F508del Mutation Research Articles

Elexacaftor-Tezacaftor-Ivacaftor Treatment Reduces Abdominal Symptoms in Cystic Fibrosis-Early results Obtained With the CF-Specific CFAbd-Score.

Background: The novel and highly effective CFTR modulator combination of elexacaftor-tezacaftor-ivacaftor (ETI) has been shown to improve lung function and body weight in people with Cystic Fibrosis (pwCF) carrying a F508del mutation. However, the impact of these modulators on gastrointestinal (GI) symptoms is relatively unknown. Therefore, the CFAbd-Score was developed and validated following FDA recommendations for development of a PROM including focus groups, multidisciplinary CF specialists, people with CF and their families. The aim of this study was to assess effects of ETI on GI symptoms using the CFAbd-Score. Methods: Gastrointestinal symptoms were prospectively assessed in pwCF using the CFAbd-Score before and up to 26 weeks during therapy. The CFAbd-Score was also administered to a healthy control (HC) group. The one-sided questionnaire includes 28 items grouped in five domains. Data analysis included calculation of scores with a weighting tool, developed according to FDA recommendations. Results: A total of 107 pwCF attended in four CF centres in Germany and four centres in the UK completed the CFAbd-Score on at least two occasions. Results were compared to those obtained from the questionnaire of 45 HCs. Despite differences in demographics, age and proportion of pancreatic insufficiency between German and UK patients, analyses based on linear mixed-effects models at week 24 of ETI therapy revealed that estimated marginal means (EMMs) of total CFAbd-Scores significantly reduced (mean ± SE: 14.9 ± 1.2→10.6 ± 1.4; p < 0.01). Also EMMs of all five domains significantly declined (“pain” 16.3 ± 1.6→10.2 ± 2.3, “GERD” 15.8 ± 1.8→8.2 ± 1.9, “disorders of bowel movement” 20.9 ± 1.5→16.0 ± 1.7, “disorders of appetite” 7.9 ± 1.1→2.6 ± 1.1 and “quality of life impairment” 10.1 ± 1.92→3.9 ± 1.9). However, during 24 weeks, CF participants’ symptoms mostly still did not reach the reference levels of HCs. Discussion: Using the CFAbd-Score, the first PROM specifically developed for assessment of CF-related abdominal symptoms, we demonstrate comprehensive improvements in GI symptoms after initiation of the highly effective modulator therapy ETI.

Losartan ameliorates TGF-β1-induced CFTR dysfunction and improves correction by cystic fibrosis modulator therapies.

Highly effective modulator therapies dramatically improve the prognosis for those with cystic fibrosis (CF). The triple combination of elexacaftor, tezacaftor, and ivacaftor (ETI) benefits many, but not all, of those with the most common F508del mutation in the CF transmembrane conductance regulator (CFTR). Here, we showed that poor sweat chloride concentration responses and lung function improvements upon initiation of ETI were associated with elevated levels of active TGF-β1 in the upper airway. Furthermore, TGF-β1 impaired the function of ETI-corrected F508del-CFTR, thereby increasing airway surface liquid (ASL) absorption rates and inducing mucus hyperconcentration in primary CF bronchial epithelial cells in vitro. TGF-β1 not only decreased CFTR mRNA, but was also associated with increases in the mRNA expression of TNFA and COX2 and TNF-α protein. Losartan improved TGF-β1–mediated inhibition of ETI-corrected F508del-CFTR function and reduced TNFA and COX2 mRNA and TNF-α protein expression. This likely occurred by improving correction of mutant CFTR rather than increasing its mRNA (without an effect on potentiation), thereby reversing the negative effects of TGF-β1 and improving ASL hydration in the CF airway epithelium in vitro. Importantly, these effects were independent of type 1 angiotensin II receptor inhibition.

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.

Human Amniotic Mesenchymal Stem Cells and Fibroblasts Accelerate Wound Repair of Cystic Fibrosis Epithelium.

Cystic fibrosis (CF) airways are affected by a deranged repair of the damaged epithelium resulting in altered regeneration and differentiation. Previously, we showed that human amniotic mesenchymal stem cells (hAMSCs) corrected base defects of CF airway epithelial cells via connexin (CX)43-intercellular gap junction formation. In this scenario, it is unknown whether hAMSCs, or fibroblasts sharing some common characteristics with MSCs, can operate a faster repair of a damaged airway epithelium. A tip-based scratch assay was employed to study wound repair in monolayers of CFBE14o- cells (CFBE, homozygous for the F508del mutation). hAMSCs were either co-cultured with CFBE cells before the wound or added to the wounded monolayers. NIH-3T3 fibroblasts (CX43+) were added to wounded cells. HeLa cells (CX43-) were used as controls. γ-irradiation was optimized to block CFBE cell proliferation. A specific siRNA was employed to downregulate CX43 expression in CFBE cells. CFBE cells showed a delayed repair as compared with wt-CFTR cells (16HBE41o-). hAMSCs enhanced the wound repair rate of wounded CFBE cell monolayers, especially when added post wounding. hAMSCs and NIH-3T3 fibroblasts, but not HeLa cells, increased wound closure of irradiated CFBE monolayers. CX43 downregulation accelerated CFBE wound repair rate without affecting cell proliferation. We conclude that hAMSCs and fibroblasts enhance the repair of a wounded CF airway epithelium, likely through a CX43-mediated mechanism mainly involving cell migration.

Who are the 10%? - Non eligibility of cystic fibrosis (CF) patients for highly effective modulator therapies

BackgroundThe availability of mutation-specific cystic fibrosis modulator therapies has the potential to improve the lives of children and adults with cystic fibrosis. The frequency of mutations causing defects in the cystic fibrosis transmembrane conductance regulator (CFTR) function varies between sub-groups in multi-ethnic populations. The profile of patients eligible for CFTR modulator ivacaftor/tezacaftor/elexacaftor (Kaftrio™) therapy based on ethnicity has not been reported in the United Kingdom CF population. MethodsWe conducted a descriptive cross-sectional analysis of patients in the UK CF Registry who had annual review data submissions in 2019. Data analysed included demographic characteristics, spirometry, chronic Pseudomonas status, nutrition, and CF related diabetes status. The genotype data was stratified by whether there was at least one copy of F508del or no copy of F508del as current eligibility for ivacaftor/tezacaftor/elexacaftor, or projected future eligibility, is defined as having at least one copy of F508del mutation. ResultsData from 9887 patients were reviewed, 46.7% female, mean age 22.5 years. 8.6% (n = 852) patients had no copy of F508del making them ineligible for ivacaftor/tezacaftor/elexacaftor. Overall, 93.4% of patients were of white ethnicity, with a similar proportion of those with at least one F508del being white (95.6%). This was reduced to 70.0% of those with no F508del. The proportion of people of Asian ethnicity was much higher in the no F508del group (19.2% vs 1.2%). Compared with one F508del patients, the no F508del group were older (25.2 years vs 22.2 years, p < 0.001), had higher prevalence of pancreatic sufficiency (39.0% vs 14.9% p < 0.001), lower prevalence of chronic Pseudomonas infection (21.1% vs. 26.6%, p < 0.001), and higher best FEV1 from the previous year (proportion with greater than 70% FEV1 predicted, 66.1% vs 63.0%, p = 0.005). ConclusionPatients from black, Asian and minority ethnic backgrounds are significantly less likely to be eligible for ivacaftor/tezacaftor/elexacaftor based on the current prescribing policy in the UK. At present this is the most highly effective CF modulator therapy available to treat people with CF. The CF community should urgently address the unmet need for effective targeted therapies for patients without F508del.

Elexacaftor-Tezacaftor-Ivacaftor as a Final Frontier in the Treatment of Cystic Fibrosis: Definition of the Clinical and Microbiological Implications in a Case-Control Study.

The use of modulator drugs that target the Cystic Fibrosis transmembrane conductance regulator (CFTR) is the final frontier in the treatment of Cystic Fibrosis (CF), a genetic multiorgan disease. F508del is the most common mutation causing defective formation and function of CFTR. Elexacaftor-tezacaftor-ivacaftor is the first triple combination of CFTR modulators. Herein, we report on a one-year case-control study that involved 26 patients with at least one F508del mutation. Patients were assigned to two similar groups, and patients with the worse clinical condition received treatment with the triple combination therapy. The study aimed to define the clinical and especially microbiological implications of treatment administration. The treatment provided significant clinical benefits in terms of respiratory, pancreatic, and sweat function. After one year of therapy, airway infection rates decreased and pulmonary exacerbations were dramatically reduced. Finally, treated patients reported a surprising improvement in their quality of life. The use of triple combination therapy has become essential in most CF people carrying the F508del mutation. Although the clinical and instrumental benefits of treatment are thoroughly known, further investigations are needed to properly define its microbiological respiratory implications and establish the real advantage of life-long treatment with elexacaftor-tezacaftor-ivacaftor.

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

BackgroundOver 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.ResultsCFTR 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.ConclusionsRegulators 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.

Select Amino Acids Increase Anion Secretion in Human Bronchial Epithelial Cells (HBEC) with F508del and Nonsense Mutations: Alternative Approach to Restoring Airway Anion Secretion in Cystic Fibrosis

ObjectiveChloride and bicarbonate transport across the apical membrane via CFTR is critical for homeostasis of airway surface liquid and mucociliary clearance. Cystic fibrosis (CF) is caused by mutations in the CFTR gene resulting in mucus buildup, bacterial colonization, inflammation and respiratory insufficiency. F508del and nonsense mutations are the most common mutations characterized by defective protein processing and trafficking (F508del) or early termination of CFTR synthesis (G542X, R1162X). A combination of CFTR modulators (VX445/661/770; VX) has largely improved CFTR function in patients with F508del but is ineffective in nonsense mutations. We have shown that select amino acids (SAA) can modulate trafficking and activity of CFTR and alternative anion‐secretory pathways, and thus could improve clinical outcomes in CF patients.HypothesisSAA can stimulate anion secretion in primary HBEC with F508del/F508del, F508del/R1162X and G542X/G542X mutation.MethodsTransepithelial short‐circuit current (Isc) was measured in differentiated HBEC treated with DMSO or VX for 24h and bathed in vehicle or SAA in Ussing chambers. After blocking ENaC with benzamil, benzamil‐insensitive (anion) Isc was either continuously recorded for 90min, or sequentially blocked with CFTRinh172, CaCCinhA01 and bumetanide in 15min intervals. Isotope (36Cl) flux studies and whole‐cell patch clamp technique were used to confirm chloride movements, and CFTR and alternative anion‐secretory channel expression was analyzed by immunofluorescence.ResultsAnion Isc increased in all mutations and was more sustained when exposed to SAA compared to vehicle (F508del: 15.4±0.5 vs 1.4±0.2; R1162X: 19.4±0.3 vs 2.3±0.3; G542X: 17.2±0.5 vs 1.6±0.2 µA.cm‐2; P&lt;0.001). SAA recovered 48.7, 57.3 and 40.9% of normal Isc (21.9±0.5 µA.cm‐2). Treatment with VX increased anion Isc in F508del and R1162X (11.4±0.7 and 5.7±0.4 µA.cm‐2; P&lt;0.001) but not in G542X (1.7±0.2 µA.cm‐2). In F508del, the CFTR response increased from 20.7% (non‐treated cells) to 32.9 and 85.5% of the anion Isc when treated with SAA or VX, and in R542X from 3.7% to 46.3 and 16.0%, respectively. Both, SAA and VX did not affect CaCC, but SAA increased the bumetanide‐sensitive Isc from 31.0 to 50.5% in F508del, and from 33.3 to 56.3% in R1162X, while VX reduced the bumetanide response to 5.4 and 4.5%. Isotope flux studies showed that SAA (‐0.21±0.08 μEq.h‐1.cm‐2) and VX (‐0.19±0.02 μEq.h‐1.cm‐2) increased net Cl‐ secretion in F508del when compared to vehicle (‐0.03±0.01 μEq.h‐1.cm‐2; P&lt;0.05). SAA, but not VX increased Cl‐ secretion in G542X (‐0.21 0.07 vs ‐0.08±0.02 μEq.h‐1.cm‐2). In patch clamp recordings, SAA and VX resulted in a significant reduction in CFTRinh172 whole cell current in F508del. Immunofluorescence imaging demonstrated increased CFTR and alternative anion‐secretory channel expression along the apical membrane in SAA cells while VX showed increased expression of only CFTR.ConclusionsThese studies demonstrate that SAA stimulates anion current and increases Cl‐ secretion via CFTR and alternative secretory pathways in different mutations, and could be beneficial in nonsense mutations but needs further investigation.

Systemic bis-phosphinic acid derivative restores chloride transport in Cystic Fibrosis mice

Mutations in the Cystic Fibrosis Transmembrane Conductance Regulator gene (CFTR) are responsible for Cystic Fibrosis (CF). The most common CF-causing mutation is the deletion of the 508th amino-acid of CFTR (F508del), leading to dysregulation of the epithelial fluid transport in the airway’s epithelium and the production of a thickened mucus favoring chronic bacterial colonization, sustained inflammation and ultimately respiratory failure. c407 is a bis-phosphinic acid derivative which corrects CFTR dysfunction in epithelial cells carrying the F508del mutation. This study aimed to investigate c407 in vivo activity in the F508del Cftrtm1Eur murine model of CF. Using nasal potential difference measurement, we showed that in vivo administration of c407 by topical, short-term intraperitoneal and long-term subcutaneous route significantly increased the CFTR dependent chloride (Cl−) conductance in F508del Cftrtm1Eur mice. This functional improvement was correlated with a relocalization of F508del-cftr to the apical membrane in nasal epithelial cells. Importantly, c407 long-term administration was well tolerated and in vitro ADME toxicologic studies did not evidence any obvious issue. Our data provide the first in vivo preclinical evidence of c407 efficacy and absence of toxicity after systemic administration for the treatment of Cystic Fibrosis.

Magnetic resonance imaging detects improvements of pulmonary and paranasal sinus abnormalities in response to elexacaftor/tezacaftor/ivacaftor therapy in adults with cystic fibrosis

BackgroundTherapy with Elexacaftor/Tezacaftor/Ivacaftor (ETI) was recently approved for adult cystic fibrosis (CF) patients with at least one F508del mutation. However, its effects on structural and functional lung abnormalities and chronic rhinosinusitis have not been studied by imaging. Methods19 adults with CF (mean age 31±9y, range 19–55y) underwent standardized chest magnetic resonance imaging (MRI), and nine also same-session sinonasal MRI, before (MRI1) and after (MRI2) at least one month (mean duration 5 ± 3mon) on ETI. 24 control CF patients (30±7y, range 20–44y) without ETI underwent longitudinal chest MRI, and eleven also sinonasal MRI, twice (mean interval 40±15mon). MRI was assessed using the validated chest MRI score and chronic rhinosinusitis (CRS)-MRI score. Forced expiratory volume in 1 s percent predicted (FEV1%) was measured in all patients. ResultsIn controls, the chest MRI global score and CRS-MRI sum score were stable from MRI1 to MRI2. In patients under ETI, the chest MRI global score improved (-11.4 ± 4.6, P<0.001), mainly due to reduction of bronchiectasis/wall thickening and mucus plugging subscores (-3.3 ± 2.2 and -5.2 ± 1.5, P<0.001, respectively). The improvement in chest MRI score correlated well with improved FEV1% (r=-0.703, P<0.001). The CRS-MRI sum score also improved in patients under ETI (-6.9 ± 3.0, P<0.001), mainly due to a reduction of mucopyoceles in the maxillary and ethmoid sinus (-50% and -39%, P<0.05, respectively). ConclusionsMRI detects improvements of chest MRI and CRS-MRI scores in adult CF patients who first received ETI, demonstrating reversibility of structural lung and paranasal sinus abnormalities in patients with established disease.

Unmasking hereditary hemochromatosis with CFTR modulator therapy

Cystic Fibrosis (CF) is a genetic condition affecting the ability to excrete chloride, resulting in multi-system organ damage. Liver disease is one co-morbidity that affects 20-40% of people with CF. This case describes a 16-year-old male with CF (F508Del and Q493X mutations) who was started one lexacaftor/tezacaftor/ifacaftortriple CF Transmembrane Regulator (CFTR) modulator therapy. Prior to starting treatment, it was noted that he had transaminitis (AST 69, ALT 120, Total bilirubin 0.4). His liver enzymes continued to increase with therapy and at week 8 of treatment he complained of abdominal pain, body aches, and fatigue warranting further evaluation. At that time, AST and ALT were elevated at 5- and 13-times the Upper Limits of Normal (ULN) and creatinine kinase was elevated at 12-times ULN. A dose reduction led to a decrease in AST and ALT to 2 and 4-times ULN, but total and direct bilirubin increased to 2.2 mg/dl and 0.5 mg/dl, warranting a liver ultrasound and biopsy. Pathology showed fatty liver and hepatocyte iron deposition, but no indications of cirrhosis. Iron studies and genetic testing confirmed a diagnosis of HH (Homozygous HIS63ASP gene mutation). After stopping triple CFTR modulator therapy, AST and ALT continued to rise, prompting further evaluation by hepatology and hematology. Upon discontinuation of drug therapy, his lung function dropped significantly back to baseline values and respiratory symptoms returned. Discussion: Hereditary hemochromatosis gene mutations have been shown to have a gene modulating impact on CFTR gene mutations that can affect CF disease phenotype, which negatively affects pulmonary function and gastrointestinal disease. In this case, the introduction of a new medication instigated further work-up leading to the discovery of a potential alternative cause of hepatic dysfunction while attempting to optimize medications to sustain improvements in pulmonary function. Although elevated hepatic transaminases can be expected from CF and CFTR modulator therapy, further investigation may be indicated in patients with persistent elevations despite medication adjustments. This workup may lead to important considerations in balancing liver function with lung function. Keywords: cystic fibrosis; elexacaftor; tezacaftor; ivacaftor; liver transaminases; hereditary hemochromatosis.

Lipid-driven CFTR clustering is impaired in cystic fibrosis and restored by corrector drugs.

ABSTRACTMembrane proteins often cluster in nanoscale membrane domains (lipid rafts) that coalesce into ceramide-rich platforms during cell stress, however the clustering mechanisms remain uncertain. The cystic fibrosis transmembrane conductance regulator (CFTR), which is mutated in cystic fibrosis (CF), forms clusters that are cholesterol dependent and become incorporated into long-lived platforms during hormonal stimulation. We report here that clustering does not involve known tethering interactions of CFTR with PDZ domain proteins, filamin A or the actin cytoskeleton. It also does not require CFTR palmitoylation but is critically dependent on membrane lipid order and is induced by detergents that increase the phase separation of membrane lipids. Clustering and integration of CFTR into ceramide-rich platforms are abolished by the disease mutations F508del and S13F and rescued by the CFTR modulators elexacaftor plus tezacaftor. These results indicate CF therapeutics that correct mutant protein folding restore both trafficking and normal lipid interactions in the plasma membrane.This article has an associated First Person interview with the first author of the paper.

Elexacaftor/Tezacaftor/Ivacaftor in Patients with Cystic Fibrosis Homozygous for the F508del Mutation and Advanced Lung Disease: A 48-Week Observational Study.

Background: Elexacaftor/tezacaftor/ivacaftor (ETI) is the newest cystic fibrosis transmembrane conductance regulator (CFTR) modulator drug approved for the treatment of patients with cystic fibrosis (pwCF) aged ≥6 years with at least one copy of the F508del mutation (F) in the CFTR gene or another mutation that is responsive to treatment with ETI. This study determined the effectiveness and safety of ETI in a cohort of severely affected pwCF with an F/F genotype. Methods: Retrospective observational study in F/F pwCF treated for 48 weeks, enrolled in an ETI managed access program available to subjects with advanced lung disease (ppFEV1 < 40). Twenty-six patients from three centres were included. The main outcomes included lung function, sweat chloride concentration (SCC), nutrition, frequency of pulmonary exacerbations (PEx), CFQ-R, and safety. Results: ppFEV1 improved by 12.06 (95%CI 8.54, 15.57) from baseline after 4 weeks of treatment with ETI, 15.32 (11.3, 19.34) after 24 weeks, and 14.48 (10.64, 18.32) after 48 weeks. The increase in FEV1 was accompanied by a decrease in SCC, improvement of BMI, and noticeable reduction in PEx. An overall good safety profile was observed. Conclusions: In F/F pwCF with advanced lung disease with an F/F genotype, ETI was safe and associated with clinical improvement.

Italian Cystic Fibrosis Registry (ICFR). Report 2019-2020

Italian Cystic Fibrosis Registry (ICFR). Report 2019-2020

Prediction of Real-World Long-Term Outcomes of People with CF Homozygous for the F508del Mutation Treated with CFTR Modulators

The clinical response to cystic fibrosis transmembrane conductance regulator (CFTR) modulators is variable within people with cystic fibrosis (pwCF) homozygous for the F508del mutation. The prediction of clinical effect in individual patients would be useful to target therapy to those who would benefit from it. A multicenter observational cohort study was conducted including 97 pwCF (F508del/F508del), who started lumacaftor/ivacaftor (LUM/IVA) treatment before June 2018. In order to assess the associations of individual in vivo and in vitro biomarkers with clinical outcomes, we collected clinical data regarding sex, age, and sweat chloride concentration (SwCl) at baseline and after six months of LUM/IVA; the percent predicted forced expiratory volume in 1 s (ppFEV1) and the number of pulmonary exacerbations (PEx) during the three years before up to three years after modulator initiation; and the forskolin-induced swelling (FIS) responses to LUM/IVA, quantified in intestinal organoids. On a group level, the results showed an acute change in ppFEV1 after LUM/IVA initiation (2.34%, 95% CI 0.85–3.82, p = 0.003), but no significant change in annual ppFEV1 decline in the three years after LUM/IVA compared to the three years before (change: 0.11% per year, 95%CI: −1.94–2.19, p = 0.913). Neither of these two outcomes was associated with any of the candidate predictors on an individual level. The median number of pulmonary exacerbations (PEx) per patient year did not significantly change in the three years after LUM/IVA compared to the years before (median: 0.33/patient year, IQR: 0–0.67 before vs. median: 0/patient year, IQR: 0–0.67 after p = 0. 268). The PEx rate after modulator initiation was associated with the PEx rate before (IRR: 2.26, 95%CI: 1.67–3.08, p < 0.001), with sex (males vs. females IRR: 0.36, 95%CI: 0.21–0.63, p = 0.001) and with sweat chloride concentration (SwCl) at baseline (IRR: 0.96, 95%CI: 0.94–0.98, p = 0.001). The change in SwCl was also significant (−22.9 mmol/L (95%CI: −27.1–−18.8, p < 0.001) and was associated with SwCl at baseline (−0.64, 95%CI: −0.90–−0.37, p < 0.001) and with sex (males vs. females 8.32, 95%CI: 1.82–14.82, p = 0.013). In conclusion, ppFEV1 decline after CFTR modulator initiation remains difficult to predict in individual patients in a real-world setting, with limited effectiveness for double CFTR modulator therapies. The PEx rate prior to CFTR modulator treatment initiation, sex and SwCl at baseline could be potential predictors of long-term PEx rate and of changes in SwCl after modulator initiation.

ЛАПАРОСКОПИЧЕСКИЙ МЕЖКИШЕЧНЫЙ АНАСТОМОЗ SANTULLI У МЛАДЕНЦА С МУКОВИСЦИДОЗОМ

The aim of the study was to evaluate the technical feasibility of performing a Santulli-type side-toend inter-intestinal anastomosis in infants with cystic fibrosis (CF) using laparoscopy. A clinical case of a 3-month-old child with CF who was operated on in the neonatal period for meconium ileus is presented. The baby's gestational age was 32 weeks. The primary operation consisted of the formation of a terminal enterostomy. In the postoperative period, a malabsorption syndrome was noted, accompanied by a lack of growth. As a temporary measure to restore nutritional status, a Santulli-style side-to-end laparoscopic intestinal anastomosis was performed. The observed child was found to have the F508del mutation in both alleles of the CFTR gene. The patient's weight at the time of the Santulli anastomosis construction was 2900 g, the age – 3 months. During the operation, there were no difficulties associated with the mobilization of the separated segments of the ileum. The duration of the surgical intervention was 70 min. Enteral nutrition was started on the 3rd day after the operation. The recovery period for intestinal transit through the rectum was 15 days. The postoperative period was uneventful. The duration of hospitalization was 18 days. No electrolyte imbalance or excessive fluid loss or underweight associated with enterostomy was observed. Over the next 6 months, the normalization of age-related weight and height parameters was achieved, after which the continuity of the digestive tract was restored by closing the terminal enterostomy. Currently, the patient has minimal respiratory symptoms and is receiving adequate CF therapy with pancreatic enzyme replacement therapy included with each meal. The initial experience of performing laparoscopic Santulli inter-intestinal anastomosis in an infant with CF presented in the study showed the possibility and reproducibility of this technique, expanding the boundaries of laparoscopy in pediatric practice. The decision to close the enterostomy in these patients should be deferred until a full diet is introduced and should be made in conjunction with a pediatrician specializing in the treatment of CF.

Elexacaftor-Tezacaftor-Ivacaftor and Ivacaftor (Trikafta)

&#x0D; CADTH reimbursement reviews are comprehensive assessments of the clinical effectiveness and cost-effectiveness, as well as patient and clinician perspectives, of a drug or drug class.&#x0D; The assessments inform non-binding recommendations that help guide the reimbursement decisions of Canada's federal, provincial, and territorial governments, with the exception of Quebec.&#x0D; This review assesses ELX-TEZ-IVA (Trikafta) and ELX 100 mg, TEZ 50 mg, IVA 75 mg (combination tablet), and 150 mg IVA (tablet); oral.&#x0D; Indication: Treatment of cystic fibrosis in patients aged ≥ 12 years who have at least 1 F508del mutation in the cystic fibrosis transmembrane conductance regulator gene.&#x0D;

Factors for severe outcomes following SARS-CoV-2 infection in people with cystic fibrosis in Europe.

BackgroundSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in people with cystic fibrosis (pwCF) can lead to severe outcomes.MethodsIn this observational study, the European Cystic Fibrosis Society Patient Registry collected data on pwCF and SARS-CoV-2 infection to estimate incidence, describe clinical presentation and investigate factors associated with severe outcomes using multivariable analysis.ResultsUp to December 31, 2020, 26 countries reported information on 828 pwCF and SARS-CoV-2 infection. Incidence was 17.2 per 1000 pwCF (95% CI: 16.0–18.4). Median age was 24 years, 48.4% were male and 9.4% had lung transplants. SARS-CoV-2 incidence was higher in lung-transplanted (28.6; 95% CI: 22.7–35.5) versus non-lung-transplanted pwCF (16.6; 95% CI: 15.4–17.8) (p≤0.001).SARS-CoV-2 infection caused symptomatic illness in 75.7%. Factors associated with symptomatic SARS-CoV-2 infection were age >40 years, at least one F508del mutation and pancreatic insufficiency.Overall, 23.7% of pwCF were admitted to hospital, 2.5% of those to intensive care, and regretfully 11 (1.4%) died. Hospitalisation, oxygen therapy, intensive care, respiratory support and death were 2- to 6-fold more frequent in lung-transplanted versus non-lung-transplanted pwCF.Factors associated with hospitalisation and oxygen therapy were lung transplantation, cystic fibrosis-related diabetes (CFRD), moderate or severe lung disease and azithromycin use (often considered a surrogate marker for Pseudomonas aeruginosa infection and poorer lung function).ConclusionSARS-CoV-2 infection yielded high morbidity and hospitalisation in pwCF. PwCF with forced expiratory volume in 1 s <70% predicted, CFRD and those with lung transplants are at particular risk of more severe outcomes.

Ultrasound findings of pubertal development in girls with cystic fibrosis and their association with clinical outcomes and Tanner staging.

Patients with cystic fibrosis (CF) have a high incidence of pubertal and growth delay. In girls with CF, pubertal delay has an important psychological impact. Still, only a few studies have explored the occurrence of pubertal delay in girls with CF. The aims of this study were to compare the pubertal development of girls with CF compared with healthy controls regarding Tanner staging and pelvic ultrasound and, in girls with CF, correlate the findings with those of spirometry, body mass index, Shwachman-Kulczycki score (SKS), and genotyping. This was a cross-sectional, case-control study including 35 girls with CF aged 6-17 years and following up at the Pediatric Pulmonology Outpatient Clinic of a tertiary hospital. These patients were compared with 59 healthy controls who had undergone pelvic ultrasound as part of another study conducted by the same group. Girls with CF were consecutively enrolled in the study during their annual routine check-up visit. Data collected in the CF group included spirometry and anthropometric results, SKS values, bone age, occurrence of current cystic fibrosis-related diabetes (CFRD) and Pseudomonas aeruginosa colonization, history of meconium ileus, genotype, ultrasound parameters, and Tanner stage. Pelvic ultrasound findings and Tanner stage reflected less pubertal development in girls with CF compared with healthy controls. Pubertal stage in patients with CF who presented CFRD (3.17 ± 1.16), had chronic colonization by Pseudomonas aeruginosa (3.10 ± 1.10), or were homozygous for the F508del mutation (1.91 ± 1.30) was more delayed than in controls (3.41 ± 1.41). Tanner stage correlated with age at menarche, bone age, and anthropometric and ultrasound data. Girls with CF presented a delay in pubertal development evaluated by Tanner stage and ultrasound parameters, which was more evident in the presence of comorbidities.

NBD2 Is Required for the Rescue of Mutant F508del CFTR by a Thiazole-Based Molecule: A Class II Corrector for the Multi-Drug Therapy of Cystic Fibrosis.

Cystic fibrosis (CF) is caused by loss-of-function mutations in the CF transmembrane conductance regulator (CFTR) protein, an anion channel that regulates epithelial surface fluid secretion. The deletion of phenylalanine at position 508 (F508del) is the most common CFTR mutation. F508del CFTR is characterized by folding and trafficking defects, resulting in decreased functional expression of the protein on the plasma membrane. Several classes of small molecules, named correctors, have been developed to rescue defective F508del CFTR. Although individual correctors failed to improve the clinical status of CF patients carrying the F508del mutation, better results were obtained using correctors combinations. These results were obtained according to the premise that the administration of correctors having different sites of action should enhance F508del CFTR rescue. We investigated the putative site of action of an aminoarylthiazole 4-(3-chlorophenyl)-N-(3-(methylthio)phenyl)thiazol-2-amine, named FCG, with proven CFTR corrector activity, and its synergistic effect with the corrector VX809. We found that neither the total expression nor the maturation of WT CFTR transiently expressed in human embryonic kidney 293 cells was influenced by FCG, administrated alone or in combination with VX809. On the contrary, FCG was able to enhance F508del CFTR total expression, and its combination with VX809 provided a further effect, being able to increase not only the total expression but also the maturation of the mutant protein. Analyses on different CFTR domains and groups of domains, heterologously expressed in HEK293 cells, show that NBD2 is necessary for FCG corrector activity. Molecular modelling analyses suggest that FCG interacts with a putative region located into the NBD2, ascribing this molecule to class II correctors. Our study indicates that the continuous development and testing of combinations of correctors targeting different structural and functional defects of mutant CFTR is the best strategy to ensure a valuable therapeutic perspective to a larger cohort of CF patients.