Retrospective UK CF Registry cohort (2009–2023) examining how initiation of Elexacaftor/Tezacaftor/Ivacaftor (ETI) affected prescribing of traditional maintenance therapies (inhaled antibiotics, dornase alfa, hypertonic saline, azithromycin, flucloxacillin), with logistic regression identifying predictors of stopping each therapy.
By 3 years post-ETI, those previously on dual modulator therapy had absolute reductions of 15.1% in inhaled antibiotics, 14.7% in dornase alfa, and 9.8% in hypertonic saline. Older age, higher BMI, and worse lung function lowered the odds of stopping inhaled antibiotics and azithromycin. Patients in the lowest socioeconomic quintile were significantly less likely to stop azithromycin (OR 0.61; 95% CI 0.40–0.91) or flucloxacillin (OR 0.54; 95% CI 0.33–0.86) vs. the highest quintile.
Retrospective registry design limits causal inference. Prescriptions reflect prescribing rather than confirmed adherence or dispensing. There is a limited evidence base for safe antibiotic withdrawal in CF, making it unclear whether observed deprescribing was clinically appropriate.
After starting ETI, expect meaningful but incomplete reductions in maintenance therapies — roughly 1 in 7 patients still carry their full inhaled antibiotic and mucoactive burden at 3 years. Clinicians should be aware that socioeconomic disadvantage and poorer lung function are associated with less deprescribing, warranting targeted review rather than blanket discontinuation.
