No randomized trials comparing chemomobilization vs. plerixafor plus G-CSF in patients with myeloma have been published. While a few retrospective studies have reported on the relative efficacy of cyclophosphamide-based mobilization against plerixafor and G-CSF, they included patients receiving either LD-CY or doses above 4mg/m2, contained patients with non-Hodgkin lymphoma (NHL), and likely included MM patients receiving conventional induction regimens. Awan et al. retrospectively compared that efficacy, toxicity and cost of PBPC mobilization with G-CSF and either ID-CY or plerixafor, in MM patients receiving only novel induction regimens. Compared to plerixafor, ID-CY use was associated with higher median peak peripheral blood CD34+ cell count (68/µL vs. 160/µL, p<0.001), and CD34+ cell yield on day 1 of collection (6.9 x 106/kg vs. 11.7 x 106/kg, p=<0.001). No patients in either group had mobilization failure. The total CD34+ cell yield was significantly higher in the ID-CY patients (median collection 16.6 x 106 cells/kg vs. 11.6 x 106 cells/kg; p-value <0.001). Mobilization with ID-CY was associated with significantly more frequent episodes of febrile neutropenia (16.3% vs. 0%; p=0.02), higher use of intravenous antibiotics (16.3% vs. 3%; p=0.03), transfusion support and need for hospitalizations (p=0.02). The average total cost of mobilization in the plerixafor group was significantly higher compared to the ID-CY group ($28,980 vs. $22,504.8; p-value=0.001). This study showed lower mobilization costs but greater toxicity with chemotherapy based mobilization in MM. The limitations of the analysis include small sample size and retrospective nature. Of note LD-CY in a different study was shown to be inferior to plerixafor in terms of PBPC mobilization efficacy and collection failure rates.