Ivacaftor improves appearance of sinus disease on computerised tomography in cystic fibrosis patients with G551D mutation

New drugs, new challenges in cystic fibrosis care

Cystic fibrosis (CF) is a genetic disease caused by variants in the gene encoding for the CF transmembrane conductance regulator (CFTR) protein, a chloride and bicarbonate channel. CFTR dysfunction results in a multiorgan disease with the main clinical features being exocrine pancreatic insufficiency and diffuse bronchiectasis with chronic airway infection leading to respiratory failure and premature death. Over the past decades, major progress has been made by implementing multidisciplinary care, including nutritional support, airway clearance techniques and antibiotics in specialised CF centres. The past decade has further seen the progressive development of oral medications, called CFTR modulators, for which around 80% of people with CF are genetically eligible in Europe. CFTR modulators partially restore ion transport and lead to a rapid and major improvement in clinical manifestations and lung function, presumably resulting in longer survival. CFTR modulators have been game-changing in the care of people with CF. However, many questions remain unanswered, such as the long-term effects of CFTR modulators, especially when treatment is started very early in life, or the new CF-related disease emerging due to CFTR modulators. Moreover, severe complications of CF, such as diabetes or cirrhosis, are not reversed on CFTR modulators and around 20% of people with CF bear CFTR variants leading to a CFTR protein that is unresponsive to CFTR modulators. Challenges also arise in adapting CF care to a changing disease. In this review article, we highlight the new questions and challenges emerging from this revolution in CF care.

Pädiatrische Rhinologie

The following review article highlights key topics in pediatric rhinology that are currently the focus in research and at conferences as well as in the interdisciplinary discussion between otorhinolaryngologists and pediatricians. In particular, congenital malformations such as choanal atresia or nasal dermoid cysts are discussed, followed by statements on the current procedures for sinogenic orbital complications as well as on the diagnosis and therapy of chronic rhinosinusitis in children. Furthermore, updates on the role of the ENT specialist in the care for children with cystic fibrosis and primary ciliary dyskinesia are provided.

Chronic rhinosinusitis in the era of CFTR modulator therapy

Chronic rhinosinusitis is a common manifestation of CF that is associated with impaired quality of life and can be difficult to treat. CFTR modulator therapy has resulted in significant improvements in lower respiratory and nutritional outcomes for people with CF however their impact on chronic rhinosinusitis has received less attention. We review the literature in relation to chronic rhinosinusitis in CF and examine the impact of CFTR modulator therapy on symptoms, imaging, endoscopic appearances, and olfactory outcomes in the treatment of chronic rhinosinusitis. While an overall improvement in symptoms, imaging and endoscopic appearances is seen in response to treatment, limited impact is documented on olfaction. Outcome measures employed were heterogenous, limiting comparison of findings. There is a need for well powered prospective real-world studies with standardised outcome measures.

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

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

Upper Airway Disease in Adults with Cystic Fibrosis in the Era of CFTR Modulators

OBJECTIVES

Chronic rhinosinusitis (CRS) is prevalent in people with cystic fibrosis (PwCF) and is often refractory to treatments. Uncontrolled CRS might negatively impact the lower airways and the quality of life. The aim of this study is to evaluate the burden of cystic fibrosis (CF)-related CRS in the era of CF transmembrane conductance regulator (CFTR) modulators.

METHODS

Adult PwCF were asked to fill in a questionnaire on sinonasal complaints, they underwent a nasal endoscopy, bacteriological sampling, and a CT scan. Afterwards, these outcome measures were compared between patients treated with and without modulators.

RESULTS

In the 122 included patients, CRS was present in 83%. CFTR modulators were prescribed in 48% of the patients, with a median of 10 months since the start of the treatment. Subjectively, the median SNOT-22 score was 16/110. Objectively, a median Lund-Kennedy score of 6/12 and modified Lund-Mackay score of 10/24 were observed. No correlation could be found between SNOT-22 score and other outcome measures including endoscopy and radiology. Altogether, 21% of the patients had controlled disease. When comparing patients treated with and without modulators, significantly lower CT scores (p = 0.0018) and less bacterial colonization (p = 0.0082) were observed in patients receiving modulators.

CONCLUSION

CF-CRS is highly prevalent in our cohort and only the minority of PwCF has a well-controlled disease. A multidisciplinary ENT-pneumology clinic would be beneficial, as there is a high discrepancy between patient-reported symptoms and the extent of the disease. CFTR modulators are promising, as lower CT scores and less bacterial colonization were observed in the modulator group.

LEVEL OF EVIDENCE

Level 3 Laryngoscope, 133:2898-2909, 2023.

CFTR Modulators: Current Status and Evolving Knowledge

In the past decade, the medical management of people with cystic fibrosis (pwCF) has changed with the development of small molecules that partially restore the function of the defective CF transmembrane conductance regulator (CFTR) protein and are called CFTR modulators. Ivacaftor (IVA), a CFTR potentiator with a large effect on epithelial ion transport, was the first modulator approved in pwCF carrying gating mutations. Because IVA was unable to restore sufficient CFTR function in pwCF with other mutations, two CFTR correctors (lumacaftor and tezacaftor) were developed and used in combination with IVA in pwCF homozygous for F508del, the most common CFTR variant. However, LUM/IVA and TEZ/IVA were only moderately effective in F508del homozygous pwCF and had no efficacy in those with F508del and minimal function mutations. Elexacaftor, a second-generation corrector, was thus developed and combined to tezacaftor and ivacaftor (ELX/TEZ/IVA) to target pwCF with at least one F508del variant, corresponding to approximately 85% of pwCF. Both IVA and ELX/TEZ/IVA are considered highly effective modulator therapies (HEMTs) in eligible pwCF and are now approved for nearly 90% of the CF population over 6 years of age. HEMTs are responsible for rapid improvement in respiratory manifestations, including improvement in symptoms and lung function, and reduction in the rate of pulmonary exacerbations. The impact of HEMT on extrapulmonary manifestations of CF is less well established, although significant weight gain and improvement in quality of life have been demonstrated. Recent clinical trials and real-world studies suggest that benefits of HEMT could even prove greater when used earlier in life (i.e., in younger children and infants). This article shortly reviews the past 10 years of development and use of CFTR modulators. Effects of HEMT on extrapulmonary manifestations and on CF demographics are also discussed.

Effects of CFTR-modulator triple therapy on sinunasal symptoms in children and adults with cystic fibrosis

PURPOSE

Sinunasal symptoms and chronic rhinusinutitis are common in patients with cystic fibrosis. Cystic fibrosis transmembrane regulator (CFTR) modulators have led to dramatic improvements of respiratory symptoms and quality of life in patients with cystic fibrosis. This study aims to evaluate subjective and objective sinunasal symptoms after start of CFTR-modulator triple therapy.

METHODS

43 patients (n = 6 < 18 years), treated with highly effective CFTR-modulator therapy with elexacaftor-tezacaftor-ivacaftor (ELX/TEZ/IVA) were included, as were 20 controls with cystic fibrosis but without CFTR-modulator therapy (n = 6 < 18 years). All assessed their sinunasal symptoms retrospectively and the intervention group at a mean of 9.3 (2-16) months after start of ELX/TEZ/IVA.

RESULTS

Improvements in SNOT-22 overall score from m = 32.7 to m = 15.7 points (p < 0.0001) as well in the nasal, emotional, otologic, and sleep subdomains could be demonstrated in the intervention group. No changes were found in the control group. Children showed lower SNOT-22 scores than adults and a reduction of SNOT-22 total score from m = 9.4 to m = 2.2 (p = 0.25) was found. 8 patients were evaluated by an otorhinolaryngologist before and after start of ELX/TEZ/IVA and showed pronounced objective clinical improvement.

CONCLUSIONS

Highly effective CFTR-modulator therapy has a significant positive impact on both subjective and objective sinunasal symptoms in patients with CF and some improvement could be demonstrated in children < 18 years as well.

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.

The management of cystic fibrosis chronic rhinosinusitis: An evidenced-based review with recommendations

BACKGROUND

Cystic fibrosis (CF) chronic rhinosinusitis (CRS) has emerged as a distinct diagnostic entity, unique from other endotypes of CRS in its presentation, pathophysiology, diagnosis, treatment, and outcomes. As the sinonasal health of this patient population may have broad effects on pulmonary health and quality of life, a comprehensive understanding of the diagnostic and therapeutic approach to CF CRS is essential. In recognizing recent scientific advances and unique treatment modalities specific to this challenging patient population, in this review we systematically evaluate the scientific literature and provide an evidenced-based review with recommendations (EBRR) for fundamental management principles of CF CRS.

METHODS

A systematic review of the literature was performed. Studies evaluating interventions for the management of CF CRS were included. An iterative review process was implemented in accordance with EBRR guidelines. A treatment recommendation was generated based on an assessment of the benefits, harms, and the overall grade of evidence.

RESULTS

We evaluated the published literature on 5 unique topics. Each of the following therapeutic categories was investigated explicitly for treatment outcomes in patients with CF CRS: (1) nasal saline; (2) intranasal corticosteroids (INCS); (3) topical antibiotics; (4) cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapy; and (5) endoscopic sinus surgery (ESS).

CONCLUSION

Based on the currently available evidence, nasal saline, ESS, and CFTR modulators are recommended in the management of CF CRS when appropriate. INCS and topical antibiotics are options. Clinical judgment and experience are essential in caring for patients with this uniquely challenging disorder.

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.

Sinus Disease Grading on Computed Tomography Before and After Modulating Therapy in Adult Patients with Cystic Fibrosis

Objectives:

Materials and Methods:

Results:

Conclusion:

Chronic rhinosinusitis in cystic fibrosis: a review of therapeutic options

PURPOSE

Chronic rhinosinusitis (CRS) is observed in almost 100% of patients with cystic fibrosis (CF). CF-related CRS treatment is extremely challenging because of the underlying genetic defect leading to its development. CRS in CF is often refractory to standard therapy, while recurrences after surgical treatment are inevitable in the majority of patients. This study provides a precise review of the current knowledge regarding possible therapeutic options for CF-related CRS.

METHODS

The Medline and Web of Science databases were searched without a time limit using the terms "cystic fibrosis" in conjunction with "otorhinolaryngological manifestation", "rhinology" and "sinusitis".

RESULTS

Precise guidelines for CF-induced CRS therapy are lacking due to the lack of large cohort randomized controlled trials. None of the existing therapeutic agents has already been recommended for CRS in CF. Therapy targeting the underlying genetic defect, intranasal dornase alfa administration, and topical delivery of colistin and tobramycin showed promising results in CF-related CRS therapy. Besides the potential effectiveness of nasal steroids, strong recommendations for their usage in CF have not been provided yet. Systemic corticosteroid usage is controversial due to its potential negative influence on pulmonary disease. Ibuprofen revealed some positive effects on CF-related CRS in molecular and small cohort studies. Intranasal irrigation with saline solutions could relieve sinonasal symptoms. Nasal decongestants are not recommended. Endoscopic sinus surgery is the first-line surgical option for refractory CRS. Extensive surgical approaches should be considered as they could improve long-term outcomes in CRS.

CONCLUSION

Further studies are warranted to establish consensus for CF-related CRS therapy.

CFTR Modulator Therapy and Its Impact on Lung Transplantation in Cystic Fibrosis

Cystic fibrosis (CF) is the most common autosomal recessive disorder in Caucasian people and is caused by mutations in the gene encoding for the CF transmembrane conductance regulator (CFTR) protein. It is a multisystem disorder; however, CF lung disease causes most of its morbidity and mortality. Although survival for CF has improved over time due to a multifaceted symptomatic management approach, CF remains a life-limiting disease. For individuals with progressive advanced CF lung disease (ACFLD), lung transplantation is considered the ultimate treatment option if compatible with goals of care. Since 2012, newer drugs, called CFTR modulators, have gradually become available, revolutionizing CF care, as these small-molecule drugs target the underlying defect in CF that causes decreased CFTR protein synthesis, function, or stability. Because of their extremely high efficacy and overall respectable tolerability, CFTR modulator drugs have already proven to have a substantial positive impact on the lives of individuals with CF. Individuals with ACFLD have generally been excluded from initial clinical trials. Now, however, these drugs are being used in clinical practice in selected individuals with ACFLD, showing promising results, although randomized controlled trial data for CFTR modulators in this subgroup of patients are lacking. Such data need to be gathered, ideally in randomized controlled trials including patients with ACFLD. Furthermore, the efficacy and tolerability of the newer modulator therapies in individuals with ACFLD need to be monitored, and their impact on lung disease progression and the need for lung transplantation as the ultimate therapy call for an objective evaluation in larger patient cohorts. As of today, guidelines for referral and listing of lung transplant candidates with CF have not incorporated the status of the new CFTR modulator therapies in the referral and listing process. The purpose of this review article, therefore, is threefold: first, to describe the effects of new therapies, with a focus on the subgroup of individuals with ACFLD; second, to provide an update on the recent outcomes after lung transplantation for individuals with CF; and third, to discuss the referral, evaluation, and timing for lung transplantation as the ultimate therapeutic option in view of the new treatments available in CF.

Prevalence, variability, and predictors of sinus surgery in pediatric patients with cystic fibrosis

INTRODUCTION

Chronic rhinosinusitis is common among individuals with cystic fibrosis (CF) and has an impact on quality of life. Sinus surgery is a treatment option, but minimal literature exists regarding prevalence and indications.

METHODS

Using the linked CF Foundation Patient Registry (CFFPR) - Pediatric Health Information Systems (PHIS) database, we investigated variability in receipt of surgery, predictors of surgery, and time to first surgery. We included individuals less than 18 receiving care between 2006 and 2015 at a CF Foundation care program that is also a PHIS-participating-hospital. We used logistic regression to examine predictors of receipt of surgery and a Kaplan-Meier curve to examine time to first surgery among those born 2005-2007.

RESULTS

There were 11,545 children and adolescents and 2156 (18.7%) received at least one surgery. Variation in number of surgeries was observed across hospitals (median: 63 [IQR, 33-110]). There was an inconsistent pattern between receipt of surgery and markers of disease severity; those receiving surgery having increased odds of treatment use and pulmonary exacerbations and decreased odds of lower lung function and body mass index. Among the cohort of young children, 159 (14%) had at least one surgery with a median age at first surgery of 5.6 (IQR, 3.9-7.0).

CONCLUSIONS

The use of sinus surgery is frequent, but variable, among children and adolescents. Clinical factors are associated with receipt of surgery, but further understanding is needed on other factors that impact variability in use. Our study indicates the need for additional evaluation of the management of CF-related CRS and indications for surgery.

Impact of CFTR Therapy on Chronic Rhinosinusitis and Health Status: Deep Learning CT Analysis and Patient Reported Outcomes

RATIONALE

Elexacaftor/tezacaftor/ivacaftor (ETI) in triple combination improves pulmonary health for people with cystic fibrosis (PwCF) however its impact on objective measures of sinus disease and health utility is unestablished.

OBJECTIVES

To evaluate the impact of ETI on chronic rhinosinusitis (CRS) and general health status incorporating computed tomography (CT), quality-of-life (QOL) and productivity loss.

METHODS

Adult PwCF+CRS with CF transmembrane conductance regulator genotype F508del/F508del or F508del/minimal function who clinically initiated ETI participated in a prospective, observational study. The primary endpoint was change in percent sinus CT opacification (%SO) after 6 months of ETI assessed via deep learning-based methods. Secondary endpoints included changes in sinonasal QOL, health utility value and productivity loss, which were evaluated monthly via validated metrics.

RESULTS

30 PwCF provided baseline data; 25 completed the study. At baseline, the cohort had substantial CRS, with mean 22-question SinoNasal Outcome Test (SNOT-22) score 33.1 and mean sinus CT %SO 63.7%. At 6-month follow-up, %SO improved by mean 22.9% (p<0.001). %SO improvement trended toward greater magnitude for those naïve to prior modulator therapy (p=0.09). Mean SNOT-22 scores and health utility improved by 15.3 and 0.068 [6.8%] (all p<0.007). Presenteeism, activity impairment and overall productivity loss improved (all p<0.049). Improvements in SNOT-22 scores and health utility occurred by one month and remained improved over the study.

CONCLUSIONS

ETI is associated with substantial improvements in sinus CT opacification and productivity loss, and clinically meaningful improvements in sinonasal QOL and health utility. Most improvements were rapid, robust and durable over the study.

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.

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.

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.

Cystic Fibrosis: Emergence of Highly Effective Targeted Therapeutics and Potential Clinical Implications

Cystic fibrosis (CF) remains the most common life-shortening hereditary disease in white populations, with high morbidity and mortality related to chronic airway mucus obstruction, inflammation, infection, and progressive lung damage. In 1989, the discovery that CF is caused by mutations in the CFTR (cystic fibrosis transmembrane conductance regulator) gene that encodes a cAMP-dependent anion channel vital for proper Cl^- and HCO₃^- transport across epithelial surfaces provided a solid foundation for unraveling underlying disease mechanisms and the development of therapeutics targeting the basic defect in people with CF. In this review, we focus on recent advances in our understanding of the molecular defects caused by different classes of CFTR mutations, implications for pharmacological rescue of mutant CFTR, and insights into how CFTR dysfunction impairs key host defense mechanisms, such as mucociliary clearance and bacterial killing in CF airways. Furthermore, we review the path that led to the recent breakthrough in the development of highly effective CFTR-directed therapeutics, now applicable for up to 90% of people with CF who carry responsive CFTR mutations, including those with just a single copy of the most common F508del mutation. Finally, we discuss the remaining challenges and strategies to develop highly effective targeted therapies for all patients and the unprecedented potential of these novel therapies to transform CF from a fatal to a treatable chronic condition.

The impact of ivacaftor on sinonasal pathology in S1251N-mediated cystic fibrosis patients

IMPORTANCE

Sinonasal symptoms in patients suffering from cystic fibrosis can negatively influence the quality of life and sinuses can be a niche for pathogens causing infection and inflammation leading to a decrease of lung function. Ivacaftor, a potentiator of the Cystic Fibrosis Transmembrane Conductance Regulator protein, has shown improvement in pulmonary function in cystic fibrosis patients with different forms of class III gating mutations. However, the effects of ivacaftor on sinonasal pathology have hardly been studied.

OBJECTIVE

To determine the impact of ivacaftor therapy on sinonasal pathology in patients with cystic fibrosis with an S1251N mutation.

DESIGN

Prospective observational mono-center cohort study, between June 2015 and December 2016.

SETTING

A tertiary referral center in Utrecht, The Netherlands.

PARTICIPANTS

Eight patients with cystic fibrosis with an S1251N mutation, treated with the potentiator ivacaftor were investigated.

EXPOSURES

Ivacaftor (Kalydeco, VX-770) therapy. Computed tomography imaging of paranasal sinuses. Nasal nitric oxide concentration measurements and nasal endoscopy.

MAIN OUTCOMES AND MEASURES

Primary outcome is opacification of paranasal sinuses examined with computed tomography scan analysis and scaled by the modified Lund-Mackay score before and one year after treatment. Secondary outcomes are nasal nitric oxide concentration levels, sinonasal symptoms and nasal endoscopic findings before and approximately two months and in some cases one year after treatment.

RESULTS

Computed tomography scan analysis showed a significant decrease in opacification of the majority of paranasal sinuses comparing the opacification score per paranasal sinus before and after one year of treatment with ivacaftor. Median nasal nitric oxide levels significantly improved from 220.00 (IQR:136.00-341.18) to 462.84 (IQR:233.17-636.25) (p = 0.017) parts per billion. Likewise, the majority of sinonasal symptoms and nasal endoscopic pathology decreased or resolved at two months after the use of ivacaftor.

CONCLUSION AND RELEVANCE

Ivacaftor appears to improve sinonasal outcome parameters and thereby sinonasal health in patients with cystic fibrosis with an S1251N mutation.

Chronic rhinosinusitis in patients with cystic fibrosis-Current management and new treatments

OBJECTIVES

The purpose of this article is to provide a state-of-the-art review of the literature and summarize the latest publications on medical and surgical treatment of cystic fibrosis (CF) chronic rhinosinusitis (CRS), with an emphasis on describing recent advancements in cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapies.

METHODS

A comprehensive literature review was conducted utilizing the PubMed database with search phrases detailed within the body of the article. Abstracts were reviewed to include publications detailing medical, surgical, and CFTR modulating therapies for CF CRS. Findings from studies not previously reviewed and publications regarding CFTR modulators were emphasized.

RESULTS

No clear guidelines for treatment of CF CRS are available. Nasal saline rinses, topical steroids, topical antibiotics, and topical dornase alfa are reported medical therapies. Ivacaftor has some sinonasal symptomatic benefit. A new triple therapy CFTR modulator, elexacaftor/tezacaftor/ivacaftor, is capable of treating 90% of patients with CF and has shown the greatest FEV1 improvement of any CFTR modulator yet. There is no clear consensus on surgical indications or technique, though aggressive surgery in recalcitrant disease has shown some symptomatic benefit. Endoscopic sinus surgery after lung transplantation may benefit some patients in whom the sinuses serve as a reservoir for recurrent pulmonary infections by decreasing rates of bronchiolitis obliterans syndrome and improving 5 year survival.

CONCLUSION

As lifespan increases for patients with CF, further investigation into medical therapy, CFTR modulator sinonasal outcomes, and surgical technique and outcomes for CF CRS is needed.

LEVEL OF EVIDENCE

5.

Cystic Fibrosis Transmembrane Conductance Regulator Modulator Therapy: A Review for the Otolaryngologist

Background

Cystic fibrosis (CF) is a genetic disease that may result in multiple systemic disorders and potentially fatal severe respiratory compromise. However, the advent of CF transmembrane conductance regulator (CFTR) modulators has changed the management of CF for patients with select mutations. Although clinical trials have highlighted increased pulmonary function and decreased exacerbations as a result of these novel therapies, their effect on the sinuses has not been well-described.

Objective

Our objective is to review the CFTR modulators to provide otolaryngologists, physicians who frequently care for patients with CF, a basic understanding of these drugs and their effects on chronic rhinosinusitis (CRS) in patients with CF.

Methods

The clinically approved and available CFTR modulators and specific indications for their use are reviewed. Additionally, a systematic review of these therapies and effects on CRS in CF was performed.

Results

Four Food and Drug Administration approved CFTR modulators are available for patients with CF. Current drugs are approved for gating, residual function, or F508del mutations. Multiple reports describe CFTR modulators’ increase in transepithelial ion transport in nasal epithelial cultures; however, clinical studies regarding effects of these modulators on sinonasal health are limited to 5 studies that present new data of the effects of CFTR modulators in CRS.

Conclusions

CFTR modulators have changed management of CF. Initial studies of these medications demonstrate promising results in CF; however, there is a paucity of literature describing the effect of CFTR modulators on CF-associated CRS, although initial results are encouraging.

Precision medicine in united airways disease: A "treatable traits" approach

United airways disease (UAD) is the concept that the upper and lower airways, which are anatomically and immunologically related, form a single organ. According to this concept, upper and lower airway diseases are frequently comorbid because they reflect manifestations of a single underlying disease at different sites of the respiratory tract. Allergic asthma-allergic rhinitis is the archetypal UAD, but emerging data indicate that UAD is a heterogeneous condition and consists of multiple phenotypes (observable clinical characteristics) and endotypes (pathobiologic mechanisms). The UAD paradigm also extends to myriad sinonasal diseases (eg, chronic rhinosinusitis with or without nasal polyps) and lower airway diseases (eg, bronchiectasis, chronic obstructive pulmonary disease). Here, we review currently known phenoendotypes of UAD and propose a "treatable traits" approach for the classification and management of UAD, wherein pathophysiological mechanisms and factors contributing to disease are identified and targeted for treatment. Treatable traits in UAD can be analyzed according to a framework comprising airway inflammation (eosinophilic, neutrophilic), impaired airway mucosal defense (impaired mucociliary clearance, antibody deficiency), and exogenous cofactors (allergic sensitizers, tobacco smoke, microbes). Appreciation of treatable traits is necessary in advancing the effort to deliver precise treatments and achieve better outcomes in patients with UAD.

[Ageing with cystic fibrosis: Classical and emerging comorbidities in adults with cystic fibrosis]

Cystic fibrosis (CF) is a genetic disease with pulmonary involvement being predominant and often leading to respiratory failure and premature death. Non-pulmonary complications related to CF transmembrane conductance regulator (CFTR) defect are numerous and account for significant morbidity (exocrine pancreatic insufficiency, diabetes, CF-related liver disease, chronic sinusitis, osteoporosis). Improvement in patients' care led to a continuous increase in life expectancy, with a subsequent increase in the number of adult CF patients worldwide. Increased life expectancy comes with increased prevalence of CF-related comorbidities, but also with new emerging complications directly related to ageing (chronic kidney disease, cardiovascular risk factors, cancers). CFTR modulators might also contribute to modify the face of CF epidemiology and prognosis. Ageing with CF has become a challenge for CF patients and caregivers. This review summarizes classic and emerging comorbidities in the context of current growth and ageing of the CF population. It also addresses potential roles of CFTR modulators.

CFTR modulator therapy in patients with cystic fibrosis and an organ transplant

CFTR modulators are a class of drugs which directly target the defective CFTR protein in cystic fibrosis (CF), improving its function with resultant clinical improvements. Currently these drugs are confined to people with a limited selection of genetic mutations. New modulators are in development which will lead to the majority of patients with CF becoming eligible for treatment. CFTR modulators are currently considered contraindicated in patients with a solid organ transplant. This excludes many patients who may benefit from the multisystem effects of CFTR modulator treatment. In this review, we discuss issues regarding drug interactions, organ transplantation and CFTR modulation.

The treatment of the pulmonary and extrapulmonary manifestations of cystic fibrosis

Cystic fibrosis (CF) is a complex multisystem disease with considerable between patient variability in its manifestations and severity. In the past several decades, the range of treatments and the evidence to support their use for the pulmonary and extrapulmonary manifestations of CF have increased dramatically, contributing to the improved median survival of patients. As therapy for CF has evolved, new challenges including treatment adherence, medication intolerance and allergy, medical complications and coping with the burden of disease in the context of having a family and managing employment have arisen. While the majority of current therapy focuses primarily on improving symptoms, new therapies (CFTR modulators) target the underlying genetic defect.

Current and emerging comorbidities in cystic fibrosis

Cystic fibrosis transmembrane conductance regulator (CFTR) is expressed ubiquitously throughout the body. Thus, while respiratory manifestations dominate much of cystic fibrosis (CF) care, there are prominent multi-organ manifestations and comorbidities. In the general population, the number of comorbidities increases with aging. Few illnesses have experienced such a dramatic improvement in survival as CF, which has been transformed from an illness of childhood death to one of adult survival. Hence, as longevity increases in CF, it is paralleled by an increasing number of patients with multicomplex comorbidities availing of care from adult CF multi-disciplinary teams. This review gives an overview of the traditional CF associated comorbidities and those emerging in an aging adult cohort. While historically the treatment of CF focused on the consequences of CFTR dysfunction, the recent advent of CFTR modulators with the potential to enhance CFTR function represents an opportunity to potentially reverse or delay the development of some of the comorbidities associated with CF. Where evidence is available for the impact of CFTR modulatory therapy, namely ivacaftor on comorbidities in CF, this is highlighted.

The effects of ivacaftor on CF fatty acid metabolism: An analysis from the GOAL study

BACKGROUND

Ivacaftor has produced significant improvement in certain individuals with cystic fibrosis (CF), though the full metabolic effects of treatment remain unknown. Abnormalities in fatty acid metabolism have previously been shown to be a characteristic of CFTR dysfunction. We hypothesized that as a reflection of this clinical improvement, ivacaftor would improve plasma fatty acid levels and decrease urine prostaglandin E metabolite levels.

METHODS

This study analyzed plasma fatty acid levels and urine prostaglandin E metabolites (PGE-M) in 40 subjects with CF participating in the G551D observational (GOAL) study who demonstrated response to the medication by a significant decrease in sweat Cl levels. Paired samples were analyzed before and after 6months of ivacaftor treatment.

RESULTS

Linoleic acid and docosahexaenoic acid levels, which are typically low in individuals with CF, did not significantly increase with ivacaftor treatment. However, arachidonic acid levels did decrease with ivacaftor treatment and there was a significant decrease in the arachidonic acid metabolite PGE-M as measured in the urine [median: before treatment 17.03ng/mg Cr; after treatment 9.06ng/mg Cr; p<0.001]. Furthermore, there were fatty acid age differences observed, including pediatric participants having significantly greater linoleic acid levels at baseline.

CONCLUSION

Ivacaftor reduces inflammatory PGE without fully correcting the plasma fatty acid abnormalities of CF. Age-related differences in fatty acid levels were observed, that may be a result of other clinical factors, such as diet, clinical care, or drug response.

CFTR Modulator Therapies in Pediatric Cystic Fibrosis: Focus on Ivacaftor

INTRODUCTION

Mutations in the cystic fibrosis transmembrane conductance regulator protein (CFTR) cause cystic fibrosis (CF), a disease with life threatening pulmonary and gastrointestinal manifestations. Recent breakthrough therapies restore function to select disease-causing CFTR mutations. Ivacaftor is a small molecule that increases the open channel probability of certain CFTR mutations, producing clear evidence of bioactivity and efficacy in pediatric CF patients. CFTR modulators represent a significant advancement in CF treatment. Extending these therapies to young CF patients is proposed to have the greatest long term impact, potentially preventing later disease.

AREAS COVERED

Here we summarize the research experience of CFTR modulators in pediatrics, focusing on ivacaftor and highlighting challenges in pediatric studies. As a result of these studies, ivacaftor has been approved in CF patients age 2 years and older who have one of ten CFTR mutations.

EXPERT OPINION

Conducting studies in young CF patients presents unique challenges, including small numbers of patients and difficulty selecting sensitive biomarkers and meaningful outcome measures. Adverse events may be more pronounced in children and deserve special attention. Ongoing efforts must focus on expanding and validating new biomarkers, innovative study design, and thorough monitoring of adverse events in children treated with CFTR modulators.

New and emerging targeted therapies for cystic fibrosis

Cystic fibrosis (CF) is a monogenic autosomal recessive disorder that affects about 70,000 people worldwide. The clinical manifestations of the disease are caused by defects in the cystic fibrosis transmembrane conductance regulator (CFTR) protein. The discovery of the CFTR gene in 1989 has led to a sophisticated understanding of how thousands of mutations in the CFTR gene affect the structure and function of the CFTR protein. Much progress has been made over the past decade with the development of orally bioavailable small molecule drugs that target defective CFTR proteins caused by specific mutations. Furthermore, there is considerable optimism about the prospect of gene replacement or editing therapies to correct all mutations in cystic fibrosis. The recent approvals of ivacaftor and lumacaftor represent the genesis of a new era of precision medicine in the treatment of this condition. These drugs are having a positive impact on the lives of people with cystic fibrosis and are potentially disease modifying. This review provides an update on advances in our understanding of the structure and function of the CFTR, with a focus on state of the art targeted drugs that are in development.

Cystic Fibrosis and Its Management Through Established and Emerging Therapies

Cystic fibrosis (CF) is the most common life-shortening autosomal recessive disorder in the Caucasian population and occurs in many other ethnicities worldwide. The daily treatment burden is substantial for CF patients even when they are well, with numerous pharmacologic and physical therapies targeting lung disease requiring the greatest time commitment. CF treatments continue to advance with greater understanding of factors influencing long-term morbidity and mortality. In recent years, in-depth understanding of genetic and protein structure-function relationships has led to the introduction of targeted therapies for patients with specific CF genotypes. With these advances, CF has become a model of personalized or precision medicine. The near future will see greater access to targeted therapies for most patients carrying common mutations, which will mandate individualized bench-to-bedside methodologies for those with rare genotypes.

CFTR Modulator Therapies for Cystic Fibrosis

The cloning of cystic fibrosis transmembrane conductance regulator (CFTR) set into motion a cascade of discoveries that have helped to reveal the underlying pathophysiologic basis of cystic fibrosis (CF). This discovery and the knowledge that followed have also provided the opportunity to target this basic defect, with the hope of reversing or preventing the serious clinical consequences that result from absent CFTR function. With the recent approval of 2 therapies that directly modulate CFTR function in more than half of the CF population, we are now at the beginning of a pathway to providing increasingly effective therapies that have the potential to provide a fundamental change in the outcome of most patients with CF.