Safety, pharmacokinetics, and pharmacodynamics of ivacaftor in patients aged 2-5 years with cystic fibrosis and a CFTR gating mutation (KIWI): an open-label, single-arm study

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.

Review of CFTR modulators 2020

Cystic fibrosis transmembrane conductance regulator (CFTR) modulators are small molecules that directly impact the CFTR protein, improving the function of the CFTR chloride and bicarbonate channel. Beginning in 2012 with the Food and Drug Administration approval of the first CFTR modulator, ivacaftor, this class of medications has had largely positive effects on many outcomes in people with cystic fibrosis (PwCF), including lung function, growth, and other clinical parameters. There have been continued exciting developments in the current research on CFTR modulators, expanding beyond original studies. This first part of a three-part cystic fibrosis (CF) year in review 2020 will focus on research on CFTR modulators. In addition to reviewing new clinical insights, we describe work done on novel outcomes, adverse effects, issues related to cost, and next steps for clinical trials. The review focuses on articles from Pediatric Pulmonology published in 2020, but it includes articles from other journals that are of particular interest to clinicians. New developments in CF research continue to be brought forth to the CF community, deepening the understanding of this disease and improving clinical care.

Cystic fibrosis associated liver disease in children

Cystic fibrosis (CF) is an autosomal recessive disorder caused by mutations in the CF transmembrane conductance regulator gene. CF liver disease develops in 5%-10% of patients with CF and is the third leading cause of death among patients with CF after pulmonary disease or lung transplant complications. We review the pathogenesis, clinical presentations, complications, diagnostic evaluation, effect of medical therapies especially CF transmembrane conductance regulator modulators and liver transplantation in CF associated liver disease.

Small-molecule drugs for cystic fibrosis: Where are we now?

The cystic fibrosis (CF) lung disease is due to the lack/dysfunction of the CF Transmembrane Conductance Regulator (CFTR), a chloride channel expressed by epithelial cells as the main regulator of ion and fluid homeostasis. More than 2000 genetic variation in the CFTR gene are known, among which those with identified pathomechanism have been divided into six VI mutation classes. A major advancement in the pharmacotherapy of CF has been the development of small-molecule drugs hitting the root of the disease, i.e. the altered ion and fluid transport through the airway epithelium. These drugs, called CFTR modulators, have been advanced to the clinics to treat nearly 90% of CF patients, including the CFTR potentiator ivacaftor, approved for residual function mutations (Classes III and IV), and combinations of correctors (lumacaftor, tezacaftor, elexacaftor) and ivacaftor for patients bearing at least one the F508del mutation, the most frequent mutation belonging to class II. To cover the 10% of CF patients without etiological therapies, other novel small-molecule CFTR modulators are in evaluation of their effectiveness in all the CFTR mutation classes: read-through agents for Class I, correctors, potentiators and amplifiers from different companies for Class II-V, stabilizers for Class VI. In alternative, other solute carriers, such as SLC26A9 and SLC6A14, are the focus of intensive investigation. Finally, other molecular targets are being evaluated for patients with no approved CFTR modulator therapy or as means of enhancing CFTR modulatory therapy, including small molecules forming ion channels, inhibitors of the ENaC sodium channel and potentiators of the calcium-activated chloride channel TMEM16A. This paper aims to give an up-to-date overview of old and novel CFTR modulators as well as of novel strategies based on small-molecule drugs. Further investigations in in-vivo and cell-based models as well as carrying out large prospective studies will be required to determine if novel CFTR modulators, stabilizers, amplifiers, and the ENaC inhibitors or TMEM16A potentiators will further improve the clinical outcomes in CF management.

Triple combination cystic fibrosis transmembrane conductance regulator modulator therapy in the real world - opportunities and challenges

PURPOSE OF REVIEW

The purpose of this review is to describe on-going and upcoming real-world studies that will aid the cystic fibrosis (CF) community in understanding the long-term efficacy, safety and challenges in utilizing this therapy and managing care.

RECENT FINDINGS

The triple combination of elexacaftor, tezacaftor and ivacaftor (ETI) has been demonstrated to improve lung function, weight and quality of life in children and adults with CF with at least one copy of Phe508del. Treatment with ETI will potentially be available for approximately 90% of the CF population and change the face of CF.

SUMMARY

In spite of early demonstrations of short-term efficacy and safety, for medications that may be given for much of someone's life, continued assessment of these outcomes is necessary. Furthermore, the CF community must evaluate and address the issues that arise with increased longevity including parenthood, preventive care management and the potential comorbidities of aging.

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.

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.

The Impact of Highly Effective CFTR Modulators on Growth and Nutrition Status

Patients with cystic fibrosis (CF) are at increased risk of malnutrition and growth failure due to multiple factors as a result of suboptimal or absent function of the CFTR chloride channel protein. Dysfunctional CFTR contributes to increased energy expenditure, exocrine pancreatic insufficiency causing impaired dietary macronutrient digestion and absorption, intestinal dysbiosis, and impaired bile acid homeostasis. Poor nutritional status as a result of these mechanisms is associated with decreased lung function, worse clinical outcomes, and ultimately, increased mortality. Nutritional interventions addressing these mechanisms, such as pancreatic enzyme-replacement therapy and enteral caloric supplementation, have improved nutritional status and, by association, clinical outcomes. In the last decade, the advent of medications targeting defective CFTR proteins has revolutionized the care of patients with CF by reducing the overall impact of CFTR dysfunction. Below, we summarize the effects of highly effective CFTR modulators on nutritional status overall as well as specific factors including bile acid metabolism, pancreatic function, energy expenditure, and intestinal dysbiosis. The future of CF nutrition care will require a paradigm shift away from focusing on methods addressing CFTR dysfunction such as excess calorie provision and toward an individualized, holistic approach in the context of specific mutations and CFTR-directed therapy.

Effect of apical chloride concentration on the measurement of responses to CFTR modulation in airway epithelia cultured from nasal brushings

INTRODUCTION

One method for assessing the in vitro response to CFTR-modulating compounds is by analysis of epithelial monolayers in an Ussing chamber, where the apical and basolateral surfaces are isolated and the potential difference, short-circuit current, and transepithelial resistance can be monitored. The effect of a chloride ion gradient across airway epithelia on transepithelial chloride transport and the magnitude of CFTR modulator efficacy were examined.

METHODS

CFTR-mediated changes in the potential difference and transepithelial currents of primary human nasal epithelial cell cultures were quantified in Ussing chambers with either symmetrical solutions or reduced chloride solutions in the apical chamber. CFTR activity in homozygous F508del CFTR epithelia was rescued by treatment with VX-661, C4/C18, 4-phenylbutyrate (4-PBA) for 24 hr at 37°C or by incubation at 29°C for 48 hr.

RESULTS

Imposing a chloride gradient increased CFTR-mediated and CaCC-mediated ion transport. Treatment of F508del CFTR homozygous cells with CFTR modulating compounds increased CFTR activity, which was significantly more evident in the presence of a chloride gradient. This observation was recapitulated with temperature-mediated F508del CFTR correction.

CONCLUSIONS

Imposing a chloride gradient during Ussing chamber measurements resulted in increased CFTR-mediated ion transport in expanded non-CF and F508del CFTR homozygous epithelia. In F508del CFTR homozygous epithelia, the magnitude of response to CFTR modulating compounds or low temperature was greater when assayed with a chloride gradient compared to symmetrical chloride, resulting in an apparent increase in measured efficacy. Future work may direct which methodologies utilized to quantify CFTR modulator response in vitro are most appropriate for the estimation of in vivo efficacy.

Academy of Nutrition and Dietetics: 2020 Cystic Fibrosis Evidence Analysis Center Evidence-Based Nutrition Practice Guideline

The Academy of Nutrition and Dietetics Evidence Analysis Center conducted a systematic review of the literature to develop an evidence-based practice guideline for primary nutrition issues in cystic fibrosis (CF). This guideline is designed to complement and build upon existing evidence-based CF nutrition guidelines. The objective of this guideline was to provide recommendations for registered dietitian nutritionists in the United States delivering medical nutrition therapy to individuals with CF and their families that fill gaps in current evidence-based guidelines on topics that are crucial in order to improve health and prevent disease progression. This guideline provides 28 nutrition recommendations to guide medical nutrition therapy, including nutrition screening, nutrition assessment, and dietary intake. For topics outside the scope of this guideline, practitioners are referred to external, evidence-based recommendations. The CF landscape is evolving rapidly with breakthroughs in cystic fibrosis transmembrane regulator modulators changing CF at a cellular level. Medical nutrition therapy for individuals with CF from infancy through advanced age requires novel and individualized approaches. The Academy Evidence Analysis Library CF guidelines provide a framework for expanding upon current knowledge to determine effective nutrition strategies for individuals with CF through long and healthy futures.

Effectiveness of Elexacaftor/Tezacaftor/Ivacaftor Therapy in Three Subjects with the Cystic Fibrosis Genotype Phe508del/Unknown and Advanced Lung Disease

We evaluated the effectiveness and safety of elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) in three subjects carrying the Phe508del/unknown CFTR genotype. An ex vivo analysis on nasal epithelial cells (NEC) indicated a significant improvement of CFTR gating activity after the treatment. Three patients were enrolled in an ELX/TEZ/IVA managed-access program, including subjects with the highest percent predicted Forced Expiratory Volume in the 1st second (ppFEV₁) < 40 in the preceding 3 months. Data were collected at baseline and after 8, 12 and 24 weeks of follow-up during treatment. All patients showed a considerable decrease of sweat chloride (i.e., meanly about 60 mmol/L as compared to baseline), relevant improvement of ppFEV₁ (i.e., >8) and six-minute walk test, and an increase in body mass index after the first 8 weeks of treatment. No pulmonary exacerbations occurred during the 24 weeks of treatment and all domains of the CF Questionnaire-Revised improved. No safety concerns related to the treatment occurred. This study demonstrates the benefit from the ELX/TEZ/IVA treatment in patients with CF with the Phe508del and one unidentified CFTR variant. The preliminary ex vivo analysis of the drug response on NEC helps to predict the in vivo therapeutic endpoints.

Elexacaftor-Tezacaftor-Ivacaftor Therapy for Cystic Fibrosis Patients with The F508del/Unknown Genotype

The new CFTR modulator combination, elexacaftor/tezacaftor/ivacaftor (Trikafta) was approved by the FDA in October 2019 for treatment of Cystic Fibrosis in patients 6 years of age or older who have at least one F508del mutation in one allele and a minimal-function or another F508del mutation in the other allele. However, there is a group of patients, in addition to those with rare mutations, in which despite the presence of a F508del in one allele, it was not possible to identify any mutation in the other allele. To date, these patients are excluded from treatment with Trikafta in Italy, where the CF patients carrying F508del/unknown represent about 1.3% (71 patients) of the overall Italian CF patients. In this paper we show that the Trikafta treatment of nasal epithelial cells, derived from F508del/Unknown patients, results in a significant rescue of CFTR activity. Based on our findings, we think that the F508del/Unknown patients considered in this study could obtain clinical benefits from Trikafta treatment, and we strongly suggest their eligibility for this type of treatment. This study, adding further evidence in the literature, once again confirms the validity of functional studies on nasal cells in the cystic fibrosis theratyping and personalized medicine.

Breast development in a 7 year old girl with CF treated with ivacaftor: An indication for personalized dosing?

Substantial progress has been made in the treatment of Cystic fibrosis due to introduction of CFTR modulators. However, little is known about the long term side effects of treatment with these drugs. We here present a 7 year old girl with CF who presented with breast development as a rare dose dependent side effect of treatment with ivacaftor and we report data on the correlation between drug plasma concentration and clinical effect, bodyweight, and BSA in 16 patients. Higher plasma concentrations did not correlate with clinical effect, as change in FEV1 and sweat chloride concentration. Patients with low bodyweight or BSA tended to have higher plasma concentrations. This might indicate that the current recommended dose of ivacaftor is at the top of the dose-response curve and that some patients can be treated with lower doses of ivacaftor with similar clinical effect.

Real-World Long-Term Ivacaftor for Cystic Fibrosis in France: Clinical Effectiveness and Healthcare Resource Utilization

Introduction

Ivacaftor is a cystic fibrosis transmembrane conductance regulator (CFTR) potentiator that has demonstrated clinical benefits in phase 3 trials. We report results from a real-world study (BRIO) to assess the effectiveness of ivacaftor in people with cystic fibrosis (pwCF) in France.

Methods

BRIO was an observational study conducted at 35 centers in France. Both pwCF initiating ivacaftor treatment and those already taking ivacaftor were included and prospectively followed for 24 months. The primary objective was to evaluate the effect of ivacaftor on percent predicted forced expiratory volume in 1 s (ppFEV₁); secondary objectives were evaluating the effect of ivacaftor on clinical effectiveness, healthcare resource utilization (HCRU), and safety.

Results

A total of 129 pwCF were enrolled; 58.9% were aged < 18 years; 64.3% had a G551D-CFTR allele. Mean age at ivacaftor initiation was 19.1 years (range, 2–64 years); ppFEV₁ increased by a least squares mean of 8.49 percentage points in the first 6 months and was sustained through 36 months of ivacaftor use. Growth metrics increased during the first 12 months post-ivacaftor and remained stable. The rate of pulmonary exacerbations (PEx) decreased during the 12 months post-ivacaftor compared with the 12 months pre-ivacaftor; estimated rate ratios (95% CI) were 0.57 (0.43–0.75) for PEx events and 0.25 (0.13–0.48) for PEx requiring hospitalization. No new safety concerns were identified; no deaths occurred.

Conclusions

The results from this real-world study of ivacaftor usage in France were consistent with prior clinical trial outcomes, confirming the clinical effectiveness of ivacaftor, as well as an associated reduction in HCRU.

Supplementary Information

The online version contains supplementary material available at 10.1007/s41030-021-00158-5.

New Therapies to Correct the Cystic Fibrosis Basic Defect

Rare diseases affect 400 million individuals worldwide and cause significant morbidity and mortality. Finding solutions for rare diseases can be very challenging for physicians and researchers. Cystic fibrosis (CF), a genetic, autosomal recessive, multisystemic, life-limiting disease does not escape this sad reality. Despite phenomenal progress in our understanding of this disease, treatment remains difficult. Until recently, therapies for CF individuals were focused on symptom management. The discovery of the cystic fibrosis transmembrane conductance regulator (CFTR) gene and its product, a protein present at the apical surface of epithelial cells regulating ion transport, allowed the scientific community to learn about the basic defect in CF and to study potential therapies targeting the dysfunctional protein. In the past few years, promising therapies with the goal to restore CFTR function became available and changed the lives of several CF patients. These medications, called CFTR modulators, aim to correct, potentialize, stabilize or amplify CFTR function. Furthermore, research is ongoing to develop other targeted therapies that could be more efficient and benefit a larger proportion of the CF community. The purpose of this review is to summarize our current knowledge of CF genetics and therapies restoring CFTR function, particularly CFTR modulators and gene therapy.

Cystic fibrosis

Cystic fibrosis is a monogenic disease considered to affect at least 100 000 people worldwide. Mutations in CFTR, the gene encoding the epithelial ion channel that normally transports chloride and bicarbonate, lead to impaired mucus hydration and clearance. Classical cystic fibrosis is thus characterised by chronic pulmonary infection and inflammation, pancreatic exocrine insufficiency, male infertility, and might include several comorbidities such as cystic fibrosis-related diabetes or cystic fibrosis liver disease. This autosomal recessive disease is diagnosed in many regions following newborn screening, whereas in other regions, diagnosis is based on a group of recognised multiorgan clinical manifestations, raised sweat chloride concentrations, or CFTR mutations. Disease that is less easily diagnosed, and in some cases affecting only one organ, can be seen in the context of gene variants leading to residual protein function. Management strategies, including augmenting mucociliary clearance and aggressively treating infections, have gradually improved life expectancy for people with cystic fibrosis. However, restoration of CFTR function via new small molecule modulator drugs is transforming the disease for many patients. Clinical trial pipelines are actively exploring many other approaches, which will be increasingly needed as survival improves and as the population of adults with cystic fibrosis increases. Here, we present the current understanding of CFTR mutations, protein function, and disease pathophysiology, consider strengths and limitations of current management strategies, and look to the future of multidisciplinary care for those with cystic fibrosis.

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

BACKGROUND

Cystic fibrosis transmembrane conductance regulator (CFTR) modulators are disease-modifying medications for cystic fibrosis (CF) and are shown to be efficacious for only specific CFTR mutations. CFTR mutation frequency varies by ancestry, which is different from but related to demographic racial and ethnic group. Eligibility for CFTR modulator therapy has not been previously reported by race and ethnicity.

METHODS

We conducted a cross-sectional study of patients in the 2018 CF Foundation Patient Registry. We analyzed the percentage of patients in each US Census defined racial and ethnic group eligible for CFTR modulators based on CFTR mutations approved by the US FDA and then based on both mutations and FDA approval by age. We compared lung function based on CFTR modulator eligibility and prescription.

FINDINGS

Based on CFTR mutations alone, 92.4% of non-Hispanic White patients, 69.7% of Black/African American patients, 75.6% of Hispanic patients, and 80.5% of other race patients eligible for CFTR modulators. For each CFTR modulator, Black/African American patients were least likely to have eligible mutations, and non-Hispanic White patients were most likely. There was no difference in the disparity between racial and/or ethnic groups with the addition of current FDA approval by age. The lowest pulmonary function in the cohort was seen in non-Hispanic White, Black/African American, and Hispanic patients not eligible for CFTR modulators.

INTERPRETATION

Patients with CF from minority groups are less likely to be eligible for CFTR modulators. Because people with CF who are racial and ethnic minorities have increased disease severity and earlier mortality, this will further contribute to health disparities.

Quantification of Phenotypic Variability of Lung Disease in Children with Cystic Fibrosis

Cystic fibrosis (CF) lung disease has the greatest impact on the morbidity and mortality of patients suffering from this autosomal-recessive multiorgan disorder. Although CF is a monogenic disorder, considerable phenotypic variability of lung disease is observed in patients with CF, even in those carrying the same mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene or CFTR mutations with comparable functional consequences. In most patients with CF, lung disease progresses from childhood to adulthood, but is already present in infants soon after birth. In addition to the CFTR genotype, the variability of early CF lung disease can be influenced by several factors, including modifier genes, age at diagnosis (following newborn screening vs. clinical symptoms) and environmental factors. The early onset of CF lung disease requires sensitive, noninvasive measures to detect and monitor changes in lung structure and function. In this context, we review recent progress with using multiple-breath washout (MBW) and lung magnetic resonance imaging (MRI) to detect and quantify CF lung disease from infancy to adulthood. Further, we discuss emerging data on the impact of variability of lung disease severity in the first years of life on long-term outcomes and the potential use of this information to improve personalized medicine for patients with CF.

Pancreas transplantation for cystic fibrosis: A frequently missed opportunity

Cystic fibrosis (CF) is an inherited autosomal recessive disorder. Despite optimized therapy, the majority of affected individuals ultimately die of respiratory failure. As patients with CF are living longer, extra-pulmonary manifestations may develop including pancreatic failure, which manifests as exocrine insufficiency, and CF-related diabetes (CFRD). Both of these can be managed through pancreas transplantation. Pancreas transplantation is usually performed in combination with another organ, most often with a kidney transplant for end-stage diabetic nephropathy. In the CF patient population, the two settings where inclusion of a pancreas transplant should be considered would be in combination with a lung transplant for CF pulmonary disease, or in combination with a liver for CF-related liver disease with cirrhosis. This report will discuss this topic in detail, including a review of the literature regarding combinations of lung/pancreas and liver/pancreas transplant.

CFTR Modulators: Does One Dose Fit All?

For many people with cystic fibrosis (pwCF), CFTR modulators will be the cornerstone of their treatment. These modulators show robust treatment effects at group level in pwCF with specific mutations. The individual effect however, is variable. In this review we will explain reasons for reconsideration of dosing regimens of CFTR modulating therapy in order to improve treatment response and prevent side effects. Since the effect of a drug depends on pharmacodynamics and pharmacokinetics, pharmacodynamics and pharmacokinetic properties of CFTR modulators will be discussed. Pharmacokinetic-pharmacodynamic relationships will be used to gain insight in dosage response and exposure response relationships. To understand the cause of variation in drug exposure, pharmacokinetic properties that may change due to CF disease will be explained. We show that with current insight, there are conceivable situations that give reason for reconsideration of dosing regimens, however many questions need to be unravelled.

Long-term safety of lumacaftor-ivacaftor in children aged 2-5 years with cystic fibrosis homozygous for the F508del-CFTR mutation: a multicentre, phase 3, open-label, extension study

BACKGROUND

A previous phase 3 study showed that lumacaftor-ivacaftor was generally safe and well tolerated over 24 weeks of treatment in children aged 2-5 years with cystic fibrosis homozygous for the F508del-CFTR mutation. In this study, we aimed to assess the long-term safety of lumacaftor-ivacaftor in a rollover study of children who participated in this previous phase 3 study.

METHODS

In this multicentre, phase 3, open-label, extension study (study 116; VX16-809-116), we assessed safety of lumacaftor-ivacaftor in children included in a previous multicentre, phase 3, open-label study (study 115; VX15-809-115). The study was done at 20 cystic fibrosis care centres in the USA and Canada. Children aged 2-5 years with cystic fibrosis homozygous for the F508del-CFTR mutation who completed 24 weeks of lumacaftor-ivacaftor treatment in study 115 received weight-based and age-based doses of oral lumacaftor-ivacaftor: children weighing less than 14 kg and aged younger than 6 years at study 116 screening received lumacaftor 100 mg-ivacaftor 125 mg every 12 h; children weighing 14 kg or more and aged younger than 6 years at screening received lumacaftor 150 mg-ivacaftor 188 mg every 12 h; and children aged 6 years or older received lumacaftor 200 mg-ivacaftor 250 mg every 12 h. Children received treatment for up to 96 weeks, equivalent to up to 120 weeks of treatment in total from the start of study 115 to completion of study 116. The primary endpoint was the safety and tolerability of the study drug in all participants who had received lumacaftor-ivacaftor for 24 weeks in study 115 and had received at least one dose in study 116. Secondary endpoints included change from baseline in study 115 at week 96 of study 116 in sweat chloride concentration, growth parameters, markers of pancreatic function, and lung clearance index (LCI) parameters in all children who received at least one dose of lumacaftor-ivacaftor in study 116. This study is registered with ClinicalTrials.gov, NCT03125395.

FINDINGS

This extension study ran from May 12, 2017, to July 17, 2019. Of 60 participants enrolled and who received lumacaftor-ivacaftor in study 115, 57 (95%) were included in study 116 and continued to receive the study drug. A total of 47 (82%) of 57 participants completed 96 weeks of treatment. Most participants (56 [98%] of 57) had at least one adverse event during study 116, most of which were mild (19 [33%] participants) or moderate (29 [51%] participants) in severity. The most common adverse events were cough (47 [82%] participants), nasal congestion (25 [44%] participants), pyrexia (23 [40%] participants), rhinorrhoea (18 [32%] participants), and vomiting (17 [30%] participants). A total of 15 (26%) participants had at least one serious adverse event; most were consistent with underlying cystic fibrosis or common childhood illnesses. Respiratory adverse events occurred in five (9%) participants, none of which were serious or led to treatment discontinuation. Elevated aminotransferase concentrations, most of which were mild or moderate in severity, occurred in ten (18%) participants. Three (5%) participants discontinued treatment due to adverse events (two due to increased aminotransferase concentrations [one of whom had concurrent pancreatitis], considered as possibly related to study drug; and one due to gastritis and metabolic acidosis, considered unlikely to be related to study drug). No clinically significant abnormalities or changes were seen in electrocardiograms, vital signs, pulse oximetry, ophthalmological examinations, or spirometry assessments. Improvements in secondary endpoints observed in study 115 were generally maintained up to week 96 of study 116, including improvements in sweat chloride concentration (mean absolute change from study 115 baseline at week 96 of study 116 -29·6 mmol/L [95% CI -33·7 to -25·5]), an increase in growth parameters and pancreatic function, and stable lung function relative to baseline, as measured by the LCI.

INTERPRETATION

Lumacaftor-ivacaftor was generally safe and well tolerated, and treatment effects were generally maintained for the duration of the extension study. These findings support the use of lumacaftor-ivacaftor for up to 120 weeks in young children with cystic fibrosis aged 2 years and older homozygous for the F508del-CFTR mutation.

FUNDING

Vertex Pharmaceuticals Incorporated.

Treatment of Pulmonary Disease of Cystic Fibrosis: A Comprehensive Review

Cystic fibrosis (CF) is a genetic disease that causes absence or dysfunction of a protein named transmembrane conductance regulatory protein (CFTR) that works as an anion channel. As a result, the secretions of the organs where CFTR is expressed are very viscous, so their functionality is altered. The main cause of morbidity is due to the involvement of the respiratory system as a result of recurrent respiratory infections by different pathogens. In recent decades, survival has been increasing, rising by around age 50. This is due to the monitoring of patients in multidisciplinary units, early diagnosis with neonatal screening, and advances in treatments. In this chapter, we will approach the different therapies used in CF for the treatment of symptoms, obstruction, inflammation, and infection. Moreover, we will discuss specific and personalized treatments to correct the defective gene and repair the altered protein CFTR. The obstacle for personalized CF treatment is to predict the drug response of patients due to genetic complexity and heterogeneity of uncommon mutations.

Cystic Fibrosis Lung Disease Modifiers and Their Relevance in the New Era of Precision Medicine

Our understanding of cystic fibrosis (CF) has grown exponentially since the discovery of the cystic fibrosis transmembrane conductance regulator (CFTR) gene in 1989. With evolving genetic and genomic tools, we have come to better understand the role of CFTR genotypes in the pathophysiology of the disease. This, in turn, has paved the way for the development of modulator therapies targeted at mutations in the CFTR, which are arguably one of the greatest advances in the treatment of CF. These modulator therapies, however, do not target all the mutations in CFTR that are seen in patients with CF and, furthermore, a variation in response is seen in patients with the same genotype who are taking modulator therapies. There is growing evidence to support the role of non-CFTR modifiers, both genetic and environmental, in determining the variation seen in CF morbidity and mortality and also in the response to existing therapies. This review focusses on key findings from studies using candidate gene and genome-wide approaches to identify CF modifier genes of lung disease in cystic fibrosis and considers the interaction between modifiers and the response to modulator therapies. As the use of modulator therapies expands and we gain data around outcomes, it will be of great interest to investigate this interaction further. Going forward, it will also be crucial to better understand the relative influence of genomic versus environmental factors. With this understanding, we can truly begin to deliver personalised care by better profiling the likely disease phenotype for each patient and their response to treatment.

Real-World Outcomes of Ivacaftor Treatment in People with Cystic Fibrosis: A Systematic Review

Cystic fibrosis (CF) is a rare, progressive, multi-organ genetic disease. Ivacaftor, a small-molecule CF transmembrane conductance regulator modulator, was the first medication to treat the underlying cause of CF. Since its approval, real-world clinical experience on the use of ivacaftor has been documented in large registries and smaller studies. Here, we systematically review data from real-world observational studies of ivacaftor treatment in people with CF (pwCF). Searches of MEDLINE and Embase identified 368 publications reporting real-world studies that enrolled six or more pwCF treated with ivacaftor published between January 2012 and September 2019. Overall, 75 publications providing data from 57 unique studies met inclusion criteria and were reviewed. Studies reporting within-group change for pwCF treated with ivacaftor consistently showed improvements in lung function, nutritional parameters, and patient-reported respiratory and sino-nasal symptoms. Benefits were evident as early as 1 month following ivacaftor initiation and were sustained over long-term follow-up. Decreases in pulmonary exacerbations, Pseudomonas aeruginosa prevalence, and healthcare resource utilization also were reported for up to 66 months following ivacaftor initiation. In studies comparing ivacaftor treatment to modulator untreated comparator groups, clinical benefits similarly were reported as were decreases in mortality, organ-transplantation, and CF-related complications. The safety profile of ivacaftor observed in these real-world studies was consistent with the well-established safety profile based on clinical trial data. Our systematic review of real-world studies shows ivacaftor treatment in pwCF results in highly consistent and sustained clinical benefit in both pulmonary and non-pulmonary outcomes across various geographies, study designs, patient characteristics, and follow-up durations, confirming and expanding upon evidence from clinical trials.

Ivacaftor in Infants Aged 4 to <12 Months with Cystic Fibrosis and a Gating Mutation. Results of a Two-Part Phase 3 Clinical Trial

Rationale: We previously reported that ivacaftor was safe and well tolerated in cohorts aged 12 to <24 months with cystic fibrosis and gating mutations in the ARRIVAL study; here, we report results for cohorts aged 4 to <12 months.

Objectives: To evaluate the safety, pharmacokinetics, and pharmacodynamics of ivacaftor in infants aged 4 to <12 months with one or more gating mutations.

Methods: ARRIVAL is a single-arm phase 3 study. Infants received 25 mg or 50 mg ivacaftor every 12 hours on the basis of age and weight for 4 days in part A and 24 weeks in part B.

Measurements and Main Results: Primary endpoints were safety (parts A and B) and pharmacokinetics (part A). Secondary/tertiary endpoints (part B) included pharmacokinetics and changes in sweat chloride levels, growth, and markers of pancreatic function. Twenty-five infants received ivacaftor, 12 in part A and 17 in part B (four infants participated in both parts). Pharmacokinetics was consistent with that in older groups. Most adverse events were mild or moderate. In part B, cough was the most common adverse event (n = 10 [58.8%]). Five infants (part A, n = 1 [8.3%]; part B, n = 4 [23.5%]) had serious adverse events, all of which were considered to be not or unlikely related to ivacaftor. No deaths or treatment discontinuations occurred. One infant (5.9%) experienced an alanine transaminase elevation >3 to ≤5× the upper limit of normal at Week 24. No other adverse trends in laboratory tests, vital signs, or ECG parameters were reported. Sweat chloride concentrations and measures of pancreatic obstruction improved.

Conclusions: This study of ivacaftor in the first year of life supports treating the underlying cause of cystic fibrosis in children aged ≥4 months with one or more gating mutations.

Clinical trial registered with clinicaltrials.gov (NCT02725567).

Drug development for cystic fibrosis

The first regulatory approval for a drug developed specifically for cystic fibrosis (CF) occurred in 1993, and since then, several other drugs have been approved. Median predicted survival in people with CF in the United States has increased from approximately 30 years to 44.4 years over that same period. Highly effective modulators of the cystic fibrosis transmembrane conductance regulator became available to approximately 90% of people with CF ages 12 years and older in the United States in 2019 and in Europe in 2020. These transformative therapies will surely reduce morbidity and further extend longevity. The drug development pipeline is filled with therapies that address most aspects of CF disease. As survival and CF therapies advance, and the complexity of CF care increases, the process of drug development has become more sophisticated. In addition, detecting meaningful changes in outcome measures has become more difficult as the health status of people with CF improves. Innovative approaches are required to continue to advance drug development in CF. This review provides a general overview of drug development from the preclinical phase through Phase IV. Special considerations with respect to CF are integrated into the discussion of each phase of drug development. As CF care evolves, drug development must continue to evolve as well, until a one-time cure is available to all people with CF.

Entering the era of highly effective modulator therapies

Since the discovery of the gene responsible for cystic fibrosis (CF) in 1989, hopes have been pinned on a future with novel therapies tackling the basis of the disease rather than its symptoms. These have become a reality over the last decade with the development through to the clinic of CF transmembrane conductance regulator (CFTR) modulators. These are oral drugs which improve CFTR protein function through either increasing the time the channel pore is open (potentiators) or facilitating its trafficking through the cell to its location on the cell membrane (correctors). The first potentiator, ivacaftor, is now licensed and available clinically in many parts of the world. It is highly effective with impressive clinical impact in the lungs and gastrointestinal tract; longer-term data from patient registries show fewer exacerbations, a slower rate of lung function loss and reduced need for transplantation in patients receiving ivacaftor. However, as a single drug, it is suitable for only a small minority of patients. The commonest CFTR mutation, F508del, requires both correction and potentiation for clinical efficacy. Two dual-agent drugs (lumacaftor/ivacaftor and tezacaftor/ivacaftor) have progressed through to licensing, although their short term impact is more modest than that of ivacaftor; this is likely due to only partial correction of protein misfolding and trafficking. Most recently, triple compounds have been developed: two different corrector molecules (elexacaftor and tezacaftor) which, by addressing different regions in the misfolded F508del protein, more effectively improve trafficking. In addition to large improvements in clinical outcomes in people with two copies of F508del, the combination is sufficiently effective that it works in patients with only one copy of F508del and a second, nonmodulator responsive mutation. For the first time, we thus have a drug suitable for around 85% of people with CF. Even more gains are likely to be possible when these drugs can be used in younger children, although more sensitive outcome measures are needed for this age group. Special consideration is needed for people with very rare mutations; those with nonmodulatable mutation combinations will likely require gene or messenger RNA-based therapeutic approaches, many of which are being explored. Although this progress is hugely to be celebrated, we still have more work to do. The international collaboration between trials networks, pharma, patient organizations, registries, and people with CF is something we are all rightly proud of, but innovative trial design and implementation will be needed if we are to continue to build on this progress and further develop drugs for people with CF.

Challenges in the use of highly effective modulator treatment for cystic fibrosis

The last decade has seen development of oral, small molecule therapies that address the basic cystic fibrosis transmembrane conductance regulator (CFTR) protein defect. Highly effective modulator treatment (HEMT) that is efficacious for a large majority of people living with cystic fibrosis (CF) promises to change the landscape of this chronic life-limiting disease. Some people living with CF have a CFTR genotype that renders them eligible for HEMT, but also have comorbidities that excluded them from the original Phase III clinical trials that led to US Food and Drug Administration approval. The purpose of this review is to address the use of HEMT in challenging situations, including initiation for those with advanced CF lung disease, and use after solid organ transplant, during pregnancy, and for individuals with CFTR-related disorders without a definitive diagnosis of CF.

The Extrapulmonary Effects of Cystic Fibrosis Transmembrane Conductance Regulator Modulators in Cystic Fibrosis

The effects of cystic fibrosis (CF) transmembrane conductance regulator (CFTR) modulators on lung function, pulmonary exacerbations, and quality of life have been well documented. However, CF is a multiorgan disease, and therefore an evidence base is emerging on the systemic effects of CFTR modulators beyond the pulmonary system. This is of great clinical importance, as many of these studies provide proof of concept that CFTR modulators might be used one day to prevent or treat extrapulmonary manifestations stemming from CFTR dysfunction. In this concise review of the literature, we summarize the results of key publications that have evaluated the effects of CFTR modulators on weight and growth, pancreatic function, the gastrointestinal and hepatobiliary systems, sinus disease, bone disease, exercise tolerance, fertility, mental health, and immunity. Although many of these studies have reported beneficial extrapulmonary effects related to the use of ivacaftor (IVA) in patients with CF with at least one gating mutation, most of the evidence is low or very low quality, given the limited number of patients evaluated and the lack of control groups. Based on an even smaller number of studies evaluating the extrapulmonary effects of lumacaftor-IVA, the benefits are less clear. Although limited, these studies may provide the basis for future clinical trials to evaluate CFTR modulators on the extrapulmonary manifestations of CF.

Modulators of CFTR. Updates on clinical development and future directions

Cystic fibrosis (CF) is the most frequent life-limiting autosomal recessive disorder in the Caucasian population. It is due to mutations in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene. Current symptomatic CF therapies, which treat the downstream consequences of CFTR mutations, have increased survival. Better knowledge of the CFTR protein has enabled pharmacologic therapy aiming to restore mutated CFTR expression and function. These CFTR "modulators" have revolutionised the CF therapeutic landscape, with the potential to transform prognosis for a considerable number of patients. This review provides a brief summary of their mechanism of action and presents a thorough review of the results obtained from clinical trials of CFTR modulators.

Early Diagnosis and Intervention in Cystic Fibrosis: Imagining the Unimaginable

Cystic fibrosis is the most common life-shortening genetic disease affecting Caucasians, clinically manifested by fat malabsorption, poor growth and nutrition, and recurrent sinopulmonary infections. Newborn screening programs for cystic fibrosis are now implemented throughout the United States and in many nations worldwide. Early diagnosis and interventions have led to improved clinical outcomes for people with cystic fibrosis. Newer cystic fibrosis transmembrane conductance regulator potentiators and correctors with mutation-specific effects have increasingly been used in children, and these agents are revolutionizing care. Indeed, it is possible that highly effective modulator therapy used early in life could profoundly affect the trajectory of cystic fibrosis lung disease, and primary prevention may be achievable.

A bird eye view on cystic fibrosis: An underestimated multifaceted chronic disorder

Cystic fibrosis (CF) is an autosomal recessive disease which involves the mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. CF involves in the inflammatory processes and is considered as a multisystem disorder that is not confined to lungs, but it also affects other vital organs that leads to numerous co-morbidities. The respiratory disorder in the CF results in mortality and morbidity which is characterized by series of serious events involving mucus hypersecretion, microbial infections, airways obstruction, inflammation, destruction of epithelium, tissue remodeling and terminal lung diseases. Mucins are the high molecular weight glycoproteins important for the viscoelastic properties of the mucus, play a significant role in the disease mechanisms. Determining the functional association between the CFTR and mucins might help to identify the putative target for specific therapeutic approach. In fact, furin enzyme which helps in the entry of novel COVID-19 virus into the cell, is upregulated in CF and this can also serve as a potential target for CF treatment. Moreover, the use of nano-formulations for CF treatment is an area of research being widely studied as they have also demonstrated promising outcomes. The in-depth knowledge of non-coding RNAs like miRNAs and lncRNAs and their functional association with CFTR gene expression and mutation can provide a different range of opportunity to identify the promising therapeutic approaches for CF.

Genomically-guided therapies: A new era for cystic fibrosis

Since the cloning of the CFTR gene 30 years ago, research aiming at understanding how CFTR mutations translate to abnormal synthesis or function of the CFTR protein has opened the way to genomically-guided therapy to improve CFTR function. A CFTR potentiator to enhance CFTR channel function has been approved in 2012 for specific and quite rare mutations. Subsequently, combinations of a corrector to increase CFTR expression at the cell membrane, plus a potentiator, have been approved for patients homozygous for the p.Phe508del mutation. To obtain robust correction of CFTR, new combinations of drugs are being studied. A triple combination associating two correctors and one potentiator is very promising and if data of clinical trials are confirmed, it could be a robust and well tolerated CFTR modulator for patients bearing at least one p.Phe508del mutation. Many other strategies are also in development to make these genomically-guided treatments available to all patients with CF. © 2020 French Society of Pediatrics. Published by Elsevier Masson SAS. All rights reserved.

Physiologically Based Pharmacokinetic Modeling of CFTR Modulation in People with Cystic Fibrosis Transitioning from Mono or Dual Regimens to Triple-Combination Elexacaftor/Tezacaftor/Ivacaftor

INTRODUCTION

The triple-combination (TC) cystic fibrosis transmembrane conductance regulator (CFTR) modulator regimen elexacaftor, tezacaftor, and ivacaftor was shown to be safe and efficacious in phase 3 trials of people with cystic fibrosis (pwCF) ≥ 12 years of age with ≥ 1 F508del-CFTR allele. Here, a simulation study predicted ivacaftor, tezacaftor, and elexacaftor exposures and impacts on CFTR modulation following transition from ivacaftor [a cytochrome P450 3A (CYP3A) substrate], lumacaftor (a CYP3A inducer)/ivacaftor, or tezacaftor/ivacaftor to TC.

METHODS

Physiologically based pharmacokinetic (PBPK) modeling was used to evaluate plasma exposures during transition from mono- or dual-combination CFTR modulator regimens to TC. PBPK models were parameterized using data from human hepatocytes to account for CYP3A induction by lumacaftor and validated to match clinical data from healthy volunteers and pwCF. Using dosing regimens for pwCF ≥ 12 years of age, simulations were performed for ivacaftor, lumacaftor/ivacaftor, and tezacaftor/ivacaftor dosing for 14 days followed by immediate transition to elexacaftor/tezacaftor/ivacaftor dosing for 14 days. Drug exposures during transitions were compared with respective half-maximal effective concentrations (EC50) estimated from efficacy endpoint data from clinical studies.

RESULTS

In simulations of immediate transition from ivacaftor or tezacaftor/ivacaftor to TC, the preceding treatment had no impact on ivacaftor, tezacaftor, or elexacaftor exposures. In simulations of immediate transition from lumacaftor/ivacaftor to TC, ivacaftor exposure decreased to 64% of maximum effective concentration (EC), due to reduction in ivacaftor dose and residual CYP3A4 induction, then returned to 90-95% of maximum EC. Lumacaftor-mediated CYP3A induction resolved within approximately 2 weeks. In all simulations, ivacaftor, tezacaftor, and elexacaftor exposures approached steady state within 2 weeks following transition and, at all times, ivacaftor and ≥ 1 CFTR corrector remained above EC50.

CONCLUSION

PBPK modeling indicates that immediate transition to the elexacaftor/tezacaftor/ivacaftor regimen from an ivacaftor, lumacaftor/ivacaftor, or tezacaftor/ivacaftor regimen results in sustained CFTR modulation in pwCF ≥ 12 years of age.

Persistent recovery of pancreatic function in patients with cystic fibrosis after ivacaftor

Exocrine pancreatic insufficiency (EPI), which leads to malabsorption and poor weight gain, is seen in 85% of patients with cystic fibrosis (CF). EPI is treated with pancreatic enzyme replacement therapy taken with each meal. The highly effective cystic fibrosis transmembrane conductance regulator (CFTR) modulator, ivacaftor, restores CFTR function in patients with responsive mutations. It is a widely held view that EPI in CF is irreversible due to the complete destruction of pancreatic ducts and acinar cells. We describe three pediatric CF patients with EPI who were started on ivacaftor, and subsequently showed evidence of restored exocrine pancreatic function with clinical and biochemical parameters.

Current Treatment Options for Cystic Fibrosis-Related Liver Disease

Cystic Fibrosis-related liver disease (CFLD) has become a leading cause of morbidity and mortality in patients with Cystic Fibrosis (CF), and affects children and adults. The understanding of the pathogenesis of CFLD is key in order to develop efficacious treatments. However, it remains complex, and has not been clarified to the last. The search for a drug might be additionally complicated due to the diverse clinical picture and lack of a unified definition of CFLD. Although ursodeoxycholic acid has been used for decades, its efficacy in CFLD is controversial, and the potential of Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) modulators and targeted gene therapy in CFLD needs to be defined in the near future. This review focuses on the current knowledge on treatment strategies for CFLD based on pathomechanistic viewpoints.

Paediatric pancreatic diseases

Paediatric pancreatic diseases are often under-recognised and may be associated with severe diseases and significant clinical consequences. In recent years, advances have been made in key areas, particularly with the contributions from international societies and study groups focused on paediatric pancreatic disease research. This review focuses on the two key manifestations of pancreatic disorders in childhood, pancreatitis and exocrine pancreatic dysfunction.

Cystic fibrosis and the gut

Cystic fibrosis (CF) is a recessive disease caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. The gene product, CFTR protein, has important manifestations in the intestine, pancreas and hepatobiliary system. Increased survival has caused CF to be primarily an adult disease today. Physicians must be knowledgeable as to the varied phenotype in the gastrointestinal tract. This review will outline the main gastrointestinal manifestations including a section on gastrointestinal malignancy in CF. Novel treatments treating the basic effect in CF are now being introduced and their effects on the gastrointestinal tract are discussed.

Cystic fibrosis - Ten promising therapeutic approaches in the current era of care

INTRODUCTION

Cystic fibrosis (CF) is a genetic disease affecting multiple organ systems. Research and innovations in novel therapeutic agents and health care delivery have resulted in dramatic improvements in quality of life and survival for people with CF. Despite this, significant disease burden persists for many and this is compounded by disparities in treatment access and care which globally necessitates further work to improve outcomes. Because of the advent of numerous therapies which include gene-targeted modulators in parallel with specialized care delivery models, innovative efforts continue.

AREAS COVERED

In this review, we discuss the available data on investigational agents in clinical development and currently available treatments for CF. We also evaluate approaches to care delivery, consider treatment gaps, and propose future directions for advancement.

EXPERT OPINION

Since the discovery of the CF gene, CFTR modulators have provided a hallmark of success, even though it was thought not previously possible. This has led to reinvigorated efforts and innovations in treatment approaches and care delivery. Numerous challenges remain because of genetic and phenotypic heterogeneity, access issues, and therapeutic costs, but the collaborative approach between stakeholders for continued innovation fuels optimism. Abbreviations: CF cystic fibrosis; CFF Cystic Fibrosis Foundation (USA); CFTR cystic fibrosis transmembrane regulator; CRISPR clustered regularly interspaced short palindromic repeats; COX cyclo oxygenase; FDA US Food and Drug Administration; FEV1% forced expiratory volume in one second % predicted; F508del deletion of phenylalanine (F) in the 508th position (most common mutation); G551D substitution of the amino acid glycine by aspartate at position 551 in the nucleotide binding domain-1 of the CFTR gene; LMIC low- and middle-income country; LTB4 leukotriene B4; MDT multi-disciplinary care team; NO nitric oxide; NSAIDs non-steroidal anti-inflammatory drugs; SLPI secretory leukocyte protease inhibitor.

Pancreatic complications in children with cystic fibrosis

PURPOSE OF REVIEW

The pancreas is highly affected in cystic fibrosis, with complications occurring early in childhood. This review highlights recent research in exocrine pancreatic function in the era of cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapies and discusses how these are affecting pancreatitis and exocrine pancreatic insufficiency (EPI) in children. Additionally, new research into exocrine--endocrine interactions sheds light on how CFTR dysfunction in ductal cells may affect beta cells.

RECENT FINDINGS

Ivacaftor has disproved the hypothesis that EPI in children with cystic fibrosis is irreversible. Improvements in pancreatic function have increased pancreatitis episodes in some children and reduced them in others. Imaging advances are providing complementary methods for exocrine pancreatic function testing. New research into the interplay between the exocrine and endocrine components of the pancreas are elucidating the intertwined and complex relationship between the exocrine and endocrine pancreas.

SUMMARY

Pancreatic complications contribute to the morbidity and mortality of children with cystic fibrosis. Increasing use of highly effective CFTR modulators will not only abrogate these but will also advance our understanding of pancreatic pathophysiology in cystic fibrosis. New frontiers into pancreatic gene therapy and exocrine--endocrine research will help provide new therapeutic opportunities for pancreatitis, EPI, and diabetes in cystic fibrosis.

[Abdominal manifestations in cystic fibrosis : Clinical review]

Cystic fibrosis (CF) is the most common fatal autosomal recessive disease in the Caucasian population. A mutation in the cystic fibrosis transmembrane regulator protein (CFTR) gene leads to the production of abnormally viscous mucus and secretions in the lungs of these patients. A similar pathology also occurs in other organs. In the abdomen, among others the gastrointestinal tract, the pancreas, and the hepatobiliary system are affected. The involvement of the pancreas leads to its exocrine and endocrine insufficiency. Hepatic manifestations include hepatic steatosis, focal biliary and multilobular cirrhosis, and portal hypertension. Biliary complications include cholelithiasis, microgallbladder, and sclerosing cholangitis. In the gastrointestinal tract, complications such as the distal intestinal obstruction syndrome, invaginations, chronic constipation, wall thickening, and fibrosis in the colon may occur. An important renal manifestation is nephrolithiasis. With currently rapidly increasing life expectancy of patients with cystic fibrosis, complications of extrapulmonary cystic fibrosis manifestations including hepatic and gastrointestinal malignancy could be an increasing cause of morbidity and mortality of these patients. It is therefore important for radiologists to know and recognize these clinical patterns and to monitor these manifestations in follow-up exams. Previous therapy of extrapulmonary manifestations has been largely symptomatic. Fortunately, the new CFTR modulators seem to represent an effective causal therapeutic approach here.

Long-Term Ivacaftor in People Aged 6 Years and Older with Cystic Fibrosis with Ivacaftor-Responsive Mutations

Introduction

Mutations in the cystic fibrosis transmembrane conductance regulator gene (CFTR) affect the quantity and/or function of CFTR protein reaching the cell surface. Ivacaftor, a CFTR potentiator that enhances chloride transport, increases the channel-open probability of normal and dysfunctional CFTR. Initially approved for people with CF (pwCF) with G551D-CFTR gating mutations, ivacaftor demonstrated clinical benefit in pwCF with other gating mutations and certain residual function mutations, including R117H-CFTR, in clinical studies. We evaluated the long-term safety and efficacy of ivacaftor in pwCF aged 6 years and older with non-G551D-CFTR ivacaftor-responsive mutations.

Methods

Efficacy and safety data from a phase 3, multicenter, open-label, extension study for participants from Study 110 (R117H-CFTR mutations), Study 111 (non–G551D-CFTR gating mutations), and Study 113 (n-of-1 pilot study in participants with residual CFTR function) were analyzed. Following washout from the randomized parent study, participants received oral ivacaftor 150 mg once every 12 h for 104 weeks.

Results

Forty-one of 121 participants completed treatment through 104 weeks; 59 participants who did not complete the extension study continued treatment with commercial ivacaftor. The most common adverse events were pulmonary exacerbation (46.3%) and cough (33.9%). Most treatment-emergent adverse events were mild/moderate in severity and consistent with manifestations of CF or the ivacaftor safety profile. Rapid, durable improvement occurred across all efficacy endpoints.

Conclusions

Ivacaftor was generally safe and well tolerated with no new safety concerns for up to 104 weeks in pwCF with ivacaftor-responsive mutations. The pattern of improvement across efficacy endpoints was durable and generally consistent with parent-study outcomes.

Trial Registration

NCT01707290

Electronic supplementary material

The online version of this article (10.1007/s41030-020-00129-2) contains supplementary material, which is available to authorized users.