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Drug & research development » Clinical trials » NCT00953706

Study of Ivacaftor in Cystic Fibrosis Subjects Aged 12 Years and Older Homozygous for the F508del-CFTR Mutation (DISCOVER)

Official title: A Phase 2, Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Study to Evaluate the Safety and Efficacy of VX-770 in Subjects Aged 12 Years and Older With Cystic Fibrosis Who Are Homozygous for the F508del-CFTR Mutation

Clinical Trials gov number: NCT00953706

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Purpose: To evaluate the safety and efficacy of ivacaftor in CF patients aged ≥12 years and homozygous for the F508del-CFTR mutation.

Phase: 2

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

Study sponsor: Vertex Pharmaceuticals Incorporated; Cystic Fibrosis Foundation Therapeutics

  • Confirmed diagnosis of cystic fibrosis (CF) and homozygous for F508del-CFTR mutation
  • Forced expiratory volume in 1 second (FEV1) of at least 40% of predicted normal for age, gender, and height
  • Willing to use at least 2 highly effective birth control methods during the study
  • No clinically significant abnormalities that would have interfered with the study assessments, as judged by the investigator
  • Able to understand and comply with protocol requirements, restrictions, and instructions and likely to complete the study as planned, as judged by the investigator


Geographical Location
United States

Number of Participants
101-1000 (≥12 years)

Primary Endpoint

Absolute change from baseline in percent predicted forced expiratory volume in 1 second (FEV1) through Week 16

Secondary Endpoint

  • Absolute change from baseline (BL) in Cystic Fibrosis Questionnaire-Revised score through Week 16 (Respiratory Domain Score, Pooled)
  • Absolute change from BL in sweat chloride concentration through Week 16
  • Rate of change from BL in weight through Week 16

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  • Placebo Comparator:

     Subjects in Part A who received placebo every 12 hours (q12h) for 16 weeks.

  • Experimental:

     Subjects in Part A who received 150 mg of ivacaftor q12h for 16 weeks.



Flume PA, Liou TG, Borowitz DS, Li H, Yen K, Ordoñez CL, Geller DE; VX 08-770-104 Study Group. Ivacaftor in subjects with cystic fibrosis who are homozygous for the F508del-CFTR mutation. Chest. 2012 Sep;142(3):718-24. PubMed PMID: 22383668; PubMed Central PMCID: PMC3435140.

View Trial Results