The recent advancement of CFTR modulatorshas provided remarkableclinical impact on care and overall prognosis among patients withCF.24−26 Currently approved CFTR potentiators and correctorsare available in the United States for over 90% of the CF population.27 For the remaining ∼10%, many of whomencode rare or refractory CFTR variants, and for patients approvedfor modulator treatment who respond poorly, experience toxicity, orcannot afford the high cost of these drugs, alternative CFTR modulatorsrepresent a priority in the field. This evidence concerns the gene CFTR and cystic fibrosis.