Rituximab (trade names Rituxan/ MabThera) is a chimeric monoclonal antibody made up of murine variable regions and a human IgG1 conserved region. It is targeted against CD20, a protein found mainly on the surface of B cells and will therefore destroy these cells. For this reason, Rituximab is used to treat diseases with high or unusual B cell populations, such as lymphomas, leukemias, transplant rejection, and autoimmune disorders.

Biosimilar Characterization Considerations

The guidelines state that characterization of Rituximab 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. Levels of Pyroglutamination of the light and heavy chains
  2. Disulfide bridges
  3. Heavy chain C-terminal Lysine
  4. Glycosylation (in particular galctosylation and fucosylation levels)
  5. Deamidation
  6. Oxidation