NON Cryopreserved Hematopoietic STEM CELLS to Autograft Patients with Lymphomas: A PAIR Matched Analysis Comparing a Single Center Experience to the Use of Cryopreserved STEM CELLS Reported to the EBMT Registry

Introduction:

Around fifty thousand autologous stem cell transplantations are done each year worldwide, using cryopreserved peripheral blood stem cells (PBSC). Cryopreservation is time consuming and expensive. Since 2007, several retrospective studies have shown that PBSC can be stored at 4Dg C for two to three days, allowing autologous stem cell transplantation (ASCT) in patients with multiple myeloma receiving high dose melphalan. Data with non-cryopreserved PBSC in patients autografted for lymphoma following longer preconditioning regimens are limited. In addition, there has been no controlled comparison able to possibly detect unforeseen differences.

Patients and methods:

We compared outcomes of 94 consecutive adult patients with lymphomas (66 with Hodgkin Lymphoma) autografted in our department in Oran (Algeria), using PBSC stored at 4 dg C, from 2009 to 2018 with patients receiving cryopreserved stem cells reported to the EBMT registry. Patient's autografted in Oran were matched with patients receiving cryopreserved PBSC in the registry (4 controls per Oran Patient).

Results:

Neutrophil engraftment was significantly faster with cryopreserved PBSC (p= 0.003): by day 10, only 17% of patients receiving non-cryopreserved PBSC engrafted versus 48% for cryopreserved PBSC. Likewise, platelet recovery to 20 000/mm³ was significantly faster in patients receiving cryopreserved PBSC (p=0.01). However, all patients in both groups had recovered by day 20. There were no significant differences in Non Relapse Mortality (9% versus 7%; p=0.4), Relapse Incidence (22% versus 32%; p=0.13), Progression Free Survival (70% versus 61%; 0.4) or Overall Survival (85% versus 75%; p=0.3).

Conclusion:

This analysis suggests that, in patients with lymphomas receiving pretransplant regimens such as the BEAM, PBSC stored at 4dg C for up to six days can be used safely in centers with no cryopreservation facility. The kinetics of recovery of hematopoiesis however did show a significant, albeit small, delay of engraftment for both neutrophils and platelets, which favors the use of cryopreservation if available.