(P-BT-8) Considerations for Optimization of Apheresis Hematopoietic Progenitor Cell Collection from Haploidentical Matched Related Donors: A Single-Center Retrospective Review of 23 Donor Collections

Haploidentical donors present a particular challenge in the apheresis collection of hematopoietic progenitor cells (HPC) for allogeneic hematopoietic stem cell transplant (HSCT).  Based on the literature, our institutional collection goal is >5 x 10^6 CD34+ cells/kg.  If this goal is not achieved in the first day of collection, an overnight hospital stay is required for central line care precautions.  Furthermore, multi-day collections pose problems with the timing of post-transplant cyclophosphamide. Off-label use of “up-front” plerixafor in this donor population prior to apheresis may allow for more one-day collections, leading to simplified timing of post-transplant cyclophosphamide, lower overall cost, and increased donor satisfaction.  We retrospectively analyzed our collection data of 23 haploidentical donors to identify risk factors for suboptimal collection and to propose appropriate risk-based practice modifications to maximize the rate of one-day collections.


Study

Design/Methods: We identified 23 haploidentical donors who underwent apheresis collections between September 2022 and present. We reviewed demographic data, line access, mobilization strategies, and collection yields.

Results/Findings: All 23 donors were mobilized with at least 5 days of G-CSF.  One donor received up-front plerixafor due to a low CD34 count the day before collection and collected in one day. Four donors received plerixafor prior to the second day of collection; possible factors for requiring a second day of collection included recipient weight >20kg more than donor weight, reduced flow rates related to peripheral access, and older age.  Of note, some donors collected in one day in spite of risk factors, including older age and lower weight.

Conclusions: Our experience suggests the following approaches to optimize collection of haploidentical donors: 1) Check a peripheral pre-CD34 count the day prior to collection and give up-front plerixafor based on a prespecified threshold such as CD34 < 40/µL; 2) Consider up-front plerixafor for donors >40-50 years of age and for donors >20kg smaller than the recipient; and 3) Consider central venous catheters over peripheral access, to achieve higher flow rates in donors at risk for suboptimal collection.