The discovery of the JAK2V617F mutation was the beginning of a new era in the study of myeloproliferative neoplasms (MPN). In addition to contributing to the understanding of the pathophysiology of Ph-negative MPN, JAK2 mutation has become a new therapeutic target in their treatment. In treatment of PV a new era began the era of targeted therapy, which gave a hope for better treatment outcomes and improved quality of life for patients who are resistant to standard therapy. This work presents literature data on molecular-genetic features of the pathogenesis of polycythemia vera (PV) and new possibilities in the treatment of this disease, literature review about JAKinhibitors, targeted therapy of PV. There are reviewed issues on resistance and intolerance of hydroxycarbamide and interferon (IFN-a) and the definition of the indications for administration of JAK-inhibitors. There are presented data on the efficacy and safety of ruxolitinib, which were proven within the clinical trial RESPONSE.