Real-world impact of Elexacaftor-Tezacaftor-Ivacaftor treatment in young people with Cystic Fibrosis: A longitudinal study

Background

Elexacaftor, Tezacaftor, Ivacaftor (ETI) became available in the UK in August 2020 to treat people with Cystic Fibrosis (CF) aged >12 years. We report a real-world study of clinical outcomes in young people treated with ETI at our CF centre within the first two years of its availability.

Methods

Participants aged 12–17 were identified within our clinic, with demographic data supplemented by the UK CF registry. Comprehensive outcome data spanning two years pre- and two years post-initiation of CFTR modulators were compiled from various local sources, including patient records, medication delivery logs, and clinical notes.

Results

Of the 62 patients started on ETI (32 male, mean age 13.3 years), most (76 %) were homozygous for the F508del mutation. Three discontinuations occurred: one pregnancy, two related to side effects. Adherence was high (Proportion of Days covered >90 % both years). Following ETI initiation there was a significant increase in mean FEV1% (+11.7 units; 95 % CI 7.4–15.6), sustained throughout the two-year treatment period. There was no association between baseline lung function and the degree of improvement or rate of decline post-treatment. Improvements were similar for all treatable genotypes. BMI z-score increased by 0.25 units after four months of treatment, returning to baseline by 24 months. Intravenous antibiotic use decreased by 88 % (median IV days/year reduced from 32 to 4 days, p < 0.01).

Conclusions

ETI use in adolescents in a real-world setting led to sustained improvements in health outcomes, consistent with those seen in open trial extension studies.