Mobilization strategies with and without plerixafor for autologous stem cell transplant in patients with multiple myeloma.

Autologous stem cell transplantation is a standard treatment strategy for patients with multiple myeloma that requires effective mobilization and apheresis of peripheral blood progenitor cells; however, in the current era of novel myeloma induction therapies, the optimal mobilization regimen to enhance stem cell yield while limiting toxicity and resource utilization remains unknown. In this multicenter retrospective study, we assessed apheresis and transplant outcomes in myeloma patients mobilized with granulocyte colony stimulating factor (G-CSF) alone (n = 62), G-CSF with chemotherapy (n = 43), or G-CSF with the CXCR4 antagonist plerixafor (n = 417). Compared to patients treated with G-CSF alone, the plerixafor group required significantly fewer median apheresis sessions (1 vs 2, p = 0.0023) with higher CD34+ stem cell yield (9.9 vs 5.8 × 106 cells/kg, p < 0.001) and had significantly faster engraftment of neutrophils (HR 1.54, 95% CI 1.17-2.03) and platelets (HR 2.24, 95% CI 1.69-2.96) after transplant. Additionally, the plerixafor group showed a significantly better toxicity profile and lower adverse event rate than patients treated with G-CSF alone (p = 0.0028) or chemomobilization (p < 0.0001), with a trend toward reduced survival in chemomobilization patients. Taken together, these data support the routine use of plerixafor-based mobilization to increase apheresis efficiency and reduce toxicity in myeloma patients undergoing transplant.