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Background Plerixafor is a recently introduced agent used to improve peripheral blood stem cell ( PBSC) mobilization in patients with hematologic malignancies. However, some patients still cannot mobilize adequately even with plerixafor. Study Design and Methods We retrospectively reviewed the PBSC collections of 18 consecutive lymphoma and multiple myeloma patients, who had previously mobilized poorly despite the use of plerixafor and received plerixafor again during remobilization. Results During the first mobilization attempt, all 18 recombinant granulocyte-colony-stimulating factor ( G- CSF; two) or G- CSF plus chemotherapy-mobilized patients (16) had poor response to plerixafor, with peripheral blood ( PB) CD34+ counts ranging from 0 to 7.48 × 106/ L after the first dose. They collected only 0.15 × 106 to 1.63 × 106 (median, 0.40 × 106) CD34+ cells/kg after one to four collections. The median average daily yield was 0.24 × 106 CD34+ cells/kg. Remobilization began 1 to 4 weeks later with G- CSF, plerixafor, and with (three) or without (15) cyclophosphamide. The PB CD34+ cell counts after the first dose of plerixafor were 3.04 × 106 to 127.54 × 106/ L (median, 14.58 × 106/ L). After one to four doses of plerixafor, each patient collected an additional 0.39 × 106 to 14.02 × 106 (median, 1.89 × 106) CD34+ cells/kg, and the median daily average was 0.78 × 106 CD34+ cells/kg. Cumulatively, after two rounds of collections, 15 collected more than 2.0 × 106 CD34+ cells/kg. Thirteen have proceeded to autologous stem cell transplantation ( ASCT) and successfully engrafted. Conclusion In patients who had responded poorly to the use of plerixafor as a mobilization salvage agent, response to remobilization with plerixafor for the second time was variable, but most (83.3%) patients were able to collect enough PBSCs to proceed to ASCT. [ABSTRACT FROM AUTHOR]

BACKGROUND: The successful mobilization and collection of hematopoietic stem cells are dependent on a number of clinical factors such as previous chemotherapy and disease stage. The aim of this retrospective study was to determine whether the effectiveness of mobilization and collection is an independent prognostic factor for autologous stem cell transplantation outcome. STUDY DESIGN AND METHODS: A total of 358 patients who received transplants from January 2003 to December 2004 (201 male and 157 female patients, ages from 2.7 to 77.3 years with median of 53 years of age) underwent autologous hematopoietic stem cell collection after mobilization with granulocyte–colony-stimulating factor (G-CSF) or G-CSF plus chemotherapy priming. This retrospective study included patients with diagnoses of acute myelogenous leukemia, non-Hodgkin's lymphoma, Hodgkin's disease, multiple myeloma, and solid tumors. All patients underwent stem cell collection until a target or a minimum CD34+ cell dose was reached. Correlations were performed between stem cell mobilization and/or collection efficacy and transplantation outcomes. RESULTS: In general, both larger reinfused CD34+ cell dose and shorter number of days for the stem cell count to reach the minimum of 2 × 106 per kg CD34+ cells do not foster quicker engraftment. Reinfused CD34+ cell dose of less than 12 × 106 and number of days stem cell collection to reach this minimum CD34+ cell dose did not independently affect the overall survival (OS) or disease-free survival (DFS). CONCLUSION: The effectiveness of hematopoietic stem cell mobilization and collection as defined as number of days to reach a CD34+ cell dose of 2 × 106 per kg should not be used independently to forecast posttransplantation prognosis, engraftment, DFS, and OS. [ABSTRACT FROM AUTHOR]