Disease progression in patients with cystic fibrosis treated with ivacaftor: Data from national US and UK registries

Long-term impact of ivacaftor on mortality rate and health outcomes in people with cystic fibrosis

BACKGROUND

Ivacaftor (IVA) has been shown to improve lung function and other clinical outcomes in people with cystic fibrosis (CF). A decade of real-world IVA availability has enabled the examination of long-term outcomes with this treatment. This retrospective, longitudinal cohort study investigated the impact of IVA on mortality rate and health outcomes among people with CF in the US.

METHODS

Data from the US CF Foundation Patient Registry from January 2010 to December 2019 were analysed. The IVA-treated cohort included people with a CF transmembrane conductance regulator (CFTR) gating mutation (excluding R117H); age-matched comparator cohort included people with a F508del and a minimal function CFTR mutation who had no prior CFTR modulator treatment. Baseline characteristics were balanced between cohorts using standardised mortality ratio weighting generated from propensity scores. Outcomes of interest were overall survival, lung transplant, percent predicted forced expiratory volume in 1 s (ppFEV1), body mass index (BMI), pulmonary exacerbations (PEx), outpatient visits and hospitalisations.

FINDINGS

Over a maximum follow-up of 7.9 years, the IVA-treated cohort (N=736) had lower rates of mortality (hazard ratio [HR] (95% CI): 0.22 (0.09 to 0.45)), lung transplant (HR: 0.11 (95% CI 0.02 to 0.28)), PEx (rate ratio: 0.49 (95% CI 0.42 to 0.55)) and all-cause hospitalisations (rate ratio: 0.50 (95% CI 0.43 to 0.56)) as well as better lung function (mean difference in ppFEV1: 8.46 (95% CI 7.34 to 9.75)) and higher BMI/BMI z-scores (mean difference 1.20 (95% CI 0.92 to 1.71) kg/m2 and 0.27 (95% CI 0.25 to 0.40), respectively) than the comparator cohort (N=733).

INTERPRETATION

Our analysis suggests that IVA provides sustained clinical benefits in people with CF over a follow-up period of approximately 8 years. These findings reinforce the existing real-world evidence that IVA can slow disease progression and decrease the healthcare burden of CF over the long term.

Mental health, sleep, and respiratory health after initiating elexacaftor/tezacaftor/ivacaftor treatment in children with cystic fibrosis

INTRODUCTION

Cystic fibrosis transmembrane conductance regulator (CFTR) modulator elexacaftor/tezacaftor/ivacaftor (ETI) significantly improves lung function but its effect on mental health and sleep remains poorly understood. We report on mental health, sleep, and respiratory health outcomes of adolescents with CF commenced on ETI therapy, and monitored the prevalence of neuropsychiatric issues through the coronavirus disease 2019 pandemic.

METHODS

We conducted a prospective longitudinal study of 31 adolescents (aged 10-18 years) from July 2021 to October 2022. Data collected include demographics, Patient Health Questionnaire-9 (PHQ-9), General Anxiety Disorder-7 (GAD-7), Pediatric Daytime Sleepiness Scale (PDSS), Sleep Disturbance Scale for Children (SDSC) scores, and FEV1 percent predicted. Twenty of 31 adolescents had data before and after ETI initiation. Mean differences (MD) in mental health, sleep, and respiratory health pre- and post-ETI therapy commencement were estimated using paired t-tests. The prevalence and trajectories of anxiety, depression, and sleep disturbance were described between the ETI epochs, and over the pandemic period.

RESULTS

FEV1 improved following ETI therapy commencement (MD, 95% confidence interval [CI]: 7.1% (4.7%-9.6%) whereas PHQ-9, GAD-7, PDSS, and SDSC scores did not change significantly. Ten percent of participants developed new-onset anxiety/depression concerns and 10% developed new sleep concerns following ETI initiation.

CONCLUSION

This is the first prospective longitudinal study of mental health and sleep changes after ETI commencement in adolescents with CF. Although respiratory outcomes improved, ETI did not improve anxiety, depression or sleep.

Sex Differences Persist After Treatment With Ivacaftor in People With Cystic Fibrosis

BACKGROUND

Historically, studies show that female patients with cystic fibrosis (CF) have worse pulmonary outcomes than male patients, including decreased life expectancy. It is unknown whether this disparity persists in the new era of highly effective modulator therapies. Ivacaftor has been available in the United States for > 10 years, allowing for the opportunity to understand the impact this therapy may have on sex disparities in CF. We hypothesized that female patients will continue to show worse outcomes because we suspect that the disparity is not driven solely by ion channel dysfunction.

RESEARCH QUESTION

Does a difference in outcomes between male and female patients persist after the initiation of ivacaftor in people with CF?

STUDY DESIGN AND METHODS

We conducted a retrospective cohort study using the CF Foundation Patient Registry comparing changes in pulmonary exacerbation rate, lung function (FEV1 % predicted), and presence of Pseudomonas aeruginosa among male patients vs female patients before and after initiation of treatment with the highly effective modulator ivacaftor.

RESULTS

The cohort comprised 1,900 people with CF who were treated with ivacaftor between 2010 and 2017; 928 patients (48.84%) were male and 972 patients (51.16%) were female with a mean age of 33.09 years. Male patients showed a significant decrease in pulmonary exacerbations after ivacaftor treatment (from 0.38 to 0.34; adjusted rate ratio, 0.89; P = .028), whereas female patients did not (from 0.48 to 0.45; adjusted rate ratio, 0.95; P = .174). FEV1 % predicted similarly decreased in both male and female patients before vs after ivacaftor treatment. P aeruginosa prevalence decreased to a similar extent in both male and female patients after ivacaftor treatment.

INTERPRETATION

Our findings demonstrate that sex disparities in CF persist in those treated with ivacaftor because of differences in pulmonary exacerbations. More research is needed to determine the specific pathophysiologic drivers of this disparity.

Evolution of nutritional management in children with cystic fibrosis - a narrative review

Nutrition has played a central role in the management and outcomes of people with cystic fibrosis (pwCF) since the 1970s. Advances in therapies and practices in recent decades have led to a significant change in the patient landscape with dramatic improvements in life expectancy, as well as quality of life, bringing with it new issues. Historically, cystic fibrosis was a condition associated with childhood and malnutrition; however, changes in patient demographics, nutritional assessment and fundamental nutritional management have evolved, and it has become an increasingly prevalent adult disease with new nutritional challenges, including obesity. This paper aims to describe these changes and the impact and challenges they bring for those working in this field. Nutritional professionals will need to evolve, adapt and remain agile to the wider range of situations and support required for a new generation of pwCF. Specialised nutrition support will continue to be required, and it will be additionally important to improve and optimise quality of life and long-term health.

The Changing Landscape of Treatment for Cystic Fibrosis Related Diabetes

Objective

Patients with Cystic Fibrosis related diabetes [CFRD] are treated with insulin and high calorie diets to maintain body mass. The combined CFTR modulator elexacaftor/tezacaftor/ivacaftor [ETI] decreases pulmonary exacerbations and improves nutritional status. We reviewed the effects of ETI on BMI, HbA1c and diabetes regimen in patients with CFRD over a period of three years.

Methods

Data of previously CFTR-modulator-naïve patients with CFRD and pancreatic insufficiency on ETI therapy were retrieved from an electronic health record database. Patients were followed for a mean duration of 2.7 ± 0.8 years after ETI initiation. Data pertaining to weight, BMI, HbA1c and diabetes regimen were collected at 6 months, 12 months, 2 years and at 3 years post-ETI initiation. Patients were then dichotomized based on their baseline BMI into a low BMI group and an "at target" BMI group. The effects of ETI on changes in weight, BMI, A1c and diabetes regimen were compared in both groups over a period of three years.

Results

Twenty-seven patients with CFRD (15 men/12 women), age 30.6 ± 11.5 (SD) years, BMI 22.4 ± 4.0 kg/m2, were included. Fifteen patients had low BMI (<22 kg/m2 for women, <23 kg/m2 for men) and 12 patients had at target BMI (≥22 kg/m2for women, ≥BMI 23 kg/m2 for men). Patients with low BMI had an increase in their BMI from 19.5 ± 1.7 to 21.4 ± 2.2 kg/m2 at one year (p = 0.002), and 21.8 ± 1.8 kg/m2 at three years (p = 0.004) after ETI initiation. Four patients (out of 15) in the low BMI group had achieved normal BMI by the end of study follow up. There was no change in weight in the at target BMI group. HbA1c and basal insulin requirements did not change in either group. Five patients started non-insulin therapies.

Conclusion

BMI increased after ETI therapy in CFRD patients with low BMI, but not in those with at target BMI. The use of non-insulin therapies is increasing in CFRD and should be evaluated in future studies.

Longitudinal changes in habitual physical activity in adult people with cystic fibrosis in the presence or absence of treatment with elexacaftor/tezacaftor/ivacaftor

Background

Habitual physical activity (PA) and exercise training are accepted as important aspects of care for people with cystic fibrosis (pwCF) to improve health-related measures of physical fitness, which in turn have a positive impact on quality of life and prognosis. In the last decade, effective CFTR modulator therapies have become a promising treatment for pwCF by targeting the underlying cause of CF. This highly effective therapy improves clinical outcomes and quality of life in people with specific CFTR mutations. Little is known about the longitudinal pattern of PA or the impact of the highly effective modulator therapy with Elexacaftor/Tezacaftor/Ivacaftor (ETI) on PA in adult pwCF. This study assessed the course of device-based PA measurement in adult pwCF and evaluated the effects of ETI on habitual physical activity in those who were eligible for ETI.

Methods

Data from adult pwCF (aged ≥18 years) were analysed at baseline and follow-up, using identical assessments at both time points. Outcome parameters were PA in steps/day and the intensity of PA. The group that received ETI was treated for an average of 33 weeks and not for the entire duration of the period. The data were collected between 2021 and 2022, following the removal of absolute pandemic restrictions/lockdowns.

Results

Follow-up duration was 5.6 years in pwCF with ETI (ETI group, n = 21) and 6.5 years in pwCF without ETI (non-ETI group, n = 6). From baseline to follow-up, pwCF treated with ETI had a significant increase in steps/day (+25%, p = 0.019) and a non-significant increase in moderate-to-vigorous intensity time (+5.6%, p = 0.352). Conversely, individuals in the non-ETI group showed a non-significant decrease in both steps/day -3.2%, p = 0.893) and moderate-to-vigorous intensity time (-25%, p = 0.207). The ETI group showed a significant decrease in percent predicted forced expiratory volume in 1 s (ppFEV1) and FEV1 z-score before the start of ETI treatment, both of which improved significantly after therapy initiation. Body weight and body mass index also improved significantly with ETI use.

Conclusions

These data suggest that ETI treatment has a positive effect on habitual physical activity behavior in the adult pwCF studied.

CFTR is required for zinc-mediated antibacterial defense in human macrophages

Cystic fibrosis transmembrane conductance regulator (CFTR) is an anion transporter required for epithelial homeostasis in the lung and other organs, with CFTR mutations leading to the autosomal recessive genetic disease CF. Apart from excessive mucus accumulation and dysregulated inflammation in the airways, people with CF (pwCF) exhibit defective innate immune responses and are susceptible to bacterial respiratory pathogens such as Pseudomonas aeruginosa. Here, we investigated the role of CFTR in macrophage antimicrobial responses, including the zinc toxicity response that is used by these innate immune cells against intracellular bacteria. Using both pharmacological approaches, as well as cells derived from pwCF, we show that CFTR is required for uptake and clearance of pathogenic Escherichia coli by CSF-1-derived primary human macrophages. CFTR was also required for E. coli-induced zinc accumulation and zinc vesicle formation in these cells, and E. coli residing in macrophages exhibited reduced zinc stress in the absence of CFTR function. Accordingly, CFTR was essential for reducing the intramacrophage survival of a zinc-sensitive E. coli mutant compared to wild-type E. coli. Ectopic expression of the zinc transporter SLC30A1 or treatment with exogenous zinc was sufficient to restore antimicrobial responses against E. coli in human macrophages. Zinc supplementation also restored bacterial killing in GM-CSF-derived primary human macrophages responding to P. aeruginosa, used as an in vitro macrophage model relevant to CF. Thus, restoration of the zinc toxicity response could be pursued as a therapeutic strategy to restore innate immune function and effective host defense in pwCF.

ESPEN-ESPGHAN-ECFS guideline on nutrition care for cystic fibrosis

BACKGROUND

Nutritional status is paramount in Cystic Fibrosis (CF) and is directly correlated with morbidity and mortality. The first ESPEN-ESPGHAN-ECFS guidelines on nutrition care for infants, children, and adults with CF were published in 2016. An update to these guidelines is presented.

METHODS

The study was developed by an international multidisciplinary working group in accordance with officially accepted standards. Literature since 2016 was reviewed, PICO questions were discussed and the GRADE system was utilized. Statements were discussed and submitted for on-line voting by the Working Group and by all ESPEN members.

RESULTS

The Working Group updated the nutritional guidelines including assessment and management at all ages. Supplementation of vitamins and pancreatic enzymes remains largely the same. There are expanded chapters on pregnancy, CF-related liver disease, and CF-related diabetes, bone disease, nutritional and mineral supplements, and probiotics. There are new chapters on nutrition with highly effective modulator therapies and nutrition after organ transplantation.

Eradication of Nontuberculous Mycobacteria in People with Cystic Fibrosis Treated with Elexacaftor/Tezacaftor/Ivacaftor: A Multicenter Cohort Study

BACKGROUND

The prevalence of nontuberculous mycobacteria (NTM) infections is rising in people with cystic fibrosis (pwCF). NTM infection, especially infection with Mycobacterium abscessus complex (MABC), is commonly associated with severe lung deterioration. The current treatment modalities, including multiple intravenous antibiotics, frequently fail to achieve airway eradication. Although treatment with elexacaftor/tezacaftor/ivacaftor (ETI) has been shown to modulate the lung microbiome, data regarding its role in eradicating NTM in pwCF is lacking. Our aim was to evaluate the impact of ETI on the rate of NTM eradication in pwCF.

METHODS

This retrospective multicenter cohort study included pwCF from five CF centers in Israel. PwCF aged older than 6 who had at least one positive NTM airway culture in the past two years and were treated with ETI for at least one year were included. The annual NTM and bacterial isolations, pulmonary function tests, and body mass index were analyzed before and after ETI treatment.

RESULTS

Fifteen pwCF were included (median age 20.9 years, 73.3% females, 80% pancreatic insufficient). In nine patients (66%) NTM isolations were eradicated following treatment with ETI. Seven of them had MABC. The median time between the first NTM isolation and treatment with ETI was 2.71 years (0.27-10.35 years). Eradication of NTM was associated with improved pulmonary function tests (p<0.05).

CONCLUSIONS

For the first time, we report successful eradication of NTM, including MABC, following treatment with ETI in pwCF. Additional studies are needed to assess whether treatment with ETI can result in the long-term eradication of NTM.

Decline in HbA1c during the first year of elexacaftor/tezacaftor/ivacaftor treatment in the Danish cystic fibrosis cohort: Short title: Decline in HbA1c after elexacaftor/tezacaftor/ivacaftor treatment

BACKGROUND

Elexacaftor/tezacaftor/ivacaftor (ETI) has improved the clinical status of individuals with cystic fibrosis (CF), however, whether ETI impacts glucose tolerance remains unknown. We aimed to study the change in glycated hemoglobin (HbA1c) and CF related diabetes (CFRD) status after initiation of ETI.

METHODS

We included individuals ≥12 years treated with ETI in Denmark in a longitudinal observational study. HbA1c was measured at baseline, 3, 6, 9 and 12 months after treatment initiation. Change in HbA1c was assessed in mixed models adjusted for age, sex, glucose tolerance and prior CFTR modulator treatment. In a sub-population with CFRD, we assessed the change in insulin usage, hypoglycemic events and the 30-day continuous glucose monitoring (CGM) parameters (i.e., average blood glucose, time below (≤3.9 mM) and above (>10.0 mM) normal range, and the variation in glucose) after 12 months of treatment.

RESULTS

Among 321 individuals with CF, HbA1c declined by 2.1 mmol/mol [95 % confidence interval (CI): -2.6; -1.5 mmol/mol] after 3 months and by 2.3 mmol/mol [95 %CI: -2.8; -1.9 mmol/mol] after 12 months of ETI treatment. The decline was independent of glucose tolerance status at baseline. In 26 individuals with CFRD at baseline, the mean decline in HbA1c was 3.6 mmol/mol [95 %CI: -6.9; -0.4 mmol/mol] after 12 months, but we did not observe any change in insulin usage, weekly number of hypoglycemic events or CGM parameters.

CONCLUSION

In the Danish CF cohort, HbA1c declined over 12 months of ETI treatment, however, among a subset with CFRD, we observed no change in insulin usage and CGM glucose levels.

Olfaction, body mass index, and quality of life with cystic fibrosis combination therapy

BACKGROUND

Triple-combination therapy of elexacaftor-tezacaftor-ivacaftor (ETI) has been shown to reduce morbidity and mortality in people with cystic fibrosis (PwCF). Although patient body mass index (BMI) favorably increases with ETI treatment, factors contributing to this improvement are poorly characterized. Olfaction contributes to appetite stimulation and anticipation of eating, where higher rates of olfactory impairment (OI) in PwCF may contribute to malnutrition and BMI instability in this population.

METHODS

The authors performed a prospective cohort study analyzing 41 CF patient responses to the Cystic Fibrosis Questionnaire-Revised (CFQR) and the 22-Item Sino-Nasal Outcome Test (SNOT-22) and used generalized estimating equations to understand the change in survey variables from being untreated (baseline) to undergoing 3 months of ETI therapy (follow-up).

RESULTS

Patients reported significant improvement in their sense of smell at follow-up (p = 0.0036). Their improvements in sense of smell were not confounded by changes in rhinologic or extranasal rhinologic symptoms. Self-reported quality of life (QoL) improved after 3 months of ETI therapy (p = < 0.0001) as did BMI (p = < 0.0001), but improved sense of smell did not independently mediate these changes in QoL and BMI.

CONCLUSION

Our results support the impression that ETI therapy improves CF-associated rhinologic symptoms and reverses OI, while contributing to improvement in rhinologic QoL. Sense of smell is not an independent mediator of improved QoL and BMI in this population, suggesting that other factors may have a stronger role in these realms. However, given the subjective improvement in sense of smell, additional evaluation of OI using psychophysical chemosensory assessment will clarify the connection between olfaction, BMI, and QoL in PwCF.

An Update in Cystic Fibrosis-Related Diabetes in Children and Adolescents

This paper delineates several aspects of cystic fibrosis-related diabetes (CFRD)-a common complication of cystic fibrosis (CF). CFRD exhibits a predilection for older individuals with CF, yet it also extends its influence on children and adolescents. Scientific insights postulate a potential link between CFRD and the aberrant mucus production within the pancreas, thereby culminating in pancreatic insufficiency. This, in turn, perturbs the synthesis of insulin, a pivotal endocrine hormone responsible for the regulation of glycemic levels. Standardized protocols advocate for the systematic screening of CFRD among all individuals with CF, commencing at the age of 10 years using the oral glucose tolerance test (OGTT). Therapeutic modalities encompass insulin therapy, dietary adjustments, and the vigilant monitoring of glycemic parameters. The overarching objective is to maintain blood glucose levels within a targeted range to mitigate the advent of diabetic complications. Untreated or sub-optimally managed CFRD can precipitate a spectrum of deleterious health ramifications, encompassing cardiovascular afflictions, neuropathy, renal dysfunction, and ocular complications.

Pancreas and islet morphology in cystic fibrosis: clues to the etiology of cystic fibrosis-related diabetes

Cystic fibrosis (CF) is a multi-organ disease caused by loss-of-function mutations in CFTR (which encodes the CF transmembrane conductance regulator ion channel). Cystic fibrosis related diabetes (CFRD) occurs in 40-50% of adults with CF and is associated with significantly increased morbidity and mortality. CFRD arises from insufficient insulin release from β cells in the pancreatic islet, but the mechanisms underlying the loss of β cell function remain understudied. Widespread pathological changes in the CF pancreas provide clues to these mechanisms. The exocrine pancreas is the epicenter of pancreas pathology in CF, with ductal pathology being the initiating event. Loss of CFTR function results in ductal plugging and subsequent obliteration. This in turn leads to destruction of acinar cells, fibrosis and fatty replacement. Despite this adverse environment, islets remain relatively well preserved. However, islet composition and arrangement are abnormal, including a modest decrease in β cells and an increase in α, δ and γ cell abundance. The small amount of available data suggest that substantial loss of pancreatic/islet microvasculature, autonomic nerve fibers and intra-islet macrophages occur. Conversely, T-cell infiltration is increased and, in CFRD, islet amyloid deposition is a frequent occurrence. Together, these pathological changes clearly demonstrate that CF is a disease of the pancreas/islet microenvironment. Any or all of these changes are likely to have a dramatic effect on the β cell, which relies on positive signals from all of these neighboring cell types for its normal function and survival. A thorough characterization of the CF pancreas microenvironment is needed to develop better therapies to treat, and ultimately prevent CFRD.

Effects of modulator therapies on endocrine complications in adults with cystic fibrosis: a narrative review

Cystic fibrosis is a monogenic disorder caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) protein, which transports chloride ions in secretory organs. Modulator therapies are small molecules that correct CFTR dysfunction and can lead to a wide range of benefits for both pulmonary and extrapulmonary complications of cystic fibrosis. With advancements in airway, antimicrobial and nutritional therapies and now introduction of modulator therapies, most people living with cystic fibrosis in Australia are now adults. For adults with cystic fibrosis, endocrine manifestations such as cystic fibrosis-related diabetes, metabolic bone disease, and reproductive health are becoming increasingly important, and emerging evidence on the endocrine effects of CFTR modulator therapies is promising and is shifting paradigms in our understanding and management of these conditions. The management of cystic fibrosis-related diabetes will likely need to pivot for high responders to modulator therapy with dietary adaptions and potential use of medications traditionally reserved for adults with type 2 diabetes, but evidence to support changing clinical care needs is currently lacking. Increased attention to diabetes-related complications screening will also be required. Increased exercise capacity due to improved lung function, nutrition and potentially direct modulator effect may have a positive impact on cystic fibrosis-related bone disease, but supporting evidence to date is limited. Fertility can improve in women with cystic fibrosis taking modulator therapy. This has important implications for pregnancy and lactation, but evidence is lacking to guide pre-conception and antenatal management. Provision of multidisciplinary clinical care remains ever-important to ensure the emergence of endocrine and metabolic complications are optimised in adults with cystic fibrosis.

Advances in cystic fibrosis-related diabetes: Current status and future directions

AIMS

The aim of this review is to give an update of the recent advances in the pathophysiology, prognosis, diagnosis and treatments of cystic fibrosis-related diabetes (CFRD).

METHODS

The literature survey focuses on original and review articles dealing with CFRD between 2006 and 2023, and in particular with: pathophysiology, risk and predictive factors, screening, chronic complications of CFRD, management and the effects of CFTR channel modulator therapies on glucose homeostasis, using PubMed®.

RESULTS

The rising prevalence of CFRD is due to prolonged life survival among patients with cystic fibrosis (CF). Advances in the understanding of the pathophysiology highlight the singularity of CFRD. Adherence to diagnostic guidelines remains challenging. Besides the classical OGTT, alternative diagnostic tests are being considered: HbA1c measurement, continuous glucose monitoring (CGM), intermediate measurements of alternative glucose tolerance stages through OGTT and homeostatic model assessment (HOMA). Early treatment of (pre)diabetes in CF patients is mandatory. The advent of CFTR channel modulator therapies have created a paradigm shift in the management of CF: they seem to improve glucose homeostasis, but the mechanism remains unclear.

CONCLUSION

CFRD management is an ongoing concern. Optimal care has reduced the negative impact of CFRD on lung function, nutrition, and survival. Increasing prevalence of CFRD and prolonged lifespan lead to more microvascular complications. New screening tools (Hba1c, CGM, HOMA) show potential for better classification of patients. The effect of CFTR modulators on glucose metabolism warrants further research.

Effect of Hypertonic Saline on Lung Function as Add-on Treatment in People With Cystic Fibrosis Receiving Dornase Alfa: A Cystic Fibrosis Foundation Patient Registry Analysis

BACKGROUND

Introduction of novel therapies for cystic fibrosis (CF) raises the question of whether traditional treatments can be withdrawn. Nebulized hypertonic saline (HS) potentially could be discontinued in patients receiving dornase alfa (DA).

RESEARCH QUESTION

In the era before modulators, did people with CF who are F508del homozygous (CFF508del) and who received DA and HS have better preserved lung function than those treated with DA only?

STUDY DESIGN AND METHODS

Retrospective analysis of the Cystic Fibrosis Foundation Patient Registry data (2006-2014). Among 13,406 CFF508del with data for at least 2 consecutive years, 1,241 CFF508del had spirometry results and were treated with DA for 1 to 5 years without DA or HS during the preceding (baseline) year. Absolute FEV1 % predicted change while receiving DA and HS, relative to treatment with DA only, was the main outcome. A marginal structural model was applied to assess the effect of 1 to 5 years of HS treatment while controlling for time-dependent confounding.

RESULTS

Of 1,241 CFF508del, 619 patients (median baseline age, 14.6 years; interquartile range, 6-53 years) received DA only and 622 patients (median baseline age, 14.55 years; interquartile range, 6-48.1 years) were treated with DA and HS for 1 to 5 years. After 1 year, patients receiving DA and HS showed FEV1 % predicted that averaged 6.60% lower than that in patients treated with DA only (95% CI, -8.54% to -4.66%; P < .001). Lower lung function in the former relative to the latter persisted throughout follow-up, highlighting confounding by indication. After accounting for baseline age, sex, race, DA use duration, baseline and previous year's FEV1 % predicted, and time-varying clinical characteristics, patients treated with DA and HS for 1 to 5 years were similar to those treated with DA only regarding FEV1 % predicted (year 1: mean FEV1 % predicted change, +0.53% [95% CI, -0.66% to +1.71%; P = .38]; year 5: mean FEV1 % predicted change, -1.82% [95% CI, -4.01% to +0.36%; P = .10]).

INTERPRETATION

In the era before modulators, CFF508del showed no significant difference in lung function when nebulized HS was added to DA for 1 to 5 years.

Real world outcomes of CFTR modulator therapy in Australian adults and children

BACKGROUND

Recent advances in CFTR modulator therapy have the potential to change the face of cystic fibrosis (CF). This retrospective observational study describes real world experience of the four available CFTR modulators in adults and children with CF in a single centre in Melbourne, Australia.

METHOD

Data were collected for all patients treated with CFTR modulators at MonashCF between May 2012 and September 2020. Primary outcomes included lung function, admission days and BMI/BMI centile over time. Adverse events and reasons for changing or ceasing medications were also analysed.

RESULTS

55% (74/133) adult and 46% (55/119) paediatric patients were treated with CFTR modulators. FEV1 increased in adults treated with ivacaftor (IVA) and elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) by 4.73% and 10.07% respectively, and BMI also improved in these groups. Nutrition improved in adults and children treated with lumacaftor/ivacaftor (LUM/IVA). There was no significant improvement in FEV1 or admission days with LUM/IVA or tezacaftor/ivacaftor (TEZ/IVA). 36% (31/85) ceased LUM/IVA, due to adverse effects in 81% (25/31). Of these, 92% (23/25) changed to TEZ/IVA, 78% (18/23) without significant adverse effects.

CONCLUSIONS

Our findings for LUM/IVA and TEZ/IVA are less encouraging than those seen in clinical trials, with no significant improvement in lung function or admission days and a higher rate of adverse effects with LUM/IVA compared with phase 3 clinical trials. TEZ/IVA was generally well tolerated by those who experienced side effects with LUM/IVA. The small number of patients treated with ELX/TEZ/IVA had improvements in all parameters. These findings support ongoing use of IVA for individuals with gating mutations, and transition to ELX/TEZ/IVA once available for patients with at least one Phe508del mutation.

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

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

Oxidative Stress Biomarkers in Cystic Fibrosis and Cystic Fibrosis-Related Diabetes in Children: A Literature Review

The most common inherited condition that results in death, particularly in those of Caucasian heritage, is cystic fibrosis (CF). Of all the young adults diagnosed with cystic fibrosis, 20% will develop hyperglycemia as a complication, later classified as a disease associated with cystic fibrosis. Impaired insulin secretion and glucose intolerance represent the primary mechanisms associated with diabetes (type 1 or type 2) and cystic fibrosis. Oxidative stress represents the imbalance between oxygen-reactive species and antioxidant defense mechanisms. This pathogenic mechanism is vital in triggering other chronic diseases, including cystic fibrosis-related diabetes. It is essential to understand oxidative stress and the significant impact it has on CFRD. This way, therapies can be individually adjusted and tailored to each patient's needs. This review aims to understand the connection between CFRD and oxidative stress. As a subsidiary element, we analyzed the effects of glycemic balance on complications and their evolution over time, providing insights into their potential benefits in mitigating oxidative stress-associated complications.

Combined CFTR modulator therapies are linked with anabolic benefits and insulin-sparing in cystic fibrosis-related diabetes

Aims

Combined CFTR modulator therapies have dramatically altered pulmonary outcomes in patients with cystic fibrosis (CF). Their impact on glucose metabolism requires further investigations. This study aims to evaluate insulin requirements after initiation of combined CFTR modulator therapy in patients with CF-related diabetes (CFRD) and HOMA indices changes in CF patients without diabetes.

Methods

We retrospectively analyzed: 1) the effects of tezacaftor + ivacaftor and elexacaftor + tezacaftor + ivacaftor on FEV₁, weight, BMI, HbA1c, and daily insulin dose, in 17 CFRD patients and 2) the impact of tezacaftor + ivacaftor on HOMA indices in 15 CF patients without diabetes.

Results

Age was 37±12y in the CFRD group (70% men), 88% of whom were homozygous for F508del mutation. Diabetes duration was 15±10y. Median duration of combined CFTR modulator therapy was 16 months (IQR: 4) Thirteen patients received tezacaftor + ivacaftor, of whom 9 were switched to elexacaftor + tezacaftor + ivacaftor. Four patients received elexacaftor + tezacaftor + ivacaftor up front. A decrease in insulin needs was noticed in 88% of patients (0.85±0.3 vs 0.71±0.3U/kg/day; p = 0001). Total daily insulin dose decreased from 50±16 to 44±20U/day (p = 0.017). BMI improved (20.9 (IQR: 1.90) vs 22.1 kg/m² (IQR: 3.70); p = 0.014). HbA1c went from 7.3±1.1 to 7.7±1.6% (p = 0.072). Median age was 22y (IQR: 11) in the CF group without diabetes (67% men), 93% of whom were homozygous for F508del mutation. Duration of combined CFTR modulator therapy was 10±5 months. HOMA-B changes were not significant (129.2 (IQR: 84.8) vs 103.5% (IQR: 66.3) nor were HOMA-S changes (from 94±64 to 95±49%). HOMA-BxS decreased from 112±45 to 104±29% (NS). BMI rose from 21.9±3 to 23.1±3.5 kg/m² (p = 0.047). HbA1c was unchanged (5.0±0.5%). FEV₁ improved in both groups (+11% and + 7% of predicted value; p < 0.001; p = 0.013).

Conclusion

Combined CFTR modulator therapies are correlated with a decrease in insulin doses and positive effects on BMI and FEV₁. HOMA indices did not change on tezacaftor + ivacaftor among CF patients without diabetes.

Effects of elexacaftor / tezacaftor / ivacaftor triple combination therapy on glycaemic control and body composition in patients with cystic fibrosis-related diabetes

Cystic fibrosis transmembrane conductance regulator (CFTR) modulators are a group of new drugs for the treatment of cystic fibrosis (CF) and elexacaftor + tezacaftor + ivacaftor (ETI) triple combination therapy has been approved as first choice therapy in the treatment of patients with at least 1 copy of F508del variation. Data on the effects of CFTR modulators on glucose metabolism are limited to small studies with conflicting results. We conducted a prospective observational study on 24 CF patients with CF-related diabetes requiring insulin therapy, with the aim to evaluate the effectiveness of ETI on glucose metabolism, glucose variability and body composition. After six months of treatment, HbA1c and coefficient of variation, measured through flash or continuous glucose monitoring, significantly decreased (median changes: -0.5, P = 0.029 and -6.3, P = 0.008, respectively), despite unchanged insulin requirements. Over the treatment period, percent of fat mass increased by a median value of 3% (p = 0.029).

Patients with cystic fibrosis who could not receive the CFTR modulator treatment: What did they lose in 1 year?

BACKGROUND

Cystic fibrosis (CF) is an autosomal recessive disorder caused by CF transmembrane conductance regulator (CFTR) genetic variants. CFTR modulators improve pulmonary function and reduce respiratory infections in CF. This study investigated the clinical and laboratory follow-up parameters over 1 year in patients with CF who could not receive this treatment.

METHODS

This retrospective cohort study included 2018 and 2019 CF patient data from the CF registry of Turkey. Demographic and clinical characteristics of 294 patients were assessed, who had modulator treatment indications in 2018 but could not reach the treatment.

RESULTS

In 2019, patients younger than 18 years had significantly lower BMI z-scores than in 2018. During the 1-year follow-up, forced expiratory volumes (FEV1) and FEV1 z-scores a trend toward a decrease. In 2019, chronic Staphylococcus aureus colonization, inhaled antipseudomonal antibiotic use for more than 3 months, oral nutritional supplement requirements, and oxygen support need increased.

CONCLUSIONS

Patients who had indications for modulator treatments but were unable to obtain them worsened even after a year of follow-up. This study emphasized the importance of using modulator treatments for patients with CF in our country, as well as in many countries worldwide.

Cystic fibrosis

Cystic fibrosis (CF) is an autosomal recessive genetic disease caused by variants in the gene encoding for the cystic fibrosis transmembrane conductance regulator (CFTR) protein. CFTR dysfunction results in abnormal chloride and bicarbonate transport in epithelial cells, leading to a multiorgan disease dominated by respiratory and digestive manifestations. The respiratory disease, which is characterized by airway mucus plugging, chronic bacterial infection and progressive development of bronchiectasis, may lead to chronic respiratory failure, which is the main cause of premature death in people with CF. Over the past 50 years, major progress has been obtained by implementing multidisciplinary care, including nutritional support, airway clearance techniques and antibiotics in specialized CF centers. The past 10 years have further seen the progressive development of oral medications, called CFTR modulators, that partially restore ion transport and lead to a major improvement in clinical manifestations and lung function, presumably resulting in longer survival. Although an increasing proportion of people with CF are being treated with CFTR modulators, challenges remain regarding access to CFTR modulators due to their high cost, and their lack of marketing approval and/or effectiveness in people with rare CFTR variants. The anticipated increase in the number of adults with CF and their aging also challenge the current organization of CF care. The purpose of this review article is to describe current status and future perspective of CF disease and care.

Experience With Elexacaftor/Tezacaftor/Ivacaftor in Patients With Cystic Fibrosis and Advanced Disease

INTRODUCTION

Elexacaftor/tezacaftor/ivacaftor (ETI) was used through the early access programme in Spain from December 2019 in cystic fibrosis (CF) patients with homozygous or heterozygous F508del mutation with advanced lung disease.

METHODOLOGY

Multicentre, ambispective, observational, study in which 114 patients in follow-up in 16 national CF units were recruited. Clinical data, functional tests, nutritional parameters, quality of life questionnaires, microbiological isolates, number of exacerbations, antibiotic treatments and side effects were collected. The study also compared patients with homozygous and heterozygous F508del mutations.

RESULTS

Of the 114 patients, 85 (74.6%) were heterozygous for F508del mutation, and the mean age was 32.2±9.96 years. After 30 months of treatment, lung function measured by FEV1% showed improvement from 37.5 to 48.6 (p<0.001), BMI increased from 20.5 to 22.3 (p<0.001), and all isolated microorganisms decreased significantly. The total number of exacerbations was also significantly reduced from 3.9 (±2.9) to 0.9 (±1.1) (p<0.001). All items in the CFQ-R questionnaire showed improvement, except for the digestive domain. Oxygen therapy use decreased by 40%, and only 20% of patients referred for lung transplantation remained on the active transplant list. ETI was well-tolerated, with only 4 patients discontinuing treatment due to hypertransaminemia.

CONCLUSIONS

ETI decreases the number of exacerbations, increases lung function and nutritional parameters, decrease in all isolated microorganisms, for 30 months of treatment. There is an improvement in the CFQ-R questionnaire score except for the digestive item. It is a safe and well-tolerated drug.

The revolution of personalized pharmacotherapies for cystic fibrosis: what does the future hold?

INTRODUCTION

Cystic fibrosis (CF), a potentially fatal genetic disease, is caused by loss-of-function mutations in the gene encoding for the CFTR chloride/bicarbonate channel. Modulator drugs rescuing mutant CFTR traffic and function are now in the clinic, providing unprecedented breakthrough therapies for people with CF (PwCF) carrying specific genotypes. However, several CFTR variants are unresponsive to these therapies.

AREA COVERED

We discussed several therapeutic approaches that are under development to tackle the fundamental cause of CF, including strategies targeting defective CFTR mRNA and/or protein expression and function. Alternatively, defective chloride secretion and dehydration in CF epithelia could be restored by exploiting pharmacological modulation of alternative targets, i.e., ion channels/transporters that concur with CFTR to maintain the airway surface liquid homeostasis (e.g., ENaC, TMEM16A, SLC26A4, SLC26A9, and ATP12A). Finally, we assessed progress and challenges in the development of gene-based therapies to replace or correct the mutant CFTR gene.

EXPERT OPINION

CFTR modulators are benefiting many PwCF responsive to these drugs, yielding substantial improvements in various clinical outcomes. Meanwhile, the CF therapy development pipeline continues to expand with the development of novel CFTR modulators and alternative therapeutic strategies with the ultimate goal of providing effective therapies for all PwCF in the foreseeable future.

Prognostic imagination: Genetic counseling amidst therapeutic innovation and evolving futures

Despite the moniker "precision medicine," genetic diagnoses are often imprecise with respect to prognosis. In a period when prognoses are evolving in lockstep with advances in genetic diagnostics and therapeutics, it is critical that clinicians and researchers consider how prognosis is communicated beyond the moment of diagnosis. Research has shown that genetic diagnoses are described differently in pre- and postnatal contexts, but we know relatively little about how patients and families make sense of prognostic information as affected children grow up. Here, I draw on research and personal narratives to describe how prognostic information impacts individuals' conceptions of the future. A deeper understanding of how patients and families view prognosis is important because parents may need support as prognostic conversations arise and because perceptions of prognosis may influence ideas about the future, psychological health, decisions, and planning. By exploring how specific ideas about an individuals' future take hold, clinicians and researchers may begin to identify the benefits, harms, and accuracy of varied sources of prognostic information, opening new areas of bioethical investigation. In closing, I propose prognostic imagination as a useful concept for considering how patients and families experience prognostic information amidst therapeutic innovations and evolving futures.

Elexacaftor/tezacaftor/ivacaftor projected survival and long-term health outcomes in people with cystic fibrosis homozygous for F508del

BACKGROUND

A series of phase 3 clinical trials have demonstrated that elexacaftor plus tezacaftor plus ivacaftor (ELX/TEZ/IVA) is safe and efficacious in people with cystic fibrosis (pwCF) aged ≥12 years with ≥1 F508del mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The impact of this treatment on lifetime clinical outcomes and survival, however, has yet to be assessed.

METHODS

We used a person-level microsimulation model to estimate the survival and lifetime clinical benefits of ELX/TEZ/IVA treatment versus other CFTR modulator combinations (tezacaftor plus ivacaftor [TEZ/IVA] or lumacaftor plus ivacaftor [LUM/IVA]) or best supportive care (BSC) alone in pwCF aged ≥12 years who are homozygous for F508del-CFTR. Disease progression inputs were derived from published literature; clinical efficacy inputs were derived from an indirect treatment comparison conducted using relevant phase 3 clinical trial data and extrapolations of clinical data.

RESULTS

The median projected survival for pwCF homozygous for F508del-CFTR treated with ELX/TEZ/IVA was 71.6 years. This was an increase of 23.2 years versus TEZ/IVA, 26.2 years versus LUM/IVA, and 33.5 years versus BSC alone. Treatment with ELX/TEZ/IVA also reduced disease severity as well as the number of pulmonary exacerbations and lung transplants. In a scenario analysis, the median projected survival for pwCF initiating ELX/TEZ/IVA between the ages of 12 and 17 years was 82.5 years, an increase of 45.4 years compared with BSC alone.

CONCLUSIONS

The results from our model suggest ELX/TEZ/IVA treatment may substantially increase survival for pwCF, with early initiation potentially allowing pwCF to achieve near-normal life expectancy.

Improved glucose tolerance after initiation of Elexacaftor / Tezacaftor / Ivacaftor in adults with cystic fibrosis

BACKGROUND

The novel triple CFTR modulator therapy Elexacaftor/Tezacaftor/Ivacaftor (ELX/TEZ/IVA) improves lung function, body mass index (BMI), sinus clearance, and quality of life in patients with cystic fibrosis. Whether treatment with ELX/TEZ/IVA is associated with improved glucose tolerance is unknown.

METHODS

This cohort study included adults with CF and at least one copy of F508del.. Study assessments before treatment and at least 3 months after ELX/TEZ/IVA initiation included an oral glucose tolerance test (OGTT) with glucose and insulin measurements, BMI, lung function test, and sweat chloride levels. We used an analysis of response profiles to calculate changes in outcomes.

RESULTS

33 patients (27.8 ± 6.3 years; 73% male; 64% F508del homozygous) were included. After a median of 184 [IQR, 107 - 278] days following treatment initiation 16 (48.5%) patients improved their glucose tolerance category, while 13 (39.4%) remained unchanged and 4 (12.1%) deteriorated. Overall, 60, 90 and 120 min OGTT glycemia decreased significantly from 11.9 ± 2.7 mmol/l to 10.6 ± 2.8 mmol/l (p = 0.012), 10.4 ± 3.0 mmol/l to 8.4 ± 3.6 mmol/l (p = 0.002) and 7.3 ± 3.1 mmol/l to 5.7 ± 3.0 mmol/l (p = 0.012). HbA1c levels also improved significantly, from 5.50±0.24% to 5.39±0.25% (p = 0.039).

CONCLUSION

In adult patients with CF and at least one copy of F508del, treatment with the triple CFTR modulator was associated with possible improvement of glucose tolerance without increases of insulin secretion. Early initiation of treatment as assessed through long-term prospective trials is mandatory to demonstrate if decreased glucose control is preventable or even reversible.

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

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

Cystic Fibrosis: A Review

Importance

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

Observations

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

Conclusion

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

Cystic Fibrosis-Related Diabetes Workshop: Research Priorities Spanning Disease Pathophysiology, Diagnosis, and Outcomes

Cystic fibrosis (CF) is a recessive disorder arising from mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR) protein. CFTR is expressed in numerous tissues, with high expression in the airways, small and large intestine, pancreatic and hepatobiliary ducts, and male reproductive tract. CFTR loss in these tissues disrupts regulation of salt, bicarbonate, and water balance across their epithelia, resulting in a systemic disorder with progressive organ dysfunction and damage. Pancreatic exocrine damage ultimately manifests as pancreatic exocrine insufficiency that begins as early as infancy. Pancreatic remodeling accompanies this early damage, during which abnormal glucose tolerance can be observed in toddlers. With increasing age, however, insulin secretion defects progress such that CF-related diabetes (CFRD) occurs in 20% of teens and up to half of adults with CF. The relevance of CFRD is highlighted by its association with increased morbidity, mortality, and patient burden. While clinical research on CFRD has greatly assisted in the care of individuals with CFRD, key knowledge gaps on CFRD pathogenesis remain. Furthermore, the wide use of CFTR modulators to restore CFTR activity is changing the CFRD clinical landscape and the field's understanding of CFRD pathogenesis. For these reasons, the National Institute of Diabetes and Digestive and Kidney Diseases and the Cystic Fibrosis Foundation sponsored a CFRD Scientific Workshop, 23-25 June 2021, to define knowledge gaps and needed research areas. This article describes the findings from this workshop and plots a path for CFRD research that is needed over the next decade.

Cystic Fibrosis-Related Diabetes Workshop: Research Priorities Spanning Disease Pathophysiology, Diagnosis, and Outcomes

Cystic fibrosis (CF) is a recessive disorder arising from mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR) protein. CFTR is expressed in numerous tissues, with high expression in the airways, small and large intestine, pancreatic and hepatobiliary ducts, and male reproductive tract. CFTR loss in these tissues disrupts regulation of salt, bicarbonate, and water balance across their epithelia, resulting in a systemic disorder with progressive organ dysfunction and damage. Pancreatic exocrine damage ultimately manifests as pancreatic exocrine insufficiency that begins as early as infancy. Pancreatic remodeling accompanies this early damage, during which abnormal glucose tolerance can be observed in toddlers. With increasing age, however, insulin secretion defects progress such that CF-related diabetes (CFRD) occurs in 20% of teens and up to half of adults with CF. The relevance of CFRD is highlighted by its association with increased morbidity, mortality, and patient burden. While clinical research on CFRD has greatly assisted in the care of individuals with CFRD, key knowledge gaps on CFRD pathogenesis remain. Furthermore, the wide use of CFTR modulators to restore CFTR activity is changing the CFRD clinical landscape and the field's understanding of CFRD pathogenesis. For these reasons, the National Institute of Diabetes and Digestive and Kidney Diseases and the Cystic Fibrosis Foundation sponsored a CFRD Scientific Workshop, 23-25 June 2021, to define knowledge gaps and needed research areas. This article describes the findings from this workshop and plots a path for CFRD research that is needed over the next decade.

Factors associated with frequent high-cost individuals with cystic fibrosis and their healthcare utilization and cost patterns

Cystic fibrosis (CF) is a progressive multi-organ disease with significant morbidity placing extensive demands on the healthcare system. Little is known about those individuals with CF who continually incur high costs over multiple years. Understanding their characteristics may help inform opportunities to improve management and care, and potentially reduce costs. The purpose of this study was to identify and understand the clinical and demographic attributes of frequent high-costing CF individuals and characterize their healthcare utilization and costs over time. A longitudinal study of retrospective data was completed in British Columbia, Canada by linking the Canadian CF Registry with provincial healthcare administrative databases for the period between 2009 and 2017. Multivariable Cox regression models were employed to identify baseline factors associated with becoming a frequent high-cost CF user (vs. not a frequent high-cost CF user) in the follow-up period. We found that severe lung impairment (Hazard Ratio [HR]: 3.71, 95% confidence interval [CI], 1.49-9.21), lung transplantation (HR: 4.23, 95% CI, 1.68-10.69), liver cirrhosis with portal hypertension (HR: 10.96, 95% CI: 3.85-31.20) and female sex (HR: 1.97, 95% CI: 1.13-3.44) were associated with becoming a frequent high-cost CF user. Fifty-nine (17% of cohort) frequent high-cost CF users accounted for more than one-third of the overall total healthcare costs, largely due to inpatient hospitalization and outpatient medication costs.

Registry-based study in people with cystic fibrosis and an R117H variant treated with ivacaftor

BACKGROUND

Ivacaftor approval was extended to people with cystic fibrosis (CF) and an R117H variant in 2014 in the USA. This observational, real-world, postapproval study evaluated long-term outcomes among people with CF and an R117H variant on ivacaftor using data from the US Cystic Fibrosis Foundation Patient Registry.

METHODS

Key outcomes were evaluated in ivacaftor-treated people with CF and an R117H variant for up to 36 months before and after treatment initiation using within-group comparisons. Analyses were descriptive in nature, focused on evaluation of observed outcome patterns over time and were performed both overall and for age groups ≥2 to <6 years, ≥6 to <18 years and ≥18 years. Key outcomes included lung function, body mass index (BMI), pulmonary exacerbations (PEx) and hospitalisations.

RESULTS

The ivacaftor cohort included 369 people with CF and an R117H variant who initiated therapy between 1 January 2015 and 31 December 2016. During each of the 12-month intervals following treatment initiation, the mean observed percent predicted forced expiratory volume in 1 s (ppFEV₁) and BMI values were higher and the mean annualised number of PEx and hospitalisation events were lower than pretreatment values. Mean change in ppFEV₁ from pretreatment baseline was an increase of 1.5 (95% CI 0.8 to 2.3), 1.7 (95% CI 0.7 to 2.7) and 1.8 (95% CI 0.6 to 3.0) percentage points in the first, second and third years of treatment, respectively. Similar trends were observed in adult and paediatric subgroups.

CONCLUSIONS

The results support the clinical effectiveness of ivacaftor in people with CF and an R117H variant, including adult and paediatric subgroups.

Survey of exercise testing and training in cystic fibrosis clinics in the UK: a decade of progress

OBJECTIVES

Regular exercise testing is recommended for people with cystic fibrosis (pwCF), as is the provision and regular review of exercise training programmes. A previous survey on exercise testing and training for pwCF in the UK was conducted over a decade ago. With the landscape of CF changing considerably during this time, this survey aimed to evaluate UK-based exercise testing and training practices for pwCF a decade on.

DESIGN

Cross-sectional, online survey.

PARTICIPANTS

A survey was distributed electronically to UK CF clinics and completed by the individual primarily responsible for exercise services. Descriptive statistics and qualitative analyses were undertaken.

RESULTS

In total, 31 CF centres participated, representing ~50% of UK specialist clinics. Of these, 94% reported using exercise testing, 48% of which primarily use cardiopulmonary exercise testing. Exercise testing mostly occurs at annual review (93%) and is most often conducted by physiotherapists (62%). A wide variation in protocols, exercise modalities, normative reference values and cut-offs for exercise-induced desaturation are currently used. All centres reportedly discuss exercise training with pwCF; 94% at every clinic appointment. However, only 52% of centres reportedly use exercise testing to inform individualised exercise training. Physiotherapists typically lead discussions around exercise training (74%).

CONCLUSIONS

These data demonstrate that the majority of respondent centres in the UK now offer some exercise testing and training advice for pwCF, representing a marked improvement over the past decade. However, continued efforts are now needed to standardise exercise practices, particularly regarding field testing practices and the translation of test results into personalised training programmes for pwCF.

Calibration and validation of modeled 5-year survival predictions among people with cystic fibrosis treated with the cystic fibrosis transmembrane conductance regulator modulator ivacaftor using United States registry data

OBJECTIVES

Cystic fibrosis (CF) is a rare genetic disease characterized by life-shortening lung function decline. Ivacaftor, a CF transmembrane conductance regulator modulator (CFTRm), was approved in 2012 for people with CF with specific gene mutations. We used real-world evidence of 5-year mortality impacts of ivacaftor in a US registry population to validate a CF disease-progression model that estimates the impact of ivacaftor on survival.

METHODS

The model projects the impact of ivacaftor vs. standard care in people with CF aged ≥6 years with CFTR gating mutations by combining parametric equations fitted to historical registry survival data, with mortality hazards adjusted for fixed and time-varying person-level characteristics. Disease progression with standard care was derived from published registry studies and the expected impact of ivacaftor on clinical characteristics was derived from clinical trials. Individual-level baseline characteristics of the registry ivacaftor-treated population were entered into the model; 5-year model-projected mortality with credible intervals (CrIs) was compared with registry mortality to evaluate the model's validity.

RESULTS

Post-calibration 5-year mortality projections closely approximated registry mortality in populations treated with standard care (6.4% modeled [95% CrI: 5.3% to 7.6%] vs. 6.0% observed) and ivacaftor (3.4% modeled [95% CrI: 2.7% to 4.4%] vs. 3.1% observed). The model accurately predicted 5-year relative risk of mortality (0.53 modeled [0.47 to 0.60] vs. 0.51 observed) in people treated with ivacaftor vs. standard care.

CONCLUSIONS

Modeled 5-year survival projections for people with CF initiating ivacaftor vs. standard care align closely with real-world registry data. Findings support the validity of modeling CF to predict long-term survival and estimate clinical and economic outcomes of CFTRm.

Improvements in Glucose Regulation in Children and Young People with Cystic Fibrosis-Related Diabetes following Initiation of Elexacaftor/Tezacaftor/Ivacaftor

INTRODUCTION

Cystic fibrosis transmembrane conductance regulator (CFTR) modulators are increasingly used in children and young people with cystic fibrosis (CF). Data in adults show there may be an impact on glycaemic control in those with CF-related diabetes (CFRD). Paediatric data are rare. Case Series/Presentation: Children aged >12 years with CFRD, who were eligible for elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) were commenced on treatment. Glucose monitoring via the FreeStyle Libre system was commenced prior to, immediately after, and several months after commencing ELX/TEZ/IVA. Glycaemic control, shown by time in range (3-10 mmol/L), percentage of time spent hypoglycaemic (<3 mmol/L), and percentage of time spent hyperglycaemic (>10 mmol/L) on Insulin doses were recorded. Following ELX/TEZ/IVA, four of seven children stopped insulin, two required substantially reduced doses of insulin, one showed no response. Glycaemic control remained similar on lower doses or no insulin. Hypoglycaemia was detected in those not requiring insulin.

CONCLUSION

ELX/TEZ/IVA has a positive impact on glycaemic control and insulin requirements in children with CFRD. Close monitoring is required when commencing treatment. Children with CFRD need counselling regarding possible reductions in insulin requirement and re-education regarding symptoms, signs, and management of hypoglycaemia.

Inflammation as a Regulator of the Airway Surface Liquid pH in Cystic Fibrosis

The airway surface liquid (ASL) is a thin sheet of fluid that covers the luminal aspect of the airway epithelium. The ASL is a site of several first-line host defenses, and its composition is a key factor that determines respiratory fitness. Specifically, the acid-base balance of ASL has a major influence on the vital respiratory defense processes of mucociliary clearance and antimicrobial peptide activity against inhaled pathogens. In the inherited disorder cystic fibrosis (CF), loss of cystic fibrosis transmembrane conductance regulator (CFTR) anion channel function reduces HCO3- secretion, lowers the pH of ASL (pHASL), and impairs host defenses. These abnormalities initiate a pathologic process whose hallmarks are chronic infection, inflammation, mucus obstruction, and bronchiectasis. Inflammation is particularly relevant as it develops early in CF and persists despite highly effective CFTR modulator therapy. Recent studies show that inflammation may alter HCO3- and H+ secretion across the airway epithelia and thus regulate pHASL. Moreover, inflammation may enhance the restoration of CFTR channel function in CF epithelia exposed to clinically approved modulators. This review focuses on the complex relationships between acid-base secretion, airway inflammation, pHASL regulation, and therapeutic responses to CFTR modulators. These factors have important implications for defining optimal ways of tackling CF airway inflammation in the post-modulator era.

Advanced Cystic Fibrosis Lung Disease and Lung Transplantation in the Era of Cystic Fibrosis Transmembrane Conductance Regulator Modulators

Cystic fibrosis transmembrane conductance regulator (CFTR) modulators have changed the clinical landscape of cystic fibrosis (CF) by improving clinically significant outcome measures and quality of life of people with CF (pwCF). There are now long-term data showing improved 5-year survival with the use of ivacaftor, and the field continues to evolve at a rapid pace with the continued development of highly effective CFTR modulators. While the randomized controlled trials of CFTR modulators excluded patients with severe lung disease (forced expiratory volume in 1 second <40% predicted), observational data based on case reports and registry data show similar benefits in those with advanced lung disease. This has altered clinical practice particularly as it pertains to the role of lung transplantation in CF. This article describes the impact of highly effective modulator therapy (HEMT) on the natural history of CF and the influence on the timing of referral and consideration of listing for lung transplantation. CF clinicians play a pivotal role to ensure that the impetus of the CF foundation consensus guidelines to facilitate timely referral for lung transplantation is not lost among the excitement of anticipated sustained benefit from HEMT. While the widespread availability of elexacaftor/tezacaftor/ivacaftor over the past 2 years has been associated with a sharp drop in the number of people referred for consideration for lung transplantation and the number of people wait-listed for lung transplantation, it is difficult to accurately determine the true impact due to the confounding effect of the coronavirus disease 2019 pandemic. It is expected that lung transplantation will remain an important treatment for a smaller number of pwCF. Lung transplantation offers survival benefits in CF, and there remains an imperative to ensure timely consideration of lung transplantation in patients with advanced disease to further reduce the number of pwCF dying without consideration of lung transplant.

Development of the Cystic Fibrosis Questionnaire-Revised-8 Dimensions: Estimating Utilities From the Cystic Fibrosis Questionnaire-Revised

OBJECTIVES

Cystic fibrosis (CF) limits survival and negatively affects health-related quality of life (HRQOL). Cost-effectiveness analysis (CEA) may be used to make reimbursement decisions for new CF treatments; nevertheless, generic utility measures used in CEA, such as EQ-5D, are insensitive to meaningful changes in lung function and HRQOL in CF. Here we develop a new, CF disease-specific, preference-based utility measure based on the adolescent/adult version of the Cystic Fibrosis Questionnaire-Revised (CFQ-R), a widely used, CF-specific, patient-reported measure of HRQOL.

METHODS

Blinded CFQ-R data from 4 clinical trials (NCT02347657, NCT02392234, NCT01807923, and NCT01807949) were used to identify discriminating items for a classification system using psychometric (eg, factor and Rasch) analyses. Thirty-two health states were selected for a time trade-off (TTO) exercise with a representative sample of the UK general population. TTO utilities were used to estimate a preference-based scoring algorithm by regression analysis (tobit models with robust standard errors clustered on participants with censoring at -1).

RESULTS

A classification system with 8 dimensions (CFQ-R-8 dimensions; physical functioning, vitality, emotion, role functioning, breathing difficulty, cough, abdominal pain, and body image) was generated. TTO was completed by 400 participants (mean age, 47.3 years; 49.8% female). Among the regression models evaluated, the tobit heteroscedastic-ordered model was preferred, with a predicted utility range from 0.236 to 1, no logical inconsistencies, and a mean absolute error of 0.032.

CONCLUSION

The CFQ-R-8 dimensions is the first disease-specific, preference-based scoring algorithm for CF, enabling estimation of disease-specific utilities for CEA based on the well-validated and widely used CFQ-R.

Clinical change 2 years from start of elexacaftor-tezacaftor-ivacaftor in severe cystic fibrosis

RATIONALE

Limited published research is available on the impact of elexacaftor/tezacaftor/ivacaftor (ETI) beyond the initial few months postdrug initiation, especially for those who initiated therapy via individual investigational new drug application. The experiences of patients with cystic fibrosis (CF) experiencing severe lung disease were reviewed for significant improvements in clinical symptoms and quality of life.

OBJECTIVES

To examine clinical outcomes 2 years post-ETI in patients with CF and advanced lung disease.

METHODS

This single center institutional review board-approved, retrospective chart review assessed clinical markers (percent predicted forced expiratory volume in 1 s, weight, sweat chloride), quality of life and computed tomography scans in patients with advanced lung disease who met criteria for compassionate use/expanded access program due to high risk of death or transplant need within 2 years.

RESULTS

Eighteen identified patients (ages 15-49 years) initiated drug between July and September 2019. Clinical markers indicated that therapy was well tolerated, not discontinued by any participant, and lab values did not indicate medical concern or discontinuation. Monitoring results indicated the safety of modulator therapy as there were no adverse clinical occurrences and all patients presented universal stabilization. There were no deaths and no transplants by the end of the study.

CONCLUSIONS

This study focused on patients with CF eligible for modulator therapy and were initiated due to advanced lung disease. Initiation of modulator therapy was deemed safe and resulted in objective positive changes in nutrition, cough, FEV₁ , subjective reports of clinical status, level of activity, and a reduction in burden of treatment.

Screening strategies for glucose tolerance abnormalities and diabetes in people with cystic fibrosis

The increase in life expectancy of patients with cystic fibrosis has come with new comorbidities, particularly diabetes. The gradual development of glucose tolerance abnormalities means that 30 to 40% of adults will be diabetic. Cystic fibrosis-related diabetes is a major challenge in the care of these patients because it is a morbidity and mortality factor at all stages of the disease. Early glucose tolerance abnormalities observed from childhood, before the stage of diabetes, are also associated with a poor pulmonary and nutritional outcome. The long asymptomatic period justifies systematic screening with an annual oral glucose tolerance test from the age of 10 years. However, this strategy does not take into account the new clinical profiles of patients with cystic fibrosis, recent pathophysiological knowledge of glucose tolerance abnormalities, and the emergence of new diagnostic tools in diabetology. In this paper, we summarise the challenges of screening in the current context of new patient profiles - patients who are pregnant, have transplants, or are being treated with fibrosis conductance transmembrane regulator modulators - and put forward an inventory of the various screening methods for cystic fibrosis-related diabetes, including their applications, limitations and practical implications.

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.

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

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

Ivacaftor: Five-year outcomes in the West of Scotland cystic fibrosis population

INTRODUCTION

Ivacaftor has shown to be effective in patients with cystic fibrosis (CF) with a G551D mutation.

OBJECTIVES

This work aims to evaluate ivacaftor's effectiveness and safety in the real world, over 5 years, in the West of Scotland CF population.

METHODS

We evaluated ivacaftor's effect on pulmonary function, body mass index (BMI), hospital bed occupancy, and adverse effects in patients ≥6 years with at least one G551D mutation.

RESULTS

Statistically significant increases from baseline were observed in mean per cent predicted forced expiratory volume in 1 s (FEV₁ ) at year 1 (which was maintained at years 2 and 5) and BMI over 5 years in our adolescent/adult cohort. Improvements were observed in per cent predicted FEV₁ within the paediatric cohort with a suggestion of a plateau effect. The increase in paediatric BMI z-score was nonstatistically significant. There was a reduction in the number of pulmonary exacerbations requiring intravenous antibiotics and hospital bed occupancy. Ivacaftor was well tolerated.

CONCLUSION

Ivacaftor was effective in our population.

Distribution of OGTT-Related Variables in Patients with Cystic Fibrosis from Puberty to Adulthood: An Italian Multicenter Study

Background: Insulin secretion and glucose tolerance is annually assessed in patients with cystic fibrosis (PwCF) through oral glucose tolerance tests (OGTTs) as a screening measure for cystic fibrosis-related diabetes. We aimed to describe the distribution and provide reference quartiles of OGTT-related variables in the Italian cystic fibrosis population. Methods: Cross-sectional study of PwCF receiving care in three Italian cystic fibrosis centers of excellence, from 2016 to 2020. We performed a modified 2-h OGTT protocol (1.75 g/kg, maximum 75 g), sampling at baseline and at 30-min intervals, analyzing plasma glucose, serum insulin, and C-peptide. The modified OGTT allowed for the modeling of β cell function. For all variables, multivariable quantile regression was performed to estimate the median, the 25th, and 75th percentiles, with age, sex, and pancreatic insufficiency as predictors. Results: We have quantified the deterioration of glucose tolerance and insulin secretion with age according to sex and pancreatic insufficiency, highlighting a deviation from linearity both for patients <10 years and >35 years of age. Conclusions: References of OGTT variables for PwCF provide a necessary tool to not only identify patients at risk for CFRD or other cystic fibrosis-related complications, but also to evaluate the effects of promising pharmacological therapies.

The Impact of Highly Effective Cystic Fibrosis Transmembrane Conductance Regulator Modulators on the Health of Female Subjects With CF

Cystic fibrosis (CF) is a genetic disorder that occurs in people of all genetic ancestries. CF is caused by variants in the CF transmembrane conductance regulator (CFTR) gene that result in decreased, absent, or nonfunctional CFTR protein at the cell surface of the mucous membranes. Clinical manifestations include chronic respiratory disease, malabsorption, and decreased fertility. Historically, therapies for CF were focused on the signs and symptoms of the disease. However, more recently, CFTR modulators, therapies directed at the basic defect, are improving the quality and duration of the lives of people with CF. The predicted survival of people with CF in the United States is now 53 years of age. With the hope of longer, healthier lives, female individuals with CF (fwCF) are expressing the desire to discuss fertility, pregnancy, and parenthood. Furthermore, pregnancy rates are increasing substantially. Understanding the impact of use or discontinuation of highly effective modulator therapy on the reproductive health of fwCF is critical. Finally, fwCF and their providers must consider preventative cancer screening. (Clin Ther. 2023;45:XXX-XXX) © 2023 Elsevier HS Journals, Inc.

Lessons from other fields of medicine, Part 2: Cystic fibrosis

Cystic fibrosis (CF), first described in 1938, is a common, life-limiting monogenetic disease. The discovery of the cystic fibrosis transmembrane conductance regulator (CFTR) gene in 1989 was crucial in advancing our understanding of disease pathogenesis and paving the road for treatment aimed at the fundamental molecular defect. With the delineation of over 2000 variations in the CFTR gene, a sound understanding of the individual variations in cell biology, and electrophysiological abnormalities conferred by the most common defects propelled the advent of targeted disease-modifying therapeutics beginning in 2012. Since then, CF care has transformed beyond just symptomatic treatment to include a variety of small-molecule therapies that address the basic electrophysiologic defect and cause profound improvements in physiology, clinical manifestations, and long-term outcomes, designed to differentially address six genetic/molecular subtypes. This chapter illustrates the progress made toward how fundamental science and translational initiatives enabled personalized, mutation specific treatment. We highlight the importance of preclinical assays and mechanistically-driven development strategies that were coupled with sensitive biomarkers and a clinical trial cooperative to provide a platform for successful drug development. This convergence of academic and private partnerships, and formation of multidisciplinary care teams directed by evidence-based initiatives provide a seminal example of addressing the needs of individuals with a rare, but fatal genetic disease.