Pair-matched study of cryopreserved versus native graft in adult and pediatric recipients of allogeneic hematopoietic stem cell transplantation

Abstract

Cryopreservation (Cryo) of a graft is a standard procedure in autologous hematopoietic stem cell transplantation (HSCT), however there is a lack of studies on the safety and efficacy of allogeneic HSCT with cryopreserved graft. We have conducted a pair-matched study in 81 patients transplanted with frozen graft and compared them to 81 control patients with fresh cell graft. The groups were matched by age, disease type and stage, conditioning, donor type, graft-versus-host disease (GVHD) prophylaxis and number of CD34-postive cells in the graft. The study group comprised 83% unrelated HSCTs, 72% of peripheral blood stem cell recipients and 40% of salvage patients. No differences were observed between the Cryo and control group in the incidence of grade II-IV acute GVHD (39% vs 37%, p=0.89), moderate and severe chronic GVHD (29% vs 30%, p=0.39), overall survival (37% vs 44%, p=0.24), event-free survival (35% vs 40%, p=0.38) and GVHD-relapse-free survival (19% vs 25%, p=0.20), respectively. However, non-relapse mortality (NRM) was significantly higher in the Cryo group (45% vs 28%, p=0.015), which was compensated by reduced relapse incidence (21% vs 34%, p=0.048). The leading factor for NRM were trends to higher incidence of primary graft failure (15,7% vs 6.3%, p=0.059) and sepsis during aplasia (24% vs 13%, p=0.068). No differences were observed in the time to neutrophil and platelet engraftment. Complications of HSCT were comparable between groups except higher incidence of grade II-IV nephrotoxicity in the Cryo group (30% vs 10%, p=0.0046). In conclusion, the study demonstrated that the results of allogeneic HSCT with cryopreserved graft are comparable to native graft ones. Trends to higher primary graft failure, infectious complications and NRM should be confirmed in the multicenter studies.