Biochemical and Biological Quality Control of Two Recombinant Human Erythropoietin Biosimilar Products

Background: The control of structural variations of therapeutic proteins is a big challenge requiring sophistic and accurate analytical tools for the analysis of the conformational stability of the final formulations. Methods: This paper reports the biochemical, structural and biological tests used to evaluate the identity and purity of a recombinant human erythropoietin alfa, used in the formulation of the first Tunisian approved biosimilar (Epomax 2000 I.U/mL) and the comparative assessment between this final product and an equivalent commercialized biosimilar in Tunisia with respect to the protein content, physiochemical integrity, immunogenicity and biological activity. Results: Our results demonstrated that Epomax showed high and similar consistence in total protein content (2.605 mg/mL for Bradford assay), isotonicity (271 mOsm/kg for Osmolarity measurement), purity (a single band at 37.40 kDa for western blot analysis), and potency (1724.00 I.U./mL for in vivo bioassay) when compared to the commercialized biosimilar product (2.969 mg/mL for Bradford assay, 291 mOsm/kg for Osmolarity measurement, a single band at 36.29 kDa and 1690.79 I.U./mL for in vivo bioassay). Conclusion: The analyzed erythropoietin raw material is highly pure and in compliance with the specifications of the European Pharmacopeia. As well as, the final product Epomax has shown highly comparability with the commercialized reference product.