Aim Cystic fibrosis (CF) is a chronic disease with a high prevalence in Ireland. Patients are prescribed nebulised therapy in the form of dornase alfa to act as a mucolytic. The discovery of CFTR modulators has improved clinical outcomes for most patients, however, compliance with traditional therapies has decreased. The aim of this study is to assess compliance with dornase alfa in a paediatric cohort post commencement of triple therapy (tezacaftor, ivacaftor, elexacaftor branded as Kaftrio® in Ireland) over a 6 month period from May 2023 to October 2023.

Material and Method Patient data (n=20) was extracted via pharmacy records from the national on-line prescribing system (‘High Tech Hub’) comparing prescribed dose to dispensed dose of dornase alfa. Patient data was anonymised. Qualitative data is presented comparing the prescribed and dispensed dose (monthly prescriptions filled) over a 6 month period.

Results Patients included were between 6–18 years old. Patients were prescribed dornase alfa regularly (14/20) or as required (6/20). Of the patients with regular prescriptions, 29% (4/14) of patients were adherent with their prescribed medication. 42% (6/14) of patients prescribed dornase alfa regularly did not obtain this medication at any point during the study. Of the 6 patients who were prescribed this medication as required, only one patient utilised it in the study period.

Conclusions Our centre demonstrates a high rate of non-adherence with dornase alfa. Non-adherence is common in patients with a chronic illness like CF particularly since the advent of modulator therapies. It is important to monitor adherence to ensure optimal outcomes, discuss alternate options, support compliance, and identify possible cost savings if medications are not utilized. Records prior to commencement of Kaftrio® are unavailable on our patients therefore a case control comparison is not possible. Also, ‘stockpiling’ of medication may occur (patient obtains medication but does not take) and compliance may be lower than reported.