Baricitinib is a selective immunosuppressant, reversible inhibitor of Janus kinase 1 and 2 (JAK1 and JAK2). Janus kinases (JAKs) are enzymes that transduce intracellular signals from cellular receptors for a number of cytokines and growth factors involved in hematopoiesis, inflammation, and immune response. As part of the intracellular signaling pathway, Janus kinases phosphorylate and activate STATs (signal transporters and transcription activators), which in turn activate gene expression in the cell. Baricitinib modulates these signaling cascades by partially inhibiting JAK1 and JAK2 enzymatic activity, thereby reducing STAT phosphorylation and activation.
Indication for medical use of baricitinib, according to the instructions for medical use: treatment of moderate or severe active rheumatoid arthritis in adult patients with intolerance or lack of an adequate response to treatment with one or more basic antirheumatic drugs .
Taking into account the effect of baricitinib on the immune response by disrupting the transduction of intracellular signals from cellular receptors for a number of cytokines (IL-6) and growth factors, the presumed efficacy of baricitinib in the “cytokine storm” observed in severe COVID-19 is discussed .
1. Otdelenov V.A., Tsvetov V.M., Sychev D.A. Possibility to use barycytinib in patients with COVID-19, including for treatment of «cytokine storm». Kachestvennaya Klinicheskaya Praktika = Good Clinical Practice. 2020;(4S):11-14. (In Russ.) https://doi.org/10.37489/2588-0519-2020-S4-11-14