Longitudinal clinical and preclinical studies identify hetrombopag as a potent chelator for systemic iron overload

Yufei Zhao; Lingxiao Xing; Baohang Zhang; Wenrui Yang; Xiangrong Hu; Xu Liu; Xiawan Yang; Weiru Liang; Yimeng Shi; Jing Hu; Xiaoxia Li; Rui Kang; Guangxin Peng; Yuan Li; Xiao Hu; Youzhen Xiong; Liping Jing; Weiping Yuan; Sidan Li; Fengkui Zhang; Xin Zhao

doi:10.1002/hem3.70331

. 2026 Mar 9;10(3):e70331. doi: 10.1002/hem3.70331

Longitudinal clinical and preclinical studies identify hetrombopag as a potent chelator for systemic iron overload

Yufei Zhao ^1,^2,^{^{^}}, Lingxiao Xing ^1,^{^{^}}, Baohang Zhang ¹, Wenrui Yang ¹, Xiangrong Hu ¹, Xu Liu ¹, Xiawan Yang ^1,³, Weiru Liang ^1,³, Yimeng Shi ¹, Jing Hu ¹, Xiaoxia Li ¹, Rui Kang ¹, Guangxin Peng ¹, Yuan Li ¹, Xiao Hu ¹, Youzhen Xiong ¹, Liping Jing ¹, Weiping Yuan ¹, Sidan Li ^4,^✉, Fengkui Zhang ^1,^✉, Xin Zhao ^1,^✉

PMCID: PMC12970488 PMID: 41809835

Abstract

Iron overload (IO) is a pathological condition characterized by excessive iron accumulation, leading to systemic functional impairment. It frequently occurs in patients with congenital or acquired anemia, such as aplastic anemia, who require long‐term transfusions. Iron chelation therapy (ICT) is the standard approach for managing transfusion‐related IO. However, the currently available iron chelators are limited by their toxicity and administration challenges. Hetrombopag (HPAG), an oral small‐molecule non‐peptide thrombopoietin receptor agonist (TPO‐RA), has been approved for the treatment of immune thrombocytopenia and aplastic anemia. HPAG contains an iron‐scavenging moiety that functions independently of its TPO‐RA activity; however, its role in ICT has not been clearly defined. In this study, we conducted a longitudinal evaluation of iron burden in clinical cohorts of patients with severe aplastic anemia treated with immunosuppressive therapy alone or in combination with HPAG therapy. Complementary preclinical models mimicking transfusion‐induced IO have been used to elucidate the therapeutic potential and underlying mechanisms. Our findings identified HPAG as a potent iron‐chelating agent with both prophylactic and therapeutic efficacy against systemic IO. Mechanistically, HPAG functions as a potential ferroptosis inhibitor by significantly reducing toxic iron accumulation, suppressing iron‐induced lipid peroxidation at the cellular level, and alleviating systemic complications. These findings advance our understanding of transfusional IO and support the idea that targeting ferroptosis is a novel therapeutic strategy for systemic IO.

INTRODUCTION

Iron overload (IO) is a pathological condition characterized by the excessive accumulation of iron throughout the body, leading to systemic functional disorders. ¹ , ² , ³ It commonly occurs in patients with intractable anemia, including those with aplastic anemia, thalassemia major, myelodysplastic syndromes, sickle cell anemia, and other congenital and acquired anemias, who are dependent on long‐term transfusions. ⁴ Given the extremely limited physiological capacity for iron elimination, these patients inevitably experience a progressive buildup of iron‐induced toxicity in parenchymal tissues, culminating in a range of complications as their condition advances. ⁵ , ⁶

Toxic iron species appear in the plasma as non‐transferrin‐bound iron (NTBI) when reticuloendothelial macrophages, hepatocytes, and transferrin fail to effectively store or transport excess iron. ⁷ , ⁸ , ⁹ NTBI, a heterogeneous iron complex, can be readily taken up as free iron into intracellular labile iron pools (LIPs), and eventually causes ferroptosis. ³ , ¹⁰ , ¹¹ , ¹² , ¹³ , ¹⁴ Ferroptosis is a recently identified form of cell death characterized by the lethal buildup of iron‐dependent lipid peroxides. At the cellular level, excess free ferrous iron (Fe²⁺) is currently believed to induce ferroptosis, which is considered the primary pathological mechanism of transfusional IO, ³ , ¹⁵ , ¹⁶ and can be effectively inhibited by iron chelators. ¹⁷ , ¹⁸ , ¹⁹

Reducing the iron burden is a primary strategy for treating IO, which includes phlebotomy and pharmacological treatments. ¹ , ²⁰ , ²¹ However, patients with severe anemia cannot tolerate phlebotomy, making pharmacological therapy (iron‐binding drugs) the preferred option. ¹⁶ , ²² Traditional iron chelators (deferoxamine, deferiprone [DFP], and deferasirox [DFX]) are effective; however, they are often associated with poor adherence and side effects, such as liver and kidney damage, bone marrow (BM) suppression, and gastrointestinal issues. ²⁰ , ²³ , ²⁴ , ²⁵ , ²⁶ Accumulated iron toxicity can cause organ injury, impair the immune system, and increase the risk of infections and cancer. ²⁷ , ²⁸ , ²⁹ , ³⁰ , ³¹ Toxic‐free iron disrupts the BM microenvironment or directly damages hematopoietic stem and progenitor cells, complicating the treatment of the primary disease. ³² , ³³ , ³⁴ , ³⁵ , ³⁶ Therefore, the development of novel iron chelators with a longer half‐life and fewer side effects, particularly those that do not impair hematopoiesis, is urgently needed.

Hetrombopag (HPAG), a new generation of oral, small‐molecule, non‐peptide thrombopoietin receptor agonist (TPO‐RA), ³⁷ has been approved for the treatment of immune thrombocytopenia (ITP) and severe aplastic anemia (SAA). ³⁸ , ³⁹ , ⁴⁰ , ⁴¹ In SAA, adding HPAG to standard immunosuppressive therapy (IST) as first‐line treatment has been shown to induce faster and better hematologic responses. ⁴² HPAG possesses a potential iron‐chelating effect, with a metal ion scavenging structure, which is presumably independent of its TPO‐RA activity. This was first demonstrated in patients with SAA in a phase II clinical trial, suggesting potential benefits for patients with IO. ⁴³ Despite its potential, research on the iron‐chelating properties of HPAG is limited. Moreover, its regulatory effects on systemic iron metabolism and cellular ferroptosis have not yet been fully elucidated. Notably, the stem cell‐stimulating effects of HPAG as a TPO‐RA, which are specific to humans and primates, may interfere with its effects on hematopoiesis via iron regulation. Hence, IO mice that mimic frequent transfusions are necessary to serve as functionally separated preclinical models for studying the iron‐chelating function of HPAG.

Here, we conducted a comprehensive longitudinal analysis of iron burden in patients with SAA to establish a foundational understanding of the natural course of transfusional IO. Preclinical models have been used to systematically investigate the therapeutic potential and underlying mechanisms of HPAG in systemic IO. The prophylactic and therapeutic efficacies of HPAG have been confirmed in matched clinical cohorts. These findings identify HPAG as a potent iron‐scavenging agent and potential ferroptosis inhibitor, offering new avenues for the treatment of systemic IO.

MATERIALS AND METHODS

Patients

We conducted a retrospective study on the longitudinal iron burden in patients with newly diagnosed SAA treated at the Anemia Therapeutic Centre of our institute. Patients who received standard IST plus HPAG (HPAG cohort) were compared to those treated with IST alone (historical cohort) by propensity score matching (PSM). The study was approved by the Ethical Committee of our institute (IIT2021008‐EC‐1), and informed consent was obtained from all patients.

Hematologic response was classified as complete response (CR), partial response (PR), or no response (NR). CR was defined as an Hb level ≥100 g/L, platelet count ≥100 × 10⁹/L, ANC ≥ 1.5 × 10⁹/L, and independence from transfusions. PR was defined as an Hb level ≥70 g/L, platelet count ≥20 × 10⁹/L, and ANC ≥ 0.5 × 10⁹/L, with transfusion independence, but without meeting the criteria for CR. Responders were defined as patients achieving either PR or CR. NR was defined as the persistence of blood counts that continued to meet the criteria for SAA, with continued transfusion dependence.

Animals

Wild‐type male mice with a C57BL/6 genetic background, aged six to eight weeks, were housed in a specific pathogen‐free facility. All animal experiments were conducted following protocols approved by the Animal Ethics and Welfare Committee of our institute (IHCAMS‐DWLL‐QTJC2022057‐1).

Details on the materials and methods are included in Supplemental Data.

RESULTS

Iron burden in patients with SAA before standard IST treatment and during follow‐up

Patients with SAA frequently develop transfusion‐related IO. ⁴ , ⁴⁴ To gain a basic understanding of the natural trajectories, we first assessed the longitudinal iron burden in a historical cohort of patients with newly diagnosed SAA (n = 312) who received standard IST treatment alone (Figure 1A and Supporting Information S1: Table 1). At baseline, a significant proportion of patients showed an elevated iron burden with poor hematologic response in the following months (Figure 1B,C). Using linear mixed‐effects models, we identified hematological response and disease severity as the most significant factors influencing changes in iron burden over time (Supporting Information S1: Table 2).

Non‐responders showed persistent accumulation of serum ferritin (SF) levels, while serum iron (SI) and transferrin saturation (TSAT) remained consistently higher than those in patients with PR or CR (Figure 1D and Supporting Information S1: Figure 1). Patients with a PR showed a more gradual change in SF, whereas those with a CR showed a decreasing trend (Figure 1D). Patients with very severe aplastic anemia (VSAA) showed a more aggressive increase in SF than those with SAA (Figure 1E). A progressive accumulation of iron burden to clinically significant IO (SF ≥1000 ng/mL in combination with TSAT >50%, a commonly used threshold for considering iron chelation therapy) was observed in most non‐responders (Figure 1F). Secondary IO can negatively affect the primary disease, potentially creating a detrimental cycle that worsens prognosis, emphasizing the urgent need for iron‐chelating therapy (ICT).

Iron‐dependent lipid peroxide accumulation and systemic disorders in transfusional IO

To evaluate novel agents for ICT, preclinical models mimicking transfusional IO were developed and validated using biochemical iron parameters, hematological changes, and clinical features (Figure 2A–C and Supporting Information S1: Figure 2A). ¹ , ³⁵ , ⁴⁵ , ⁴⁶ Compared to healthy controls, IO mice gradually developed brownish‐gray skin and yellow‐brown teeth and demonstrated delayed responsiveness and attenuated weight gain. At the cellular level, free ferrous iron initiates a lipid peroxidation cascade, leading to cell death, which is an essential pathogenic mechanism of systemic IO. The accumulation of iron‐dependent lipid peroxides, such as malondialdehyde (MDA), as observed in preclinical models and patients with SAA (Figure 2D–F and Supporting Information S1: Figure 2C), can induce DNA damage and exacerbate cellular injury.

In patients with intractable anemia, excess labile iron has a critical impact on the hematopoietic and immune microenvironments. Human hematopoietic stem cells (HSCs), but not progenitors, were recently found to be selectively vulnerable to ferroptosis due to low rates of protein synthesis. ⁴⁷ Consistent with this vulnerability, IO mice displayed elevated LIP in BM lineage⁻Sca‐1⁺c‐Kit⁺ (LSK) cells and a concomitant reduction in long‐term HSCs (LT‐HSCs), confirming that free iron toxicity preferentially impairs stem cells (Figure 2G and Supporting Information S1: Figure 2D). Within the immune milieu, T lymphocytes, particularly the CD4⁺ subset, have recently been reported to show sensitivity to ferroptosis. ⁴⁸ , ⁴⁹ Our preclinical data corroborated this finding: IO mice showed a marked decrease in the CD4⁺/CD8⁺ T‐cell ratio in the BM and a reduction in splenic CD3⁺ T‐cells, indicating immunological dysregulation driven by excess iron (Figure 2H and Supporting Information S1: Figure 2E).

Collectively, iron‐dependent lipid peroxidation and systemic disorders were closely related in the setting of transfusional IO, exacerbating the primary disease (Figure 2I). Under these conditions, ICT remains the cornerstone of intervention for interrupting this vicious cycle.

HPAG alleviates systemic IO as a novel iron‐chelating agent, beyond a TPO‐RA

To evaluate HPAG as a novel ICT agent, transfusional IO mice were treated with HPAG, and DFX, a clinically approved iron‐chelating agent, was used as a positive control (Figure 3A,B). HPAG administration markedly ameliorated biochemical iron indices, hematological changes, and clinical features comparable to those observed with DFX (Figure 3C–F; and Supporting Information S1: Figure 3A–B). Furthermore, HPAG substantially reduced histopathological iron deposition in the liver and spleen, as well as in the BM, heart, pancreas, and kidneys, which are highly susceptible to iron toxicity. Concomitantly, HPAG restored extensive damage to the duodenal mucosal integrity and liver fibrosis (Figure 3G and Supporting Information S1: Figure 3C).

Consistent with known iron‐responsive pathways, in IO mice, hepatic IO induced BMP6 expression, activated BMP/SMAD signaling, and promoted transcription of the hepcidin‐encoding gene HAMP. This was accompanied by increased expression of the ferritin heavy and light chain genes (FTH1 and FTL1) and reduced expression of TFRC, which encodes transferrin receptor 1. IO further indirectly influenced the expression of stress‐responsive genes, such as HIF1A and HMOX1. ⁵⁰ , ⁵¹ , ⁵² Following HPAG treatment, similar to DFX, these alterations in iron homeostasis were significantly reversed. In addition, HPAG decreased hepatic and serum MDA levels, indicating alleviation of intracellular iron excess and iron‐driven oxidative stress (Figure 3H–L and Supporting Information S1: Figure 3D).

Furthermore, HPAG considerably decreased LIP levels in BM cells, and more specifically, in the LSK subset (Figure 4A). Notably, as previously reported, ³⁷ the stem cell‐stimulating effect of HPAG as a TPO‐RA is species‐dependent, specific to humans and primates, and was not observed in preclinical models. Consistently, no increase in platelet count or upregulation of the c‐MPL signaling pathway was observed in the liver or BM RNA‐seq data (Supporting Information S1: Figure 4A,B). Overall, HPAG efficiently treated systemic IO, comparable to the clinically available chelators.

**HPAG provides therapeutic benefits in systemic IO**. **(A)** Relative LIP levels in both BM and LSK (Lineage^‐Sca‐1⁺c‐Kit⁺) cells, calculated as the reciprocal of calcein‐AM MFI in IO, HPAG‐treated, DFX‐treated, and healthy control groups (n = 4). **(B)** Schematic of the pathogenesis of transfusional IO at the cellular level and the potential therapeutic strategies. **(C)** Subsets of the BM LSK population were analyzed by flow cytometry, including the proportions of LSK, LT‐HSCs, ST‐HSCs, and MPPs among live BM cells (n = 5). **(D)** Absolute number of BM cells in bilateral tibiae and femurs (n = 5). **(E)** PCA and transcriptional profiles of DEGs derived from RNA sequencing analysis of c‐Kit⁺ BM cells from healthy controls, untreated IO mice, and HPAG‐treated IO mice (n = 3). **(F)** CD4⁺/CD8⁺ T‐cell ratio in the BM (n = 5). **(G)** Quantification of serum IFN‐α and IFN‐γ concentrations (n = 6). **(H)** Percentage of CD3⁺ T cells and the CD4⁺/CD8⁺ T‐cell ratio in the spleen (n = 5). *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001. BIW, biweekly; DEG, differentially expressed gene; i.g., intragastric administration; i.p., intraperitoneal injection; Lin⁻, lineage⁻; MFI, median fluorescence intensity; MPP, multipotent progenitor; PCA, principal component analysis; QD, once daily; SP, spleen. Bars show mean ± SD, unpaired t‐test.

HPAG provides both prophylactic and therapeutic benefits in systemic IO

Ferroptosis is a regulated form of cell death driven by ferrous iron‐dependent peroxidation of membrane polyunsaturated fatty acid‐phospholipids (PUFA–PLs). Theoretically, inhibition of the terminal lipid peroxidation step could attenuate transfusion‐associated IO injury. ¹⁵ , ⁵³ To test this hypothesis, mice with IO were treated with the radical‐trapping antioxidant ferrostatin‐1 (Fer‐1), a specific inhibitor of ferroptosis (Figure 4B). ¹⁹

Flow cytometry analysis revealed that HPAG, DFX, and Fer‐1 mitigated IO‐induced damage to LT‐HSCs. Furthermore, HPAG and DFX markedly increased the number of LSK cells and short‐term HSCs (ST‐HSCs), suggesting stem cell stimulation via iron chelation (Figure 4C–D). In the principal component analysis (PCA) of BM c‐Kit⁺ RNA‐seq data, HPAG‐treated samples clustered with healthy controls and were clearly separated from the IO group. Transcriptome profiling revealed that HPAG substantially reversed IO‐induced alterations (Figure 4E and Supporting Information S1: Figure 4C). In the immune milieu, treatment with HPAG, DFX, or Fer‐1 restored the IO‐induced imbalance in the BM CD4⁺/CD8⁺ T‐cell ratio and inhibited excess IFN‐α and IFN‐γ production, thus ameliorating aberrant immune activation and the associated proinflammatory status (Figure 4F–G and Supporting Information S1: Figure 4D,E). Additionally, Fer‐1 alleviated the suppression of splenic CD3⁺ T‐cells (Figure 4H and Supporting Information S1: Figure 4F). Fer‐1, a well‐established inhibitor of lipid peroxidation, ameliorates IO‐induced abnormalities, supporting the critical role of cellular ferroptosis in systemic IO injury.

Although HPAG did not restore splenic CD3⁺ T cells, it increased the splenic CD4⁺/CD8⁺ T cell ratio, which was not observed after DFX administration (Figure 4H). RNA‐seq data revealed the enrichment of pathways related to the regulation of T cell‐mediated immunity in the HPAG group, indicating a potential immunomodulatory role (Supporting Information S1: Figure 5).

Differential RNA‐seq analyses of the bone marrow and the liver revealed that HPAG treatment enriched gene sets involved in the cell cycle, DNA replication and repair, heme metabolism, and iron homeostasis, while pathways related to T cell death, NF‐κB signaling, and oxidative stress were suppressed compared with untreated IO samples (Figure 5A,B). In addition, metabolic pathways associated with carbohydrate, lipid, and amino acid metabolism were enriched, indicating metabolic recovery and supporting the protective effects of HPAG against iron toxicity. ⁵⁴

**HPAG provides both prophylactic and therapeutic benefits in systemic IO**. **(A)** GSVA of RNA sequencing data from liver and BM c‐Kit⁺ cells, comparing HPAG‐treated and untreated IO mice. **(B)** Pathway enrichment analysis of DEGs up‐ or downregulated in the livers of HPAG‐treated versus untreated IO mice, based on RNA sequencing data. **(C)** MFI of intracellular ferrous iron and representative flow cytometry plots. In rat cardiomyocyte H9C2 cells, co‐incubation with FAC and HPAG for 12 h significantly reduced intracellular ferrous iron (Fe²⁺) levels. **(D)** Experimental schematic of HPAG prophylaxis in IO mice (n = 5). **(E)** Serum iron, serum MDA, and liver MDA were measured in IO, HPAG‐prophylaxis, and healthy control groups (n = 3–5). **(F)** Relative LIP levels in BM LSK cells, proportions of LT‐HSCs among live BM cells, and the CD4⁺/CD8⁺ T‐cell ratio of BM and SP in IO, HPAG‐prophylaxis, and healthy control groups (n = 4–5). BIW, biweekly; DEG, differentially expressed gene; DFP, deferiprone; FAC, ferric ammonium citrate; GSVA, gene set variation analysis; HPAG Pro, HPAG‐prophylaxis; i.g., intragastric administration; i.p., intraperitoneal injection; LSK, lineage⁻ Sca‐1⁺ c‐kit⁺; LT‐HSC, long‐term hematopoietic stem cell; MFI, median fluorescence intensity; MDA, malondialdehyde; QD, once daily; SP, spleen. Bars show mean ± SD, unpaired t‐test.

In addition to the effects on hematopoiesis and immunity, IO can cause fatal cardiac injury. We therefore further evaluated the therapeutic effects of HPAG in rat cardiomyoblast H9C2 cells. Co‐treatment with ferric ammonium citrate (FAC) and HPAG for 12 h significantly reduced intracellular ferrous iron (Fe²⁺) levels, suggesting a potential cardioprotective role of HPAG against IO (Figure 5C).

Given the importance of ICT for patients at risk of IO, we evaluated HPAG prophylactically. In IO mice pretreated with HPAG, systemic iron accumulation was effectively prevented, and both LT‐HSCs and the BM CD4⁺/CD8⁺ T cell ratio were preserved, indicating the prophylactic benefits of HPAG (Figure 5D–F and Supporting Information S1: Figure 6).

Collectively, these findings indicate that HPAG provides both prophylactic and therapeutic benefits for systemic IO.

HPAG ameliorates iron‐dependent lipid peroxidation and shows ferroptosis‐inhibitory effects

Ferroptosis, characterized by phospholipid peroxidation of polyunsaturated fatty acid‐containing phospholipids (PUFA‐PLs) in cellular membranes, can be inhibited by iron‐chelating agents. ¹⁹ , ⁴⁶ , ⁵³ , ⁵⁵ In this study, we identified HPAG as a potent iron chelator with the potential to attenuate lipid peroxidation, thereby functioning as a ferroptosis inhibitor.

Here, we selected the human hepatocellular carcinoma cell line HuH7 to investigate the direct effects of HPAG on ferroptosis. After co‐incubation with FAC and HPAG for 48 h, HPAG significantly reduced the levels of the lipid peroxidation marker BODIPY C11 in HuH7 cells (Figure 6A). In mouse liver tissues, HPAG significantly altered the expression of the antioxidant enzyme glutathione peroxidase 4 (GPX4) and the ferroptosis marker prostaglandin‐endoperoxide synthase 2 (PTGS2) (Figure 6B). Ferroptosis is governed by the balance between local antioxidant defense and iron‐handling systems. Therefore, we focused on tissues rich in GPX4, which are particularly susceptible to IO, including the liver, kidney, and pancreas. IO induced a decrease in GPX4 expression in these tissues, suggesting impairment of the antioxidant system. HPAG administration restored GPX4 levels, similar to DFX, demonstrating protection against ferroptosis‐associated oxidative damage (Figure 6C and Supporting Information S1: Figure 7A).

**HPAG ameliorates iron‐dependent lipid peroxidation and shows ferroptosis‐inhibitory effects**. **(A)** MFI of BODIPY C11 and representative flow cytometry plots. After co‐incubation with FAC and HPAG for 48 h, HPAG significantly reduced the levels of the lipid peroxidation marker BODIPY C11 in HuH7 cells. **(B)** Relative mRNA levels of key ferroptosis‐related genes (including hepatic *GPX4* and *PTGS2* in BM c‐Kit⁺ cells, n = 5) were measured by real‐time qPCR in IO, HPAG‐treated, DFX‐treated, and healthy control groups. Bars show median ± IQR, Mann–Whitney U test. **(C)** Representative IHC images of GPX4 in liver, kidney, and pancreas tissues, along with mean OD analysis. (Scale bars, 50 μm for the kidney and the pancreas; 100 μm for liver) (n = 3). Bars show mean ± SD, unpaired t‐test. (D, E) Lipidomic profiles of PUFA‐PLs and the intensity of representative phospholipids in liver tissues in IO, HPAG‐treated, and healthy control groups (n = 4). Bars show median ± IQR, Mann–Whitney U test. **(F)** Schematic of the therapeutic mechanism of HPAG in systemic IO at the cellular level. *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001. ePL, ether phospholipid; FAC, ferric ammonium citrate; GPX4, glutathione peroxidase 4; IHC, immunohistochemistry; IQR, interquartile range; logFC, log fold change; MFI, median fluorescence intensity; OD, optical density; PA, phosphatidic acid; PC, phosphatidylcholine; PE, phosphatidylethanolamine; PG, phosphatidylglycerol; PI, phosphatidylinositol; PS, phosphatidylserine; PTGS2, prostaglandin‐endoperoxide synthase 2; PUFA‐PLs, polyunsaturated fatty acid–phospholipids.

Furthermore, IO leads to depletion of PUFA‐PLs in the cell membrane as a result of lipid peroxidation. ¹¹ , ⁵⁶ , ⁵⁷ In IO hepatic tissues, lipidomic profiling revealed a pronounced decrease in the abundance of numerous primary substrates for lipid peroxidation, particularly PUFA‐containing phosphatidylethanolamines (PUFA‐PE), PUFA‐containing phosphatidylcholines (PUFA‐PC), and PUFA‐containing ether phospholipids (PUFA‐ePL). HPAG administration reversed these effects, indicating effective protection against ferroptosis (Figure 6D–F and Supporting Information S1: Figure 7B,C).

Overall, these findings demonstrate that HPAG attenuates iron‐dependent lipid peroxidation and shows potent ferroptosis‐inhibitory effects via iron chelation.

HPAG reduces the accumulated iron burden in patients with SAA, providing both prophylactic and therapeutic benefits

To validate our findings in real‐world settings, we conducted a retrospective study on the longitudinal iron status of newly diagnosed SAA patients receiving standard IST combined with HPAG treatment (the HPAG cohort) over a 2‐year follow‐up period. The median duration of HPAG treatment was 21.67 months. Using PSM, patients in the HPAG cohort (n = 60) were matched to a historical cohort of patients (n = 117) who received standard IST alone based on age, disease severity, and hematologic response to minimize potential bias (Figure 7A and Supporting Information S1: Table 3). Linear mixed‐effects models identified HPAG treatment, disease severity, and response status as significant factors influencing changes in iron burden over time (Supporting Information S1: Table 4).

**HPAG reduces the accumulated iron burden in patients with SAA**. **(A)** Schematic representation of the HPAG and matched historical cohorts. Using propensity score matching, newly diagnosed SAA patients who received IST plus HPAG (n = 60) were matched to a historical cohort of patients who received standard IST alone (n = 117), based on disease severity and hematological response. IO cohorts were defined as elevated SF and TSAT. A linear mixed‐effects model was used to assess changes in SF, identifying HPAG treatment, along with disease severity and hematologic response, as significant factors influencing iron burden over time among the HPAG and historical cohorts. **(B)** SF fold‐changes relative to baseline in the HPAG and historical cohorts over the two‐year follow‐up. Bars show median ± IQR, Mann–Whitney U test. **(C)** Longitudinal analysis of SF using linear mixed‐effects models. Significant cohort × time interactions and differences in slope were observed. Results were averaged over the levels of response and severity, with degrees of freedom determined by the Satterthwaite method. (D, E) SI and TSAT fold‐changes relative to baseline over time. **(F)** Cubic spline‐fitted curve of the proportion of patients with Mod/Sev IO over time. Bars show median ± IQR, Mann–Whitney U test. **(G)** Longitudinal analysis of SF using linear mixed‐effects models in responders from the HPAG (n = 37) and historical cohorts (n = 73). **(H)** Bar plot showing iron status for responders at baseline (Pre) and 12 months posttreatment (Post). Chi‐square test. **P < 0.01. IQR, interquartile range; Mod/Sev IO, moderate/severe iron overload; SE, standard error.

Compared to the historical cohort, SF fold‐changes were considerably lower in the HPAG cohort across all patients, as well as within subgroups categorized by iron status at baseline, response, and severity (Figure 7B and Supporting Information S1: Figure 8A–F). Longitudinal analysis showed a steady decline in SF over 2 years in the HPAG cohort, with decreased fold changes in serum iron (SI) and transferrin saturation (TSAT) (Figure 7C–E and Supporting Information S1: Figure 8G–I). The percentage of patients with SF ≥1000 ng/mL, the threshold for initiating ICT, was markedly lower after HPAG treatment (Figure 7F).

Among the responders, HPAG substantially reduced both the iron burden and the proportion of patients with IO (Figure 7G–H). For patients at high risk of developing IO, particularly nonresponders and those with VSAA, the HPAG cohort showed only a mild increase in iron burden over time. In contrast, the historical cohort showed pronounced accumulation (Figure 8A–D). The proportion of patients with moderate‐to‐severe IO (Mod/Sev IO) was considerably lower after HPAG, demonstrating its prophylactic benefit.

**HPAG provides both prophylactic and therapeutic benefits in iron‐chelation therapy for patients with SAA**. **(A)** Longitudinal analysis of SF using linear mixed‐effects models in nonresponders from the HPAG (n = 23) and historical cohorts (n = 44). **(B)** Bar plot showing iron status among nonresponders at baseline (Pre) and 12 months posttreatment (Post). Chi‐square test. **(C)** Longitudinal analysis of SF using linear mixed‐effects models in patients with VSAA. **(D)** Bar plot showing iron status among patients with VSAA at baseline (Pre) and 12 months posttreatment (Post). Chi‐square test. **(E)** Longitudinal analysis of SF using linear mixed‐effects models in patients with baseline IO. **(F)** Line graph illustrating changes in SF concentrations and the fitted curve for ten representative patients with IO at baseline from the HPAG cohort (Up) and their matched individuals in the historical cohort (Down) over time. **(G)** Serum ferrous iron, MDA, and NTBI levels at baseline (Pre) and 12 months posttreatment (Post) in paired patients from the HPAG‐treated IO cohort. Bars show mean ± SD, unpaired t‐test. **(H)** Spearman correlation between serum ferrous iron and MDA levels in the paired patients from the HPAG‐treated IO cohort. **(I)** Schematic depicting the therapeutic mechanism of HPAG in systemic IO. *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001. PUFA‐PL, polyunsaturated fatty acid–phospholipids; SE, standard error.

In patients with IO at baseline, HPAG showed therapeutic benefits, as illustrated by matched representative cases (Figure 8E–F). Consistent with our preclinical results, the serum levels of toxic iron species, such as ferrous iron or NTBI, as well as the lipid peroxidation marker MDA, were significantly reduced at 12 months posttreatment (Figure 8G–H), supporting the potential ferroptosis‐inhibition effect of HPAG.

Collectively, these findings demonstrate that HPAG effectively alleviates the iron burden and mitigates systemic iron toxicity in patients with SAA. In patients with pre‐existing IO or those at risk, HPAG effectively prevented and alleviated secondary IO, providing benefits beyond those of TPO‐RA activity (Figure 8I).

DISCUSSION

Long‐term red blood cell transfusion is currently a routine life‐saving intervention for patients with refractory anemia. Our longitudinal profiling of the iron burden in SAA revealed that a substantial proportion of patients already showed transfusional IO at diagnosis and during follow‐up. Patients with suboptimal responses inevitably achieve clinically significant IO thresholds. Prolonged exposure to excessive iron promotes systemic complications, which adversely affect the quality of life and overall survival. ¹ , ⁵⁸ Importantly, these adverse outcomes are entirely preventable with the timely administration of iron‐chelating agents.

At the cellular level, it was previously understood that iron accumulation primarily led to the generation of reactive oxygen species, resulting in cellular dysfunction and apoptosis. However, the identification of ferroptosis has significantly advanced our understanding of the pathogenic mechanisms underlying systemic IO. ¹¹ Toxic free iron promotes the peroxidation of PUFA‐PLs in the cell membrane, triggering ferroptosis and ultimately resulting in organ injury and systemic dysfunction. Lipid peroxidation products, such as MDA, can induce DNA damage and exacerbate cellular injury. In patients with transfusional IO, we observed that serum ferrous iron (Fe²⁺) and MDA levels correlated with the degree of iron burden, in line with preclinical findings. Moreover, differences in metabolic profiles result in varying sensitivities to ferroptosis among distinct cell types. ⁴⁷ , ⁴⁸ For example, from the perspective of hematopoiesis and immunity, HSCs and T lymphocytes are particularly susceptible to ferroptosis, making them more vulnerable to IO injury, as confirmed by our results. Eventually, IO induces a detrimental cycle that impedes the treatment of the primary disease. ⁵⁹ Notably, toxic iron species can be rapidly and markedly reduced by iron chelators. Thus, the inhibition of the ferroptosis pathway via iron chelation is the principal therapeutic strategy for managing transfusional IO. ⁴⁶ , ⁵³

ICT should be considered in all patients receiving long‐term red blood cell transfusions to prevent potential impairment of hematopoiesis and immune function. ¹⁶ , ²⁶ , ⁶⁰ , ⁶¹ , ⁶² , ⁶³ , ⁶⁴ Ideally, ICT should be initiated prophylactically before the development of systemic complications. ⁴ However, the currently available chelators are limited by toxicity risks and administration challenges. Therefore, agents with longer half‐lives and fewer adverse effects are imperatively required. ²² , ⁶¹ , ⁶⁵

The novel iron‐chelating agent HPAG, a new‐generation TPO‐RA, has been approved for the treatment of ITP and SAA, with an extended half‐life of 23.2–39.8 h. ⁴¹ HPAG is produced by structurally modifying the TPO‐RA eltrombopag (EPAG) to enhance potency and reduce toxicity. ³⁷ Compared with EPAG, the chemical structure of HPAG confers increased lipophilicity and reduced hepatotoxicity, which presumably enhances its iron‐chelating capacity while minimizing adverse effects. Recent results from a phase 3 trial (NCT03825744) indicate that adding HPAG to IST as a first‐line treatment is safe and effective, significantly improving hematologic response in patients with SAA. ⁶⁶ Similar to EPAG, ⁶⁷ HPAG possesses an iron‐scavenging structure beyond its TPO‐RA activity. To elucidate this function, we conducted preclinical studies using transfusional IO mouse models. HPAG effectively reduces excessive iron deposition and ameliorates systemic disorders when administered prophylactically or therapeutically. The mechanism of iron chelation during iron homeostasis is similar to that of DFX. Moreover, among currently available iron chelators, DFP remains a well‐tolerated option and is particularly effective in removing cardiac iron, which is a major cause of mortality in transfusional IO.

We further evaluated HPAG in matched clinical cohorts of patients with SAA. Longitudinal analyses showed that when combined with IST, HPAG considerably alleviated the iron burden in patients with SAA. In patients at risk for IO, HPAG shows prophylactic efficacy, whereas in those presenting with IO at diagnosis, HPAG substantially reduces toxic iron species. In responders with pre‐existing IO, HPAG shortens exposure to iron toxicity, thus reducing the risk of systemic complications. For non‐responders or patients with VSAA who require more frequent transfusions, HPAG slows the build‐up of iron toxicity. Importantly, IO profoundly affects the outcomes of hematopoietic stem cell transplantation (HSCT). ⁶⁸ , ⁶⁹ , ⁷⁰ IO was virtually inexorably in patients who failed to respond to IST. HPAG effectively prevents toxic iron accumulation in these individuals, enabling them to undergo HSCT or other second‐line therapies with a lower iron burden. Therefore, the addition of HPAG to IST alters iron burden trajectories in SAA, providing both preventive and therapeutic benefits. HPAG achieves optimal outcomes in ICT and is expected to improve the prognosis and quality of life of these patients.

Mechanistically, HPAG effectively reduced the levels of toxic free iron, restored the expression of the ferroptosis‐protective enzyme GPX4, and protected membrane PUFA‐PLs from peroxidation in preclinical studies. Compared to the classical ferroptosis inhibitor Fer‐1, HPAG alleviated the detrimental impact on LT‐HSCs and T‐cells and interrupted the vicious cycle driven by iron toxicity. These findings were corroborated by analyses of serum samples from patients with transfusion‐induced IO: after 1 year of HPAG treatment, the levels of serum ferrous iron (Fe²⁺), NTBI, and MDA were markedly reduced. Thus, HPAG ameliorated iron‐dependent lipid peroxidation and showed ferroptosis‐inhibitory effects as a potent iron‐chelating agent.

Notably, in both preclinical studies and clinical cohorts, following HPAG administration, we did not observe an increase in SI as reported during EPAG treatment. ⁷¹ For patients in the HPAG cohort, both SI and SF showed a consistent downward trend over a 2‐year follow‐up period. This discrepancy may be partially attributed to their distinct chemical structures, which confer different solubility characteristics and metabolic profiles in the body. Therefore, the differences in the iron‐chelating mechanisms of HPAG and EPAG need to be clarified in future studies at the cellular level, and the iron‐binding properties of HPAG still remain to be determined.

Targeting ferroptosis is a promising strategy for treating systemic IO. ⁵³ Iron‐dependent phospholipid peroxidation is the central mechanism that drives ferroptosis. Iron chelators block lipid peroxidation and downstream radical generation by chelating labile iron in cytosolic LIPs. Given the central role of iron in ferroptosis, iron chelators are effective inhibitors of ferroptosis. In this study, we identified HPAG as a novel iron chelator with an extended half‐life and fewer adverse effects, thereby expanding the currently limited repertoire of clinical ICT agents.

Nevertheless, among the various ferroptosis inhibitors reported to date, radical‐trapping antioxidants (RTAs) are recognized as the primary strategy for blocking phospholipid peroxidation. ¹⁹ Fer‐1 is a synthetic RTA reported to inhibit ferroptosis. In our study, Fer‐1 alleviated IO‐related disorders, despite not functioning as an iron chelator. Moreover, vitamin E, an endogenous RTA, has been shown to protect HSPCs from ferroptosis. ⁷² Consistently, recent clinical trials have demonstrated that vitamin E supplementation in young patients with transfusion‐dependent thalassemia is associated with decreased MDA levels and enhanced efficacy of DFX in reducing the iron burden. ⁷³ , ⁷⁴ Furthermore, the monounsaturated fatty acid oleic acid has been reported to mitigate IO‐induced injury by inhibiting ferroptosis through alteration of cellular lipid composition. ⁷⁵ Collectively, these studies provide compelling evidence that ferroptosis plays a key pathogenic role in IO‐induced disorders and provides new therapeutic avenues for systemic IO. Further studies on RTAs and other ferroptosis inhibitors in IO are needed, and the potential synergy between RTAs and iron chelators warrants further investigation.

In clinical practice, SF and TSAT remain reliable parameters for assessing iron burden, given the impracticality of routine magnetic resonance imaging (MRI) evaluation and liver biopsy. ⁷⁶ , ⁷⁷ However, these assays do not capture the true iron toxicity driven by ferrous iron or NTBI. The measurement of toxic iron species and lipid peroxidation markers (NTBI, LIP, Fe²⁺, and MDA) is more relevant for evaluating IO‐related tissue damage, but these assays have not yet been validated or standardized for clinical use. This will be an important focus of future studies using prospectively collected fresh serum samples in patients with aplastic anemia. A deeper understanding of iron biology and cellular ferroptosis is required to identify optimal biomarkers that accurately reflect the toxic effects of iron in patients. In addition, large‐scale studies with long‐term follow‐up and more precise quantification of transfusion burden in patients with aplastic anemia are still needed to better delineate the contribution of transfusion exposure to iron toxicity.

In addition to SAA, HPAG has demonstrated favorable efficacy and safety in ITP, ⁴⁰ and has shown preliminary benefits in non‐severe aplastic anemia (NSAA), ⁷⁸ chemotherapy‐induced thrombocytopenia, ⁷⁹ and HSCT‐associated thrombocytopenia or platelet engraftment. ⁸⁰ , ⁸¹ , ⁸² Given its potent iron‐chelating properties, HPAG offers multiple benefits for patients at risk of IO; however, it still needs to be validated in multicenter, large‐scale clinical studies with extended follow‐up across diverse disease settings. In addition, the underlying immunomodulatory mechanisms of HPAG and whether they are mediated by iron‐chelating activities remain to be elucidated.

Particular attention should be paid to the underappreciated risk of iron deficiency, as previously reported with EPAG. ⁷¹ Maintaining a delicate equilibrium between iron deficiency and IO is crucial. Iron deficiency has broader impacts throughout the body, since all mammalian cells, not just red blood cells, require iron. ⁸³ Our study deepens the understanding of ICT in patients and may support more effective management of iron metabolism in the era of iron‐chelating TPO‐RAs.

In summary, by integrating clinical and preclinical studies, we identified HPAG as a potent iron‐chelating agent and potential ferroptosis inhibitor. HPAG effectively reduced toxic iron accumulation, attenuated iron‐dependent lipid peroxidation, and mitigated systemic IO.

AUTHOR CONTRIBUTIONS

Yufei Zhao: Writing—original draft; writing—review and editing; formal analysis; investigation; visualization; methodology; software. Lingxiao Xing: Validation; conceptualization; software; data curation; writing—review and editing; formal analysis; visualization. Baohang Zhang: Investigation; software. Wenrui Yang: Data curation. Xiangrong Hu: Investigation. Xu Liu: Investigation. Xiawan Yang: Investigation. Weiru Liang: Investigation. Yimeng Shi: Investigation. Jing Hu: Investigation. Xiaoxia Li: Investigation. Rui Kang: Investigation. Guangxin Peng: Investigation. Yuan Li: Conceptualization; project administration. Xiao Hu: Methodology; project administration. Youzhen Xiong: Investigation; conceptualization. Liping Jing: Conceptualization; investigation. Weiping Yuan: Resources; funding acquisition. Sidan Li: Data curation; supervision; resources; funding acquisition; project administration. Fengkui Zhang: Funding acquisition; data curation; supervision; resources; project administration; writing—review and editing. Xin Zhao: Project administration; supervision; resources; data curation; funding acquisition; validation; writing—review and editing.

CONFLICT OF INTEREST STATEMENT

The authors declare no conflict of interest.

ETHICS STATEMENT

This study was approved by the Ethical Committee of the Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College (IIT2021008‐EC‐1), and informed consent was obtained from all patients.

All animal experiments were conducted following protocols approved by the Animal Ethics and Welfare Committee of the Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences, and Peking Union Medical College (IHCAMS‐DWLL‐QTJC2022057‐1).

FUNDING

This study was supported by Grant 2022YFA1103300 and 2024YFA1107400 from the National Key R&D Program of China, Grant 2023‐I2M‐C&T‐B‐107 from the Clinical and Translational Medicine Research Project of the Chinese Academy of Medical Sciences, and Grant 82370142 from the National Natural Science Foundation of China.

Supporting information

Supplemental Material_R2.

HEM3-10-e70331-s001.docx^{(7.7MB, docx)}

ACKNOWLEDGMENTS

The authors thank Fudi Wang and Yingying Yu from Zhejiang University (Hangzhou, China) for their valuable support in iron metabolism research. The authors also thank Jiangsu Hengrui Medicine Co. Ltd. (Jiangsu, China) for generously providing Hetrombopag used in this project. The authors are grateful to Lixia Fu, Yaqi Kang, and Quan Gu from the State Key Laboratory of Experimental Hematology, Institute of Hematology & Blood Diseases Hospital (Tianjin, China), for their valuable assistance and support in flow cytometry and omics‐related work. The authors also thank Jumei Shi and Li Zhang from Shanghai East Hospital, Tongji University School of Medicine (Shanghai, China), for their valuable support in manuscript revision and additional experimental work. Parts of the illustrations were created using Figdraw (www.figdraw.com) and are included under license. We would like to thank Editage (www.editage.cn) for English language editing.

Contributor Information

Sidan Li, Email: lisidan2006@126.com.

Fengkui Zhang, Email: fkzhang@ihcams.ac.cn.

Xin Zhao, Email: zhaoxin@ihcams.ac.cn.

DATA AVAILABILITY STATEMENT

The data that support the findings of this study are available from the corresponding author upon reasonable request.

The transcriptomic and lipidomic data sets from this study are available via the Mendeley platform (https://data.mendeley.com/datasets/rdg33vrk4x/1). The SRA metadata associated with transcriptomic data sets are available at https://dataview.ncbi.nlm.nih.gov/object/PRJNA1291293?reviewer=q5be3tf7rd1q4ll37dcat03800. For original data, please contact zhaoxin@ihcams.ac.cn.

REFERENCES

1. Olynyk JK, Ramm GA. Hemochromatosis. N Engl J Med. 2022;387(23):2159‐2170. 10.1056/NEJMra2119758 [DOI] [PubMed] [Google Scholar]
2. Brissot P, Pietrangelo A, Adams PC, de Graaff B, McLaren CE, Loréal O. Haemochromatosis. Nat Rev Dis Primers. 2018;4:18016. 10.1038/nrdp.2018.16 [DOI] [PMC free article] [PubMed] [Google Scholar]
3. Adams PC, Jeffrey G, Ryan J. Haemochromatosis. Lancet. 2023;401(10390):1811‐1821. 10.1016/s0140-6736(23)00287-8 [DOI] [PubMed] [Google Scholar]
4. Brittenham GM. Iron‐chelating therapy for transfusional iron overload. N Engl J Med. 2011;364(2):146‐156. 10.1056/NEJMct1004810 [DOI] [PMC free article] [PubMed] [Google Scholar]
5. Fleming RE, Ponka P. Iron Overload in Human Disease. N Engl J Med. 2012;366(4):348‐359. 10.1056/NEJMra1004967 [DOI] [PubMed] [Google Scholar]
6. Walter K. What is hereditary hemochromatosis? JAMA. 2022;328(18):1879. 10.1001/jama.2022.19462 [DOI] [PubMed] [Google Scholar]
7. Cabantchik IZ, Hershko C. Plasma nontransferrin bound iron‐nontransferrin bound iron revisited: implications for systemic iron overload and in iv iron supplementation. Am J Hematol. 2022;97(1):7‐9. 10.1002/ajh.26374 [DOI] [PubMed] [Google Scholar]
8. Andrews NC. Disorders of iron metabolism. N Engl J Med. 1999;341(26):1986‐1995. 10.1056/nejm199912233412607 [DOI] [PubMed] [Google Scholar]
9. Cabantchik ZI. Labile iron in cells and body fluids: physiology, pathology, and pharmacology. Front Pharmacol. 2014;5:45. 10.3389/fphar.2014.00045 [DOI] [PMC free article] [PubMed] [Google Scholar]
10. Yuan J, Ofengeim D. A guide to cell death pathways. Nat Rev Mol Cell Biol. 2023;25:379‐395. 10.1038/s41580-023-00689-6 [DOI] [PubMed] [Google Scholar]
11. Zhang DD. Ironing out the details of ferroptosis. Nat Cell Biol. 2024;26:1386‐1393. 10.1038/s41556-024-01361-7 [DOI] [PubMed] [Google Scholar]
12. Galy B, Conrad M, Muckenthaler M. Mechanisms controlling cellular and systemic iron homeostasis. Nat Rev Mol Cell Biol. 2023;25:133‐155. 10.1038/s41580-023-00648-1 [DOI] [PubMed] [Google Scholar]
13. Pootrakul P, Breuer W, Sametband M, Sirankapracha P, Hershko C, Cabantchik ZI. Labile plasma iron (LPI) as an indicator of chelatable plasma redox activity in iron‐overloaded β‐thalassemia/HbE patients treated with an oral chelator. Blood. 2004;104(5):1504‐1510. 10.1182/blood-2004-02-0630 [DOI] [PubMed] [Google Scholar]
14. Esposito BP, Breuer W, Sirankapracha P, Pootrakul P, Hershko C, Cabantchik ZI. Labile plasma iron in iron overload: redox activity and susceptibility to chelation. Blood. 2003;102(7):2670‐2677. 10.1182/blood-2003-03-0807 [DOI] [PubMed] [Google Scholar]
15. Wang H, An P, Xie E, et al. Characterization of ferroptosis in murine models of hemochromatosis. Hepatology. 2017;66(2):449‐465. 10.1002/hep.29117 [DOI] [PMC free article] [PubMed] [Google Scholar]
16. Coates TD. Management of iron overload: lessons from transfusion‐dependent hemoglobinopathies. Blood. 2025;145(4):359‐371. 10.1182/blood.2023022502 [DOI] [PubMed] [Google Scholar]
17. Dixon SJ, Lemberg KM, Lamprecht MR, et al. Ferroptosis: an iron‐dependent form of nonapoptotic cell death. Cell. 2012;149(5):1060‐1072. 10.1016/j.cell.2012.03.042 [DOI] [PMC free article] [PubMed] [Google Scholar]
18. Stockwell BR, Friedmann Angeli JP, Bayir H, et al. Ferroptosis: a regulated cell death nexus linking metabolism, redox biology, and disease. Cell. 2017;171(2):273‐285. 10.1016/j.cell.2017.09.021 [DOI] [PMC free article] [PubMed] [Google Scholar]
19. Scarpellini C, Klejborowska G, Lanthier C, Hassannia B, Vanden Berghe T, Augustyns K. Beyond ferrostatin‐1: a comprehensive review of ferroptosis inhibitors. Trends Pharmacol Sci. 2023;44(12):902‐916. 10.1016/j.tips.2023.08.012 [DOI] [PubMed] [Google Scholar]
20. Cabrera E, Crespo G, VanWagner LB. Diagnosis and management of hereditary hemochromatosis. JAMA. 2022;328(18):1862‐1863. 10.1001/jama.2022.17727 [DOI] [PMC free article] [PubMed] [Google Scholar]
21. Crawford DHG, Ramm GA, Bridle KR, Nicoll AJ, Delatycki MB, Olynyk JK. Clinical practice guidelines on hemochromatosis: Asian Pacific Association for the Study of the Liver. Hepatol Int. 2023;17(3):522‐541. 10.1007/s12072-023-10510-3 [DOI] [PMC free article] [PubMed] [Google Scholar]
22. Leitch HA, Buckstein R. How I treat iron overload in adult MDS. Blood. 2025;145(4):383‐396. 10.1182/blood.2023022501 [DOI] [PubMed] [Google Scholar]
23. Hider RC, Hoffbrand AV. The role of deferiprone in iron chelation. N Engl J Med. 2018;379(22):2140‐2150. 10.1056/NEJMra1800219 [DOI] [PubMed] [Google Scholar]
24. Lee JW, Yoon SS, Xiang Shen Z, et al. Iron chelation therapy with deferasirox in patients with aplastic anemia: a subgroup analysis of 116 patients from the EPIC trial. Blood. 2010;116(14):2448‐2454. 10.1182/blood-2010-01-261289 [DOI] [PubMed] [Google Scholar]
25. Greenberg PL, Koller CA, Cabantchik ZI, et al. Prospective assessment of effects on iron‐overload parameters of deferasirox therapy in patients with myelodysplastic syndromes. Leuk Res. 2010;34(12):1560‐1565. 10.1016/j.leukres.2010.06.013 [DOI] [PubMed] [Google Scholar]
26. Brittenham GM, Griffith PM, Nienhuis AW, et al. Efficacy of deferoxamine in preventing complications of iron overload in patients with thalassemia major. N Engl J Med. 1994;331(9):567‐573. 10.1056/nejm199409013310902 [DOI] [PubMed] [Google Scholar]
27. Ganz T. Iron and infection. Int J Hematol. 2018;107(1):7‐15. 10.1007/s12185-017-2366-2 [DOI] [PubMed] [Google Scholar]
28. Wang Y, Huang L, Hua Y, et al. Impact of iron overload by transfusion on survival and leukemia transformation of myelodysplastic syndromes in a single center of China. Hematology. 2021;26(1):874‐880. 10.1080/16078454.2021.1989806 [DOI] [PubMed] [Google Scholar]
29. Ferrara F, Coppi F, Riva R, et al. Labile plasma iron and echocardiographic parameters are associated with cardiac events in β‐thalassemic patients. Eur J Clin Invest. 2023;53(5):e13954. 10.1111/eci.13954 [DOI] [PubMed] [Google Scholar]
30. Porto G. Iron overload and immunity. World J Gastroenterol. 2007;13(35):4707‐4715. 10.3748/wjg.v13.i35.4707 [DOI] [PMC free article] [PubMed] [Google Scholar]
31. Frost JN, Drakesmith H. Iron and the immune system. Nat Rev Immunol. 2025;25:885‐899. 10.1038/s41577-025-01193-y [DOI] [PubMed] [Google Scholar]
32. Lu W, Zhao M, Rajbhandary S, et al. Free iron catalyzes oxidative damage to hematopoietic cells/mesenchymal stem cells in vitro and suppresses hematopoiesis in iron overload patients. Eur J Haematol. 2013;91(3):249‐261. 10.1111/ejh.12159 [DOI] [PubMed] [Google Scholar]
33. de Swart L, Reiniers C, Bagguley T, et al. Labile plasma iron levels predict survival in patients with lower‐risk myelodysplastic syndromes. Haematologica. 2018;103(1):69‐79. 10.3324/haematol.2017.171884 [DOI] [PMC free article] [PubMed] [Google Scholar]
34. Isidori A, Borin L, Elli E, et al. Iron toxicity – its effect on the bone marrow. Blood Rev. 2018;32(6):473‐479. 10.1016/j.blre.2018.04.004 [DOI] [PubMed] [Google Scholar]
35. Jin X, He X, Cao X, et al. Iron overload impairs normal hematopoietic stem and progenitor cells through reactive oxygen species and shortens survival in myelodysplastic syndrome mice. Haematologica. 2018;103(10):1627‐1634. 10.3324/haematol.2018.193128 [DOI] [PMC free article] [PubMed] [Google Scholar]
36. Pawelec K, Salamonowicz M, Panasiuk A, et al. Influence of iron overload on immunosuppressive therapy in children with severe aplastic anemia. Adv Exp Med Biol. 2015;866:83‐89. 10.1007/5584_2015_148 [DOI] [PubMed] [Google Scholar]
37. Xie C, Zhao H, Bao X, Fu H, Lou L. Pharmacological characterization of hetrombopag, a novel orally active human thrombopoietin receptor agonist. J Cell Mol Med. 2018;22(11):5367‐5377. 10.1111/jcmm.13809 [DOI] [PMC free article] [PubMed] [Google Scholar]
38. Peng G, He G, Chang H, et al. A multicenter phase II study on the efficacy and safety of hetrombopag in patients with severe aplastic anemia refractory to immunosuppressive therapy. Ther Adv Hematol. 2022;13:20406207221085197. 10.1177/20406207221085197 [DOI] [PMC free article] [PubMed] [Google Scholar]
39. Mei H, Liu X, Li Y, et al. Dose tapering to withdrawal stage and long‐term efficacy and safety of hetrombopag for the treatment of immune thrombocytopenia: results from an open‐label extension study. J Thromb Haemostasis. 2022;20(3):716‐728. 10.1111/jth.15602 [DOI] [PubMed] [Google Scholar]
40. Mei H, Liu X, Li Y, et al. A multicenter, randomized phase III trial of hetrombopag: a novel thrombopoietin receptor agonist for the treatment of immune thrombocytopenia. J Hematol Oncol. 2021;14(1):37. 10.1186/s13045-021-01047-9 [DOI] [PMC free article] [PubMed] [Google Scholar]
41. Syed YY. Hetrombopag: first approval. Drugs. 2021;81(13):1581‐1585. 10.1007/s40265-021-01575-1 [DOI] [PubMed] [Google Scholar]
42. Yang W, Zhao X, Liu X, et al. Hetrombopag plus porcine ATG and cyclosporine for the treatment of aplastic anaemia: early outcomes of a prospective pilot study. Exp Hematol Oncol. 2023;12(1):16. 10.1186/s40164-023-00377-3 [DOI] [PMC free article] [PubMed] [Google Scholar]
43. Yang W, Zhao X, He G, et al. Iron chelation of hetrombopag in aplastic anemia: a post hoc analysis of a phase II study. Ann Hematol. 2022;101(12):2611‐2616. 10.1007/s00277-022-04968-8 [DOI] [PubMed] [Google Scholar]
44. Jin P, Wang J, Li X, et al. Evolution of iron burden in acquired aplastic anemia: a cohort study of more than 3‐year follow‐up. Int J Hematol. 2015;101(1):13‐22. 10.1007/s12185-014-1708-6 [DOI] [PubMed] [Google Scholar]
45. Italia K, Colah R, Ghosh K. Experimental animal model to study iron overload and iron chelation and review of other such models. Blood Cells Mol Dis. 2015;55(3):194‐199. 10.1016/j.bcmd.2015.06.003 [DOI] [PubMed] [Google Scholar]
46. Ru Q, Li Y, Chen L, Wu Y, Min J, Wang F. Iron homeostasis and ferroptosis in human diseases: mechanisms and therapeutic prospects. Signal Transduct Target Ther. 2024;9(1):271. 10.1038/s41392-024-01969-z [DOI] [PMC free article] [PubMed] [Google Scholar]
47. Zhao J, Jia Y, Mahmut D, et al. Human hematopoietic stem cell vulnerability to ferroptosis. Cell. 2023;186(4):732‐747.e16. 10.1016/j.cell.2023.01.020 [DOI] [PMC free article] [PubMed] [Google Scholar]
48. Morgan PK, Pernes G, Huynh K, et al. A lipid atlas of human and mouse immune cells provides insights into ferroptosis susceptibility. Nature Cell Biol. 2024;26:645‐659. 10.1038/s41556-024-01377-z [DOI] [PubMed] [Google Scholar]
49. Kumar A, Ye C, Nkansah A, et al. Iron regulates the quiescence of naive CD4 T cells by controlling mitochondria and cellular metabolism. Proc Natl Acad Sci USA. 2024;121(17):e2318420121. 10.1073/pnas.2318420121 [DOI] [PMC free article] [PubMed] [Google Scholar]
50. Muckenthaler MU, Rivella S, Hentze MW, Galy B. A red carpet for iron metabolism. Cell. 2017;168(3):344‐361. 10.1016/j.cell.2016.12.034 [DOI] [PMC free article] [PubMed] [Google Scholar]
51. Camaschella C, Nai A, Silvestri L. Iron metabolism and iron disorders revisited in the hepcidin era. Haematologica. 2020;105(2):260‐272. 10.3324/haematol.2019.232124 [DOI] [PMC free article] [PubMed] [Google Scholar]
52. Wang C‐Y, Babitt JL. Liver iron sensing and body iron homeostasis. Blood. 2019;133(1):18‐29. 10.1182/blood-2018-06-815894 [DOI] [PMC free article] [PubMed] [Google Scholar]
53. Sun S, Shen J, Jiang J, Wang F, Min J. Targeting ferroptosis opens new avenues for the development of novel therapeutics. Signal Transduct Target Ther. 2023;8(1):372. 10.1038/s41392-023-01606-1 [DOI] [PMC free article] [PubMed] [Google Scholar]
54. Fernández‐Real JM, Manco M. Effects of iron overload on chronic metabolic diseases. Lancet Diabetes Endocrinol. 2014;2(6):513‐526. 10.1016/s2213-8587(13)70174-8 [DOI] [PubMed] [Google Scholar]
55. Stockwell BR. Ferroptosis turns 10: Emerging mechanisms, physiological functions, and therapeutic applications. Cell. 2022;185(14):2401‐2421. 10.1016/j.cell.2022.06.003 [DOI] [PMC free article] [PubMed] [Google Scholar]
56. Zou Y, Henry WS, Ricq EL, et al. Plasticity of ether lipids promotes ferroptosis susceptibility and evasion. Nature. 2020;585(7826):603‐608. 10.1038/s41586-020-2732-8 [DOI] [PMC free article] [PubMed] [Google Scholar]
57. Noguchi N, Saito Y, Niki E. Lipid peroxidation, ferroptosis and antioxidants. Free Radic Biol Med. 2025;237:228‐238. 10.1016/j.freeradbiomed.2025.05.393 [DOI] [PubMed] [Google Scholar]
58. Timmers PRHJ, Wilson JF, Joshi PK, Deelen J. Multivariate genomic scan implicates novel loci and haem metabolism in human ageing. Nat Commun. 2020;11(1):3570. 10.1038/s41467-020-17312-3 [DOI] [PMC free article] [PubMed] [Google Scholar]
59. Giudice V, Selleri C. Aplastic anemia: pathophysiology. Sem Hematol. 2022;59(1):13‐20. 10.1053/j.seminhematol.2021.12.002 [DOI] [PubMed] [Google Scholar]
60. Jensen PD, Heickendorff L, Pedersen B, et al. The effect of iron chelation on haemopoiesis in MDS patients with transfusional iron overload. Br J Haematol. 1996;94(2):288‐299. 10.1046/j.1365-2141.1996.d01-1795.x [DOI] [PubMed] [Google Scholar]
61. Oliva EN, Ronco F, Marino A, Alati C, Praticò G, Nobile F. Iron chelation therapy associated with improvement of hematopoiesis in transfusion‐dependent patients. Transfusion. 2010;50(7):1568‐1570. 10.1111/j.1537-2995.2010.02617.x [DOI] [PubMed] [Google Scholar]
62. Leitch HA, Gattermann N. Hematologic improvement with iron chelation therapy in myelodysplastic syndromes: Clinical data, potential mechanisms, and outstanding questions. Crit Rev Oncol Hematol. 2019;141:54‐72. 10.1016/j.critrevonc.2019.06.002 [DOI] [PubMed] [Google Scholar]
63. Lee JW, Yoon SS, Shen ZX, et al. Hematologic responses in patients with aplastic anemia treated with deferasirox: a post hoc analysis from the EPIC study. Haematologica. 2013;98(7):1045‐1048. 10.3324/haematol.2012.077669 [DOI] [PMC free article] [PubMed] [Google Scholar]
64. Lee SE, Yahng SA, Cho BS, et al. Improvement in hematopoiesis after iron chelation therapy with deferasirox in patients with aplastic anemia. Acta Haematol. 2013;129(2):72‐77. 10.1159/000342772 [DOI] [PubMed] [Google Scholar]
65. Guariglia R, Martorelli MC, Villani O, et al. Positive effects on hematopoiesis in patients with myelodysplastic syndrome receiving deferasirox as oral iron chelation therapy: a brief review. Leuk Res. 2011;35(5):566‐570. 10.1016/j.leukres.2010.11.027 [DOI] [PubMed] [Google Scholar]
66. Zhang F, Zhao X, Chang H, et al. Hetrombopag added to immunosuppressive therapy in first‐line treatment of severe aplastic anemia: a randomized, double‐blind, placebo‐controlled phase 3 trial. Blood. 2024;144(Suppl 1):304‐305. doi:10.1182/blood-2024-206377 [Google Scholar]
67. Vlachodimitropoulou E, Chen YL, Garbowski M, et al. Eltrombopag: a powerful chelator of cellular or extracellular iron(III) alone or combined with a second chelator. Blood. 2017;130(17):1923‐1933. 10.1182/blood-2016-10-740241 [DOI] [PMC free article] [PubMed] [Google Scholar]
68. Bazuave GN, Buser A, Gerull S, Tichelli A, Stern M. Prognostic impact of iron parameters in patients undergoing allo‐SCT. Bone Marrow Transplant. 2012;47(1):60‐64. 10.1038/bmt.2011.13 [DOI] [PubMed] [Google Scholar]
69. Pan T, Ji Y, Liu H, et al. Impact of iron overload and iron Chelation with deferasirox on outcomes of patients with severe aplastic anemia after allogeneic hematopoietic stem cell transplantation. Transpl Cell Ther. 2023;29:507.e1‐507.e8. 10.1016/j.jtct.2023.04.016 [DOI] [PubMed] [Google Scholar]
70. Angelucci E. How I manage iron overload in the hematopoietic cell transplantation setting. Blood. 2025;145(4):372‐382. 10.1182/blood.2023022500 [DOI] [PubMed] [Google Scholar]
71. Young DJ, Fan X, Groarke EM, et al. Long‐term eltrombopag for bone marrow failure depletes iron. Am J Hematol. 2022;97:791‐801. 10.1002/ajh.26543 [DOI] [PMC free article] [PubMed] [Google Scholar]
72. Hu Q, Zhang Y, Lou H, et al. GPX4 and vitamin E cooperatively protect hematopoietic stem and progenitor cells from lipid peroxidation and ferroptosis. Cell Death Dis. 2021;12(7):706. 10.1038/s41419-021-04008-9 [DOI] [PMC free article] [PubMed] [Google Scholar]
73. ElLaboudy MA, Saber MM, Adly AA, Ismail EA, Ibrahim FA, Elalfy OM. Oxidative stress markers and tissue iron overload after 12‐months vitamin E supplementation for children with transfusion‐dependent β‐thalassemia on different iron chelators: a randomized placebo‐controlled trial. Clin Nutr. 2025;50:154‐163. 10.1016/j.clnu.2025.05.003 [DOI] [PubMed] [Google Scholar]
74. Hemprachitchai N, Praneetponkang R, Wongwerawattanakoon P, et al. Measures of cellular oxidative damage following vitamin E supplementation in young patients with transfusion‐dependent thalassemia: a double‐blind randomized controlled trial. BMC Pediatr. 2025;25(1):405. 10.1186/s12887-025-05741-2 [DOI] [PMC free article] [PubMed] [Google Scholar]
75. Mann J, Reznik E, Santer M, et al. Ferroptosis inhibition by oleic acid mitigates iron‐overload‐induced injury. Cell Chem Biol. 2024;31:249‐264. 10.1016/j.chembiol.2023.10.012 [DOI] [PMC free article] [PubMed] [Google Scholar]
76. Semenova Y, Bjørklund G, Butnariu M, Peana M. Iron‐related biomarkers in the diagnosis and management of iron disorders. Curr Med Chem. 2024;31:4233‐4248. 10.2174/0109298673263003231228060800 [DOI] [PubMed] [Google Scholar]
77. Risca G, Pelucchi S, Mariani R, et al. Transferrin saturation and serum ferritin are main predictors of liver iron content in subjects with hyperferritinemia. Clin Gastroenterol Hepatol. 2026;24:141‐149. 10.1016/j.cgh.2025.02.033 [DOI] [PubMed] [Google Scholar]
78. Shen S, Hu Q, Yang C, Jiang Z, Chen M, Han B. Adding hetrombopag to cyclosporine a improved response of patients with newly diagnosed transfusion‐dependent non‐severe aplastic anemia. Ann Hematol. 2024;103(10):4247‐4249. 10.1007/s00277-024-05941-3 [DOI] [PubMed] [Google Scholar]
79. Qin S, Wang Y, Yao J, et al. Hetrombopag for the management of chemotherapy‐induced thrombocytopenia in patients with advanced solid tumors: a multicenter, randomized, double‐blind, placebo‐controlled, phase II study. Ther Adv Med Oncol. 2024;16:17588359241260985. 10.1177/17588359241260985 [DOI] [PMC free article] [PubMed] [Google Scholar]
80. Xu X, Yang R, Jia Y, et al. Comparison of thrombopoietin receptor agonists plus recombinant human thrombopoietin versus recombinant human thrombopoietin alone for hematopoietic reconstruction in multiple myeloma patients undergoing autologous hematopoietic stem cell transplantation. Transpl Cell Ther. 2025;31(2):84.e1‐84.e8. 10.1016/j.jtct.2024.12.015 [DOI] [PubMed] [Google Scholar]
81. Ni J, Hong J, Liang X, et al. Efficacy and safety of hetrombopag in the treatment of recombinant human thrombopoietin‐resistant thrombocytopenia after allogeneic hematopoietic stem cell transplantation. Res Pract Thromb Haemost. 2024;8(7):102578. 10.1016/j.rpth.2024.102578 [DOI] [PMC free article] [PubMed] [Google Scholar]
82. Feng Y, Wang L, Ren M, et al. Efficacy and safety of hetrombopag versus thrombopoietin in promoting platelet engraftment after allogeneic hematopoietic stem cell transplantation: a prospective, multicenter, randomized controlled clinical trial. Am J Hematol. 2025;100:1533‐1542. 10.1002/ajh.27746 [DOI] [PubMed] [Google Scholar]
83. Teh MR, Armitage AE, Drakesmith H. Why cells need iron: a compendium of iron utilisation. Trends Endocrinol Metab. 2024;35:1026‐1049. 10.1016/j.tem.2024.04.015 [DOI] [PMC free article] [PubMed] [Google Scholar]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

Supplemental Material_R2.

HEM3-10-e70331-s001.docx^{(7.7MB, docx)}

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

[hem370331-bib-0001] 1. Olynyk JK, Ramm GA. Hemochromatosis. N Engl J Med. 2022;387(23):2159‐2170. 10.1056/NEJMra2119758 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0002] 2. Brissot P, Pietrangelo A, Adams PC, de Graaff B, McLaren CE, Loréal O. Haemochromatosis. Nat Rev Dis Primers. 2018;4:18016. 10.1038/nrdp.2018.16 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0003] 3. Adams PC, Jeffrey G, Ryan J. Haemochromatosis. Lancet. 2023;401(10390):1811‐1821. 10.1016/s0140-6736(23)00287-8 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0004] 4. Brittenham GM. Iron‐chelating therapy for transfusional iron overload. N Engl J Med. 2011;364(2):146‐156. 10.1056/NEJMct1004810 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0005] 5. Fleming RE, Ponka P. Iron Overload in Human Disease. N Engl J Med. 2012;366(4):348‐359. 10.1056/NEJMra1004967 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0006] 6. Walter K. What is hereditary hemochromatosis? JAMA. 2022;328(18):1879. 10.1001/jama.2022.19462 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0007] 7. Cabantchik IZ, Hershko C. Plasma nontransferrin bound iron‐nontransferrin bound iron revisited: implications for systemic iron overload and in iv iron supplementation. Am J Hematol. 2022;97(1):7‐9. 10.1002/ajh.26374 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0008] 8. Andrews NC. Disorders of iron metabolism. N Engl J Med. 1999;341(26):1986‐1995. 10.1056/nejm199912233412607 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0009] 9. Cabantchik ZI. Labile iron in cells and body fluids: physiology, pathology, and pharmacology. Front Pharmacol. 2014;5:45. 10.3389/fphar.2014.00045 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0010] 10. Yuan J, Ofengeim D. A guide to cell death pathways. Nat Rev Mol Cell Biol. 2023;25:379‐395. 10.1038/s41580-023-00689-6 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0011] 11. Zhang DD. Ironing out the details of ferroptosis. Nat Cell Biol. 2024;26:1386‐1393. 10.1038/s41556-024-01361-7 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0012] 12. Galy B, Conrad M, Muckenthaler M. Mechanisms controlling cellular and systemic iron homeostasis. Nat Rev Mol Cell Biol. 2023;25:133‐155. 10.1038/s41580-023-00648-1 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0013] 13. Pootrakul P, Breuer W, Sametband M, Sirankapracha P, Hershko C, Cabantchik ZI. Labile plasma iron (LPI) as an indicator of chelatable plasma redox activity in iron‐overloaded β‐thalassemia/HbE patients treated with an oral chelator. Blood. 2004;104(5):1504‐1510. 10.1182/blood-2004-02-0630 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0014] 14. Esposito BP, Breuer W, Sirankapracha P, Pootrakul P, Hershko C, Cabantchik ZI. Labile plasma iron in iron overload: redox activity and susceptibility to chelation. Blood. 2003;102(7):2670‐2677. 10.1182/blood-2003-03-0807 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0015] 15. Wang H, An P, Xie E, et al. Characterization of ferroptosis in murine models of hemochromatosis. Hepatology. 2017;66(2):449‐465. 10.1002/hep.29117 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0016] 16. Coates TD. Management of iron overload: lessons from transfusion‐dependent hemoglobinopathies. Blood. 2025;145(4):359‐371. 10.1182/blood.2023022502 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0017] 17. Dixon SJ, Lemberg KM, Lamprecht MR, et al. Ferroptosis: an iron‐dependent form of nonapoptotic cell death. Cell. 2012;149(5):1060‐1072. 10.1016/j.cell.2012.03.042 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0018] 18. Stockwell BR, Friedmann Angeli JP, Bayir H, et al. Ferroptosis: a regulated cell death nexus linking metabolism, redox biology, and disease. Cell. 2017;171(2):273‐285. 10.1016/j.cell.2017.09.021 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0019] 19. Scarpellini C, Klejborowska G, Lanthier C, Hassannia B, Vanden Berghe T, Augustyns K. Beyond ferrostatin‐1: a comprehensive review of ferroptosis inhibitors. Trends Pharmacol Sci. 2023;44(12):902‐916. 10.1016/j.tips.2023.08.012 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0020] 20. Cabrera E, Crespo G, VanWagner LB. Diagnosis and management of hereditary hemochromatosis. JAMA. 2022;328(18):1862‐1863. 10.1001/jama.2022.17727 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0021] 21. Crawford DHG, Ramm GA, Bridle KR, Nicoll AJ, Delatycki MB, Olynyk JK. Clinical practice guidelines on hemochromatosis: Asian Pacific Association for the Study of the Liver. Hepatol Int. 2023;17(3):522‐541. 10.1007/s12072-023-10510-3 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0022] 22. Leitch HA, Buckstein R. How I treat iron overload in adult MDS. Blood. 2025;145(4):383‐396. 10.1182/blood.2023022501 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0023] 23. Hider RC, Hoffbrand AV. The role of deferiprone in iron chelation. N Engl J Med. 2018;379(22):2140‐2150. 10.1056/NEJMra1800219 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0024] 24. Lee JW, Yoon SS, Xiang Shen Z, et al. Iron chelation therapy with deferasirox in patients with aplastic anemia: a subgroup analysis of 116 patients from the EPIC trial. Blood. 2010;116(14):2448‐2454. 10.1182/blood-2010-01-261289 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0025] 25. Greenberg PL, Koller CA, Cabantchik ZI, et al. Prospective assessment of effects on iron‐overload parameters of deferasirox therapy in patients with myelodysplastic syndromes. Leuk Res. 2010;34(12):1560‐1565. 10.1016/j.leukres.2010.06.013 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0026] 26. Brittenham GM, Griffith PM, Nienhuis AW, et al. Efficacy of deferoxamine in preventing complications of iron overload in patients with thalassemia major. N Engl J Med. 1994;331(9):567‐573. 10.1056/nejm199409013310902 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0027] 27. Ganz T. Iron and infection. Int J Hematol. 2018;107(1):7‐15. 10.1007/s12185-017-2366-2 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0028] 28. Wang Y, Huang L, Hua Y, et al. Impact of iron overload by transfusion on survival and leukemia transformation of myelodysplastic syndromes in a single center of China. Hematology. 2021;26(1):874‐880. 10.1080/16078454.2021.1989806 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0029] 29. Ferrara F, Coppi F, Riva R, et al. Labile plasma iron and echocardiographic parameters are associated with cardiac events in β‐thalassemic patients. Eur J Clin Invest. 2023;53(5):e13954. 10.1111/eci.13954 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0030] 30. Porto G. Iron overload and immunity. World J Gastroenterol. 2007;13(35):4707‐4715. 10.3748/wjg.v13.i35.4707 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0031] 31. Frost JN, Drakesmith H. Iron and the immune system. Nat Rev Immunol. 2025;25:885‐899. 10.1038/s41577-025-01193-y [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0032] 32. Lu W, Zhao M, Rajbhandary S, et al. Free iron catalyzes oxidative damage to hematopoietic cells/mesenchymal stem cells in vitro and suppresses hematopoiesis in iron overload patients. Eur J Haematol. 2013;91(3):249‐261. 10.1111/ejh.12159 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0033] 33. de Swart L, Reiniers C, Bagguley T, et al. Labile plasma iron levels predict survival in patients with lower‐risk myelodysplastic syndromes. Haematologica. 2018;103(1):69‐79. 10.3324/haematol.2017.171884 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0034] 34. Isidori A, Borin L, Elli E, et al. Iron toxicity – its effect on the bone marrow. Blood Rev. 2018;32(6):473‐479. 10.1016/j.blre.2018.04.004 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0035] 35. Jin X, He X, Cao X, et al. Iron overload impairs normal hematopoietic stem and progenitor cells through reactive oxygen species and shortens survival in myelodysplastic syndrome mice. Haematologica. 2018;103(10):1627‐1634. 10.3324/haematol.2018.193128 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0036] 36. Pawelec K, Salamonowicz M, Panasiuk A, et al. Influence of iron overload on immunosuppressive therapy in children with severe aplastic anemia. Adv Exp Med Biol. 2015;866:83‐89. 10.1007/5584_2015_148 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0037] 37. Xie C, Zhao H, Bao X, Fu H, Lou L. Pharmacological characterization of hetrombopag, a novel orally active human thrombopoietin receptor agonist. J Cell Mol Med. 2018;22(11):5367‐5377. 10.1111/jcmm.13809 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0038] 38. Peng G, He G, Chang H, et al. A multicenter phase II study on the efficacy and safety of hetrombopag in patients with severe aplastic anemia refractory to immunosuppressive therapy. Ther Adv Hematol. 2022;13:20406207221085197. 10.1177/20406207221085197 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0039] 39. Mei H, Liu X, Li Y, et al. Dose tapering to withdrawal stage and long‐term efficacy and safety of hetrombopag for the treatment of immune thrombocytopenia: results from an open‐label extension study. J Thromb Haemostasis. 2022;20(3):716‐728. 10.1111/jth.15602 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0040] 40. Mei H, Liu X, Li Y, et al. A multicenter, randomized phase III trial of hetrombopag: a novel thrombopoietin receptor agonist for the treatment of immune thrombocytopenia. J Hematol Oncol. 2021;14(1):37. 10.1186/s13045-021-01047-9 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0041] 41. Syed YY. Hetrombopag: first approval. Drugs. 2021;81(13):1581‐1585. 10.1007/s40265-021-01575-1 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0042] 42. Yang W, Zhao X, Liu X, et al. Hetrombopag plus porcine ATG and cyclosporine for the treatment of aplastic anaemia: early outcomes of a prospective pilot study. Exp Hematol Oncol. 2023;12(1):16. 10.1186/s40164-023-00377-3 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0043] 43. Yang W, Zhao X, He G, et al. Iron chelation of hetrombopag in aplastic anemia: a post hoc analysis of a phase II study. Ann Hematol. 2022;101(12):2611‐2616. 10.1007/s00277-022-04968-8 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0044] 44. Jin P, Wang J, Li X, et al. Evolution of iron burden in acquired aplastic anemia: a cohort study of more than 3‐year follow‐up. Int J Hematol. 2015;101(1):13‐22. 10.1007/s12185-014-1708-6 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0045] 45. Italia K, Colah R, Ghosh K. Experimental animal model to study iron overload and iron chelation and review of other such models. Blood Cells Mol Dis. 2015;55(3):194‐199. 10.1016/j.bcmd.2015.06.003 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0046] 46. Ru Q, Li Y, Chen L, Wu Y, Min J, Wang F. Iron homeostasis and ferroptosis in human diseases: mechanisms and therapeutic prospects. Signal Transduct Target Ther. 2024;9(1):271. 10.1038/s41392-024-01969-z [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0047] 47. Zhao J, Jia Y, Mahmut D, et al. Human hematopoietic stem cell vulnerability to ferroptosis. Cell. 2023;186(4):732‐747.e16. 10.1016/j.cell.2023.01.020 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0048] 48. Morgan PK, Pernes G, Huynh K, et al. A lipid atlas of human and mouse immune cells provides insights into ferroptosis susceptibility. Nature Cell Biol. 2024;26:645‐659. 10.1038/s41556-024-01377-z [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0049] 49. Kumar A, Ye C, Nkansah A, et al. Iron regulates the quiescence of naive CD4 T cells by controlling mitochondria and cellular metabolism. Proc Natl Acad Sci USA. 2024;121(17):e2318420121. 10.1073/pnas.2318420121 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0050] 50. Muckenthaler MU, Rivella S, Hentze MW, Galy B. A red carpet for iron metabolism. Cell. 2017;168(3):344‐361. 10.1016/j.cell.2016.12.034 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0051] 51. Camaschella C, Nai A, Silvestri L. Iron metabolism and iron disorders revisited in the hepcidin era. Haematologica. 2020;105(2):260‐272. 10.3324/haematol.2019.232124 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0052] 52. Wang C‐Y, Babitt JL. Liver iron sensing and body iron homeostasis. Blood. 2019;133(1):18‐29. 10.1182/blood-2018-06-815894 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0053] 53. Sun S, Shen J, Jiang J, Wang F, Min J. Targeting ferroptosis opens new avenues for the development of novel therapeutics. Signal Transduct Target Ther. 2023;8(1):372. 10.1038/s41392-023-01606-1 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0054] 54. Fernández‐Real JM, Manco M. Effects of iron overload on chronic metabolic diseases. Lancet Diabetes Endocrinol. 2014;2(6):513‐526. 10.1016/s2213-8587(13)70174-8 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0055] 55. Stockwell BR. Ferroptosis turns 10: Emerging mechanisms, physiological functions, and therapeutic applications. Cell. 2022;185(14):2401‐2421. 10.1016/j.cell.2022.06.003 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0056] 56. Zou Y, Henry WS, Ricq EL, et al. Plasticity of ether lipids promotes ferroptosis susceptibility and evasion. Nature. 2020;585(7826):603‐608. 10.1038/s41586-020-2732-8 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0057] 57. Noguchi N, Saito Y, Niki E. Lipid peroxidation, ferroptosis and antioxidants. Free Radic Biol Med. 2025;237:228‐238. 10.1016/j.freeradbiomed.2025.05.393 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0058] 58. Timmers PRHJ, Wilson JF, Joshi PK, Deelen J. Multivariate genomic scan implicates novel loci and haem metabolism in human ageing. Nat Commun. 2020;11(1):3570. 10.1038/s41467-020-17312-3 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0059] 59. Giudice V, Selleri C. Aplastic anemia: pathophysiology. Sem Hematol. 2022;59(1):13‐20. 10.1053/j.seminhematol.2021.12.002 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0060] 60. Jensen PD, Heickendorff L, Pedersen B, et al. The effect of iron chelation on haemopoiesis in MDS patients with transfusional iron overload. Br J Haematol. 1996;94(2):288‐299. 10.1046/j.1365-2141.1996.d01-1795.x [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0061] 61. Oliva EN, Ronco F, Marino A, Alati C, Praticò G, Nobile F. Iron chelation therapy associated with improvement of hematopoiesis in transfusion‐dependent patients. Transfusion. 2010;50(7):1568‐1570. 10.1111/j.1537-2995.2010.02617.x [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0062] 62. Leitch HA, Gattermann N. Hematologic improvement with iron chelation therapy in myelodysplastic syndromes: Clinical data, potential mechanisms, and outstanding questions. Crit Rev Oncol Hematol. 2019;141:54‐72. 10.1016/j.critrevonc.2019.06.002 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0063] 63. Lee JW, Yoon SS, Shen ZX, et al. Hematologic responses in patients with aplastic anemia treated with deferasirox: a post hoc analysis from the EPIC study. Haematologica. 2013;98(7):1045‐1048. 10.3324/haematol.2012.077669 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0064] 64. Lee SE, Yahng SA, Cho BS, et al. Improvement in hematopoiesis after iron chelation therapy with deferasirox in patients with aplastic anemia. Acta Haematol. 2013;129(2):72‐77. 10.1159/000342772 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0065] 65. Guariglia R, Martorelli MC, Villani O, et al. Positive effects on hematopoiesis in patients with myelodysplastic syndrome receiving deferasirox as oral iron chelation therapy: a brief review. Leuk Res. 2011;35(5):566‐570. 10.1016/j.leukres.2010.11.027 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0066] 66. Zhang F, Zhao X, Chang H, et al. Hetrombopag added to immunosuppressive therapy in first‐line treatment of severe aplastic anemia: a randomized, double‐blind, placebo‐controlled phase 3 trial. Blood. 2024;144(Suppl 1):304‐305. doi:10.1182/blood-2024-206377 [Google Scholar]

[hem370331-bib-0067] 67. Vlachodimitropoulou E, Chen YL, Garbowski M, et al. Eltrombopag: a powerful chelator of cellular or extracellular iron(III) alone or combined with a second chelator. Blood. 2017;130(17):1923‐1933. 10.1182/blood-2016-10-740241 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0068] 68. Bazuave GN, Buser A, Gerull S, Tichelli A, Stern M. Prognostic impact of iron parameters in patients undergoing allo‐SCT. Bone Marrow Transplant. 2012;47(1):60‐64. 10.1038/bmt.2011.13 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0069] 69. Pan T, Ji Y, Liu H, et al. Impact of iron overload and iron Chelation with deferasirox on outcomes of patients with severe aplastic anemia after allogeneic hematopoietic stem cell transplantation. Transpl Cell Ther. 2023;29:507.e1‐507.e8. 10.1016/j.jtct.2023.04.016 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0070] 70. Angelucci E. How I manage iron overload in the hematopoietic cell transplantation setting. Blood. 2025;145(4):372‐382. 10.1182/blood.2023022500 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0071] 71. Young DJ, Fan X, Groarke EM, et al. Long‐term eltrombopag for bone marrow failure depletes iron. Am J Hematol. 2022;97:791‐801. 10.1002/ajh.26543 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0072] 72. Hu Q, Zhang Y, Lou H, et al. GPX4 and vitamin E cooperatively protect hematopoietic stem and progenitor cells from lipid peroxidation and ferroptosis. Cell Death Dis. 2021;12(7):706. 10.1038/s41419-021-04008-9 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0073] 73. ElLaboudy MA, Saber MM, Adly AA, Ismail EA, Ibrahim FA, Elalfy OM. Oxidative stress markers and tissue iron overload after 12‐months vitamin E supplementation for children with transfusion‐dependent β‐thalassemia on different iron chelators: a randomized placebo‐controlled trial. Clin Nutr. 2025;50:154‐163. 10.1016/j.clnu.2025.05.003 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0074] 74. Hemprachitchai N, Praneetponkang R, Wongwerawattanakoon P, et al. Measures of cellular oxidative damage following vitamin E supplementation in young patients with transfusion‐dependent thalassemia: a double‐blind randomized controlled trial. BMC Pediatr. 2025;25(1):405. 10.1186/s12887-025-05741-2 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0075] 75. Mann J, Reznik E, Santer M, et al. Ferroptosis inhibition by oleic acid mitigates iron‐overload‐induced injury. Cell Chem Biol. 2024;31:249‐264. 10.1016/j.chembiol.2023.10.012 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0076] 76. Semenova Y, Bjørklund G, Butnariu M, Peana M. Iron‐related biomarkers in the diagnosis and management of iron disorders. Curr Med Chem. 2024;31:4233‐4248. 10.2174/0109298673263003231228060800 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0077] 77. Risca G, Pelucchi S, Mariani R, et al. Transferrin saturation and serum ferritin are main predictors of liver iron content in subjects with hyperferritinemia. Clin Gastroenterol Hepatol. 2026;24:141‐149. 10.1016/j.cgh.2025.02.033 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0078] 78. Shen S, Hu Q, Yang C, Jiang Z, Chen M, Han B. Adding hetrombopag to cyclosporine a improved response of patients with newly diagnosed transfusion‐dependent non‐severe aplastic anemia. Ann Hematol. 2024;103(10):4247‐4249. 10.1007/s00277-024-05941-3 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0079] 79. Qin S, Wang Y, Yao J, et al. Hetrombopag for the management of chemotherapy‐induced thrombocytopenia in patients with advanced solid tumors: a multicenter, randomized, double‐blind, placebo‐controlled, phase II study. Ther Adv Med Oncol. 2024;16:17588359241260985. 10.1177/17588359241260985 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0080] 80. Xu X, Yang R, Jia Y, et al. Comparison of thrombopoietin receptor agonists plus recombinant human thrombopoietin versus recombinant human thrombopoietin alone for hematopoietic reconstruction in multiple myeloma patients undergoing autologous hematopoietic stem cell transplantation. Transpl Cell Ther. 2025;31(2):84.e1‐84.e8. 10.1016/j.jtct.2024.12.015 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0081] 81. Ni J, Hong J, Liang X, et al. Efficacy and safety of hetrombopag in the treatment of recombinant human thrombopoietin‐resistant thrombocytopenia after allogeneic hematopoietic stem cell transplantation. Res Pract Thromb Haemost. 2024;8(7):102578. 10.1016/j.rpth.2024.102578 [DOI] [PMC free article] [PubMed] [Google Scholar]

[hem370331-bib-0082] 82. Feng Y, Wang L, Ren M, et al. Efficacy and safety of hetrombopag versus thrombopoietin in promoting platelet engraftment after allogeneic hematopoietic stem cell transplantation: a prospective, multicenter, randomized controlled clinical trial. Am J Hematol. 2025;100:1533‐1542. 10.1002/ajh.27746 [DOI] [PubMed] [Google Scholar]

[hem370331-bib-0083] 83. Teh MR, Armitage AE, Drakesmith H. Why cells need iron: a compendium of iron utilisation. Trends Endocrinol Metab. 2024;35:1026‐1049. 10.1016/j.tem.2024.04.015 [DOI] [PMC free article] [PubMed] [Google Scholar]

PERMALINK

Longitudinal clinical and preclinical studies identify hetrombopag as a potent chelator for systemic iron overload

Yufei Zhao

Lingxiao Xing

Baohang Zhang

Wenrui Yang

Xiangrong Hu

Xu Liu

Xiawan Yang

Weiru Liang

Yimeng Shi

Jing Hu

Xiaoxia Li

Rui Kang

Guangxin Peng

Yuan Li

Xiao Hu

Youzhen Xiong

Liping Jing

Weiping Yuan

Sidan Li

Fengkui Zhang

Xin Zhao

Abstract

INTRODUCTION

MATERIALS AND METHODS

Patients

Animals

RESULTS

Iron burden in patients with SAA before standard IST treatment and during follow‐up

Figure 1.

Iron‐dependent lipid peroxide accumulation and systemic disorders in transfusional IO

Figure 2.

HPAG alleviates systemic IO as a novel iron‐chelating agent, beyond a TPO‐RA

Figure 3.

Figure 4.

HPAG provides both prophylactic and therapeutic benefits in systemic IO

Figure 5.

HPAG ameliorates iron‐dependent lipid peroxidation and shows ferroptosis‐inhibitory effects

Figure 6.

HPAG reduces the accumulated iron burden in patients with SAA, providing both prophylactic and therapeutic benefits

Figure 7.

Figure 8.

DISCUSSION

AUTHOR CONTRIBUTIONS

CONFLICT OF INTEREST STATEMENT

ETHICS STATEMENT

FUNDING

Supporting information

ACKNOWLEDGMENTS

Contributor Information

DATA AVAILABILITY STATEMENT

REFERENCES

Associated Data

Supplementary Materials

Data Availability Statement

ACTIONS

PERMALINK

RESOURCES

Similar articles

Cited by other articles

Links to NCBI Databases