Background. Chronic lymphocytic leukemia (CLL) is the most common type of leukemia. Annual incidence rate of CLL is 2 to 6 per 100000 population. CLL is currently a disease which leads to significant social and financial costs. CLL remains an incurable disease up to this date. However, at the moment there is a bunch of drugs available on the pharmaceutical market, which can substantially elongate progression-free survival, increase duration, and improve the patients’ quality of life. One of such drugs is obinutuzumab. Positive evaluation findings of economic feasibility of using obinutuzumab in elderly patients with CLL have been received in some countries of the European Union, but under the conditions of healthcare of Ukraine pharmacoeconomic analysis of obinutuzumab use in the treatment of CLL has not been performed.
 The purpose of the work is to determine economic feasibility of using obinutuzumab (Gazyva® drug) under the conditions of healthcare system of Ukraine for the treatment of chronic lymphocytic leukemia in patients who did not receive treatment earlier.
 Materials and methods. An analysis using the Markov analysis model was performed, and it allowed the comparison between life years gained (LYG) and quality adjusted life years (QALY) to be made, which can be obtained when using alternative regimens (O+Clb or R+Clb) and expenditures on these regiments in treating patients with CLL. The analysis modelling was performed on the basis of the results of international randomized multicenter open phase III clinical trial of CLL11.
 Results. The results of Markov modelling have shown that O+Clb treatment regimen, which consists of obinutuzumab and chlorambucil, provides every patient with CLL with additional 0,1 LYG on average over a period of three years compared to R+Clb regimen. The average lifespan of the patients in whom the disease did not progress was higher in O+Clb group than in R+Clb group by more than a year – 51,2 and 38,1 months respectively. O+Clb regimen not only increases lifespan, but also improves life quality. The patients of R+Clb group have additional 0,14 QALY during the analyzed period compared to O+Clb group. The calculation of expenses on CLL treatment with consideration for time horizon of 3 years has shown that using obinutuzumab in the first line of treatment was almost twice as expensive as the alternative first-line regimen, provided that original pharmaceutical drugs were used. At the same time, due to the greater effectiveness, the high cost of the regimen with obinutuzumab is compensated by reduction in expenses on the second line of chemotherapy. The cost saving on the second line covers the cost difference of the first line of therapy when using obinutuzumab. When using original, as well as generic chemotherapeutic drugs, O+Clb (obinutuzumab + chlorambucil) regimen as a first-line therapy of patients with CLL provides the higher level of effectiveness at smaller cost. Conclusions. The available data of randomized control trials to this date are indicative of high clinical effectiveness of first-line therapy with the use of obinutuzumab + chlorambucil regimen in the patients with CLL. This regimen allows progression-free survival to be substantially elongated. It also increases the number of life years gained and improves the quality of life. Markov modelling shows that obinutuzumab + chlorambucil regimen compared to rituximab + chlorambucil regimen requires bigger expenses as a first-line therapy of the patients with CLL. At the same time, due to the greater effectiveness and longer progression-free survival, this regimen allows the amount of expenses on the next lines of therapy in the patients with CLL to be reduced, consequently total expenses on the treatment of the patients with CLL are also reduced. Pharmacoeconomic analysis based on the Markov analysis model and calculations by the «cost-effectiveness» and «cost-utility» methods allow obinutuzumab + chlorambucil regimen to be considered dominant in comparison with rituximab + chlorambucil regimen as a first-line therapy of the patients with CLL (provided that original pharmaceutical drugs are used).