Comparison of four different strategies of stem cell mobilization in patients with multiple myeloma.

Abstract

7039 Background: There is no consensus among institutions for the optimal strategy of peripheral blood stem cell (PBSC) collection for autologous stem cell transplantation (ASCT) in patients with multiple myeloma (MM). Methods: We retrospectively analysed the outcomes of PSBC collection in MM patients using the following mobilization regimens: cyclophosphamide 5,000 mg/m2 + etoposide 1,000 mg/m2 + G-CSF 5 mcg/Kg/day (Group A, n = 49); cyclophosphamide 2,000-3,000 mg/m2+ G-CSF 5 mcg/Kg/day (Group B, n = 25); G-CSF 16 mcg/Kg/day (Group C, n = 21); G-CSF 16 mcg/kg/day + plerixafor 0.24 mg/Kg (Group D, n = 128). Results: The median number of PBSC collected was 28.1 (range, 2.1-134), 4.5 (0.1-39.7), 4.0 (0-7.3) and 8.4 (0.2-41.2) million CD34+/kg in groups A, B, C and D, respectively (p <0.001). The mean number of collection days was 1.3, 2.2, 2.4, and 1.3 in groups A, B, C, and D, respectively (p <0.001). Febrile neutropenia occurred in 16 (32.7%), 1 (4%), 0, and 0 patients in groups A, B, C, and D, respectively. One patient who received CTX 3 g/m2 died of septic shock during the neutropenic phase. Failure to collect PBSC, defined as <2x106 CD34+ cells/Kg for a planned single ASCT or <4x106 for planned tandem ASCTs, was observed in 2/49 (4%), 5/25 (20%), 4/21 (19%), and 9/128 (7%) patients in groups A, B, C, and D respectively (p=0.037). Conclusions: Plerixafor + G-CSF provided the greatest benefit to risk ratio for PSBC collection in MM patients.