Real-life acute lung function changes after lumacaftor/ivacaftor first administration in pediatric patients with cystic fibrosis

The combination of lumacaftor and ivacaftor (LUM/IVA) has been reported to induce a mean acute absolute drop of − 4.1% predicted forced expiratory volume in 1 s (FEV1) after a unique administration in healthy subjects. The aim of the present study was to assess acute FEV1 changes after the first dose of LUM/IVA in CF patients. A total of 32 pediatric patients were included. Respiratory manifestations occurred in only 3 patients (9.4%), but FEV1 consistently decreased (− 10.4 ± 4.6%, range: − 1.5; − 21.8%). FEV1 only partially resumed after salbutamol inhalation. Patients with previously known significant reversible airway obstruction and low FEV1 were more at risk of FEV1 decrease.