Comparison of CD34(+) cell mobilization, blood graft cellular composition, and post-transplant outcome in myeloma patients mobilized with filgrastim or pegfilgrastim added to low-dose cyclophosphamide: A prospective multicenter study

Background Scarce data exist on the impact of granulocyte-colony stimulating factor (G-CSF) type on the mobilizing capacity of CD34(+) cells, graft cellular composition, and outcome in myeloma (MM) patients. Patients and Methods In this prospective multicenter study, 70 patients with MM received filgrastim (FIL) and 20 patients received pegfilgrastim (PEG) as a G-CSF after low-dose cyclophosphamide. Flow cytometry was used to analyze the mobilization of CD34(+) cells and cellular composition of blood grafts, hematologic recovery, and survival after auto-SCT according to the G-CSF choice. Results The CD34(+) cell yield of the first apheresis was higher in the FIL group (5.3 vs. 4.2 x 10(6)/kg, p = .025). The better mobilizing capacity was observed in the FIL group especially after bortezomib-based induction based on the higher first apheresis yield of CD34(+) cells (7.5 vs. 4.4 x 10(6)/kg, p = .001). The median CD19(+) cell count (1.0 vs. 0.4 x 10(6)/kg, p = .010) and the number of CD3(+) T lymphocytes (43.1 vs. 31.8 x 10(6)/kg, p = .122) in the infused graft were higher in the patients mobilized with FIL. Both early (day +15) (56 vs. 108 x 10(9)/L, p = .002) and later platelet recovery at 6 months (191 vs. 226 x 10(9)/L, p = .026) were faster in the PEG group. Conclusion G-CSF type seems to impact on the mobilization capacity and cellular composition of infused graft and also platelet recovery post-transplant. A randomized study might be warranted to verify the effects of G-CSF choice in the mobilization field.