Search Results (51)

Menin inhibitors are the first targeted therapies for KMT2A-rearranged and NPM1-mutated acute leukemias, addressing a significant unmet need in these high-risk subtypes. Revumenib received approval in 2024–2025 for relapsed or refractory KMT2A-rearranged acute leukemia and NPM1-mutated AML. The AUG-MENT-101 trial reported a 23% composite complete remission rate in heavily pretreated patients, with 61% of responders achieving MRD negativity. Several menin inhibitors, including ziftomenib, bleximenib, and enzomenib, are in clinical development. They demonstrate similar efficacy, but their safety profiles differ, especially regarding QTc prolongation and coverage of resistance mutations. Combination therapies with azacitidine and venetoclax or intensive chemotherapy have achieved high response rates in newly diagnosed patients, supporting their potential use in frontline treatment. Acquired resistance, often due to MEN1 mutations at the drug-binding interface, occurs in about 40% of cases. Distinct resistance patterns among menin inhibitors suggest the possibility of sequential therapy. Approximately 30–40% of responders in relapsed or refractory trials proceeded to allogeneic transplantation, which remains a key pathway to potential cure. This review examines the molecular mechanisms of the menin-KMT2A interaction, and summarizes clinical trial data on the efficacy and safety of menin inhibitors as monotherapy and in combination. Full article

Acute myeloid leukemia (AML) is a highly aggressive malignancy defined by significant biological diversity and variable patient outcomes. A key subset of AML is driven by abnormalities that lead to the overexpression of the oncogenic transcription factors HOXA9 and MEIS1. These abnormalities include KMT2A (formerly MLL) rearrangements and NPM1 mutations, as well as other rare lesions such as NUP98 rearrangements. This review focuses on the biology of the KMT2A, NPM1, and HOX/MEIS1 pathways, dissecting their molecular mechanisms of leukemogenesis. A central theme is the role of the scaffolding protein menin in the epigenetic regulation of this pathway, which ultimately drives malignant transformation. Currently, the clinical landscape is being transformed by the emergence of menin inhibitors as promising therapeutic agents for AML harboring these specific genetic anomalies. We evaluate the latest data on various menin inhibitors—both as monotherapy and in combinations—emphasizing their efficacy and safety profiles. As new evidence continues to accumulate with recent drug approvals and ongoing randomized, phase 3 studies, menin inhibitors are rapidly becoming a component of the AML treatment paradigm for relapsed/refractory and likely newly diagnosed disease. Full article

Background: The KMT2A (MLL1) gene is altered in a variety of hematological malignancies and solid tumors. KMT2A-rearranged (KMT2Ar) AML represents a distinct subtype associated with poor outcomes and high relapse rate despite initial responsiveness to chemotherapy. Methods: A total of 3863 cases of AML peripheral blood samples were analyzed using the FoundationOne Heme combined comprehensive hybrid capture-based DNA and RNA sequencing assay. Results: Of the 3863 AML cases, 521 (13.4%) featured genomic alterations (GAs) in the KMT2A gene, 99.1% of which were large rearrangements (KMT2Ar). A total of 56.9% were males with a median age of 62 years. Of the KMT2Ar cases, there were 43.1% KMT2A duplications, 52.7% fusions, and 4.2% not otherwise specified rearrangements. A total of 0.9% of the KMT2A-altered AML cases were short variant mutations. There were no KMT2A (0%) amplifications or deletions. KMT2Ar cases were associated with increased GA frequencies in FLT3 (27.3% vs. 19.8%; p = 0.0002), KRAS (17.2% vs. 7.8%; p < 0.0001) (overall; 1.1% KRAS G12C), and IDH2 (16.0% vs. 10.4%; p < 0.0001), while KMT2A wild-type AML (KMT2Awt) had significantly increased GA frequencies in RUNX1 (20.7% vs. 15.8%; p = 0.0081), ASXL1 (16.6% vs. 10.5%; p = 0.0003), and TET2 (16.4% vs. 10.1%; p = 0.0002), NPM1 (17.5% vs. 0.2%; p < 0.0001), and TP53 (17.8% vs. 7.9%; p < 0.0001). Conclusions: KMT2A rearrangements are common in AML (13.4% of cases featured KMT2Ar). A total of 99.1% of alterations in KMT2A are large rearrangements, with fusions being the most commonly observed alteration (52.7% of total rearrangements). No amplifications or deletions were seen. This genomic landscape study highlights significant genomic differences between KMT2Ar and KMT2Awt AML patients, which may enrich our understanding of the molecular profile and clusters of mutations in AML. Full article

Menin (MEN1) is a well-recognized powerful tumor promoter in acute leukemias (AL) with KMT2A rearrangements (KMT2Ar, also known as MLL) and mutant nucleophosmin 1 (NPM1m) acute myeloid leukemia (AML). MEN1 is essential for sustaining leukemic transformation due to its interaction with wild-type KMT2A and KMT2A fusion proteins, leading to the dysregulation of KMT2A target genes. MEN1 inhibitors (MIs), such as revumenib, ziftomenib, and other active small molecules, represent a promising new class of therapies currently under clinical development. By disrupting the MEN1-KMT2Ar complex, a group of proteins involved in chromatin remodeling, MIs induce apoptosis and differentiation AL expressing KMT2Ar or NPM1m AML. Phase I and II clinical trials have evaluated MIs as standalone treatments and combined them with other synergistic drugs, yielding promising results. These trials have demonstrated notable response rates with manageable toxicities. Among MIs, ziftomenib received orphan drug and breakthrough therapy designations from the European Medicines Agency in January 2024 and the Food and Drug Administration (FDA) in April 2024, respectively, for treating R/R patients with NPM1m AML. Additionally, in November 2024, the FDA approved revumenib for treating R/R patients with KMT2Ar-AL. This review focuses on the pathophysiology of MI-sensitive AL, primarily AML. It illustrates data from clinical trials and discusses the emergence of resistance mechanisms. In addition, we outline future directions for the use of MIs and emphasize the need for further research to fully realize the potential of these novel compounds, especially in the context of specific genetic subtypes of challenging AL. Full article

Background: In infant KMT2A (MLL1)-rearranged (MLL-r) acute lymphoblastic leukemia (ALL), early relapse and treatment response are currently monitored through invasive repeated bone marrow (BM) biopsies. Circulating tumor DNA (ctDNA) in peripheral blood (PB) provides a minimally invasive alternative, allowing for more frequent disease monitoring. However, a poor understanding of ctDNA dynamics has hampered its clinical translation. We explored the predictive value of ctDNA for detecting minimal/measurable residual disease (MRD) and drug response in a patient-derived xenograft (PDX) model of infant MLL-r ALL. Methods: Immune-deficient mice engrafted with three MLL-r ALL PDXs were monitored for ctDNA levels before and after treatment with the menin inhibitor SNDX-50469. Results: The amount of ctDNA detected strongly correlated with leukemia burden during initial engraftment prior to drug treatment. However, following SNDX-50469 treatment, the leukemic burden assessed by either PB leukemia cells through flow cytometry or ctDNA levels through droplet digital polymerase chain reaction (ddPCR) was discrepant. This divergence could be attributed to the persistence of leukemia cells in the spleen and BM, highlighting the ability of ctDNA to reflect disease dynamics in key leukemia infiltration sites. Conclusions: Notably, ctDNA analysis proved to be a superior predictor of MRD compared to PB assessment alone, especially in instances of low disease burden. These findings highlight the potential of ctDNA as a sensitive biomarker for monitoring treatment response and detecting MRD in infant MLL-r ALL. Full article

MLL-rearranged (MLLr) leukemia is characterized by a poor prognosis. Depending on the cell of origin, it differs in the aggressiveness and therapy response. For instance, in adults, volasertib blocking Polo-like kinase 1 (PLK-1) exhibited limited success. Otherwise, PLK-1 characterizes an infant MLLr signature, indicating potential sensitivity. By using our CRISPR/Cas9 MLLr model in CD34+ cells from human cord blood (huCB) and bone marrow (huBM) mimicking the infant and adult patient diseases, we were able to shed light on this phenomenon. The PLK-1 mRNA level was significantly increased in our huCB compared to the huBM model, which was underpinned by analyzing infant and adult MLLr leukemia patients. Importantly, the expression levels correlated with a functional response. Volasertib induced a significant dose-dependent decrease in proliferation and cell cycle arrest, most pronounced in the infant model. Mechanistically, upon volasertib treatment, we uncovered negative feedback only in the huBM model by compensatory upregulation of PLK-1 and related genes like AURKA involved in mitosis. Importantly, the poor response could be overcome by a combinatorial strategy with alisertib, an Aurora kinase A inhibitor. Our study emphasizes the importance of considering the cell of origin in therapeutic decision-making and provides the rationale for evaluating volasertib and alisertib in MLLr leukemia. Full article

Background: Although BRAF V600E mutations are common in solid tumors and select hematologic neoplasms, they are reported less frequently in myeloid malignancies. Of the cases of BRAF V600E-mutant acute myeloid leukemia (AML) that have been described, most display monocytic morphology and concurrent KMT2A rearrangement. Strikingly, all cases have been associated with poor survival. Case Presentation: Here, we report two cases of AML, one diagnosed in an elderly male with metastatic lung adenocarcinoma and hepatocellular carcinoma and the other diagnosed in a young boy previously treated for B-cell acute lymphoblastic leukemia. Peripheral blood NGS revealed oncogenic mutations in BRAF p.V600E (VAF = 33%), TET2 p.M508Cfs*25 (VAF = 48%), TET2 p.C211* (VAF = 49%), ZRSR2 p.R295* (VAF = 71%), BRAF p.N581S (VAF = 6%), and EZH2 c.118-2A>G, p.? (VAF = 4%) in case 1 and BRAF p.V600E (VAF = 1%) and KRAS p.G12A (VAF = 28%) in case 2. Cytogenetic workup revealed a complex karyotype in case 1 and an abnormal karyotype with non-clonal aberrations and KMT2A (MLL) rearrangement in case 2. Morphologically, both patients were found to have AML with monocytic features. The post-mortem examination of case 2 also revealed extensive solid organ infiltration, consistent with a monocytic leukemia. Both patients died within days of diagnosis, demonstrating the lethality of this molecular subgroup of AML. Conclusions: Our cases add to the literature, highlighting the poor prognosis of patients diagnosed with BRAF-mutant AML. Although it is uncertain whether the complex karyotype and somatic mutations observed in case 1 and KMT2A rearrangement and variants identified in case 2 may have either independently or cooperatively conferred a poor prognosis, we contend that additional comprehensive studies are needed to further understand the pathophysiology and prognosis of BRAF mutations in AML. We further posit whether patients with BRAF V600E-mutant AML may benefit from the combined use of BRAF inhibitors and/or RAS-pathway-targeting regimens, which are currently FDA-approved for the treatment of BRAF V600-mutant solid tumors and BRAF-mutant histiocytic neoplasms. Full article

KMT2A (alias: mixed-lineage leukemia [MLL]) gene mapping on chromosome 11q23 encodes the lysine-specific histone N-methyltransferase 2A and promotes transcription by inducing an open chromatin conformation. Numerous genomic breakpoints within the KMT2A gene have been reported in young children and adults with hematologic disorders and are present in up to 10% of acute leukemias. These rearrangements describe distinct features and worse prognosis depending on the fusion partner, characterized by chemotherapy resistance and high rates of relapse, with a progression-free survival of 30–40% and overall survival below 25%. Less intensive regimens are used in pediatric patients, while new combination therapies and targeted immunotherapeutic agents are being explored in adults. Beneficial therapeutic effects, and even cure, can be reached with hematopoietic stem cell transplantation, mainly in young children with dismal molecular lesions; however, delayed related toxicities represent a concern. Herein, we summarize the translocation partner genes and partial tandem duplications of the KMT2A gene, their molecular impact, clinical aspects, and novel targeted therapies. Full article

Inhibition of menin in acute myeloid leukemia (AML) harboring histone-lysine-N-methyltransferase 2A rearrangement (KMT2Ar) or the mutated Nucleophosmin gene (NPM1c) is considered a novel and effective treatment approach in these patients. However, rapid acquisition of resistance mutations can impair treatment success. In patients with elevated retinoic acid receptor alpha (RARA) expression levels, promising effects are demonstrated by the next-generation RARalpha agonist tamibarotene, which restores differentiation or induces apoptosis. In this study, the combination of revumenib and tamibarotene was investigated in various KMT2Ar or NPM1c AML cell lines and patient-derived blasts, focusing on the potential synergistic induction of differentiation or apoptosis. Both effects were analyzed by flow cytometry and validated by Western blot analysis. Synergy calculations were performed using viability assays. Regulation of the relevant key mediators for the MLL complex were quantified by RT-qPCR. In MV4:11 cells characterized by the highest relative mRNA levels of RARA, highly synergistic induction of apoptosis is demonstrated upon combination treatment. Induction of apoptosis by combined treatment of MV4:11 cells is accompanied by pronounced induction of the pro-apoptotic protein BAX and a synergistic reduction in CDK6 mRNA levels. In MOLM13 and OCI-AML3 cells, an increase in differentiation markers like PU.1 or a decreased ratio of phosphorylated to total CEBPA is demonstrated. In parts, corresponding effects were observed in patient-derived AML cells carrying either KMT2Ar or NPM1c. The impact of revumenib on KMT2Ar or NPM1c AML cells was significantly enhanced when combined with tamibarotene, demonstrating synergistic differentiation or apoptosis initiation. These findings propose promising strategies for relapsed/refractory AML patients with defined molecular characteristics. Full article

The transcriptional co-activator lens epithelium-derived growth factor/p75 (LEDGF/p75) plays an important role in the biology of the cell and in several human diseases, including MLL-rearranged acute leukemia, autoimmunity, and HIV-1 infection. In both health and disease, LEDGF/p75 functions as a chromatin tether that interacts with proteins such as MLL1 and HIV-1 integrase via its integrase-binding domain (IBD) and with chromatin through its N-terminal PWWP domain. Recently, dimerization of LEDGF/p75 was shown, mediated by a network of electrostatic contacts between amino acids from the IBD and the C-terminal α₆-helix. Here, we investigated the functional impact of LEDGF/p75 variants on the dimerization using biochemical and cellular interaction assays. The data demonstrate that the C-terminal α₆-helix folds back in cis on the IBD of monomeric LEDGF/p75. We discovered that the presence of DNA stimulates LEDGF/p75 dimerization. LEDGF/p75 dimerization enhances binding to MLL1 but not to HIV-1 integrase, a finding that was observed in vitro and validated in cell culture. Whereas HIV-1 replication was not dependent on LEDGF/p75 dimerization, colony formation of MLLr-dependent human leukemic THP-1 cells was. In conclusion, our data indicate that intricate changes in the quaternary structure of LEDGF/p75 modulate its tethering function. Full article

Menin/MEN1 is a scaffold protein that participates in proliferation, regulation of gene transcription, DNA damage repair, and signal transduction. In hematological malignancies harboring the KMT2A/MLL1 (MLLr) chromosomal rearrangements, the interaction of the oncogenic fusion protein MLLr with MEN1 has been shown to be essential. MEN1 binders inhibiting the MEN1 and KMT2A interaction have been shown to be effective against MLLr AML and B-ALL in experimental models and clinical studies. We hypothesized that in addition to the MEN1–KMT2A interaction, alternative mechanisms might be instrumental in the MEN1 dependency of leukemia. We first mined and analyzed data from publicly available gene expression databases, finding that the dependency of B-ALL cell lines on MEN1 did not correlate with the presence of MLLr. Using shRNA-mediated knockdown, we found that all tested B-ALL cell lines were sensitive to MEN1 depletion, independent of the underlying driver mutations. Most multiple myeloma cell lines that did not harbor MLLr were also sensitive to the genetic depletion of MEN1. We conclude that the oncogenic role of MEN1 is not limited to the interaction with KMT2A. Our results suggest that targeted degradation of MEN1 or the development of binders that induce global changes in the MEN1 protein structure may be more efficient than the inhibition of individual MEN1 protein interactions. Full article

The patient reported here underwent hematopoietic stem cell transplantation (HSCT) due to chronic granulomatous disease (CGD) caused by biallelic mutations of the NCF1 gene. Two years later, he developed AML, which was unexpected and was recognized via sex-mismatched chromosomes as deriving from the donor cells; the patient was male, and the donor was his sister. Donor cell leukemia (DCL) is very rare, and it had never been reported in patients with CGD after HSCT. In the subsequent ten years, the AML relapsed three times and the patient underwent chemotherapy and three further HSCTs; donors were the same sister from the first HSCT, an unrelated donor, and his mother. The patient died during the third relapse. The DCL was characterized since onset by an acquired translocation between chromosomes 9 and 11, with a molecular rearrangement between the MLL and MLLT3 genes—a quite frequent cause of AML. In all of the relapses, the malignant clone had XX sex chromosomes and this rearrangement, thus indicating that it was always the original clone derived from the transplanted sister’s cells. It exhibited the ability to remain quiescent in the BM during repeated chemotherapy courses, remission periods and HSCT. The leukemic clone then acquired different additional anomalies during the ten years of follow-up, with cytogenetic results characterized both by anomalies frequent in AML and by different, non-recurrent changes. This type of cytogenetic course is uncommon in AML. Full article

Chromosomal translocations involving the mixed lineage leukemia (MLL) gene cause 5–10% acute leukemias with poor clinical outcomes. Protein–protein interactions (PPI) between the most frequent MLL fusion partner proteins AF9/ENL and AF4 or histone methyltransferase DOT1L are drug targets for MLL-rearranged (MLL-r) leukemia. Several benzothiophene-carboxamide compounds were identified as novel inhibitors of these PPIs with IC₅₀ values as low as 1.6 μM. Structure–activity relationship studies of 77 benzothiophene and related indole and benzofuran compounds show that a 4-piperidin-1-ylphenyl or 4-pyrrolidin-1-ylphenyl substituent is essential for the activity. The inhibitors suppressed expression of MLL target genes HoxA9, Meis1 and Myc, and selectively inhibited proliferation of MLL-r and other acute myeloid leukemia cells with EC₅₀ values as low as 4.7 μM. These inhibitors are useful chemical probes for biological studies of AF9/ENL, as well as pharmacological leads for further drug development against MLL-r and other leukemias. Full article

MLL rearrangement (MLLr) is responsible for the development of acute leukemias with poor outcomes. Therefore, new therapeutic approaches are urgently needed. The NOTCH1 pathway plays a critical role in the pathogenesis of many cancers including acute leukemia. Using a CRISPR/Cas9 MLL-AF4/-AF9 translocation model, the newly developed NOTCH1 inhibitor CAD204520 with less toxic side effects allowed us to unravel the impact of NOTCH1 as a pathogenic driver and potential therapeutic target in MLLr leukemia. RNA sequencing (RNA-seq) and RT-qPCR of our MLLr model and MLLr cell lines showed the NOTCH1 pathway was overexpressed and activated. Strikingly, we confirmed this elevated expression level in leukemia patients. We also demonstrated that CAD204520 treatment of MLLr cells significantly reduces NOTCH1 and its target genes as well as NOTCH1 receptor expression. This was not observed with a comparable cytarabine treatment, indicating the specificity of the small molecule. Accordingly, treatment with CAD204520 resulted in dose-dependent reduced proliferation and viability, increased apoptosis, and the induction of cell cycle arrest via the downregulation of MLL and NOTCH1 target genes. In conclusion, our findings uncover the oncogenic relevance of the NOTCH1 pathway in MLLr leukemia. Its inhibition leads to specific anti-leukemic effects and paves the way for further evaluation in clinical settings. Full article

Infant acute myeloid leukemia (AML) is a heterogeneous disease, genetically distinct from its adult counterpart. Chromosomal translocations involving the KMT2A gene (MLL) are especially common in affected infants of less than 1 year of age, and are associated with a dismal prognosis. While these rearrangements are likely to arise in utero, the cell of origin has not been conclusively identified. This knowledge could lead to a better understanding of the biology of the disease and support the identification of new therapeutic vulnerabilities. Over the last few years, important progress in understanding the dynamics of fetal hematopoiesis has been made. Several reports have highlighted how hematopoietic stem cells (HSC) provide little contribution to fetal hematopoiesis, which is instead largely sustained by HSC-independent progenitors. Here, we used conditional Cre-Lox transgenic mouse models to engineer the Mll-Af9 translocation in defined subsets of embryonic hematopoietic progenitors. We show that embryonic hematopoiesis is generally permissive for Mll-Af9-induced leukemic transformation. Surprisingly, the selective introduction of Mll-Af9 in HSC-independent progenitors generated a transplantable myeloid leukemia, whereas it did not when introduced in embryonic HSC-derived cells. Ex vivo engineering of the Mll-Af9 rearrangement in HSC-independent progenitors using a CRISPR/Cas9-based approach resulted in the activation of an aberrant myeloid-biased self-renewal program. Overall, our results demonstrate that HSC-independent hematopoietic progenitors represent a permissive environment for Mll-Af9-induced leukemic transformation, and can likely act as cells of origin of infant AML. Full article