First line treatment of aplastic anemia with thymoglobuline in Europe and Asia: Outcome of 955 patients treated 2001-2012

The state of the art in the treatment of severe aplastic anemia: immunotherapy and hematopoietic cell transplantation in children and adults

Acquired aplastic anemia (AA) is an immune-mediated bone marrow (BM) failure where marrow disruption is driven by a cytotoxic T-cell-mediated autoimmune attack against hematopoietic stem cells. The key diagnostic challenge in children, but also in adults, is to exclude the possible underlying congenital condition and myelodysplasia. The choice of treatment options, either allogeneic hematopoietic cell transplantation (alloHCT) or immunosuppressive therapy (IST), depends on the patient's age, comorbidities, and access to a suitable donor and effective therapeutic agents. Since 2022, horse antithymocyte globulin (hATG) has been available again in Europe and is recommended for IST as a more effective option than rabbit ATG. Therefore, an update on immunosuppressive strategies is warranted. Despite an improved response to the new immunosuppression protocols with hATG and eltrombopag, some patients are not cured or remain at risk of aplasia relapse or clonal evolution and require postponed alloHCT. The transplantation field has evolved, becoming safer and more accessible. Upfront alloHCT from unrelated donors is becoming a tempting option. With the use of posttransplant cyclophosphamide, haploidentical HCT offers promising outcomes also in AA. In this paper, we present the state of the art in the management of severe AA for pediatric and adult patients based on the available guidelines and recently published studies.

A multicentre ambispective observational study into the incidence and clinical management of aplastic anaemia in Spain (IMAS study)

Aplastic anemia (AA) is a rare, life-threatening hematological disease, with a poorly defined incidence. As the data available on AA varies substantially worldwide, a multicenter, ambispective, observational study was carried out between 2010 and 2019 to assess the incidence, clinical management and survival of AA at seven Spanish hospitals. The incidence of AA was 2.83 per million inhabitants per year, consistent with that reported previously in Europe, with a median age at diagnosis of 61 years-old (range 12-86), and a similar number of males and females. The initial diagnosis was severe or very severe AA in 55.8% of cases and 93.7% required transfusion. The most frequent first line therapy was anti-thymocyte globulin (ATG) plus cyclosporin A (CsA, 44.2%), followed by other CsA-based regimes (46.3%), with hematopoietic stem cell transplantation an infrequent 1st line therapy. The 6-month response rate was 68.2%, which then increased over a median follow-up of 3.9 years. The 5-year overall survival (5OS) was 73.6%, similar in severe (78.6%) and very severe AA patients (74.6%) but lower in moderate AA (MAA) patients (68.4%). The 5OS was 100% in 0-25 year-old patients but dropping to 58.3% in patients ≥ 60 years-old. At the last contact, 75.8% of the patients were alive. In conclusion, the incidence, characteristics and management of AA in our study are consistent with that reported previously. In terms of survival, although the global long-term OS rate was good, there is room for improvement, particularly in older patients. Finally, what appears to be a worse long-term survival of MAA patients, as reported previously, reinforces the importance of not underestimating this condition when diagnosed as MAA.

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.

Prolonged use of eltrombopag in patients with severe aplastic anemia in the real world

Eltrombopag (EPAG) can improve the efficacy of immunosuppressive therapy (IST) consisting of antithymocyte immunoglobulin (ATG) and cyclosporin in severe aplastic anemia (SAA) patients. This study explored whether patients with SAA could benefit from continuous usage of EPAG beyond 6 months.Seventy-four treatment-naive Chinese patients with SAA were administrated with rabbit ATG-based IST plus EPAG for 6 months. Patients not achieving complete remission (CR) at 6 months were treated with EPAG for another 6 months.At 1, 3, 6 and 12 months after IST, the cumulative response rates were 31%, 61%, 82% and 90%, and the cumulative CR rates were 0, 14%, 27% and 45%, respectively. The cumulative effect curve showed that 93% and 53% of all remission and CR occurred within 6 months, while 98% and 83% of all remission and CR occurred within 12 months. Thirty-seven percent of patients (11 of 30) with partial remission (PR) at 6 months continuously exposed to EPAG improved to CR within 3 (1-5) months of the extended median time. Six patients failing at 6 months continued to use EPAG. Three patients showed improved responses with an extended median time of 6 (1-6) months. The 2-year event-free survival (EFS) was better in those continuing with EPAG (89% vs. 49%, P = 0.006) for patients with PR or non-remission at 6 months.Continuous administration with EPAG could improve the hematologic response and EFS in patients without achieving CR at 6 months.This trial has been registered at the Chinese Clinical Trial Registry (ChiCTR2100045895).

Eltrombopag with or without Tacrolimus for relapsed/refractory acquired aplastic anaemia: a prospective randomized trial

This trial compared eltrombopag (EPAG)+tacrolimus and EPAG monotherapy in patients with refractory/relapsed acquired aplastic anaemia (AA). Patients with refractory/relapsed AA were randomly assigned to receive either EPAG+tacrolimus or EPAG monotherapy at a ratio of 2:1. Patient response, safety, clonal evolution and survival were compared. In total, 114 patients were included in the analysis, with 76 patients receiving EPAG+tacrolimus and 38 receiving EPAG only. With a median follow-up of 18 (6-24) months, the overall response rate (ORR) for patients treated with EPAG+tacrolimus and EPAG alone was 38.2% vs. 31.6% (P = 0.490) at the 3rd month, 61.8% vs. 39.5% (P = 0.024) at the 6th month, 64.5% vs. 47.1% (P = 0.097) at the 12th month, and 60.5% vs. 34.2% (P = 0.008) at the last follow-up. The rate of each adverse event, overall survival curves (P = 0.635) and clonal evolution rate (P = 1.000) were comparable between the groups. A post hoc subgroup analysis showed that EPAG+tacrolimus could have advantage over EPAG monotherapy in terms of the ORR at the 6th month (P = 0.030)/last follow-up (P = 0.013) and the cumulative relapse-free survival (RFS) curves (P = 0.048) in patients <60 years old.

Responders to low-dose ATG induce CD4+ T cell exhaustion in type 1 diabetes

BACKGROUNDLow-dose anti-thymocyte globulin (ATG) transiently preserves C-peptide and lowers HbA1c in individuals with recent-onset type 1 diabetes (T1D); however, the mechanisms of action and features of the response remain unclear. Here, we characterized the post hoc immunological outcomes of ATG administration and their potential use as biomarkers of metabolic response to therapy (i.e., improved preservation of endogenous insulin production).METHODSWe assessed gene and protein expression, targeted gene methylation, and cytokine concentrations in peripheral blood following treatment with ATG (n = 29), ATG plus granulocyte colony-stimulating factor (ATG/G-CSF, n = 28), or placebo (n = 31).RESULTSTreatment with low-dose ATG preserved regulatory T cells (Tregs), as measured by stable methylation of FOXP3 Treg-specific demethylation region (TSDR) and increased proportions of CD4+FOXP3+ Tregs (P < 0.001) identified by flow cytometry. While treatment effects were consistent across participants, not all maintained C-peptide. Responders exhibited a transient rise in IL-6, IP-10, and TNF-α (P < 0.05 for all) 2 weeks after treatment and a durable CD4+ exhaustion phenotype (increased PD-1+KLRG1+CD57- on CD4+ T cells [P = 0.011] and PD1+CD4+ Temra MFI [P < 0.001] at 12 weeks, following ATG and ATG/G-CSF, respectively). ATG nonresponders displayed higher proportions of senescent T cells (at baseline and after treatment) and increased methylation of EOMES (i.e., less expression of this exhaustion marker).CONCLUSIONAltogether in these exploratory analyses, Th1 inflammation-associated serum and CD4+ exhaustion transcript and cellular phenotyping profiles may be useful for identifying signatures of clinical response to ATG in T1D.TRIAL REGISTRATIONClinicalTrials.gov NCT02215200.FUNDINGThe Leona M. and Harry B. Helmsley Charitable Trust (2019PG-T1D011), the NIH (R01 DK106191 Supplement, K08 DK128628), NIH TrialNet (U01 DK085461), and the NIH NIAID (P01 AI042288).

Decision analysis of allogeneic bone marrow transplantation versus immunosuppressive therapy for young adult patients with aplastic anemia

BACKGROUND

Allogeneic bone marrow transplantation (BMT) from an HLA-matched sibling donor is recommended as an initial treatment for young patients. However, immunosuppressive therapy (IST) with cyclosporine and anti-thymocyte globulin may be a viable option even when an HLA-identical sibling donor is available.

METHODS

We constructed a Markov model to simulate the 10-year clinical course of patients aged 21-40 years with newly diagnosed severe aplastic anemia. Immediate BMT and IST were compared as an initial treatment assuming the availability of an HLA-identical sibling donor. Transition probabilities after treatment were determined based on a registry data analysis for BMT and a long-term prospective study for IST.

RESULTS

Quality-adjusted life years (QALYs) after treatment selection were 6.77 for BMT and 6.74 for IST. One-way sensitivity analysis revealed that the utility for being alive without GVHD after BMT, that for being alive with partial response after IST, and the response rate after initial IST strongly affected the results.

CONCLUSIONS

BMT and IST produced similar QALY for young patients with severe aplastic anemia. An estimation of the response rate to the initial IST may enable an individualized comparison between BMT and IST.

Whole-exome sequencing identifies FANC heterozygous germline mutation as an adverse factor for immunosuppressive therapy in Chinese aplastic anemia patients aged 40 or younger: a single-center retrospective study

Acquired aplastic anemia (AA) is a bone marrow failure disorder characterized by pancytopenia, and immunosuppressive therapy (IST) is the optional first-line management. Several studies identified the influencing factors on IST response; however, there are still a considerable number of patients suffering from poor prognoses. In this study, we enrolled 61 AA patients aged ≤ 40 years old, and whole-exome sequencing (WES) found unexpected high FANC heterozygous germline mutations (28/61, 45.9%). Patients with FANC mutations have a significantly lower absolute reticulocyte count and CD34⁺ % in the bone marrow and also lower 3-, 6-, and 9-month IST response than that without mutation, which were 0% vs. 25% (P = 0.017), 26.3% vs. 42.1% (P = 0.495), and 29.4% vs. 72.2% (P = 0.011), especially in anti-thymocyte globulin combined with the cyclosporin A (ATG + CsA) group, which were 0% vs.33.4% (P = 0.143), 25% vs.83.3% (P = 0.103), and 25% vs. 100% (P = 0.003), respectively. The event-free survival in the FANC^wt group was also better than that in the FANC^mut group (P = 0.016) and also showed in patients who received ATG + CsA treatment (P = 0.045). In addition, all the adverse effects of FANC germline mutation were not significant in stem cell-transplanted group. Our result indicated that the WES-based detection of FANC heterozygous germline mutations may have a great meaning in predicting IST response of acquired AA. This study was registered at chictr.org.cn (# ChiCTR2100054992).

[Clinical characteristics and prediction model of early death in severe/very severe aplastic anemia with immunosuppressive therapy]

Objective: Early death (ED) characteristics and predictive factors analysis in patients with severe/very severe aplastic anemia (SAA/VSAA) treated with intensive immunosuppression therapy and establish an ED prediction model. Methods: The clinical data of 232 patients with SAA/VSAA treated with Antithymocyte immunoglobulin (ATG) at the Peking Union Medical College Hospital from August 2003 to August 2021 were collected. The characteristics and causes of ED within 90 days were analyzed retrospectively. Cox proportional hazards model was used to screen the ED risk factors and build a prediction model. Results: Only 19 patients (8.2% ) developed ED with a median time of 24 (3-85) days among the 232 patients with SAA/VSAA who received ATG treatment. The main cause of ED was infection (84.2% ) , followed by cerebral hemorrhage (10.5% ) . Multivariate analysis showed that VSAA (HR=15.359, 95% CI 1.935-121.899, P=0.010) , fungal infection prevention by posaconazole (HR=0.147, 95% CI 0.019-1.133, P=0.066) , lymphocyte count (LYM) ≤ 0.5×10(9)/L (HR=3.386, 95% CI 1.123-10.206, P=0.030) , and PLT ≤ 5×10(9)/L (HR=8.939, 95% CI 1.948-41.019, P=0.005) were ED's independent influencing factors. To build a clinical prediction model, VSAA, fungal infection prevention by posaconazole, LYM ≤ 0.5×10(9)/L, and PLT ≤ 5×10(9)/L were scored with 3, -2, 1, and 2, respectively. The integral model AUC=89.324 (95% CI 80.859-97.789) . The ED risk in patients with a score ≥ 3 was 23.1 (95% CI 5.3-100.2) times that in patients with a score<3. Conclusion: ED caused by infection and cerebral hemorrhage is an important challenge for SAA/VSAA to be treated with ATG. VSAA, LYM ≤ 0.5×10(9)/L, and PLT ≤ 5×10(9)/L patients who did not use posaconazole to prevent fungal infection had a high ED risk.

Aplastic Anemia as a Roadmap for Bone Marrow Failure: An Overview and a Clinical Workflow

In recent years, it has become increasingly apparent that bone marrow (BM) failures and myeloid malignancy predisposition syndromes are characterized by a wide phenotypic spectrum and that these diseases must be considered in the differential diagnosis of children and adults with unexplained hematopoiesis defects. Clinically, hypocellular BM failure still represents a challenge in pathobiology-guided treatment. There are three fundamental topics that emerged from our review of the existing data. An exogenous stressor, an immune defect, and a constitutional genetic defect fuel a vicious cycle of hematopoietic stem cells, immune niches, and stroma compartments. A wide phenotypic spectrum exists for inherited and acquired BM failures and predispositions to myeloid malignancies. In order to effectively manage patients, it is crucial to establish the right diagnosis. New theragnostic windows can be revealed by exploring BM failure pathomechanisms.

Apolipoprotein-A is a potential prognostic biomarker for severe aplastic anemia patients treated with ATG-based immunosuppressive therapy: a single-center retrospective study

Background

Anti-thymoglobulin (ATG)-based immunosuppressive treatment (IST) is the standard first-line management for patients with severe AA/very severe AA (SAA/VSAA) and is not suitable for allogeneic stem cell transplantation. The response predictor was not fully investigated.

Objective

The present study attempted to explore other characteristics, such as serum lipid changes, during ATG-based IST and analyzed their significance in predicting IST response and survival.

Methods

A total of 61 newly diagnosed SAA/VSAA patients who received ATG-based IST were enrolled from January 2011 to June 2019. The blood lipid levels, immunoglobulins, and peripheral T lymphocytes were retrospectively collected, and their correlations with IST response, estimated 8.5-year overall survival (OS) and event-free survival (EFS) were analyzed.

Results

The overall response (OR)/complete remission (CR) at 3, 6, and 9 months was 24.6%/6.6%, 52.5%/14.8%, and 65.6%/23.0%, respectively. Based on the 9-month response effect, patients were divided into IST-response (IST-R) and IST-nonresponse (IST-NR) groups. The subgroup baseline characteristics showed that the disease severity grade, absolute neutrophil granulocyte count (ANC), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and apolipoprotein-A (Apo-A) differed between the IST-R and IST-NR groups. Patients with lower Apo-A (< 1.205 g/L) level pretreatment had a better event-free survival (EFS), and a moderate negative correlation was established between the pretreatment Apo-A and 9-month response (P = 0.004). In addition, the T-cell subset and immunoglobulin analyses showed that the responsive patients had a low serum IgA level, which decreased further after therapy. Additionally, a moderate negative correlation was established between the 3-month IgA and 9-month response (P = 0.006).

Conclusion

Serum Apo-A is a prognostic biomarker for newly diagnosed < 60-year-old SAA/VSAA patients who received ATG-based IST (registered at chictr.org.cn as # ChiCTR2100052979).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12944-022-01703-0.

First-line immunosuppressive therapy with rATG and CsA for severe aplastic anemia: 15 years' experience

Rabbit antithymocyte globulin (rATG) instead of horse ATG has been used for severe aplastic anemia (SAA) patients in China. This study aimed to investigate the hematologic responses and long-term overall survival (OS) outcomes in SAA patients who received rATG and cyclosporine as first-line immunosuppressive therapy. We analyzed data of 542 SAA patients treated with this therapy between 2005 and 2019. The median age was 20 (range, 2-80) years, and the median follow-up time was 45.5 (range, 0.1-191.4) months. The early mortality rate was 3.9%. The overall response rates (ORRs) were 40.2%, 56.1%, and 62.4% at 3, 6, and 12 months, respectively. The 6- and 12-month ORR of patients treated with 3 mg/kg/d of rATG in 2015-2019 seemed higher than that of patients treated with 3.5-3.75 mg/kg/day in 2005-2014 (60.2% vs. 54.9%, P = 0.30 and 69.9% vs. 60.1%, P = 0.049, respectively). The 10-year cumulative incidences of relapse and clonal evolution were 10.6 ± 2.9% and 7.5 ± 1.5%, respectively. The 10-year OS rate and event-free survival rate were 80.1 ± 2.1% and 75.6 ± 3.7%, respectively. Age, disease severity, treatment periods, and the interval from diagnosis to IST were independent predictors of OS. In conclusion, 3 mg/kg/day rATG is effective as first-line treatment for SAA.

Predicting Response of Severe Aplastic Anemia to Rabbit-Antithymocyte Immunoglobulin Based Immunosuppressive Therapy Combined With Eltrombopag

Addition of eltrombopag (E-PAG) to intensive immunosuppressive therapy (IST) contributes to restoring hematopoiesis in patients with severe aplastic anemia (SAA). Used at relatively low doses in the East Asian population, the efficacies of E-PAG and the predictors for efficacy are not clear. We conducted a retrospective, multicenter study to analyze the efficacy and the possible predicting factors at 6 months in 58 adult SAA patients with rabbit ATG-based IST and E-PAG. The response rate and complete response rate at 6 months were 76% and 21%, respectively. The baseline reticulocyte percentage [area under a curve (AUC)=0.798, 95% confidence interval (CI) 0.640-0.956, P=0.006], absolute reticulocyte count (ARC) (AUC =0.808, 95%CI 0.647-0.970, P=0.004), red cell distribution width - coefficient of variation (RDW-CV) (AUC=0.722, 95%CI 0.494-0.950, P=0.040), and absolute lymphocyte count (ALC) (AUC=0.706, 95%CI 0.522-0.890, P=0.057) were highly predictive of response at 6 months. The tipping values of reticulocyte percentage, ARC, RDW-CV, and ALC were 0.45%, 7.36×10⁹/L, 11.75%, and 1.06×10⁹/L, respectively. The sensitivity and specificity of reticulocyte percentages were 81.6% and 66.7%; ARC were 86.8% and 66.7%, RDW-CV were 94.7% and 55.6%; ALC were 55.3% and 88.9%. At a median follow-up of 15.5 months, the 2-year cumulative overall survival was 92%. The baseline reticulocyte percentage, ARC, RDW-CV, and ALC were potential factors in predicting a favorable effect of rabbit-ATG based IST plus E-PAG in SAA patients of East Asia (ChiCTR2100045895).

Clinical Trial Registration

http://www.chictr.org.cn/edit.aspx?pid=125480&htm=4, identifier ChiCTR2100045895.

[Reassessing the six months prognosis of patients with severe or very severe aplastic anemia without hematological responses at three months after immunosuppressive therapy]

Objective: To reassess the predictors for response at 6 months in patients with severe or very severe aplastic anemia (SAA/VSAA) who failed to respond to immunosuppressive therapy (IST) at 3 months. Methods: We retrospectively analyzed the clinical data of 173 patients with SAA/VSAA from 2017 to 2018 who received IST and were classified as nonresponders at 3 months. Univariate and multivariate logistic regression analysis were used to evaluate factors that could predict the response at 6 months. Results: Univariate analysis showed that the 3-month hemoglobin (HGB) level (P=0.017) , platelet (PLT) level (P=0.005) , absolute reticulocyte count (ARC) (P<0.001) , trough cyclosporine concentration (CsA-C0) (P=0.042) , soluble transferrin receptor (sTfR) level (P=0.003) , improved value of reticulocyte count (ARC(△)) (P<0.001) , and improved value of soluble transferrin receptor (sTfR(△)) level (P<0.001) were related to the 6-month response. The results of the multivariate analysis showed that the PLT level (P=0.020) and ARC(△) (P<0.001) were independent prognostic factors for response at 6 months. If the ARC(△) was less than 6.9×10(9)/L, the 6-month hematological response rate was low, regardless of the patient's PLT count. Survival analysis showed that both the 3-year overall survival (OS) [ (80.1±3.9) % vs (97.6±2.6) %, P=0.002] and 3-year event-free survival (EFS) [ (31.4±4.5) % vs (86.5±5.3) %, P<0.001] of the nonresponders at 6 months were significantly lower than those of the response group. Conclusion: Residual hematopoietic indicators at 3 months after IST are prognostic parameters. The improved value of the reticulocyte count could reflect whether the bone marrow hematopoiesis is recovering and the degree of recovery. A second treatment could be performed sooner for patients with a very low ARC(△).

Diagnostic work-up for severe aplastic anemia in children: Consensus of the North American Pediatric Aplastic Anemia Consortium

The North American Pediatric Aplastic Anemia Consortium (NAPAAC) is a group of pediatric hematologist-oncologists, hematopathologists, and bone marrow transplant physicians from 46 institutions in North America with interest and expertise in aplastic anemia, inherited bone marrow failure syndromes, and myelodysplastic syndromes. The NAPAAC Bone Marrow Failure Diagnosis and Care Guidelines Working Group was established with the charge of harmonizing the approach to the diagnostic workup of aplastic anemia in an effort to standardize best practices in the field. This document outlines the rationale for initial evaluations in pediatric patients presenting with signs and symptoms concerning for severe aplastic anemia.

Platelet/Lymphocyte ratio independently predicts the outcome of severe aplastic anemia patients treated with antithymocyte globulin

OBJECTIVE

The aim of this study was to determine the clinical role of platelet/lymphocyte ratio and neutrophil/lymphocyte ratio in severe aplastic anemia patients treated with antithymocyte globulin.

METHODS

The outcomes of consecutive severe aplastic anemia patients treated with rabbit or swine antithymocyte globulin plus cyclosporine (n=159, from January 2012 to December 2018) were analyzed retrospectively.

RESULTS

In a total of 159 patients, the actuarial 5-year survival rate was 85.6%. Low platelet/lymphocyte ratio (PLR≤55) was significantly associated with less complications at 1 month and 24 months after the antithymocyte globulin treatment (p=0.048 and 0.028, respectively). The univariate and multivariate analyses revealed that low platelet/lymphocyte ratio was an independent predictor of overall survival (p=0.03 and 0.04, respectively). Patients with low neutrophil/lymphocyte ratio (NLR≤0.18) had shorter survival time, but there was no significant difference (p=0.056). PLR was positively correlated with neutrophil/lymphocyte ratio (r=0.38, p<0.0001) and age (r=0.17, p=0.0379), while it was negatively correlated with IgG level (r=-0.18, p=0.0309). The ratio of CD4/CD8 was significantly higher in low platelet/lymphocyte ratio group (p=0.005).

CONCLUSION

The platelet/lymphocyte ratio reflects the immune abnormality of SAA. Notably, low platelet/lymphocyte ratio is an independently positive prognostic factor for severe aplastic anemia patients treated with antithymocyte globulin.

Adult aplastic anemia in Thailand: incidence and treatment outcome from a prospective nationwide population-based study

The incidence and outcomes of aplastic anemia (AA) in Asia remain limited. This study aimed to explore the incidence and outcomes of patients with adult AA across the country of Thailand. This is a prospective multi-center nationwide population-based observational study of AA patients aged at least 15 years old, diagnosed from August 2014 to July 2016, with a longitudinal follow-up period over 2 years. There were 348 newly diagnosed adult AA patients during the enrollment period, giving an annual incidence of 4.6 per million. The incidence of severe (SAA) and very severe aplastic anemia (VSAA) (3.8 per million) was higher than non-severe AA (NSAA, 0.8 per million). The peak incidence was observed in the patients aged from 80 to 89 years old (14.4 per million). The 2-year overall survival (OS) in NSAA, SAA, and VSAA were 65.5%, 49.3%, and 20.1%, respectively (P < 0.001). With regard to the response to immunosuppressive therapy, the overall response rate (ORR) in SAA/VSAA treated with rabbit anti-thymocyte globulin with/without cyclosporin A (rATG ± CsA) were significantly superior to those treated with CsA alone, or anabolic steroids (44.4% vs 36.4% and 31.2%, respectively, P < 0.001). The 2-year OS in SAA/VSAA treated with rATG ± CsA, CsA, and anabolic steroids were 54.8%, 54.5%, and 37.6% (P = 0.037), respectively. The incidence of adult AA in Thailand is higher than those in Western countries, and the peak incidence is in the elderly. rATG ± CsA provided a better response than anabolic steroids, translating to the superior survival in SAA/VSAA treated with rATG ± CsA.

Hematopoietic Stem-Cell Transplantation versus Immunosuppressive Therapy in Patients with Adult Acquired Severe Aplastic Anemia: A Cost-Effectiveness Analysis

Objective

Controversy remains regarding which therapy to initially select for severe aplastic anemia (SAA) patients aged 35–50. This cost-effectiveness analysis aimed to use the Markov model to compare immunosuppressive therapy (IST) with hematopoietic stem-cell transplantation (HSCT) in age-stratified patients with SAA.

Methods

A cost-effectiveness analysis using a Markov model compared IST with HSCT in age-stratified patients with SAA. Baseline data were derived from a systematic literature review and collected from Huashan Hospital, Fudan University. The primary outcome was an incremental cost-effectiveness ratio (ICER).

Results

The HSCT strategy dominated in patients aged 18–35 even though it was $146,970 more expensive than IST, and the ICER of HSCT to IST was $14,054.19/quality-adjusted life-year (QALY), which was less than the willingness-to-pay value of $25,397.57/QALY. The IST strategy dominated in patients aged 35–50, because it was $72,009 less expensive than HSCT and yielded 3.24 QALYs more than HSCT. The model was vigorous in the sensitivity analyses of the key variables tested through the plausible ranges that were acquired from costing sources and previously published literature.

Conclusion

The preferred induction strategy for patients aged 18–35 with SAA appears to be HSCT, and the preferred strategy for patients aged 35–50 is IST, which minimizes costs while maximizing QALYs.

[Diagnosis and Therapy of aplastic anemia - update 2021]

The landscape of aplastic anemia (AA) is changing as new therapeutic options become available and sophistic diagnostics enable us to decipher various subgroups of bone marrow failure syndromes (BMFS) such as telomeropathies and other constitutional diseases with manifestations beyond childhood.This article briefly summarizes developments of the last few years with potential clinical impact and puts it into perspective. Focus is given to the growing list of inherited BMFS and the need to e. g. screen patients at all ages for telomeropathies before initiation of treatment as part of routine evaluation of AA. The usage of next generation sequencing (NGS) to differentiate between AA and malignancies such as myelodysplatic syndrome (MDS) and the need to watch out for potential clonal evolution during and after treatment is also briefly discussed. Recent data on combinations of immunosuppressive therapy (IST) with thrombopoietin receptor agonists (TRA) for patients with severe AA as well as newer data with TRA mono-therapy for patients with moderate AA are presented. Finally the importance of supportive measures, structures and quality of life aspects are highlighted.

Efficacy of Rabbit Antithymocyte Globulin as a First-line Therapy in Children With Aplastic Anemia

BACKGROUND

The efficacy, safety, and outcome of rabbit antihuman thymocyte globulin (rATG) as initial therapy for children aplastic anemia (AA) were evaluated.

PATIENTS AND METHODS

Sixty-one children with AA were retrospectively analyzed, including 43 patients with severe AA and 18 patients with transfusion-dependent nonsevere AA. All patients received rATG in combination with cyclosporine A between September 2005 and January 2015.

RESULTS

The overall response rates were 55.7%, 68.9%, and 68.9% at 6, 12, and 18 months, respectively. Surprisingly, the overall complete response rate kept increasing from 9.8% at 12 months to 39.3% at 18 months, indicating a delayed response for rATG. Overall survival at 5 and 10 years was 72.1% and 67.2%, respectively. The overall survival of patients who responded between 3 and 12 months was significantly higher than that of nonresponders (71.4% vs. 47.4%).Antithymocyte globulin-related adverse reactions were significantly higher in severe AA (83.7%) than in nonsevere AA (55.6%) and these reactions were controllable and not life threatening with comprehensive measures.

CONCLUSIONS

This retrospective study shows an encouraging response and survival results in children with AA treated with rATG. Prolonged assessments were needed to evaluate the delayed responses to rATG. rATG could be used as an alternative in the first-line treatment of childhood AA.

Long-term outcomes of 172 children with severe aplastic anemia treated with rabbit antithymocyte globulin and cyclosporine

This study retrospectively analyzed the clinical outcome of 172 children with newly diagnosed severe aplastic anemia (SAA) between January 2008 and April 2018, who received rabbit antithymocyte globulin (ATG) and cyclosporine (CsA) as first-line treatment. The median age at diagnosis was 5 years (range, 1-14). The overall response rates were 22.7%, 45.3%, and 61% at 40 days, 3 months, and 6 months, respectively, after rabbit ATG. In multivariate analysis, mild disease severity was the only predictor of favorable response at 6 months (P = 0.006). In the present study, median follow-up period was 63 months (range, 1-135). The 5-year overall survival (OS) and failure-free survival (FFS) rates were 90.5% and 70.4%. Multivariate analysis showed that erythroid burst-forming units (BFU-E) > 2/10⁵ bone marrow mononuclear cell (BMMNC) (P = 0.037) and time interval before IST ≤ 30 days (P = 0.017) were independent positive predictors for OS, meanwhile BFU-E > 2/10⁵BMMNC (P = 0.029) was the only favorable prognostic factor for FFS.

Long-term follow-up of a novel immunosuppressive strategy of cyclosporine alternatively combined with levamisole for severe aplastic anemia

Hematopoietic stem cell transplantation (HSCT) and immunosuppressive therapy (IST) with antithymocyte globulin (ATG) and cyclosporine (CsA) have been widely accepted as the standard first-line treatments for severe aplastic anemia (SAA). However, most of the patients with SAA had a slim chance to access these strategies in developing countries. Here, we reported 10-year results in a cohort of 232 patients with SAA who received a novel IST of CsA, levamisole, and danazol (CsA&LMS-based regimen). The cumulative incidence of response was 52.1% at 6 months, 66.4% at 12 months, and 77.1% at 24 months. The 10-year overall survival (OS) and failure-free survival was 60.2% and 48.3%, respectively. Positive predictors of OS in multivariate analysis were higher pretreatment ANC, younger age, higher pretreatment absolute reticulocyte count (ARC), and response within 6 months. The probability of CsA&LMS discontinuation was 50.2% at 10 years. With a slow CsA&LMS taper, the actuarial risk for relapse was only 9.5%. The cumulative incidence of MDS/AML was 8.2% at 10 years. The long-term follow-up information demonstrated that the CsA&LMS regimen could be a promising strategy for patients with SAA in developing countries.

Anti-thymocyte globulin in haematology: Recent developments

Anti-thymocyte globulin (ATG) is a polyclonal antiserum introduced into clinical medicine more than 30 years ago. It induces a broad non-specific immunosuppression. In haematology, standard indications are severe aplastic anaemia and prophylaxis and treatment of graft-versus-host disease (GVHD) (after allogeneic transplantation). For aplastic anaemia, ATG from horses has been found to be superior to ATG from rabbits. In the situation of allogeneic transplantation, ATG lessens the risk of chronic GVHD but may not improve survival. There is current controversy regarding which patients benefit most from ATG and what the ideal dosage is. It is likely that in the coming years a more specific immunosuppressive will be developed that will minimize GVHD while maintaining the graft-versus-malignancy effect.

Multivariate logistic analysis of predictors of response to immunosuppressive therapy in children with aplastic anemia: a double-center study

BACKGROUND

Immunosuppressive therapy (IST) composed of antithymocyte globulin (ATG) and cyclosporine A (CSA) is one of the standard therapies in pediatric patients with acquired aplastic anemia (AA), but predictors of IST are lack of consensus.

PROCEDURES

Ninety-four patients from two pediatric medical centers in China were included between January 2005 and March 2018. Clinical factors associated with the efficacy were analyzed according to multivariate logistic regression model previously established.

RESULTS

We discovered that overall responsiveness was 77.66%. Five out of 35 factors were statistically significant in univariate analysis. Based on the cutoff point chosen by receiver operating characteristic (ROC) curve, 5 continuous variables were made categorical, among which 3 variables with significance were employed to establish the logistic regression equation. Based on these 3 variables, we found that starting IST within 126 days of the first appearance of symptoms (X1, p = .003), absolute neutrophil count (ANC) higher than 0.435×10⁹/L (X2, p = .012), and rate of decreased actual lymphocyte count (ALC) higher than 59.2% within the 1st week after IST (X3, p = .001) were three independent risk factors for response to IST. The rate of decreased ALC higher than 59.2% after IST was the most significant variable (OR = 9.355, Log (P) = -2.161 + 2.149X1 + 1.662X2 + 2.236X3). The accuracy, sensitivity, and specificity of the model were 86.2%, 94.5% and 57.1%, respectively.

CONCLUSION

Duration of AA, ANC and decreased ALC rate after IST might predict the response to IST, among which the rate of decreased ALC after IST is the most important predictive factor.

Immunosuppressive therapy with rabbit antithymocyte globulin therapy for acquired aplastic anemia: a multi-institutional retrospective study in Japanese adult patients

We retrospectively analyzed efficacy and safety of therapy with rabbit antithymocyte globulin (rATG) in combination with cyclosporine A (CsA) in 30 Japanese adult patients with acquired aplastic anemia (AA) in the Kyoto Clinical Hematology Study Group. The median observation period was 31 months and the median age of the patients was 54 years. The objective response rates (ORRs) to rATG plus CsA increased over time until 18 months after the start of treatment; the rate of achievement of better than partial response at 18 months was 66.7%. The 2-year overall survival (OS) rate was 79% in all patients. In eight patients aged ≥ 75 years old, the ORR was 62.5% and the 2-year OS rate of 50% was not significantly inferior to that in patients aged ≤ 74 years old. The overall mortality rate was 16.7% in our cohort, while the mortality rate in patients aged ≥ 75 years old was 37.5%, which was higher than that in patients aged ≤ 74 years old (9.1%), although the difference was not statistically significant. Collectively, rATG combined with CsA is an effective and feasible treatment for AA, while patients should be appropriately selected.

First line treatment of aplastic anemia with thymoglobuline in Europe and Asia: Outcome of 955 patients treated 2001-2012

The aim of this study was to assess the outcome of patients with aplastic anemia (AA), receiving rabbit anti‐thymocyte globulin (Thymoglobulin, SANOFI) and cyclosporin, as first line treatment. Eligible were 955 patients with AA, treated first line with Thymoglobulin, between 2001 and 2008 (n = 492), or between 2009 and 2012 (n = 463). The median age of the patients was 21 years (range 1‐84). Mortality within 90 days was 5.7% and 2.4%, respectively in the two time periods (P = .007).The actuarial 10‐year survival for the entire population was 70%; transplant free survival was 64%. Predictors of survival in multivariate analysis, were severity of the disease, patients age and the interval between diagnosis and treatment. Survival was 87% vs 61% for responders at 6 months versus nonresponders (P < .0001). The 10‐year survival of nonresponders at 6 months, undergoing a subsequent transplant (n = 110), was 64%, vs 60% for patient not transplantated (n = 266) (P = .1). The cumulative incidence of response was 37%, 52%, 65% respectively, at 90, 180, and 365 days. In multivariate analysis, negative predictors of response at 6 months, were older age, longer interval diagnosis treatment, and greater severity of the disease. In conclusion, early mortality is low after first line treatment of AA with Thymoglobulin, and has been further reduced after year 2008. Patients age, together with interval diagnosis—treament and severity of the disease, remain strong predictors of response and survival.