To learn whether the effect of extracellular phosphate was also observed when F508del-CFTR was rescued by elexacaftor-tezacaftor-ivacaftor (ETI), fully differentiated epithelia of CF hAECs homozygous for F508del-CFTR were incubated at 37°C for 24 h with the triple drug combination [27], before epithelia were mounted in Ussing chambers (Fig. 4). The gene discussed is CFTR; the disease is cystic fibrosis.