Impact of Iron Overload and Iron Chelation with Deferasirox on Outcomes of Patients with Severe Aplastic Anemia after Allogeneic Hematopoietic Stem Cell Transplantation

Abstract

Patients suffering from severe aplastic anemia (SAA) need frequent blood transfusions during allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, these transfusions can result in an excess of iron in the body tissues, which can negatively impact the success of transplantation. This study aimed to examine the impact of pretransplantation iron overload (IO) on the outcomes of allo-HSCT in patients with SAA. It also investigated whether iron chelation (IC) therapy is necessary to enhance transplantation outcomes in SAA patients by providing guidelines for determining when excess iron should be chelated. The study consisted of 2 parts. In cohort 1, which was retrospective and conducted from April 2012 to December 2018, SAA patients receiving their first allo-HSCT were divided into 2 groups based on their pretransplantation serum ferritin (SF) level: the IO group (SF >1000 ng/mL; n = 17) and the non-IO group (SF ≤1000 ng/mL; n = 48). Cohort 2, a prospective clinical trial conducted from January 2019 to July 2020, included SAA patients diagnosed with IO who were treated with IC therapy using deferasirox at a dose of 10 to 30 mg/kg. Patients were separated into 2 groups based on their pretransplantation SF level: the IC success (IC^success) group (SF ≤1000 ng/mL; n = 18) and the IC failure (IC^failure) group (SF >1000 ng/mL; n = 28). All participants were evaluated for the correlation between pretransplantation SF level and transplantation outcomes. A P value <.05 was considered statistically significant. There was no significant difference in the speed of engraftment among the 3 cell lineages or in the incidence of 100-day grade II-IV acute graft-versus-host disease (aGVHD), grade III-IV aGVHD, or 3-year chronic GVHD between the 2 groups in both cohorts. Of note, however, in cohort 1, both 1-year overall survival (OS) (41.2% versus 83.3%; P < .001) and 3-year OS (35.3% versus 83.3%; P < .001) were significantly worse in the IO group. Furthermore, 180-day transplantation related mortality (TRM) (47.1% versus 14.6%; P = .005) and 1-year TRM (52.9% versus 16.7%; P = .002) were significantly higher in the IO group. The IO group was significantly associated with inferior 3-year OS in both univariate and multivariate analyses. In cohort 2, 1-year OS (88.9% versus 42.9%; P = .003) and 3-year OS (83.3% versus 42.9%; P = .007) were significantly better in the IC^success group, whereas 180-day TRM (11.1% versus 39.3%; P = .040) and 1-year TRM (11.1% versus 57.1%; P = .003) were significantly lower in the IC^success group. These differences were confirmed in both univariate and multivariate analyses. This study involving 2 cohorts shows that pre-HSCT IO has a negative impact on transplantation outcomes in SAA patients. Chelating excess iron with an SF level <1000 ng/mL was found to be necessary and could potentially improve the outcomes.

Keywords: Allogeneic hematopoietic stem cell transplantation; Deferasirox; Iron chelation; Iron overload; Severe aplastic anemia.