Tocilizumab (trade name Actemra) is a humanized monoclonal antibody which targets the interleukin-6 receptor (IL-6R). The cytokine IL-6 mediates inflammation and immune response and therefore elevated levels of IL-6 can often be found in autoimmune/ inflammatory diseases including rheumatoid arthritis, multiple myeloma and prostate cancer. Tocilizumab is used as a treatment in these disease cases as it prevents IL-6 from binding to its receptor.

Biosimilar Characterization Considerations

The guidelines state that characterization of Tocilizumab products should include determination of physicochemical and structural properties, purity, impurities and quantity in line with ICH Topic Q6B:

Structural Characterization

Physicochemical Characterization

Product Specific Technical Considerations

Particular attention should be paid to the Post Translational Modifications (PTMs) including:

  1. N-terminal heterogeneity
  2. Disulfide bridges
  3. Heavy chain C-terminal Lysine
  4. Glycosylation (in particular galctosylation and fucosylation levels)
  5. Deamidation
  6. Oxidation