WS08.03: Remodelling of cystic fibrosis respiratory microbiota in response to extended elexacaftor/tezacaftor/ivacaftor therapy

H. Gavillet*, L. Hatfield, M. Hardman, G.G. Einarsson, C.S. Thornton, M.D. Parkins, J. Duckers, J.M. Bomberger, Y. Hilliam, S.E. Lee, R.W. Lord, A. Jones, A. Horsley, T.W.V. Daniels, C.C. Teneback, M.J. Wargo, K. Schutz, D.W. Rivett, C. van der Gast

*Corresponding author for this work

Research output: Contribution to journalMeeting Abstractpeer-review

Abstract

Objectives
The introduction of the highly effective CFTR modulator Elexacaftor/Tezacaftor/Ivacaftor (ETI) has revolutionised clinical outcomes for adults with CF (awCF) eligible for treatment. Despite this little is understood about the long-term impact of ETI on the respiratory microbiota in awCF. In this multi-centre study, we investigated changes to the respiratory microbiota of awCF from before onset of ETI therapy to on-ETI therapy of up to 3 years.
Methods
Respiratory samples were collected from 303 awCF from 6 centres in the UK (Cardiff, Manchester, & Southampton), Canada (Calgary), and USA (Dartmouth & Vermont). This consisted of pre-ETI samples stratified to severe, moderate, and mild disease groups based on %FEV1, and on-ETI samples taken at approximately 6 months, 1, 2, & 3 years. Samples from 11 non-CF healthy participants were included as a comparator group. Microbiota sequencing was performed on all samples.
Results
Microbiota diversity increased with therapy duration. With diversity at years 2 and 3 being comparable (P>0.05) to that observed in the mild disease pre-ETI and healthy groups. Microbiota composition became increasingly similar to mild CF/healthy groups with increasing therapy duration but was still significantly different (P<0.05) at 3 years. Dominance of CF pathogens reduced with therapy duration, with a shift to microbiota characterised by strict anaerobes associated with better clinical outcomes. Despite the reduction in abundance many CF pathogens still persisted.
Conclusions
Long-term ETI therapy resulted in positive changes in the respiratory microbiota, typically associated with better clinical outcomes and microbiota more closely resembling mild CF/healthy microbiota. Despite a positive trajectory towards a healthy-like microbiota, we posit that progression in awCF is impeded by the cumulative effects of progressive airway and lung parenchymal damage, along with the impacts of long-term and continued antibiotic therapy.
Original languageEnglish
Pages (from-to)S16-S16
Number of pages1
JournalJournal of Cystic Fibrosis
Volume24
Issue numberSupplement 1
Early online date3 Jun 2025
DOIs
Publication statusPublished - Jun 2025
Event48th European Cystic Fibrosis Conference - Allianz MiCo, Milan, Italy
Duration: 4 Jun 20257 Jun 2025
https://www.ecfs.eu/milan2025

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