Feasibility and safety of peripheral blood stem cell collection in children with extremely low body weight: A single center study.

Background: Apheresis cell collections (HPC(A)) are used for hematopoietic stem cell transplantation and gene therapy; however, they present unique challenges in children with extremely low body weight (≤10 kg). We aimed to investigate the feasibility and safety of HPC(A) in these patients.

Study design and methods: This retrospective single-center study reviewed HPC(A) collections at one pediatric center between 2017 and 2024 in patients ≤10 kg. Data included collection parameters, anticoagulant type, and demographics. Feasibility was assessed on target CD34+ count. Safety was evaluated on the incidence and severity of adverse events (AEs). Descriptive statistics and comparative tests (Wilcoxon rank sum, Welch t-test) were applied.

Results: Nineteen patients underwent 20 autologous collections with an average patient weight of 7.70 kg. Central venous access was required in all, with 90% inpatient collections. Average patient total blood volume and volume processed were 557 and 2523 mL. Collections used acid citrate dextrose, solution A (ACD-A) only (50%) or ACD-A + heparin (50%). Run times between the two were not significantly different, but the inlet flow rate was significantly higher in the ACD-A + heparin group (p = .017). 90% of patients received granulocyte colony-stimulating factor only, with the remainder also receiving plerixafor. Average minimum-target dose was 12.8-20.5 million CD34/kg. The target dose was achieved on Day 1 of collection in 19 collections (95%), with the target achieved on Day 2 in the single remaining patient. There was one incidence of hypocalcemia with no serious AEs. Average collection efficiency (CE)1 and CE2 were 59% and 49%.

Discussion: HPC(A) is feasible and safe in patients ≤10 kg, including with ACD-A + heparin anticoagulation, supporting broader application in this population.