Efficacy and safety of lumacaftor and ivacaftor in patients aged 6–11 years with cystic fibrosis homozygous for F508del-CFTR : a randomised, placebo-controlled phase 3 trial

New Therapies in Outpatient Pulmonary Medicine

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

Advances in Pediatric Lung Function Testing Techniques

For decades spirometry has been the benchmark test for capturing lung function in children but its recognized limitations required the development of other techniques. This article introduces novel techniques in lung function assessment for pediatric patients, including multiple breath washout, impulse oscillometry, structured light plethysmography, and electrical impedance tomography, and common themes in interpreting the results. Challenges include standardization, reference data, and clinical integration of these innovative tools. Further research is ongoing to optimize these tests for clinical use, especially in diverse populations and pediatric settings.

Advances in Care and Outcomes for Children with Cystic Fibrosis

The landscape of care for children with cystic fibrosis (CF), a genetic disorder of chloride transport with multisystem manifestations including inspissated mucus, recurrent sinopulmonary infections, obstructive lung disease, and exocrine pancreatic insufficiency, is rapidly changing. Early diagnosis via newborn screening enabling timely nutritional support, chronic therapies to improve mucociliary clearance, and prompt treatment of pulmonary infections have improved overall outcomes in children with CF. More widespread availability of novel cystic fibrosis transmembrane conductance regulator modulator therapies for children continues to revolutionize pediatric CF care.However, significant challenges exist to optimize care and outcomes for all children with CF.

Cystic fibrosis screening, evaluation, and management of hepatobiliary disease consensus recommendations

Cystic fibrosis (CF) may cause a spectrum of hepatobiliary complications, including portal hypertension, multilobular cirrhosis, and liver failure. Current guidelines on the detection and monitoring of hepatobiliary complications in CF were published in 1999. The CF Foundation assembled a committee to evaluate research advances and formulate revised guidelines for CF-associated liver disease. A committee of hepatologists, gastroenterologists, pulmonologists, pharmacists, nurses, dietitians, individuals with CF, and the parents of a child with CF devised "population, intervention, comparison, and outcome" questions regarding hepatobiliary disease in CF. PubMed literature searches were performed for each population, intervention, comparison, and outcome question. Recommendations were voted on with 80% agreement required to approve a recommendation. Public comment on initial recommendations was solicited prior to the formulation of final recommendations. Thirty-one population, intervention, comparison, and outcome questions were assembled, 6401 manuscripts were title screened for relevance, with 1053 manuscripts undergoing detailed full-text review. Seven recommendations were approved for screening, 13 for monitoring of existing disease, and 14 for treatment of CF-associated hepatobiliary involvement or advanced liver disease. One recommendation on liver biopsy did not meet the 80% threshold. One recommendation on screening ultrasound was revised and re-voted on. Through a multidisciplinary committee and public engagement, we have assembled updated recommendations and guidance on screening, monitoring, and treatment of CF-associated hepatobiliary involvement and advanced liver disease. While research gaps remain, we anticipate that these recommendations will lead to improvements in CF outcomes through earlier detection and increased evidence-based approaches to monitoring and treatment.

The effect of respiratory muscle training on children and adolescents with cystic fibrosis: a systematic review and meta-analysis

BACKGROUND

Cystic fibrosis is a chronic genetic disease that can affect the function of the respiratory system. Previous reviews of the effects of respiratory muscle training in people with cystic fibrosis are uncertain and do not consider the effect of age on disease progression. This systematic review aims to determine the effectiveness of respiratory muscle training in the clinical outcomes of children and adolescents with cystic fibrosis.

METHODS

Up to July 2023, electronic databases and clinical trial registries were searched. Controlled clinical trials comparing respiratory muscle training with sham intervention or no intervention in children and adolescents with cystic fibrosis. The primary outcomes were respiratory muscle strength, respiratory muscle endurance, lung function, and cough. Secondary outcomes included exercise capacity, quality of life and adverse events. Two review authors independently extracted data and assessed study quality using the Cochrane Risk of Bias Tool 2. The certainty of the evidence was assessed according to the GRADE approach. Meta-analyses where possible; otherwise, take a qualitative approach.

RESULTS

Six studies with a total of 151 participants met the inclusion criteria for this review. Two of the six included studies were published in abstract form only, limiting the available information. Four studies were parallel studies and two were cross-over designs. There were significant differences in the methods and quality of the methodology included in the studies. The pooled data showed no difference in respiratory muscle strength, lung function, and exercise capacity between the treatment and control groups. However, subgroup analyses suggest that inspiratory muscle training is beneficial in increasing maximal inspiratory pressure, and qualitative analyses suggest that respiratory muscle training may benefit respiratory muscle endurance without any adverse effects.

CONCLUSIONS

This systematic review and meta-analysis indicate that although the level of evidence indicating the benefits of respiratory muscle training is low, its clinical significance suggests that we further study the methodological quality to determine the effectiveness of training.

TRIAL REGISTRATION

The protocol for this review was recorded in the International Prospective Register of Systematic Reviews (PROSPERO) under registration number CRD42023441829.

Case Report: When cystic fibrosis, elexacaftor/tezacaftor/ivacaftor therapy, and alpha1 antitrypsin deficiency get together

In the last 10 years, the care of patients with cystic fibrosis (CF) has been revolutionized with the introduction of cystic fibrosis transmembrane conductance regulator (CFTR) modulator drugs, with a major impact on symptoms and life expectancy, especially considering the newest and highly effective elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) therapy. Conversely, adverse effects are relatively frequent, with some being life-threatening, such as severe hepatitis. Clinical trials on children starting CFTR modulators have reported transaminase elevations >3× upper limit of the norm in 10%-20% of patients, whereas real-life studies have reported discontinuation rates three times higher than those observed in phase 3 trials. We report the case of a 10-year-old boy with CF who developed severe acute hepatitis 2 weeks after starting ELX/TEZ/IVA therapy. An extensive screening for potential causes led to the identification of heterozygous alpha1-antitrypsin (AAT) deficiency with genotype MZ. The Z allele of SERPINA1 gene, encoding AAT, is known as a risk factor for CF liver disease. We hypothesized that it may act as a risk factor for drug-induced liver injury from CFTR modulators, notably ELX/TEZ/IVA. Therefore, checking AAT before starting CFTR modulator therapy can be suggested, in particular for children with previous, even transient, liver disease.

Paediatric Thoracic Imaging in Cystic Fibrosis in the Era of Cystic Fibrosis Transmembrane Conductance Regulator Modulation

Cystic fibrosis (CF) is one of the most common progressive life-shortening genetic conditions worldwide. Ground-breaking translational research has generated therapies that target the primary cystic fibrosis transmembrane conductance regulator (CFTR) defect, known as CFTR modulators. A crucial aspect of paediatric CF disease is the development and progression of irreversible respiratory disease in the absence of clinical symptoms. Accurate thoracic diagnostics have an important role to play in this regard. Chest radiographs are non-specific and insensitive in the context of subtle changes in early CF disease, with computed tomography (CT) providing increased sensitivity. Recent advancements in imaging hardware and software have allowed thoracic CTs to be acquired in paediatric patients at radiation doses approaching that of a chest radiograph. CFTR modulators slow the progression of CF, reduce the frequency of exacerbations and extend life expectancy. In conjunction with advances in CT imaging techniques, low-dose thorax CT will establish a central position in the routine care of children with CF. International guidelines regarding the choice of modality and timing of thoracic imaging in children with CF are lagging behind these rapid technological advances. The continued progress of personalised medicine in the form of CFTR modulators will promote the emergence of personalised radiological diagnostics.

CFTR Modulators: From Mechanism to Targeted Therapeutics

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

Real-life experience with a generic formulation of lumacaftor-ivacaftor in patients with cystic fibrosis homozygous for the Phe508del CFTR mutation

INTRODUCTION

Cystic fibrosis (CF) is the most frequent recessive autosomal disorder in the Caucasian population. It is caused by mutations that result in a deficient or dysfunctional cystic fibrosis transmembrane conductance regulator (CFTR) protein activity. Among CFTR modulators, potentiator compounds increase channel opening, whereas corrector compounds increase CFTR quantity in the cell surface.

OBJECTIVE

To report real-life effects of a generic formulation of lumacaftor-ivacaftor use in patients with CF homozygous for the Phe508del CFTR mutation.

PATIENTS AND METHODS

Clinical variables (body mass index [BMI], pulmonary exacerbations, sweat test, and pulmonary function) were analyzed in 30 CF patients homozygous for the Phe508del CFTR mutation, treated with lumacaftor-ivacaftor for 12 months, at the Respiratory Center of Hospital de Niños Ricardo Gutiérrez. These clinical variables were compared with those before the use of modulators.

RESULTS

A total of 30 patients with CF homozygous for the Phe508del CFTR mutation receiving lumacaftor-ivacaftor therapy were included in this study. The median (interquartile range [IQR]) age at the start of treatment was 10.79 (7.08-14.05) years. Nineteen patients were male. Before treatment, median (IQR) sweat chloride concentration was 80 (72-92) mEq/L, and it had decreased to 74 (68-78) mEq/L (p = .05) 12 months after treatment. Median (IQR) BMI z-score improved from -0.33 (-0.86 to 0.21) to -0.13 (-0.66 to 0.54) (p = .003). A spirometry was performed in 28 of 30 patients. Median (IQR) ppFEV1 was 83.5 (71-91) before treatment and 86.5 (67-103) after treatment (p = .38), 73.3% of patients referred decreased sputum production and 40% reported improvement in their dyspnea at 12 months. Severe pulmonary exacerbations significantly decreased from 60% in the year before treatment, to 30% at 12 months after treatment (p = .037); 13 patients showed an improvement in their exacerbation rates, 2 showed an increased rate, and 15 showed no change.

CONCLUSIONS

The use of a generic formulation of lumacaftor-ivacaftor in patients homozygous for the Phe508del CFTR mutation was associated with improvement in nutritional status and respiratory symptoms, and a significant reduction in severe pulmonary exacerbations.

Trials and tribulations of highly effective modulator therapies in cystic fibrosis

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

Corrector therapies (with or without potentiators) for people with cystic fibrosis with class II CFTR gene variants (most commonly F508del)

BACKGROUND

Cystic fibrosis (CF) is a common life-shortening genetic condition caused by a variant in the cystic fibrosis transmembrane conductance regulator (CFTR) protein. A class II CFTR variant F508del is the commonest CF-causing variant (found in up to 90% of people with CF (pwCF)). The F508del variant lacks meaningful CFTR function - faulty protein is degraded before reaching the cell membrane, where it needs to be to effect transepithelial salt transport. Corrective therapy could benefit many pwCF. This review evaluates single correctors (monotherapy) and any combination of correctors (most commonly lumacaftor, tezacaftor, elexacaftor, VX-659, VX-440 or VX-152) and a potentiator (e.g. ivacaftor) (dual and triple therapies).

OBJECTIVES

To evaluate the effects of CFTR correctors (with or without potentiators) on clinically important benefits and harms in pwCF of any age with class II CFTR mutations (most commonly F508del).

SEARCH METHODS

We searched the Cochrane CF Trials Register (28 November 2022), reference lists of relevant articles and online trials registries (3 December 2022).

SELECTION CRITERIA

Randomised controlled trials (RCTs) (parallel design) comparing CFTR correctors to control in pwCF with class II mutations.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data, assessed risk of bias and judged evidence certainty (GRADE); we contacted investigators for additional data.

MAIN RESULTS

We included 34 RCTs (4781 participants), lasting between 1 day and 48 weeks; an extension of two lumacaftor-ivacaftor studies provided additional 96-week safety data (1029 participants). We assessed eight monotherapy RCTs (344 participants) (4PBA, CPX, lumacaftor, cavosonstat and FDL169), 16 dual-therapy RCTs (2627 participants) (lumacaftor-ivacaftor or tezacaftor-ivacaftor) and 11 triple-therapy RCTs (1804 participants) (elexacaftor-tezacaftor-ivacaftor/deutivacaftor; VX-659-tezacaftor-ivacaftor/deutivacaftor; VX-440-tezacaftor-ivacaftor; VX-152-tezacaftor-ivacaftor). Participants in 21 RCTs had the genotype F508del/F508del, in seven RCTs they had F508del/minimal function (MF), in one RCT F508del/gating genotypes, in one RCT either F508del/F508del genotypes or F508del/residual function genotypes, in one RCT either F508del/gating or F508del/residual function genotypes, and in three RCTs either F508del/F508del genotypes or F508del/MF genotypes. Risk of bias judgements varied across different comparisons. Results from 16 RCTs may not be applicable to all pwCF due to age limits (e.g. adults only) or non-standard designs (converting from monotherapy to combination therapy). Monotherapy Investigators reported no deaths or clinically relevant improvements in quality of life (QoL). There was insufficient evidence to determine effects on lung function. No placebo-controlled monotherapy RCT demonstrated differences in mild, moderate or severe adverse effects (AEs); the clinical relevance of these events is difficult to assess due to their variety and few participants (all F508del/F508del). Dual therapy In a tezacaftor-ivacaftor group there was one death (deemed unrelated to the study drug). QoL scores (respiratory domain) favoured both lumacaftor-ivacaftor and tezacaftor-ivacaftor therapy compared to placebo at all time points (moderate-certainty evidence). At six months, relative change in forced expiratory volume in one second (FEV1) % predicted improved with all dual combination therapies compared to placebo (high- to moderate-certainty evidence). More pwCF reported early transient breathlessness with lumacaftor-ivacaftor (odds ratio (OR) 2.05, 99% confidence interval (CI) 1.10 to 3.83; I2 = 0%; 2 studies, 739 participants; high-certainty evidence). Over 120 weeks (initial study period and follow-up), systolic blood pressure rose by 5.1 mmHg and diastolic blood pressure by 4.1 mmHg with twice-daily 400 mg lumacaftor-ivacaftor (80 participants). The tezacaftor-ivacaftor RCTs did not report these adverse effects. Pulmonary exacerbation rates decreased in pwCF receiving additional therapies to ivacaftor compared to placebo (all moderate-certainty evidence): lumacaftor 600 mg (hazard ratio (HR) 0.70, 95% CI 0.57 to 0.87; I2 = 0%; 2 studies, 739 participants); lumacaftor 400 mg (HR 0.61, 95% CI 0.49 to 0.76; I2 = 0%; 2 studies, 740 participants); and tezacaftor (HR 0.64, 95% CI 0.46 to 0.89; 1 study, 506 participants). Triple therapy No study reported any deaths (high-certainty evidence). All other evidence was low- to moderate-certainty. QoL respiratory domain scores probably improved with triple therapy compared to control at six months (six studies). There was probably a greater relative and absolute change in FEV1 % predicted with triple therapy (four studies each across all combinations). The absolute change in FEV1 % predicted was probably greater for F508del/MF participants taking elexacaftor-tezacaftor-ivacaftor compared to placebo (mean difference 14.30, 95% CI 12.76 to 15.84; 1 study, 403 participants; moderate-certainty evidence), with similar results for other drug combinations and genotypes. There was little or no difference in adverse events between triple therapy and control (10 studies). No study reported time to next pulmonary exacerbation, but fewer F508del/F508del participants experienced a pulmonary exacerbation with elexacaftor-tezacaftor-ivacaftor at four weeks (OR 0.17, 99% CI 0.06 to 0.45; 1 study, 175 participants) and 24 weeks (OR 0.29, 95% CI 0.14 to 0.60; 1 study, 405 participants); similar results were seen across other triple therapy and genotype combinations.

AUTHORS' CONCLUSIONS

There is insufficient evidence of clinically important effects from corrector monotherapy in pwCF with F508del/F508del. Additional data in this review reduced the evidence for efficacy of dual therapy; these agents can no longer be considered as standard therapy. Their use may be appropriate in exceptional circumstances (e.g. if triple therapy is not tolerated or due to age). Both dual therapies (lumacaftor-ivacaftor, tezacaftor-ivacaftor) result in similar small improvements in QoL and respiratory function with lower pulmonary exacerbation rates. While the effect sizes for QoL and FEV1 still favour treatment, they have reduced compared to our previous findings. Lumacaftor-ivacaftor was associated with an increase in early transient shortness of breath and longer-term increases in blood pressure (not observed for tezacaftor-ivacaftor). Tezacaftor-ivacaftor has a better safety profile, although data are lacking in children under 12 years. In this population, lumacaftor-ivacaftor had an important impact on respiratory function with no apparent immediate safety concerns, but this should be balanced against the blood pressure increase and shortness of breath seen in longer-term adult data when considering lumacaftor-ivacaftor. Data from triple therapy trials demonstrate improvements in several key outcomes, including FEV1 and QoL. There is probably little or no difference in adverse events for triple therapy (elexacaftor-tezacaftor-ivacaftor/deutivacaftor; VX-659-tezacaftor-ivacaftor/deutivacaftor; VX-440-tezacaftor-ivacaftor; VX-152-tezacaftor-ivacaftor) in pwCF with one or two F508del variants aged 12 years or older (moderate-certainty evidence). Further RCTs are required in children under 12 years and those with more severe lung disease.

Human epididymis protein 4 (HE4) plasma concentration inversely correlates with the improvement of cystic fibrosis lung disease in p.Phe508del-CFTR homozygous cases treated with the CFTR modulator lumacaftor/ivacaftor combination

BACKGROUND

We previously documented that elevated HE4 plasma concentration decreased in people with CF (pwCF) bearing the p.Gly551Asp-CFTR variant in response to CFTR modulator (CFTRm) ivacaftor (IVA), and this level was inversely correlated with the FEV1% predicted values (ppFEV1). Although the effectiveness of lumacaftor (LUM)/IVA in pwCF homozygous for the p.Phe508del-CFTR variant has been evaluated, plasma biomarkers were not used to monitor treatment efficacy thus far.

METHODS

Plasma HE4 concentration was examined in 68 pwCF drawn from the PROSPECT study who were homozygous for the p.Phe508del-CFTR variant before treatment and at 1, 3, 6 and 12 months after administration of LUM/IVA therapy. Plasma HE4 was correlated with ppFEV1 using their absolute and delta values. The discriminatory power of delta HE4 was evaluated for the detection of lung function improvements based on ROC-AUC analysis and multiple regression test.

RESULTS

HE4 plasma concentration was significantly reduced below baseline following LUM/IVA administration during the entire study period. The mean change of ppFEV1 was 2.6% (95% CI, 0.6 to 4.5) by 6 months of therapy in this sub-cohort. A significant inverse correlation between delta values of HE4 and ppFEV1 was observed especially in children with CF (r=-0.7053; p<0.0001). Delta HE4 predicted a 2.6% mean change in ppFEV1 (AUC: 0.7898 [95% CI 0.6823-0.8972]; P < 0.0001) at a cut-off value of -10.7 pmol/L. Moreover, delta HE4 independently represented the likelihood of being a responder with ≥ 5% delta ppFEV1 at 6 months (OR: 0.89, 95% CI: 0.82-0.95; P = 0.001).

CONCLUSIONS

Plasma HE4 level negatively correlates with lung function improvement assessed by ppFEV1 in pwCF undergoing LUM/IVA CFTRm treatment.

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.

Delivering a New Future for People With Cystic Fibrosis

Treatment, prognosis, and quality of life for people with cystic fibrosis (CF) have improved steadily since the initial description of the disease, but most dramatically in the past decade. In 2021, the median predicted survival increased to 53 years, compared with 17 years in 1970. The recent improvement in outcomes is attributable to the advent of cystic fibrosis transmembrane regulator (CFTR) modulators, small molecules that enhance the function of defective CFTR protein. The first CFTR modulator, ivacaftor, received Food and Drug Administration approval in 2011 to treat a single CFTR variant, comprising only 4% of those affected by CF. With the demonstration of efficacy, drug approval has been expanded to other variants. Multiple CFTR modulators used in combination with ivacaftor augment efficacy and increase the number of CFTR variants amenable to therapy. Approval of elexecaftor/tezecaftor/ivacaftor in 2019 increased the number of individuals who could benefit from highly effective modulator therapy (HEMT) to ∼90% of the CF population in the United States. HEMT has been dramatically effective, with overall improvements in lung function, quality of life, nutritional status, and, in women, increased fertility. HEMT may delay the onset of other CF-related comorbidities. Although off-target effects, including hepatotoxicity, drug-drug interactions, and putative mental health issues can complicate use, modulator therapy has been generally well tolerated. Ten percent of people with CF have variants that are not amenable to modulator treatment. HEMT, despite its great cost and limited global access, has brought legitimate hope and changed the lives of a significant majority of individuals and families affected by CF in North America.

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

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

CFTR modulator therapy: transforming the landscape of clinical care in cystic fibrosis

Following discovery of the cystic fibrosis transmembrane conductance regulator (CFTR) gene in 1989 and subsequent elucidation of the varied CFTR protein abnormalities that result, a new era of cystic fibrosis management has emerged-one in which scientific principles translated from the bench to the bedside have enabled us to potentially treat the basic defect in the majority of children and adults with cystic fibrosis, with a resultant burgeoning adult cystic fibrosis population. However, the long-term effects of these therapies on the multiple manifestations of cystic fibrosis are still under investigation. Understanding the effects of modulators in populations excluded from clinical trials is also crucial. Furthermore, establishing appropriate disease measures to assess efficacy in the youngest potential trial participants and in those whose post-modulator lung function is in the typical range for people without chronic lung disease is essential for continued drug development. Finally, recognising that a health outcome gap has been created for some people and widened for others who are not eligible for, cannot tolerate, or do not have access to modulators is important.

The clinical impact of Lumacaftor-Ivacaftor on structural lung disease and lung function in children aged 6-11 with cystic fibrosis in a real-world setting

BACKGROUND

Data from clinical trials of lumacaftor-ivacaftor (LUM-IVA) demonstrate improvements in lung clearance index (LCI) but not in FEV1 in children with Cystic Fibrosis (CF) aged 6-11 years and homozygous for the Phe508del mutation. It is not known whether LUM/IVA use in children can impact the progression of structural lung disease. We sought to determine the real-world impact of LUM/IVA on lung structure and function in children aged 6-11 years.

METHODS

This real-world observational cohort study was conducted across four paediatric sites in Ireland over 24-months using spirometry-controlled CT scores and LCI as primary outcome measures. Children commencing LUM-/IVA as part of routine care were included. CT scans were manually scored with the PRAGMA CF scoring system and analysed using the automated bronchus-artery (BA) method. Secondary outcome measures included rate of change of ppFEV1, nutritional indices and exacerbations requiring hospitalisation.

RESULTS

Seventy-one participants were recruited to the study, 31 of whom had spirometry-controlled CT performed at baseline, and after one year and two years of LUM/IVA treatment. At two years there was a reduction from baseline in trapped air scores (0.13 to 0.07, p = 0.016), but an increase from baseline in the % bronchiectasis score (0.84 to 1.23, p = 0.007). There was no change in overall % disease score (2.78 to 2.25, p = 0.138). Airway lumen to pulmonary artery ratios (AlumenA ratio) were abnormal at baseline and worsened over the course of the study. In 28 participants, the mean annual change from baseline LCI2.5 (-0.055 (-0.61 to 0.50), p = 0.85) measurements over two years were not significant. Improvements from baseline in weight (0.10 (0.06 to 0.15, p < 0.0001), height (0.05 (0.02 to 0.09), p = 0.002) and BMI (0.09 (0.03 to 0.15) p = 0.005) z-scores were seen with LUM/IVA treatment. The mean annual change from baseline ppFEV1 (-2.45 (-4.44 to 2.54), p = 0.66) measurements over two years were not significant.

CONCLUSION

In a real-world setting, the use of LUM/IVA over two years in children with CF aged 6-11 resulted in improvements in air trapping on CT but worsening in bronchiectasis scores. Our results suggest that LUM/IVA use in this age group improves air trapping but does not prevent progression of bronchiectasis over two years of treatment.

Effects of Lumacaftor/Ivacaftor on Cystic Fibrosis Disease Progression in Children 2 through 5 Years of Age Homozygous for F508del-CFTR: A Phase 2 Placebo-controlled Clinical Trial

Rationale: Lumacaftor/ivacaftor (LUM/IVA) was shown to be safe and well tolerated in children 2 through 5 years of age with cystic fibrosis (CF) homozygous for F508del-CFTR in a Phase 3 open-label study. Improvements in sweat chloride concentration, markers of pancreatic function, and lung clearance index2.5 (LCI2.5), along with increases in growth parameters, suggested the potential for early disease modification with LUM/IVA treatment. Objective: To further assess the effects of LUM/IVA on CF disease progression in children 2 through 5 years of age using chest magnetic resonance imaging (MRI). Methods: This Phase 2 study had two parts: a 48-week, randomized, double-blind, placebo-controlled treatment period in which children 2 through 5 years of age with CF homozygous for F508del-CFTR received either LUM/IVA or placebo (Part 1) followed by an open-label period in which all children received LUM/IVA for an additional 48 weeks (Part 2). The results from Part 1 are reported. The primary endpoint was absolute change from baseline in chest MRI global score at Week 48. Secondary endpoints included absolute change in LCI2.5 through Week 48 and absolute changes in weight-for-age, stature-for-age, and body mass index-for-age z-scores at Week 48. Additional endpoints included absolute changes in sweat chloride concentration, fecal elastase-1 levels, serum immunoreactive trypsinogen, and fecal calprotectin through Week 48. The primary endpoint was analyzed using Bayesian methods, where the actual Bayesian posterior probability of LUM/IVA being superior to placebo in the chest MRI global score at Week 48 was calculated using a vague normal prior distribution; secondary and additional endpoints were analyzed using descriptive summary statistics. Results: Fifty-one children were enrolled and received LUM/IVA (n = 35) or placebo (n = 16). For the change in chest MRI global score at Week 48, the Bayesian posterior probability of LUM/IVA being better than placebo (treatment difference, <0; higher score indicates greater abnormality) was 76%; the mean treatment difference was -1.5 (95% credible interval, -5.5 to 2.6). Treatment with LUM/IVA also led to within-group numerical improvements in LCI2.5, growth parameters, and biomarkers of pancreatic function as well as greater decreases in sweat chloride concentration compared with placebo from baseline through Week 48. Safety data were consistent with the established safety profile of LUM/IVA. Conclusions: This placebo-controlled study suggests the potential for early disease modification with LUM/IVA treatment, including that assessed by chest MRI, in children as young as 2 years of age. Clinical trial registered with www.clinicaltrials.gov (NCT03625466).

Cystic Fibrosis: A Review

Importance

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

Observations

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

Conclusion

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

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

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

Real-life impact of highly effective CFTR modulator therapy in children with cystic fibrosis

Introduction: Recently, cystic fibrosis transmembrane regulator modulator therapy with elexacaftor/tezacaftor/ivacaftor has become available for children with cystic fibrosis (CF) carrying at least one F508del mutation. Objective: To assess the intermediate term effects of elexacaftor/tezacaftor/ivacaftor in children with cystic fibrosis in a real-world setting. Methods: We performed a retrospective analysis of records of children with cystic fibrosis, who started elexacaftor/tezacaftor/ivacaftor between 8/2020 and 10/2022. Pulmonary function tests, nutritional status, sweat chloride and laboratory data were assessed before, 3 and 6 months after the start of elexacaftor/tezacaftor/ivacaftor respectively. Results: Elexacaftor/tezacaftor/ivacaftor was started in 22 children 6-11 years and in 24 children 12-17 years. Twenty-seven (59%) patients were homozygous for F508del (F/F) and 23 (50%) patients were transitioned from ivacaftor/lumacaftor (IVA/LUM) or tezacaftor/ivacaftor (TEZ/IVA) to elexacaftor/tezacaftor/ivacaftor. Overall, mean sweat chloride concentration decreased by 59.3 mmol/L (95% confidence interval: -65.0 to -53.7 mmol/L, p < 0.0001) under elexacaftor/tezacaftor/ivacaftor. Sweat chloride concentration also decreased significantly after transition from IVA/LUM or TEZ/IVA to elexacaftor/tezacaftor/ivacaftor (-47.8 mmol/l; 95% confidence interval: -57.6 to -37.8 mmol/l, n = 14, p < 0.0001). Sweat chloride reduction was more marked in children with the F/F than in those with the F/MF genotype (69.4 vs 45.9 mmol/L, p < 0.0001). At 3 months follow-up, body-mass-index-z-score increased by 0.31 (95% CI, 0.2-0.42, p < 0.0001) with no further increase at 6 months. BMI-for-age-z-score was more markedly improved in the older group. Overall pulmonary function (percent predicted FEV₁) at 3 months follow-up increased by 11.4% (95% CI: 8.0-14.9, p < 0.0001) with no further significant change after 6 months. No significant differences were noted between the age groups. Children with the F/MF genotype had a greater benefit regarding nutritional status and pulmonary function tests than those with the F/F genotype. Adverse events led to elexacaftor/tezacaftor/ivacaftor dose reduction in three cases and a temporary interruption of therapy in four cases. Conclusion: In a real-world setting, elexacaftor/tezacaftor/ivacaftor therapy had beneficial clinical effects and a good safety profile in eligible children with cystic fibrosis comparable to previously published data from controlled clinical trials. The positive impact on pulmonary function tests and nutritional status seen after 3 months of elexacaftor/tezacaftor/ivacaftor therapy was sustained at 6 months follow-up.

Early and sustained improvements of lung clearance index from two to sixteen weeks of elexacaftor/tezacaftor/ivacaftor therapy in patients with cystic fibrosis—a real world study

Since the introduction of CFTR modulator therapies, longitudinal real-life data of lung clearance index (LCI) during treatment is scarce. In this single-centre, post-approval setting, we report data of 51 patients with different stages of lung disease, age 2–52 years with repeated measurements of forced expiratory volume as a percentage of the predicted value (ppFEV₁) and LCI after 2, 4, and 16 weeks of CFTR modulator treatment and at baseline. In 25 patients during elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) treatment, significant improvements of LCI (median −1.4) and ppFEV₁ (median +8.3%) were observed after only 2 weeks, and were maintained after 4 and 16 weeks of treatment (LCI: -2.0, −2.2; ppFEV₁: +7.2%, +11.8%). We observed a significant correlation between LCI improvement at week 16 and lower baseline LCI. In 26 younger and healthier patients receiving lumacaftor/ivacaftor (LUM/IVA) treatment, no significant changes of LCI and ppFEV₁ occured. With ELX/TEZ/IVA, our data shows rapid, significant improvements of LCI and ppFEV₁ already after 2 weeks. Early LCI measurements can help to assess the patient’s response to this high-cost therapy.

Elexacaftor-Tezacaftor-Ivacaftor: A Life-Changing Triple Combination of CFTR Modulator Drugs for Cystic Fibrosis

Cystic fibrosis (CF) is a potentially fatal monogenic disease that causes a progressive multisystemic pathology. Over the last decade, the introduction of CF transmembrane conductance regulator (CFTR) modulator drugs into clinical practice has profoundly modified the lives of many people with CF (PwCF) by targeting the fundamental cause of the disease. These drugs consist of the potentiator ivacaftor (VX-770) and the correctors lumacaftor (VX-809), tezacaftor (VX-661), and elexacaftor (VX-445). In particular, the triple combination of CFTR modulators composed of elexacaftor, tezacaftor, and ivacaftor (ETI) represents a life-changing therapy for the majority of PwCF worldwide. A growing number of clinical studies have demonstrated the safety and efficacy of ETI therapy in both short- and long-term (up to two years of follow-up to date) and its ability to significantly reduce pulmonary and gastrointestinal manifestations, sweat chloride concentration, exocrine pancreatic dysfunction, and infertility/subfertility, among other disease signs and symptoms. Nevertheless, ETI therapy-related adverse effects have also been reported, and close monitoring by a multidisciplinary healthcare team remains vital. This review aims to address and discuss the major therapeutic benefits and adverse effects reported by the clinical use of ETI therapy for PwCF.

Nutritional Status and Circulating Levels of Fat-Soluble Vitamins in Cystic Fibrosis Patients: A Cohort Study and Evaluation of the Effect of CFTR Modulators

BACKGROUND

Improved therapy in CF has led to an overall improvement in nutritional status. The objectives of our study are: to cross-sectionally assess nutritional status and serum levels of fat-soluble vitamins; to retrospectively evaluate the efficacy of modulators on nutritional status and fat-soluble vitamin levels.

METHODS

In patients younger than 2 years of age, we evaluated growth, in patients aged 2-18 years, we assessed BMI z-scores, and in adults, we assessed absolute BMI values. Levels of 25(OH)D, vitamins A, and E were measured.

RESULTS

A cross-sectional analysis was conducted on 318 patients, 109 (34.3%) with pancreatic sufficiency. Only three patients were under 2 years old. In 135 patients aged 2-18 years, the median BMI z-score was 0.11, and 5 (3.7%) patients had malnutrition (z-score ≤ 2SD). In 180 adults, the median BMI was 21.8 kg/m². Overall, 15 (13.7%) males (M) and 18 (25.3%) females (F) were underweight (18 < BMI > 20); 3 (2.7%) M and 5 (7.0%) F had a BMI < 18. Suboptimal 25(OH)D levels were found in patients with pancreatic insufficiency. The prevalence of deficiency of vitamins A and E is low. After one year of treatment with modulators, the increase in BMI was more consistent (M: 1.58 ± 1.25 kg/m² F: 1.77 ± 1.21 kg/m²) in elexacaftor/tezacaftor/ivacaftor (ETI)-treated patients compared with other modulators, with a significant increase in levels of all fat-soluble vitamins.

CONCLUSIONS

Malnutrition is present in a limited number of subjects. The prevalence of subjects with suboptimal 25(OH)D levels is high. ETI showed a beneficial effect on nutritional status and circulating levels of fat-soluble vitamins.

Current and Future Therapeutic Approaches of Exocrine Pancreatic Insufficiency in Children with Cystic Fibrosis in the Era of Personalized Medicine

This review presents current updates of pancreatic enzyme replacement therapy in children with cystic fibrosis based on literature published in the last decade and some special considerations regarding pancreatic enzyme replacement therapy in the era of new therapies, such as cystic fibrosis transmembrane conductance regulator modulator therapies. Few articles evaluate the efficacy of pancreatic enzyme replacement therapy in the pediatric population, and most studies also included children and adults with cystic fibrosis. Approximately 85% of cystic fibrosis patients have exocrine pancreatic insufficiency and need pancreatic enzyme replacement therapy. Fecal elastase is the most commonly used diagnostic test for exocrine pancreatic insufficiency, although this value can fluctuate over time. While it is used as a diagnostic test, it cannot be used for monitoring the effectiveness of pancreatic enzyme replacement therapy and for adjusting doses. Pancreatic enzyme replacement therapy, the actual treatment for exocrine pancreatic insufficiency, is essential in children with cystic fibrosis to prevent malabsorption and malnutrition and needs to be urgently initiated. This therapy presents many considerations for physicians, patients, and their families, including types and timing of administration, dose monitoring, and therapy failures. Based on clinical trials, pancreatic enzyme replacement therapy is considered effective and well-tolerated in children with cystic fibrosis. An important key point in cystic fibrosis treatment is the recent hypothesis that cystic fibrosis transmembrane conductance regulator modulators could improve pancreatic function, further studies being essential. Pancreatic enzyme replacement therapy is addressed a complication of the disease (exocrine pancreatic insufficiency), while modulators target the defective cystic fibrosis transmembrane conductance regulator protein. Exocrine pancreatic insufficiency in cystic fibrosis remains an active area of research in this era of cystic fibrosis transmembrane conductance regulator modulator therapies. This new therapy could represent an example of personalized medicine in cystic fibrosis patients, with each class of modulators being addressed to patients with specific genetic mutations.

The effect of CFTR modulators on structural lung disease in cystic fibrosis

Background: Newly developed quantitative chest computed tomography (CT) outcomes designed specifically to assess structural abnormalities related to cystic fibrosis (CF) lung disease are now available. CFTR modulators potentially can reduce some structural lung abnormalities. We aimed to investigate the effect of CFTR modulators on structural lung disease progression using different quantitative CT analysis methods specific for people with CF (PwCF). Methods: PwCF with a gating mutation (Ivacaftor) or two Phe508del alleles (lumacaftor-ivacaftor) provided clinical data and underwent chest CT scans. Chest CTs were performed before and after initiation of CFTR modulator treatment. Structural lung abnormalities on CT were assessed using the Perth Rotterdam Annotated Grid Morphometric Analysis for CF (PRAGMA-CF), airway-artery dimensions (AA), and CF-CT methods. Lung disease progression (0-3 years) in exposed and matched unexposed subjects was compared using analysis of covariance. To investigate the effect of treatment in early lung disease, subgroup analyses were performed on data of children and adolescents aged <18 years. Results: We included 16 modulator exposed PwCF and 25 unexposed PwCF. Median (range) age at the baseline visit was 12.55 (4.25-36.49) years and 8.34 (3.47-38.29) years, respectively. The change in PRAGMA-CF %Airway disease (-2.88 (-4.46, -1.30), p = 0.001) and %Bronchiectasis extent (-2.07 (-3.13, -1.02), p < 0.001) improved in exposed PwCF compared to unexposed. Subgroup analysis of paediatric data showed that only PRAGMA-CF %Bronchiectasis (-0.88 (-1.70, -0.07), p = 0.035) improved in exposed PwCF compared to unexposed. Conclusion: In this preliminary real-life retrospective study CFTR modulators improve several quantitative CT outcomes. A follow-up study with a large cohort and standardization of CT scanning is needed to confirm our findings.

Cystic fibrosis related diabetes (CFRD) in the era of modulators: A scoping review

Cystic fibrosis-related diabetes (CFRD) is a common complication of CF that increases in incidence as patients age. Poor glycemic control has been shown to negatively impact lung function and weight, resulting in higher risk of recurrent pulmonary exacerbations. With the advent of highly effective modulator therapies (HEMT), patients with CF are living longer and healthier lives. Consequently, CFRD and its microvascular complications are rising in prominence, becoming one of the most urgent clinical concerns. As HEMT were developed with the primary focus of improving pulmonary outcomes, it is not clear from the original phase III studies what the short- or long-term benefits of modulators might be on CFRD development and trajectory. In this review, we will examine the pathophysiology of CFRD, summarize and synthesize the available evidence of HEMT impact on CFRD and describe the emerging research needs in this field.

Efficacy and Safety of Elexacaftor/Tezacaftor/Ivacaftor in Children 6 Through 11 Years of Age with Cystic Fibrosis Heterozygous for F508del and a Minimal Function Mutation: A Phase 3b, Randomized, Placebo-controlled Study

Rationale: The triple-combination regimen elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) was shown to be safe and efficacious in children aged 6 through 11 years with cystic fibrosis and at least one F508del-CFTR allele in a phase 3, open-label, single-arm study. Objectives: To further evaluate the efficacy and safety of ELX/TEZ/IVA in children 6 through 11 years of age with cystic fibrosis heterozygous for F508del and a minimal function CFTR mutation (F/MF genotypes) in a randomized, double-blind, placebo-controlled phase 3b trial. Methods: Children were randomized to receive either ELX/TEZ/IVA (n = 60) or placebo (n = 61) during a 24-week treatment period. The dose of ELX/TEZ/IVA administered was based on weight at screening, with children <30 kg receiving ELX 100 mg once daily, TEZ 50 mg once daily, and IVA 75 mg every 12 hours, and children ⩾30 kg receiving ELX 200 mg once daily, TEZ 100 mg once daily, and IVA 150 mg every 12 hours (adult dose). Measurements and Main Results: The primary endpoint was absolute change in lung clearance index_2.5 from baseline through Week 24. Children given ELX/TEZ/IVA had a mean decrease in lung clearance index_2.5 of 2.29 units (95% confidence interval [CI], 1.97-2.60) compared with 0.02 units (95% CI, -0.29 to 0.34) in children given placebo (between-group treatment difference, -2.26 units; 95% CI, -2.71 to -1.81; P < 0.0001). ELX/TEZ/IVA treatment also led to improvements in the secondary endpoint of sweat chloride concentration (between-group treatment difference, -51.2 mmol/L; 95% CI, -55.3 to -47.1) and in the other endpoints of percent predicted FEV₁ (between-group treatment difference, 11.0 percentage points; 95% CI, 6.9-15.1) and Cystic Fibrosis Questionnaire-Revised Respiratory domain score (between-group treatment difference, 5.5 points; 95% CI, 1.0-10.0) compared with placebo from baseline through Week 24. The most common adverse events in children receiving ELX/TEZ/IVA were headache and cough (30.0% and 23.3%, respectively); most adverse events were mild or moderate in severity. Conclusions: In this first randomized, controlled study of a cystic fibrosis transmembrane conductance regulator modulator conducted in children 6 through 11 years of age with F/MF genotypes, ELX/TEZ/IVA treatment led to significant improvements in lung function, as well as robust improvements in respiratory symptoms and cystic fibrosis transmembrane conductance regulator function. ELX/TEZ/IVA was generally safe and well tolerated in this pediatric population with no new safety findings.

Multi-target direct-acting SARS-CoV-2 antivirals against the nucleotide-binding pockets of virus-specific proteins

The nucleotide-binding pockets (NBPs) in virus-specific proteins have proven to be the most successful antiviral targets for several viral diseases. Functionally important NBPs are found in various structural and non-structural proteins of SARS-CoV-2. In this study, the first successful multi-targeting attempt to identify effective antivirals has been made against NBPs in nsp12, nsp13, nsp14, nsp15, nsp16, and nucleocapsid (N) proteins of SARS-CoV-2. A structure-based drug repurposing in silico screening approach with ADME analysis identified small molecules targeting NBPs in SARS-CoV-2 proteins. Further, isothermal titration calorimetry (ITC) experiments validated the binding of top hit molecules to the purified N-protein. Importantly, cell-based antiviral assays revealed antiviral potency for INCB28060, darglitazone, and columbianadin with EC50 values 15.71 μM, 5.36 μM, and 22.52 μM, respectively. These effective antivirals targeting multiple proteins are envisioned to direct the development of antiviral therapy against SARS-CoV-2 and its emerging variants.

Profiling the response to lumacaftor-ivacaftor in children with cystic between fibrosis and new insight from a French-Italian real-life cohort

INTRODUCTION

Clinical trials for CFTR modulators consider mean changes of clinical status at the cohort level, and thus fail to assess the heterogeneity of the response. We aimed to study the different response profiles to lumacaftor-ivacaftor according to age in children with cystic fibrosis (CF).

METHODS

A mathematical framework, including principal component analysis, data clustering, and data completion, was applied to a multicenter cohort of 112 children aged 6-18 years, treated with lumacaftor-ivacaftor. Studied parameters at baseline and 6 months included body mass index (BMI), number of days of antibiotics (ATB), Sweat test (ST), forced expiratory volume in 1 s expressed in percentage predicted (ppFEV₁ ), forced vital capacity (ppFVC), and forced expiratory flow at 25%-75% of FVC (ppFEF_25-75 ).

RESULTS

Change in ppFEV₁ was the most significant parameter in characterizing response heterogeneity among the 12-18-year-old patients. Patients with minimal changes in ppFEV₁ were further separated by change in BMI and ATB course. In the 6-12-year-old children both BMI and ppFEV₁ evolution were the most relevant. ST change was not associated with a clinical response.

CONCLUSIONS

Change in ppFEV₁ , BMI, and ATB course are the most relevant outcomes to discriminate clinical response profiles in children treated with lumacaftor-ivacaftor. Prepubertal and pubertal children display different response profiles.

Effect of Dornase Alfa on the Lung Clearance Index in Children with Cystic Fibrosis: A Lesson from a Case Series

BACKGROUND

Dornase alfa (DNase) is the only mucus-degrading agent that has proven efficacy in cystic fibrosis (CF). Few studies have evaluated the effects of DNase on the lung clearance index (LCI). We report the experience of two CF centers in which LCI monitoring was used to evaluate the efficacy of DNase therapy.

METHODS

This is a prospective and observational study, evaluating the effects of DNase therapy on LCI values in three CF children followed at CF centers in Florence and Catania, Italy. In both centers, LCI was performed routinely, every 3-6 months, based on the clinical picture and severity of the lung disease. In this study, we evaluated the LCI before and after long-term DNase therapy.

RESULTS

DNase improved LCI values in the absence of respiratory exacerbations: in case n. 1 LCI decreased by 39% in 16 months (from 11.1 to 6.8); in case n. 2 by 20% in 12 months (from 9.3 to 7.4); in case n. 3 by 24% in 16 months (from 9.3 to 7.0).

CONCLUSIONS

This case series confirms the efficacy of DNase therapy in CF children, as demonstrated by the LCI reduction in treated patients. Furthermore, our results suggest that LCI is a sensitive marker of disease and can be used for the evaluation of response to treatment.

Defining and identifying early-onset lung disease in cystic fibrosis with cumulative clinical characteristics

BACKGROUND

Because of the heterogeneity in cystic fibrosis (CF) lung disease among young children, a clinical method to identify early-onset lung disease is needed.

OBJECTIVE

To develop a CF early-onset lung disease (CFELD) scoring system by utilizing prospectively collected longitudinal data on manifestations in the first 3 years of life.

DESIGN

We studied 145 infants born during 2012-2017, diagnosed through newborn screening by age 3 months, and followed to 36 months of age. Cough severity, pulmonary exacerbations (PEx), respiratory cultures, and hospitalizations were collected at each CF center visit (every 1-2 months in infancy and quarterly thereafter). These data were used to construct the CFELD system and to classify lung disease into five categories: asymptomatic, minimal, mild, moderate, and severe.

RESULTS

The most frequent manifestation of CF early lung disease was MD-reported PEx episodes, PEx hospitalizations, and positive Pseudomonas aeruginosa cultures. Parent-reported cough severity was correlated with the number of respiratory hospitalizations (r = 0.48, p < 0.0001). The distribution of CFELD categories was 10% asymptomatic, 17% minimal, 29% mild, 33% moderate, and 12% severe. The moderate and severe categories occurred threefold higher in pancreatic insufficient (PI, 49%) versus sufficient subjects (16%), p < 0.0001. In addition to PI, gastrointestinal and nutrition-related hospitalizations, plasma cytokines interleukin (IL)-6 and IL-10, duration of CFTR modulator therapy, and type of health insurance were significant predictors of CFELD scores.

CONCLUSION

The CFELD scoring system is novel, allows systematic evaluation of lung disease prognosis early, and may aid in therapeutic decision-making particularly in the initiation of CFTR modulator therapy.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

CFTR Modulators in People with Cystic Fibrosis: Real-World Evidence in France

Cystic fibrosis (CF) is a rare genetic multisystemic disease, the manifestations of which are due to mutations in the gene encoding the CF transmembrane conductance regulator (CFTR) protein and can lead to respiratory insufficiency and premature death. CFTR modulators, which were developed in the past decade, partially restore CFTR protein function. Their clinical efficacy has been demonstrated in phase 3 clinical trials, particularly in terms of lung function and pulmonary exacerbations, nutritional status, and quality of life in people with gating mutations (ivacaftor), homozygous for the F508del mutation (lumacaftor/ivacaftor and tezacaftor/ivacaftor), and in those with at least one F508del mutation (elexacaftor/tezacaftor/ivacaftor). However, many questions remain regarding their long-term safety and effectiveness, particularly in patients with advanced lung disease, liver disease, renal insufficiency, or problematic bacterial colonization. The impact of CFTR modulators on other important outcomes such as concurrent treatments, lung transplantation, chest imaging, or pregnancies also warrants further investigation. The French CF Reference Network includes 47 CF centers that contribute patient data to the comprehensive French CF Registry and have conducted nationwide real-world studies on CFTR modulators. This review seeks to summarize the results of these real-world studies and examine their findings against those of randomized control trials.

Effects of Elexacaftor/Tezacaftor/Ivacaftor Therapy on Lung Clearance Index and Magnetic Resonance Imaging in Patients with Cystic Fibrosis and One or Two F508del Alleles

RATIONALE

We recently demonstrated that triple combination CFTR modulator therapy with elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) improves CFTR function in airway and intestinal epithelia to 40 to 50% of normal in patients with cystic fibrosis (CF) with one or two F508del alleles. In previous studies, this improvement of CFTR function was shown to improve clinical outcomes, however, effects on the lung clearance index (LCI) determined by multiple breath washout and abnormalities in lung morphology and perfusion detected by magnetic resonance imaging (MRI) have not been studied.

OBJECTIVES

To examine the effect of ELX/TEZ/IVA on LCI and lung MRI scores in patients with CF and one or two F508del alleles aged 12 years and older.

METHODS

This prospective, observational, multicenter, post-approval study assessed LCI and lung MRI scores before and 8-16 weeks after initiation of ELX/TEZ/IVA.

MEASUREMENTS AND MAIN RESULTS

A total of 91 patients with CF including 45 heterozygous for F508del and a minimal function mutation (MF) and 46 homozygous for F508del were enrolled in this study. Treatment with ELX/TEZ/IVA improved LCI in F508del/MF (-2.4;IQR, -3.7 - -1.1;P<0.001) and F508del homozygous (-1.4;IQR, -2.4 - -0.4;P<0.001) patients. Further, ELX/TEZ/IVA improved the MRI global score in F508del/MF (-6.0;IQR, -11.0 - -1.3;P<0.001) and F508del homozygous (-6.5;IQR, -11.0 - -1.3;P<0.001) patients.

CONCLUSIONS

Our data demonstrate that improvement of CFTR function by ELX/TEZ/IVA improves lung ventilation and abnormalities in lung morphology including airway mucus plugging and wall thickening in adolescent and adult patients with CF and one or two F508del alleles in a real-world, post-approval setting.

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

Background

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

Results

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

Conclusions

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

Supplementary Information

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

Medical interventions for chronic rhinosinusitis in cystic fibrosis

BACKGROUND

Chronic rhinosinusitis frequently occurs in people with cystic fibrosis. Several medical interventions are available for treating chronic rhinosinusitis in people with cystic fibrosis; for example, different concentrations of nasal saline irrigations, topical or oral corticosteroids, antibiotics - including nebulized antibiotics - dornase alfa and modulators of the cystic fibrosis transmembrane conductance regulator (CFTR) (such as lumacaftor, ivacaftor or tezacaftor). However, the efficacy of these interventions is unclear. This is an update of a previously published review.

OBJECTIVES

The objective of this review is to compare the effects of different medical interventions in people diagnosed with cystic fibrosis and chronic rhinosinusitis.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and hand searching of journals and conference abstract books. Date of last search of trials register: 09 September 2021. We also searched ongoing trials databases, other medical databases and the reference lists of relevant articles and reviews. Date of latest additional searches: 22 November 2021.

SELECTION CRITERIA

Randomized and quasi-randomized trials of different medical interventions compared to each other or to no intervention or to placebo.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials identified for potential inclusion in the review. We planned to conduct data collection and analysis in accordance with Cochrane methods and to independently rate the quality of the evidence for each outcome using the GRADE guidelines.

MAIN RESULTS

We identified no trials that met the pre-defined inclusion criteria. The most recent searches identified 44 new references, none of which were eligible for inclusion in the current version of this review; 12 studies are listed as excluded and one as ongoing.

AUTHORS' CONCLUSIONS

We identified no eligible trials assessing the medical interventions in people with cystic fibrosis and chronic rhinosinusitis. High-quality trials are needed which should assess the efficacy of different treatment options detailed above for managing chronic rhinosinusitis, preventing pulmonary exacerbations and improving quality of life in people with cystic fibrosis.

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

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

Proteostasis Regulators in Cystic Fibrosis: Current Development and Future Perspectives

In cystic fibrosis (CF), the deletion of phenylalanine 508 (F508del) in the CF transmembrane conductance regulator (CFTR) leads to misfolding and premature degradation of the mutant protein. These defects can be targeted with pharmacological agents named potentiators and correctors. During the past years, several efforts have been devoted to develop and approve new effective molecules. However, their clinical use remains limited, as they fail to fully restore F508del-CFTR biological function. Indeed, the search for CFTR correctors with different and additive mechanisms has recently increased. Among them, drugs that modulate the CFTR proteostasis environment are particularly attractive to enhance therapy effectiveness further. This Perspective focuses on reviewing the recent progress in discovering CFTR proteostasis regulators, mainly describing the design, chemical structure, and structure-activity relationships. The opportunities, challenges, and future directions in this emerging and promising field of research are discussed, as well.

Lung clearance index to characterize clinical phenotypes of children and adolescents with cystic fibrosis

Background

Lung clearance index (LCI) is accepted as an early marker of lung disease in cystic fibrosis (CF), however the utility of LCI to identify subgroups of CF disease in the paediatric age group has never been explored. The aim of the study was to characterize phenotypes of children with CF using LCI as a marker of ventilation inhomogeneity and to investigate whether these phenotypes distinguished patients based on time to pulmonary exacerbation (PE).

Methods

Data were collected on patients with CF aged < 18 years old, attending the CF Center of Milan during outpatient follow-up visits between October 2014 and September 2019. Cluster analysis using agglomerative nesting hierarchical method was performed to generate distinct phenotypes. Time-to-recurrent event analysis investigated association of phenotypes with PE.

Results

We collected 313 multiple breath washout tests on 125 children aged 5.5–16.8 years. Cluster analysis identified two divergent phenotypes in children and adolescents of same age, presenting with almost normal FEV₁ but with substantial difference in markers of ventilation inhomogeneity (mean LCI difference of 3.4, 95% Confidence Interval [CI] 2.6–4.2). A less severe phenotype was associated with a lower risk of PE relapse (Hazard Ratio 0.45, 95% CI 0.34–0.62).

Conclusions

LCI is useful in clinical practice to characterize distinct phenotypes of children and adolescents with mild/normal FEV₁. A less severe phenotype translates into a lower risk of PE relapse.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01903-5.

The effect of O2 and CO2 cross-sensitivity sensor error in the Eco Medics Exhalyzer D device on measures of conductive and acinar airway function

Introduction

The multiple breath nitrogen washout (MBNW) test provides important clinical information in obstructive airways diseases. Recently, a significant cross-sensitivity error in the O₂ and CO₂ sensors of a widely used commercial MBNW device (Exhalyzer D, Eco Medics AG, Duernten, Switzerland) was detected, which leads to overestimation of N₂ concentrations. Significant errors in functional residual capacity (FRC) and lung clearance index (LCI) have been reported in infants and children. This study investigated the impact in adults, and on additional important indices reflecting conductive (S_cond) and acinar (S_acin) ventilation heterogeneity, in health and disease.

Methods

Existing MBNW measurements of 27 healthy volunteers, 20 participants with asthma and 16 smokers were reanalysed using SPIROWARE V 3.3.1, which incorporates an error correction algorithm. Uncorrected and corrected indices were compared using paired t-tests and Bland–Altman plots.

Results

Correction of the sensor error significantly lowered FRC (mean difference 9%) and LCI (8–10%) across all three groups. S_cond was higher following correction (11%, 14% and 36% in health, asthma and smokers, respectively) with significant proportional bias. S_acin was significantly lower following correction in the asthma and smoker groups, but the effect was small (2–5%) and with no proportional bias.

Discussion

The O₂ and CO₂ cross-sensitivity sensor error significantly overestimated FRC and LCI in adults, consistent with data in infants and children. There was a high degree of underestimation of S_cond but minimal impact on S_acin. The presence of significant proportional bias indicates that previous studies will require reanalysis to confirm previous findings and to allow comparability with future studies.

O₂ and CO₂ cross-sensitivity sensor error in the Exhalyzer D device significantly overestimates FRC and LCI in adults, consistent with infants and children. Importantly, there was a high degree of underestimation of S_cond, but minimal impact on S_acin.https://bit.ly/3HcH3Tp

Overweight and cystic fibrosis: An unexpected challenge

Achieving a healthy weight balance has been a central focus of care for people who have cystic fibrosis (CF). Over the years, the emphasis has primarily been on promoting weight gain to optimize pulmonary outcomes. With continued improvements in CF care, including highly effective CF modulators available for many people, the CF community is now experiencing a new challenge: addressing the concern that some people are gaining weight excessively. While at this time, we do not know to what extent overweight and obesity will affect health outcomes for people with CF, it is likely that excessive weight gain may have negative health impacts similar to those seen in the general population. In this paper, we review the history of nutritional guidelines for people with CF, as well as more recent trends toward overweight and obesity for some. A multidisciplinary approach is needed to collaboratively start the oftentimes difficult conversation regarding excessive weight gain, and to identify resources to help people achieve and maintain a healthy weight through diet, exercise, and behavioral modification.

Precision Medicine Based on CFTR Genotype for People with Cystic Fibrosis

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

Cystic fibrosis-related liver disease: Clinical presentations, diagnostic and monitoring approaches in the era of CFTR modulator therapies

Cystic fibrosis (CF) is the most common autosomal recessive disease in the Caucasian population. Cystic fibrosis-related liver disease (CFLD) is defined as the pathogenesis related to the underlying CFTR defect in biliary epithelial cells. CFLD needs to be distinguished from other liver manifestations that may not have any pathological significance. The clinical/histological presentation and severity of CFLD vary. The main histological presentation of CFLD is focal biliary fibrosis, which is usually asymptomatic. Portal hypertension develops in a minority of cases (about 10%) and may require specific management including liver transplantation for end-stage liver disease. Portal hypertension is usually the result of the progression of focal biliary fibrosis to multilobular cirrhosis during childhood. Nevertheless, non-cirrhotic portal hypertension as a result of porto-sinusoidal vascular disease is now identified increasingly more frequently, mainly in young adults. To evaluate the effect of new CFTR modulator therapies on the liver, the spectrum of hepatobiliary involvement must first be precisely classified. This paper discusses the phenotypic features of CFLD, its underlying physiopathology and relevant diagnostic and follow-up approaches, with a special focus on imaging.