A NEW study highlights the value of the lung clearance index (LCI) as a sensitive marker for lung improvement in people with cystic fibrosis (pwCF) undergoing elexacaftor/tezacaftor/ivacaftor (ETI) therapy, even when forced expiratory volume in one second (FEV1) changes are minimal.
The study involved 129 patients aged 12 to 36 at a specialised CF centre in Italy. Researchers aimed to evaluate lung function using LCI2.5, which detects subtle changes in airway function, over a 12-month period.
While most participants experienced clinically meaningful FEV1 improvements, 15.5% did not achieve the minimal clinically important difference (MCID) of 3%. Interestingly, this group had better baseline lung function (FEV1 ≥ 90%). Despite minimal FEV1 changes, they showed a significant improvement in LCI2.5, with an average reduction of 1.44 units at 12 months. In contrast, patients with more significant FEV1 improvements showed greater LCI2.5 reductions of 2.64 units.
“These findings underscore the importance of using LCI to assess treatment response, particularly in individuals with near-normal baseline spirometry,” the authors noted.
The study demonstrates that LCI2.5 can identify meaningful lung function improvements in pwCF who fail to show significant FEV1 changes. Incorporating LCI into clinical practice could provide a more comprehensive evaluation of ETI therapy effectiveness, ensuring that subtle but impactful improvements are recognised in cystic fibrosis management.
Aleksandra Zurowska, EMJ
Reference
Daccò V et al. Lung Clearance Index Improves in People with Cystic Fibrosis not Achieving a Clinical Important Difference in Forced Expiratory Volume in One Second After Elexacaftor/Tezacaftor/Ivacaftor Therapy. Lung. 2025; DOI: 10.1007/s00408-024-00768-1.
