tocilizumab + azathioprine

**Tocilizumab + azathioprine** is a combination regimen of two immunosuppressive drugs, often used sequentially or in combination during transitions, but not as a fixed-dose combination product. **Tocilizumab** is a humanized monoclonal antibody that binds to both soluble and membrane-bound interleukin-6 (IL-6) receptors, inhibiting IL-6-mediated signaling implicated in autoimmune inflammatory processes such as neuromyelitis optica spectrum disorder (NMOSD) and rheumatoid arthritis. **Azathioprine** is an immunosuppressive antimetabolite that inhibits purine synthesis, primarily affecting proliferation of B and T lymphocytes. Both agents are used to prevent relapses in conditions like NMOSD, with trials showing better relapse prevention with tocilizumab compared to azathioprine monotherapy[1][2][3][4].