This prospective randomized trial is designed to determine if a lower dose of cyclophosphamide (1.5 gm/m2) will be as efficacious as the intermediate dose (3 gm/m2), based on cell number collected, number of apheresis required and resource utilization.~The time to collection of autologous hematopoietic stem cells was ten to twelve days following cyclophosphamide and daily filgrastim. Peripheral blood CD34+ cell numbers were examined beginning ten days after cyclophosphamide administration. Leukapheresis began once the blood CD34+ number reached 10 cells/mcl. Patients received consecutive days of leukapheresis, with the goal of collecting > 5 x 106 CD34+cells/kg. The collection process, concentration and storage of PBSC were similar for all patients. Briefly, a 4-blood volume leukapheresis PBSC collection was performed daily using a COBE Spectra cell separator (COBE BCT, Lakewood, CO). Collected cells were concentrated and cryopreserved. Cells were frozen in Cryocyte freezing bags (Nexell Therapeutics Inc.) in a controlled rate freezer (Custom BioGenic Systems, Shelby Township, MI). At the conclusion of this freezing, the cells were transferred to the vapor phase of a monitored liquid nitrogen freezer (CryoPlus III, Forma Scientific, Marietta, OH) at a temperature of -120 0C or below.
No prospective randomized trials have evaluated the most efficacious dose of cyclophosphamide to mobilize autologous stem cells. We previously demonstrated that the time to collection of autologous hematopoietic stem cells is 10-12 days following the one dose of cyclophosphamide and daily G-CSF (granulocyte-colony stimulating factor).9 This prospective randomized trial is designed to determine if a lower dose of cyclophosphamide (1.5 gm/m2) will be as efficacious as the intermediate dose (3 gm/m2), based on cell number collected, number of apheresis required and resource utilization.