Commentary on "Reference Standard Calibration Challenges in the Case of Erythropoietin: Impact on Potency and Biosimilarity Determination".

The article provides a commentary on a recently published study in which the veracity of global/compendial Reference Standards for therapeutic recombinant human Erythropoietin (EPO) products is called into question. Here, we clarify the roles and intended uses of such standards, including the methods used in their value-assignment, and expand upon the potential causes of an apparent drift in unitage between EPO products from different geographical regions.