VX-770 was subsequently assessed in combination with the CFTR corrector lumacaftor (VX-809), which increases the amount of CFTR reaching the cell surface, and showed mild improvements in FEV1 (2.6–4 percent points) and decreases in pulmonary exacerbations (30–39%) in the F508del homozygous population, which represents the global majority of CF patients22–24. Here, CFTR is linked to cystic fibrosis.