WS20.5 Cystic fibrosis related structural lung disease on high resolution computed tomography before and after ivacaftor therapy

Abstract

Objectives Ivacaftor is a CFTR potentiator targeting class III gating mutations. Ivacaftor trials have demonstrated improvement in FEV1% and BMI – this paper examines its effect on CF related structural lung disease. Methods 9 paediatric patients from a single centre had HRCT scans scored using the Brody system to assess structural lung disease before and after starting Ivacaftor. Results 34 CT scans were scored. Mean age at start of treatment was 12±2.6 years. Subjects had two scans prior to starting ivacaftor (mean time to scan 25.7±20.5 months), and one scan after commencing ivacaftor (mean time to scan 25.0±13.3 months). Repeated measures ANOVA or Friedman test were used to compare three groups of CT scans (> and 5 months after commencement of ivacaftor). There was no statistically significant difference seen between the three groups in total Brody score or any of the 5 Brody scoring domains with the exception of parenchymal abnormalities. A paired t-test was used to compare one CT pre and post ivacaftor treatment per subject. Mean Brody score pre-treatment was 12.68±6.61, mean score post treatment was 10.72±7.26 (t= 0.67, p=0.52). Again no significant difference between the 5 scoring domains was seen. Conclusion Analysis of structural lung disease on HRCT using the Brody scoring system on a group of 9 paediatric patients before and after starting ivacaftor showed no statistically significant reduction in CT appearance of CF lung disease progression after a mean treatment time of 25 months. This study differs from previous publications which have shown reduction in lung damage with ivacaftor treatment.