Mobilization with high-dose granulocyte colony-stimulating factor alone at 12 μg/kg twice a day in high-risk pediatric patients: A retrospective analysis of the experience in a single center.

Introduction: Mobilization regimes in pediatric patients at high risk for poor mobilization are not standardized across different institutions. We present a retrospective analysis of our experience with a high-dose granulocyte colony-stimulating factor (G-CSF) regime of 12 μg/Kg per body weight (BW) twice a day for 4 days used in high-risk patients.

Material And Methods: We report the results of all pediatric patients mobilized with high-dose G-CSF between January 1999 and February 2021 in our center. A successful mobilization was defined as a peripheral blood (PB) CD34 cell count of ≥10 CD34 cells/μl on the fifth day of mobilization immediately before leukapheresis. A minimum cell yield of ≥2 × 10 CD34 cells/Kg of BW was required for a successful collection.

Results: Of the 262 patients included in the analysis, mobilization failure was found in 27 (10.3%). In a univariate analysis, this was associated with age, weight, baseline diagnosis, and having undergone a previous mobilization cycle, the latter being the only factor that remained significantly associated in a multivariate analysis (P = 0.03). The 54 patients (20.6%) did not reach the minimum required CD34 cell yield. 50.4% of the patients reported adverse events (AEs) during the mobilization period, and 23 (9.1%) reported 3 or more concomitant AEs. However, all of them were mild and did not affect the mobilization schedule.

Conclusions: Although most high-risk pediatric patients are successfully mobilized with the high-dose G-CSF regime, this approach does not salvage all of them and significantly increases the presence of AEs in comparison to standard-dose regimes.