Peripheral blood stem cell mobilization with pegfilgrastim compared to filgrastim in children and young adults with malignancies.

BACKGROUND

Pegfilgrastim, the long acting agent of rh-GCSF, has been shown to be as effective as Filgrastim in children undergoing cytotoxic chemotherapy by reducing the duration of neutropenia. Recent studies in adults have also shown that Pegfilgrastim is effective to mobilize CD34+ stem cells, resulting in earlier peripheral stem cell collections (PSCC). The aim of the study was to compare the efficacy of Pegfilgrastim with Filgrastim for CD34+ stem cell mobilization in children.

PROCEDURE

Three groups of patients were compared: Group 1: six patients with Ewing Sarcoma stimulated with Filgrastim; Group 2: five patients with Ewing Sarcoma, Ependymoma, and Neuroblastoma; Group 3: four patients with relapsed neoplasm. Patients of Group 2 and 3 were stimulated with Pegfilgrastim followed by peripheral stem cell collection. Two patients in Group 3 needed further cytokine stimulation with Filgrastim combined with stem cell factor, Ancestim.

RESULTS

In Groups 1-3, a median of 4, 3, and 3 PSCC between day 12-24, 6-13, and 8-30 were performed, yielding a median of 14.2, 24.0, and 10.3 x 10(6) CD34+ stem cells/kg BW, respectively.

CONCLUSIONS

Group 2 data show that stem cell mobilization with Pegfilgrastim in children when performed during primary or without previous long lasting chemotherapy seems to produce earlier CD34+ peaks and better CD34+ yields than in Group 1. CD34+ cell mobilization with Pegfilgrastim in Group 3-patients with previous long lasting chemotherapy was possible.