Effect of Lumacaftor/Ivacaftor in Children With Cystic Fibrosis Homozygote for F508del on Small Airway Function

To obtain prospective real world data of the effect of lumacaftor/ivacaftor or tezacaftor/ ivacaftor on small airway disease in children aged 6-18 years with cystic fibrosis (CF) homozygous for F508del. The effect of the medication on small airway disease is evaluated by measurement of multiple breath washout (MBW) with its outcome parameter lung clearance index (LCI) and the Perth-Rotterdam Annotated Grid Morphometric Analysis for CF (PRAGMA-CF) cpmputed tomography (CT) score. In addition the relation between changes in LCI and PRAGMA-CF score is evaluated.

Multi-center observational study. Duration 12 months after the start of lumacaftor/ ivacaftor or tezacaftor/ ivacaftor . To collect these data and to assist in clinical decisions regarding initiation and continuation of lumacaftor/ivacaftor or tezacaftor/ ivacaftor, the investigators of the CF center (Beatrix Children's Hospital, University Medical Center Groningen (UMCG), the Netherlands) developed an extensive protocol of testing before children aged 6-18 years start therapy and during the first year after start. The protocol includes the following tests: growth parameters, sweat test, lung function testing (spirometry, MBW, body plethysmography), blood test panel (AST, ALT, alkalic phosphatase (AF), total and direct bilirubin, LDH), fecal elastase, high resolution (HR)CT and CF quality of life questionnaires. These tests are repeated at regular intervals. Multi-center observational study. Duration 12 months after the start of lumacaftor/ ivacaftor or tezacaftor/ ivacaftor .