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Heneghan M, Southern KW, Murphy J, Sinha IP, Nevitt SJ. Corrector therapies (with or without potentiators) for people with cystic fibrosis with class II CFTR gene variants (most commonly F508del). Cochrane Database Syst Rev 2023; 11:CD010966. [PMID: 37983082 PMCID: PMC10659105 DOI: 10.1002/14651858.cd010966.pub4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2023]
Abstract
BACKGROUND Cystic fibrosis (CF) is a common life-shortening genetic condition caused by a variant in the cystic fibrosis transmembrane conductance regulator (CFTR) protein. A class II CFTR variant F508del is the commonest CF-causing variant (found in up to 90% of people with CF (pwCF)). The F508del variant lacks meaningful CFTR function - faulty protein is degraded before reaching the cell membrane, where it needs to be to effect transepithelial salt transport. Corrective therapy could benefit many pwCF. This review evaluates single correctors (monotherapy) and any combination of correctors (most commonly lumacaftor, tezacaftor, elexacaftor, VX-659, VX-440 or VX-152) and a potentiator (e.g. ivacaftor) (dual and triple therapies). OBJECTIVES To evaluate the effects of CFTR correctors (with or without potentiators) on clinically important benefits and harms in pwCF of any age with class II CFTR mutations (most commonly F508del). SEARCH METHODS We searched the Cochrane CF Trials Register (28 November 2022), reference lists of relevant articles and online trials registries (3 December 2022). SELECTION CRITERIA Randomised controlled trials (RCTs) (parallel design) comparing CFTR correctors to control in pwCF with class II mutations. DATA COLLECTION AND ANALYSIS Two authors independently extracted data, assessed risk of bias and judged evidence certainty (GRADE); we contacted investigators for additional data. MAIN RESULTS We included 34 RCTs (4781 participants), lasting between 1 day and 48 weeks; an extension of two lumacaftor-ivacaftor studies provided additional 96-week safety data (1029 participants). We assessed eight monotherapy RCTs (344 participants) (4PBA, CPX, lumacaftor, cavosonstat and FDL169), 16 dual-therapy RCTs (2627 participants) (lumacaftor-ivacaftor or tezacaftor-ivacaftor) and 11 triple-therapy RCTs (1804 participants) (elexacaftor-tezacaftor-ivacaftor/deutivacaftor; VX-659-tezacaftor-ivacaftor/deutivacaftor; VX-440-tezacaftor-ivacaftor; VX-152-tezacaftor-ivacaftor). Participants in 21 RCTs had the genotype F508del/F508del, in seven RCTs they had F508del/minimal function (MF), in one RCT F508del/gating genotypes, in one RCT either F508del/F508del genotypes or F508del/residual function genotypes, in one RCT either F508del/gating or F508del/residual function genotypes, and in three RCTs either F508del/F508del genotypes or F508del/MF genotypes. Risk of bias judgements varied across different comparisons. Results from 16 RCTs may not be applicable to all pwCF due to age limits (e.g. adults only) or non-standard designs (converting from monotherapy to combination therapy). Monotherapy Investigators reported no deaths or clinically relevant improvements in quality of life (QoL). There was insufficient evidence to determine effects on lung function. No placebo-controlled monotherapy RCT demonstrated differences in mild, moderate or severe adverse effects (AEs); the clinical relevance of these events is difficult to assess due to their variety and few participants (all F508del/F508del). Dual therapy In a tezacaftor-ivacaftor group there was one death (deemed unrelated to the study drug). QoL scores (respiratory domain) favoured both lumacaftor-ivacaftor and tezacaftor-ivacaftor therapy compared to placebo at all time points (moderate-certainty evidence). At six months, relative change in forced expiratory volume in one second (FEV1) % predicted improved with all dual combination therapies compared to placebo (high- to moderate-certainty evidence). More pwCF reported early transient breathlessness with lumacaftor-ivacaftor (odds ratio (OR) 2.05, 99% confidence interval (CI) 1.10 to 3.83; I2 = 0%; 2 studies, 739 participants; high-certainty evidence). Over 120 weeks (initial study period and follow-up), systolic blood pressure rose by 5.1 mmHg and diastolic blood pressure by 4.1 mmHg with twice-daily 400 mg lumacaftor-ivacaftor (80 participants). The tezacaftor-ivacaftor RCTs did not report these adverse effects. Pulmonary exacerbation rates decreased in pwCF receiving additional therapies to ivacaftor compared to placebo (all moderate-certainty evidence): lumacaftor 600 mg (hazard ratio (HR) 0.70, 95% CI 0.57 to 0.87; I2 = 0%; 2 studies, 739 participants); lumacaftor 400 mg (HR 0.61, 95% CI 0.49 to 0.76; I2 = 0%; 2 studies, 740 participants); and tezacaftor (HR 0.64, 95% CI 0.46 to 0.89; 1 study, 506 participants). Triple therapy No study reported any deaths (high-certainty evidence). All other evidence was low- to moderate-certainty. QoL respiratory domain scores probably improved with triple therapy compared to control at six months (six studies). There was probably a greater relative and absolute change in FEV1 % predicted with triple therapy (four studies each across all combinations). The absolute change in FEV1 % predicted was probably greater for F508del/MF participants taking elexacaftor-tezacaftor-ivacaftor compared to placebo (mean difference 14.30, 95% CI 12.76 to 15.84; 1 study, 403 participants; moderate-certainty evidence), with similar results for other drug combinations and genotypes. There was little or no difference in adverse events between triple therapy and control (10 studies). No study reported time to next pulmonary exacerbation, but fewer F508del/F508del participants experienced a pulmonary exacerbation with elexacaftor-tezacaftor-ivacaftor at four weeks (OR 0.17, 99% CI 0.06 to 0.45; 1 study, 175 participants) and 24 weeks (OR 0.29, 95% CI 0.14 to 0.60; 1 study, 405 participants); similar results were seen across other triple therapy and genotype combinations. AUTHORS' CONCLUSIONS There is insufficient evidence of clinically important effects from corrector monotherapy in pwCF with F508del/F508del. Additional data in this review reduced the evidence for efficacy of dual therapy; these agents can no longer be considered as standard therapy. Their use may be appropriate in exceptional circumstances (e.g. if triple therapy is not tolerated or due to age). Both dual therapies (lumacaftor-ivacaftor, tezacaftor-ivacaftor) result in similar small improvements in QoL and respiratory function with lower pulmonary exacerbation rates. While the effect sizes for QoL and FEV1 still favour treatment, they have reduced compared to our previous findings. Lumacaftor-ivacaftor was associated with an increase in early transient shortness of breath and longer-term increases in blood pressure (not observed for tezacaftor-ivacaftor). Tezacaftor-ivacaftor has a better safety profile, although data are lacking in children under 12 years. In this population, lumacaftor-ivacaftor had an important impact on respiratory function with no apparent immediate safety concerns, but this should be balanced against the blood pressure increase and shortness of breath seen in longer-term adult data when considering lumacaftor-ivacaftor. Data from triple therapy trials demonstrate improvements in several key outcomes, including FEV1 and QoL. There is probably little or no difference in adverse events for triple therapy (elexacaftor-tezacaftor-ivacaftor/deutivacaftor; VX-659-tezacaftor-ivacaftor/deutivacaftor; VX-440-tezacaftor-ivacaftor; VX-152-tezacaftor-ivacaftor) in pwCF with one or two F508del variants aged 12 years or older (moderate-certainty evidence). Further RCTs are required in children under 12 years and those with more severe lung disease.
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Affiliation(s)
- Matthew Heneghan
- Department of Women's and Children's Health, University of Liverpool, Liverpool, UK
| | - Kevin W Southern
- Department of Women's and Children's Health, University of Liverpool, Liverpool, UK
| | | | - Ian P Sinha
- Department of Women's and Children's Health, University of Liverpool, Liverpool, UK
| | - Sarah J Nevitt
- Department of Health Data Science, University of Liverpool, Liverpool, UK
- Centre for Reviews and Dissemination, University of York, York, UK
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McLeod C, Wood J, Tong A, Schultz A, Norman R, Smith S, Blyth CC, Webb S, Smyth AR, Snelling TL. The measurement properties of tests and tools used in cystic fibrosis studies: a systematic review. Eur Respir Rev 2021; 30:200354. [PMID: 33980667 PMCID: PMC9489019 DOI: 10.1183/16000617.0354-2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 12/26/2020] [Indexed: 11/05/2022] Open
Abstract
There is no consensus on how best to measure responses to interventions among children and adults with cystic fibrosis (CF). We have systematically reviewed and summarised the characteristics and measurement properties of tests and tools that have been used to capture outcomes in studies among people with CF, including their reliability, validity and responsiveness. This review is intended to guide researchers when selecting tests or tools for measuring treatment effects in CF trials. A consensus set of these tests and tools could improve consistency in how outcomes are captured and thereby facilitate comparisons and synthesis of evidence across studies.
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Affiliation(s)
- Charlie McLeod
- Wesfarmers Centre for Vaccines and Infectious Diseases, Telethon Kids Institute, Nedlands, Australia
- Division of Paediatrics, Faculty of Medicine, University of Western Australia, Nedlands, Australia
- Infectious Diseases Dept, Perth Children's Hospital, Nedlands, Australia
| | - Jamie Wood
- Physiotherapy Dept, Sir Charles Gairdner Hospital, Nedlands, Australia
| | - Allison Tong
- Sydney School of Public Health, The University of Sydney, Sydney, Australia
- Centre for Kidney Research, The Children's Hospital at Westmead, Westmead, Australia
| | - André Schultz
- Wal-yan Respiratory Research Centre, Telethon Kids Institute, University of Western Australia, Nedlands, Australia
- Dept of Respiratory and Sleep Medicine, Perth Children's Hospital, Nedlands, Australia
| | - Richard Norman
- School of Population Health, Curtin University, Bentley, Australia
| | - Sherie Smith
- Evidence Based Child Health Group, University of Nottingham, Queens Medical Centre, Nottingham, UK
| | - Christopher C Blyth
- Wesfarmers Centre for Vaccines and Infectious Diseases, Telethon Kids Institute, Nedlands, Australia
- Division of Paediatrics, Faculty of Medicine, University of Western Australia, Nedlands, Australia
- Infectious Diseases Dept, Perth Children's Hospital, Nedlands, Australia
- Pathwest Laboratory Medicine WA, QEII Medical Centre, Nedlands, Australia
| | - Steve Webb
- St John of God Hospital, Subiaco, Australia
- School of Population Health and Preventive Medicine, Monash University, Melbourne, Australia
| | - Alan R Smyth
- Evidence Based Child Health Group, University of Nottingham, Queens Medical Centre, Nottingham, UK
| | - Thomas L Snelling
- Sydney School of Public Health, The University of Sydney, Sydney, Australia
- Menzies School of Health Research, Royal Darwin Hospital Campus, Tiwi, Australia
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Southern KW, Murphy J, Sinha IP, Nevitt SJ. Corrector therapies (with or without potentiators) for people with cystic fibrosis with class II CFTR gene variants (most commonly F508del). Cochrane Database Syst Rev 2020; 12:CD010966. [PMID: 33331662 PMCID: PMC8094390 DOI: 10.1002/14651858.cd010966.pub3] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND Cystic fibrosis (CF) is a common life-shortening genetic condition caused by a variant in the cystic fibrosis transmembrane conductance regulator (CFTR) protein. A class II CFTR variant F508del (found in up to 90% of people with CF (pwCF)) is the commonest CF-causing variant. The faulty protein is degraded before reaching the cell membrane, where it needs to be to effect transepithelial salt transport. The F508del variant lacks meaningful CFTR function and corrective therapy could benefit many pwCF. Therapies in this review include single correctors and any combination of correctors and potentiators. OBJECTIVES To evaluate the effects of CFTR correctors (with or without potentiators) on clinically important benefits and harms in pwCF of any age with class II CFTR mutations (most commonly F508del). SEARCH METHODS We searched the Cochrane Cystic Fibrosis and Genetic Disorders Cystic Fibrosis Trials Register, reference lists of relevant articles and online trials registries. Most recent search: 14 October 2020. SELECTION CRITERIA Randomised controlled trials (RCTs) (parallel design) comparing CFTR correctors to control in pwCF with class II mutations. DATA COLLECTION AND ANALYSIS Two authors independently extracted data, assessed risk of bias and evidence quality (GRADE); we contacted investigators for additional data. MAIN RESULTS We included 19 RCTs (2959 participants), lasting between 1 day and 24 weeks; an extension of two lumacaftor-ivacaftor studies provided additional 96-week safety data (1029 participants). We assessed eight monotherapy RCTs (344 participants) (4PBA, CPX, lumacaftor, cavosonstat and FDL169), six dual-therapy RCTs (1840 participants) (lumacaftor-ivacaftor or tezacaftor-ivacaftor) and five triple-therapy RCTs (775 participants) (elexacaftor-tezacaftor-ivacaftor or VX-659-tezacaftor-ivacaftor); below we report only the data from elexacaftor-tezacaftor-ivacaftor combination which proceeded to Phase 3 trials. In 14 RCTs participants had F508del/F508del genotypes, in three RCTs F508del/minimal function (MF) genotypes and in two RCTs both genotypes. Risk of bias judgements varied across different comparisons. Results from 11 RCTs may not be applicable to all pwCF due to age limits (e.g. adults only) or non-standard design (converting from monotherapy to combination therapy). Monotherapy Investigators reported no deaths or clinically-relevant improvements in quality of life (QoL). There was insufficient evidence to determine any important effects on lung function. No placebo-controlled monotherapy RCT demonstrated differences in mild, moderate or severe adverse effects (AEs); the clinical relevance of these events is difficult to assess with their variety and small number of participants (all F508del/F508del). Dual therapy Investigators reported no deaths (moderate- to high-quality evidence). QoL scores (respiratory domain) favoured both lumacaftor-ivacaftor and tezacaftor-ivacaftor therapy compared to placebo at all time points. At six months lumacaftor 600 mg or 400 mg (both once daily) plus ivacaftor improved Cystic Fibrosis Questionnaire (CFQ) scores slightly compared with placebo (mean difference (MD) 2.62 points (95% confidence interval (CI) 0.64 to 4.59); 1061 participants; high-quality evidence). A similar effect was observed for twice-daily lumacaftor (200 mg) plus ivacaftor (250 mg), but with low-quality evidence (MD 2.50 points (95% CI 0.10 to 5.10)). The mean increase in CFQ scores with twice-daily tezacaftor (100 mg) and ivacaftor (150 mg) was approximately five points (95% CI 3.20 to 7.00; 504 participants; moderate-quality evidence). At six months, the relative change in forced expiratory volume in one second (FEV1) % predicted improved with combination therapies compared to placebo by: 5.21% with once-daily lumacaftor-ivacaftor (95% CI 3.61% to 6.80%; 504 participants; high-quality evidence); 2.40% with twice-daily lumacaftor-ivacaftor (95% CI 0.40% to 4.40%; 204 participants; low-quality evidence); and 6.80% with tezacaftor-ivacaftor (95% CI 5.30 to 8.30%; 520 participants; moderate-quality evidence). More pwCF reported early transient breathlessness with lumacaftor-ivacaftor, odds ratio 2.05 (99% CI 1.10 to 3.83; 739 participants; high-quality evidence). Over 120 weeks (initial study period and follow-up) systolic blood pressure rose by 5.1 mmHg and diastolic blood pressure by 4.1 mmHg with twice-daily 400 mg lumacaftor-ivacaftor (80 participants; high-quality evidence). The tezacaftor-ivacaftor RCTs did not report these adverse effects. Pulmonary exacerbation rates decreased in pwCF receiving additional therapies to ivacaftor compared to placebo: lumacaftor 600 mg hazard ratio (HR) 0.70 (95% CI 0.57 to 0.87; 739 participants); lumacaftor 400 mg, HR 0.61 (95% CI 0.49 to 0.76; 740 participants); and tezacaftor, HR 0.64 (95% CI, 0.46 to 0.89; 506 participants) (moderate-quality evidence). Triple therapy Three RCTs of elexacaftor to tezacaftor-ivacaftor in pwCF (aged 12 years and older with either one or two F508del variants) reported no deaths (high-quality evidence). All other evidence was graded as moderate quality. In 403 participants with F508del/minimal function (MF) elexacaftor-tezacaftor-ivacaftor improved QoL respiratory scores (MD 20.2 points (95% CI 16.2 to 24.2)) and absolute change in FEV1 (MD 14.3% predicted (95% CI 12.7 to 15.8)) compared to placebo at 24 weeks. At four weeks in 107 F508del/F508del participants, elexacaftor-tezacaftor-ivacaftor improved QoL respiratory scores (17.4 points (95% CI 11.9 to 22.9)) and absolute change in FEV1 (MD 10.0% predicted (95% CI 7.5 to 12.5)) compared to tezacaftor-ivacaftor. There was probably little or no difference in the number or severity of AEs between elexacaftor-tezacaftor-ivacaftor and placebo or control (moderate-quality evidence). In 403 F508del/F508del participants, there was a longer time to protocol-defined pulmonary exacerbation with elexacaftor-tezacaftor-ivacaftor over 24 weeks (moderate-quality evidence). AUTHORS' CONCLUSIONS There is insufficient evidence that corrector monotherapy has clinically important effects in pwCF with F508del/F508del. Both dual therapies (lumacaftor-ivacaftor, tezacaftor-ivacaftor) result in similar improvements in QoL and respiratory function with lower pulmonary exacerbation rates. Lumacaftor-ivacaftor was associated with an increase in early transient shortness of breath and longer-term increases in blood pressure (not observed for tezacaftor-ivacaftor). Tezacaftor-ivacaftor has a better safety profile, although data are lacking in children under 12 years. In this population, lumacaftor-ivacaftor had an important impact on respiratory function with no apparent immediate safety concerns; but this should be balanced against the blood pressure increase and shortness of breath seen in longer-term adult data when considering lumacaftor-ivacaftor. There is high-quality evidence of clinical efficacy with probably little or no difference in AEs for triple (elexacaftor-tezacaftor-ivacaftor) therapy in pwCF with one or two F508del variants aged 12 years or older. Further RCTs are required in children (under 12 years) and those with more severe respiratory function.
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Affiliation(s)
- Kevin W Southern
- Department of Women's and Children's Health, University of Liverpool, Liverpool, UK
| | - Jared Murphy
- Department of Women's and Children's Health, University of Liverpool, Liverpool, UK
| | - Ian P Sinha
- Department of Women's and Children's Health, University of Liverpool, Liverpool, UK
| | - Sarah J Nevitt
- Department of Biostatistics, University of Liverpool, Liverpool, UK
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Pasricha ND, Smith AJ, Levin MH, Schallhorn JM, Verkman AS. Ocular Surface Potential Difference Measured in Human Subjects to Study Ocular Surface Ion Transport. Transl Vis Sci Technol 2020; 9:20. [PMID: 33117611 PMCID: PMC7571274 DOI: 10.1167/tvst.9.11.20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 09/08/2020] [Indexed: 12/14/2022] Open
Abstract
Purpose The epithelium lining the ocular surface, which includes corneal and conjunctival epithelia, expresses the prosecretory chloride channel cystic fibrosis transmembrane conductance regulator (CFTR) and the proabsorptive epithelial sodium channel (ENaC). Here, methodology was established to measure the millivolt (mV) potential differences at the ocular surface, called ocular surface potential difference (OSPD), in human subjects produced by ion transport. Methods OSPD was measured in human subjects in which a fluid-filled measuring electrode contacted a fluid pool created by eversion of the lateral lower eyelid, with a reference electrode placed subcutaneously in the forearm. Through the use of a high-impedance voltmeter, OSPD was measured continuously over 10 to 15 minutes in response to a series of perfusate fluid exchanges. Results Baseline OSPD (± SEM) in six normal human subjects was -21.3 ± 3.6 mV. OSPD depolarized by 1.7 ± 0.6 mV following the addition of the ENaC inhibitor amiloride, hyperpolarized by 6.8 ± 1.5 mV with a zero chloride solution, and further hyperpolarized by 15.9 ± 1.6 mV following CFTR activation by isoproterenol. The isoproterenol-induced hyperpolarization was absent in two cystic fibrosis subjects lacking functional CFTR. OSPD measurement produced minimal epithelial injury. Conclusions Our results establish the feasibility and safety of OSPD measurement in humans and demonstrate robust CFTR activity, albeit minimal ENaC activity, at the ocular surface. OSPD measurement may be broadly applicable to investigate fluid transport mechanisms and test drug candidates to treat ocular surface disorders. Translational Relevance To the best of our knowledge, this is the first measurement of the electrical potential generated by the ocular surface epithelium in human subjects, offering a new approach to study ocular surface function and health.
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Affiliation(s)
- Neel D Pasricha
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA
| | - Alex J Smith
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA.,Departments of Medicine and Physiology, University of California San Francisco, San Francisco, CA, USA
| | - Marc H Levin
- Department of Ophthalmology, Palo Alto Medical Foundation, Palo Alto, CA, USA
| | - Julie M Schallhorn
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA.,Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, USA
| | - Alan S Verkman
- Departments of Medicine and Physiology, University of California San Francisco, San Francisco, CA, USA
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Skilton M, Krishan A, Patel S, Sinha IP, Southern KW. Potentiators (specific therapies for class III and IV mutations) for cystic fibrosis. Cochrane Database Syst Rev 2019; 1:CD009841. [PMID: 30616300 PMCID: PMC6353056 DOI: 10.1002/14651858.cd009841.pub3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
BACKGROUND Cystic fibrosis (CF) is the commonest inherited life-shortening illness in white populations, caused by a mutation in the gene that codes for the cystic fibrosis transmembrane regulator protein (CFTR), which functions as a salt transporter. This mutation mainly affects the airways where excess salt absorption dehydrates the airway lining leading to impaired mucociliary clearance. Consequently, thick, sticky mucus accumulates making the airway prone to chronic infection and progressive inflammation; respiratory failure often ensues. Other complications include malnutrition, diabetes and subfertility.Increased understanding of the condition has allowed pharmaceutical companies to design mutation-specific therapies targeting the underlying molecular defect. CFTR potentiators target mutation classes III and IV and aim to normalise airway surface liquid and mucociliary clearance, which in turn impacts on the chronic infection and inflammation. This is an update of a previously published review. OBJECTIVES To evaluate the effects of CFTR potentiators on clinically important outcomes in children and adults with CF. SEARCH METHODS We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the reference lists of relevant articles, reviews and online clinical trial registries. Last search: 21 November 2018. SELECTION CRITERIA Randomised controlled trials (RCTs) of parallel design comparing CFTR potentiators to placebo in people with CF. A separate review examines trials combining CFTR potentiators with other mutation-specific therapies. DATA COLLECTION AND ANALYSIS The authors independently extracted data, assessed the risk of bias in included trials and used GRADE to assess evidence quality. Trial authors were contacted for additional data. MAIN RESULTS We included five RCTs (447 participants with different mutations) lasting from 28 days to 48 weeks, all assessing the CFTR potentiator ivacaftor. The quality of the evidence was moderate to low, mainly due to risk of bias (incomplete outcome data and selective reporting) and imprecision of results, particularly where few individuals experienced adverse events. Trial design was generally well-documented. All trials were industry-sponsored and supported by other non-pharmaceutical funding bodies.F508del (class II) (140 participants)One 16-week trial reported no deaths, or changes in quality of life (QoL) or lung function (either relative or absolute change in forced expiratory volume in one second (FEV1) (moderate-quality evidence). Pulmonary exacerbations and cough were the most reported adverse events in ivacaftor and placebo groups, but there was no difference between groups (low-quality evidence); there was also no difference between groups in participants interrupting or discontinuing treatment (low-quality evidence). Number of days until the first exacerbation was not reported, but there was no difference between groups in how many participants developed pulmonary exacerbations. There was also no difference in weight. Sweat chloride concentration decreased, mean difference (MD) -2.90 mmol/L (95% confidence interval (CI) -5.60 to -0.20).G551D (class III) (238 participants)The 28-day phase 2 trial (19 participants) and two 48-week phase 3 trials (adult trial (167 adults), paediatric trial (52 children)) reported no deaths. QoL scores (respiratory domain) were higher with ivacaftor in the adult trial at 24 weeks, MD 8.10 (95% CI 4.77 to 11.43) and 48 weeks, MD 8.60 (95% CI 5.27 to 11.93 (moderate-quality evidence). The adult trial reported a higher relative change in FEV1 with ivacaftor at 24 weeks, MD 16.90% (95% CI 13.60 to 20.20) and 48 weeks, MD 16.80% (95% CI 13.50 to 20.10); the paediatric trial reported this at 24 weeks, MD 17.4% (P < 0.0001)) (moderate-quality evidence). These trials demonstrated absolute improvements in FEV1 (% predicted) at 24 weeks, MD 10.80% (95% CI 8.91 to 12.69) and 48 weeks, MD 10.44% (95% CI 8.56 to 12.32). The phase 3 trials reported increased cough, odds ratio (OR) 0.57 (95% CI 0.33 to 1.00) and episodes of decreased pulmonary function, OR 0.29 (95% CI 0.10 to 0.82) in the placebo group; ivacaftor led to increased dizziness in adults, OR 10.55 (95% CI 1.32 to 84.47). There was no difference between groups in participants interrupting or discontinuing treatment (low-quality evidence). Fewer participants taking ivacaftor developed serious pulmonary exacerbations; adults taking ivacaftor developed fewer exacerbations (serious or not), OR 0.54 (95% CI 0.29 to 1.01). A higher proportion of participants were exacerbation-free at 24 weeks with ivacaftor (moderate-quality evidence). Ivacaftor led to a greater absolute change from baseline in FEV1 (% predicted) at 24 weeks, MD 10.80% (95% CI 8.91 to 12.69) and 48 weeks, MD 10.44% (95% CI 8.56 to 12.32); weight also increased at 24 weeks, MD 2.37 kg (95% CI 1.68 to 3.06) and 48 weeks, MD 2.75 kg (95% CI 1.74 to 3.75). Sweat chloride concentration decreased at 24 weeks, MD -48.98 mmol/L (95% CI -52.07 to -45.89) and 48 weeks, MD -49.03 mmol/L (95% CI -52.11 to -45.94).R117H (class IV) (69 participants)One 24-week trial reported no deaths. QoL scores (respiratory domain) were higher with ivacaftor at 24 weeks, MD 8.40 (95% CI 2.17 to 14.63), but no relative changes in lung function were reported (moderate-quality evidence). Pulmonary exacerbations and cough were the most reported adverse events in both groups, but there was no difference between groups; there was no difference between groups in participants interrupting or discontinuing treatment (low-quality evidence). Number of days until the first exacerbation was not reported, but there was no difference between groups in how many participants developed pulmonary exacerbations. No changes in absolute change in FEV1 or weight were reported. Sweat chloride concentration decreased, MD -24.00 mmol/L (CI 95% -24.69 to -23.31). AUTHORS' CONCLUSIONS There is no evidence supporting the use of ivacaftor in people with the F508del mutation. Both G551D phase 3 trials demonstrated a clinically relevant impact of ivacaftor on outcomes at 24 and 48 weeks in adults and children (over six years of age) with CF. The R117H trial demonstrated an improvement in the respiratory QoL score, but no improvement in respiratory function.As new mutation-specific therapies emerge, it is important that trials examine outcomes relevant to people with CF and their families and that adverse events are reported robustly and consistently. Post-market surveillance is essential and ongoing health economic evaluations are required.
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Affiliation(s)
- Mica Skilton
- University of Liverpool, Institute in the Parkc/o Cochrane Cystic Fibrosis and Genetic Disorders Review GroupEaton RoadLiverpoolUKL12 2AP
| | - Ashma Krishan
- University of Liverpool, Alder Hey Children's NHS Foundation TrustDepartment of Women's and Children's HealthEaton RoadLiverpoolMerseysideUKL12 2AP
| | - Sanjay Patel
- Stepping Hill Hopsital, Stockport NHS Foundation TrustPoplar GroveHazel GroveStockportCheshireUKSK2 7JE
| | - Ian P Sinha
- University of LiverpoolDepartment of Women's and Children's HealthAlder Hey Children's Foundation TrustEaton RoadLiverpoolMerseysideUKL12 2AP
| | - Kevin W Southern
- University of LiverpoolDepartment of Women's and Children's HealthAlder Hey Children's Foundation TrustEaton RoadLiverpoolMerseysideUKL12 2AP
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Gramegna A, Aliberti S, Seia M, Porcaro L, Bianchi V, Castellani C, Melotti P, Sorio C, Consalvo E, Franceschi E, Amati F, Contarini M, Gaffuri M, Roncoroni L, Vigone B, Bellofiore A, Del Monaco C, Oriano M, Terranova L, Patria MF, Marchisio P, Assael BM, Blasi F. When and how ruling out cystic fibrosis in adult patients with bronchiectasis. Multidiscip Respir Med 2018; 13:29. [PMID: 30151190 PMCID: PMC6101074 DOI: 10.1186/s40248-018-0142-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Background Bronchiectasis is the final result of different processes and most of the guidelines advocate for a careful evaluation of those etiologies which might be treated or might change patients’ management, including cystic fibrosis (CF). Main body CFTR mutations have been reported with higher frequency in bronchiectasis population. Although ruling out CF is considered as a main step for etiological screening in bronchiectasis, CF testing lacks of a standardized approach both from a research and clinical point of view. In this review a list of most widely used tests in CF is provided. Conclusions Exclusion of CF is imperative for patients with bronchiectasis and CFTR testing should be implemented in usual screening for investigating bronchiectasis etiology. Physicians taking care of bronchiectasis patients should be aware of CFTR testing and its limitations in the adult population. Further studies on CFTR expression in human lung and translational research might elucidate the possible role of CFTR in the pathogenesis of bronchiectasis.
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Affiliation(s)
- Andrea Gramegna
- Department of Pathophysiology and Transplantation, University of Milan, Internal Medicine Department, Respiratory Unit and Cystic Fibrosis Adult Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Stefano Aliberti
- Department of Pathophysiology and Transplantation, University of Milan, Internal Medicine Department, Respiratory Unit and Cystic Fibrosis Adult Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Manuela Seia
- 2Medical Genetics Laboratory, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy
| | - Luigi Porcaro
- 2Medical Genetics Laboratory, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy
| | - Vera Bianchi
- 3UOSD Genetica Medica, Medical Genetics Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy
| | - Carlo Castellani
- 4Centro Fibrosi Cistica, Azienda Ospedaliera Universitaria Integrata, Verona, Italy
| | - Paola Melotti
- 4Centro Fibrosi Cistica, Azienda Ospedaliera Universitaria Integrata, Verona, Italy
| | - Claudio Sorio
- 5Dipartimento di Patologia e Diagnostica, Università di Verona, Verona, Italy
| | - Enza Consalvo
- 2Medical Genetics Laboratory, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy
| | - Elisa Franceschi
- Department of Pathophysiology and Transplantation, University of Milan, Internal Medicine Department, Respiratory Unit and Cystic Fibrosis Adult Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Francesco Amati
- Department of Pathophysiology and Transplantation, University of Milan, Internal Medicine Department, Respiratory Unit and Cystic Fibrosis Adult Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Martina Contarini
- Department of Pathophysiology and Transplantation, University of Milan, Internal Medicine Department, Respiratory Unit and Cystic Fibrosis Adult Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Michele Gaffuri
- 6Department of Otolaryngology and Head and Neck Surgery, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Department of Clinical Sciences and Community Health, University of Milan, 20122 Milan, Italy
| | - Luca Roncoroni
- 6Department of Otolaryngology and Head and Neck Surgery, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Department of Clinical Sciences and Community Health, University of Milan, 20122 Milan, Italy
| | - Barbara Vigone
- 7Scleroderma Unit, Referral Center for Systemic Autoimmune Diseases, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico di Milano, 20122 Milan, Italy
| | - Angela Bellofiore
- Department of Pathophysiology and Transplantation, University of Milan, Internal Medicine Department, Respiratory Unit and Cystic Fibrosis Adult Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Cesare Del Monaco
- Department of Pathophysiology and Transplantation, University of Milan, Internal Medicine Department, Respiratory Unit and Cystic Fibrosis Adult Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Martina Oriano
- Department of Pathophysiology and Transplantation, University of Milan, Internal Medicine Department, Respiratory Unit and Cystic Fibrosis Adult Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milan, Italy.,9Molecular Medicine Department, University of Pavia, Viale Taramelli 3/b, 27100 Pavia, Italy
| | - Leonardo Terranova
- Pediatric Highly Intensive Care Unit, Department of Pathophysiology and Transplantation, Università degli Studi di Milano, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy
| | - Maria Francesca Patria
- Pediatric Highly Intensive Care Unit, Department of Pathophysiology and Transplantation, Università degli Studi di Milano, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy
| | - Paola Marchisio
- Pediatric Highly Intensive Care Unit, Department of Pathophysiology and Transplantation, Università degli Studi di Milano, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy
| | - Baroukh M Assael
- Department of Pathophysiology and Transplantation, University of Milan, Internal Medicine Department, Respiratory Unit and Cystic Fibrosis Adult Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Francesco Blasi
- Department of Pathophysiology and Transplantation, University of Milan, Internal Medicine Department, Respiratory Unit and Cystic Fibrosis Adult Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122 Milan, Italy
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Southern KW, Patel S, Sinha IP, Nevitt SJ. Correctors (specific therapies for class II CFTR mutations) for cystic fibrosis. Cochrane Database Syst Rev 2018; 8:CD010966. [PMID: 30070364 PMCID: PMC6513216 DOI: 10.1002/14651858.cd010966.pub2] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
BACKGROUND Cystic fibrosis (CF) is a common life-shortening condition caused by mutation in the gene that codes for that codes for the cystic fibrosis transmembrane conductance regulator (CFTR) protein, which functions as a salt transporter. F508del, the most common CFTR mutation that causes CF, is found in up to 80% to 90% of people with CF. In people with this mutation, a full length of protein is transcribed, but recognised as misfolded by the cell and degraded before reaching the cell membrane, where it needs to be positioned to effect transepithelial salt transport. This severe mutation is associated with no meaningful CFTR function. A corrective therapy for this mutation could positively impact on an important proportion of the CF population. OBJECTIVES To evaluate the effects of CFTR correctors on clinically important outcomes, both benefits and harms, in children and adults with CF and class II CFTR mutations (most commonly F508del). SEARCH METHODS We searched the Cochrane Cystic Fibrosis and Genetic Disorders Cystic Fibrosis Trials Register. We also searched reference lists of relevant articles and online trials registries. Most recent search: 24 February 2018. SELECTION CRITERIA Randomised controlled trials (RCTs) (parallel design) comparing CFTR correctors to placebo in people with CF with class II mutations. We also included RCTs comparing CFTR correctors combined with CFTR potentiators to placebo. DATA COLLECTION AND ANALYSIS Two authors independently extracted data, assessed risk of bias and quality of the evidence using the GRADE criteria. Study authors were contacted for additional data. MAIN RESULTS We included 13 RCTs (2215 participants), lasting between 1 day and 24 weeks. Additional safety data from an extension study of two lumacaftor-ivacaftor studies were available at 96 weeks (1029 participants). We assessed monotherapy in seven RCTs (317 participants) (4PBA (also known as Buphenyl), CPX, lumacaftor or cavosonstat) and combination therapy in six RCTs (1898 participants) (lumacaftor-ivacaftor or tezacaftor-ivacaftor) compared to placebo. Twelve RCTs recruited individuals homozygous for F508del, one RCT recruited participants with one F508del mutation and a second mutation with residual function.Risk of bias varied in its impact on the confidence we have in our results across different comparisons. Some findings were based on single RCTs that were too small to show important effects. For five RCTs, results may not be applicable to all individuals with CF due to age limits of recruited populations (i.e. adults only, children only) or non-standard design of converting from monotherapy to combination therapy.Monotherapy versus placeboNo deaths were reported and there were no clinically relevant improvements in quality of life in any RCT. There was insufficient evidence available from individual studies to determine the effect of any of the correctors examined on lung function outcomes.No placebo-controlled study of monotherapy demonstrated a difference in mild, moderate or severe adverse effects; however, it is difficult to assess the clinical relevance of these events with the variety of events and the small number of participants.Combination therapy versus placeboNo deaths were reported during any RCT (moderate- to high-quality evidence). The quality of life scores (respiratory domain) favoured combination therapy (both lumacaftor-ivacaftor and tezacaftor-ivacaftor) compared to placebo at all time points. At six months lumacaftor (600 mg once daily or 400 mg once daily) plus ivacaftor improved Cystic Fibrosis Questionnaire (CFQ) scores by a small amount compared with placebo (mean difference (MD) 2.62 points (95% confidence interval (CI) 0.64 to 4.59); 1061 participants; high-quality evidence). A similar effect size was observed for twice-daily lumacaftor (200 mg) plus ivacaftor (250 mg) although the quality of evidence was low (MD 2.50 points (95% CI 0.10 to 5.10)). The mean increase in CFQ scores with twice-daily tezacaftor (100 mg) and ivacaftor (150 mg) was approximately five points (95% CI 3.20 to 7.00; 504 participants; moderate-quality evidence). Lung function measured by relative change in forced expiratory volume in one second (FEV1) % predicted improved with both combination therapies compared to placebo at six months, by 5.21% with once daily lumacaftor-ivacaftor (95% CI 3.61% to 6.80%; 504 participants; high-quality evidence) and by 2.40% with twice-daily lumacaftor-ivacaftor (95% CI 0.40% to 4.40%; 204 participants; low-quality evidence). One study reported an increase in FEV1 with tezacaftor-ivacaftor of 6.80% (95% CI 5.30 to 8.30%; 520 participants; moderate-quality evidence).More participants receiving the lumacaftor-ivacaftor combination reported early transient breathlessness, odds ratio 2.05 (99% CI 1.10 to 3.83; 739 participants; high-quality evidence). In addition, participants allocated to the 400 mg twice-daily dose of lumacaftor-ivacaftor experienced a rise in blood pressure over the 120-week period of the initial studies and the follow-up study of 5.1 mmHg (systolic blood pressure) and 4.1 mmHg (diastolic blood pressure) (80 participants; high-quality evidence). These adverse effects were not reported in the tezacaftor-ivacaftor studies.The rate of pulmonary exacerbations decreased for participants receiving and additional therapies to ivacaftor compared to placebo: lumacaftor 600 mg hazard ratio (HR) 0.70 (95% CI 0.57 to 0.87; 739 participants); lumacaftor 400 mg, HR 0.61 (95% CI 0.49 to 0.76; 740 participants); and tezacaftor, HR 0.64 (95% CI, 0.46 to 0.89; 506 participants) (moderate-quality evidence). AUTHORS' CONCLUSIONS There is insufficient evidence that monotherapy with correctors has clinically important effects in people with CF who have two copies of the F508del mutation.Combination therapies (lumacaftor-ivacaftor and tezacaftor-ivacaftor) each result in similarly small improvements in clinical outcomes in people with CF; specifically improvements quality of life (moderate-quality evidence), in respiratory function (high-quality evidence) and lower pulmonary exacerbation rates (moderate-quality evidence). Lumacaftor-ivacaftor is associated with an increase in early transient shortness of breath and longer-term increases in blood pressure (high-quality evidence). These adverse effects were not observed for tezacaftor-ivacaftor. Tezacaftor-ivacaftor has a better safety profile, although data are not available for children younger than 12 years. In this age group, lumacaftor-ivacaftor had an important impact on respiratory function with no apparent immediate safety concerns, but this should be balanced against the increase in blood pressure and shortness of breath seen in longer-term data in adults when considering this combination for use in young people with CF.
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Affiliation(s)
- Kevin W Southern
- University of LiverpoolDepartment of Women's and Children's HealthAlder Hey Children's NHS Foundation TrustEaton RoadLiverpoolMerseysideUKL12 2AP
| | - Sanjay Patel
- Stepping Hill Hopsital, Stockport NHS Foundation TrustPoplar GroveHazel GroveStockportCheshireUKSK2 7JE
| | - Ian P Sinha
- University of LiverpoolDepartment of Women's and Children's HealthAlder Hey Children's NHS Foundation TrustEaton RoadLiverpoolMerseysideUKL12 2AP
| | - Sarah J Nevitt
- University of LiverpoolDepartment of BiostatisticsBlock F, Waterhouse Building1‐5 Brownlow HillLiverpoolUKL69 3GL
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Lu B, Li L, Schneider M, Hodges CA, Cotton CU, Burgess JD, Kelley TJ. Electrochemical measurement of membrane cholesterol correlates with CFTR function and is HDAC6-dependent. J Cyst Fibros 2018; 18:175-181. [PMID: 29941319 DOI: 10.1016/j.jcf.2018.06.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 06/06/2018] [Accepted: 06/07/2018] [Indexed: 12/18/2022]
Abstract
BACKGROUND Previous studies have demonstrated that CF epithelial cells exhibit increased cholesterol content at the plasma membrane compared to wild type controls as measured by electrochemical methods. Microtubule dysregulation that impacts intracellular transport has also been identified in CF cells and is reversible with histone deacetylase 6 (HDAC6) inhibition, a regulator of tubulin acetylation. The hypothesis of this study is that increased membrane cholesterol content in CF cells is dependent on HDAC6 regulation. METHODS Electrochemical measurement of membrane cholesterol in mouse trachea and in primary human CF bronchial epithelial cells is used to monitor CFTR correction and manipulation of cholesterol processing by HDAC6 inhibition. RESULTS Data demonstrate that induction of Cftr expression in an inducible CF mouse model restores tubulin acetylation levels and normalizes membrane cholesterol content. To test the relationship between tubulin acetylation, membrane cholesterol levels were measured in a CF mouse model depleted of Hdac6 expression (CF/HDA). CF/HDA mouse trachea have WT membrane cholesterol levels while CF mice have approximately two-fold increase in membrane cholesterol compared to WT consistent with previous studies. Pharmacological inhibition of HDAC6 in primary human CF bronchial epithelial cells also reduces membrane cholesterol levels. CONCLUSIONS This study demonstrates that elevated membrane cholesterol in CF epithelium is regulated by HDAC6 function and that the electrochemical measure of membrane cholesterol correlates with both genetic and pharmacological CFTR correction.
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Affiliation(s)
- Binyu Lu
- Department of Chemistry, Case Western Reserve University, United States
| | - Li Li
- Department of Chemistry, Case Western Reserve University, United States
| | - Molly Schneider
- Department of Pediatrics, Case Western Reserve University, United States
| | - Craig A Hodges
- Department of Pediatrics, Case Western Reserve University, United States
| | - Calvin U Cotton
- Department of Pediatrics, Case Western Reserve University, United States
| | - James D Burgess
- Department of Medical, Laboratory, Imaging and Radiologic Sciences, Augusta University, United States
| | - Thomas J Kelley
- Department of Chemistry, Case Western Reserve University, United States; Department of Pediatrics, Case Western Reserve University, United States.
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Abstract
CFTR protein is an ion channel regulated by cAMP-dependent phosphorylation and expressed in many types of epithelial cells. CFTR-mediated chloride and bicarbonate secretion play an important role in the respiratory and gastrointestinal systems. Pharmacological modulators of CFTR represent promising drugs for a variety of diseases. In particular, correctors and potentiators may restore the activity of CFTR in cystic fibrosis patients. Potentiators are also potentially useful to improve mucociliary clearance in patients with chronic obstructive pulmonary disease. On the other hand, CFTR inhibitors may be useful to block fluid and electrolyte loss in secretory diarrhea and slow down the progression of polycystic kidney disease.
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Affiliation(s)
- Olga Zegarra-Moran
- U.O.C. Genetica Medica, Istituto Giannina Gaslini, Via Gerolamo Gaslini 5, 16147, Genoa, Italy
| | - Luis J V Galietta
- U.O.C. Genetica Medica, Istituto Giannina Gaslini, Via Gerolamo Gaslini 5, 16147, Genoa, Italy.
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Vermeulen F, Le Camus C, Davies JC, Bilton D, Milenković D, De Boeck K. Variability of sweat chloride concentration in subjects with cystic fibrosis and G551D mutations. J Cyst Fibros 2016; 16:36-40. [PMID: 26996268 DOI: 10.1016/j.jcf.2016.02.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 01/22/2016] [Accepted: 02/29/2016] [Indexed: 11/25/2022]
Abstract
INTRODUCTION Sweat chloride concentration, a biomarker of CFTR function, is an appropriate outcome parameter in clinical trials aimed at correcting the basic CF defect. Although there is consensus on a cut-off value to diagnose CF, we have only limited information on the within subject variability of sweat chloride over time. Such information would be useful for sample size calculations in clinical trials. Therefore, we retrospectively analyzed repeated sweat chloride values obtained in patients with G551D mutation(s) assigned to placebo in an ivacaftor interventional trial. METHODS In subjects with G551D at least 12years of age, a pilocarpine sweat test using Macroduct collector was taken on both arms at 8 time points over 48weeks. We explored 1062 pilocarpine sweat test values obtained in 78 placebo patients of the VX08-770-102 trial. RESULTS Mean overall sweat chloride value (all patients, all tests, n=1062) was 100.8mmol/L (SD 12.7mmol/L). Using a multilevel mixed model, the between-subject standard deviation (SD) for sweat chloride was 8.9mmol/L (95% CI 7.4-10.6) and within-subject SD was 8.1mmol/L (95% CI 7.5-8.7). Limits of repeatability for repeat measurements were -19.7 to +21.6mmol/L using values from one arm, and -13.3 to 11.8mmol/L using mean of values obtained at 4 test occasions. Sample size calculations showed that the minimal treatment effect on sweat chloride concentration that can be demonstrated for a group of 5 patients is around 15mmol/L, using a cross-over design and combinations of 4 tests for each phase of the trial. CONCLUSION Although the sweat test is considered a robust measure, sweat chloride measurements in patients with CF and a G551D mutation had an inherent biological variability that is higher than commonly considered. Further analyses of placebo group data are crucial to learn more about the natural variability of this outcome parameter.
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Affiliation(s)
- F Vermeulen
- Cystic Fibrosis Reference Centre, University Hospital of Leuven, Leuven, Belgium.
| | - C Le Camus
- Vertex Pharmaceuticals Inc., Cambridge, MA, United States
| | - J C Davies
- Imperial College London, United Kingdom; Paediatric Respiratory Medicine and Department of Cystic Fibrosis , Royal Brompton and Harefield National Health Service Foundation Trust, London, United Kingdom
| | - D Bilton
- Imperial College London, United Kingdom; London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - D Milenković
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - K De Boeck
- Cystic Fibrosis Reference Centre, University Hospital of Leuven, Leuven, Belgium
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Patel S, Sinha IP, Dwan K, Echevarria C, Schechter M, Southern KW. Potentiators (specific therapies for class III and IV mutations) for cystic fibrosis. Cochrane Database Syst Rev 2015:CD009841. [PMID: 25811419 DOI: 10.1002/14651858.cd009841.pub2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
BACKGROUND Cystic fibrosis is the most common inherited life-shortening illness in Caucasians and caused by a mutation in the gene that codes for the cystic fibrosis transmembrane regulator protein (CFTR), which functions as a salt transporter. This mutation most notably affects the airways of people with cystic fibrosis. Excess salt absorption by defective CFTR dehydrates the airway lining and leads to defective mucociliary clearance. Consequent accumulation of thick, sticky mucus makes the airway prone to chronic infection and progressive inflammation; respiratory failure often ensues. Additionally, abnormalities with CFTR lead to systemic complications like malnutrition, diabetes and subfertility.Since the discovery of the causative gene, our understanding of the structure and function of CFTR and the impact of different mutations has increased and allowed pharmaceutical companies to design new mutation-specific therapies targeting the underlying molecular defect. Therapies targeting mutation classes III and IV (CFTR potentiators) aim to normalise airway surface liquid and help re-establish mucociliary clearance, which then has a beneficial impact on the chronic infection and inflammation that characterizes lung disease in people with cystic fibrosis. These therapies may also affect other mutations. OBJECTIVES To evaluate the effects of CFTR potentiators on clinically important outcomes in children and adults with cystic fibrosis. SEARCH METHODS We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the reference lists of relevant articles and reviews. Last search: 05 March 2015.We searched the EU Clinical Trials Register, clinicaltrials.gov (US Clinical Trials Register) and the International Clinical Trials Registry Platform (ICTRP). Last search of clinical trial registries: 06 February 2014. SELECTION CRITERIA Randomised controlled trials of parallel design comparing CFTR potentiators to placebo in people with cystic fibrosis. In a post hoc change we excluded trials combining CFTR potentiators with other mutation-specific therapies. These will be considered in a separate review. DATA COLLECTION AND ANALYSIS The authors independently extracted data and assessed the risk of bias in included trials; they contacted trial authors for additional data. Meta-analyses were undertaken on outcomes at a number of time points. MAIN RESULTS We included four randomised controlled trials (n = 378), lasting from 28 days to 48 weeks, comparing the potentiator ivacaftor to placebo. Trials differed in terms of design and participant eligibility criteria, which limited the meta-analyses. The phase 2 trial (n = 19) and two phase 3 trials (adult trial (n = 167), paediatric trial (n = 52)), recruited participants with the G551D mutation (class III). The fourth trial (n = 140) enrolled participants homozygous for the ΔF508 mutation (class II).Risks of bias in the trials were moderate. Random sequence generation, allocation concealment and blinding of trial personnel were well-documented. Participant blinding was less clear throughout all trials; in three trials, some participant data were excluded from the analysis. Selective outcome reporting was apparent in three trials. All trials were sponsored by industry and supported by other non-pharmaceutical funding bodies.No trial reported any deaths. Significantly higher quality of life scores in the respiratory domain were reported by the adult phase 3 G551D trial at 24 weeks, mean difference 8.10 (95% confidence interval (CI) 4.77 to 11.43) and 48 weeks, mean difference 8.60 (95% CI 5.27 to 11.93); but not by the paediatric phase 3 G551D trial. The adult phase 3 G551D trial reported improvements in relative change from baseline in forced expiratory volume at one second at 24 weeks, mean difference 16.90% (95% CI 13.60 to 20.20) and 48 weeks, mean difference 16.80% (95% CI 13.50 to 20.10); as did the paediatric G551D trial at 24 weeks, mean difference 17.4% (P < 0.0001)). No improvements in quality of life or lung function were reported in the ΔF508 participants.Combined data from both phase 3 G551D trials demonstrated increased reporting of cough, odds ratio 0.57 (95% CI 0.33 to 1.00) and increased episodes of decreased pulmonary function, odds ratio 0.29 (95% CI 0.10 to 0.82) in the placebo group. The adult phase 3 G551D trial demonstrated increased reporting of dizziness amongst the ivacaftor group, OR 10.55 (95% CI 1.32 to 84.47). No trial showed a difference between treatment arms in the number of participants interrupting or discontinuing the trial drug.In the phase 3 G551D trials, fewer participants assigned to ivacaftor developed serious pulmonary exacerbations. When considering all data for exacerbations, participants taking ivacaftor in the adult phase 3 G551D study developed fewer exacerbations, odds ratio 0.54 (95% CI 0.29 to 1.01). In the other G551D studies and in the ΔF508 study, there was no difference between groups in the number of participants who developed pulmonary exacerbations.Combined data from both phase 3 G551D trials demonstrated significant improvements in absolute change from baseline in forced expiratory volume at one second (% predicted) at 24 weeks, mean difference 10.80% (95% CI 8.91 to 12.69) and 48 weeks, mean difference 10.44% (95% CI 8.56 to 12.32); also in weight at 24 weeks, mean difference 2.37 kg (95% CI 1.68 to 3.06) and 48 weeks, mean difference 2.75 kg (95% CI 1.74 to 3.75). No improvements in these outcomes were reported in the ΔF508 participants.Significant reductions in sweat chloride concentration were reported in both G551D and ΔF508 participants: in combined data from both phase 3 G551D trials at 24 weeks, mean difference -48.98 mmol/L (95% CI -52.07 to -45.89) and 48 weeks, mean difference -49.03 mmol/L (95% CI -52.11 to -45.94); and from the ΔF508 trial at 16 weeks, mean difference -2.90 mmol/L (95% CI -5.60 to -0.20). AUTHORS' CONCLUSIONS Both G551D phase 3 trials (n = 219) demonstrated a clinically relevant impact of the potentiator ivacaftor on outcomes at 24 and 48 weeks, providing evidence for the use of this treatment in adults and children (over six years of age) with cystic fibrosis and the G551D mutation (class III). There is no evidence to support the use of ivacaftor in people with the ΔF508 mutation (class II) (n = 140). Trials on ivacaftor in people with different mutations are ongoing.
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Affiliation(s)
- Sanjay Patel
- Department of Women's and Children's Health, University of Liverpool, Alder Hey Children's NHS Foundation Trust, Eaton Road, Liverpool, Merseyside, UK, L12 2AP
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Accurso FJ, Van Goor F, Zha J, Stone AJ, Dong Q, Ordonez CL, Rowe SM, Clancy JP, Konstan MW, Hoch HE, Heltshe SL, Ramsey BW, Campbell PW, Ashlock MA. Sweat chloride as a biomarker of CFTR activity: proof of concept and ivacaftor clinical trial data. J Cyst Fibros 2014; 13:139-47. [PMID: 24660233 DOI: 10.1016/j.jcf.2013.09.007] [Citation(s) in RCA: 107] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND We examined data from a Phase 2 trial {NCT00457821} of ivacaftor, a CFTR potentiator, in cystic fibrosis (CF) patients with aG551D mutation to evaluate standardized approaches to sweat chloride measurement and to explore the use of sweat chloride and nasal potential difference (NPD) to estimate CFTR activity. METHODS Sweat chloride and NPD were secondary endpoints in this placebo-controlled, multicenter trial. Standardization of sweat collection, processing,and analysis was employed for the first time. Sweat chloride and chloride ion transport (NPD) were integrated into a model of CFTR activity. RESULTS Within-patient sweat chloride determinations showed sufficient precision to detect differences between dose-groups and assess ivacaftor treatment effects. Analysis of changes in sweat chloride and NPD demonstrated that patients treated with ivacaftor achieved CFTR activity equivalent to approximately 35%–40% of normal. CONCLUSIONS Sweat chloride is useful in multicenter trials as a biomarker of CFTR activity and to test the effect of CFTR potentiators.
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Electrophysiological evaluation of Cystic Fibrosis Conductance Transmembrane Regulator (CFTR) expression in human monocytes. Biochim Biophys Acta Gen Subj 2014; 1840:3088-95. [DOI: 10.1016/j.bbagen.2014.07.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 06/30/2014] [Accepted: 07/14/2014] [Indexed: 12/31/2022]
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Rowe SM, Reeves G, Hathorne H, Solomon GM, Abbi S, Renard D, Lock R, Zhou P, Danahay H, Clancy JP, Waltz DA. Reduced sodium transport with nasal administration of the prostasin inhibitor camostat in subjects with cystic fibrosis. Chest 2013; 144:200-207. [PMID: 23412700 DOI: 10.1378/chest.12-2431] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Prostasin, a trypsin-like serine protease, is a channel-activating protease and major regulator of epithelial sodium channel-mediated sodium absorption. Its direct inhibition by camostat represents a potential approach to inhibiting sodium transport in cystic fibrosis (CF). METHODS To determine whether a topical formulation of camostat represents an efficacious and tolerable approach to reducing Na+ transport in the CF airway, we conducted a two-part randomized, double-blind, placebo-controlled, crossover, ascending single-dose study to evaluate the pharmacodynamics, safety, and pharmacokinetics of camostat administered through a nasal spray pump in subjects with CF. Nasal potential difference (PD) was measured before and after treatment, and safety and pharmacokinetics were assessed by a standardized approach. RESULTS In part 1, nine subjects were enrolled, and six completed crossover dosing at the maximally tolerated dose. The change in maximal (most polarizing) basal PD 2 h following administration of camostat was +13.1 mV (1.6-mg dose group) compared with -8.6 mV following placebo (P<.005). Intrasubject change in Ringer and amiloride-sensitive PDs exhibited similar and consistent responses. Bayesian analysis in an additional six subjects in part 2 estimated a dose of 18 μg/mL to provide 50% of the maximum effect. There was no significant change in chloride transport or total nasal symptom score, nasal examination rating, and laboratory parameters. CONCLUSIONS This study establishes the proof of concept that a reduction in sodium transport in the human CF airway can be achieved through inhibition of prostasin activity, identifying a potential therapeutic target in the disease. TRIAL REGISTRATION ClinicalTrials.gov; No.: NCT00506792; URL: www.clinicaltrials.gov.
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Affiliation(s)
- Steven M Rowe
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL; Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL; Department of Physiology and Biophysics, University of Alabama at Birmingham, Birmingham, AL; Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL.
| | - Ginger Reeves
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL; Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL
| | - Heather Hathorne
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL; Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL
| | - G Martin Solomon
- Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL
| | - Smita Abbi
- Novartis Institutes for BioMedical Research, East Hanover, NJ
| | - Didier Renard
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Ruth Lock
- Novartis Institutes for BioMedical Research, Horsham, England
| | - Ping Zhou
- Novartis Institutes for BioMedical Research, Horsham, England
| | - Henry Danahay
- Novartis Institutes for BioMedical Research, Horsham, England
| | - John P Clancy
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, and University of Cincinnati, Cincinnati, OH
| | - David A Waltz
- Novartis Institutes for BioMedical Research, Cambridge, MA
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Multicenter intestinal current measurements in rectal biopsies from CF and non-CF subjects to monitor CFTR function. PLoS One 2013; 8:e73905. [PMID: 24040112 PMCID: PMC3769519 DOI: 10.1371/journal.pone.0073905] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 07/23/2013] [Indexed: 11/30/2022] Open
Abstract
Intestinal current measurements (ICM) from rectal biopsies are a sensitive means to detect cystic fibrosis transmembrane conductance regulator (CFTR) function, but have not been optimized for multicenter use. We piloted multicenter standard operating procedures (SOPs) to detect CFTR activity by ICM and examined key questions for use in clinical trials. SOPs for ICM using human rectal biopsies were developed across three centers and used to characterize ion transport from non-CF and CF subjects (two severe CFTR mutations). All data were centrally evaluated by a blinded interpreter. SOPs were then used across four centers to examine the effect of cold storage on CFTR currents and compare CFTR currents in biopsies from one subject studied simultaneously either at two sites (24 hours post-biopsy) or when biopsies were obtained by either forceps or suction. Rectal biopsies from 44 non-CF and 17 CF subjects were analyzed. Mean differences (µA/cm2; 95% confidence intervals) between CF and non-CF were forskolin/IBMX=102.6(128.0 to 81.1), carbachol=96.3(118.7 to 73.9), forskolin/IBMX+carbachol=200.9(243.1 to 158.6), and bumetanide=-44.6 (-33.7 to -55.6) (P<0.005, CF vs non-CF for all parameters). Receiver Operating Characteristic curves indicated that each parameter discriminated CF from non-CF subjects (area under the curve of 0.94-0.98). CFTR dependent currents following 18-24 hours of cold storage for forskolin/IBMX, carbachol, and forskolin/IBMX+carbachol stimulation (n=17 non-CF subjects) were 44%, 47.5%, and 47.3%, respectively of those in fresh biopsies. CFTR-dependent currents from biopsies studied after cold storage at two sites simultaneously demonstrated moderate correlation (n=14 non-CF subjects, Pearson correlation coefficients 0.389, 0.484, and 0.533). Similar CFTR dependent currents were detected from fresh biopsies obtained by either forceps or suction (within-subject comparisons, n=22 biopsies from three non-CF subjects). Multicenter ICM is a feasible CFTR outcome measure that discriminates CF from non-CF ion transport, offers unique advantages over other CFTR bioassays, and warrants further development as a potential CFTR biomarker.
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16
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Naehrlich L, Ballmann M, Davies J, Derichs N, Gonska T, Hjelte L, van Konigsbruggen-Rietschel S, Leal T, Melotti P, Middleton P, Tümmler B, Vermeulen F, Wilschanski M. Nasal potential difference measurements in diagnosis of cystic fibrosis: an international survey. J Cyst Fibros 2013; 13:24-8. [PMID: 24022019 DOI: 10.1016/j.jcf.2013.08.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2013] [Revised: 08/02/2013] [Accepted: 08/13/2013] [Indexed: 12/21/2022]
Abstract
BACKGROUND The role of nasal potential difference (NPD) measurement as a diagnostic test for cystic fibrosis (CF) is a subject of global controversy because of the lack of validation studies, clear reference values, and standardized protocols for diagnostic NPD. METHODS To determine diagnostic NPD frequency, protocols, interpretation, and rater agreement, we surveyed the 18 NPD centres of the European Cystic Fibrosis Society Diagnostic Network Working Group. RESULTS Fifteen centres reported performing 373 diagnostic NPDs in 2012. Most use the CFF-TDN-SOP (67%) and the chloride-free + isoproterenol response of the side with the largest response (47%) as diagnostic criteria and use centre-specific reference ranges. Rater agreement for five NPD tracings - in general - was good, but poor in tracings with different responses between the two nostrils. CONCLUSIONS NPD is frequently used as a diagnostic and research tool for CF. Performance is highly standardized, centre-specific reference ranges are established, and rater agreement - in general - is good. Centre-independent diagnostic criteria and reference ranges must be defined by multicentre validation studies to improve standardized interpretation for diagnostic use.
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Affiliation(s)
- Lutz Naehrlich
- Department of Pediatrics, Justus-Liebig-University Giessen, Giessen, Germany.
| | - Manfred Ballmann
- Ruhr University Paediatric Clinic at St Josef Hospital, Bochum, Germany
| | - Jane Davies
- Paediatric Respiratory Medicine, Royal Brompton and Harefield NHS Foundation Trust, United Kingdom; Respiratory Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, United Kingdom; Department of Gene Therapy, Imperial College London, United Kingdom
| | - Nico Derichs
- CFTR Biomarker Centre and Translational CF Research Group Christiane Herzog Cystic Fibrosis Centre, Paediatric Pulmonology and Immunology, Charité Universitätsmedizin Berlin, Berlin, Germany
| | | | - Lena Hjelte
- Stockholm Cystic Fibrosis Center, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | | | - Teresinha Leal
- Louvain Centre for Toxicology and Applied Pharmacology (LTAP), Université catholique de Louvain, Brussels, Belgium
| | - Paola Melotti
- Cystic Fibrosis Center, Azienda Ospedaliera Universitaria Integrata di Verona, Verona, Italy
| | - Peter Middleton
- Cystic Fibrosis Unit, Ludwig Engel Centre for Respiratory Research, Westmead Millennium Institute, University of Sydney at Westmead, Westmead, NSW, Australia
| | - Burkhard Tümmler
- Klinik für Pädiatrische Pneumologie, Allergologie und Neonatologie, OE 6710, Medizinische Hochschule Hannover, Hannover, Germany
| | - Francois Vermeulen
- Cystic Fibrosis Reference Centre, University Hospital Gasthuisberg, Catholic University of Leuven, Leuven, Belgium
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17
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Rowe SM, Liu B, Hill A, Hathorne H, Cohen M, Beamer JR, Accurso FJ, Dong Q, Ordoñez CL, Stone AJ, Olson ER, Clancy JP. Optimizing nasal potential difference analysis for CFTR modulator development: assessment of ivacaftor in CF subjects with the G551D-CFTR mutation. PLoS One 2013; 8:e66955. [PMID: 23922647 PMCID: PMC3724869 DOI: 10.1371/journal.pone.0066955] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 05/13/2013] [Indexed: 11/18/2022] Open
Abstract
Nasal potential difference (NPD) is used as a biomarker of the cystic fibrosis transmembrane conductance regulator (CFTR) and epithelial sodium channel (ENaC) activity. We evaluated methods to detect changes in chloride and sodium transport by NPD based on a secondary analysis of a Phase II CFTR-modulator study. Thirty-nine subjects with CF who also had the G551D-CFTR mutation were randomized to receive ivacaftor (Kalydeco™; also known as VX-770) in four doses or placebo twice daily for at least 14 days. All data were analyzed by a single investigator who was blinded to treatment assignment. We compared three analysis methods to determine the best approach to quantify changes in chloride and sodium transport: (1) the average of both nostrils; (2) the most-polarized nostril at each visit; and (3) the most-polarized nostril at screening carried forward. Parameters of ion transport included the PD change with zero chloride plus isoproterenol (CFTR activity), the basal PD, Ringer's PD, and change in PD with amiloride (measurements of ENaC activity), and the delta NPD (measuring CFTR and ENaC activity). The average and most-polarized nostril at each visit were most sensitive to changes in chloride and sodium transport, whereas the most-polarized nostril at screening carried forward was less discriminatory. Based on our findings, NPD studies should assess both nostrils rather than a single nostril. We also found that changes in CFTR activity were more readily detected than changes in ENaC activity, and that rigorous standardization was associated with relatively good within-subject reproducibility in placebo-treated subjects (±2.8 mV). Therefore, we have confirmed an assay of reasonable reproducibility for detecting chloride-transport improvements in response to CFTR modulation.
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Affiliation(s)
- Steven M. Rowe
- University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Bo Liu
- University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Aubrey Hill
- University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Heather Hathorne
- University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Morty Cohen
- Seattle Children's Hospital, Seattle, Washington, United States of America
| | - John R. Beamer
- Seattle Children's Hospital, Seattle, Washington, United States of America
| | - Frank J. Accurso
- University of Colorado Denver, Aurora, Colorado, United States of America
| | - Qunming Dong
- Vertex Pharmaceuticals Incorporated, Cambridge, Massachusetts, United States of America
| | - Claudia L. Ordoñez
- Vertex Pharmaceuticals Incorporated, Cambridge, Massachusetts, United States of America
| | - Anne J. Stone
- Vertex Pharmaceuticals Incorporated, Cambridge, Massachusetts, United States of America
| | - Eric R. Olson
- Vertex Pharmaceuticals Incorporated, Cambridge, Massachusetts, United States of America
| | - John P. Clancy
- Cincinnati Children's Hospital Medical Center and the University of Cincinnati, Cincinnati, Ohio, United States of America
- * E-mail:
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18
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Schiffhauer ES, Vij N, Kovbasnjuk O, Kang PW, Walker D, Lee S, Zeitlin PL. Dual activation of CFTR and CLCN2 by lubiprostone in murine nasal epithelia. Am J Physiol Lung Cell Mol Physiol 2013; 304:L324-31. [PMID: 23316067 DOI: 10.1152/ajplung.00277.2012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Multiple sodium and chloride channels on the apical surface of nasal epithelial cells contribute to periciliary fluid homeostasis, a function that is disrupted in patients with cystic fibrosis (CF). Among these channels is the chloride channel CLCN2, which has been studied as a potential alternative chloride efflux pathway in the absence of CFTR. The object of the present study was to use the nasal potential difference test (NPD) to quantify CLCN2 function in an epithelial-directed TetOn CLCN2 transgenic mouse model (TGN-K18rtTA-hCLCN2) by using the putative CLCN2 pharmacological agonist lubiprostone and peptide inhibitor GaTx2. Lubiprostone significantly increased chloride transport in the CLCN2-overexpressing mice following activation of the transgene by doxycycline. This response to lubiprostone was significantly inhibited by GaTx2 after CLCN2 activation in TGN-CLCN2 mice. Cftr(-/-) and Clc2(-/-) mice showed hyperpolarization indicative of chloride efflux in response to lubiprostone, which was fully inhibited by GaTx2 and CFTR inhibitor 172 + GlyH-101, respectively. Our study reveals lubiprostone as a pharmacological activator of both CFTR and CLCN2. Overexpression and activation of CLCN2 leads to improved mouse NPD readings, suggesting it is available as an alternative pathway for epithelial chloride secretion in murine airways. The utilization of CLCN2 as an alternative chloride efflux channel could provide clinical benefit to patients with CF, especially if the pharmacological activator is administered as an aerosol.
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Affiliation(s)
- Eric S Schiffhauer
- Department of Pediatrics, The Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
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19
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Misdiagnosis of cystic fibrosis — Experience from Germany. J Cyst Fibros 2013; 12:68-73. [DOI: 10.1016/j.jcf.2012.06.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2012] [Revised: 06/17/2012] [Accepted: 06/18/2012] [Indexed: 11/20/2022]
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20
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Rowe SM, Borowitz DS, Burns JL, Clancy JP, Donaldson SH, Retsch-Bogart G, Sagel SD, Ramsey BW. Progress in cystic fibrosis and the CF Therapeutics Development Network. Thorax 2012; 67:882-90. [PMID: 22960984 PMCID: PMC3787701 DOI: 10.1136/thoraxjnl-2012-202550] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cystic fibrosis (CF), the most common life-shortening genetic disorder in Caucasians, affects approximately 70 000 individuals worldwide. In 1998, the Cystic Fibrosis Foundation (CFF) launched the CF Therapeutics Development Network (CF-TDN) as a central element of its Therapeutics Development Programme. Designed to accelerate the clinical evaluation of new therapies needed to fulfil the CFF mission to control and cure CF, the CF-TDN has conducted 75 clinical trials since its inception, and has contributed to studies as varied as initial safety and proof of concept trials to pivotal programmes required for regulatory approval. This review highlights recent and significant research efforts of the CF-TDN, including a summary of contributions to studies involving CF transmembrane conductance regulator (CFTR) modulators, airway surface liquid hydrators and mucus modifiers, anti-infectives, anti-inflammatories, and nutritional therapies. Efforts to advance CF biomarkers, necessary to accelerate the therapeutic goals of the network, are also summarised.
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Affiliation(s)
- Steven M Rowe
- Department of Medicine, University of Alabama at Birmingham, 1819 University Boulevard (MCLM 768), Birmingham, AL 35294, USA.
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21
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Roomans GM. Pharmacological Approaches to Correcting the Ion Transport Defect in Cystic Fibrosis. ACTA ACUST UNITED AC 2012; 2:413-31. [PMID: 14719993 DOI: 10.1007/bf03256668] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Cystic fibrosis (CF) is a lethal genetic disease caused by a mutation in a membrane protein, the cystic fibrosis transmembrane conductance regulator (CFTR), which mainly (but not exclusively) functions as a chloride channel. The main clinical symptoms are chronic obstructive lung disease, which is responsible for most of the morbidity and mortality associated with CF, and pancreatic insufficiency. About 1000 mutations of the gene coding for CFTR are currently known; the most common of these, present in the great majority of the patients (Delta508) results in the deletion of a phenylalanine at position 508. In this mutation, the aberrant CFTR is not transported to the membrane but degraded in the ubiquitin-proteasome pathway. The aim of this review is to give an overview of the pharmacologic strategies currently used in attempts to overcome the ion transport defect in CF. One strategy to develop pharmacologic treatment for CF is to inhibit the breakdown of DeltaF508-CFTR by interfering with the chaperones involved in the folding of CFTR. At least in in vitro systems, this can be accomplished by sodium phenylbutyrate, or S-nitrosoglutathione (GSNO), and also by genistein or benzo[c]quinolizinium compounds. It is also possible to stimulate CFTR or its mutated forms, when present in the plasma membrane, using xanthines, genistein, and various other compounds, such as benzamidizoles and benzoxazoles, benzo[c]quinolizinium compounds or phenantrolines. Experimental results are not always unambiguous, and adverse effects have been incompletely tested. Some clinical tests have been done on sodium phenyl butyrate, GSNO and genistein, mostly in respect to other diseases, and the results demonstrate that these drugs are reasonably well tolerated. Their efficiency in the treatment of CF has not yet been demonstrated, however. An alternative strategy is to compensate for the defective chloride transport by CFTR by stimulation of other chloride channels. This can be done via purinergic receptors. A phase I study using a stable uridine triphosphate analog has recently been completed. A second alternative strategy is to attempt to maintain hydration of the airway mucus by inhibiting Na(+) uptake by the epithelial Na(+) channel using amiloride or stable analogs of amiloride. Clinical tests so far have been inconclusive. A number of other suggestions are currently being explored. The minority of patients with CF who have a stop mutation may benefit from treatment with gentamicin. The difficulties in finding a pharmacologic treatment for CF may be due to the fact that CFTR has additional functions besides chloride transport, and interfering with CFTR biosynthesis or activation implies interference with central cellular processes, which may have undesirable adverse effects.
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Affiliation(s)
- Godfried M Roomans
- Department of Medical Cell Biology, University of Uppsala, Uppsala, Sweden.
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22
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Defective CFTR expression and function are detectable in blood monocytes: development of a new blood test for cystic fibrosis. PLoS One 2011; 6:e22212. [PMID: 21811577 PMCID: PMC3141019 DOI: 10.1371/journal.pone.0022212] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2010] [Accepted: 06/21/2011] [Indexed: 12/22/2022] Open
Abstract
Background Evaluation of cystic fibrosis transmembrane conductance regulator (CFTR) functional activity to assess new therapies and define diagnosis of cystic fibrosis (CF) is cumbersome. It is known that leukocytes express detectable levels of CFTR but the molecule has not been characterized in these cells. In this study we aim at setting up and validating a blood test to evaluate CFTR expression and function in leukocytes. Description Western blot, PCR, immunofluorescence and cell membrane depolarization analysis by single-cell fluorescence imaging, using the potential-sensitive DiSBAC2(3) probe were utilized. Expression of PKA phosphorylated, cell membrane-localized CFTR was detected in non-CF monocytes, being undetectable or present in truncated form in monocytes derived from CF patients presenting with nonsense mutations. CFTR agonist administration induced membrane depolarization in monocytes isolated from non-CF donors (31 subjects) and, to a lesser extent, obligate CFTR heterozygous carriers (HTZ: 15 subjects), but it failed in monocytes from CF patients (44 subjects). We propose an index, which values in CF patients are significantly (p<0.001) lower than in the other two groups. Nasal Potential Difference, measured in selected subjects had concordant results with monocytes assay (Kappa statistic 0.93, 95%CI: 0.80–1.00). Results and Significance CFTR is detectable and is functional in human monocytes. We also showed that CFTR-associated activity can be evaluated in 5 ml of peripheral blood and devise an index potentially applicable for diagnostic purposes and both basic and translational research: from drug development to evaluation of functional outcomes in clinical trials.
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23
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Vermeulen F, Proesmans M, Feyaerts N, De Boeck K. Nasal potential measurements on the nasal floor and under the inferior turbinate: does it matter? Pediatr Pulmonol 2011; 46:145-52. [PMID: 20865746 DOI: 10.1002/ppul.21333] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2010] [Revised: 06/28/2010] [Accepted: 07/02/2010] [Indexed: 11/10/2022]
Abstract
AIM Measurement of nasal potential difference (NPD) is increasingly used as diagnostic test for cystic fibrosis (CF) and for in vivo evaluation of treatments aimed at correcting the defective function of the cystic fibrosis transmembrane regulator (CFTR) protein. Several methods are used to measure NPD. This study explores the influence of the site of measurement and compares NPD results obtained on the nasal floor and under the inferior turbinate. METHODS NPD was measured in 34 CF, 26 heterozygote, and 61 control subjects. In every subject, measurements were taken simultaneously under the inferior turbinate in one nostril, and on the nasal floor in the other nostril. Criteria for interpretable tracings were predefined. Repeat measurements were done in 57 persons. RESULTS More interpretable tracings were obtained under the turbinate (120/124) than on the nasal floor (109/124), P = 0.015. Within each subject group, mean values obtained were similar for maximal basal potential, response to amiloride, and total chloride response. Both techniques discriminate well between CF and controls. Repeatability was similar with both methods: mean differences between two measurements approximated zero for most values. Also after correction for different number of interpretable tracings, simulation of sample size calculation for use in CFTR corrective trials was slightly in favor of measurements obtained on the nasal floor. CONCLUSION NPD measurements under the inferior turbinate and on the nasal floor have similar discriminative power for diagnostic use. Measurements under the turbinate result in a slightly higher proportion of interpretable tracings but sample size calculation slightly favors the nasal floor method.
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Affiliation(s)
- François Vermeulen
- Cystic Fibrosis Reference Centre, University Hospital Gasthuisberg, Catholic University of Leuven, Leuven, Belgium.
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24
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Rowe SM, Clancy JP, Wilschanski M. Nasal potential difference measurements to assess CFTR ion channel activity. Methods Mol Biol 2011; 741:69-86. [PMID: 21594779 DOI: 10.1007/978-1-61779-117-8_6] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The Nasal potential difference measurement is used to measure the voltage across the nasal epithelium, which results from transepithelial ion transport and reflects in part CFTR function. The electrophysiologic abnormality in cystic fibrosis was first described 30 years ago and correlates with features of the CF phenotype. NPD measurement is an important in vivo research and diagnostic tool, and is used to assess the efficacy of new treatments such as gene therapy and ion transport modulators. This chapter will elaborate on the electrophysiological principles behind the test, the equipment required, the methods, and the analysis of the data.
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Affiliation(s)
- Steven M Rowe
- Department of Medicine, University of Alabama, Birmingham, AL 35294-0006, USA.
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Neuberger T, Burton B, Clark H, Van Goor F. Use of primary cultures of human bronchial epithelial cells isolated from cystic fibrosis patients for the pre-clinical testing of CFTR modulators. Methods Mol Biol 2011; 741:39-54. [PMID: 21594777 DOI: 10.1007/978-1-61779-117-8_4] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The use of human bronchial epithelial (HBE) cell cultures derived from the bronchi of CF patients offers the opportunity to study the effects of CFTR correctors and potentiators on CFTR function and epithelial cell biology in the native pathological environment. Cultured HBE cells derived from CF patients exhibit many of the morphological and functional characteristics believed to be associated with CF airway disease in vivo, including abnormal ion and fluid transport leading to dehydration of the airway surface and the loss of cilia beating. In addition, they can be generated in sufficient quantities to support routine lab testing of compound potency and efficacy and retain reproducible levels of CFTR function over time. Here we describe the development and validation of the CF HBE pharmacology model and its use to characterize, optimize, and select clinical candidates. It is expected that the pre-clinical testing of CFTR potentiators and correctors using epithelial cell cultures derived from CF patients will help to increase their likelihood of clinical efficacy.
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26
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Mac Sweeney R, Fischer H, McAuley DF. Nasal potential difference to detect Na+ channel dysfunction in acute lung injury. Am J Physiol Lung Cell Mol Physiol 2010; 300:L305-18. [PMID: 21112943 DOI: 10.1152/ajplung.00223.2010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Pulmonary fluid clearance is regulated by the active transport of Na(+) and Cl(-) through respiratory epithelial ion channels. Ion channel dysfunction contributes to the pathogenesis of various pulmonary fluid disorders including high-altitude pulmonary edema (HAPE) and neonatal respiratory distress syndrome (RDS). Nasal potential difference (NPD) measurement allows an in vivo investigation of the functionality of these channels. This technique has been used for the diagnosis of cystic fibrosis, the archetypal respiratory ion channel disorder, for over a quarter of a century. NPD measurements in HAPE and RDS suggest constitutive and acquired dysfunction of respiratory epithelial Na(+) channels. Acute lung injury (ALI) is characterized by pulmonary edema due to alveolar epithelial-interstitial-endothelial injury. NPD measurement may enable identification of critically ill ALI patients with a susceptible phenotype of dysfunctional respiratory Na(+) channels and allow targeted therapy toward Na(+) channel function.
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Affiliation(s)
- R Mac Sweeney
- Respiratory Medicine Research Programme, Centre for Infection and Immunity, Queen’s University, Belfast, Northern Ireland
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27
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Middleton PG, House HH. Measurement of airway ion transport assists the diagnosis of cystic fibrosis. Pediatr Pulmonol 2010; 45:789-95. [PMID: 20597077 DOI: 10.1002/ppul.21253] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The nasal potential difference (PD) demonstrates the increased Na absorption and decreased Cl secretion typically found in cystic fibrosis (CF). It provides useful information for diagnostic purposes and measures the effect of new treatments on the ion transport defects found in CF. This study summarizes the nasal PD results in the respiratory tract of different groups of subjects, examines the responses in squamous epithelia and evaluates new ways to consider nasal PD results.Nasal PD was tested using the standard protocol of baseline, amiloride, low chloride, and isoproterenol solutions in 40 healthy non-CF volunteers, 46 CF subjects, and 78 subjects referred for investigation of possible CF. Nasal PD was also measured in the squamous epithelium at the anterior nares in six non-CF subjects.Baseline PD was elevated in the CF (47.5 (1.7) mV) compared with non-CF subjects: (14.0 (0.8) mV, P < 0.00001). Combined [Cl + Isop] responses were smaller in the CF (-0.1 (0.4) mV) compared with the non-CF subjects (26.2 (1.2) mV, P < 0.00001). In the diagnostic cohort 58 were given a non-CF diagnosis, 16 had CF confirmed, but 4 remained indeterminate. Separate consideration of Na and Cl transport was easily portrayed through X-Y plots. Finally, the nasal PD responses of squamous epithelium showed high baseline values, but little response to amiloride and low chloride solutions.The nasal PD provides useful information in the diagnostic algorithm of CF, and in the delineation of the two ion transport defects characteristically found in the respiratory epithelium. Avoidance of the squamous epithelium remains an important consideration for those performing and interpreting nasal PD responses.
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Affiliation(s)
- Peter G Middleton
- Cystic Fibrosis Unit, Ludwig Engel Centre for Respiratory Research, Westmead Millennium Institute, University of Sydney at Westmead, Westmead, NSW, Australia.
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Sermet-Gaudelus I, Boeck KD, Casimir GJ, Vermeulen F, Leal T, Mogenet A, Roussel D, Fritsch J, Hanssens L, Hirawat S, Miller NL, Constantine S, Reha A, Ajayi T, Elfring GL, Miller LL. Ataluren (PTC124) induces cystic fibrosis transmembrane conductance regulator protein expression and activity in children with nonsense mutation cystic fibrosis. Am J Respir Crit Care Med 2010; 182:1262-72. [PMID: 20622033 DOI: 10.1164/rccm.201001-0137oc] [Citation(s) in RCA: 179] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Nonsense (premature stop codon) mutations in mRNA for the cystic fibrosis transmembrane conductance regulator (CFTR) cause cystic fibrosis (CF) in approximately 10% of patients. Ataluren (PTC124) is an oral drug that permits ribosomes to readthrough premature stop codons in mRNA to produce functional protein. OBJECTIVES To evaluate ataluren activity, safety, and pharmacokinetics in children with nonsense mutation CF. METHODS Patients were assessed in two 28-day cycles, comprising 14 days on and 14 days off ataluren. Patients took ataluren three times per day (morning, midday, and evening) with randomization to the order of receiving a lower dose (4, 4, and 8 mg/kg) and a higher dose (10, 10, and 20 mg/kg) in the two cycles. MEASUREMENTS AND MAIN RESULTS The study enrolled 30 patients (16 male and 14 female, ages 6 through 18 yr) with a nonsense mutation in at least one allele of the CFTR gene, a classical CF phenotype, and abnormal baseline nasal epithelial chloride transport. Ataluren induced a nasal chloride transport response (at least a -5-mV improvement) or hyperpolarization (value more electrically negative than -5 mV) in 50% and 47% of patients, respectively, with more hyperpolarizations at the higher dose. Improvements were seen in seven of nine nonsense mutation genotypes represented. Ataluren significantly increased the proportion of nasal epithelial cells expressing apical full-length CFTR protein. Adverse events and laboratory abnormalities were infrequent and usually mild. Ataluren pharmacokinetics were similar to those in adults. CONCLUSIONS In children with nonsense mutation CF, ataluren can induce functional CFTR production and is well tolerated.
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Solomon GM, Konstan MW, Wilschanski M, Billings J, Sermet-Gaudelus I, Accurso F, Vermeulen F, Levin E, Hathorne H, Reeves G, Sabbatini G, Hill A, Mayer-Hamblett N, Ashlock M, Clancy JP, Rowe SM. An international randomized multicenter comparison of nasal potential difference techniques. Chest 2010; 138:919-28. [PMID: 20472865 DOI: 10.1378/chest.10-0179] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND The transepithelial nasal potential difference (NPD) is used to assess cystic fibrosis transmembrane conductance regulator (CFTR) activity. Unreliability, excessive artifacts, and lack of standardization of current testing systems can compromise its use as a diagnostic test and outcome measure for clinical trials. METHODS To determine whether a nonperfusing (agar gel) nasal catheter for NPD measurement is more reliable and less susceptible to artifacts than a continuously perfusing nasal catheter, we performed a multicenter, randomized, crossover trial comparing a standardized NPD protocol using an agar nasal catheter with the same protocol using a continuously perfusing catheter. The data capture technique was identical in both protocols. A total of 26 normal adult subjects underwent NPD testing at six different centers. RESULTS Artifact frequency was reduced by 75% (P < .001), and duration was less pronounced using the agar catheter. The measurement of sodium conductance was similar between the two catheter methods, but the agar catheter demonstrated significantly greater CFTR-dependent hyperpolarization, because Δ zero Cl- + isoproterenol measurements were significantly more hyperpolarized with the agar catheter (224.2 ± 12.9 mV with agar vs 18.2 ± 9.1 mV with perfusion, P < .05). CONCLUSIONS The agar nasal catheter approach demonstrates superior reliability compared with the perfusion nasal catheter method for measurement of NPD. This nonperfusion catheter method should be considered for adoption as a standardized protocol to monitor CFTR activity in clinical trials.
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Affiliation(s)
- George M Solomon
- University of Alabama at Birmingham, Birmingham, AL 35294-0006, USA
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Spinelli E, Seia M, Melotti P, Marchina E, Padoan R. CFTR mutation in an Arab patient: Clinical and functional features of 875+1G→A/875+1G→A genotype. J Cyst Fibros 2009; 8:282-4. [DOI: 10.1016/j.jcf.2009.05.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Revised: 04/22/2009] [Accepted: 05/06/2009] [Indexed: 11/29/2022]
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31
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Moran O, Zegarra-Moran O. On the measurement of the functional properties of the CFTR. J Cyst Fibros 2008; 7:483-94. [PMID: 18818127 DOI: 10.1016/j.jcf.2008.05.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 04/01/2008] [Accepted: 05/14/2008] [Indexed: 10/21/2022]
Abstract
A number of methods are currently employed to assess the functional properties of CFTR channels and their response to pharmacological potentiators, correction of the defective CFTR trafficking, and vectorial introduction of new proteins. Here we review the most common methods used to assess CFTR channel function. The suitability of each technique to various experimental conditions is discussed.
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Affiliation(s)
- Oscar Moran
- Istituto di Biofisica, CNR, 16149 Genova, Italy.
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Leal T, Fajac I, Wallace HL, Lebecque P, Lebacq J, Hubert D, Dall'Ava J, Dusser D, Ganesan AP, Knoop C, Cumps J, Wallemacq P, Southern KW. Airway ion transport impacts on disease presentation and severity in cystic fibrosis. Clin Biochem 2008; 41:764-72. [PMID: 18424267 DOI: 10.1016/j.clinbiochem.2008.03.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2007] [Revised: 03/15/2008] [Accepted: 03/23/2008] [Indexed: 11/19/2022]
Abstract
OBJECTIVES Abnormal airway ion transport is a feature of cystic fibrosis. The aim of this study was to investigate whether distinct components of ion transport are associated with the clinical expression and severity of the disease. DESIGN AND METHODS Univariate and multivariate analyses were used to study interaction effects between nasal potential difference parameters and clinical status, recorded at stable conditions, in 75 F508del homozygous young adults. RESULTS All patients demonstrated increased sodium and reduced chloride conductances. Less sodium transport abnormalities were related to better respiratory function and nutrition. Presentation with digestive symptoms at diagnosis was associated with lower chloride conductance. With an accuracy of 85% good nutritional status was linked to more preserved lung function, increasing age and more preserved chloride conductance. CONCLUSIONS Ion transport abnormalities have distinct clinical outcomes. Sodium conductance relates to respiratory function and nutrition; chloride conductance to nutrition and presentation with digestive symptoms at diagnosis.
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Affiliation(s)
- Teresinha Leal
- Clinical Chemistry, Université Catholique de Louvain, Brussels, Belgium
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Goss CH, Mayer-Hamblett N, Williams J, Ramsey BW. The Cystic Fibrosis Foundation Therapeutics Development Network: A National Effort by the Cystic Fibrosis Foundation to Build a Clinical Trials Network. CHILDRENS HEALTH CARE 2008. [DOI: 10.1080/02739610701766859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Rowe SM, Accurso F, Clancy JP. Detection of cystic fibrosis transmembrane conductance regulator activity in early-phase clinical trials. Ann Am Thorac Soc 2007; 4:387-98. [PMID: 17652506 PMCID: PMC2647604 DOI: 10.1513/pats.200703-043br] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Advances in our understanding of cystic fibrosis pathogenesis have led to strategies directed toward treatment of underlying causes of the disease rather than treatments of disease-related symptoms. To expedite evaluation of these emerging therapies, early-phase clinical trials require extension of in vivo cystic fibrosis transmembrane conductance regulator (CFTR)-detecting assays to multicenter trial formats, including nasal potential difference and sweat chloride measurements. Both of these techniques can be used to fulfill diagnostic criteria for the disease, and can discriminate various levels of CFTR function. Full realization of these assays in multicenter clinical trials requires identification of sources of nonbiological intra- and intersite variability, and careful attention to study design and statistical analysis of study-generated data. In this review, we discuss several issues important to the performance of these assays, including efforts to identify and address aspects that can contribute to inconsistent and/or potentially erroneous results. Adjunctive means of detecting CFTR including mRNA expression, immunocytochemical localization, and other methods are also discussed. Recommendations are presented to advance our understanding of these biomarkers and to improve their capacity to predict cystic fibrosis outcomes.
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Affiliation(s)
- Steven M Rowe
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294-0006, USA.
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35
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Mayer-Hamblett N, Ramsey BW, Kronmal RA. Advancing outcome measures for the new era of drug development in cystic fibrosis. PROCEEDINGS OF THE AMERICAN THORACIC SOCIETY 2007; 4:370-7. [PMID: 17652504 PMCID: PMC2647602 DOI: 10.1513/pats.200703-040br] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2007] [Accepted: 04/27/2007] [Indexed: 11/20/2022]
Abstract
The growing pipeline of candidate drugs for cystic fibrosis (CF) is challenging clinical trial research. There has been a shift from evaluating drugs aimed at treating the secondary manifestations of CF to evaluating drugs targeted toward the primary prevention of chronic lung disease. As CF is an orphan disease, there is a fundamental need to assess new therapies efficiently and accurately by mechanisms that best use the number of available patients. This need can be addressed with the continued advancement and refinement of CF outcome measures. We begin by presenting an overview of the outcome measures currently used in CF clinical studies, defined and categorized in terms of one of the three main classes of endpoints: clinical efficacy measures, surrogate endpoints, and biomarkers. To move forward efficiently, clinical research in CF is dependent on the development of new outcomes able to capture biologic and clinical response to novel therapeutic approaches. We conclude with a discussion of the criteria by which all new outcome measures should be evaluated. A systematic, rigorous approach to outcome measure development is needed to provide the tools necessary for evaluating new therapies and moving drugs out of the pipeline and into the CF clinic.
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Clancy JP, Rowe SM, Bebok Z, Aitken ML, Gibson R, Zeitlin P, Berclaz P, Moss R, Knowles MR, Oster RA, Mayer-Hamblett N, Ramsey B. No detectable improvements in cystic fibrosis transmembrane conductance regulator by nasal aminoglycosides in patients with cystic fibrosis with stop mutations. Am J Respir Cell Mol Biol 2007; 37:57-66. [PMID: 17347447 PMCID: PMC1899350 DOI: 10.1165/rcmb.2006-0173oc] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Cystic fibrosis (CF) is an autosomal recessive disorder caused by many types of genetic defects, including premature stop codons. Gentamicin can suppress stop mutations in CF transmembrane conductance regulator (CFTR) in vitro and in vivo, leading to improvements in CFTR-dependent ion transport and protein localization to the apical surface of respiratory epithelial cells. The primary objective of this study was to test whether nasally administered gentamicin or tobramycin could suppress premature stop mutations in CFTR, resulting in full-length, functional protein. A secondary objective was to obtain data to aid in the design of multicenter trials using the nasal potential difference as a study endpoint. A multicenter study was conducted in two cohorts of patients with CF, those heterozygous for stop mutations in the CFTR gene and those without nonsense mutations, to investigate the effects of both gentamicin and tobramycin administered over a 28-d period on sequential nasal potential difference and airway cell immunofluorescence endpoints. Eleven patients with CF with stop mutations were enrolled in a randomized, double-blinded, crossover fashion to receive each drug, while 18 subjects with CF without stop mutations were randomized 1:1 in a parallel fashion to receive one drug. After demonstration of drug delivery, neither aminoglycoside produced detectable changes in nasal ion transport or CFTR localization in brushed cells from either study group. These results with first-generation suppressive agents suggest the need for improved drug delivery methods and/or more potent suppressors of nonsense mutations to confer CFTR correction in subjects with CF heterozygous for nonsense mutations. The study provides valuable information on parameters of the nasal potential difference measurements for use in future multicenter clinical trials.
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Affiliation(s)
- John P Clancy
- Department of Pediatrics, University of Alabama at Birmingham, 1600 7th Avenue South, Birmingham, AL 35233, USA.
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Abstract
Cystic fibrosis is usually diagnosed based on suspicion arising from a typical clinical picture and must be confirmed by either a finding of high chloride concentrations in sweat tests on 2 separate days or detection of 2 gene mutations. The nasal potential difference (NPD) test has been proposed to provide evidence of abnormal function of the cystic fibrosis transmembrane conductance regulator (CFTR), a receptor that forms a chloride ion channel. The test is especially useful for patients who have normal chloride concentrations in sweat tests and in whom 2 gene mutations related to cystic fibrosis have not been detected. The NPD test requires 2 electrodes connected to a voltmeter (a Tholy-Medicap device). One is placed on the nasal mucosa of the inferior turbinate and the other is placed subcutaneously on the forearm. A reading less than -40 mV is considered abnormal, as values under that cut point are never found in healthy individuals. Two abnormal NPD findings on separate days are required for a diagnosis of CFTR dysfunction. False negatives arise when the integrity of the epithelium is altered. After application of amiloride, NPD decreases more markedly in cystic fibrosis patients than in healthy individuals and applying isoproterenol or fenoterol after amiloride provokes no response in patients with the genetic defect that prevents chloride ion channel activation.
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Affiliation(s)
- C Domingo-Ribas
- Servicio de Neumología, Corporació Parc Taulí-Universidad Autónoma de Barcelona, Sabadell, Barcelona, Spain.
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38
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Lee H, Koehler DR, Pang CY, Levine RH, Ng P, Palmer DJ, Quinton PM, Hu J. Gene delivery to human sweat glands: a model for cystic fibrosis gene therapy. Gene Ther 2006; 12:1752-60. [PMID: 16034452 DOI: 10.1038/sj.gt.3302587] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Gene therapy vectors are mostly studied in cultured cells, rodents, and sometimes in non-human primates, but it is useful to test them in human tissue prior to clinical trials. In this study, we investigated the possibility of using human sweat glands as a model for testing cystic fibrosis (CF) gene therapy vectors. Human sweat glands are relatively easy to obtain from skin biopsy, and can be tested for CFTR function. Using patients' sweat glands could provide a safe model to study the efficacy of CF gene therapy. As the first step to explore using sweat glands as a model for CF gene therapy, we examined various ex vivo gene delivery methods for a helper-dependent adenovirus (HD-Ad) vector. Gene delivery to sweat glands in skin organ culture was studied by topical application, intradermal injection or submerged culture. We found that transduction efficiency can be enhanced by pretreating isolated sweat glands with dispase, which suggests that the basement membrane is a critical barrier to gene delivery by adenoviral vectors. Using this approach, we showed that Cftr could be efficiently delivered to and expressed by the epithelial cells of sweat glands with our helper-dependent adenoviral vector containing cytokeratin 18 regulatory elements. Based on this study we propose that sweat glands might be used as an alternative model to study CF gene therapy in humans.
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Affiliation(s)
- H Lee
- Research Institute, The Hospital for Sick Children, Toronto, Canada
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39
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Domingo-Ribas C, Bosque-García M. Prueba de la diferencia de potencial nasal para el diagnóstico de la fibrosis quística. Arch Bronconeumol 2006. [DOI: 10.1157/13083278] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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40
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Zhang LN, Karp P, Gerard CJ, Pastor E, Laux D, Munson K, Yan Z, Liu X, Godwin S, Thomas CP, Zabner J, Shi H, Caldwell CW, Peluso R, Carter B, Engelhardt JF. Dual Therapeutic Utility of Proteasome Modulating Agents for Pharmaco-gene Therapy of the Cystic Fibrosis Airway. Mol Ther 2004; 10:990-1002. [PMID: 15564131 DOI: 10.1016/j.ymthe.2004.08.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2004] [Accepted: 08/17/2004] [Indexed: 11/19/2022] Open
Abstract
Pharmacologic- and gene-based therapies have historically been developed as two independent therapeutic platforms for cystic fibrosis (CF) lung disease. Inhibition of the dysregulated epithelial Na channel (ENaC) is one pharmacologic approach to enhance airway clearance in CF. We investigated pharmacologic approaches to enhance CFTR gene delivery with recombinant adeno-associated virus (rAAV) and identified compounds that significantly improved viral transduction while simultaneously inhibiting ENaC activity through an unrelated mechanism. Treatment of human CF airway epithelia with proteasome modulating agents (LLnL and doxorubicin) at the time of rAAV2 or rAAV2/5 infection dramatically enhanced CFTR gene delivery and correction of CFTR-mediated short-circuit currents. Surprisingly, these agents also facilitated long-term (15-day) functional inhibition of ENaC currents independent of CFTR vector administration. Inhibition of ENaC activity was predominantly attributed to a doxorubicin-dependent decrease in gamma-ENaC subunit mRNA expression and an increase in gamma-ENaC promoter methylation. This is the first report to describe the identification of compounds with dual therapeutic action that are able to enhance the efficacy of CFTR gene therapy to the airway while simultaneously ameliorating primary aspects of CF disease pathophysiology. The identification of such compounds mark a new area for drug development, not only for CF, but also for other gene therapy disease targets.
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Affiliation(s)
- Liang N Zhang
- Department of Anatomy and Cell Biology, University of Iowa College of Medicine, Iowa City, IA 52242, USA
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41
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Davis PB, Schluchter MD, Konstan MW. Relation of sweat chloride concentration to severity of lung disease in cystic fibrosis. Pediatr Pulmonol 2004; 38:204-9. [PMID: 15274098 DOI: 10.1002/ppul.20054] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In cystic fibrosis (CF), sweat chloride concentration has been proposed as an index of CFTR function for testing systemic drugs designed to activate mutant CFTR. This suggestion arises from the assumption that greater residual CFTR function should lead to a lower sweat chloride concentration, as well as protection against severe lung disease. This logic gives rise to the hypothesis that the lower the sweat chloride concentration, the less severe the lung disease. In order to test this hypothesis, we studied 230 patients homozygous for the DeltaF508 allele, and 34 patients with at least one allele associated with pancreatic sufficiency, born since January 1, 1955, who have pulmonary function data and sweat chloride concentrations recorded in our CF center database, and no culture positive for B. cepacia. We calculated a severity index for pulmonary disease, using an approach which takes into account all available pulmonary function data as well as the patient's current age and survival status. Patients with alleles associated with pancreatic sufficiency had significantly better survival (P = 0.0083), lower sweat chloride concentration (81.4 +/- 23.8 vs. 103.2 +/- 14.2 mEq/l, P < 0.0001), slower rate of decline of FEV(1) % predicted (-0.75 +/- 0.34 vs. -2.34 +/- 0.17% predicted per year), and a better severity index than patients homozygous for the DeltaF508 allele (median 73rd percentile vs. median 55th percentile, P = 0.0004). However, the sweat chloride concentration did not correlate with the severity index, either in the population as a whole, or in the population of patients with alleles associated with pancreatic sufficiency, who are thought to have some residual CFTR function. These data suggest that, by itself, sweat chloride concentration does not necessarily predict a milder pulmonary course in patients with cystic fibrosis.
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Affiliation(s)
- Pamela B Davis
- Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, USA.
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42
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Schüler D, Sermet-Gaudelus I, Wilschanski M, Ballmann M, Dechaux M, Edelman A, Hug M, Leal T, Lebacq J, Lebecque P, Lenoir G, Stanke F, Wallemacq P, Tümmler B, Knowles MR. Basic protocol for transepithelial nasal potential difference measurements. J Cyst Fibros 2004; 3 Suppl 2:151-5. [PMID: 15463949 DOI: 10.1016/j.jcf.2004.05.032] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Transepithelial nasal potential difference (NPD) measurements assess ion conductance in the upper respiratory epithelium. NPD is useful in assisting in the diagnosis of classical and atypical cystic fibrosis (CF) and of cystic fibrosis transmembrane regulator (CFTR)-related disorders, as well as for monitoring the effect of pharmacological agents and gene transfer approaches to correct the abnormalities of ion transport in CF. The article summarizes the objectives and the principle of NPD measurements, describes a hands-on protocol of the procedure and provides quality control measures, practical hints and troubleshooting.
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Affiliation(s)
- Daniel Schüler
- CF Center, Children Hospital of Justus Liebig University, 35385 Giessen, Germany
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Salinas DB, Pedemonte N, Muanprasat C, Finkbeiner WF, Nielson DW, Verkman AS. CFTR involvement in nasal potential differences in mice and pigs studied using a thiazolidinone CFTR inhibitor. Am J Physiol Lung Cell Mol Physiol 2004; 287:L936-43. [PMID: 15246976 DOI: 10.1152/ajplung.00354.2003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nasal potential difference (PD) measurements have been used to demonstrate defective CFTR function in cystic fibrosis (CF) and to evaluate potential CF therapies. We used the selective thiazolidinone CFTR inhibitor CFTR(inh)-172 to define the involvement of CFTR in nasal PD changes in mice and pigs. In normal mice infused intranasally with a physiological saline solution containing amiloride, nasal PD was -4.7 +/- 0.7 mV, hyperpolarizing by 15 +/- 1 mV after a low-Cl- solution, and a further 3.9 +/- 0.5 mV after forskolin. CFTR(inh)-172 produced 1.1 +/- 0.9- and 4.3 +/- 0.7-mV depolarizations when added after low Cl- and forskolin, respectively. Systemically administered CFTR(inh)-172 reduced the forskolin-induced hyperpolarization from 4.7 +/- 0.4 to 0.9 +/- 0.1 mV but did not reduce the low Cl(-)-induced hyperpolarization. Nasal PD was -12 +/- 1 mV in CF mice after amiloride, changing by <0.5 mV after low Cl- or forskolin. In pigs, nasal PD was -14 +/- 3 mV after amiloride, hyperpolarizing by 13 +/- 2 mV after low Cl- and a further 9 +/- 1 mV after forskolin. CFTR(inh)-172 and glibenclamide did not affect nasal PD in pigs. Our results suggest that cAMP-dependent nasal PDs in mice primarily involve CFTR-mediated Cl- conductance, whereas cAMP-independent PDs are produced by a different, but CFTR-dependent, Cl- channel. In pigs, CFTR may not be responsible for Cl- channel-dependent nasal PDs. These results have important implications for interpreting nasal PDs in terms of CFTR function in animal models of CFTR activation and inhibition.
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Affiliation(s)
- Danieli B Salinas
- Department of Medicine and Physiology, Cardiovascular Research Institute, University of California, San Francisco, California 94143, USA
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44
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Standaert TA, Boitano L, Emerson J, Milgram LJH, Konstan MW, Hunter J, Berclaz PY, Brass L, Zeitlin PL, Hammond K, Davies Z, Foy C, Noone PG, Knowles MR. Standardized procedure for measurement of nasal potential difference: an outcome measure in multicenter cystic fibrosis clinical trials. Pediatr Pulmonol 2004; 37:385-92. [PMID: 15095320 DOI: 10.1002/ppul.10448] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Patients with cystic fibrosis (CF) can be discriminated from healthy subjects by measurement of the nasal potential difference, which has become a useful outcome measure for therapies directed toward correcting defective electrolyte transport in CF. A standard operating procedure was developed by a CF Foundation clinical trials network, to be followed by all sites performing collaborative studies. Key variables in the measurement included type of voltmeter, exploring probe, reference electrodes, and solutions used to assess both sodium transport and chloride conductance. Eight sites submitted data on 3-8 normal and 4-5 CF subjects. Baseline voltage, an index of sodium transport, was -18.2 +/- 8.3 mV (mean +/- SD) for normals, and -45.3 +/- 11.4 mV for CF patients. There was no CFTR-mediated chloride secretion in CF subjects, as evidenced by the lack of response to perfusion with zero chloride + beta agonist solutions (+3.2 +/- 3.5 mV) vs. that in normals (-23.7 +/- 10.2 mV). The standardized nasal potential difference measurement minimizes variability between operators and study sites. Valid and consistent results can be attained with trained operators and attention to technical details. These data demonstrate the procedure to be sufficient for multicenter studies in the CF Foundation network.
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45
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Boyle MP, Diener-West M, Milgram L, Knowles M, Foy C, Zeitlin P, Standaert T. A multicenter study of the effect of solution temperature on nasal potential difference measurements. Chest 2003; 124:482-9. [PMID: 12907532 DOI: 10.1378/chest.124.2.482] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND Nasal potential difference (PD) measurement quantifies the abnormal sodium and chloride transport that is characteristic of cystic fibrosis (CF) and has gained acceptance as both a diagnostic tool and outcome measure for new CF therapies. Because small changes in nasal PD-measured chloride transport are often an important component in evaluating new CF therapies, techniques to maximize sensitivity and reproducibility are essential. STUDY OBJECTIVE To determine if administration of warmed nasal PD solutions (37 degrees C), instead of room temperature solutions (22 degrees C), results in significant increase in nasal PD-measured transepithelial chloride transport. DESIGN Multicenter, prospective, cross-over trial of repeated measurements of nasal PD at 22 degrees C and 37 degrees C. RESULTS Thirty-two healthy volunteers completed the study (four centers, each with 8 subjects). For 22 degrees C vs 37 degrees C, baseline (+/- SD) nasal PD (- 19.3 +/- 6.9 millivolts [mV] vs - 18.8 +/- 7.7 mV, p = 0.76), amiloride-sensitive PD (Delta PD, 10.4 +/- 5.6 mV vs 11.0 +/- 6.1 mV, p = 0.60), and low chloride response (Delta PD, - 10.0 +/- 8.0 mV vs - 8.0 +/- 7.1 mV, p = 0.13) were not statistically significantly affected by warming of solutions. Warming solutions to 37 degrees C dramatically increased the chloride transport response to isoproterenol (Delta PD, - 6.9 +/- 6.4 mV vs - 13.3 +/- 8.8 mV, p < 0.01) and the combined total response to low chloride and isoproterenol (Delta PD, - 16.9 +/- 9.5 mV vs - 21.3 +/- 11.9 mV, p = 0.01). The average increases observed with warming in isoproterenol and combined total responses were - 6.4 mV (95% confidence interval [CI], - 8.5 to - 4.3) and - 4.4 mV (95% CI, - 7.6 to - 1.1), respectively. CONCLUSIONS Performing nasal PD studies with solutions at 37 degrees C instead of 22 degrees C increases the observed total chloride response by approximately 25% and the isoproterenol-dependent chloride response by approximately 95%. The Cystic Fibrosis Foundation Therapeutics Development Network now recommends warming of solutions as a standard procedure for nasal PD protocols. Utilization of warmed solutions will standardize nasal PD techniques across centers and potentially increase the ability to identify therapies that result in small incremental improvements in CF transmembrane conductance regulator function.
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Affiliation(s)
- Michael P Boyle
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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Leal T, Lebacq J, Lebecque P, Cumps J, Wallemacq P. Modified method to measure nasal potential difference. Clin Chem Lab Med 2003; 41:61-7. [PMID: 12636051 DOI: 10.1515/cclm.2003.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Nasal potential difference (NPD) measurements have been proposed to assess defective ion transport in cystic fibrosis (CF). Implementing it routinely is, however, difficult. Therefore, a modified method based on nasal instillation in supine position at reduced flow rate was tested to evaluate its ability to discriminate CF from non-CF subjects. Classical and modified methods were compared in nine healthy subjects and there were no statistical differences. Following the new method, 97 tests were performed on 74 subjects divided in three cohorts: 21 CF patients and two control groups consisting of 19 patients with other pulmonary diseases and 34 healthy subjects. Twenty five children were enrolled in this study. Maximal NPD in CF patients (-44.9 +/- 2.5 mV) was significantly different from that obtained in control groups (-18.1 +/- 1.6 and -17.2 +/- 1.1 mV). Depolarization after amiloride also discriminated CF patients (25.9 +/- 1.4 mV) from control groups (10.5 +/- 0.9 and 8.1 +/- 0.7 mV). Marked repolarization following isoprenaline plus amiloride in low chloride solution was seen in control groups (-15.7 +/- 1.1 and -15.3 +/- 1.1 mV). We conclude that the modified method represents a simplified and equally effective approach to discriminate CF patients from non-CF subjects. Moreover, this method presents practical advantages for the patients related to hygiene and convenience, favoring its application in small children.
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Affiliation(s)
- Teresinha Leal
- Department of Clinical Chemistry, Université Catholique de Louvain, St Luc University Hospital, Brussels, Belgium
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Kidd JF, Bear CE. Epithelial cell chloride channel activity correlates with improved airway function in cystic fibrosis patients with the major mutant: Delta F508. Pediatr Res 2002; 52:625-7. [PMID: 12409505 DOI: 10.1203/00006450-200211000-00004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Jacqueline F Kidd
- Programme in Structural Biology and Biochemistry, Research Institute, Hospital for Sick Children and Department of Biochemistry, Faculty of Medicine, Toronto, Canada M5G 1X8
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LeGrys VA. Response to "Use of nasal potential differences and sweat chloride as outcome measures in multicenter clinical trials in subjects with cystic fibrosis". Pediatr Pulmonol 2002; 34:155; author reply 156. [PMID: 12112786 DOI: 10.1002/ppul.10147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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McCarty NA, Standaert TA, Teresi M, Tuthill C, Launspach J, Kelley TJ, Milgram LJH, Hilliard KA, Regelmann WE, Weatherly MR, Aitken ML, Konstan MW, Ahrens RC. A phase I randomized, multicenter trial of CPX in adult subjects with mild cystic fibrosis. Pediatr Pulmonol 2002; 33:90-8. [PMID: 11802244 DOI: 10.1002/ppul.10041] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
CPX (8-cyclopentyl-1,3-dipropylxanthine) is a novel compound currently under development as a potential treatment for cystic fibrosis (CF). The drug has been shown to increase chloride efflux and CFTR trafficking in vitro in CF airway cells. This phase I multicenter, single-dose, placebo-controlled trial was performed at four institutions. Thirty-seven subjects homozygous for the Delta F(508) allele were studied in an escalating dose protocol of seven single-dose cohorts (1, 3, 10, 30, 100, 300, and 1,000 mg) to evaluate the safety, pharmacokinetics, and efficacy of CPX. Efficacy was determined using nasal transepithelial potential difference and sweat chloride measurements prior to dosing and at 1, 2, and 4 hr postdose. The incidence of adverse events in the treatment group was similar to that with placebo, indicating safety of the single doses studied. One serious adverse event (an acute pulmonary exacerbation) occurred 13 days after dosing, and was not considered related to the study drug. The maximal plasma CPX concentration and total amount of CPX absorbed appeared to be linearly related to dose, but was highly variable throughout the dose range studied, suggesting inconsistent absorption. There was no apparent effect of single-dose administration on either nasal transepithelial potential difference or sweat chloride measurements. The positive safety and pharmacokinetic findings of this study support continued development of CPX as a potential therapeutic for CF.
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Affiliation(s)
- Nael A McCarty
- Department of Physiology, Emory University, Atlanta, Georgia, USA.
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