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Drug & research development » Clinical trials » NCT00457821

Safety Study of Ivacaftor in Subjects With Cystic Fibrosis

Official title: A Phase 2a, Randomized, Double-Blind, Placebo-Controlled Study of VX-770 to Evaluate Safety, Pharmacokinetics, and Biomarkers of CFTR Activity in Cystic Fibrosis (CF) Subjects With Genotype G551D

Clinical Trials gov number: NCT00457821

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Purpose: To evaluate the safety and tolerability of ivacaftor in CF patients aged ≥18 years who have a G551D mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene.

Phase: 2

Type: Interventional, randomized, double-blind, crossover

Study sponsor: Vertex Pharmaceuticals Incorporated; Cystic Fibrosis Foundation Therapeutics

  • Weigh ≥40kg
  • Confirmed diagnosis CF and G551D mutation in ≥1 allele
  • Forced expiratory volume in 1 second (FEV1) of at least 40% of predicted normal for age, gender, and height
  • Willing to remain on stable medication regimen for the duration of study participation
  • No significant clinical laboratory abnormalities, not pregnant, and willing to use at least 2 highly effective birth control methods during Part 1 and 1 highly effective birth control method during Part 2 of the study
  • No clinically significant abnormalities that would have interfered with the study assessments, as judged by the investigator


Geographical Location
Canada, Germany, United Kingdom, United States

Number of Participants
≤50 (≥18 years)

Primary Endpoint

Baseline to 5–9 days after last dose of study drug

  • Number of subjects with adverse events (combined Part 1 and Part 2)
  • Number of adverse events (combined Part 1 and Part 2)

Secondary Endpoint

Between Days 14 and 28

  • Change from baseline (BL) in nasal potential difference (combined Part 1 and Part 2)
  • Change from BL in percent predicted forced expiratory volume in 1 second (combined Part 1 and Part 2)
  • Change from BL in the Cystic Fibrosis Questionnaire-Revised score (Part 2 only) (Respiratory Domain Score)
  • Change from baseline in maximum sweat chloride concentration (combined Part 1 and Part 2)

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  • Experimental Ivacaftor Group A

Subjects in Part 1 first received 25 mg or 75 mg of ivacaftor every 12 hours (q12h) for 14 days, then crossed over to receive the alternate dose for another 14 days.

  • Experimental: Ivacaftor Group B

Subjects in Part 1 first received 75 mg or 150 mg of ivacaftor q12h for 14 days then crossed over to receive the alternate dose for another 14 days.

  • Experimental: Ivacaftor Group C

Subjects in Part 2 received 150 mg or 250 mg of ivacaftor q12h for 28 days

  • Placebo Comparator

Subjects received placebo in Part 1 and  received placebo in Part 2 q12h for 28 days each in Part 1 and Part 2 of the study



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 Mar;13(2):139-47. PubMed PMID: 24660233; PubMed Central PMCID: PMC4102431.

Accurso FJ, Rowe SM, Clancy JP, Boyle MP, Dunitz JM, Durie PR, Sagel SD, Hornick DB, Konstan MW, Donaldson SH, Moss RB, Pilewski JM, Rubenstein RC, Uluer  AZ, Aitken ML, Freedman SD, Rose LM, Mayer-Hamblett N, Dong Q, Zha J, Stone AJ, Olson ER, Ordoñez CL, Campbell PW, Ashlock MA, Ramsey BW. Effect of VX-770 in persons with cystic fibrosis and the G551D-CFTR mutation. N Engl J Med. 2010 Nov 18;363(21):1991-2003. doi: 10.1056/NEJMoa0909825. PubMed PMID: 21083385; PubMed Central PMCID: PMC3148255.

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