A combination of dexamethasone, cyclophosphamide, etoposide, and cisplatin is less toxic and more effective than high-dose cyclophosphamide for peripheral stem cell mobilization in multiple myeloma.

Background and Objectives. The purpose of this study was to compare the efficacy and toxicity of two regimens for peripheral blood stem cell (PBSC) mobilization in multiple myeloma (MM) patients. Design and Methods. From 1995 to 2001, 116 patients were enrolled in two high-dose programs including autologous transplantation, adopting two mobilizing regimens: 61 patients were mobilized with high-dose cyclophosphamide (HD-Cy) at 4 g/m(2) (group 1), and 55 patients with DCEP (dexamethasone, cyclophosphamide, etoposide, and cisplatin) (group 11), both followed by granulocyte colony-stimulating factor (G-CSF 5 mug/Kg/day) started 48 hours after chemotherapy. Results. The median number of CD34(+) cells harvested was similar in the two groups (5.9 vs 5,82x10(5) cells/kg). The target of at least 4x10(6) cells/kg was reached in a higher percentage of patients in the DCEP group (75 vs 59%) (p=0.05). The proportion of poor mobilizers (<2x10(6) CD34(+) cells/kg) was 21% with HD-Cy and 13% with DCEP (P=NS). In group 1, 10 patients (16%) required packed red cell transfusions, 5 patients (8%) platelet support, and the majority of patients (87%) had a neutrophil count below 500/muL, whereas none did so in group 11 (p=0.0009, p=0.01, p=0.0009, respectively). Neutropenia-related fever occurred in 18% of patients in group I versus 0% in group 11 (p=0.0005). WHO grade >II extra-hematologic toxicities (microhematuria, cystitis, infections) were seen in 8 patients (13%) of group I vs 0 in group 11 (p=0.007). Interpretation and Conclusions. DCEP is a better tolerated and more effective regimen than HD-Cy for peripheral stem cell mobilization in MM patients assigned to high-dose therapy programs.