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).
VX-809 may act to restore the function of the cystic fibrosis transmembrane conductance regulator (CFTR) protein, the defective cell membrane protein responsible for the progression of CF. Defects in the CFTR protein affect the transport of chloride and other ions across cells, and lead to the accumulation of thick, sticky mucus in the lungs of patients with CF. This mucus fosters chronic infection and inflammation, and results in irreversible lung damage.
Corrector compounds such as VX-809 are designed to increase the amount of F508del CFTR protein on the surface of cells lining the airway, which may result in an increase in chloride transport across the cell surface in patients with the F508del CFTR mutation.
Vertex recently completed a Phase 2a clinical trial for VX-809. The trial was designed primarily to evaluate the safety and tolerability of multiple doses of VX-809 in patients with CF. In addition to assessing safety, the trial was also designed to evaluate the potential effect of VX-809 on measures of CFTR function. The trial enrolled 89 patients homozygous for the F508del mutation in the CFTR gene, the most common mutation in CF patients. Based on the Phase 2a data, Vertex is now focused on generating key data that may support the initiation of a combination trial of VX-809 with the CFTR potentiator VX-770 in patients with the F508del mutation.
