Increased Efficacy of Stem Cell Chemomobilization with Intermediate-Dose Cytarabine Plus Granulocyte Colony-Stimulating Factor (G-CSF) Compared with G-CSF Alone in Patients with Multiple Myeloma: Results of a Randomized Trial

Mobilization of hematopoietic stem cells for patients with multiple myeloma (MM) may be done using either steady-state granulocyte colony-stimulating factor (G-CSF) or a combination of chemotherapy with G-CSF. The goal of this randomized, open-label, phase 3 trial was to compare the efficacy of chemomobilization using intermediate -dose cytarabine (ID-AraC) plus G-CSF with G-CSF alone in patients with MM referred for tandem autologous stem cell transplantation (autoSCT). The percentage of patients with stem cell yield of at least 5 x 10(6) CD34(+) cells/kg was the primary endpoint. Ninety patients were enrolled, including 44 assigned to the ID-AraC arm and 46 in the G-CSF arm. The threshold number of CD34(+) cells was reached in 43 patients (98%) in the ID-AraC arm and in 32 patients (70%) in the G-CSF arm (P =.0003). The median number of collected CD34(+) cells was 20.2 x 10(6) cells/kg in the ID-AraC arm versus 5.9 x 10(6) cells/kg in the G-CSF arm (P <.000001). A single apheresis was sufficient to achieve the required number of harvested CD34(+) cells in 37 patients (86%) in the ID-AraC arm and in 13 patients (41%) in the G-CSF arm (P=.00008). The times to both neutrophil and platelet recovery after autoSCT were significantly shorter in the patients mobilized with ID-AraC. This study provides the first evidence of the advantage of chemomobilization over G-CSF monotherapy in terms of efficacy. ID-AraC with G-CSF should be the preferred chemomobilization protocol for patients with MM scheduled to undergo tandem autoSCT. (C) 2018 American Society for Blood and Marrow Transplantation.