Efficacy and toxicity of a high-dose G-CSF schedule for peripheral blood progenitor cell mobilization in healthy donors.

An important issue in allogeneic peripheral blood progenitor cell transplantation is the optimization of the regimen of mobilization of progenitor cells from normal donors. It has been shown that for G-CSF doses up to 10 microg/kg/day, a dose-response relationship exists for the degree of progenitor cell mobilization. Formal comparisons with doses higher than 10 microg/kg/day, however, have not been reported. The aim of this study was to compare the mobilization and collection results of two different G-CSF (Filgrastim) schedules: 10 microg/kg/12 h (n = 20; group A) vs 10 microg/kg/24 h (n = 20; group B). Apheresis sessions were started on day 5 (after 4 days of G-CSF). Adverse events consisted of bone pain, headache, and fatigue which required treatment with acetaminophen +/- codeine in both donor groups. Discontinuation of G-CSF administration for intolerable side-effects was not necessary in any case. The increase in peripheral leukocyte and lymphocyte counts x 109/l on day 5 was higher in group A (56.2 (37.1-75.2) and 4.4 (2. 1-14.6), respectively) than in group B (27.5 (13.2-53.9) and 2.6 (1. 9-5.1), respectively) (P < 0.0001 and P = 0.008). Platelets x 109/l decreased in group A from 228 (161-286) before G-CSF administration to 207 (155-328) on day 5 (P = 0.03), whereas no change was observed in group B. Following the first apheresis, a significant decrease in platelet count was observed with both G-CSF schedules without any differences between groups. The number x 106/kg of both nucleated and CD34+ cells collected after the first apheresis session was higher in group A (672 (462-992) and 5.9 (3.4-10.4), respectively) than in group B (427 (319-608) and 3.1 (1.1-6.8), respectively) (P = 0.0003 in both cases). The median number of CD3+cells x 106/kg collected after one apheresis session was similar with both G-CSF schedules (212 (91-430) in group A and 170 (110-291) in group B) (P = NS). In conclusion, the schedule of 10 microg/kg/12 h was well tolerated and resulted in the collection of a higher number of progenitor cells than 10 microg/kg/24 h without increasing the T cell content. This approach could avoid the donor having to undergo a second apheresis, and facilitate further graft manipulation.