Comparison of a novel potentiator of CFTR channel activity to ivacaftor in ameliorating mucostasis caused by cigarette smoke in primary human bronchial airway epithelial cells.

BACKGROUND: Cystic Fibrosis causing mutations in the gene CFTR, reduce the activity of the CFTR channel protein, and leads to mucus aggregation, airway obstruction and poor lung function. A role for CFTR in the pathogenesis of other muco-obstructive airway diseases such as Chronic Obstructive Pulmonary Disease (COPD) has been well established. The CFTR modulatory compound, Ivacaftor (VX-770), potentiates channel activity of CFTR and certain CF-causing mutations and has been shown to ameliorate mucus obstruction and improve lung function in people harbouring these CF-causing mutations. A pilot trial of Ivacaftor supported its potential efficacy for the treatment of mucus obstruction in COPD. These findings prompted the search for CFTR potentiators that are more effective in ameliorating cigarette-smoke (CS) induced mucostasis. METHODS: Small molecule potentiators, previously identified in CFTR binding studies, were tested for activity in augmenting CFTR channel activity using patch clamp electrophysiology in HEK-293 cells, a fluorescence-based assay of membrane potential in Calu-3 cells and in Ussing chamber studies of primary bronchial epithelial cultures. Addition of cigarette smoke extract (CSE) to the solutions bathing the apical surface of Calu-3 cells and primary bronchial airway cultures was used to model COPD. Confocal studies of the velocity of fluorescent microsphere movement on the apical surface of CSE exposed airway epithelial cultures, were used to assess the effect of potentiators on CFTR-mediated mucociliary movement. RESULTS: We showed that SK-POT1, like VX-770, was effective in augmenting the cyclic AMP-dependent channel activity of CFTR. SK-POT-1 enhanced CFTR channel activity in airway epithelial cells previously exposed to CSE and ameliorated mucostasis on the surface of primary airway cultures. CONCLUSION: Together, this evidence supports the further development of SK-POT1 as an intervention in the treatment of COPD.

Impact of lumacaftor/ivacaftor on the bacterial and fungal respiratory pathogens in cystic fibrosis: a prospective multicenter cohort study in Sweden.

BACKGROUND: A significant decline in pulmonary exacerbation rates has been reported in CF patients homozygous for F508del treated with lumacaftor/ivacaftor. However, it is still unclear whether this reduction reflects a diminished microbiological burden. OBJECTIVES: The aim of this study was to determine the impact of lumacaftor/ivacaftor on the bacterial and fungal burden. DESIGN: The study is a prospective multicenter cohort study including 132 CF patients homozygous for F508del treated with lumacaftor/ivacaftor. METHODS: Clinical parameters as well as bacterial and fungal outcomes 1 year after initiation of lumacaftor/ivacaftor were compared to data from 2 years prior to initiation of the treatment. Changes in the slope of the outcomes before and after the onset of treatment were assessed. RESULTS: Lung function measured as ppFEV1 (p < 0.001), body mass index (BMI) in adults (p < 0.001), and BMI z-score in children (p = 0.007) were improved after initiation of lumacaftor/ivacaftor. In addition, the slope of the prevalence of Streptococcus pneumoniae (p = 0.007) and Stenotrophomonas maltophilia (p < 0.001) shifted from positive to negative, that is, became less prevalent, 1 year after treatment, while the slope for Candida albicans (p = 0.009), Penicillium spp (p = 0.026), and Scedosporium apiospermum (p < 0.001) shifted from negative to positive. CONCLUSION: The current study showed a significant improvement in clinical parameters and a reduction of some of CF respiratory microorganisms 1 year after starting with lumacaftor/ivacaftor. However, no significant changes were observed for Pseudomonas aeruginosa, Staphylococcus aureus, or Aspergillus fumigatus, key pathogens in the CF context.

In utero and postnatal ivacaftor/lumacaftor therapy rescues multiorgan disease in CFTR-F508del ferrets.

Cystic fibrosis (CF) is caused by mutations in the CF transmembrane conductance regulator (CFTR) gene, with F508del being the most prevalent mutation. The combination of CFTR modulators (potentiator and correctors) has provided benefit to CF patients carrying the F508del mutation; however, the safety and effectiveness of in utero combination modulator therapy remains unclear. We created a F508del ferret model to test whether ivacaftor/lumacaftor (VX-770/VX-809) therapy can rescue in utero and postnatal pathologies associated with CF. Using primary intestinal organoids and air-liquid interface cultures of airway epithelia, we demonstrate that the F508del mutation in ferret CFTR results in a severe folding and trafficking defect, which can be partially restored by treatment with CFTR modulators. In utero treatment of pregnant jills with ivacaftor/lumacaftor prevented meconium ileus at birth in F508del kits and sustained postnatal treatment of CF offspring improved survival and partially protected from pancreatic insufficiency. Withdrawal of ivacaftor/lumacaftor treatment from juvenile CF ferrets reestablished pancreatic and lung diseases, with altered pulmonary mechanics. These findings suggest that in utero intervention with a combination of CFTR modulators may provide therapeutic benefits to individuals with F508del. This CFTR-F508del ferret model may be useful for testing therapies using clinically translatable endpoints.

Safety and efficacy of ivacaftor in infants aged 1 to less than 4 months with cystic fibrosis.

BACKGROUND: Ivacaftor (IVA) has been shown to be safe and efficacious in children aged ≥4 months with cystic fibrosis (CF) and CFTR gating variants. We evaluated safety, pharmacokinetics (PK), and efficacy of IVA in a small cohort of infants aged 1 to <4 months with CF. METHODS: In this phase 3, open-label study, infants 1 to <4 months with CF and an IVA-responsive CFTR variant received an initial low dose of IVA based on age and weight. Because IVA is a sensitive CYP3A substrate and CYP3A maturation is uncertain in infants, doses were adjusted at day 15 to better match median adult exposures based on individual PK measurements taken on day 4. Primary endpoints were safety and PK measurements. RESULTS: Seven infants (residual function CFTR variants [n=5]; minimal function CFTR variants [n=2]) received ≥1 dose of IVA. Six infants had doses adjusted at day 15 and one infant did not require dose adjustment; subsequent PK analyses showed mean trough concentrations for IVA and metabolites were within range of prior clinical experience. Four infants (57.1%) had adverse events (AEs); no serious AEs were noted. One infant discontinued study drug due to a non-serious AE of elevated alanine aminotransferase >8x the upper limit of normal. Mean sweat chloride concentration decreased (-40.3 mmol/L [SD: 29.2]) through week 24. Improvements in biomarkers of pancreatic function and intestinal inflammation, as well as growth parameters, were observed. CONCLUSIONS: In this small, open-label study, IVA dosing in infants achieved exposures previously shown to be safe and efficacious. Because PK was predictable, a dosing regimen based on age and weight is proposed. IVA was generally safe and well tolerated, and led to improvements in CFTR function, markers of pancreatic function and intestinal inflammation, and growth parameters, supporting use in infants as young as 1 month of age.

Multisystemic Effects of Elexacaftor-Tezacaftor-Ivacaftor in Adults with Cystic Fibrosis and Advanced Lung Disease.

Rationale: Limited data exist on the safety and effectiveness of elexacaftor-tezacaftor-ivacaftor (ETI) in people with cystic fibrosis (pwCF) and advanced lung disease. Objectives: To evaluate the effects of ETI in an unselected population of pwCF and advanced lung disease. Methods: A prospective observational study, including all adults aged 18 years and older with percentage predicted forced expiratory volume in 1 second (ppFEV1) ⩽ 40 who initiated ETI from December 2019 to June 2021 in France, was conducted. PwCF were followed until August 8, 2022. Results: ETI was initiated in 434 pwCF with a median ppFEV1 of 30 (interquartile range, 25-35), including 27 with severe cystic fibrosis liver disease and 183 with diabetes. PwCF were followed for a median of 587 (interquartile range, 396-728) days after ETI initiation. Discontinuation of ETI occurred in 12 (2.8%) pwCF and was due mostly to lung transplantation (n = 5) or death (n = 4). Absolute increase in ppFEV1 by a mean of +14.2% (95% confidence interval, 13.1-15.4%) occurred at 1 month and persisted throughout the study. Increase in ppFEV1 in the youngest age quartile was almost twice that of the oldest quartile (P < 0.001); body mass index < 18.5 kg/m2 was found in 38.6% at initiation versus 11.3% at 12 months (P = 0.0001). Increases in serum concentrations of vitamins A and E, but not 25-hydroxy vitamin D3, were observed. Significant reductions in the percentages of pwCF using oxygen therapy, noninvasive ventilation, nutritional support, and inhaled and systemic therapies (including antibiotics) were observed; insulin was discontinued in 12% of patients with diabetes. Conclusions: ETI is safe in pwCF and advanced lung disease, with multisystem pulmonary and extrapulmonary benefits.

Safety and efficacy of elexacaftor/tezacaftor/ivacaftor in people with Cystic Fibrosis following liver transplantation: A systematic review.

BACKGROUND & AIMS: Cystic Fibrosis (CF) liver disease progresses to liver failure requiring transplantation in about 3 % of patients, 0.7 % of CF patients are post liver transplant. The prognosis of CF has improved with the introduction of elexacaftor/tezacaftor/ivacaftor (ETI). Due to the paucity of data and concerns regarding interactions with immunosuppressive drug regimens, there is no general consensus on use of ETI post liver transplantation. The aim of this review is to report the safety and efficacy of ETI in CF patients who underwent liver transplantation. METHODS: A systematic review was conducted through MEDLINE/Pubmed and EMBASE databases. English-written articles reporting clinical data on liver transplanted CF patients treated with ETI were included. Article quality was evaluated using the Critical Appraisal Checklist for Case Reports. RESULTS: Twenty cases were retrieved from 6 reports. Temporary discontinuation and/or dose reduction due to elevated transaminases was required in 5 cases. ETI restarted on a reduced dose was tolerated in 3 out of 5 patients, 1 patient tolerated full dose. Tacrolimus dose change was required in 14 cases, in 1 case ETI was discontinued due to tacrolimus toxicity. Improvement in percentage predicted FEV1 was noted in 15/19 patients (median +17 %, range 8 %-38 %). CONCLUSIONS: In the majority of liver transplanted patients ETI is well tolerated, although adverse events and liver function abnormalities may occur. Close monitoring of liver function and tacrolimus level is warranted. Significant improvement in lung function after ETI initiation is confirmed, highlighting the importance of accessing this medication for this group of patients.

Predicting lung function decline in cystic fibrosis: the impact of initiating ivacaftor therapy.

BACKGROUND: Modulator therapies that seek to correct the underlying defect in cystic fibrosis (CF) have revolutionized the clinical landscape. Given the heterogeneous nature of lung disease progression in the post-modulator era, there is a need to develop prediction models that are robust to modulator uptake. METHODS: We conducted a retrospective longitudinal cohort study of the CF Foundation Patient Registry (N = 867 patients carrying the G551D mutation who were treated with ivacaftor from 2003 to 2018). The primary outcome was lung function (percent predicted forced expiratory volume in 1 s or FEV1pp). To characterize the association between ivacaftor initiation and lung function, we developed a dynamic prediction model through covariate selection of demographic and clinical characteristics. The ability of the selected model to predict a decline in lung function, clinically known as an FEV1-indicated exacerbation signal (FIES), was evaluated both at the population level and individual level. RESULTS: Based on the final model, the estimated improvement in FEV1pp after ivacaftor initiation was 4.89% predicted (95% confidence interval [CI]: 3.90 to 5.89). The rate of decline was reduced with ivacaftor initiation by 0.14% predicted/year (95% CI: 0.01 to 0.27). More frequent outpatient visits prior to study entry and being male corresponded to a higher overall FEV1pp. Pancreatic insufficiency, older age at study entry, a history of more frequent pulmonary exacerbations, lung infections, CF-related diabetes, and use of Medicaid insurance corresponded to lower FEV1pp. The model had excellent predictive accuracy for FIES events with an area under the receiver operating characteristic curve of 0.83 (95% CI: 0.83 to 0.84) for the independent testing cohort and 0.90 (95% CI: 0.89 to 0.90) for 6-month forecasting with the masked cohort. The root-mean-square errors of the FEV1pp predictions for these cohorts were 7.31% and 6.78% predicted, respectively, with standard deviations of 0.29 and 0.20. The predictive accuracy was robust across different covariate specifications. CONCLUSIONS: The methods and applications of dynamic prediction models developed using data prior to modulator uptake have the potential to inform post-modulator projections of lung function and enhance clinical surveillance in the new era of CF care.

Year in review 2023 - Back to the future.

This review synthesizes articles published in 2023, focusing on the impact of elexacaftor-tezacaftor-ivacaftor (ETI) in cystic fibrosis (CF) care. Real-world data highlights sustained benefits of ETI across age groups, while challenges like neuropsychological side effects persist. Beyond CFTR modulators, research explores telemedicine and novel therapies. Prioritizing equitable access and addressing unmet needs remain crucial for comprehensive CF management.

Alterations in the fecal microbiota in patients with advanced cystic fibrosis liver disease after 6 months of elexacaftor/tezacaftor/ivacaftor.

BACKGROUND: Cystic fibrosis associated liver disease (CFLD) carries a significant disease burden with no effective preventive therapies. According to the gut-liver axis hypothesis for CFLD pathogenesis, dysbiosis and increased intestinal inflammation and permeability permit pathogenic bacterial translocation into the portal circulation, leading to hepatic inflammation and fibrosis. Evaluating the effect of CFTR (cystic fibrosis transmembrane conductance regulator) modulation with elexacaftor/tezacaftor/ivacaftor (ETI) may help determine the role of CFTR in CFLD and increase understanding of CFLD pathogenesis, which is critical for developing therapies. We aimed to characterize the fecal microbiota in participants with CF with and without advanced CFLD (aCFLD) before and after ETI. METHODS: This is an ancillary analysis of stool samples from participants ages ≥12 y/o enrolled in PROMISE (NCT04038047). Included participants had aCFLD (cirrhosis with or without portal hypertension, or non-cirrhotic portal hypertension) or CF without liver disease (CFnoLD). Fecal microbiota were defined by shotgun metagenomic sequencing at baseline and 1 and 6 months post-ETI. RESULTS: We analyzed 93 samples from 34 participants (11 aCFLD and 23 CFnoLD). Compared to CFnoLD, aCFLD had significantly higher baseline relative abundances of potential pathogens Streptococcus salivarius and Veillonella parvula. Four of 11 aCFLD participants had an initially abnormal fecal calprotectin that normalized 6 months post-ETI, correlating with a significant decrease in S. salivarius and a trend towards decreasing V. parvula. CONCLUSIONS: These results support an association between dysbiosis and intestinal inflammation in CFLD with improvements in both post-ETI, lending further support to the gut-liver axis in aCFLD.

The effect of discontinuing hypertonic saline or dornase alfa on mucociliary clearance in elexacaftor/tezacaftor/ivacaftor treated people with cystic fibrosis: The SIMPLIFY-MCC Study.

Many people with CF (pwCF) desire a reduction in inhaled treatment burden after initiation of elexacaftor/tezacaftor/ivacaftor. The randomized, open-label SIMPLIFY study showed that discontinuing hypertonic saline (HS) or dornase alfa (DA) was non-inferior to continuation of each treatment with respect to change in lung function over a 6-week period. In this SIMPLIFY substudy, we used gamma scintigraphy to determine whether discontinuation of either HS or DA was associated with deterioration in the rate of in vivo mucociliary clearance (MCC) in participants ≥12 years of age. While no significant differences in MCC endpoints were associated with HS discontinuation, significant improvement in whole and peripheral lung MCC was observed after discontinuing DA. These results suggest that pwCF on ETI with mild lung disease do not experience a subclinical deterioration in MCC that could later impact health outcomes after discontinuing HS, and in fact may benefit from improved MCC after stopping DA treatment.

Effectiveness of lumacaftor/ivacaftor initiation in children with cystic fibrosis aged 2 through 5 years on disease progression: Interim results from an ongoing registry-based study.

BACKGROUND: Lumacaftor/ivacaftor (LUM/IVA) has been shown to be safe and efficacious in people with cystic fibrosis (CF) ≥1 year of age. To assess the impact of early LUM/IVA initiation on CF disease progression, a 6-year observational study leveraging data from existing CF patient registries is being conducted in children with CF homozygous for F508del (F/F genotype) who were aged 2 through 5 years at treatment initiation. Here we present interim results from this study focusing on data from the European CF Society Patient Registry (ECFSPR). METHODS: The LUM/IVA cohort included children in the ECFSPR who started LUM/IVA between 15 January 2019 and 31 December 2020. Longitudinal trends in growth parameters, pulmonary exacerbations, hospitalizations, safety outcomes, and other effectiveness outcomes in the LUM/IVA cohort were compared to those in two modulator-naïve cohorts: (i) matched concurrent cohort heterozygous for F508del and a minimal function mutation (F/MF concurrent comparator cohort) and (ii) matched concurrent cohort with the F/F genotype from countries without commercial access to LUM/IVA as of 2020 (F/F concurrent comparator cohort). RESULTS: The LUM/IVA cohort matched to the F/MF concurrent comparator cohort had 681 children and the LUM/IVA cohort matched to the F/F concurrent comparator cohort had 183 children. LUM/IVA cohorts had increases in body mass index percentiles relative to the matched F/MF and F/F concurrent comparator cohorts (mean difference in change from baseline: 8.4 [95% CI: 5.5, 11.3] and 11.8 [95% CI: 5.9, 17.7], respectively). Increases in height and weight percentiles were also observed in the LUM/IVA cohort relative to the F/MF and F/F concurrent comparator cohorts. Reductions in pulmonary exacerbations and hospitalizations relative to baseline and the F/F concurrent comparator cohort were seen in 2021. CONCLUSIONS: This interim analysis showed favorable trends in clinical outcomes, including growth parameters, pulmonary exacerbations, and hospitalizations, suggesting an early beneficial effect of LUM/IVA treatment in children aged 2 through 5 years at treatment initiation.

Highly effective cystic fibrosis transmembrane conductance (regulator) modulator therapy: shifting the curve for most while leaving some further behind.

PURPOSE OF REVIEW: Traditional cystic fibrosis (CF) care had been focused on early intervention and symptom mitigation. With the advent of highly effective cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapy (HEMT), in particular, the approval of elexacaftor/tezacaftor/ivacaftor in 2019, there has been a dramatic improvement in outcomes in CF. The purpose of this article is to review the benefits, limitations, and impact of HEMT as well as discuss the new implications, challenges, and hope that modulators bring to people with CF (pwCF). RECENT FINDINGS: HEMT has demonstrated sustained improvement in lung function, nutrition, quality of life, and survival for over 90% of pwCF. As HEMT has delivered such promise, there is a small but significant portion of pwCF who do not benefit from HEMT due to ineligible mutations, intolerance, or lack of accessibility to modulators. SUMMARY: HEMT has significantly improved outcomes, but continued research is needed to understand the new challenges and implications the era of HEMT will bring, as well as how to provide equitable care to those who are unable to benefit from HEMT.

Efficacy of Elexacaftor-Tezacaftor-Ivacaftor on chronic rhinosinusitis in cystic fibrosis.

PURPOSE: Our work aims to add evidence on the effectiveness of Elexacaftor-Tezacaftor-Ivacaftor on chronic rhinosinusitis in cystic fibrosis. MATERIALS AND METHODS: We conducted an observational retrospective cohort study at the Cystic Fibrosis Center of a tertiary care hospital to investigate the effect of Elexacaftor-Tezacaftor-Ivacaftor on chronic rhinosinusitis in cystic fibrosis patients, aged 12 or older. The study's endpoints were the change in the occurrence of acute exacerbations of chronic rhinosinusitis, and the variation of the endoscopic and radiologic findings scored using the Lund-Kennedy endoscopic scale, Lund-Mackay, and modified Lund-Mackay radiologic scales, in patients who underwent both pre-treatment and post-treatment examinations. RESULTS: The study population comprised 136 patients, of which 28 underwent both pre-treatment and post-treatment nasal endoscopy and 15 had pre- and post-treatment CT scans. Elexacaftor-Tezacaftor-Ivacaftor provided a significant improvement in chronic rhinosinusitis. The mean number of acute exacerbations of chronic rhinosinusitis per year in the pre-treatment time was 0.55 versus 0.35 during the treatment (p < 0.0021). The Lund-Kennedy scale had a pre-treatment average score of 4.21 points versus 1.5 points after the start of Elexacaftor-Tezacaftor-Ivacaftor (p < 0.0001). The average Lund-Mackay and modified Lund-Mackay scores in the pre-treatment time were respectively 14.6 and 16.45 points; and after the start of the therapy, they became 5.87 and 6.73 (p < 0.0001). CONCLUSION: Elexacaftor-Tezacaftor-Ivacaftor was associated with fewer acute exacerbations of chronic rhinosinusitis, and a significant improvement of chronic rhinosinusitis evaluated endoscopically and radiologically. To our knowledge, this is the first study investigating the change in the occurrence of acute exacerbation of chronic rhinosinusitis in patients affected by cystic fibrosis in therapy with Elexacaftor-Tezacaftor-Ivacaftor.

Lung clearance index (LCI2.5) changes after initiation of Elexacaftor/Tezacaftor/Ivacaftor in children with cystic fibrosis aged between 6 and 11 years: The "real-world" differs from trial data.

BACKGROUND: Elexacaftor in combination with Tezacaftor and Ivacaftor (ETI) became licensed in the United Kingdom in early 2022 for children aged 6-11 years with cystic fibrosis (CF) and an eligible mutation. Many in this age group have excellent prior lung health making quantitative measurement of benefit challenging. Clinical trials purport that lung clearance index (LCI2.5) measurement is most suitable for this purpose. OBJECTIVES: This study aimed to understand the clinical utility of LCI2.5 in detecting change after commencing ETI in the real world. PATIENT SELECTION/METHODS: Baseline anthropometric data were collected along with spirometry (forced expiratory volume in 1 s [FEV1], forced vital capacityFV and LCI2.5 measures in children aged 6-11 years with CF before starting ETI. Measures were repeated after a mean (range) of 8.2 (7-14) months of ETI treatment. The primary endpoint was a change in LCI2.5, with secondary endpoints including change in FEV1 and change in body mass index (BMI) also reported. RESULTS: Twelve children were studied (seven male, mean age 9.5 years at baseline). Our study population had a mean (SD) LCI2.5 of 7.01 (1.14) and FEV1 of 96 (13) %predicted at baseline. Mean (95% confidence interval) changes in LCI2.5 [-0.7 (-1.4, 0), p = .06] and BMI [+0.7 (+0.1, +1.3), p = .03] were observed, along with changes in FEV1 of +3.1 (-1.9, +8.1) %predicted. CONCLUSIONS: Real-world changes in LCI2.5 (-0.7) are different to those reported in clinical trials (-2.29). Lower baseline LCI2.5 as a result of prior modulator exposure, high baseline lung health, and new LCI2.5 software analyses all contribute to lower LCI2.5 values being recorded in the real world of children with CF.

Elexacaftor/tezacaftor/ivacaftor improves chronic rhinosinusitis detected by magnetic resonance imaging in children with cystic fibrosis on long-term therapy with lumacaftor/ivacaftor.

INTRODUCTION: Previous studies using magnetic resonance imaging (MRI) demonstrated early onset and progression of chronic rhinosinusitis (CRS) from infancy to school age, and response to lumacaftor/ivacaftor (LUM/IVA) therapy in children with cystic fibrosis (CF). However, the effect of elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) on CRS detected by MRI in children with CF and at least one F508del mutation, and potential incremental effects of ELX/TEZ/IVA compared to LUM/IVA in F508del homozygous children have not been studied. METHODS: 30 children with CF with at least one F508del mutation underwent three longitudinal paranasal sinus MRI before (MRI1), without (n = 16) or with LUM/IVA therapy (n = 14, MRI2), and with ELX/TEZ/IVA therapy (MRI3, mean age at therapy initiation 11.1 ± 3.4y, range 6-16y). MRI were evaluated using the CRS-MRI score. RESULTS: After therapy initiation with ELX/TEZ/IVA, the prevalence and in maxillary and sphenoid sinuses the dominance of mucopyoceles decreased (35% vs. 0 %, p<0.001 and 26% vs. 8 %, p < 0.05, respectively). This leads to a reduction in mucopyocele subscore (-3.4 ± 1.9, p < 0.001), and sinus subscores in MRI3 (maxillary sinus: -5.3 ± 3.1, p < 0.001, frontal sinus: -1.0 ± 1.9, p < 0.01, sphenoid subscore: -2.8 ± 3.5, p < 0.001, ethmoid sinus: -1.7 ± 1.9, p < 0.001). The CRS-MRI sum score decreased after therapy initiation with ELX/TEZ/IVA by -9.6 ± 5.5 score points (p < 0.001). The strength in reduction of mucopyoceles subscore and CRS-MRI sum score was independent of a pretreatment with LUM/IVA from MRI1-MRI2 (p = 0.275-0.999). CONCLUSIONS: ELX/TEZ/IVA therapy leads to improvement of CRS in eligible children with CF. Our data support the role of MRI for comprehensive monitoring of CRS disease severity and response to therapy in children with CF.

Subtherapeutic triazole concentrations as result of a drug-drug interaction with lumacaftor/ivacaftor.

Lumacaftor/ivacaftor (Orkambi®, LUM/IVA) is indicated for the treatment of cystic fibrosis (CF) patients aged ≥ 2 years with homozygous F580del mutation in the CFTR gene. Triazole fungal agents are used to treat fungal disease in CF. The use of triazoles is limited by pharmacokinetic challenges, such as drug-drug interactions. The most notable drug-drug interaction between triazoles and LUM/IVA is due to strong induction of CYP3A4 and UGT by LUM. In this real-world retrospective observational study, we described the effect of LUM/IVA on the trough concentration of triazoles. Concomitant use of LUM/IVA with itraconazole, posaconazole or voriconazole resulted in subtherapeutic triazole levels in 76% of the plasma samples. In comparison, in patients with triazole agents without LUM/IVA only 30.6% of the plasma samples resulted in subtherapeutic concentrations. Subtherapeutic plasma concentrations of triazoles should be considered in CF patients on LUM/IVA and further research is warranted for other dosing strategies and alternative antifungal therapy.