ABSTRACT

Baricitinib is an oral Janus kinase (JAK) inhibitor and a member of targeted-synthetic disease-modifying anti-rheumatic drugs. Baricitinib competitively binds to the adenosine triphosphate and inhibits the synthesis of cytokines, which play prominent roles in rheumatoid arthritis (RA) pathogenesis by selectively inhibiting JAK1 and JAK2 at an effective dose. Its bioavailability is approximately 80%, and 64% is excreted via the kidney. To evaluate the efficacy and safety of baricitinib, 19 clinical pharmacological studies and 3 phase II, 4 phase III, and one extension study were conducted in patients with RA, and the effectiveness of baricitinib has been shown in these studies. Clinical research and real-world data suggest that baricitinib is a safe drug, but it has some well-known side effects such as neutropenia, anemia, elevation of transaminase levels, hyperlipidemia, and increased risk of infections. In these studies, major cardiovascular events were found to be similar in frequency to placebo, and the incidence of malignancy was found to be similar to the age-related cancer incidence in the general population. However, as is the case with other JAK inhibitors, it is recommended to be used with caution in patients with risk factors for deep vein thrombosis such as advanced age, obesity, and inactivity.

Keywords: Janus kinase, baricitinib, rheumatoid arthritis, disease-modifying anti-rheumatic drug