Successful mobilization with AMD3100 and filgrastim with engraftment of autologous peripheral blood stem cells in a heavily pretreated pediatric patient with recurrent Burkitt lymphoma

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

BACKGROUND

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).

METHODS

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.

RESULTS

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 5 days (range 3-11 days) in the heavily pretreated group and 5 days (range 3-13 days) in the not heavily pretreated group (p = .55). The number of harvest days was 2 days (range 1-5 days) in the heavily pretreated group and 1 day (range 1-4 days) 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.

CONCLUSIONS

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.

Successful mobilization using a combination of plerixafor and G-CSF in pediatric patients who failed previous chemomobilization with G-CSF alone and possible complications of the treatment

Peripheral blood stem cell (PBSC) mobilization, which uses plerixafor (AMD 3100), a newly developed specific inhibitor of the CXCR4 receptor, in combination with granulocyte-colony stimulating factor(G-CSF), has been shown to enhance the stem cell mobilization in adult patients, but pediatric data are scarce. We documented our experience with this drug in 6 Korean pediatric patients who had failed in chemomobilization, using G-CSF, alone. All patients were mobilized CD34⁺ cells (median, 11.08 × 10⁶/kg: range, 6.34-28.97 × 10⁶/kg) successfully within 2 to 3 cycles of apheresis, without complications. A total of 7 autologous transplantations were performed, including 1 tandem transplantation. However, 2 patients with brain tumors showed severe pulmonary complications, including spontaneous pneumomediastinum. This is the first study of PBSC mobilization with plerixafor in Asian pediatric patients. Furthermore our study suggests that mobilization with plerixafor may be effective in Korean pediatric patients, who have previously been heavily treated and have failed PBSC mobilization with classical chemomobilization, using G-CSF. However, further studies are needed to examine the possible complications of autologous transplantation, using a mobilized plerixafor product in children.

Plerixafor plus granulocyte-colony stimulating factor for autologous hematopoietic stem cell mobilization in patients with metastatic neuroblastoma

Current therapies for high-risk neuroblastoma (NB) necessitate the availability of several aliquots of autologous peripheral blood stem cells to reverse-associated myelosuppression. Priming with the CXCR4 inhibitor plerixafor plus G-CSF was associated with successful stem cell harvest in 5/7 heavily prior-treated patients with stage 4 NB who had previously failed G-CSF priming. Minimal residual disease was not detected in harvested cells from any patient despite the presence of disease in bone/bone marrow in 6/7. Hematopoietic reconstitution was achieved in all three patients receiving plerixafor-primed stem cells after myeloablative therapy. Plerixafor is an effective and safe agent for stem cell collection in patients with NB.

Priming of hematopoietic progenitor cells by plerixafor and filgrastim in children with previous failure of mobilization with chemotherapy and/or cytokine treatment

Plerixafor has been recently approved by the European Medicines Agency for adult patients who have failed other mobilization strategies. Experience in children, however, is extremely limited. We describe the experience of the use of this drug in 8 children under a compassionate-use program in 3 Italian and 2 Spanish centers. Plerixafor was generally well tolerated; only 2 of 8 children reported adverse effects, and these were mild in intensity. Peripheral blood progenitor cell priming was improved with plerixafor in 6 of 8 patients. In the remaining 2 patients, the target CD34+ cell count was below the target of 2 × 10(6) cells/kg, although in these patients cell counts before collection were good enough for leukapheresis. Plerixafor, therefore seems to be safe and effective for peripheral blood progenitor cell mobilization in children. Adverse events were comparable with those described with filgrastim alone.