Worldwide rates of diagnosis and effective treatment for cystic fibrosis

Burkholderia cepacia complex in cystic fibrosis: critical gaps in diagnosis and therapy

Burkholderia cepacia complex (Bcc) is a bacterial group with 'natural' multi-antimicrobial resistance. This complex has generated epidemic outbreaks across the world. In people with cystic fibrosis (CF), Bcc can cause severe lung infections that lead to accelerated lung damage, which can be complicated by necrotizing pneumonia accompanied by high fevers, leucocytosis, and bacteraemia, which commonly causes fatal outcomes. Specifically, infection by Burkholderia cenocepacia is considered an exclusion criterion for lung transplantation. The species of Bcc exhibit both genetic and phenotypic hypervariability that complicate their accurate microbiological identification. Automated methods such as MALDI-TOF can err in the determination of species. Their slow growth even in selective agars and the absence of international consensuses on the optimal conditions for their isolation make early diagnosis a difficult challenge to overcome. The absence of correlations between antibiograms and clinical results has resulted in the absence of standardized cut-off values of antimicrobial susceptibility, a fact that brings a latent risk since incorrect antibiotic therapy can induce the selection of more aggressive variants that worsen the clinical picture of the host, added to the absence of a clear therapeutic guide for the eradication of pulmonary infections by Bcc in patients with CF, resulting in frequently ineffective treatments. There is an urgent need to standardize methods and diagnostic tools that would allow an early and accurate diagnosis, as well as to perform clinical studies of the effectiveness of available antibiotics to eradicate Bcc infections, which would allow us to establish standardized therapeutic schemes for Bcc-infected patients.

CFTR mutations and phenotypic correlations in people with cystic fibrosis: a retrospective study from a single centre in south India

Background

Emerging data reveal higher-than-expected prevalence of cystic fibrosis (CF) among non-European populations worldwide including in the Indian subcontinent. Systematic analyses of the CFTR mutation profile, and genotype-phenotype correlations among people with CF from south, east, or northeast India have not been reported before. We wanted to identify CFTR mutations in people with CF, and highlight novel variants, selective phenotypic correlations, and regional variances within India.

Methods

A retrospective study was conducted at Christian Medical College, Vellore, India (single tertiary referral hospital) from September 2010 to August 2022, involving 120 people with CF from (i) four south Indian states (Tamil Nadu, Andhra Pradesh, Kerala, Karnataka), (ii) in and nearby regions of West Bengal, India and (iii) Bangladesh. Comprehensive CFTR mutation analyses were done by Next-Generation Sequencing, and variants were categorized per American College of Medical Genetics guidelines and compared with validated Locus-specific databases. Demographic characteristics, mutation profile, novel mutations, selective phenotype correlations, and regional variances were assessed.

Findings

In 120 people with CF, 55 CFTR variants were identified, including six novel variants. F508del was the predominant mutation, yet with a lower allele frequency than reported among European populations (27% versus 70%). Phenotypic correlations suggested high mutational pathogenicity causing severe multi-organ morbidity, and death in 27%. Milder variants associated with pancreatic sufficiency were also evident in 23% of people with CF. Statistically significant regional variances were noted in genotype frequency, and clinical phenotype among people with CF from the two regions. Hotspot exons and introns that could potentially help create targeted mutation panels were identified.

Interpretation

The identification of 55 different CFTR variants among 120 people with CF describes the diversity of mutations noted in India, while also revealing the challenges that providers may encounter in timely diagnosis and treatment of CF. However, these single-centre data have specific limitations and cannot be generalised to all people with CF from India or to those of non-European origin. Our data on regional CFTR mutations contribute to the emerging national registry on CF epidemiology in India, help formulate diagnostic and newborn screening algorithms, help optimise clinical care, and highlight urgency to improve access to life-changing modulator therapy.

Funding

Cystic Fibrosis Foundation, USA (towards the CF-India Demonstration Project) and Christian Medical College, Vellore, India.

Oral health and related outcomes in children and adolescents with cystic fibrosis: a scoping review

PURPOSE

Good oral health is important for children and adolescents with cystic fibrosis (CF). The purpose of this scoping review is to describe the existing evidence base regarding oral health in children and adolescents with CF and provide recommendations for future research.

METHODS

Using a scoping review framework, a comprehensive search was undertaken using medline, embase, and PubMed. The search strategy included broad terms relating to CF, oral health, and children and adolescents and included only papers written in English.

RESULTS

61 articles were included. Topics investigated included dental caries, enamel defects, periodontal health, dental staining, oral health related quality of life, dental management, and dental development of children and adolescents with CF.

CONCLUSION

Dental outcomes of children and adolescents with CF differ from the healthy population. The current literature describing dental health in children and adolescents with CF includes predominately descriptive analyses. A shift to hypothesis-based studies to explore causal relationships that explain the differences in dental outcomes seen in the CF population offers an opportunity to better understand the problems faced by children and adolescents with CF. Research that actively engages stakeholders, including children and adolescents with CF and their families will enable evidence-based recommendations to improve their oral health.

Systematic optimization of prime editing for the efficient functional correction of CFTR F508del in human airway epithelial cells

Prime editing (PE) enables precise and versatile genome editing without requiring double-stranded DNA breaks. Here we describe the systematic optimization of PE systems to efficiently correct human cystic fibrosis (CF) transmembrane conductance regulator (CFTR) F508del, a three-nucleotide deletion that is the predominant cause of CF. By combining six efficiency optimizations for PE-engineered PE guide RNAs, the PEmax architecture, the transient expression of a dominant-negative mismatch repair protein, strategic silent edits, PE6 variants and proximal 'dead' single-guide RNAs-we increased correction efficiencies for CFTR F508del from less than 0.5% in HEK293T cells to 58% in immortalized bronchial epithelial cells (a 140-fold improvement) and to 25% in patient-derived airway epithelial cells. The optimizations also resulted in minimal off-target editing, in edit-to-indel ratios 3.5-fold greater than those achieved by nuclease-mediated homology-directed repair, and in the functional restoration of CFTR ion channels to over 50% of wild-type levels (similar to those achieved via combination treatment with elexacaftor, tezacaftor and ivacaftor) in primary airway cells. Our findings support the feasibility of a durable one-time treatment for CF.

Efficacy and safety of LAU-7b in a Phase 2 trial in adults with cystic fibrosis

BACKGROUND

Lung inflammation is associated with tissue damage in cystic fibrosis (CF). LAU-7b, a novel oral drug candidate, was shown to control inflammation and stabilize CFTR protein in the epithelial membrane during inflammatory stress in preclinical models of CF.

METHODS

A double-blind, randomized, placebo-controlled Phase 2 study was conducted to evaluate efficacy and safety of LAU-7b in adults with CF. LAU-7b or placebo was administered over 24 weeks as six 21-day treatment cycles each separated by 7 days. The primary efficacy endpoint was the absolute change from baseline in percent predicted forced expiratory volume in 1 second (ppFEV1) at 24 weeks.

RESULTS

A total of 166 subjects received at least one dose of study drug (Intent-To-Treat population, ITT), of which 122 received ≥5 treatment cycles (Per-Protocol population, PP). Both treatment arms showed a mean lung function loss at 24 weeks of 1.18 ppFEV1 points with LAU-7b and 1.95 ppFEV1 with placebo, a 0.77 ppFEV1 (40 s) difference, p=0.345, and a 0.95 ppFEV1 (49 %) difference in the same direction in PP population, p=0.263. Primary analysis of mean ppFEV1 through 24 weeks showed differences of 1.01 and 1.23 ppFEV1, in the ITT (65 % less loss, p=0.067) and PP populations (78 % less loss, reaching statistical significance p=0.049), respectively. LAU-7b had an acceptable safety profile.

CONCLUSION

Although the study did not meet its primary efficacy endpoint in the ITT population, LAU-7b was generally well tolerated and showed evidence of preservation of lung function to support further development.

Antibacterial potential of Stenotrophomonas maltophilia complex cystic fibrosis isolates

Over 160,000 people worldwide suffer from cystic fibrosis (CF), a genetic condition that causes mucus to accumulate in internal organs. Lung decline is a significant health burden for people with CF (pwCF), and chronic bacterial pulmonary infections are a major cause of death. Stenotrophomonas maltophilia complex (Smc) is an emerging, multidrug-resistant CF pathogen that can cause pulmonary exacerbations and result in higher mortality. However, little is known about the antagonistic interactions that occur between Smc isolates from pwCF and competitor bacteria. We obtained 13 Smc isolates from adult and pediatric pwCF located in the United States or Australia. We co-cultured these isolates with Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli. We also performed whole-genome sequencing of these Smc isolates and compared their genomes using average nucleotide identity analyses. We observed that some Smc CF isolates can engage in antagonistic interactions with P. aeruginosa and S. aureus but recovered a substantial number of P. aeruginosa and S. aureus cells following co-cultures with all tested Smc isolates. By contrast, we discovered that most Smc CF isolates display strong antibacterial properties against E. coli cells and reduce recovery below detectable limits. Finally, we demonstrate that Smc CF strains from this study belong to diverse phylogenetic lineages.

IMPORTANCE

Antagonism toward competitor bacteria may be important for the survival of Stenotrophomonas maltophilia complex (Smc) in external environments, for the elimination of commensal species and colonization of upper respiratory tracts to enable early infections, and for competition against other pathogens after establishing chronic infections. These intermicrobial interactions could facilitate the acquisition of Smc by people with cystic fibrosis from environmental or nosocomial sources. Elucidating the mechanisms used by Smc to eliminate other bacteria could lead to new insights into the development of novel treatments.

Impact of elexacaftor/tezacaftor/ivacaftor CFTR modulator therapy on rates of endoscopic sinus surgery in cystic fibrosis

BACKGROUND

Elexacaftor/tezacaftor/ivacaftor (ETI), a combination cystic fibrosis transmembrane receptor (CFTR) modulator, has demonstrated improved pulmonary outcomes in individuals with cystic fibrosis (CF). However, ETI's impact on functional endoscopic sinus surgery (FESS) remains unclear.

METHODS

The TriNetX Analytics Research Network, consisting of 120 million global de-identified electronic medical records, was queried from 2012 to 2023 for subjects with CF who underwent sinus surgery.1 Patients on ETI prior to FESS (n = 6,056) were propensity score matched to control individuals with CF not on CFTR modulators (n = 37,906) and those on other FDA-approved CFTR modulators (tezacaftor/ivacaftor, lumacaftor/ivacaftor, and ivacaftor) (n = 2437) based on relevant factors. The primary outcome was the absolute risk reduction (ARR) of undergoing FESS. Secondary outcomes included ARR of CF-related pulmonary exacerbations and hospital admission from 0 to 6, 6 to 12, and 12 to 24 months following FESS.

RESULTS

ETI use demonstrated a significant ARR for FESS when compared to CF patients not on CFTR modulators (2.12%; 95% confidence interval [CI] 1.5-2.75; p-value < 0.0001) and those on other CFTR modulators (4.7%; 95% CI 3.54-5.85; p-value < 0.0001). No significant differences occurred in secondary outcomes between ETI and non-CFTR modulator groups, except for reduced CF-related pulmonary exacerbations from 0 to 6 months post-FESS. Additionally, a significant reduction in pulmonary exacerbations was observed at all time points and hospital admissions within 6 months following FESS compared to those using other CFTR modulators.

CONCLUSIONS

In a large dataset, CF patients on ETI demonstrated significantly reduced risk of FESS, pulmonary exacerbations, and hospital admission compared to patients not on CFTR modulators or those on other CFTR modulators, suggesting improved sinonasal disease and overall health status in CF.

Self-care deficits reported by school children with cystic fibrosis

BACKGROUND

Self-care refers to the ability that an individual has or develops to regulate the functioning of the body. Health status and age are factors associated with dependency on, and the need for, someone else to take over self-care. In the present case, there was a self-care deficit. Cystic fibrosis is a chronic disease that occurs in one in 10,000 live births in Brazil, and the affected population in the country is predominantly pediatric (approximately 73%). Support from nursing teams is necessary to improve patients' skills until they can take full responsibility for their self-care.

PURPOSE

This study aimed to identify self-care deficits based on reports from schoolchildren with cystic fibrosis.

DESIGN AND METHOD

A qualitative study was conducted with eight Brazilian schoolchildren with cystic fibrosis, using an art-based technique during interviews. Minayo's thematic analysis was used for data analysis and interpretation.

RESULTS

These results emerged from Orem's theory of self-care deficits and needs. A main theme labeled as universal self-care requisites was identified, and three subthemes were derived-maintenance of an adequate air supply; maintenance of a balance between activity and rest; and avoiding risks to life, bodily functions, and well-being.

CONCLUSION

Schoolchildren living with cystic fibrosis have a negative attitude toward their disease, which makes it difficult for them to acquire the ability to care for themselves with greater autonomy. This leads to deficits in the self-care delivered by providers.

IMPLICATIONS TO PRACTICE

It is necessary to recognize the deficits in self-care and the extent to which children living with cystic fibrosis depend on self-care providers. Families must be aware of these self-care deficits to develop holistic self-care abilities.

A Longitudinal Study of Adherence among Cystic Fibrosis Patients: Associations with Gratitude Over the Course of One Year

BACKGROUND

Daily airway clearance therapy (ACT) is a critical aspect of treatment in cystic fibrosis (CF), but poor adherence is a prominent concern. Identifying factors that might enhance or diminish adherence is a priority for treatment centers. Gratitude, a generalized tendency to notice and appreciate positive facets of experience, is a psychosocial resource that has commanded growing research interest. This longitudinal study examined whether gratitude at baseline was associated with ongoing or persistent ACT adherence over the course of a year.

METHODS

Trait gratitude was evaluated at baseline using a validated measure, among adults receiving care at a regional CF treatment center. Self-reported adherence to ACT was assessed at baseline, 6 months, and 12 months using the Cystic Fibrosis Treatment Questionnaire. Average age of participants was 27.2 years, 45.5% were women, and 19.7% had severe disease.

RESULTS

In multivariable logistic regression models that accounted for disease severity (Forced Expiratory Volume1% predicted) and other clinical and demographic variables, individuals with higher baseline gratitude were significantly more likely to demonstrate persistent adherence over the course of the year. Gratitude remained predictive after additionally adjusting for other well-known psychosocial resource variables (social support and emotional well-being).

CONCLUSION

This is among the first demonstrations that gratitude is associated with persistent self-reported adherence to treatment over time. Findings suggest that gratitude may be important psychosocial resource for adults with CF, as they contend with complex, highly burdensome treatment regimens. Further research is warranted to examine these relationships and their impact on downstream health outcomes.

Evolution of nutritional management in children with cystic fibrosis - a narrative review

Nutrition has played a central role in the management and outcomes of people with cystic fibrosis (pwCF) since the 1970s. Advances in therapies and practices in recent decades have led to a significant change in the patient landscape with dramatic improvements in life expectancy, as well as quality of life, bringing with it new issues. Historically, cystic fibrosis was a condition associated with childhood and malnutrition; however, changes in patient demographics, nutritional assessment and fundamental nutritional management have evolved, and it has become an increasingly prevalent adult disease with new nutritional challenges, including obesity. This paper aims to describe these changes and the impact and challenges they bring for those working in this field. Nutritional professionals will need to evolve, adapt and remain agile to the wider range of situations and support required for a new generation of pwCF. Specialised nutrition support will continue to be required, and it will be additionally important to improve and optimise quality of life and long-term health.

International disparities in diagnosis and treatment access for cystic fibrosis

BACKGROUND

Elexacaftor/tezacaftor/ivacaftor (ETI) has revolutionized cystic fibrosis (CF) treatment. However, previous research has demonstrated profound global disparities in diagnosis and treatment access. If unaddressed, these threaten to widen existing health inequities. Therefore, in this analysis we aimed to reappraise gaps and evaluate progress in diagnosis and treatment equity in high-income (HIC) versus low- and middle-income countries (LMICs).

METHODS

Estimates of the global CF population were made in 158 countries using patient registries, systematic literature searches, and an international survey of 14 CF experts. Estimates of the global burden of undiagnosed CF were made using epidemiological studies identified in literature searches and registry coverage data. The proportion of people receiving ETI was estimated using publicly available revenue data and a survey of 23 national drug pricing databases.

RESULTS

188,336 (163,421-209,204) people are estimated to have CF in 96 countries. Of these, 111,767 (59%) were diagnosed and 51,322 (27%) received ETI. The undiagnosed patient burden is estimated to be 76,569 people, with 82% in LMICs. ETI is reimbursed in 35 HICs, but only one LMIC. Four years after approval, there are 13,723 people diagnosed with CF who live in a country where ETI is inaccessible. This increases to 76,199 when including the estimated undiagnosed population.

CONCLUSIONS

Equitable access to CFTR modulators must become a top priority for the international CF community. ETI costs up to $322,000 per year but could be manufactured for $5000 to allow access under a voluntary license. Given the extent of disparities, other mechanisms to improve access that circumvent the manufacturer should also be considered.

Comparison of clinical features of cystic fibrosis patients eligible but not on CFTR modulators to ineligible for CFTR modulators

INTRODUCTION

Cystic fibrosis transmembrane conductance regulator (CFTR) modulator drugs target the underlying defect and improve CFTR function. They are a part of standard care in many countries, but not all patients are eligible for these drugs due to age and genotype. Here, we aimed to determine the characteristics of non-eligible patients for CFTR modulators in the CF registry of Turkey (CFRT) to highlight their clinical needs.

METHODS

This retrospective cohort study included CF patient data from the CFRT in 2021. The decision of eligibility for the CFTR modulator was determined according to the 'Vertex treatment-Finder' on the Vertex® website. Demographic and clinical characteristics of patients were compared between eligible (group 1) and ineligible (group 2) groups for CFTR modulators.

RESULTS

Among the study population (N = 1527), 873 (57.2%) were in group 1 and 654 (42.8%) were in group 2. There was no statistical difference between groups regarding sex, meconium ileus history, diagnoses via newborn screening, FEV1 z-score, CF-associated complications, organ transplant history, and death. Patients in group 2 had a higher incidence of pancreatic insufficiency (87.7% vs. 83.2%, p = .010), lower median height z-scores (-0.87 vs. -0.55, p < .001), lower median body mass index z-scores (-0.65 vs. -0.50, p < .001), longer days receiving antibiotics due to pulmonary exacerbation (0 [interquartile range, IQR: 0-2] vs. 0 [IQR: 0-7], p = 0.001), and more non-invasive ventilation support (2.6% vs. 0.9%, p = 0.008) than patients in group 1.

CONCLUSION

The ineligible group had worse clinical outcomes than the eligible group. This highlights their need for life-changing drugs to improve clinical outcomes.

Prime editing functionally corrects cystic fibrosis-causing CFTR mutations in human organoids and airway epithelial cells

Prime editing is a recent, CRISPR-derived genome editing technology capable of introducing precise nucleotide substitutions, insertions, and deletions. Here, we present prime editing approaches to correct L227R- and N1303K-CFTR, two mutations that cause cystic fibrosis and are not eligible for current market-approved modulator therapies. We show that, upon DNA correction of the CFTR gene, the complex glycosylation, localization, and, most importantly, function of the CFTR protein are restored in HEK293T and 16HBE cell lines. These findings were subsequently validated in patient-derived rectal organoids and human nasal epithelial cells. Through analysis of predicted and experimentally identified candidate off-target sites in primary stem cells, we confirm previous reports on the high prime editor (PE) specificity and its potential for a curative CF gene editing therapy. To facilitate future screening of genetic strategies in a translational CF model, a machine learning algorithm was developed for dynamic quantification of CFTR function in organoids (DETECTOR: "detection of targeted editing of CFTR in organoids").

Considerations for the use of inhaled antibiotics for Pseudomonas aeruginosa in people with cystic fibrosis receiving CFTR modulator therapy

The major cause of mortality in people with cystic fibrosis (pwCF) is progressive lung disease characterised by acute and chronic infections, the accumulation of mucus, airway inflammation, structural damage and pulmonary exacerbations. The prevalence of Pseudomonas aeruginosa rises rapidly in the teenage years, and this organism is the most common cause of chronic lung infection in adults with cystic fibrosis (CF). It is associated with an accelerated decline in lung function and premature death. New P. aeruginosa infections are treated with antibiotics to eradicate the organism, while chronic infections require long-term inhaled antibiotic therapy. The prevalence of P. aeruginosa infections has decreased in CF registries since the introduction of CF transmembrane conductance regulator modulators (CFTRm), but clinical observations suggest that chronic P. aeruginosa infections usually persist in patients receiving CFTRm. This indicates that pwCF may still need inhaled antibiotics in the CFTRm era to maintain long-term control of P. aeruginosa infections. Here, we provide an overview of the changing perceptions of P. aeruginosa infection management, including considerations on detection and treatment, the therapy burden associated with inhaled antibiotics and the potential effects of CFTRm on the lung microbiome. We conclude that updated guidance is required on the diagnosis and management of P. aeruginosa infection. In particular, we highlight a need for prospective studies to evaluate the consequences of stopping inhaled antibiotic therapy in pwCF who have chronic P. aeruginosa infection and are receiving CFTRm. This will help inform new guidelines on the use of antibiotics alongside CFTRm.

mRNA therapies: Pioneering a new era in rare genetic disease treatment

Rare genetic diseases, often referred to as orphan diseases due to their low prevalence and limited treatment options, have long posed significant challenges to our medical system. In recent years, Messenger RNA (mRNA) therapy has emerged as a highly promising treatment approach for various diseases caused by genetic mutations. Chemically modified mRNA is introduced into cells using carriers like lipid-based nanoparticles (LNPs), producing functional proteins that compensate for genetic deficiencies. Given the advantages of precise dosing, biocompatibility, transient expression, and minimal risk of genomic integration, mRNA therapies can safely and effectively correct genetic defects in rare diseases and improve symptoms. Currently, dozens of mRNA drugs targeting rare diseases are undergoing clinical trials. This comprehensive review summarizes the progress of mRNA therapy in treating rare genetic diseases. It introduces the development, molecular design, and delivery systems of mRNA therapy, highlighting their research progress in rare genetic diseases based on protein replacement and gene editing. The review also summarizes research progress in various rare disease models and clinical trials. Additionally, it discusses the challenges and future prospects of mRNA therapy. Researchers are encouraged to join this field and collaborate to advance the clinical translation of mRNA therapy, bringing hope to patients with rare genetic diseases.

Cross-Cutting mHealth Behavior Change Techniques to Support Treatment Adherence and Self-Management of Complex Medical Conditions: Systematic Review

Background

Mobile health (mHealth) interventions have immense potential to support disease self-management for people with complex medical conditions following treatment regimens that involve taking medicine and other self-management activities. However, there is no consensus on what discrete behavior change techniques (BCTs) should be used in an effective adherence and self-management-promoting mHealth solution for any chronic illness. Reviewing the extant literature to identify effective, cross-cutting BCTs in mHealth interventions for adherence and self-management promotion could help accelerate the development, evaluation, and dissemination of behavior change interventions with potential generalizability across complex medical conditions.

Objective

This study aimed to identify cross-cutting, mHealth-based BCTs to incorporate into effective mHealth adherence and self-management interventions for people with complex medical conditions, by systematically reviewing the literature across chronic medical conditions with similar adherence and self-management demands.

Methods

A registered systematic review was conducted to identify published evaluations of mHealth adherence and self-management interventions for chronic medical conditions with complex adherence and self-management demands. The methodological characteristics and BCTs in each study were extracted using a standard data collection form.

Results

A total of 122 studies were reviewed; the majority involved people with type 2 diabetes (28/122, 23%), asthma (27/122, 22%), and type 1 diabetes (19/122, 16%). mHealth interventions rated as having a positive outcome on adherence and self-management used more BCTs (mean 4.95, SD 2.56) than interventions with no impact on outcomes (mean 3.57, SD 1.95) or those that used >1 outcome measure or analytic approach (mean 3.90, SD 1.93; P=.02). The following BCTs were associated with positive outcomes: self-monitoring outcomes of behavior (39/59, 66%), feedback on outcomes of behavior (34/59, 58%), self-monitoring of behavior (34/59, 58%), feedback on behavior (29/59, 49%), credible source (24/59, 41%), and goal setting (behavior; 14/59, 24%). In adult-only samples, prompts and cues were associated with positive outcomes (34/45, 76%). In adolescent and young adult samples, information about health consequences (1/4, 25%), problem-solving (1/4, 25%), and material reward (behavior; 2/4, 50%) were associated with positive outcomes. In interventions explicitly targeting medicine taking, prompts and cues (25/33, 76%) and credible source (13/33, 39%) were associated with positive outcomes. In interventions focused on self-management and other adherence targets, instruction on how to perform the behavior (8/26, 31%), goal setting (behavior; 8/26, 31%), and action planning (5/26, 19%) were associated with positive outcomes.

Conclusions

To support adherence and self-management in people with complex medical conditions, mHealth tools should purposefully incorporate effective and developmentally appropriate BCTs. A cross-cutting approach to BCT selection could accelerate the development of much-needed mHealth interventions for target populations, although mHealth intervention developers should continue to consider the unique needs of the target population when designing these tools.

Developing a nutrition screening tool for children with cystic fibrosis ages 0 to 2 years: Children with cystic fibrosis nutrition screening tool

BACKGROUND

For children with cystic fibrosis (CF), achieving and maintaining optimal growth by the age of 2 years is critical for future health outcomes. A standardized nutrition screening is needed to identify growth problems, enable timely interventions, and improve nutritional outcomes for children (0 to 2 years) with CF. The purpose of this study was to develop a nutrition screening tool for children (0 to 2 years) with CF to identify nutrition risk at every clinical encounter.

METHODS

A retrospective cross-sectional study was used to develop a nutrition screening tool to determine if nutrition interventions needed to change (at-risk) or continue (not at-risk). Retrospective data for pertinent nutrition factors were collected for 99 children attending an accredited CF clinic. The nutrition factors were compared to a dietitian assessment. A stepwise discriminant analysis determined weight-for-age (WFA) and weight-for-length (WFL) z-scores were significant. Then anthropometric data and corresponding dietitian assessment results were collected for children with CF attending two other accredited CF clinics (n = 29, n = 30). Discriminant analysis was used to determine sensitivity and specificity of the nutrition factors and to create a nutrition screening tool equation.

RESULTS

The nutrition screening model that included WFA z-score, LFA z-score, WFL z-score, and weight change velocity adequacy determined nutrition risk the best. The sensitivity was 89.7 %, specificity 83.2 %, NPV 93.3 %, and PPV 75.4 % for this model.

CONCLUSION

The nutrition screening tool equation developed in this study standardizes the process to identify children (0 to 2 years) with CF at nutrition risk. Further validation is needed.

Short-term effects of positive expiratory pressure mask on ventilation inhomogeneity in children with cystic fibrosis: A randomized, sham-controlled crossover study

BACKGROUND

Can physiotherapy with a positive expiratory pressure (PEP) mask improve peripheral ventilation inhomogeneity, a typical feature of children with cystic fibrosis (cwCF)? To answer this question, we used the nitrogen multiple-breath washout (N2MBW) test to measure diffusion-convection-dependent inhomogeneity arising within the intracinar compartment (Sacin*VT).

METHODS

For this randomized, sham-controlled crossover trial, two N2MBW tests were performed near the hospital discharge date: one before and the other after PEP mask therapy (1 min of breathing through a flow-dependent PEP device attached to a face mask, followed by three huffs and one cough repeated 10 times) by either a standard (10-15 cmH20) or a sham (<5 cmH20) procedure on two consecutive mornings. Deception entailed misinforming the subjects about the nature of the study; also the N2MBW operators were blinded to treatment allocation. Study outcomes were assessed with mixed-effect models.

RESULTS

The study sample was 19 cwCF (ten girls), aged 11.4 (2.7) years. The adjusted Sacin*VT mean difference between the standard and the sham procedure was -0.015 (90% confidence interval [CI]: -∞ to 0.025) L-1. There was no statistically significant difference in Scond*VT and lung clearance index between the two procedures: -0.005 (95% CI: -0.019 to 0.01) L-1 and 0.49 (95% CI: -0.05 to 1.03) turnovers, respectively.

CONCLUSION

Our findings do not support evidence for an immediate effect of PEP mask physiotherapy on Sacin*VT with pressure range 10-15 cmH20. Measurement with the N2MBW and the crossover design were found to be time-consuming and unsuitable for a short-term study of airway clearance techniques.

The prevalence of developmental defects of enamel in a cohort of adults with cystic fibrosis - A cross sectional study

OBJECTIVES

Cystic Fibrosis is an autosomal recessive condition. It is a multisystem disease treated with a broad range of pharmacological therapies, diet and nutrition, and physiotherapy. Previous studies suggest that people with cystic fibrosis have a higher prevalence of developmental defects of enamel which may place this population at a greater risk of developing oral diseases such as caries. The aim of this study was to assess a cohort of people with cystic fibrosis (PwCF) for the presence of developmental defects of enamel and compare the results with a control group of people without cystic fibrosis.

METHODS

A cross sectional study involving 92 participants with cystic fibrosis and 92 controls was conducted in Cork University Dental School & Hospital. All participants completed a detailed questionnaire prior to undergoing a full clinical examination. The Developmental Defect of Enamel Index was used as a measurement index. All data was statistically analysed with the help of statisticians from Cystic Fibrosis Registry of Ireland.

RESULTS

64 % (n = 59) of PwCF had enamel defects compared to just 30 % (n = 28) of people without cystic fibrosis. The median number of teeth affected by enamel defects in the study group was 1.5, compared to 0 in the control group.

CONCLUSION

In this study the cohort of PwCF had more enamel defects than people without CF. Further research is required to investigate the aetiology of these findings.

CLINICAL SIGNIFICANCE

Clinicians should be vigilant after teeth have erupted in PwCF as they may have an increased susceptibility to developmental defects of enamel.

Standards for the care of people with cystic fibrosis (CF); Planning for a longer life

This is the final of four papers updating standards for the care of people with CF. That this paper "Planning a longer life" was considered necessary, highlights how much CF care has progressed over the past decade. Several factors underpin this progress, notably increased numbers of people with CF with access to CFTR modulator therapy. As the landscape for CF changes, so do the hopes and aspirations of people with CF and their families. This paper reflects the need to consider people with CF not as a "problem" to be solved, but as a success, a potential and a voice to be heard. People with CF and the wider CF community have driven this approach, reflecting many of the topics in this paper. This exercise involved wide stakeholder engagement. People with CF are keen to contribute to research priorities and be involved in all stages of research. People with CF want healthcare professionals to respect them as individuals and consider the impact of our actions on the world around us. Navigating life presents challenges to all, but for people with CF these challenges are heightened and complex. In this paper we highlight the concerns and life moments that impact people with CF, and events that the CF team should aim to support, including the challenges around having a family. People with CF and their care teams must embrace the updated standards outlined in these four papers to enjoy the full potential for a healthier life.

Effectiveness of lumacaftor/ivacaftor initiation in children with cystic fibrosis aged 2 through 5 years on disease progression: Interim results from an ongoing registry-based study

BACKGROUND

Lumacaftor/ivacaftor (LUM/IVA) has been shown to be safe and efficacious in people with cystic fibrosis (CF) ≥1 year of age. To assess the impact of early LUM/IVA initiation on CF disease progression, a 6-year observational study leveraging data from existing CF patient registries is being conducted in children with CF homozygous for F508del (F/F genotype) who were aged 2 through 5 years at treatment initiation. Here we present interim results from this study focusing on data from the European CF Society Patient Registry (ECFSPR).

METHODS

The LUM/IVA cohort included children in the ECFSPR who started LUM/IVA between 15 January 2019 and 31 December 2020. Longitudinal trends in growth parameters, pulmonary exacerbations, hospitalizations, safety outcomes, and other effectiveness outcomes in the LUM/IVA cohort were compared to those in two modulator-naïve cohorts: (i) matched concurrent cohort heterozygous for F508del and a minimal function mutation (F/MF concurrent comparator cohort) and (ii) matched concurrent cohort with the F/F genotype from countries without commercial access to LUM/IVA as of 2020 (F/F concurrent comparator cohort).

RESULTS

The LUM/IVA cohort matched to the F/MF concurrent comparator cohort had 681 children and the LUM/IVA cohort matched to the F/F concurrent comparator cohort had 183 children. LUM/IVA cohorts had increases in body mass index percentiles relative to the matched F/MF and F/F concurrent comparator cohorts (mean difference in change from baseline: 8.4 [95% CI: 5.5, 11.3] and 11.8 [95% CI: 5.9, 17.7], respectively). Increases in height and weight percentiles were also observed in the LUM/IVA cohort relative to the F/MF and F/F concurrent comparator cohorts. Reductions in pulmonary exacerbations and hospitalizations relative to baseline and the F/F concurrent comparator cohort were seen in 2021.

CONCLUSIONS

This interim analysis showed favorable trends in clinical outcomes, including growth parameters, pulmonary exacerbations, and hospitalizations, suggesting an early beneficial effect of LUM/IVA treatment in children aged 2 through 5 years at treatment initiation.

Combined Liver-Pancreas Transplantation as Novel Treatment for Patient With Cystic Fibrosis: A Case Report

BACKGROUND

A 21-year-old woman diagnosed with cystic fibrosis developed cirrhosis, exocrine pancreatic insufficiency, and insulin-dependent diabetes mellitus. The patient qualified for double organ liver-pancreas transplantation beyond typical indications. The respiratory symptoms of cystic fibrosis were moderate and well-treated. The patient was endangered mainly by liver insufficiency and recurrent hypoglycemia, which was due to the treatment of diabetes with high doses of insulin. Computed tomography showed mild bronchiectasis, cirrhotic liver, splenomegaly, and atrophy of the pancreas. Pseudomonas aeruginosa colonized the upper respiratory tract. Gastrointestinal complications were sufficient for the patient to be qualified for combined liver-pancreas transplantation.

METHODS

First, a standard hepatectomy was performed. The liver was transplanted orthotopically. Subsequently, the team performed pancreas transplantation through a separate incision. The donor's duodenum was anastomosed to the recipient's jejunum, close to the ligament of Treitz.

RESULTS

No serious complications were noted during the postoperative period. Transplanted organs started functioning without delay. The patient was discharged after 6 weeks in general good condition. Twenty months later, the patient felt well, and the grafts kept functioning properly.

CONCLUSION

Combined liver-pancreas transplantation in patients with CF restores exocrine and endocrine pancreatic function and minimizes the risk of life-threatening complications associated with liver insufficiency. Improvement of life quality coincides with the possibility of discontinuing insulin and pancreatic enzyme supplementation. The combination of liver and pancreas transplantation may prevent advanced pulmonary complications, extend the prognosis of survival, and improve the long-term life quality.

Readthrough-induced misincorporated amino acid ratios guide mutant-specific therapeutic approaches for two CFTR nonsense mutations

Cystic fibrosis (CF) is a monogenic disease caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. Premature termination codons (PTCs) represent ∼9% of CF mutations that typically cause severe expression defects of the CFTR anion channel. Despite the prevalence of PTCs as the underlying cause of genetic diseases, understanding the therapeutic susceptibilities of their molecular defects, both at the transcript and protein levels remains partially elucidated. Given that the molecular pathologies depend on the PTC positions in CF, multiple pharmacological interventions are required to suppress the accelerated nonsense-mediated mRNA decay (NMD), to correct the CFTR conformational defect caused by misincorporated amino acids, and to enhance the inefficient stop codon readthrough. The G418-induced readthrough outcome was previously investigated only in reporter models that mimic the impact of the local sequence context on PTC mutations in CFTR. To identify the misincorporated amino acids and their ratios for PTCs in the context of full-length CFTR readthrough, we developed an affinity purification (AP)-tandem mass spectrometry (AP-MS/MS) pipeline. We confirmed the incorporation of Cys, Arg, and Trp residues at the UGA stop codons of G542X, R1162X, and S1196X in CFTR. Notably, we observed that the Cys and Arg incorporation was favored over that of Trp into these CFTR PTCs, suggesting that the transcript sequence beyond the proximity of PTCs and/or other factors can impact the amino acid incorporation and full-length CFTR functional expression. Additionally, establishing the misincorporated amino acid ratios in the readthrough CFTR PTCs aided in maximizing the functional rescue efficiency of PTCs by optimizing CFTR modulator combinations. Collectively, our findings contribute to the understanding of molecular defects underlying various CFTR nonsense mutations and provide a foundation to refine mutation-dependent therapeutic strategies for various CF-causing nonsense mutations.

Attitudes to cross infection, nebuliser hygiene and antimicrobial resistance in people with cystic fibrosis: Results of an international survey

BACKGROUND

Respiratory infection is a major cause of disease severity in people with cystic fibrosis (PwCF). This project aimed to establish the CF community's opinion regarding cross infection (CI), nebuliser hygiene, antimicrobial resistance, personal impact of microbiological findings and the role of the microbiology laboratory.

METHODS

A questionnaire was completed anonymously (n = 280; PwCF (n = 128), parents (n = 123); friends/family/carers/charity personnel (n = 29)) from 13 countries. Readability scores (Flesch Reading Ease (FRE), Flesch Kincaid Grade Level (FKGL)) were determined for CI/IP&C information from six national CF charities and 21 scientific abstracts.

RESULTS

Respondents (72.5%) indicated knowledge of laboratory aspects of CF microbiology was important, however implications of microbiological findings on personal health/well-being were of higher importance (p < 0.0001). Cross infection/infection prevention & control (CI/IP&C) was of highest importance (95.6% respondents) with 27.3% indicating they were not given adequate information, particularly in older respondents (50 y+) (p = 0.006) versus young adults (16-29 y) and respondents from the Middle East versus N. America (p = 0.022) and Europe (p = 0.045). Responses highlighted how CI/IP&C health literacy could be enhanced. Respondents (77.3%), particularly females (p < 0.0001), indicated they would increase the frequency of nebuliser disinfection following guidance on infection risks/best practice, therefore an educational video was prepared. CI/IP&C readability scores (mean ± sd) from CF charities (FRE 52.5 ± 10.8; FKGL 9.7 ± 2.3) were more readable (p < 0.0001) than scientific abstracts (FRE 13.3 ± 11.1; FKGL 16.9 ± 2.3), however not meeting the targets (FRE≥60 and FKGL≤8).

CONCLUSION

There is a requirement for further CI/IP&C evidence-based guidance, policies/guidelines, education awareness, best practice in the home environment and multi-modal communication, enabling the CF community to make informed choices on lifestyle behaviours.

Porcine-derived pancreatic enzyme replacement therapy may be linked to chronic hepatitis E virus infection in cystic fibrosis lung transplant recipients

OBJECTIVES

In high-income countries hepatitis E virus (HEV) is an uncommonly diagnosed porcine-derived zoonoses. After identifying disproportionate chronic HEV infections in persons with cystic fibrosis (pwCF) postlung transplant, we sought to understand its epidemiology and potential drivers.

DESIGN

All pwCF post-transplant attending our regional CF centre were screened for HEV. HEV prevalence was compared against non-transplanted pwCF and with all persons screened for suspected HEV infection from 2016 to 2022 in Alberta, Canada. Those with chronic HEV infection underwent genomic sequencing and phylogenetic analysis. Owing to their swine derivation, independently sourced pancreatic enzyme replacement therapy (PERT) capsules were screened for HEV.

RESULTS

HEV seropositivity was similar between transplanted and non-transplanted pwCF (6/29 (21%) vs 16/83 (19%); p=0.89). Relative to all other Albertans investigated for HEV as a cause of hepatitis (n=115/1079, 10.7%), pwCF had a twofold higher seropositivity relative risk and this was four times higher than the Canadian average. Only three chronic HEV infection cases were identified in all of Alberta, all in CF lung transplant recipients (n=3/29, 10.3%). Phylogenetics confirmed cases were unrelated porcine-derived HEV genotype 3a. Ninety-one per cent of pwCF were taking PERT (median 8760 capsules/person/year). HEV RNA was detected by RT-qPCR in 44% (47/107) of PERT capsules, and sequences clustered with chronic HEV cases.

CONCLUSION

PwCF had disproportionate rates of HEV seropositivity, regardless of transplant status. Chronic HEV infection was evident only in CF transplant recipients. HEV may represent a significant risk for pwCF, particularly post-transplant. Studies to assess HEV incidence and prevalence in pwCF, and potential role of PERT are required.

Discovery of GLPG2737, a Potent Type 2 Corrector of CFTR for the Treatment of Cystic Fibrosis in Combination with a Potentiator and a Type 1 Co-corrector

Cystic fibrosis (CF) is caused by mutations in the CF transmembrane conductance regulator (CFTR) protein. This epithelial anion channel regulates the active transport of chloride and bicarbonate ions across membranes. Mutations result in reduced surface expression of CFTR channels with impaired functionality. Correctors are small molecules that support the trafficking of CFTR to increase its membrane expression. Such correctors can have different mechanisms of action. Combinations may result in a further improved therapeutic benefit. We describe the identification and optimization of a new pyrazolol3,4-bl pyridine-6-carboxylic acid series with high potency and efficacy in rescuing CFTR from the cell surface. Investigations showed that carboxylic acid group replacement with acylsulfonamides and acylsulfonylureas improved ADMET and PK properties, leading to the discovery of the structurally novel co-corrector GLPG2737. The addition of GLPG2737 to the combination of the potentiator GLPG1837 and C1 corrector 4 led to an 8-fold increase in the F508del CFTR activity.

Prominent role of gut dysbiosis in the pathogenesis of cystic fibrosis-related liver disease in mice

BACKGROUND & AIMS

Cystic fibrosis-related liver disease (CFLD) is a chronic cholangiopathy that increases morbidity and mortality in patients with CF. Current treatments are unsatisfactory, and incomplete understanding of CFLD pathogenesis hampers therapeutic development. We have previously shown that mouse CF cholangiocytes respond to lipopolysaccharide with excessive inflammation. Thus, we investigated the role of the gut-liver axis in the pathogenesis of CFLD.

METHODS

Wild-type (WT), whole-body Cftr knockout (CFTR-KO) and gut-corrected (CFTR-KO-GC) mice were studied. Liver changes were assessed by immunohistochemistry and single-cell transcriptomics (single-cell RNA sequencing), inflammatory mediators were analysed by proteome array, faecal microbiota by 16S ribosomal RNA sequencing and gut permeability by FITC-dextran assay.

RESULTS

The livers of CFTR-KO mice showed ductular proliferation and periportal inflammation, whereas livers of CFTR-KO-GC mice had no evident pathology. Single-cell RNA sequencing analysis of periportal cells showed increased presence of neutrophils, macrophages and T cells, and activation of pro-inflammatory and pathogen-mediated immune pathways in CFTR-KO livers, consistent with a response to gut-derived stimuli. CFTR-KO mice exhibited gut dysbiosis with enrichment of Enterobacteriaceae and Enterococcus spp., which was associated with increased intestinal permeability and mucosal inflammation, whereas gut dysbiosis and inflammation were absent in CFTR-KO-GC mice. Treatment with nonabsorbable antibiotics ameliorated intestinal permeability and liver inflammation in CFTR-KO mice. Faecal microbiota transfer from CFTR-KO to germ-free WT mice did not result in dysbiosis nor liver pathology, indicating that defective intestinal CFTR is required to maintain dysbiosis.

CONCLUSION

Defective CFTR in the gut sustains a pathogenic microbiota, creates an inflammatory milieu, and alters intestinal permeability. These changes are necessary for the development of cholangiopathy. Restoring CFTR in the intestine or modulating the microbiota could be a promising strategy to prevent or attenuate liver disease.

IMPACT AND IMPLICATIONS

Severe cystic fibrosis-related liver disease (CFLD) affects 10% of patients with cystic fibrosis (CF) and contributes to increased morbidity and mortality. Treatment options remain limited due to a lack of understanding of disease pathophysiology. The cystic fibrosis transmembrane conductance regulator (CFTR) mediates Cl- and HCO3- secretion in the biliary epithelium and its defective function is thought to cause cholestasis and excessive inflammatory responses in CF. However, our study in Cftr-knockout mice demonstrates that microbial dysbiosis, combined with increased intestinal permeability caused by defective CFTR in the intestinal mucosa, acts as a necessary co-factor for the development of CFLD-like liver pathology in mice. These findings uncover a major role for the gut microbiota in CFLD pathogenesis and call for further investigation and clinical validation to develop targeted therapeutic strategies acting on the gut-liver axis in CF.

Diversity of CFTR variants across ancestries characterized using 454,727 UK biobank whole exome sequences

BACKGROUND

Limited understanding of the diversity of variants in the cystic fibrosis transmembrane conductance regulator (CFTR) gene across ancestries hampers efforts to advance molecular diagnosis of cystic fibrosis (CF). The consequences pose a risk of delayed diagnoses and subsequently worsened health outcomes for patients. Therefore, characterizing the spectrum of CFTR variants across ancestries is critical for revolutionizing molecular diagnoses of CF.

METHODS

We analyzed 454,727 UK Biobank (UKBB) whole-exome sequences to characterize the diversity of CFTR variants across ancestries. Using the PanUKBB classification, the participants were assigned into six major groups: African (AFR), American/American Admixed (AMR), Central South Asia (CSA), East Asian (EAS), European (EUR), and Middle East (MID). We segregated ancestry-specific CFTR variants, including those that are CF-causing or clinically relevant. The ages of certain CF-causing variants were determined and analyzed for selective pressure effects, and curated phenotype analysis was performed for participants with clinically relevant CFTR genotypes.

RESULTS

We detected over 4000 CFTR variants, including novel ancestry-specific variants, across six ancestries. Europeans had the most unique CFTR variants [n = 2212], while the American group had the least unique variants [n = 23]. F508del was the most prevalent CF-causing variant found in all ancestries, except in EAS, where V520F was the most prevalent. Common EAS variants such as 3600G > A, V456A, and V520, which appeared approximately 270, 215, and 338 generations ago, respectively, did not show evidence of selective pressure. Sixteen participants had two CF-causing variants, with two being diagnosed with CF. We found 154 participants harboring a CF-causing and varying clinical consequences (VCC) variant. Phenotype analysis performed for participants with multiple clinically relevant variants returned significant associations with CF and its pulmonary phenotypes [Bonferroni-adjusted p < 0.05].

CONCLUSIONS

We leveraged the UKBB database to comprehensively characterize the broad spectrum of CFTR variants across ancestries. The detection of over 4000 CFTR variants, including several ancestry-specific and uncharacterized CFTR variants, warrants the need for further characterization of their functional and clinical relevance. Overall, the presentation of classical CF phenotypes seen in non-CF diagnosed participants with more than one CF-causing variant indicates that they may benefit from current CFTR modulator therapies.

Microbiology of cystic fibrosis persons not chronically infected with P. aeruginosa: A quasi-experimental study on two different upper airways' sampling methods

Background

The upper airways of cystic fibrosis (CF) persons are an evolutionary niche where genetically adapted bacterial strains are selected for lung infection. The microbiological studies conducted up to now on the upper airways are not easily comparable.

Methods

Using classical culture methods, we simultaneously studied the microbiological status of upper and lower airways in persons not chronically infected with P. aeruginosa. Each person had a single upper airways sampling and a concomitant lower airways sampling. Lower airways sampling was performed by oropharyngeal swab or sputum collection. Using a quasi-experimental design of study, we evaluated the performance of 2 different upper airways' sampling methods, nasal lavage according to method described by Mainz or nasal lavage with a rhino-set. Pain was measured with appropriate scales.

Results

A total of 194 persons were enrolled in this study. Pathogenic flora was found in 128 (6.6%) of 194 upper airways samples and in 164 (84.6%) lower airways samples. A statistically significant difference between the upper airways and the lower airways was found in the isolation of S. aureus and non-fermenter gram negatives. Nasal lavage according to Mainz resulted in the isolation of more non-fermenter gramnegatives than the rhino-set (p < 0.05). No differences were found in the pain caused bythe two methods.

Conclusions

In our study population, cultures of the upper airway and lower airway differ in CF persons. In people sampled with nasal lavage according to Mainz more non-fermenter gram negatives were detected than with rhino-set. The two sampling methods were comparable with regard to the caused pain, nasal lavage according to Mainz method being quicker to perform.

PTI-801 (posenacaftor) shares a common mechanism with VX-445 (elexacaftor) to rescue p.Phe508del-CFTR

The deletion of a phenylalanine at position 508 (p.Phe508del) in the CFTR anion channel is the most prevalent variant in people with Cystic Fibrosis (CF). This variant impairs folding and stability of the CF transmembrane conductance regulator (CFTR) protein, resulting in its defective trafficking and premature degradation. Over the last years, therapeutic accomplishments have been attained in developing small molecules that partially correct p.Phe508del-CFTR defects; however, the mechanism of action (MoA) of these compounds has only started to be uncovered. In this study, we employed biochemical, fluorescence microscopy, and functional assays to examine the efficacy and properties of PTI-801, a newly developed p.Phe508del-CFTR corrector. To exploit its MoA, we assessed PTI-801 effects in combination with low temperature, genetic revertants of p.Phe508del-CFTR (the in cis p.Val510Asp, p.Gly550Glu, p.Arg1070Trp, and 4RK) and other correctors. Our results demonstrated that PTI-801 rescues p.Phe508del-CFTR processing, PM trafficking, and channel function (upon agonist stimulation) with greater correction effects in combination with ABBV-2222, FDL-169, VX-661, or VX-809, but not with VX-445. Although PTI-801 exhibited no potentiator activity on low temperature- and corrector-rescued p.Phe508del-CFTR, this compound displayed similar behavior to that of VX-445 on genetic revertants. Such evidence associated with the lack of additivity when PTI-801 and VX-445 were combined indicates that they share a common binding site to correct p.Phe508del-CFTR defects. Despite the high efficacy of PTI-801 in combination with ABBV-2222, FDL-169, VX-661, or VX-809, these dual corrector combinations only partially restored p.Phe508del-CFTR conformational stability, as shown by the lower half-life of the mutant protein compared to that of WT-CFTR. In summary, PTI-801 likely shares a common MoA with VX-445 in rescuing p.Phe508del-CFTR, thus being a feasible alternative for the development of novel corrector combinations with greater capacity to rescue mutant CFTR folding and stability.

OrgaSegment: deep-learning based organoid segmentation to quantify CFTR dependent fluid secretion

Epithelial ion and fluid transport studies in patient-derived organoids (PDOs) are increasingly being used for preclinical studies, drug development and precision medicine applications. Epithelial fluid transport properties in PDOs can be measured through visual changes in organoid (lumen) size. Such organoid phenotypes have been highly instrumental for the studying of diseases, including cystic fibrosis (CF), which is characterized by genetic mutations of the CF transmembrane conductance regulator (CFTR) ion channel. Here we present OrgaSegment, a MASK-RCNN based deep-learning segmentation model allowing for the segmentation of individual intestinal PDO structures from bright-field images. OrgaSegment recognizes spherical structures in addition to the oddly-shaped organoids that are a hallmark of CF organoids and can be used in organoid swelling assays, including the new drug-induced swelling assay that we show here. OrgaSegment enabled easy quantification of organoid swelling and could discriminate between organoids with different CFTR mutations, as well as measure responses to CFTR modulating drugs. The easy-to-apply label-free segmentation tool can help to study CFTR-based fluid secretion and possibly other epithelial ion transport mechanisms in organoids.

Cell type-specific regulation of CFTR trafficking-on the verge of progress

Trafficking of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) protein is a complex process that starts with its biosynthesis and folding in the endoplasmic reticulum. Exit from the endoplasmic reticulum (ER) is coupled with the acquisition of a compact structure that can be processed and traffic through the secretory pathway. Once reaching its final destination-the plasma membrane, CFTR stability is regulated through interaction with multiple protein partners that are involved in its post-translation modification, connecting the channel to several signaling pathways. The complexity of the process is further boosted when analyzed in the context of the airway epithelium. Recent advances have characterized in detail the different cell types that compose the surface epithelium and shifted the paradigm on which cells express CFTR and on their individual and combined contribution to the total expression (and function) of this chloride/bicarbonate channel. Here we review CFTR trafficking and its relationship with the knowledge on the different cell types of the airway epithelia. We explore the crosstalk between these two areas and discuss what is still to be clarified and how this can be used to develop more targeted therapies for CF.

Cardiopulmonary Exercise Testing Provides Prognostic Information in Advanced Cystic Fibrosis Lung Disease

Rationale: Cardiopulmonary exercise testing (CPET) provides prognostic information in cystic fibrosis (CF); however, its prognostic value for patients with advanced CF lung disease is unknown. Objectives: To determine the prognostic value of CPET on the risk of death or lung transplant (LTX) within 2 years. Methods: We retrospectively collected data from 20 CF centers in Asia, Australia, Europe, and North America on patients with a forced expiratory volume in 1 second (FEV1) ⩽ 40% predicted who performed a cycle ergometer CPET between January 2008 and December 2017. Time to death/LTX was analyzed using mixed Cox proportional hazards regression. Conditional inference trees were modeled to identify subgroups with increased risk of death/LTX. Results: In total, 174 patients (FEV1, 30.9% ± 5.8% predicted) were included. Forty-four patients (25.5%) died or underwent LTX. Cox regression analysis adjusted for age, sex, and FEV1 revealed percentage predicted peak oxygen uptake ([Formula: see text]o2peak) and peak work rate (Wpeak) as significant predictors of death/LTX: adjusted hazard ratios per each additional 10% predicted were 0.60 (95% confidence interval, 0.43-0.90; P = 0.008) and 0.60 (0.48-0.82; P < 0.001). Tree-structured regression models, including a set of 11 prognostic factors for survival, identified Wpeak to be most strongly associated with 2-year risk of death/LTX. Probability of death/LTX was 45.2% for those with a Wpeak ⩽ 49.2% predicted versus 10.9% for those with a Wpeak > 49.2% predicted (P < 0.001). Conclusions: CPET provides prognostic information in advanced CF lung disease, and Wpeak appears to be a promising marker for LTX referral and candidate selection.

Global disparities in cystic fibrosis outcomes prior to CFTR modulators: A CF registries cohort study in South Africa and Canada

BACKGROUND

Outcomes of cystic fibrosis (CF) differ between low-middle income and high-income countries, but comparative data are lacking. We compared South African (SA) and Canadian CF outcomes to explore what disparities existed prior to access of CFTR modulators in Canada.

METHODS

A cross-sectional study of SA and Canadian CF registries data for period 1 January to 31 December 2018. CF registry data were harmonised between countries to compare lung function and nutrition outcomes. Poor nutrition was defined as BMIz-score < -1 in children and < 18.5 kg/m2 in adults. Standardised mean difference (SMD) >10 was considered significant.

RESULTS

After excluding Canadians on CFTR modulators and lung transplant recipients, data on 4049 Canadian and 446 SA people was analysed. Compared to Canada, people in SA were younger (median age 15.8 years vs. 24.1 years: SMD 52) with fewer males (47.8% vs 54.2%; SMD 12.5) and White (70.9% vs. 93.3%; SMD 61.3). Class I-III CFTR mutation frequency was similar in SA (n = 384, 86.1%) and Canada (n = 3426, 84.9%). After adjusting for age, gender, diagnosis age, genotype, P.aeruginosa infection and pulmonary treatments, FEV1pp was 8.9% lower (95% CI 6.3% to 11.4%) and poor nutrition 1.7-fold more common (OR 1.70; 95% CI 1.19-2.41) in SA compared to Canada.

CONCLUSION

Lung function and nutrition was significantly lower in SA compared to Canada. Global disparities in CF outcomes between high and low-middle income countries are likely to widen as CFTR modulators are rapidly scaled up in only high-income countries.

Fecal dysbiosis and inflammation in intestinal-specific Cftr knockout mice on regimens preventing intestinal obstruction

Chronic intestinal inflammation is a poorly understood manifestation of cystic fibrosis (CF), which may be refractory to ion channel CF transmembrane conductance regulator (CFTR) modulator therapy. People with CF exhibit intestinal dysbiosis, which has the potential for stimulating intestinal and systemic inflammation. CFTR is expressed in organ epithelia, leukocytes, and other tissues. Here, we investigate the contribution of intestinal epithelium-specific loss of Cftr [iCftr knockout (KO)] to dysbiosis and inflammation in mice treated with either of two antiobstructive dietary regimens necessary to maintain CF mouse models [polyethylene glycol (PEG) laxative or a liquid diet (LiqD)]. Feces collected from iCftr KO mice and their wild-type (WT) sex-matched littermates were used to measure fecal calprotectin to evaluate inflammation and to perform 16S rRNA sequencing to characterize the gut microbiome. Fecal calprotectin was elevated in iCftr KO relative to WT mice that consumed either PEG or LiqD. PEG iCftr KO mice did not show a change in α diversity versus WT mice but demonstrated a significant difference in microbial composition (β diversity) with included increases in the phylum Proteobacteria, the family Peptostreptococcaceae, four genera of Clostridia including C. innocuum, and the mucolytic genus Akkermansia. Fecal microbiome analysis of LiqD-fed iCftr KO mice showed both decreased α diversity and differences in microbial composition with increases in the Proteobacteria family Enterobacteriaceae, Firmicutes families Clostridiaceae and Peptostreptococcaceae, and enrichment of Clostridium perfringens, C. innocuum, C. difficile, mucolytic Ruminococcus gnavus, and reduction of Akkermansia. It was concluded that epithelium-specific loss of Cftr is a major driver of CF intestinal dysbiosis and inflammation with significant similarities to previous studies of pan Cftr KO mice.NEW & NOTEWORTHY Chronic intestinal inflammation is a manifestation of cystic fibrosis (CF), a disease caused by loss of the anion channel CF transmembrane conductance regulator (CFTR) that is expressed in many tissues. This study shows that intestinal epithelial cell-specific loss of CFTR [inducible Cftr knockout (KO)] in mice is sufficient to induce intestinal dysbiosis and inflammation. Experiments were performed on mice consuming two dietary regimens routinely used to prevent obstruction in CF mice.

Electronic home monitoring of children with cystic fibrosis to detect and treat acute pulmonary exacerbations and its effect on 1-year FEV1

BACKGROUND

We aimed to investigate the effect of the use of electronic home spirometry in children with cystic fibrosis (CF) on 1-year FEV1 (% predicted, pp) change.

METHODS

This is a randomised, one-year prospective study including children with CF between 6 and 18 years of age. Subjects were randomised into home spirometry group (HSG) and usual care group (UCG). Children in HSG performed two pulmonary function tests (PFT) per week. Data regarding acute pulmonary exacerbations (PEx) was obtained from patients' records. At baseline and 12th month, health related quality of life questionnaire for CF patients (CFQ-R) and lung clearance index (LCI) were performed.

RESULTS

Sixty children were recruited with a median (IQR) age of 13.3 (11.4-15.4) years. Absolute change in FEV1pp from baseline to 12th month as median (IQR) was +1% (-6.75-9.75) in HSG and -2.50% (-7.50-3.25) in UCG (p = 0.10). Sensitivity analysis including only adherent children in HSG (n = 22), yielded an increase of 5% (-3.50-12) in HSG and a decrease of 2.50% (-7.50-3.25) in UCG (p = 0.009). A total of 29 (96.7%) subjects in HSG and 23 (76.7%) in UCG had PEx (p = 0.05). Absolute change in median (IQR) LCI2.5 from baseline to the 12th month was -1.6 [-2.9-0] (p<0.001) in HSG and -1.5 [-2.8-(-0.6)] (p<0.001) in UCG (p = 0.94). There was a significant increase in the social domain of the CFQ-R in HSG (from 59.1 to 76.2, p = 0.01).

CONCLUSIONS

Electronic home monitoring of children with CF by spirometry may result in improvement in lung function.

Unmet challenges in cystic fibrosis treatment with modulators

INTRODUCTION

'Highly effective' modulator therapies (HEMTs) have radically changed the Cystic Fibrosis (CF) therapeutic landscape.

AREAS COVERED

A comprehensive search strategy was undertaken to assess impact of HEMT in life of pwCF, treatment challenges in specific populations such as very young children, and current knowledge gaps.

EXPERT OPINION

HEMTs are prescribed for pwCF with definite genotypes. The heterogeneity of variants complicates treatment possibilities and around 10% of pwCF worldwide remains ineligible. Genotype-specific treatments are prompting theratyping and personalized medicine strategies. Improvement in lung function and quality of life increase survival rates, shifting CF from a pediatric to an adult disease. This implies new studies addressing long-term efficacy, side effects, emergence of adult co-morbidities and possible drug-drug interactions. More sensitive and predictive biomarkers for both efficacy and toxicity are warranted. As HEMTs cross the placenta and are found in breast milk, studies addressing the potential consequences of treatment during pregnancy and breastfeeding are urgently needed. Finally, although the treatment and expected outcomes of CF have improved dramatically in high- and middle-income countries, lack of access in low-income countries to these life-changing medicines highlights inequity of care worldwide.

Cystic fibrosis in Europe: improved lung function and longevity - reasons for cautious optimism, but challenges remain

BACKGROUND

Prognosis and disease severity in cystic fibrosis (CF) are linked to declining lung function. To characterise lung function by the number of adults in countries with different levels of Gross National Income (GNI), data from the European Cystic Fibrosis Society Patient Registry were utilised.

METHODS

Annual data including age, forced expiratory volume in 1 s (FEV1), anthropometry, genotype, respiratory cultures and CF-related diabetes (CFRD) were retrieved between 2011 and 2021. All countries were stratified into GNI per capita to reflect differences within Europe.

RESULTS

A consistent improvement in FEV1 % pred and survival was observed among the 47 621 people with CF (pwCF), including subjects with chronic Pseudomonas aeruginosa infection, CFRD and/or undernutrition. Mean values of FEV1 % pred changed from 85% to 94.2% for children and from 63.6% to 74.7% for adults. FEV1 % pred further increased among those carrying the F508del mutation in 2021, when elexacaftor/tezacaftor/ivacaftor was available. The number of adult pwCF increased from 13 312 in 2011 to 21 168 in 2021, showing a 60% increase. PwCF living in European lower income countries did not demonstrate a significant annual increase in FEV1 % pred or in the number of adults.

CONCLUSION

This pan-European analysis demonstrates a consistent improvement in FEV1 % pred, number of adult pwCF and survival over the last decade only in European higher and middle income countries. Urgent action is needed in the lower income countries where such improvement was not observed. The notable improvement observed in pwCF carrying the F508del mutation emphasises the need to develop treatments for all CF mutations.

In vitro modulator responsiveness of 655 CFTR variants found in people with cystic fibrosis

BACKGROUND

In 2017, the US Food and Drug Administration initiated expansion of drug labels for the treatment of cystic fibrosis (CF) to include CF transmembrane conductance regulator (CFTR) gene variants based on in vitro functional studies. This study aims to identify CFTR variants that result in increased chloride (Cl-) transport function by the CFTR protein after treatment with the CFTR modulator combination elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA). These data may benefit people with CF (pwCF) who are not currently eligible for modulator therapies.

METHODS

Plasmid DNA encoding 655 CFTR variants and wild-type (WT) CFTR were transfected into Fisher Rat Thyroid cells that do not natively express CFTR. After 24 h of incubation with control or TEZ and ELX, and acute addition of IVA, CFTR function was assessed using the transepithelial current clamp conductance assay. Each variant's forskolin/cAMP-induced baseline Cl- transport activity, responsiveness to IVA alone, and responsiveness to the TEZ/ELX/IVA combination were measured in three different laboratories. Western blots were conducted to evaluate CFTR protein maturation and complement the functional data.

RESULTS AND CONCLUSIONS

253 variants not currently approved for CFTR modulator therapy showed low baseline activity (<10 % of normal CFTR Cl- transport activity). For 152 of these variants, treatment with ELX/TEZ/IVA improved the Cl- transport activity by ≥10 % of normal CFTR function, which is suggestive of clinical benefit. ELX/TEZ/IVA increased CFTR function by ≥10 percentage points for an additional 140 unapproved variants with ≥10 % but <50 % of normal CFTR function at baseline. These findings significantly expand the number of rare CFTR variants for which ELX/TEZ/IVA treatment should result in clinical benefit.

A Polyclonal Antibody against a Burkholderia cenocepacia OmpA-like Protein Strongly Impairs Pseudomonas aeruginosa and B. multivorans Virulence

Despite advances in therapies, bacterial chronic respiratory infections persist as life-threatening to patients suffering from cystic fibrosis (CF). Pseudomonas aeruginosa and bacteria of the Burkholderia cepacia complex are among the most difficult of these infections to treat, due to factors like their resistance to multiple antibiotics and ability to form biofilms. The lack of effective antimicrobial strategies prompted our search for alternative immunotherapies that can effectively control and reduce those infections among CF patients. Previous work from our group showed that the anti-BCAL2645 goat polyclonal antibody strongly inhibited Burkholderia cenocepacia to adhere and invade cultured epithelial cells. In this work, we showed that the polyclonal antibody anti-BCAL2645 also strongly inhibited the ability of P. aeruginosa to form biofilms, and to adhere and invade the human bronchial epithelial cell line CFBE41o-. The polyclonal antibody also inhibited, to a lesser extent, the ability of B. multivorans to adhere and invade the human bronchial epithelial cell line CFBE41o. We also show that the ability of B. cenocepacia, P. aeruginosa and B. multivorans to kill larvae of the Galleria mellonella model of infection was impaired when bacteria were incubated with the anti-BCAL2645 antibody prior to the infection. Our findings show that an antibody against BCAL2645 possesses a significant potential for the development of new immunotherapies against these three important bacterial species capable of causing devastating and often lethal infections among CF patients.

Paediatric Thoracic Imaging in Cystic Fibrosis in the Era of Cystic Fibrosis Transmembrane Conductance Regulator Modulation

Cystic fibrosis (CF) is one of the most common progressive life-shortening genetic conditions worldwide. Ground-breaking translational research has generated therapies that target the primary cystic fibrosis transmembrane conductance regulator (CFTR) defect, known as CFTR modulators. A crucial aspect of paediatric CF disease is the development and progression of irreversible respiratory disease in the absence of clinical symptoms. Accurate thoracic diagnostics have an important role to play in this regard. Chest radiographs are non-specific and insensitive in the context of subtle changes in early CF disease, with computed tomography (CT) providing increased sensitivity. Recent advancements in imaging hardware and software have allowed thoracic CTs to be acquired in paediatric patients at radiation doses approaching that of a chest radiograph. CFTR modulators slow the progression of CF, reduce the frequency of exacerbations and extend life expectancy. In conjunction with advances in CT imaging techniques, low-dose thorax CT will establish a central position in the routine care of children with CF. International guidelines regarding the choice of modality and timing of thoracic imaging in children with CF are lagging behind these rapid technological advances. The continued progress of personalised medicine in the form of CFTR modulators will promote the emergence of personalised radiological diagnostics.

Optimizing sexual reproductive health of men and women with cystic fibrosis: A systematic review

This systematic review summarizes the impact of cystic fibrosis (CF) on sexual and reproductive health (SRH) in males and females, covering pubertal development, hormonal function, family planning, and fertility. Included articles featured historical CF diagnostic criteria, preclinical or clinical data (retrospective cohorts or open label trials), while excluded articles lacked full text availability, explicit methodology, or comparisons between CF and non-CF patients. Genotype differences in CFTR mutations influenced symptom severity. Males with CF experienced delayed puberty, hypogonadism, infertility from obstructive azoospermia, and semen parameter issues. Female CF patients showed decreased fertility, possibly linked to disrupted ionic balance and ovarian cystic disease. Assistive reproductive technologies addressed fertility issues, but success varied based on disease severity and genotype. CFTR modulators aided pulmonary function and sexual health but require further assessment for fertility benefits.

Safety and Pharmacokinetics Following Oral or Intravenous Lefamulin in Adults With Cystic Fibrosis

PURPOSE

Methicillin-resistant Staphylococcus aureus infections are increasing in prevalence in patients with cystic fibrosis (CF) and are associated with worsening lung function and increased mortality. Lefamulin is a pleuromutilin antimicrobial approved to treat community-acquired bacterial pneumonia based on potent in vitro activity and clinical efficacy. This Phase I, open-label, randomized crossover study assessed the safety and pharmacokinetic profile of oral and intravenous (IV) lefamulin in adults with CF.

METHODS

The study comprised 2 dosing periods in which adults with CF (N = 13) received a single dose of lefamulin via a 150-mg IV infusion or 600-mg immediate-release orally administered tablet, separated by a 4- to 7-day washout period. Pharmacokinetic and safety parameters were assessed after lefamulin treatment.

FINDINGS

Single doses of lefamulin administered via oral tablet or IV infusion resulted in comparable drug exposure, and sputum analysis suggested rapid penetration of lefamulin into the lung. Comparison of the present results with those obtained from prior single-dose studies of healthy volunteers indicate no meaningful difference in the pharmacokinetic properties of lefamulin in patients with CF. Treatment-emergent adverse events were consistent with previous reports, and the majority were mild in severity.

IMPLICATIONS

These results show similar lefamulin pharmacokinetic and safety profiles between patients with CF and healthy volunteers receiving the same oral and IV doses, suggesting no need for lefamulin dose adjustment in patients with CF and indicating the potential of lefamulin as therapy for lung infections in patients with CF.

CLINICALTRIALS

gov identifier: NCT05225805.

Nanoparticle-based platforms for targeted drug delivery to the pulmonary system as therapeutics to curb cystic fibrosis: A review

Cystic fibrosis (CF) is a genetic disorder of the respiratory system caused by mutation of the Cystic Fibrosis Trans-Membrane Conductance Regulator (CFTR) gene that affects a huge number of people worldwide. It results in difficulty breathing due to a large accumulation of mucus in the respiratory tract, resulting in serious bacterial infections, and subsequent death. Traditional drug-based treatments face hindered penetration at the site of action due to the thick mucus layer. Nanotechnology offers possibilities for developing advanced and effective treatment platforms by focusing on drugs that can penetrate the dense mucus layer, fighting against the underlying bacterial infections, and targeting the genetic cause of the disease. In this review, current nanoparticle-mediated drug delivery platforms for CF, challenges in therapeutics, and future prospects have been highlighted. The effectiveness of the different types of nano-based systems conjugated with various drugs to combat the symptoms and the challenges of treating CF are brought into focus. The toxic effects of these nano-medicines and the various factors that are responsible for their effectiveness are also highlighted.

Positioning the preventive potential of microbiome treatments for cystic fibrosis in the context of current therapies

Antibiotics and cystic fibrosis transmembrane conductance regulator (CFTR) modulators play a pivotal role in cystic fibrosis (CF) treatment, but both have limitations. Antibiotics are linked to antibiotic resistance and disruption of the airway microbiome, while CFTR modulators are not widely accessible, and structural lung damage and pathogen overgrowth still occur. Complementary strategies that can beneficially modulate the airway microbiome in a preventive way are highly needed. This could be mediated via oral probiotics, which have shown some improvement of lung function and reduction of airway infections and exacerbations, as a cost-effective approach. However, recent data suggest that specific and locally administered probiotics in the respiratory tract might be a more targeted approach to prevent pathogen outgrowth in the lower airways. This review aims to summarize the current knowledge on the CF airway microbiome and possibilities of microbiome treatments to prevent bacterial and/or viral infections and position them in the context of current CF therapies.