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Drug & research development » Clinical trials » NCT01262352

Study of the Effect of Ivacaftor on Lung Clearance Index in Subjects With Cystic Fibrosis and the G551D Mutation

Official title: A Phase 2, Randomized, Double-Blind, Placebo-Controlled, Crossover Study to Evaluate the Effect of VX-770 on Lung Clearance Index in Subjects With Cystic Fibrosis, the G551D Mutation, and FEV1 >90% Predicted

Clinical Trials gov number: NCT01262352

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Purpose: To evaluate the effect of ivacaftor on lung clearance index (LCI) in CF patients aged ≥6 years who have the G551D-CFTR mutation on ≥1 allele.

Phase: 2

Type: Interventional, randomized, double-blind, crossover assignment

Study sponsor: Vertex Pharmaceuticals Incorporated; Cystic Fibrosis Foundation Therapeutics

  • Male or female subjects with confirmed diagnosis of CF
  • Must have the G551D-CFTR mutation in ≥1 allele
  • FEV1 >90% of predicted normal for age, gender, and height


Geographical Location
Canada, United Kingdom, United States

Number of Participants
≤50 (≥6 years)

Primary Endpoint

Absolute change from baseline in lung clearance index (LCI) from baseline through Day 29

Secondary Endpoint

Baseline (BL) through to Day 29

  • Absolute change from BL in percent predicted FEV1
  • Change from BL in sweat chloride
  • Change from BL in CF Questionnaire-Revised Score (Respiratory Domain Score, Pooled)

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  • Experimental treatment sequence: Ivacaftor administered in Treatment Period 1 and placebo administered in Treatment Period 2.

 Ivacaftor 150 mg tablet, oral use, twice daily every 12 hours (q12h)

 Placebo tablet, oral use, twice daily every 12 hours (q12h)

  • Experimental treatment sequence 2: Placebo administered in Treatment Period 1 and ivacaftor administered in Treatment Sequence 2.

 Ivacaftor 150 mg tablet, oral use, twice daily every 12 hours (q12h)

 Placebo tablet, oral use, twice daily every 12 hours (q12h)

Each treatment period lasted 28 days, with a 28-day washout between treatment periods.



Davies J, Sheridan H, Bell N, Cunningham S, Davis SD, Elborn JS, Milla CE, Starner TD, Weiner DJ, Lee PS, Ratjen F. Assessment of clinical response to ivacaftor with lung clearance index in cystic fibrosis patients with a G551D-CFTR mutation and preserved spirometry: a randomised controlled trial. Lancet Respir Med. 2013 Oct;1(8):630-8. doi: 10.1016/S2213-2600(13)70182-6. Epub 2013 Sep 10. PubMed PMID: 24461666.

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