This is a humanized IgG1 monoclonal antibody using the same sequences as the therapeutic antibody tocilizumab. It functions as an IL6 receptor antagonist for the treatment of inflammatory and autoimmune conditions. Tocilizumab is indicated for moderate to severe rheumatoid arthritis, giant cell arteritis, systemic sclerosis-associated interstitial lung disease, polyarticular juvenile idiopathic arthritis, systemic juvenile idiopathic arthritis, and cytokine release syndrome. Additionally, it is employed in adults who are receiving systemic corticosteroids and require supplemental oxygen, mechanical ventilation, or extracorporeal membrane oxygenation (ECMO) for COVID-19 treatment. Tocilizumab binds both soluble and membrane-bound IL6 receptros to impede the pro-inflammatory effects of IL6. It has been noted that the membrane-bound form and soluble form of the IL6 receptors may have different effects in the pathogenesis of rheumatoid arthritis, with the soluble form being more implicated in disease progression. Tocilizumab exhibits a prolonged duration of action with administration typically every 4 weeks and has a wide therapeutic index.