Contribution of the intestinal current measurement method to assessment of the efficacy of CFTR modulators in cystic fibrosis

Cystic fibrosis (CF) is a disease caused by pathogenic variants of the CFTR gene. In the last decade, the treatment algorithm has entered a new era as several drugs have become available that restore the function of the CFTR chloride channel and are called CFTR modulators. The efficacy and safety of targeted drugs in cystic fibrosis needs to be further investigated using additional assessment methods. The aim of this study was to investigate the role of intestinal current measurement (ICM) in assessing the efficacy of targeted therapy for cystic fibrosis. Methods. The efficacy of CFTR modulator therapy was evaluated in 15 patients, of which 10 were children and 5 were adults. In addition to the ICM method, patients’ clinical parameters, sweat test, and pulmonary function were also evaluated according to clinical guidelines. Results. Patients with genotypes 2143delT/7121G>T and G542X/R785X had no restoration of chloride channel function with elexacaftor + tezacaftor + ivacaftor therapy, and patients with the L467F;F508del genotype with lumacaftor + ivacaftor therapy. In patients with the F508del/F508del, N1303K/G461E, N1303K/3321delG genotype, improvements were noted in terms of the restoration of CFTR channel function during therapy with elexacaftor + tezacaftor + ivacaftor therapy, and in patients with the F508del/F508del genotype during therapy with tezacaftor + ivacaftor therapy and lumacaftor + ivacaftor. Conclusion. Restoring the function of the epithelial chloride channel (CFTR) is the basis for increasing life expectancy in CF. The crucial role of the ICM method in determining the efficacy of CFTR modulators is shown.