A randomized controlled clinical trial to determine the optimum duration of G-CSF priming prior to BM stem cell harvesting

Background: Harvesting of hemopoietic stem cells (HSC) from G-CSF-primed BM for autologous transplantation is an alternative to collection of unprimed BM or G-CSF-primed peripheral blood (PB). However, the optimum number of days of G-CSF administration for this purpose is unknown. We set out to determine whether cell yields could be optimized by varying the number of days of G-CSF administration prior to BM stem cell harvesting. Methods: We conducted a randomized controlled single-centertrial of 6 days (the standard) vs. 4 days of G-CSF administration and compared yields of total nucleated cells (TNC), CD34+ HSC and CFU-GM cells per kilogram patient body weight. Statistical analysis was by Student's t-test. Results: Twenty-four patients were enrolled; 13 received 6 days and 11 received 4 days of G-CSF administration. Analysis of the first harvest aspirate showed higher proportions of CD34+ HSC (P = 0.02) and CFU-GM (P = 0.03) in the 4-day group. For the 6-day and 4-day groups, respectively, the median yield of TNC/kg was 6.5 × 108 and 5.4 × 108 (P = 0.28), of CD34+ cells/kg 0.56 ×106 and 0.98 × 106 (P = 0.04) and of CFU-GM cells/kg 1.66 × 105 and 1.55 × 105 (P = 0.75). Discussion: These results suggest that by 6 days the HSC-stimulating effect of G-CSF has passed its peak and that 4 days should be adopted as the standard for G-CSF priming prior to BM stem cell harvesting for autologous transplantation.