[Adverse effects of the tezacaftor/ivacaftor/elexacaftor combination that may lead to discontinuation: About a series of 10 cases]. / Effets indésirables de l'association tezacaftor/ivacaftor/elexacaftor pouvant mener à un arrêt de traitement : à propos d'une série de 10 cas.

INTRODUCTION: Cystic fibrosis transmembrane regulator (CFTR) channel modulators (ivacaftor, lumacaftor, tezacaftor and elexacaftor) represent a major advance in the management of cystic fibrosis. However, few data are available on the real-life safety profile of these medications, in particular on adverse events that may lead to their discontinuation. The aim of this study is to describe the characteristics and evolution of adverse reactions to the tezacaftor/ivacaftor/elexacaftor combination that led to discontinuation and were reported to the Centre régional de pharmacovigilance (CRPV) in Rennes (France). MATERIALS AND METHODS: A retrospective study was conducted from December 2021 to May 2023, focusing on cases of discontinuation of the tezacaftor/ivacaftor/elexacaftor combination due to the occurrence of one or more adverse effects, and reported to the CRPV of Rennes, France. RESULTS: Ten cases of drug discontinuation were reported to the Rennes CRPV (6 women/4 men). Adverse effects mainly involved neuropsychiatric disorders (n=6), followed by liver disorders (n=2), ear, nose and throat disorders (n=1), and digestive disorders (n=1). The average duration of treatment at discontinuation was 339.8 [39-668] days. The drug was reintroduced in 7 patients on average 48.7 [7-123] days after discontinuation, with a dosage adjustments (n=4) consisting of changes in dosing times or a reduction in daily doses, with varying success in alleviating adverse symptoms depending on the case. CONCLUSION: This small case series suggests that neuropsychiatric adverse effects may occur more frequently than initially described after initiation of tezacaftor/ivacaftor/elexacaftor, and should be carefully screened and monitored. Dosage or administration schedule modifications may be considered for patients experiencing these adverse effects. Further pharmacovigilance studies are needed to better understand the adverse effect profiles of "caftors", their possible risk factors, and the impact of adjusting dosing modalities.

Cystic fibrosis-related chronic rhinosinusitis: the key role of a comprehensive evaluation in the era of highly effective modulator therapy.

BACKGROUND: Chronic rhinosinusitis (CRS) is prevalent in cystic fibrosis (CF), significantly affecting quality of life. The introduction of CFTR modulators, including elexacaftor-tezacaftor-ivacaftor (ETI), offers promise for improving sinonasal outcomes. METHODS: We conducted a retrospective cohort multicenter study analyzing electronic medical records of 45 adult CF patients with CRS, predominantly heterozygous for the ΔF508 mutation, treated with ETI between January 2018 and December 2023. Assessments included Sinonasal Outcome Test 22 (SNOT-22), Nasal Polyp Score (NPS), modified Lund-Kennedy Score (mLKS), Lund-Mackay Score (LMS), and olfactory function using smell loss visual analog scale (VAS) and Sniffin' Sticks identification test (SSIT). RESULTS: After 12 months of ETI therapy, significant improvements were observed in pulmonary function parameters (FEV1, FVC), CRS severity scores (SNOT-22, NPS, mLKS), radiological findings (LMS), and olfactory function. Subgroup analysis suggested enhanced efficacy in patients with prior endoscopic sinonasal surgery. CONCLUSIONS: ETI therapy demonstrates comprehensive improvements in CRS and olfactory function in CF patients, highlighting the potential of CFTR modulators in managing sinonasal manifestations.

Case Series: Hyperbilirubinemia under elexacaftor/tezacaftor/ivacaftor in the presence of Gilbert's syndrome.

Liver-related side effects are a known complication of treatment with elexacaftor/tezacaftor/ivacaftor (ETI) for cystic fibrosis (CF). Gilbert's syndrome is caused by a genetic mutation that reduces activity of the enzyme UDP glucuronosyltransferase 1 polypeptide A1 (UGT1A1), causing elevated levels of unconjugated bilirubin in the blood and duodenal bile. The presence of Gilbert's syndrome and CF might represent additive risk factors for liver-related adverse events during ETI treatment. This case series describes six people with CF (pwCF) in whom previously unknown Gilbert's syndrome was unmasked after initiation of treatment with ETI. Although all patients had some level of hepatic dysfunction and/or elevated levels of bilirubin after initiation of ETI, the clinical course varied. Only one patient had to stop ETI therapy altogether, while the others were able to continue treatment (some at a reduced dosage and others at the full recommended daily dosage). All patients, even those using a lower dosage, experienced clinical benefit during ETI therapy. Gilbert's syndrome is not a contraindication for ETI therapy but may be mistaken for a risk factor for liver-related adverse events in pwCF. This is something that physicians need to be aware of in pwCF who show liver adverse events during ETI therapy.

Assessing the impact of elexacaftor/tezacaftor/ivacaftor on anxiety & depression symptom scores in adults with Cystic Fibrosis.

The mental health effects of elexacaftor/tezacaftor/ivacaftor (ETI) on adults with CF are still uncertain with mixed findings from published studies. To systematically investigate the impact of ETI on symptoms of anxiety and depression in adults with CF, Generalized Anxiety Disorder-7 (GAD-7) and Patient Health Questionnaire (PHQ-9) scores were evaluated at baseline, 6 months, and 12 months post-ETI. Overall, GAD-7 and PHQ-9 scores improved at 6 months post-ETI, with a greater proportion of individuals experiencing a clinically significant improvement (vs. worsening) of their symptoms, which was sustained at 12 months. Factors influencing mental health outcomes included pre-existing psychiatric diagnoses and psychiatric medication use. In conclusion, although there was overall improvement in anxiety and depression symptoms post-ETI, approximately 10 % of individuals experienced clinically significant worsening.

Nasal Epithelium Transcriptomics Predict Clinical Response to Elexacaftor/Tezacaftor/Ivacaftor.

Elexacaftor/tezacaftor/ivacaftor (ETI) has made a substantial positive impact for people living with CF (pwCF). However, there can be substantial variability in efficacy, and we lack adequate biomarkers to predict individual response. We thus aimed to identify transcriptomic profiles in nasal respiratory epithelium that predict clinical response to ETI treatment. We obtained nasal epithelial samples from pwCF prior to ETI initiation and performed a transcriptome-wide analysis of baseline gene expression to predict changes in FEV1 (∆FEV1), year's best FEV1 (∆ybFEV1), and body mass index (∆BMI). Using the top differentially expressed genes (DEGs), we generated transcriptomic risk scores (TRS) and evaluated their predictive performance. The study included 40 pwCF aged ≥6 years (mean 27.7 [SD=15.1] years; 40% female). After ETI initiation, FEV1 improved ≥5% in 22 (61.1%) participants and ybFEV1 improved ≥5% in 19 (50%). TRS were constructed using top over-expressed and under-expressed genes for each. Adding the ∆FEV1 TRS for to a model with age, sex, and baseline FEV1 increased the AUC from 0.41 to 0.88; the ∆ybFEV1 TRS increased the AUC from 0.51 to 0.88; and the ∆BMI TRS increased the AUC from 0.46 to 0.92. Average accuracy was thus ~85% in predicting the response to the three outcomes. Results were similar in models further adjusted for F508del zygosity and previous CFTR modulator use. In conclusion, we identified nasal epithelial transcriptomic profiles that help accurately predict changes in FEV1 and BMI with ETI treatment. These novel TRS could serve as predictive biomarkers for clinical response to modulator treatment in pwCF.

Liver biochemical indexes and cholesterol metabolism in cystic fibrosis patients with F508del/CFTR variant genotype after elexacaftor/tezacaftor/ivacaftor treatment.

Modulators of cystic fibrosis transmembrane conductance regulator (CFTR) improved cystic fibrosis (CF) patients' outcome. The elexacaftor/tezacaftor/ivacaftor (ETI) combination was safe and effective improving lung function in patients with different CFTR genotypes, including at least one F508del mutation. However, cases with liver damage were reported. We describe 105 CF patients heterozygous for F508del in trans with another CFTR mutation, treated for 1 year with ETI. We analyzed liver biochemical parameters and cholesterol metabolism, including lathosterol and phytosterols, surrogate markers of cholesterol de-novo synthesis and absorption, respectively. The treatment significantly improved sweat chloride, body mass index and forced expiratory volume in 1 s, whereas it caused a significant increase of total and conjugated bilirubin, ALT and GGT, even if no patients developed CF liver disease. Such alterations were less relevant than those previously observed in ETI-treated F508del homozygous patients. Furthermore, ETI treatment significantly increased serum cholesterol by enhancing its absorption (correlation between serum cholesterol and phytosterols). Whereas, we observed a normalization of de-novo biosynthesis (lathosterol reduction) that was not observed in homozygous patients. These data suggest that the second mutation in trans with the F508del contributes to reduce the liver cholesterol accumulation and thus, the triggering of liver inflammation. However, no differences in the alteration of biochemical indexes were observed between CF patients with and without liver steatosis, and between patients with different mutations in trans with the F508del. Such data suggest to further investigate the effects of ETI therapy on liver function indexes and new predictive biomarkers.

The clinical effectiveness of elexacaftor/tezacaftor/ivacaftor (ETI) for people with CF without a F508del variant: A systematic review and meta-analysis.

BACKGROUND: Access to elexacaftor/tezacaftor/ivacaftor (ETI) for people with cystic fibrosis (PwCF) without a F508del variant is limited due to lack of clinical data supporting efficacy. METHODS: In this systematic review and meta-analysis, we examined patient-level data from studies reporting the clinical response to ETI for PwCF with non-F508del CFTR variants. We searched electronic data sources including Embase, MEDLINE, and CENTRAL from January 1st, 2019 to May 14th, 2024. FINDINGS: Our search results identified 4,795 studies and 20 met the eligibility criteria. 120 of 164 (73 %) individuals had a positive clinical response to ETI, defined by a sweat chloride (SwCl) decrease of ≥10 mmol/L or percent-predicted FEV1 (ppFEV1) improvement of ≥5 %. 51 unique ETI-responsive variants were represented across these 120 individuals and 27 of these variants (53 %) have not been previously approved by the U.S. FDA. For variants with at least 10 individuals treated with ETI to date, a consistent positive clinical response was observed for N1303K and G85E. For N1303K (n = 48), the median increase in ppFEV1 was 16 % (IQR: 8 %, 29 %), with a median decrease in SwCl of -9 (IQR: -4, -22) mmol/L. For G85E (n = 16), the median increase in ppFEV1 was 13.5 % (IQR: 8 %, 19 %) with a median decrease in SwCl of -46 (IQR: -39, -66) mmol/L. CONCLUSION: Additional ETI-responsive variants were identified following a comprehensive review of ETI clinical use in PwCF without F508del. This data can be used by the CF community in efforts to expand the labelled indications or to help advocate for off-label ETI reimbursement.

A case of severe pulmonary exacerbation in a young patient with cystic fibrosis in the era of CFTR modulators.

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 haemoptysis, 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.

Lung transplant list withdrawal in a liver transplant patient thanks to elexacaftor-tezacaftor-ivacaftor: a case report.

BACKGROUND: Elexacaftor-tezacaftor-ivacaftor (ETI) is a transmembrane conductance regulator modulator that significantly improves lung function in patients affected by cystic fibrosis (CF). This triple drug is currently not indicated in liver transplant patients, as clinical trials including subjects with previous solid organ transplantation are lacking. CASE PRESENTATION: We report on a liver transplant girl with CF-related advanced pulmonary disease meeting clinical criteria for lung transplant, who started the triple modulator because she could not get on the lung transplant waiting list due to psycho-social motivations. Since initiation of ETI therapy, she has experienced a significant improvement in respiratory function and quality of life, without adverse effects. CONCLUSIONS: This case shows that ETI therapy can represent a lifesaving drug for individuals without alternatives, even in liver transplant patients. The clinical benefits of the modulator overcome risks, which may be limited with a close drug monitoring of immunosuppressants serum levels and functional liver tests.

Cystic fibrosis: desensitization in delayed hypersensitivity reactions to elexacaftor/tezacaftor/ivacaftor.

Background: Cystic fibrosis transmembrane conductance regulator modulators are the only available treatment for cystic fibrosis. Although elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) is well-tolerated, rash has been reported as very frequent. In severe rashes, ELX/TEZ/IVA withdrawal is necessary, leading to clinical deterioration. The objective of the study is to increment the experience of ELX/TEZ/IVA desensitization. Methods: Adult patients who developed a delayed hypersensitivity rash to ELX/TEZ/IVA between December 2021 and February 2023 and required withdrawal due to ineffective rescue medication were included. Skins test for ELX/TEZ/IVA and IVA were conducted to establish hypersensitivity mechanism. Balijepally ELX/TEZ/IVA desensitization protocol was selected. In cases where desensitization had to be discontinued due to rash, an extended desensitization was proposed. Clinical and health-related quality of life parameters were collected before ELX/TEZ/IVA and after desensitization. Results: 162 patients (81 women, 31.2 [23.8-42.5] years) started ELX/TEZ/IVA, developing rash 12 of them (7.4%, six women). Six patients (five women) required stopping ELX/TEZ/IVA and were selected for desensitization. Skin tests indicated delayed type-IV hypersensitivity in one patient. Two patients presented adequate tolerance to desensitization; while, four patients developed rash. Three of these patients, successfully concluded extended desensitization (one patient declined participation). No significant clinical deterioration or quality of life worsening was observed during desensitization; in fact, there was an improvement in practically all mesured parameters. All five patients who resumed ELX/TEZ/IVA are currently receiving therapy with good tolerance. Conclusion: Desensitization to ELX/TEZ/IVA could be a successful and safe strategy for reintroducing this essential treatment in cases of a delayed hypersensitivity rash.

Effectiveness and safety of elexacaftor/tezacaftor/ivacaftor treatment in children aged 6-11 years with cystic fibrosis in a real-world setting.

BACKGROUND: Elexacaftor-tezacaftor-ivacaftor (ETI) is a highly effective cystic fibrosis (CF) transmembrane conductance regulator (CFTR) modulating therapy for people with CF and at least one F508del variant. However, there is limited data about the safety and efficacy of this therapy in pediatric populations and in real-world settings. This study aimed at evaluating the effectiveness, tolerability, and safety of ETI in children with CF. METHODS: This was a prospective observational study including all children aged 6-11 years who initiated ETI therapy between October 2022 and March 2023 at the Pediatric CF Center of Milan (Italy). Study outcomes included changes in sweat chloride concentration, FEV1, LCI2.5, body mass index (BMI), tolerance, and safety. Mean changes in study outcomes from baseline through 24 weeks were estimated using mixed-effects regression models. RESULTS: The study included 34 children with CF (median age: 8.3 years). At Week 12, we observed an average decrease in LCI2.5 of 2.3 units (95% confidence interval [CI]: -3.1; -1.5). At Week 24, sweat chloride concentration decreased by 63 mEq/L (95% CI: -69; -58), FEV1 increased by 8.8 percentage point (95% CI: 3.7; 13.9) and BMI increased by 0.15 standard deviation scores (95% CI: 0.04; 0.25). Skin rashes appeared in 6 patients which spontaneously resolved within a few days. One month after treatment initiation, one patient experienced an elevation in liver function test results, which subsequently decreased during follow-up visits without necessitating discontinuation of therapy. CONCLUSIONS: Our data indicate that ETI therapy is well tolerated by children with CF and is effective in improving signs of lung function abnormalities from early childhood.

Clinical and radiological improvement of cavitary Mycobacteroides abscessus disease in cystic fibrosis following initiation of elexacaftor/tezacaftor/ivacaftor.

Elexacaftor/tezacaftor/ivacaftor (ETI) is a CFTR modulator therapy that has dramatically improved the health outcomes for many people with cystic fibrosis (pwCF). There is increasing interest in the role of CFTR modulators in the prevention and treatment of respiratory infections in pwCF. A male patient with F508del homozygous cystic fibrosis developed cavitary Mycobacteroides abscessus subspecies bolletii & massiliense respiratory infection. Antimycobacterial treatment was not given as, in discussion with the patient's family, it was deemed unlikely that the intensive regimen would be tolerated by the patient on account of his autism spectrum disorder. Following initiation of ETI, there was a rapid clinical and radiological improvement in this patient's cavitary lung disease. This case adds to the evidence base that suggests CFTR modulators, particularly ETI, may restore innate immune function leading to improved outcomes for pulmonary infection in pwCF.

Pharmacokinetic variability of CFTR modulators from standard and alternative regimens.

Elexacaftor, tezacaftor, ivacaftor (ETI) is a CFTR modulator combination approved for use in ∼90 % of people with cystic fibrosis (pwCF) over 2 years old. While most pwCF tolerate this therapy well, some are intolerant to standard dosing, and others show little response. Clinical providers may adjust ETI dosing to combat these issues, but these adjustments are not well guided by pharmacokinetic evidence. Our post-approval study aimed to describe pharmacokinetic variability of ETI plasma concentrations in 15 participants who were administered a standard or reduced dose. ETI were quantified by LC-MS/MS in plasma samples taken prior to the morning dose. Results showed non-significant differences for each compound regardless of dosing regimen and after dose equivalence normalization. The majority of participants in both dosing groups had concentrations expected to elicit clinical response to ETI therapy. These findings indicate that dose reduction may be a viable strategy to maintain clinical benefit while managing intolerance.

Extent of foetal exposure to maternal elexacaftor/tezacaftor/ivacaftor during pregnancy.

BACKGROUND AND PURPOSE: Cystic fibrosis (CF) patients are living longer and healthier due to improved treatments, e.g. cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapy elexacaftor/tezacaftor/ivacaftor (ETI), with treatment possibly occurring in pregnancy. The risk of ETI to foetuses remain unknown. Thus the effect of maternally administered ETI on foetal genetic and structural development was investigated. EXPERIMENTAL APPROACH: Pregnant Sprague Dawley rats were orally treated with ETI (6.7 mg·kg-1·day-1 elexacaftor + 3.5 mg·kg-1·day-1 tezacaftor + 25 mg·kg-1·day-1 ivacaftor) for 7 days from E12 to E19. Tissue samples collected at E19 were analysed using histology and RNA sequencing. Histological changes and differentially expressed genes (DEG) were assessed. KEY RESULTS: No overt structural abnormalities were found in foetal pancreas, liver, lung and small intestine after 7-day ETI exposure. Very few non-functionally associated DEG in foetal liver, lung and small intestine were identified using RNA-seq. 29 DEG were identified in thymus (27 up-regulated and two down-regulated) and most were functionally linked to each other. Gene ontology enrichment analysis revealed that multiple muscle-related terms were significantly enriched. Many more DEG were identified in cortex (44 up-regulated and four down-regulated) and a group of these were involved in central nervous system and brain development. CONCLUSION AND IMPLICATION: Sub-chronic ETI treatment in late pregnancy does not appear to pose a significant risk to the genetic and structural development of many foetal tissues. However, significant gene changes in foetal thymic myoid cells and cortical neuronal development requires future follow-up studies to assess the risk to these organs.

The long-term effect of elexacaftor/tezacaftor/ivacaftor on cardiorespiratory fitness in adolescent patients with cystic fibrosis: a pilot observational study.

BACKGROUND: Physical activity is a crucial demand on cystic fibrosis treatment management. The highest value of oxygen uptake (VO2peak) is an appropriate tool to evaluate the physical activity in these patients. However, there are several other valuable CPET parameters describing exercise tolerance (Wpeak, VO2VT1, VO2VT2, VO2/HRpeak, etc.), and helping to better understand the effect of specific treatment (VE, VT, VD/VT etc.). Limited data showed ambiguous results of this improvement after CFTR modulator treatment. Elexacaftor/tezacaftor/ivacaftor medication improves pulmonary function and quality of life, whereas its effect on CPET has yet to be sufficiently demonstrated. METHODS: We performed a single group prospective observational study of 10 adolescent patients with cystic fibrosis who completed two CPET measurements between January 2019 and February 2023. During this period, elexacaftor/tezacaftor/ivacaftor treatment was initiated in all of them. The first CPET at the baseline was followed by controlled CPET at least one year after medication commencement. We focused on interpreting the data on their influence by the novel therapy. We hypothesized improvements in cardiorespiratory fitness following treatment. We applied the Wilcoxon signed-rank test. The data were adjusted for age at the time of CPET to eliminate bias of aging in adolescent patients. RESULTS: We observed significant improvement in peak workload, VO2 peak, VO2VT1, VO2VT2, VE/VCO2 slope, VE, VT, RQ, VO2/HR peak and RR peak. The mean change in VO2 peak was 5.7 mL/kg/min, or 15.9% of the reference value (SD ± 16.6; p= 0.014). VO2VT1 improved by 15% of the reference value (SD ± 0.1; p= 0.014), VO2VT2 improved by 0.5 (SD ± 0.4; p= 0.01). There were no differences in other parameters. CONCLUSION: Exercise tolerance improved after elexacaftor/tezacaftor/ivacaftor treatment initiation. We suggest that the CFTR modulator alone is not enough for recovering physical decondition, but should be supplemented with physical activity and respiratory physiotherapy. Further studies are needed to examine the effect of CFTR modulators and physical therapy on cardiopulmonary exercise tolerance.

Heterogeneity in response to Elexacaftor/Tezacaftor/Ivacaftor in people with cystic fibrosis.

BACKGROUND: Highly effective modulators of the CFTR channel have been demonstrated to dramatically impact disease progression and outcome. However, real-world data indicates that the magnitude of the clinical benefit is not equal among all patients receiving the treatment. We aimed to assess the variability in treatment response (as defined by the 6-month change in sweat chloride concentration, forced expiratory volume in one second [ppFEV1], body mass index [BMI], and CF Questionnaire-Revised [CFQ-R] respiratory domain score) and identify potential predictors in a group of patients receiving Elexacaftor-Tezacaftor-Ivacaftor (ETI) triple combination therapy. METHODS: This was a single-center, prospective cohort study enrolling adults with CF at a major center in Italy. We used linear regression models to identify a set of potential predictors (including CFTR genotype, sex, age, and baseline clinical characteristics) and estimate the variability in treatment response. RESULTS: The study included 211 patients (median age: 29 years, range: 12-58). Median changes (10-90th percentile) from baseline were: - 56 mEq/L (-76; -27) for sweat chloride concentration, +14.5 points (2.5; 32.0) for ppFEV1, +0.33 standard deviation scores (-0.13; 1.05) for BMI and +17 points (0; 39) for the CFQ-R respiratory domain score. The selected predictors explained 23 % of the variability in sweat chloride concentration changes, 18 % of the variability in ppFEV1 changes, 39 % of the variability in BMI changes, and 65 % of the variability in CFQ-R changes. CONCLUSIONS: This study highlights a high level of heterogeneity in treatment response to ETI, which can only be partially explained by the baseline characteristics of the disease.

Tezacaftor is a direct inhibitor of sphingolipid delta-4 desaturase enzyme (DEGS).

BACKGROUND: We recently demonstrated that 48 h exposure of primary human bronchial epithelial (hBE) cells, obtained from both CF (F508del homozygous) and non-CF subjects, to the triple drug combination Elexacaftor/Tezacaftor/Ivacaftor (ETI) results in a CFTR genotype-independent modulation of the de novo synthethic pathway of sphingolipids, with an accumulation of dihydroceramides (dHCer). Since dHCer are converted into ceramides (Cer) by the action of a delta-4 sphingolipid desaturase (DEGS) enzyme, we aimed to better understand this off-target effect of ETI (i.e., not related to CFTR rescue) METHODS: hBE cells, both F508del and wild-type, were cultured to create fully differentiated bronchial epithelia. We analyzed Cer and dHCer using an LC-MS based method previously developed by our lab. DEGS expression levels in differentiated hBE cells lysates were quantified by western blot analysis. RESULTS: We demonstrated that 1) dHCer accumulate in hBE with time following prolonged ETI exposure, that 2) similar inhibition occurs in wild-type primary human hepatocytes and that 3) this does not result in an alteration of DEGS expression. We then proved that 4) ETI is a direct inhibitor of DEGS, that 5) Tezacaftor is the molecule responsible for this effect, that 6) the inhibition is concentration dependent. Finally, after repeated oral administration of ETI to naïve, non-CF, mice, we observed a slight accumulation of dHCer in the brain. CONCLUSIONS: We believe that further investigations on Tezacaftor should be envisaged, particularly for the use of ETI during pregnancy, breastfeeding and in the early stages of development. DEGS dysfunction and dHCer accumulation causes impairment in the development of the nervous system, due to a derangement in myelin formation and maintenance.

Elexacaftor/Tezacaftor/Ivacaftor use in Pediatric Cystic Fibrosis Patients with Advanced Liver Disease.

BACKGROUND: Cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapy extends the life expectancy of people with cystic fibrosis (PwCF). However, CFTR modulators have not been well studied in patients with cystic fibrosis liver disease (CFLD), specifically those with advanced liver disease with portal hypertension. The purpose of this report is to describe the use of elexacaftor/tezacaftor/ivacaftor (ETI) in pediatric CF patients with advanced CFLD. METHODS: This retrospective case series included PwCF < 18 years old with baseline advanced CFLD initiated on ETI. RESULTS: Eleven PwCF and advanced CFLD were treated with ETI; six started a reduced dose regimen. No patient required treatment interruption and four patients received dose changes related to increase in transaminase and/or bilirubin elevations. Mean (SD) change in ppFEV1 from prior to ETI to highest value during therapy was 14.27 % (4.25) (p = 0.007). When evaluating the group as whole, AST decreased from baseline to last reported -15.18 (23.23) units/L (p = 0.054) and ALT slightly increased 0.73 (39.13) units/L (p = 0.96). Bilirubin increased minimally overall for patients with mean change from baseline of 0.83 (1.33) mg/dL [range -0.5-3] (p = 0.17). A model for time on ETI showed a significant decrease in AST over time of 0.955 per month of ETI but no other liver biochemistries were significant. No patient experienced decompensation of CFLD. CONCLUSION: ETI therapy in pediatric CF patients with advanced CFLD can be beneficial in improving pulmonary and nutritional outcomes without negative impact on liver biochemistries or hepatic outcomes. Close monitoring is recommended to ensure safety and tolerability.

Real-world effectiveness of elexacaftor/tezacaftor/ivacaftor on the burden of illness in adolescents and adults with cystic fibrosis.

Background: Elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) has been shown to be safe and efficacious in people with cystic fibrosis (CF) aged ≥2 years. Here, we describe results from an observational study assessing change in burden of illness following initiating ELX/TEZ/IVA in real-world settings. Methods: This US-based, multicenter, observational study used data from electronic medical records to evaluate real-world burden of illness before and after ELX/TEZ/IVA initiation in people with CF aged ≥12 years heterozygous for F508del and a minimal function mutation (F/MF) or an uncharacterized CFTR mutation. Endpoints included absolute change from baseline in percent predicted forced expiratory volume in 1 s (ppFEV1), body mass index (BMI) and BMI-for-age z-score, glycated hemoglobin (HbA1c), and numbers of pulmonary exacerbations (PEx). Results: Overall, 206 people with CF were enrolled (mean [SD] age 22.5 [11.1] years; 192 [93.2%] with F/MF genotype). Mean follow-up was 15.6 (SD, 1.6) months. Improvements in ppFEV1 (7.3 [95% CI: 5.7, 8.8] percentage points) were observed from baseline through follow-up. Increases in BMI (1.40 [95% CI: 1.07, 1.77] kg/m2) and BMI-for-age z-score (0.14 [95% CI: 0.00, 0.28]) were also observed from baseline at 12 months. The estimated annualized rate of any PEx was 1.31 at baseline and 0.61 over follow-up (rate ratio 0.47 [95% CI: 0.39, 0.55]), with annualized rates of PEx requiring antibiotics and hospitalizations of 0.55 and 0.88 in the baseline period and 0.12 and 0.36 over follow-up (rate ratios 0.22 [95% CI: 0.15, 0.31] and 0.41 [95% CI: 0.32, 0.51]), respectively. Absolute change in HbA1c was -0.22 (95% CI: -0.38, -0.06) from baseline through follow-up. Conclusions: ELX/TEZ/IVA treatment was associated with improved lung function, increased BMI, reduced frequency of PEx, and improved (i.e., reduced) HbA1c. These results confirm the broad clinical benefits of ELX/TEZ/IVA seen in clinical trials and show the potential for ELX/TEZ/IVA to improve markers of glucose metabolism.