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Eastman AC, Rosson G, Kim N, Kang S, Raraigh K, Goff LA, Merlo C, Lechtzin N, Cutting GR, Sharma N. Establishment of a conditionally reprogrammed primary eccrine sweat gland culture for evaluation of tissue-specific CFTR function. J Cyst Fibros 2024:S1569-1993(24)00783-5. [PMID: 38969603 DOI: 10.1016/j.jcf.2024.06.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 04/30/2024] [Accepted: 06/25/2024] [Indexed: 07/07/2024]
Abstract
BACKGROUND Sweat chloride concentration is used both for CF diagnosis and for tracking CFTR modulator efficacy over time, but the relationship between sweat chloride and lung health is heterogeneous and informed by CFTR genotype. Here, we endeavored to characterize ion transport in eccrine sweat glands (ESGs). METHODS First, ESGs were microdissected from a non-CF skin donor to analyze individual glands. We established primary cultures of ESG cells via conditional reprogramming for functional testing of ion transport by short circuit current measurement and examined cell composition by single-cell RNA-sequencing (scRNA-seq) comparing with whole dissociated ESGs. Secondly, we cultured nasal epithelial (NE) cells and ESGs from two people with CF (pwCF) to assess modulator efficacy. Finally, NEs and ESGs were grown from one person with the CFTR genotype F312del/F508del to explore genotype-phenotype heterogeneity. RESULTS ESG primary cells from individuals without CF demonstrated robust ENaC and CFTR function. scRNA-seq demonstrated both secretory and ductal ESG markers in cultured ESG cells. In both NEs and ESGs from pwCF homozygous for F508del, minimal baseline CFTR function was observed, and treatment with CFTR modulators significantly enhanced function. Notably, NEs from an individual bearing F312del/F508del exhibited significant baseline CFTR function, whereas ESGs from the same person displayed minimal CFTR function, consistent with observed phenotype. CONCLUSIONS This study has established a novel primary culture technique for ESGs that allows for functional ion transport measurement to assess modulator efficacy and evaluate genotype-phenoytpe heterogeneity. To our knowledge, this is the first reported application of conditional reprogramming and scRNA-seq of microdissected ESGs.
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Affiliation(s)
- Alice C Eastman
- Johns Hopkins School of Medicine, Department of Human Genetics, Miller Research Building, 733N Broadway, Baltimore, MD 21205, USA
| | - Gedge Rosson
- Johns Hopkins Medicine, Department of Plastic and Reconstructive Surgery, 601N Caroline St, Baltimore, MD 21287, USA
| | - Noori Kim
- Johns Hopkins School of Medicine, Department Medicine, Division of Dermatology, 601N Caroline St, Baltimore, MD 21287, USA
| | - Sewon Kang
- Johns Hopkins School of Medicine, Department Medicine, Division of Dermatology, 601N Caroline St, Baltimore, MD 21287, USA
| | - Karen Raraigh
- Johns Hopkins School of Medicine, Department of Human Genetics, Miller Research Building, 733N Broadway, Baltimore, MD 21205, USA
| | - Loyal A Goff
- Johns Hopkins School of Medicine, Department of Human Genetics, Miller Research Building, 733N Broadway, Baltimore, MD 21205, USA
| | - Christian Merlo
- Johns Hopkins University School of Medicine, Department of Medicine, Division of Pulmonary and Critical Care Medicine, 1800 Orleans St, Baltimore, MD 21287, USA
| | - Noah Lechtzin
- Johns Hopkins University School of Medicine, Department of Medicine, Division of Pulmonary and Critical Care Medicine, 1800 Orleans St, Baltimore, MD 21287, USA
| | - Garry R Cutting
- Johns Hopkins School of Medicine, Department of Human Genetics, Miller Research Building, 733N Broadway, Baltimore, MD 21205, USA
| | - Neeraj Sharma
- Johns Hopkins School of Medicine, Department of Human Genetics, Miller Research Building, 733N Broadway, Baltimore, MD 21205, USA.
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Alicandro G, Gramegna A, Bellino F, Sciarrabba SC, Lanfranchi C, Contarini M, Retucci M, Daccò V, Blasi F. Heterogeneity in response to Elexacaftor/Tezacaftor/Ivacaftor in people with cystic fibrosis. J Cyst Fibros 2024:S1569-1993(24)00057-2. [PMID: 38729849 DOI: 10.1016/j.jcf.2024.04.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 02/27/2024] [Accepted: 04/24/2024] [Indexed: 05/12/2024]
Abstract
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.
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Affiliation(s)
- Gianfranco Alicandro
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy; Department of Paediatrics, Cystic Fibrosis Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Andrea Gramegna
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy; Respiratory Unit and Cystic Fibrosis Adult Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
| | - Federica Bellino
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy; Respiratory Unit and Cystic Fibrosis Adult Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Sathya Calogero Sciarrabba
- Department of Paediatrics, Cystic Fibrosis Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Chiara Lanfranchi
- Department of Paediatrics, Cystic Fibrosis Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Martina Contarini
- Respiratory Unit and Cystic Fibrosis Adult Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Mariangela Retucci
- Respiratory Unit and Cystic Fibrosis Adult Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy; Healthcare Professions Department, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Valeria Daccò
- Department of Paediatrics, Cystic Fibrosis Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Francesco Blasi
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy; Respiratory Unit and Cystic Fibrosis Adult Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
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3
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Hong E, Parsons SM, Sass L, Epstein C, Chan L, Brown C, Eshaghian PH, Beringer PM. Preliminary evidence for sustained efficacy of CFTR modulator therapy with concomitant rifabutin administration. J Cyst Fibros 2024; 23:519-523. [PMID: 38036321 DOI: 10.1016/j.jcf.2023.11.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 10/22/2023] [Accepted: 11/24/2023] [Indexed: 12/02/2023]
Abstract
The concomitant use of elexacaftor/tezacaftor/ivacaftor (ETI) and strong CYP3A inducers including rifampin and rifabutin is not recommended due to the risk of drug-drug interactions (DDI). This presents a significant challenge to the treatment of non-tuberculous mycobacteria precluding the first line treatment. While rifabutin induces CYP3A activity, its effect appears to be moderate compared to rifampin. In this study, we investigated three cases in which concomitant use of rifabutin and CFTR modulators (ETI or ivacaftor monotherapy) was used, and these cases suggest that addition of rifabutin did not compromise the efficacy of ETI or ivacaftor as evidenced by pulmonary function and sweat chloride testing. A full physiologically based pharmacokinetic model predicted lung concentrations of ETI upon rifabutin coadministration to exceed the half-maximal effective concentrations (EC50) determined from chloride transport in phe508del human bronchial epithelial cells. This study provides preliminary evidence in support of the use of rifabutin in patients receiving ETI.
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Affiliation(s)
- Eunjin Hong
- Department of Clinical Pharmacy, Mann School of Pharmacy and Pharmaceutical Sciences, University of Southern California, 1985 Zonal Ave, Los Angeles, CA 90033, United States; College of Pharmacy, CHA University, 335 Pangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi-do, 13488, South Korea
| | - Sarah M Parsons
- Children's Hospital of The King's Daughters, 601 Children's Ln, Norfolk, VA 23507, United States
| | - Laura Sass
- Children's Hospital of The King's Daughters, 601 Children's Ln, Norfolk, VA 23507, United States
| | - Cynthia Epstein
- Children's Hospital of The King's Daughters, 601 Children's Ln, Norfolk, VA 23507, United States
| | - Lynn Chan
- Department of Pharmaceutical Services, University of California Los Angeles, 757 Westwood Plaza, Los Angeles, CA 90095, United States
| | - Claire Brown
- Division of Infectious Diseases, University of California Los Angeles, 757 Westwood Plaza, Los Angeles, CA 90095, United States
| | - Patricia H Eshaghian
- Division of Pulmonary and Critical Care Medicine, University of California Los Angeles, 1260 15(th) St #600, Santa Monica, CA 90404, United States
| | - Paul M Beringer
- Department of Clinical Pharmacy, Mann School of Pharmacy and Pharmaceutical Sciences, University of Southern California, 1985 Zonal Ave, Los Angeles, CA 90033, United States; USC Anton Yelchin CF Clinic, 1510 San Pablo St, Los Angeles, CA 90033, United States.
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Vonk SEM, Altenburg J, Mathôt RAA, Kemper EM. Correlation between trough concentration and AUC for elexacaftor, tezacaftor and ivacaftor. J Cyst Fibros 2024:S1569-1993(24)00038-9. [PMID: 38494378 DOI: 10.1016/j.jcf.2024.03.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 03/08/2024] [Accepted: 03/09/2024] [Indexed: 03/19/2024]
Abstract
Therapeutic drug monitoring (TDM) of elexacaftor, tezacaftor, ivacaftor (ETI) could be a useful tool to increase efficacy and decrease the risk of adverse effects in people with Cystic Fibrosis (pwCF). It is however unclear whether drug exposure should be monitored by assessment of trough (Cmin) levels or determination of the area under the curve (AUC). Hence, in this study the correlation between measured Cmin concentration and AUC was evaluated. Serial plasma samples, including Cmin, were drawn after administration of ETI in order to calculate the AUC and assess the correlation between the two parameters. A linear correlation between Cmin and AUC0-24h was found, with Pearson's r correlation coefficients of 0.963, 0.908 and 0.860 for elexacaftor, tezacaftor and ivacaftor, respectively. Exposure of ETI may be monitored by assessment of Cmin levels.
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Affiliation(s)
- Steffie E M Vonk
- Amsterdam UMC location University of Amsterdam, Department of Hospital Pharmacy & Clinical Pharmacology, Meibergdreef 9, Amsterdam, the Netherlands.
| | - Josje Altenburg
- Amsterdam UMC location University of Amsterdam, Department of Pulmonary Medicine, Meibergdreef 9, Amsterdam, the Netherlands
| | - Ron A A Mathôt
- Amsterdam UMC location University of Amsterdam, Department of Hospital Pharmacy & Clinical Pharmacology, Meibergdreef 9, Amsterdam, the Netherlands
| | - E Marleen Kemper
- Amsterdam UMC location University of Amsterdam, Department of Hospital Pharmacy & Clinical Pharmacology, Meibergdreef 9, Amsterdam, the Netherlands; Amsterdam UMC location University of Amsterdam, Department of Vascular Medicine, Amsterdam, the Netherlands
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5
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Sawicki GS, Wicha WW, Hiley TS, Close NC, Gelone SP, Guico-Pabia CJ. Safety and Pharmacokinetics Following Oral or Intravenous Lefamulin in Adults With Cystic Fibrosis. Clin Ther 2024; 46:96-103. [PMID: 38195348 DOI: 10.1016/j.clinthera.2023.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 10/27/2023] [Accepted: 12/03/2023] [Indexed: 01/11/2024]
Abstract
PURPOSE Methicillin-resistant Staphylococcus aureus infections are increasing in prevalence in patients with cystic fibrosis (CF) and are associated with worsening lung function and increased mortality. Lefamulin is a pleuromutilin antimicrobial approved to treat community-acquired bacterial pneumonia based on potent in vitro activity and clinical efficacy. This Phase I, open-label, randomized crossover study assessed the safety and pharmacokinetic profile of oral and intravenous (IV) lefamulin in adults with CF. METHODS The study comprised 2 dosing periods in which adults with CF (N = 13) received a single dose of lefamulin via a 150-mg IV infusion or 600-mg immediate-release orally administered tablet, separated by a 4- to 7-day washout period. Pharmacokinetic and safety parameters were assessed after lefamulin treatment. FINDINGS Single doses of lefamulin administered via oral tablet or IV infusion resulted in comparable drug exposure, and sputum analysis suggested rapid penetration of lefamulin into the lung. Comparison of the present results with those obtained from prior single-dose studies of healthy volunteers indicate no meaningful difference in the pharmacokinetic properties of lefamulin in patients with CF. Treatment-emergent adverse events were consistent with previous reports, and the majority were mild in severity. IMPLICATIONS These results show similar lefamulin pharmacokinetic and safety profiles between patients with CF and healthy volunteers receiving the same oral and IV doses, suggesting no need for lefamulin dose adjustment in patients with CF and indicating the potential of lefamulin as therapy for lung infections in patients with CF. CLINICALTRIALS gov identifier: NCT05225805.
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Affiliation(s)
| | | | - Tara S Hiley
- Nabriva Therapeutics US, Inc, Fort Washington, Pennsylvania, USA
| | | | - Steven P Gelone
- Nabriva Therapeutics US, Inc, Fort Washington, Pennsylvania, USA
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Ali I, Kalkat A, Hostoffer R. Rapid desensitization to elexacaftor/tezacaftor/ivacaftor in a cystic fibrosis patient using fatty snack for improved absorption. Pediatr Pulmonol 2023; 58:2954-2955. [PMID: 37503879 DOI: 10.1002/ppul.26609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 06/02/2023] [Accepted: 07/12/2023] [Indexed: 07/29/2023]
Affiliation(s)
- Irfan Ali
- Cleveland Medical Center, University Hospitals, Cleveland, Ohio, USA
| | - Amanpreet Kalkat
- Cleveland Medical Center, University Hospitals, Cleveland, Ohio, USA
| | - Robert Hostoffer
- Cleveland Medical Center, University Hospitals, Cleveland, Ohio, USA
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7
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Hong E, Shi A, Beringer P. Drug-drug interactions involving CFTR modulators: a review of the evidence and clinical implications. Expert Opin Drug Metab Toxicol 2023; 19:203-216. [PMID: 37259485 DOI: 10.1080/17425255.2023.2220960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 05/30/2023] [Indexed: 06/02/2023]
Abstract
INTRODUCTION Cystic fibrosis (CF) is characterized by mucus accumulation impairing the lungs, gastrointestinal tract, and other organs. Cystic fibrosis transmembrane conductance regulator (CFTR) modulators (ivacaftor, tezacaftor, elexacaftor, and lumacaftor) significantly improve lung function and nutritional status; however, they are substrates, inhibitors, and/or inducers of certain CYP enzymes and transporters, raising the risk of drug-drug interactions (DDI) with common CF medications. AREAS COVERED A literature search was conducted for DDIs involving CFTR modulators by reviewing new drug applications, drug package inserts, clinical studies, and validated databases of substrates, inhibitors, and inducers. Clinically, CYP3A inducers and inhibitors significantly decrease and increase systemic concentrations of elexacaftor/tezacaftor/ivacaftor, respectively. Additionally, lumacaftor and ivacaftor alter concentrations of CYP3A and P-gp substrates. Potential DDIs without current clinical evidence include ivacaftor and elexacaftor's effect on CYP2C9 and OATP1B1/3 substrates, respectively, and OATP1B1/3 and P-gp inhibitors' effect on tezacaftor. A literature review was conducted using PubMed. EXPERT OPINION Dosing recommendations for CFTR modulators with DDIs are relatively comprehensive; however, recommendations on timing of dosing transition of CFTR modulators when CYP3A inhibitors are initiated or discontinued is incomplete. Certain drug interactions may be managed by choosing an alternative treatment to avoid/minimize DDIs. Next generation CFTR modulator therapies under development are expected to provide increased activity with reduced DDI risk.
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Affiliation(s)
- Eunjin Hong
- Department of Clinical Pharmacy, USC Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA, USA
| | - Alan Shi
- Department of Clinical Pharmacy, USC Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA, USA
| | - Paul Beringer
- Department of Clinical Pharmacy, USC Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA, USA
- USC Anton Yelchin CF Clinic, Los Angeles, CA, USA
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Simultaneous Quantification of Ivacaftor, Tezacaftor, and Elexacaftor in Cystic Fibrosis Patients' Plasma by a Novel LC-MS/MS Method. Biomedicines 2023; 11:biomedicines11020628. [PMID: 36831163 PMCID: PMC9953078 DOI: 10.3390/biomedicines11020628] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 02/10/2023] [Accepted: 02/16/2023] [Indexed: 02/22/2023] Open
Abstract
The new breakthrough cystic fibrosis (CF) drug combination of ivacaftor (IVA), tezacaftor (TEZ), and elexacaftor (ELX), namely "caftor" drugs, directly modulates the activity and trafficking of the defective CF transmembrane conductance regulator protein (CFTR) underlying the CF disease. The role of therapeutic drug monitoring (TDM) of caftor drugs in clinical settings has recently been established. The availability of reliable and robust analytical methods for the quantification of IVA, TEZ, and ELX is essential to support dose-concentration-effect studies. We have developed and validated a new liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the rapid and simultaneous quantification of IVA, TEZ, and ELX from the plasma of CF patients. The method was based on a rapid extraction protocol from 50 μL human plasma and separation on a reversed-phase C-18 HPLC column after the addition of deuterated internal standards. Accurate analyte quantification using multiple reaction monitoring (MRM) detection was then obtained using a Thermofisher Quantiva triple-quadrupole MS coupled to an Ultimate 3000 UHPLC. The method has been validated following international (EMA) guidelines for bioanalytical method validation and has been tested on plasma samples from 62 CF patients treated with the three-drug combination IVA/TEZ/ELX, marketed as Kaftrio® or Trikafta®, in steady-state condition. The assay was linear over wide concentration ranges (0.008-12 mg/L) in plasma for IVA, TEZ, and ELX, suitable for a broad range of plasma concentrations, and accurate and reproducible in the absence of matrix effects. The stability of analytes for at least 30 days at room temperature could allow for cost-effective shipment and storage. On the same day of sample collection, a sweat test was evaluated for 26 associated patients' samples, FEV1 (%) for 58, and BMI was calculated for 62. However, Spearman correlation showed no correlation between Cthrough plasma concentrations of analytes (IVA, TEZ, ELX) and sweat test, FEV1 (%), or BMI. Our method proved to be suitable for TDM and could be helpful in assessing dose-concentration-response correlations in larger studies.
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Terlizzi V, Centrone C, Ferrari B, Castellani C, Gunawardena TNA, Taccetti G, Laselva O. Modulator Therapy in Cystic Fibrosis Patients with cis Variants in F508del Complex Allele: A Short-Term Observational Case Series. J Pers Med 2022; 12:jpm12091421. [PMID: 36143206 PMCID: PMC9504164 DOI: 10.3390/jpm12091421] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 08/24/2022] [Accepted: 08/26/2022] [Indexed: 11/16/2022] Open
Abstract
Previous studies reported the influence of cis variants in F508del cystic fibrosis (CF) patients in their responses to CFTR modulators. The current study is a prospective, observational study involving three patients with CF and pancreatic insufficiency, carrying a complex allele including F508del with A238V, I1027T, or L467F. We report clinical data before and after 4 weeks of treatment with tezacaftor (TEZ)/ivacaftor (IVA), elexacaftor (ELX)/TEZ/IVA, and lumacaftor (LUM)/IVA for patients with complex alleles A238V, I1027T, and L467F, respectively. The 50-year-old patient bearing F508del;A238V/D1152H showed a normal sweat test (13 mEq/L) and improvements in forced expiratory volume in the first second (FEV1) (+7 points), body mass index (BMI) (+0.85), and respiratory CF Questionnaire-Revised (CFQ-R) domain (+22.2 points). The 12-year-old patient bearing F508del;I1027T/R709X showed an improvement in a sweat test (−40 mEq/l), FEV1 (+9 points) and the respiratory CFQ-R domain (+16.7 points). No changes in outcomes were observed for the 6-year-old patient F508del;L467F/F508del. Our data highlight that the reported variants do not modify the phenotypic expression of F508del. Searching L467F is crucial in CF patients with F508del nonresponsive to ELX/TEZ/IVA. Further data are needed to evaluate the clinical effect of these variants after a longer follow up.
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Affiliation(s)
- Vito Terlizzi
- Department of Paediatric Medicine, Cystic Fibrosis Regional Reference Center, Meyer Children’s Hospital, 50139 Florence, Italy
- Correspondence: (V.T.); (O.L.); Tel.: +39-0881588074 (O.L.)
| | - Claudia Centrone
- Diagnostic Genetics Unit, Careggi University Hospital, 50134 Florence, Italy
| | - Beatrice Ferrari
- Rehabilitation Unit, Meyer Children’s Hospital, 50139 Florence, Italy
| | - Chiara Castellani
- Department of Radiology, Meyer Children’s Hospital, 50139 Florence, Italy
| | - Tarini N. A. Gunawardena
- Programme in Molecular Medicine, The Hospital for Sick Children, Toronto, ON M5G 8X4, Canada
- Programme in Translational Medicine, The Hospital for Sick Children, Toronto, ON M5G 8X4, Canada
| | - Giovanni Taccetti
- Department of Paediatric Medicine, Cystic Fibrosis Regional Reference Center, Meyer Children’s Hospital, 50139 Florence, Italy
| | - Onofrio Laselva
- Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy
- Correspondence: (V.T.); (O.L.); Tel.: +39-0881588074 (O.L.)
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10
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Therapeutic Drug Monitoring of Ivacaftor, Lumacaftor, Tezacaftor, and Elexacaftor in Cystic Fibrosis: Where Are We Now? Pharmaceutics 2022; 14:pharmaceutics14081674. [PMID: 36015300 PMCID: PMC9412421 DOI: 10.3390/pharmaceutics14081674] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 07/20/2022] [Accepted: 07/23/2022] [Indexed: 11/16/2022] Open
Abstract
Drugs modulating the cystic fibrosis transmembrane conductance regulator (CFTR) protein, namely ivacaftor, lumacaftor, tezacaftor, and elexacaftor, are currently revolutionizing the management of patients with cystic fibrosis (CF), particularly those with at least one F508del variant (up to 85% of patients). These “caftor” drugs are mainly metabolized by cytochromes P450 3A, whose enzymatic activity is influenced by environmental factors, and are sensitive to inhibition and induction. Hence, CFTR modulators are characterized by an important interindividual pharmacokinetic variability and are also prone to drug–drug interactions. However, these CFTR modulators are given at standardized dosages, while they meet all criteria for a formal therapeutic drug monitoring (TDM) program that should be considered in cases of clinical toxicity, less-than-expected clinical response, drug or food interactions, distinct patient subgroups (i.e., pediatrics), and for monitoring short-term adherence. While the information on CFTR drug exposure–clinical response relationships is still limited, we review the current evidence of the potential interest in the TDM of caftor drugs in real-life settings.
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Abstract
Over the past decade there have been significant developments in the field of Cystic Fibrosis Transmembrane Regulator modulator drugs. Following treatment in patients with cystic fibrosis with common gating mutations using the potentiator drug ivacaftor, successive development of corrector drugs used in combination has led to highly effective modulator therapy being available to more than 85% of the cystic fibrosis population over 12 years of age in the form of elexacaftor/tezacaftor/ivacaftor. In this article, we review the evidence from clinical trials and mounting real-world observational and registry data that demonstrates the impact highly effective modulators have on both pulmonary and extra-pulmonary manifestations of cystic fibrosis. As clinical trials progress to younger patient groups, we discuss the challenges to demonstrating drug efficacy in early life, and also consider practicalities of drug development in an ever-shrinking modulator-naïve population. Drug-drug interactions are an important consideration in people with cystic fibrosis, where polypharmacy is commonplace, but also as the modulated population look to remain healthier for longer, we identify trials that aim to address treatment burden too. Inequity of care, through drug cost or ineligibility for modulators by genotype, is widening without apparent strategies to address this; however, we present evidence of hopeful early-stage drug development for non-modulatable genes and summarise the current state of gene-therapy development.
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12
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The L467F-F508del Complex Allele Hampers Pharmacological Rescue of Mutant CFTR by Elexacaftor/Tezacaftor/Ivacaftor in Cystic Fibrosis Patients: The Value of the Ex Vivo Nasal Epithelial Model to Address Non-Responders to CFTR-Modulating Drugs. Int J Mol Sci 2022; 23:ijms23063175. [PMID: 35328596 PMCID: PMC8952007 DOI: 10.3390/ijms23063175] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 03/10/2022] [Accepted: 03/14/2022] [Indexed: 12/16/2022] Open
Abstract
Loss-of-function mutations of the CFTR gene cause cystic fibrosis (CF) through a variety of molecular mechanisms involving altered expression, trafficking, and/or activity of the CFTR chloride channel. The most frequent mutation among CF patients, F508del, causes multiple defects that can be, however, overcome by a combination of three pharmacological agents that improve CFTR channel trafficking and gating, namely, elexacaftor, tezacaftor, and ivacaftor. This study was prompted by the evidence of two CF patients, compound heterozygous for F508del and a minimal function variant, who failed to obtain any beneficial effects following treatment with the triple drug combination. Functional studies on nasal epithelia generated in vitro from these patients confirmed the lack of response to pharmacological treatment. Molecular characterization highlighted the presence of an additional amino acid substitution, L467F, in cis with the F508del variant, demonstrating that both patients were carriers of a complex allele. Functional and biochemical assays in heterologous expression systems demonstrated that the double mutant L467F-F508del has a severely reduced activity, with negligible rescue by CFTR modulators. While further studies are needed to investigate the actual prevalence of the L467F-F508del allele, our results suggest that this complex allele should be taken into consideration as plausible cause in CF patients not responding to CFTR modulators.
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