Peripheral blood stem cells (PBSC) used for allogenic transplantation (SCT) are collected by apheresis after donors treatment with G-CSF. It was studied whether collection on the 4th day instead of the 5th day after initiation of G-CSF treatment might be feasible, which reduces exposure to the drug and potential adverse effects associated with its administration in healthy donors.
To compare feasibility and effectiveness of Day 4 mobilization versus Day 5 in allogeneic stem cell donors.
We performed a restrospective single-center study. Stem cell donors were stimulated with subcutaneous injections of 5 μg G-CSF (filgrastim)/kg body weight (BW) twice daily. The CD34+ target was 5 × 106/kg recipient BW for haploidentical SCT (haplo-SCT) and 4 × 106/kg for both HLA-matched related donors (MRD) and unrelated donors (UD) SCT. PBSC collection was performed with the Spectra Optia. Mobilization on Day 5 was performed during 2016-2017 and on Day 4 since 2018. CD34+ cells were counted in pre and postapheresis peripheral blood and product samples respectively by flow cytometry using a single-platform assay. We applied means of descriptive statistics, χ2 test and Student's t-test for comparisons, regression analysis and Pearson correlation coefficient (IBM SPSS Statistics 22).
We analyzed 87 PBSC allogeneic procedures: 45 (51.7%) performed on the 4th day of mobilization and 42 (48.3%) on the 5th day. Both apheresis groups were comparable with regard to donor and recipient characteristics (table 1). Distribution of SCT types was similar in both groups: MRD 23 (51.1%) vs 17 (40.5%), UD 8 (17.8%) vs 10 (23.8%) and haplo 14 (31.1%) vs 15 (35.7%) respectively for Day 4 and Day 5 (p = 0.59). We found no differences in G-CSF-related adverse effects nor in apheresis collection procedures between both groups. G-CSF global treatment price difference between 4 days and 5 days was 1,355€ (11,360€ vs 12,715€; p < 0.001). Correlation between PBSC pre-apheresis and post-apheresis sample CD34+ cell count (/μl) of each group is presented in Figure 1. The CD34+ cells count in post-apheresis products did not differ between Day 4 and Day 5 groups (table 1). Donors who failed the CD34+ target quantity on first apheresis (7/45 of Day 4 and 6/42 of Day 5) reached it on a second procedure; no donor received plerixafor. Main charasteristics are summarized in table 1.
Our results suggest that apheresis on the 4th day of low-dose G-CSF-induced mobilization in allogeneic stem cell donors is as feasible and effective as collection on Day 5, reducing G-CSF exposure to healthy donors and global costs.