The efficacy of pegfilgrastim ± chemotherapy for mobilizing stem cells in patients with solid tumours was assessed. In cycle 0, a 14-day prechemotherapy cycle, patients (N=61) were randomized open-label to single doses of pegfilgrastim (6, 12 or 18mg) on day 1, or daily filgrastim (10 μg/kg) for ≤7 days. Mean peak peripheral CD34+ cell counts increased with pegfilgrastim dose, but were significantly higher than filgrastim only at the 18mg dose (10.17 vs 4.96 × 104/ml;P=0.014). In the clinically relevant period of days 3-7, both 12 and 18mg pegfilgrastim doses produced significantly higher peak CD34+ counts (8.18 and 9.96 vs 4.51 × 104/ml for filgrastim;P=0.034 and 0.006). In cycle 1, patients received carboplatin/paclitaxel on day 1, followed from day 2 by pegfilgrastim 6-18mg or daily filgrastim (5 μg/ kg/day for ≤14 days) as per randomization in cycle 0. There were no significant differences in mean peak CD34+ count between pegfilgrastim and filgrastim, but there was an advantage for pegfilgrastim 18mg in the relevant period of days 7-12 (3.14 vs 1.19 × 104/ml;P=0.043). A single pegfilgrastim dose (≥6mg) could be substituted for daily filgrastim in cytokine-only peripheral CD34+ cell mobilization.
Bone Marrow Transplantation (2009) 43, 927-934; doi:10.1038/bmt.2008.411; published online 26 January 2009