Indeed, the resulting CFTRinh-172-sensitive currents were ~2.5-fold greater than those measured in CF hAEC epithelia pre-treated with VX-809 studied in the absence of phosphate (Fig. 3A, B and E), confirming the results obtained with F508del-CFTR-expressing FRT epithelia (Fig. 2). Here, CFTR is linked to cystic fibrosis.