{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,29]],"date-time":"2026-09-29T15:40:29Z","timestamp":1790696429266,"version":"4.1.0"},"reference-count":30,"publisher":"Portland Press Ltd.","issue":"15","content-domain":{"domain":["portlandpress.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2017,8,1]]},"abstract":"<jats:p>G551D, a mutation of the cystic fibrosis transmembrane conductance regulator (CFTR) gene, results in impaired chloride channel function in cystic fibrosis (CF) with multiple end-organ manifestations. The effect of ivacaftor, a CFTR-potentiator, on exercise capacity in CF is unknown. Twenty G551D-CF patients were recruited to a single-centre, double-blind, placebo-controlled, 28-day crossover study of ivacaftor. Variables measured included percentage change from baseline (%\u0394) of VO2max (maximal oxygen consumption, primary outcome) during cardiopulmonary exercise testing (CPET), relevant other CPET physiological variables, lung function, body mass index (BMI), sweat chloride and disease-specific health related quality of life (QOL) measures (CFQ-R and Alfred Wellness (AWEscore)). %\u0394VO2max was unchanged compared with placebo as was %\u0394minute ventilation. However, %\u0394exercise time (mean 7.3, CI 0.5\u201314,1, P=0.0222) significantly increased as did %\u0394FEV1 (11.7%, range 5.3\u201318.1, P&amp;lt;0\u00b7005) and %\u0394BMI (1.2%, range 0.1\u20132.3, P=0\u00b70393) whereas sweat chloride decreased (mean \u221243.4; range \u221255.5\u201318.1 mmol\u00b7l\u22121, P&amp;lt;0\u00b7005). Total and activity based domains in both CFQ-R and AWEscore also increased. A positive treatment effect on spirometry, BMI (increased), SCT (decreased) and total and activity based CF-specific QOL measures was expected. However, the lack of discernible improvement in VO2max and VE despite other positive changes including spirometric lung function and exercise time with a 28-day ivacaftor intervention suggests that ventilatory parameters are not the sole driver of change in exercise capacity in this study cohort. Investigation over a more prolonged period may delineate the potential interdependencies of the observed discordances over time. Trial registration number: ClinicalTrials.gov-NCT01937325.<\/jats:p>","DOI":"10.1042\/cs20170995","type":"journal-article","created":{"date-parts":[[2017,6,14]],"date-time":"2017-06-14T00:10:38Z","timestamp":1497399038000},"page":"2037-2045","update-policy":"https:\/\/doi.org\/10.1042\/crossmark_policy","source":"Crossref","is-referenced-by-count":53,"title":["Improvement in exercise duration, lung function and well-being in G551D-cystic fibrosis patients: a double-blind, placebo-controlled, randomized, cross-over study with ivacaftor treatment"],"prefix":"10.1042","volume":"131","author":[{"given":"Deirdre","family":"Edgeworth","sequence":"first","affiliation":[{"name":"Cystic Fibrosis Service, The Alfred, Melbourne, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dominic","family":"Keating","sequence":"additional","affiliation":[{"name":"Cystic Fibrosis Service, The Alfred, Melbourne, Australia"},{"name":"Department of Medicine, Monash University, Melbourne, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Matthew","family":"Ellis","sequence":"additional","affiliation":[{"name":"Cystic Fibrosis Service, The Alfred, Melbourne, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Brenda","family":"Button","sequence":"additional","affiliation":[{"name":"Cystic Fibrosis Service, The Alfred, Melbourne, Australia"},{"name":"Department of Physiotherapy, The Alfred, Melbourne, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Elyssa","family":"Williams","sequence":"additional","affiliation":[{"name":"Cystic Fibrosis Service, The Alfred, Melbourne, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Denise","family":"Clark","sequence":"additional","affiliation":[{"name":"Cystic Fibrosis Service, The Alfred, Melbourne, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Audrey","family":"Tierney","sequence":"additional","affiliation":[{"name":"Cystic Fibrosis Service, The Alfred, Melbourne, Australia"},{"name":"Department of Nutrition and Dietetics, The Alfred, Melbourne, Australia"},{"name":"Department of Dietetics and Human Nutrition, La Trobe University, Melbourne, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stephane","family":"Heritier","sequence":"additional","affiliation":[{"name":"Cystic Fibrosis Service, The Alfred, Melbourne, Australia"},{"name":"School of Public Health and Preventative Medicine, Monash University, Melbourne, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tom","family":"Kotsimbos","sequence":"additional","affiliation":[{"name":"Cystic Fibrosis Service, The Alfred, Melbourne, Australia"},{"name":"Department of Medicine, Monash University, Melbourne, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"John","family":"Wilson","sequence":"additional","affiliation":[{"name":"Cystic Fibrosis Service, The Alfred, Melbourne, Australia"},{"name":"Department of Medicine, Monash University, Melbourne, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"288","published-online":{"date-parts":[[2017,7,17]]},"reference":[{"key":"2021113011050678500_B1","doi-asserted-by":"crossref","first-page":"166","DOI":"10.1159\/000132791","article-title":"Report of the committee on the genetic constitution of chromosomes 7 and 8","volume":"51","author":"Tsui","year":"1989","journal-title":"Cytogenet. 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