Peripheral blood stem cell mobilization in multiple myeloma patients treat in the novel therapy-era with plerixafor and G-CSF has superior efficacy but significantly higher costs compared to mobilization with low-dose cyclophosphamide and G-CSF

Studies comparing the efficacy and cost of peripheral blood stem and progenitor cells mobilization with low‐dose cyclophosphamide (LD‐CY) and granulocyte‐colony stimulating factor (G‐CSF) against plerixafor and G‐CSF, in multiple myeloma (MM) patients treated in the novel therapy‐era are not available. Herein, we report mobilization outcomes of 107 patients who underwent transplantation within 1‐year of starting induction chemotherapy with novel agents. Patients undergoing mobilization with LD‐CY (1.5 gm/m2) and G‐CSF (n = 74) were compared against patients receiving plerixafor and G‐CSF (n = 33). Compared to plerixafor, LD‐CY was associated with a significantly lower median peak peripheral blood CD34+ cell count (68/µL vs. 36/µL, P = 0.048), and lower CD34+ cell yield on day 1 of collection (6.9 × 106/kg vs. 2.4 × 106/kg, P = 0.001). Six patients (8.1%) in the LD‐CY group experienced mobilization failure, compared to none in the plerixafor group. The total CD34+ cell yield was significantly higher in the plerixafor group (median 11.6 × 106/kg vs. 7 × 106/kg; P‐value = 0.001). Mobilization with LD‐CY was associated with increased (albeit statistically non‐significant) episodes of febrile neutropenia (5.4% vs. 0%; P = 0.24), higher use of intravenous antibiotics (6.7% vs. 3%; P = 0.45), and need for hospitalizations (9.4% vs. 3%; P = 0.24). The average total cost of mobilization in the plerixafor group was significantly higher compared to the LD‐CY group ($28,980 vs. $19,626.5 P‐value