Ivacaftor, the potentiator component of elexacaftor/ivacaftor/tezacaftor, has been an effective therapy for the treatment of individuals with CF harboring gating and residual function CFTR mutations (Accurso et al., 2010; Bratcher et al., 2019; Davies et al., 2013, 2016; Guimbellot et al., 2019; Hebestreit et al., 2013; McGarry et al., 2017; McGarry & Nielson, 2013; Moss et al., 2015; Nick et al., 2020; Ramsey et al., 2011; Rosenfeld et al., 2018, 2019; Salvatore et al., 2019). The gene discussed is CFTR; the disease is cystic fibrosis.