Salvage bone marrow harvest in patients failing plerixafor-based stem cell mobilization attempt: feasibility and autologous transplantation outcomes.

Inadequate mobilization of peripheral blood progenitor cells (PBPC) is sometimes a limiting factor to proceed with an autologous hematopoietic cell transplantation (auto-HCT), in an otherwise eligible patient. In such situations, a bone marrow harvest (BMH) procedure may be considered to achieve the CD34+ target dose for an autograft. Plerixafor-based mobilization has recently been shown to improve PBPC collection yields. However, the feasibility and outcomes of BMH in patients failing plerixafor-based mobilization is not known. We report here, 6 patients who underwent BMH after PBPC mobilization failure with plerixafor. The median CD34+ yield with plerixafor mobilization and BMH were 1.15 x 10^6/Kg (range, 0.2-1.7 × 10^6/Kg) and 0.32 (range, 0.12-0.38 × 10^6/Kg), respectively. Three patients proceeded to an auto-HCT, with only 1 patient receiving CD34+ cell dose of at least 2 × 10^6/Kg. While neutrophil recovery was seen, platelet recovery and red cell transfusion independence were delayed. All 3 autografted patients experienced disease progression by day +100. These data suggest, limited incremental benefit of a salvage BMH after plerixafor mobilization failure, cautioning against routine use of this strategy.