246 Comparison of two stem cell mobilization and harvesting regimens for peripheral blood stem cell (PBSC) transplantation in multiple myeloma (MM)

We have investigated two regimens for the mobilisation of stem cells prior to PBSC transplantation in MM. Regiman A: 125 μg/m 2 GCSF b.d. for 7 days with harvest of stem cells days 5–8. Regimen B: 12–16 μg/kg for 4 days with harvest days 4 and 5. For each regimen the median total cell count, CFU-GM and CD34 + counts and days to engraftment as measured by time to attainment of neutrophil count 500 were calculated and compared by the Mann-Whitney non-parametric test. Results A(n = 25) B(n = 13) Mann-Whitney p value Total cell count (× 10 8 ) 6.6 (4.05–12.18) 4.06(30–7.72) 0.0002 CFU-GM (× 10 4 /kg) 3.14 (0.44–24.5) 3.35 (0.06–21.27) NS CD34+ (× 10 6 ) 43.6(0.3–337.7) 38.5(4.1–1187.7) NS Days to engraftmem 12(6–21) 12(8–23) NS Condusions Although Regimen A led to increased mononuclear cell count there was no difference in the CFU-GM or CD34+ counts or days to engraftment. Reduction of stem cell harvest time from 4 to 2 days has economic benefits and improves patient tolerability.