Treatment of aplastic anemia with antilymphocyte globulin and methylprednisolone with or without cyclosporine. The German Aplastic Anemia Study Group

Modified Delphi panel consensus recommendations for management of severe aplastic anemia

ABSTRACT

Severe aplastic anemia (SAA) is a rare hematologic condition for which there is no clear management algorithm. A panel of 11 experts on adult and pediatric aplastic anemia was assembled and, using the RAND/University of California, Los Angeles modified Delphi panel method, evaluated >600 varying patient care scenarios to develop clinical recommendations for the initial and subsequent management of patients of all ages with SAA. Here, we present the panel's recommendations to rule out inherited bone marrow failure syndromes, on supportive care before and during first-line therapy, and on first-line (initial management) and second-line (subsequent management) therapy of acquired SAA, focusing on when transplant vs medical therapy is most appropriate. These recommendations represent the consensus of 11 experts informed by published literature and experience. They are intended only as general guidance for experienced clinicians who treat patients with SAA and are in no way intended to supersede individual physician and patient decision making. Current and future research should validate this consensus using clinical data. Once validated, we hope these expert panel recommendations will improve outcomes for patients with SAA.

Treatment of newly diagnosed severe aplastic anemia in children: Evidence-based recommendations

Severe aplastic anemia (SAA) is a rare potentially fatal hematologic disorder. Although overall outcomes with treatment are excellent, there are variations in management approach, including differences in treatment between adult and pediatric patients. Certain aspects of treatment are under active investigation in clinical trials. Because of the rarity of the disease, some pediatric hematologists may have relatively limited experience with the complex management of SAA. The following recommendations reflect an up-to-date evidence-based approach to the treatment of children with newly diagnosed SAA.

A patient with axial spondylarthritis who experienced pancytopenia while receiving anti-TNF therapy

Aplastic anemia is a rare and heterogeneous disease that causes pancytopenia and aplasia of the bone marrow. It is characterized by a failure of hematopoiesis. It is believed that approximately 65% of cases of acquired aplastic anemia are idiopathic. In a subset of cases, a drug or infection is the cause of bone marrow failure. This case report presents a 38-year-old patient with axial spondylarthritis who developed pancytopenia and was diagnosed with aplastic anemia during anti-TNF-α treatment.

Mendelian randomization of circulating proteome identifies IFN-γ as a druggable target in aplastic anemia

BACKGROUND

Aplastic anemia (AA) is a kind of bone marrow failure (BMF) characterized by pancytopenia with hypoplasia/aplasia of bone marrow. Immunosuppressive therapy and bone marrow transplantation are effective methods to treat severe aplastic anemia. However, the efficacy is limited by complications and the availability of suitable donors. This study aimed to determine whether any circulating druggable protein levels may have causal effects on AA and provide potential novel drug targets for AA.

METHODS

Genetic variants strongly associated with circulating druggable protein levels to perform Mendelian randomization (MR) analyses were used. The effect of these druggable protein levels on AA risk was measured using the summary statistics from a large-scale proteomic genome-wide association study (GWAS) and FinnGen database ( https://www.finngen.fi/en/access_results ). Multivariable MR analyses were performed to statistically adjust for potential confounders, including platelet counts, reticulocyte counts, neutrophil counts, and proportions of hematopoietic stem cells.

RESULTS

The data showed that higher level of circulating IFN-γ levels was causally associated with AA susceptibility. The causal effects of circulating IFN-γ levels on the AA were broadly consistent, when adjusted for platelet counts, reticulocyte counts, neutrophil counts and proportions of hematopoietic stem cells.

CONCLUSIONS

High levels of circulating IFN-γ levels might increase the risk of AA and might provide a potential novel target for AA.

Progress in medical therapy in aplastic anemia: why it took so long?

The treatment of aplastic anemia (AA) has significantly advanced in the last 50 years, evolving from a fatal condition to one where survival rates now exceed 80-85%. Hematopoietic stem cell transplantation (HSCT) and immunosuppressive therapy (IST) have become the primary treatments, with the latter widely adopted due to factors like the scarcity of compatible donors, patient age, comorbidities, and limited HSCT access. A therapy breakthrough was the introduction of antithymocyte globulin (ATG), with its effectiveness further boosted by cyclosporine. However, it took years to achieve another major milestone in management. Initially, treatments aimed to intensify immunosuppression following the success of the ATG-cyclosporine combination, but these methods fell short of expectations. A major turning point was combining immunosuppression with stem cell stimulation, surpassing the efficacy of IST alone. Earlier, growth factors had shown limited success in AA treatment, but thrombopoietin receptor agonists represented a significant advancement. Initially applied alone as salvage, these were later combined with IST, forming the most effective current regimen for medically managing SAA. Horse ATG is the preferred formulation combined with cyclosporine and eltrombopag. This progress in AA treatment offers improved outcomes for patients afflicted with this once-lethal disease.

Aplastic anemia: history and recent developments in diagnosis and treatment

Acquired aplastic anemia is an immune-mediated disease that targets hematopoietic stem cells, which is diagnosed by findings of peripheral blood pancytopenia and hypocellular bone marrow. Although the diagnostic definition is simple, differential diagnosis from other overlapping hematopoietic disorders such as hypoplastic myelodysplastic syndrome and inherited bone marrow failure syndrome is not easy. Immune suppressive therapy and allogeneic hematopoietic stem cell transplantation are important treatment approaches for aplastic anemia, and both have advanced in recent years. This issue of Progress in Hematology covers four topics related to aplastic anemia: (1) laboratory markers to identify immune pathophysiology and their role on differential diagnosis and prognosis, (2) the path to combination therapy with horse anti-thymocyte globulin, cyclosporine A, and eltrombopag, (3) more than 60 years of history and recent trends in allogeneic HSCT, and (4) genetic testing for differential diagnosis from IBMFS and novel approaches to transplantation for children including fludarabine/melphalan-based conditioning.

Avatrombopag, a promising novel thrombopoietin receptor agonist for refractory/relapsed/intolerant non-severe aplastic anemia: a phase 2 single-arm clinical trial

INTRODUCTION

The therapeutic options for thrombocytopenia in non-severe aplastic anaemia (NSAA) are limited. Avatrombopag (AVA) is prescribed for thrombocytopenic diseases but not for NSAA.

METHODS

Herein, we conducted a phase 2, non-randomized, single-arm trial to explore the efficacy and safety of AVA in refractory/relapsed/intolerant NSAA. AVA dose was initiated at 20 mg/d and titrated to a maximum of 60 mg/d. The primary endpoint was the haematological response at 3 months.

RESULTS

Twenty-five patients were analyzed. The overall response rate (ORR) at 3 months was 56% (14/25), with 12% (3/25) achieving a complete response (CR). At a median follow-up of 7 (3-10) months, the OR and CR rates were 52% and 20%, respectively. Responders had a shorter duration of diagnosis of AVA administration than non-responders (10 (6-80) vs 37 (6-480) months, p = 0.027) and belonged to the relapsed/intolerant NSAA type (71% vs 27%, p = 0.047); 44% (8/18) patients previously treated with eltrombopag before enrollment responded at 3 months, with an average prior eltrombopag dose of median 72.5 (50-100) mg/d and an average AVA dose for a response of median 43.5 (20-60) mg/d. 3-month ORR had no significant correlation with eltrombopag exposure (p = 0.09), prior eltrombopag length (R²=0.11), or cumulative eltrombopag dose (R²=0.30). Only one patient relapsed after stopping AVA for 1 month. No serious AVA-related side effects or clone evolution were detected.

CONCLUSION

AVA is effective and well-tolerated in NSAA patients who are refractory, relapsed, or intolerant to CsA/tacrolimus ± eltrombopag. Earlier treatment and relapsed/intolerant AA may show a better short-term response rate. More studies are needed to define the optimal dose and the long-term efficacy (NCT04728789).

Repeated immunosuppressive rabbit antithymocyte globulin therapy for adult patients with relapsed or refractory aplastic anemia

OBJECTIVES

Immunosuppressive therapy (IST) with antithymocyte globulin (ATG) and cyclosporin A is the standard treatment for aplastic anemia (AA). However, the efficacy of repeated IST with rabbit ATG (rATG) as salvage therapy remains unclear in patients with relapsed or refractory AA.

METHODS

We retrospectively evaluated the efficacy and safety of IST2 with rATG (IST2-rATG) in 19 consecutive patients with relapsed or refractory AA who received first-line IST with rATG in two centers between 2009 and 2020.

RESULTS

The overall 6-month response rate of the patients was 58%. The response rates were similar between patients with relapsed and refractory AA. The presence of glycophosphatidylinositol-deficient blood cells was associated with a better response to IST2-rATG. Despite retreatment with the same rATG, serum disease and severe allergic reactions were not observed.

CONCLUSION

IST2-rATG is effective and safe for the treatment of adult patients with relapsed and refractory AA after receiving first-line IST with rATG.

Indigenous antithymocyte globulin-equine to treat aplastic anaemia in adults: a case series from two centres in northeast India

BACKGROUND

Immunosuppressive therapy is the standard management of adults with aplastic anaemia. Antithymocyte globulin is used as first-line treatment of patients not eligible for bone marrow transplantation. This being a rare disease, available evidence in India is scarce. This study aimed to present experience in treating adult aplastic anaemia patients by immunosuppressive therapy using antithymocyte globulin-equine (Thymogam) in two tertiary care centres of northeast India.

METHODS

This case series was conducted at the Health city hospital, Guwahati, and Excel Care Hospital, Guwahati from 2018 to 2020. Eighteen adult aplastic anaemia patients who were treated by immunosuppressive therapy with antithymocyte globulin-equine (Thymogam) and followed up for two years were included. Treatment response and relapse are described.

RESULTS

All the 18 patients, (14 severe, four very severe) were uniformly treated with immunosuppressive therapy (Thymogam 40 mg/kg/d for four days with oral Cyclosporine from Day-1). Cyclosporin A was used as a concomitant drug in 94.44 % of the patients. At two years of follow up, 66.7 % showed a response and the mortality rate was 11.1 %.

CONCLUSION

The results of this case series substantiate the effectiveness of immunosuppressive therapy with a low-cost preparation of horse antithymocyte globulin (Thymogam) along with cyclosporin A in the management of aplastic anaemia patients not suitable for bone marrow transplantation.

Aplastic anemia from past to the present: A bibliometric analysis with research trends and global productivity during 1980 to 2022

There is no bibliometric study in the literature on Aplastic Anemia (AA). In the present study, the purpose was to summarize the intellectual structure of the subject, uncover the global productivity in this respect, and identify the latest research trends by performing a bibliometric analysis of the articles published on AA. For this purpose, outputs for different research components of scientific outputs (i.e., countries, institutions, journals, and authors) were analyzed. A total of 3221 articles on Aplastic Anemia published between 1980 and 2022 were analyzed by using various statistical methods and bibliometric approaches. The Spearman Correlation Coefficient was used for correlation analysis and bibliometric network visualization maps were used to identify trending topics, citation analysis, and international collaborations. The top 3 contributing countries to the literature were the USA in this respect (800, 24.8%), China (514, 15.9%), and Japan (442, 13.7%). The top 3 most active institutions were the National Institutes of Health USA (n = 177), National Heart Lung Blood Institute (n = 153), and Udice French Research Universities (n = 136). The top 3 most productive journals were the British Journal of Haematology (n = 239), Blood (n = 181), and Bone Marrow Transplantation (n = 137). The most prolific author was Neal Stuart Young (n = 130). Specific keywords that were most frequently used in articles were severe aplastic anemia, immunosuppressive therapy, pediatrics/children, anti-thymocyte globulin, cyclosporine, hematopoietic stem cell transplantation, myelodysplastic syndromes, Paroxysmal Nocturnal Hemoglobinuria, hepatitis-associated aplastic anemia, allogeneic stem cell transplantation, haploidentical hematopoietic stem cell transplantation, pancytopenia, eltrombopag, fludarabine, Graft-Versus-Host Disease, survival, apoptosis, cytokines, and cyclophosphamide. It was determined that the trend topics in recent years were eltrombopag, COVID-19, Treg, Th17, thrombopoietin receptor agonists, haploidentical hematopoietic stem cell transplantation, haploidentical donor/transplantation, and posttransplantation cyclophosphamide. In the formation of the AA literature, it was determined that the research leadership belonged to the USA, China, Japan, European countries (United Kingdom, Italy, Germany, France, Switzerland), India, and South Korea, which have large economies.

Profile and Predictors of Infection Following Anti-thymocyte Globulin or Anti-lymphocyte Globulin with Cyclosporine in Aplastic Anemia

Immunosuppressive therapy (IST) with anti-thymocyte globulin (ATG) and Cyclosporine (CSA) in aplastic anaemia (AA) results in improvement of blood counts between 3 and 6 months for the majority of patients. Infection is the most lethal complication in aplastic anemia and may arise due to several factors. We performed this study to determine the prevalence and predictors of specific infection types before and after IST. Six hundred and seventy-seven (546 adults; 434 males) transplant ineligible patients received ATG and CSA between 1995 and 2017. All patients who were transplant ineligible and received IST in this period were included. Infections before IST was seen in 209 (30.9%) and in 430 (63.5%) patients post IST. There were 700 infective episodes in the six months post-IST, including 216 bacterial, 78 fungal, 33 viral, and 373 culture-negative febrile episodes. Infections were highest (98, 77.8%) in very severe aplastic anaemia as compared to Severe AA (SAA) and Non-Severe AA (NSAA) (p < 0.001). Infections were also significantly higher in those who did not respond to ATG (71.1% vs. 56.8%, p = 0.003). At six months post-IST were 545 (80.5%) alive, and there were 54 (7.9%) deaths due to infection. Significant predictors of mortality were paediatric AA, very severe aplastic anaemia, pre or post ATG infections, and lack of response to ATG. Mortality was highest in those with combined bacterial and fungal infections post IST (p < 0.001). We conclude that infections are a common complication (63.5%) of IST. Mortality was highest when both bacterial and fungal infections were present. Routine use of growth factors and prophylactic antifungal and antibacterial agents was not part of our protocol, despite which 80.5% of the cohort was alive at the end of six months.

Antihuman T lymphocyte porcine immunoglobulin combined with cyclosporine as first-line immunosuppressive therapy for severe aplastic anemia in China: a large single-center, 10-year retrospective study

Background

Antihuman T lymphocyte porcine immunoglobulin (p-ATG) has been the most common ATG preparation in immunosuppressive therapy (IST) in Chinese patients with severe aplastic anemia (SAA) since 2009.

Objectives

This study aimed to evaluate the early hematologic response and long-term outcomes of a large cohort of patients with SAA who received p-ATG plus cyclosporine (CsA) as first-line therapy from 2010 to 2019.

Design

This is a single-center retrospective study of medical records.

Methods

We analyzed the data of 1023 consecutive patients with acquired aplastic anemia (AA) who underwent p-ATG combined with CsA as a first-line IST treatment from 2010 to 2019 at our department.

Results

The median age of the patients was 24 (4-75) years, and the median follow-up time was 57.2 months (3 days-137.5 months). There was an early mortality rate of 2.8% with a median death time of 0.9 months (3 days-2.9 months). The overall response rates were 40.6% and 56.1% at 3 and 6 months, respectively. The 5-year cumulative incidences of relapse and clonal evolution were 9.0% [95% confidence interval (CI) = 4.2-16.0%] and 4.5% (95% CI = 1.4-10.6%), respectively. The 5-year overall survival (OS) and event-free survival rates were 83.7% (95% CI = 81.1-86.0%) and 50.4% (95% CI = 47.1-53.5%), respectively.

Conclusion

p-ATG combined with CsA for the treatment of AA is effective and safe, and p-ATG can be used as an alternative ATG preparation for the standard IST regimen in areas in which h-ATG is not available.

Efficacy and safety of equine anti-thymocyte immunoglobulin (eATG) in three Japanese patients with moderate to very severe aplastic anemia: a case series

Aplastic anemia results from lymphocyte-mediated destruction of hematopoietic stem cells. Immunosuppressive therapy with anti-thymocyte globulin (ATG) and cyclosporine is the standard front-line treatment for patients with severe aplastic anemia who are not suitable candidates for stem cell transplants. PF-06462700 is a potent equine ATG that targets T-lymphocytes and has been approved as a treatment for aplastic anemia outside of Japan for over 30 years. Due to the high medical need for PF-06462700, the Ministry of Health, Labor and Welfare requested its development for Japanese patients with aplastic anemia. In this case series, the efficacy and safety of PF-06462700, administered intravenously at 40 mg/kg/day for 4 days, were assessed over a 24-week period. This was as an open-label, single-arm, multicenter clinical study designed to enroll a minimum of three Japanese participants with aplastic anemia. Two participants met the primary outcome of hematologic response at week 12 and improvements in disease severity were observed. No deaths or serious adverse events were reported. The efficacy results from this case series suggest that administration of PF-06462700 is generally well-tolerated and produces a hematologic response in Japanese patients with aplastic anemia, which should be further evaluated in real-world studies.ClinicalTrials.gov identifier: NCT04350606.

Population Pharmacokinetics of Cyclosporine in Chinese Pediatric Patients With Acquired Aplastic Anemia

Cyclosporine (CsA) is a component of the first-line treatment for acquired aplastic anemia (acquired AA) in pediatric patients. This study aimed to develop a population pharmacokinetic (PK) model of CsA in Chinese pediatric patients with acquired AA to inform individual dosage regimens. A total of 681 CsA whole blood concentrations and laboratory data of 157 pediatric patients with acquired AA were retrospectively collected from two hospitals in Shanghai. A nonlinear mixed-effect model approach was used to build the population PK model. Potential covariate effects of age, body weight, and biochemical measurements (renal and liver functions) on CsA PK disposition were evaluated. Model fit was assessed using the basic goodness of fit and a visual predictive check. The CsA concentration data were accurately described using a two-compartment disposition model with first-order absorption and elimination. Body weight value was implemented as a fixed allometric function on all clearance and volume of distribution parameters. Total bilirubin level was identified as a significant covariate on apparent clearance (CL/F), with a 1.07% reduction per 1 nmol/L rise in total bilirubin level. The final estimates for CL/F and central volume (Vc/F) were 29.1 L/h and 325 L, respectively, for a typical 28 kg child. Other covariates (e.g., gender, age, albumin, hemoglobin, hematocrit, serum creatinine, and concomitant medication) did not significantly affect the PK properties of CsA. This population PK model, along with a maximum a posteriori Bayesian approach, could estimate individual PK parameters in pediatric patients with acquired AA to conduct individual CsA therapy.

Eltrombopag Added to Immunosuppression in Severe Aplastic Anemia

BACKGROUND

A single-group, phase 1-2 study indicated that eltrombopag improved the efficacy of standard immunosuppressive therapy that entailed horse antithymocyte globulin (ATG) plus cyclosporine in patients with severe aplastic anemia.

METHODS

In this prospective, investigator-led, open-label, multicenter, randomized, phase 3 trial, we compared the efficacy and safety of horse ATG plus cyclosporine with or without eltrombopag as front-line therapy in previously untreated patients with severe aplastic anemia. The primary end point was a hematologic complete response at 3 months.

RESULTS

Patients were assigned to receive immunosuppressive therapy (Group A, 101 patients) or immunosuppressive therapy plus eltrombopag (Group B, 96 patients). The percentage of patients who had a complete response at 3 months was 10% in Group A and 22% in Group B (odds ratio, 3.2; 95% confidence interval [CI], 1.3 to 7.8; P = 0.01). At 6 months, the overall response rate (the percentage of patients who had a complete or partial response) was 41% in Group A and 68% in Group B. The median times to the first response were 8.8 months (Group A) and 3.0 months (Group B). The incidence of severe adverse events was similar in the two groups. With a median follow-up of 24 months, a karyotypic abnormality that was classified as myelodysplastic syndrome developed in 1 patient (Group A) and 2 patients (Group B); event-free survival was 34% and 46%, respectively. Somatic mutations were detected in 29% (Group A) and 31% (Group Β) of the patients at baseline; these percentages increased to 66% and 55%, respectively, at 6 months, without affecting the hematologic response and 2-year outcome.

CONCLUSIONS

The addition of eltrombopag to standard immunosuppressive therapy improved the rate, rapidity, and strength of hematologic response among previously untreated patients with severe aplastic anemia, without additional toxic effects. (Funded by Novartis and others; RACE ClinicalTrials.gov number, NCT02099747; EudraCT number, 2014-000363-40.).

Treatment outcome of 301 aplastic anemia patients in China: a 10-year follow-up and real-world data from single institute experience

OBJECTIVE

This study was carried out to explore clinical treatment and prognosis of patients with AA with different economic status. Methods: We retrospectively analyzed the clinical outcome of 301 patients with AA in our center from April 2008 to November 2017.

RESULTS

Treatments included anti-thymocyte globulin (ATG) or anti-lymphocyte globulin (ALG) combined with cyclosporineA (CsA) (9%), allogeneic hematopoietic stem cell transplantation (allo-HSCT) (7%), CsA combined with androgen or CsA alone (hereinafter referred to as CsA group) (77%), no specific therapy (7%). The 5-year overall survival (OS) was higher in patients with non-severe AA (94.6%) compared with those with severe AA (SAA) (66.6%, P <.001), very severe AA (VSAA) (41.3%, P <.001). The 5-year OS was 76.5% in patients with SAA/VSAA treated with ATG/ALG combined with CsA, 75% in allo-HSCT group(P =.936), 63.6% in CsA group (P =.557), which was significantly higher than no specific therapy group (21.8%, P =.002). For those who responded to CsA , the duration of CsA (median follow-up time: 27 months, 1-101 months) was positively correlated with progression-free survival (r=0.603, P <.001). Multivariate analysis revealed that 36-65 years of age, SAA/VSAA, and no specific therapy were independent risk factors for inferior survival.

CONCLUSION

The treatment of elderly patients with AA still faces challenges. CsA is benefit to the survival of SAA/VSAA patients. AA patients, who responded to initialy CsA treatment, may benefit from prolonged CsA treatment. In view of the side effects of CsA, the timing of withdrawal is worth further exploration.

Design, synthesis, and pharmacological evaluation of sinomenine derivatives on rings A and C: Novel compounds screening for aplastic anemia targeting on cytotoxic T lymphocyte

Cytotoxic T lymphocyte (CTL), a key effector cell in aplastic anemia (AA) immune injury, is shown to be a potential target for AA drug therapy. However, there is no candidate for this target till now. Oriented by the inhibition activity of CTL and macrophage derived nitric oxide (NO), a series of novel sinomenine derivatives on rings A and C are designed, synthesized and screened. Among them, compound 3a demonstrates the best inhibitory activity on CTL with an IC₅₀ value of 2.3 μM, and a 97.1% inhibiton rate on macrophage NO production without significant cytotoxicity. Further, compound 3a exhibits substantial therapeutic efficacy on immune-mediated BM failure in AA model mice by improving the symptoms of anemia and the function of BM hematopoiesis, and shows more advantages in life quality improving than cyclosporine A (CsA). Its efficacy on AA at least partly comes from targeting on activated cluster of differentiation (CD)8⁺ T cell. Additionally, 3a also shows much less toxicity (LD₅₀ > 10.0 g/kg) than sinomenine (LD₅₀ = 1.1 g/kg) in preliminary acute toxicity assessment in mice, and has a low risk to inhibit hERG to cause cardiotoxicity. These results indicate that compound 3a merits further investigation for AA treatment by targeting on CTL.

Thrombopoietin receptor agonists for marrow failure: A concise clinical review

Bone marrow failure is characterized by a disruption of hematopoietic stem cell (HSC) homeostasis and function, which causes decreased blood counts. Germline and somatic mutations within HSCs and immune dysregulation contribute to the pathogenesis of marrow failure. Allogeneic HSC transplant is a potentially curative therapy for marrow failure, although not all patients are candidates for this procedure. Immune suppressive therapy (IST) is an effective treatment for patients with aplastic anemia (AA) and select patients with myelodysplastic syndromes, but some patients fail to respond or relapse after IST. Over the past decade, the oral thrombopoietin receptor agonist eltrombopag has become a therapeutic option for AA in combination with frontline IST, and as a single agent for relapsed and refractory patients after IST. In this review, we highlight current knowledge of thrombopoietin receptor agonist mechanisms of action, and clinical indications and toxicities in patients with marrow failure, including the risk of clonal evolution.

Single-cell transcriptomics dissects hematopoietic cell destruction and T-cell engagement in aplastic anemia

Aplastic anemia (AA) is a T cell-mediated autoimmune disorder of the hematopoietic system manifested by severe depletion of the hematopoietic stem and progenitor cells (HSPCs). Nonetheless, our understanding of the complex relationship between HSPCs and T cells is still obscure, mainly limited by techniques and the sparsity of HSPCs in the context of bone marrow failure. Here we performed single-cell transcriptome analysis of residual HSPCs and T cells to identify the molecular players from patients with AA. We observed that residual HSPCs in AA exhibited lineage-specific alterations in gene expression and transcriptional regulatory networks, indicating a selective disruption of distinct lineage-committed progenitor pools. In particular, HSPCs displayed frequently altered alternative splicing events and skewed patterns of polyadenylation in transcripts related to DNA damage and repair, suggesting a likely role in AA progression to myelodysplastic syndromes. We further identified cell type-specific ligand-receptor interactions as potential mediators for ongoing HSPCs destruction by T cells. By tracking patients after immunosuppressive therapy (IST), we showed that hematopoiesis remission was incomplete accompanied by IST insensitive interactions between HSPCs and T cells as well as sustained abnormal transcription state. These data collectively constitute the transcriptomic landscape of disrupted hematopoiesis in AA at single-cell resolution, providing new insights into the molecular interactions of engaged T cells with residual HSPCs and render novel therapeutic opportunities for AA.

Outcomes of haploidentical bone marrow transplantation in patients with severe aplastic anemia-II that progressed from non-severe acquired aplastic anemia

Severe aplastic anemia II (SAA-II) progresses from non-severe aplastic anemia (NSAA). The unavailability of efficacious treatment has prompted the need for haploidentical bone marrow transplantation (haplo-BMT) in patients lacking a human leukocyte antigen (HLA)-matched donor. This study aimed to investigate the efficacy of haplo-BMT for patients with SAA-II. Twenty-two patients were included and followed up, and FLU/BU/CY/ATG was used as conditioning regimen. Among these patients, 21 were successfully engrafted, 19 of whom survived after haplo-BMT. Four patients experienced grade II-IV aGvHD, including two with grade III-IV aGvHD. Six patients experienced chronic GvHD, among whom four were mild and two were moderate. Twelve patients experienced infections during BMT. One was diagnosed with post-transplant lymphoproliferative disorder and one with probable EBV disease, and both recovered after rituximab infusion. Haplo-BMT achieved 3-year overall survival and disease-free survival rate of 86.4% ± 0.73% after a median follow-up of 42 months, indicating its effectiveness as a salvage therapy. These promising outcomes may support haplo-BMT as an alternative treatment strategy for patients with SAA-II lacking HLA-matched donors.

Acquired severe aplastic anaemia: how medical therapy evolved in the 20th and 21st centuries

The progress in aplastic anaemia (AA) management is one of success. Once an obscure entity resulting in death in most affected can now be successfully treated with either haematopoietic stem cell transplantation (HSCT) or immunosuppressive therapy (IST). The mechanisms that underly the diminution of haematopoietic stem cells (HSCs) are now better elucidated, and include genetics and immunological alterations. Advances in supportive care with better antimicrobials, safer blood products and iron chelation have greatly impacted AA outcomes. Working somewhat 'mysteriously', anti-thymocyte globulin (ATG) forms the base for both HSCT and IST protocols. Efforts to augment immunosuppression potency have not, unfortunately, led to better outcomes. Stimulating HSCs, an often-sought approach, has not been effective historically. The thrombopoietin receptor agonists (Tpo-RA) have been effective in stimulating early HSCs in AA despite the high endogenous Tpo levels. Dosing, timing and best combinations with Tpo-RAs are being defined to improve HSCs expansion in AA with minimal added toxicity. The more comprehensive access and advances in HSCT and IST protocols are likely to benefit AA patients worldwide. The focus of this review will be on the medical treatment advances in AA.

The Effectiveness of Rapamycin Combined with Eltrombopag in Murine Models of Immune-Mediated Bone Marrow Failure

Severe aplastic anemia (SAA) is a rare disease characterized by severe pancytopenia and bone marrow failure. Most patients with AA respond to immunosuppressive therapy (IST), usually as antithymocyte globulin (ATG) and cyclosporine (CsA), but some relapse on CsA withdrawal or require long-term administration of CsA to maintain blood counts. Recent research has found that rapamycin (Rapa) was an effective therapy in mouse models of immune-mediated bone marrow failure. However, it has not achieved a satisfactory effect in clinical application. At present, many studies have confirmed that eltrombopag (ELT) combined with IST can improve the curative effect of AA patients. Then, whether Rapa combined Elt in the treatment of AA will acquire better efficacy than a single drug application remains unclear. In this study, an immune attack-mediated AA mouse model was constructed by total body irradiation (TBI) and allo-lymphocyte infusion. In our study, we tested the efficacy of Rapa combined with Elt as a new treatment in mouse models of immune-mediated bone marrow failure. It showed that treatment with Rapa in combination Elt in the AA mouse model ameliorated pancytopenia and extended animal survival in a manner comparable to the standard dose of CsA and Rapa alone. However, there was no significant improvement effect on the number and function of NK cells and their subsets, mDCs, and CD4+/CD8+ ratio in AA mice after the therapy of Rapa combined with Elt compared with Rapa alone. Furthermore, the secretion of IL-10 of Tregs in AA mice increased significantly after the therapy of Rapa combined with Elt, but there was no significant difference in the number of Treg cells. We did not observe the difference in the curative effect of the Rapa group and CsA group, but for IL-10/Tregs ratio, the Rapa group was superior to the CsA group. And the IFN-r secretion of CD8+T cells in AA mice decreased significantly after the combination therapy of Rapa and Elt than Rapa alone. Compared with the AA group, the level of plasma IFN-γ, IL-2, and TNF-α decreased significantly (P < 0.05), but IL-10, IL-4, IL-5, and IL-1β increased significantly in the Rapa group (P < 0.05). As for IL-10, IL-12p70, IL-2, IL-6, KC/GRO, and TNF-α, the therapy of Rapa combined with Elt showed a more significant effect than Rapa alone in AA mice. To some extent, this study had shown a relatively better synergistic effect in murine models of immune-mediated bone marrow failure after the combination therapy of Rapa and Elt, which was a promising clinical utility in SAA treatment.

PNH Clones for Aplastic Anemia with Immunosuppressive Therapy: A Systematic Review and Meta-Analysis

OBJECTIVES

PNH clones, also aptly called "escape clones," are evidence of acquired immune-mediated bone marrow failure and have a high prevalence in patients with aplastic anemia (AA). Several studies have reported contradictory results regarding the impact of PNH clones on AA patients with immunosuppression treatment, and PNH clones have not been confirmed as positive predictors of response in the AA guidelines of the British Society for Standards in Haematology.

METHODS

We performed a meta-analysis to address this issue by searching for articles in PubMed, EMBASE, The Coch-rane Library, Web of Science, and ClinicalTrials.gov, and for abstracts from the annual meetings of the American Society of Hematology and the European Hematology Association. We included 1,236 participants from 11 cohort-controlled studies. Our primary outcome was the 6-month hematologic response with a secondary outcome of the mortality rate within 3 months.

RESULTS

A better response rate was observed in the PNH+ group than in the PNH- group (odds ratio [OR] 2.85; 95% confidence interval [CI] 2.17-3.75; p < 0.00001), and further subgroup analysis strengthened the outcome, with minor heterogeneity in non-Asian countries. In contrast, the early mortality was not significantly different between the PNH+ and PNH- groups (OR 0.54; 95% CI 0.26-1.10; p = 0.09).

CONCLUSIONS

The meta-analysis suggested an evidence-based role for PNH clones in predicting a better response in AA patients with immunosuppression.

Secondary myelodysplastic syndrome and leukemia in acquired aplastic anemia and paroxysmal nocturnal hemoglobinuria

Acquired aplastic anemia (AA) and paroxysmal nocturnal hemoglobinuria (PNH) are pathogenically related nonmalignant bone marrow failure disorders linked to T-cell-mediated autoimmunity; they are associated with an increased risk of secondary myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). Approximately 15% to 20% of AA patients and 2% to 6% of PNH patients go on to develop secondary MDS/AML by 10 years of follow-up. Factors determining an individual patient's risk of malignant transformation remain poorly defined. Recent studies identified nearly ubiquitous clonal hematopoiesis (CH) in AA patients. Similarly, CH with additional, non-PIGA, somatic alterations occurs in the majority of patients with PNH. Factors associated with progression to secondary MDS/AML include longer duration of disease, increased telomere attrition, presence of adverse prognostic mutations, and multiple mutations, particularly when occurring early in the disease course and at a high allelic burden. Here, we will review the prevalence and characteristics of somatic alterations in AA and PNH and will explore their prognostic significance and mechanisms of clonal selection. We will then discuss the available data on post-AA and post-PNH progression to secondary MDS/AML and provide practical guidance for approaching patients with PNH and AA who have CH.

Comparison of efficacy and health-related quality of life of first-line haploidentical hematopoietic stem cell transplantation with unrelated cord blood infusion and first-line immunosuppressive therapy for acquired severe aplastic anemia

We retrospectively compared the efficacy and health-related quality of life (HRQoL) of (1) first-line haploidentical hematopoietic stem cell transplantation (haplo-HSCT, n = 146) combined with unrelated cord blood (UCB) infusion and (2) first-line immunosuppressive therapy (IST, n = 219) in acquired severe aplastic anemia (SAA) patients. At 6 months post treatment, 90.30% patients in the haplo-HSCT group and 18.78% patients in the IST group achieved normal blood routine (P < 0.0001). The time required to discontinue red blood cells and platelets transfusion in the IST group were longer than in the haplo-HSCT group (P < 0.0001). The estimated overall survival at 4 years was similar (80.1 ± 3.5% vs. 80.1 ± 3.0%, P = 0.726); the estimated failure-free survival (FFS) at 4 years was 77.8 ± 3.7% in the haplo-HSCT group and 48.0 ± 3.6% in the IST group (P < 0.0001). Patients treated with haplo-HSCT scored significantly better in the HRQoL than treated with IST (P < 0.0001). In the multivariate analysis, first-line haplo-HSCT was the favorable factor for FFS and HRQoL (P < 0.0001). These results suggest that first-line haplo-HSCT combined with UCB infusion might provide a better chance of success and HRQoL than first-line IST for SAA patients.

[Prognostic factors of cyclosporine A combined with androgen in the treatment of transfusion dependent non-severe aplastic anemia]

Objective: To analyze the prognostic factors of transfusion-dependent non-severe aplastic anemia (TD-NSAA) patients treated with cyclosporine A (CsA) and androgen. Methods: Clinical data of 77 consecutive TD-NSAA patients treated with CsA and androgen were retrospectively analyzed between 2010 and 2013. We obtained clinical manifestations and baseline parameters of routine blood test from responders, and compared those with non-responders. All data were analyzed by univariate analysis and multivariate analysis. Results: In 77 patients, there were 43 (55.8%) patients achieved hematological response after 6 months'treatment, and 53 (68.8%) patients got response after 12 months. Univariate analysis showed that platelets baseline was the only factor related to hematological response [19 (6-61) ×10(9)/L vs 13.5 (5-45) ×10(9)/L, P=0.001] after 6 months therapy. After 12 months, the statistical differences were maintained, which were platelets baseline [18 (6-61) ×10(9)/L vs 10.5 (5-45) ×10(9)/L, P<0.001], absolute reticulocytes [0.03 (0.01-0.06) ×10(12)/L vs 0.029 (0.02-0.06) ×10(12)/L, P=0.043], transfusion-dependent of platelet (P=0.007) , transfusion-dependent of platelet and erythrocyte (P=0.012) . Multivariate analysis showed that platelets baseline could be an independent prognostic factor of hematological response (P=0.010 or 0.009) . Cutoff value of platelets by receiver operating characteristic curve was 15.5×10(9)/L. Conclusion: Baseline of higher platelets, higher reticulocyte, and no transfusion dependence of platelet are favorable prognostic factors. When platelets baseline is higher than 15.5×10(9)/L, CsA and androgen regimen is rational.

Comparison of frontline treatment with intensive immunosuppression therapy and HLA-haploidentical hematopoietic stem cell transplantation for young patients with severe aplastic anemia - A meta analysis

AIM

To compare the survivals and treatment related complications between immunosuppression therapy (IST) and haploidentical hematopoietic stem cell transplantation (haplo-HSCT) on children and young adults with severe aplastic anemia (SAA) in East Asia during the last 10 years.

METHODS

After looking through Pubmed, Embase, Web of Science and Wanfang Data, a total of 491 patients from 7 retrospective studies conducted in East-Asia were included for meta-analysis based on Stata program. Publication bias was measured by Begger and Egger tests. 1/3/5/10 years overall survivals (OS), failure free survivals (FFS), incidence rates of adverse events and their 95% confidence intervals (CI) were pooled and compared.

RESULTS

There was no difference of 1/3/5/10 years OS between IST group and haplo-HSCT group, but the 1/3/5/10 years FFS were significantly better in haplo-HSCT group compared with IST group (p < 0.01). However, higher incidence of infections was observed in haplo-HSCT group compared with IST group (76% versus 45%, p < 0.001). The pooled estimates for acute graft versus host disease (aGVHD) and chronic graft versus host disease (cGVHD) were 54% (95% Cl, 43%～64%) and 43% (95% CI, 18%～68%), respectively for haplo-HSCT group. Among them 38% (95%CI, 22%～54%) was grade III aGVHD and 11% (95% Cl, 0%～22%) was grade III-IV aGVHD. Death causes included severe infection, bleeding in IST group and infection, GVHD in haplo-HSCT group.

CONCLUSIONS

The long-term survivals were similar for young patients with SAA who received IST or haplo-HSCT as the frontline treatment. The haplo-HSCT group showed a better FFS, on the other hand, had higher incidence of infection and GVHD.

Activity of eltrombopag in severe aplastic anemia

Since the approval of horse antithymocyte globulin (ATG) decades ago, there was a long hiatus in therapies with activity in severe aplastic anemia (SAA). This scenario changed in 2014 when eltrombopag, a thrombopoietin receptor agonist, was approved for SAA after an insufficient response to initial immunosuppressive therapy (IST). The basis for this approval was the observation of single-agent activity of eltrombopag in this patient population, where 40% to 50% recovered blood counts at times involving >1 lineage. The achievement of transfusion independence confirmed the clinical benefit of this approach. Increase in marrow cellularity and CD34+ cells suggested a recovery to a more functioning bone marrow. Further in its development, eltrombopag was associated with standard horse ATG plus cyclosporine in first line, producing increases in overall (at about 90%) and complete response rates (at about 40%) and leading to transfusion independence and excellent survival. Interestingly, best results were observed when all drugs were started simultaneously. The cumulative incidence of clonal cytogenetic abnormalities to date has compared favorably with the vast experience with IST alone in SAA. Longer follow-up will help in define these long-term risks. In this review, the development of eltrombopag in SAA will be discussed.

The Case for Upfront HLA-Matched Unrelated Donor Hematopoietic Stem Cell Transplantation as a Curative Option for Adult Acquired Severe Aplastic Anemia

The improved success of HLA-matched unrelated donor (MUD) hematopoietic stem cell transplantation (HSCT) for severe aplastic anemia (SAA) in recent decades has had an impact on the indications for and timing of this treatment modality. In the absence of a matched sibling donor (MSD), historically MUD HSCT was reserved as an option after failure to respond to at least 2 courses of immunosuppressive therapy (IST) in adults with SAA, but with improved outcomes over time, it is now considered following failure to respond to 1 course of IST. Recent national and international studies and guidelines now recommend upfront MUD HSCT as an option for children for whom an MUD is readily available, because outcomes are similar to those for MSD HSCT. Fludarabine-based conditioning and the use of in vivo T cell depletion with antithymocyte globulin or alemtuzumab has been associated with a reported overall survival (OS) of >85% in adult patients undergoing MUD HSCT. However, the recent introduction of eltrombopag for patients with SAA has transformed the treatment landscape, and there is currently much interest in its use with IST as upfront treatment, which showed a high response rate in an early-phase study. The risks of HSCT, especially graft-versus-host disease (GVHD), need to be carefully balanced against the concerns of IST, namely relapse and later clonal evolution to myelodysplastic syndrome (MDS)/acute myelogenous leukemia (AML). In the absence of a current prospective randomized trial comparing these 2 approaches, in this review we examine the evidence supporting consideration of early MUD HSCT in adults with SAA who would have been considered for MSD HSCT but who lack a MSD and for whom an MUD is readily available, especially using an irradiation-free conditioning regimen, with a low risk of GVHD, as another treatment option. This option may be offered to patients to provide them with an informed choice, with the aim of curing disease rather than achieving freedom from disease, relapse-free survival, or OS. Furthermore, understanding the immune signature for the response to IST and the immunologic responses to somatic mutations and clonal progression to MDS/AML may help define the future indications for upfront HSCT and a more precise medical approach to therapy.

Immunosuppressive therapy for pediatric aplastic anemia: a North American Pediatric Aplastic Anemia Consortium study

Quality of response to immunosuppressive therapy and long-term outcomes for pediatric severe aplastic anemia remain incompletely characterized. Contemporary evidence to inform treatment of relapsed or refractory severe aplastic anemia for pediatric patients is also limited. The clinical features and outcomes for 314 children treated from 2002 to 2014 with immunosuppressive therapy for acquired severe aplastic anemia were analyzed retrospectively from 25 institutions in the North American Pediatric Aplastic Anemia Consortium. The majority of subjects (n=264) received horse anti-thymocyte globulin (hATG) plus cyclosporine (CyA) with a median 61 months follow up. Following hATG/CyA, 71.2% (95%CI: 65.3,76.6) achieved an objective response. In contrast to adult studies, the quality of response achieved in pediatric patients was high, with 59.8% (95%CI: 53.7,65.8) complete response and 68.2% (95%CI: 62.2,73.8) achieving at least a very good partial response with a platelet count ≥50×10⁹L. At five years post-hATG/CyA, overall survival was 93% (95%CI: 89,96), but event-free survival without subsequent treatment was only 64% (95%CI: 57,69) without a plateau. Twelve of 171 evaluable patients (7%) acquired clonal abnormalities after diagnosis after a median 25.2 months (range: 4.3-71 months) post treatment. Myelodysplastic syndrome or leukemia developed in 6 of 314 (1.9%). For relapsed/refractory disease, treatment with a hematopoietic stem cell transplant had a superior event-free survival compared to second immunosuppressive therapy treatment in a multivariate analysis (HR=0.19, 95%CI: 0.08,0.47; P=0.0003). This study highlights the need for improved therapies to achieve sustained high-quality remission for children with severe aplastic anemia.

Severe aplastic anemia: allogeneic bone marrow transplantation as first-line treatment

Treatment of severe aplastic anemia has improved significantly over the past 4 decades. This review will summarize the key areas of progress in the use of allogeneic hematopoietic cell transplantation and nontransplant immunosuppressive therapy (IST) for the treatment of aplastic anemia and then summarize the recommendations for first-line treatment. Based on recent data, we argue that guidelines for the initial treatment of patients with newly diagnosed severe aplastic anemia require revision. At the time of diagnosis, before beginning treatment, HLA typing should be done to identify a marrow donor among family members or in the unrelated donor registries, and a marrow transplant should be considered first-line therapy. The priority order of donor source for bone marrow transplantation is: (1) HLA-identical sibling, (2) HLA-matched unrelated donor, and (3) HLA-haploidentical donor if an HLA-matched unrelated donor is not rapidly available. Each of these donor marrow sources may be preferable to nontransplant IST. We make this recommendation because of the long-term persistent risk for disease relapse and secondary myelodysplastic syndrome or acute myeloid leukemia with the use of nontransplant IST for patients with aplastic anemia. In contrast, marrow transplantation is associated with high cure rates of aplastic anemia and a relatively low risk for graft-versus-host disease, with many patients now living for decades without the risk for disease recurrence or the development of clonal disorders. Implementation of this first-line treatment strategy will provide patients with severe aplastic anemia the best chance of long-term disease-free survival.

Eltrombopag maintains human hematopoietic stem and progenitor cells under inflammatory conditions mediated by IFN-γ

The proinflammatory cytokine interferon-γ (IFN-γ) has been implicated in human hematopoietic stem and progenitor cell (HSPC) depletion in immune-mediated bone marrow failure syndromes. We show that IFN-γ specifically prevents full engagement of thrombopoietin (TPO), a primary positive regulator of HSPC survival, to its receptor (c-MPL) via steric occlusion of the low-affinity binding site, contributing to perturbation of TPO-induced signaling pathways and decreased survival of human HSPCs. Eltrombopag, a synthetic small molecule mimetic of TPO that interacts with c-MPL at a position distinct from the extracellular binding site of TPO, bypasses this inhibition, providing an explanation for its clinical activity in bone marrow failure, despite already elevated endogenous TPO levels. Thus, IFN-γ-mediated perturbation of TPO:c-MPL complex formation and the resulting inhibition of a critical pathway of growth factor cell signaling may represent a general mechanism by which IFN-γ impairs the function of human HSPCs. This understanding could have broad therapeutic implications for various disorders of chronic inflammation.

Pathogenesis of Acquired Aplastic Anemia and the Role of the Bone Marrow Microenvironment

Aplastic anemia (AA) is characterized by bone marrow (BM) hypocellularity, resulting in peripheral cytopenias. An antigen-driven and likely auto-immune dysregulated T-cell homeostasis results in hematopoietic stem cell injury, which ultimately leads to the pathogenesis of the acquired form of this disease. Auto-immune and inflammatory processes further influence the disease course as well as response rate to therapy, mainly consisting of intensive immunosuppressive therapy and allogeneic hematopoietic cell transplantation. Bone marrow hematopoietic stem and progenitor cells are strongly regulated by the crosstalk with the surrounding microenvironment and its components like mesenchymal stromal cells, also consistently altered in AA. Whether latter is a contributing cause or rather consequence of the disease remains an open question. Overall, niche disruption may contribute to disease progression, sustain pancytopenia and promote clonal evolution. Here we review the existing knowledge on BM microenvironmental changes in acquired AA and discuss their relevance for the pathogenesis and therapy.

Activity of eltrombopag in severe aplastic anemia

Since the approval of horse antithymocyte globulin (ATG) decades ago, there was a long hiatus in therapies with activity in severe aplastic anemia (SAA). This scenario changed in 2014 when eltrombopag, a thrombopoietin receptor agonist, was approved for SAA after an insufficient response to initial immunosuppressive therapy (IST). The basis for this approval was the observation of single-agent activity of eltrombopag in this patient population, where 40% to 50% recovered blood counts at times involving >1 lineage. The achievement of transfusion independence confirmed the clinical benefit of this approach. Increase in marrow cellularity and CD34+ cells suggested a recovery to a more functioning bone marrow. Further in its development, eltrombopag was associated with standard horse ATG plus cyclosporine in first line, producing increases in overall (at about 90%) and complete response rates (at about 40%) and leading to transfusion independence and excellent survival. Interestingly, best results were observed when all drugs were started simultaneously. The cumulative incidence of clonal cytogenetic abnormalities to date has compared favorably with the vast experience with IST alone in SAA. Longer follow-up will help in define these long-term risks. In this review, the development of eltrombopag in SAA will be discussed.

Addition of eltrombopag to immunosuppressive therapy in patients with newly diagnosed aplastic anemia

BACKGROUND

The immune-mediated destruction of hematopoietic stem cells is implicated in the pathophysiology of aplastic anemia (AA). Immunosuppressive therapy (IST) using antithymocyte globulin and cyclosporine is successful in this setting. Eltrombopag is active in patients with refractory AA, presumably by increasing the bone marrow progenitors.

METHODS

This phase 2 trial initially was designed to evaluate standard IST in newly diagnosed patients with severe AA and later was amended to add eltrombopag to simultaneously address immune destruction and stem cell depletion. The primary outcome was the overall response rate (ORR) at 3 months and 6 months.

RESULTS

A total of 38 patients were enrolled: 17 (45%) received IST alone and 21 (55%) received additional eltrombopag. The ORR was 74%. Patients receiving IST plus eltrombopag had a similar ORR (76% vs 71%; P = .72), complete remission rate (38% vs 29%; P = .73), and median time to response (84 days vs 57 days; P = .30) compared with those receiving IST alone. The 2-year overall survival rate in the IST group was 91% compared with 82% for those patients treated with IST plus eltrombopag (P = .82). No cumulative toxicities were noted after the addition of eltrombopag.

CONCLUSIONS

The addition of eltrombopag to standard IST was well tolerated and resulted in similar responses.

Nationwide survey on the use of horse antithymocyte globulins (ATGAM) in patients with acquired aplastic anemia: A report on behalf of the French Reference Center for Aplastic Anemia

Antithymocyte globulins (ATG) plus cyclosporine (CSA) is the gold standard immunosuppressive treatment (IST) for patients with aplastic anemia. A prospective randomized trial showed in 2011 that hATG was superior to rabbit ATG for first-line treatment of severe AA. The French Health Agency (ANSM) permitted a patient-named authorization for temporary use (ATU) program of hATG (ATGAM, Pfizer) in patients with AA in 2011 since commercial access to hATG is not approved. We took advantage of this program to analyze the outcomes of 465 patients who received antithymocyte globulins (ATGAM) plus CSA as first line treatment (n = 379; 81.5%), or for refractory (n = 26) or relapsed disease (n = 33), from September 2011 to March 2017. In the entire cohort one year, 72% of the patients had partial and 13% had complete response, with worse response for patients with severe AA and a longer interval between diagnosis and IST (more than 6 months). Severe adverse events were mainly linked to infections (24%), hemorrhages (6%), and elevated liver function tests (5%). Overall at 12 months, 9.7% of patients required second line IST and 15.6% received transplantation. Fifty-five patients died during the study mainly because of infections (53%). Factors predicting independently worse survival were age over 40 years, neutrophils less than 0.5 × 10⁹ /L, male gender and longer delay between diagnosis and hATG (>6 months period). This study does illustrate the results of ATGAM with CSA in a true-life perspective and confirms ATGAM as standard of care IST to treat patients with AA not eligible for HSCT.

First-line choice for severe aplastic anemia in children: Transplantation from a haploidentical donor vs immunosuppressive therapy

We retrospectively compared the outcomes of children with severe aplastic anemia (SAA) who received immunosuppressive therapy (IST) or who underwent hematopoietic stem cell transplantation (HSCT) from a haploidentical donor (HID), between 2007 and 2016. A total of 52 children with SAA under the age of 17 years were initially treated with IST (n = 24) or haploidentical HSCT (n = 28) as first-line treatment. The estimated 10-year overall survival was 73.4 ± 12.6% and 89.3 ± 5.8% in patients treated with IST or HID-HSCT (P = .806). The failure-free survival was significantly inferior in patients receiving IST than in those undergoing transplantation from an HID (52.6 ± 10.5% vs 89.3 ± 5.8, P = .008). In univariate and multivariate analysis, the choice of first-line immunosuppressive therapy was the only adverse predictor for failure-free survival. At the last follow-up, completely normal blood count was observed in 11 of 20 (55.0%) and 24 of 25 (96.0%) live cases in IST and HID-HSCT cohort (P = .003). These suggest that HSCT from a haploidentical donor could be considered as first-line treatment in children who lack a matched related donor, especially in experienced transplantation centers.

Efficacy and safety of combined immunosuppressive therapy plus umbilical cord blood infusion in severe aplastic anemia patients: A cohort study

The present study aimed to evaluate the efficacy and safety of combined immunosuppressive therapy (IST) plus umbilical cord blood infusion (UCBI) in severe aplastic anemia (SAA) patients. A total of 68 patients with SAA were enrolled in the current prospective cohort study and divided into the IST (n=35; positive control) and IST+UCBI (n=33; experimental) groups according to the treatment conditions. Patients in the IST group were treated with rabbit antithymocyte globulin (r-ATG) at a dose of 2.5 mg/kg through intravenous infusion once a day for five days. This was combined with oral cyclosporine A (CsA) at a dose of 3–5 mg/kg twice a day for 2 years. Patients in the IST+UBCI group were treated with r-ATG and CsA at the same doses and frequencies as the IST group plus one UCBI 1 day after the final treatment with r-ATG. At 6 months post treatment, the complete response and overall response rate (ORR) of the IST+UCBI group were markedly higher compared with those in the IST group. Furthermore, patients in the IST+UCBI group achieved absolute neutrophil count (ANC) and platelet count responses more rapidly as compared with the IST group. However, no difference in the hemoglobin (Hb) response was identified between the two groups. In addition, SAA patients achieved responses in the ANC and platelet count more rapidly in comparison with very severe aplastic anemia (VSAA) patients, while the number of days to Hb responses were similar in the SAA and VSAA patients. Multivariate logistic regression analysis also revealed that IST+UCBI treatment was an independent predicting factor for patients achieving complete response or partial response, whereas VSAA was an independent predictor of a worse ORR. Platelet and reticulocyte were also independent predicting factors. Finally, the survival of patients was similar between the groups, and no difference in the safety of the treatment was observed. In conclusion, combined IST plus UCBI treatment may be applied as an effective and safe therapy for SAA patients.

Diagnosis and Treatment of Aplastic Anemia

OPINION STATEMENT

Acquired aplastic anemia (AA) is a rare, life-threatening bone marrow failure (BMF) disorder that affects patients of all ages and is caused by lymphocyte destruction of early hematopoietic cells. Diagnosis of AA requires a comprehensive approach with prompt evaluation for inherited and secondary causes of bone marrow aplasia, while providing aggressive supportive care. The choice of frontline therapy is determined by a number of factors including AA severity, age of the patient, donor availability, and access to optimal therapies. For newly diagnosed severe aplastic anemia, bone marrow transplant should be pursued in all pediatric patients and in younger adult patients when a matched sibling donor is available. Frontline therapy in older adult patients and in all patients lacking a matched sibling donor involves immunosuppressive therapy (IST) with horse antithymocyte globulin and cyclosporine A. Recent improvements in upfront therapy include encouraging results with closely matched unrelated donor transplants in younger patients and the emerging benefits of eltrombopag combined with initial IST, with randomized studies underway. In the refractory setting, several therapeutic options exist, with improving outcomes of matched unrelated donor and haploidentical bone marrow transplantation as well as the addition of eltrombopag to the non-transplant AA armamentarium. With the recent appreciation of frequent clonal hematopoiesis in AA patients and with the growing use of next-generation sequencing in the clinic, utmost caution should be exercised in interpreting the significance of somatic mutations in AA. Future longitudinal studies of large numbers of patients are needed to determine the prognostic significance of somatic mutations and to guide optimal surveillance and treatment approaches to prevent long-term clonal complications.

Resolution of acute hepatitis B-associated aplastic anaemia with antiviral therapy

A previously healthy 44-year-old woman presented with 3 days of worsening petechial rash, epistaxis and fatigue. Admission labs revealed pancytopenia, low reticulocyte index and elevated liver enzymes. Bone marrow biopsy demonstrated a profoundly hypocellular bone marrow without dysplasia and additional testing demonstrated an acute hepatitis B infection. In the context of an acute hepatitis B infection, elevated liver enzymes and aplastic anaemia, our patient was diagnosed with severe hepatitis-associated aplastic anaemia due to an acute hepatitis B infection. She was initiated on antiviral therapy with tenofovir and briefly received immunosuppressive therapy with a robust sustained improvement in her blood counts. Acute hepatitis B-associated aplastic anaemia is an exceptionally rare presentation of aplastic anaemia. We present acute hepatitis B-associated aplastic anaemia that resolved with antiviral therapy, which to our knowledge is the second such case reported in the literature and the first using tenofovir.

Incidence and outcome of acquired aplastic anemia: real-world data from patients diagnosed in Sweden from 2000-2011

A plastic anemia is a rare life-threatening disease. However, since the introduction of immunosuppressive therapy and allogeneic stem cell transplantation, the outcome has improved considerably, and the 5-year survival is reported to be 70–80% in selected patient cohorts. Yet, contemporary population-based data on incidence and survival are lacking. We performed a national retrospective study to determine the incidence, treatment, and survival of patients with aplastic anemia diagnosed in Sweden from 2000–2011. Patients were included via the National Patient Registry, and diagnosed according to the Camitta criteria. In total, 257 confirmed cases were identified, with an overall incidence of 2.35 (95% CI: 2.06–2.64) cases per million inhabitants per year. Median age was 60 years (range: 2–92), and median follow up was 76 (0–193) months. Primary treatments included immunosuppressive therapy (63%), allogenic stem cell transplantation (10%), or single-agent cyclosporine/no specific therapy (27%). The 5-year survival was 90.7% in patients aged 0–18 years, 90.5% in patients aged 19–39 years, 70.7% in patients aged 40–59 years, and 38.1% in patients aged ≥60 years. Multivariate analysis showed that age (both 40–59 and ≥60 age groups), very severe aplastic anemia and single-agent cyclosporine/no specific therapy were independent risk factors for inferior survival. In conclusion, younger aplastic anemia patients experience a very good long-term survival, while that of patients ≥60 years in particular remains poor. Apparently, the challenge today is to improve the management of older aplastic anemia patients, and prospective studies to address this medical need are warranted.

Human embryonic stem cell therapy for aplastic anemia

Human embryonic stem cell (hESC) therapy is the potential therapeutic option for the treatment of patients with aplastic anemia (AA). The study showed a remarkable improvement in the AA patient subsequent to hESC administration. No adverse events occurred in the patient. hESC therapy is safe and effective for AA patients.