Background: In two pivotal phase 3 trials, up to 24 weeks of treatment with elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) was efficacious and safe in patients with cystic fibrosis (CF) ≥12 years of age who have at least oneF508delallele. The aim of this study is to assess long-term safety and efficacy of ELX/TEZ/IVA in these patients.Methods: In this phase 3, open-label, single-arm extension study, participants withF508del–minimal function (from a 24-week parent study; n=399) orF508del–F508del(from a 4-week parent study; n=107) genotypes receive ELX/TEZ/IVA at the same dose (ELX 200 mg once daily, TEZ 100 mg once daily and IVA 150 mg every 12 h). The primary end-point is safety and tolerability. A prespecified interim analysis was conducted when the last participant reached the Week 144 visit.Results: At the Week 144 interim analysis, mean duration of exposure to ELX/TEZ/IVA in the extension study was 151.1 weeks. Exposure-adjusted rates of adverse events (AEs) (586.6 events per 100 participant-years) and serious AEs (22.4 events per 100 participant-years) were lower than in the ELX/TEZ/IVA treatment group in the 24-week parent study (1096.0 and 36.9 events per 100 participant-years, respectively); most participants had AEs classified as mild (16.4% of participants) or moderate (60.3% of participants) in severity. 14 participants (2.8%) had AEs that led to treatment discontinuation. Following initiation of ELX/TEZ/IVA, participants had increases in forced expiratory volume in 1 s (FEV₁) percentage predicted, Cystic Fibrosis Questionnaire-Revised respiratory domain score and body mass index, and had decreases in sweat chloride concentration and pulmonary exacerbation rates that were maintained over the interim analysis period. The mean annualised rate of change in FEV₁% pred was +0.07 (95% CI −0.12–0.26) percentage points among the participants.Conclusions: ELX/TEZ/IVA was generally safe and well tolerated, with a safety profile consistent with the 24-week parent study. Participants had sustained improvements in lung function, respiratory symptoms, CF transmembrane conductance regulator function, pulmonary exacerbation rates and nutritional status. These results support the favourable safety profile and durable, disease-modifying clinical benefits of ELX/TEZ/IVA.

Elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) was shown to be safe and efficacious in people with cystic fibrosis (CF) with ≥ 1 F508del-CFTR allele in Phase 3 clinical trials. ELX/TEZ/IVA treatment led to improved lung function, with increases in percent predicted forced expiratory volume in 1 second (ppFEV₁) and Cystic Fibrosis Questionnaire-Revised respiratory domain score. Here, we evaluated the impact of ELX/TEZ/IVA on the rate of lung function decline over time by comparing changes in ppFEV₁ in participants from the Phase 3 trials with a matched group of people with CF from the US Cystic Fibrosis Foundation Patient Registry not eligible for cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapy. Participants treated with ELX/TEZ/IVA had on average no loss of pulmonary function over a 2-year period (mean annualized rate of change in ppFEV₁, +0.39 percentage points [95% CI, -0.06 to 0.85]) compared with a 1.92 percentage point annual decline (95% CI, -2.16 to -1.69) in ppFEV₁ in untreated controls. ELX/TEZ/IVA is the first CFTR modulator therapy shown to halt lung function decline over an extended time period.

Rationale: Clinical and real-world studies show that elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) is efficacious and safe in people with cystic fibrosis (CF) ≥12 years of age with at least one F508del allele. Objectives: Given the potential for lifelong ELX/TEZ/IVA use, the long-term safety and efficacy of ELX/TEZ/IVA was assessed. Methods: In this phase 3, open-label, single-arm extension study, participants with F508del-minimal function genotypes (from 24-wk parent study 445-102 [n = 399]) or with the F508del-F508del genotype (from 4-wk parent study 445-103 [n = 107]) received ELX/TEZ/IVA (ELX 200 mg once daily, TEZ 100 mg once daily, and IVA 150 mg every 12 h) over 192 weeks. Measurements and Main Results: The primary endpoint was safety and tolerability. Mean exposure to ELX/TEZ/IVA was 172.6 weeks. Most participants had adverse events classified as mild (12.8%) or moderate (60.7%) in severity. Eighteen participants (3.6%) had adverse events that led to treatment discontinuation. After starting ELX/TEZ/IVA, participants had consistent increases in percent predicted FEV1 (ppFEV1), Cystic Fibrosis Questionnaire–Revised respiratory domain score, and body mass index, with decreases in sweat chloride concentration and pulmonary exacerbation rates; these improvements were maintained through 192 weeks. The mean annualized rate of change in ppFEV1 was 0.02 percentage points (95% confidence interval, −0.14 to 0.19) after initiation of ELX/TEZ/IVA. Conclusions: During this 192-week open-label extension study, the longest clinical study of a CFTR (cystic fibrosis transmembrane conductance regulator) modulator to date, ELX/TEZ/IVA remained generally safe and well tolerated. Participants had sustained improvements in lung function, respiratory symptoms, CFTR function, pulmonary exacerbation rates, and nutritional status. The estimated annualized rate of change in ppFEV1 suggests no evidence of pulmonary function loss across the study population over the 4-year treatment period. These results confirm the favorable long-term safety profile and durable disease-modifying clinical benefits of ELX/TEZ/IVA in adolescents and adults with CF. Clinical trial registered with www.clinicaltrials.gov (NCT03525574).

Cystic fibrosis (CF) lung disease begins early in childhood and is characterized by neutrophilic inflammation of the airways. Neutrophil extracellular traps (NETs) represent one mechanism by which neutrophils contribute to lung damage. The enzyme peptidylarginine deiminase 4 (PAD4) is required for NET formation. Our overall concept is that NET formation delivers PAD4 outside the neutrophil resulting in autoantibody generation, and this autoimmunity may be a novel mechanism contributing to CF lung disease progression. The aim of this study was to investigate clinical predictors of serum anti-PAD4 autoantibody (PAD4 Ab) levels in CF subjects with a wide range of ages from early childhood through middle age. We measured PAD4 Ab levels in sera from 104 CF subjects. PAD4 Abs were detectable among CF children as young as one year of age and elevated compared to paediatric healthy controls. PAD4 Ab levels increased significantly with age (r = 0.584, p <.001) and correlated with lower lung function (r = −0.481, n = 99, p <.001). PAD4 Abs were elevated in subjects with chronic Pseudomonas aeruginosa airways infection (p <.001), but not with other key clinical CF co-variates including sex, CFTR genotype, sweat chloride, pancreatic enzyme use, nutritional status, recent pulmonary exacerbations, Staphylococcus aureus, or CF-related diabetes. PAD4 Ab levels were also correlated with serum anti-double-stranded DNA IgA autoantibodies, which have similarly been shown to be elevated in CF subjects and associated with lung damage. In multivariable analysis, age and lung function remained correlated with PAD4 Ab levels. In summary, we describe novel findings of anti-PAD4 autoantibodies in CF that are present early in childhood, increase over time with age, and correlate with lung disease severity. Autoimmunity to antigens extruded by NETs appears to be an early event in CF lung disease, and airway autoimmunity related to NET formation is a potential mechanism of lung disease progression in CF.

Advance care planning (ACP) is recommended for people with cystic fibrosis (CF), yet guidance for optimal implementation is lacking. To assess ACP-related thoughts, comfort level, and preferences among people with CF to guide evidence-based routine implementation of ACP in the CF clinic. A cross-sectional survey assessed ACP-related experiences and preferences. Thirty-eight adolescents and adults with CF from an urban CF center. Few subjects reported talking to their CF team about ACP care preferences (5%) or completing advance directives detailing desired medical treatments (11%). However, most participants worried about living with advanced disease (84%) and felt comfortable discussing ACP preferences with CF providers (92%). Subjects largely preferred that ACP conversations occur when they are generally healthy, in the outpatient setting, and with any familiar CF team member. Disease severity was not associated with frequency of worry about living with advanced disease, comfort level with ACP discussions, or ACP setting preferences. People with CF worry about advanced disease and feel comfortable discussing ACP, but need more guidance to understand and document ACP choices. CF patient experiences and preferences support implementation of an early, active approach to ACP for people with CF.