CFTR and cystic fibrosis: Furthermore, in CF-patient-derived HBE cells, 43 increased F508del-CFTR ion channel activity by ∼3-fold(EC50 ∼ 10 nM) and further potentiated the therapeuticeffect of the known corrector 3 by ∼2-fold.178 All of these data demonstrated that the authorssuccessfully developed a drug-like cyclized peptidyl molecule as apotent, selective, and with high proteolytic stability inhibitor ofCAL-CFTR PPI.