BACKGROUND: While studies have consistently reported improvements in lung function during elexacaftor/tezacaftor/ivacaftor (ETI) therapy for people with cystic fibrosis (pwCF), individual response predictors remain poorly understood and there is limited real-world data relating to children aged 6-11 years. METHODS: Lung function data from the German CF Registry 2020-2024 were analysed before and up to 24 months after ETI therapy initiation in adults, adolescents and children aged
