CFTR and cystic fibrosis: Therefore, it is not surprising that the magnitude of the CFTR-dependent ΔIeq (ΔFsk-Ieq and ΔCFTRInh-172-Ieq) responses were greater in 2D HIO compared with HNE cultures exemplified in 2D HIO generated from a non-CF individual and in 2D HIO from two F508del/F508del patients treated with tezacaftor/elexacaftor/ivacaftor (TEZ/ELEXA/IVA or VX-661+VX-445+VX-770) (Figs 1E and S1).