COVID-19 PANDEMIC AND ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION: A SINGLE CENTER REAPPRAISAL

ABSTRACT COVID-19 pandemic has deeply modified the complex logistic process underlying allogeneic hematopoietic stem cell (HSC) transplant practices. We compared data relative to allogeneic transplants carried out from 2018 at our center, before (n=167) or during the pandemic (n=45). We examined patient's characteristics, donor and graft types, cell doses and main transplant outcomes. Moreover, we appraised the rise of costs attributable to COVID-19-related additional procedures, as well as the risk for adverse events that these procedures conveyed to grafts or recipients. Overall, the number of transplants did not decrease during pandemic, whereas patients at high relapse risk were prioritized. Transplants were mainly from matched unrelated donors, with a significant decrease of haploidentical related donors. Moreover, the use of bone marrow as a graft for haplo-transplant was almost abandoned. Cryopreservation was introduced for all related and unrelated apheresis products, with a median storage time of 20 days. Notably, transplant outcomes (engraftment, acute graft versus host disease and non-relapse mortality) with cryopreserved products were comparable to those with fresh products. Considering that the emergency situation may persist for months, to cryopreserve allogeneic grafts can offer a lifesaving opportunity to patients whose allogeneic transplant cannot be postponed after the end of the COVID-19 pandemic.