These findings are in contrast with previous studies showing that chronic ivacaftor exposure limits the response to corrector compounds (25, 26, 28, 29) but concordant with other reports of dose-dependent increase in constitutive F508del-CFTR–mediated currents by ivacaftor treatment in combination with ET (29, 44), highlighting the impact of culture conditions on pharmacological rescue of CFTR in CF airway epithelial cultures. This evidence concerns the gene CFTR and cystic fibrosis.