bims-tremyl Biomed News
on Therapy resistance biology in myeloid leukemia
Issue of 2026–04–19
29 papers selected by
Paolo Gallipoli, Barts Cancer Institute, Queen Mary University of London



  1. Leukemia. 2026 Apr 17.
      Interleukin-23 receptor (IL-23R) is a cell surface cytokine receptor classically expressed on T cells, where it regulates T cell activation. Here, we discovered a novel intracellular localization and function for IL-23R in Acute Myeloid Leukemia (AML). Compared to normal hematopoietic cells, IL-23R was increased in primary AML samples. IL-23R was predominantly localized intracellularly in AML cells. BioID mass spectrometry identified mitotic spindle proteins as top interactors with IL-23R. We confirmed interaction between endogenous IL-23R and the mitotic spindle in AML cells and primary AML samples, and this interaction was mediated by IL-23R's (S/T)x(I/L)P motif. Genetic depletion of IL-23R disrupted mitotic spindle formation and reduced proliferation and stem cell/progenitor function of AML cell lines and primary AML samples. In contrast, depletion of IL-23R spared normal hematopoietic cells and progenitors. Thus, we discovered a novel intracellular function for IL-23R where this receptor regulates mitotic spindle formation and the growth of AML cells.
    DOI:  https://doi.org/10.1038/s41375-026-02949-8
  2. Leukemia. 2026 Apr 15.
      MDM2 is an E3 ubiquitin ligase that promotes p53 tumor suppressor degradation and has emerged as a therapeutic target in the treatment of wild-type (wt) TP53 tumors. In acute myeloid leukemia (AML), TP53 mutations are infrequent (15-20%), but wt-p53 is often inactivated through overexpression of MDM2. Thus, MDM2 inhibitors are currently in clinical trials for AML. However, p53 stabilization with inhibitors upregulates MDM2, which limits their clinical efficacy. Proteolysis-targeting chimeric (PROTAC) molecules that degrade MDM2 may overcome this feedback. MD-265 is a PROTAC that recruits CRBN, degrades MDM2, restores p53 and induces apoptosis. We tested MD-265 in ex vivo cultures of 105 primary leukemic stem cells (LSCs). The median cytotoxic IC50 for MD-265 was 16 nM, median IC50 for MI-1061 was 150-fold higher. LSCs with IC50 > 1 µM were classified as MD-265 resistant and harbored mutations in TP53. Normal hematopoietic stem cells showed 100-fold higher IC50 (818 nM) than LSCs. AML patient-derived xenograft (PDX) models in NSG-SGM3 mice were treated with MD-265 or an oral MDM2 inhibitor. In PDX models, MD-265 was not toxic and prolonged survival. MD-265 is a potent and specific MDM2 degrader with broad pre-clinical activity and a promising drug candidate for the treatment of leukemias.
    DOI:  https://doi.org/10.1038/s41375-026-02957-8
  3. Blood. 2026 Apr 14. pii: blood.2025032033. [Epub ahead of print]
      Relapse after remission remains the primary cause of treatment failure in acute myeloid leukemia (AML), underscoring the need for strategies to eliminate residual leukemic cells. The bone marrow microenvironment, largely orchestrated by the CXCR4-CXCL12 axis, enables leukemia cell survival and chemoresistance by anchoring blasts in their protective bone marrow niche. Motixafortide, a selective CXCR4 antagonist, mobilizes leukemic cells and disrupts tumor-microenvironment interactions in preclinical models. In this randomized, double-blind, placebo-controlled phase II trial (NCT02502968; registered at ClinicalTrials.gov), 128 patients in first remission received high‑dose cytarabine (HiDAC) plus Motixafortide or placebo. Median relapse-free survival (RFS) did not substantially differ between groups: 10.3 months (95% CI, 8.0-12.0) for Motixafortide and 11.5 months (95% CI, 8.6-24.1) for placebo (log-rank p=0.98). But scMRD analysis, performed before consolidation, demonstrated heterogeneity of CXCR4 inhibition benefit: in the placebo group, higher CXCR4 expression was associated with increased relapse risk (p=0.02), whereas in the Motixafortide group, higher CXCR4 expression was linked to a reduced relapse rate (p=0.047). Exploratory analyses identified scMRD levels at which higher MRD burden was associated with inferior overall survival (OS). Taken together, combining functional MRD profiling with biomarker-driven patient selection, such as CXCR4 expression, may enable more precise and effective post-remission interventions in AML. This clinical trial is registered at EudraCT number: 2014-002702-21.
    DOI:  https://doi.org/10.1182/blood.2025032033
  4. Blood Neoplasia. 2026 May;3(2): 100196
      Resistance to combination regimens containing the B-cell lymphoma 2 (BCL-2) inhibitor and BH3 mimetic venetoclax in acute myeloid leukemia (AML) is a growing clinical challenge for this extensively used agent. We previously established the antileukemic properties of ceramide, a tumor-suppressive sphingolipid, in AML, and demonstrated that upregulated expression of acid ceramidase (AC), a ceramide-neutralizing enzyme, supports leukemic survival and resistance to BH3 mimetics. Here, we report the antileukemic efficacy and mechanisms of cotargeting AC and BCL-2 in venetoclax-resistant AML. Analysis of the BeatAML data set revealed a positive relationship between increased AC gene expression and venetoclax resistance. Pharmacologic AC inhibition with the ceramide analog SACLAC enhanced single-agent venetoclax cytotoxicity and the venetoclax + cytarabine combination in AML cell lines with primary or acquired venetoclax resistance. SACLAC + venetoclax was synergistically lethal when evaluated ex vivo across a cohort of venetoclax-resistant (n = 21) and venetoclax-sensitive (n = 46) primary samples from patients with AML. Moreover, the SACLAC + venetoclax combination was equipotent to the combination of venetoclax + cytarabine at reducing cell viability across primary patient samples. Mechanistically, cotargeting AC and BCL-2 increased ceramide to levels that trigger a cytotoxic integrated stress response (ISR), ISR-mediated NOXA protein upregulation, mitochondrial dysregulation, and caspase-dependent cell death. Importantly, AC knockdown sensitized AML cells to venetoclax and induced NOXA protein accumulation, whereas NOXA knockdown protected against AC and BCL-2 cotargeting. Collectively, these findings demonstrate the efficacy of cotargeting AC and BCL-2, and rationalize targeting AC as a therapeutic approach for venetoclax-sensitive and -resistant AML.
    DOI:  https://doi.org/10.1016/j.bneo.2026.100196
  5. Clin Lymphoma Myeloma Leuk. 2026 Mar 20. pii: S2152-2650(26)00076-5. [Epub ahead of print]
      The 2022 European LeukaemiaNet acute myeloid leukemia (AML) classification allocates AML with t(8;21) RUNX1::RUNX1T1 fusion and AML with inv(16) or t(16;16) CBFB::MYH11 fusion (collectively, core-binding factor AML), AML with NPM1 without FLT3-ITD mutation and AML with CEBPA bZIP in-frame mutation into the favorable-risk strata based on initial molecular diagnostics. Generally, these entities have a relatively low risk of relapse (< 30%-40%) and many patients (> 50%-60%) survive long-term with intensive chemotherapy alone. However, there is growing literature that patterns of co-mutation, and more importantly, postremission measurable residual disease (MRD) status, modify these risks dynamically; necessitating an adaptive approach to optimize patient outcomes. In this review, we summarize evidence on how molecular and MRD features could assist clinicians in identifying high-risk patients within these favorable-risk subgroups, and where escalation of therapy, including with allogeneic transplantation in first remission, may be beneficial.
    Keywords:  CBFB::MYH11; CEBPA; NPM1; RUNX1::RUNX1T1; inv(16); t(8;21)
    DOI:  https://doi.org/10.1016/j.clml.2026.03.013
  6. Blood Adv. 2026 Apr 15. pii: bloodadvances.2025018908. [Epub ahead of print]
      Acute myeloid leukemia (AML) is an aggressive hematological malignancy that is sustained by leukemia-initiating cells (LICs). While PTP4A2 phosphatase, as known as PRL2, is highly expressed in AML, the mechanisms by which PTP4A2 promotes leukemogenesis are largely unexplored. In this study, we demonstrate that PTP4A2 promotes AML by inhibiting the p53 tumor suppressor pathway in LICs. Using KMT2A-MLLT3-driven AML as a model, we found that PTP4A2 deficiency activates p53 and induces LIC apoptosis and senescence, thereby extending the survival of recipient mice repopulated with Ptp4a2-/- LICs. Mechanistically, PTP4A2 directly interacts with p53 and dephosphorylates it at serine 392, decreasing p53 stability and activity to enhance LIC proliferation and survival. Collectively, our findings identify p53 as a potential PTP4A2 substrate in leukemia cells and uncover a novel mechanism by which PTP4A2 enhances LIC maintenance.
    DOI:  https://doi.org/10.1182/bloodadvances.2025018908
  7. Blood Cancer Discov. 2026 Apr 14.
      Fludarabine, cytarabine, and G-CSF-based therapy (FLAG) yields approximately 60% 5-year overall survival (OS) in core-binding factor (CBF) AML, with potential added benefit with gemtuzumab ozogamicin (GO). Although measurable residual disease status via optimal quantitative PCR response (OPR; qPCR <0.1% at end-of-induction, <0.01% during/after consolidation) of fusion-transcripts predicts survival, the impact of baseline myeloid mutations on OPR and survival, with FLAG remains uncertain. We interrogated these factors in 219 frontline patients with CBF-AML (median age 52 years; range 19-80) treated on a phase 2 trial (NCT00801489); 51% received FLAG-GO and 49% FLAG-idarubicin. Baseline mutations included 49% kinase-pathways (non-MAP kinase), 44% MAP-kinase, 11% DNMT3A-ASXL1-TET2 and 7% transcription-factors. Five-year relapse-free survival and OS were 67% and 74% overall; 77% and 80% with FLAG-GO. On multivariate analysis, baseline mutations did not affect OPR or survival, while FLAG-GO favored both. In CBF-AML, FLAG-based therapy possibly attenuates the prognostic impact of concurrent baseline genomics.
    DOI:  https://doi.org/10.1158/2643-3230.BCD-25-0477
  8. Commun Biol. 2026 Apr 14.
      The small GTPase RAN plays a role in the biogenesis of mature miR-126, which is supplied by the bone marrow arterioles to leukemic stem cells (LSCs). MiR-126 supports the homeostasis of LSCs that initiate and maintain acute myeloid leukemia (AML). While therapeutic targeting of RAN has been difficult due to its structural features, through molecular dynamics simulations and docking studies, we have identified MAR-3.6.2 as a novel allosteric inhibitor that binds in a cryptic pocket in the C-terminal domain of RAN. We showed that MAR-3.6.2 disrupted RAN interaction with its guanine nucleotide exchange factor RCC1 and prevented the nuclear switch of RAN-GDP to RAN-GTP. This in turn led to RAN nuclear retention and reduced the RAN/XPO5-mediated export of pre-miR-126, thereby limiting mature miR-126 biogenesis in endothelial cells and their exogenous supply of mature miR-126 to LSCs. In a MllPTD/WT/Flt3ITD/ITD AML murine model, MAR-3.6.2 reduced leukemia burden, prolonged survival, and decreased LSC frequency in secondary transplants. These findings highlight MAR-3.6.2 and future, potential derivatives as a promising small molecule-based approach to eradicate AML LSCs via inhibition of RAN/XPO5 trafficking and block of miR-126 biogenesis.
    DOI:  https://doi.org/10.1038/s42003-026-10026-0
  9. Blood. 2026 04 14. pii: blood.2025030579. [Epub ahead of print]
      Despite immunosensitivity, genetic heterogeneity, low mutational burden and lack of tumor-specific antigens hinder immunotherapy success for acute myeloid leukemia (AML). T cell receptors (TCRs) offer a promising route by targeting tumor-relevant extra- and intracellular antigens shared across AML subtypes; however human leukocyte antigen (HLA) restriction limits their potential. We identified a potent TCR capable of recognizing peptides of Cathepsin G (CTSG), a serine protease confined to neutrophil granules but aberrantly localized in the cytoplasm of blasts, when presented by HLA-A*24:02 and HLA-C*07:02, highly frequent alleles. Leveraging TCR gene-editing and CD8 co-receptor transduction, we engineered a robust T cell population, comprising CD4+ CD8+ T lymphocytes with enhanced functionality, without altering subset identity. T cells expressing the CTSG-TCR exhibited strong and specific cytotoxicity against primary blasts, in vitro and in vivo. Noticeably, no alterations in peripheral blood cell populations, bone marrow hematopoiesis, or extramedullary hematopoietic organs (spleen and liver) were observed, demonstrating optimal on-target/off-tumor safety profile. Moreover, the absence of off-target cross-reactivity was proved by peptide mutagenesis, highlighting the specificity of the TCR for CTSG. These results reveal the potential of dual restricted TCRs, and of CTSG-TCR T cells as powerful therapeutics for a broad AML patient population.
    DOI:  https://doi.org/10.1182/blood.2025030579
  10. Blood Cancer J. 2026 Apr 12.
      Contemporary risk models in chronic myelomonocytic leukemia (CMML) focus on the prognostic relevance of individual rather than concurrent mutations. In the current study of 605 Mayo Clinic patients with CMML, we applied machine-learning algorithms in order to examine the influence of cooperative mutational interactions on blast transformation (BT). A hierarchical clustering algorithm was developed and tailored for patient stratification using survival outcomes and co-occurrence of genomic alterations. Five molecular clusters were identified with 3-year blast BT rates ranging from 0% to 100% (AUC at 3 years 0.78). A subsequent Cox regression analysis confirmed independent detrimental impact of specific mutations or their combinations including NPM1 (HR 26.7; p < 0.01), "NRAS + SETBP1" (HR 12.6; p < 0.01), "ASXL1 + BCOR" (HR 8.4; p < 0.01), "ASXL1 + RUNX1" (HR 2.2, p < 0.01), JAK2 (HR 2.1; p < 0.01), and "ASXL1 + TET2" (HR 1.7; p = 0.02) while "PHF6+wild-type ASXL1" (HR 5.61e-10; p < 0.01) had a favorable impact. Furthermore, compared to NPM1 wild-type cases, NPM1-mutated patients were less likely to have co-occurring mutations involving ASXL1 (0% vs. 43%, p < 0.01), RUNX1 (0% vs. 17%, p = 0.02), and SRSF2 (7% vs. 39%, p < 0.01) and were more likely DNMT3A (71% vs. 7%, p < 0.01). The prognostic relevance of "NRAS + SETBP1", "ASXL1 + RUNX1", NPM1 and BCOR was validated in an external cohort from Italy (N = 501). Taken together, these observations highlight i) the possibility of prognostic interaction of mutations in CMML that should be considered in the development of future risk models and ii) the distinct genotypic and prognostic characteristics of NPM1-mutated CMML.
    DOI:  https://doi.org/10.1038/s41408-026-01491-1
  11. Nat Rev Clin Oncol. 2026 Apr 14.
      Myelodysplastic neoplasms, also known as myelodysplastic syndromes (MDS), are a heterogeneous group of myeloid malignancies characterized by ineffective haematopoiesis, cytopenias and a variably increased risk of progression to acute myeloid leukaemia. MDS primarily affect older adults with a median age at diagnosis of 76 years among patients in the USA. Despite major advances in our understanding of the genetic landscape and pathophysiology of MDS over the past 20 years, few disease-modifying therapies have been approved. Allogeneic haematopoietic stem cell transplantation remains the only potentially curative option. This slow therapeutic progress likely reflects the complex and widely heterogeneous pathophysiology of MDS, including a multifaceted interplay of somatic and germline mutations, a dysfunctional immune system, and an inflamed bone marrow microenvironment. Despite improvements in diagnostic tools, classification systems and prognostic models, these changes have introduced challenges for clinical trial design and epidemiological reporting. In this Review, we provide an update on the epidemiology, diagnosis, risk stratification, classification and expanding therapeutic armamentarium for the management of MDS. We also provide an overview of the current challenges to further progress and discuss future directions of research, which will hopefully lead to the development and approval of novel and effective therapies.
    DOI:  https://doi.org/10.1038/s41571-026-01141-2
  12. Leukemia. 2026 Apr 15.
      In allogeneic hematopoietic cell transplantation with post-transplant cyclophosphamide (PTCy), clinicians frequently face a critical choice between a readily available, often younger, haploidentical and a fully matched unrelated donor (MUD). The platform-specific influence of donor age on survival is a critical, unquantified factor that complicates clinical decision-making. We retrospectively analyzed 4258 adult patients with acute leukemia who underwent first allogeneic HCT with PTCy (2017-2021). We employed machine learning (Random Survival Forests and DeepSurv) alongside robust regression models, including Inverse Probability of Treatment Weighting, 1:1 Propensity Score Matching, and Elastic-Net penalized Cox regression. Machine learning models revealed a divergent association of donor age with survival depending on donor type. The MUD-PTCy platform proved remarkably resilient; a 1% absolute increase in mortality risk (equivalent to Number-Needed-to-Harm of 100) did not emerge in donors up to age 50. In stark contrast, the age-sensitive Haploidentical cohort reached this same risk threshold at a donor age of just 38 years. MUD-PTCy was independently associated with a significant overall survival advantage (Adjusted Hazard Ratio 0.85; 95% confidence interval, 0.75-0.97; P = 0.01). This analysis provides a quantitative framework to guide the trade-off between HLA matching and donor age, supporting individualized decision-making and a rationale to reconsider restrictive donor age policies.
    DOI:  https://doi.org/10.1038/s41375-026-02903-8
  13. Nat Rev Dis Primers. 2026 Apr 16. pii: 19. [Epub ahead of print]12(1):
      VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome is a disorder discovered in 2020 that bridges haematology, immunology and genetics. VEXAS syndrome arises from somatic mutations in UBA1, which encodes an E1 ubiquitin-activating enzyme, acquired in haematopoietic stem cells. These mutations disrupt ubiquitin-dependent protein homeostasis, triggering proteotoxic and inflammatory stress that drives systemic inflammation, cytopenias and clonal haematopoiesis. Clinically, VEXAS syndrome presents predominantly in older men with glucocorticoid-dependent inflammation, neutrophilic dermatoses, chondritis and myelodysplastic features. Diagnosis relies on characteristic clinical features and confirmation of UBA1 mutations. Prognosis is dismal in many patients, and treatment remains largely empirical. Glucocorticoids and cytokine blockade are used to provide transient control over inflammation, and hypomethylating agents aim to eradicate the mutant clone and induce disease remission. Allogeneic stem cell transplantation offers a potential cure. VEXAS syndrome exemplifies a new paradigm linking somatic genetics, inflammation and clonal haematopoiesis, reshaping our understanding of adult-onset inflammatory disease.
    DOI:  https://doi.org/10.1038/s41572-026-00695-w
  14. Bone Marrow Transplant. 2026 Apr 16.
      Philadelphia-negative myeloproliferative neoplasms (MPNs) can progress to blast phase (MPN-BP), a biologically distinct and highly lethal entity with a median survival typically under six months. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains the only potentially curative approach, yet relapse and non-relapse mortality limit durable benefit. We retrospectively analyzed post-transplant outcomes in 51 consecutive adults undergoing 53 allo-HSCTs for MPN-BP. Median age was 62 years; most cases evolved from myelofibrosis, and JAK2 was the predominant driver mutation. Neutrophil engraftment occurred in all but two patients (median 12 days). At 1-year, cumulative incidences were 35.8% for grade II-IV acute GVHD, 7.5% for moderate-severe chronic GVHD, 44.3% for relapse, and 25.8% for non-relapse mortality. One-year overall survival (OS) and disease-free survival were 43.4% and 37.7%, respectively; relapse was the leading cause of death. In multivariable analysis, TP53 mutations and higher peripheral blast burden adversely affected OS, while CALR mutations appeared to be associated with improved OS, peripheral blasts also independently predicted relapse. These data underscore the cure rate of approximately one-third of MPN-BP and highlight peripheral blasts and TP53 as actionable risk markers for transplant strategies.
    DOI:  https://doi.org/10.1038/s41409-026-02842-z
  15. Hemasphere. 2026 Apr;10(4): e70352
      Myelodysplastic neoplasms (MDSs) are clonal disorders characterized by ineffective hematopoiesis, dysplasia, and a risk of transformation into acute myeloid leukemia. MDS is also associated with a higher incidence of osteoporosis, suggesting a complex interplay between hematopoiesis, the bone marrow (BM) microenvironment, and bone homeostasis. Targeting inflammation has emerged as a promising therapeutic strategy, particularly in lower risk MDS. Tasquinimod (TASQ) is a small-molecule inhibitor of the inflammatory alarmin S100A9, blocking its interaction with TLR4 and RAGE receptors. We investigated the efficacy of TASQ in modulating inflammation and improving disease phenotype using in vitro and in vivo MDS models. Immunofluorescence staining of human BM identified neutrophils and macrophages as primary S100A9 sources. Exposure of mesenchymal stromal cells (MSCs) to S100A9 induced Toll-like receptor 4 (TLR4) downstream signaling, resulting in increased expression of IRAK1, NF-κB-p65, interleukin-1β (IL-1β), IL-18, caspase 1, and PD-L1. These effects were effectively abolished by TASQ. Additionally, TASQ restored the disturbed MSC-mediated hematopoietic support, as demonstrated by increased numbers of cobblestone area-forming cells and colony-forming units. In NHD13 MDS mice, TASQ (30 mg/kg, 12 weeks) improved hemoglobin and red blood cell counts, but exerted no effect in wild-type (WT) mice. Additionally, TASQ improved bone microarchitecture by increasing trabecular number and bone volume, likely a result of reduced osteoclast activity. Our findings suggest that TASQ mitigates inflammasome activation in the MDS BM, improving erythropoiesis and bone health. These results provide a necessary preclinical basis for clinical trials in lower risk MDS patients, in whom anemia and osteoporosis often coexist.
    DOI:  https://doi.org/10.1002/hem3.70352
  16. Semin Hematol. 2026 Mar 20. pii: S0037-1963(26)00022-3. [Epub ahead of print]
      Measurable residual disease (MRD) testing, high-sensitivity methods to estimate persistent leukemia below the threshold of conventional cytomorphological assessment, has the potential to transform the evaluation of treatment response, relapse prediction, and therapy development and selection for patients with acute myeloid leukemia (AML). Evidence accumulated over more than four decades demonstrates that patients testing MRD positive after treatment have substantially higher rates of relapse and inferior survival compared with those testing negative, but the heterogenous nature of the collection of diseases labeled as AML has resulted in slower clinical application and impact of such testing compared with other hematological malignancies. No single optimal universal AML MRD assay currently exists. The choice between imperfect AML MRD testing options requires explicit consideration of the evidence supporting a specific clinical context of use. Emerging technologies offer the prospect of improved sensitivity, specificity, and standardization, but most lack the prospective clinical validation required to guide practice change. Critically, beyond prognostication, it remains unproven in which clinical setting(s) therapeutic intervention guided by AML MRD results can improve overall survival. Updated clinical response criteria now recognize complete remission with MRD negativity as the optimal treatment response, and MRD status is increasingly integrated into clinical trial design, transplant decision-making, and drug development. Several large collaborative efforts, including prospective studies, are now generating the evidence needed to resolve fundamental questions in AML MRD regarding optimal assay selection, testing intervals, clinically meaningful thresholds, and surrogate endpoint validity. The coming years will determine whether AML MRD-guided therapy delivers measurable, patient-meaningful benefit.
    Keywords:  Acute Myeloid Leukemia (AML); Biomarkers; Generation Sequencing (NGS); Measurable Residual Disease (MRD); Next-Generation Sequencing (NGS); Prognostication
    DOI:  https://doi.org/10.1053/j.seminhematol.2026.03.009
  17. Eur J Pharmacol. 2026 Apr 15. pii: S0014-2999(26)00359-6. [Epub ahead of print] 178877
      FLT3 inhibitors have become a cornerstone in the treatment of FLT3-mutated acute myeloid leukemia (AML), however, durable clinical responses are frequently limited by the emergence of acquired resistance. In this study, we established and comprehensively characterized a quizartinib-resistant FLT3-ITD AML model to elucidate the molecular and functional mechanisms underlying therapeutic failure. Prolonged exposure of MV4-11 cells to escalating concentrations of quizartinib resulted in the selection of quizartinib resistant clones (MV4-11QR), displaying an increase in IC50 and a shift from cytotoxic to predominantly cytostatic responses. Resistant cells maintained MAPK signaling despite FLT3 inhibition. Global proteomic profiling revealed extensive reprogramming, with enrichment of pathways related to energy metabolism, RNA processing, and translational regulation, accompanied by enhanced mitochondrial respiration and glycolytic capacity. Whole-genome sequencing identified acquisition of the FLT3D835H mutation and clonal expansion of TP53R248W with loss of the wild-type TP53 allele, indicating strong treatment-driven clonal selection. Functionally, MV4-11QR cells showed broad cross-resistance to clinically relevant agents, including midostaurin, venetoclax, and cytarabine. Importantly, pharmacological targeting of mutant p53 with eprenetapopt or MAPK signaling with trametinib restored sensitivity to quizartinib, inducing synergistic or additive cytotoxic effects and increased apoptosis. Together, these findings define a multilayered resistance program involving genetic, signaling, and metabolic adaptations and support rational combination strategies to overcome FLT3 inhibitor resistance in AML.
    Keywords:  Acute myeloid leukemia; Clonal selection; FLT3 inhibitor resistance; Multidrug resistance; Quizartinib; TP53 mutation
    DOI:  https://doi.org/10.1016/j.ejphar.2026.178877
  18. Proc Natl Acad Sci U S A. 2026 Apr 21. 123(16): e2537987123
      Allogeneic hematopoietic cell transplantation is the only curative option for many patients with acute myeloid leukemia (AML). In the current study, we designed and implemented a personalized assay, called v96, incorporating up to 96 mutations in 30 AML patients undergoing transplantation. The assay was performed on DNA derived from cells isolated from the bone marrow as well as in cell-free plasma. All 30 (100%) of patients harbored molecular evidence of residual leukemia during remission that was detectable by the v96 assay, while only 6 (20%) had evidence of disease as assessed by conventional clinical assays. Furthermore, cell-free DNA from plasma proved to be more sensitive than DNA from cells of the bone marrow for identifying residual leukemia. The median number of mutants was 352-fold higher in plasma taken prior to transplantation for patients who relapsed compared to those who did not relapse. At 2 mo posttransplantation, 27 of the 30 patients still harbored detectable leukemia as assessed by the v96 assay. Twenty-two of these patients had a subsequent decrease in leukemic burden assessed by the v96 assay. In the majority of them (20 of 22 patients), the decrease occurred only after immunosuppression was discontinued, supporting a graft-versus-leukemia effect. These results document the feasibility of using a relatively large panel of carefully chosen mutations and a highly specific assay as noninvasive markers of therapeutic response in AML patients, minimizing the need for multiple bone marrow biopsies.
    Keywords:  acute myeloid leukemia; ctDNA; measurable residual disease
    DOI:  https://doi.org/10.1073/pnas.2537987123
  19. Biochem Biophys Res Commun. 2026 Apr 09. pii: S0006-291X(26)00516-4. [Epub ahead of print]817 153752
      Gemtuzumab ozogamicin (GO) is a humanized IgG4 anti-CD33 monoclonal antibody conjugated to the cytotoxic derivative of calicheamicin. GO was the first antibody-drug conjugate (ADC) approved for the treatment of patients with CD33+ acute myeloid leukemia (AML). Although GO exhibits cytotoxic activity against AML cells, its effectiveness may be limited by resistance mechanisms, highlighting the need to develop strategies that increase cell sensitivity to this ADC. In this study, we investigated whether inhibition of the anti-apoptotic protein BCL-2 and/or phosphatidylinositol 3 kinase (PI3K) pathway enhances GO-mediated cytotoxicity in AML cells with distinct phenotypes. Expectedly, GO decreased cell viability, induced G2/M arrest and apoptosis in leukemic cells. However, the degree of cellular response to GO differed among the four AML cell lines studied, indicating existence of resistant and sensitive cells, and this effect did not correlate with CD33 expression. We report that selective inhibition of BCL-2 and/or PI3K enhanced the pro-apoptotic effect of GO, both in GO-sensitive and GO-resistant AML cell lines. Importantly, the most pronounced effects were observed with the triple combination treatment, which successfully overcame GO resistance. Such inhibition caused cell line-dependent changes in the expression of apoptotic regulators, including BCL-2, MCL-1 and p53 protein, suggesting that cellular context shapes responses to combined treatments. In conclusion, our findings identify BCL-2 and PI3K inhibition as a promising new approach to sensitize AML cells to GO therapy, and highlight the importance of these pathways in determining the cellular response to gemtuzumab ozogamicin.
    Keywords:  ABT-199; Acute myeloid leukemia; BCL-2; PI3K/AKT signaling pathway; gemtuzumab ozogamicin
    DOI:  https://doi.org/10.1016/j.bbrc.2026.153752
  20. bioRxiv. 2026 Apr 12. pii: 2026.04.11.717967. [Epub ahead of print]
      Single-cell transcriptomics has revolutionized our understanding of heterogeneous cell populations. However, technical limitations of widely-used platforms have limited our ability to link transcriptional states to somatic mutations within the same cells at scale. Here, we introduce Genotyping in Fixed Transcriptomes (GIFT), a novel assay for simultaneous detection of hundreds of targeted genetic variants and whole transcriptome profiles in single cells. The core innovation of GIFT is a rationally designed gapfilling reaction between adjacent single-stranded DNA (ssDNA) probes that barcodes native transcript sequence to enable highly-specific targeted mutation detection. GIFT achieves >99% genotyping accuracy and flexible capture of hundreds of mutations per cell, including in FFPE (Formalin-Fixed Paraffin-Embedded) tissue, enabling clonal lineage tracing in heterogeneous settings. We demonstrate the unique scalability of GIFT by profiling >700,000 cells from 35 donors with myeloproliferative neoplasms (MPN), revealing mutation-dependent hematopoietic responses to systemic inflammation associated with the characteristic JAK2V617 mutation, including an allelic dose gradient of interferon-associated transcriptional programs and transcriptional priming of hematopoietic stem cells that develop into divergent disease states. Together, the unique technical advantages of GIFT enable direct resolution of genotype-to-phenotype relationships via clonal lineage tracing with comprehensive cell state measurements at single-cell resolution.
    DOI:  https://doi.org/10.64898/2026.04.11.717967
  21. Transplant Cell Ther. 2026 Apr 11. pii: S2666-6367(26)00257-5. [Epub ahead of print]
       BACKGROUND: Myeloid malignancies with TP53 alterations are characterized by genomic instability, chemotherapy resistance, and very poor outcomes even after allogeneic hematopoietic cell transplantation (allo-HCT). Hypomethylating agents (HMAs), small molecule targeted therapies, and donor lymphocyte infusion (DLI) are often used post-transplant to mitigate relapse risk in high-risk myeloid malignancies, but their impact on survival in TP53-mutated disease remains uncertain.
    OBJECTIVES: To evaluate the impact of post-transplant interventions and graft-versus-host disease (GVHD) on relapse and survival outcomes in patients with TP53-mutated or chromosomal 17p-deleted myeloid malignancies.
    STUDY DESIGN: This is a single-center retrospective study of adult patients with TP53-mutated and/or chromosomal 17p-deleted myeloid malignancies who underwent first allo-HCT between 2014 and 2023. Survival outcomes were assessed using the Kaplan-Meier method. Univariable Cox proportional hazards regression was used to assess associations of baseline characteristics with outcomes. Analyses of post-HCT interventions (maintenance/preemptive HMAs, targeted therapies, and/or DLI) and the development of chronic GVHD (classic chronic or acute/chronic overlap) were landmarked at 60 and 180 days, respectively, and both exposures were treated as time-dependent covariates. Cause-specific multivariable Cox proportional hazards regression models adjusted for baseline covariates were fitted to assess associations of outcomes with the time-dependent exposures. Pre-specified subgroup analyses were performed for the ultra-high-risk group, defined as complex karyotype and/or ≥2 TP53/17p alterations.
    RESULTS: Among 158 patients (median age 65 years, IQR: 57- 70), acute myeloid leukemia (54%) and myelodysplastic syndromes (40%) were the most common myeloid malignancies. Complex karyotypes were present in 68%, and ultra-high-risk features were present in 73%. Reduced-intensity conditioning was used in 59%. Approximately 49% of patients received post-HCT interventions; 68% of these were administered before relapse (preemptively or as prophylaxis/maintenance). In a landmark analysis at day 60 post-HCT (N=145), pre-relapse HMA, targeted therapies, and/or DLI was not associated with improved overall survival (OS) (HR 0.95; 95% CI: 0.56, 1.62; p=0.80), progression free survival (PFS) (HR 0.95; 95% CI: 0.49, 1.30; p=0.40), or cumulative incidence of relapse (CIR) (HR 1.05; 95% CI: 0.60, 1.85; p=0.90) after adjusting for key baseline characteristics. Similarly, in a landmark analysis at day 180 post-HCT (N=100), the occurrence of chronic GVHD was not associated with OS (HR 0.78; 95% CI: 0.24, 2.61; p=0.70), PFS (HR 0.67; 95% CI: 0.20, 2.23; p=0.50), or CIR (HR 0.34; 95% CI: 0.05, 2.54; p=0.30). Findings were similar in the ultra-high-risk subgroup (N=115) where post-HCT interventions showed no association with OS (HR 0.81; 95% CI: 0.45, 1.45; p=0.50), PFS (HR 0.72; 95% CI: 0.42, 1.24; p=0.20), or CIR (HR 0.87; 95% CI: 0.46, 1.62; p=0.70).
    CONCLUSIONS: In this single center study, preemptive or prophylactic post-HCT interventions did not significantly improve survival or reduce relapse risk in patients with TP53-altered myeloid malignancies, including those with ultra-high-risk features. While the study was limited by its small sample size and heterogeneous interventions, these findings highlight the urgent need to develop novel therapeutic strategies for this high-risk population.
    Keywords:  Chronic graft-versus-host disease; Donor lymphocyte infusion; Post-transplant maintenance therapy; Relapse prevention; TP53 mutant myeloid neoplasms
    DOI:  https://doi.org/10.1016/j.jtct.2026.03.039
  22. Br J Haematol. 2026 Apr 17.
      Mixed phenotype acute leukaemia (MPAL) is a rare subtype of acute leukaemia possessing significant therapeutic challenges, as no standardized, evidence-based treatment regimen has been defined. In this nationwide study, we aimed to assess the effect of an acute lymphoid leukaemia (ALL)-like regimen; an acute myeloid leukaemia (AML)-like regimen; and a hybrid regimen on complete remission (CR), overall survival (OS) and event-free survival (EFS). Patients were identified through the Danish National Pathology Registry and validated according to the 2022 WHO classification. OS was estimated using the Kaplan-Meier estimator, and differences in OS were assessed with the log-rank test. Inverse probability weighting was used to balance compared groups with respect to age and calendar year. Among the 43 intensively treated WHO 2022 MPAL patients, 25 (58.1%) received ALL regimens, 10 (23.3%) received AML regimens and 8 (18.6%) received hybrid regimens. CR rates by treatment regimen were highest for hybrid regimen (87.5% (95% confidence interval (CI): 47.3%-99.7)), followed by ALL regimen (72% (95% CI: 50.6%-87.5%)) and AML regimen (40% (95% CI: 12.2%-73.8%)). Treatment with hybrid regimens consisting of a fludarabine-based approach (fludarabine, cytarabine, G-CSF and idarubicin [FLAG-IDA], fludarabine, cytarabine, G-CSF and mitoxantrone [Mito-FLAG] or fludarabine, etoposide, G-CSF, mitoxantrone and cytarabine [FLEGMA]) was associated with improved OS and EFS compared to a classic daunorubicin-cytarabine AML regimen (p = 0.02 and p = 0.002 respectively).
    Keywords:  MPAL; mixed phenotype acute leukaemia
    DOI:  https://doi.org/10.1111/bjh.70491
  23. Leuk Res. 2026 Apr 08. pii: S0145-2126(26)00071-8. [Epub ahead of print]165 108227
       BACKGROUND: Despite recent advances in the treatment of acute myeloid leukemia (AML), primary refractory disease and relapse (R/R) remain frequent, and there is no clearly established standard of care in this setting. While the combination of hypomethylating agents (HMA) with venetoclax (VEN) is a standard front-line therapy for patient's ineligible for intensive chemotherapy, its efficacy in the R/R setting remains poorly defined. The purpose of this systematic review and meta-analysis was to review the efficacy and safety of HMA/VEN for management of R/R AML.
    METHODS: A systematic review was conducted using Embase and MEDLINE, identifying studies published between 2017 and 2025. Inclusion required adult R/R AML cohorts with at least 20 participants. The primary focus included treatment response and adverse events.
    RESULTS: A total of 32 studies (N = 2289) were included. Patients were heavily pretreated, with 34% of patients having prior HMA exposure. Pooled efficacy estimates showed: complete remission (CR) 26% (95% CI: 24-48%), composite CR (CR/CRi) 43% (95% CI: 41-46%), overall response rate (ORR) 50% (95% CI: 48-53%), and measurable residual disease (MRD) negativity 42% (95% CI: 38-46%). The median overall survival (OS) was 8 months (IQR: 3-25) with one-year OS 40% (IQR: 23-55). Safety concerns were notable, with significant grade ≥ 3 toxicities, including febrile neutropenia, infection, and cytopenia. No significant publication bias was observed.
    CONCLUSION: This study demonstrates that HMA/VEN is a potential re-induction regimen for patients with R/R AML. However, the high statistical heterogeneity identified underscores the need for further randomized studies to establish efficacy compared to more intensive salvage regimens.
    Keywords:  Acute myeloid leukemia; Hypomethylating agents; Refractory; Relapsed; Venetoclax
    DOI:  https://doi.org/10.1016/j.leukres.2026.108227
  24. Leukemia. 2026 Apr 14.
      Clonal hematopoiesis of indeterminate potential (CHIP) is associated with an elevated risk of hematologic and solid cancers. We performed a prospective cohort study, including 63690 patients with a first diagnosis of primary cancer in the UK Biobank during 2006 to 2022, to investigate the association of pre-diagnostic CHIP with future risk of second cancers. Cox regression was employed to assess the association between pre-diagnostic CHIP and risk of developing second cancer among patients with primary cancer. We identified 2860 patients with and 60626 without pre-diagnostic CHIP. During a median follow-up of 3.9 years, patients with primary cancer with pre-diagnostic CHIP experienced a greater risk of any second cancer (hazard ratio 1.3, 95% confidence intervals 1.2-1.5), compared with those without pre-diagnostic CHIP. Increased risk of any second cancer was mainly noted for patients with pre-diagnostic CHIP and primary myelodysplastic neoplasia, myeloproliferative neoplasms, non-Hodgkin lymphoma, or breast cancer. Regarding types of outcome (i.e., second cancer), the excess risk was particularly high for second myeloid malignancy and non-myeloid hematological malignancy. The risk for a second cancer was mainly observed in DNMT3A-, TET2-, SRSF2-, or JAK2-mutant CHIP. These findings suggest increased awareness of second cancer risk among patients with primary cancer and pre-diagnostic CHIP.
    DOI:  https://doi.org/10.1038/s41375-026-02946-x
  25. Clin Cancer Res. 2026 Apr 15.
       PURPOSE: Chimeric antigen receptor (CAR) T-cell immunotherapy in acute myeloid leukemia (AML) remains challenging due to the lack of specific cell surface antigens that are highly expressed on leukemic blasts but largely absent in hematopoietic stem/progenitor cells (HSPCs) and healthy tissues. Targeting intracellular antigen via TCR-like CAR-T cells offers a promising alternative. This study aimed to develop nanobodies targeting the intracellular antigen PRAME and develop a novel nanobody-based TCR-like CAR-T cell therapy.
    EXPERIMENTAL DESIGN: We investigated PRAME expression level by analyzing the RNA sequencing data from 1,007 AML patients and healthy donor samples. We explored the relationships between PRAME expression and the prognosis of AML. Novel nanobodies targeting PRAME425-433/HLA-A2 were generated via alpaca immunization and yeast surface display, then used to construct TCR-like CAR-T cells. The antileukemia potency of the PRAME-targeted TCR-like CAR-T cells and their on-target/off-tumor toxicity against normal HSPCs were evaluated.
    RESULTS: PRAME was highly expressed in AML cells but largely absent in normal hematopoietic cells and healthy tissues, and is correlated with poor clinical outcomes in AML. The CAR-T cells based on the nanobody targeting PRAME425-433/HLA-A2 exhibited specific and potent anti-leukemic cytotoxicity against PRAME+HLA-A2+ AML cells in vitro and in vivo, whereas they showed negligible effects on the viability and function of normal HSPCs.
    CONCLUSIONS: This study demonstrates that PRAME is a promising target for the immunotherapy of AML, and nanobody-based TCR-like CAR-T cells targeting PRAME425-433HLA-A2 exhibit potent anti-leukemic activity with a favorable off-target safety profile.
    DOI:  https://doi.org/10.1158/1078-0432.CCR-25-2726