Pediatric Hematopoietic Progenitor Cell Collection and Transplant: Does Pegfilgrastim Represent Progress?.

The particular technical challenges of apheresis in children require the highest quality of stem cell mobilisation. To date, G-CSF remains the reference. The arrival of pegfilgrastim (pegf) theoretically allows the maintenance of an elevated and constant serum level of G-CSF after only one injection. DESIGN: eleven children (2–16 yrs) undergoing chemotherapy for malignancy were consecutively included in a prospective pilot study. Mobilization consisted of one sc injection of 300 μg/kg pegf in haematological steady state. Apheresis was begun once the value of 20 CD34+/μl cells was reached in the blood, or at day 4 after pegf administration. RESULTS: at first apheresis the mean CD34+ cell, mononuclear cell and polynuclear blood counts were respectively 98/μl (12–353), 7.26×109/l (1.0–9.5) and 39.3×109/l (4.6–57.3). The CD34+cell peak level was obtained on day 3 after injection (3–5). The first standard apheresis (less than 3 patient blood volumes) allowed the harvest of more than 5×106 CD34+ cells in 9/11 pts, the median CD34+ cell harvest being 13.5×106/kg (range 1.6–36). On day six after injection, the median ANC was 13.6×109/l. These results were compared to 3 historical prospective cohorts of children who received non-conjugated G-CSF at 10, 20 or 2×12 μg/kg/j, respectively. The four cohorts were not different for age, weight, diagnosis and rounds of chemotherapy. Mobilisation with pegf was more efficient than with G-CSF at 10 μg/kg/d (p Tolerance: 8 pts had an elevation of LDH, 3 a hyperuricemia respectively up to 2 times and 1.5 times the upper limit. After reinfusion, polynuclear recovery (ANC>500/μl) was obtained after (median) 11.5 days (11–13); platelet recovery (>20 G/l) was reached on median day 17 (12–20). CONCLUSION: the combination of predictable mobilisation kinetics similar to those of non-pegylated G-CSF, a better acceptance profile together with an efficiency which appears to be at least as good, seems to represent progress in stem cell mobilisation in children. However, sustained blood WBC levels indicating that hematopoiesis has not returned to steady state necessitates a slight delay (at least 7 days) in resuming the chemotherapy program.