Cardiopulmonary exercise test (CPET) in people with Cystic Fibrosis on elexacaftor/tezacaftor/ivacaftor therapy

<bold>Background:</bold> The treatment with Elexacaftor/Tezacaftor/Ivacaftor (ETI) has been associated with relevant improvements in lung function and has the potential to improve exercise capacity. This study aims to assess the change in physical performance and pulmonary function after the first 6 months of ETI. <bold>Methods:</bold> Adult pwCF underwent Cardio Pulmonary Exercise Test (CPET), Spirometry, Diffusion Lung Capacity (DLCO), Lung Clearance Index (LCI), International Physical Activity Questionnaire (IPAQ) and Sino-Nasal Outcome Test (SNOT22) before ETI treatment and after 6 months. Data are reported as mean and ±1standard deviation (sd), change as mean difference with 95% Confidence Intervals (CI). <bold>Results:</bold> In this observational prospective single-center study, a total of 117 adult pwCF (58.1% men) aged 28.8 (9.4) years with FEV1 74.7 (23.2) %predicted were enrolled. After ETI, FEV1 improved by 15 (95%CI: 9 to 21)% points predicted, Wmax by 7.6 (95%CI: 3.1 to 18.3) W whereas intercept decreased by -0.8 (95%CI: -2.1 to 0.5) l/min. FRC/TLC changed by -0.08 (95%CI: -0.19 to 0.04). <bold>Conclusion:</bold> After 6 months, the ability to generate work increased on top of an overall respiratory improvement. The mechanisms responsible for these changes might include the impact of ETI on reducing airway hyperinflation and deserve further investigation in larger trials.