VX-809

VX-809 is a CFTR modulator with EC50 of 0.1 μM. VX-809 increases chloride secretions by 14% in human bronchial epithelial cells. Unlike VX-770, VX-809 is not a CFTR potentiator, as acute addition of VX-809 has no effect on F508del-CFTR function. VX-809 has been shown to correct the folding and processing of CFTR in F508del mutation cells in vitro. Pharmacodynamic data showed that VX-809 improved CFTR function in at least one organ (sweat gland). VX-809 reduced elevated sweat chloride values in a dose-dependent manner (p=0.0013) that was statistically significant in the 100 and 200 mg dose groups. VX-809 was more efficacious and selective for CFTR than previously reported CFTR correctors. VX-809 is currently in a phase II study alone and in combination with VX-770 in cystic fibrosis (CF) patients with the F508del-CFTR mutation.