GCSF Alone or in Combination with Cyclophosphamide (C) or GM-CSF for Hematopoietic Stem Cell Mobilization (HSCM) for Autologous Peripheral Blood Stem Cell Transplant (AHPCT): A Retrospective Review of a Single Center Experience

The mechanisms of HSCM are not completely understood and involve the action of multiple cytokines and adhesion molecules. Historically, HSCM for AHSCT has been done using high dose chemotherapy, usually C, with growth factor (G-CSF or GM-CSF). However, the need for the chemotherapy in this instance has not been defined. We, retrospectively compared three HSCM approaches; C and GSCF, G-CSF and GM-CSF, and G-CSF alone in our institution from 2005–2007. Results: C (2.5gm/m2) with G-CSF (10mcg/kg) was used in 25 patients (pts) (n=18 multiple myeloma [MM], n=5 non-Hodgkin’s lymphoma [NHL], n=1 Hodgkin’s disease [HD] and n=1 systemic sclerosis). G-CSF 5mcg/kg with GM-CSF 5mcg/kg was used for HSCM in 10 pts (n=8 NHL and n=2 MM). G-CSF alone (10mcg/kg for at least 4 days) was used in 49 pts (n=28 MM, n=13 NHL, n=2 HD and n=6 other diagnosis). The age range was 35–72 in the C and G-CSF group, 30–69 in the G-CSF and GM-CSF, and 25–72 in the GCSF alone group. The median CD34+cells/kg collected was 6.4×10⁶ (range 0.97–131), 12×10⁶ (range 0.23–6.7), and 4.59×10⁶ (range 0.66–7.38) in the C and GCSF, G-CSF and GM-CSF, and the G-CSF groups respectively. The collection sessions ranged from a median of 2.0 days (1 day in 44% pts, 2 days in 28%, 3 days in 16% and 4 days in 12% of pts) in the C and G-CSF group; to 2.5 days (1 day in 20% of pts, 2 days in 30%, 3 days in 30% and 4 days in 20% of pts) in the G-CSF and GM-CSF group; and 2 days (1 day in 22% of pts, 2 days in 37%, 3 days in 30% and 4 days in 10% of pts) in the G-CSF alone group. 3 pts (12%) failed HSCM with C plus GCSF, 1 subsequently collected with G-CSF alone. 5 pts (50%) failed HSCM with G-CSF +GMCSF, 2 of these had previously failed G-CSF alone, and 2 were re-mobilized with AMD 3100 protocol and 1 with C and GCSF. 6 pts (12%) failed HSCM with G-CSF alone, 3 subsequently underwent HSCM with higher dose of G-CSF and 2 were enrolled on AMD-3100 study. 2 pts (8%) with C and G-CSF HSCM developed neutropenic fever and needed hospitalization. All pts who had adequate HSCM (at least 2×10e6/kg) and subsequently underwent AHPCT had white blood and platelet engraftment. There was no difference in the day to engraftment based on the HSCM strategy. These data show that HSCM with G-CSF alone results in similar stem cell yield and stem cell collection sessions to C and G-CSF. Although the latter strategy achieved a higher median number of HSC (4.9 vs. 6.4 xe6/kg), this was not statistically significant (p= 0.08) in this group of pts. A higher percentage of pts achieved target stem cell collection in one day with C plus G-CSF (44%), than G-CSF alone (22%). On the other hand, the combination of C plus G-CSF carries risks related to high dose chemotherapy and necessitates hospitalization for its administration and management of neutropenic fever. The G-CSF+GM-CSF combination was the least effective in adequate HSCM. Analysis of DFS in the three mobilization strategies is pending.