Sarilumab is a monoclonal antibody used in the treatment of autoimmune diseases, specifically rheumatoid arthritis. Sarilumab targets and inhibits the interleukin-6 receptor (IL-6R), which is involved in the inflammatory pathway that contributes to autoimmune diseases like rheumatoid arthritis. By blocking IL-6R, sarilumab helps to reduce inflammation and alleviate symptoms associated with rheumatoid arthritis. It is indicated for the treatment of moderate to severe rheumatoid arthritis in adult patients who have not responded adequately to conventional disease-modifying antirheumatic drugs (DMARDs) such as methotrexate. Sarilumab is often used in combination with methotrexate or as monotherapy.