Efficacy of late afternoon plerixafor administration for stem cell mobilization Cynthia El Rahi, PharmD; James Cox, PharmD; Rammurti Kamble, MD PURPOSE
Inadequate hematopoeitic progenitor cell (HPC) mobilization is seen in approximately 25% of patients undergoing stem cell collection prior to autologous hematopoeitic stem cell transplantation (HSCT). Plerixafor is indicated in combination with granulocyte-colony stimulating factor (G-CSF) for HPC mobilization prior to autologous HSCT for non-Hodgkin’s lymphoma (NHL) and multiple myeloma (MM). It reversibly inhibits the binding of stromal cell-derived factor-1, expressed on bone marrow stromal cells, to the CXC chemokine receptor 4 resulting in mobilization of HPCs from bone marrow into peripheral blood. Pharmacodynamics studies in healthy volunteers demonstrated a sustained elevation in the peripheral blood (PB) CD34+ count from 4 to 18 hours with a peak between 10 and 14 hours. In response to this, the manufacturer recommends administration of plerixafor approximately 11 hours prior to initiation of apheresis, which translates into an administration time of 10–11 p.m. In June 2013, the FDA added language to the safety labeling warning of the risk of anaphylactic reactions occurring during and immediately after administration, and recommended that patients be monitored for at least 30 minutes after administration. Following this guidance and based on pharmacodynamic data suggesting sustained effects of plerixafor at 18 hours, our clinic changed practice in July 2013 to administer plerixafor at 4 pm. To date, there are few descriptions showing the efficacy of earlier administration of plerixafor in achieving desired HSC collection efficiencies.
This aim of this study was to retrospectively compare the stem cell collection efficiency of patients treated with plerixafor before and after the change in practice at our institution. METHODS
A retrospective chart review of patients with NHL and MM, who received a plerixafor-containing mobilization regimen prior to autologous HSCT, was conducted. RESULTS
208 patients were included in the analysis (68 and 140 patients in the 4 p.m. and 10 p.m. administration time groups, respectively). 91% of patients in the 4 p.m. group achieved minimal CD-34+ cell goal (2 × 106 CD34+ cells/kg) in ≤2 apheresis days compared to 89% in the 10 p.m. group (p=0.804) resulting in comparable stem cell collection efficiency. CONCLUSION
Late afternoon administration of plerixafor is as effective as 10 p.m. plerixafor administration. This finding validates our current practice for late afternoon administration of plerixafor.
PGY2 ONCOLOGY RESIDENCY
Cynthia El Rahi, PharmD Cynthia earned her Doctor of Pharmacy from the Lebanese American University College of Pharmacy in 2012. Most recently, she worked as a clinical pharmacist at Houston Methodist Hospital after completion of her PGY1 Pharmacy Residency at Houston Methodist Hospital before beginning her PGY2 training. Cynthia has accepted an oncology clinical specialist position at Houston Methodist Hospital. Primary project preceptor: James Cox, PharmD Presented at 2016 Hematology Oncology Pharmacy Association Annual Conference, Atlanta, Ga.
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