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Historically, studies show that female patients with cystic fibrosis (CF) have worse pulmonary outcomes than male patients, including decreased life expectancy. It is unknown whether this disparity persists in the new era of highly effective modulator therapies. Ivacaftor has been available in the United States for > 10 years, allowing for the opportunity to understand the impact this therapy may have on sex disparities in CF. We hypothesized that female patients will continue to show worse outcomes because we suspect that the disparity is not driven solely by ion channel dysfunction. Does a difference in outcomes between male and female patients persist after the initiation of ivacaftor in people with CF? We conducted a retrospective cohort study using the CF Foundation Patient Registry comparing changes in pulmonary exacerbation rate, lung function (FEV 1 % predicted), and presence of Pseudomonas aeruginosa among male patients vs female patients before and after initiation of treatment with the highly effective modulator ivacaftor. The cohort comprised 1,900 people with CF who were treated with ivacaftor between 2010 and 2017; 928 patients (48.84%) were male and 972 patients (51.16%) were female with a mean age of 33.09 years. Male patients showed a significant decrease in pulmonary exacerbations after ivacaftor treatment (from 0.38 to 0.34; adjusted rate ratio, 0.89; P =.028), whereas female patients did not (from 0.48 to 0.45; adjusted rate ratio, 0.95; P =.174). FEV 1 % predicted similarly decreased in both male and female patients before vs after ivacaftor treatment. P aeruginosa prevalence decreased to a similar extent in both male and female patients after ivacaftor treatment. Our findings demonstrate that sex disparities in CF persist in those treated with ivacaftor because of differences in pulmonary exacerbations. More research is needed to determine the specific pathophysiologic drivers of this disparity. [ABSTRACT FROM AUTHOR]

The document is a corrigendum for an article titled "Inhibitory effects of calcium channel blockers nisoldipine and nimodipine on ivacaftor metabolism and their underlying mechanism." The correction addresses errors in Figure 7 and Table 2 related to the unit of concentration values used. The corrected Ki values are now 3.26 and 5.87, respectively. The authors assure that these corrections do not impact the scientific conclusions of the original article. [Extracted from the article]

Ivacaftor is the first potentiator of the cystic fibrosis transmembrane conductance regulator (CFTR) protein approved for use alone in the treatment of cystic fibrosis (CF). Ivacaftor is primarily metabolized by CYP3A4 and therefore may interact with drugs that are CYP3A4 substrates, resulting in changes in plasma exposure to ivacaftor. The study determined the levels of ivacaftor and its active metabolite M1 by ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). We screened 79 drugs and 19 severely inhibited ivacaftor metabolism, particularly two cardiovascular drugs (nisoldipine and nimodipine). In rat liver microsomes (RLM) and human liver microsomes (HLM), the half-maximal inhibitory concentrations (IC50) of nisoldipine on ivacaftor metabolism were 6.55 μM and 9.10 μM, respectively, and the inhibitory mechanism of nisoldipine on ivacaftor metabolism was mixed inhibition; the IC50 of nimodipine on ivacaftor metabolism in RLM and HLM were 4.57 μM and 7.15 μM, respectively, and the inhibitory mechanism of nimodipine on ivacaftor was competitive inhibition. In pharmacokinetic experiments in rats, it was observed that both nisoldipine and nimodipine significantly altered the pharmacokinetic parameters of ivacaftor, such as AUC(0-t) and CLz/F. However, this difference may not be clinically relevant. In conclusion, this paper presented the results of studies investigating the interaction between these drugs and ivacaftor in vitro and in vivo. The objective is to provide a rationale for the safety of ivacaftor in combination with other drugs. [ABSTRACT FROM AUTHOR]

Background/Objectives: Elexacaftor, tezacaftor, and ivacaftor (ETI) have significantly improved lung function in people with cystic fibrosis (pwCF). Despite exceptional improvements in most cases, treatment-related inter-subject variability and drug–drug interactions that complicate modulator therapy have been reported. Methods: This retrospective analysis presents data on the serum concentration of ETI in our pwCF with full or reduced dosage from August 2021 to December 2023 via routine therapeutic drug monitoring (TDM). The data were compared with the maximum drug concentrations (Cmax) from the pharmaceutical company's summary of product characteristics. Results: A total of 786 blood samples from 155 pwCF (41% female, 59% male) were analyzed. The examinations were divided into four groups: full dose within the given tmax (38.5% of all measurements), full dose outside the tmax (29%), reduced dose within the tmax (19.2%), and reduced dose outside the tmax (13.2%). In pwCF receiving the full dose and blood taken within the tmax, 45.3% of serum concentrations of elexacaftor, 51.1% of serum concentrations of ivacaftor, and 8.9% of serum concentrations of tezacaftor were found to be above the Cmax, respectively. For those on reduced doses within the tmax, 24.5% had a serum concentration of elexacaftor, 23.2% had a serum concentration of ivacaftor, and 2.5% had a serum concentration of tezacaftor above the Cmax, respectively. Conclusions: Many pwCF under ETI therapy have Cmax values for elexacaftor and ivacaftor above the recommended range, even on reduced doses or before the tmax was reached. This highlights the value of a TDM program. Further pharmacokinetic studies are necessary. [ABSTRACT FROM AUTHOR]

Rationale: Pulmonary ionocytes are a newly discovered airway epithelial cell type proposed to be a major contributor to cystic fibrosis (CF) lung disease based on observations they express the cystic fibrosis transmembrane conductance regulator (CFTR) anion channel at a higher level than any other cell type in the airway epithelia. Moreover, genetically manipulated experimental models that lack ionocytes develop NaCl transport abnormalities and airway surface liquid (ASL) dehydration consistent with CF. However, no direct evidence indicates ionocytes engage in NaCl transport or contribute to ASL formation, questioning the relevance of ionocytes to CF lung disease. Objectives: To determine the ion transport properties of pulmonary ionocytes and club cells in genetically intact healthy and CF airway epithelia. Methods: We measured ion transport at the single-cell level using a self-referencing ion-selective microelectrode technique in primary human bronchial epithelial cell culture. Measurements and Main Results: cAMP-stimulated non-CF ionocytes do not secrete Na+ or Cl− into the ASL, but rather modulate its pH by secreting bicarbonate via CFTR-linked Cl−/bicarbonate exchange. Non-CF club cells secrete Na+ and Cl− to the lumen side after cAMP stimulation. CF ionocytes and club cells do not transport ions in response to cAMP stimulation, but incubation with CFTR modulators elexacaftor/tezacaftor/ivacaftor restores transport properties. Conclusions: We conclude that ionocytes do not contribute to ASL formation but regulate ASL pH. Club cells secrete the bulk of airway fluid. In CF, abnormal ionocyte and club cell function results in acidic and dehydrated ASL, causing reduced antimicrobial properties and mucociliary clearance. [ABSTRACT FROM AUTHOR]

• Urinary acrolein is increased in people with CF who are exposed to tobacco smoke. • Urinary acrolein is associated with at least 12 mmol/L less improvement in sweat chloride after 6 months of ivacaftor treatment, a deficit equivalent to the treatment effect of tezacaftor/ivacaftor in F508del homozygous patients or those with residual CFTR function. • People with CF with low urinary acrolein have 2.5 times higher odds of a robust response to ivacaftor (sweat chloride <40 mmol/L) than counterparts with high urinary acrolein. • Limiting the sources of acrolein exposure, including tobacco smoke, may optimize the efficacy of CFTR modulators. Acrolein, an aldehyde in smoke from tobacco products, inhibits CFTR function in vitro. Ivacaftor is an FDA-approved potentiator that improves mutant CFTR function. This human clinical study investigated the relationship between two urinary markers of tobacco smoke exposure – the acrolein metabolite 3-HPMA and the nicotine metabolite NNAL – and sweat chloride response to ivacaftor in the G551D Observational Trial (GOAL). 3-HPMA (low: <50th centile; moderate: 50-75th centile; high: >75th centile) and NNAL (detectable/undetectable) in GOAL samples was quantified with LC-MS/MS. Self-report of tobacco smoke exposure (Y/N) served as a subjective measure. Change in sweat chloride from pre- to 6 months post-ivacaftor treatment (ΔSC) was the primary CFTR-dependent readout. The sample included 151 individuals, mean age 20.7 (SD 11.4) years, range 6-59 years. Smoke exposure prevalence was 15 % per self-reports but 27 % based on detectable NNAL. 3-HPMA was increased in those reporting tobacco smoke exposure (607 vs 354 ng/ml, p = 0.008), with a higher proportion of smoke-exposed in the high- vs low-acrolein group (31 % vs 9 %, p=0.040). Compared to low-acrolein counterparts, high-acrolein participants experienced less decrease in sweat chloride (-35.2 vs -48.2 mmol/L; p = 0.020) and had higher sweat chloride values (50.6 vs 37.6 mmol/L; p = 0.020) 6 months post-ivacaftor. The odds of ivacaftor-mediated potentiation to near normative CFTR function (defined as SC 6mo <40 mmol/L) was more than twice as high in the low-acrolein cohort (OR: 2.51, p = 0.026). Increased urinary 3-HPMA, an acrolein metabolite of tobacco smoke, is associated with a diminished sweat chloride response to ivacaftor potentiation of CFTR function. [ABSTRACT FROM AUTHOR]

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• Interrupted time series analysis was performed on large representative CF populations from US and UK registries to interpret the impact of ivacaftor licensing on PERT prescription. • In the US CF registry, there was an annual decline in the prevalence of recorded PERT use following ivacaftor licensing compared to prior, relative to propensity matched controls, although this was not observed in the UK CF registry. • Ivacaftor may reduce the severity of exocrine pancreatic insufficiency in a registry population, however effect sizes were small and changes in PERT dosage could not be modelled. Relieving gastrointestinal symptoms is a research priority in cystic fibrosis. Emerging evidence highlights effects of cystic fibrosis transmembrane conductance regulator (CFTR) modulators on gastrointestinal function, including pancreatic sufficiency. This study explores ivacaftor licensing and treatment on recorded pancreatic enzyme replacement therapy (PERT) prescription in the US and UK CF registries. Retrospective longitudinal registry study of recorded pancreatic PERT use between 2008 and 2017. Interrupted time series analysis in propensity-matched cohorts estimated annual change and step change according to ivacaftor eligibility before and after licensing year, 2012. Generalised estimating equations assessed adjusted risk of PERT use in individuals treated with ivacaftor after 2012 compared to untreated individuals. In the US CF registry, the difference in annual change in prevalence of PERT use post-2012 between eligible cases and ineligible controls was -5.0 per 1000 people/year (95 %CI -7.6; -2.3, p = 0.001). The step change and annual change in prevalence of PERT use in eligible cases was not significantly different to controls in the UK CF registry. Relative to the relationship in 2013, ivacaftor treatment in the US CF registry was associated with a lower adjusted risk ratio of PERT use compared to untreated individuals by 2016 (0.97, 95 %CI 0.96; 0.99), which was not observed in the UK CF registry. Licensing of ivacaftor was followed by a lower prevalence of PERT use in the eligible US population compared to pre-licensing period, as well as lower risk of PERT use in those who received treatment. Inconsistencies in US and UK CF registries were observed. [ABSTRACT FROM AUTHOR]

The introduction of CFTR modulator drugs like elexacaftor-tezacaftor-ivacaftor (ETI) has transformed the management of cystic fibrosis (CF), significantly improving symptoms, lung function, and quality of life, while reducing reliance on intravenous antibiotics. However, respiratory exacerbations in the CFTR modulators era remain poorly understood from both pathophysiological and clinical perspectives.We present the case of a 20-year-old Caucasian woman with CF (F508del/L1077P) who, after three years of ETI treatment, experienced a severe episode of hemoptysis, despite being almost asymptomatic in the weeks leading up to admission, requiring bronchial artery embolization. Following ETI treatment, auscultatory findings and FEV1 changes may be less significant, making the detection of respiratory exacerbation more challenging. This highlights the need for heightened vigilance in managing such cases and underscores the challenge of diagnosing and managing exacerbations in the era of modulators. Long term real-world studies are essential to comprehend the evolving course of the disease during ETI treatment.