These organoids have facilitated the assessment of the cystic fibrosis transmembrane conductance regulator (CFTR) function in individual patients in vitro, and in turn the effect of different drugs used to treat cystic fibrosis, including VX-809 (lumacaftor) and VX-770 (ivacaftor) (34). The gene discussed is CFTR; the disease is cystic fibrosis.