Clinical Impact of Cryopreservation of Allogeneic Hematopoietic Cell Grafts During the Onset of the COVID-19 Pandemic.

ABSTRACT

At the onset of the COVID-19 pandemic, the National Marrow Donor Program mandated the cryopreservation of hematopoietic cell grafts from volunteer unrelated donors due to numerous patient and donor safety concerns and logistical hurdles. Using the Center for International Blood and Marrow Transplant Research (CIBMTR) outcomes database, we report the impact of cryopreservation on overall survival (OS) and other outcomes within one year following hematopoietic cell transplantation (HCT). We analyzed 1,543 recipients of cryopreserved allografts receiving HCT at US centers during the first 6-months of the pandemic and compared them to 2,499 recipients of fresh allografts during the same 6-month period in 2019. On multivariable regression analysis, we observed no difference in OS (HR, 1.12; 95% CI 0.98-1.28; P=0.09), non-relapse mortality (HR, 1.01; 95% CI 0.84-1.22; P=0.89), graft-versus-host disease (GVHD), or GVHD-free, relapse-free survival (HR 1.03; 95% CI 0.93-1.14; P=0.58) in recipients of cryopreserved versus fresh allografts. Disease-free survival (DFS) was lower in the cryopreserved group (HR, 1.18; 95% CI 1.05-1.33; P=0.006) due to a higher risk of relapse (HR, 1.21; 95% CI 1.04-1.41; P=0.01). Primary graft failure was higher with cryopreservation (OR 1.48; 95% CI 1.10-2.00; P=0.01) and the risk of chronic GVHD was lower (HR, 0.65; 95% CI 0.50-0.84; P=0.001). In conclusion, while there was no negative impact of cryopreservation on OS, relapse was higher and DFS was lower. Fresh grafts are recommended as the pandemic related logistical hurdles resolve. Cryopreservation should be considered an option for patients when fresh grafts are not feasible.