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/m2 (group I), and 55 patients with DCEP (dexamethasone, cyclophosphamide, etoposide, and cisplatin) (group II), both followed by granulocyte colony-stimulating factor (G-CSF 5 mg/Kg/day) started 48 hours after chemotherapy.
Results: The median number of CD34+ cells harvested was similar in the two groups (5.9 vs 5.82x106 cells/kg). The target of at least 4x106 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 (<2x106 CD34+ cells/kg) was 21% with HD-Cy and 13% with DCEP (P=NS). In group I, 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/mL, whereas none did so in group II (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 II (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 II (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.