Background. Cystic fibrosis is a typical genetic exocrinopathy with underlying mutation of the gene that controls the structure and function of the cystic fibrosis transmembrane regulator (CFTR). The genetic variability of the CFTR gene can be associated with both a reduced amount and a complete absence of a transmembrane protein that provides the transport of electrolytes, namely chloride and sodium ions, in the cells of the exocrine glands, leading to a violation of the electrical potential of the cells, dehydration of the secretion, and changes in its viscosity. Until recently, the treatment of patients with cystic fibrosis was exclusively symptomatic; however, with the advent of targeted therapy for these patients, new prospects are opening up in terms of duration and quality of life. In the Russian Federation, targeted therapy for patients with cystic fibrosis has become available since the beginning of 2021, when the drug ivacaftor/ lumacaftor (Orkambi) was registered in our country. This article describes the experience of 12-week use of ivacaftor/lumacaftor in 3 children with cystic fibrosis in the Astrakhan region.
Methods. The pre-start diagnostic protocol included measurement of sweat fluid chlorides, assessment of external respiration function, determination of body mass index, biochemical blood test parameters, and pancreatic elastase levels. Monitoring of these indicators was carried out at the decreed time: on the 14th day, 4 and 12 weeks after the start of therapy.
Results. Against the background of the therapy, two patients showed an improvement in the parameters of the external respiration function and a decrease in the level of sweat fluid chlorides. In the third patient, adverse events against the background of the use of ivacaftor/lumacaftor in the form of an increase in the level of hepatic transaminases were noted, which was an indication for discontinu- ation of therapy.
Conclusion. The study showed the mixed results of ivacaftor/lumacaftor therapy. On the one hand, there are favorable prospects for influencing the course and prognosis of the disease by normalizing the work of the chloride channel and improving the clinical status of patients; on the other hand, the development of serious adverse events may lead to the rejection of the chosen therapy. All of the above indicates the need to increase the duration of follow-up with the involvement of new patients for objectification and evaluation of long-term results.

Keywords: lumacaftor, ivacaftor, targeted therapy, cystic fibrosis