Cystic Fibrosis Foundation - Click here for homepage
Stay Informed  |  Volunteer  |  Clinical Trials

In This Section

Quick Links

Find a Chapter


Study Name: Vertex 770 in Children with CF and the G551 Mutation (ENVISION)
Study Type: Interventional
Intervention Category: CFTR Modulation
Study Sponsor: Vertex
Study Phase: 3
Recruitment Status: Trial Completed
Study Drug(s): Kalydeco
Number of Participants Being Recruited: 30
Single / Multi-Center: Multi-Center
Cystic Fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The CFTR protein is located on the cell membrane of the airways and sweat ducts. It is a chloride ion channel responsible for aiding in the regulation of salt and water absorption and secretion in tissues. Potentiators are pharmacological agents that increase the chloride ion transport properties of the channel. The increase in CFTR chloride ion channel opening may prevent hyperabsorption of water in the airway tissues, allowing for more favorable maintenance of airway hydration in people with CF.

This study evaluated a single dose of VX-770 to determine the appropriate dose for Part B of the study. Part B looked at the effectiveness of VX-770 in the pediatric population aged 6 to 11 years who have CF and the G551D mutation and safety over a longer treatment period.
Age: 6 Years - 11 Years
FEV1: 40 - 90 Percent Predicted
P. aeruginosa status: Not applicable
B. cepacia status: Not applicable
Other Primary Eligibility Requirements:

To be included in this study patients must have the G551D-CFTR mutation in at least 1 allele (any known or unknown mutations allowed in second allele).
Note: Detailed eligibility criteria information may be available on If a specific trial listing for this trial is available, a link to the specific listing will be present in the "More Information" section below.
Sponsor Contact Information: Medical Monitor, Vertex
(617) 444-6777
Trial Specific Link on
Clinical Research Terms Glossary: Click here
Primary Efficacy:

This Phase 3 trial evaluates multiple combination regimens of VX-770 and VX-809 in CF patients (Age 6-11) with at least one G551D-CFTR allele. Fifty-two subjects were enrolled and will receive either 150 mg VX-770 or placebo every 12 hours for 48 weeks.
Data reported from an interim analysis showed that the study met its primary endpoint of mean absolute change from baseline in percent predicted FEV1 through week 24, showing a difference of 12.5 percent (p<0.0001). A difference in mean relative improvement from baseline in FEV1 of 17.4 percent compared to placebo was also observed.

Secondary Efficacy:

Significant improvements in weight gain and reduction in sweat chloride were observed through week 24.


At the time of the 24-week analysis, the most commonly reported adverse events were respiratory and comparable across treatment groups.
The summary of data provided here is from a company press release (March 2011). These data may be preliminary and have not been peer-reviewed.


Am J Respir Crit Care Med ;DOI 10.1164

Back to top