LUM/IVA is currently the only available CFTR modulator for children with CF who are F/F between 2 and 5 years of age and, along with tezacaftor-ivacaftor (TEZ/IVA) and the recently approved elexacaftor-tezacaftor-ivacaftor (ELX/TEZ/IVA), the only CFTR modulator therapy for children with CF who are F/F older than 6 years of age [e.g., (Ramsey and Welsh, 2017; De Boeck, 2020)]. Here, CFTR is linked to cystic fibrosis.