65 centres across 18 countries, mainly in Europe and North America. Nearly all centres measured nNO in children and more than half performed measurements before 5 years of age. The test was often postponed in children with signs of acute airway infection. In Europe, the electrochemical technique was more frequently used than chemiluminescence. A similar proportion of centres performed measurements during exhalation against a resistance (49 out of 65) or during tidal breathing (50 out of 65); 15 centres used only exhalation against a resistance and 15 used only tidal breathing. The cut-off values used to discriminate PCD were consistent across centres using chemiluminescence analysers; these centres reported results as an output (nL·min-1). Cut-off values were highly variable across centres using electrochemical devices, and nNO concentrations were typically reported as ppb. This survey is the first to determine real-world use of nNO measurements globally and revealed remarkable variability in methodology, equipment and interpretation. These findings will help standardise methods and training.

Reducing exacerbations in children and adults with primary ciliary dyskinesia using erdosteine and/or azithromycin therapy (REPEAT trial): study protocol for a multicentre, double-blind, double-dummy, 2×2 partial factorial, randomised controlled trial.

INTRODUCTION: Primary ciliary dyskinesia (PCD) is a rare, progressive, inherited ciliopathic disorder, which is incurable and frequently complicated by the development of bronchiectasis. There are few randomised controlled trials (RCTs) involving children and adults with PCD and thus evidence of efficacy for interventions are usually extrapolated from people with cystic fibrosis. Our planned RCT seeks to address some of these unmet needs by employing a currently prescribed (but unapproved for long-term use in PCD) macrolide antibiotic (azithromycin) and a novel mucolytic agent (erdosteine). The primary aim of our RCT is to determine whether regular oral azithromycin and erdosteine over a 12-month period reduces acute respiratory exacerbations among children and adults with PCD. Our primary hypothesis is that: people with PCD who regularly use oral azithromycin and/or erdosteine will have fewer exacerbations than those receiving the corresponding placebo medications. Our secondary aims are to determine the effect of the trial medications on PCD-specific quality-of-life (QoL) and other clinical outcomes (lung function, time-to-next exacerbation, hospitalisations) and nasopharyngeal bacterial carriage and antimicrobial resistance. METHODS AND ANALYSIS: We are currently undertaking a multicentre, double-blind, double-dummy RCT to evaluate whether 12 months of azithromycin and/or erdosteine is beneficial for children and adults with PCD. We plan to recruit 104 children and adults with PCD to a parallel, 2×2 partial factorial superiority RCT at five sites across Australia. Our primary endpoint is the rate of exacerbations over 12 months. Our main secondary outcomes are QoL, lung function and nasopharyngeal carriage by respiratory bacterial pathogens and their associated azithromycin resistance. ETHICS AND DISSEMINATION: Our RCT is conducted in accordance with Good Clinical Practice and the Australian legislation and National Health and Medical Research Council guidelines for ethical conduct of Research, including that for First Nations Australians. TRIAL REGISTRATION NUMBER: ACTRN12619000564156.

Transcript-specific, single-nucleotide polymorphism discovery and linkage analysis in hexaploid bread wheat (Triticum aestivum L.).

Food security is a global concern and substantial yield increases in cereal crops are required to feed the growing world population. Wheat is one of the three most important crops for human and livestock feed. However, the complexity of the genome coupled with a decline in genetic diversity within modern elite cultivars has hindered the application of marker-assisted selection (MAS) in breeding programmes. A crucial step in the successful application of MAS in breeding programmes is the development of cheap and easy to use molecular markers, such as single-nucleotide polymorphisms. To mine selected elite wheat germplasm for intervarietal single-nucleotide polymorphisms, we have used expressed sequence tags derived from public sequencing programmes and next-generation sequencing of normalized wheat complementary DNA libraries, in combination with a novel sequence alignment and assembly approach. Here, we describe the development and validation of a panel of 1114 single-nucleotide polymorphisms in hexaploid bread wheat using competitive allele-specific polymerase chain reaction genotyping technology. We report the genotyping results of these markers on 23 wheat varieties, selected to represent a broad cross-section of wheat germplasm including a number of elite UK varieties. Finally, we show that, using relatively simple technology, it is possible to rapidly generate a linkage map containing several hundred single-nucleotide polymorphism markers in the doubled haploid mapping population of Avalon × Cadenza.

Structural lung disease following allergic bronchopulmonary aspergillosis complicating pediatric cystic fibrosis.

BACKGROUND: Allergic bronchopulmonary aspergillosis (ABPA) complicating cystic fibrosis (CF) is frequently associated with significant structural lung damage as assessed by computed tomography (CT) scanning. METHODS: Using a validated CF scoring system (structural lung disease [SLD] score) we examined the degree of structural lung disease in a group of 25 children with CF who had received steroid therapy for ABPA (CF-ABPA) and compared our findings to a matched group of CF patients without ABPA (CF-CON) using both cross-section and longitudinal analysis. Further, we examined the structure-function correlation between CT findings and lung function. RESULTS: Mean SLD score (expressed as a percentage of maximal score) was significantly higher (worse) in the CF-ABPA group than the CF-CON group (29.3% CF-ABPA vs. 18.7% CF-CON p < .05). CF-ABPA patients showed significantly greater rate of development of structural lung disease over time than CF-CON patients (6.8% per year vs 1.4% p < .01). We found no correlation between lung function and the degree of structural lung disease. CONCLUSIONS: ABPA in children with CF is associated with significantly more structural lung disease than that found in children with CF without ABPA. Despite interventive steroid therapy lung disease progresses more rapidly in those patients with ABPA and CF than control patients with CF.

Airway closure is the predominant physiological mechanism of low ventilation seen on hyperpolarized helium-3 MRI lung scans.

Hyperpolarized helium-3 MRI (3He MRI) provides detailed visualization of low- (hypo- and non-) ventilated lungs. Physiological measures of gas mixing may be assessed by multiple breath nitrogen washout (MBNW) and of airway closure by a forced oscillation technique (FOT). We hypothesize that in patients with asthma, areas of low-ventilated lung on 3He MRI are the result of airway closure. Ten control subjects, ten asthma subjects with normal spirometry (non-obstructed), and ten asthmatic subjects with reduced baseline lung function (obstructed) attended two testing sessions. On visit one, baseline plethysmography was performed followed by spirometry, MBNW, and FOT assessment pre and post methacholine challenge. On visit two, 3He MRI scans were conducted pre and post methacholine challenge. Post methacholine the volume of low-ventilated lung increased from 8.3% to 13.8% in the non-obstructed group (P = 0.012) and from 13.0% to 23.1% in the obstructed group (P = 0.001). For all subjects, the volume of low ventilation from 3He MRI correlated with a marker of airway closure in obstructive subjects, Xrs (6 Hz) and the marker of ventilation heterogeneity Scond with r2 values of 0.61 (P < 0.001) and 0.56 (P < 0.001), respectively. The change in Xrs (6 Hz) correlated well (r2 = 0.45, p < 0.001), whereas the change in Scond was largely independent of the change in low ventilation volume (r2 = 0.13, P < 0.01). The only significant predictor of low ventilation volume from the multi-variate analysis was Xrs (6 Hz). This is consistent with the concept that regions of poor or absent ventilation seen on 3He MRI are primarily the result of airway closure.NEW & NOTEWORTHY This study introduces a novel technique of generating high-resolution 3D ventilation maps from hyperpolarized helium-3 MRI. It is the first study to demonstrate that regions of poor or absent ventilation seen on 3He MRI are primarily the result of airway closure.

Refining diagnostic criteria for paediatric bronchiectasis using low-dose CT scan.

BACKGROUND: There is a current lack of consensus amongst paediatric radiologists and respiratory paediatricians as to the correct CT definition of bronchiectasis in children. Using contemporary low-dose CT, our objectives were to determine the upper limit of normal for broncho-arterial ratio (BAR) in children and to evaluate the effect of age and general anaesthesia. METHODS: Measurements of 330 broncho-arterial ratios from 51 children (0-19 years) undergoing low-dose CT chest for non-respiratory indications were performed by 3 blinded observers (two radiologists, one respiratory physician) using four different methods. Inter-observer reliability, mean BAR and reference ranges (mean±2SD) were calculated. Correlation between age and BARs were examined. Mean BAR for CT under general anaesthesia and CT awake were compared. RESULTS: Inter-observer correlation was extremely high for all measurements (0.93-0.97). There was a weak positive correlation between age and BAR in the CT-awake group (r = 0.33, 95%CI: 0.03-0.57; p = 0.031) using the inner-bronchial wall to artery, short-axis measurement. CT under general anaesthesia showed significantly higher BAR compared to CT-awake [mean difference 0.13 (95%CI: 0.05-0.22; p = 0.004)]. For the CT-awake group, the mean BAR was 0.65 (range: 0.42 to 0.89), with no child having a BAR above 0.9. CONCLUSION: Using a standardised approach, we have shown that a broncho-arterial ratio above 0.9 in children undergoing awake CT is abnormal and suggests airway widening or radiological bronchiectasis. Children undergoing CT under anaesthesia have higher BARs than those undergoing awake CT. A weak positive correlation between broncho-arterial ratio and age was observed, hence, age-adjusted cut-offs for BAR warrant further study.