Single-center results reporting improved hematopoietic stem cell mobilization success in pediatric and young adult patients with solid tumors and lymphoma.

Abstract

High-dose chemotherapy with autologous hematopoietic stem cell transplantation (auto-HSCT) is an established treatment for pediatric and young adult patients with solid tumors and lymphomas. Plerixafor is a CXC chemokine receptor type 4 (CXCR4) antagonist that can be used with granulocyte colony stimulating factor (G-CSF) to amplify the mobilization of hematopoietic stem cells (HSCs). We performed a retrospective analysis of 167 pediatric solid tumor and lymphoma patients from January 2010 to July 2020 in whom HSCs were mobilized using G-CSF alone or with plerixafor. Thirteen heavily pretreated patients (33.3%) required twice-daily dosing of G-CSF compared to five patients (3.9%) in the not heavily pretreated group (p=.0005). Fourteen heavily pretreated patients (35.9%) required plerixafor compared to four patients (3.1%) in the comparison cohort (p=.0002). The number of mobilization days was similar between both cohorts, with 5days (range 3-11days) in the heavily pretreated group and 5days (range 3-13days) in the not heavily pretreated group (p=.55). The number of harvest days was 2days (range 1-5days) in the heavily pretreated group and 1day (range 1-4days) in the not heavily pretreated group (p=.0025). The final cluster of differentiation (CD)34+ /kilogram (kg) count was 9.52 × 106 /kg among heavily pretreated patients compared to 34.99 × 106 /kg CD34+ cells in the comparison group (p<.0001). Three heavily pretreated patients (7.7%) failed HSC mobilization. Patients at the highest risk for poor HSC mobilization can be successfully treated with more frequent G-CSF dosing or G-CSF with plerixafor in a large majority of cases.