Introduction: The triple combination, Elexacaftor/Tezacaftor/Ivacaftor (???), significantly improves many aspects of CF (1).

Aim: The aim of the study was to assess degree of adherence to inhaled medication before and after ETI initiation.

Methods: This was a multi- center retrospective study of 71 people with CF (PwCF) from 3 CF centers of Greece. Participants were >18 years old and had received ETI for at least 1 year. Adherence was assessed by the Medication Possession Ratio (MPR), i.e the ratio of the number of doses received from the pharmacy in one year to the number of prescribed doses during the same year. Adherence was considered low if cMPR was <0.5, moderate if it was 0.5-0.79 and high if it was ? 0.8

Results: 38 women and 33 men, with mean age 31.8±9.2 years were included. After ETI, weight improved from 58.0±10.9Kg to 62.1±10.9Kg, (p<0.001), FEV1 from 47.5 ± 19.8 to 57.1 ± 21.8%(p<0.001) and FVC from 66.4 ± 22.3 to 78.4 ± 21.6% (p<0.001). P.aeruginosa was isolated in sputum in 80% of patients before and 61.2% after ETI. Days of iv antibiotics decreased from 29.2 ± 37.6 to 5.6 ± 13.9 (p<0.001). Total adherence after ETI initiation decreased from 63% to 43%. Before ETI adherence was low in 29.6%, moderate in 32.4% and high in 38% of PwCF. Degree of adherence significantly changed after ETI with 56.3%, 22.5% and 21.1% of PwCF presenting with low moderate and high adherence respectively (p<0.001)

Conclusion: ETI is a promising combination. The need for maintenance treatment after ETI initiation remains to be seen in large prospective trials.

1.Middleton PG et al. ETI for CF with a single phe508del allele. N Engl J Med 2019;381(19):1809?19