Reversal of cylindrical bronchial dilatations in a subset of adults with cystic fibrosis treated with elexacaftor/tezacaftor/ivacaftor.

Background

This study sought to evaluate the impact of elexacaftor/tezacaftor/ivacaftor (ETI) on lung structural abnormalities in adults with cystic fibrosis (awCF) with a specific focus on the reversal of bronchial dilatations.

Methods

Chest computed tomography (CT) scans performed prior to and 12 months after initiation of ETI were visually reviewed for possible reversal of bronchial dilatations. AwCF with and without reversal of bronchial dilatations (the latter served as controls, with three controls per case) were selected. Visual Brody score, bronchial and arterial diameters, and lung volume were measured on CT.

Results

Reversal of bronchial dilatations was found in 12/235 (5%) awCF treated with ETI. 12 awCF with and 36 without reversal of bronchial dilatations were further analysed (male 56%, mean±sd age 31.6±8.5 years, F508del/F508del CFTR 54% and mean forced expiratory volume in 1 s 58.8±22.3% predicted). The Brody score improved overall from 79.4±29.8 to 54.8±32.3 (p<0.001). Reversal of bronchial dilatations was confirmed by a decrease in bronchial lumen diameter in cases from 3.9±0.9 to 3.2±1.1 mm (p<0.001), whereas it increased in awCF without reversal of bronchial dilatations (from 3.5±1.1 to 3.6±1.2 mm; p=0.002). Reversal of bronchial dilatations occurred in cylindrical (not varicose or saccular) bronchial dilatations. Lung volumes decreased by -6.6±10.7% in awCF with reversal of bronchial dilatations but increased by +2.3±9.6% in controls (p=0.007).

Conclusions

Although bronchial dilatations are generally considered irreversible, ETI was associated with reversal, which was limited to the cylindrical bronchial dilatation subtype, and occurred in a small subset of awCF. Initiating ETI earlier in life may reverse early bronchial dilatations.

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