Respiratory Oscillometry and Multimodal Lung Function Assessment of Elexacaftor/Tezacaftor/Ivacaftor Response in Children and Young Adults With Cystic Fibrosis

ABSTRACT Background To date, there is no data on forced oscillation technique (FOT) as a tool to evaluate elexacaftor/tezacaftor/ivacaftor (ETI) modulator in young patients with cystic fibrosis (pwCF). Objective Our study aimed to assess the effect of a 6‐month ETI treatment on FOT parameters and compare it to the effect on spirometry and nitrogen multiple‐breath washout (N 2 MBW) parameters. Method Forty‐nine pwCF (median age 12.39 years, 59.2% male) were assessed with spirometry, N 2 MBW, and FOT before and 3 and 6 months after receiving ETI. The trends in changes of spirometric and FOT parameters were compared among pwCF of different disease severity and in the three patient groups according to their mutation group, that is, F/F, F/non‐F, and non‐F/non‐F. Panel regression was applied to define the predictors of LCI. Results A significant change was observed 6 months after receiving ETI in height, weight, BMI, Rs5z‐score, Xs5z‐score, AXz‐score, FEV 1 z‐score, FVCz‐score, FEF 25‐75 z‐score, LCI and sGrs ( p < 0.01). FOT followed a similar trend in parameters' change with spirometry and N 2 MBW three and 6 months after ETI among different severity groups based on LCI ( p < 0.05). Genotype group was found to have a minor role in ETI efficacy; a significant improvement was found in the non‐F/non‐F group in all pulmonary tests ( p < 0.01). Conclusions Our preliminary data suggest that oscillometry parameters showed a significant improvement after ETI treatment among all genotype groups. More data are required to assess whether and which FOT parameters could be used as surrogates of LCI or spirometry for the long‐term follow‐up of pwCF.