Fludarabine, cyclophosphamide, anti-thymocyteglobulin, and low-dose total body irradiation conditioning enables 1-HLA-locus-mismatched hematopoietic stem cell transplantation for very severe aplastic anemia without affecting ovarian function

Optimizing conditioning regimen with low-dose irradiation or busulfan enables the outcome of transplantation from a 6-7/8 HLA-matched donor comparable to that from an 8/8 HLA-matched unrelated donor in severe aplastic anemia patients under 40 years

With the dramatic improvements in outcomes following alternative donor hematopoietic stem cell transplantation (HSCT), interest in the use of alternative donors in severe aplastic anemia (SAA) is increasing. We conducted a multicenter prospective study to explore the efficiency and safety of upfront HSCT from a 6-8/8 HLA-matched unrelated donor (MUD) or 6-7/8 HLA-matched related donor (MRD) in acquired SAA patients under 40 years. Between August 2014 and July 2017, 115 patients were enrolled, including 48 (41.7%) patients receiving grafts from an 8/8 MUD, 25 (21.7%) from a 6-7/8 MRD, and 42 (36.5%) from a 6-7/8 MUD. The incidence of grade II-IV acute graft-versus-host disease (GVHD) was higher in the 6-7/8 MUD group than in the 8/8 MUD group (42.9% vs. 12.8%, P=0.001). The corresponding incidence in the 6-7/8 MRD group was comparable to that in the 8/8 MUD group (21.7% vs. 12.8%, P=0.332). There was no significant difference in the incidence of chronic GVHD (24.3%, 13.6%, and 17.9%, P=0.676), graft failure (2.4%, 8.0%, and 6.3%, P=0.551), overall survival (85.7%, 96.0%, and 87.5%, P=0.424), and failure-free survival (83.3%, 88.0%, and 83.3%, P=0.885) among the three groups (6-7/8 MUD, 6-7/8 MRD, and 8/8 MUD). In multivariate analysis, conditioning regimen without low-dose irradiation or busulfan was associated with an inferior failure-free survival (HR=2.973, P=0.042). In conclusion, after an intensified conditioning regimen with additional low-dose irradiation or busulfan, the outcome of HSCT from a 6-7/8 MRD or 6-7/8 MUD is comparable to that from an 8/8 MUD.

Allogeneic hematopoietic stem cell transplantation for aplastic anemia with pre-transplant conditioning using fludarabine, reduced-dose cyclophosphamide, and low-dose thymoglobulin: A KSGCT prospective study

The optimal pre-transplant conditioning for aplastic anemia (AA) remains unclear. We performed a prospective study on allogeneic transplantation from a related or unrelated donor for adult patients with AA. We assessed whether reduced-dose cyclophosphamide (CY) could decrease toxicity while maintaining engraftment, and low-dose thymoglobulin could safely prevent graft-vs-host disease (GVHD). The pre-transplant conditioning regimen consisted of fludarabine 120 mg/m² , CY 100 mg/kg, and thymoglobulin 2.5 mg/kg with or without 2 Gy of total body irradiation. Twenty-seven patients with a median age of 36 years were analyzed. Sixteen patients received graft from related donors. The stem cell source was bone marrow in 26 patients. All of the patients but one, who died early, achieved neutrophil engraftment at a median of 19 days. Mixed chimerism was observed in six and five patients at days 30 and 90, respectively. Only one patient experienced secondary engraftment failure with complete donor-type chimerism. None of the patients developed severe acute GVHD. The cumulative incidence of chronic GVHD was 37.7% at 1 year. The overall survival rate was 96.3% at 1 year and 3 years. A high EB virus-DNA load was detected in one patient at days 60. No one developed EBV-lymphoproliferative disorder within a year. The results suggest that the conditioning regimen in this study was safe and effective. However, relatively high incidence of chronic GVHD needs further improvement.

Alternative donor transplants for severe aplastic anemia

Allogeneic hematopoietic stem-cell transplantation remains the only curative treatment for patients with acquired severe aplastic anemia (SAA). When a matched sibling is not available, one can search for a matched unrelated donor or a cord blood unit (CB) in the international registries or, more recently, for an HLA haploidentical (HAPLO) family member. International guidelines call for a course of antithymocyte globulin (ATG) and cyclosporine before a patient with SAA receives a transplant from a donor other than an HLA identical sibling, but whether this is necessary for patients age <20 years is less clear. Here I will examine the rapid increase in HAPLO transplantations for SAA, showing encouraging early results both in children and young adults. Graft-versus-host disease prophylaxis remains of primary importance in patients with SAA, and in vivo T-cell depletion with either ATG or alemtuzumab offers a significant survival advantage. Finally, I will discuss the strong age effect, which is particularly evident at >40 and 50 years of age for reasons not entirely clear and which should be taken into account when designing a treatment strategy for a given patient.

How I treat acquired aplastic anemia

Acquired severe aplastic anemia (SAA) is a rare hematologic disease associated with significant morbidity and mortality. Immune destruction of hemopoietic stem cells plays an important role in pathogenesis, as shown by successful treatment with immunosuppressive agents, leading to transfusion independence or complete recovery of peripheral blood counts in a proportion of patients. Growth factors can be combined with immunosuppressive therapy (IST) and may improve response rates, as recently shown with thrombopoietin analogs. Anabolic steroids may still play a role in combination with IST. The problem with IST is failure to respond and the development of late clonal disorders. Bone marrow transplantation (BMT) is the other therapeutic option: a matched sibling donor remains the best choice. For patients lacking a matched family donor, unrelated donors can be readily found, although mostly for patients of Caucasian origin. Other BMT options include unrelated cord blood or mismatched family donors. Acute and chronic graft-versus-host disease remain important complications of BMT. Patient age is a strong predictor of outcome for both IST and BMT, and must be considered when designing therapeutic strategies. Early diagnosis and treatment, as well as long-term monitoring, remain crucial steps for successful treatment of SAA.

Alternative donor transplants for severe aplastic anemia: current experience

Patients with acquired severe aplastic anemia (SAA), who lack a human leukocyte antigen (HLA) identical sibling donor (SIB), have two therapeutic options: immunosuppressive therapy with anti-thymocyte globulin (ATG) and cyclosporine (CsA), or a transplant from an alternative donor. In these patients, the current guidelines of the European Group for Blood and Marrow Transplantation (EBMT) call for a course of ATG + CsA first and transplantation in case of no response. The alternative donor source can be an unrelated donor (UD), a cord blood (CB) unit, or a family mismatched member, in most instances genetically HLA haplo-mismatched (HAPLO). In the present review, we will discuss recent results of transplants from matched UD and SIB donors, with significantly improved outcome, especially with UD in the past decade. We will also be looking at CB transplants, and the problems of limited stem cell dose. Finally HAPLO grafts have been explored in patients lacking or having rejected an unrelated or CB graft: early results seem encouraging, though the procedure should still be considered experimental.

Fulminant hepatic failure caused by adenovirus infection mimicking peliosis hepatitis on abdominal computed tomography images after allogeneic hematopoietic stem cell transplantation

Disseminated adenovirus disease after allogeneic hematopoietic stem cell transplantation (HSCT) is lethal in most cases, especially when it develops as fulminant hepatic failure. We encountered a patient who developed fulminant hepatic failure caused by adenovirus infection. She did not show manifestations of graft-versus-host disease and the results of serum tests for viral infection were all negative. Abdominal computed tomography (CT) findings were consistent with peliosis hepatitis. She died of fulminant hepatic failure, however, and pathological examinations of the liver specimen obtained after her death revealed adenovirus infection. In this report, we review the clinical characteristics and imaging findings of fulminant hepatic failure caused by adenovirus infection.

Retrospective evaluation of the area over the neutrophil curve index to predict early infection in hematopoietic stem cell transplantation recipients

We investigated the impact of neutropenia on the development of early bloodstream and pulmonary infections in hematopoietic stem cell transplantation (HSCT) recipients, and evaluated the utility of an index (D-index) that reflects both the intensity and duration of neutropenia. Fifty-eight patients (23 autologous, 35 allogeneic HSCT recipients) were enrolled in this retrospective study. The D-index was defined as the area over the neutrophil curve during neutropenia. We also evaluated the utility of the cumulative D-index from the start of neutropenia until the development of infection (c-D-index), which may enable real-time assessment of the risk for infection. The patients showed 12 and 7 episodes of bloodstream and pulmonary infection, respectively. The D-index, days of neutropenia (<500/microL) and days of profound neutropenia (<100/microL) had at least a nearly significant impact on the development of both bloodstream and pulmonary infections. On the other hand, the c-D-index, cumulative days of neutropenia, and cumulative days of profound neutropenia significantly affected pulmonary infection, but not bloodstream infection. The c-D-index had a high negative predictive value of 97.4% for pulmonary infection with a cutoff of 5500, but the area under the receiver operating characteristic curve was similar to that of the cumulative days of neutropenia and profound neutropenia. Our results showed that although the c-D-index may be useful for identifying patients who are at low risk for early pulmonary infection after HSCT, its performance was similar to that of the simple duration of neutropenia.

The effect of different ATG preparations on immune recovery after allogeneic hematopoietic stem cell transplantation for severe aplastic anemia

Anti-thymocyte globulin (ATG) is widely used in the conditioning regimen before allogeneic stem cell transplantation for aplastic anemia. However, there are several different preparations of ATG and little is known about the difference of their effects on transplantation outcome. Therefore, in this study, we retrospectively compared the effect of two different rabbit ATG preparations [Thymoglobulin (ATG-G) and ATG-Fresenius (ATG-F)] on immune recovery and cytomegalovirus infection after transplantation. The conditioning regimen was a combination of fludarabine, cyclophosphamide, and ATG. Low dose total body irradiation was added in alternative donor transplantation. Four patients received ATG-F at 5 mg/kg/day from day -7 to day -3, whereas ATG-G was given at 2.5 mg/kg/day from day -5 to day -2 in three patients. There was no graft rejection and no grade II-IV acute graft-versus-host disease. All three patients in the ATG-G group developed positive cytomegalovirus antigenemia including two with high-grade antigenemia, whereas two of the four patients in the ATG-F group were persistently negative. Immunological evaluation on day 60 revealed that both CD4+ and CD8+ T-cell recoveries were delayed in the ATG-G group. These findings suggested that ATG-G has a stronger immunosuppressive activity than the ATG-F with a dose ratio of 1:2.5.

Fludarabine, cyclophosphamide, antithymocyte globulin, with or without low dose total body irradiation, for alternative donor transplants, in acquired severe aplastic anemia: a retrospective study from the EBMT-SAA Working Party

BACKGROUND

We analyzed the outcome of 100 patients with acquired severe aplastic anemia undergoing an alternative donor transplant, after immune suppressive therapy had failed.

DESIGN AND METHODS

As a conditioning regimen, patients received either a combination of fludarabine, cyclophosphamide, and antithymocyte globulin (n=52, median age 13 years) or this combination with the addition of low dose (2 Gy) total body irradiation (n=48, median age 27 years).

RESULTS

With a median follow-up of 1665 and 765 days, the actuarial 5-year survival was 73% for the group that received fludarabine, cyclophosphamide, and antithymocyte globulin and 79% for the group given the conditioning regimen including total body irradiation. Acute graft-versus-host disease grade III-IV was seen in 18% and 7% of the groups, respectively. Graft failure was seen in 17 patients with an overall cumulative incidence of 17% in patients receiving conditioning with or without total body irradiation: 9 of these 17 patients survive in the long-term. The most significant predictor of survival was the interval between diagnosis and transplantation, with 5-year survival rates of 87% and 55% for patients grafted within 2 years of diagnosis and more than 2 years after diagnosis, respectively (P=0.0004). Major causes of death were graft failure (n=7), post-transplant-lymphoproliferative-disease (n=4) and graft-versus-host disease (n=4).

CONCLUSIONS

This study confirms positive results of alternative donor transplants in patients with severe aplastic anemia, the best outcomes being achieved in patients grafted within 2 years of diagnosis. Prevention of rejection and Epstein-Barr virus reactivation may further improve these results.