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

Plerixafor is predominantly used for patients mobilizing inadequate stem cell numbers for autologous transplantation after stimulation with granulocyte-colony-stimulating factor (G-CSF).

We here report on 300 patients undergoing stem cell mobilization with G-CSF, among them 36 poor mobilizers (CD34+ cell counts < 50 × 10⁶ /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.

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 CD34+ 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 CD38+ CD138+ CD45- CD56+ plasma cells in the apheresis products of myeloma patients was comparable for all groups.

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.