Plerixafor stem cell mobilization in Japanese children: A post-marketing study

Peripheral blood stem cell harvesting in young children weighing less than 15 kg

Autologous peripheral blood stem cell (PBSC) transplantation is crucial in pediatric cancer treatment, and tandem transplantation is beneficial in certain malignancies. Collecting PBSCs in small children with low body weight is challenging. We retrospectively analyzed data of pediatric cancer patients weighing <15 kg who underwent autologous PBSC harvesting in our hospital. Collections were performed in the pediatric intensive care unit over 2 or 3 consecutive days, to harvest sufficient stem cells (goal ≥2 × 106 CD34+ cells/kg per apheresate). From April 2006 to August 2021, we performed 129 collections after 50 mobilizations in 40 patients, with a median age of 1.9 (range, 0.6-5.6) years and a body weight of 11.0 (range, 6.6-14.7) kg. The median CD34+ cells in each apheresate were 4.2 (range, 0.01-40.13) × 106/kg. 78% and 56% of mobilizations achieved sufficient cell dose for single or tandem transplantation, respectively, without additional aliquoting. The preapheresis hematopoietic progenitor cell (HPC) count was highly correlated with the CD34+ cell yield in the apheresate (r = 0.555, P < 0.001). Granulocyte colony-stimulating factor alone was not effective for mobilization in children ≥2 years of age, even without radiation exposure. By combining the preapheresis HPC count ≥20/μL and the 3 significant host factors, including age <2 years, no radiation exposure and use of chemotherapy, the prediction rate of goal achievement was increased (area under the curve 0.787).

Efficacy and safety of plerixafor in pediatric cancer patients undergoing peripheral blood stem cell harvest for autologous hematopoietic stem cell transplant

Plerixafor for peripheral blood hematopoietic stem cell (PB HSC) mobilization in children undergoing autologous hematopoietic stem cell transplantation is primarily used following failure of the initial mobilization attempt. Data on plerixafor use in pediatric patients are limited. This retrospective study conducted at a single tertiary care center in India, details the efficacy and safety of plerixafor for 10 children with relapsed/refractory solid tumors or lymphomas. High risk neuroblastomas (HR NB) underwent autologous HSCT as part of consolidation. Plerixafor was administered at a dose of 240 μg/kg body weight of the recipient, subcutaneously, approximately 11-12 h prior to harvest. Ten patients (eight males, two females), with a median age of 8 years (range 2-18 years), received plerixafor prior to PB HSC harvest. All patients were administered granulocyte colony stimulating factor (GCSF) before the administration of plerixafor. The median CD 34 count for all patients pre-plerixafor was 29/μL, nine patients exhibited higher CD 34 post plerixafor (median of 148/μL). In nine patients, the values of the CD 34 count and total leukocyte count (TLC) of the harvested product were available, and in all cases, we achieved a good yield. All patients in this study were heavily chemotherapy pre-treated, and the use of plerixafor resulted in a satisfactory yield of peripheral blood stem cells. No side effects were observed.