Eltrombopag added to immunosuppression for children with treatment-naïve severe aplastic anaemia

Adjunctive effects of eltrombopag on immunosuppressive therapy for childhood aplastic anemia

Eltrombopag is used with first-line immunosuppressive therapy for adult aplastic anemia, although its practical utility in childhood remains unclear. We retrospectively analyzed the outcomes of pediatric patients who received eltrombopag in Japan. Of the 27 eligible patients, 23 (85%) were previously treated, and 15 (56%) had severe or very-severe disease. Seventeen (63%) received eltrombopag with or after rabbit anti-thymocyte globulin plus cyclosporin-A. Within the first year of eltrombopag therapy, 12 patients showed a good or partial response, 15 showed no response, and 8 non-responders successfully underwent hematopoietic cell transplantation. Within the first 3 months after eltrombopag therapy, all but one of the transfusion-dependent responders became transfusion-independent. At 12 months, 6 of 12 responders were disease-free off-treatment. The one-year overall response rate was higher for severe or very-severe than non-severe cases (p = 0.006). Multivariable analysis showed that very-severe disease at the start of eltrombopag therapy was a predictor of being disease-free off-treatment (p = 0.03). No cytogenetic abnormalities developed, but myelofibrosis occurred 4 months after eltrombopag therapy in one non-responder with very-severe disease. The first 3 months' response to adjunctive eltrombopag may guide to the safe and effective use for the cure of disease, although prospective trials are needed to determine its long-term effects.

Allogeneic Hematopoietic Cell Transplantation for the Treatment of Severe Aplastic Anemia: Evidence-Based Guidelines From the American Society for Transplantation and Cellular Therapy

Allogeneic hematopoietic cell transplantation (HCT) is a potentially curative treatment for severe aplastic anemia (SAA). Existing guidance about HCT in SAA is primarily derived from expert reviews, registry data and societal guidelines; however, transplant-specific guidelines for SAA are lacking. A panel of SAA experts, both pediatric and adult transplant physicians, developed consensus recommendations using Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) methodology employing a GRADE guideline development tool. The panel agrees with previous recommendations for the preferential use of bone marrow as a graft source and the use of rabbit over horse antithymocyte globulin (ATG) for HCT conditioning. Fludarabine containing regimens are preferred for patients at high risk of graft failure and those receiving matched unrelated or haploidentical donor transplant. Given advancements in HCT, the panel does not endorse the historical 40-year age cut-off for considering upfront HCT in adults, acknowledging that fit older patients may also benefit from HCT. The panel also endorses increased utilization of HCT by prioritizing matched unrelated or haploidentical donor HCT over immunosuppressive therapy in children and adults who lack a matched related donor. Finally, the panel suggests either calcineurin inhibitor plus methotrexate or post-transplant cyclophosphamide-based graft-versus-host disease (GVHD) prophylaxis for matched related or matched unrelated donor recipients. These recommendations reflect a significant advancement in transplant strategies for SAA and highlight the importance of ongoing and further research to revisit current evidence in terms of donor choice, conditioning chemotherapy, GVHD prophylaxis and post-transplant immunosuppression.

Safety and efficacy of eltrombopag in patients with aplastic anemia: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

This article conducts a systematic review of eltrombopag combined with immunosuppressive therapy for the treatment of aplastic anemia (AA), to demonstrate the effectiveness and safety of eltrombopag.

METHODS

PubMed, Cochrane Library, Embase, OVID, Web of Science, China National Knowledge Infrastructure, and Wanfang databases were searched. Studies that met the inclusion criteria were collected, ranging from the establishment of the database to August 2023. Two reviewers performed meta-analyses using the Cochrane systematic review method and RevMan 5.3 software.

RESULTS

This meta-analysis enrolled 5 studies with a total of 542 AA patients, including 274 in the experimental group and 268 in the control group. Meta-analyses were performed for efficacy and adverse reactions. The endpoint of effects included 6-month complete response (CR), 6-month partial response (PR), and 6-month overall response (OR). Eltrombopag combined with immunotherapy showed significant improvements in 6-month CR (OR: 2.20; 95% CI;1.54-3.12; P < 0.0001) and 6-month OR (OR = 3.66, 95% CI 2.39-5.61, P < 0.001)compared to immunosuppressive therapy for AA patients. In terms of safety, eltrombopag combined with immunosuppressive therapy showed significantly increased pigment deposition and abnormal liver function compared to immunosuppressive therapy alone.

CONCLUSION

Compared to immunosuppressive therapy alone, eltrombopag combined with immunosuppressive therapy showed significant improvements in 6-month CR and 6-month OR. However, it also resulted in increased pigment deposition and abnormal liver function in terms of safety.

Diagnosis and management of acquired aplastic anemia in childhood. Guidelines from the Marrow Failure Study Group of the Pediatric Haemato-Oncology Italian Association (AIEOP)

Acquired aplastic anemia (AA) is a rare heterogeneous disorder characterized by pancytopenia and hypoplastic bone marrow. The incidence is 2-3 per million population per year in the Western world, but 3 times higher in East Asia. Survival in severe aplastic anemia (SAA) has improved significantly due to advances in hematopoietic stem cell transplantation (HSCT), immunosuppressive therapy, biologic agents, and supportive care. In SAA, HSCT from a matched sibling donor (MSD) is the first-line treatment. If a MSD is not available, options include immunosuppressive therapy (IST), matched unrelated donor, or haploidentical HSCT. The purpose of this guideline is to provide health care professionals with clear guidance on the diagnosis and management of pediatric patients with AA. A preliminary evidence-based document prepared by a group of pediatric hematologists of the Bone Marrow Failure Study Group of the Italian Association of Pediatric Hemato-Oncology (AIEOP) was discussed, modified and approved during a series of consensus conferences that started online during COVID 19 and continued in the following years, according to procedures previously validated by the AIEOP Board of Directors.

Treatment of relapsed/refractory 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 relapsed or refractory SAA.

Efficacy, Safety, and Population Pharmacokinetics of Eltrombopag in Children with Different Severities of Aplastic Anemia

Eltrombopag was approved as a first-line treatment for patients older than 2 years old with severe aplastic anemia (SAA). However, data on eltrombopag in children with different types of aplastic anemia (AA), especially non-severe AA (NSAA), are limited. We performed a prospective, single-arm, and observational study to investigate eltrombopag's efficacy, safety, and pharmacokinetics in children with NSAA, SAA, and very severe AA (VSAA). The efficacy and safety were assessed every 3 months. The population pharmacokinetic (PPK) model was used to depict the pharmacokinetic profile of eltrombopag. Twenty-three AA children with an average age of 7.9 (range of 3.0-14.0) years were enrolled. The response (complete and partial response) rate was 12.5%, 50.0%, and 100.0% after 3, 6, and 12 months in patients with NSAA. For patients with SAA and VSAA, these response rates were 46.7%, 61.5%, and 87.5%. Hepatotoxicity occurred in one patient. Fifty-three blood samples were used to build the PPK model. Body weight was the only covariate for apparent clearance (CL/F) and volume of distribution. The allele-T carrier of adenosine triphosphate-binding cassette transporter G2 was found to increase eltrombopag's clearance. However, when normalized by weight, the clearance between the wild-type and variant showed no statistical difference. In patients with response, children with NSAA exhibited lower area under the curve from time zero to infinity, higher CL/F, and higher weight-adjusted CL/F than those with SAA or VSAA. However, the differences were not statistically significant. The results may support further individualized treatment of eltrombopag in children with AA.

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.

Romiplostim for Treatment of Children and Young Adults With Severe Aplastic Anemia and Myelodysplastic Syndrome

Thrombopoietin receptor agonists (TPO-RAs) induce trilineage hematopoiesis under conditions with acquired hematopoietic failure. We evaluated safety, tolerability, and preliminary efficacy of a TPO-RA, romiplostim (Nplate), with or without standard-of-care immunosuppressive therapy (±IST) for children (ages < 21 y) with newly diagnosed and relapsed/refractory severe aplastic anemia (SAA) and myelodysplastic syndrome (MDS). Data were collected from an observational study and a single arm interventional pilot study. The safety outcome was treatment-related adverse events (AEs). Efficacy was evaluated by complete hematopoietic response (CHR) at week 24. Romiplostim was commenced at 5 µg/kg/week, with dose escalation of 2.5 µg/kg/week (maximum, 20 µg/kg/dose) based on platelet response. Romiplostim was continued until CHR was observed. Ten subjects (SAA, 9 [IST, 4; without IST, 5]; MDS, 1) completed the study (median age: 9.2 y). Median romiplostim dose was 10 µg/kg/week (range: 5 to 17.5 µg/kg/week). The cumulative incidence of CHR was 70.4% (95% CI, 20.2%-92.6%). Among 21 AEs (Grade 1 to 3), 3 were attributed to romiplostim. At a median posttherapy follow-up of 10.9 months (range: 0.7 to 77.5), no clonal evolution, bone marrow fibrosis or mortality was reported. This proof-of-concept study provides data about short-term safety, tolerability, and preliminary efficacy of romiplostim (±IST) for treatment of pediatric SAA/MDS.

Eltrombopag combined with immunosuppressive therapy for pediatric severe aplastic anemia

BACKGROUND

Severe aplastic anemia (SAA) is caused by immune-mediated destruction. Standard immunosuppressive therapy (IST) is effective but needs to be improved.

METHODS

The data of patients with SAA and received IST were analyzed retrospectively to conducted this historical control study.

RESULTS

A total of 115 SAA patients (60 males; median age of 5.77 years and median follow-up time of 45 months) were enrolled in this study. The complete response rates (CRR) of the eltrombopag group at 3 and 6 months were higher than the control group (30.3% vs.8.2% at 3 months; 50.0% vs. 10.2% at 6 months). The overall response rates (ORR) showed no differences. There were significant differences in the times from G-CSF, Red blood cell transfusion, and Platelet transfusion between the two groups. No difference in overall survival (OS), event-free survival (EFS), and relapse rate between two groups. There is no variable were associated with prognosis in both groups.

CONCLUSION

Addition of eltrombopag to IST confers faster hematological response and higher early hematological response in pediatric SAA patients.

IMPACT

Addition of eltrombopag to standard immunosuppressive therapy confers faster hematological response and higher early hematological response in pediatric severe aplastic anemia patients. Eltrombopag showed reliable safety but had no impact on long-term response and prognosis. This article is a historical controlled study consisting of 115 pediatric severe aplastic anemia patients and makes up for the lack of clinical data deficient on pediatric severe aplastic anemia with TPO-RA combined with IST.

Resolvin E1 improves efferocytosis and rescues severe aplastic anemia in mice

Severe aplastic anemia (SAA) is a rare, fatal disease characterized by severe cytopenias and loss of hematopoietic stem cells (HSCs). Immune-mediated destruction and inflammation are known drivers of SAA, however, the underlying mechanisms driving persistent inflammation are unknown. Current treatments for SAA rely on immunosuppressive therapies or HSC transplantation, however, these treatments are not always effective. Using an established mouse model of SAA, we observed a significant increase in apoptotic cells within the bone marrow (BM) and impaired efferocytosis in SAA mice, relative to radiation controls. Single-cell transcriptomic analysis revealed heterogeneity among BM monocytes and unique populations emerged during SAA characterized by increased inflammatory signatures and significantly increased expression of Sirpa and Cd47. CD47, a "don't eat me" signal, was increased on both live and apoptotic BM cells, concurrent with markedly increased expression of signal regulatory protein alpha (SIRPα) on monocytes. Functionally, SIRPα blockade improved cell clearance and reduced accumulation of CD47-positive apoptotic cells. Lipidomic analysis revealed a reduction in the precursors of specialized pro-resolving lipid mediators (SPMs) and increased prostaglandins in the BM during SAA, indicative of impaired inflammation resolution. Specifically, 18-HEPE, a precursor of E-series resolvins, was significantly reduced in SAA-induced mice relative to radiation controls. Treatment of SAA mice with Resolvin E1 (RvE1) improved efferocytic function, BM cellularity, platelet output, and survival. Our data suggest that impaired efferocytosis and inflammation resolution contributes to SAA progression and demonstrate that SPMs, such as RvE1, offer new and/or complementary treatments for SAA that do not rely on immune suppression.

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.

Efficacy and safety of immunosuppressive therapy combined with eltrombopag for severe aplastic anemia: a systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

Immunosuppressive therapy (IST) is the first choice for severe aplastic anemia (SAA) patients with hematopoietic stem cell transplantation (HSCT) limitation, and the main factor limiting its efficacy is too few residual hematopoietic stem/progenitor cells (HSPC). Eltrombopag (EPAG), as a small molecule thrombopoietin receptor agonist, can stimulate the proliferation of residual HSPC and restore the bone marrow hematopoietic function of patients. In recent years, many studies have observed the efficacy and safety of IST combined with EPAG in the treatment of SAA, but the results are still controversial. The aim of this study is to systematically evaluate the efficacy and safety of IST combined with or without EPGA in the treatment of SAA.

METHODS

We conducted a systematic review of all relevant literature published up to January 19, 2024. Pooled odds ratio (OR) was calculated to compare the rates, along with 95% confidence intervals (CI) and p value to assess whether the results were statistically significant by Review Manager 5.4.1. The p values for the interactions between each subgroup were calculated by Stata 15.1. The Newcastle-Ottawa Scale and the Cochrane bias risk assessment tools were respectively used to evaluate the quality of the literature with cohort studies and randomized controlled trials. The Review Manager 5.4.1 and Stata 15.1 were used to assess bias risk and perform the meta-analysis.

RESULTS

A total of 16 studies involving 2148 patients were included. The IST combined with the EPAG group had higher overall response rate (ORR) than the IST group at 3 months (pooled OR = 2.10, 95% CI 1.58-2.79, p < 0.00001) and 6 months (pooled OR = 2.13, 95% CI 1.60-2.83, p < 0.00001), but the difference between the two groups became statistically insignificant at 12 months (pooled OR = 1.13, 95% CI 0.75-1.72, p = 0.55). The results of complete response rate (CRR) (pooled OR at 3 months = 2.73, 95% CI 1.83-4.09, p < 0.00001, 6 months = 2.76, 95% CI 2.08-3.67, p < 0.00001 and 12 months = 1.38, 95% CI 0.85-2.23, p = 0.19) were similar to ORR. Compared with the IST group, the IST combined with the EPAG group had better overall survival rate (OSR) (pooled OR = 1.70, 95% CI 1.15-2.51, p = 0.008), but there were no statistically significant differences in event-free survival rate (EFSR) (pooled OR = 1.40, 95% CI 0.93-2.13, p = 0.11), clonal evolution rate (pooled OR = 0.68, 95% CI 0.46-1.00, p = 0.05) and other adverse events between the two groups. The results of subgroup analysis showed that different ages were a source of heterogeneity, but different study types and different follow-up times were not. Moreover, all p-values for the interactions were greater than 0.05, suggesting that the treatment effect was not influenced by subgroup characteristics.

CONCLUSION

EPAG added to IST enables patients to achieve earlier and faster hematologic responses with a higher rate of complete response. Although it had no effect on overall EFSR, it improved OSR and did not increase the incidence of clonal evolution and other adverse events.

Upfront Umbilical Cord Blood Transplantation Versus Immunosuppressive Therapy for Pediatric Patients With Idiopathic Severe Aplastic Anemia

Umbilical cord blood transplantation (UCBT) has been rarely reported as a first-line treatment for idiopathic severe aplastic anemia (SAA) patients lacking HLA-matched sibling donors (MSD). Our study aimed to compare the clinical outcomes of pediatric SAA patients who received UCBT and immunosuppressive therapy (IST) upfront. A retrospective analysis was performed on 43 consecutive patients who received frontline IST (n = 17) or UCBT (n = 26) between July 2017 and April 2022. The 3-year overall survival (OS) was comparable between the UCBT and IST groups (96.2% versus 100%, P = .419), while the 3-year event-free survival (EFS) was significantly better in the former than in the latter (88.5% versus 58.8%, P = .048). In the UCBT group, 24 patients achieved successful engraftment, 2 patients developed severe acute graft-versus-host disease (aGVHD), no extensive chronic GVHD (cGVHD), and a high GVHD-free, failure-free survival (GFFS) of 84.6% at 3 years. After 1 year of treatment, 12 patients in the IST group responded, while 5 patients did not achieve remission and 2 patients had disease relapse. At both 3 and 6 months after treatment, the proportion of transfusion-independent patients was higher in the UCBT group than in the IST group. Faster immune recovery and earlier transfusion independence further reduced the risk of infection and bleeding, thereby improving health-related quality of life in the UCBT-treated group. Our results suggested that UCBT as upfront therapy may be an effective and safe option for pediatric SAA patients, with favorable outcomes in experienced centers.

Recent advances in the diagnosis and treatment of pediatric acquired aplastic anemia

Acquired aplastic anemia (AA) in children is a rare bone marrow failure that requires several special considerations for its diagnosis and treatment compared with that in adults. The most common issue is the differential diagnosis with refractory cytopenia of childhood and inherited bone marrow failure syndromes, which is crucial for making decisions on the appropriate treatment for pediatric AA. In addition to detailed morphological evaluation, a comprehensive diagnostic work-up that includes genetic analysis using next-generation sequencing will play an increasingly important role in identifying the underlying etiology of pediatric AA. When discussing treatment strategies for children with acquired AA, the long-term sequelae and level of hematopoietic recovery that affect daily or school life should also be considered, although the overall survival rate has reached 90% after immunosuppressive therapy or hematopoietic cell transplantation (HCT). Recent advances in HCT for pediatric patients with acquired AA have been remarkable, with the successful use of upfront bone marrow transplantation from a matched unrelated donor, unrelated cord blood transplantation or haploidentical HCT as salvage treatment, and fludarabine/melphalan-based conditioning regimens. This review discusses current clinical practices in the diagnosis and treatment of acquired AA in children based on the latest data.

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

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

Multicenter evaluation of the addition of eltrombopag to immunosuppressive therapy for adults with severe aplastic anemia

Eltrombopag has been shown to improve response rates when added to standard therapy in adults with severe aplastic anemia in controlled trial settings. However, outcomes in real-world populations have mostly been examined in small retrospective studies. This robust, multicenter, retrospective cohort study across six academic health systems compared outcomes in patients who received immunosuppressive therapy with or without eltrombopag. The study included 82 patients who received front-line therapy from January 2014 to August 2021. Overall response rates at 6 months did not differ significantly for patients receiving eltrombopag versus immunosuppressive therapy alone (58% v. 65%, p = 0.56). However, complete response rates at 6 and 12 months were over two times higher in the eltrombopag arm (29% v. 12%, p = 0.06 and 48% v. 18%, p = 0.005). Rates of hepatotoxicity were similar across both arms. Eltrombopag addition did not impact overall survival (median not reached in either arm at 2 years, p = 0.86) or disease-free survival (median not reached v. 13.3 months at 2 years, p = 0.20). Eltrombopag may not produce as large of a benefit in real-world settings compared to controlled trial settings but may offer patients deeper responses with similar rates of toxicity to immunosuppressive therapy alone.

Single-cell genomics in acquired bone marrow failure syndromes

Mechanistic studies of immune bone marrow failure are difficult because of the scarcity of residual cells, the involvement of multiple cell types, and the inherent complexities of hematopoiesis and immunity. Single-cell genomic technologies and bioinformatics allow extensive, multidimensional analysis of a very limited number of cells. We review emerging applications of single-cell techniques, and early results related to disease pathogenesis: effector and target cell populations and relationships, cell-autonomous and nonautonomous phenotypes in clonal hematopoiesis, transcript splicing, chromosomal abnormalities, and T-cell receptor usage and clonality. Dense and complex data from single-cell techniques provide insights into pathophysiology, natural history, and therapeutic drug effects.

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

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

Resolvin E1 improves efferocytosis and rescues severe aplastic anemia in mice

Current treatments for severe aplastic anemia (SAA) rely on hematopoietic stem cell (HSC) transplantation and immunosuppressive therapies, however these treatments are not always effective. While immune-mediated destruction and inflammation are known drivers of SAA, the underlying mechanisms that lead to persistent inflammation are unknown. Using an established mouse model of SAA, we observed a significant increase in apoptotic cells within the bone marrow (BM) and demonstrate impaired efferocytosis in SAA mice, as compared to radiation controls. Single-cell transcriptomic analysis revealed heterogeneity among BM monocytes and unique populations emerged during SAA characterized by increased inflammatory signatures and significantly increased expression of Sirpa and Cd47. CD47, a "don't eat me" signal, was increased on both live and apoptotic BM cells, concurrent with markedly increased expression of signal regulatory protein alpha (SIRPα) on monocytes. Functionally, SIRPα blockade improved cell clearance and reduced accumulation of CD47-positive apoptotic cells. Lipidomic analysis revealed a reduction in the precursors of specialized pro-resolving lipid mediators (SPMs) and increased prostaglandins in the BM during SAA, indicative of impaired inflammation resolution. Specifically, 18-HEPE, a precursor of E-series resolvins, was significantly reduced in SAA-induced mice relative to radiation controls. Treatment of SAA mice with Resolvin E1 (RvE1) improved efferocytic function, BM cellularity, platelet output, and survival. Our data suggest that impaired efferocytosis and inflammation resolution contributes to SAA progression and demonstrate that SPMs, such as RvE1, offer new and/or complementary treatments for SAA that do not rely on immune suppression.

Efficacy of Eltrombopag with Immunosuppressive Therapy Versus Immunosuppressive Therapy Alone on Severe Aplastic Anaemia: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVE

Severe aplastic anaemia (SAA) is a syndrome of bone marrow failure caused by T cell-mediated destruction of haematopoietic stem cells and progenitor cells. Whether patients with SAA should be treated with eltrombopag (EPAG) and immunosuppressive therapy (IST) or IST alone remains debatable. Therefore, we conducted this meta-analysis to compare the efficacy of eltrombopag + IST with that of IST alone in patients with SAA and to assess the difference in the efficacy of eltrombopag in adults and children.

METHODS

We performed this meta-analysis by retrieving studies that met the inclusion and exclusion criteria from PubMed, EMBASE, and the Cochrane Library up to 1 January 2023. We used a random-effects model to calculate odds ratios (ORs) with 95% confidence intervals (CIs) for primary and secondary outcomes. I² statistics were used to evaluate the heterogeneity of the included studies.

RESULTS

Six studies involving a total of 699 patients were included. In terms of the primary outcomes, our pooled results indicated that patients treated with EPAG + IST had a higher 6-month overall response rate (OR = 2.25; 95% CI, 1.60-3.16; p < 0.00001), a higher 6-month complete response rate (OR = 2.61; 95% CI, 1.82-3.74; p < 0.00001), and a lower 6-month nonresponse rate (OR = 0.32; 95% CI, 0.19-0.52; p < 0.00001). However, there was no significant difference in the rate of 6-month partial response (OR = 0.94; 95% CI, 0.49-1.81; p = 0.85).

CONCLUSION

This meta-analysis indicated that patients treated with additional eltrombopag for IST may have a higher rate of haematological response.

The efficacy and the safety of eltrombopag in pediatric patients with severe aplastic anemia: a systematic review

Background

Acquired aplastic anemia (AAA) in pediatric patients is a rare disorder characterized by hypocellular bone marrow and pancytopenia. Eltrombopag, an oral thrombopoietin receptor agonist, provides a hematologic improvement in adults with severe aplastic anemia (SAA) refractory to immunosuppressive therapy (IST). The association of ELT and IST was approved by the US Food and Drug Administration (FDA) for adults and children ≥2 years of age as a first-line treatment for SAA. However, the effects of ELT on pediatric patients with SAA remain controversial and limited.

Methods and findings

We conducted a systematic review of the most recent literature from Pubmed, Web of Science, and Embase, published up to 20th December 2022, in order to evaluate the available evidence on the efficacy and safety of ELT added to IST for the treatment of SAA in the pediatric population.

Conclusion

Eltrombopag added to the IST has shown a good safety profile, without manifestations of excessive toxic effects, although not all the results obtained from our studies support the addition of ELT to the IST in the first-line treatment of children with SAA.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, identifier: CRD42022325859.

Hepatitis-associated Aplastic Anemia

Hepatitis-associated aplastic anemia (HAAA) accounts for 4% of autoimmune hepatitis in children. An episode of seronegative autoimmune hepatitis is followed a few days or months later by aplastic anemia or full aplasia. This autoimmune disease could be due to a regulation defect in the immune response to a viral trigger, in a genetically predisposed individual. Other causes of hepatitis or aplastic anemia have to be ruled out. Steroids and azathioprine usually control the liver damage but do not prevent the development of aplastic anemia. Aplastic anemia is treated with either hematopoietic stem cell transplantation in patients with a sibling donor or anti-thymocyte globulins and cyclosporine. We propose guidelines to explore and treat this rare disease. We emphasize on the necessary close collaboration between hepatologists and hematologists.

Iron chelation of hetrombopag in aplastic anemia: a post hoc analysis of a phase II study

Hetrombopag is the only CFDA-approved thrombopoietin (TPO) receptor agonist for severe aplastic anemia (SAA) in China. Its chemical structure has an iron chelation domain. To explore the iron chelation effect of hetrombopag, we performed a post hoc analysis of the phase II clinical trial (NCT03557099). Thirty-five immunosuppressive therapy (IST)-refractory SAA patients were enrolled in the study, and the longitudinal changes of serum ferritin (SF) were assessed. At 18 weeks post-hetrombopag initiation, 51.4% of patients showed decreased SF levels by a median of 49.0 (18.1-95.5) % from baseline (median ΔSF decrease value, 917.2 ng/ml, range from 104.0 to 7030.0 ng/ml). A decrease in SF was found in 75.0% of hematologic responders and 31.6% of non-responders. Among the 24 patients with iron overload, 12 had decreased SF levels by up to 51% of the baseline. Patients with normal SF levels also showed decreased SF levels, and iron deficiency occurred in two patients. In conclusion, hetrombopag showed a powerful and rapid iron chelation effect.

Long-term eltrombopag for bone marrow failure depletes iron

Eltrombopag (EPAG) has been approved for the treatment of aplastic anemia and for immune thrombocytopenia, and a subset of patients require long-term therapy. Due to polyvalent cation chelation, prolonged therapy leads to previously underappreciated iron depletion. We conducted a retrospective review of patients treated at the NIH for aplastic anemia, myelodysplastic syndrome, and unilineage cytopenias, comparing those treated with EPAG to a historical cohort treated with immunosuppression without EPAG. We examined iron parameters, duration of therapy, response assessment, relapse rates, and common demographic parameters. We included 521 subjects treated with (n = 315) or without EPAG (n = 206) across 11 studies with multiyear follow-up (3.6 vs. 8.5 years, respectively). Duration of EPAG exposure correlated with ferritin reduction (p = 4 × 10^-14 ) regardless of response, maximum dose, or degree of initial iron overload. Clearance followed first-order kinetics with faster clearance (half-life 15.3 months) compared with historical responders (47.5 months, p = 8 × 10^-10 ). Risk of iron depletion was dependent upon baseline ferritin and duration of therapy. Baseline ferritin did not correlate with response of marrow failure to EPAG or to relapse risk, and timing of iron clearance did not correlate with disease response. In conclusion, EPAG efficiently chelates total body iron comparable to clinically available chelators. Prolonged use can deplete iron and ultimately lead to iron-deficiency anemia mimicking relapse, responsive to iron supplementation.

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

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

New Trends of Nontransplant therapy for Acquired Aplastic Anemia

Aplastic anemia (AA) is a hematological disease that is characterized by pancytopenia and hypofunctional bone marrow hematopoiesis. Patients with AA are treated with either immunosuppressive therapy (IST) using anti-thymocyte globulin (ATG) and Cyclosporine (CsA) or hematopoietic stem cell transplantation (HSCT), if a matched donor is available. The standard IST regimen for AA patients which results in response rates up to 70%, and even higher overall survival. However, primary and secondary failures after IST remain frequent, and to date all attempts aiming to overcome this problem have been unfruitful. The nontransplant therapeutic options for AA have significantly expanded during the last few years. Here, we review the new trends of nontransplant therapy for AA and summarize the current therapeutic effect of AA.

Efficacy of eltrombopag with immunosuppressive therapy for children with acquired aplastic anemia

BACKGROUND

Eltrombopag (EPAG), an oral thrombopoietin receptor agonist (TPO-RA), has been proven to improve the hematologic response without increasing toxic effects as a first-line therapy combined with standard immunosuppressive treatment (IST) in adults with severe aplastic anemia (SAA). Nevertheless, the clinical evidence on the efficacy of EPAG in children with acquired aplastic anemia is limited and controversial.

METHODS

We performed a single-center, retrospective study to analyze the clinical outcomes of fifteen patients aged ≤18 years with newly diagnosed acquired SAA who received first-line IST and EPAG (EPAG group) compared with those of forty-five patients who received IST alone (IST group) by propensity score matching (PSM).

RESULTS

There was no difference in the overall response (OR) rate between the EPAG group and IST group (53.3% vs. 46.7% at 3 months, P = 0.655; 66.7% vs. 57.8% at 6 months, P = 0.543), but the complete response (CR) rate was statistically significant (20.0% vs. 4.4% at 3 months, P = 0.094; 46.7% vs. 13.3% at 6 months, P = 0.012). The median time to achieve a hematological response in the EPAG and IST groups was 105 days and 184 days, respectively. No difference was observed in the event-free survival (EFS) or overall survival (OS) rates.

CONCLUSION

Adding EPAG to standard IST as the first-line treatment for children with acquired SAA improved the rapidity of hematological response and the CR rate but did not improve the OR or EFS rates.

Fludarabine-Cyclophosphamide-Based Conditioning with Antithymocyte Globulin Serotherapy Is Associated with Durable Engraftment and Manageable Infections in Children with Severe Aplastic Anemia

Severe aplastic anemia (SAA) is a bone marrow failure syndrome that can be treated with hematopoietic cell transplantation (HCT) or immunosuppressive (IS) therapy. A retrospective cohort of 56 children with SAA undergoing transplantation with fludarabine-cyclophosphamide-ATG-based conditioning (FluCyATG) was analyzed. The endpoints were overall survival (OS), event-free survival (EFS), cumulative incidence (CI) of graft versus host disease (GVHD) and CI of viral replication. Engraftment was achieved in 53/56 patients, and four patients died (two due to fungal infection, and two of neuroinfection). The median time to neutrophil engraftment was 14 days and to platelet engraftment was 16 days, and median donor chimerism was above 98%. The overall incidence of acute GVHD was 41.5%, and that of grade III-IV acute GVHD was 14.3%. Chronic GVHD was diagnosed in 14.2% of children. The probability of 2-year GVHD-free survival was 76.1%. In the univariate analysis, a higher dose of cyclophosphamide and previous IS therapy were significant risk factors for worse overall survival. Episodes of viral replication occurred in 33/56 (58.9%) patients, but did not influence OS. The main advantages of FluCyATG include early engraftment with a very high level of donor chimerism, high overall survival and a low risk of viral replication after HCT.

Thrombopoietin receptor agonists for marrow failure: A concise clinical review

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

Thrombopoietin Receptor Agonists (TPO-RAs): Drug Class Considerations for Pharmacists

The thrombopoietin receptor agonists (TPO-RAs) romiplostim, eltrombopag, avatrombopag, and lusutrombopag carry unique US Food and Drug Administration (US FDA)- and European Medicines Agency (EMA)-approved indications and may be used to increase platelet counts in a variety of conditions. Current indications for available TPO-RAs include treatment of chronic immune thrombocytopenia (ITP) in cases of insufficient response to prior treatment (avatrombopag, eltrombopag, romiplostim), management of thrombocytopenia in adult patients with chronic liver disease who are scheduled to undergo a procedure (avatrombopag, lusutrombopag), management of severe aplastic anemia (eltrombopag), and management of thrombocytopenia associated with interferon-based therapy for hepatitis C (eltrombopag). Across current indications, pharmacists can assist in stabilizing platelet counts and help to reduce large undulations commonly seen when starting, stopping, or transitioning between these agents. If therapy modifications may benefit the patient, pharmacists should discuss possible changes with the patient's treatment team or treating physician. When used for ITP, romiplostim, eltrombopag, and avatrombopag stimulate TPO receptors on hematopoietic stem cells (also known as c-Mpl, or CD110) to promote platelet production; however, romiplostim is the only TPO-RA that binds at the same site as endogenous TPO. These subtle mechanistic differences may explain why switching TPO-RA may be clinically advantageous in some situations. As pharmacists are called to counsel patients on TPO-RA use, a deep understanding of potential adverse events and management strategies, as well as appropriate monitoring, will increase the likelihood that patients meet their goals of therapy in the shortest timeframe. Other uses of TPO-RAs are also discussed in this review, including use following hematopoietic stem cell transplant, use in myelodysplastic syndrome, and use in chemotherapy-induced thrombocytopenia.

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.