Comparison of the physicochemical properties of a biosimilar filgrastim with those of reference filgrastim.

Recombinant human granulocyte-colony stimulating factor (filgrastim) is a therapeutic protein used primarily to reduce incidence and duration of severe neutropenia and its associated, and serious, complications. We have developed a biosimilar filgrastim (Hospira filgrastim; Nivestim) designed to be comparable to Amgen filgrastim (Neupogen). An extensive characterization study assessed the physiochemical similarity of Hospira filgrastim to Amgen filgrastim. Both drugs were supplied in 1 ml glass, single-use, prefilled syringes (five batches of each product at 480 microg/0.5 ml and one batch of each product at 300 microg/0.5 ml). Samples were evaluated using state-of-the-art analytical methods (validated in accordance with International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use or Pharmeuropa guidelines) to determine physicochemical properties, molecular characteristics, purity and biological activity. Samples were compared after long-term storage at 2-8 degrees C and storage at 40 degrees C (stress conditions) to evaluate their degradation impurity profiles. Hospira filgrastim and Amgen filgrastim were shown to have similar physicochemical properties, molecular characteristics, purity and biological activity. No significant differences in product-related impurities were recorded between Hospira filgrastim and Amgen filgrastim following storage for 12 weeks under stress conditions. These data show that the physicochemical profile of Hospira filgrastim is similar to that of Amgen filgrastim.