Patients' outcome after rescue plerixafor administration for autologous stem cell mobilization: a single-center retrospective analysis

BACKGROUND: Plerixafor is predominantly used for patients mobilizing inadequate stem cell numbers for autologous transplantation after stimulation with granulocyte-colony-stimulating factor (G-CSF). STUDY DESIGN AND METHODS: We here report on 300 patients undergoing stem cell mobilization with G-CSF, among them 36 poor mobilizers (CD34+ cell counts < 50 x 10(6)/L blood) receiving G-CSF alone and 49 receiving G-CSF in combination with plerixafor for rescue intervention. Mobilization efficacy and short-time outcome after autologous stem cell transplantation were analyzed and compared in the respective subgroups. RESULTS: Out of 49 patients treated with plerixafor and G-CSF, 46 (94%) collected sufficient hematopoietic stem cell numbers although the number was clearly inferior in poor mobilizers. Compared to good mobilizers, viability of CD341 cells analyzed after collection was slightly reduced in poor mobilizers independent of the application of plerixafor. A total of 232 patients underwent autologous stem cell transplantation, among them 26 poor mobilizers who received only G-CSF and 31 patients who received G-CSF in combination with plerixafor. Time until neutrophil engraftment was in median 1 day later in poor mobilizers irrespective of the application of plerixafor. Platelet engraftment was in median 2 days delayed in patients mobilized with G-CSF and plerixafor compared to 1 day in poor mobilizers treated with G-CSF only. Frequency of detected CD381 CD1381 CD45-CD561 plasma cells in the apheresis products of myeloma patients was comparable for all groups. CONCLUSION: Our data demonstrate that plerixafor is highly effective as rescue measurement after mobilization failure with G-CSF alone and short-term clinical outcome after stem cell transplantation is comparable.