Longitudinal changes in lung function following initiation of lumacaftor/ivacaftor combination

The combination of lumacaftor and ivacaftor (LUM/IVA) is a recently approved CFTR modulator treatment for homozygous F508del CF patients. Our study aimed at evaluating the change in the rate of lung function decline after one-year treatment with LUM/IVA.

The study evaluated patients homozygous for F508del, 12 to 23 years old. All had been treated for one year with LUM/IVA. The collected data included the percent predicted values of FEV1 (ppFEV1) and FVC (ppFVC), and the FEV1/FVC ratio (FEV1/FVC), that corresponded to 12, 24, and 36 months prior to, and 12 months after the initiation of LUM/IVA; also, the 3 highest values of the ppFEV1 (and the corresponding ppFVC, and FEV1/FVC) for the periods 0-12 months, 12-24 months, and 24-36 months prior to as well as the 12-month period after the initiation of LUM/IVA. The baseline lung function was estimated before the commencement of the drug. Data were analyzed longitudinally with generalized estimating equations models and continuous linear splines. A single knot was used that corresponded to the time point of LUM/IVA initiation.

Fifty-two patients were analyzed. The multivariate longitudinal analysis of spirometric indices with linear splines demonstrated a significant change in the slopes of ppFEV1 and ppFVC decline, reflecting a significant improvement after the initiation of LUM/IVA treatment.

In this real-world study, lung function improved over a relatively short time period of only one year, after the commencement of LUM/IVA.