bims-tremyl Biomed News
on Therapy resistance biology in myeloid leukemia
Issue of 2024‒11‒10
29 papers selected by
Paolo Gallipoli, Barts Cancer Institute, Queen Mary University of London



  1. Bone Marrow Transplant. 2024 Nov 06.
      Measurable residual disease (MRD) in adults with acute myeloid leukemia (AML) in complete remission is an important prognostic marker, but detection methodology requires optimization. Persistence of mutated NPM1 or FLT3-ITD in the blood of adult patients with AML in first complete remission (CR1) prior to allogeneic hematopoietic cell transplant (alloHCT) associates with increased relapse and death after transplant. The prognostic implications of persistence of other common AML-associated mutations, such as IDH1, at this treatment landmark however remain incompletely defined. We performed testing for residual IDH1 variants (IDH1m) in pre-transplant CR1 blood of 148 adult patients undergoing alloHCT for IDH1-mutated AML at a CIBMTR reporting site between 2013 and 2019. No statistically significant post-transplant differences were observed between those testing IDH1m positive (n = 53, 36%) and negative pre-transplant (overall survival (OS): p = 0.4; relapse: p = 0.5). For patients with IDH1 mutated AML co-mutated with NPM1 and/or FLT3-ITD, only detection of persistent mutated NPM1 and/or FLT3-ITD was associated with significantly higher rates of relapse (p = 0.01). These data, from the largest study to date, do not support the detection of IDH1 mutation in CR1 blood prior to alloHCT as evidence of AML MRD for increased post-transplant relapse risk.
    DOI:  https://doi.org/10.1038/s41409-024-02447-4
  2. Blood Adv. 2024 Nov 06. pii: bloodadvances.2024013304. [Epub ahead of print]
      In 2022, the European LeukemiaNet (ELN) risk stratification for patients with AML has been updated. We aimed to validate the prognostic value of the 2022 ELN classification (ELN22) evaluating 1,570 newly diagnosed AML patients (median age, 56 years) treated with cytarabine-based intensive chemotherapy regimens. As compared to the 2017 ELN classification (ELN17), allocating 595 (38%), 413 (26%) and 562 (36%) patients to the favorable, intermediate and adverse risk category, ELN22 risk was favorable, intermediate, and adverse in 575 (37%), 410 (26%), and 585 (37%) patients, respectively. Risk group allocation was revised in 340 patients (22%). Most patients were re-classified into ELN22 intermediate or ELN22 adverse risk group. The allocation of patients according to the ELN22 risk categories resulted in a significantly distinct event-free survival (EFS), relapse-free survival (RFS), and overall survival (OS). As compared to ELN17, reallocation according to the ELN22 recommendations resulted in a significantly improved prognostic discrimination for OS (3-year area under the curve (AUC) 0.71 vs. 0.67). In patients with ELN22 favorable risk AML, co-occurring MR gene mutations did not significantly impact outcome. Within the ELN22 adverse risk group, we observed marked survival differences across mutational groups (5-year OS rate of 21% and 3% in patients with myelodysplasia-related (MR) gene mutations and TP53-mutated patients, respectively). In patients harboring MR gene mutations, EZH2-, STAG2- and ZRSR2-mutated patients showed an intermediate-like OS. In patients with secondary AML and those who underwent allogeneic HCT, EFS and OS significantly differed between ELN22 risk groups, while prognostic abilities of ELN17 and ELN22 classifications were similar. In conclusion, the ELN22 risk stratification improves prognostic discrimination in a large cohort of intensively treated AML patients. Given the heterogeneous outcome in patients with MR gene alterations, ranging between those of intermediate and adverse risk patients, we suggest reevaluation of risk allocation in these patients.
    DOI:  https://doi.org/10.1182/bloodadvances.2024013304
  3. Leuk Lymphoma. 2024 Nov 04. 1-15
      Acute myeloid leukemia (AML) is a heterogeneous group of malignancies with poor prognosis. AML result from the proliferation of immature myeloid cells blocked at a variable stage of differentiation. Beyond inter-patient heterogeneity, AMLs are characterized by genetic and phenotypic intra-patient heterogeneity. Despite major advances in deciphering AML biology with bulk sequencing studies, pivotal questions remain unanswered. Analyses at the single-cell level could thus transform our understanding of these neoplasms. We review recent progresses in single-cell sequencing technologies from cell processing to bioinformatic pipelines. We next discuss how single-cell applications have helped understand the genetic and functional intra-leukemic heterogeneity, emphasizing aspects related to leukemic stem cells, clonal evolution and measurable residual disease (MRD) monitoring. We finally delineate how single-cell technologies could be implemented in routine clinical practice to improve patient management.
    Keywords:  Single-cell; acute myeloid leukemia; clonal architecture; clonal evolution; leukemic microenvironment; leukemic stem cells
    DOI:  https://doi.org/10.1080/10428194.2024.2422833
  4. Cancer Res. 2024 Nov 04.
      Internal tandem duplication (ITD) in the FMS-like receptor tyrosine kinase-3 (FLT3) is one of the most frequent mutations in acute myeloid leukemia (AML) and is associated with poor prognosis. FLT3-ITD mutations result in endoplasmic reticulum (ER) retention and constitutive autophosphorylation of FLT3. The PR/SET domain 16 (PRDM16) is highly expressed in FLT3-ITD+ AML patients, suggesting it might play a role in leukemogenesis. Here, we revealed that genetic and pharmacological suppression of PRDM16 greatly slowed the progression of FLT3-ITD-driven leukemia, sensitized leukemic cells to tyrosine kinase inhibitors (TKIs), and extended the survival of leukemic mice. PRDM16 enhanced activation of oncogenic FLT3-ITD and ligand-dependent activation of wild-type FLT3 in leukemic cells. Mechanistically, PRDM16 mediated monomethylation of FLT3-ITD at lysine 614 and promoted its ER localization, resulting in enhanced FLT3 signaling in leukemia cells. Moreover, pharmacological suppression of FLT3-ITD methylation in combination with TKIs increased the elimination of FLT3-ITD+ AML cells. Altogether, these results suggest that PRDM16 boosts oncogenic FLT3 signaling in leukemic cells by prompting FLT3-ITD methylation. Therefore, PRDM16 may serve as a therapeutic target for AML.
    DOI:  https://doi.org/10.1158/0008-5472.CAN-24-0577
  5. Leukemia. 2024 Nov 05.
      The use of measurable residual disease (MRD) as a biomarker for prognostication, risk stratification, and therapeutic decision-making in acute myeloid leukemia (AML) is gaining prominence. MRD monitoring for NPM1-mutated and core-binding factor AML using PCR techniques is well-established for assessing disease after intensive chemotherapy. AML with persistent FLT3-ITD MRD post-intensive chemotherapy and pre-allogeneic hematopoietic cell transplantation (pre-allo-HCT) is associated with an increased risk of relapse and lower survival. Pre-allo-HCT MRD is an independent risk factor for post-allo-HCT outcomes, including relapse and death. Therefore, preemptive interventions on the natural history of MRD positivity are an active area of research beyond its initial prognostic function. Targeting MRD in AML with innovative treatment strategies can improve patient outcomes.
    DOI:  https://doi.org/10.1038/s41375-024-02458-6
  6. Blood. 2024 Nov 06. pii: blood.2024026186. [Epub ahead of print]
      PURPOSE: Treatment outcomes for acute promyelocytic leukemia (APL) have improved with the widespread use of targeted therapy with all-trans retinoic acid (ATRA) and arsenic trioxide (ATO). Our study aimed to validate these data in a large patient cohort, and to redefine prognostic factors.PATIENTS AND METHODS: Leveraging the HARMONY Platform, we analyzed 1438 newly-diagnosed APL patients, diagnosed between 1999 to 2022. Patient data derived from the 2 international multicenter GIMEMA-APL0406 and NCRI-AML17 trials, and 4 European registries (HOVON, AMLSG, Swedish AML Registry and SAL).
    RESULTS: The study cohort included 721 males and 717 females, with a median age of 50.5 years (range 16-94 years). Of 1309 patients starting therapy, 562 received ATRA-ATO, and 747 AIDA-like chemotherapy. Early death (ED) occurred in 85 of 1438 patients (5.9%) at a median of 9 days after APL diagnosis and was independently associated with increasing age and high Sanz risk score (OR:1.06, 95% C.I: 1.04-1.08, and OR:4.65, 95% C.I.:2.55-8.51, respectively).The median follow-up was 5.5 years (IQR=3.2-7.5). ATRA-ATO regimen was associated with the best outcome, reaching 91% 7-year overall survival (vs 81% for AIDA-like, HR:2.14, 95%C.I.:1.51-3.05), 89% event-free survival (vs 71% for AIDA-like, HR:2.72 95%CI: 2.01-3.69) and 3% relapse (vs 13% for AIDA-like, HR:4.19, 95%CI:2.38-7.39, p<0.001 for all outcomes). The survival advantage of ATRA/ATO was independent of patients' age, Sanz-risk score, and treatment scenario.
    CONCLUSIONS: Our study confirms the superiority of ATRA-ATO over ATRA-chemotherapy in APL patients. ED represents an unmet medical need, in particular in older patients and in high-risk APL.
    DOI:  https://doi.org/10.1182/blood.2024026186
  7. Blood. 2024 Nov 01. pii: blood.2024026925. [Epub ahead of print]
      The ELN 2024 risk-stratification guidelines for patients with acute myeloid leukemia receiving hypomethylating agents combined with venetoclax were recently published. This analysis demonstrates re-classification and incorporation of new gene mutations in the present model can further improve and individualize prognostication.
    DOI:  https://doi.org/10.1182/blood.2024026925
  8. Haematologica. 2024 Nov 07.
      Since 2017, targeted therapies combined with conventional intensive chemotherapy have started to improve outcome of patients with acute myeloid leukemia (AML). However, even before these innovations outcomes with intensive chemotherapy have improved, which has not yet been extensively studied. Thus, we used a large pan-European multicenter dataset of the HARMONY Alliance to evaluate treatment-time dependent outcomes over two decades. In 5359 AML patients, we compared the impact of intensive induction therapy on outcome over four consecutive 5-year calendar periods from 1997 to 2016. During that time, the 5- year survival of AML patients improved significantly, also across different genetic risk groups. In particular, the 60-day mortality rate has dropped from 13.0% to 4.7% over time. The independent effect of calendar periods on outcome was confirmed in multivariate models. Improvements were documented both for patients.
    DOI:  https://doi.org/10.3324/haematol.2024.285805
  9. Elife. 2024 Nov 06. pii: RP92074. [Epub ahead of print]12
      The advent of tyrosine kinase inhibitors (TKIs) as treatment of chronic myeloid leukemia (CML) is a paradigm in molecularly targeted cancer therapy. Nonetheless, TKI-insensitive leukemia stem cells (LSCs) persist in most patients even after years of treatment and are imperative for disease progression as well as recurrence during treatment-free remission (TFR). Here, we have generated high-resolution single-cell multiomics maps from CML patients at diagnosis, retrospectively stratified by BCR::ABL1IS (%) following 12 months of TKI therapy. Simultaneous measurement of global gene expression profiles together with >40 surface markers from the same cells revealed that each patient harbored a unique composition of stem and progenitor cells at diagnosis. The patients with treatment failure after 12 months of therapy had a markedly higher abundance of molecularly defined primitive cells at diagnosis compared to the optimal responders. The multiomic feature landscape enabled visualization of the primitive fraction as a mixture of molecularly distinct BCR::ABL1+ LSCs and BCR::ABL1-hematopoietic stem cells (HSCs) in variable ratio across patients, and guided their prospective isolation by a combination of CD26 and CD35 cell surface markers. We for the first time show that BCR::ABL1+ LSCs and BCR::ABL1- HSCs can be distinctly separated as CD26+CD35- and CD26-CD35+, respectively. In addition, we found the ratio of LSC/HSC to be higher in patients with prospective treatment failure compared to optimal responders, at diagnosis as well as following 3 months of TKI therapy. Collectively, this data builds a framework for understanding therapy response and adapting treatment by devising strategies to extinguish or suppress TKI-insensitive LSCs.
    Keywords:  BCR-ABL1; CD26; CD35; CITE-Seq; CML; cancer biology; genetics; genomics; human; leukemic stem cell
    DOI:  https://doi.org/10.7554/eLife.92074
  10. JCI Insight. 2024 Nov 05. pii: e183889. [Epub ahead of print]
      MYB fusions are recurrently found in select cancers, including blastic plasmacytoid dendritic cell neoplasm (BPDCN), an acute leukemia with poor prognosis. They are markedly enriched in BPDCN compared to other blood cancers, and in some patients are the only obvious somatic mutation detected. This suggests they may alone be sufficient to drive dendritic cell transformation. MYB fusions are hypothesized to alter the normal transcription factor activity of MYB, but mechanistically how they promote leukemogenesis is poorly understood. Using CUT&RUN chromatin profiling, we found that in BPDCN leukemogenesis, MYB switches from being a regulator of dendritic cell lineage genes to aberrantly regulating G2/M cell cycle control genes. MYB fusions found in BPDCN patients increased the magnitude of DNA binding at these locations, and this was linked to BPDCN-associated gene expression changes. Furthermore, expression of MYB fusions in vivo impaired dendritic cell differentiation and induced transformation to generate a mouse model of myeloid-dendritic acute leukemia. Therapeutically, we present evidence that all-trans retinoic acid (ATRA) may cause loss of MYB protein and cell death in BPDCN.
    Keywords:  Hematology; Leukemias; Oncogenes
    DOI:  https://doi.org/10.1172/jci.insight.183889
  11. Nat Cell Biol. 2024 Nov 06.
      RNA modification has emerged as an important epigenetic mechanism that controls abnormal metabolism and growth in acute myeloid leukaemia (AML). However, the roles of RNA N4-acetylcytidine (ac4C) modification in AML remain elusive. Here, we report that ac4C and its catalytic enzyme NAT10 drive leukaemogenesis and sustain self-renewal of leukaemic stem cells/leukaemia-initiating cells through reprogramming serine metabolism. Mechanistically, NAT10 facilitates exogenous serine uptake and de novo biosynthesis through ac4C-mediated translation enhancement of the serine transporter SLC1A4 and the transcription regulators HOXA9 and MENIN that activate transcription of serine synthesis pathway genes. We further characterize fludarabine as an inhibitor of NAT10 and demonstrate that pharmacological inhibition of NAT10 targets serine metabolic vulnerability, triggering substantial anti-leukaemia effects both in vitro and in vivo. Collectively, our study demonstrates the functional importance of ac4C and NAT10 in metabolism control and leukaemogenesis, providing insights into the potential of targeting NAT10 for AML therapy.
    DOI:  https://doi.org/10.1038/s41556-024-01548-y
  12. Leuk Lymphoma. 2024 Nov 06. 1-10
      SETBP1 mutations (m) have been previously reported in myeloid neoplasms and are associated with poor prognostic co-mutations and cytogenetic abnormalities. We retrospectively analyzed the charts of 113 patients diagnosed with myeloid neoplasms with SETBP1m. The most common diagnosis was MDS (31%). Cytogenetics were abnormal in 51 cases (46.4%), with monosomy 7 being the most common (41.1%). The most frequent co-mutations were ASXL1 (71.7%), SRSF2 (46.9%), TET2 (20.4%). Higher SETBP1m VAF was associated with proliferative features (p < 0.05). Most SETBP1m (96.5%) were in one of three hotspots (Asp868, Gly870, Ile871), with Asp868m being most frequent (51.3%). Patients with Ile871m had higher number of co-mutations (median= 4) compared to Asp868m and Gly870m (p = 0.07). On multivariate analysis, age ≥ 70 years (p = 0.004) and higher peripheral blood blasts (p = 0.02) had worse OS. Patients with Ile871m had lower OS when compared with Asp868m and Gly870m (5.5 months vs. 17.4 and 17 months, respectively, p = 0.1).
    Keywords:  Myeloid neoplasms; SETBP1; leukemia associated genes
    DOI:  https://doi.org/10.1080/10428194.2024.2425048
  13. Br J Haematol. 2024 Nov 06.
      The TOPASE study was set up to evaluate the outcomes of chronic myeloid leukaemia [CML] patients treated with ponatinib (PON) in a real-world setting in France. One hundred and twenty CML patients, 105 in chronic phase (CP), 8 in accelerated phase (AP) and 7 in blastic phase (BP) were included. Fifty-one (49%) of the CP-CML patients were in third line of treatment. The trigger for PON initiation in CP-CML was 'poor response' in 67 patients, 'poor tolerance' in 28 patients and 'response enhancement' in seven patients. The median dose at initiation was 30 mg/day [Q1; Q3 = 15; 30] in CP-CML and 45 mg/day [Q1; Q3 = 30; 45] in AP/BP-CML. Of 98 CP-CML evaluable patients, 72 (73.5%) were considered as responders (MMR) at one time point at least once, especially for those in second line of treatment and/or presenting a T315I mutation. Ninety-six of 120 (80%) patients reported at least one adverse event. An arterial occlusive event (AOE) was reported in 11 patients (9.2%). Thus, these real-life data confirm the potency of ponatinib in resistant or intolerant patients with an acceptable safety profile in non-selected patients. NCT number: NCT04048564.
    Keywords:  CML; TKI; ponatinib; real‐life setting
    DOI:  https://doi.org/10.1111/bjh.19819
  14. Trends Mol Med. 2024 Oct 25. pii: S1471-4914(24)00272-7. [Epub ahead of print]
      Clonal hematopoiesis (CH) of indeterminate potential (CHIP), characterized by propagation of blood cell clones carrying somatic mutations in specific driver genes, is increasingly recognized as a critical factor in the development of hematological malignancies. This phenomenon, which often emerges with age, underscores the complex interplay between genetic predisposition and environmental influences in cancer initiation and progression. Recent years have witnessed significant advances in our understanding of the link between CHIP and hematological diseases. In this review, we provide a comprehensive overview of the features of CHIP and explore its role in promoting tumorigenesis and influencing treatment outcomes for blood cancers. Finally, we summarize current available tools for risk stratification and discuss management strategies for patients with CHIP.
    Keywords:  cellular therapies; clonal evolution; clonal hematopoiesis of indeterminate potential; hematological malignancies
    DOI:  https://doi.org/10.1016/j.molmed.2024.10.005
  15. Br J Haematol. 2024 Nov 05.
      Venous thromboembolism (VTE) is the third most common cardiovascular disease. Clonal haematopoiesis (CH) is linked to cardiovascular disease risk, but its potential association with VTE remains poorly understood. We assessed the prevalence of CH in patients with recurrent VTE (n = 107; median age [IQR] 57 [48-63] years, 44.9% female) and matched healthy controls (n = 127; median age [IQR] 53 [45-60] years, 51.2% female) to investigate a putative association of CH with VTE risk. We detected 12 CH-associated mutations in 11 (10.3%) VTE cases and six mutations in 5 (3.9%) controls. Thus, patients with recurrent VTE tended to have higher odds of presenting with CH compared to controls (OR: 2.74, 95% CI: 0.95-9.16). Moreover, the odds of detecting CH were significantly higher in VTE cases in the subgroup of individuals without thrombophilia (OR: 4.58, 95% CI: 1.48-15.99). VTE cases with CH showed elevated platelet counts compared to cases and controls without CH (median [IQR]: 292 [254-298], 223 [198-260] and 220 [185-259] × 109/L; both p < 0.01). Fibrinogen, sP-selectin, D-dimer and hsCRP levels did not differ according to CH status. Overall, we identified a trend for an association between CH and recurrent VTE, particularly in individuals without underlying thrombophilia, warranting further research in this patient group.
    Keywords:  clonal haematopoiesis; risk factors; thromboembolism; thrombophilia; venous thromboembolism
    DOI:  https://doi.org/10.1111/bjh.19871
  16. Oncogene. 2024 Nov 01.
      Sex influences many biological outcomes, but how sex affects hematopoietic stem cell (HSC) aging and hematological disorders is poorly understood. The widespread use of young animal models to study age-related diseases further complicates these matters. Using aged and long-lived BALB/c mouse models, we discovered that aging mice exhibit sex-dependent disparities, mirroring aging humans, in developing myeloid skewing, anemia, and leukemia. These disparities are underlined by sex-differentiated HSC aging characteristics across the population, single-cell, and molecular levels. The HSC population expanded significantly with aging and longevity in males, but this occurred to a much lesser degree in aging females that instead expanded committed progenitors. Aging male HSCs are more susceptible to BCR-ABL1 transformation with faster development of chronic myeloid leukemia (CML) than female HSCs. Additionally, the loss of the aging regulator Sirt1 inhibited CML development in aging male but not female mice. Our results showed for the first time that sex-differentiated HSC aging impacts hematopoiesis, leukemogenesis, and certain gene functions. This discovery provides insights into understanding age-dependent hematological diseases and sex-targeted strategies for the treatment and prevention of certain blood disorders and cancer.
    DOI:  https://doi.org/10.1038/s41388-024-03197-9
  17. Leukemia. 2024 Nov 06.
      It is estimated that 10% of individuals with a myeloid malignancy carry a germline susceptibility. Using the genome-first approach, in which individuals were ascertained on genotype alone, rather than clinical phenotype, we quantified the prevalence and penetrance of pathogenic germline variants in eight myeloid malignancy predisposition (gMMP) genes. ANKRD26, CEBPA, DDX41, MECOM, SRP72, ETV6, RUNX1 and GATA2, were analyzed from the Geisinger MyCode DiscovEHR (n = 170,503) and the United Kingdom Biobank (UKBB, n = 469,595). We identified a high risk of myeloid malignancies (MM) (odds ratio[OR] all genes: DiscovEHR, 4.6 [95% confidential interval (CI) 2.1-9.7], p < 0.0001; UKBB, 6.0 [95% CI 4.3-8.2], p = 3.1 × 10-27), and decreased overall survival (hazard ratio [HR] DiscovEHR, 1.8 [95% CI 1.3-2.6], p = 0.00049; UKBB, 1.4 [95% CI 1.2-1.8], p = 8.4 × 10-5) amongst heterozygotes. Pathogenic DDX41 variants were the most commonly identified, and in UKBB showed a significantly increased risk of MM (OR 5.7 [95% CI 3.9-8.3], p = 6.0 × 10-20) and increased all-cause mortality (HR 1.35 [95% CI 1.1-1.7], p = 0.0063). Through a genome-first approach, this study genetically ascertained individuals with a gMMP and determined their MM risk and survival.
    DOI:  https://doi.org/10.1038/s41375-024-02436-y
  18. Exp Hematol. 2024 Nov 02. pii: S0301-472X(24)00534-4. [Epub ahead of print] 104669
      Induced pluripotent stem cells (iPSCs) have emerged as powerful tools for in vitro modeling of bone marrow failure (BMF) syndromes and hereditary conditions predisposing to myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). This review synthesizes recent advances in iPSC-based disease modeling for various inherited BMF/MDS disorders, including Fanconi anemia, dyskeratosis congenita, Diamond Blackfan anemia syndrome, Shwachman-Diamond syndrome, severe congenital neutropenia, and GATA2, RUNX1, ETV6, ANKRD26, SAMD9, SAMD9L and ADH5/ALDH2 syndromes. While the majority of these iPSC lines are derived from patient cells, some are generated by introducing patient-specific mutations into healthy iPSC backgrounds, offering complementary approaches to disease modeling. The review highlights the ability of iPSCs to recapitulate key disease phenotypes, such as impaired hematopoietic differentiation, telomere dysfunction, and defects in DNA repair or ribosome biogenesis. We discuss how these models have enhanced our understanding of disease pathomechanisms, hematopoietic defects, and potential therapeutic approaches. Challenges in generating and maintaining disease-specific iPSCs are examined, particularly for disorders involving DNA repair. We emphasize the necessity of creating isogenic controls to elucidate genotype-phenotype relationships. Furthermore, we address limitations of current iPSC models, including genetic variability among iPSC clones derived from the same patient, and difficulties in achieving robust engraftment of iPSC-derived hematopoietic progenitor cells in mouse transplantation models. The review also explores future directions, including the potential of iPSC models for drug discovery and personalized medicine approaches. This review underscores the significance of iPSC technology in advancing our understanding of inherited hematopoietic disorders and its potential to inform novel therapeutic strategies.
    DOI:  https://doi.org/10.1016/j.exphem.2024.104669
  19. Expert Rev Hematol. 2024 Nov 04. 1-12
      INTRODUCTION: The disruption of the JAK/STAT signaling pathway is a defining feature of myelofibrosis (MF). The introduction of JAK inhibitors (JAKi) has transformed the therapeutic approach to MF, becoming essential to treatment and reshaping the management landscape. While JAKi are now the preferred first-line treatment for most patients, various management options are available for those who do not respond to initial therapy.AREAS COVERED: This review focuses on management options for patients with MF, with particular emphasis on therapeutic strategies following the failure of first-line JAKi. It provides a comprehensive overview of the current treatment landscape, including alternative JAKi and other approaches. The review is based on an extensive literature search using available databases (PubMed, Cochrane …) and relevant web resources (clinicaltrials.gov).
    EXPERT OPINION: Ruxolitinib benefits in MF often diminish after 3-4 years, with complications like thrombocytopenia and anemia. Three newer JAKi offer alternatives with similar efficacy and varied side effects. Stem cell transplantation is a curative option for a minority, ideally timed at peak response to JAKi. Research aims to enhance first-line treatments and restore responses in resistant patients. Future therapies may include novel combinations or immunotherapies targeting specific mutations, requiring collaboration between patient, clinical, and pharmaceutical communities.
    Keywords:  JAK inhibitors; disease modification; myelofibrosis; myeloproliferative neoplasms; ruxolitinib; treatment landscape
    DOI:  https://doi.org/10.1080/17474086.2024.2423367
  20. Bioessays. 2024 Nov 06. e2400154
      Hematopoiesis unfolds within the bone marrow niche where hematopoietic stem cells (HSCs) play a central role in continually replenishing blood cells. The hypoxic bone marrow environment imparts peculiar metabolic characteristics to hematopoietic processes. Here, we discuss the internal metabolism of HSCs and describe external influences exerted on HSC metabolism by the bone marrow niche environment. Importantly, we suggest that the metabolic environment and metabolic cues are intertwined with HSC cell fate, and are crucial for hematopoietic processes. Metabolic dysregulation within the bone marrow niche during acute stress, inflammation, and chronic inflammatory conditions can lead to reduced HSC vitality. Additionally, we raise questions regarding metabolic stresses imposed on HSCs during implementation of stem cell protocols such as allo-SCT and gene therapy, and the potential ramifications. Enhancing our comprehension of metabolic influences on HSCs will expand our understanding of pathophysiology in the bone marrow and improve the application of stem cell therapies.
    Keywords:  hematopoiesis; metabolism; stem cells
    DOI:  https://doi.org/10.1002/bies.202400154
  21. Eur J Haematol. 2024 Nov 05.
      OBJECTIVES: Allogeneic hematopoietic stem cell transplantation (HSCT) effectively treats high-risk myeloid neoplasms, but relapses post-HSCT, particularly in acute myeloid leukemia (AML) and myelodysplastic neoplasms (MDS), pose significant challenges. Donor lymphocyte infusion (DLI) has been utilized, but its effectiveness, especially in haploidentical settings, remains insufficiently clarified, and graft-versus-host disease (GvHD) poses a substantial risk.METHODS: In this retrospective cohort study, 57 patients with AML or MDS who received DLI after allogeneic HSCT at our center from 2002 to 2023 were analyzed. Herein, only preemptively or therapeutically applied DLI were included, and endpoints included overall survival (OS), progression-free survival (PFS), and GvHD incidence post-DLI.
    RESULTS: Median OS after DLI was 517 days, with a 1-year OS of 62.5%. Factors associated with longer OS included patient age, HLA-identical donor, post-HSCT treatment naivety, and preemptive DLI indication. Haploidentical DLI was associated with inferior OS compared to HLA-identical DLI; however, PFS and GvHD incidence post-DLI did not differ significantly.
    CONCLUSIONS: Our study findings indicate that OS rate is inferior in patients with relapsed AML or MDS treated with haploidentical DLI in comparison to those who received HLA-identical DLI. Given the limitations of haploidentical DLI, alternative strategies, such as higher cell doses or combination treatment approaches, warrant further investigation.
    Keywords:  acute myeloid leukemia; allogeneic hematopoietic stem cell transplantation; donor lymphocyte infusion; haploidentical hematopoietic stem cell transplantation; myelodysplastic neoplasms
    DOI:  https://doi.org/10.1111/ejh.14340
  22. Cardiooncology. 2024 Nov 01. 10(1): 75
      Venetoclax is a promising drug for patients with acute myeloid leukemia (AML) ineligible for anthracycline-based treatments. In rats, venetoclax is reported to cause myocardial injury. Our objectives were to report the frequency of cardiovascular (CV) events in patients treated with venetoclax, and, subsequently, to compare CV outcomes in matched patients treated with venetoclax or anthracyclines. Patients diagnosed with AML and treated with venetoclax or anthracyclines from January 2017 to July 2021 were identified. Major adverse cardiac events (MACE, including new-onset heart failure (HF), acute myocardial infarction, new onset atrial fibrillation (AF)) were recorded. Propensity-score method was then used to compare patients treated with venetoclax or anthracyclines. Patients treated with venetoclax (n=103) were older, with more hyperlipidemia than patients treated with anthracyclines (n=217). However, only 63% of patients treated with venetoclax underwent echocardiographic screening (vs. 93% of patients treated with anthracyclines, P< 0.001). Eighteen patients with venetoclax (17%) and 27 patients with anthracyclines (12%) developed MACE, including 10 % of new HF in each group. The median time to MACE was 8 days (interquartile range 5-98 days). In the matched cohort (n=132 patients), the cumulative incidence of MACE at one year was not different (17.5 % venetoclax, 9.2% anthracyclines, p =0.27). Thus, MACE incidence is similar in matched patients receiving venetoclax or anthracyclines. Close CV monitoring during the early phase of treatment may be helpful in patients treated with venetoclax.
    Keywords:  Atrial fibrillation; Cardiotoxicity; Heart failure; Venetoclax
    DOI:  https://doi.org/10.1186/s40959-024-00275-5
  23. Cell Stem Cell. 2024 Nov 01. pii: S1934-5909(24)00366-7. [Epub ahead of print]
      Elucidating mechanisms of T cell development can guide in vitro T cell differentiation from induced pluripotent stem cells (iPSCs) and facilitate off-the-shelf T cell-based immunotherapies. Using a stroma-free human iPSC-T cell differentiation platform, we screened for epigenetic modulators that influence T cell specification and identified the H3K9-directed histone methyltransferases G9a/GLP as repressors of T cell fate. We show that G9a/GLP inhibition during specific time windows of differentiation of hematopoietic stem and progenitor cells (HSPCs) skews cell fates toward lymphoid lineages. Inhibition of G9a/GLP promotes the production of lymphoid cells during zebrafish embryonic hematopoiesis, demonstrating the evolutionary conservation of G9a/GLP function. Importantly, chemical inhibition of G9a/GLP facilitates the generation of mature iPSC-T cells that bear transcriptional similarity to peripheral blood αβ T cells. When engineered to express chimeric antigen receptors, the epigenetically engineered iPSC-T cells exhibit enhanced effector functions in vitro and durable, persistent antitumor activity in a xenograft tumor-rechallenge model.
    Keywords:  CAR-T cells; G9a/GLP; T cell differentiation; cancer immunotherapy; chemical screen; epigenetic regulation; hematopoiesis; lymphoid development; pluripotent stem cells
    DOI:  https://doi.org/10.1016/j.stem.2024.10.004
  24. Blood Cancer J. 2024 11 06. 14(1): 195
      We analyzed the neutrophil-to-lymphocyte ratio (NLR) in 1508 patients with PV and found that those with an NLR ≥ 5 were generally older, had a longer disease history, and had higher cardiovascular risk factors, more arterial thrombosis, and more aggressive blood counts, indicating a more proliferative disease. NLR was an accurate predictor of mortality, with patients with NLR ≥ 5 having significantly worse overall survival and more than twice the mortality rate compared to those with NLR < 5. Multivariable models confirmed that increasing age, previous venous thrombosis and NLR ≥ 5 were strong predictors of death, further influenced by cardiovascular risk factors. We examined the interaction between NLR and the number of cardiovascular risk factors and found a progressive trend of increased mortality risk for NLR values ≥ 5 in addition to the presence of more than one risk factor. In conclusion, patients with NLR ≥ 5 require careful monitoring and management of cardiovascular risk factors because they increase mortality when associated with progressive levels of NLR.
    DOI:  https://doi.org/10.1038/s41408-024-01176-7
  25. Nature. 2024 Nov 06.
      Mitochondria serve a crucial role in cell growth and proliferation by supporting both ATP synthesis and the production of macromolecular precursors. Whereas oxidative phosphorylation (OXPHOS) depends mainly on the oxidation of intermediates from the tricarboxylic acid cycle, the mitochondrial production of proline and ornithine relies on reductive synthesis1. How these competing metabolic pathways take place in the same organelle is not clear. Here we show that when cellular dependence on OXPHOS increases, pyrroline-5-carboxylate synthase (P5CS)-the rate-limiting enzyme in the reductive synthesis of proline and ornithine-becomes sequestered in a subset of mitochondria that lack cristae and ATP synthase. This sequestration is driven by both the intrinsic ability of P5CS to form filaments and the mitochondrial fusion and fission cycle. Disruption of mitochondrial dynamics, by impeding mitofusin-mediated fusion or dynamin-like-protein-1-mediated fission, impairs the separation of P5CS-containing mitochondria from mitochondria that are enriched in cristae and ATP synthase. Failure to segregate these metabolic pathways through mitochondrial fusion and fission results in cells either sacrificing the capacity for OXPHOS while sustaining the reductive synthesis of proline, or foregoing proline synthesis while preserving adaptive OXPHOS. These findings provide evidence of the key role of mitochondrial fission and fusion in maintaining both oxidative and reductive biosyntheses in response to changing nutrient availability and bioenergetic demand.
    DOI:  https://doi.org/10.1038/s41586-024-08146-w
  26. Nature. 2024 Nov 06.
      Somatic alterations in the oncogenic kinase AKT1 have been identified in a broad spectrum of solid tumours. The most common AKT1 alteration replaces Glu17 with Lys (E17K) in the regulatory pleckstrin homology domain1, resulting in constitutive membrane localization and activation of oncogenic signalling. In clinical studies, pan-AKT inhibitors have been found to cause dose-limiting hyperglycaemia2-6, which has motivated the search for mutant-selective inhibitors. We exploited the E17K mutation to design allosteric, lysine-targeted salicylaldehyde inhibitors with selectivity for AKT1 (E17K) over wild-type AKT paralogues, a major challenge given the presence of three conserved lysines near the allosteric site. Crystallographic analysis of the covalent inhibitor complex unexpectedly revealed an adventitious tetrahedral zinc ion that coordinates two proximal cysteines in the kinase activation loop while simultaneously engaging the E17K-imine conjugate. The salicylaldimine complex with AKT1 (E17K), but not that with wild-type AKT1, recruits endogenous Zn2+ in cells, resulting in sustained inhibition. A salicylaldehyde-based inhibitor was efficacious in AKT1 (E17K) tumour xenograft models at doses that did not induce hyperglycaemia. Our study demonstrates the potential to achieve exquisite residence-time-based selectivity for AKT1 (E17K) by targeting the mutant lysine together with Zn2+ chelation by the resulting salicylaldimine adduct.
    DOI:  https://doi.org/10.1038/s41586-024-08176-4
  27. Bone Marrow Transplant. 2024 Nov 06.
      REACH2 and REACH3 were randomized, multicenter, open-label phase 3 studies comparing the selective Janus kinase (JAK)1/JAK2 inhibitor ruxolitinib versus investigators' choice of best available therapy (BAT) in steroid-refractory (SR) acute (REACH2) or chronic (REACH3) graft-versus-host disease (aGVHD/cGVHD). Moderate-severe aGVHD/cGVHD can progress rapidly; thus, key clinical considerations driving management of patients with SR-aGVHD/SR-cGVHD are prompt treatment initiation and concomitant cytopenias. These post hoc analyses of REACH2/REACH3 describe the impact of timing of treatment initiation after SR-aGVHD/SR-cGVHD diagnosis and development of concomitant cytopenias on treatment outcomes. Ruxolitinib initiation within 3 days from SR-aGVHD diagnosis yielded an extended duration of response and higher Day 28 complete response rates compared with initiation ≥7 days after SR-aGVHD diagnosis (median 178 vs 167 days and 36.6% vs 25.0%, respectively). For patients with SR-cGVHD, Week 24 overall response was not impacted by time to treatment (54.5% vs 42.6% for <14 vs >28 days). Clinically relevant cytopenias were manageable, allowing for maintenance of dose intensity (median 20 mg/d), and did not impact the favorable efficacy outcomes from ruxolitinib treatment. This analysis highlights the practical importance of considering earlier ruxolitinib initiation after SR diagnosis in GVHD and the benefits of ruxolitinib treatment compared with BAT even for patients with cytopenias.
    DOI:  https://doi.org/10.1038/s41409-024-02445-6