Use of the G-CSF Biosimilar Ratiograstim® to Mobilize Peripheral Stem Cells in Healthy Donors for Allogeneic Stem Cell Transplantation

There is limited experience in the application of the biosimilar Ratiograstim^® for mobilization of peripheral stem cells and especially in healthy donors (HD). The G-CSF biosimilar Ratiograstim^® was approved by the EMA for mobilization of peripheral stem cells. Here, we investigated on two cohorts the efficacy and safety of peripheral stem cell mobilization by either the biosimilar or the reference G-CSF.

MATERIAL AND METHODS: 22 patients and their related donors were investigated for: 1. leukocyte-count in the peripheral blood of healthy donors, 2. number of collected CD34⁺ stem cells, 3. number of apheresis procedures, 4. CD34⁺ cell count per kg body weight of the patients, 5. time till regeneration, 6. side effects.

In HD receiving subcutaneously Ratiograstim^®, WBC counts in the peripheral blood ranged from 29.9 G/L to 64.6 G/L (mean 48.9 G/L) and the CD34 cell counts from 19.3/μl to 114.6/μl (mean 67.6/μl). In a mean of 1.45 apheresis procedures 172.5×10⁶ up to 494×10⁶ CD34⁺ cells (mean 354.7×10⁶) were collected. This resulted in CD34⁺ cell numbers of 2.28×10⁶ up to 1×10⁷ (mean 5.17×10⁶) per kg body weight of the patients. In HD receiving subcutaneously the reference G-CSF, WBC counts ranged from 27.1 G/L up to 62.5 G/L (mean 43.3 G/L) and the CD34⁺ cell counts from 13.55/μl up to 122.4/μl (mean 57.3/μl). A mean of 1.27 apheresis procedures were necessary to collect 181.74×10⁶ up to 598.00×10⁶ CD34⁺ cells (mean 370.49×10⁶) absolutely. This translates into 2.33×10⁶ up to 7.9×10⁶ (mean 4.95×10⁶) CD34⁺ cells per kg body weight of the patients. Patients regenerated >0.5 G/L neutrophils/μl within 15 days in the Ratiograstim^® cohort versus 17 days in the reference group.

In total we analyzed two cohorts, one cohort of 22 patients and donors receiving the biosimilar Ratiograstim^® versus another cohort receiving reference G-CSF. No unexpected side effects and no increased frequencies in side effects as flu-like symptoms, allergic reactions and alterations in kidney and liver function were observed. In comparison to the reference group we did not see significant differences in 1. WBC count in the peripheral blood after mobilisation, 2. CD34⁺ cell count after mobilisation, 3. CD34⁺ cell count absolute numbers, 4. CD34⁺ cells per kg body weight of the patients, 5. engraftment, 6. regeneration of WBC, neutrophils and platelets. All patients engrafted. Therefore, the efficacy of the biosimilar Ratiograstim^® when compared to the reference G-CSF was comparable in our cohort of patients in the context of allogeneic stem cell transplantation.

Schmitt:ratiopharm: Honoraria, Research Funding. Freund:Medac: Honoraria, Research Funding.