Recruiting or enrolling participants has halted and will not resume

Hypothesis: pegfilgrastim at 300 µg/kg in hematological steady state provides an efficient stem cell mobilization in children with malignancies

Design: phase 2 study.

Judgment criterion: percentage of children achieving at least 5x10e6 CD34 cells with a standard apheresis (less than 2 blood volume processed)

Patients: consecutively referred for HSC mobilization. At least 17 days after the previous chemotherapy. No hematological growth factor during the 8 previous days.

Mobilization: one sc injection of 300 µg/kg pegfilgrastim (Neulasta, Amgen)

Evaluation during the study: CD34 circulating cells from day 2 to day 7 ; AE recording

Judgment criterion: percentage of children achieving at least 5x10e6 CD34 cells with a standard apheresis (less than 2 blood volume processed)

Analysis: sequential Bayesian study

Inclusion Criteria:

• 0 to 18 years
• solid malignancy
• Lansky score >70%
• more than 17 days since the beginning of the last chemotherapy cycle
• absolute neutrophil count (ANC) greater than 1×109/l
• no administration of any hematopoietic growth factor in the previous 8 days

Exclusion Criteria:

• clinical or biological conditions precluding the mobilization or collection procedure