Clinical response to lumacaftor-ivacaftor in patients with cystic fibrosis according to baseline lung function.

BACKGROUND:Phase 3 trials have demonstrated the safety and efficacy of lumacaftor-ivacaftor (LUMA-IVA) in patients with cystic fibrosis (CF) homozygous for the Phe508del CFTR mutation and percent predicted forced expiratory volume in 1 s (ppFEV1) between 40 and 90. Marketing authorizations have been granted for patients at all levels of ppFEV1. METHODS:To evaluate the safety and effectiveness of LUMA-IVA over the first year of treatment in patients with ppFEV1<40 or ppFEV1≥90 in comparison with those with ppFEV1 [40-90[. Analysis of data collected during a real world study, which included all patients aged ≥12 years who started LUMA-IVA in 2016 across all 47 French CF centers. RESULTS:827 patients were classified into 3 subgroups according to ppFEV1 at treatment initiation (ppFEV1<40, n = 121; ppFEV1 [40-90[, n = 609; ppFEV1≥90, n = 97). Treatment discontinuation rate was higher in ppFEV1<40 patients (28.9%) than in those with ppFEV1 [40-90[(16.4%) or ppFEV1≥90 (17.5%). In patients with uninterrupted treatment, significant increase in ppFEV1 occurred in the ppFEV1 [40-90[subgroup (+2.9%, P<0.001), and in those ppFEV1<40 (+0.5%, P = 0.03) but not in those with ppFEV1≥90 (P = 0.46). Compared with the year prior to initiation, the number of days of intravenous antibiotics were reduced in all subgroups, although 72% of patients with ppFEV1<40 still experienced at least one exacerbation/year under LUMA-IVA. Comparable increase in body mass index was seen in the three subgroups. CONCLUSION:Phe508del homozygous CF patients benefit from LUMA-IVA at all levels of baseline lung function, but the characteristics and magnitude of the response vary depending on ppFEV1 at baseline.