Efficacy of Afternoon Plerixafor Administration for Stem Cell Mobilization.

Background: When used for hematopoietic stem cell mobilization, plerixafor was originally recommended to be administered 11 hours prior to apheresis based on the peak effect of 10 to 14 hours translating into an administration time of 10 to 11 pm. Reports of post-plerixafor anaphylactic reactions mandated labeling change by the Food and Drug Administration with recommendation of monitoring patients after administration. Based on data suggesting sustained plerixafor activity at 18 hours, we changed our administration time to 4 pm at our center.

Objective: The objective of this study is to compare the stem cell collection efficiency before and after the practice change at our institution.

Methods: A retrospective chart review for patients with multiple myeloma, Hodgkin lymphoma, and non-Hodgkin lymphoma who received a plerixafor-containing mobilization regimen was conducted. The primary end point was the percentage of patients achieving the minimal CD34⁺ cell goal in ⩽2 apheresis days. The secondary end points included the percentage of patients achieving the preferred CD34⁺ cell goal in ⩽2 apheresis days, days of apheresis, total CD34⁺ cells Collected, and engraftment time.

Results: A total of 208 patients (4 pm group n = 68, 10 pm group n = 140) with multiple myeloma (n = 112), Hodgkin lymphoma (n = 10), and non-Hodgkin lymphoma (n = 86) were included in the analysis. About 91% and 89% (P = .804) of the patients in the 4 and 10 pm groups, respectively, collected minimum cell dose. Preferred CD34⁺ cell goal was achieved in 57% and 53% of patients in the 4 and 10 pm groups, respectively.

Conclusions: Late afternoon administration of plerixafor provides efficient stem cell mobilization.