A randomised trial of oral prednisone for cystic fibrosis pulmonary exacerbation treatment.

BACKGROUND: Elevated markers of systemic and pulmonary inflammation are associated with failure to recover lung function following pulmonary exacerbations in people with cystic fibrosis (pwCF). Our aim was to determine whether adjuvant oral prednisone treatment would improve recovery of forced expiratory volume in 1 s (FEV1) % pred in CF pulmonary exacerbations not responding to antibiotic therapy. METHODS: This was a randomised, double-blind, placebo-controlled trial in pwCF treated with intravenous antibiotics for a pulmonary exacerbation. At day 7, those who had not returned to >90% baseline FEV1 % pred were randomised to adjuvant prednisone 1 mg·kg-1 twice daily (maximum 60 mg·day-1) or placebo for 7 days. The primary outcome was the difference in proportion of subjects who recovered >90% baseline FEV1 % pred at day 14 of i.v. antibiotic therapy. RESULTS: 173 subjects were enrolled, with 76 randomised. 50% of subjects in the prednisone group recovered baseline FEV1 on day 14 compared with 39% of subjects in the placebo group (difference of 11%, 95% CI -11-34%; p=0.34). The mean±sd change in FEV1 % pred from day 7 to day 14 was 6.8±8.8% predicted in the prednisone group and 4.6±6.9% predicted in the placebo group (mean difference 2.2% predicted, 95% CI -1.5-5.9%; p=0.24). Time to subsequent exacerbation was not prolonged in prednisone-treated subjects (hazard ratio 0.83, 95% CI 0.45-1.53; p=0.54). CONCLUSIONS: This study failed to detect a difference in FEV1 % pred recovery between adjuvant oral prednisone and placebo treatment in pwCF not responding at day 7 of i.v. antibiotic therapy for pulmonary exacerbations.

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).

Long-Term Safety and Efficacy of Elexacaftor/Tezacaftor/Ivacaftor in Children Aged ⩾6 Years with Cystic Fibrosis and at Least One F508del Allele: A Phase 3, Open-Label Clinical Trial.

Rationale: A 24-week, phase 3, open-label study showed elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) was safe and efficacious in children aged 6-11 years with cystic fibrosis (CF) and one or more F508del-CFTR alleles. Objectives: To assess long-term safety and efficacy of ELX/TEZ/IVA in children who completed the pivotal 24-week phase 3 trial. Methods: In this phase 3, two-part (part A and part B), open-label extension study, children aged ⩾6 years with CF heterozygous for F508del and a minimal function CFTR mutation (F/MF genotypes) or homozygous for F508del (F/F genotype) who completed the 24-week parent study received ELX/TEZ/IVA based on weight. Children weighing <30 kg received ELX 100 mg once daily/TEZ 50 mg once daily/IVA 75 mg every 12 hours, whereas children weighing ⩾30 kg received ELX 200 mg once daily/TEZ 100 mg once daily/IVA 150 mg every 12 hours (adult dose). The 96-week analysis of part A of this extension study is reported here. Measurements and Main Results: Sixty-four children (F/MF genotypes, n = 36; F/F genotype, n = 28) were enrolled and received one or more doses of ELX/TEZ/IVA. Mean (SD) period of exposure to ELX/TEZ/IVA was 93.9 (11.1) weeks. The primary endpoint was safety and tolerability. Adverse events and serious adverse events were consistent with common manifestations of CF disease. Overall, exposure-adjusted rates of adverse events and serious adverse events (407.74 and 4.72 events per 100 patient-years) were lower than in the parent study (987.04 and 8.68 events per 100 patient-years). One child (1.6%) had an adverse event of aggression that was moderate in severity and resolved after study drug discontinuation. From parent study baseline at Week 96 of this extension study, the mean percent predicted FEV1 increased (11.2 [95% confidence interval (CI), 8.3 to 14.2] percentage points), sweat chloride concentration decreased (-62.3 [95% CI, -65.9 to -58.8] mmol/L), Cystic Fibrosis Questionnaire-Revised respiratory domain score increased (13.3 [95% CI, 11.4 to 15.1] points), and lung clearance index 2.5 decreased (-2.00 [95% CI, -2.45 to -1.55] units). Increases in growth parameters were also observed. The estimated pulmonary exacerbation rate per 48 weeks was 0.04. The annualized rate of change in percent predicted FEV1 was 0.51 (95% CI, -0.73 to 1.75) percentage points per year. Conclusions: ELX/TEZ/IVA continued to be generally safe and well tolerated in children aged ⩾6 years through an additional 96 weeks of treatment. Improvements in lung function, respiratory symptoms, and CFTR function observed in the parent study were maintained. These results demonstrate the favorable long-term safety profile and durable clinical benefits of ELX/TEZ/IVA in this pediatric population. Clinical trial registered with www.clinicaltrials.gov (NCT04183790).

Brain AVM compactness score in children with hereditary hemorrhagic telangiectasia.

OBJECTIVE: The brain arteriovenous malformation (BAVM) nidus compactness score (CS), determined on angiography, predicts BAVM recurrence after surgical resection among children with sporadic BAVMs. We measured the angiographic CS for BAVMs among children with hereditary hemorrhagic telangiectasia (HHT) to determine CS characteristics in this population. METHODS: A pediatric interventional neuroradiologist reviewed angiograms to determine the CS of BAVMs in children with HHT recruited to the BVMC. CS is based on overall nidus and perinidal anomalous vessel compactness. CS categories included 1 = diffuse nidus, 2 = intermediate nidus, and 3 = compact nidus. RESULTS: Forty-eight of 78 children (61.5%) with HHT and brain vascular malformations had a conventional angiogram; 47 (97.9%) angiograms were available. Fifty-four BAVMs were identified in 40 of these 47 children (85.1%). Of 54 BAVMs in children with HHT, CS was 1 in 7 (13%), 2 in 29 (53.7%), and 3 in 18 BAVMs (33.3%) compared with CS of 1 in six (26.1%), 2 in 15 (65.2%), and 3 in 2 BAVMs (8.7%) among 23 previously reported children with sporadic BAVMs, p = 0.045 (Fisher's exact). Seven children with HHT had intracranial hemorrhage: 4 had CS = 3, 1 had CS = 2, and 2 had CS = 1. CONCLUSIONS: A range of CSs exists across HHT BAVMs, suggesting it may be an angiographic measure of interest for future studies of BAVM recurrence and hemorrhage risk. Children with HHT may have more compact niduses compared to children with sporadic BAVMs. Additional research should determine whether CS affects hemorrhage risk or post-surgical recurrence risk in HHT-associated BAVMs, which could be used to direct BAVM treatment.

Evaluation of clinically relevant changes in the lung clearance index in children with cystic fibrosis and healthy controls.

BACKGROUND: The limits of reproducibility of the lung clearance index (LCI) are higher in children with cystic fibrosis (CF) compared with healthy children, and it is currently unclear what defines a clinically meaningful change. METHODS: In a prospective multisite observational study of children with CF and healthy controls (HCs), we measured LCI, FEV1% predicted and symptom scores at quarterly visits over 2 years. Two reviewers performed a detailed review of visits to evaluate the frequency that between visit LCI changes outside ±10%, ±15%, ±20% represented a clinically relevant signal. In the setting of acute respiratory symptoms, we used a generalised estimating equation model, with a logit link function to determine the ability of LCI worsening at different thresholds to predict failure of lung function recovery at follow-up. RESULTS: Clinically relevant LCI changes outside ±10%, ±15% and ±20% were observed at 25.7%, 15.0% and 8.3% of CF visits (n=744), respectively. The proportions of LCI changes categorised as noise, reflecting biological variability, were comparable between CF and HC at the 10% (CF 9.9% vs HC 13.0%), 15% (CF 4.3% vs HC 3.1%) and 20% (CF 2.4% vs HC 1.0%) thresholds. Compared with symptomatic CF visits without a worsening in LCI, events with ≥10% LCI increase were more likely to fail to recover baseline LCI at follow-up. CONCLUSION: The limits of reproducibility of the LCI in healthy children can be used to detect clinically relevant changes and thus inform clinical care in children with CF.

A 3D stack-of-spirals approach for rapid hyperpolarized 129 Xe ventilation mapping in pediatric cystic fibrosis lung disease.

PURPOSE: To demonstrate the feasibility of a rapid 3D stack-of-spirals (3D-SoS) imaging acquisition for hyperpolarized 129 Xe ventilation mapping in healthy pediatric participants and pediatric cystic fibrosis (CF) participants, in comparison to conventional Cartesian multislice (2D) gradient-recalled echo (GRE) imaging. METHODS: The 2D-GRE and 3D-SoS acquisitions were performed in 13 pediatric participants (5 healthy, 8 CF) during separate breath-holds. Images from both sequences were compared on the basis of ventilation defect percent (VDP) and other measures of image similarity. The nadir of transient oxygen saturation (SpO2 ) decline due to xenon breath-holding was measured with pulse oximetry, and expressed as a percent change relative to baseline. RESULTS: 129 Xe ventilation images were acquired in a breath-hold of 1.2-1.8 s with the 3D-SoS sequence, compared to 6.2-8.8 s for 2D-GRE. Mean ± SD VDP measures for 2D-GRE and 3D-SoS sequences were 5.02 ± 1.06% and 5.28 ± 1.08% in healthy participants, and 18.05 ± 8.26% and 18.75 ± 6.74% in CF participants, respectively. Across all participants, the intraclass correlation coefficient of VDP measures for both sequences was 0.98 (95% confidence interval: 0.94-0.99). The percent change in SpO2 was reduced to -2.1 ± 2.7% from -5.2 ± 3.5% with the shorter 3D-SoS breath-hold. CONCLUSION: Hyperpolarized 129 Xe ventilation imaging with 3D-SoS yielded images approximately five times faster than conventional 2D-GRE, reducing SpO2 desaturation and improving tolerability of the xenon administration. Analysis of VDP and other measures of image similarity demonstrate excellent agreement between images obtained with both sequences. 3D-SoS holds significant potential for reducing the acquisition time of hyperpolarized 129 Xe MRI, and/or increasing spatial resolution while adhering to clinical breath-hold constraints.

Inter- and intravisit repeatability of free-breathing MRI in pediatric cystic fibrosis lung disease.

PURPOSE: The purpose of this study is to assess the intra- and interscan repeatability of free-breathing phase-resolved functional lung (PREFUL) MRI in stable pediatric cystic fibrosis (CF) lung disease in comparison to static breath-hold hyperpolarized 129-xenon MRI (Xe-MRI) and pulmonary function tests. METHODS: Free-breathing 1-hydrogen MRI and Xe-MRI were acquired from 15 stable pediatric CF patients and seven healthy age-matched participants on two visits, 1 month apart. Same-visit MRI scans were also performed on a subgroup of the CF patients. Following the PREFUL algorithm, regional ventilation (RVent) and regional flow volume loop cross-correlation maps were determined from the free-breathing data. Ventilation defect percentage (VDP) was determined from RVent maps (VDPRVent ), regional flow volume loop cross-correlation maps (VDPCC ), VDPRVent ∪ VDPCC , and multi-slice Xe-MRI. Repeatability was evaluated using Bland-Altman analysis, coefficient of repeatability (CR), and intraclass correlation. RESULTS: Minimal bias and no significant differences were reported for all PREFUL MRI and Xe-MRI VDP parameters between intra- and intervisits (all P > 0.05). Repeatability of VDPRVent , VDPCC , VDPRVent ∪ VDPCC , and multi-slice Xe-MRI were lower between the two-visit scans (CR = 14.81%, 15.36%, 16.19%, and 9.32%, respectively) in comparison to the same-day scans (CR = 3.38%, 2.90%, 1.90%, and 3.92%, respectively). pulmonary function tests showed high interscan repeatability relative to PREFUL MRI and Xe-MRI. CONCLUSION: PREFUL MRI, similar to Xe-MRI, showed high intravisit repeatability but moderate intervisit repeatability in CF, which may be due to inherent disease instability, even in stable patients. Thus, PREFUL MRI may be considered a suitable outcome measure for future treatment response studies.

Longitudinal Assessment of Curaçao Criteria in Children with Hereditary Hemorrhagic Telangiectasia.

OBJECTIVE: To assess the utility of the Curaçao criteria by age over time in children with hereditary hemorrhagic telangiectasia (HHT). STUDY DESIGN: This was a single-center, retrospective analysis of patients attending the HHT clinic at the Hospital for Sick Children (Toronto, Canada) between 2000 and 2019. The evaluation of the Curaçao criteria was completed during initial and follow-up visits. Screening for pulmonary and brain arteriovenous malformations was completed at 5 yearly intervals. RESULTS: A total of 116 patients with genetic confirmation of HHT were included in the analysis. At initial screening at a median (IQR) age of 8.4 (2.8, 12.9) years, 41% met criteria for a definite clinical diagnosis (≥3 criteria). In children <6 years at presentation, only 23% fulfilled at least 3 criteria initially. In longitudinal follow-up, 63% reached a definite clinical diagnosis, with a median (IQR) follow-up duration of 5.2 (3.2, 7.9) years (P = .005). Specifically, more patients met the epistaxis and telangiectasia criteria at last visit compared with initial (79% vs 60%; P = .006; 47% vs 30%; P = .02) but not for the arteriovenous malformation criterion (59% vs 57%; P = .65). CONCLUSIONS: In the pediatric population, most patients do not meet definite clinical criteria of HHT at initial presentation. Although the number of diagnostic criteria met increased over time, mainly due to new onset of epistaxis and telangiectasia, accuracy remained low during follow-up visits. Relying solely on clinical criteria may lead to underdiagnosis of HHT in children.

Intra- and Inter-visit Repeatability of 129 Xenon Multiple-Breath Washout MRI in Children With Stable Cystic Fibrosis Lung Disease.

BACKGROUND: Multiple-breath washout (MBW) 129 Xe MRI (MBW Xe-MRI) is a promising technique for following pediatric cystic fibrosis (CF) lung disease progression. However, its repeatability in stable CF needs to be established to use it as an outcome measure for novel therapies. PURPOSE: To assess intravisit and intervisit repeatability of MBW Xe-MRI in healthy and CF children. STUDY TYPE: Prospective, longitudinal cohort study. SUBJECTS: A total of 18 pediatric subjects (7 healthy, 11 CF). FIELD STRENGTH/SEQUENCE: A 3 T/2D coronal hyperpolarized (HP) 129 Xe images using GRE sequence. ASSESSMENT: All subjects completed MBW Xe-MRI, pulmonary function tests (PFTs) (spirometry, nitrogen [N2 ] MBW for lung clearance index [LCI]) and ventilation defect percent (VDP) at baseline (visit 1) and 1-month after. Fractional ventilation (FV), coefficient of variation (CoVFV ) maps were calculated from MBW Xe-MRI data acquired between intervening air washout breaths performed after an initial xenon breath-hold. Skewness of FV and CoVFV map distributions was also assessed. STATISTICAL TESTS: Repeatability: intraclass correlation coefficients (ICC), within-subject coefficient of variation (CV%), repeatability coefficient (CR). Agreement: Bland-Altman. For correlations between MBW Xe-MRI, VDP and PFTs: Spearman's correlation. Significance threshold: P < 0.05. RESULTS: For FV, intravisit median [IQR] ICC was high in both healthy (0.94 [0.48, 0.99]) and CF (0.83 [0.04, 0.97]) subjects. CoVFV also had good intravisit ICC in healthy (0.92 [0.42, 0.99]) and CF (0.79 [0.02, 0.96]) subjects. Similarly, for FV, intervisit ICC was high in health (0.94 [0.68, 0.99]) and CF (0.89 [0.61, 0.97]). CoVFV also had good intervisit ICC in health (0.92 [0.42, 0.99]) and CF (0.78 [0.26, 0.94]). FV had better intervisit repeatability than VDP. CoVFV correlated significantly with LCI (R = 0.56). Skewness of FV distributions significantly distinguished between cohorts at baseline. DATA CONCLUSION: MBW Xe-MRI had high intravisit and intervisit repeatability in healthy and stable CF subjects. CoVFV correlated with LCI, suggesting the importance of ventilation heterogeneity to early CF. EVIDENCE LEVEL: 1. TECHNICAL EFFICACY: Stage 2.

Clinical Effectiveness of Elexacaftor/Tezacaftor/Ivacaftor in People with Cystic Fibrosis: A Clinical Trial.

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).

Efficacy and Safety of Elexacaftor/Tezacaftor/Ivacaftor in Children 6 Through 11 Years of Age with Cystic Fibrosis Heterozygous for F508del and a Minimal Function Mutation: A Phase 3b, Randomized, Placebo-controlled Study.

Rationale: The triple-combination regimen elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) was shown to be safe and efficacious in children aged 6 through 11 years with cystic fibrosis and at least one F508del-CFTR allele in a phase 3, open-label, single-arm study. Objectives: To further evaluate the efficacy and safety of ELX/TEZ/IVA in children 6 through 11 years of age with cystic fibrosis heterozygous for F508del and a minimal function CFTR mutation (F/MF genotypes) in a randomized, double-blind, placebo-controlled phase 3b trial. Methods: Children were randomized to receive either ELX/TEZ/IVA (n = 60) or placebo (n = 61) during a 24-week treatment period. The dose of ELX/TEZ/IVA administered was based on weight at screening, with children <30 kg receiving ELX 100 mg once daily, TEZ 50 mg once daily, and IVA 75 mg every 12 hours, and children ⩾30 kg receiving ELX 200 mg once daily, TEZ 100 mg once daily, and IVA 150 mg every 12 hours (adult dose). Measurements and Main Results: The primary endpoint was absolute change in lung clearance index2.5 from baseline through Week 24. Children given ELX/TEZ/IVA had a mean decrease in lung clearance index2.5 of 2.29 units (95% confidence interval [CI], 1.97-2.60) compared with 0.02 units (95% CI, -0.29 to 0.34) in children given placebo (between-group treatment difference, -2.26 units; 95% CI, -2.71 to -1.81; P < 0.0001). ELX/TEZ/IVA treatment also led to improvements in the secondary endpoint of sweat chloride concentration (between-group treatment difference, -51.2 mmol/L; 95% CI, -55.3 to -47.1) and in the other endpoints of percent predicted FEV1 (between-group treatment difference, 11.0 percentage points; 95% CI, 6.9-15.1) and Cystic Fibrosis Questionnaire-Revised Respiratory domain score (between-group treatment difference, 5.5 points; 95% CI, 1.0-10.0) compared with placebo from baseline through Week 24. The most common adverse events in children receiving ELX/TEZ/IVA were headache and cough (30.0% and 23.3%, respectively); most adverse events were mild or moderate in severity. Conclusions: In this first randomized, controlled study of a cystic fibrosis transmembrane conductance regulator modulator conducted in children 6 through 11 years of age with F/MF genotypes, ELX/TEZ/IVA treatment led to significant improvements in lung function, as well as robust improvements in respiratory symptoms and cystic fibrosis transmembrane conductance regulator function. ELX/TEZ/IVA was generally safe and well tolerated in this pediatric population with no new safety findings.

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.

Lung Clearance Index to Track Acute Respiratory Events in School-Age Children with Cystic Fibrosis.

Rationale: The lung clearance index (LCI) is responsive to acute respiratory events in preschool children with cystic fibrosis (CF), but its utility to identify and manage these events in school-age children with CF is not well defined.Objectives: To describe changes in LCI with acute respiratory events in school-age children with CF.Methods: In a multisite prospective observational study, the LCI and FEV1 were measured quarterly and during acute respiratory events. Linear regression was used to compare relative changes in LCI and FEV1% predicted at acute respiratory events. Logistic regression was used to compare the odds of a significant worsening in LCI and FEV1% predicted at acute respiratory events. Generalized estimating equation models were used to account for repeated events in the same subject.Measurements and Main Results: A total of 98 children with CF were followed for 2 years. There were 265 acute respiratory events. Relative to a stable baseline measure, LCI (+8.9%; 95% confidence interval, 6.5 to 11.3) and FEV1% predicted (-6.6%; 95% confidence interval, -8.3 to -5.0) worsened with acute respiratory events. A greater proportion of events had a worsening in LCI compared with a decline in FEV1% predicted (41.7% vs. 30.0%; P = 0.012); 53.9% of events were associated with worsening in LCI or FEV1. Neither LCI nor FEV1 recovered to baseline values at the next follow-up visit.Conclusions: In school-age children with CF, the LCI is a sensitive measure to assess lung function worsening with acute respiratory events and incomplete recovery at follow-up. In combination, the LCI and FEV1 capture a higher proportion of events with functional impairment.

Time to get serious about the detection and monitoring of early lung disease in cystic fibrosis.

Structural and functional defects within the lungs of children with cystic fibrosis (CF) are detectable soon after birth and progress throughout preschool years often without overt clinical signs or symptoms. By school age, most children have structural changes such as bronchiectasis or gas trapping/hypoperfusion and lung function abnormalities that persist into later life. Despite improved survival, gains in forced expiratory volume in one second (FEV1) achieved across successive birth cohorts during childhood have plateaued, and rates of FEV1 decline in adolescence and adulthood have not slowed. This suggests that interventions aimed at preventing lung disease should be targeted to mild disease and commence in early life. Spirometry-based classifications of 'normal' (FEV1≥90% predicted) and 'mild lung disease' (FEV1 70%-89% predicted) are inappropriate, given the failure of spirometry to detect significant structural or functional abnormalities shown by more sensitive imaging and lung function techniques. The state and readiness of two imaging (CT and MRI) and two functional (multiple breath washout and oscillometry) tools for the detection and monitoring of early lung disease in children and adults with CF are discussed in this article.Prospective research programmes and technological advances in these techniques mean that well-designed interventional trials in early lung disease, particularly in young children and infants, are possible. Age appropriate, randomised controlled trials are critical to determine the safety, efficacy and best use of new therapies in young children. Regulatory bodies continue to approve medications in young children based on safety data alone and extrapolation of efficacy results from older age groups. Harnessing the complementary information from structural and functional tools, with measures of inflammation and infection, will significantly advance our understanding of early CF lung disease pathophysiology and responses to therapy. Defining clinical utility for these novel techniques will require effective collaboration across multiple disciplines to address important remaining research questions. Future impact on existing management burden for patients with CF and their family must be considered, assessed and minimised.To address the possible role of these techniques in early lung disease, a meeting of international leaders and experts in the field was convened in August 2019 at the Australiasian Cystic Fibrosis Conference. The meeting entitiled 'Shaping imaging and functional testing for early disease detection of lung disease in Cystic Fibrosis', was attended by representatives across the range of disciplines involved in modern CF care. This document summarises the proceedings, key priorities and important research questions highlighted.

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.

Determinants of lung disease progression measured by lung clearance index in children with cystic fibrosis.

The lung clearance index (LCI) measured by the multiple breath washout (MBW) test is sensitive to early lung disease in children with cystic fibrosis. While LCI worsens during the preschool years in cystic fibrosis, there is limited evidence to clarify whether this continues during the early school age years, and whether the trajectory of disease progression as measured by LCI is modifiable.A cohort of children (healthy and cystic fibrosis) previously studied for 12 months as preschoolers were followed during school age (5-10 years). LCI was measured every 3 months for a period of 24 months using the Exhalyzer D MBW nitrogen washout device. Linear mixed effects regression was used to model changes in LCI over time.A total of 582 MBW measurements in 48 healthy subjects and 845 measurements in 64 cystic fibrosis subjects were available. The majority of children with cystic fibrosis had elevated LCI at the first preschool and first school age visits (57.8% (37 out of 64)), whereas all but six had normal forced expiratory volume in 1 s (FEV1) values at the first school age visit. During school age years, the course of disease was stable (-0.02 units·year-1 (95% CI -0.14-0.10). LCI measured during preschool years, as well as the rate of LCI change during this time period, were important determinants of LCI and FEV1, at school age.Preschool LCI was a major determinant of school age LCI; these findings further support that the preschool years are critical for early intervention strategies.

Second International Guidelines for the Diagnosis and Management of Hereditary Hemorrhagic Telangiectasia.

DESCRIPTION: Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant disease with an estimated prevalence of 1 in 5000 that is characterized by the presence of vascular malformations (VMs). These result in chronic bleeding, acute hemorrhage, and complications from shunting through VMs. The goal of the Second International HHT Guidelines process was to develop evidence-based consensus guidelines for the management and prevention of HHT-related symptoms and complications. METHODS: The guidelines were developed using the AGREE II (Appraisal of Guidelines for Research and Evaluation II) framework and GRADE (Grading of Recommendations Assessment, Development and Evaluation) methodology. The guidelines expert panel included expert physicians (clinical and genetic) in HHT from 15 countries, guidelines methodologists, health care workers, health care administrators, patient advocacy representatives, and persons with HHT. During the preconference process, the expert panel generated clinically relevant questions in 6 priority topic areas. A systematic literature search was done in June 2019, and articles meeting a priori criteria were included to generate evidence tables, which were used as the basis for recommendation development. The expert panel subsequently convened during a guidelines conference to conduct a structured consensus process, during which recommendations reaching at least 80% consensus were discussed and approved. RECOMMENDATIONS: The expert panel generated and approved 6 new recommendations for each of the following 6 priority topic areas: epistaxis, gastrointestinal bleeding, anemia and iron deficiency, liver VMs, pediatric care, and pregnancy and delivery (36 total). The recommendations highlight new evidence in existing topics from the first International HHT Guidelines and provide guidance in 3 new areas: anemia, pediatrics, and pregnancy and delivery. These recommendations should facilitate implementation of key components of HHT care into clinical practice.

Primary care providers' role in newborn screening result notification for cystic fibrosis.

OBJECTIVE: To explore primary care providers' (PCPs') role in result notification for newborn screening (NBS) for cystic fibrosis (CF), given that expanded NBS has increased the number of positive screening test results, drawing attention to the role of PCPs in supporting families. DESIGN: Cross-sectional survey and qualitative interviews. SETTING: Ontario. PARTICIPANTS: Primary care providers (FPs, pediatricians, and midwives) who received a positive CF NBS result for an infant in their practice in the 6 months before the study. MAIN OUTCOME MEASURES: Whether the PCP notified the family of the initial positive CF screening result. RESULTS: Data from 321 PCP surveys (response rate of 51%) are reported, including 208 FPs, 68 pediatricians, and 45 midwives. Interviews were completed with 34 PCPs. Most (65%) surveyed PCPs reported notifying the infant's family of the initial positive screening result; 81% agreed that they have an important role to play in NBS; and 88% said it was important for PCPs, rather than the NBS centre, to notify families of initial positive results. With support and information from NBS centres, 68% would be extremely or very confident in doing so; this dropped to 54% when reflecting on their recent reporting experience. More than half (58%) of all PCPs said written point-of-care information from the NBS centre was the most helpful format. Adjusted for relevant factors, written educational information was associated with a lower rate of notifying families than written plus verbal information (risk ratio of 0.79; 95% CI 0.69 to 0.92). In the interviews, PCPs emphasized the challenge of balancing required content knowledge with the desire for the news to come from a familiar provider. CONCLUSION: Most PCPs notify families of NBS results and value this role. These data are relevant as NBS programs and other genomic services expand and consider ways of keeping PCPs confident and actively involved.

Newborn screening for cystic fibrosis: Role of primary care providers in caring for infants with positive screening results.

OBJECTIVE: To explore primary care providers' (PCPs') preferred roles and confidence in caring for infants receiving a positive cystic fibrosis (CF) newborn screening (NBS) result, as well as management of CF family planning issues, given that expanded NBS has resulted in an increase in positive results. DESIGN: Mailed questionnaire. SETTING: Ontario. PARTICIPANTS: Ontario FPs, pediatricians, and midwives identified by Newborn Screening Ontario as having had an infant with a positive CF NBS result in their practice in the previous 6 months. MAIN OUTCOME MEASURE: Primary care providers' preferred roles in providing well-baby care for infants with positive CF screening results. RESULTS: Overall, 321 of 628 (51%) completed surveys (208 FPs, 68 pediatricians, 45 midwives). For well-baby care for infants confirmed to have CF, 77% of PCPs indicated they would not provide total care (ie, 68% would share care with other specialists and 9% would refer to specialists completely); for infants with an inconclusive CF diagnosis, 50% of PCPs would provide total care, 45% would provide shared care, and 5% would refer to a specialist; for CF carriers, 89% of PCPs would provide total care, 9% would provide shared care, and 2% would refer. Half (54%) of PCPs were extremely or very confident in providing reassurance about CF carriers' health. Only 25% knew how to order parents' CF carrier testing; 67% knew how to refer for prenatal diagnosis. Confidence in reassuring parents about the health of CF carrier children was associated with providing total well-baby care for CF carriers (risk ratio of 1.50; 95% CI 1.14 to 1.97) and infants with an inconclusive diagnosis (risk ratio of 3.30; 95% CI 1.34 to 8.16). CONCLUSION: Most PCPs indicated willingness to treat infants with a range of CF NBS results in some capacity. It is concerning that some indicated CF carriers should have specialist involvement and only half were extremely or very confident about reassuring families about carrier status. This raises issues about possible medicalization of those with carrier status, prompting the need for PCP education about genetic disorders and the meaning of genetic test results.