Levilimab (also known as BCD-089) is a human monoclonal antibody that functions as an inhibitor of the interleukin-6 receptor (IL-6R). By binding to both soluble and membrane-bound forms of IL-6R, it blocks the interaction between the receptor and its cytokine, interleukin-6 (IL-6). This inhibition prevents downstream pro-inflammatory signaling through the JAK/STAT pathway, thereby reducing the cytokine storm and systemic inflammation. It is approved in Russia for the treatment of moderate-to-severe COVID-19 pneumonia in adults, specifically for those requiring supplemental oxygen, and has also been investigated for autoimmune conditions such as rheumatoid arthritis.