Mobilization for Autologous Stem Cell Transplantation in Hodgkin's Lymphoma and Non-Hodgkin's Lymphoma: A Single Institution Experience

Background: Plerixafor (Mozobil) plus G-CSF is an FDA-approved strategy to mobilize hematopoietic stem cells (HSCs) in patients (pts) with NHL and Multiple Myeloma. We report our institutional experience mobilizing HSCs with and without plerixafor in pts with NHL and HL.

Methods: We collected data on all NHL (n=85) and HL (n=44) pts who underwent mobilization without chemotherapy between 2010 and 2012 at Ohio State University under IRB approved protocols.  Our standard is plerixafor on day 4 of G-CSF in pts who received radiation, ≥10 cycles of chemotherapy, are ≥age 60, or on day 5 to pts who had a CD34 count of <10/µL that morning.  Our target CD34+ cell yield is >5x10⁶ /kg recipient weight, with a minimum of >2x10⁶ /kg. Factors associated with sufficient mobilization were evaluated using univariate logistic regression models as well as graphical analyses.

Results: Most pts were male (56%) and Caucasian (91%), the median Karnofsky (KPS) score prior to transplant was 90 (range: 70-100); those who received plerixafor (n=88) tended to have lower KPS vs. G-CSF alone (n=41; p=0.07). Median age of the cohort was 54 years (range: 19-76), with HL pts younger than NHL pts (median: 37 vs. 60 years). Ability to collect >2x10⁶ /kg CD34+ cells on day 1 was highly associated with achieving a total yield of >5x10⁶ /kg CD34+ cells (OR=41.6; p<0.001). Both collection goals were significantly associated with earlier time to ANC engraftment (p<0.001). In the 88 pts who received plerixafor (75 NHL pts), the median number of doses was 2 (range: 1-3); 76% received their first dose on day 4 (range: 4-7). Patients who received day 4 plerixafor had significantly lower CD34 counts on day 4 than those that received G-CSF alone (p<0.001). Plerixafor use was highly associated with >2x10⁶  /kg on first collection (p=0.03), but not with the total number of collections or the ability to achieve a total yield of  >5x10⁶ /kg CD34+ cells. However, whether or not pts got plerixafor on day 4 vs. later was significantly associated with sufficient total CD34+ cell yield (37% vs. 10%; p=0.016).

Conclusions: Pts who received planned plerixafor on day 4 were more likely to achieve the target yield despite having risk factors for mobilization failure. Routine use of plerixafor in lymphoma pts who are less likely to be poor mobilizers may lead to fewer apheresis procedures, faster engraftment, and shorter hospital stays. The potential economic benefits of this strategy warrant further investigation.