Comparison of High-Dose Cyclophosphamide Plus G-CSF with G-CSF Alone for Peripheral Blood Stem Cell Mobilization in MM

ABSTRACT Background We report the results of two different methods of stem cell collection for autologous transplantation in 34 patients with MM. Methods In group I (n = 15), Highdose-CY, 4 g/m2 i.v., was administered followed by G-CSF, 10 µg/kg/day s.c., until the end of collection, starting the leukaphereses after hematological recovery (WBC >5000 × 106/l). In group II (n = 19), G-CSF, 10 µg/kg/day s.c., was used alone until the last day of collection, starting consecutive aphereses on the 5th day. Results Both patient groups were comparable for age, sex and clinical prognostic features as well as previous therapies. Median total yields of CD34+ cells had not significant differences between two groups (9.0 × 106 cell/kg versus 6.44 × 106 cell/kg, P = 0.26). Successful collection more than 5.0 × 106 CD34+ cells/kg and not failed collection of at least 2.0 × 106 CD34+ cells/kg were achieved in similar proportions in two groups (60.0% versus 57.9%, P > 0.999 and 73.3% versus 89.5%, P = 0.37). The significant differences of yields on day 1 ≥ 2.0 × 106 CD34+ cells/kg were not observed either (66.7% versus 57.9%, P = 0.601). Hospitalization for PBPC mobilization was longer in group I (18 days versus 9 days, P 0.5 × 109/l) and platelet engraftment (>50 × 109/l) were observed between both groups (10 days versus 11 days and 14 days versus 16 days, respectively). Conclusions These data suggest that adequate CD34+ cell collections can be achieved with both regimens of HD-CY plus G-CSF and G-CSF alone in most MM patients and G-CSF alone as mobilization regimen is cost-effective with less toxicity and with simplification of the procedure.