Evaluation of a Biosimilar Granulocyte Colony-stimulating Factor for Peripheral Blood Stem Cell Mobilization in Japanese Healthy Donors: a Prospective Study

A "biosimilar" is a biotechnological product with a lower cost profile and equivalent efficacy and safety to the originator, but post-marketing clinical evaluation of biosimilar products has not been adequately conducted. We prospectively investigated the utility of biosimilar filgrastim in 13 peripheral blood stem cell (PBSC) donors from June 2014 to January 2017. In addition, we retrospectively compared these to another 13 PBSC donors mobilized with the originator filgrastim in the same period. Donor characteristics were equivalent between the groups. The median number of CD34 cells per donor body weight (BW) and blood volume processed (BV) were 4.87 × 10/kg and 25.5 × 10/mL in the biosimilar group and 4.93 × 10/kg and 16.6 × 10/mL in the originator group, respectively. There were no significant differences between the groups in the number of CD34 cells per donor BW or BV. All adverse events associated with G-CSF were permissive. The total G-CSF cost was significantly lower in the biosimilar group than in the originator group. These findings suggest that biosimilar filgrastim has the same efficacy and short-term safety as originator filgrastim for PBSC mobilization in healthy donors, with economic superiority. Longer follow-up studies are needed to evaluate the incidence of long-term adverse events.