VX-809
(Cystic Fibrosis)

VX-809 is the second investigational oral drug candidate for the treatment of cystic fibrosis (CF) to be advanced into development as part of a successful collaboration with the Cystic Fibrosis Foundation Therapeutics, Inc. (CFFT).

Cystic fibrosis is caused by defective or missing CFTR proteins, which result in poor ion flow across cell membranes, including in the lung, and the accumulation of abnormally thick, sticky mucus that leads to chronic lung infections and progressive lung damage. In people with the F508del mutation, CFTR proteins do not reach the cell surface in normal amounts. VX-809, known as a CFTR corrector, aims to increase CFTR function by increasing the trafficking, or movement, of CFTR to the cell surface. In people with the G551D mutation, CFTR proteins do not function normally at the cell surface. VX-770, known as a CFTR potentiator, aims to increase the function of defective CFTR proteins by increasing the gating activity, or ability to transport ions across the cell membrane, of CFTR at the cell surface.

Vertex is conducting an exploratory Phase 2 clinical trial to evaluate combination regimens of VX-770 and VX-809 in people with the most common mutation in CF, known as F508del. Vertex recently completed the first part of the trial and is on track to initiate the second part of the trial in September 2011.