CFTR and cystic fibrosis: However, patients with CF are continuously treated with fixed dual or triple combinations of CFTR correctors (lumacaftor or tezacaftor or elexacaftor and tezacaftor; ET) and the potentiator ivacaftor (15), and subsequent studies in CF models including primary airway epithelial cultures reported that chronic presence of ivacaftor has adverse effects on the pharmacological correction of F508del-CFTR (25–30).