Successful mobilization, intra-apheresis recruitment, and harvest of hematopoietic progenitor cells by addition of plerixafor and subsequent large-volume leukapheresis.

Background: In patients failing successful conventional mobilization of hematopoietic progenitor cells (HPC) plerixafor (Mozobil (R)) seems to be an alternative. We report a series of 14 patients with multiple myeloma or NHL successfully mobilized and harvested by plerixafor together with large-volume leukaphereses (LVL). Methods: In a first series (GI), 5 patients were mobilized with G-CSF and plerixafor. In the second series (GII), 9 patients were mobilized by chemotherapy, G-CSF, and plerixafor. Results: In GI and GII, addition of plerixafor led to a significant (p < 0.01) increase of leukocytes and CD34+ cells in peripheral blood (PB). In GII, the median number of CD34+ cells in PB before and after addition of plerixafor was significantly (p = 0.019) higher compared to GI (9 vs. 5 and 50 vs. 24 cells/mu l, respectively). In GI and GII, a median number of three or one aphereses was performed. In GII, the median yield (6.7 x 10(6) CD34+ cells/kg) of the first apheresis and the median intra-apheresis recruitment of CD34+ cells were significantly (p < 0.05) higher compared to GI (2.94 x 10(6) CD34+ cells/kg). All patients transplanted, 5 in GI and 8 in GII, exhibited successful engraftment. Conclusions: Plerixafor and G-CSF mobilization or the addition of plerixafor during non-optimal chemotherapy and G-CSF mobilization together with LVL enabled, independent of leukocyte count and even without detectable CD34+ cells before addition of plerixafor, sufficient harvest of HPC numbers for transplantation. Addition of plerixafor during chemotherapy and G-CSF mobilization led to an increased intra-apheresis recruitment and a significantly higher yield of CD34+ cells compared to plerixafor and G-CSF steady-state mobilized patients.