LONGITUDE: An observational study of the long-term effectiveness of elexacaftor/tezacaftor/ivacaftor in people aged ≥12 years with cystic fibrosis using data from the United Kingdom Cystic Fibrosis Registry - 2-year analysis.

BACKGROUND

The cystic fibrosis (CF) transmembrane conductance regulator modulator (CFTRm) elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) has demonstrated efficacy and safety in clinical trials and emerging observational studies in people with CF. This study evaluated the real-world impact of ELX/TEZ/IVA in a large cohort of people with CF in the UK.

METHODS

LONGITUDE is an observational, registry-based cohort study using data from the UK CF Registry to evaluate outcomes of ELX/TEZ/IVA in people aged ≥6 years who initiated ELX/TEZ/IVA from August 2019. Key outcomes included percent predicted forced expiratory volume in 1 s (ppFEV1), body mass index (BMI), pulmonary exacerbations (PEx), lung infections, transplants, deaths, and treatment discontinuation. We report results of people ≥12 years with data up to December 31, 2022.

RESULTS

A total of 5187 people were included (mean follow-up 19.1 months). ppFEV1 improvements were observed at 2 years (10.2; 95 % CI: 9.6, 10.8; n = 1448). A clinically meaningful difference in the annual change of ppFEV1 between ELX/TEZ/IVA-treated people and historical CFTRm-naïve controls was observed, with those treated with ELX/TEZ/IVA having less of a decline in lung function over time by 1.1 percentage points (95 % CI: 0.9, 1.4). A 64.7 % reduction in the rate of PEx, increase in BMI by 1.7 kg/m2 (SD: 2.3), reduced lung infections, and low number of lung transplants and deaths were also observed.

CONCLUSIONS

People with CF aged ≥12 years in the UK who initiated ELX/TEZ/IVA had sustained improvements in multiple CF-related health outcomes, consistent with results from clinical trials. These results support the positive impact of ELX/TEZ/IVA on the lives of people with CF.