BACKGROUND: Elexacaftor-tezacaftor-ivacaftor (ETI) therapy has shown improvement in lung function, BMI and reduction in pulmonary exacerbations but the impact of genotype and severity of lung disease on heterogeneity of ETI efficacy in real life is not known. METHODS: This is a prospective observational study. Clinical data at baseline and at one-year of therapy were compared for the total cohort and for two subgroups
genotype [homozygous vs. heterozygous for F508del], and severity of lung disease at ETI initiation (ppFEV RESULTS: Among the total cohort of 115 pwCF, median age of 23 (17, 32) years, 66 (58 %) were homozygous, 76 (66 %) had ppFEV CONCLUSION: ETI therapy improved clinical outcomes in pwCF which were impacted by severity of underlying lung disease.