A randomized study of multi-day infusion of autologous peripheral blood progenitor cells

Peripheral blood progenitor cells (PBPC) are increasingly used as the source of stem cells in both the autologous and allogeneic settings. Based on previous early non-randomized studies reporting enhanced engraftment following fractionated autologous PBPC infusion, some centers and study groups infuse PBPC over 3 days. To study the possible benefit of multiple day PBPC infusion, 60 patients receiving high-dose chemotherapy and autologous progenitor cell transplantation (ABMT) were randomized to receive their PBPC divided over 1, 2 or 3 days. Stem cells were mobilized with G-CSF 5 microg/kg for 7 days and PBPC were collected on days 5-7. Patients received daily G-CSF 5 microg/kg i.v. over 30 min beginning 4 h after the infusion of the first aliquot of PBPCs. Toxicity was similar for the 1, 2 and 3 day infusion groups. The median time to achieve 500 neutrophils/mm3 was 10, 11 and 11 days in the groups receiving PBPCs over 1, 2 or 3 days, respectively. The median time to achieve a platelet count of 20 x 10(9)/l was 11 days for the group receiving their cells as a single infusion and 12 days in the other two groups. We conclude that expanding PBPC infusion over 2 or 3 days does not enhance engraftment or reduce toxicity.