Plerixafor is effective given either preemptively or as a rescue strategy in poor stem cell mobilizing patients with multiple myeloma

Abstract

BACKGROUND:Harvest of more than one CD34+ stem cell transplant has become the standard, to ensure the option for a second autologous transplantation in patients with relapsed or progressive multiple myeloma (MM). Additional administration of the CXCR-4 inhibitor plerixafor has been shown to increase the efficiency of CD34+ stem cell harvest. However, the algorithm when to apply plerixafor is still under debate. STUDY DESIGN AND METHODS:In this retrospective study, 46 MM patients were categorized into four groups according to their CD34+ stem cell count in peripheral blood (PB) and mobilization with or without plerixafor: Group A comprised poor mobilizers with CD34+ cell counts of fewer than 20 × 10 6 /L in PB. Group B included inadequate mobilizers with CD34+ cell counts of 20 × 10 6 /L or more in PB and a low CD34+ stem cell yield in the first leukapheresis session. Patients receiving plerixafor preemptively (Group A1) and as a rescue strategy (Group B1) were compared to patients continuing stem cell collection with granulocyte-colony-stimulating factor alone (Groups A2 and B2). RESULTS: In both, the preemptive and the rescue settings, plerixafor enhanced the CD34+ stem cell yield significantly. Poor mobilization and administration of plerixafor was not associated with delayed engraftment. CONCLUSION: Our data demonstrate that administration of plerixafor is safe and effective and facilitates a significantly higher CD34+ stem cell harvest. Based on the presented data, we propose an algorithm for the use of plerixafor for CD34+ stem cell mobilization and harvesting in poor mobilizing myeloma patients.

Plerixafor for Autologous Stem-Cell Mobilization and Transplantation for Patients in Ontario

“…This recommendation is supported by seven nonrandomized studies that reported a variety of outcomes, including number of stem cells collected and number of days of apheresis 10,11,13,15,16,24,27 . In general, those studies detected that a better mobilization response is achieved in patients failing their first mobilization attempt when plerixafor is added to their existing mobilization regimens.…”

“…The study by Hundemer et al 10 , in which data were matched with a historical control group on the basis of poor stemcell yield in the first apheresis session, reported a median CD34+ collection of 4.9 in 2 apheresis procedures with plerixafor and 3.7 in 4 apheresis procedures with g-csf (p = 0.01). The comparative study reported by Cheng et al 13 reported a median CD34+ collection of 8.5 for patients receiving plerixafor compared with 4.8 for patients not receiving plerixafor (p = 0.003), but the median number of apheresis procedures was not reported. Three single-arm studies 16,24,27 reported median numbers of CD34+ cells of 2.9, 5.08, and 3.42 with a median number of apheresis procedures of 1 (range: 1-3), 5 (range: 1-10), and 2 (range: 1-4) respectively.…”

“…Cheng et al 13 reported that all patients (100%) in the group receiving plerixafor and 83% of patients in the group not receiving plerixafor underwent transplantation, but statistical significance was not reported. The single-arm study by Smith et al 27 reported that, among patients who seem to mobilize poorly and who received just-in-time rescue plerixafor plus chemotherapy and g-csf, 95% proceeded to asct.…”

“…In general, those studies detected that a better mobilization response is achieved in patients failing their first mobilization attempt when plerixafor is added to their existing mobilization regimens. Additionally, three studies demonstrated that a significant proportion of patients were able to proceed to asct with plerixafor 13,15,27 .…”

“…Twenty-two studies assessing the efficacy and safety of plerixafor for autologous stem-cell mobilization and transplantation were retained: two randomized controlled trials (rcts) 6,7 , five nonrandomized controlled trials [8][9][10][11][12] , three retrospective cohort studies with a contemporaneous control arm [13][14][15] , and twelve single-arm studies [16][17][18][19][20][21][22][23][24][25][26][27] .…”