Impact of Plerixafor Use at Different Peripheral Blood CD34+ Thresholds on Autologous Stem Cell Collection in Patients with Multiple Myeloma

Abstract

Patients with multiple myeloma (MM) scheduled for autologous stem cell transplantation must undergo autologous stem cell mobilization; unfortunately, however, many do not obtain an adequate collection yield. Despite the availability of plerixafor, its widespread and uniform use is limited by its cost, and consequently, many institutions have adopted various risk-adapted algorithms. We report our mobilization experience as we have modified our plerixafor algorithm to a more liberal one, with the expectation of greater collection efficiency and mobilization success with higher plerixafor use. A total of 344 mobilization attempts were analyzed over 3 time periods and using 3 different peripheral blood CD34 + cell counts to guide plerixafor use: <15/mL (n = 66), <20/mL (n = 130), and <40/mL (n = 148). The primary endpoints were evaluation of changes in mean plerixafor utilization and apheresis days and assessment of the impact on overall mobilization costs. Secondary endpoints were a description of the impact of lenalidomide use on mobilization and evaluation of the rate of mobilization failure. We found that mean plerixafor use increased from 1.32 to 1.65 to 1.74 doses per mobilization (P = .026) and the mean days of apheresis decreased from 2.15 to 2.17 to 1.89 days per mobilization for the <15/mL, <20/mL, and <40/mL cohorts, respectively (P = .011). The combined cost of plerixafor and apheresis procedures at a threshold of 40/mL is close to that at a threshold of 15/mL, while saving 26 apheresis days per 100 patients. In general, there were low rates of mobilization failure across all thresholds. Patients who received more than 6 cycles of lenalidomide demonstrated impaired mobilization and required more apheresis sessions (P < .013) and greater plerixafor use (P < .001) to achieve target stem cell yields. Overall, using plerixafor in patients with MM, with a day 4 pCD34 count of <40/mL is a reasonable and cost-effective strategy to optimize apheresis utilization.

Prolonged Lenalidomide Induction Does Not Significantly Impair Stem Cell Collection in Multiple Myeloma Patients Mobilized With Cyclophosphamide or Plerixafor: A Report From The Covid Era

“… 14 Mobilization with cyclophosphamide and/or plerixafor is routinely employed at our center, and we have had very few patients in whom collection of sufficient cells for transplant has failed. This is consistent with studies suggesting that use of cyclophosphamide 15 , 16 , 17 , 18 , 19 and/or plerixafor 20 , 21 , 22 , 23 enables the majority of lenalidomide treated patients to collect adequate cells for transplant, even among those treated with more than 6 cycles of lenalidomide. 24 However, few studies have explored the impact of prolonged induction in substantial number of patients, and no studies have described the impact of prolonged induction in patients mobilized exclusively with the assistance of cyclophosphamide or plerixafor.…”

Stem cell yield and transplantation in transplant-eligible newly diagnosed multiple myeloma patients receiving daratumumab + bortezomib/thalidomide/dexamethasone in the phase 3 CASSIOPEIA study

“… 13 , 14 Close monitoring and early implementation of plerixafor could be considered for patients with risk factors for lower yield. 15 Differences between treatment arms reached statistical significance for several parameters of stem cell mobilization, harvesting, and transplant. However, these differences were ultimately not clinically relevant, as posttransplant hematopoietic reconstitution was nearly identical (99.8% vs. 99.6%) in both treatment arms.…”

“…13,14 Close monitoring and early implementation of plerixafor could be considered for patients with risk factors for lower yield. 15 The study flow diagram is shown for the CASSIOPEIA study from first randomization through completion of autologous stem cell transplant. The daratumumab group received daratumumab/bortezomib/thalidomide/dexamethasone; the control group received bortezomib/thalidomide/dexamethasone.…”

Incorporating hematopoietic stem-cell transplantation after second-line carfilzomib-lenalidomide-dexamethasone (KRd)

“…Although there are no guidelines on this, consensus is that collection should be done between the second and fourth cycles of lenalidomide, and that stem-cell reserve is significantly altered beyond six cycles. [19][20][21] For Group 2 patients, the median cycle of KRd was five (range 3-10), and cell collection was carried out within 3-5 cycles of KRd in all cases. There was one unfortunate case in Group 1, who progressed after three cycles of VTD (best response to VTD being stable disease) and was subsequently put on KRd with the intention to go into transplant.…”