bims-tremyl Biomed News
on Therapy resistance biology in myeloid leukemia
Issue of 2024–12–15
forty-one papers selected by
Paolo Gallipoli, Barts Cancer Institute, Queen Mary University of London



  1. Am J Hematol. 2024 Dec 13.
      Patients with newly diagnosed acute myeloid leukemia (ND-AML) derive variable survival benefit from venetoclax + hypomethylating agent (Ven-HMA) therapy. The primary objective in the current study was to develop genetic risk models that are predictive of survival and are applicable at the time of diagnosis and after establishing treatment response. Among 400 ND-AML patients treated with Ven-HMA at the Mayo Clinic, 247 (62%) achieved complete remission with (CR) or without (CRi) count recovery. Multivariable analysis-derived hazard ratios (HR), including 1.8 for European LeukemiaNet (ELN) adverse karyotype, 4.7 for KMT2Ar, 1.7 for TP53MUT, 2.6 for KRAS MUT, and 2.1 for IDH2WT were applied to develop an HR-weighted risk model: low, intermediate, and high; respective median survival censored for allogeneic stem cell transplant (ASCT) (3-year survival) were "not reached" (67%), 19.1 (33%), and 7.1 months (0%). In patients achieving CR/CRi, adverse karyotype, KMT2Ar, KRASMUT, IDH2WT predicted inferior survival, allowing for a complementary response-stratified risk model. The model was externally validated and was shown to be superior to the ELN 2024 risk model (AIC 179 vs. 195 and AUC 0.77 vs. 0.69). Survival was inferior with failure to achieve CR/CRi or not receiving ASCT; 3-year survival for high-risk with or without ASCT was 42% versus 0% (p < 0.01); intermediate 72% versus 43% (p = 0.06); and low-risk 88% versus 78% (p = 0.53). The Mayo genetic risk models offer pre-treatment and response-based prognostic tools for ND-AML treated with Ven-HMA. The current study underscores the prognostically indispensable role of achieving CR/CRi and ASCT.
    Keywords:  karyotype; mutations; remission; survival; venetoclax
    DOI:  https://doi.org/10.1002/ajh.27564
  2. bioRxiv. 2024 Nov 26. pii: 2024.11.24.625107. [Epub ahead of print]
      Outcomes of relapsed/refractory acute myeloid leukemia (AML) are poor, and strategies to improve outcomes are urgently needed. One important factor promoting relapse and chemoresistance is the ability of AML cells to thrive in vivo within an intrinsically hypoxic bone marrow microenvironment. Here we show that human AML cells exhibit enhanced autophagy, specifically mitophagy (i.e., increased accumulation of mitochondria and decreased mitochondrial membrane potential) under hypoxia. To target this pathway, we investigated the activity of the potent chloroquine-derived autophagy inhibitor, Lys05, on human AML cells, patient samples, and patient derived xenograft models. Inhibition of autophagy by Lys05 in AML cells prevented removal of damaged mitochondria and preferentially enhanced cell death under hypoxia mirroring the marrow microenvironment. Lys05 eradicated human AML cells of all genotypes including p53 mutant cells. Lys05 treatment in primary AML xenografted mice decreased CD34+CD38- human cells and prolonged overall survival. Moreover, Lys05 overcame hypoxia-induced chemoresistance and improved the efficacy of cytarabine, venetoclax, and azacytidine in vitro and in vivo in AML models. Our results demonstrate the importance of autophagy, specifically mitophagy, as a critical survival and chemoresistance mechanism of AML cells under hypoxic marrow conditions. Therapeutic targeting of this pathway in future clinical studies for AML is warranted.
    DOI:  https://doi.org/10.1101/2024.11.24.625107
  3. Blood. 2024 Dec 09. pii: blood.2024025464. [Epub ahead of print]
      Patients with higher-risk myelodysplastic syndromes (HR MDS) have a median survival of ~1.5 years with azacitidine, and hematopoietic stem cell transplantation is their only curative option. Therefore, improved therapies are needed. This phase 1b study investigated safety and efficacy of venetoclax, a selective BCL-2 inhibitor, at the recommended phase 2 dose (RP2D: 400 mg for 14 days/28-day cycle), in combination with azacitidine (75 mg/m2 for 7 days/28-day cycle) for treatment-naive HR MDS (NCT02942290). Safety was the primary outcome, and complete remission (CR) rate was the primary efficacy outcome. Secondary outcomes included rates of modified overall response (mOR), hematologic improvement (HI), overall survival (OS), and time to next treatment (TTNT). As of May 2023, 107 patients received venetoclax and azacitidine combination at the RP2D. Best response of CR or marrow CR was observed in 29.9% and 50.5% of patients (mOR, 80.4%). Median OS was 26.0 months, with 1-year and 2-year survival estimates of 71.2% and 51.3%, respectively. Of 59 patients who were red blood cell and/or platelet transfusion-dependent at baseline, 24 (40.7%) became transfusion-independent on study, including 11 (18.6%) who also achieved CR. Fifty-one (49.0%) of 104 evaluable patients achieved HI. Median TTNT excluding transplantation was 13.4 months. Adverse events reflected known safety profiles for venetoclax and azacitidine, including constipation (53.3%), nausea (49.5%), neutropenia (48.6%), thrombocytopenia (44.9%), febrile neutropenia (42.1%), and diarrhea (41.1%). Overall, venetoclax plus azacitidine at the RP2D was well tolerated and had favorable outcomes. A phase 3 study (NCT04401748) is ongoing to confirm survival benefit of this combination.
    DOI:  https://doi.org/10.1182/blood.2024025464
  4. Haematologica. 2024 Dec 12.
      In myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) with TP53 aberrations, dissecting the interaction amongst patient, disease and treatment factors are important for therapeutic decisions and prognostication. This retrospective analysis included patients with newly diagnosed MDS (>5% blasts) and AML with TP53 mutation(s) treated at MD Anderson Cancer Center. We factored patient age, TP53 aberration burden, therapy intensity and use of venetoclax in the AML subgroup, and allogeneic hematopoietic stem cell transplantation (HSCT) to interrogate outcomes. TP53 was annotated as high-risk (TP53HR) if >1 mutation, one mutation + allelic deletion or a single mutation with variant allele frequency (VAF) ≥40%; TP53 low risk (TP53LR) included a single TP53 mutation VAF.
    DOI:  https://doi.org/10.3324/haematol.2024.286465
  5. Leukemia. 2024 Dec 12.
      Lack of HLA-matched related/unrelated donor remains a barrier to allogeneic hematopoietic cell transplantation (HCT) for adult acute myeloid leukemia (AML), with ongoing uncertainty about optimal donor type if more than one alternative donor is available. To assess the relationship between donor type, pre-HCT measurable residual disease (MRD), and post-HCT outcomes, we retrospectively analyzed 1265 myelodysplastic neoplasm (MDS)/AML and AML patients allografted in first or second remission with an HLA-matched sibling (MSD) or unrelated donor (MUD), HLA-mismatched unrelated donor (MMD), an HLA-haploidentical donor, or umbilical cord blood (UCB) at a single institution. Relapse risk was non-significantly higher after HLA-haploidentical and lower after UCB HCT. Non-relapse mortality (NRM) was significantly higher in patients undergoing MMD HCT, HLA-haploidentical HCT, and UCB, translating into significantly lower relapse-free survival (RFS) and overall survival for MMD and HLA-haploidentical HCT. There was a significant interaction between conditioning intensity and post-HCT outcomes for UCB HCT with better RFS for UCB HCT after MAC but higher NRM after non-MAC. In patients with pre-HCT MRD receiving MAC, relapse risk was significantly lower and RFS higher in those who underwent UCB HCT in comparison to MSD/MUD. Together, UCB HCT is a valuable alternative for MAC HCT, particularly in patients with pre-HCT MRD.
    DOI:  https://doi.org/10.1038/s41375-024-02497-z
  6. CA Cancer J Clin. 2024 Dec 10.
      The first 5 decades of research in acute myeloid leukemia (AML) were dominated by the cytarabine plus anthracyclines backbone, with advances in strategies including allogeneic hematopoietic stem cell transplantation, high-dose cytarabine, supportive care measures, and targeted therapies for the subset of patients with acute promyelocytic leukemia. Since 2017, a turning point in AML research, 12 agents have received regulatory approval for AML in the United States: venetoclax (BCL2 inhibitor); gemtuzumab ozogamicin (CD33 antibody-drug conjugate); midostaurin, gilteritinib, and quizartinib (fms-like tyrosine kinase 3 inhibitors); ivosidenib, olutasidenib, and enasidenib (isocitrate dehydrogenase 1 and 2 inhibitors); oral azacitidine (a partially absorbable formulation); CPX351 (liposomal encapsulation of cytarabine:daunorubicin at a molar ratio of 5:1); glasdegib (hedgehog inhibitor); and recently revumenib (menin inhibitor; approved November 2024). Oral decitabine-cedazuridine, which is approved as a bioequivalent alternative to parenteral hypomethylating agents in myelodysplastic syndrome, can be used for the same purpose in AML. Menin inhibitors, CD123 antibody-drug conjugates, and other antibodies targeting CD123, CD33, and other surface markers are showing promising results. Herein, the authors review the frontline and later line therapies in AML and discuss important research directions.
    Keywords:  acute myeloid leukemia; acute promyelocytic leukemia; antibody–drug conjugate; measurable residual disease
    DOI:  https://doi.org/10.3322/caac.21873
  7. Cancer Res Commun. 2024 Dec 12.
      Tuspetinib (TUS) is a well-tolerated, once daily, oral kinase inhibitor in clinical development for treatment of AML. Nonclinical studies show that TUS targets key pro-survival kinases with IC50 values in the low nM range, including SYK, wildtype and mutant forms of FLT3, mutant but not wildtype forms of KIT, RSK2 and TAK1-TAB1 kinases, and indirectly suppresses expression of MCL1. Oral TUS markedly extended survival in subcutaneously and orthotopically inoculated xenograft models of FLT3 mutant human AML, was well tolerated, and delivered enhanced activity when combined with venetoclax or 5-azacytidine. In vitro, TUS demonstrated potent killing of AML lines (GI50 = 1.3 to 5.2 nM) and Ba/F3 cells expressing wildtype (GI50 = 9.1 nM) or various mutant forms of FLT3 (GI50 = 2.5 - 56 nM). In AML lines, the multi-kinase targeting capacity of TUS suppressed phosphorylation of SYK, FLT3, STAT5, MEK, ERK, AKT, mTOR, 4E-BP1 and S6K kinases. Cells selected for stable acquired resistance to TUS exhibited increased BAX and hypersensitivity to venetoclax (1900-fold), navitoclax and MCL1 inhibitors. MV-4-11 FLT3-ITD clones expressing NRASG12D revealed that high-level expression of NRASG12D generated modest resistance to TUS and greater resistance to venetoclax (VEN), yet the TUS/VEN combination exhibited synergy in NRASG12D AML model. Favorable preclinical safety and pharmacology properties, the efficacy of the TUS/VEN combination in a murine model, and the synthetic lethal vulnerability to VEN that accompanies TUS resistance provide the basis for exploration of the TUS/VEN combination in patients with relapsed or refractory AML.
    DOI:  https://doi.org/10.1158/2767-9764.CRC-24-0258
  8. Am J Hematol. 2024 Dec 12.
      
    Keywords:  GVHD; HSCT; myelofibrosis; ruxolitinib; splenectomy
    DOI:  https://doi.org/10.1002/ajh.27559
  9. Blood. 2024 Dec 09. pii: blood.2022019306. [Epub ahead of print]
      Initial clinical trials with drugs targeting epigenetic modulators - such as bromodomain and extraterminal protein (BET) inhibitors - demonstrate modest results in acute myeloid leukemia (AML). A major reason for this involves an increased transcriptional plasticity within AML, which allows cells to escape the therapeutic pressure. In this study, we investigated immediate epigenetic and transcriptional responses following BET inhibition and could demonstrate that BET inhibitor-mediated release of BRD4 from chromatin is accompanied by an acute compensatory feedback that attenuates down-regulation, or even increases expression, of specific transcriptional modules. This adaptation is marked at key AML maintenance genes and is mediated by p300, suggesting a rational therapeutic opportunity to improve outcomes by combining BET- and p300- inhibition. p300 activity is required during all steps of resistance adaptation, however, the specific transcriptional programs that p300 regulates to induce resistance to BET inhibition differ in part between AML subtypes. As a consequence, in some AMLs the requirement for p300 is highest during earlier stages of resistance to BET inhibition, where p300 regulates transitional transcriptional patterns that allow leukemia-homeostatic adjustments. In other AMLs, p300 shapes a linear resistance to BET inhibition and remains crucial throughout all stages of the evolution of resistance. Altogether, our study elucidates the mechanisms that underlie an "acute" state of resistance to BET inhibition, achieved through p300 activity, and how these mechanisms remodel to mediate "chronic" resistance. Importantly, our data also suggest that sequential treatment with BET- and p300-inhibition may prevent resistance development, thereby improving outcomes.
    DOI:  https://doi.org/10.1182/blood.2022019306
  10. Nat Cardiovasc Res. 2024 Dec;3(12): 1568-1583
      Certain somatic mutations provide a fitness advantage to hematopoietic stem cells and lead to clonal expansion of mutant blood cells, known as clonal hematopoiesis (CH). Among the most common CH mutations, ASXL1 mutations pose the highest risk for cardiovascular diseases (CVDs), yet the mechanisms by which they contribute to CVDs are unclear. Here we show that hematopoietic cells harboring C-terminally truncated ASXL1 mutant (ASXL1-MT) accelerate the development of atherosclerosis in Ldlr-/- mice. Transcriptome analyses of plaque cells showed that monocytes and macrophages expressing ASXL1-MT exhibit inflammatory signatures. Mechanistically, we demonstrate that wild-type ASXL1 has an unexpected non-epigenetic role by suppressing innate immune signaling through the inhibition of IRAK1-TAK1 interaction in the cytoplasm. This regulatory function is lost in ASXL1-MT, resulting in NF-κB activation. Inhibition of IRAK1/4 alleviated atherosclerosis driven by ASXL1-MT and decreased inflammatory monocytes. The present work provides a mechanistic and cellular explanation linking ASXL1 mutations, CH and CVDs.
    DOI:  https://doi.org/10.1038/s44161-024-00579-w
  11. Hematology Am Soc Hematol Educ Program. 2024 12 06. 2024(1): 150-157
      Measurable residual disease (MRD) is a strong but imprecise predictor of relapse in acute myeloid leukemia. Many patients fall into the outlier categories of MRD positivity without relapse or MRD negativity with relapse. Why? We will discuss these states in the context of "clonal ontogeny" examining how mutations, clonal structure, and Darwinian rules impact response, resistance, and relapse.
    DOI:  https://doi.org/10.1182/hematology.2024000541
  12. Hematology Am Soc Hematol Educ Program. 2024 12 06. 2024(1): 321-325
      TP53 is mutated in 10 to 15% of cases of acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) and is associated with a previous exposure to cytotoxic therapy, complex cytogenetic abnormalities, and a poor prognosis. Recent data have established the importance of TP53-mutant allele status, the determination of which requires specific genetic testing. Compared with monoallelic disease, multihit TP53-mutant AML/MDS is associated with chromosomal abnormalities and decreased overall survival. Most TP53 mutations are missense mutations that localize to the DNA binding domain. Hot-spot mutations involving residues R175, Y220, G245, R248, R273, or R282 represent approximately 35% of all TP53 missense mutations in AML/MDS. There is evidence that these hot-spot mutations may have dominant negative or gain-of-function properties. Here we review this evidence and discuss its potential impact on patient outcomes and clinical management.
    DOI:  https://doi.org/10.1182/hematology.2024000556
  13. bioRxiv. 2024 Nov 27. pii: 2024.11.27.625734. [Epub ahead of print]
      Somatic mutations in hematopoietic stem/progenitor cells (HSPCs) can lead to clonal hematopoiesis of indeterminate potential (CHIP), potentially progressing to myelodysplastic syndromes (MDS). Here, we investigated how CHIP and MDS remodel the human bone marrow (BM) niche relative to healthy elderly donors, using single cell and anatomical analyses in a large BM cohort. We found distinct inflammatory remodeling of the BM in CHIP and MDS. Furthermore, the stromal compartment progressively lost its HSPC-supportive adipogenic CXCL12-abundant reticular cells while an inflammatory mesenchymal stroma cell (iMSCs) population emerged in CHIP, which expanded in MDS. iMSCs exhibited distinct functional signatures in CHIP and MDS, retaining residual HSPC-support and angiogenic activity in MDS, corresponding with an increase in microvasculature in the MDS niche. Additionally, an IFN-responsive T cell population was linked to fueling inflammation in the stroma. Overall, these findings open new avenues for early intervention in hematological malignancies.
    DOI:  https://doi.org/10.1101/2024.11.27.625734
  14. Br J Haematol. 2024 Dec 09.
      The age-associated mutational state of clonal haematopoiesis (CH) is linked to multiple adverse health outcomes. As higher risk CH can lead to progressive neoplastic or vascular disease, there is interest in developing clinical trials to mitigate risk associated with CH. Given the high prevalence of CH, data from clinical trials could have broad public health implications for screening and therapy. Thoughtful consideration is needed to design trials that are both clinically relevant and avoid overmedicalization. Here, we summarize clinical studies of CH to date and provide suggestions and guidance on how to approach designing CH-focused therapeutic clinical trials. These recommendations are derived from discussions among clinical researchers and scientists emanating from the Inaugural Meeting on Somatic Mutations and Predisease in October 2021.
    Keywords:  clinical trials; clonal cytopenias; clonal hematopoiesis; therapy
    DOI:  https://doi.org/10.1111/bjh.19925
  15. Blood. 2024 Dec 11. pii: blood.2024025618. [Epub ahead of print]
      Pediatric acute myeloid leukemia (pAML) is a clonal disease with recurrent genetic alterations that affect epigenetic states. However, the implications of epigenetic dysregulation in disease progression remain unclear. Here, we interrogated single-cell and clonal level chromatin accessibility of bone marrow samples from 28 pAML patients representing multiple subtypes using mtscATAC-seq, which revealed distinct differentiation hierarchies and abnormal chromatin accessibility in a subtype-specific manner. Innate immune signaling was commonly enhanced across subtypes and related to improved advantage of clonal competition and unfavorable prognosis, with further reinforcement in a relapse-associated leukemia stem cell-like population. We identified a panel of 31 innate immunity related genes to improve the risk classification of pAML patients. By comparing paired diagnosis and post-chemotherapy relapse samples, we showed that primitive cells significantly reduced MHC class II signaling, suggesting an immune evasion mechanism to facilitate their expansion at relapse. Key regulators orchestrating cell cycle dysregulation were identified to contribute to pAML relapse in drug-resistant clones. Our work establishes the single-cell chromatin accessibility landscape at clonal resolution and reveals the critical involvement of epigenetic disruption, offering insights into classification and targeted therapies of pAML patients.
    DOI:  https://doi.org/10.1182/blood.2024025618
  16. Am J Hematol. 2024 Dec 10.
      Samples from 34 adult patients newly diagnosed with core binding factor leukemia (CBFL) were collected both at the time of diagnosis and at relapse and were centrally analyzed. Eligible patients received either standard induction CT known as "3 + 7" or an equivalent regimen, according to the recruiting center's policy. Patients who achieved CR or CRi received 3 courses of high-dose ARA-C (Cytarabine) 3000 mg/m2 every 12 h on days 1, 3, and 5, along with midostaurin at the dose of 50 mg b.i.d from Day 8 to Day 21 as part of consolidation therapy. Following the completion of the consolidation phase, patients received midostaurin as a monotherapy at the dose of 50 mg b.i.d. for 1 year as continuation therapy. The CR rate was 97%; we recorded an OS rate of 73.52% and a DFS rate of 48.4% for the entire cohort. The RI was 38.8% in the CBFB::MYH11 and 66.6% in the RUNX1::RUNX1T1 group. MRD (Measurable Residual Disease) was assessed by RQ-PCR at 10 time points throughout the study, as indicated by arrows.
    Keywords:  AML; FLT3; KIT; core‐binding factor leukemia; midostaurin
    DOI:  https://doi.org/10.1002/ajh.27547
  17. Br J Haematol. 2024 Dec 09.
      'As our understanding of the biology of clonal hematopoiesis expands, a pressing need in the field becomes the design and implementation of clinical trials to help mitigate the risk for progression to overt myeloid neoplasm. Effective clinical trial design will be informed by use of personalized genetic risk to determine eligibility, strategic endpoint selection, and identification of suitable interventions with a goldilocks balance of toxicity and reduced risk of progression. We will only reach this milestone through collaboration'. Commentary on: Haque et al. A blueprint for pursuing therapeutic interventions and early phase clinical trials in clonal haematopoiesis. Br J Haematol 2024 (Online ahead of print). doi: 10.1111/bjh.19925.
    Keywords:  clonal hematopoiesis; myeloid neoplasia; overt myeloid neoplasm
    DOI:  https://doi.org/10.1111/bjh.19948
  18. Cell Stem Cell. 2024 Dec 11. pii: S1934-5909(24)00400-4. [Epub ahead of print]
      Gene editing the BCL11A erythroid enhancer is a validated approach to fetal hemoglobin (HbF) induction for β-hemoglobinopathy therapy, though heterogeneity in edit allele distribution and HbF response may impact its safety and efficacy. Here, we compare combined CRISPR-Cas9 editing of the BCL11A +58 and +55 enhancers with leading gene modification approaches under clinical investigation. Dual targeting of the BCL11A +58 and +55 enhancers with 3xNLS-SpCas9 and two single guide RNAs (sgRNAs) resulted in superior HbF induction, including in sickle cell disease (SCD) patient xenografts, attributable to simultaneous disruption of core half E-box/GATA motifs at both enhancers. Unintended on-target outcomes of double-strand break (DSB) repair in hematopoietic stem and progenitor cells (HSPCs), such as long deletions and centromere-distal chromosome fragment loss, are a byproduct of cellular proliferation stimulated by ex vivo culture. Editing quiescent HSPCs bypasses long deletion and micronuclei formation and preserves efficient on-target editing and engraftment function.
    Keywords:  BCL11A; enhancers; fetal hemoglobin; genotoxicity; hematopoietic stem cells; sickle cell disease; therapeutic gene editing
    DOI:  https://doi.org/10.1016/j.stem.2024.11.001
  19. bioRxiv. 2024 Nov 27. pii: 2024.11.25.625252. [Epub ahead of print]
      Hematopoietic stem cells (HSCs) responsible for blood cell production and their bone marrow regulatory niches undergo age-related changes, impacting immune responses and predisposing individuals to hematologic malignancies. Here, we show that the age-related alterations of the megakaryocytic niche and associated downregulation of Platelet Factor 4 (PF4) are pivotal mechanisms driving HSC aging. PF4-deficient mice display several phenotypes reminiscent of accelerated HSC aging, including lymphopenia, increased myeloid output, and DNA damage, mimicking physiologically aged HSCs. Remarkably, recombinant PF4 administration restored old HSCs to youthful functional phenotypes characterized by improved cell polarity, reduced DNA damage, enhanced in vivo reconstitution capacity, and balanced lineage output. Mechanistically, we identified LDLR and CXCR3 as the HSC receptors transmitting the PF4 signal, with double knockout mice showing exacerbated HSC aging phenotypes similar to PF4-deficient mice. Furthermore, human HSCs across various age groups also respond to the youthful PF4 signaling, highlighting its potential for rejuvenating aged hematopoietic systems. These findings pave the way for targeted therapies aimed at reversing age-related HSC decline with potential implications in the prevention or improvement of the course of age-related hematopoietic diseases.
    Key Points: Age-related attrition of the megakaryocytic niche and associated PF4 downregulation is a central mechanism in HSC aging.PF4 supplementation, acting on LDLR and CXCR3 receptors, rejuvenates the function of aged HSCs.
    DOI:  https://doi.org/10.1101/2024.11.25.625252
  20. N Engl J Med. 2024 Dec 12. pii: 10.1056/NEJMc2412813#sa3. [Epub ahead of print]391(23): 2275-2276
      
    DOI:  https://doi.org/10.1056/NEJMc2412813
  21. Hematology Am Soc Hematol Educ Program. 2024 12 06. 2024(1): 158-167
      Acute myeloid leukemia (AML) is classified by risk groups according to a number of genetic mutations, which may occur alone or in combination with other mutations and chromosomal abnormalities. Prognosis and appropriate therapy can vary significantly based on a patient's genetic risk group, making mutation-informed decisions crucial to successful management. However, the presence of measurable residual disease (MRD) after induction and consolidation therapy, before hematopoietic cell transplant, and during posttransplant monitoring can be even more significant to patient prognosis than their genetic subtype. Clinicians must select MRD-monitoring methods most appropriate for a patient's genetic profile and a treatment regimen that considers both a patient's primary genetic subgroup and other risk factors, including MRD information. Recent clinical trial data and drug approvals, together with advances in the validation of MRD using next-generation sequencing, require a deeper understanding of the complex AML mutation and MRD matrix, enabling more insightful monitoring and treatment decisions for intensively treated AML patients. Here, we provide an overview on methods and clinical consequences of MRD monitoring in genetic subgroups of patients with AML. As treatment options become more personalized, on-treatment MRD monitoring will become even more important to effective AML care.
    DOI:  https://doi.org/10.1182/hematology.2024000542
  22. Hemasphere. 2024 Dec;8(12): e70056
      Myelofibrosis (MF) is a clonal myeloid neoplasm characterized by bone marrow fibrosis, splenomegaly, and disease-associated symptoms, as well as increased mortality, due to thrombosis, severe bleeding, infections, or progression to acute leukemia. Currently, the management of MF patients is tailored according to risk scores, with higher-risk (intermediate-2 and high-risk) patients being assessed for allogeneic stem cell transplantation, which remains the only potentially curative treatment option. On the other hand, lower risk (low- and intermediate-1 risk) patients who are symptomatic may be treated with JAK inhibitors or other drugs. However, none of these drug treatments have induced relevant rates of durable complete remissions, and, therefore, novel treatments are needed to improve the long-term outcomes of MF patients. This review summarizes current preclinical and clinical approaches to MF therapy, including novel drug combinations involving JAK inhibitors and innovative monotherapies. These drugs target transcription, nuclear export, survival pathways, or various intracellular pathways, ranging from JAK-STAT signaling to PI3-Kinase, TP53, PIM1, or S100A8/A9/toll-like receptor pathways. Also, extracellular targeting using interferon, calreticulin mutant-specific antibodies, and other immunotherapeutic approaches are discussed, as well as various antifibrotic strategies. In addition, preclinical approaches that target individual mutated clones, for example, by mutation-specific JAK2V617F inhibitors or DNA repair pathway inhibitors, are presented. Finally, current efforts of generating novel endpoints for clinical trials aim more at disease modification and overall survival than at improvements of splenomegaly or symptoms. Together, the new generations of clinical trials promise to offer substantial improvements in the management of MF patients and long-term disease control.
    DOI:  https://doi.org/10.1002/hem3.70056
  23. N Engl J Med. 2024 Dec 12. pii: 10.1056/NEJMc2412813#sa1. [Epub ahead of print]391(23): 2274-2275
      
    DOI:  https://doi.org/10.1056/NEJMc2412813
  24. Hematology Am Soc Hematol Educ Program. 2024 12 06. 2024(1): 326-334
      TP53-mutated myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) remain a challenging spectrum of clonal myeloid disease with poor prognosis. Recent studies have shown that in AML, MDS, and MDS/AML with biallelic TP53 loss, the TP53-mutated clone becomes dominant. These are highly aggressive diseases that are resistant to most chemotherapies. The latest 2022 International Consensus Classification categorizes these diseases under "myeloid disease with mutated TP53." All treatment approaches have not improved survival rates for this disease. Many newer therapies are on the horizon, including chimeric antigen receptor T/NK-cell therapies, mutated p53 reactivators, Fc fusion protein, and monoclonal antibodies targeting various myeloid antigens. This review summarizes the current approaches for myeloid disease with TP53 mutation and provides an overview of emerging nontransplant approaches.
    DOI:  https://doi.org/10.1182/hematology.2024000557
  25. N Engl J Med. 2024 Dec 12. pii: 10.1056/NEJMc2412813#sa2. [Epub ahead of print]391(23): 2275
      
    DOI:  https://doi.org/10.1056/NEJMc2412813
  26. Cell Stem Cell. 2024 Dec 05. pii: S1934-5909(24)00376-X. [Epub ahead of print]
      Editing the +58 region of the BCL11A erythroid enhancer has shown promise in treating β-globin disorders. To address variations in fetal hemoglobin (HbF) response, we investigated editing both +58 and +55 enhancers. Rhesus macaques transplanted with edited hematopoietic stem/progenitor cells (HSPCs) following busulfan conditioning exhibited durable, high-level (∼90%) editing frequencies post transplantation with sustained HbF reactivation over 4 years, without hematological perturbations. HbF levels were further boosted by stress erythropoiesis or hydroxyurea. Bone marrow analysis revealed that gene edits were predominantly programmed deletions, programmed inversions, and short indels, each disrupting the enhancer core TGN7-9WGATAR half E-box/GATA binding motifs. Nonprogrammed long deletions were disfavored in engrafting cells. CD45 antibody-drug conjugate (ADC) conditioning achieved comparable engraftment and HbF reactivation, whereas lentiviral vector tracking showed polyclonal reconstitution with dynamics similar to animals conditioned with total body irradiation (TBI) or busulfan. Joining CD45-ADC conditioning with combined enhancer editing presents an effective strategy for β-hemoglobinopathies, enabling durable HbF reactivation without chemotherapy.
    Keywords:  CRISPR-Cas9; HSC transplantation; antibody conditioning; busulfan; fetal hemoglobin; hydroxyurea; sickle cell disease; therapeutic gene editing; β-globin disorders; γ-globin
    DOI:  https://doi.org/10.1016/j.stem.2024.10.014
  27. Hematology Am Soc Hematol Educ Program. 2024 12 06. 2024(1): 168-177
      The ongoing development of molecularly targeted therapies in addition to the new standard of care combination of azacitidine and venetoclax (AZA-VEN) has transformed the prognostic outlook for older, transplant-ineligible patients with acute myeloid leukemia (AML). While conventional treatments, such as standard anthracycline and cytarabine- based chemotherapy or hypomethylating agent (HMA) monotherapy, are associated with a generally poor prognosis in this patient population, the use of these novel regimens can result in long-lasting, durable remissions in select patient subgroups. Furthermore, the simultaneous discovery of resistance mechanisms to targeted therapies and AZA-VEN has enabled the identification of patient subgroups with inferior outcomes, leading to the development, of new risk-stratification models and clinical investigations incorporating targeted therapies using an HMA-VEN-based platform. Treatments inclusive of IDH1, IDH2, FLT3, and menin inhibitors combined with HMA-VEN have additionally demonstrated safety and high rates of efficacy in early-phase clinical trials, suggesting these regimens may further improve outcomes within select subgroups of patients with AML in the near future. Additional studies defining the prognostic role of measurable residual disease following VEN-based treatment have further advanced prognostication capabilities and increased the ability for close disease monitoring and early targeted intervention prior to morphologic relapse. This review summarizes these recent developments and their impact on the treatment and survival of transplant-ineligible patients living with AML.
    DOI:  https://doi.org/10.1182/hematology.2024000540
  28. N Engl J Med. 2024 Dec 12. pii: 10.1056/NEJMc2412813#sa4. [Epub ahead of print]391(23): 2276
      
    DOI:  https://doi.org/10.1056/NEJMc2412813
  29. Transplant Cell Ther. 2024 Nov 26. pii: S2666-6367(24)00730-9. [Epub ahead of print]
       BACKGROUND: The standard treatment for acute graft-vs-host disease (GVHD), a common complication following allogeneic hematopoietic cell transplant, remains prolonged courses of high dose corticosteroids. Previous attempts to decrease corticosteroid exposure during GVHD therapy failed because physicians lack the tools necessary to safely reduce and shorten therapy and fear loss of GVHD control in responding patients. Prior studies have shown that a serum biomarker risk score, the MAGIC algorithm probability (MAP), provided prognostic value within groups with similar clinical severity and that patients with GVHD that is Minnesota standard risk by clinical symptoms and who have a low MAP at the start of corticosteroid treatment represent a low risk group with good outcomes.
    OBJECTIVE: This study tested the hypothesis that serial monitoring of GVHD symptoms and the MAP score in patients with low risk GVHD could provide further risk stratification, and would identify a subset with exceptionally low rates of failure with standard treatment, which we term ultra-low risk (ULR) GVHD who might benefit from reduced corticosteroid treatment.
    STUDY DESIGN: Weekly monitoring of clinical symptoms and MAPs from initiation to day 14 of treatment was used to further divide 450 patients with low risk GVHD into groups with different outcomes, such as overall response rates at day 28 and non-relapse mortality at six-months.
    RESULTS: 310/450 low risk patients (69%) who achieved clinical response by day 14 and had low MAPs at days 7 and 14 constituted an ultra-low risk (ULR) group. that experienced a significantly higher overall response rate at day 28 (93% vs 50%, p<0.001) that was sustained to day 56 (84% vs 45%, p<0.001) and significantly lower six-month NRM (4% vs 13%, p<0.001) compared to the non-ULR patients. Patients who achieved clinical response by day 14 but who developed a high MAP during monitoring (n=20) experienced six-fold higher six-month NRM than the ULR group (25% vs 4%, p<0.001). Among 120 patients who did not achieve a clinical response by day 14, the overwhelming majority (n=112) who maintained low MAPs at both days 7 and 14 of treatment experienced six-fold lower NRM at six months compared to patients with a high MAP at either time point (8% vs 50%, p<0.001). The majority of deaths within the ULR group were due to infections in patients with complete and sustained control of GVHD symptoms while the majority of deaths in the non-ULR group were due to poorly controlled GVHD.
    CONCLUSIONS: Serial monitoring during treatment can identify a large subset of patients by day 14 who achieve excellent GVHD control but remain at risk for treatment complications with standard treatment and who might be suitable candidates for testing abbreviated corticosteroid courses.
    Keywords:  Acute GVHD; Biomarker; Immunosuppression; Treatment
    DOI:  https://doi.org/10.1016/j.jtct.2024.10.012
  30. Blood Cancer Discov. 2024 Dec 09.
      Transformative technologies to sequence tumor genomes at large scale and single-cell resolution have exposed the repertoire of genetic alterations that are present in leukemia genomes, the timing of their acquisition and patterns of their co-occurrence. In parallel, single-cell multi-omics technologies are allowing us to map the differentiation paths and hierarchical structures of malignant cells and giving us a glimpse into hematopoietic development in prenatal life. We propose that interrogating how the genetic evolution, differentiation hierarchy and ontogeny of malignant myeloid cells intersect with each other, using new experimental systems and multimodal technologies, will fuel the next generation of research breakthroughs.
    DOI:  https://doi.org/10.1158/2643-3230.BCD-24-0235
  31. Hematology Am Soc Hematol Educ Program. 2024 12 06. 2024(1): 535-540
      Interferon alpha (IFN-α) is a fascinating molecule with many biological properties yet to be fully understood. Among these properties, several have demonstrated usefulness for targeting malignant cells, including hematopoietic cells from patients with myeloproliferative neoplasms. Indeed, IFN-α has been used for decades across all myeloproliferative neoplasms, but only recently a new form, ropegIFN-α2b, was approved to treat patients with polycythemia vera. Many phase 2 and more recently phase 3 studies have demonstrated IFN-α's promise in treating patients with essential thrombocythemia and early-stage myelofibrosis. In addition, although not approved in that situation, IFN-α is the only cytoreductive therapy that can be used during pregnancy. Today, IFN-α is a key medicine for polycythemia vera and essential thrombocythemia, while its place in the management of myelofibrosis must be better defined. The advantages of IFN therapy include a well-known safety profile, high rates of clinical and molecular responses, and a unique ability to deeply reduce the mutant allele burden of most of the driver mutations causing myeloproliferative neoplasms. Recent preliminary data from prospective studies suggest that molecular responses may be correlated with prolonged event-free survival, raising the hope that IFN therapy may ultimately alter the natural history of many diseases.
    DOI:  https://doi.org/10.1182/hematology.2024000577
  32. Hematology Am Soc Hematol Educ Program. 2024 12 06. 2024(1): 524-534
      Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs) are a group of blood cancers that result from somatic mutations in hematopoietic stem cells, causing constitutive activation of JAK-STAT signaling pathways with consequent overproduction of 1 or more myeloid lineages. The initiating event in MPN pathogenesis is a genetic mutation, and consequently molecular profiling is central to the diagnosis, risk stratification, and, increasingly, monitoring of therapy response in persons with MPN. In this review we summarize current approaches to molecular profiling of classical MPNs (essential thrombocythemia, polycythemia vera, and myelofibrosis), using illustrative clinical case histories to demonstrate how genetic analysis is already fully integrated into MPN diagnostic classification and prognostic risk stratification. Molecular profiling can also be used in MPN to measure response to therapy both in clinical trials and increasingly in routine clinical practice. Taking a forward look, we discuss how molecular profiling in MPN might be used in the future to select specific molecularly targeted therapies and the role of additional genetic methodologies beyond mutation analysis.
    DOI:  https://doi.org/10.1182/hematology.2024000576
  33. Life Sci. 2024 Dec 05. pii: S0024-3205(24)00887-7. [Epub ahead of print] 123297
      Chemotherapy resistance is a significant clinical challenge in the treatment of leukemia. M2 macrophages have been identified as key contributors to the development of chemotherapy resistance in cancer, yet the precise mechanisms by which macrophages regulate this resistance remain elusive. Our study has identified CCL20 as a pivotal factor in the promotion of chemoresistance in AML cells by M2 macrophages. The chemotherapeutic agent daunorubicin induces a marked increase in ROS and lipid peroxidation levels within AML cells. This is accompanied by the inhibition of the SLC7A11/GCL/GPX4 signaling axis, elevated levels of intracellular free iron, disrupted iron metabolism, and consequent mitochondrial damage, ultimately leading to ferroptosis. Notably, CCL20 enhances the ability of AML cells to maintain iron homeostasis by upregulating SLC7A11 protein activity, mitigating mitochondrial damage, and inhibiting ferroptosis, thereby contributing to chemotherapy resistance. Furthermore, in vivo experiments demonstrated that blocking CCL20 effectively restores the sensitivity of AML cells to daunorubicin chemotherapy. Collectively, these findings underscore the complex interplay between M2 macrophages, CCL20 signaling, and chemotherapy resistance in AML, highlighting potential therapeutic avenues for intervention.
    Keywords:  Acute myeloid leukemia; CCL20; Chemoresistance; Ferroptosis; Macrophages
    DOI:  https://doi.org/10.1016/j.lfs.2024.123297
  34. Lancet Haematol. 2024 Dec 03. pii: S2352-3026(24)00317-X. [Epub ahead of print]
    TREATT Trial Investigators
       BACKGROUND: Bleeding is common in patients with haematological malignancies undergoing intensive therapy. We aimed to assess the effect of tranexamic acid on preventing bleeding and the need for platelet transfusions.
    METHODS: TREATT was an international, randomised, double-blind, parallel, phase 3 superiority trial conducted at 27 haematology centres in Australia and the UK. We enrolled adults (aged ≥18 years) receiving intensive chemotherapy or haematopoietic stem-cell transplantation for a haematological malignancy, with a platelet count of 10 × 109 platelets per L or less for 5 days or longer. Patients were randomly assigned (1:1) using block randomisation, stratified by site, to tranexamic acid (1 g every 8 h intravenously or 1·5g every 8 h orally) or placebo when their platelet count was less than 30 × 109 platelets per L. Treatment was continued until platelet recovery or day 30. Prophylactic platelet transfusions were maintained as standard of care. The primary endpoint was the proportion of patients who died or had WHO grade 2 or higher bleeding up to day 30. A modified intention-to-treat population including randomly assigned patients whose platelet count decreased to 30 × 109 platelets per L or less was used for analysis. This trial is registered with ClinicalTrials.gov (NCT03136445), ISRCTN (ISRCTN73545489), and the European Clinical Trials Register (EudraCT 2014-001513-35).
    FINDINGS: Between June 23, 2015, and Feb 17, 2022, 1736 patients were screened for eligibility, 616 of whom were enrolled and randomly assigned (310 to tranexamic acid and 306 to placebo). 19 participants were excluded from the modified intention-to-treat analysis, leaving 300 participants in the tranexamic acid group and 297 in the placebo group. Participant median age was 58 years (IQR 49-65), 380 (62%) of 616 participants were male, and 235 (38%) were female. The proportion of participants who died or had WHO grade 2 or higher bleeding was 31·7% (90/298 [95% CI 26·6-37·4]) in the tranexamic acid group and 34·2% (98/295 [29·0-40·0]) in the placebo group (hazard ratio 0·92 [95% CI 0·67-1·27]; p=0·62). There were no differences in thrombotic events or veno-occlusive disease. 94 serious adverse events in 77 participants were reported up to day 60 in the tranexamic acid group and 103 events in 82 participants in the placebo group.
    INTERPRETATION: There is insufficient evidence to support routine use of tranexamic acid to reduce bleeding in patients with haematological malignancies undergoing intensive chemotherapy.
    FUNDING: UK National Health Service Blood and Transplant and Australian National Health and Medical Research Council.
    DOI:  https://doi.org/10.1016/S2352-3026(24)00317-X
  35. Lancet. 2024 Dec 03. pii: S0140-6736(24)01880-4. [Epub ahead of print]
    FANCOLEN-1 gene therapy investigators
       BACKGROUND: Allogeneic haematopoietic stem-cell transplantation is the standard treatment for bone marrow failure (BMF) in patients with Fanconi anaemia, but transplantation-associated complications such as an increased incidence of subsequent cancer are frequent. The aim of this study was to evaluate the safety and efficacy of the infusion of autologous gene-corrected haematopoietic stem cells as an alternative therapy for these patients.
    METHODS: This was an open-label, investigator-initiated phase 1/2 clinical trial (FANCOLEN-1) and long-term follow-up trial (up to 7 years post-treatment) in Spain. Mobilised peripheral blood (PB) CD34+ cells from nine patients with Fanconi anaemia-A in the early stages of BMF were transduced with a therapeutic FANCA-encoding lentiviral vector and re-infused without any cytotoxic conditioning treatment. The primary efficacy endpoint of FANCOLEN-1 was the engraftment of transduced cells, as defined by the detection of at least 0·1 therapeutic vector copies per nucleated cell of patient bone marrow (BM) or PB at the second year post-infusion, without this percentage having declined substantially over the previous year. The safety coprimary endpoint was adverse events during the 3 years after infusion. The completed open-label phase 1/2 and the ongoing long-term clinical trials are registered with ClinicalTrials.gov, NCT03157804; EudraCT, 2011-006100-12; and NCT04437771, respectively.
    FINDINGS: There were eight evaluable treated patients with Fanconi anaemia-A. Patients were recruited between Jan 7, 2016 and April 3, 2019. The primary endpoint was met in five of the eight evaluable patients (62·50%). The median number of therapeutic vector copies per nucleated cell of patient BM and PB at the second year post-infusion was 0·18 (IQR 0·01-0·20) and 0·06 (0·01-0·19), respectively. No genotoxic events related to the gene therapy were observed. Most treatment-emergent adverse events (TEAEs) were non-serious and assessed as not related to therapeutic FANCA-encoding lentiviral vector. Nine serious adverse events (grade 3-4) were reported in six patients, one was considered related to medicinal product infusion, and all resolved without sequelae. Cytopenias and viral infections (common childhood illnesses) were the most frequently reported TEAEs.
    INTERPRETATION: These results show for the first time that haematopoietic gene therapy without genotoxic conditioning enables sustained engraftment and reversal of BMF progression in patients with Fanconi anaemia.
    FUNDING: European Commission, Instituto de Salud Carlos III, and Rocket Pharmaceuticals.
    DOI:  https://doi.org/10.1016/S0140-6736(24)01880-4
  36. Exp Hematol. 2024 Dec 06. pii: S0301-472X(24)00557-5. [Epub ahead of print] 104693
      Nucleic acid analogs, including cytarabine, decitabine, and azacitidine, have significantly advanced therapeutic approaches for myeloid tumors over the past five decades. Nucleic acid metabolism is a crucial pathway driving myeloid tumorigenesis, with emerging evidence indicating that myeloid tumors are particularly dependent on the de novo nucleotide synthesis pathway, underscoring its potential as a therapeutic target. This review provides a comprehensive overview of nucleic acid metabolism, with a particular focus on de novo nucleotide synthesis. We then describe the range of clinically utilized agents targeting nucleic acid metabolism and discuss our recent findings on the non-epigenetic actions of decitabine, as well as the therapeutic effects of IMPDH inhibitors in the treatment of myeloid tumors.
    Keywords:  Acute Myeloid Leukemia; Azacitidine; Decitabine; IMPDH; Myelodysplastic Syndromes; Nucleic Acid Metabolism; Purine; Pyrimidine
    DOI:  https://doi.org/10.1016/j.exphem.2024.104693
  37. Hematology Am Soc Hematol Educ Program. 2024 12 06. 2024(1): 335-339
      TP53-mutated myeloid disease is a constellation of abnormalities seen in both de novo and therapy-related acute myeloid leukemia and myelodysplastic syndrome. Historically, this group of disorders has had a poor prognosis. Newer treatment combinations allow patients to be treated with less toxicity. If response to induction therapy is achieved, fit and willing patients should be considered for allogeneic hematopoietic cell transplantation (HCT). The addition of allogeneic HCT to the treatment approach has modestly improved outcomes compared to chemotherapy alone, more so for those patients with disease control. Tailoring the conditioning regimen and maintenance therapy may improve outcomes in TP53 myeloid patients. In addition to chemotherapy, disease-modulating and immunological treatments continue to be studied to further improve outcomes.
    DOI:  https://doi.org/10.1182/hematology.2024000558
  38. Transl Oncol. 2024 Dec 06. pii: S1936-5233(24)00353-X. [Epub ahead of print]52 102227
      Ferroptosis is a novel type of programmed cell death caused by excessive iron-dependent lipid peroxidation. According to various studies, there may be a link between ferroptosis and lipid metabolism. However, few studies have been reported on the lipid metabolism of ferroptosis in acute myeloid leukemia (AML). Here, we analyzed the relationship between lipid metabolism and ferroptosis in AML cells to explore new clinical treatment strategies. This study found that 12 fatty acids were significantly changed in acute myeloid leukemia cell ferroptosis, including dihomo-γ-linolenic acid (DGLA), arachidonic acid (AA), docosahexaenoic acid (DHA), etc. Exogenous DGLA substantially increases the sensitivity to ferroptosis and induces ferroptosis alone in AML cells. In addition, acyl-CoA synthetase long-chain family member 4 (ACSL4) knockout significantly inhibited DGLA-induced AML cells ferroptosis, and ACSL4 regulates DGLA-associated lipid synthesis to affect the sensitivity of AML cells to ferroptosis. Collectively, our studies indicate that a DGLA-enriched diet significantly restricted the growth of leukemia cells as well as induced ferroptosis in vivo.
    Keywords:  ACSL4; Acute myeloid leukemia; Dihomo-γ-linolenic acid; Ferroptosis; Lipid metabolic
    DOI:  https://doi.org/10.1016/j.tranon.2024.102227
  39. Hematology Am Soc Hematol Educ Program. 2024 12 06. 2024(1): 287-292
      Classification of acute leukemia involves assigning lineage by resemblance of blasts to normal progenitor cells. This approach provides descriptive information that is useful for disease monitoring, provides clues to pathogenesis, and can help to select effective chemotherapeutic regimens. Acute leukemias of ambiguous lineage (ALAL) are those leukemias that either fail to show evidence of myeloid, B-lymphoid, or T-lymphoid lineage commitment or show evidence of commitment to more than 1 lineage, including mixed-phenotype acute leukemia (MPAL). The different treatment regimens for acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) make ALAL a challenge both diagnostically and therapeutically. Current classification criteria have reduced the reported incidence of mixed lineage leukemias by emphasizing fewer markers and categorizing some biphenotypic leukemias with recurrent cytogenetic abnormalities as other entities. Several recent studies have explored the genomic and epigenetic landscape of MPAL and emphasize the genomic heterogeneity of MPAL. Two classification proposals of myeloid malignancies recently been published and include International Consensus Classification and fifth edition of the World Health Organization Classification of Haematolymphoid Tumours. Our review aims to discuss the diagnostic challenges in the setting of classification updates, recent genomic studies, and therapeutic strategies in this poorly understood disease.
    DOI:  https://doi.org/10.1182/hematology.2024000554
  40. Hematology Am Soc Hematol Educ Program. 2024 12 06. 2024(1): 443-449
      Besides transfusion therapy, ineffective erythropoiesis contributes to systemic iron overload in myelodysplastic syndromes with ring sideroblasts (MDS-RS) via erythroferrone-induced suppression of hepcidin synthesis in the liver, leading to increased intestinal iron absorption. The underlying pathophysiology of MDS-RS, characterized by disturbed heme synthesis and mitochondrial iron accumulation, is less well understood. Several lines of evidence indicate that the mitochondrial transporter ABCB7 is critically involved. ABCB7 is misspliced and underexpressed in MDS-RS, due to somatic mutations in the splicing factor SF3B1. The pathogenetic significance of ABCB7 seems related to its role in stabilizing ferrochelatase, the enzyme incorporating iron into protoporphyrin IX to make heme. Although iron-related oxidative stress is toxic, many patients with MDS do not live long enough to develop clinical complications of iron overload. Furthermore, it is difficult to determine the extent to which iron overload contributes to morbidity and mortality in older patients with MDS, because iron-related complications overlap with age-related medical problems. Nevertheless, high-quality registry studies showed that transfusion dependency is associated with the presence of toxic iron species and inferior survival and confirmed a significant survival benefit of iron chelation therapy. The most widely used iron chelator in patients with MDS is deferasirox, owing to its effectiveness and convenient oral administration. Luspatercept, which can reduce SMAD2/SMAD3-dependent signaling implicated in suppression of erythropoiesis, may obviate the need for red blood cell transfusion in MDS-RS for more than a year, thereby diminishing further iron loading. However, luspatercept cannot be expected to substantially reduce the existing iron overload.
    DOI:  https://doi.org/10.1182/hematology.2024000569