Tocilizumab (namely MRA), a humanized anti-
interleukin (IL)-6 receptor
monoclonal antibody, is under development by Roche for the treatment of inflammatory
autoimmune diseases such as
rheumatoid arthritis (RA), systemic onset
juvenile idiopathic arthritis (JIA),
adult-onset Still's disease,
Castleman's disease and
Crohn's disease.
Tocilizumab has a long plasma half-life, so it can be administered intravenously biweekly or monthly. Phase I and II clinical trials showed that
tocilizumab (2, 4, 5, 8 or 10 mg/kg) reduced disease activity significantly in a dose-dependent manner.
Tocilizumab not only improved signs and symptoms, but also normalized inflammatory markers such as
C-reactive protein, erythrocyte sedimentation rate (ESR),
fibrinogen and
serum amyloid A, and reversed joint damage of RA. The efficacy of
tocilizumab in the treatment of RA was at least as good as
methotrexate.
Tocilizumab was generally safe and well tolerated. Some adverse events such as significant rises in total
cholesterol and
triglyceride levels, liver function disorders, decreases in white blood cell counts, diarrhoea and
infection were observed. In summary, preliminary clinical results suggest that
tocilizumab is effective and generally well tolerated in the treatment of IL-6-related inflammatory
autoimmune diseases. Like other anti-
cytokine immunotherapies, caution and close monitoring for the adverse events, especially
infection, are necessary in subsequent clinical trials.