Effect of Stem Cell Source and Dose on Allogeneic Hematopoietic Stem Cell Transplantation in Adult Patients with Idiopathic Aplastic Anemia: Data from the Korean Aplastic Anemia Trials

T Cell-Depleted Peripheral Blood versus Unmanipulated Bone Marrow in Matched Sibling Transplantation for Aplastic Anemia

Bone marrow (BM) is the recommended stem cell source for hematopoietic stem cell transplantation (HSCT) from matched sibling donors (MSDs) in patients with severe aplastic anemia (SAA) for its superior survival and graft-versus-host disease (GVHD) outcomes compared to recipients of unmanipulated peripheral blood (PB) HSCT. Nevertheless, no studies comparing BM with ex vivo T cell-depleted (TCD) PB have been reported to date. The aim of the present study was to compare the transplantation outcomes of MSD HSCT recipients with SAA using PB (with partial ex vivo TCD targeted cell dose grafts) with those of MSD HSCT recipients with SAA using unmanipulated BM. We performed a matched-pair analysis of MSD-HSCT using TCD PB in a single institution with unmanipulated BM MSD-HSCT in the United States between 2013 and 2019 reported to the Center for International Blood and Marrow Transplant Research. We compared 23 recipients of TCD PB HSCT for SAA (cases) and 69 recipients of unmanipulated BM grafts (controls) matched for age, Karnofsky Performance Status, Hematopoietic Cell Transplantation-Specific Comorbidity Index, time from diagnosis to transplantation, and recipient cytomegalovirus serostatus. We found significantly faster neutrophil and platelet recovery in the TCD PB cohort (P < .001 and P = .03, respectively), as well as a lower incidence of grade II-IV acute GVHD (0% versus 17%; P = .05) and similar overall survival (96% versus 97% at 3 years; P = .8). Our study shows that TCD PB can be considered a safe source for MSD-HSCT in patients with SAA, with potential advantages in engraftment and GVHD that could challenge the standard with BM. These findings provide a basis for future research in a prospective controlled clinical trial.

Special issues related to the diagnosis and management of acquired aplastic anemia in countries with restricted resources, a report on behalf of the Eastern Mediterranean blood and marrow transplantation (EMBMT) group and severe aplastic anemia working party of the European Society for blood and marrow transplantation (SAAWP of EBMT)

Aplastic anemia is a relatively rare but potentially fatal disorder, with a reported higher incidence in developing countries in comparison to the West. There are significant variations in epidemiological as well as etiological factors of bone marrow failure syndromes in the developing countries in comparison to the developed world. Furthermore, the management of bone marrow failure syndromes in resource constraint settings has significant challenges including delayed diagnosis and referral, limited accessibility to healthcare facilities, treatment modalities as well as limitations related to patients who require allogeneic stem cell transplantation. Here we will provide a review of the available evidence related to specific issues of aplastic anemia in the developing countries and we summarize suggested recommendations from the Eastern Mediterranean blood and bone marrow transplantation (EMBMT) group and the severe aplastic anemia working party of the European Society of blood and marrow transplantation (SAAWP of EBMT) related to the diagnosis and therapeutic options in countries with restricted resources.

Haploidentical Peripheral Stem Cell Transplantation for Young Patients with Severe Aplastic Anemia Using Post-Transplantation Cyclophosphamide and Methotrexate

Severe aplastic anemia (SAA) is a serious bone marrow failure disorder that is often cured with hematopoietic stem cell transplantation (HSCT). The absence of a matched related donor is common, however, and thus novel approaches are needed to safely expand the donor pool to include alternative donors, especially haploidentical related donors, for patients with SAA. This study aimed to explore a novel approach to HSCT for patients with SAA without an available HLA-identical sibling or a matched unrelated donor, termed haploidentical peripheral blood stem cell transplantation (haplo-PBSCT), using a conditioning regimen comprising cyclophosphamide, busulfan, and fludarabine (CBF) and a graft-versus-host disease (GVHD) prophylaxis regimen with post-transplantation cyclophosphamide (PTCy), low-dose methotrexate (LD-MTX), and calcineurin inhibitors. This prospectively designed nonrandomized study included 29 patients with SAA who underwent haplo-PBSCT between November 2017 and May 2020. The median patient age was 17 years (range, 14 to 30 years), and the median time to neutrophil recovery was 13 days (range, 13 to 15 days). There was 1 primary graft failure (GF) in the group receiving PTCy at a dose of 50 mg/kg and no GFs in the group receiving PTCy at a dose of 100 mg/kg. The median duration of follow-up was 736 days (95% confidence interval, 512 to 879 days). The estimated 1-year overall survival and disease-free survival were 91.7 ± 5.7% and 89.7 ± 5.7%, respectively. Only 1 of the 27 patients developed grade II acute GVHD. Four patients developed limited and mild chronic GVHD, involving only the skin or/and oral mucosa. Haplo-PBSCT following CBF and followed by PTCy and LD-MTX represents a novel approach for safely expanding the donor pool to include alternative donors for young patients with SAA.