Change in exercise capacity measured by Cardio-pulmonary Exercise Testing (CPET) in Danish people with cystic fibrosis after initiation of treatment with Lumacaftor/Ivacaftor and Tezacaftor/Ivacaftor.

Background: Since 2015, when the first cystic fibrosis transmembrane conductance regulator (CFTR) modulators were approved for people with cystic fibrosis (CF) homozygous for F508del-CFTR, studies have shown improved lung function after initiation of the treatment and patients experience improved physical capacity. The aim of this study was to investigate change in exercise capacity after initiation of Lumacaftor/Ivacaftor and Tezacaftor/Ivacaftor treatment (LUM/IVA, TEZ/IVA).

Methods: We performed a single group prospective observational cohort study with follow-up at six and 12 months. The study examined change in exercise capacity in people with CF initiating treatment with LUM/IVA and TEZ/IVA, measured by cardio-pulmonary exercise testing (CPET). Inclusion criteria were people with CF homozygous for F508del-CFTR aged 12 years or older eligible for LUM/IVA and TEZ/IVA treatment from June 2017 until June 2019. Primary outcomes were change in VO and maximal workload. Secondary outcomes were change in muscle strength, muscle power and body composition in a subgroup of the study population.

Results: A total of 91 patients were included in the analysis. The mean change in VO and VO divided by body weight from baseline to 12-months follow-up was 145.7 (91.2;200.2) ml/min and 1.07 (95% CI 0.19;1.95) ml/min/kg, respectively. The mean change in maximal workload between baseline and 12 months was 14.2 Watt (95% CI 9.1;19.2). All improvements in exercise capacity were statistically significant.

Conclusions: Patients in this study improved their exercise capacity by a statistically significant increase in VO and maximal workload 12 months after initiation of treatment with LUM/IVA and TEZ/IVA.