Changes in Lung Clearance Index in Preschool-aged Patients with Cystic Fibrosis Treated with Ivacaftor (GOAL): A Clinical Trial

The lung clearance index (LCI) measured by multiple-breath washout has been shown to be a sensitive measure to capture lung function abnormalities in patients with CF and is feasible for use in preschool children because it requires minimal cooperation. LCI significantly improved from baseline at both 1 month (median change in LCI from baseline, - 23.6% [IQR, -34.2 to -20.2]; P < 0.001) and 6 months post-treatment (median change in LCI from baseline, - 24.6% [IQR, -31.4 to -20.4]; P < 0.001). [...]rapid and sustained improvements in LCI were demonstrated with ivacaftor therapy that exceeded the between-test reproducibility and thus the physiologically relevant change for quarterly LCI measurements in health, which we recently demonstrated to be 15% in preschool children (10). Lung clearance index as an outcome measure for clinical trials in young children with cystic fibrosis: a pilot study using inhaled hypertonic saline.