Clinical Effectiveness of Elexacaftor/Tezacftor/Ivacaftor in People with Cystic Fibrosis.

Rationale: The cystic fibrosis (CF) modulator drug elexacaftor/tezacaftor/ivacaftor (ETI) proved highly effective in controlled clinical trials for individuals with ≥1 F508del allele, which occurs in at least 85% of people with CF (PwCF). Objective: PROMISE is a post-approval study to understand the broad effects of ETI through 30 months clinical use in a more diverse US patient population with planned analyses after 6 months. Methods: Prospective, observational study in 487 PwCF age ≥12 years with ≥1 F508del allele starting ETI for the first time. Assessments occurred before and 1, 3, and 6 months into ETI therapy. Outcomes included change in ppFEV1, sweat chloride concentration, body mass index, and self-reported respiratory symptoms. Results: average age was 25.1 years. 44.1% entered the study using tezacaftor/ivacaftor or lumacaftor/ivacaftor while 6.7% were using ivacaftor, consistent with F508del homozygosity and G551D allele, respectively. At 6 months into ETI therapy, ppFEV1 improved 9.76 percentage points (95% CI 8.76, 10.76) from baseline, CFQ-R Respiratory Domain score improved 20.4 points (95% CI 18.3, 22.5), and sweat chloride decreased -41.7 mmol/L (95% CI 43.8, 39.6). BMI also significantly increased. Changes were larger in those naïve to modulators but substantial in all groups, including those treated with ivacaftor at baseline. Conclusions: ETI by clinical prescription provided large improvements in lung function, respiratory symptoms, and BMI in a diverse population naïve to modulator drug therapy, using existing two-drug combinations, or using ivacaftor alone. Each group also experienced significant reductions in sweat chloride concentration, which correlated with improved ppFEV1 in the overall study population. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/).