Mobilization and harvesting of peripheral blood stem cells: Randomized evaluations of different doses of filgrastim

Abstract

The effects of different doses of filgrastim on yields of CD34+ peripheral blood stem cells were evaluated in patients with breast cancer. 55 were randomized to receive filgrastim 10, 20, 30 or 40 μg/kg/d with more CD34+ cells/kg/apheresis harvested after the three highest dose levels. 35 additional patients were randomized to receive 10 or 30 μg/kg. The median number of CD34+ cells collected after 10 μg/kg (n= 31) was 0.7x 106/kg/apheresis (range 0.1-4.4) as compared to 1.2 (range 0.1-6.8) after 30μg/kg (n=32) (P=0.04). Among patients randomized to 10 v 30μg/kg, more (50%) achieved ≤ 5.0x106 CD34+ cells/kg and less aphereses were required to achieve ≤ 2.5 x 106 CD34+ cells/kg after the higher dose (P = 0.04). In multivariate analyses, patients receiving 10μg/kg (n=31) had lower yields of CD34+ cells (P= 0.026) and had a 3.3-fold increase in the probability of not achieving ≤ 5.0 x 106 CD34+ cells/kg as compared to patients receiving 20- 40μg/kg (n=59). Patients who had received radiation had a 2·9-fold probability of not achieving ≤2·5x 106 CD34+ cells/kg. These data suggest that, in patients with good marrow reserves, doses of filgrastim > 10μg/kg/d mobilized more CD34+ cells and may be useful when high numbers of CD34+ cells are desired.