Abstract
The COVID-19 pandemic brought along many changes, including clinical practice changes to allogenic hematopoietic cell transplantation (HSCT). Prior to the pandemic, cryopreservation (a cooling process that preserves organelles, cells, tissue, or any other biological constructs) was commonly performed on autologous and cord blood-derived stem cell products. However allogenic products traditionally have been administered fresh due to the theoretical concern regarding the detrimental effect of freezing and thawing on hematopoietic stem and progenitor cells. During the pandemic there was concern regarding infection of either the donor and or recipient which may delay transplant. There were also new restrictions on transportation and handling of cellular products. Therefore, in March 2020, the National Marrow Donor Program recommended that all grafts be cryopreserved to minimize these risks.
Although multiple studies have shown no significant difference in time to engraftment, relapse, non-relapse mortality or survival in adults when receiving cryopreserved bone marrow products compared to fresh products, literature is scarce regarding the impact of cryopreservation on pediatric HSCT.
The primary objective of this study is to examine the effects of cryopreserved stem cell product on overall survival compared to fresh stem cell product in allogenic transplants. Secondary objects include examining the effects of cryopreserved stem cell product on time to engraftment, development of acute graft vs host disease (GVHD) and/or chronic GVHD, incidence of relapse, incidence of graft failure and longitudinal immune reconstitution.
Retrospective chart review conducted, looking at allogenic transplants completed at Phoenix Children's Hospital between January 1st, 2016 – March 31st, 2023.
A total of 187 first time HSCT were conducted during the above timeframe. Of those 105 HSCT utilized fresh stem cell products, whereas 82 transplants utilized cryopreserved stem cell product. Our patient population median age was 10 years and 5 months (2 months – 29 years and 7 months). 91 malignant and 96 non-malignant HSCT were performed. 110 patients received a myeloablative prep regimen (55% were fresh vs 45% were cryopreserved). 74 patients received a reduced intensity regimen (55% were fresh vs 45% were cryopreserved). 3 patients’ regimens were unknown. Of the fresh product group 86% of patients are currently alive, verses 83% from the cryopreserved group.
This would be the 1st study exclusively looking at the impact of cryopreservation compared to fresh products on pediatric HSCT outcomes. Our analysis is currently ongoing, however preliminary data points towards no difference in overall survival, mirroring the adult data.