Physicochemical and biologic comparability of a biosimilar granulocyte colony-stimulating factor with its reference product.

Background: Development of biosimilars requires physicochemical and biologic characterization to show comparability with a reference product. Zarzio (filgrastim) is a biosimilar recombinant human granulocyte colony-stimulating factor (G-CSF) that has been approved in the EU using Neupogen as its reference product.

Objective: The aim of this study was to compare the drug identity, purity, and bioactivity of Zarzio (300 and 480 μg/0.