Treatment Of Severe Aplastic Anemia Research Articles

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.

Successful Treatment of Severe Aplastic Anemia with Hematopoietic Stem Cell Transplantation in the Setting of Active Mucormycosis

Successful Treatment of Severe Aplastic Anemia with Hematopoietic Stem Cell Transplantation in the Setting of Active Mucormycosis

The role of TIM3+ NK and TIM3- NK cells in the immune pathogenesis of severe aplastic anemia.

Natural killer (NK) cells play important immunoregulatory roles in the immune pathogenesis of severe aplastic anemia (SAA). Our previous research showed that SAA caused a decrease in T cell immunoglobulin mucin-3 (TIM3) expression on NK cells. Here we investigated the expression of surface receptors, and the cytotoxicity of peripheral TIM3+ NK and TIM3- NK cells in patients with SAA. The expressions of surface receptors and cytoplasmic protein of TIM3+ NK and TIM3- NK cells from peripheral blood were detected by FCM. The functions of mDCs, and apoptosis rate of K562 cells after co-culture with TIM3+ NK and TIM3- NK cells were maesured by FCM. Westren-blot was used to detect the changes of TIM3+ NK and TIM3- NK signaling pathway proteins (AKT, P-AKT) and compare the functional activity of the two groups. Activating receptors NKG2D and Granzyme B were higher, while inhibiting receptors NKG2A, CD158a and CD158b were lower on TIM3- NK cells compared with TIM3+ NK cells in patients with SAA. In SAA, the expression of CD80 and CD86 on mDCs (Myeloid dendritic cells) was significantly decreased after incubation with TIM3- NK cells. The apoptosis rate (AR) of K562 cells was significantly increased after being incubated with TIM3- NK cells in SAA. The level of signal pathway protein AKT of TIM3- NK cells in SAA was similar to that of TIM3+ NK cells, and the levels of P-AKT and P-AKT/AKT ratio of TIM3- NK cells were significantly higher than those of TIM3+ NK cells. Therefore, TIM3 exerts its inhibitory effect on NK cells and participates in the immune pathogenesis of SAA. Low expression of TIM3 contributes to the enhancement of NK cell activity which in turn inhibits the immune activation state of SAA and improves the disease state. Our research may aid the development of new therapeutic strategies based on TIM3-NK cells infusion for the treatment of SAA.

Impurity assessment, development and validation of an RP-HPLC method for the determination of eleven potential impurities of eltrombopag precursor

Eltrombopag is an oral non-peptide thrombopoietin receptor (TPO-R) agonist indicated for the treatment of thrombocytopenia in patients with persistent or chronic immune thrombocytopenia (idiopathic thrombocytopenic purpura, ITP) or chronic hepatitis C infection and the treatment of severe aplastic anemia. The purpose of this research was to assess the possible impurities that may carry over to eltrombopag from its precursor Eltro-1 (3′-amino-2′-hydroxy-[1,1′-biphenyl]-3-carboxylic acid) and to develop a specific analytical method for the determination of these impurities. Eltro-1 samples synthesized by two different synthesis routes were investigated during the evaluation and method development studies. Besides the expected process-related impurities (Eltro-1A – Eltro‐1J), e.g., starting materials, intermediates, and/or compounds formed from their further reactions, an unknown impurity detected above 0.10% was identified by LC-MS, synthesized and fully characterized by NMR, MS and FTIR (Eltro‐1K). Accordingly, an HPLC-RP method for the determination of eleven impurities (Eltro-1A – Eltro‐1K) in Eltro-1 was developed and validated according to ICH Q2. The control limits for impurities in Eltro-1 were set at ≤ 0.15% for Eltro-1A – Eltro‐1J and ≤ 1.0% for Eltro‐1K based on fate, spike-purge and carryover studies and in accordance with the ICH M7 classification for impurities in drug substance. Eltro-1 and eleven impurities at the specification limit were separated from each other and the diluent peaks with sufficient resolution without interference. Separation was performed on a Waters XBridge C18 column (150 × 4.6 mm, 3.5 μm) at 40 °C with a 10 µL injection volume at a detection wavelength of 220 nm and 15 °C sample temperature. The gradient elution is performed at a flow rate of 1.0 mL/min for 40 min with mobile phase A (0.1% orthophosphoric acid in water) and B (acetonitrile) according to the following program: Time (min) / Acetonitrile (%): 0/0, 35/70, 36/0, 40/0. Test and standard solutions were prepared at a concentration of 1.0 mg/mL and 1.0 µg/mL, respectively, using a mixture of mobile phase A and acetonitrile (75/25) as diluent. This is the first specific, selective, sensitive, linear, precise, accurate, and robust HPLC method for the determination of Eltro-1A – Eltro‐1K in Eltro-1, which showed no significant degradation under thermal stress, photostability (UV and VIS), and standard accelerated and long-term stability conditions.

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

BackgroundThe 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.MethodsWe 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).ConclusionOur 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.

Activity and safety of eltrombopag in combination with cyclosporin A as first‑line treatment of adults with severe aplastic anaemia (SOAR): a phase 2, single-arm study

Antithymocyte globulin (ATG)-based immunosuppression is standard in front-line treatment for people with severe aplastic anaemia without a histocompatible donor or who are 40 years or older. However, ATG requires in-hospital administration, is associated with infusion-related toxicities and has limited availability worldwide. In this study, we investigated the activity and safety of an ATG-free regimen of eltrombopag with cyclosporin A as a potential treatment for patients with severe aplastic anaemia who might not have access to or cannot tolerate horse-ATG. SOAR was a multicentre, single-arm phase 2 trial investigating eltrombopag and cyclosporin in adult (≥18 years) patients with severe aplastic anaemia who were treatment-naive and had an Eastern Cooperative Oncology Group performance status of less than 2. Participants were recruited from 20 hospitals in ten countries. Eltrombopag was initiated at 150 mg (100 mg in patients of Asian ethnicity) and cyclosporin at 10 mg/kg per day (adjusted to a trough of 200-400 μg/L) orally from day 1 to 6 months. The primary outcome was an overall haematological response rate by 6 months in the intention-to-treat population. This is the final report of the primary analysis period. The trial was registered with ClinicalTrials.gov, NCT02998645, and has been completed. 54 patients were enrolled between May 11, 2017, and March 23, 2020. 34 (63%) patients were male and 20 (37%) were female. 22 (41%) were Asian, 22 (41%) were White, one (2%) was Native American or Alaska Native, one (2%) was Black or African American, and eight (15%) were other race or ethnicity. 35 patients (65%) completed 6 months of treatment with eltrombopag and cyclosporin and six (11%) completed the cyclosporin tapering period up to month 24. Overall haematological response rate by month 6 of treatment was 46% (25 of 54; 95% CI 33-60). The most reported adverse events were increased serum bilirubin (in 22 patients [41%]), nausea (16 [30%]), increased alanine aminotransferase concentration (12 [22%]), and diarrhoea (12 [22%]). Eight patients died on-treatment, but no deaths were considered related to the treatment. Eltrombopag and cyclosporin was active as front-line treatment of severe aplastic anaemia, with no unexpected safety concerns. This approach might be beneficial where horse-ATG is not available or not tolerated. Novartis Pharmaceuticals.

Single non-blood-related umbilical cord blood transplantation using a reduced-intensity conditioning regimen for the treatment of severe aplastic anemia

Objective: To evaluated the clinical efficacy of a reduced-intensity preconditioning regimen for single non-blood-related umbilical cord blood transplantation (sUCBT) in the treatment of severe aplastic anemia (SAA) . Methods: The clinical data of 63 patients with SAA who underwent sUCBT from January 2021 to July 2023 at the Department of Hematology of the First Affiliated Hospital of USTC were retrospectively analyzed. Fifty-two patients received total body irradiation/total bone marrow irradiation (TMI) combined with fludarabine or a cyclophosphamide- conditioning regimen (non-rATG group) , while 11 patients received rabbit anti-human thymocyte immunoglobulin (rATG) combined with TMI, fludarabine, or the cyclophosphamide-conditioning regimen (rATG group) . All patients received cyclosporine A and mycophenolate mofetil for graft-versus-host disease (GVHD) prophylaxis. Complications post-transplantation and long-term survival were compared between the two groups. Results: The baseline parameters were balanced between the two groups (P>0.05) . In the rATG group, all patients achieved stem cell engraftment, and in the non-rATG group, five patients had primary graft failure. There was no significant difference in the cumulative incidence of neutrophil engraftment at 42 days after transplantation or platelet engraftment at 60 days between the two groups. The incidence of grade Ⅱ-Ⅳ acute GVHD in the rATG group was significantly lower than in the non-rATG group (10.0% vs. 46.2% , P=0.032) , and the differences in the cumulative incidences of grade Ⅲ/Ⅳ acute GVHD and 1-year chronic GVHD were not statistically significant (P=0.367 and P=0.053, respectively) . There were no significant differences in the incidences of pre-engraftment syndrome, bacterial bloodstream infections, cytomegalovirus viremia, or hemorrhagic cystitis between the two groups (P>0.05 for all) . The median follow-up time for surviving patients was 536 (61-993) days, and the 1-year transplantation related mortality (TRM) of all patients after transplantation was 13.0% (95% CI 6.7% -24.3% ) . Among the patients in the non-rATG and rATG groups, 15.5% (95% CI 8.1% -28.6% ) and 0% (P=0.189) , respectively, had mutations. The 1-year overall survival (OS) rate of all patients after transplantation was 87.0% (95% CI 75.7% -93.3% ) . The 1-year OS rates in the rATG group and non-rATG group after transplantation were 100% and 84.5% , respectively (95% CI 71.4% -91.9% ) (P=0.198) . Conclusion: The preliminary results of sUCBT with a low-dose irradiation-based reduced-intensity conditioning regimen with fludarabine/cyclophosphamide for the treatment of patients with SAA showed good efficacy. Early application of low-dose rATG can reduce the incidence of acute GVHD after transplantation without increasing the risk of implantation failure or infection.

Plain language summary of RACE study results: addition of eltrombopag to standard treatment of severe aplastic anemia.

Severe aplastic anemia (SAA) and very severe aplastic anemia (vSAA) are blood diseases of the bone marrow. If a suitable donor for bone marrow transplant as initial treatment is unavailable, standard immunosuppression is used. Standard immunosuppression treatment includes horse antithymocyte globulin (hATG) and cyclosporin A (CsA). This summary investigated the results of standard immunosuppression treatment (Group A) versus standard immunosuppression treatment with a medication called eltrombopag (Group B) in participants with SAA and vSAA. Eltrombopag is a medicine that improves the blood platelet level and is taken by mouth (orally). Compared to Group A, more participants in Group B showed increased blood cell level to a normal range without SAA or vSAA and faster treatment response. Side effects were similar in both groups even with the addition of eltrombopag for Group B. Participants in both groups reported feeling well after 6, 12 and 24months. Differences in the participant-reported scores (overall health, physical, emotional, and social) between Group A and Group B were minimal. Immunosuppression treatment (hATG plus CsA) with eltrombopag benefited participants with SAA and vSAA and could be the new standard for SAA in persons who cannot undergo bone marrow transplant. At this time, eltrombopag is only approved in specific countries to treat the condition under study that is discussed in this summary. Clinical Trial Registration: NCT02099747 (RACE study).

IST Combined with Full-Dose Rhtpo in the Treatment of Severe Aplastic Anemia -a Prospective Single-Center Clinical Study

BACKGROUND: Immunosuppressive therapy (IST) (anti-thymocyte immunoglobulin (ATG) and cyclosporine (CSA)) is the treatment of choice for patients with acquired severe aplastic anemia (SAA) who are ineligible for hematopoietic stem cell transplantation (HSCT), which results in a hematological response (HR) in about 60-70% of SAA patients, while 1/3 of patients fail to achieve a hematological response. TPO is a hepatic-secreted hematopoietic growth factor that specifically regulates platelet production, induces hematopoietic stem cell differentiation to megakaryocytes by binding to the TPO receptor (MPL), stimulates megakaryocyte proliferation and differentiation, and promotes platelet production and release. Previous retrospective studies have demonstrated that IST combined with rhTPO improves the early hematologic response in SAA patients, but efficacy reported by centers varied depending on the dose and duration of rhTPO. There are no prospective studies of rhTPO application in SAA to confirm its efficacy. So this study was designed to observe the early feeicacy and safety of the SAA patients who were treated with IST combination with full-dose rhTPO. METHODS: This study was a single-center, single-arm, prospective cohort clinical study, enrolling 33 naive SAA patients aged between 14-70 years who diagnosed after April 2021 in our study center. The patients treated with IST combined with full-dose rhTPO (300U/kg.d) for 8 weeks starting from the first day of ATG. The primary endpoint of the observational study protocol good response rate, blood product transfusion volume and safety profile at 3 months of treatment of initial SAA. The patients were also evaluated for total hematologic response rate and adverse effects of drug application, clonal shift rate, and recurrence rate at 3 and 6 months after treatment. Efficacy Criteria：Complete response (CR): HGB>100 g/L, PLT> 100×10 9/L and ANC>1.5×10 9/L; ② Good partial response (GPR): HGB>80g/L, PLT> 50×10 9/L and ANC>1.0×10 9/L; ③ Partial response (PR): withdrawal from blood product transfusion dependence (HGB>70g/L, PLT> 20×10 9/L), hematologic tests improved and no longer met the SAA criteria, but blood count did not meet the GPR criteria. ④No response to treatment (NR): Continuous transfusion dependency was classified as no response. and/or blood count still met SAA criteria. We defined CR+GPR+PR as HR and CR+GPR as good HR. RESULTS: The rhTPO group enrolled 33 patients, and the control group was 99 patients who applied the caliper value of 0.2 to match the previous unapplied TPO treatment of SAA. At 3 months after IST treatment efficacy, the HR rate of 33 patients in the rhTPO group was 66.67% (22 /33 ), and the rate of good HR was 36.4% (12/33). The HR rate in the control group was 32.32% (32 /99 ), and the rate of good HR was 12.12% (12/99). The HR rate and the good HR rate between the two group were significantly statistical differences (66.67% v 32.32%; 36.4% v 12.12%), (P value=0.001; 0.002). At 6 months after IST treatment, the HR rate and good HR rate in the rhTPO group had a significantly higher than those of the control group (66.67% v 32.32%; 36.4% v 12.12%), (P value=0.001; 0.002). No disease transformation such as myelofibrosis, myelodysplastic syndrome and acute myeloid leukemia occurred in all enrolled patients during the follow-up period. CONCLUSION: 22 of the 33 SAA patients in this study achieved HR at 3 months after IST treatment, including 36.4% cases achived good HR , which is the highest good efficacy response in a prospective study of SAA patients in China known to us to date. This confirms that full-dose rhTPO, as a macromolecular peptide, can also promote the recovery of bone marrow hematopoietic function, significantly improved the rapidity and strength of HR in SAA patients. And its clinical effect is no less than that of the various TPO-Ras that have been widely used so far, and may even be higher. 【Keywords】severe aplastic anemia; recombinant human thrombopoietin; immunosuppression treatment.

Incidence and outcomes of subsequent malignancy after allogeneic hematopoietic stem cell transplantation in adult patients with severe aplastic anemia

The allogeneic hematopoietic stem cell transplantation (HSCT) is widely performed for the curative treatment of severe aplastic anemia (SAA). After HSCT, the long-term survival rates of SAA patients have substantially improved, with reported over 80%. However, as the post-HSCT survival period extends, there is a risk of exposure to long-term complications associated with HSCT. One such complication is the development of subsequent malignancies (SNs), which has observed to occur 2-5 times more frequently in HSCT recipients compared to age-matched controls. Although SN can have a critical impact on the survival of patients with SAA post-HSCT, there has been a lack of large-scale, long-term observational studies on the occurrence of SNs after HSCT in a disease of SAA. In this background, we investigated the incidence of SNs after HSCT in adult patients with SAA. This study is a single-center retrospective cohort study conducted on adult patients with SAA who received HSCT from 2002 to 2021. We analyzed the frequency of SN that occurred after HSCT, and the SN types were denominated according to the Surveillance, Epidemiology, and End Results (SEER) database classification. In addition, the cumulative incidence of SNs were analyzed considering death as a competing risk, and the risk factors influencing the occurrence of SN after HSCT were examined using the Fine-Gray model. Total 376 patients were included, and their median age at the time of HSCT was 35 (interquartile range, IQR: 27-46). Of them, 52.9% had received immunosuppressive treatment (ATG+CsA or CsA) before HSCT. HLA-matched sibling, unrelated, haplo-identical donors compromised of 48.7%, 31.6%, and 19.7%, respectively. During the observation period, 30 cases (7.2%) of SN were observed. one patient diagnosed with primary malignancies three times, and another patient having two primary malignancies. Among subsequent malignancies, 33.3% were hematologic malignancies, and 66.7% were solid malignancies. The frequencies of hematologic malignancies were as follows: Post-transplant lymphoproliferative disorder (23.3%), myelodysplastic neoplasm (6.7%), and acute myeloid leukemia (3.3%). The most common solid malignancies were thyroid cancer (26.7%), followed by stomach cancer (13.3%), oral cavity & pharyngeal cancer (10.0%), esophageal cancer (6.7%), bladder cancer, skin cancer, and cervical cancer (3.3% of each). The 15-year cumulative incidence of all malignancies was 13.4% (95% confidence interval [CI]: 7.3%-23.9%) (Figure A). After SN diagnosis, the overall survival rate from the diagnosis of SN (n=27) was 72.3% (95% CI: 55.0%-95.2%) at 12 years (Figure B). The 15-year post-HSCT survival rate for SN patients from the date of HSCT was 74.6% (95% CI: 85.6%-94.9%), which was significantly lower than the survival rate of patients who did not develop SN (n=334, 92.4% [95% CI: 89.6-95.2]) (Log-rank test p = 0.03). Factors identified to have significant impact to the occurrence of SN were the use of Total body irradiation (HR 7.58 [95% CI: 1.07-53.83]) and ATG usage of more than 5mg/kg (HR 7.97 [95% CI: 1.22-52.23]) during HSCT (Table A). We observed occurrences of SN in a considerable proportion of SAA patients after HSCT. Our finding highlights that SN adversely affects survival, and the use of TBI and high dose of ATG were found to be significantly associated with SN occurrence. Therefore, SAA patients having these factors during conditioning regimen should be carefully monitored after HSCT.

Comparison between Hetrombopag and Eltrombopag Combined with IST As First-Line Treatment for Severe Aplastic Anemia

Idiopathic aplastic anemia is a primary bone marrow failure disease that manifests with pancytopenia. Standard IST combined with eltrombopag (EPAG) is recommended as a first-line regimen for severe aplastic anemia patients who are ineligible for HSCT. HPAG is also a small molecule non-peptide TPO-RA developed in China, and the preclinical experiments have demonstrated that hetrombopag (HPAG) can promote the proliferation and differentiation of hematopoietic stem cells and the strength of stimulation was superior to eltrombopag. HPAG also can achieve hematological response for over 40% of IST-refractory SAA patients, and it was approved for use in IST-refractory SAA patients in China in 2021. Our previous report showed that as a first-line treatment, it could improve the HR and CR rate of SAA patients by 68.7% and 34.4% within 6 months, but there has yet to be a report on its efficacy compared to EPAG. Therefore, this study aims to evaluate the difference in early treatment efficacy of SAA patients with HPAG/EPAG combined with IST as first-line therapy. A total of 109 patients were included in this study, with a median age of 38 years, 53 male and 56 female. Among them, 67 patients received treatment with HPAG combined with ATG+CSA, and 42 patients received treatment with EPAG combined with ATG+CSA. The median follow-up time for the HPAG group was 13.7 (8.1-19.6) months, with a median usage duration of 12 (9.4-14.5) months. For the EPAG group, the median follow-up time was 22.5 (9.9-30.5) months, with a median usage duration of 13.5 (7.8-18.7) months. At 3 months, 34 (50.7%) cases in the HPAG group achieved HR, including 9 (13.4%) CR. In the EPAG group, 21 (50%) cases achieved HR, including 5 (11.9%) CR. The HR rates in the HPAG group after 3 months of IST were similar to those in the EPAG group, with no statistically significant difference ( P=0.973). At 6 months, there were no differences in HR and CR between the HPAG and EPAG groups, 65.6% vs 73.8% and 31.3% vs 28.6%, respectively ( P=0.494 and 0.452). The median time to first response in the HPAG group was similar to the EPAG group [3.7 (95% CI: 3.1-6) months vs 3.5 (95% CI: 3.2-6) months, P=0.79]. We further compared the efficacy of TPO-RA combined with IST in patients with different severity of disease. The results showed that the HR and CR of patients with VSAA at 3 and 6 months in the HPAG group were no different compared to that in the EPAG group (HR at 3 and 6 months, 22.2% vs 35.7% and 33.3% vs 57.1%, P=0.671 and 0.404, respectively; CR at 3 and 6 months, 11.1% vs 14.3% and 16.7% vs 28.6%, P=1.000 and 1.000, respectively). In the patients with SAA, the HR, and CR at 3 and 6 months in the HPAG group were comparable to that in the EPAG group (HR, 61.2% vs 57.1% and 77.6% vs 82.1%, P=0.883 and 0.557, respectively; CR, 14.3% vs 10.7% vs 36.7% vs 28.6%, P=1.000 and 0.486, respectively). In the multivariable analysis, for all 109 patients, the acquisition of HR at 6 months was unrelated to TPO-RA types, and positively correlated with higher HGB and PLT levels and PNH positivity, while negatively correlated with disease severity and ALC levels. Baseline PLT levels were the only predictive factor for EPAG group patients to achieve HR 6 months after IST. The acquisition of HR in HPAG group patients after IST was negatively correlated with disease severity and ALC levels, and positively correlated with baseline PNH positivity. Overall, both HPAG and EPAG have good safety profiles, and no patients discontinued treatment due to adverse drug reactions. Abnormal liver function is a concern for both drugs and changes in the main liver function indicators (AST, ALT, DBIL, IBIL) at 3 and 6 months after IST. Among them, significant increases in indirect bilirubin levels were observed in patients using EPAG at 3 and 6 months ( P<0.001), while no significant increases in indirect bilirubin levels were observed in the HPAG group. Overall, HPAG added to standard IST can provide SAA patients with similar efficacy to EPAG, while achieving deeper and faster hematological responses. Moreover, the hepatic safety of HAPG may be superior to EPAG. However, this study is a retrospective study with a small number of cases, and large-scale prospective clinical studies are still needed to verify the results.

Avatrombopag Is Effective in First-Line Treatment of Severe Aplastic Anemia: Early Outcomes of a Prospective Study

Acquired severe aplastic anemia (SAA) is a life-threatening bone marrow failure disease and its pathogenesis involves T cell-mediated autoimmunity. Antithymocyte globulin (ATG) and cyclosporine based immunosuppressive therapy (IST) is effective for patients not eligible for hematopoietic stem cell transplant, and the response rate is 60-70%. Complete hematological response (CR) predicts better survival of patients received IST treatment, but only a few patients achieve CR within 6 months (5% at 3 months and 12-17% at 6 months). Thrombopoietin receptor agonist (TPO-RA) eltrombopag improves the overall response (OR) rate and CR rate of SAA patients when combined with IST, but its hepatotoxicity is still worrying. Avatrombopag is another small-molecule TPO-RA without hepatic toxicity. We previously found that SAA patients received avatrombopag and IST as first-line treatment showed both higher CR rate and OR rate at 3 and 6 months. To validate our findings, a prospective, single-arm study of avatrombopag and IST for newly diagnosed SAA was carried out (NCT05720234). There were 25 patients enrolled in the study by June 31, 2023, including 21 SAA patients and 4 very severe aplastic anemia patients. Patients were diagnosed as AA within 6 months and received ATG, cyclosporine and avatrombopag as first-line treatment. Avatrombopag was administered at the first day of ATG initiation at dose of 60mg per day for patients weight ≥ 50kg and 40mg per day for patients weight < 50kg. ATG was given for 5 consecutive days. Cyclosporine was given orally at dose of 3.5-5mg/kg.d. There were 15 males and 10 males, at a median age of 37 years old. Eighteen patients achieved the end-point of 3 months and 10 patients achieved end-point of 6 months. There were 15 patients achieved hematologic response at 3 months (83.3%), including 5 complete responders (27.8%) and 10 partial responders. The overall response rate at 6 months was 80%, and CR rate was 60%. One patient evolved to hemolytic paroxysmal nocturnal hemoglobinuria at 3 months, with normal count of platelet and white blood cell. In conclusion, the addition of avatrombopag to IST as first-line treatment showed earlier hematologic response and higher complete response rate for patients with SAA.

Efficacy and Safety of Recombinant Thrombopoietin Combined with Immunosuppressive Therapy for Primary Treatment of Severe Aplastic Anemia: A Single-Center, Open-Label, Randomized, Clinical Trial

Standard immunosuppressive therapy (IST) combined with eltrombopag is the first-line treatment regimen for severe aplastic anemia patients who are ineligible for allo-hematopoietic stem cell transplantation (allo-HSCT). However, there was no second-generation TPO receptor agonist available in China before 2019, and only a first-generation TPO preparation was available for clinical treatment. Although rhTPO and eltrombopag act on different receptor binding sites, the differentiation pathways are similar, so rhTPO can theoretically also stimulate hematopoietic stem cells and promote hematopoietic recovery in AA. In 2015, we used rhTPO combined with IST as the first-line treatment for SAA. The results showed that the OR and quality of response in the rhTPO group were significantly higher than those in the control group. Multivariate analysis showed that the application of rhTPO was an independent prognostic factor affecting the efficacy of IST. Based on these results, we performed a single-center, randomized, open-label, parallel-controlled clinical trial to assess the hematologic response rate and long-term safety 3, 6, and 12 months after treatment. The study was conducted between 2015 and 2019 with 188 patients with primary SAA who were randomly assigned to the control or rhTPO group (95 with IST alone and 93 with rhTPO). For rhTPO, 15000 IU was administered subcutaneously starting on day 14 after p-ATG administration and then once every other day for a total of 14 injections. The median age of the 93 patients in the rhTPO group was 33 years (range 16-67). These included 58 patients with SAA and 35 patients with very severe aplastic anemia (VSAA), which were comparable to the control group. There were no significant differences in baseline clinical parameters between groups. No significant differences were observed in the overall hematologic response rates at 3, 6, and 12 months between the rhTPO and control groups (3 months: 40.9% vs 41.1%, P = 0.979; 6 months: 52.7% vs 52.6%, P = 0.994; 12 months: 65.6% vs 63.2%, P = 0.782, respectively). The median time of platelet transfusion independent was 49 (0-376) days in the rh-TPO group and 47 (0-195) days in the control group, which was not different between the two groups ( P = 0.757). The median time of RBC transfusion independence was 47 (5-404) days and 49 (0-295) days, respectively ( P = 0.592). The median follow-up time was 64 (1.3-86.2) months. The 5-year overall survival was 86.4% (95% confidence interval [CI], 77.2-92.0%) in the rh-TPO group and 84.1% (95% CI, 74.5-90.3%, P = 0.898) in the control group. The 5-year event-free survival was 51.7% (95% CI, 41.0-61.5%) and 54.1% (95% CI, 43.5-63.6%, P = 0.947) in the two groups, respectively. No significant differences were observed in the relapse rate and clonal evolution rate between the two groups (11.5% vs. 11.7%, 4.3% vs.3.2%, repectively). Subcutaneous rhTPO injection was well tolerated by patients, with no significant adverse effects other than mild localized pain at the injection site. The patients in the rhTPO group did not have concomitant thrombotic or embolic complications; moreover, reticulo-fibrillary or collagen fibrillary hyperplasia in bone marrow was not detected in any patients at three and six months after IST. Ten patients had anti-TPO antibodies at the end of TPO treatment, with no positive anti-TPO antibodies. In conclusion, our study is the only prospective randomized controlled clinical trial in China of rhTPO combined with IST for the treatment of SAA, with no difference in the hematologic response rate of the 28-day rhTPO combination regimen compared to standard IST; however, we did confirm the safety of rhTPO at this dose. Further clinical studies are required to determine the most effective dosage and duration of rhTPO treatment.

Early Efficacy of IST in Combination with Hetrombopag and Rhtpo As First-Line Treatment for Naïve Severe Aplastic Anemia

BACKGROUND: Immunosuppressive therapy (IST) (anti-thymocyte immunoglobulin (ATG) and cyclosporine (CSA)) is the treatment of choice for patients with acquired severe aplastic anemia (SAA) who are ineligible for hematopoietic stem cell transplantation (HSCT), which results in a hematological response (HR) in about 60-70% of SAA patients. TPO is a hepatic-secreted hematopoietic growth factor that specifically regulates platelet production, induces hematopoietic stem cell differentiation to megakaryocytes by binding to the TPO receptor (MPL), stimulates megakaryocyte proliferation and differentiation, and promotes platelet production and release. Several previous studies have shown that IST combined with rhTPO or hetrombopag can improve the early hematologic response of SAA patients, especially the proportion of good hematologic response (good HR) in the early stage. RhTPO and TPORA have different binding sites with thrombopoietin receptor (c-MPL) and do not have competitive binding, which may produce synergistic effect. A retrospective study showed that eltrombopag combined with rhTPO increased the IST HR and improved the quality of hematologic remission in SAA with mild adverse effects. Therefore the combination of TPORA and rhTPO in SAA patients undergoing IST treatment may result in faster and higher HR rates. Clinical studies have confirmed that hetrombopag, act similarly to eltrombopag in SAA, but there are no clinical studies of hetrombopag in combination with rhTPO in SAA. OBJECTIVE: To evaluate the early-efficacy and safety profile of IST in combination with hetrombopag, and rhTPO in patients with primary, severe aplastic anemia. METHODS: This study was designed for patients with primary aplastic anemia major aged 14-70 years after January 2023 from a single center. This group were planned to be get treat of IST combination with rhTPO 15000U/d for 8 weeks from the first day of ATG and hetrombopag 15mg/d for at least 6 months. The primary endpoint was to observe the good response rate, blood product transfusion and safety profile of the study regimen for the treatment of primary SAA for 3 months. Efficacy Criteria：Complete response (CR): HGB>100 g/L, PLT> 100×10 9/L and ANC>1.5×10 9/L; ② Good partial response (GPR): HGB>80g/L, PLT> 50×10 9/L and ANC>1.0×10 9/L; ③ Partial response (PR): withdrawal from blood product transfusion dependence (HGB>70g/L, PLT> 20×10 9/L), hematologic tests improved and no longer met the SAA criteria, but blood count did not meet the GPR criteria. ④No response to treatment (NR): Continuous transfusion dependency was classified as no response. and/or blood count still met SAA criteria. We defined CR+GPR+PR as HR and CR+GPR as good HR. RESULTS: The trial group proposes to enroll 39 patients and currently includes 8 patients who can be evaluated for 3-month efficacy of IST treatment. And the control group includes two groups of IST combined rhTPO group and IST combined HPAG group in our previous center, and the cohort study of the results of the three groups. In this study, the HR rate of 8 patients can be assessed at present as 75% (6/8), and the rate of good HR was 50% (4/8). The HR of 33 patients in the control IST+rhTPO group was 66.67% (22/33), and the rate of good HR was 36.4% (12/33); the HR rate of 32 patients in the control IST+HPAG group was 46.9% (15/32), and the rate of good HR was 21.9%. The HR rate and good HR rate of the trial group were higher than those of the IST+rhTPO group and the IST+HPAG group (75%v66.67%v46.9%; 50%v36.4%v21.9%). None of the 8 patients enrolled in the trial group had any transformation of myelofibrosis, myelodysplastic syndrome and acute myeloid leukemia during the follow-up period. CONCLUSION: HR was obtained at 3 months in 6 of the 8 patients with severe remodeling IST+rhTPO+ hetrombopag in this study, with a good HR rate of 50%, which is the highest good efficacy response we know of in a prospective study of Chinese SAA patients to date. This confirms that rhTPO combined with hetrombopag can synergize the recovery of bone marrow hematopoietic function in SAA patients treated with IST, and its clinical effect is superior to that of various TPO-Ras or rhTPO that have been widely used. It is expected that more cases will be included in the later stages and that better results will be obtained. 【Keywords】severe aplastic anemia; recombinant human thrombopoietin; hetrombopag ; immunosuppression treatment.

Low-dose post-transplant cyclophosphamide with G-CSF/ATG based haploidentical protocol provides favorable outcomes for SAA patients.

Haploidentical hematopoietic stem cell transplantation (haplo-HSCT), as one of the life-saving treatments for severe aplastic anemia (SAA), is widely used because of its great donor availability. Over decades, granulocyte colony-stimulating factor (G-CSF)/antithymocyte globulin (ATG)-based protocol (the so-called Beijing Protocol) has achieved favorable engraftment and survival outcomes. In this study, we modified the conventional Beijing Protocol: the full-dose Cyclophosphamide (Cy) (200 mg/kg in total) was divided into 42.75 mg/kg Cy on day -5 to day -2 and Low dose post-transplant Cy (PTCy) (14.5 mg/kg on days +3 and +4), hoping to reduce the incidence of severe acute graft-versus-host disease (aGVHD) and to guarantee successful and stable engraftment. Here we retrospectively reported and analyzed the data of first 17 patients with SAA who had received haplo-HSCT using this novel regimen between August 2020 and August 2022. The median follow-up was 522 days (range, 138-859 days). No patient developed primary graft failure. Four (23.5%) patients developed grade II bladder toxicity, two (11.8%) patients developed grade II cardiotoxicity. All patients achieved neutrophil and platelet engraftment at median times of 12 days (range, 11-20 days) and14 days (range, 8-36 days). During our follow-up, no patients developed grade III-IV aGVHD. The cumulative incidence of grade II and grade I aGVHD at 100 days was 23.5% (95% CI, 6.8%-49.9%) and 47.1% (95% CI, 23.0%-72.2%). Three patients (17.6%) developed chronic GVHD of skin, mouth, and eyes and all of which were mild. All patients are alive by the end of the follow-up, with a failure-free survival of 100%, which was defined as survival without treatment failures, such as death, graft failure, or relapse rate. The rate of cytomegalovirus (CMV) reactivation was 82.4% (95% CI, 64.3%-100%). The rate of Epstein-Barr virus (EBV) reactivation was 17.6% (95% CI, 3.8%-43.4%). No CMV disease and post-transplantation lymphoproliferative disorder (PTLD) occurred among these patients. In conclusion, the encouraging results of prolonged survival outcomes and reduced incidence of GVHD suggest promising effect of this novel regimen in haplo-HSCT for patients with SAA. Larger-sample prospective clinical trials are needed to confirm the effectiveness of this regimen.

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

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

Clinical analysis of 76 patients with severe aplastic anemia treated with haploid hematopoietic stem cell transplantation

Objective: The purpose of this study is to determine the efficacy of haploidentical donor hematopoietic stem cell transplantation in the treatment of severe aplastic anemia. Methods: The clinical data of 76 patients with severe aplastic anemia (SAA) patients who underwent haplo-HSCT from December 2014 to October 2020 were selectively analyzed. There were 50 males and 26 females with a median age of 16 (3-52) years old. There were 49 SAA-Ⅰ patients, 18 SAA-Ⅱ patients, and 9 patients with hepatitis-associated aplastic anemia. There were 15 cases of bone marrow put together with peripheral blood stem cell transplantation and 61 cases of peripheral blood stem-cell transplantation. Conditioning regimens were Cyclophosphamide (CY) + Fludarabine (Flu) + ATG for 46 patients and Busulfan (Bu) + CY+Flu+ATG for 30 patients. Results: Three patients died during the myelosuppressive phase following transplantation, and 73 patients had a median time of neutrophil engraftment of 12 (9-21) days; in addition to 3 patients who died early, 8 patients did not obtain platelet reconstruction after transplantation, and 65 patients had platelet engraftment with a medium time of 14 (9-90) d. The incidence of primary graft failure was 10.9% and the incidence of secondary graft failure was 5.5%. The incidence of Ⅱ-Ⅳ acute graft-versus-host disease (aGVHD) was 38.4%, the incidence of Ⅲ-Ⅳ aGVHD was 16.4%, the incidence of chronic graft anti-host disease (cGVHD) was 35.8%, and the incidence of extensive cGVHD was 22.4%. The medium follow-up time was 19.5 (1-75) months, the prospective overall survival (OS) for 2 years was (78.6±5.0) %, the failure-free survival (FFS) was (75.9±5.1) %, and the transplant-related mortality was (20.2±4.9) %. Multi-factor analysis revealed that the patient older than 35 years old, Ⅲ/Ⅳ aGVHD, HCT-CI≥3, the pre-transplant ferritin ≥1 500 μg/L, the number of neutrophils >1×10(9)/L at the time of onset were risk factors affecting OS (P=0.008, 0.008, 0.014, 0.004, 0.027) . Patients with graft failure had lower OS and FFS than other patients (P<0.001) . Conclusion: Haplo-HSCT is an effective method for treating SAA in children, adolescents, and young patients, and the occurrence of severe aGVHD and severe infection, as well as graft failure, are the main causes of survival rate. The prevention and treatment of severe aGVHD and infection are essential to improve efficacy.

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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.