Plerixafor for patients who fail cytokine-or chemotherapy-based stem cell mobilization: Results of a prospective study by the Polish Lymphoma Research Group (PLRG)

Autologous hematopoietic stem cell transplantation (autoHSCT) requires collection of sufficient number of hematopoietic stem cells. The goal of this study was to evaluate efficacy of plerixafor used in patients with lymphoid malignancies failing conventional stem cell mobilization. This was a prospective, non-interventional study. All consecutive patients (n = 109) treated with plerixafor in 11 centers were reported. The drug was used either in case of previous mobilization failure (n = 67) or interventionally, in case of insufficient CD34 cell output during current mobilization (n = 42). Successful mobilization was defined as resulting in collection of ≥ 2 × 10 CD34 cells/kg for single autoHSCT or ≥ 4 × 10 CD34 cells/kg for double procedure. The overall rate of successful mobilization was 55% (55% for single and 56% for double autoHSCT). The median total number of collected CD34 cells/kg was 2.4 (range, 0-11.5) for patients intended for a single transplantation while 4.0 (0.6-16.9) for double procedure. The number of circulating CD34 cells increased after the use of plerixafor regardless of baseline values. The median fold increase was 3.3 (0.3-155). Data from this observational study confirm high efficacy of plerixafor used in routine clinical practice as salvage for patients with lymphoid malignancies failing conventional stem cell mobilization.