Therapy For Severe Aplastic Anemia Research Articles

Efficacy and Safety of Avatrombopag in Combination with Standard Immunosuppressive Therapy for Severe Aplastic Anemia

Severe aplastic anemia (SAA) is a life-threatening bone marrow failure disease. The addition of eltrombopag to immunosuppressive therapy (IST) improves the response rate and response quality of SAAs, but its hepatotoxicity is concerning. Avatrombopag (AVA), another small-molecule thrombopoietin receptor agonist without hepatotoxicity, has unknown efficacy in SAA treatment. This retrospective study aimed to assess the efficacy and safety of AVA, a small-molecule thrombopoietin receptor agonist, when added to IST in SAA patients. A total of 42 patients treated with IST and AVA were compared to a historical cohort of 84 patients receiving IST alone, utilizing propensity score matching. The median age was 31.5 (6.0-67.0) years old in Group A and 26 (16.0-45.0) years old in Group B. At 3 months, Group A showed higher complete response (CR) and overall response (OR) rates than Group B (CR: 19.0% vs. 4.8%, P = 0.024; OR: 54.8% vs. 39.3%, P=0.145). Higher CR and OR rates were also found at 6 months in Group A than in Group B (CR 31.0% vs. 14.3%, P=0.145; OR 71.4% vs. 51.2%, P=0.048). In multivariate analysis of Group A, a shorter interval from disease onset to anti-thymocyte globulin (ATG) treatment (≤6 months) (P=0.005) predicted better responses rate at 6 months. Event free survival was also improved in Group A (60.7% vs. 49.6%). AVA was well-tolerated, with no hepatic injury observed during treatment, even in those with pre-existing hepatic impairment. The addition of AVA to IST improves both the response rate and response quality in SAA patients while ensuring safety.

Study of the relationship between thyroid autoimmunity, obesity and serum leptin level in a sample of Egyptian individuals

Obesity is a worldwide health problem, and its prevalence is increasing steadily all over the globe. Leptin, mainly produced by adipocytes, was identified to modulate the immune system, as well as contributing to increased production of thyroid peroxidase antibodies (TPO-Ab) and thyroglobulin antibody (TG-Ab). Autoimmune thyroiditis, mainly Hashimoto's thyroiditis, is believed to be the main cause of hypothyroidism in iodine sufficient regions, (TPO-Ab) and (TG-Ab) are the hallmarks of this disease. This study aimed to assess the relationship between thyroid autoimmunity, obesity and serum leptin level in a sample of Egyptian individuals. This study was a case control study which included 60 participants, recruited from the outpatient of the Internal Medicine Clinic at Ain Shams University Hospitals, during the period from February 2022 to October 2022. They were divided into two groups: Group 1 included 30 participants, have Residual hematopoiesis is an important prognostic factor of immunosuppressive therapy in severe aplastic anemia (BMI) >30 kg/m2, and Group 2 included 30 participants, have BMI (18.5-25 kg/m2). We detected serum leptin, thyroid profile and thyroid antibodies using the enzyme linked immunosorbent assay and other immunoassays. Serum levels of leptin, thyroid-stimulating hormone (TSH) and glycated hemoglobin (HbA1c) were statistically significantly higher in group 1 than in group 2 (p=0.0001 for all). Also, there was a statistically significant positive correlation between leptin level and Anti-TPO in group 1 (p=0.002). In addition, in group 1, there was a statistically significant positive correlation between serum leptin level and TSH (p=0.0001). In conclusion, there is a relationship between thyroid autoimmunity and serum leptin level in obese subjects.

Predictive value of T cell receptor repertoire profiling for immunosuppressive therapy in severe aplastic anemia

Predictive value of T cell receptor repertoire profiling for immunosuppressive therapy in severe aplastic anemia

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.

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

Efficacy of Oxymetholone in Severe and Nonsevere Acquired Aplastic Anemia: A Propensity Score Matching Analysis.

Bone marrow transplantation, antithymocyte globulin/cyclosporine and eltrombopag are recommended as first-line therapy of severe aplastic anemia (SAA). However, androgens could be considered as front-line treatment among any patients ineligible for better methods although unsatisfactory efficacy is presented. This retrospective study aimed to evaluate response and survival rate of practical-based treatment with oxymetholone. This constituted an analysis of patients receiving a diagnosis of acquired aplastic anemia (AA) at the age of 15 or over and receiving oxymetholone between January 2004 and December 2018. Propensity Score Analysis (PSA) 1:1 matching was performed, according to sex, age and interval from first symptom to treatment. The primary outcome was one-year overall response (OR). Seventy-four patients were successfully matched by PSA. The 1-year OR of oxymetholone in the nonsevere AA (nSAA) and SAA/very severe AA (vSAA) groups was 54.1 and 13.5%, respectively (P <0.001). With median follow-up 2.7 years, the overall survival was 59.5% in nSAA and 37.8% in SAA/vSAA (P = 0.051). Median survival in nSAA and SAA/vSAA were 7.0 years and 1.8 years, respectively (P = 0.045). However, the responders of SAA/vSAA had longer survival than nonresponders of the nSAA group. These results revealed longer survival among the responders of patients with AA, even in the SAA/vSAA group. However, close monitoring of therapeutic responses is still performed. Switching therapy is necessary when remission is undetected after 6 months of oxymetholone treatment.

Anti-Human 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

Immunosuppressive therapy (IST) based on antithymoglobin (ATG) and cyclosporin (CsA) is the first-line treatment for severe aplastic anemia (SAA) patients who are ineligible for transplantation. Horse ATG is recommended as the standard preparation for first-line immune suppression in SAA, but it has been unavailable in China since the year 2000. The anti-human T lymphocyte porcine immunoglobulin (p-ATG, provided by Yujin Bio-Pharma Wuhan CNBG Co., Ltd., Wuhan, China) was made available in 1983 and approved for the treatment of aplastic anemia by the Sino Food and Drug Administration in 2004. It is a commonly used ATG preparation in IST for SAA in China since 2009. To date, only a few small retrospective cohort studies reported that p-ATG combined with cyclosporine (CsA) is a useful immunosuppressive regimen for SAA in China. This study retrospectively analyzed the data of 1023 consecutive patients diagnosed with SAA that aimed to evaluate the early hematologic response and long-term outcomes of this large cohort of patients with SAA who received p-ATG plus CsA as first-line therapy from 2010 to 2019. Patients received p-ATG for 5 consecutive days (day 1-5), at a dose of 20 mg/kg/day. And CsA was administered orally from day 1 of p-ATG treatment at two separate doses starting from 3 to 5 mg/kg/day and adjusted to maintain the trough concentration at 150-250 ng/ml and the peak concentration at 800-1000 ng/ml. One thousand twenty-three aplastic anemia were included in this study, with a median age of 24 (4-75) years, with 500 males and 473 females. The median follow-up was 57.2 months (3 days-137.5 months). Twenty-nine patients died within 3 months after IST, with an early death rate of 2.8% (29/1023); the median death time was 0.9 (0.1-2.9) months. The overall hematologic response rate (ORR) was 40.6% (415/1023) at 3 months, including 5.9% (60/1023) of patients with CR. The ORR was 53.2% (544/1023) at 6 months, including 13.5% with CR. Of the 395 patients who did not respond at 6 months, 26.1% (103/395) had an overall response at 12 months without any rescue treatment (10 had a CR, 93 had a PR). By the last follow-up, 9.2% (64/697) of the patients had experienced a relapse. The 5-year cumulative incidence of relapse was 9.0% [95% confidence interval (CI), 4.2 to 16.0%]. The 5-year cumulative incidence of clonal evolution was 4.5% (95% CI, 1.4 to 10.6%). The 5-year cumulative incidence of hPNH was 4.7% (95% CI, 1.2 to 12.4%). In patients with PNH clones at diagnosis, the 5-year cumulative incidence of hPNH was 22.5% (95% CI, 10.1 to 37.8%). The 5-year OS rate was 83.7% (95% CI, 81.1 to 86.0%). The 5-year event-free survival rate was 50.4% (95% CI, 47.1 to 53.5%). In 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 where h-ATG is not available.

Granulocyte Transfusions As an Adjunctive Therapy in Severe Aplastic Anemia

Patients with severe aplastic anemia (SAA) are at high risk for infections due to prolonged neutropenia. Results of a historic multicenter randomized control trial of granulocyte transfusions (GTs) in patients with severe neutropenia failed to demonstrate significant differences in the composite outcome of overall survival (OS) and microbial response but was limited by patient accrual and variable and often low granulocyte collections and dosing. In the current study, we aimed to characterize the role of GTs in SAA as they relate to clinical response, OS, and as a bridge to curative therapy with hematopoietic stem cell transplant (HSCT). SAA patients treated with IST who received GTs at the National Institutes of Health between 2011 and 2020 were included. Primary outcomes were survival from first GT, including OS, survival to discharge, and survival to HSCT conditioning. Secondary outcomes included evaluation of response at 7 and 30 days after initiation of GTs based on clinical, microbiological, and radiographic criteria. Cox proportional-hazards model was used to determine impact of neutrophil response and infection type on survival. Kaplan-Meier estimators were used to assess OS. Twenty-eight SAA patients with median age 20 years (range 6-65 years) underwent 30 GT courses administered prior to (n=16), during (n=8), or after HSCT (n=6). Initial IST included horse antithymocyte globulin (hATG), cyclosporine (CSA), and Eltrombopag (n=11), hATG/CSA (n=8), cyclophosphamide/CSA (n=6), and hATG/CSA, and sirolimus (n=1). Two patients did not receive any IST and went directly to HSCT. A median of 8 granulocyte products per course (range 1-39 products) were administered over a median of 23.5 days (range 3-103 days), with a per-dose median of 1.28 x 10^9 granulocyte cells/kg (range 0.45-4.52 x 10^9). Indications for GT included invasive bacterial (n=15), fungal (n=12), and mixed (n=3) infections. Survival to discharge in GT course recipients who achieved complete response by day 7 or day 30 increased from 57% (4/7) to 85% (11/13), respectively. OS from initial GT was 50% at median length of follow up at 550.5 days (range 2-4213 days). Patients who achieved complete, partial, or stable response at 30 days had significantly improved OS compared to non-responders (p=0.0004) (Figure 1). Sixty-four percent (18/28) of patients survived to hospital discharge (Table 1). Sex, type of infection, or % of days with ANC >200 cells/mcL during the granulocyte course, were not predictive of survival (p=0.52, p=0.7, p=0.28 respectively). Eighteen of 21 (86%) patients awaiting HSCT during granulocyte therapy ultimately underwent transplant, and 62% (13/21) of them survived to discharge. Of three patients awaiting HSCT who did not receive HSCT, two died and one had hematopoietic recovery after IST and survived. Five patients who received HSCT but did not survive to discharge died due to progression of initial infection (n=3), graft-versus-host-disease (n=1), and secondary hemophagocytic lymphohistiocytosis (n=1). GTs at high doses can be a valuable adjunctive therapy to manage severe infections in SAA and may impact survival in those with improvement or stabilization of their underlying infection. OS in this population remains poor, but GTs may be a useful tool to bridge patients to curative treatment with HSCT. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Avatrombopag Added to Standard Immunosuppressive Therapy for Severe Aplastic Anemia

Acquired aplastic anemia is immune-mediated bone marrow failure disease. Antithymocyte globulin (ATG) and cyclosporine based immunosuppressive therapy (IST) is effective for severe aplastic anemia (SAA), but only 12-17% of patients achieve complete response at 6 months. Complete hematologic response predicts better survival of patients, so clinicians have been trying to further improve the complete response rate. Addition of eltrombopag improves both the overall response rate and complete response rate of SAA patients, but its hepatotoxicity is still worrying. Avatrombopag is a novel, oral, small-molecule thrombopoietin receptor agonist being developed to provide a predictable increase in platelet counts in immune thrombocytopenia and thrombocytopenia in patients with chronic liver disease. To date, there is no report on the effectiveness of avatrombopag in treating aplastic anemia. Here we enrolled 32 severe and very severe aplastic anemia (SAA/VSAA) patients who received ATG, cyclosporine and avatrombopag as first-line treatment between June 2021 and March 2022. Thirty-one patient received porcine ATG (20mg/kg.d for 5 consecutive days) and one patient received rabbit ATG (3mg/kg.d for 5 consecutive days). Avatrombopag was added within 3 months after ATG initiation at dose of 40-60mg per day and administered for at least 3 months. Cyclosporine was given orally at dose of 3.5-5mg/kg.d. There were 17 SAA patients and 15 VSAA patients. The median neutrophil count was 0.31 (range 0.01-1.01) ×109/L, median reticulocyte count was 8 (range 2-54) ×109/L, and median platelet count was 5 (range 1-16) ×109/L. All patients achieved the end-point of 3 months and 23 patients achieved end-point of 6 months. One patient with VSAA died at 1 month due to infections and was counted as no response at 3 months and 6 months. The rate of complete response was 15.6% and rate of overall response was 46.9% at 3 months. The rate of complete response at 6 months was 30.4% and rate of overall response was 65.2%. The complete response rate at 3 months and 6 months were both higher than historical results of standard IST (ATG and cyclosporine, 5.2% at 3 months and 14.6% at 6 months). Avatrombopag was safe, and there was no drug-related liver dysfunction. No patient discontinued avatrombopag due to adverse events. In conclusion, the addition of avatrombopag to IST was safe and associated with higher complete response rate among patients with SAA/VSAA.

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 6months was significantly higher in responders than in non-responders. Unexpectedly, we found that the increase in the proportion of NK cells at 6months 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.

Predictors of clonal evolution and myeloid neoplasia following immunosuppressive therapy in severe aplastic anemia.

Predictors, genetic characteristics, and long-term outcomes of patients with SAA who clonally evolved after immunosuppressive therapy (IST) were assessed. SAA patients were treated with IST from 1989-2020. Clonal evolution was categorized as "high-risk" (overt myeloid neoplasm [meeting WHO criteria for dysplasia, MPN or acute leukemia] or isolated chromosome-7 abnormality/complex karyotype without dysplasia or overt myeloid neoplasia) or "low-risk" (non-7 or non-complex chromosome abnormalities without morphological evidence of dysplasia or myeloid neoplasia). Univariate and multivariate analysis using Fine-Gray competing risk regression model determined predictors. Long-term outcomes included relapse, overall survival (OS) and hematopoietic stem cell transplant (HSCT). Somatic mutations in myeloid cancer genes were assessed in evolvers and in 407 patients 6 months after IST. Of 663 SAA patients, 95 developed clonal evolution. Pre-treatment age >48 years and ANC > 0.87 × 109/L were strong predictors of high-risk evolution. OS was 37% in high-risk clonal evolution by 5 years compared to 94% in low-risk. High-risk patients who underwent HSCT had improved OS. Eltrombopag did not increase high-risk evolution. Splicing factors and RUNX1 somatic variants were detected exclusively at high-risk evolution; DNMT3A, BCOR/L1 and ASXL1 were present in both. RUNX1, splicing factors and ASXL1 somaticmutations detected at 6 months after IST predicted high-risk evolution.

Immunosuppressive therapy in severe aplastic anemia

Severe aplastic anemia, a disease characterized by pancytopenia and a hypocellular marrow, is treatable by either immunosuppressive therapy (IST) or hematopoietic stem cell transplant. Much is understood about the immune-mediated pathophysiology of AA now, but the inciting factor remains elusive. Many groups around the globe contributed to understanding the disease pathophysiology and optimizing the IST regimen. Horse antithymocyte globulin and cyclosporine, the initial IST regimen, achieved a hematologic response rate in about 60% to 65% of treated patients, with less than 10% achieving a complete count recovery. However, adding a thrombopoietin receptor agonist, eltrombopag (EPAG), to IST improved these response rates to nearly 80% and an unprecedented increase in complete response to almost 40%. The latest report indicates that a high-risk clonal evolution to myeloid malignancies is not increased with hematopoietic stem cell stimulation by adding EPAG in the front line setting. Despite the great success of IST and EPAG in improving early outcomes, relapse remains a problem. Further optimization of upfront therapy and treatment protocol is needed to prevent relapses and decrease clonal evolution rates for even better long-term results.

Efficacy and safety analysis of eltrombopag and recombinant human thrombopoietin combined with immunosuppressive therapy for severe aplastic anemia

目的评价艾曲泊帕、重组人血小板生成素（Recombinant human thrombopoietin, rhTPO）联合标准免疫抑制治疗（Immunosuppressive therapy, IST）对重型再生障碍性贫血（Severe aplastic anemia, SAA）的疗效及安全性。方法回顾性分析2017年1月1日至2020年6月30日河南省肿瘤医院16例接受IST联合艾曲泊帕、rhTPO治疗的SAA患者，评价其疗效及安全性。结果艾曲泊帕、rhTPO联合标准IST治疗后3个月血液学反应率为81.3％，完全血液学缓解率为37.5％，6个月血液学反应率为87.5％，完全血液学缓解率为50.0％，脱离血小板输注中位时间为35（16～78）d，脱离红细胞输注中位时间为47.5（15～105）d，血小板输注中位量为5.5（3～20）U，红细胞输注中位量为6.5（2～16）U。结论艾曲泊帕联合rhTPO可提高SAA的IST血液学反应率，改善血液学缓解质量，且不良反应轻微。

Infusion of haploidentical hematopoietic stem cells combined with mesenchymal stem cells for treatment of severe aplastic anemia in adult patients yields curative effects

Background aimsDespite the great advances in immunosuppressive therapy for severe aplastic anemia (SAA), most patients are not completely cured. Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) has been recommended as an alternative treatment in adult SAA patients. However, haplo-HSCT presents a higher incidence of graft failure and graft-versus-host disease (GVHD). The authors designed a combination of haplo-HSCT and umbilical cord-derived mesenchymal stem cells (UC-MSCs) for treatment of SAA in adult patients and evaluated its effects. MethodsAdult patients (≥18 years) with SAA (N = 25) were given HLA-haploidentical hematopoietic stem cells (HSCs) combined with UC-MSCs after a conditioning regimen consisting of busulfan, cyclophosphamide, fludarabine and anti-thymocyte globulin and intensive GVHD prophylaxis, including cyclosporine, basiliximab, mycophenolate mofetil and short-term methotrexate. Additionally, the effects of the protocol in adult SSA patients were compared with those observed in juvenile SAA patients (N = 75). ResultsAll patients achieved myeloid engraftment after haplo-HSCT at a median of 16.12 days (range, 11–26). The median time of platelet engraftment was 28.30 days (range, 13–143). The cumulative incidence of grade II acute GVHD (aGVHD) at day +100 was 32.00 ± 0.91%. No one had grade III–IV aGVHD at day +100. The cumulative incidence of total chronic GVHD was 28.00 ± 0.85%. The overall survival was 71.78 ± 9.05% at a median follow-up of 42.08 months (range, 2.67–104). Promisingly, the protocol yielded a similar curative effect in both young and adult SAA patients. ConclusionsThe authors’ data suggest that co-transplantation of HLA-haploidentical HSCs and UC-MSCs may provide an effective and safe treatment for adult SAA.

Strong Predictors of Chromosomal Aberrations and Myeloid Neoplasia Following Immunosuppression Therapy for Severe Aplastic Anemia: A Retrospective Cohort Study

Introduction: Immune aplastic anemia (AA) is effectively treated with either immunosuppressive treatment (IST) or allogeneic hematopoietic stem cell transplant (HSCT). Clonal evolution remains the most feared long-term complication after IST. We investigated predictor factors, genetic characteristics, and long-term outcomes of patients who developed either secondary myeloid neoplasia or isolated chromosomal abnormalities without morphologic dysplasia after immunosuppression.Methods: All patients with severe AA treated at the NIH Clinical Center with IST from 1989-2020 who underwent clonal evolution were categorized as “high-risk” (overt myeloid neoplasia, or isolated chromosome 7 abnormality / complex cytogenetics) or “low-risk” (isolated chromosome abnormalities without overt myeloid neoplasia or dysplasia; isolated chromosome 7 abnormality or complex cytogenetics were characterized as high-risk). Univariable analysis was performed using the Fine-Gray competing risk regression model using death as a competing risk to determine predictors of clonal evolution. Classification and regression tree analysis of time to clonal evolution was performed on continuous baseline variables to partition the data based on the best categorical cutoff. Long term outcomes assessed included overall survival (OS) and HSCT. Error corrected next-generation sequencing (ECS) was used to assess for pathogenic somatic variants in known myeloid cancer genes in clonal evolvers both at time of evolution and in serial samples prior when available.Results: Of 659 patients with severe AA included in this study, 95 developed clonal evolution: 59 high-risk and 36 low-risk. Age >48 years at diagnosis and pre-treatment ANC >0.87x10 9/L were strong predictors of high-risk clonal evolution. High-risk clonal evolution was increased in patients aged >48 years, with cumulative incidence (CI) of 13.9% by 5 years compared to patients aged <48 years of 3.8% by 5 years (p<0.001). Baseline ANC >0.87 x10 9/L (independent of age) predicted an even higher risk of evolution; CI for high-risk evolution was 17% by 5 years (p<0.001). Combined high ANC and older age (>48 years) were prognostic of the greatest risk of high-risk evolution, with a hazard ratio (HR) of 5.51; conversely, ANC <0.87 x10 9/L and age <48 years was protective, with HR 0.32. High-risk clonal evolution was not significantly increased by use of eltrombopag with IST versus IST only (p=0.3), but there was an increase when all clonal evolution was considered (p=0.02). Overall survival in high-risk evolution was 35% at 5 years and in low-risk evolution was 84% (p<0.001). Patients with high-risk evolution who underwent HSCT (n=26) had better OS compared to those treated with chemotherapy or supportive care (p=0.005).RUNX1 (13 variants in 8 [35%] patients) and ASXL1 (13 variants in 10 [43%] patients) were the most frequent mutated genes at time of clonal evolution in high-risk patients, and BCOR/L1 (14 variants in 8 [32%] patients) was the most frequently mutated in the low-risk group. Longitudinal data were available in five high-risk and eight low-risk patients. Three of five high-risk patients had acquisition or expansion of RUNX1 clones at evolution. Small RUNX1 variants were present in two patients as early as three years prior to high-risk evolution. Splicing factor genes and RUNX1 somatic variants were detected exclusively in the high-risk group; DNMT3A, BCOR/L1 and ASXL1 gene mutations were present in both groups.Conclusion: Age and pre-treatment ANC strongly predict high-risk clonal evolution in AA patients after IST and may be used determine at-risk patients for long term follow-up. Outcomes in patients with low-risk evolution are favorable but poor in high-risk evolution without HSCT. The clonal landscape differs between high-risk and low-risk evolution; MDS-associated genetic mutations are enriched in high-risk evolution, in particular RUNX1. Further study of the role of RUNX1 in high-risk clonal evolvers may give insight into leukemogenesis in AA.Figure 1: Cumulative incidence (CI) of clonal evolution since immunosuppression with death treated as competing risk. (A) CI for development of all clonal evolution in patients >37 years (B) and high-risk clonal evolution in patients >48 years (C) CI for development of all clonal evolution when baseline ANC >0.87x10 9/L and (D) high-risk clonal evolution when baseline ANC >0.87x10 9/L. [Display omitted] DisclosuresYoung: Novartis: Research Funding.

Inefficacy of Immunosuppressive Therapy for Severe Aplastic Anemia Progressing From Non-SAA: Improved Outcome After Allogeneic Hematopoietic Stem Cell Transplantation.

Background and AimsThis study aimed at comparing the efficacy and safety of severe aplastic anemia (SAA) cases that had met the criteria for SAA at the time of diagnosis (group A) with SAA that had progressed from non-SAA (NSAA) (group B), both undergoing first-line immunosuppressive therapy (IST). Additionally, group B was compared with SAA that had progressed from NSAA and who had been treated by allogeneic hematopoietic stem cell transplantation (allo-HSCT) (group C).MethodsWe retrospectively compared 608 consecutive patients in group A (n = 232), group B (n = 229) and group C (n = 147) between June 2002 and December 2019. Six months after treatment, the rate of overall response and the fraction of patients who had achieved normal blood values, treatment-related mortality (TRM), secondary clonal disease, 5-year overall survival (OS) and failure-free survival (FFS) were indirectly compared between group A and group B, group B and group C.ResultsSix months after treatment, the rate of overall response and the fraction of patients who had achieved normal blood values in group A was higher than in group B (65.24% vs. 40.54%, P < 0.0001; 23.33% vs. 2.25%, P < 0.0001); the same was true for group C (92.50% vs. 2.25%, P < 0.0001). The rate of relapse in group B was higher than in group C (P < 0.0001), but there were no differences in TRM and secondary clonal disease (P > 0.05). There were no differences in estimated 5-year OS between groups A and B (83.8% ± 2.6% vs. 85.8% ± 2.6%, P = 0.837), or between B and C (85.8% ± 2.6% vs. 77.9% ± 3.4%, P = 0.051). The estimated 5-year FFS in groups A and C was higher than for group B (57.1% ± 3.3% vs. 39.7% ± 3.4%, P < 0.001; 76.7% ± 3.5% vs. 39.7% ± 3.4%, P < 0.0001).ConclusionThese results indicate that IST is less effective in SAA progressing from non-SAA but allo-HSCT can improve outcomes.

Full Dose Cyclophosphamide with the Addition of Fludarabine for Matched Sibling Transplants in Severe Aplastic Anemia

The recommended therapy for severe aplastic anemia (SAA) in younger patients with a matched sibling donor (MSD) is allogeneic hematopoietic cell transplantation (allo-HCT). A number of conditioning regimens and protocols have been used for these patients. Here we report a homogeneous cohort of SAA patients receiving a uniform transplantation protocol. This study is a retrospective analysis of 82 consecutive patients with SAA who underwent MSD allo-HCT at a single center. The median duration of follow-up for survivors was 100 months, the 10-year overall survival (OS) was 87.5%, and the 10-year event-free survival was 75.3%. The OS was 97.4% for "mobilized" bone marrow (BM) graft recipients and 78.9% for "nonmobilized" BM graft recipients (P=.01. The cumulative incidence of acute graft-versus-host disease (GVHD) was 25.6%, that of chronic GVHD was 27.16%, and that of graft failure was 16.2%. Recipient age ≥30 years and transplantation at >6 months after SAA diagnosis were associated with a increased risk of events. In the presence of a fully matched sibling donor, allo-HCT with a mobilized BM graft and fludarabine-cyclophosphamide conditioning is an efficacious and safe approach. Early transplantation is associated with a better outcome, emphasizing the importance of not delaying transplantation in these patients. Prospective trials are needed to determine the optimal regimen.

Predicting response of severe aplastic anemia to immunosuppression combined with eltrombopag.

Pretreatment blood counts, particularly an absolute reticulocyte count ≥25×109/L, correlate with response to immunosuppressive therapy in severe aplastic anemia. In recent trials, eltrombopag combined with standard immunosuppressive therapy yielded superior responses than those to immunosuppressive therapy alone. Our single institution retrospective study aimed to elucidate whether historical predictors of response to immunosuppressive therapy alone were also associated with response to immunosuppressive therapy plus eltrombopag. We sought correlations of blood counts, thrombopoietin levels and the presence of paroxysmal nocturnal hemoglobinuria clones with both overall and complete responses in 416 patients with severe aplastic anemia, aged 2-82 years (median, 30 years), initially treated with immunosuppressive therapy plus eltrombopag between 2012 and 2019 (n=176) or with immunosuppressive therapy alone between 1999 and 2010 (n=240). Compared to non-responders, patients in the group of overall responders to immunosuppressive therapy plus eltrombopag had significantly higher pretreatment absolute reticulocyte counts, higher neutrophil counts and reduced thrombopoietin levels, as also observed for the group treated with immunosuppressive therapy alone. Addition of eltrombopag markedly improved the overall response in subjects with an absolute reticulocyte count between 10-30×109/L from 60% (54 of 90) to 91% (62 of 68). Absolute lymphocyte count correlated with complete response in the groups treated with immunosuppressive therapy with or without eltrombopag, especially in adolescents aged ≥10 years and adults, but the correlation was reversed in younger children. Platelet count and the presence of a paroxysmal nocturnal hemoglobinuria clone did not correlate with responses to immunosuppressive therapy. Blood counts remain the best predictors of response to nontransplant therapies in severe aplastic anemia. Addition of eltrombopag to immunosuppressive therapy shifted patients with a lower absolute reticulocyte count into a better prognostic category.

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.

Pediatric Patients with Severe Aplastic Anemia Treated with Combined Immunosuppressive Therapy, Eltrombopag and Eculizumab and Their Clinical Course to Stem Cell Transplant

Acquired aplastic anemia (AA) in children is a rare disorder characterized by pancytopenia and hypocellular bone marrow. Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired clonal hematopoetic stem cell (HCT) disorder characterized by complemented-mediated hemolysis, thrombosis and bone marrow failure secondary to deficiency of glycosylphosphatidylinositol-anchored proteins (GPI-AP) on hematopoetic stem cells. PNH and acquired AA are closely related; up to 50% of patients with AA have detectable PNH-clones at the time of diagnosis and small percentage of them can have clonal expansion throughout their disease course requiring close monitoring. Current standard therapy for severe aplastic anemia (SAA) patients without matched related donor (MRD) is immunosuppressive therapy (IST) regimen with anti-thymoglobulin (ATG), cyclosporine (CSA), and recent addition of eltrombopag. Eculizumab is a recombinant humanized monoclonal antibody that blocks complement protein C5 and prevents cell lysis. While it has been shown to be effective in children with PNH, concomitant treatment with IST for patients with SAA is unknown. To our knowledge, there has been no pediatric data on combined IST, eltrombopag and eculizumab treatment for children with AA with clinically significant PNH clones. Here we retrospectively reviewed three pediatric patients with SAA with PNH clones treated with IST, eltrombopag and eculizumab and their unique clinical courses. Two out of three patients had high PNH clone size and were started on eculizumab prior to IST with improvement in transfusion intervals. Of the two, one had decrease in PNH clone size after IST but the other patient's clone size continued to increase despite two courses of IST. Finally, the third patient had a minor PNH clone and was not started on eculizumab prior to IST. He remained asymptomatic for over a year until he developed symptomatic PNH with large clone size and aplastic bone marrow. His clone size continued to increase with no improvement in transfusion frequency despite being started on eculizumab. However, steroids were started based on anecdotal literature and his transfusion frequency decreased subsequently. All three patients are in the process of going through matched unrelated donor stem cell transplants. Several studies have reported the presence of a minor PNH clone at the time of AA diagnosis was associated a favorable response to IST. In this case series, the patient with the smallest PNH clone size at the time of diagnosis of SAA had the best response to IST compared to the other two patients who had larger PNH clone populations. These findings suggest that even though minor PNH population may lead to better response to IST compared to absence of the clone, the correlation between clone size and prognosis is unclear. Further study with larger sample size is needed to investigate this relationship. However, regardless of the population size, all three patients were able to prolong transfusion intervals using eculizumab without significant side effects. As the adoption of eltrombopag with standard IST is evolving with ongoing study, the efficacy of incorporating eculizumab to decrease transfusion frequency in patients with PNH-clone in addition to eltrombopag/IST regimen should be further investigated. Disclosures No relevant conflicts of interest to declare.

CLL-155: Differential Diagnosis of Aplastic Anaemia in Chronic Lymphocytic Leukaemia

A 73-year-old lady presented in September of 2019 with pancytopenia on a background of 17p and 13q deleted chronic lymphocytic leukaemia (CLL) on ibrutinib. The diagnosis of CLL was made in 2008 and no treatment was required until she developed progressive cytopenias in January of 2019, with a lymphocyte count of 193.8 ×109/L. Fluorescence in-situ hybridisation (FISH) demonstrated 17p and 13q deletions and she was commenced on ibrutinib. She developed atrial fibrillation but otherwise tolerated the therapy well. She represented with significant fatigue and bleeding in September of 2019 and her blood count revealed a haemoglobin (Hb) of 8.2 g/dL, a platelet count of 6 ×109/L, a lymphocyte count of 32 ×109/L, a neutrophil count of 0.24 ×109/L and a reticulocyte count of References [1] Zonder JA, Keating M, Schiffer CA. Chronic Lymphocytic Leukemia presenting in association with Aplastic Anemia. Am. J. Hematol. 2002 71:323–327. [2] Castiglioni MG, Scatena P, Pandolfo C et al. Rituximab Therapy of Severe Aplastic Anemia Induced by Fludarabine and Cyclophosphamide in a Patient Affected by B-cell Chronic Lymphocytic Leukemia. 2006 Sep;47(9):1985-6. [3] Singal R, Winfield DA, Greaves M. Bone marrow aplasia in B cell chronic lymphocytic leukaemia: Successful treatment with antithymocyte globulin. J Clin Pathol 1991; 44:954-956. [4] Vitale C, Ahn IE, Sivina M et al. Autoimmune cytopenias in patients with chronic lymphocytic leukemia treated with ibrutinib. Haematologica 2016; 101:e257.