Eculizumab (trade name Soliris) is a human monoclonal antibody that binds to the complement C5 protein, thereby blocking prothrombotic and pro‑inflammatory processes. It is currently used to treat atypical Haemolytic Uraemic Syndrome (aHUS), a rare disease causing inflammation of blood vessels and the formation of blood clots.

Biosimilar Characterization Considerations

The guidelines state that characterization of Eculizumab 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