Filgrastim-alone versus pegylated filgrastim-alone for autologous peripheral blood stem cells mobilization in newly diagnosed multiple myeloma patients.

BACKGROUND: Autologous hematopoietic stem cell transplantation (aHSCT) is the recommended standard upfront treatment for transplant eligible myeloma patients. Considering possible complications related to chemotherapy-cytokine mobilization, cytokine-alone mobilization is often used. We compared mobilization with filgrastim alone to pegfilgrastim alone in newly diagnosed myeloma patients after induction treatment with bortezomib and dexamethasone. The comparison was made between peripheral blood stem cell (PBSC) yields, number of apheresis, hematopoietic stem cell subsets, and time to neutrophil and platelet engraftment after aHSCT.

METHODS: A total of 42 myeloma patients were prospectively enrolled in the study: 21 received filgrastim, 21 pegfilgrastim. Flow cytometry was used to determine the number of PBSC, myeloid, lymphoid, and megakaryocyte precursors in peripheral blood and apheresis product on day 1 of apheresis.

RESULTS: The median number of collected PBSC was 5.05 × 106 /kg in the filgrastim and 4.66 × 106 /kg in the pegfilgrastim group (p = 0.428). The median number of apheresis was 2.5 in the filgrastim and 2 in the pegfilgrastim group (p = 0.901). The number of megakaryocyte precursors in peripheral blood was significantly higher in the filgrastim group, but not in the apheresis products. There were no statistically significant differences in the myeloid and lymphoid precursors in the peripheral blood and in the apheresis products. The median time to neutrophil and platelet engraftment was 13 days and 16.5 days for filgrastim and 13 days and 16 days for pegfilgrastim group.

CONCLUSIONS: We can conclude that pegfilgrastim alone is at least equally successful as filgrastim alone for the PBSC mobilization in newly diagnosed myeloma patients.