The explanation of the mechanisms underlying the pathogenesis of rheumatoid arthritis (RA), along with the development of a wide range of genetically engineered biological disease-modifying anti-rheumatic drugs (bDMARDs), is among the major achievements of medicine in the 21st century. A new direction in the pharmacotherapy of inflammatory rheumatic diseases is associated with the development of “targeted” oral anti-inflammatory drugs, which include Janus kinase (JAK) inhibitors. One representative of the class of JAK inhibitors is upadacitinib (UPA), which has been registered for the treatment of RA and is undergoing clinical studies in patients with ankylosing spondylitis, psoriatic arthritis, and other inflammatory rheumatic diseases. This review presents new data on the efficacy and safety of UPA in RA. © 2020 Ima-Press Publishing House. All rights reserved.