Efficacy and safety of stem cell mobilization with cyclophosphamide plus etoposide versus cyclophosphamide alone

The use of the combination of two cytostatics cyclophosphamide (CTX) and etoposide (VEP) and G-CSF is a reasonable alternative, especially for stem mobilization in multiple myeloma (MM) patients from countries in which newer treatments are limited due to financial constraints. The aim of this study was to compare the efficacy and safety of CTX-VEP versus CTX alone for mobilization of hematopoietic stem cells in MM patients. The analysis included 48 consecutive MM patients mobilized with CTX-VEP compared to 43 consecutive historical controls mobilized with CTX alone. The two groups of MM patients did not differ in terms of the median number of apheresis procedures, median yield the first day, median numbers of harvested CD34+ cells, proportion of patients with at least 5 x 10⁶/kg yield and incidence of non-hematological complications. The median cumulative dose of G-CSF given to individuals in the CTX-VEP group was significantly lower than in the CTX group (p < 0.001). The incidence of post-mobilization thrombocytopenia was higher in the CTX group (p<0.001). The median time to platelet count > 20 x 10⁹/l (10 vs. 11 days, p = 0.004) and the median time to neutrophil count > 50 x 10⁹/l (11 vs. 13 days, p < 0.001) were significantly shorter among the patients mobilized with CTX-VEP than in those treated with CTX alone. These findings suggest that CTX-VEP is as efficacious and possibly safer than CTX alone.