A Phase 3 Open-Label Study of Elexacaftor/Tezacaftor/Ivacaftor in Children 6 through 11 Years of Age with Cystic Fibrosis and at Least One F508del Allele

Effectiveness and safety of elexacaftor/tezacaftor/ivacaftor treatment in children aged 6-11 years with cystic fibrosis in a real-world setting

BACKGROUND

Elexacaftor-tezacaftor-ivacaftor (ETI) is a highly effective cystic fibrosis (CF) transmembrane conductance regulator (CFTR) modulating therapy for people with CF and at least one F508del variant. However, there is limited data about the safety and efficacy of this therapy in pediatric populations and in real-world settings. This study aimed at evaluating the effectiveness, tolerability, and safety of ETI in children with CF.

METHODS

This was a prospective observational study including all children aged 6-11 years who initiated ETI therapy between October 2022 and March 2023 at the Pediatric CF Center of Milan (Italy). Study outcomes included changes in sweat chloride concentration, FEV1, LCI2.5, body mass index (BMI), tolerance, and safety. Mean changes in study outcomes from baseline through 24 weeks were estimated using mixed-effects regression models.

RESULTS

The study included 34 children with CF (median age: 8.3 years). At Week 12, we observed an average decrease in LCI2.5 of 2.3 units (95% confidence interval [CI]: -3.1; -1.5). At Week 24, sweat chloride concentration decreased by 63 mEq/L (95% CI: -69; -58), FEV1 increased by 8.8 percentage point (95% CI: 3.7; 13.9) and BMI increased by 0.15 standard deviation scores (95% CI: 0.04; 0.25). Skin rashes appeared in 6 patients which spontaneously resolved within a few days. One month after treatment initiation, one patient experienced an elevation in liver function test results, which subsequently decreased during follow-up visits without necessitating discontinuation of therapy.

CONCLUSIONS

Our data indicate that ETI therapy is well tolerated by children with CF and is effective in improving signs of lung function abnormalities from early childhood.

Nutritional status in the era of highly effective CFTR modulators

Advances in cystic fibrosis (CF) diagnostics and therapeutics have led to improved health and longevity, including increased body weight and decreased malnutrition in people with CF. Highly effective CFTR modulator therapies (HEMT) are associated with increased weight through a variety of mechanisms, accelerating trends of overweight and obesity in the CF population. Higher body mass index (BMI) is associated with improved pulmonary function in CF, yet the incremental improvement at overweight and obese BMIs is not clear. Improvements in pulmonary health with increasing BMI are largely driven by increases in fat-free mass (FFM), and impact of HEMT on FFM is uncertain. While trends toward higher weight and BMI are generally seen as favorable in CF, the increased prevalence of overweight and obesity has raised concern for potential risk of traditional age- and obesity-related comorbidities. Such comorbidities, including impaired glucose tolerance, hypertension, cardiac disease, hyperlipidemia, fatty liver, colon cancer, and obstructive sleep apnea, may occur on top of pre-existing CF-related comorbidities. CF nutrition recommendations are evolving in the post-modulator era to more individualized approaches, in contrast to prior blanket high-fat, high-calorie prescriptions for all. Ultimately, it will be essential to redefine goals for optimal weight and nutritional status to allow for holistic health and aging in people with CF.

Impact of elexacaftor/tezacaftor/ivacaftor therapy on lung clearance index and magnetic resonance imaging in children with cystic fibrosis and one or two F508del alleles

BACKGROUND

We recently demonstrated that elexacaftor/tezacaftor/ivacaftor (ETI) improves the lung clearance index (LCI) and abnormalities in lung morphology detected by magnetic resonance imaging (MRI) in adolescent and adult patients with cystic fibrosis (CF). However, real-world data on the effect of ETI on these sensitive outcomes of lung structure and function in school-age children with CF have not been reported. The aim of this study was therefore to examine the effect of ETI on the LCI and the lung MRI score in children aged 6-11 years with CF and one or two F508del alleles.

METHODS

This prospective, observational, multicentre, post-approval study assessed the longitudinal LCI up to 12 months and the lung MRI score before and 3 months after initiation of ETI.

RESULTS

A total of 107 children with CF including 40 heterozygous for F508del and a minimal function mutation (F/MF) and 67 homozygous for F508del (F/F) were enrolled in this study. Treatment with ETI improved the median (interquartile range (IQR)) LCI in F/MF (-1.0 (-2.0- -0.1); p<0.01) and F/F children (-0.8 (-1.9- -0.2); p<0.001) from 3 months onwards. Further, ETI improved the median (IQR) MRI global score in F/MF (-4.0 (-9.0-0.0); p<0.01) and F/F children (-3.5 (-7.3- -0.8); p<0.001).

CONCLUSIONS

ETI improves early abnormalities in lung ventilation and morphology in school-age children with CF and at least one F508del allele in a real-world setting. Our results support early initiation of ETI to reduce or even prevent lung disease progression in school-age children with CF.

Cutaneous manifestations of cystic fibrosis

Cystic fibrosis (CF) is caused by a mutation in the Cystic fibrosis transmembrane conductance regulator (CFTR) gene, and features recurrent sinus and pulmonary infections, steatorrhea, and malnutrition. CF is associated with diverse cutaneous manifestations, including transient reactive papulotranslucent acrokeratoderma of the palms, nutrient deficiency dermatoses, and vasculitis. Rarely these are presenting symptoms of CF, prior to pulmonary or gastrointestinal sequelae. Cutaneous drug eruptions are also highly common in patients with CF (PwCF) given frequent antibiotic exposure. Finally, CFTR modulating therapy, which has revolutionized CF management, is associated with cutaneous side effects ranging from acute urticaria to toxic epidermal necrolysis. Recognition of dermatologic clinical manifestations of CF is important to appropriately care for PwCF. Dermatologists may play a significant role in the diagnosis and management of CF and associated skin complications.

New Therapies in Outpatient Pulmonary Medicine

Newer medications and devices, as well as greater understanding of the benefits and limitations of existing treatments, have led to expanded treatment options for patients with lung disease. Treatment advances have led to improved outcomes for patients with asthma, chronic obstructive pulmonary disease, interstitial lung disease, pulmonary hypertension, and cystic fibrosis. The risks and benefits of available treatments are substantially variable within these heterogeneous disease groups. Defining the role of newer therapies mandates both an understanding of these disorders and overall treatment approaches. This section will review general treatment approaches in addition to focusing on newer therapies for these conditions..

Gene expression responses of CF airway epithelial cells exposed to elexacaftor/tezacaftor/ivacaftor (ETI) suggest benefits beyond improved CFTR channel function

The combination of elexacaftor/tezacaftor/ivacaftor (ETI, Trikafta) reverses the primary defect in Cystic Fibrosis (CF) by improving CFTR mediated Cl - and HCO 3 - secretion by airway epithelial cells (AEC), leading to improved lung function and less frequent exacerbations and hospitalizations. However, studies have shown that CFTR modulators like ivacaftor, a component of ETI, has numerous effects on CF cells beyond improved CFTR channel function. Because little is known about the effect of ETI on CF AEC gene expression we exposed primary human AEC to ETI for 48 hours and interrogated the transcriptome by RNA-seq and qPCR. ETI increased defensin gene expression ( DEFB1 ) an observation consistent with reports of decreased bacterial burden in the lungs of people with CF (pwCF). ETI also decreased MMP10 and MMP12 gene expression, suggesting that ETI may reduce proteolytic induced lung destruction in CF. ETI also reduced the expression of the stress response gene heme oxygenase ( HMOX1 ). qPCR analysis confirmed DEFB1, HMOX1, MMP10 and MMP12 gene expression results observed by RNA-seq. Gene pathway analysis revealed that ETI decreased inflammatory signaling, cellular proliferation and MHC Class II antigen presentation. Collectively, these findings suggest that the clinical observation that ETI reduces lung infections in pwCF is related in part to drug induced increases in DEFB1 , and that ETI may reduce lung damage by reducing MMP10 and MMP12 gene expression, which is predicted to reduce matrix metalloprotease activity. Moreover, pathway analysis also identified several genes responsible for the ETI induced reduction in inflammation observed in people with CF.

New and Noteworthy

Gene expression responses by CF AEC exposed to ETI suggest that in addition to improving CFTR channel function, ETI is likely to increase resistance to bacterial infection by increasing levels of beta defensin 1 (hBD-1). ETI may also reduce lung damage by suppressing MMP10, and reduce airway inflammation by repressing proinflammatory cytokine secretion by AEC cells.

Evaluation of elexacaftor-tezacaftor-ivacaftor treatment in individuals with cystic fibrosis and CFTRN1303K in the USA: a prospective, multicentre, open-label, single-arm trial

BACKGROUND

CFTR modulators are approved for approximately 90% of people with cystic fibrosis in the USA and provide substantial clinical benefit. N1303K (Asn1303Lys), one of the most common class 2 CFTR defects, has not been approved for these therapies by any regulatory agency. Preclinical investigation by our laboratories showed N1303K CFTR activation with elexacaftor-tezacaftor-ivacaftor (ETI). In this trial, we evaluate whether ETI improves CFTR function, measured by sweat chloride and other clinical outcomes, in people with cystic fibrosis and CFTRN1303K.

METHODS

In this prospective, open-label, single-arm trial, participants aged 12 years or older with cystic fibrosis encoding at least one N1303K variant and at least one CFTRN1303K allele who were ineligible for modulator therapy by US Food and Drug Administration labelling were given ETI for 28 days followed by a 28-day washout period at two cystic fibrosis centres in the USA. Participants received two orally administered pills of 100 mg elexacaftor, 50 mg tezacaftor, and 75 mg ivacaftor once daily in the morning, and 150 mg ivacaftor once daily in the evening. The primary endpoint was mean change in sweat chloride from baseline up to day 28 compared with mixed-effects models. Secondary endpoints were changes in percentage of predicted FEV1 (ppFEV1), Cystic Fibrosis Questionnaire-Revised (CFQ-R) respiratory domain, BMI, and weight after ETI therapy. Safety was assessed in all participants who received at least one dose of the study drug and primary and secondary analyses were performed in all participants who took the study drug per protocol. The trial was registered at ClinicalTrials.gov (NCT03506061) and remains open for reporting purposes.

FINDINGS

Between June 7, 2022, and Oct 20, 2023, 20 participants (ten male and ten female) were enrolled and received ETI treatment. One participant was lost to follow-up but was included in intention-to-treat analyses. At 28 days, the mean sweat chloride reduction was -1·1 mmol/L (95% CI -5·3 to 3·1; p=0·61) with only one participant showing a sweat chloride decrease greater than 15 mmol/L. There was a mean increase in ppFEV1 from baseline at day 28 of 9·5 percentage points (6·7-12·3; p<0·0001) with 15 (75%) participants showing at least a 5% increase in ppFEV1. Improvements were also identified in mean CFQ-R respiratory domain score (20·8 increase [95% CI 11·9-29·8]; p<0·0001), BMI (0·4 kg/m2 increase [0·2-0·7]; p=0·0017), and weight (1·0 kg increase [0·4-1·7]; p=0·0020) after 28 days of ETI treatment. 14 (70%) of 20 participants had adverse events (12 [60%] mild, one [5%] moderate), with one (5%) serious adverse event of hospitalisation attributed to pneumonia. No deaths were recorded in the study.

INTERPRETATION

Individuals with CFTRN1303K showed no change in sweat chloride after 28 days of treatment with ETI. However, there were improvements in secondary clinical endpoints, which suggest clinical efficacy. Our approach provides support for the use of in vitro model systems to inform clinical trials for rare CFTR variants.

FUNDING

The Cystic Fibrosis Foundation and the US National Institutes of Health.

Extent of foetal exposure to maternal elexacaftor/tezacaftor/ivacaftor during pregnancy

BACKGROUND AND PURPOSE

Cystic fibrosis (CF) patients are living longer and healthier due to improved treatments, e.g. cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapy elexacaftor/tezacaftor/ivacaftor (ETI), with treatment possibly occurring in pregnancy. The risk of ETI to foetuses remain unknown. Thus the effect of maternally administered ETI on foetal genetic and structural development was investigated.

EXPERIMENTAL APPROACH

Pregnant Sprague Dawley rats were orally treated with ETI (6.7 mg·kg-1·day-1 elexacaftor + 3.5 mg·kg-1·day-1 tezacaftor + 25 mg·kg-1·day-1 ivacaftor) for 7 days from E12 to E19. Tissue samples collected at E19 were analysed using histology and RNA sequencing. Histological changes and differentially expressed genes (DEG) were assessed.

KEY RESULTS

No overt structural abnormalities were found in foetal pancreas, liver, lung and small intestine after 7-day ETI exposure. Very few non-functionally associated DEG in foetal liver, lung and small intestine were identified using RNA-seq. 29 DEG were identified in thymus (27 up-regulated and two down-regulated) and most were functionally linked to each other. Gene ontology enrichment analysis revealed that multiple muscle-related terms were significantly enriched. Many more DEG were identified in cortex (44 up-regulated and four down-regulated) and a group of these were involved in central nervous system and brain development.

CONCLUSION AND IMPLICATION

Sub-chronic ETI treatment in late pregnancy does not appear to pose a significant risk to the genetic and structural development of many foetal tissues. However, significant gene changes in foetal thymic myoid cells and cortical neuronal development requires future follow-up studies to assess the risk to these organs.

Breastfeeding, growth, and lung disease in the first 3 years of life in children with cystic fibrosis

BACKGROUND

The 2009 cystic fibrosis (CF) infant care guidelines recommend breastmilk as the initial feeding but do not address if/when it should be fortified or supplemented with formula to promote optimal growth and pulmonary health.

METHODS

We conducted a prospective multi-center cohort study in breastfed and formula-fed infants that included 172 infants with CF who were born during 2012-17, enrolled after newborn screening at age 1.9 ± 1.0 months, and evaluated growth and lung disease manifestations in the first 3 years of life.

RESULTS

Seventy-two percent of our study cohort was breastfed at birth, but 64 % transitioned to receiving fortified feedings (breastmilk, formula, or a combination) by 6 months of age to reverse the downward trajectory of their growth curves. Fortified feedings accelerated catch-up growth to normal weight-for-age (0.12 ± 0.80 z-score) and near normal height-for-age (-0.13 ± 0.90 z-score) at 3 years of age. Within the fortified group, breastmilk and formula were similarly effective in promoting catch-up growth, but proportionately fewer infants with CF fed predominantly breastmilk (30 %) experienced severe or moderate early-onset lung disease compared to those fed predominantly formula (62 %), p = 0.02.

CONCLUSIONS

Most infants with CF require fortified feedings to recuperate from growth faltering and achieve normal growth at 3 years of age. For these infants, the proactive/preventive strategy of fortified breastmilk feedings starting soon after CF diagnosis, an alternative to the reactive/monitoring approach, can minimize the risk of prolonged postnatal growth faltering, accelerate the potential of attaining catch-up growth, and decrease the likelihood of experiencing more severe early-onset lung disease.

[Adverse effects of the tezacaftor/ivacaftor/elexacaftor combination that may lead to discontinuation: About a series of 10 cases]

INTRODUCTION

Cystic fibrosis transmembrane regulator (CFTR) channel modulators (ivacaftor, lumacaftor, tezacaftor and elexacaftor) represent a major advance in the management of cystic fibrosis. However, few data are available on the real-life safety profile of these medications, in particular on adverse events that may lead to their discontinuation. The aim of this study is to describe the characteristics and evolution of adverse reactions to the tezacaftor/ivacaftor/elexacaftor combination that led to discontinuation and were reported to the Centre régional de pharmacovigilance (CRPV) in Rennes (France).

MATERIALS AND METHODS

A retrospective study was conducted from December 2021 to May 2023, focusing on cases of discontinuation of the tezacaftor/ivacaftor/elexacaftor combination due to the occurrence of one or more adverse effects, and reported to the CRPV of Rennes, France.

RESULTS

Ten cases of drug discontinuation were reported to the Rennes CRPV (6 women/4 men). Adverse effects mainly involved neuropsychiatric disorders (n=6), followed by liver disorders (n=2), ear, nose and throat disorders (n=1), and digestive disorders (n=1). The average duration of treatment at discontinuation was 339.8 [39-668] days. The drug was reintroduced in 7 patients on average 48.7 [7-123] days after discontinuation, with a dosage adjustments (n=4) consisting of changes in dosing times or a reduction in daily doses, with varying success in alleviating adverse symptoms depending on the case.

CONCLUSION

This small case series suggests that neuropsychiatric adverse effects may occur more frequently than initially described after initiation of tezacaftor/ivacaftor/elexacaftor, and should be carefully screened and monitored. Dosage or administration schedule modifications may be considered for patients experiencing these adverse effects. Further pharmacovigilance studies are needed to better understand the adverse effect profiles of "caftors", their possible risk factors, and the impact of adjusting dosing modalities.

Clinical efficacy of CFTR modulator therapy in people with cystic fibrosis carrying the I1234V mutation

BACKGROUND

The cystic fibrosis transmembrane conductance regulator (CFTR) mutation I1234V (I1234V, p.Ile1234Val, c.3700A>G), is a missense-mutation that creates a cryptic splice site, with the formation of a protein lacking 6 amino acids, that is misfolded and misprocessed. The in vitro effects of CFTR modulator (CFTRm) therapies on human bronchial cell models and intestinal organoids carrying this mutation are conflicting. The aim of this study was therefore to explore the clinical efficacy of CFTRm in people with cystic fibrosis (pwCF) carrying this mutation.

METHODS

This was a retrospective descriptive study of the clinical records of homozygous and compound heterozygous (none F508del) pwCF, for the I1234V mutation, that received CFTRm. Parameters explored were body mass index (BMI), forced expiratory volume in one second percent predicted (FEV1%), lung clearance index (LCI) and quantitative sweat chloride measurements.

RESULTS

Mean age was 38.6 ± 14 years (range 21-60). Two subjects were homozygous and five compound heterozygous, with minimal function mutations. Four were pancreatic insufficient and three pancreatic sufficient. The two homozygous subjects received Tezacaftor/Ivacaftor, the remaining Elexacaftor/Tezacaftor/Ivacaftor (ETI); treatment ranged from 6 to 12 months. Mean BMI score increased from 21.7 ± 1.3 to 23.6 ± 2.1 kg/m2 (p = 0.04); FEV1(%pred) increased by 20.14±10.2while mean change in FEV1 in the year prior to CFTRm initiation was -0.14±1.18 (p = 0.0001). Additionally, LCI 2.5% decreased from 18.7 to 14.5 (p = 0.07); sweat chloride decreased from 116±10 to 90±17 mEq/L (p = 0.017) and chronic pseudomonas airway infection was eradicated in one subject.

CONCLUSIONS

This study supports a clinical benefit for CFTRm therapy in pwCF carrying the I1234V mutation.

Reported Adverse Events in a Multicenter Cohort of Patients Ages 6-18 Years with Cystic Fibrosis and at Least One F508del Allele Receiving Elexacaftor/Tezacaftor/Ivacaftor

OBJECTIVE

The objective of this study was to describe reported adverse events (AEs) associated with elexacaftor/tezacaftor/ivacaftor (ETI) in a pediatric sample with cystic fibrosis (CF) aged 6-18 years, with at least one F508del variant, followed at multiple Italian CF centers.

STUDY DESIGN

This was a retrospective, multicenter, observational study. All children receiving ETI therapy from October 2019 to December 2023 were included. We assessed the prevalence and type of any reported potential drug-related AEs, regardless of discontinuation necessity. Persistent AEs were defined as those continuing at the end of the observation period.

RESULTS

Among 608 patients on ETI, 109 (17.9%) reported at least 1 AE. The majority (n = 85, 77.9%) were temporary, with a median duration of 11 days (range 1-441 days). Only 7 (1.1%) patients permanently discontinued treatment, suggesting good overall safety of ETI. The most common AEs leading to discontinuation were transaminase elevations (temporary 14.1%, persistent 25.9%) and urticaria (temporary 41.2%, persistent 7.4%). Creatinine phosphokinase elevation was uncommon. No significant differences in AEs were observed based on sex, age groups (6-11 vs 12-18 years), or genotype. Pre-existing CF-related liver disease was associated with an increased risk of transaminase elevations. We identified significant variability in the percentage of reported AEs (ANOVA P value .026).

CONCLUSIONS

This real-world study highlights significant variability in reported AEs. Our findings suggest that ETI is a safe and well-tolerated therapy in children and adolescents with CF. However, further long-term safety and effectiveness investigations are warranted.

Cystic fibrosis liver disease in the new era of cystic fibrosis transmembrane conductance regulator (CFTR) modulators

Cystic fibrosis liver disease (CFLD) is characterised by a wide heterogenity of manifestations and severity. It represents a major cause of morbidity in people with cystic fibrosis (PwCF), which will be of increasing relevance as survival increases in the new era of cystic fibrosis care. No medical therapy currently available has evidence to treat or prevent progression of liver disease. Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) modulators may be transformative on pulmonary, nutritional and quality of life, but direct effect on long term liver disease outcomes is not yet established. Drug-associated hepatic adverse effects may be common, and clinician familiarity with drug-monitoring recommendations is essential. Longitudinal studies are required to understand the effect of CFTR modulators on the incidence and natural history of CFLD, including with early treatment initiation, in established advanced liver disease, and post liver transplantation.

Pharmacological Improvement of Cystic Fibrosis Transmembrane Conductance Regulator Function Rescues Airway Epithelial Homeostasis and Host Defense in Children with Cystic Fibrosis

Rationale: Pharmacological improvement of cystic fibrosis transmembrane conductance regulator (CFTR) function with elexacaftor/tezacaftor/ivacaftor (ETI) provides unprecedented improvements in lung function and other clinical outcomes in patients with cystic fibrosis (CF). However, ETI effects on impaired mucosal homeostasis and host defense at the molecular and cellular levels in the airways of patients with CF remain unknown. Objectives: To investigate effects of ETI on the transcriptome of nasal epithelial and immune cells from children with CF at the single-cell level. Methods: Nasal swabs from 13 children with CF and at least one F508del allele aged 6 to 11 years were collected at baseline and 3 months after initiation of ETI, subjected to single-cell RNA sequencing, and compared with swabs from 12 age-matched healthy children. Measurements and Main Results: Proportions of CFTR-positive cells were decreased in epithelial basal, club, and goblet cells, but not in ionocytes, from children with CF at baseline and were restored by ETI therapy to nearly healthy levels. Single-cell transcriptomics revealed an impaired IFN signaling and reduced expression of major histocompatibility complex classes I and II encoding genes in epithelial cells of children with CF at baseline, which was partially restored by ETI. In addition, ETI therapy markedly reduced the inflammatory phenotype of immune cells, particularly of neutrophils and macrophages. Conclusions: Pharmacological improvement of CFTR function improves innate mucosal immunity and reduces immune cell inflammatory responses in the upper airways of children with CF at the single-cell level, highlighting the potential to restore epithelial homeostasis and host defense in CF airways by early initiation of ETI therapy.

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.

Drug-induced liver injury associated with elexacaftor/tezacaftor/ivacaftor: A pharmacovigilance analysis of the FDA adverse event reporting system (FAERS)

INTRODUCTION

The efficacy and safety of elexacaftor/tezacaftor/ivacaftor (ETI) have been established in prospective clinical trials. Liver function test elevations were observed in a greater proportion of patients receiving ETI compared with placebo; however, the relatively small number of patients and short duration of study preclude detection of rare but clinically significant associations with drug-induced liver injury (DILI). To address this gap, we assessed the real-world risk of DILI associated with ETI through data mining of the FDA adverse event reporting system (FAERS).

METHODS

Disproportionality analyses were conducted on FAERS data from the fourth quarter of 2019 through the third quarter of 2022. Comparative patient demographics, onset time and outcomes for ETI-DILI were also obtained.

RESULTS

452 reports of DILI associated with ETI were found, representing 2.1 % of all adverse event reports for ETI. All disproportionality measures were significant for ETI-DILI at p < 0.05; the reporting odds ratio (ROR) (2.82) was comparable to that of drugs classified by FDA as "Most-DILI concern". The most notable demographic finding was a male majority (5:4 male to female ratio) for ETI-DILI compared to a female majority (4:5 male to female ratio) for non ETI-DILI. Median ETI-DILI onset time was 50.5 days, and hospitalization was the second most common complication.

CONCLUSION

Using FAERS data, ETI was found to be disproportionately associated with DILI. Future research is needed to investigate the hepatotoxic mechanisms and assess potential mitigation strategies for ETI-induced hepatotoxicity.

Reduction in abdominal symptoms (CFAbd-Score), faecal M2-pyruvate-kinase and Calprotectin over one year of treatment with Elexacaftor-Tezacaftor-Ivacaftor in people with CF aged ≥12 years - The RECOVER study

BACKGROUND

RECOVER is a multicentre post-approval study of Elexacaftor/Tezacaftor/Ivacaftor (ETI) in pwCF in Ireland and the UK. The CFAbd-Score is the first validated CF-specific patient reported outcome measure (PROM) focusing on gastrointestinal symptoms; it comprises 28 items in 5 domains. In a preliminary study, we previously reported reductions in abdominal symptoms (AS) in pwCF after 26 weeks of ETI-therapy using the CFAbd-Score.

AIM

to assess changes in AS in a second, large cohort and explore novel GI-biomarkers of gut inflammation and cell-proliferation in pwCF over one year of ETI-therapy.

METHODS

Participants were recruited as part of the RECOVER study at 8 sites (Ireland&UK). The CFAbd-Score was administered prior to ETI-initiation, and subsequently at 1,2,6 and 12 months on treatment. Faecal M2-pyruvate kinase (M2-PK) and calprotectin (FC) were quantified in samples collected at baseline, 1 and 6 months.

RESULTS

108 CFAbd-Scores and 73 stool samples were collected at baseline. After 12 months of ETI-therapy, total CFAbd-Scores had significantly declined (15.0±1.4→9.8±1.2pts/p<0.001), and so had all its five domains of "pain" (16.9±2.0pts→9.9±1.8pts/p<0.01), "GERD" (14.4±1.8→9.9±1.6/p<0.05), "disorders of bowel movements" (19.2±1.4→14.1±1.5/p<0.01), "appetite" (7.0±1.1→4.6±1.2/p<0.01) and "impaired-QoL" (13.3±1.9→7.5±1.5/p<0.001). Levels of M2-PK and FC significantly decreased during ETI-therapy.

DISCUSSION

In-depth analysis of AS with the CFAbd-Score reveals a statistically significant, clinically relevant and sustained improvement with ETI. We attribute this to high sensitivity of the implemented CF-specific PROM, developed and validated following FDA-guidelines. Furthermore, for the first time during ETI-therapy a significant decline in faecal M2-PK, a marker of inflammation and cell-proliferation, was found, in parallel to FC.

Lung clearance index (LCI2.5) changes after initiation of Elexacaftor/Tezacaftor/Ivacaftor in children with cystic fibrosis aged between 6 and 11 years: The "real-world" differs from trial data

BACKGROUND

Elexacaftor in combination with Tezacaftor and Ivacaftor (ETI) became licensed in the United Kingdom in early 2022 for children aged 6-11 years with cystic fibrosis (CF) and an eligible mutation. Many in this age group have excellent prior lung health making quantitative measurement of benefit challenging. Clinical trials purport that lung clearance index (LCI2.5) measurement is most suitable for this purpose.

OBJECTIVES

This study aimed to understand the clinical utility of LCI2.5 in detecting change after commencing ETI in the real world.

PATIENT SELECTION/METHODS

Baseline anthropometric data were collected along with spirometry (forced expiratory volume in 1 s [FEV1], forced vital capacityFV and LCI2.5 measures in children aged 6-11 years with CF before starting ETI. Measures were repeated after a mean (range) of 8.2 (7-14) months of ETI treatment. The primary endpoint was a change in LCI2.5, with secondary endpoints including change in FEV1 and change in body mass index (BMI) also reported.

RESULTS

Twelve children were studied (seven male, mean age 9.5 years at baseline). Our study population had a mean (SD) LCI2.5 of 7.01 (1.14) and FEV1 of 96 (13) %predicted at baseline. Mean (95% confidence interval) changes in LCI2.5 [-0.7 (-1.4, 0), p = .06] and BMI [+0.7 (+0.1, +1.3), p = .03] were observed, along with changes in FEV1 of +3.1 (-1.9, +8.1) %predicted.

CONCLUSIONS

Real-world changes in LCI2.5 (-0.7) are different to those reported in clinical trials (-2.29). Lower baseline LCI2.5 as a result of prior modulator exposure, high baseline lung health, and new LCI2.5 software analyses all contribute to lower LCI2.5 values being recorded in the real world of children with CF.

Real-world effectiveness of elexacaftor/tezacaftor/ivacaftor on the burden of illness in adolescents and adults with cystic fibrosis

Background

Elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) has been shown to be safe and efficacious in people with cystic fibrosis (CF) aged ≥2 years. Here, we describe results from an observational study assessing change in burden of illness following initiating ELX/TEZ/IVA in real-world settings.

Methods

This US-based, multicenter, observational study used data from electronic medical records to evaluate real-world burden of illness before and after ELX/TEZ/IVA initiation in people with CF aged ≥12 years heterozygous for F508del and a minimal function mutation (F/MF) or an uncharacterized CFTR mutation. Endpoints included absolute change from baseline in percent predicted forced expiratory volume in 1 s (ppFEV1), body mass index (BMI) and BMI-for-age z-score, glycated hemoglobin (HbA1c), and numbers of pulmonary exacerbations (PEx).

Results

Overall, 206 people with CF were enrolled (mean [SD] age 22.5 [11.1] years; 192 [93.2%] with F/MF genotype). Mean follow-up was 15.6 (SD, 1.6) months. Improvements in ppFEV1 (7.3 [95% CI: 5.7, 8.8] percentage points) were observed from baseline through follow-up. Increases in BMI (1.40 [95% CI: 1.07, 1.77] kg/m2) and BMI-for-age z-score (0.14 [95% CI: 0.00, 0.28]) were also observed from baseline at 12 months. The estimated annualized rate of any PEx was 1.31 at baseline and 0.61 over follow-up (rate ratio 0.47 [95% CI: 0.39, 0.55]), with annualized rates of PEx requiring antibiotics and hospitalizations of 0.55 and 0.88 in the baseline period and 0.12 and 0.36 over follow-up (rate ratios 0.22 [95% CI: 0.15, 0.31] and 0.41 [95% CI: 0.32, 0.51]), respectively. Absolute change in HbA1c was -0.22 (95% CI: -0.38, -0.06) from baseline through follow-up.

Conclusions

ELX/TEZ/IVA treatment was associated with improved lung function, increased BMI, reduced frequency of PEx, and improved (i.e., reduced) HbA1c. These results confirm the broad clinical benefits of ELX/TEZ/IVA seen in clinical trials and show the potential for ELX/TEZ/IVA to improve markers of glucose metabolism.

Recommended Tool Compounds for Modifying the Cystic Fibrosis Transmembrane Conductance Regulator Channel Variants

Cystic fibrosis (CF) is a genetic disorder arising from variations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, leading to multiple organ system defects. CFTR tool compounds are molecules that can modify the activity of the CFTR channel. Especially, patients that are currently not able to benefit from approved CFTR modulators, such as patients with rare CFTR variants, benefit from further research in discovering novel tools to modulate CFTR. This Review explores the development and classification of CFTR tool compounds, including CFTR blockers (CFTRinh-172, GlyH-101), potentiators (VRT-532, Genistein), correctors (VRT-325, Corr-4a), and other approved and unapproved modulators, with detailed descriptions and discussions for each compound. The challenges and future directions in targeting rare variants and optimizing drug delivery, and the potential synergistic effects in combination therapies are outlined. CFTR modulation holds promise not only for CF treatment but also for generating CF models that contribute to CF research and potentially treating other diseases such as secretory diarrhea. Therefore, continued research on CFTR tool compounds is critical.

Elexacaftor/Tezacaftor/Ivacaftor use in Pediatric Cystic Fibrosis Patients with Advanced Liver Disease

BACKGROUND

Cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapy extends the life expectancy of people with cystic fibrosis (PwCF). However, CFTR modulators have not been well studied in patients with cystic fibrosis liver disease (CFLD), specifically those with advanced liver disease with portal hypertension. The purpose of this report is to describe the use of elexacaftor/tezacaftor/ivacaftor (ETI) in pediatric CF patients with advanced CFLD.

METHODS

This retrospective case series included PwCF < 18 years old with baseline advanced CFLD initiated on ETI.

RESULTS

Eleven PwCF and advanced CFLD were treated with ETI; six started a reduced dose regimen. No patient required treatment interruption and four patients received dose changes related to increase in transaminase and/or bilirubin elevations. Mean (SD) change in ppFEV1 from prior to ETI to highest value during therapy was 14.27 % (4.25) (p = 0.007). When evaluating the group as whole, AST decreased from baseline to last reported -15.18 (23.23) units/L (p = 0.054) and ALT slightly increased 0.73 (39.13) units/L (p = 0.96). Bilirubin increased minimally overall for patients with mean change from baseline of 0.83 (1.33) mg/dL [range -0.5-3] (p = 0.17). A model for time on ETI showed a significant decrease in AST over time of 0.955 per month of ETI but no other liver biochemistries were significant. No patient experienced decompensation of CFLD.

CONCLUSION

ETI therapy in pediatric CF patients with advanced CFLD can be beneficial in improving pulmonary and nutritional outcomes without negative impact on liver biochemistries or hepatic outcomes. Close monitoring is recommended to ensure safety and tolerability.

Diagnosing Cystic Fibrosis in the 21st Century-A Complex and Challenging Task

Cystic fibrosis (CF) is a chronic and potentially life-threatening condition, wherein timely diagnosis assumes paramount significance for the prompt initiation of therapeutic interventions, thereby ameliorating pulmonary function, addressing nutritional deficits, averting complications, mitigating morbidity, and ultimately enhancing the quality of life and extending longevity. This review aims to amalgamate existing knowledge to provide a comprehensive appraisal of contemporary diagnostic modalities pertinent to CF in the 21st century. Deliberations encompass discrete delineations of each diagnostic modality and the elucidation of potential diagnostic quandaries encountered in select instances, as well as the delineation of genotype-phenotype correlations germane to genetic counseling endeavors. The synthesis underscores that, notwithstanding the availability and strides in diagnostic methodologies, including genetic assays, the sweat test (ST) retains its position as the preeminent diagnostic standard for CF, serving as a robust surrogate for CFTR functionality. Prospective clinical investigations in the realm of CF should be orchestrated with the objective of discerning novel diagnostic modalities endowed with heightened specificity and sensitivity.

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.

Lumacaftor/Ivacaftor Population Pharmacokinetics in Pediatric Patients with Cystic Fibrosis: A First Step Toward Personalized Therapy

BACKGROUND

A major breakthrough in cystic fibrosis (CF) therapy was achievedAQ1 with CFTR modulators. The lumacaftor/ivacaftor combination is indicated for the treatment of CF in pediatric patients above 6 years old. Pharmacokinetic (PK) studies of lumacaftor/ivacaftor in these vulnerable pediatric populations are AQ2crucial to optimize treatment protocols.

OBJECTIVES AND METHODS

The objectives of this study were to describe the population PK (PPK) of lumacaftor and ivacaftor in children with CF, and to identify factors associated with interindividual variability. The association between drug exposure and clinical response was also investigated.

RESULTS

A total of 75 children were included in this PPK study, with 191 concentrations available for each compound and known metabolites (lumacaftor, ivacaftor, ivacaftor-M1, and ivacaftor-M6). PPK analysis was performed using Monolix software. A large interindividual variability was observed. The main sources of interpatient variability identified were patient bodyweight and hepatic function (aspartate aminotransferase). Forced expiratory volume in the first second (FEV1) was statistically associated with the level of exposure to ivacaftor after 48 weeks of treatment.

CONCLUSIONS

This study is the first analysis of lumacaftor/ivacaftor PPK in children with CF. These data suggest that dose adjustment is required after identifying variability factors to optimize efficacy. The use of therapeutic drug monitoring as a basis for dose adjustment in children with CF may be useful.

A grumbling concern: A survey of gastrointestinal symptoms in cystic fibrosis in the modulator era

Background

Gastrointestinal symptoms in cystic fibrosis (CF) are common and intrusive to daily life. Relieving gastrointestinal symptoms was identified as an important research priority and previously explored in an international survey in 2018. However, following the widespread introduction of cystic fibrosis transmembrane conductance regulator (CFTR) modulators in 2019, the landscape of CF treatment has changed. We repeated an online survey to further describe gastrointestinal symptoms and their effect on quality of life (QoL) in the CFTR modulator era.

Methods

An electronic survey consisting of closed questions and free text responses was distributed via social media and professional networks for a period of one month between March - April 2022. People with CF (pwCF), their family and friends, and healthcare professionals (HCPs) were invited to take part.

Results

There were 164 respondents: 88 pwCF (54%), 22 (13%) family, and 54 (33%) healthcare professionals (HCPs). A total of 89/110 (81%) pwCF or family members reported CFTR modulator treatment. The most commonly reported symptoms were wind / gas and rumbling stomach noises (borborygmi) in both the modulator and non-modulator groups in addition to loose motions (modulator group) and bloating (no modulator group). Abdominal pain and bloating had the greatest impact on QoL.For those on a CFTR modulator, the proportion of pwCF reporting "no change" or "worse" for all of the symptoms surveyed was greater than the proportion reporting an improvement. For some symptoms such as stomach pains and reduced appetite, improvements were perceived more commonly in HCPs than what was reported by pwCF. Following modulator introduction, dietary changes to manage GI symptoms were recommended by 28/35 (80%) of HCPs and reported by 38/76 (50%) lay respondents. Changes in medication were recommended by 19/35 (54%) HCPs and reported by 44/76 (58%) of patients and family members.

Conclusion

This survey has shown that gastrointestinal symptoms remain prevalent in pwCF in the CFTR modulator era, though the nature of these symptoms may have changed. A better understanding of the underlying pathophysiology of these symptoms is essential. Future clinical studies should focus on improving symptoms and QoL.

Elexacaftor/Tezacaftor/Ivacaftor Treatment and Depression-related Events

Rationale: Elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) has been shown to be safe and efficacious in people with cystic fibrosis (pwCF) aged 2 years and older with at least one F508del-CFTR allele or more. After U.S. approval in 2019, reports emerged of depression-related adverse events in pwCF treated with ELX/TEZ/IVA. Objectives: To review available evidence on depression-related events in pwCF treated with ELX/TEZ/IVA in the context of background epidemiology in pwCF. Methods: Safety data from 14 ELX/TEZ/IVA clinical trials and 10 trials of CF transmembrane conductance regulator (CFTR) modulators in which placebo was administered, along with data from CF registries in the United States and Germany and cumulative postmarketing adverse event data from 61,499 pwCF who initiated ELX/TEZ/IVA after initial approval in the United States (October 2019) through October 2022, were reviewed and used to calculate exposure-adjusted rates of depression-related adverse events and prevalence of depression. In addition, a scientific literature review was conducted to identify ELX/TEZ/IVA publications reporting depression-related events or changes in depressive symptoms after treatment initiation. Measurements and Main Results: In clinical trials, the exposure-adjusted rate of any depression-related adverse event was 3.32/100 person years (PY) in the pooled ELX/TEZ/IVA group (n = 1,711) and 3.24/100 PY in the pooled placebo group (n = 1,369). The exposure-adjusted rates of suicidal ideation and suicide attempt were also similar between the pooled ELX/TEZ/IVA group and pooled placebo group (ideation: 0.23/100 PY vs. 0.28/100 PY; attempt: 0.08/100 PY vs. 0.14/100 PY). In the postmarketing setting, the exposure-adjusted reporting rates of depression-related events were low in context of the background prevalence in pwCF (all depression-related events: 1.29/PY; suicidal ideation: 0.12/100 PY; and suicide attempt: 0.05/100 PY). Assessments of individual case reports were confounded by preexisting mental health conditions, intercurrent psychosocial stressors (including coronavirus disease [COVID-19] lockdowns), and the heterogeneous and fluctuating nature of depression. Data from CF registries in the United States and Germany showed that patterns of depression prevalence in pwCF exposed to ELX/TEZ/IVA did not change after treatment initiation. Published studies utilizing the nine-item Patient Health Questionnaire did not show evidence of worsening depression symptoms in pwCF treated with ELX/TEZ/IVA. Conclusions: Our review of data from clinical trials, postmarketing reports, an ongoing registry-based ELX/TEZ/IVA postauthorization safety study, and peer-reviewed literature suggests that depression symptoms and depression-related events reported in pwCF treated with ELX/TEZ/IVA are generally consistent with background epidemiology of these events in the CF population and do not suggest a causal relationship with ELX/TEZ/IVA treatment.

Elexacaftor-tezacaftor-ivacaftor for cystic fibrosis with Phe508del mutation: Evidence from randomized controlled trials

Objective

This study aimed to conduct a systematic review and meta-analysis of randomized controlled trials to evaluate the effects of elexacaftor-tezacaftor-ivacaftor (ELX-TEZ-IVA) on patients with cystic fibrosis (CF).

Methods

A systematic search was performed in PubMed, Embase, and the Cochrane Library from inception to August 1, 2022. Meta-analysis was conducted using Review Manager 5.3 software.

Results

Six studies comprising seven reports involving a total of 1125 CF patients were included. The meta-analyses indicated that ELX-TEZ-IVA significantly improved the percentage predicted forced expiratory volume in 1 s (ppFEV1) by 10.29% (95% confidence interval (CI) (6.44, 14.14), p < 0.00001) and the CF questionnaire-revised respiratory domain (CFQ-R RD) by 14.59 points (95% CI (9.25, 19.94), p < 0.00001) compared to placebo, ivacaftor (IVA), or tezacaftor-ivacaftor (TEZ-IVA). In addition, the ELX-TEZ-IVA group showed significantly lower sweat chloride concentrations by 40.30 mmol/L (95% CI (-49.85, -30.74), p < 0.00001). However, the incidence of adverse events in the ELX-TEZ-IVA group was slightly higher than that in the placebo, IVA, or TEZ-IVA groups.

Conclusion

ELX-TEZ-IVA demonstrated efficacy in improving ppFEV1, CFQ-R RD, and sweat chloride concentrations in patients with CF. However, caution should be exercised regarding the incidence of AEs, particularly mild and moderate ones.

Raman Spectroscopy and Cystic Fibrosis Disease: An Alternative Potential Tool for Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Modulator Response Differentiation-A Pilot Study Based on Serum Samples

Cystic fibrosis (CF) is a genetic disorder that alters chloride transport in mucous membranes. Recent studies have demonstrated that treatment with modulators of the chloride channel reduces inflammatory markers, restoring, among others, the imbalance of lipids. In this study, we analyzed the serum samples of treated and non-treated patients with modulators with Raman spectroscopy. Nineteen (eight treated an eleven non-treated) patients were considered. The main difference between the two groups appeared in the 3020-2800 cm-1 range. A Voigt deconvolution fit was performed, and nine sub-bands were identified. To distinguish between treated and non-treated patients, the area ratio between the CH3 and CH2 vibration modes was calculated for each patient. The results were validated using statistical analyses. In particular, receiver operating characteristic (ROC) curves and Youden index (Y) were calculated (Area Under Curve (AUC): 0.977; Y: 3.30). An ROC curve represents the performance of the classification, illustrating the diagnostic ability of Raman spectroscopy. It was demonstrated that Raman spectroscopy is able to highlight peculiar differences between elexacaftor/tezacaftor/ivacaftor (ETI)-treated and non-treated patients, in relation with lipids biomarkers.

Comparison of particles in exhaled air and multiple breath washout for assessment of small airway function in children with cystic fibrosis

BACKGROUND

The introduction of modulator therapy for cystic fibrosis (CF) has led to an increased interest in the detection of small airway disease (SAD) as sensitive marker of treatment response. The particles in exhaled air (PExA) method, which records exhaled particle mass (PEx ng/L) and number (PExNR), detects SAD in adult patients. Our primary aim was to investigate if PExA outcomes in children with CF are different when compared to controls and associated with more severe disease. Secondary aims were to assess feasibility and repeatability of PExA in children with CF and to correlate PExA to multiple breath nitrogen washout (MBNW) as an established marker of SAD.

METHODS

Thirteen healthy children (HC), 17 children with CF with normal lung function (CF-N) (FEV1 z-score ≥ -1.64) and six with airway obstruction (CF-AO) (FEV1 z-score < -1.64) between 8 and 18 years performed MBNW followed by PExA and spirometry. Children with CF repeated the measurements after 3 months.

RESULTS

PEx ng/L and PExNR/L per liter of exhaled breath were similar between the three groups. The lung clearance index (LCI) was significantly higher in both CF-N and CF-AO compared to HC. All participants, except one, were able to perform PExA. Coefficient of variation for PEx ng/l was (median) 0.38, range 0-1.25 and PExNR/l 0.38, 0-1.09. Correlation between LCI and PEx ng/l was low, rs 0.32 (p = .07).

CONCLUSION

PExA is feasible in children. In contrast to LCI, PExA did not differentiate healthy children from children with CF suggesting it to be a less sensitive tool to detect SAD.

Cystic fibrosis airway inflammation enables elexacaftor/tezacaftor/ivacaftor-mediated rescue of N1303K CFTR mutation

Rescue of N1303K CFTR by highly effective modulator therapy (HEMT) is enabled by CF airway inflammation. These findings suggest that evaluation of HEMT for rare CFTR mutations must be performed under inflammatory conditions relevant to CF airways. https://bit.ly/3tTcoJE.

Efficacy and safety profile of elexacaftor-tezacaftor-ivacaftor triple therapy on cystic fibrosis: a systematic review and single arm meta-analysis

Background: Elexacaftor-Tezacaftor-Ivacaftor (ELE/TEZ/IVA) is believed to be an effective and well-tolerated treatment for cystic fibrosis (CF), but the exact efficacy and safety profile are still unknown. Objective: This study aimed to clarify the extent of functional restoration when patients are given with triple combination treatment and demonstrate the prevalence of adverse events, to evaluate the overall profile of ELE/TEZ/IVA on CF. Methods: A literature search was conducted in PubMed, Web of Science and Cochrane Library. Random effects single-arm meta-analysis was performed to decipher the basal characteristics of CF, the improvement and safety profile after ELE/TEZ/IVA treatment. Results: A total 53 studies were included in this analysis. For all the patients in included studies. 4 weeks after ELE/TEZ/IVA treatment, the increasement of percentage of predicted Forced Expiratory Volume in the first second (ppFEV1) was 9.23% (95%CI, 7.77%-10.70%), the change of percentage of predicted Forced Vital Capacity (ppFVC) was 7.67% (95%CI, 2.15%-13.20%), and the absolute change of Cystic Fibrosis Questionnaire-Revised (CFQ-R) score was 21.46 points (95%CI, 18.26-24.67 points). The Sweat chloride (SwCl) was significantly decreased with the absolute change of -41.82 mmol/L (95%CI, -44.38 to -39.25 mmol/L). 24 weeks after treatment, the increasement of ppFEV1 was 12.57% (95%CI, 11.24%-13.90%), the increasement of ppFVC was 10.44% (95%CI, 7.26%-13.63%), and the absolute change of CFQ-R score was 19.29 points (95%CI, 17.19-21.39 points). The SwCl was significantly decreased with the absolute change of -51.53 mmol/L (95%CI, -56.12 to -46.94 mmol/L). The lung clearance index2.5 (LCI2.5) was also decreased by 1.74 units (95%CI, -2.42 to -1.07 units). The body mass index increased by 1.23 kg/m2 (95%CI, 0.89-1.57 kg/m2). As for adverse events, 0.824 (95%CI, 0.769-0.879) occurred during ELE/TEZ/IVA period, while the incidence of severe adverse events was 0.066 (95%CI, 0.028-0.104). Conclusion: ELE/TEZ/IVA is a highly effective strategy and relatively safe for CF patients and needs to be sustained to achieve better efficacy. Systematic Review Registration: Identifier: CRD42023441840.

The impact of elexacaftor/tezacaftor/ivacaftor therapy on the pulmonary management of adults with cystic fibrosis: An expert-based Delphi consensus

BACKGROUND

The advent of elexacaftor/tezacaftor/ivacaftor (ETI) resulted in unprecedented clinical benefits for eligible adults with CF. As a result, the question of whether chronic treatments can be safely stopped or adapted to this new situation has become a matter of great interest. Our objective was to derive a consensus among Italian experts on the impact of ETI on the current clinical management of CF lung disease.

METHODS

From December 2021 to April 2022 a panel of Italian experts endorsed by the national CF scientific society derived and graded a set of statements on the pulmonary management of adults with cystic fibrosis through a modified Delphi methodology.

RESULTS

The panel produced 13 statements exploring possible modifications in the fields of inhaled antibiotics and mucoactives; airway clearance and physical activity; chronic macrolides and bronchodilators; and lung transplant referral. The areas that the experts considered most urgent to explore were the impact of ETI on the role of inhaled antibiotics and lung transplant.

CONCLUSIONS

The list of priorities that emerged from this study could be useful to guide and inform clinical research on the most urgent area of impact of ETI on CF lung disease and its clinical management.

Impact of Elexacaftor/Tezacaftor/Ivacaftor on Healthcare Resource Utilization and Associated Costs Among People With Cystic Fibrosis in the US: A Retrospective Claims Analysis

INTRODUCTION

Cystic fibrosis (CF) is a life-limiting genetic disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) is a CFTR modulator (CFTRm) that targets the underlying cause of CF. Based on safety and efficacy demonstrated in clinical trials, ELX/TEZ/IVA is approved in the US for the treatment of CF in people aged ≥ 2 years who have ≥ 1 F508del-CFTR mutation or a CFTR mutation that is responsive to ELX/TEZ/IVA based on in vitro data. While ELX/TEZ/IVA demonstrated unprecedented improvements in lung function and dramatic reductions in pulmonary exacerbations (PEx) and associated hospitalizations in clinical trials, a limited number of studies have examined the impact of ELX/TEZ/IVA on healthcare resource utilization (HCRU) and associated costs in a real-world setting. The aim of this retrospective study was to evaluate changes in PEx, HCRU, and associated non-CFTRm healthcare costs following initiation of ELX/TEZ/IVA among people with CF aged ≥ 12 years in the US.

METHODS

We evaluated the rates of PEx, HCRU, and associated costs before and after initiation of ELX/TEZ/IVA in people with CF aged ≥ 12 years using data from the Merative MarketScan® Commercial Claims and Encounters Database and the Merative Multi-State Medicaid Database from April 21, 2019 to December 31, 2020. Because the study period included time following the onset of the COVID-19 pandemic, we limited our primary analysis to the period prior to the pandemic (October 21, 2019 to March 12, 2020). Outcomes following the onset of the pandemic (March 13 to December 31, 2020) were examined in an exploratory analysis.

RESULTS

In both commercially insured and Medicaid-insured people with CF, ELX/TEZ/IVA was associated with reductions in PEx, hospitalizations, and associated costs prior to the COVID-19 pandemic, and these reductions were maintained following the onset of the pandemic.

CONCLUSIONS

These findings suggest that ELX/TEZ/IVA reduces the burden and costs associated with PEx and hospitalizations in people with CF.

Trials and tribulations of highly effective modulator therapies in cystic fibrosis

Highly effective modulator therapies (HEMTs) have revolutionised the management approach of most patients living with cystic fibrosis (CF) who have access to these therapies. Clinical trials have reported significant improvements across multiorgan systems, with patients surviving longer. However, there are accumulating case reports and observational data describing various adverse events following initiation of HEMTs including drug-to-drug interactions, drug induced liver injury, Stevens-Johnson syndrome, and neurocognitive symptoms including psychosis and depression, which have required discontinuation of therapy. Current clinical trials are assessing efficacy in younger patients with CF, yet long-term studies are also required to better understand the safety profile in the real-world setting across all ages and the impact of HEMT dose alteration or discontinuation.

Prime editing-mediated correction of the CFTR W1282X mutation in iPSCs and derived airway epithelial cells

A major unmet need in the cystic fibrosis (CF) therapeutic landscape is the lack of effective treatments for nonsense CFTR mutations, which affect approximately 10% of CF patients. Correction of nonsense CFTR mutations via genomic editing represents a promising therapeutic approach. In this study, we tested whether prime editing, a novel CRISPR-based genomic editing method, can be a potential therapeutic modality to correct nonsense CFTR mutations. We generated iPSCs from a CF patient homozygous for the CFTR W1282X mutation. We demonstrated that prime editing corrected one mutant allele in iPSCs, which effectively restored CFTR function in iPSC-derived airway epithelial cells and organoids. We further demonstrated that prime editing may directly repair mutations in iPSC-derived airway epithelial cells when the prime editing machinery is efficiently delivered by helper-dependent adenovirus (HDAd). Together, our data demonstrated that prime editing may potentially be applied to correct CFTR mutations such as W1282X.

A Novel Co-Culture Model Reveals Enhanced CFTR Rescue in Primary Cystic Fibrosis Airway Epithelial Cultures with Persistent Pseudomonas aeruginosa Infection

People with cystic fibrosis (pwCF) suffer from chronic and recurring bacterial lung infections that begin very early in life and contribute to progressive lung failure. CF is caused by mutations in the CF transmembrane conductance regulator (CFTR) gene, which encodes an ion channel important for maintaining the proper hydration of pulmonary surfaces. When CFTR function is ablated or impaired, airways develop thickened, adherent mucus that contributes to a vicious cycle of infection and inflammation. Therapeutics for pwCF, called CFTR modulators, target the CFTR defect directly, restoring airway surface hydration and mucociliary clearance. However, even with CFTR modulator therapy, bacterial infections persist. To develop a relevant model of diseased airway epithelium, we established a primary human airway epithelium culture system with persistent Pseudomonas aeruginosa infection. We used this model to examine the effects of CFTR modulators on CFTR maturation, CFTR function, and bacterial persistence. We found that the presence of P. aeruginosa increased CFTR mRNA, protein, and function. We also found that CFTR modulators caused a decrease in P. aeruginosa burden. These results demonstrate the importance of including live bacteria to accurately model the CF lung, and that understanding the effects of infection on CFTR rescue by CFTR modulators is critical to evaluating and optimizing drug therapies for all pwCF.

Late Diagnosis in the Era of Universal Newborn Screening Negatively Affects Short- and Long-Term Growth and Health Outcomes in Infants with Cystic Fibrosis

Newborn screening for cystic fibrosis was fully implemented in the US by 2010, but delays in timeliness of evaluation for infants with positive newborn screening tests persist. Through evaluation of national patient registry data, we determined that late initiation of cystic fibrosis care is associated with poorer long-term nutritional outcomes.

Impact of intrinsic and extrinsic risk factors on early-onset lung disease in cystic fibrosis

BACKGROUND

Although respiratory pathology is known to develop in young children with cystic fibrosis (CF), the determinants of early-onset lung disease have not been elucidated.

OBJECTIVE

We aimed to determine the impact of potential intrinsic and extrinsic risk factors during the first 3 years of life, testing the hypothesis that both contribute significantly to early-onset CF lung disease.

DESIGN

We studied 104 infants born during 2012-2017, diagnosed through newborn screening by age 3 months, and evaluated comprehensively to 36 months of age. Lung disease manifestations were quantified with a new scoring system known as CFELD for Cystic Fibrosis Early-onset Lung Disease. The variants in the cystic fibrosis transmembrane conductance regulator (CFTR) gene were determined and categorized. Whole genome sequencing was performed on each subject and the data transformed to polygenic risk scores (PRS) that aggregate variants associated with lung function. Extrinsic factors included socioeconomic status (SES) indicators and environmental experiences such as exposures to smoking, pets, and daycare.

RESULTS

We found by univariate analysis that CFTR genotype and genetic modifiers aggregated by the PRS method were significantly associated with early-onset CF lung disease. Ordinal logistic regression analysis demonstrated that high and stable SES (maternal education ≥community college, stable 2-parent home, and not receiving Medicaid) and better growth (weight-for-age and height-for-age z-scores) reduced risks, while exposure to smoking and daycare ≥20 h/week increased the risk of CFELD severity.

CONCLUSIONS

Extrinsic, modifiable determinants are influential early and potentially as important as the intrinsic risk factors in the onset of CF lung disease.

Inflammatory Activity of Epithelial Stem Cell Variants from Cystic Fibrosis Lungs Is Not Resolved by CFTR Modulators

Rationale: CFTR (cystic fibrosis transmembrane conductance regulator) modulator drugs restore function to mutant channels in patients with cystic fibrosis (CF) and lead to improvements in body mass index and lung function. Although it is anticipated that early childhood treatment with CFTR modulators will significantly delay or even prevent the onset of advanced lung disease, lung neutrophils and inflammatory cytokines remain high in patients with CF with established lung disease despite modulator therapy, underscoring the need to identify and ultimately target the sources of this inflammation in CF lungs. Objectives: To determine whether CF lungs, like chronic obstructive pulmonary disease (COPD) lungs, harbor potentially pathogenic stem cell "variants" distinct from the normal p63/Krt5 lung stem cells devoted to alveolar fates, to identify specific variants that might contribute to the inflammatory state of CF lungs, and to assess the impact of CFTR genetic complementation or CFTR modulators on the inflammatory variants identified herein. Methods: Stem cell cloning technology developed to resolve pathogenic stem cell heterogeneity in COPD and idiopathic pulmonary fibrosis lungs was applied to end-stage lungs of patients with CF (three homozygous CFTR:F508D, one CFTR F508D/L1254X; FEV1, 14-30%) undergoing therapeutic lung transplantation. Single-cell-derived clones corresponding to the six stem cell clusters resolved by single-cell RNA sequencing of these libraries were assessed by RNA sequencing and xenografting to monitor inflammation, fibrosis, and mucin secretion. The impact of CFTR activity on these variants after CFTR gene complementation or exposure to CFTR modulators was assessed by molecular and functional studies. Measurements and Main Results: End-stage CF lungs display a stem cell heterogeneity marked by five predominant variants in addition to the normal lung stem cell, of which three are proinflammatory both at the level of gene expression and their ability to drive neutrophilic inflammation in xenografts in immunodeficient mice. The proinflammatory functions of these three variants were unallayed by genetic or pharmacological restoration of CFTR activity. Conclusions: The emergence of three proinflammatory stem cell variants in CF lungs may contribute to the persistence of lung inflammation in patients with CF with advanced disease undergoing CFTR modulator therapy.

Elexacaftor/Tezacaftor/Ivacaftor Improves Bronchial Artery Dilatation Detected by Magnetic Resonance Imaging in Patients with Cystic Fibrosis

Rationale: Magnetic resonance imaging (MRI) detects improvements in mucus plugging and bronchial wall thickening, but not in lung perfusion in patients with cystic fibrosis (CF) treated with elexacaftor/tezacaftor/ivacaftor (ETI). Objectives: To determine whether bronchial artery dilatation (BAD), a key feature of advanced lung disease, indicates irreversibility of perfusion abnormalities and whether BAD could be reversed in CF patients treated with ETI. Methods: A total of 59 adults with CF underwent longitudinal chest MRI, including magnetic resonance angiography twice, comprising 35 patients with CF (mean age, 31 ± 7 yr) before (MRI1) and after (MRI2) at least 1 month (mean duration, 8 ± 4 mo) on ETI therapy and 24 control patients with CF (mean age, 31 ± 7 yr) without ETI. MRI was assessed using the validated chest MRI score, and the presence and total lumen area of BAD were assessed with commercial software. Results: The MRI global score was stable in the control group from MRI1 to MRI2 (mean difference, 1.1 [-0.3, 2.4]; P = 0.054), but it was reduced in the ETI group (-10.1 [-0.3, 2.4]; P < 0.001). In the control and ETI groups, BAD was present in almost all patients at baseline (95% and 94%, respectively), which did not change at MRI2. The BAD total lumen area did not change in the control group from MRI1 to MRI2 (1.0 mm2 [-0.2, 2.2]; P = 0.099) but decreased in the ETI group (-7.0 mm2 [-8.9, -5.0]; P < 0.001). This decrease correlated with improvements in the MRI global score (r = 0.540; P < 0.001). Conclusions: Our data show that BAD may be partially reversible under ETI therapy in adult patients with CF who have established disease.

Update on Cystic Fibrosis in Pediatric Patients

PURPOSE OF REVIEW

Cystic fibrosis is an inherited, multisystem disease that affects the gastrointestinal system in numerous ways. This article reviews the nutritional, gastrointestinal, and hepatobiliary manifestations of cystic fibrosis with an emphasis on the effects of CFTR modulator therapy.

RECENT FINDINGS

The life expectancy of individuals with cystic fibrosis has increased substantially in recent years. CFTR modulator therapy improves pulmonary function and results in weight gain. An individualized approach to nutrition is encouraged. Pancreatic exocrine function may improve with intervention early in life. The use of non-invasive methods to screen for hepatobiliary involvement is recommended. Highly effective CFTR modulators lead to increased survival and improved quality of life for many individuals. Their effects on gastrointestinal symptoms and hepatobiliary disease are not fully understood. Patient-reported outcome measures and biomarkers are important clinical endpoints for studying the effects of modulators.

Improvement in Lung Clearance Index and Chest Computed Tomography Scores with Elexacaftor/Tezacaftor/Ivacaftor Treatment in People with Cystic Fibrosis Aged 12 Years and Older - The RECOVER Trial

Rationale: Clinical trials have shown that use of elexacaftor/tezacaftor/ivacaftor (ETI) is associated with improvements in sweat chloride, pulmonary function, nutrition, and quality of life in people with cystic fibrosis (CF). Little is known about the impact of ETI on ventilation inhomogeneity and lung structure. Objectives: RECOVER is a real-world study designed to measure the impact of ETI in people with CF. The primary endpoints were lung clearance (lung clearance index; LCI2.5) and FEV1. Secondary endpoints included spirometry-controlled chest computed tomography (CT) scores. Methods: The study was conducted in seven sites in Ireland and the United Kingdom. Participants ages 12 years and older who were homozygous for the F508del mutation (F508del/F508del) or heterozygous for F508del and a minimum-function mutation (F508del/MF) were recruited before starting ETI and were followed up over 12 months. LCI2.5 was measured using nitrogen multiple breath washout (MBW) at baseline and at 6 and 12 months. Spirometry was performed as per the criteria of the American Thoracic Society and the European Respiratory Society. Spirometry-controlled chest CT scans were performed at baseline and at 12 months. CT scans were scored using the Perth Rotterdam Annotated Grid Morphometric Analysis (PRAGMA) system. Other outcome measures include weight, height, Cystic Fibrosis Quality of Life Questionnaire-Revised (CFQ-R), and sweat chloride. Measurements and Main Results: One hundred seventeen people with CF ages 12 and older were recruited to the study. Significant improvements were seen in LCI scores (-2.5; 95% confidence interval [CI], -3.0, -2.0) and in the percents predicted for FEV1 (8.9; 95% CI, 7.0, 10.9), FVC (6.6; 95% CI, 4.9, 8.3), and forced expiratory flow between 25% and 75% of expired volume (12.4; 95% CI, 7.8, 17.0). Overall PRAGMA-CF scores reflecting airway disease improved significantly (-3.46; 95% CI, -5.23, -1.69). Scores for trapped air, mucus plugging, and bronchial wall thickening improved significantly, but bronchiectasis scores did not. Sweat chloride levels decreased in both F508del/F508del (-43.1; 95% CI, -47.4, -38.9) and F508del/MF (-42.8; 95% CI, -48.5, -37.2) groups. Scores on the Respiratory Domain of the CFQ-R improved by 14.2 points (95% CI, 11.3, 17.2). At 1 year, sweat chloride levels were significantly lower for the F508del/F508del group compared with scores for the F508del/MF group (33.93 vs. 53.36, P < 0.001). Conclusions: ETI is associated with substantial improvements in LCI2.5, spirometry, and PRAGMA-CF CT scores in people with CF ages 12 years and older. ETI led to improved nutrition and quality of life. People in the F508del/F508del group had significantly lower sweat chloride on ETI treatment compared with the F508del/MF group. Clinical trial registered with www.clinicaltrials.gov (NCT04602468).

Cystic fibrosis liver disease in the post-modulator era

PURPOSE OF REVIEW

Highly effective modulators of cystic fibrosis transmembrane conductance regulator (CFTR) function have had dramatic impact on pulmonary and nutritional outcomes in persons with cystic fibrosis (pwCF). The impact on liver disease in pwCF was not the focus of the registration trials. The purpose of this review is to assess the current literature on the impact of HEMT on liver disease, progression, regression, and safety.

RECENT FINDINGS

Short-term studies of HEMT in pwCF have shown that there is no significant impact on the frequency of liver enzyme abnormalities. There is no evidence for significant improvement in liver enzymes over time on HEMT therapy. There is conflicting data on improvement in liver fibrosis determined by fibrosis indices (APRI and GPR) or elastography. One study showed improvement, and another showed worsening in younger (<20 years old) pwCF. There are reports of resolution or improvement in hepatic steatosis. There are rare reports of severe acute hepatitis and one report of hepatic decompensation leading to liver transplantation due to drug-induced liver disease.

SUMMARY

HEMT have not been shown to have a significant impact on improving liver disease or preventing fibrosis with short-term therapy. Longer studies are needed to assess the impact of HEMT on liver disease in pwCF.