Biosimilar Filgrastim (Tevagrastim, XMO2) for Allogeneic Hematopoietic Stem Cell Mobilization and Transplantation in Patients with Acute Myelogenous Leukemia/Myelodysplastic Syndromes

Human recombinant granulocyte colony-stimulating factor (G-CSF), filgrastim (Neupogen; Amgen, Thousand Oaks, CA, USA), has been widely used for the mobilization of CD34⁺ hematopoietic stem cells (HSC) from healthy donors. The experience with biosimilar G-CSF agents in this area is limited. We performed a prospective study assessing Tevagrastim (biosimilar filgrastim, XMO2; Teva, Israel) for mobilization of CD34⁺ peripheral blood HSC in HLA-matched healthy sibling donors for transplantation in 24 patients with acute myelogenous leukemia (AML) and high-risk myelodysplastic syndromes (MDS) (NCT01542944). Results were compared to a historical control group of sibling donors who received filgrastim for stem cell mobilization for allogeneic stem cell transplantations in patients with AML and MDS. The healthy donors received Tevagrastim or filgrastim in a dose of 10 μg/kg body weight (BW) subcutaneously for 4 days. The target yields of CD34⁺ cells was 5 × 10⁶ CD34⁺ cells/kg BW of the recipient. A median 10.2 × 10⁶ (range, 2.52 to 35.4) and 9.35 × 10⁶ (range, 3.7 to 30.6) CD34⁺ cells per kg BW were collected in the Tevagrastim and filgrastim groups, respectively. All patients promptly engrafted with a median day of absolute neutrophil count (ANC) of >.5 × 10⁹/L and >1 × 10⁹/L of 13 days (range, 10 to 21) and 13.5 days (range, 10 to 22), respectively in the Tevagrastim group and 12 days (range, 10 to 18) and 13 days (range, 10 to 18) in the filgrastim group, respectively. Platelets reached counts of >20 × 10⁹/L and >50 × 10⁹/L within a median of 14 days (range, 11 to 33) and 17 days (range, 12 to 33) in the Tevagrastim group and 13 (range, 10 to 29) and 15 (range, 10 to 32) days in the filgrastim group, respectively. The donors developed only mild and transient side effects, which were not different between the Tevagrastim study group and the filgrastim historical control group. Similarly, the transplantation-related toxicities and outcomes did not differ between the patients who underwent transplantation with Tevagrastim-mobilized grafts and the filgrastim historical controls. In summary, we observed a similar yield of CD34⁺ stem cell mobilization in the Tevagrastim study group and the filgrastim historical control group with similar engraftment kinetic, hematopoietic reconstitution, and transplantation outcome. Tevagrastim administration was safe with minimal side effects and toxicity not different than historical controls. The lack of significant differences for all parameters of stem cell collection, engraftment, and safety with the biosimilar XMO2 Tevagrastim demonstrate the "similarity" of the biosimilar and recombinant human G-CSF in this indication.