Davies JC, Sermet-Gaudelus I, Naehrlich L, et al. - Given that the CFTR modulator tezacaftor/ivacaftor was generally safe and efficacious and well-tolerated in Phase 3 studies in candidates ≥ 12 years of age with cystic fibrosis (CF) homozygous for the F508del-CFTR mutation or heterozygous with a residual function- CFTR mutation ( F/F or F/RF respectively), researchers assessed efficacy and safety of tezacaftor/ivacaftor over 8 weeks in participants 6 through 11 years of age with these mutations. Candidates were randomized 4:1 to tezacaftor/ivacaftor or a blinding group (placebo for F/F, ivacaftor for F/RF). At least one study drug dose was obtained by 67 candidates. There were no serious adverse events (AEs) or AEs that resulted in the discontinuation or interruption of tezacaftor/ivacaftor. Cough, headache, and productive cough were the most common AEs (≥10%) in participants receiving tezacaftor/ivacaftor. In participants 6 through 11 years of age with F/F or F/RF genotypes, tezacaftor/ivacaftor improved lung function (assessed using LCI) and CFTR function (measured by sweat chloride concentration). Overall, the authors concluded that tezacaftor/ivacaftor was safe and well tolerated. No new safety concerns have been identified.