Real-time breath metabolomics to assess early response to CFTR modulators in adults with cystic fibrosis: an open-label proof-of-concept study

Background The combination of CFTR modulators ivacaftor/tezacaftor/elexacaftor (ETI) achieves unprecedented improvements in clinical symptoms and respiratory function of people with cystic fibrosis. Yet, evaluation is difficult in people with high baseline lung function and the sweat test may vary depending on the type of CFTR mutation. Exhaled breath is a non-invasive sample, rich in personalised metabolic information and breathomics has emerged as a promising tool to monitor and assess therapeutic response. We hypothesised that ETI induces alterations in the breath composition and that these changes may correlate with clinical readouts.