Safety, pharmacokinetics, and pharmacodynamics of lumacaftor and ivacaftor combination therapy in children aged 2–5 years with cystic fibrosis homozygous for F508del-CFTR: an open-label phase 3 study

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.

Cystic fibrosis patient characteristics and healthcare resource utilization in Finland using linked registries

Background

Knowledge of prevalence and epidemiology of cystic fibrosis (CF) and healthcare resource use among Finnish people with CF is incomplete.

Methods

We conducted a population-based matched cohort study using retrospective real-world data from linked Finnish national registries. Electronic healthcare data and drug purchases of 102 people with CF were analyzed between January 2015 and December 2019 (follow-up). A 5-fold control population was matched by sex, age, and place of residence. Comorbidities and medication use that occurred at any time during follow-up were assessed; annual rates of hospital service use were adjusted for follow-up.

Results

The prevalence of CF in Finland was 1.85 per 100,000. Median age at diagnosis was 1 year, with 60 % diagnosed at age <2 years and 80 % at age <10 years. Median age at death in people with CF was 31.4 years (n < 5); no controls died. The most common comorbidities included chronic sinusitis (39.2 %), pneumonia (38.2 %), diabetes (20.6 %), and nasal polyps (18.6 %). The most purchased medications were antibiotics (99.0 %) and pancreatic enzymes (84.3 %). The annualized rate of hospital visits was higher in people with CF vs controls (outpatient: mean [SD], 17.4 [14.5] vs 0.9 [3.3]; median, 13.6 vs 0.4, respectively; inpatient: mean [SD], 1.0 [1.66] vs 0.03 [0.14]; median, 0.34 vs 0, respectively).

Conclusions

The prevalence of CF in Finland is remarkably low, likely reflecting unique population characteristics and, in part, delayed diagnosis. Antibiotic use is frequent among Finnish people with CF. Inpatient hospital visits are >30 times higher in people with CF than matched controls.

Impact of lumacaftor/ivacaftor on nutrition and growth in modulator-naïve children over 24 weeks

BACKGROUND

Cystic fibrosis transmembrane conductance regulator (CFTR) modulators improve nutritional status and are of importance in achieving normal growth among younger children with CF. The study was designed to examine CFTR modulator-associated changes in nutrition status, including bile acids and fatty acids after lumacaftor/ivacaftor therapy for 24 weeks.

METHODS

Children 2 to 5.9 years were recruited from US and Canadian CF Centers. Eligible children were lumacaftor/ivacaftor naïve and approved to initiate therapy. Anthropometrics, diet, energy expenditure, nutrition biomarkers, pancreatic status, serum and fecal calprotectin, serum bile acids and plasma fatty acids were measured. Changes from baseline at 12 and 24 weeks were examined using mixed effects linear regression modeling.

RESULTS

Weight-for-age z-score (WAZ) increased at 12 (0.15 ± 0.1, p = 0.01) and 24 weeks (0.23 ± 0.1, p = 0.001) from baseline following modulator therapy. Head circumference-for-age (HCZ) increased at 12 weeks compared to baseline (0.22 ± 0.1, p = 0.03) and subscapular Z score increased from baseline at 24 weeks following therapy (0.33 ± 0.1, p = 0.02). There were no changes in energy expenditure. Serum total bile acids (6.7 ± 2.0, p = 0.001), chenodeoxycholic acid (CDCA) (2.4 ± 1.1, p = 0.001), and cholic acid (CA) (3.5 ± 0.8, p < 0.0001) increased at 24 weeks compared to baseline. Fecal calprotectin decreased at 12 and 24 weeks compared to baseline (-463 ± 310, p = 0.03 and 566 ± 347, p = 0.047). A number of plasma fatty acids changed over the course of 24 weeks of therapy. Noteably, alpha-linolenic acid (ALA) decreased at 12 and 24 weeks (-24 ± 10,p = 0.03 and -18 ± 10, p = 0.02, respectively).

CONCLUSIONS

Overall, young children experienced favorable changes in nutritional and growth, with the exception of plasma ALA status in the first 24 weeks of lumacaftor/ivacaftor therapy.

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.

Improved Nutritional Outcomes and Gastrointestinal Symptoms in Adult Cystic Fibrosis Patients Treated with Elexacaftor/Tezacaftor/Ivacaftor

INTRODUCTION

Cystic fibrosis transmembrane conductance regulator modulator therapy improves nutritional status and quality of life. Clinical trials have shown pancreatic insufficiency conversion, mostly in pediatric patients treated with ivacaftor. Studies with elexacaftor/tezacaftor/ivacaftor (ETI) in older patients have not suggested restoration of exocrine pancreas function, but quality data in adults are lacking. Our aim was to show the effect of ETI in adults with cystic fibrosis (CF) on nutritional status and digestive function. We hypothesized improvement of nutritional parameters and gastrointestinal symptoms, reduction of pancreatic enzyme replacement therapy, but uncertain improvement in exocrine pancreatic function.

METHODS

We prospectively enrolled adults with CF treated with ETI from August 2021 to June 2022. We measured anthropometric parameters, laboratory nutritional markers, change of fecal elastase, pancreatic enzymes replacement therapy needs, and gastrointestinal symptoms.

RESULTS

In the cohort of 29 patients (mean age 29.1 years), 82.8% suffered exocrine pancreatic insufficiency. After ETI, mean BMI increased by 1.20 kg/m2 (p < 0.001), mean body weight by 3.51 kg (p < 0.001), albumin by 2.81 g/L, and prealbumin by 0.06 (both p < 0.001). Only 1 patient, initially pancreatic insufficient (4.5%, p < 0.001), developed pancreatic sufficiency, indicated by increased fecal elastase from 45 μg/g to 442.1 μg/g. Mean change in lipase substitution decreased by 1,969 units/kg/day (p < 0.001) and stools frequency by 1.18 per day (p < 0.001).

CONCLUSION

Our data suggest increased nutritional parameters, lower pancreatic substitution requirements, and improved defecation in adult CF patients on ETI. Improvement in exocrine pancreatic function might be mutation-specific and needs further study.

Diagnosis and Management of Gastrointestinal Manifestations in Children with Cystic Fibrosis

Cystic fibrosis (CF) is primarily known for its pulmonary consequences, which are extensively explored in the existing literature. However, it is noteworthy that individuals with CF commonly display gastrointestinal (G-I) manifestations due to the substantial presence of the cystic fibrosis transmembrane conductance regulator (CFTR) protein in the intestinal tract. Recognized as pivotal nonpulmonary aspects of CF, G-I manifestations exhibit a diverse spectrum. Identifying and effectively managing these manifestations are crucial for sustaining health and influencing the overall quality of life for CF patients. This review aims to synthesize existing knowledge, providing a comprehensive overview of the G-I manifestations associated with CF. Each specific G-I manifestation, along with the diagnostic methodologies and therapeutic approaches, is delineated, encompassing the impact of innovative treatments targeting the fundamental effects of CF on the G-I tract. The findings underscore the imperative for prompt diagnosis and meticulous management of G-I manifestations, necessitating a multidisciplinary team approach for optimal care and enhancement of the quality of life for affected individuals. In conclusion, the authors emphasize the urgency for further clinical studies to establish a more robust evidence base for managing G-I symptoms within the context of this chronic disease. Such endeavors are deemed essential for advancing understanding and refining the clinical care of CF patients with G-I manifestations.

CFTR Modulators: From Mechanism to Targeted Therapeutics

People with cystic fibrosis (CF) suffer from a multi-organ disorder caused by loss-of-function variants in the gene encoding the epithelial anion channel cystic fibrosis transmembrane conductance regulator (CFTR). Tremendous progress has been made in both basic and clinical sciences over the past three decades since the identification of the CFTR gene. Over 90% of people with CF now have access to therapies targeting dysfunctional CFTR. This success was made possible by numerous studies in the field that incrementally paved the way for the development of small molecules known as CFTR modulators. The advent of CFTR modulators transformed this life-threatening illness into a treatable disease by directly binding to the CFTR protein and correcting defects induced by pathogenic variants. In this chapter, we trace the trajectory of structural and functional studies that brought CF therapies from bench to bedside, with an emphasis on mechanistic understanding of CFTR modulators.

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.

[Cystic fibrosis: Epidemiology, clinical manifestations, diagnosis and treatment]

Cystic fibrosis is a genetic and multisystemic disease. The main comorbidity in adulthood is respiratory involvement, with the presence of bronchiectasis, chronic bronchial infection and airflow obstruction. Until a decade ago, treatments were aimed at favoring secretion drainage, reducing respiratory exacerbations, controlling chronic bronchial infection and slowing functional deterioration, but with the advent of cystic fibrosis transmembrane conductance regulator (CFTR) modulators, the cystic fibrosis paradigm has changed. This novel treatment goes a step further in the management of this disease, it is able to improve the production of defective CFTR protein and increase its expression on the cell surface, thus achieving a better functioning of ion exchange, fluidizing respiratory secretions and reducing airflow obstruction. In addition, there are currently different lines of research aimed at correcting the genetic defect that causes cystic fibrosis.

Changes in fecal elastase-1 following initiation of CFTR modulator therapy in pediatric patients with cystic fibrosis

BACKGROUND

Improvement in exocrine pancreatic function in persons with CF (pwCF) on cystic fibrosis transmembrane conductance regulator (CFTR) modulators has been documented in clinical trials using fecal pancreatic elastase-1 (FE-1). Our group endeavored to evaluate real-world data on FE-1 in children on CFTR modulator therapy at three pediatric cystic fibrosis (CF) centers.

METHODS

Pediatric pwCF were offered FE-1 testing if they were on pancreatic enzyme replacement therapy (PERT) and on CFTR modulator therapy according to their center's guideline. FE-1 data were collected retrospectively. The primary outcome was absolute change in FE-1.

RESULTS

70 pwCF were included for analysis. 53 had baseline and post-modulator FE-1 values. There was a significant increase in FE-1 from median 25 mcg/g (IQR 25-60) at baseline to 57 mcg/g (IQR 20-228) post-modulator (p<0.001 by Wilcoxon matched pairs), with an absolute change in FE-1 of median 28 mcg/g (IQR -5-161) and mean 93.5 ± 146.8 mcg/g. Age was negatively correlated with change in FE-1 (Spearman r=-0.48, p<0.001). 15 pwCF (21%) had post-modulator FE-1 values ≥200 mcg/g, consistent with pancreatic sufficiency (PS). The PS group was significant for younger age at initiation of first CFTR modulator and a higher baseline FE-1.

CONCLUSIONS

Most pwCF experienced an increase in FE-1 while receiving CFTR modulator treatment and a small percentage demonstrated values reflective of PS. These data suggest that PS may be attained in those that initiated modulator therapy at a younger age or had a higher baseline FE-1. FE-1 testing is suggested for children on any CFTR modulator therapy.

Rhinorrhea and increased chloride secretion through the CFTR chloride channel-a systematic review

PURPOSE

Allergic and non-allergic rhinorrhea in the forms of acute or chronic rhinosinusitis can mean a watery nasal discharge that is disabling. Primary objective was to review the evidence supporting the hypothesis that rhinorrhea is due to increased chloride secretion through the CFTR chloride channel.

METHODS

The structure of the evidence review followed the EQUATOR Reporting Guidelines. Databases searched from inception to February 2022 included Pubmed, EMBASE and the Cochrane library using keywords "Rhinorrhea", "chloride", "chloride channel", "CFTR" and "randomized controlled trial". Quality assessment was according to the Oxford Centre for Evidence-based Medicine.

RESULTS

49 articles were included. They included randomized controlled trials out of which subsets of data with the outcome of rhinorrhea on 6038 participants were analysed and in vitro and animal studies. The review revealed that drugs, which activate CFTR are associated with rhinorrhea. Viruses, which cause rhinorrhea like rhinovirus were found to activate CFTR. The chloride concentration in nasal fluid showed an increase in patients with viral upper respiratory tract infection. Increased hydrostatic tissue pressure, which is an activator of CFTR was observed in allergic upper airway inflammation. In this condition exhaled breath condensate chlorine concentration was found to be significantly increased. Drugs, which can reduce CFTR function including steroids, anti-histamines, sympathomimetic and anticholinergic drugs reduced rhinorrhea in randomized controlled trials.

CONCLUSIONS

A model of CFTR activation-mediated rhinorrhea explains the effectiveness of anticholinergic, sympathomimetic, anti-histamine and steroid drugs in reducing rhinorrhea and opens up avenues for further improvement of treatment by already known specific CFTR inhibitors.

Nutritional management of people living with cystic fibrosis throughout life and disease continuum: Changing times, new challenges

Cystic fibrosis (CF) is a genetic disease caused by mutations in the gene encoding for the ion channel cystic fibrosis transmembrane conductance regulator (CFTR). The management of CF disease has evolved in recent decades from treating downstream disease manifestations affecting the airways, the lungs and the gastrointestinal system to addressing the CFTR gene defect. The advent of CFTR modulators, which correct the functionality of the defective CFTR, contributes to reshaping the landscape of CF demographics, prognosis and therapies, including nutritional management. A spectrum of clinical manifestations is emerging within the same patient population where undernutrition and nutritional deficiencies coexist with excessive weight gain and metabolic derangements. Such contrasting presentations challenge current practices, require adjustments to traditional approaches, and involve more individualised interventions. This narrative review examines the current state of knowledge on the nutritional management of people living with cystic fibrosis from early life to adulthood in the era of CFTR modulation.

Nationwide lung function monitoring from infancy in newborn-screened children with cystic fibrosis

Background

Cystic fibrosis (CF) lung disease starts in infancy and can be assessed for structural lung abnormalities using computed tomography or magnetic resonance scans, or for lung function impairment using multiple breath washout (MBW). However, in infancy these two methods are not well correlated. Trajectories of CF lung disease assessed by MBW in infants and toddlers remain poorly described, which is why we aimed to 1) describe the trajectory of lung function, 2) explore risk factors for progression and 3) explore the real-life effect of lumacaftor/ivacaftor.

Methods

This was a nationwide observational cohort study (2018-2021) using data collected as part of the routine clinical surveillance programme (including MBW and monthly endo-laryngeal suction sampling for bacterial pathogens) in children born after implementation of newborn screening for CF (May 2016). Lumacaftor/ivacaftor commenced from age 2 years in children homozygous for F508del. Ventilation distribution efficiency (VDE), recently described to have advantages over lung clearance index (LCI), was reported as the primary MBW outcome after z-score calculations based on published reference data. Mixed effect linear regression models were the main statistical analyses performed in this study.

Results

59 children, aged 2-45 months, contributed with 211 MBW occasions (median (interquartile range (IQR)) 3 (2-5) MBW occasions per child) with a median (IQR) follow-up time of 10.8 (5.2-22.3) months. An overall mean annual deterioration rate of -0.50 (95% CI -0.78- -0.22) z-VDE was observed, starting from an estimated mean z-VDE of -1.68 (95% CI -2.15- -1.22) at age 0.0 years (intercept). Pseudomonas aeruginosa "ever" (n=14, MBWs 50) had a significantly worse z-VDE trajectory versus P. aeruginosa "never" (mean difference 0.53 (95% CI 0.16-0.89) per year; p=0.0047) and lumacaftor/ivacaftor treatment (n=22, MBWs 46) significantly improved the trajectory of z-VDE (mean difference 1.72 (95% CI 0.79-2.66) per year; p=0.0004), leading to a stable mean z-VDE trajectory after start of treatment.

Conclusions

Infants and toddlers with CF demonstrated progressive deterioration in z-VDE over the first years of life. P. aeruginosa isolation "ever" was associated with an accelerated deterioration in lung function, while lumacaftor/ivacaftor therapy significantly improved and stabilised the trajectory.

Liquid chromatographic determination of lumacaftor in the presence of ivacaftor and identification of five novel degradation products using high-performance liquid chromatography ion trap time-of-flight mass spectrometry

Lumacaftor is a transmembrane conductance regulator potentiator drug, prescribed for the treatment of cystic fibrosis in patients who are homozygous for the F508del mutation. Quantitation of lumacaftor besides its degradation products and ivacaftor was achieved on a fused-core silica particle column packed with pentafluorophenylpropyl stationary phase (Ascentis Express F5, 2.7 μm particle size 100 mm × 4.6 mm; Supelco) using gradient elution (A: 0.1% [v/v] formic acid in water, B: 0.1% [v/v] formic acid in acetonitrile [the mobile phase pH 2.5]). A constant flow rate at 1 mL/min was applied, and the detection was realized using a photodiode array detector set at 216 nm. The pseudo tablet formulation of the lumacaftor/ivacaftor fixed-dose combination preparation, namely, Orkambi®, was prepared in vitro and used for the analytical performance validation and method application studies. In addition, five novel degradation products, four of which even have no Chemical Abstracts Services registry number, were identified using high-resolution mass spectrometry instrument, and their possible mechanisms of formation were proposed. According to current literature, this paper can be regarded as the most comprehensive liquid chromatographic study on lumacaftor determination, among its counterparts.

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).

Spirometric and anthropometric improvements in response to elexacaftor/tezacaftor/ivacaftor depending on age and lung disease severity

Introduction: Triple-combination cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapy with elexacaftor/tezacaftor/ivacaftor (ETI) was introduced in August 2020 in Germany for people with CF (pwCF) ≥12 years (yrs.) of age and in June 2021 for pwCF ≥6 yrs of age. In this single-center study, we analyzed longitudinal data on the percent-predicted forced expiratory volume (ppFEV1) and body-mass-index (BMI) for 12 months (mo.) after initiation of ETI by linear mixed models and regression analyses to identify age- and severity-dependent determinants of response to ETI. Methods: We obtained data on 42 children ≥6-11 yrs, 41 adolescents ≥12-17 yrs, and 143 adults by spirometry and anthropometry prior to ETI, and 3 and 12 mo. after ETI initiation. Data were stratified by the age group and further sub-divided into age-specific ppFEV1 impairment. To achieve this, the age strata were divided into three groups, each according to their baseline ppFEV1: lowest 25%, middle 50%, and top 25% of ppFEV1. Results: Adolescents and children with more severe lung disease prior to ETI (within the lowest 25% of age-specific ppFEV1) showed higher improvements in lung function than adults in this severity group (+18.5 vs. +7.5; p = 0.002 after 3 mo. and +13.8 vs. +7.2; p = 0.012 after 12 mo. of ETI therapy for ≥12-17 years and +19.8 vs. +7.5; p = 0.007 after 3 mo. for children ≥6-11 yrs). In all age groups, participants with more severe lung disease showed higher BMI gains than those with medium or good lung function (within the middle 50% or top 25% of age-specific ppFEV1). Regression analyses identified age as a predictive factor for FEV1 increase at 3 mo. after ETI initiation, and age and ppFEV1 at ETI initiation as predictive factors for FEV1 increase 12 mo. after ETI initiation. Discussion: We report initial data, which suggest that clinical response toward ETI depends on age and lung disease severity prior to ETI initiation, which argue for early initiation of ETI.

Functional restoration of a CFTR splicing mutation through RNA delivery of CRISPR adenine base editor

Cystic fibrosis (CF) is a genetic disease caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. The 2789+5G>A CFTR mutation is a quite frequent defect causing an aberrant splicing and a non-functional CFTR protein. Here we used a CRISPR adenine base editing (ABE) approach to correct the mutation in the absence of DNA double-strand breaks (DSB). To select the strategy, we developed a minigene cellular model reproducing the 2789+5G>A splicing defect. We obtained up to 70% editing in the minigene model by adapting the ABE to the PAM sequence optimal for targeting 2789+5G>A with a SpCas9-NG (NG-ABE). Nonetheless, the on-target base correction was accompanied by secondary (bystander) A-to-G conversions in nearby nucleotides, which affected the wild-type CFTR splicing. To decrease the bystander edits, we used a specific ABE (NG-ABEmax), which was delivered as mRNA. The NG-ABEmax RNA approach was validated in patient-derived rectal organoids and bronchial epithelial cells showing sufficient gene correction to recover the CFTR function. Finally, in-depth sequencing revealed high editing precision genome-wide and allele-specific correction. Here we report the development of a base editing strategy to precisely repair the 2789+5G>A mutation resulting in restoration of the CFTR function, while reducing bystander and off-target activities.

Cystic Fibrosis: A Review

Importance

Cystic fibrosis, a genetic disorder defined by variants in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, affects more than 30 000 individuals in the US and approximately 89 000 worldwide. Absent or decreased function of the CFTR protein is associated with multiorgan dysfunction and shortened life expectancy.

Observations

CFTR is an anion channel in the apical membrane of epithelial cells. Loss of function leads to obstructed exocrine glands. Of people with cystic fibrosis in the US, approximately 85.5% have the gene variant F508del. Manifestations of cystic fibrosis in patients with the F508del gene variant begin in infancy with steatorrhea, poor weight gain, and respiratory symptoms (coughing, wheezing). As people with cystic fibrosis age, chronic respiratory bacterial infections cause loss of lung function and bronchiectasis. With the availability of universal newborn screening in multiple countries including the US, many people with cystic fibrosis are asymptomatic at diagnosis. With multidisciplinary care teams that included dietitians, respiratory therapists, and social workers, treatment of cystic fibrosis can slow disease progression. Median survival has improved from 36.3 years (95% CI, 35.1-37.9) in 2006 to 53.1 years (95% CI, 51.6-54.7) in 2021. Pulmonary therapies for patients with cystic fibrosis consist of mucolytics (eg, dornase alfa), anti-inflammatories (eg, azithromycin), and antibiotics (such as tobramycin delivered by a nebulizer). Four small molecular therapies, termed CFTR modulators, that facilitate CFTR production and/or function have received regulatory approval. Examples are ivacaftor and elexacaftor-tezacaftor-ivacaftor. For example, in patients with 1 F508del variant, the combination of ivacaftor, tezacaftor, and elexacaftor improved lung function from -0.2% in the placebo group to 13.6% (difference, 13.8%; 95% CI, 12.1%-15.4%) and decreased the annualized estimated rate of pulmonary exacerbations from 0.98 to 0.37 (rate ratio, 0.37; 95% CI, 0.25-0.55). Improved respiratory function and symptoms have lasted up to 144 weeks in postapproval observational studies. An additional 177 variants are eligible for treatment with the elexacaftor-tezacaftor-ivacaftor combination.

Conclusion

Cystic fibrosis affects approximately 89 000 people worldwide and is associated with a spectrum of disease related to exocrine dysfunction, including chronic respiratory bacterial infections and reduced life expectancy. First-line pulmonary therapies consist of mucolytics, anti-inflammatories, and antibiotics, and approximately 90% of people with cystic fibrosis who are 2 years or older may benefit from a combination of ivacaftor, tezacaftor, and elexacaftor.

Effects of lumacaftor-ivacaftor therapy on cystic fibrosis transmembrane conductance regulator function in F508del homozygous patients with cystic fibrosis aged 2-11 years

Rationale: Lumacaftor/ivacaftor was approved for the treatment of patients with cystic fibrosis who are homozygous for F508del aged 2 years and older following positive results from phase three trials. However, the improvement in CFTR function associated with lumacaftor/ivacaftor has only been studied in patients over 12 years of age, while the rescue potential in younger children is unknown. Methods: In a prospective study, we aimed to evaluate the effect of lumacaftor/ivacaftor on the CFTR biomarkers sweat chloride concentration and intestinal current measurement as well as clinical outcome parameters in F508del homozygous CF patients 2-11 years before and 8-16 weeks after treatment initiation. Results: A total of 13 children with CF homozygous for F508del aged 2-11 years were enrolled and 12 patients were analyzed. Lumacaftor/ivacaftor treatment reduced sweat chloride concentration by 26.8 mmol/L (p = 0.0006) and showed a mean improvement in CFTR activity, as assessed by intestinal current measurement in the rectal epithelium, of 30.5% compared to normal (p = 0.0015), exceeding previous findings of 17.7% of normal in CF patients homozygous for F508del aged 12 years and older. Conclusion: Lumacaftor/ivacaftor partially restores F508del CFTR function in children with CF who are homozygous for F508del, aged 2-11 years, to a level of CFTR activity seen in patients with CFTR variants with residual function. These results are consistent with the partial short-term improvement in clinical parameters.

Managing cystic fibrosis in children aged 6-11yrs: a critical review of elexacaftor/tezacaftor/ivacaftor combination therapy

INTRODUCTION

Cystic fibrosis is a life-limiting, autosomal recessive genetic disorder resulting in multi-organ disease due to CF transmembrane conductance regulator (CFTR) protein dysfunction. CF treatment previously focused on mitigation of disease signs and symptoms. The recent introduction of highly effective CFTR modulators, for which ~90% of people with CF are CFTR variant-eligible, has resulted in substantial health improvements.

AREAS COVERED

In this review, we will describe the clinical trials leading to approval of the highly effective CFTR modulator, elexacaftor-tezacaftor-ivacaftor (ETI), with a focus on the safety and efficacy of this treatment in children aged 6-11 years.

EXPERT OPINION

The use of ETI in variant-eligible children aged 6-11 is associated with marked clinical improvements with a favorable safety profile. We anticipate that introduction of ETI in early childhood may result in the prevention of pulmonary, gastrointestinal, and endocrine complications from CF, consequently leading to previously unimaginable gains in the quality and quantity of life. However, there is an urgent need to develop effective treatments for the remaining 10% of people with CF who are not eligible or unable to tolerate ETI treatment, and to increase access of ETI to more pwCF across the world.

Brazilian guidelines for the pharmacological treatment of the pulmonary symptoms of cystic fibrosis. Official document of the Sociedade Brasileira de Pneumologia e Tisiologia (SBPT, Brazilian Thoracic Association)

Cystic fibrosis (CF) is a genetic disease that results in dysfunction of the CF transmembrane conductance regulator (CFTR) protein, which is a chloride and bicarbonate channel expressed in the apical portion of epithelial cells of various organs. Dysfunction of that protein results in diverse clinical manifestations, primarily involving the respiratory and gastrointestinal systems, impairing quality of life and reducing life expectancy. Although CF is still an incurable pathology, the therapeutic and prognostic perspectives are now totally different and much more favorable. The purpose of these guidelines is to define evidence-based recommendations regarding the use of pharmacological agents in the treatment of the pulmonary symptoms of CF in Brazil. Questions in the Patients of interest, Intervention to be studied, Comparison of interventions, and Outcome of interest (PICO) format were employed to address aspects related to the use of modulators of this protein (ivacaftor, lumacaftor+ivacaftor, and tezacaftor+ivacaftor), use of dornase alfa, eradication therapy and chronic suppression of Pseudomonas aeruginosa, and eradication of methicillin-resistant Staphylococcus aureus and Burkholderia cepacia complex. To formulate the PICO questions, a group of Brazilian specialists was assembled and a systematic review was carried out on the themes, with meta-analysis when applicable. The results obtained were analyzed in terms of the strength of the evidence compiled, the recommendations being devised by employing the GRADE approach. We believe that these guidelines represent a major advance to be incorporated into the approach to patients with CF, mainly aiming to favor the management of the disease, and could become an auxiliary tool in the definition of public policies related to CF.

Standards of care for CFTR variant-specific therapy (including modulators) for people with cystic fibrosis

Cystic fibrosis (CF) has entered the era of variant-specific therapy, tailored to the genetic variants in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene. CFTR modulators, the first variant-specific therapy available, have transformed the management of CF. The latest standards of care from the European CF Society (2018) did not include guidance on variant-specific therapy, as CFTR modulators were becoming established as a novel therapy. We have produced interim standards to guide healthcare professionals in the provision of variant-specific therapy for people with CF. Here we provide evidence-based guidance covering the spectrum of care, established using evidence from systematic reviews and expert opinion. Statements were reviewed by key stakeholders using Delphi methodology, with agreement (≥80%) achieved for all statements after one round of consultation. Issues around accessibility are discussed and there is clear consensus that all eligible people with CF should have access to variant-specific therapy.

Dual CFTR modulator therapy efficacy in the real world: lessons for the future

Few diseases have undergone such transformative changes in the past four decades as cystic fibrosis. Cystic fibrosis has become the first example of the successful development of mutation-specific drugs. These drugs, known as cystic fibrosis transmembrane conductance regulator (CFTR) modulators, which improve the function of the CFTR channel, have been able to advance incrementally the overall positive development of therapeutic options in cystic fibrosis in only the last 10 years [1].

Stringent analyses caution against drawing conclusions about the real-world efficacy of CFTR modulator therapy too earlyhttps://bit.ly/3dJt6no

Experience of using lumacaftor/ivacaftor in children with cystic fibrosis in the Astrakhan region

Background. Targeted therapy in patients with cystic fibrosis, which aims to restore the function of the cystic fibrosis transmembrane conductance regulator protein, is currently revolutionary in the treatment of the disease. The first drug available in Russia for the treatment of patients with this genetic disease is lumacaftor/ivacaftor (Orkambi®), which was registered on December 2, 2020.

The aim. To study the efficacy of lumacaftor/ivacaftor during 12 weeks of administration in children in Astrakhan region.

Materials and methods. This article presents the clinical experience of Orkambi medicine use in 3 children with F508del/F508del genotype and a severe course of cystic fibrosis for 12 weeks. According to the study design, such indices as body mass index, indexes of external respiratory function, character of respiratory tract microbiota, level of chloride in sweat fluid and pancreatic elastase in feces, dynamics of biochemical blood indexes were evaluated. The study was performed within the time periods specified in the study protocol, namely, before the start of therapy, 2, 4, and 12 weeks of treatment.

Results. Two patients had a decrease in sweat test values by 11 and 19 mmol/l from the baseline, a significant increase in forced vital capacity of lungs. One patient had an adverse event in the form of hepatobiliary disorders manifested by increased liver transaminase activity, which was the reason for discontinuing the drug.

Conclusions. The short-term experience of using pathogenetic therapy with lumacaftor/ ivacaftor in children in the Astrakhan region demonstrated both the expected effect on chlorine channel function and the possibility of side effects, including severe ones, that can lead to withdrawal of the drug.

Cystic fibrosis transmembrane conductance regulator modulators and the exocrine pancreas: A scoping review

BACKGROUND

Cystic fibrosis transmembrane conductance regulator (CFTR) modulators improve pulmonary outcomes in subjects with cystic fibrosis (CF); however, the effects on pancreatic manifestations are not well characterized. We hypothesized that CFTR modulators would improve measures of exocrine pancreatic function and outcomes.

METHODS

We performed a systematic search to identify studies reporting measures of the exocrine pancreas in humans treated with CFTR modulators. Only studies reporting baseline and on-treatment assessments were included.

RESULTS

Of 630 identified studies, 41 met inclusion criteria. CFTR modulators reduced acute pancreatitis events by 85% overall (rate ratio 0.15, 95% confidence interval (CI) 0.04, 0.52), with a greater effect seen in the subgroup with pancreas sufficient CF (PS-CF) (rate ratio 0.13 (95% CI 0.03, 0.53). Among 293 subjects with baseline and on-treatment evaluation of pancreas sufficiency, 253 were pancreas insufficient at baseline and 54 (21.3%) converted to pancreas sufficiency. Of 32 subjects with baseline FE-1 values <200 mcg/g, 16 (50%) increased to ≥200 mcg/g. Serum trypsin decreased by a mean of 565.9 ng/mL (standard deviation (SD) 311.8), amylase decreased by 38.2 U/L (SD 57.6), and lipase decreased by 232.3 U/L (SD 247.7).

CONCLUSIONS

CFTR modulator use reduces acute pancreatitis frequency and improves indirect measures of exocrine pancreas function. Future interventional studies that evaluate the mechanism and impact of CFTR modulators on acute pancreatitis and pancreas sufficiency in patients with CFTR dysfunction are warranted.

Going the Extra Mile: Why Clinical Research in Cystic Fibrosis Must Include Children

This is an exciting time for research and novel drug development in cystic fibrosis. However, rarely has the adage, “Children are not just little adults” been more relevant. This article is divided into two main sections. In the first, we explore why it is important to involve children in research. We discuss the potential benefits of understanding a disease and its treatment in children, and we highlight that children have the same legal and ethical right to evidence-based therapy as adults. Additionally, we discuss why extrapolation from adults may be inappropriate, for example, medication pharmacokinetics may be different in children, and there may be unpredictable adverse effects. In the second part, we discuss how to involve children and their families in research. We outline the importance and the complexities of selecting appropriate outcome measures, and we discuss the role co-design may have in improving the involvement of children. We highlight the importance of appropriate staffing and resourcing, and we outline some of the common challenges and possible solutions, including practical tips on obtaining consent/assent in children and adolescents. We conclude that it is unethical to simply rely on extrapolation from adult studies because research in young children is challenging and that research should be seen as a normal part of the paediatric therapeutic journey.

An Update on CFTR Modulators as New Therapies for Cystic Fibrosis

Over the past decade there have been significant developments in the field of Cystic Fibrosis Transmembrane Regulator modulator drugs. Following treatment in patients with cystic fibrosis with common gating mutations using the potentiator drug ivacaftor, successive development of corrector drugs used in combination has led to highly effective modulator therapy being available to more than 85% of the cystic fibrosis population over 12 years of age in the form of elexacaftor/tezacaftor/ivacaftor. In this article, we review the evidence from clinical trials and mounting real-world observational and registry data that demonstrates the impact highly effective modulators have on both pulmonary and extra-pulmonary manifestations of cystic fibrosis. As clinical trials progress to younger patient groups, we discuss the challenges to demonstrating drug efficacy in early life, and also consider practicalities of drug development in an ever-shrinking modulator-naïve population. Drug-drug interactions are an important consideration in people with cystic fibrosis, where polypharmacy is commonplace, but also as the modulated population look to remain healthier for longer, we identify trials that aim to address treatment burden too. Inequity of care, through drug cost or ineligibility for modulators by genotype, is widening without apparent strategies to address this; however, we present evidence of hopeful early-stage drug development for non-modulatable genes and summarise the current state of gene-therapy development.

Changing paradigms in the treatment of gastrointestinal complications of cystic fibrosis in the era of cystic fibrosis transmembrane conductance regulator modulators

Cystic fibrosis (CF) - although primarily a lung disease - also causes a variety of gastrointestinal manifestations which are important for diagnosis, prognosis and quality of life. All parts of the gastrointestinal tract can be affected by CF. Besides the well-known pancreatic insufficiency, gastroesophageal reflux disease, liver disease and diseases of the large intestine are important pathologies that impact on prognosis and also impair quality of life. Diagnosis and management of gastrointestinal manifestations will be discussed in this review. Since optimisation of CF therapy is associated with a significantly longer life-span of CF patients nowadays, also gastrointestinal malignancies, which are more common in CF than in the non-CF population need to be considered. Furthermore, novel evidence on the role of the gut microbiome in CF is emerging. The introduction of cystic fibrosis transmembrane conductance regulator (CFTR) protein modulators gives hope for symptom alleviation and even cure of gastrointestinal manifestations of CF.

The impact of FDA and EMA regulatory decision-making process on the access to CFTR modulators for the treatment of cystic fibrosis

Background

Over the past decade, a new class of drugs called CFTR (cystic fibrosis transmembrane conductance regulator) modulators have shown to be able to improve clinical outcomes in patient with Cystic Fibrosis. In this analysis, we have extensively reviewed the regulatory pathways and decisions adopted by FDA and EMA to speed up the development, the review and the approval of these drugs, with the aim of identifying possible clinical and public health implications associated with differences.

Results

CFTR modulators have been developed towards addressing three main genetic domains: (1) F508del homozygous (F508del/F508del), (2) F508del heterozygous, and (3) genotypes not carrying F508del mutation; and expanded from adult to paediatric population. Programs to expedite the reviewing and licensing of CFTR modulators were extensively adopted by FDA and EMA. All CFTR modulators have been licensed in the US as orphan drugs, but in the EU the orphan status for LUM/IVA was not confirmed at the time of marketing authorization as results from the pivotal trial were not considered clinically significant. While FDA and EMA approved CFTR modulators on the basis of results from phase III double-blind RCTs, main differences were found on the extension of indications: FDA accepted non-clinical evidence considering a recovery of the CFTR function ≥ 10% based on chloride transport, a reliable indicator to correlate with improvement in clinical outcomes. By contrast, EMA did not deem preclinical data sufficient to expand the label of CFTR modulators without confirmatory clinical data.

Conclusions

Regulators played an important role in fostering the development and approval of CFTR modulators. However, differences were found between FDA and EMA in the way of reviewing and licensing CFTR modulators, which extended beyond semantics affecting patients’ eligibility and access: FDA’s approach was more mechanistic/biology-driven while the EMA’s one was more oriented by clinical evidence. This might refer to the connection between the EMA and the Member States, which tends to base decisions on pricing and reimbursement on clinical data rather than pre-clinical ones. Here we have proposed a two-step personalized-based model to merge the ethical commitment of ensuring larger access to all potential eligible patients (including those harboring very rare mutations) with the one of ensuring access to clinically assessed and effective medicines through Real World Data.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02350-5.

CFTR Modulator Therapies: Potential Impact on Airway Infections in Cystic Fibrosis

Cystic Fibrosis (CF) is an autosomal recessive disease caused by mutations in the gene encoding for the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) protein, expressed on the apical surface of epithelial cells. CFTR absence/dysfunction results in ion imbalance and airway surface dehydration that severely compromise the CF airway microenvironment, increasing infection susceptibility. Recently, novel therapies aimed at correcting the basic CFTR defect have become available, leading to substantial clinical improvement of CF patients. The restoration or increase of CFTR function affects the airway microenvironment, improving local defence mechanisms. CFTR modulator drugs might therefore affect the development of chronic airway infections and/or improve the status of existing infections in CF. Thus far, however, the full extent of these effects of CFTR-modulators, especially in the long-term remains still unknown. This review aims to provide an overview of current evidence on the potential impact of CFTR modulators on airway infections in CF. Their role in affecting CF microbiology, the susceptibility to infections as well as the potential efficacy of their use in preventing/decreasing the development of chronic lung infections and the recurrent acute exacerbations in CF will be critically analysed.

Precision Medicine Based on CFTR Genotype for People with Cystic Fibrosis

Cystic fibrosis (CF) is an autosomal recessive genetic condition that is caused by variants in the cystic fibrosis transmembrane conductance regulator gene. This causes multisystem disease due to dysfunction of the cystic fibrosis transmembrane conductance regulator (CFTR) ion channel at the apical surface of epithelia. Until recently, treatment was directed at managing the downstream effects in affected organs, principally improving airway clearance and treating infection in the lungs and improving malabsorption in the gastrointestinal tract. Care delivered by multidisciplinary teams has yielded incremental improvements in outcomes. However, the development of small-molecule CFTR modulator drugs over the last decade has heralded a new era of CF therapeutics. Modulators target the underlying defect and improve CFTR function. Either monotherapy or a combination of modulators is used depending on the specific genotype and class of CFTR disease-causing variants that an individual has. Both ivacaftor and the ivacaftor/tezacaftor/elexacaftor combination have been demonstrated to be associated with clinically very significant benefits in randomised trials and have rapidly been made available as part of standard care in many countries. CFTR modulators represent one of the best examples of precision medicine to date. They are expensive, however, and equity of access to them worldwide remains an issue. Studies and approvals are also ongoing for children under the age of 6 years for ivacaftor/tezacaftor/elexacaftor. Furthermore, no modulators are available for around 10% of the people with CF. In this review, we firstly summarise the genetics, pathophysiology and clinical problems associated with CF. We then discuss the development of CFTR modulators and key clinical trials to support their use along with other potential future therapeutic approaches.

Recent advances in the early treatment of cystic fibrosis: Bridging the gap to highly effective modulator therapy

Highly effective modulator therapy (HEMT) for cystic fibrosis (CF) has been touted as one of the greatest advances to date in CF care. As these therapies are now available for many older children and adults with CF, marked improvement of their nutritional status, pulmonary and gastrointestinal symptoms has been observed. However, most infants and younger children are not current candidates for HEMT due to age and/or cystic fibrosis transmembrane conductance regulator (CFTR) mutation. For these young children, it is essential to provide rigorous monitoring and care to avoid potential disease sequelae while awaiting HEMT availability. The following article highlights recent advances in the care of infants and young children with CF with regard to surveillance and treatment of nutritional, pulmonary, and gastrointestinal disorders. Recent clinical trials in this population are also reviewed.

The Changing Face of Cystic Fibrosis: An Update for Anesthesiologists

Cystic fibrosis (CF) is the most common fatal genetic disease in North America. While CF is more common among Whites, it is increasingly being recognized in other races and ethnicities. Although there is no cure, life expectancy has steadily improved, with the median survival exceeding 46 years in the United States. There are now more adults than children with CF in the United States. CF is caused by mutations in a gene that encodes the cystic fibrosis transmembrane conductance regulator (CFTR) protein, expressed in many epithelial cells. More than 2100 CFTR mutations have been linked to CF, and newer CFTR modulator drugs are being used to improve the production, intracellular processing, and function of the defective CFTR protein. CF is a multisystem disease that affects primarily the lungs, pancreas, hepatobiliary system, and reproductive organs. Anesthesiologists routinely encounter CF patients for various surgical and medical procedures, depending on the age group. This review article focuses on the changing epidemiology of CF, advances in the classification of CFTR mutations, the latest innovations in CFTR modulator therapies, the impact of the coronavirus disease pandemic, and perioperative considerations that anesthesiologists must know while caring for patients with CF.

Treatment of Polarized Cystic Fibrosis Airway Cells With HGF Prevents VX-661-Rescued F508del-CFTR Destabilization Caused by Prolonged Co-exposure to VX-770

Cystic fibrosis (CF), the most common inherited disease in Caucasians, is caused by mutations in CFTR, the most frequent of which is F508del. F508del causes ER retention and degradation of the mutant CFTR protein, but also defective channel gating and decreased half-life at the plasma membrane. Despite the recent successes with small-molecule CFTR modulator drugs, the folding-corrector/gating-potentiator drug combinations approved for CF individuals carrying F508del-CFTR have sometimes produced severe side effects. Previously, we showed that a prolonged, 15-days treatment of polarized bronchial epithelial monolayers with the VX-809+VX-770 combination resulted in epithelial dedifferentiation effects that we found were caused specifically by VX-809. Moreover, prolonged VX-770 exposure also led to the destabilization of VX-809-rescued F508del-CFTR. Notably, co-treatment with the physiological factor HGF prevented VX-809-mediated epithelial differentiation and reverted the destabilizing effect of VX-770 on VX-809-rescued CFTR. Here, we show that prolonged treatment with VX-661, a second-generation corrector developed based on VX-809 structure, does not perturb epithelial integrity of polarized bronchial epithelial monolayers. Yet, its efficacy is still affected by co-exposure to VX-770, the potentiator present in all VX-661-containing combination therapies approved in the United States and Europe for treatment of F508del-CFTR carriers. Importantly, we found that co-treatment with HGF still ameliorated the impact of VX-770 in F508del-CFTR functional rescue by VX-661, without increasing cell proliferation (Ki-67) or altering the overall expression of epithelial markers (ZO-1, E-cadherin, CK8, CK18). Our findings highlight the importance of evaluating the cellular effects of prolonged exposure to CFTR modulators and suggest that the benefits of adding HGF to current combination therapies should be further investigated.

Effectiveness and Safety of Cystic Fibrosis Transmembrane Conductance Regulator Modulators in Children With Cystic Fibrosis: A Meta-Analysis

BACKGROUND AND AIM

Cystic fibrosis (CF) is a genetic disease that is difficult to treat and caused by dysfunction of the cystic fibrosis transmembrane conductance regulator (CFTR) protein. Small molecules have been used to treat the symptom caused by CFTR mutations by restoring CFTR protein function. However, the data on children with CF are scarce. This meta-analysis aimed to evaluate the effectiveness and safety of this therapy in children diagnosed with CF.

MATERIALS AND METHODS

Relevant studies were identified through searching medical databases before April 1, 2022. The primary outcomes of ppFEV₁, lung clearance index_2.5 (LCI_2.5), sweat chloride concentration (SwCI), and Cystic Fibrosis Questionnaire-Revised (CFQ-R) score were pooled and analyzed. The secondary outcomes were nutritional status (weight, BMI, stature, and their z-score) and adverse events under therapy.

RESULTS

A total of twelve studies were included. Compared with the placebo group, the pooled outcome of the ppFEV1, LCI_2.5, SwCI, and CFQ-R score were improved by 7.91 {[95% confidence interval (CI), 3.71-12.12], -1.00 (95% CI, -1.38 to -0.63), -35.22 (95% CI, -55.51 to -14.92), and 4.45 (95% CI, 2.31-6.59), respectively}. Compared with the placebo group, the pooled result of the change in weight was improved by 1.53 (95% CI, 0.42-2.63). All the aforementioned results were also improved in single-arm studies. No clear differences in adverse events were found between CFTR modulator therapy and the placebo group.

CONCLUSION

CFTR modulators could improve multiaspect function in children with CF and result in comparable adverse events.

A screening tool to identify risk for bronchiectasis progression in children with cystic fibrosis

BACKGROUND

The marked heterogeneity in cystic fibrosis (CF) disease complicates the selection of those most likely to benefit from existing or emergent treatments.

OBJECTIVE

We aimed to predict the progression of bronchiectasis in preschool children with CF.

METHODS

Using data collected up to 3 years of age, in the Australian Respiratory Early Surveillance Team for CF cohort study, clinical information, chest computed tomography (CT) scores, and biomarkers from bronchoalveolar lavage were assessed in a multivariable linear regression model as predictors for CT bronchiectasis at age 5-6.

RESULTS

Follow-up at 5-6 years was available in 171 children. Bronchiectasis prevalence at 5-6 was 134/171 (78%) and median bronchiectasis score was 3 (range 0-12). The internally validated multivariate model retained eight independent predictors accounting for 37% (adjusted R² ) of the variance in bronchiectasis score. The strongest predictors of future bronchiectasis were: pancreatic insufficiency, repeated intravenous treatment courses, recurrent lower respiratory infections in the first 3 years of life, and lower airway inflammation. Dichotomizing the resulting prediction score at a bronchiectasis score of above the median resulted in a diagnostic odds ratio of 13 (95% confidence interval [CI], 6.3-27) with positive and negative predictive values of 80% (95% CI, 72%-86%) and 77% (95% CI, 69%-83%), respectively.

CONCLUSION

Early assessment of bronchiectasis risk in children with CF is feasible with reasonable precision at a group level, which can assist in high-risk patient selection for interventional trials. The unexplained variability in disease progression at individual patient levels remains high, limiting the use of this model as a clinical prediction tool.

Congenital etiologies of exocrine pancreatic insufficiency

Congenital exocrine pancreatic insufficiency is a rare condition. In a vast majority of patients, exocrine dysfunction occurs as part of a multisystemic disease, the most prevalent being cystic fibrosis and Shwachman-Bodian-Diamond syndrome. Recent fundamental studies have increased our understanding of the pathophysiology of these diseases. Exocrine pancreatic dysfunction should be considered in children with failure to thrive and fatty stools. Treatment is mainly supportive and consists of pancreatic enzyme replacement and liposoluble vitamins supplementation.

Standards of Nutritional Care for Patients with Cystic Fibrosis: A Methodological Primer and AGREE II Analysis of Guidelines

Although many Clinical Practice Guidelines (CPGs) have been published for the care of patients with Cystic Fibrosis (CF), including a variety of nutrition recommendations, the quality of these CPGs has never been evaluated. The aim of this study was to compare, review, and critically appraise CPGs for the nutritional management of CF, throughout the lifespan. We searched PubMed, Guidelines International Network (GIN), ECRI Institute, and Guidelines Central for CPGs, with information on the nutritional management of CF. Retrieved CPGs were appraised by three independent reviewers, using the Appraisal of Guidelines, Research and Evaluation II (AGREE II) instrument and checklist. A total of 22 CPGs (seven solely nutrition oriented), by 14 different publishers, were retrieved. The Thoracic Society of Australia and New Zealand CPGs scored the highest overall quality (94.4%), while the Paediatric Gastroenterology Society/Dietitians Association of Australia CPGs had the lowest score (27.8%). Great variation in AGREE II domain-specific scores was observed in all CPGs, suggesting the existence of different strengths and weaknesses. Despite the availability of several CPGs, many appear outdated, lacking rigor, transparency, applicability, and efficiency, while incorporating bias. Considering that CPGs adherence is associated with better outcomes and the need for improving life expectancy in patients with CF, the development of CPGs of better quality is deemed necessary.

CFTR modulators increase risk of acute pancreatitis in pancreatic insufficient patients with cystic fibrosis

Patients with pancreatic insufficient cystic fibrosis rarely develop acute pancreatitis due to insufficient acinar reserve. We describe a series of five patients under the age of 18 (range 8-16 years) with pancreatic insufficient cystic fibrosis who developed a phenotype in keeping with acute pancreatitis following initiation of CFTR modulator therapy. This occurred at a median of 30 months following CFTR modulator initiation. 3/5 of these patients also developed pancreatic sufficiency or at least an intermediary pancreas status, indicated by fecal elastases above 100 μg/g. This series highlights a mostly unrecognized potential side effect of this therapy as well as the potential of CFTR modulator therapies to improve exocrine pancreatic function, even in adolescent patients.

State of the Art on Approved Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Modulators and Triple-Combination Therapy

Cystic fibrosis (CF) is the most common life-limiting inherited disease in Caucasian populations, affecting approximately 80,000 people worldwide. CF is a complex multi-organ monogenic autosomal recessive disorder caused by a mutation in cystic fibrosis transmembrane conductance regulator (CFTR) gene. Since the discovery of the CFTR gene in 1989, more than 2000 mutations have been identified so far and about 240 can cause CF. Until recently, the treatment for CF was aimed to prevent and manage the manifestations of CFTR dysfunction, primarily recurrent pulmonary infections and pancreatic exocrine failure. Over the past few decades, the therapeutic approach to CF has been revolutionized by the development of a new class of small molecules called CFTR modulators that target specific defects caused by mutations in the CFTR gene. CFTR modulators have been shown to change profoundly the clinical course of the CF, leading to meaningful improvements in the lives of a large proportion of people of CF heterozygous for F508del, especially if started in young children. Further studies are needed to extend the use of triple CFTR modulation therapy also for young children in order to prevent the irreversible effects of the disease and for patients with very rare mutations with a personalized approach to treatment.

The Intestinal Microbiome and Cystic Fibrosis Transmembrane Conductance Regulator Modulators: Emerging Themes in the Management of Gastrointestinal Manifestations of Cystic Fibrosis

PURPOSE OF REVIEW

While commonly associated with pulmonary manifestations, cystic fibrosis (CF) is a systemic disease with wide-ranging effects on the gastrointestinal (GI) tract. This article reviews major recent updates in gastroenterological CF care and research.

RECENT FINDINGS

The high burden of GI symptoms in CF has led to recent studies assessing GI-specific symptom questionnaires and scoring systems. Intestinal dysbiosis potentially contributes to gastrointestinal symptoms in patients with CF and an increased risk of gastrointestinal cancers in CF. An increased incidence of colorectal cancer (CRC) has led to CF-specific CRC screening and surveillance recommendations. Pharmacologic therapies targeting specific cystic fibrosis transmembrane conductance regulator (CFTR) mutations have shown promise in treating GI manifestations of CF. New research has highlighted the importance of intestinal dysbiosis in CF. Future studies should assess whether CFTR modulators affect the gut microbiome and whether altering the gut microbiome will impact GI symptoms and GI cancer risk.

Lumacaftor-ivacaftor effects on cystic fibrosis-related liver involvement in adolescents with homozygous F508 del-CFTR

BACKGROUND

The effects of lumacaftor-ivacaftor on cystic fibrosis transmembrane conductance regulator (CFTR)-associated liver disease remain unclear. The objective of the study was to describe the effect of this treatment on features of liver involvement in a cystic fibrosis (CF) adolescent population homozygous for F508del.

METHODS

Clinical characteristics, liver blood tests, abdominal ultrasonography (US), and pancreas and liver proton density fat fraction (PDFF) by magnetic resonance imaging, were obtained at treatment initiation and at 12 months for all patients. Biomarkers of CFTR activity (sweat chloride test, nasal potential difference, and intestinal current measurement) were assessed at initiation and at 6 months therapy.

RESULTS

Of the 37 patients who started ivacaftor/lumacaftor treatment, 28 were eligible for analysis. In this group, before treatment initiation, 4 patients were diagnosed with multinodular liver and portal hypertension, 19 with other forms of CF liver involvement, and 5 with no signs of liver involvement. During treatment, no hepatic adverse reactions were documented, and no patient developed liver failure. Serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gammaglutamyl transferase (GGT) decreased significantly following initiation of lumacaftor-ivacaftor, and remained so after 12 months treatment. This was not correlated with changes in clinical status, liver and pancreas US and PDFF, fecal elastase, or lumacaftor-ivacaftor serum levels. The most "responsive" patients demonstrated a significant increase in biomarkers of CFTR activity.

CONCLUSIONS

These results may suggest a potential beneficial effect of CFTR modulators on CF liver disease and warrant further investigation in larger, prospective studies.