Cystic fibrosis patients of minority race and ethnicity less likely eligible for CFTR modulators based on CFTR genotype

Advances in Care and Outcomes for Children with Cystic Fibrosis

The landscape of care for children with cystic fibrosis (CF), a genetic disorder of chloride transport with multisystem manifestations including inspissated mucus, recurrent sinopulmonary infections, obstructive lung disease, and exocrine pancreatic insufficiency, is rapidly changing. Early diagnosis via newborn screening enabling timely nutritional support, chronic therapies to improve mucociliary clearance, and prompt treatment of pulmonary infections have improved overall outcomes in children with CF. More widespread availability of novel cystic fibrosis transmembrane conductance regulator modulator therapies for children continues to revolutionize pediatric CF care.However, significant challenges exist to optimize care and outcomes for all children with CF.

The expanded French compassionate programme for elexacaftor-tezacaftor-ivacaftor use in people with cystic fibrosis without a F508del CFTR variant: a real-world study

BACKGROUND

Elexacaftor-tezacaftor-ivacaftor has been approved in Europe for people with cystic fibrosis with at least one F508del CFTR variant. Additionally, it is approved by the US Food and Drug Administration (FDA) for people with cystic fibrosis with at least one of 177 rare variants. The aims of this study were to describe the clinical response to elexacaftor-tezacaftor-ivacaftor for people with cystic fibrosis without a F508del CFTR variant in France and to determine CFTR variant responsiveness to elexacaftor-tezacaftor-ivacaftor based on the observed clinical response.

METHODS

The French compassionate programme expanded access to elexacaftor-tezacaftor-ivacaftor to people with cystic fibrosis, aged 6 years and older, without a F508del variant, excluding those with two variants previously characterised as non-responsive. Participants at France's 47 cystic fibrosis centres were given a 4-6 week trial of elexacaftor-tezacaftor-ivacaftor and response was determined by a centralised committee based on evolution of clinical data, lung function, and sweat chloride concentration. Responsiveness of individual CFTR variants was derived from observed clinical responses.

FINDINGS

The first compassionnate programme was launched on May 19, 2022; by March 8, 2024, 516 people with cystic fibrosis had been identified for inclusion in this real-word study: 37 were not included due to the presence of two variants previously characterised as non-responsive to elexacaftor-tezacaftor-ivacaftor, and 479 (229 females [48%] and 250 males [52%]) received elexacaftor-tezacaftor-ivacaftor for 4-6 weeks. Among 443 participants who received no CFTR modulator before elexacaftor-tezacaftor-ivacaftor, 83 had at least one FDA-approved variant, of whom 81 (98%) were responders and continued elexacaftor-tezacaftor-ivacaftor; in responders, mean absolute change in sweat chloride was -44·5 mmol/L (95% CI -39·1 to -49·8) and percentage of predicted FEV1 (ppFEV1) was 11·1 percentage points (95% CI 8·4 to 13·7; both comparisons p<0·0001). Among 360 participants with no FDA-approved variant and no previous CFTR modulator, 177 (49%) were responders; in responders, mean absolute change in sweat chloride was -20·5 mmol/L (-17·2 to -23·8) and ppFEV1 was 13·2 percentage points (11·4 to 15·0; both comparisons p<0·0001). Among 36 participants who were receiving ivacaftor before elexacaftor-tezacaftor-ivacaftor, 32 (89%) continued elexacaftor-tezacaftor-ivacaftor. Of 251 individual CFTR variants, 64 (28 FDA-approved) were classified as responsive or possibly responsive to elexacaftor-tezacaftor-ivacaftor, and 123 (two FDA-approved) as non-responsive or possibly non-responsive to elexacaftor-tezacaftor-ivacaftor.

INTERPRETATION

In France, over half of the population with cystic fibrosis without a F508del variant responded to elexacaftor-tezacaftor-ivacaftor, with most responders having no FDA-approved variant. The treatment period was relatively short and further research is warranted to describe the long-term safety and effectiveness of elexacaftor-tezacaftor-ivacaftor in this population.

FUNDING

Association Vaincre la Mucoviscidose, Société Française de la Mucoviscidose, and Filière Maladies Rares MUCO-CFTR.

Cystic fibrosis

Cystic fibrosis is a rare genetic disease caused by mutations in CFTR, the gene encoding cystic fibrosis transmembrane conductance regulator (CFTR). The discovery of CFTR in 1989 has enabled the unravelling of disease mechanisms and, more recently, the development of CFTR-directed therapeutics that target the underlying molecular defect. The CFTR protein functions as an ion channel that is crucial for correct ion and fluid transport across epithelial cells lining the airways and other organs. Consequently, CFTR dysfunction causes a complex multi-organ disease but, to date, most of the morbidity and mortality in people with cystic fibrosis is due to muco-obstructive lung disease. Cystic fibrosis care has long been limited to treating symptoms using nutritional support, airway clearance techniques and antibiotics to suppress airway infection. The widespread implementation of newborn screening for cystic fibrosis and the introduction of a highly effective triple combination CFTR modulator therapy that has unprecedented clinical benefits in up to 90% of genetically eligible people with cystic fibrosis has fundamentally changed the therapeutic landscape and improved prognosis. However, people with cystic fibrosis who are not eligible based on their CFTR genotype or who live in countries where they do not have access to this breakthrough therapy remain with a high unmet medical need.

Beyond the 10%: Unraveling the genetic diversity in Turkish cystic fibrosis patients not eligible for CFTR modulators

BACKGROUND

Cystic fibrosis (CF) is an autosomal recessive disease caused by variants of CFTR gene. Over 2000 variants have been identified, and new drugs called CFTR modulators have been developed to target specific defects in the CFTR protein. However, these drugs are only suitable for patients with certain variants of CFTR, and eligibility rates vary depending on race and geographical region. This study aimed to reveal the detailed genotype and clinical characteristics of people with CF (pwCF) at our center in Turkey, a developing country, who are not eligible for CFTR modulators.

METHODS

A total of 445 pwCF followed up at Marmara University were reviewed retrospectively. Variants of the patients ineligible to CFTR modulators were classified based on American College of Medical Genetics guidelines, CFTR classification, the change in the encoded protein, and the variant type.

RESULTS

The study revealed that 139 (31.2%) patients weren't eligible for CFTR modulators. There were 60 different variants in the 276 alleles, as two were missing. The majority of patients had missense or nonsense variants, and that the most common variant was c.1545_1546del, which can be said unique to this geography.

CONCLUSION

The study highlights the importance of detecting the variants of ineligible patients in detail to guide future approaches for more targeted and effective interventions in CF care. Testing the effectiveness of CFTR modulators for rare or newly occurring variants is crucial to ensure equal access for pwCF to these therapies from different racial backgrounds and ethnic minorities.

xTrends in racial and ethnic disparities in pediatric lung transplantation in the United States

BACKGROUND

Racial and ethnic disparities in pediatric lung transplantation (LTx) related to the shifting cystic fibrosis (CF) population receiving highly effective modulator therapy (HEMT) has not been well investigated.

METHODS

The UNOS Registry was queried for patients age 1-25 years undergoing bilateral LTx between 1 January 2012 and 31 December 2021. Race and ethnicity were classified as non-Hispanic White, non-Hispanic Black, Hispanic, or none of the above. The primary outcome was posttransplant mortality. Trends in the association between race/ethnicity and mortality were examined using transplant year as a continuous variable and stratifying year based on introduction of HEMT (triple combination therapy) in November 2019.

RESULTS

In the study sample (N = 941), 7% of patients were non-Hispanic Black, 15% were Hispanic, and 2% were some other racial or ethnic group. One hundred (11%) received LTx after approval of triple combination therapy, and 407 (43%) died during follow-up. We identified a statistically significant disparity in mortality hazard (hazard ratio: 1.91; 95% confidence interval: 1.31, 2.80) in non-Hispanic Black compared to non-Hispanic White patients in the pre-triple combination therapy era.

CONCLUSIONS

We found higher mortality hazard among non-Hispanic Black compared to non-Hispanic White children undergoing LTx in the United States. Further monitoring of LTx outcomes to identify and address disparities is needed in the current era of triple combination therapy for CF.

Impact of sociodemographic status and sex on chronic rhinosinusitis and olfaction in people with cystic fibrosis

BACKGROUND

Sociodemographic status (SDS) including race/ethnicity and socioeconomic status as approximated by education, income, and insurance status impact pulmonary disease in people with cystic fibrosis (PwCF). The relationship between SDS and chronic rhinosinusitis (CRS) remains understudied.

METHODS

In a prospective, multi-institutional study, adult PwCF completed the 22-Question SinoNasal Outcome Test (SNOT-22), Smell Identification Test (SIT), Questionnaire of Olfactory Disorder Negative Statements (QOD-NS), and Cystic Fibrosis Questionnaire-Revised (CFQ-R). Lund-Kennedy scores, sinus computed tomography, and clinical data were collected. Data were analyzed across race/ethnicity, sex, and socioeconomic factors using multivariate regression.

RESULTS

Seventy-three PwCF participated with a mean age of 34.7 ± 10.9 years and 49 (67.1%) were female. Linear regression identified that elexacaftor/tezacaftor/ivacaftor (ETI) use (β = ‒4.09, 95% confidence interval [CI] [‒6.08, ‒2.11], p < 0.001), female sex (β = ‒2.14, 95% CI [‒4.11, ‒0.17], p = 0.034), and increasing age (β = ‒0.14, 95% CI [‒0.22, ‒0.05], p = 0.003) were associated with lower/better endoscopy scores. Private health insurance (β = 17.76, 95% CI [5.20, 30.32], p = 0.006) and >16 educational years (β = 13.50, 95% CI [2.21, 24.80], p = 0.020) were associated with higher baseline percent predicted forced expiratory volume in one second (ppFEV1). Medicaid/Medicare insurance was associated with worse endoscopy scores, CFQ-R respiratory scores, and ppFEV1 (all p < 0.017), and Hispanic/Latino ethnicity was associated with worse SNOT-22 scores (p = 0.047), prior to adjustment for other cofactors. No other SDS factors were associated with SNOT-22, QOD-NS, or SIT scores.

CONCLUSIONS

Differences in objective measures of CRS severity exist among PwCF related to sex, age, and ETI use. Variant status and race did not influence patient-reported CRS severity measures or olfaction in this study. Understanding how these factors impact response to treatment may improve care disparities among PwCF.

CLINICAL TRIALS

NCT04469439.

Increasing Diversity, Equity, Inclusion, and Accessibility in Rare Disease Clinical Trials

Diversity, equity, inclusion, and accessibility (DEIA) are foundational principles for clinical trials and medical research. In rare diseases clinical research, where numbers of participants are already challenged by rarity itself, maximizing inclusion is of particular importance to clinical trial success, as well as ensuring the generalizability and relevance of the trial results to the people affected by these diseases. In this article, we review the medical and gray literature and cite case examples to provide insights into how DEIA can be proactively integrated into rare diseases clinical research. Here, we particularly focus on genetic diversity. While the rare diseases DEIA literature is nascent, it is accelerating as many patient advocacy groups, professional societies, training and educational organizations, researcher groups, and funders are setting intentional strategies to attain DEIA goals moving forward, and to establish metrics to ensure continued improvement. Successful examples in underserved and underrepresented populations are available that can serve as case studies upon which rare diseases clinical research programs can be built. Rare diseases have historically been innovation drivers in basic, translational, and clinical research, and ultimately, all populations benefit from data diversity in rare diseases populations that deliver novel insights and approaches to how clinical research can be performed.

Improved detection of cystic fibrosis by the California Newborn Screening Program for all races and ethnicities

BACKGROUND

Newborn screening (NBS) for cystic fibrosis (CF) is universal in the United States. Protocols vary but include an immunoreactive trypsinogen (IRT) level and CFTR variant panel. California CF NBS has a 3-step screening: IRT level, variant panel, and CFTR sequencing if only one variant identified on panel.

METHODS

This was a cohort study of infants with CF born in California (2007-2021) to examine racial and ethnic differences in having a false-negative NBS result for CF and at which step the false-negative occurred. We examined how different CFTR variant panels would improve detection of variants by race and ethnicity: original 39-variant panel, current 75-variant panel, and all 402 disease-causing CFTR variants in the CFTR2 database.

RESULTS

Of the 912 infants born in California with CF, 84 had a false-negative result: 38 due to low IRT level and 46 with a high IRT value (but incomplete variant detection). Asian (OR 6.3) and Black infants (OR 2.5) were more likely to have a false-negative screening result than non-Hispanic white infants. The majority of false-negative screening (but CF diagnosis) cases among American Indian/Native Alaskan and non-Hispanic White infants were due to low IRT levels. The majority of Asian and Hispanic infants with false-negative screening had no variants detected. Detection of two CFTR variants was improved with the 75-variant panel in Black, Hispanic, and non-Hispanic White infants and with the 402-variant panel in Black, Hispanic, non-Hispanic White, and other race infants.

CONCLUSIONS

Larger CFTR panels in NBS improved the detection of CF in all races and ethnicities.

Implementation and evaluation of a fertility preservation telehealth counseling intervention for males with cystic fibrosis

BACKGROUND

Most males with cystic fibrosis (MwCF) have congenital bilateral absence of the vas deferens and require assisted reproductive technology to conceive, yet many have limited knowledge about how CF affects sexual and reproductive health (SRH). This study evaluates the feasibility, acceptability, and potential effectiveness of telehealth fertility preservation (FP) counseling for MwCF.

METHODS

Pre-lung transplant MwCF ≥18 years, recruited from U.S. CF centers, social media, and via snowball sampling, received individualized telehealth counseling. Participants completed intervention feasibility/acceptability one week post-counseling and FP knowledge, care satisfaction, and self-efficacy assessments at baseline and two months post-counseling. We completed acceptability interviews one-week post-counseling and audio-recorded, transcribed, and thematically analyzed results. We descriptively analyzed survey results and conducted pre/post comparisons using paired t-tests.

RESULTS

Thirty MwCF (ages 22-49 years) completed counseling. Most were in a relationship (70 %) and White (86.7 %). Telehealth FP counseling was acceptable (M = 4.38/5 ± 0.60), appropriate (M = 4.37/5 ± 0.60), and feasible (M = 4.60/5 ± 0.45) to MwCF. FP knowledge (9.53 vs. 10.40/12; p = .010), care satisfaction (20.23 vs 26.67/32; p<.001), and self-efficacy (22.87 vs 25.20/30; p = .016) improved at two months post-counseling. Despite desiring provider-initiated SRH, wanting children (81 %), and perceiving the CF team as their primary care provider (97 %), 44 % report not receiving information about infertility by the CF team.

CONCLUSIONS

Integrating FP counseling into CF care is feasible and acceptable to MwCF and can improve FP knowledge, self-efficacy, and care satisfaction. MwCF desire early and regular provider-initiated SRH education.

Highly effective cystic fibrosis transmembrane conductance (regulator) modulator therapy: shifting the curve for most while leaving some further behind

PURPOSE OF REVIEW

Traditional cystic fibrosis (CF) care had been focused on early intervention and symptom mitigation. With the advent of highly effective cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapy (HEMT), in particular, the approval of elexacaftor/tezacaftor/ivacaftor in 2019, there has been a dramatic improvement in outcomes in CF. The purpose of this article is to review the benefits, limitations, and impact of HEMT as well as discuss the new implications, challenges, and hope that modulators bring to people with CF (pwCF).

RECENT FINDINGS

HEMT has demonstrated sustained improvement in lung function, nutrition, quality of life, and survival for over 90% of pwCF. As HEMT has delivered such promise, there is a small but significant portion of pwCF who do not benefit from HEMT due to ineligible mutations, intolerance, or lack of accessibility to modulators.

SUMMARY

HEMT has significantly improved outcomes, but continued research is needed to understand the new challenges and implications the era of HEMT will bring, as well as how to provide equitable care to those who are unable to benefit from HEMT.

Racial inequities and rare CFTR variants: Impact on cystic fibrosis diagnosis and treatment

Cystic fibrosis (CF) has been traditionally viewed as a disease that affects White individuals. However, CF occurs among all races, ethnicities, and geographic ancestries. The disorder results from mutations in the CF transmembrane conductance regulator (CFTR). Varying incidence of CF is reported among Black, Indigenous, and People of Color (BIPOC), who typically exhibit worse clinical outcomes. These populations are more likely to carry rare CFTR variants omitted from newborn screening panels, leading to disparities in care such as delayed diagnosis and treatment. In this study, we present a case-in-point describing an individual of Gambian descent identified with CF. Patient genotype includes a premature termination codon (PTC) (c.2353C>T) and previously undescribed single nucleotide deletion (c.1970delG), arguing against effectiveness of currently available CFTR modulator-based interventions. Strategies for overcoming these two variants will likely include combinations of PTC suppressors, nonsense mediated decay inhibitors, and/or alternative approaches (e.g. gene therapy). Investigations such as the present study establish a foundation from which therapeutic treatments may be developed. Importantly, c.2353C>T and c.1970delG were not detected in the patient by traditional CFTR screening panels, which include an implicit racial and ethnic diagnostic bias as these tests are comprised of mutations largely observed in people of European ancestry. We suggest that next-generation sequencing of CFTR should be utilized to confirm or exclude a CF diagnosis, in order to equitably serve BIPOC individuals. Additional epidemiologic data, basic science investigations, and translational work are imperative for improving understanding of disease prevalence and progression, CFTR variant frequency, genotype-phenotype correlation, pharmacologic responsiveness, and personalized medicine approaches for patients with African ancestry and other historically understudied geographic lineages.

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").

The clinical utility of sequencing the entirety of CFTR

BACKGROUND

Cystic fibrosis (CF) is caused by deleterious variants in each CFTR gene. We investigated the utility of whole-gene CFTR sequencing when fewer than two pathogenic or likely pathogenic (P/LP) variants were detected by conventional testing (sequencing of exons and flanking introns) of CFTR.

METHODS

Individuals with features of CF and a CF-diagnostic sweat chloride concentration with zero or one P/LP variants identified by conventional testing enrolled in the CF Mutation Analysis Program (MAP) underwent whole-gene CFTR sequencing. Replication was performed on individuals enrolled in the CF Genome Project (CFGP), followed by phenotype review and interrogation of other genes.

RESULTS

Whole-gene sequencing identified a second P/LP variant in 20/43 MAP enrollees (47 %) and 10/22 CFGP enrollees (45 %) who had one P/LP variant after conventional testing. No P/LP variants were detected when conventional testing was negative (MAP: n = 43; CFGP: n = 13). Genome-wide analysis was unable to find an alternative etiology in CFGP participants with fewer than two P/LP CFTR variants and CF could not be confirmed in 91 % following phenotype re-review.

CONCLUSIONS

Whole-gene CFTR analysis is beneficial in individuals with one previously-identified P/LP variant and a CF-diagnostic sweat chloride. Negative conventional CFTR testing indicates that the phenotype should be re-evaluated.

Safety and efficacy of ivacaftor in infants aged 1 to less than 4 months with cystic fibrosis

BACKGROUND

Ivacaftor (IVA) has been shown to be safe and efficacious in children aged ≥4 months with cystic fibrosis (CF) and CFTR gating variants. We evaluated safety, pharmacokinetics (PK), and efficacy of IVA in a small cohort of infants aged 1 to <4 months with CF.

METHODS

In this phase 3, open-label study, infants 1 to <4 months with CF and an IVA-responsive CFTR variant received an initial low dose of IVA based on age and weight. Because IVA is a sensitive CYP3A substrate and CYP3A maturation is uncertain in infants, doses were adjusted at day 15 to better match median adult exposures based on individual PK measurements taken on day 4. Primary endpoints were safety and PK measurements.

RESULTS

Seven infants (residual function CFTR variants [n=5]; minimal function CFTR variants [n=2]) received ≥1 dose of IVA. Six infants had doses adjusted at day 15 and one infant did not require dose adjustment; subsequent PK analyses showed mean trough concentrations for IVA and metabolites were within range of prior clinical experience. Four infants (57.1%) had adverse events (AEs); no serious AEs were noted. One infant discontinued study drug due to a non-serious AE of elevated alanine aminotransferase >8x the upper limit of normal. Mean sweat chloride concentration decreased (-40.3 mmol/L [SD: 29.2]) through week 24. Improvements in biomarkers of pancreatic function and intestinal inflammation, as well as growth parameters, were observed.

CONCLUSIONS

In this small, open-label study, IVA dosing in infants achieved exposures previously shown to be safe and efficacious. Because PK was predictable, a dosing regimen based on age and weight is proposed. IVA was generally safe and well tolerated, and led to improvements in CFTR function, markers of pancreatic function and intestinal inflammation, and growth parameters, supporting use in infants as young as 1 month of age.

Investigating adverse genomic and regulatory changes caused by replacement of the full-length CFTR cDNA using Cas9 and AAV

A "universal strategy" replacing the full-length CFTR cDNA may treat >99% of people with cystic fibrosis (pwCF), regardless of their specific mutations. Cas9-based gene editing was used to insert the CFTR cDNA and a truncated CD19 (tCD19) enrichment tag at the CFTR locus in airway basal stem cells. This strategy restores CFTR function to non-CF levels. Here, we investigate the safety of this approach by assessing genomic and regulatory changes after CFTR cDNA insertion. Safety was first assessed by quantifying genetic rearrangements using CAST-seq. After validating restored CFTR function in edited and enriched airway cells, the CFTR locus open chromatin profile was characterized using ATAC-seq. The regenerative potential and differential gene expression in edited cells was assessed using scRNA-seq. CAST-seq revealed a translocation in ∼0.01% of alleles primarily occurring at a nononcogenic off-target site and large indels in 1% of alleles. The open chromatin profile of differentiated airway epithelial cells showed no appreciable changes, except in the region corresponding to the CFTR cDNA and tCD19 cassette, indicating no detectable changes in gene regulation. Edited stem cells produced the same types of airway cells as controls with minimal alternations in gene expression. Overall, the universal strategy showed minor undesirable genomic changes.

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.

Heterogeneity of CFTR modulator-induced sweat chloride concentrations in people with cystic fibrosis

BACKGROUND

Sweat chloride (SC) concentrations in people with cystic fibrosis (PwCF) reflect relative CF transmembrane conductance regulator (CFTR) protein function, the primary CF defect. Populations with greater SC concentrations tend to have lesser CFTR function and more severe disease courses. CFTR modulator treatment can improve CFTR function within specific CF genotypes and is commonly associated with reduced SC concentration. However, SC concentrations do not necessarily fall to concentrations seen in the unaffected population, suggesting potential for better CFTR treatment outcomes. We characterized post-modulator SC concentration variability among CHEC-SC study participants by genotype and modulator.

METHODS

PwCF receiving commercially approved modulators for ≥90 days were enrolled for a single SC measurement. Clinical data were obtained from chart review and the CF Foundation Patient Registry (CFFPR). Variability of post-modulator SC concentrations was assessed by cumulative SC concentration frequencies.

RESULTS

Post-modulator SC concentrations (n = 3787) were collected from 3131 PwCF; most (n = 1769, 47 %) were collected after elexacaftor/tezacaftor/ivacaftor (ETI) treatment. Modulator use was associated with lower SC distributions, with post-ETI concentrations the lowest on average. Most post-ETI SC concentrations were <60 mmol/L (79 %); 26 % were <30 mmol/L. Post-ETI distributions varied by genotype. All genotypes containing at least one F508del allele had individuals with post-ETI SC ≥60 mmol/L, with the largest proportion being F508del/minimal function (31 %).

CONCLUSIONS

Post-modulator SC concentration heterogeneity was observed among all genotypes and modulators, including ETI. The presence of PwCF with post-modulator SC concentrations within the CF diagnostic range suggests room for additional treatment-associated CFTR restoration in this population.

Child Health and the US Pediatric Subspecialty Workforce: Planning for the Future

This article opens a multi-article Pediatrics supplement that provides a rigorous analysis of the projected pediatric subspecialty workforce in the United States. Congenital variations, epigenetics, exposures, lifestyle, preventive care, and medical interventions from conception through young adulthood set the stage for health and wellbeing in adulthood. Although care provided by pediatric subspecialists is associated with better outcomes and lower costs compared with adult providers, the authors of recent articles in the lay and medical literature have questioned the capacity of pediatric subspecialists to meet children's health care needs. This article highlights that, despite numerous advances in prevention, diagnosis, and treatment, the last decade has witnessed increasing numbers of children with acute or chronic physical and mental health disorders, including medical complexity, obesity, type 2 diabetes, anxiety, depression, and suicidality, all of which are exacerbated by poverty, racism, and other social drivers of health. In this article, we then describe the variability in the demographics, practice characteristics, and geographic distribution of the 15 core pediatric subspecialties certified by the American Board of Pediatrics. We then discuss the rationale and approach to the development of a pediatric subspecialty workforce model that forecasts subspecialist supply from 2020 to 2040 for 14 subspecialties at the national and subnational levels (not including the newest subspecialty, pediatric hospital medicine), accounting for US Census Bureau child population projections. The model does not account for the unique physical and mental needs of individual children, nor does it address the increasingly precarious commitment to, and financing of, pediatric subspecialty care in the US health care system impacting market demand.

Laboratory Tools to Predict CFTR Modulator Therapy Effectiveness and to Monitor Disease Severity in Cystic Fibrosis

The implementation of cystic fibrosis (CF) transmembrane conductance regulator (CFTR) modulator drugs into clinical practice has been attaining remarkable therapeutic outcomes for CF, a life-threatening autosomal recessive genetic disease. However, there is elevated CFTR allelic heterogeneity, and various individuals carrying (ultra)rare CF genotypes remain without any approved modulator therapy. Novel translational model systems based on individuals' own cells/tissue are now available and can be used to interrogate in vitro CFTR modulator responses and establish correlations of these assessments with clinical features, aiming to provide prediction of therapeutic effectiveness. Furthermore, because CF is a progressive disease, assessment of biomarkers in routine care is fundamental in monitoring treatment effectiveness and disease severity. In the first part of this review, we aimed to focus on the utility of individual-derived in vitro models (such as bronchial/nasal epithelial cells and airway/intestinal organoids) to identify potential responders and expand personalized CF care. Thereafter, we discussed the usage of CF inflammatory biomarkers derived from blood, bronchoalveolar lavage fluid, and sputum to routinely monitor treatment effectiveness and disease progression. Finally, we summarized the progress in investigating extracellular vesicles as a robust and reliable source of biomarkers and the identification of microRNAs related to CFTR regulation and CF inflammation as novel biomarkers, which may provide valuable information for disease prognosis.

How representative are clinical trial cohorts of the general CF population? Implications for trial planning

Understanding the number of patients eligible to participate in research is important to design protocols and define research priorities. We reviewed the records of all patients with CF, age 12+, who receive care at our centre. We assessed their eligibility for trial participation based on common trial inclusion/exclusion criteria. 643 patients were included in the analysis, 31 were modulator ineligible(MI). Only 198(31 %) of the total cohort and 7(23 %) of the MI cohort were eligible for participation based on the hypothetical criteria. The most common reason for ineligibility was ppFEV1 ≥90 % followed by clinical instability, complex comorbidity and anticipated inability to adhere to the protocol. We suggest this would be a useful exercise for centres planning to either participate in, or refer subjects into, upcoming trials to undertake for their own cohort. We also make suggestions for protocol designs that optimise the number of patients who are eligible to participate.

Health inequities in the modulator era

PURPOSE OF REVIEW

To discuss the existing health inequities in people with cystic fibrosis (CF) and how the recent development of cystic fibrosis transmembrane regulator (CFTR) modulators may impact these inequities.

RECENT FINDINGS

People with CF (pwCF) from low socioeconomic status (SES) have more pulmonary exacerbations, worse nutritional status, lower pulmonary function, and an increased mortality rate with less access to lung transplantation. pwCF who identify as racial and ethnic minorities have earlier mortality, lower lung function, are less likely to be detected on newborn screening resulting in a delayed diagnosis, are underrepresented in clinic trials, and less likely to be eligible for a CFTR modulator. Female sex is associated with more pulmonary exacerbations and earlier mortality. Sexual gender minorities are a vulnerable population with worse health outcomes, and more research is needed in CF. CFTR modulators are inaccessible to low to middle-income countries due to significant cost burden.

SUMMARY

People with CF from low SES, racial and ethnic minorities, female sex, and sexual gender minorities face health inequities. CFTR modulator use will further widen existing health inequities given the unequal access to modulators based on nonqualifying genetics and exorbitant cost restricting use both on an individual and global level.

The Lived Experience of African American Persons with Cystic Fibrosis

Background: Cystic fibrosis (CF) is a rare genetic disease affecting approximately 30,000 people in the United States (US). African American persons with CF are even rarer, comprising approximately 5% of this population. Purpose: The purpose of this study was to explore the lived experiences of African American persons with CF to identify potential disparities in health care. Methods: Descriptive phenomenology was used to explore lived experiences of African American persons with CF over age 18 recruited from CF Foundation-accredited Centers in the US, CF-specific social media, and via snowball sampling. Study data was obtained through telephone interviews that were audio-recorded, transcribed verbatim, and analyzed using Colaizzi's method of thematic analysis. Results: Six men and six women (ages 23-45) completed the study. Interviews revealed three themes: (1) Accepting a Diagnosis of CF; (2) Desiring a Normal Life while Living with an Invisible Disease; and 3) A Slippery Slope of Subtle Racism. Each theme had 2-3 subthemes. Conclusions: It is critical to explore the unique challenges faced by African American persons with CF in order to develop interventions that improve their daily lives and create better futures. Implications for Practice: Findings highlight the unique challenges faced by underrepresented groups with CF and the need to address health inequities to improve care delivery.

Advancing the pipeline of cystic fibrosis clinical trials: a new roadmap with a global trial network perspective

The growing use of modulator therapies aimed at restoring cystic fibrosis transmembrane conductance regulator (CFTR) protein function in people with cystic fibrosis has fundamentally altered clinical trial strategies needed to advance new therapeutics across an orphan disease population that is now divided by CFTR modulator eligibility. The development of a robust pipeline of nucleic acid-based therapies (NABTs)-initially directed towards the estimated 10% of the cystic fibrosis population who are genetically ineligible for, or intolerant of, CFTR modulators-is dependent on the optimisation of restricted trial participant resources across multiple development programmes, a challenge that will preclude the use of gold standard placebo-controlled trials. Advancement of a full pipeline of symptomatic therapies across the entire cystic fibrosis population will be challenged by smaller effect sizes and uncertainty regarding their clinical importance in a growing modulator-treated population with more mild and stable pulmonary disease. In this Series paper, we aim to lay the foundation for clinical trial strategy and community partnership that must deviate from established and familiar precedent to advance the future pipeline of cystic fibrosis therapeutics.

The future of cystic fibrosis treatment: from disease mechanisms to novel therapeutic approaches

With the 2019 breakthrough in the development of highly effective modulator therapy providing unprecedented clinical benefits for over 90% of patients with cystic fibrosis who are genetically eligible for treatment, this rare disease has become a front runner of transformative molecular therapy. This success is based on fundamental research, which led to the identification of the disease-causing CFTR gene and our subsequent understanding of the disease mechanisms underlying the pathogenesis of cystic fibrosis, working together with a continuously evolving clinical research and drug development pipeline. In this Series paper, we focus on advances since 2018, and remaining knowledge gaps in our understanding of the molecular mechanisms of CFTR dysfunction in the airway epithelium and their links to mucus dysfunction, impaired host defences, airway infection, and chronic inflammation of the lungs of people with cystic fibrosis. We review progress in (and the remaining obstacles to) pharmacological approaches to rescue CFTR function, and novel strategies for improved symptomatic therapies for cystic fibrosis, including how these might be applicable to common lung diseases, such as bronchiectasis and chronic obstructive pulmonary disease. Finally, we discuss the promise of genetic therapies and gene editing approaches to restore CFTR function in the lungs of all patients with cystic fibrosis independent of their CFTR genotype, and the unprecedented opportunities to transform cystic fibrosis from a fatal disease to a treatable and potentially curable one.

CFTR modulator therapy: transforming the landscape of clinical care in cystic fibrosis

Following discovery of the cystic fibrosis transmembrane conductance regulator (CFTR) gene in 1989 and subsequent elucidation of the varied CFTR protein abnormalities that result, a new era of cystic fibrosis management has emerged-one in which scientific principles translated from the bench to the bedside have enabled us to potentially treat the basic defect in the majority of children and adults with cystic fibrosis, with a resultant burgeoning adult cystic fibrosis population. However, the long-term effects of these therapies on the multiple manifestations of cystic fibrosis are still under investigation. Understanding the effects of modulators in populations excluded from clinical trials is also crucial. Furthermore, establishing appropriate disease measures to assess efficacy in the youngest potential trial participants and in those whose post-modulator lung function is in the typical range for people without chronic lung disease is essential for continued drug development. Finally, recognising that a health outcome gap has been created for some people and widened for others who are not eligible for, cannot tolerate, or do not have access to modulators is important.

Social Determinants of Genetics Referral and Completion Rates Among Child Neurology Patients

Objective

To investigate clinical, social, and systems-level determinants predictive of genetics clinic referral and completion of genetics clinic visits among child neurology patients.

Methods

Electronic health record data were extracted from patients 0-18 years old who were evaluated in child neurology clinics at a single tertiary care institution between July 2018 to January 2020. Variables aligned with the Health Equity Implementation Framework. Referral and referral completion rates to genetics and cardiology clinics were compared among Black vs White patients using bivariate analysis. Demographic variables associated with genetics clinic referral and visit completion were identified using logistic regressions.

Results

In a cohort of 11,371 child neurology patients, 304 genetics clinic referrals and 82 cardiology clinic referrals were placed. In multivariate analysis of patients with Black or White ethnoracial identity (n=10,601), genetics clinic referral rates did not differ by race, but were significantly associated with younger age, rural address, neurodevelopmental disorder diagnosis, number of neurology clinic visits, and provider type. The only predictors of genetics clinic visit completion number of neurology clinic visits and race/ethnicity, with White patients being twice as likely as Black patients to complete the visit. Cardiology clinic referrals and visit completion did not differ by race/ethnicity.

Interpretation

Although race/ethnicity was not associated with differences in genetics clinic referral rates, White patients were twice as likely as Black patients to complete a genetics clinic visit after referral. Further work is needed to determine whether this is due to systemic/structural racism, differences in attitudes toward genetic testing, or other factors.

Cystic fibrosis-related mortality in the United States from 1999 to 2020: an observational analysis of time trends and disparities

Cystic fibrosis transmembrane conductance regulator modulators have revolutionized cystic fibrosis (CF) care in the past decade. This study explores the CF-related mortality trends in the US from 1999 to 2020. We extracted CF-related mortality data from the CDC WONDER database. CF age-standardized mortality rates (ASMRs) were identified by ICD-10 code E84 and were stratified by demographic and geographical variables. Temporal trends were analyzed using Joinpoint modeling. CF-related ASMRs decreased from 1.9 to 1.04 per million population (p = 0.013), with a greater reduction in recent years. This trend was replicated in both sexes. The median age of death increased from 24 to 37 years. CF mortality rates decreased across sex, white race, non-Hispanic ethnicity, census regions, and urbanization status. Incongruent trends were reported in non-white races and Hispanic ethnicity. A lower median age of death was observed in women, non-white races, and Hispanic ethnicity. SARS-CoV-2 infection was the primary cause of death in 1.7% of CF decedents in 2020. The national CF-related mortality rates declined and the median age of death among CF decedents increased significantly indicating better survival in the recent years. The changes were relatively slow during the earlier period of the study, followed by a greater decline lately. We observed patterns of sex, ethnic, racial, and geographical disparities associated with the worsening of the gap between ethnicities, narrowing of the gap between races and rural vs. urban counties, and closing of the gap between sexes over the study period.

Defining and Promoting Pediatric Pulmonary Health: Developing Biomarkers for Pulmonary Health

Children with inherited and/or acquired respiratory disorders often arrive in adolescence and adulthood with diminished lung function that might have been detected and prevented had better mechanisms been available to identify and to assess progression of disease. Fortunately, advances in genetic assessments, low-cost diagnostics, and minimally- invasive novel biomarkers are being developed to detect and to treat respiratory diseases before they give rise to loss of life or lung function. This paper summarizes the Developing Biomarkers for Pulmonary Health sessions of the National Heart, Lung, and Blood Institute- sponsored 2021 Defining and Promoting Pediatric Pulmonary Health workshop. These sessions discussed genetic testing, pulse oximetry, exhaled nitric oxide, and novel biomarkers related to childhood lung diseases.

Aiming to Improve Equity in Pulmonary Health: Cystic Fibrosis

This review summarizes the evidence of health disparities in cystic fibrosis (CF), an autosomal recessive genetic disorder with substantial variation in disease progression and outcomes. We review disparities by race, ethnicity, socioeconomic status, geographic location, gender identity, or sexual orientation documented in the literature. We outline the mechanisms that generate and perpetuate such disparities across levels and domains of influence and assess the implications of this evidence. We then recommend strategies for improving equity in CF outcomes, drawing on recommendations for the general population and considering approaches specific to people living with CF.

Ethnic differences in staphylococcus aureus acquisition in cystic fibrosis

BACKGROUND

Hispanic people with CF (pwCF) have increased morbidity than non-Hispanic White pwCF, including increased risk of Pseudomonas aeruginosa. We aimed to determine if Staphylococcus aureus (S. aureus) acquisition varies between Hispanic and non-Hispanic White pwCF.

METHODS

This longitudinal cohort study of pwCF ages 0-25 years in the CF Foundation Patient Registry compared acquisition of methicillin-sensitive S. aureus (MSSA), methicillin-resistant S. aureus (MRSA), persistent MRSA between Hispanic and non-Hispanic White pwCF. Risk of acquisition was assessed by Kaplan-Meier survival curves and its association with ethnicity was evaluated using Cox regressions. Adjusted associations were evaluated using multivariate Cox models adjusting for sex, age of entry into CFFPR, CFTR variant severity, pancreatic insufficiency, CF-related diabetes, maternal education, insurance status.

RESULTS

Of 10,640 pwCF, 7.5% were Hispanic and 92.5% were non-Hispanic White. Hispanic pwCF had a 19% higher risk of acquiring MSSA (HR 1.19, 95% CI 1.10-1.28, p<0.001) and 13% higher risk of acquiring MRSA (HR 1.13, 95% CI 1.02-1.26, p = 0.02) than non-Hispanic White pwCF. The difference in persistent MRSA between ethnicities did not reach statistical significance. After adjusting for confounding variables, only the risk of MSSA was significantly associated with ethnicity. Compared to non-Hispanic White pwCF, Hispanic pwCF acquired MSSA and MRSA at younger median ages (4.9 vs. 3.8 years (p<0.001), 22.4 vs. 20.8 years (p = 0.02).

CONCLUSION

Hispanic pwCF <25 years of age have an increased risk of acquiring MSSA and acquired MSSA and MRSA at an earlier age. Differences in S. aureus acquisition may contribute to increased morbidity in Hispanic pwCF.

Parent and adolescent perceptions of cystic fibrosis management responsibility: A mixed-methods study

BACKGROUND

Adolescents with cystic fibrosis (CF) and their parents must navigate changing roles and responsibilities within the family including transfer of disease management responsibilities.

AIM/OBJECTIVE

The aim of this qualitative study was to explore how families share and transfer CF management responsibility from the perspectives of adolescents with CF and their parents.

METHODS

Guided by qualitative descriptive methodology, we purposively sampled adolescent/parent dyads. Participants completed two surveys measuring family responsibility (Family Responsibility Questionnaire [FRQ]) and transition readiness (Transition Readiness Assessment Questionnaire [TRAQ]) We conducted semistructured video or phone interviews, used a codebook to guide team coding and analyzed qualitative data using both content analysis and dyadic interview analysis.

RESULTS

Thirty participants (15 dyads) enrolled (7% Black; 33% Latina/o; 40% female; adolescent age 14.4 ± 2 years; 66% prescribed highly effective modulator therapy; 80% of parents were mothers). Parent FRQ and TRAQ scores were significantly higher than their adolescent indicating differing perceptions of responsibility and transition readiness. We inductively identified four themes: (1) CF management is a delicate balance (CF management is a routine which is easily disrupted), (2) Growing up and parenting under extraordinary circumstances (the burden of CF weighs on families as they navigate adolescence), (3) Differing Perceptions of risk and responsibility (adolescent and parent perceptions of treatment responsibility and the risks of nonadherence do not always align), and (4) Balancing independence and protection (families must weigh the benefits and risks of allowing adolescents increased independence).

CONCLUSIONS

Adolescents and parents demonstrated differing perceptions of CF management responsibility, which may be related to a lack of communication between family members about this topic. To help facilitate alignment of parent and adolescent expectations, discussion of family roles and responsibility for CF management should begin early during the transition process and be discussed regularly during clinic visits.

Effects of Lumacaftor/Ivacaftor on Cystic Fibrosis Disease Progression in Children 2 through 5 Years of Age Homozygous for F508del-CFTR: A Phase 2 Placebo-controlled Clinical Trial

Rationale: Lumacaftor/ivacaftor (LUM/IVA) was shown to be safe and well tolerated in children 2 through 5 years of age with cystic fibrosis (CF) homozygous for F508del-CFTR in a Phase 3 open-label study. Improvements in sweat chloride concentration, markers of pancreatic function, and lung clearance index2.5 (LCI2.5), along with increases in growth parameters, suggested the potential for early disease modification with LUM/IVA treatment. Objective: To further assess the effects of LUM/IVA on CF disease progression in children 2 through 5 years of age using chest magnetic resonance imaging (MRI). Methods: This Phase 2 study had two parts: a 48-week, randomized, double-blind, placebo-controlled treatment period in which children 2 through 5 years of age with CF homozygous for F508del-CFTR received either LUM/IVA or placebo (Part 1) followed by an open-label period in which all children received LUM/IVA for an additional 48 weeks (Part 2). The results from Part 1 are reported. The primary endpoint was absolute change from baseline in chest MRI global score at Week 48. Secondary endpoints included absolute change in LCI2.5 through Week 48 and absolute changes in weight-for-age, stature-for-age, and body mass index-for-age z-scores at Week 48. Additional endpoints included absolute changes in sweat chloride concentration, fecal elastase-1 levels, serum immunoreactive trypsinogen, and fecal calprotectin through Week 48. The primary endpoint was analyzed using Bayesian methods, where the actual Bayesian posterior probability of LUM/IVA being superior to placebo in the chest MRI global score at Week 48 was calculated using a vague normal prior distribution; secondary and additional endpoints were analyzed using descriptive summary statistics. Results: Fifty-one children were enrolled and received LUM/IVA (n = 35) or placebo (n = 16). For the change in chest MRI global score at Week 48, the Bayesian posterior probability of LUM/IVA being better than placebo (treatment difference, <0; higher score indicates greater abnormality) was 76%; the mean treatment difference was -1.5 (95% credible interval, -5.5 to 2.6). Treatment with LUM/IVA also led to within-group numerical improvements in LCI2.5, growth parameters, and biomarkers of pancreatic function as well as greater decreases in sweat chloride concentration compared with placebo from baseline through Week 48. Safety data were consistent with the established safety profile of LUM/IVA. Conclusions: This placebo-controlled study suggests the potential for early disease modification with LUM/IVA treatment, including that assessed by chest MRI, in children as young as 2 years of age. Clinical trial registered with www.clinicaltrials.gov (NCT03625466).

Diagnostic and Communication Challenges in Cystic Fibrosis Newborn Screening

As of December 2009, cystic fibrosis (CF) newborn screening (NBS) is performed in all 50 US states and the District of Columbia. Widespread implementation of CF newborn screening (CFNBS) in the US and internationally has brought about new and varied challenges. Immunoreactive trypsinogen (IRT) remains the first, albeit imperfect, biomarker used universally in the screening process. Advances in genetic testing have provided an opportunity for newborn screening programs to add CFTR sequencing tiers to their algorithms. This in turn will enable earlier identification of babies with CF and improve longer-term outcomes through prompt treatment and intervention. CFTR sequencing has led to the ability to identify infants with CF from diverse ethnic and racial backgrounds more equitably while also identifying an increasing proportion of infants with inconclusive diagnoses. Using the evolution of the New York State CF newborn screening program as a guide, this review outlines the basic steps in a universal CF newborn screening program, considers how to reduce bias, highlights challenges, offers guidance to address these challenges and provides recommendations for future consideration.

Establishing a Cystic Fibrosis Learning Network: Interventions to promote collaboration and data-driven improvement at scale

Introduction

A learning health network is a type of learning health system in which stakeholders use network organization to improve health and health care. Building on existing resources in the cystic fibrosis (CF) community, the Cystic Fibrosis Learning Network (CFLN) was designed to improve medical outcomes and quality of life through an intentional focus on achieving reliable evidence-based chronic care delivery and creating a system for data-driven collaborative learning.

Methods

We describe the development and growth of the CFLN considering six domains of a Network Maturity Grid: system leadership; governance and policy management; quality improvement (QI); engagement and community building; data and analytics; and research. We illustrate the impact of the CFLN experience on chronic care processes and indicators of collaborative infrastructure.

Results

The CFLN represents 36 accredited care centers in the CF Foundation Care Center Network caring for over 6300 patients. Of 6779 patient clinical care visits/quarter, 77% are entered into the CF Foundation Patient Registry within 30 days, providing timely means to track outcomes. Collaborative visit planning is occurring in 93% of clinical care visits to share agenda setting with patients and families. Almost all CFLN teams (94%, n = 34) have a patient/family partner (PFP), and 74% of PFPs indicate they are actively participating, taking ownership of, or leading QI initiatives with the interdisciplinary care team. In 2022, 97% of centers reported completing 1-13 improvement cycles per month, and 82% contributed to monthly QI progress reports to share learning.

Conclusion

The CFLN is a maturing, collaborative infrastructure. CFLN centers practice at an advanced level of coproduction. The CFLN fosters interdisciplinary and PFP leadership and the performance of consistent data-driven improvement cycles. CFLN centers are positioned to respond to rapid changes in evidence-based care and advance the practice of QI and implementation science on a broader scale.

Inhaled mRNA therapy for treatment of cystic fibrosis: Interim results of a randomized, double-blind, placebo-controlled phase 1/2 clinical study

BACKGROUND

MRT5005, a codon-optimized CFTR mRNA, delivered by aerosol in lipid nanoparticles, was designed as a genotype-agnostic treatment for CF lung disease.

METHODS

This was a randomized, double-blind, placebo-controlled Phase 1/2 study performed in the US. Adults with 2 severe class I and/or II CFTR mutations and baseline ppFEV1 values between 50 and 90% were randomized 3:1 (MRT5005: placebo). Six dose levels of MRT5005 (4, 8, 12, 16, 20, and 24 mg) or placebo (0.9% Sodium Chloride) were administered by nebulization. The single ascending dose cohort was treated over a range from 8 to 24 mg; the multiple ascending dose cohort received five weekly doses (range 8-20 mg); and the daily dosing cohort received five daily doses (4 mg).

RESULTS

A total of 42 subjects were assigned to MRT5005 [31] or placebo [11]. A total of 14 febrile reactions were observed in 10 MRT5005-treated participants, which were mild [3] or moderate [11] in severity; two subjects discontinued related to these events. Additionally, two MRT5005-treated patients experienced hypersensitivity reactions, which were managed conservatively. The most common treatment emergent adverse events were cough and headache. No consistent effects on FEV1 were noted.

CONCLUSIONS

MRT5005 was generally safe and well tolerated through 28 days of follow-up after the last dose, though febrile and hypersensitivity reactions were noted. The majority of these reactions resolved within 1-2 days with supportive care allowing continued treatment with MRT5005 and careful monitoring. In this small first-in-human study, FEV1 remained stable after treatment, but no beneficial effects on FEV1 were observed.

Medical traumatic stress in cystic fibrosis: A qualitative analysis

BACKGROUND

People living with cystic fibrosis (PwCF) face a lifetime of potentially traumatic illness-related experiences that can lead to posttraumatic stress symptoms. Existing criteria for this type of posttraumatic stress, called medical traumatic stress (MTS), may not fully capture the CF experience. In this study we aimed to explore: 1) illness-related experiences perceived as traumatic in the setting of CF, 2) perceived MTS symptoms in PwCF, and 3) perceived health-related functional impairments from MTS.

METHODS

Informed by our aims, we developed and piloted guides for semi-structured interviews and focus groups with PwCF, family members of PwCF, and CF medical providers. We then conducted a series of interviews and focus groups. The qualitative analytical process followed Deterding and Waters' three stages of flexible coding for in-depth interviews, generating key themes and sub-themes in each domain of study inquiry.

RESULTS

We recruited 51 participants, including 24 PwCF, 7 family members of PwCF, and 20 CF care team members. Illness-related experiences perceived as traumatic were often characterized by themes of loss of agency, threats of bodily harm, and shifts in identity. Prominent MTS symptoms included shame, survivor guilt, burden guilt, germaphobia, and symptom panic. Health-related themes of functional impairments perceived to result from MTS included poor adherence and strained relationships between providers and patients/families.

CONCLUSIONS

This is the first study to explore the specific experiences of MTS in PwCF. It highlights the need for screening that includes these specific exposure types and symptoms, which may be mitigatable with medical trauma-focused interventions.

Furin as a therapeutic target in cystic fibrosis airways disease

Clinical management of cystic fibrosis (CF) has been greatly improved by the development of small molecule modulators of the CF transmembrane conductance regulator (CFTR). These drugs help to address some of the basic genetic defects of CFTR; however, no suitable CFTR modulators exist for 10% of people with CF (PWCF). An alternative, mutation-agnostic therapeutic approach is therefore still required. In CF airways, elevated levels of the proprotein convertase furin contribute to the dysregulation of key processes that drive disease pathogenesis. Furin plays a critical role in the proteolytic activation of the epithelial sodium channel; hyperactivity of which causes airways dehydration and loss of effective mucociliary clearance. Furin is also responsible for the processing of transforming growth factor-β, which is increased in bronchoalveolar lavage fluid from PWCF and is associated with neutrophilic inflammation and reduced pulmonary function. Pathogenic substrates of furin include Pseudomonas exotoxin A, a major toxic product associated with Pseudomonas aeruginosa infection and the spike glycoprotein of severe acute respiratory syndrome coronavirus 2, the causative pathogen for coronavirus disease 2019. In this review we discuss the importance of furin substrates in the progression of CF airways disease and highlight selective furin inhibition as a therapeutic strategy to provide clinical benefit to all PWCF.

Safety and efficacy of vanzacaftor-tezacaftor-deutivacaftor in adults with cystic fibrosis: randomised, double-blind, controlled, phase 2 trials

BACKGROUND

Elexacaftor-tezacaftor-ivacaftor has been shown to be safe and efficacious in people with cystic fibrosis and at least one F508del allele. Our aim was to identify a novel cystic fibrosis transmembrane conductance regulator (CFTR) modulator combination capable of further increasing CFTR-mediated chloride transport, with the potential for once-daily dosing.

METHODS

We conducted two phase 2 clinical trials to assess the safety and efficacy of a once-daily combination of vanzacaftor-tezacaftor-deutivacaftor in participants with cystic fibrosis who were aged 18 years or older. A phase 2 randomised, double-blind, active-controlled study (VX18-561-101; April 17, 2019, to Aug 20, 2020) was carried out to compare deutivacaftor monotherapy with ivacaftor monotherapy in participants with CFTR gating mutations, following a 4-week ivacaftor monotherapy run-in period. Participants were randomly assigned to receive either ivacaftor 150 mg every 12 h, deutivacaftor 25 mg once daily, deutivacaftor 50 mg once daily, deutivacaftor 150 mg once daily, or deutivacaftor 250 mg once daily in a 1:1:2:2:2 ratio. The primary endpoint was absolute change in ppFEV1 from baseline at week 12. A phase 2 randomised, double-blind, controlled, proof-of-concept study of vanzacaftor-tezacaftor-deutivacaftor (VX18-121-101; April 30, 2019, to Dec 10, 2019) was conducted in participants with cystic fibrosis and heterozygous for F508del and a minimal function mutation (F/MF genotypes) or homozygous for F508del (F/F genotype). Participants with F/MF genotypes were randomly assigned 1:2:2:1 to receive either 5 mg, 10 mg, or 20 mg of vanzacaftor in combination with tezacaftor-deutivacaftor or a triple placebo for 4 weeks, and participants with the F/F genotype were randomly assigned 2:1 to receive either vanzacaftor (20 mg)-tezacaftor-deutivacaftor or tezacaftor-ivacaftor active control for 4 weeks, following a 4-week tezacaftor-ivacaftor run-in period. Primary endpoints for part 1 and part 2 were safety and tolerability and absolute change in ppFEV1 from baseline to day 29. Secondary efficacy endpoints were absolute change from baseline at day 29 in sweat chloride concentrations and Cystic Fibrosis Questionnaire-Revised (CFQ-R) respiratory domain score. These clinical trials are registered with ClinicalTrials.gov, NCT03911713 and NCT03912233, and are complete.

FINDINGS

In study VX18-561-101, participants treated with deutivacaftor 150 mg once daily (n=23) or deutivacaftor 250 mg once daily (n=24) had mean absolute changes in ppFEV1 of 3·1 percentage points (95% CI -0·8 to 7·0) and 2·7 percentage points (-1·0 to 6·5) from baseline at week 12, respectively, versus -0·8 percentage points (-6·2 to 4·7) with ivacaftor 150 mg every 12 h (n=11); the deutivacaftor safety profile was consistent with the established safety profile of ivacaftor 150 mg every 12 h. In study VX18-121-101, participants with F/MF genotypes treated with vanzacaftor (5 mg)-tezacaftor-deutivacaftor (n=9), vanzacaftor (10 mg)-tezacaftor-deutivacaftor (n=19), vanzacaftor (20 mg)-tezacaftor-deutivacaftor (n=20), and placebo (n=10) had mean changes relative to baseline at day 29 in ppFEV1 of 4·6 percentage points (-1·3 to 10·6), 14·2 percentage points (10·0 to 18·4), 9·8 percentage points (5·7 to 13·8), and 1·9 percentage points (-4·1 to 8·0), respectively, in sweat chloride concentration of -42·8 mmol/L (-51·7 to -34·0), -45·8 mmol/L (95% CI -51·9 to -39·7), -49·5 mmol/L (-55·9 to -43·1), and 2·3 mmol/L (-7·0 to 11·6), respectively, and in CFQ-R respiratory domain score of 17·6 points (3·5 to 31·6), 21·2 points (11·9 to 30·6), 29·8 points (21·0 to 38·7), and 3·3 points (-10·1 to 16·6), respectively. Participants with the F/F genotype treated with vanzacaftor (20 mg)-tezacaftor-deutivacaftor (n=18) and tezacaftor-ivacaftor (n=10) had mean changes relative to baseline (taking tezacaftor-ivacaftor) at day 29 in ppFEV1 of 15·9 percentage points (11·3 to 20·6) and -0·1 percentage points (-6·4 to 6·1), respectively, in sweat chloride concentration of -45·5 mmol/L (-49·7 to -41·3) and -2·6 mmol/L (-8·2 to 3·1), respectively, and in CFQ-R respiratory domain score of 19·4 points (95% CI 10·5 to 28·3) and -5·0 points (-16·9 to 7·0), respectively. The most common adverse events overall were cough, increased sputum, and headache. One participant in the vanzacaftor-tezacaftor-deutivacaftor group had a serious adverse event of infective pulmonary exacerbation and another participant had a serious rash event that led to treatment discontinuation. For most participants, adverse events were mild or moderate in severity.

INTERPRETATION

Once-daily dosing with vanzacaftor-tezacaftor-deutivacaftor was safe and well tolerated and improved lung function, respiratory symptoms, and CFTR function. These results support the continued investigation of vanzacaftor-tezacaftor-deutivacaftor in phase 3 clinical trials compared with elexacaftor-tezacaftor-ivacaftor.

FUNDING

Vertex Pharmaceuticals.

Disparities and therapeutic advances in cystic fibrosis

Cystic fibrosis (CF) has seen a multitude of therapeutic advances targeting its downstream effects. This has led to a steady increase in survival over the past few decades. The recent development of disease-modifying drugs targeting the underlying CFTR mutation has revolutionized treatment for CF. Despite these advances, individuals with CF who are racial and ethnic minorities, from low socioeconomic status, or female sex have worse clinical outcomes. The inequitable access to CFTR modulators from cost and/or genetic eligibility has the potential to further worsen the existing health disparities seen within the CF community.

Racial and ethnic differences in patients enrolled in the national bronchiectasis and nontuberculous mycobacteria research registry

Demographic and socioeconomic factors are recognized to contribute to disparities in healthcare outcomes. Originally, bronchiectasis was described in a population of predominantly White ethnic group of patients in which racial disparity could not be identified. The U.S. Bronchiectasis Research Registry (BRR), a centralized database of adult patients with bronchiectasis and/or NTM from 18 clinical institutions across the U.S., was created to support the research of this condition. The aim of this study is to describe the racial and ethnic distribution of patients enrolled in the BRR and evaluate factors associated with healthcare disparities within manifestations of and/or the care delivered to this population. At the time of this study, 3600 patients with bronchiectasis and/or NTM were enrolled in the BRR. Of those, 3510 participants were included in these analyses. The population was predominantly non-HispanicWhite (n = 3143, 89.5%), followed by Hispanic or Latino (n = 149, 4.3%), Asian (n = 130, 3.7%) and non-Hispanic Black (n = 88, 2.5%) participants. Testing for cystic fibrosis, immunoglobulin deficiency, and mycobacteria was not different between races, but non-Hispanic Black patients were tested less frequently for alpha-1 antitrypsin (A1AT) deficiency compared to other groups (P = 0.01). The four groups did not differ in the proportion of Pseudomonas aeruginosa or Hemophilus influenzae. There was no statistically significant difference in use of high-frequency chest wall oscillation, pulmonary rehabilitation services, or suppressive macrolide treatment across the groups (P > 0.05). There is a disproportionately high percentage of non-Hispainc White patients compared to non-Hispanic Black patients and Hispanic or Latino patients in the BRR. However, we found an overall similarity of care of BRR patients, regardless of racial and ethnic group.

Real-world disparities and ethical considerations with access to CFTR modulator drugs: Mind the gap!

The third Sustainable Development Goal (SDG), to ensure healthy lives and promote well-being for all at all ages, has particular relevance and implementation challenges amongst people living with rare diseases such as cystic fibrosis (CF). Although the treatment and projected outcome of CF has significantly improved with the advent of CF transmembrane conductance regulator protein modulator (CFTRm) therapy, there remains significant global inequality with regards to access to these life-saving and life-altering drugs. Elexacaftor, tezacaftor, and ivacaftor (ETI) triple combination therapy, first licensed in the United States in 2019, has rapidly become the standard of care for children aged 6 years and older in most high-income countries for individuals with CFTR variants responsive to ETI. Negotiated agreements for access to ETI are currently in place in North America,Europe, Israel ,Australia and New Zealand. However, less priority has been given to negotiate agreements for access to CFTRm in low-middle income countries(LMIC) with significant CF populations such as Central and South America, India, the Middle East, and Southern Africa. These countries and individuals living with CF are therefore effectively being left behind, in direct conflict with the stated principle of the 2030 SDGs. In this review, we highlight the current global inequity in access to CFTRm drugs and its impact on widening disparities between high-income countries and LMIC in CF outcomes and survival. We further discuss the reasons for this inequity and explore the ethical- and human rights-based principles and dilemmas that clinicians, families, governments, and healthcare funders must consider when prioritizing fair and affordable access to expensive CFTRm drugs. Lastly, we propose possible solutions to overcoming the barriers to accessing affordable CFTRm drugs in LMIC and illustrate with examples how access to drug therapies for other conditions have been successfully negotiated in LMIC through innovative partnerships between governments and pharmaceutical industries.

Fundamental and translational research in Cystic Fibrosis - why we still need it

Clinical treatments for cystic fibrosis (CF) underwent significant changes in the last decade as therapies targeting the basic defect in the CFTR protein were approved. Significant scientific progress has also been made in several other areas that may lead in the future to novel therapeutic approaches that can help fight CF in all individuals living with this disease. Thus, focusing on fundamental research in the CF field has and will continue to be of great importance. This has been one of the aims of the European Cystic Fibrosis Society (ECFS), which has promoted the ECFS Basic Science Conference (BSC) every year since 2004. This special issue covers the topics featured and discussed at the 17^th ECFS BSC, held in Albufeira (Portugal) in March 2022, and highlights advances in understanding CFTR, in using personalized medicine, and in developing innovative strategies to identify breakthrough therapies. This introduction highlights the topics presented throughout this special issue, thereby underscoring the relevance of fundamental research in CF.