Study of the Effect of VX-770 on Hyperpolarized Helium-3 Magnetic Resonance Imaging in Subjects With Cystic Fibrosis and the G551D Mutation

• Status: Completed
• Trial end date: 2013-02-01

Summary

Cystic Fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The encoded protein, CFTR, is an epithelial chloride ion channel responsible for aiding in the regulation of salt and water absorption and secretion in various tissues. Although the disease affects multiple organs, the leading cause of mortality is the progressive loss of lung function. Obstruction of airways with thick mucus, chronic bacterial infection of the airways, and inflammatory response are all thought to play a role in causing lung damage. Through its function as a chloride channel, CFTR is believed to be integral in epithelial ion and water transport and hence, maintaining the normal hydration of lung secretions.

VX-770 (ivacaftor) is a potent and selective potentiator of wild-type, G551D, F508del, and R117H forms of human CFTR. Based on in vitro studies and pharmacologic, pharmacokinetic (PK), and safety profiles, VX-770 has been selected for clinical development as a possible treatment for patients with CF.

Hyperpolarized noble gas magnetic resonance imaging (HG-MRI) is a promising new means of assessing lung function by direct imaging of certain non-radioactive isotopes of an inert noble gas, such as helium or xenon. Through this technique, high-resolution 3-dimensional images of lung ventilation can be obtained in both pediatric and adult patients during a single short breath-hold following inhalation of the gas.

This is a 2-part study to evaluate the effect of VX-770 on hyperpolarized helium-3 magnetic resonance imaging (3He-MRI), and to evaluate the safety and efficacy of VX-770 in subjects aged 12 years and older with CF who have the G551D-CFTR mutation. Part A is a single-blind, placebo-controlled study that includes 4 weeks of VX-770 treatment and 4 weeks of placebo treatment. Part B is an open-label, 48 week study of long-term effect of VX 770 on hyperpolarized 3He-MRI.

• Phase: Phase 2

Details

• Lead Sponsor: Vertex Pharmaceuticals Incorporated
• Collaborators: Cystic Fibrosis Foundation; Cystic Fibrosis Foundation Therapeutics
• Treatments: Ivacaftor