Effect of filgrastim priming dose on peripheral blood progenitor cell yield, engraftment, and survival in women undergoing high dose chemotherapy for breast cancer

To investigate the effect of priming dose of filgrastim (G-CSF) on clinical parameters in women undergoing stem cell transplant for breast cancer, patients were randomized to receive 5 or 10μg/kg G-CSF on days 1-7 with 10 liter stem cell collections on days 5,6,7. No chemotherapy priming was used. Apheresis product was analyzed for MNC/kg, WBC/kg, and CFU-GM. After hormone recruitment, patients were treated as follows; cyclophosphamide 7.2g/m2, etoposide 1.6gm/m2, and carboplatin 1.6gm/m2 days -6 to -2. Patients received G-CSF 10μg/kg/d following stem cell infusion until absolute neutrophil count (ANC) > 1000 for 3 days. Tamoxifen was started on d+15. Results: Thirty-six patients were enrolled. Patients were stage IV with no evidence of disease (n=31), stage IIIB (n=4), or bilateral stage II/III (n=1). Thirty-five patients had stem cells collected and 34 are evaluable for engraftment. Collection and engraftment data are shown below (median follow up=72 months): 5μg/kg 10μg/kg p-value Total MNC/kg 7.7×108 10.9×108 0.003 First Day CFU-GM/kg 1.0×105 3.8×105 0.013 Total CFU-GM/kg 4.2×105 7.7×105 0.221 Length of Stay 28 days 25 days 0.599 ANC≥500 9.9 days 9.5 days 0.273 Platelet≤20,000 20.3 days 18.2 days 0.607 Median overall survival-all pts 22 months 42 months 0.026 Median overall survival-stage IV pts 23 months 48 months 0.016 There was no difference in use of red blood cell or platelet transfusions. Known prognostic markers were similar between the two groups. Conclusion: A higher number of MNC/kg and WBC/kg were obtained with 10μng/kg G-CSF priming in women undergoing stem cell transplant for breast cancer. Significantly higher CFU-GM were collected on the first day in the 10μg/kg cohort, but the totals for 3 days did not differ, nor did engraftment parameters. Patients who received 10μg/kg G-CSF for priming had improved survival. The mechanism underlying this finding is unknown.

Duke Scholars

Author Stephen L. George Biostatistics & Bioinformatics, Division of Biostatistics