The first World Health Organization International Standard for in vitro biological activity of darbepoetin

The expiry of patents protecting the manufacture and sale of therapeutic darbepoetin products is expected to lead to the emergence of biosimilar products. In response to this, the first World Health Organization (WHO) International Standard (IS) for darbepoetin has been developed. A lyophilized preparation of darbepoetin, coded 17/204, was evaluated in an international collaborative study, the results of which suggest that the candidate preparation is suitable to serve as an IS. This material defines the International Unit (IU) of in vitro biological activity of darbepoetin and should be used to calibrate of in vitro potency assays of darbepoetin preparations. It is envisaged that widespread use of the IS will promote the consistency and harmonization of darbepoetin in vitro bioassay measurements in laboratories worldwide. Each ampoule contains 100,000 IU of darbepoetin activity. The IU is not intended to revise product labelling or dosing requirements, decisions regarding which lie solely with the regulatory authority. Additionally, the IS is not intended to define the specific activity of darbepoetin, as this may differ between products in the future. Finally, the IS is not intended to serve any regulatory role in defining biosimilarity (i.e. as a reference medicinal product).