Healthy volunteer stem cell donors followed up 10 years after stimulation with biosimilar filgrastim.

Background: The application of granulocyte colony-stimulating factors (G-CSF) for mobilizing hematopoietic stem and progenitor cells in healthy donors is considered safe. However, only limited safety information is available about long-term adverse events (AEs) in this setting. To determine the long-term effect of health consequences to stem cell donors, 244 G-CSF-mobilized donors were tracked prospectively for 10 years.

Study design and methods: A total of 244 adult healthy unrelated stem cell donors who received at least one dose of Sandoz biosimilar filgrastim were enrolled in this prospective long-term surveillance study. Safety, mental health, and physical health were followed up over a period of 10 years.

Results: Ninety-five percent of the donors experience at least one AE during the stem mobilization period; beyond this period, the onset of the first AE was 3.86 [3.45-4.27] years in females and 4.02 [3.68-4.35] years in males. The risk of reporting an AE was significantly lower in the youngest tertile of donors, when compared to the oldest (p = 0.026). Females were more likely to report AEs than males (0.40 vs. 0.21 AEs/year, rate ratio: 1.87 [CI: 1.32-2.64]; <0.001). No clinically relevant permanent changes occurred up to 10 years from mobilization in physical or mental health.

Discussion: No new or excessive AEs were identified during a 10-year follow-up of mobilized stem cell donors and therefore reassure about the overall safety of stem cell mobilization with G-CSF in healthy volunteers.