Comparison of biosimilar filgrastim and originator filgrastim for peripheral blood stem cell mobilization for allogeneic hematopoietic stem cell transplantation

Background: Nivestym, a biosimilar granulocyte colony-stimulating factor (G-CSF) to the originator filgrastim (Neupogen), is now being used for the mobilization of peripheral blood stem cells (PBSC) in allogeneic hematopoietic stem cell transplantation (allo-HSCT). We aim to compare the efficacy of Nivestym and Neupogen for PBSC mobilization in healthy allogeneic donors. Methods: We conducted a retrospective single-center study including 541 adult allo-HSCT donors receiving Nivestym (January 2013–July 2020), or Neupogen (July 2020–June 2023) for donor PBSC mobilization. Bivariate analysis was conducted using SPSS version 28. Statistical significance was determined at a p-value <.05. Results: Our study included 541 allo-HSCT donors who received Neupogen (n = 345, 64%) or Nivestym (n = 196, 36%) for PBSC mobilization. The median age was 47 years (range 17–76). The median donor weight was 86 kg (95% confidence interval [CI]: 87–91). Donors receiving Neupogen had similar pre-G-CSF white blood cell count, CD34⁺ percentages, and circulating CD34⁺ count compared with donors receiving Nivestym. The Neupogen group had similar median PBSC product total neutrophil count, CD34⁺ percentage, absolute CD34⁺ count, and infused CD34⁺ dose compared with the Nivestym group. For donors aged 35 years or younger, the median CD34⁺ dose was higher in donors who received Neupogen compared with Nivestym (6.9 vs. 6.3 million cells/kg, p =.044). Conclusions: Nivestym demonstrated similar efficacy for PBSC mobilization compared with Neupogen among allo-HSCT donors. In donors aged 35 years or younger, a slightly lower PBSC product CD34⁺ count was noted with Nivestym compared with Neupogen.