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

This study has been completed.
Cystic Fibrosis Foundation Therapeutics
Information provided by (Responsible Party):
Vertex Pharmaceuticals Incorporated Identifier:
First received: August 4, 2009
Last updated: April 22, 2014
Last verified: April 2014
Results First Received: February 27, 2012  
Study Type: Interventional
Study Design: Allocation: Randomized;   Endpoint Classification: Safety/Efficacy Study;   Intervention Model: Parallel Assignment;   Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor);   Primary Purpose: Treatment
Condition: Cystic Fibrosis
Interventions: Drug: Ivacaftor
Drug: Placebo

  Participant Flow
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Recruitment Details
Key information relevant to the recruitment process for the overall study, such as dates of the recruitment period and locations
Part A started on 21 September 2009 (date of first informed consent). After obtaining consent and assent (where applicable), screening evaluations were completed during a period of 2 to 5 weeks (Day -35 to Day -15) before the first dose of study drug.

Pre-Assignment Details
Significant events and approaches for the overall study following participant enrollment, but prior to group assignment
In Part A, a total of 140 subjects were enrolled. All received at least 1 dose of the study drug. A 2-week run-in period was included to establish the baseline assessments on Day 1 after ensuring that subjects were properly adhering to their cystic fibrosis (CF) medication regimens.

Reporting Groups
Placebo Oral tablet every 12 hours (q12h) for 16 weeks
150 mg Ivacaftor q12h Oral tablet of 150 mg of ivacaftor q12h for 16 weeks

Participant Flow:   Overall Study
    Placebo     150 mg Ivacaftor q12h  
STARTED     28 [1]   112 [2]
COMPLETED     26 [3]   104 [3]
NOT COMPLETED     2     8  
Adverse Event                 2                 3  
Lost to Follow-up                 0                 1  
Noncompliance with Study Requirements                 0                 2  
Prohibited Medication                 0                 1  
Early Termination Per Sponsor Decision                 0                 1  
[1] All subjects who received at least 1 dose of study drug (placebo)
[2] All subjects who received at least 1 dose of study drug (ivacaftor)
[3] Completed Part A Treatment Period (Through Week 16)

  Baseline Characteristics

  Outcome Measures
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1.  Primary:   Absolute Change From Baseline in Percent Predicted Forced Expiratory Volume in 1 Second (FEV1) Through Week 16   [ Time Frame: baseline through 16 weeks ]

2.  Secondary:   Absolute Change From Baseline in Cystic Fibrosis Questionnaire-Revised (CFQ-R) Score Through Week 16 (Respiratory Domain Score, Pooled)   [ Time Frame: baseline through 16 weeks ]

3.  Secondary:   Absolute Change From Baseline in Sweat Chloride Concentration Through Week 16   [ Time Frame: baseline through 16 weeks ]

4.  Secondary:   Rate of Change From Baseline in Weight Through Week 16   [ Time Frame: baseline to 16 weeks ]

  Serious Adverse Events

  Other Adverse Events

  Limitations and Caveats
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Limitations of the study, such as early termination leading to small numbers of participants analyzed and technical problems with measurement leading to unreliable or uninterpretable data
This study was primarily designed to collect safety information for subjects treated with ivacaftor and was not powered to detect a statistically significant treatment effect in any efficacy endpoints.

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