The use of plerixafor in hematopoietic progenitor cell collection in pediatric patients: a single center experience

Background aims. Plerixafor was recently approved for use in combination with granulocyte – colony-stimulating factor (G-CSF) for hematopoietic progenitor cell (HPC) collection by apheresis in adults with multiple myeloma (MM) or nonHodgkin lymphoma (NHL). However, its effi cacy in pediatric patients is not well-studied; thus, we report on our institutional experience with this population. Methods. A retrospective observational analysis was performed using both stem cell-processing laboratory information as well as apheresis charts and medical records on all pediatric patients who received plerixafor as part of the mobilization regimen between December 2006 and December 2010. The primary outcome was collection yield. Secondary outcomes included the ability to undergo autologous hematopoietic stem cell transplantation (auto-HSCT) and engraftment status. Results. Eighteen HPC collections by apheresis representing seven mobilization courses were performed on fipediatric patients with poor mobilization status (three males, two females; median age 14 years). Median pre-harvest peripheral blood CD34 cell (PB CD34 ) count was 6.88/ μ L. A strong correlation between pre-harvest PB CD34 count and collection yield was observed. Median total collection yield was 2.26 10 6 CD34 cells/ kg. Four patients achieved a minimum collection of 2 10 6 CD34 cells/kg. Three patients underwent auto-HSCT with a median neutrophil and platelet engraftment of 12 and 34 days, respectively. No major adverse events with plerixafor administration or apheresis collections were reported. Conclusions. Plerixafor in combination with G-CSF is a safe and potentially helpful mobilization agent in poor mobilizers. Further studies should be done to evaluate the true effi cacy of plerixafor in the pediatric population.