Long-term outcome after immunosuppressive therapy with horse or rabbit antithymocyte globulin and cyclosporine for severe aplastic anemia in children

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.

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 Systematic Review and Meta-Analysis of Eltrombopag Efficacy Combined With Immunosuppressive Drugs in Treatment of Severe Aplastic Anemia

Severe aplastic anemia (SAA) is a life-threatening disorder with high mortality. The only curative treatment is hematopoietic stem cell transplantation (HSCT), but it is mainly for young patients with suitable donors. The alternative is immunosuppressive therapy (IST), which can improve blood counts in about 58% of patients, but many relapse after discontinuation. Recently, eltrombopag, a thrombopoietic receptor agonist, was tested. As a single drug, it improved blood counts in 40-50% of patients. However, combining eltrombopag and IST proved more effective and safer. A review of 20 randomized controlled trials with 2,469 patients showed that the group receiving eltrombopag and IST had a significantly higher overall response rate (86% vs. 74%) after six months. After two years, 54% of the experimental group had relapsed compared to 39% in the control group. Despite this, eltrombopag tends to increase relapse rates over time. In conclusion, combining eltrombopag with IST is a superior treatment for SAA.

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.

Relapse and transformation to myelodysplastic syndrome and acute myeloid leukemia following immunosuppressive therapy for aplastic anemia is more common as compared to allogeneic stem cell transplantation with a negative impact on survival

We studied the incidence of relapse, transformation to myelodysplastic syndrome/acute myeloid leukemia, and survival in patients with aplastic anemia (AA) surviving more than 1 year after ATG/ALG-based immunosuppressive therapy (IST) between 1985 and 2020. Four-hundred seventy patients (413 adults and 57 children) were studied, and data were compared with 223 patients who underwent matched sibling donor transplant (MSD HSCT). Median follow-up is 50 months (12-359). Relapse occurred in 21.9% at a median time of 33.5 months (5-228) post IST. Twenty-six (5.5%) patients progressed to PNH, while 20 (4.3%) evolved to MDS/AML. Ten-year estimated overall survival (OS) is 80.9 ± 3% and was significantly better in patients without an event (85.1 ± 4%) compared to relapse (74.6% ± 6.2%) or clonal evolution (12.8% ± 11.8%) (p = 0.024). While the severity of AA (p = 0.011) and type of ATG (p = 0.028) used predicted relapse, only age at IST administration influenced clonal evolution (p = 0.018). Among HSCT recipients, relapse rates were 4.9% with no clonal evolution, and the 10-year OS was 94.5 ± 2%. In patients who survived 1 year following IST, outcomes were good except with clonal evolution to MDS/AML. These outcomes, however, were still inferior compared to matched sibling donor HSCT.

Comparable outcomes with low-dose and standard-dose horse anti-thymocyte globulin in the treatment of severe aplastic anemia

BACKGROUND

The standard dose (SD) of horse anti-thymocyte globulin (hATG) ATGAM (Pfizer, USA) or its biosimilar thymogam (Bharat Serum, India) for the treatment of Aplastic Anemia (AA) is 40 mg/kg/day for 4 days in combination with cyclosporine. Data on the impact of hATG dose on long-term outcomes are limited. Here, we describe our comparative experience using 25 mg/kg/day (low-dose [LD]) hATG for 4 days with SD for the treatment of AA.

METHODS

We retrospectively studied patients with AA (age > 12 years) who received two doses of hATG combined with cyclosporine. Among 93 AA patients who received hATG, 62 (66.7%) and 31 (33.3%) patients received LD and SD hATG with cyclosporine, respectively. Among these,seventeen(18.2%) patients also received eltrombopag with hATG and cyclosporine. Overall response rates [complete response (CR) and partial response (PR)] of LD and SD hATG groups at 3 months (50% vs. 48.4%; p = 0.88), 6 months (63.8% vs. 71.4%; p = 0.67), and 12 months (69.6% vs. 79.2%; p = 0.167) were comparable. The mean (Standard Deviation) 5-year Kaplan-Meier estimate of overall survival and event-free survival was 82.1 (4.6)% and 70.9 (5.5)% for the study population. The mean (standard deviation) 5-year Kaplan-Meier estimate of overall survival and event-free survival of those who received LD hATG versus SD hATG dose was 82.9 (5·3)% versus 74.8 (10·3)% (P = 0·439), and 75.2 (6.2)% versus 61.4(11.2)% (P = 0·441).

CONCLUSION

Our study revealed that the response rates of patients with AA and LD were similar to those of patients with SD to hATG combined with cyclosporine in a real-world setting.

Natural killer cells in peripheral blood at diagnosis predict response to immunosuppressive therapy in severe aplastic anemia

Immunosuppressive therapy (IST) consisting of antihuman thymocyte globulin and cyclosporine A is the first-line therapy for patients with severe aplastic anemia (AA) who are ineligible for undergoing bone marrow transplantation. The aim of the study was to evaluate the correlation between natural killer (NK) cells and response to IST in SAA patients. We retrospectively included 93 AA patients and detected NK cells in peripheral blood by flow cytometry. Both the proportion and absolute number of NK cells in newly diagnosed SAA patients were significantly lower than in controls, while the proportion and absolute number of NK cells in complete remission patients treated with IST were remarkably increased compared with treatment-naïve SAA patients. Additionally, the absolute number of NK cells at diagnosis was positively correlated with initial blood counts. For SAA patients receiving IST, the proportion of NK cells at baseline and 6 months was significantly higher in responders than in non-responders. Unexpectedly, we found that the increase in the proportion of NK cells at 6 months after IST was closely related to the recovery of hematopoiesis. ROC curve identified 7.3% of NK cells proportion at diagnosis as the cutoff value to predict response to IST. The response rate was higher in NK proportion high group than in NK proportion low group. Multivariate logistic regression analysis further confirmed the independent predictive value of NK cells proportion in assessing IST response. The proportion of NK cells at diagnosis may serve as a promising predictor of response to IST in patients with SAA.

Elevated TCR-αβ+ double-negative T cells in pediatric patients with acquired aplastic anemia

BACKGROUND AND AIMS

The pathophysiology of acquired aplastic anemia (aAA) is most associated with T cell mediated immune dysfunction, but the role of CD4- CD8- double negative T cells (DNTs) in pediatric patients with aAA is unclear. In this study, we aimed to investigate the proportion of TCR-αβ+ DNTs in pediatric patients with aAA and correlation with the response to immunosuppressive therapy (IST).

MATERIALS AND METHODS

Assessment of DNTs from peripheral blood was done by sensitive multi-color flow cytometry. The potential clinical value of TCR-αβ+ DNTs was then assessed by the receiver operating characteristic (ROC) curves.

RESULTS

The retrospective study evaluated 164 pediatric patients with aAA and 105 healthy donors (HD). Our data showed higher proportion of TCR-αβ+ DNTs in total lymphocytes [1.04% (0.79%-1.40%) vs 0.69% (0.47%-0.87%), p < 0.001] and CD3+ T cells [1.52% (1.10%-1.96%) vs 1.10% (0.70%-1.40%), p < 0.001] in aAA compared to HD. Patients with SAA/VSAA achieving complete response (CR) after IST had a higher proportion of TCR-αβ+ DNTs at initial diagnosis, than those not achieving CR for total (1.21%±0.39 vs 0.78%±0.38, p < 0.05) and CD3+ T cells (1.74%±0.53 vs 1.15%±0.59, p < 0.05). The ROC analysis showed areas under the curves (AUCs) for TCR-αβ+ DNT proportion in lymphocytes and CD3+ T cells were 0.756 (cutoff value 1.33, p < 0.05) and 0.758 (cutoff value 1.38, p < 0.05), respectively. And the complete response rate was higher in TCR-αβ+ DNT proportion high group than in TCR-αβ+ DNT proportion low group at baseline (p < 0.001).

CONCLUSION

Our observations suggest that elevated TCR-αβ+ DNTs seems to play a role in the pathogenesis of aAA, and it was involve in immune response to IST.

An investigation of long-term outcome of rabbit anti-thymocyte globulin and cyclosporine therapy for pediatric severe aplastic anemia

Children with severe aplastic anemia (SAA) face heterogeneous prognoses after immunosuppressive therapy (IST). There are few models that can predict the long-term outcomes of IST for these patients. The objective of this paper is to develop a more effective prediction model for SAA prognosis based on clinical electronic medical records from 203 children with newly diagnosed SAA. In the early stage, a novel model for long-term outcomes of SAA patients with IST was developed using machine-learning techniques. Among the indicators related to long-term efficacy, white blood cell count, lymphocyte count, absolute reticulocyte count, lymphocyte ratio in bone-marrow smears, C-reactive protein, and the level of IL-6, IL-8 and vitamin B12 in the early stage are strongly correlated with long-term efficacy (P < .05). Taken together, we analyzed the long-term outcomes of rabbit anti-thymocyte globulin and cyclosporine therapy for children with SAA through machine-learning techniques, which may shorten the observation period of therapeutic effects and reduce treatment costs and time.

Impact of Conditioning Regimen and Graft-versus-Host Disease Prophylaxis on The Outcome of Haploidentical Peripheral Blood Stem Cell Transplantation for High-Risk Severe Aplastic Anemia in Children and Young Adults: A Report from the Pediatric Severe Aplastic Anemia Consortium of India

Allogenic hematopoietic cell transplantation (HCT) is the best curative approach for patients with severe aplastic anemia (SAA). The outcomes of HCT from haploidentical family donors (HFDs) have improved, making it a feasible option for patients lacking an HLA-identical donor. However, data on HFD-HCT for younger patients with SAA is sparse. In this multicenter retrospective study, we evaluated the outcomes of 79 patients undergoing HFD-HCT for SAA. All the patients were heavily pretransfused, the median time to HCT was >12 months, and 67% had failed previous therapies. Conditioning was based on fludarabine (Flu)-cyclophosphamide (Cy)-antithymocyte globulin (ATG)/total body irradiation (TBI) with or without thiotepa/melphalan (TT/Mel). Post-transplantation Cy (PTCy) and calcineurin inhibitors (CNIs)/sirolimus were used as graft-versus-host disease (GVHD) prophylaxis with or without abatacept. The rate of primary graft failure (PGF) was 16.43% overall, lower in patients conditioned with TT/Mel. The incidences of acute and chronic GVHD were 26.4% and 18.9%, respectively. At a median follow-up of 48 months, the overall survival (OS) and event-free survival (EFS) were 61.6% and 58.1%, respectively. Both OS and EFS were better in the TT/Mel recipients and with abatacept as GVHD prophylaxis. On multivariate analysis, the use of abatacept was found to favorably impact the outcome variables, including GVHD and EFS. Our study suggests that PTCy-based HFD-HCT is a reasonable option for young patients with high-risk SAA, in whom optimization of conditioning and GVHD prophylaxis might further improve outcomes.

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.

Cluster analysis of lymphocyte subset from peripheral blood in newly diagnosed idiopathic aplastic anaemia patients

INTRODUCTION

Idiopathic aplastic anaemia (IAA) is a heterogeneous autoimmune disease characterised by pancytopenia and bone marrow failure. The objective of the study was to investigate the clusters of lymphocyte subset in newly diagnosed IAA patients and explore their correlation with clinical characteristics.

METHODS

A total of 124 newly diagnosed IAA patients were enrolled. Lymphocyte subset was detected by flow cytometry. Cluster analysis was conducted to identify subgroups of patients based on lymphocyte subset.

RESULTS

Cluster analysis classified patients into four distinctive subgroups: Cluster 1 (CD4⁺ T cells dominant), Cluster 2 (CD8⁺ T cells dominant), Cluster 3 (NK cells dominant) and Cluster 4 (B cells dominant). Patients in Clusters 1 and 4 suffered more severe disease status than ones in Clusters 2 and 3 (p = .013). And with it, patients in Cluster 2 had the highest white blood cell count, haemoglobin level, reticulocyte count and reticulocyte percentage, while patients in Cluster 3 had the lowest lymphocyte percentage and the highest neutrophil count (all p < .05). Unexpectedly, patients in Cluster 3 tended to have superior curative effect than ones in other clusters, an ordinal logistic regression analysis further confirmed the independent correlation between Cluster 3 and good response to treatment. Lymphocyte subset clustering may serve as a biomarker for assessing disease severity and treatment efficacy in newly diagnosed IAA patients.Key MessagesNewly diagnosed IAA patients could be classified into 4 distinctive subgroups with similar immune patterns by using cluster analysis of lymphocyte subset.Clusters of lymphocyte subset were closely correlated with disease severity and treatment response of IAA.Lymphocyte subset clustering may serve as a promising tool for assessing disease severity and treatment efficacy in newly diagnosed IAA patients.

Aplastic anemia: a new complication in the recent mysterious hepatitis outbreak among children worldwide: two case reports

BACKGROUND

Recently, an unknown hepatitis outbreak among children has concerned many individuals worldwide. These cases are frequently reported, mainly from Europe and other countries. In this study, we present two similar patients, who, to the best of our knowledge, are the first cases reported in the Middle East (Shiraz, Fars Province, Iran). Unlike in similar cases reported up until 30 April 2022, our patients' hepatitis eventually resulted in aplastic anemia.

CASE PRESENTATION

In this study, we present cases of two Iranian boys aged 13 and 8 years with hepatitis of unknown origin who developed aplastic anemia in the course of hospitalization.

CONCLUSIONS

Hepatitis-associated aplastic anemia is a well-known immune-mediated form of aplastic anemia that we detected in our patients and treated with immunosuppressive therapy. One patient established a satisfactory response to the treatment, but unfortunately, the other was declared brain dead.

Cyclosporine Monotherapy in Pediatric Patients With Non-severe Aplastic Anemia: A Retrospective Analysis

Objective

The management of children with non-severe aplastic anemia (NSAA) is undefined and the efficacies and benefits of immunosuppressive therapy remain inconsistent. The study aimed to investigate the efficacy of Cyclosporine (CsA) monotherapy for pediatric NSAA.

Methods

Clinical data of children with NSAA who had been treated with CsA monotherapy at the outpatient department of Beijing Children's Hospital, Capital Medical University, National Children's Medical Center from January 2017 to March 2021 was collected retrospectively. Patients who had been treated <1 years until the end of follow-up were excluded. Transfusion-independent NSAA was further divided into moderate NSAA and mild NSAA according to the degree of cytopenia. Progression was defined as the development of transfusion-dependent AA or SAA and relapse was considered when treatment failed after initial response.

Results

A total of 95 pediatric patients with NSAA were enrolled in this study with 49 (51.6%) patients confirmed as mild NSAA, 38 (40%) as moderate NSAA and 8 (8.4%) as transfusion-dependent NSAA. The median treatment time of CsA was 22 (12–44) months. The overall response rate (ORR) was 57.9%, with 30.5% CR and 27.4% PR. Unexpectedly, patients with mild NSAA acquired lowest ORR (46.9%), then patients with moderate NSAA (63.2%), while 8 patients who were transfusion-dependent all had an active response to CsA. The granulocyte and megakaryocyte response was 46.9 and 55.8% respectively, while the erythrocyte response rate was as low as 22.5%. Univariate analyses revealed that patients with lower platelet count and higher interleukin 10 level predict an active response to CsA while higher level of fetal hemoglobin (HbF) tended to be a negative factor. Data of Treg cells before and after 1 year's treatment was available in a total number of 40 patients. Paired comparison found that the percentage of Treg cells in CD4+ T cells was decreased after 1 year's treatment of CsA (6.78 ± 2.72 vs. 5.23 ± 2.06, P = 0.001),both in responders and non-responders. The degree of decline in Treg cells between two distinctive response groups had no significant difference (P>0.05). With a median follow-up time of 22 months, 10.9% of responders relapsed and maintained NSAA while 27.5% of non-responders progressed to SAA or became transfusion-dependent. The overall progression rate was 11.6%.

Conclusion

CsA monotherapy had heterogeneous effects in the treatment of children NSAA Treatment approaches should be hierarchical and individual in clinical. Patients with lower platelet count and higher interleukin 10 level predicted an active response to CsA. While higher level of fetal hemoglobin (HbF) tended to be a negative factor. The percentage of Treg cells in CD4+ T cells was decreased broadly after treatment.

Efficacy and safety of immunosuppressive therapy with or without eltrombopag in pediatric patients with acquired aplastic anemia: A Chinese retrospective study

To determine the efficacy and safety of eltrombopag (E-PAG) combined with intensive immunosuppressive therapy (IST) for the treatment of pediatric patients with severe aplastic anemia (SAA). A total of 57 pediatric patients with newly diagnosed severe aplastic anemia were enrolled in this study. Thirty nine patients were treated with IST alone, consisting of porcine anti-human thymocyte globulin (30 mg/kg/day × 5 days) and cyclosporine A (CsA) (treated for 2 years, with a trough concentration maintained at 200-250 ng/mL), and 18 patients were treated with IST + E-PAG (12.5-50 mg/day, maintained for 6 months). We found no statistical difference between the response rates at 3 months for the two groups (CR: 12.8% vs. 22.2% p > 0.05, ORR: 56.4% vs. 77.7% p > 0.05). However, we found a statistical difference between the response rates at 6 months for the two groups (CR: 17.9% vs. 50% p < 0.05, ORR: 69.2% vs. 94.4% p < 0.05). The main side-effect during treatment with E-PAG was having a slightly to moderately elevated bilirubin level, which was temporary and controllable, accounting for approximately 66.6% (12/18) of patients in the IST + E-PAG group vs. 20.5% (8/39) of those in the IST group (p < 0.05). IST + E-PAG therapy appears to be more effective than IST alone for the treatment of pediatric SAA, with good tolerability and compliance. This approach deserves further exploration.

Efficacy and safety of eltrombopag in the first-line therapy of severe aplastic anemia in children

Eltrombopag is being investigated for the treatment of aplastic anemia (AA) by stimulating hematopoietic stem cell (HSC) proliferation. To evaluate the efficacy and safety of eltrombopag in the first-line therapy of pediatric AA. The present retrospective study assessed pediatric patients with newly diagnosed AA administered immunosuppressive therapy (IST) (rabbit ATG combined with CSA) with eltrombopag at a single center from March to September 2017. All patients were followed up for >2 years. A total of 14 patients (8 males), averagely aged 86 months, were enrolled in this study. Eltrombopag was administered with a median time to initiation of 19.5 days after IST; the median course of treatment was 253 days. Complete and overall response rates at 6 months were 64.3% (9/14 case) and 78.6% (11/14 cases), respectively. The survival rate was 100%, and no relapse occurred in responders. Eltrombopag was well-tolerated; however, the most common adverse events included indirect bilirubin elevation, jaundice, and transient liver-enzyme elevation. By the end of follow-up, bone marrow chromosomes were normal, and no abnormal myelodysplastic syndrome (MDS)-related clones appeared. Addition of eltrombopag to IST is associated with markedly increased complete response with respect to hematology in pediatric patients with SAA compared with a historical cohort, without intolerable side effects.

Clinical Outcome of Acquired Post-Immunosuppressive-Therapy Aplastic Anemia in Pediatric Patients: A 13-Year Experience in Two Southern China Tertiary Care Centers

Objective

The aim of the present study is to evaluate the efficacy, complications, and contributing factors of immunosuppressive therapy (IST) response in children with acquired aplastic anemia (AA) and to explore optimal therapeutic methods for different clinical AA types.

Methods

A total of 130 children diagnosed with acquired AA underwent IST in the Department of Pediatrics at Sun Yat-sen Memorial Hospital and the Department of Pediatrics at Seventh Affiliated Hospital, Sun Yat-sen University, between January 1, 2006, and July 15, 2020. The overall survival (OS), response rates, complications, and response predictors were analyzed. The response rates were compared according to clinical AA type.

Results

All 130 children with AA were followed up with for a median of 50.6 months. Among the patients, 25 had non-severe AA (NSAA), 64 had severe AA (SAA), and 41 had very severe AA (VSAA). All patients initially received IST. In 13 patients, the IST failed; these patients received an allo-hematopoietic stem cell transplant as a salvage regimen. The OS rate was 90.3% ± 2.8%, and the response rates at 3, 6, 9, and 12 months were 34.19%, 39.32%, 49.57%, and 66.67%, respectively. The prolonged follow-up period might have led to higher response rates, especially in patients with SAA and VSAA. A multivariate logistic regression analysis of prognostic factors was conducted; the results showed that high red blood cell (RBC) and platelet (PLT) counts were associated with a high overall response rate and that the RBC count at diagnosis is a major contributing factor.

Conclusion

With the use of rabbit anti-thymocyte globulin, proper cyclosporine management, and a prolonged IST follow-up period, a higher number of patients with acquired AA than normal achieved response. Proportionally, the number of patients who achieved remission within 12 months was higher in the SAA group (38.18%→63.64%) and VSAA group (28.95%→65.79%) than in the NSAA group (58.33%→75%). Higher RBC and PLT counts at diagnosis can predict a favorable outcome.

Relationship between plasma rabbit anti-thymocyte globulin concentration and immunosuppressive therapy response in patients with severe aplastic anemia

OBJECTIVES

Patients with acquired aplastic anemia (AA) without HLA-matched sibling donors or aged >40 years receive immunosuppressive therapy (IST) with anti-thymocyte globulin (ATG). We investigated the relationship between plasma rabbit ATG (r-ATG) concentration and IST response.

METHODS

From May 2012 to October 2017, 81 patients with severe AA who required initial IST were included. A 1:1 block randomization was employed for 2.5 and 3.5 mg/kg doses of r-ATG.

RESULTS

No significant difference in response rates was observed between the 2.5 and 3.5 mg/kg groups (63% vs. 58%, P = .894). Median r-ATG concentrations on days 14 and 28 after IST were 15.2 (0.0-97.7) and 1.8 (0.0-74.9 µg/mL), respectively. According to r-ATG concentration, response rates were significantly higher in the group with higher r-ATG concentration than in those with lower r-ATG concentration (day 14, 88% vs. 52%; P = .006 and day 28, 79% vs. 46%; P = .005). In multivariate analysis, higher r-ATG concentrations at day 28 were independent predictors of favorable response to IST at 6 months (odds ratio, 0.29; 95% confidence interval, 0.09-0.93; P = .037).

CONCLUSIONS

The present data indicate that higher r-ATG concentration at day 28 resulted in improved IST response.

Eltrombopag in Combination with Rabbit Anti-thymocyte Globulin/Cyclosporine A in Immunosuppressive Therapy-naïve Patients with Aplastic Anemia in Japan

Objective In Japan, immunosuppressive therapy (IST) with anti-thymocyte globulin (ATG), and cyclosporine A (CsA) is the standard of care in patients with aplastic anemia (AA) who are not indicated for stem-cell transplantation, although some patients may experience relapse. This study assessed the efficacy and safety of eltrombopag in combination with rabbit-ATG/CsA in IST-naïve patients with non-severe or severe AA in Japan. Methods In this non-randomized, open-label, single-arm, phase II study, rabbit-ATG/CsA and eltrombopag were initiated on Days 1 and 15 (±3 days), respectively, and continued for ≥26 weeks; rabbit-ATG was given for 5 days (Days 1 to 5). The primary endpoint was the overall response rate (ORR) at Week 26. Patients Patients with AA who were IST-naïve and ≤70 years old or between 71 and 75 years old based on the recommendation of the investigator were enrolled in Japan. Results Of the 11 enrolled patients, 10 started treatment with eltrombopag. The ORRs at Weeks 26 and 52 were 70.0% and 60.0%, respectively. The ORR at Week 26 was 100% (all 3 patients) in patients with non-severe AA and 57.1% (4/7) in patients with severe AA. Among transfusion-dependent patients, 66.7% (4/6) and 62.5% (5/8) became red blood cell- and platelet-transfusion independent, respectively. The most common adverse events were nausea and headache. No deaths or hematologic malignancies were reported. A cytogenetic abnormality was reported in one patient. Conclusion This study confirmed the clinical benefit of eltrombopag plus rabbit-ATG/CsA in IST-naïve patients with non-severe or severe AA in Japan.

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.

Severe aplastic anaemia in children: Impact of histopathology profile and treatment on very long-term outcomes

AIM

To assess very long-term outcomes of children with severe aplastic anaemia (SAA) and impact of histopathology and of different treatments over time.

METHODS

We conducted a retrospective study of 57 consecutive patients with SAA during 1973-2019. According to period, treatment consisted of androgens, immunosuppressive treatment (IST) and haematopoietic cell transplantation (HCT) in 14, 31 and 13 patients, respectively. Histopathology immune profiles were studied on bone marrow (BM).

RESULTS

Response rate (RR) to androgens was 35%, with long-term survivorship in 4 of 5 responders. RR and 10-year overall survival (OS) after IST was 65% and 80%, respectively. RR was higher in girls (92% vs 43% in boys, P = .02). Mean baseline BM values of CD34 + and of B-lymphocytes in responders vs non-responders were 1.3% vs 0 (P = .08) and 14.1% vs 9.7% (P = .07), respectively. After IST, BM cellularity gradually increased and cytotoxic T-lymphocytes decreased (time variation P = .003 and 0.07, respectively). Outcome did not differ between patients with IST or frontline HCT. Ten-year OS improved over time, increasing from 35.3% to 77.1% and 77% during 1973-1985, 1986-2003 and 2004-2019, respectively.

CONCLUSION

Histopathology may refine response prediction to IST. The course of SAA in children, a previously fatal disease, was altered in recent times.

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.

Hepatitis-associated aplastic anemia in pediatric patients: single center experience

INTRODUCTION

Hepatitis-associated aplastic anemia is a rare type of acquired aplastic anemia that occurs after hepatitis. This study investigated cases with hepatitis-associated aplastic anemia.

METHODS

The files of patients with hepatitis-associated aplastic anemia who were followed up in our hospital between 2011-2019 were reviewed retrospectively.

RESULTS

A total of 15 patients with hepatitis-associated aplastic anemia (10 males, 5 girls; mean age 10.26 ± 3.61 years) were analyzed. The mean duration between hepatitis and aplastic anemia was 5.06 ± 4.19 months. The majority of patients had mild hepatitis. The causes of hepatitis were detected only in six patients: three had hepatitis B, one had hepatitis A, one had autoimmune hepatitis and, one had a hydatid cyst. The cause of hepatitis was not found in nine patients. Only one patient with hepatitis-associated aplastic anemia developed spontaneous remission, and the others required immunosuppressive therapy and/or hematopoietic stem cell transplantation. Only one patient died because of sepsis. The other patients are still under follow-up and treatment.

CONCLUSION

Patients with hepatitis-associated aplastic anemia, mostly of unknown cause, can be successfully treated with immunosuppressive therapy and/or hematopoietic stem cell transplantation.

Efficacy and safety of porcine ALG compared to rabbit ATG as first-line treatment for children with acquired aplastic anemia

OBJECTIVE

To assess the outcomes of children with acquired aplastic anemia (AA) treated in China with first-line porcine anti-lymphocyte immunoglobulin (p-ALG)/rabbit anti-thymocyte immunoglobulin (r-ATG) combined with cyclosporine A (CSA).

METHODS

We performed a single-center, non-randomized, retrospective cohort study to assess the outcomes of 189 children with AA treated in China with first-line p-ALG/r-ATG combined with CSA between 2014 and 2018.

RESULTS

No significant differences were observed in the overall response rates at 3, 6, 12, or 24 months (3 months: 61.9% vs 67.4%, P = .5; 6 months: 70.9% vs 73.9%, P = .69; 12 months: 77.3% vs 73.3%, P = .58; 24 months: 81.6% vs 78.6%, P = .59) after either p-ALG- or r-ATG-based immunosuppressive therapy. No significant differences were observed in overall survival or failure-free survival between the p-ALG group and the r-ATG group.

CONCLUSION

Our results reveal that the therapeutic efficacy and safety of p-ALG combined with CSA did not differ significantly from those of r-ATG combined with CSA as first-line therapy for pediatric patients with AA. Moreover, p-ALG has the advantage of significantly lower cost compared with r-ATG.

Cord blood infusion-accelerated hematopoietic recovery after combined immunosuppressive therapy with fludarabine and rabbit ATG in severe aplastic anemia

Immunosuppressive therapy (IST) with anti-thymocyte globulin (ATG) and cyclosporine A (CsA) is currently the standard treatment for patients with severe aplastic anemia (SAA) who have no suitable donor or are ineligible for allogeneic stem cell transplantation. However, the delayed hematopoietic recovery, which accounts for most early deaths, remains a key problem. Thus, we designed an IST protocol with fludarabine, rabbit ATG, and CsA followed by unrelated cord blood (UCB) infusion to study whether hematopoiesis could be accelerated. Nineteen patients were enrolled in this study. The median neutrophil recovery time was 22 days and the treatment-related mortality within 3 months was 5.3%. The median platelet recovery time was 180 days. Six patients had transient or sustained UCB engraftment and the median platelet recovery time of these patients was significantly shorter than those who had no UCB engraftment (46 days vs 206 days, p = 0.006). The cumulative incidence of response rate at 12 months was up to 88.7% with CR rate of 72.2%. The overall survival at 2 years and 5 years was 94.7% and 78.9%, respectively. These results suggest that UCB infusion may play an important role in accelerating hematopoietic recovery in this protocol.

Reactivation and dynamics of cytomegalovirus and Epstein-Barr virus after rabbit antithymocyte globulin and cyclosporine for aplastic anemia

OBJECTIVES

This study aimed to identify the natural course of cytomegalovirus (CMV)/Epstein-Barr virus (EBV) after rabbit antithymocyte globulin and cyclosporine (rATG-CsA) for aplastic anemia (AA).

METHODS

In 113 prospectively observed AA patients treated with rATG-CsA, the CMV/EBV cohort was classified into two groups by baseline viremic status: no viremia (CMV-G1, n = 112; EBV-G1, n = 98) and the presence of viremia (CMV-G2, n = 1; EBV-G2, n = 13).

RESULTS

In CMV-G1, the mean CMV load increased up to 3 months but was completely resolved from 6 months. The mean EBV load of EBV-G1 showed a peak at 1 month and then gradually decreased over time but remained detectable throughout the observation period. EBV-G2 showed fluctuating EBV dynamics. With reactivation rates of 38.4% in CMV-G1 and 62.2% in EBV-G1, a longer time to rATG-CsA from diagnosis and a lower absolute lymphocyte count at 1 month from rATG-CsA were significantly associated with CMV and EBV reactivation, respectively. The mean peak CMV and EBV loads of patients with CMV-related (3.5%) and EBV-related (0.9%) diseases were evidently higher than those of the remaining patients without CMV and EBV diseases in the respective cohort.

CONCLUSION

Considering frequent reactivation and distinct courses of CMV/EBV, virologic surveillance is recommended after rATG-CsA for AA.

[A clinical study of haploidentical hematopoietic stem cell transplantation in the treatment of pediatric patients with acquired severe aplastic anemia: single center experience]

目的

探讨单倍型造血干细胞移植（haplo-HSCT）治疗儿童获得性重型再生障碍性贫血（SAA）的疗效。

方法

回顾性分析2011年12月1日至2017年12月1日接受haplo-HSCT的59例SAA患者。

结果

①全部59例SAA患儿中男37例、女22例，中位年龄4.5（1.2~14.8）岁，中位体重43（12~80）kg；SAA-Ⅰ型47例，SAA-Ⅱ型12例，26例为极重型再生障碍性贫血（VSAA）；首次移植56例，二次移植3例。②预处理选用白消安+环磷酰胺+抗胸腺细胞球蛋白（ATG）方案或白消安+氟达拉滨+环磷酰胺+ATG方案；采用环孢素A（CsA）+霉酚酸酯+甲氨蝶呤方案预防急性GVHD；回输单个核细胞中位数为15.60（7.74~21.04）×10⁸/kg，CD34⁺细胞中位数为4.86（3.74~7.14）×10⁶/kg。③全部59例患儿均获得中性粒细胞和血小板植入。中性粒细胞植入中位时间为13（10~19）d，血小板植入中位时间为19（9~62）d。④Ⅰ~Ⅱ、Ⅲ/Ⅳ度急性GVHD发生率分别为45.76%（27/59）、13.56%（8/59），慢性GVHD发生率为8.47%（5/59）。巨细胞病毒血症发生率为59.32%（35/59）、EB病毒血症发生率为28.81%（17/59）。⑤中位随访时间30（8~80）个月，57例无病存活，2例死亡（均死于GVHD），5年总生存率、无失败生存率均为（96.4±2.5）%。

结论

haplo-HSCT是儿童SAA疗效较好的治疗方法。

Immunosuppressive therapy (IST) in adult patients with acquired aplastic anemia (AA): A single-center experience over the past 15 years

OBJECTIVE

Immunosuppressive therapy (IST) with horse anti-thymocyte globulin (hATG) and cyclosporine (CsA) is considered one of the first-line therapies in patients (pts) with acquired aplastic anemia (AA).

METHODS

In our single-center, retrospective analysis response rates (RRs) to ATG/CsA at a minimum of 6 mo were evaluated in 67 treatment-naïve (TN) AA pts (52.2% (35/67) females; median age 45 y (range 18-89 y)) being treated at the West German Cancer Center at the Department of Hematology at the University Hospital of Essen between April 2000 and December 2015.

RESULTS

Overall 6 mo RRs in TN pts following ATG/CsA were 67.2% (45/67) (5-year OS: 79.5%). In TN hATG-treated pts 6 mo RRs were 75.5% (37/49) (5-year OS: 81%) compared to 44.4% (8/18) (5-year OS 73.5%) following rabbit ATG (rATG). Response to ATG/CsA was dependent of age, absolute reticulocyte count (ARC), and disease severity. Six mo RRs to salvage ATG/CsA in relapsed/refractory (R/R) pts were 37.5% (6/16).

CONCLUSION

Our data independently confirm the findings of previous studies that hATG/CsA is superior to rATG/CsA in TN pts. The lack of hATG availability should not result in abstaining it from an indicated ATG therapy, even though ATGAM^® is not registered in Germany.

Comparable Outcome with a Faster Engraftment of Optimized Haploidentical Hematopoietic Stem Cell Transplantation Compared with Transplantations from Other Donor Types in Pediatric Acquired Aplastic Anemia

Haploidentical family donors have been used as an alternative source in hematopoietic cell transplantation for patients with severe aplastic anemia. We evaluated and compared the outcomes of transplantation in pediatric acquired severe aplastic anemia based on donor type. Sixty-seven patients who underwent transplantation between 1998 and 2017 were included. Fourteen patients received grafts from matched sibling donors, 21 from suitable unrelated donors, and 32 from haploidentical family donors. Ex vivo CD3⁺ or αβ⁺ T cell-depleted grafts were used for haploidentical transplantation. Sixty-five patients (97.0%) achieved neutrophil engraftment at a median of 11 days. Haploidentical transplantation resulted in significantly faster neutrophil engraftment at a median of 10 days, compared with 14 days in cases of matched sibling donors and 12 days in cases of unrelated donor recipients. Nine patients experienced graft failure, and 5 of 7 who underwent a second transplantation are alive. There was no difference in the incidence of acute or chronic graft-versus-host disease based on donor type. The 5-year overall survival and failure-free survival rates were 93.8% ± 3.0% and 83.3% ± 4.6%, respectively, and there was no significant survival difference based on donor type. The survival outcomes of haploidentical transplantation in patients were comparable with those of matched sibling or unrelated donor transplantation. Optimized haploidentical transplantation using selective T cell depletion and conditioning regimens including low-dose total body irradiation for enhancing engraftment may be a realistic therapeutic option for pediatric patients with severe aplastic anemia.

Immunosuppressive therapy for aplastic anemia: a single-center experience from western India

Immunosuppressive therapy (IST) with antithymocyte globulin (ATG) and cyclosporine A (CsA) is the first-line therapy for acquired aplastic anemia (AA) in those not suitable for bone marrow transplant. Horse ATG (hATG) is preferred for this purpose, but its use is often impeded by shortages and costs. Being a rare disease, there is limited data on this therapy. This study aimed to evaluate this therapy in a large cohort of AA patients from western India. We retrospectively analyzed AA patients who received an indigenous preparation of hATG along with CsA as first-line treatment, between 2012 and 2015, at our center and evaluated the response, survival, and occurrence of adverse events. The response was further assessed separately for adults and children. During the period, 91 AA patients (4 non-severe, 57 severe and 30 very severe) were treated with IST. At 2 years, 23.5% adults and 39.1% children showed complete response and an overall of 68.1% cases became transfusion independent. More than half of the patients developed febrile neutropenia while roughly one sixth of the patients developed gum hypertrophy and/or hypertension. Two patients had clonal evolution. Mortality rate was calculated to be 31%; most common causes of death were infection and intracranial hemorrhage. The results of the study substantiate the effectiveness of IST in AA, using an inexpensive indigenous preparation of hATG along with CsA.

Rabbit antithymocyte globulin dose does not affect response or survival as first-line therapy for acquired aplastic anemia: a multicenter retrospective study

In a prospective randomized study, treatment for aplastic anemia (AA) with rabbit antithymocyte globulin (r-ATG) and cyclosporine showed inferior hematological response and survival in comparison to horse antithymocyte globulin (h-ATG) and cyclosporine. However, h-ATG was discontinued in most Asian, South American, and European countries, where r-ATG became the only ATG formulation available. We retrospectively evaluated consecutive patients with acquired AA who received either rabbit (n = 170) or horse (n = 85) ATG and cyclosporine for first-line treatment from 1992 to 2014 in seven referral centers in Brazil and Argentina. Overall response at 3 months was 17% (95%CI, 11-23%) for r-ATG and 44% (95%CI, 33-55%) for h-ATG (p < 0.001). At 6 months, it was 31% (95%CI, 34-39%) for r-ATG and 59% (95%CI, 48-69%) for h-ATG (p < 0.001). Overall survival at 5 years was 57% (95%CI, 47-65%) for r-ATG and 80% (95%CI, 69-87%) for h-ATG (log-rank = 0.001). Relapse was significantly higher in patients receiving h-ATG (28%; 95%CI, 17-43%) as compared to r-ATG (9.4%; 95%CI, 4-21%; log-rank, p = 0.01). The type of ATG was the only factor associated with both response and survival. The r-ATG dose varied from 1 to 5 mg/kg/day, but it did not correlate with outcomes. In summary, this is the largest multicenter study comparing the two ATG formulations in AA. Our results indicate that the dose of r-ATG does not influence hematologic response or survival in first-line therapy for acquired AA. Considering the toxicity and costs of r-ATG, our findings challenge its aggregate benefit to cyclosporine therapy and further strengthen that h-ATG should remain standard therapy in AA.

Updated Guidelines for the Treatment of Acquired Aplastic Anemia in Children

PURPOSE OF REVIEW

This review aimed to provide updated guidelines for the management of children with acquired aplastic anemia (AA), particularly focusing on hematopoietic stem cell transplantation (HSCT).

RECENT FINDINGS

Failure-free survival for children with aplastic anemia has been shown to be better after bone marrow transplantation (BMT) from matched or one-locus mismatched related donors (MRD/1MMRD) than after immunosuppressive therapy (IST). A combination of the absence of minor paroxysmal nocturnal hemoglobinuria clones and short telomere length was identified as a strong predictor of a poor response to IST. Upfront HSCT from matched unrelated donors (MUD) and MRD was recently demonstrated to have comparable outcomes. Moreover, unrelated cord blood transplantation (UCBT) and haploidentical HSCT have shown promising outcomes, and the fludarabine/melphalan-based regimen has resulted in excellent survival without poor graft function. BMT from MRD/1MMRD is the treatment of choice. When a MRD/1MMRD is not available, upfront BMT from a MUD should be considered for patients with only a slim chance of responding to IST. UCBT and haploidentical HSCT are promising options. This updated treatment algorithm should improve overall outcomes for children with AA.

Acquired Aplastic Anemia: What Have We Learned and What Is in the Horizon?

Acquired aplastic anemia (aAA) characterized by peripheral pancytopenia and bone marrow aplasia is a rare and serious disorder. Differential diagnosis includes constitutional bone marrow failure syndromes and myelodysplastic disorders. Autoimmune reaction to altered hematopoietic stem cells highlights the underlying mechanism. Matched related donor allogeneic hematopoietic stem cell transplantation is the ideal pediatric treatment; alternative approaches include immunosuppressive therapy and use of eltrombopag. Progression to clonal disorders can occur. Recently, alternative donor hematopoietic stem cell transplantation outcomes have significantly improved. Despite advances, aAA continues to be a challenge for hematologists.

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.

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.

Anti-thymocyte serum as part of an immunosuppressive regimen in treating haematological immune-mediated diseases in dogs

OBJECTIVES

To report the outcomes associated with the use of rabbit anti-dog thymocyte serum in dogs with haematological immune-mediated diseases.

METHODS

Medical records from 2000 to 2016 of patients diagnosed with immune-mediated haemolytic anaemia, immune-mediated thrombocytopenia, pancytopenia and myelofibrosis were reviewed. All dogs had a severe or refractory disease and received rabbit anti-dog thymocyte serum. Lymphocyte counts were used to monitor the immediate anti-thymocyte effect of therapy; long-term patient outcome was recorded.

RESULTS

A total of 10 dogs were included. All dogs except one had a notable decrease in their lymphocyte count after rabbit anti-dog thymocyte serum; four of nine had a decrease to less than 10% of the initial lymphocyte count and one dog reached 10·8%. All dogs were discharged from the hospital following their treatment. The dog with no alteration of lymphocyte count following therapy with rabbit anti-dog thymocyte serum had refractory immune mediated haemolytic anemia and was euthanised within two weeks. All other cases achieved clinical remission with immunosuppressive therapy eventually being tapered (3 of 10) or discontinued (6 of 10).

CLINICAL SIGNIFICANCE

Rabbit anti-dog thymocyte serum therapy might be of interest as an adjunctive therapy in refractory immune-mediated diseases and suppressed lymphocyte counts in most dogs.

Post-therapeutic recovery of serum interleukin-35 level might predict positive response to immunosuppressive therapy in pediatric aplastic anemia

BACKGROUND

The predictive value of interleukin-35 (IL-35) on efficacy of immunosuppressive therapy (IST) in aplastic anemia (AA) has not been well investigated. The aim of the study was to evaluate the association between serum IL-35 level and response to IST in pediatric AA.

METHODS

A total of 154 children with AA and 154 controls were included between January 2012 and December 2013. Blood and bone marrow fluid specimens were collected. Serum level of IL-35 was determined by enzyme-linked immunosorbent assay. Patients were treated with IST, and response to therapy was evaluated during 180-day follow-up period after starting therapy.

RESULTS

Serum levels of IL-35 at admission decreased significantly in patients compared with that in controls (10.9 ± 5.5 pg ml^-1 and 45.3 ± 8.8 pg ml^-1, p < 0.001). After starting IST, serum levels of IL-35 in patients recovered 30.7 ± 9.7 pg ml^-1 in the first 28 days (p < 0.001). During the follow-up period, increased range of serum IL-35 level ≥30.7 pg ml^-1 in the first 28 days was associated with effective response to therapy (odds ratio 7.97, 95% confidence interval 3.82-16.79). In addition, Fas/FasL protein expression in bone marrow mononuclear cells dropped significantly in the same group of patients in the first 28 days (p < 0.05).

CONCLUSION

The study revealed that post-therapeutic recovery of circulating IL-35 concentration might be an independent predictor for effective response to IST in pediatric AA. Moreover, apoptosis might be involved in such a forecasting process.

How I treat acquired aplastic anemia

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

Haploidentical transplantation for pediatric patients with acquired severe aplastic anemia

Techniques for haploidentical hematopoietic stem cell transplantation (haplo-HSCT) to treat severe aplastic anemia (SAA) have recently improved, but no protocol has been evaluated in a large number of pediatric patients. Fifty-two children with SAA received haplo-HSCT in our center. The treatment protocol used G-CSF-primed bone marrow with G-CSF-mobilized PBSCs without in vitro T-cell depletion. The conditioning regimen included busulfan/cyclophosphamide and antithymocyte globulin. Fifty-one patients achieved primary engraftment; one child died of regimen-related toxicity on the day +1. Secondary graft failure occurred in three patients. The cumulative incidences of aGVHD grade II-IV and grade III-IV were 39.2±0.5 and 13.7±0.2%, respectively. The cumulative incidence of cGVHD was 34.2±0.5%. The 3-year overall and failure-free survival rates were 84.5±5.0 and 82.7±5.2%, respectively, with a median follow-up time of 744.5 days (100-3294) for surviving patients. The Eastern Cooperative Oncology Group score was the only predictor of overall and failure-free survival rates. Clinical outcomes were similar between the upfront and salvage group. This result suggests that both newly diagnosed and refractory pediatric SAA patients benefit from haplo-HSCT, especially when patients are in good general condition. Therefore, haplo-HSCT might be an alternative therapy for pediatric SAA patients without HLA-matched sibling donors.

Efficacy of rabbit antithymocyte globulin as first-line treatment of severe aplastic anemia: an Asian multicenter retrospective study

Due to the unavailability of horse antithymocyte globulin (ATG) in many markets worldwide, patients with severe aplastic anemia (SAA) are limited to the use of rabbit ATG. We aimed to analyze hematologic response and overall survival (OS) of Asian patients treated with rabbit ATG as first-line therapy of SAA. We retrospectively reviewed the medical records of 97 consecutive patients who received rabbit ATG as first-line treatment of SAA from 2006 to 2012 at centers in four Asian countries. The primary endpoint was 6- and 12-month overall response rates (ORR) for patients receiving rabbit ATG within the recommended dose range (2.5-3.75 mg/kg/day). Secondary endpoints included ORR in patients receiving any dose of rabbit ATG and 2-year OS. For patients who received rabbit ATG within the recommended dose range, 6- and 12-month ORRs were 17.4 and 63.6 %, respectively. For patients who received any dose of rabbit ATG, 6- and 12-month ORRs were 24.3 and 68.6 %, respectively. The 2-year OS rate was 86.3 %. Rabbit ATG is effective for treatment of SAA in Asian patients. The 12-month ORR and 2-year OS with rabbit ATG were comparable to historical results obtained with horse ATG.