Drug class: Interleukin-6 (IL-6) receptor antagonist; monoclonal antibody (1) Mechanism of Action Tocilizumab binds to both soluble and membrane-bound interleukin-6 receptors (sIL-6R and mIL-6R), thereby blocking IL-6 signaling. IL-6 is a pro-inflammatory cytokine produced by immune and other cells, including T cells, B cells, monocytes, and fibroblasts. By inhibiting IL-6 receptor-mediated signaling, tocilizumab reduces downstream inflammatory responses involved in immune-ce