CFTR and cystic fibrosis: Concerning the effects on pulmonary exacerbations, a phase 3, randomised, double-blind, placebo-controlled trial conducted in patients with CF ≥ 12 years old, heterozygous for the F508del CFTR mutation and a minimal-function mutation, has shown that the treatment with ETI resulted in a 63% lower annualized rate of exacerbations compared to placebo [64].