A case-control study on cryopreserved versus non-cryopreserved strategies for autologous hematopoietic cell transplantation in multiple myeloma

Background: Autologous hematopoietic cell transplantation (aHCT) is a standard treatment for Multiple Myeloma (MM). The classic practice is with cryopreservation of the peripheral blood stem cells (PBSC) in the period from collection to infusion, but non-cryopreserved storage at 4oC has demonstrated to be feasible and safe. Methods: Here we present a retrospective, case-control study comparing the outcomes in terms of engraftment in two centers in Uruguay, one with cryopreservation (Hospital Británico-HB) and the other with 4oC storage (Hospital Maciel-HM). Results: 69 patients were included during Oct 15, 2018 and Dec 23, 2023. Median age was 60 years old (32-72). The median of collected PBSC was 9.0 x 106/kg (range 2.7 - 32.3), and the median of PBSC infused was 5.4 x 106/kg, (range 2.7 - 10.8). The time to neutrophil engraftment was 10 days (range 6-12) in HM and 9 days (range 7-12) in HB (p=0.38). The time for platelet engraftment was 20 days (range 17-25) in HM and 19 days (range 15-30) in HB (p=0.14). There were no graft failures, and no treatment-related mortality was observed at 100 days. Conclusions: Both cryopreserved and non-cryopreserved strategies appear to achieve similar outcomes in terms of engraftment and safety. Non-cryopreservation could be a way to improve affordability and accessibility to aHCT in MM, particularly in resource-limited areas.