New directions for emerging therapies in acute myeloid leukemia: the next chapter

FLT3-selective PROTAC: Enhanced safety and increased synergy with Venetoclax in FLT3-ITD mutated acute myeloid leukemia

Acute myeloid leukemia (AML) patients carrying Fms-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) mutations often face a poor prognosis. While some FLT3 inhibitors have been used clinically, challenges such as short efficacy and poor specificity persist. Proteolytic targeting chimera (PROTAC), with its lower ligand affinity requirement for target proteins, offers higher and rapid targeting capability. Gilteritinib, used as the ligand for the target protein, was connected with different E3 ligase ligands to synthesize several series of PROTAC targeting FLT3-ITD. Through screening and structural optimization, the optimal lead compound PROTAC Z29 showed better specificity than Gilteritinib. Z29 induced FLT3 degradation through the proteasome pathway and inhibited tumor growth in subcutaneous xenograft mice. We verified Z29's minimal impact on platelets in a patient-derived xenografts (PDX) model compared to Gilteritinib. The combination of Z29 and Venetoclax showed better anti-tumor effects, lower platelet toxicity, and lower hepatic toxicity in FLT3-ITD+ models. The FLT3-selective PROTAC can mitigate the platelet toxicity of small molecule inhibitors, ensuring safety and efficacy in monotherapy and combination therapy with Venetoclax. It is a promising strategy for FLT3-ITD+ patients, especially those with platelet deficiency or liver damage.

Long-term hematopoietic transfer of the anti-cancer and lifespan-extending capabilities of a genetically engineered blood system by transplantation of bone marrow mononuclear cells

A causal relationship exists among the aging process, organ decay and disfunction, and the occurrence of various diseases including cancer. A genetically engineered mouse model, termed Klf1K74R/K74R or Klf1(K74R), carrying mutation on the well-conserved sumoylation site of the hematopoietic transcription factor KLF1/EKLF has been generated that possesses extended lifespan and healthy characteristics, including cancer resistance. We show that the healthy longevity characteristics of the Klf1(K74R) mice, as exemplified by their higher anti-cancer capability, are likely gender-, age-, and genetic background-independent. Significantly, the anti-cancer capability, in particular that against melanoma as well as hepatocellular carcinoma, and lifespan-extending property of Klf1(K74R) mice, could be transferred to wild-type mice via transplantation of their bone marrow mononuclear cells at a young age of the latter. Furthermore, NK(K74R) cells carry higher in vitro cancer cell-killing ability than wild-type NK cells. Targeted/global gene expression profiling analysis has identified changes in the expression of specific proteins, including the immune checkpoint factors PDCD and CD274, and cellular pathways in the leukocytes of the Klf1(K74R) that are in the directions of anti-cancer and/or anti-aging. This study demonstrates the feasibility of developing a transferable hematopoietic/blood system for long-term anti-cancer and, potentially, for anti-aging.

Ex vivo characterization of acute myeloid leukemia patients undergoing hypomethylating agents and venetoclax regimen reveals a venetoclax-specific effect on non-suppressive regulatory T cells and bona fide PD-1+TIM3+ exhausted CD8+ T cells

Acute myeloid leukemia (AML) is an aggressive heterogeneous disease characterized by several alterations of the immune system prompting disease progression and treatment response. The therapies available for AML can affect lymphocyte function, limiting the efficacy of immunotherapy while hindering leukemia-specific immune reactions. Recently, the treatment based on Venetoclax (VEN), a specific B-cell lymphoma 2 (BCL-2) inhibitor, in combination with hypomethylating agents (HMAs) or low-dose cytarabine, has emerged as a promising clinical strategy in AML. To better understand the immunological effect of VEN treatment, we characterized the phenotype and immune checkpoint (IC) receptors' expression on CD4+ and CD8+ T cells from AML patients after the first and second cycle of HMA in combination with VEN. HMA and VEN treatment significantly increased the percentage of naïve CD8+ T cells and TIM-3+ CD4+ and CD8+ T cells and reduced cytokine-secreting non-suppressive T regulatory cells (Tregs). Of note, a comparison between AML patients treated with HMA only and HMA in combination with VEN revealed the specific contribution of VEN in modulating the immune cell repertoire. Indeed, the reduction of cytokine-secreting non-suppressive Tregs, the increased TIM-3 expression on CD8+ T cells, and the reduced co-expression of PD-1 and TIM-3 on both CD4+ and CD8+ T cells are all VEN-specific. Collectively, our study shed light on immune modulation induced by VEN treatment, providing the rationale for a novel therapeutic combination of VEN and IC inhibitors in AML patients.

Non-coding RNAs in leukemia drug resistance: new perspectives on molecular mechanisms and signaling pathways

Like almost all cancer types, timely diagnosis is needed for leukemias to be effectively cured. Drug efflux, attenuated drug uptake, altered drug metabolism, and epigenetic alterations are just several of the key mechanisms by which drug resistance develops. All of these mechanisms are orchestrated by up- and downregulators, in which non-coding RNAs (ncRNAs) do not encode specific proteins in most cases; albeit, some of them have been found to exhibit the potential for protein-coding. Notwithstanding, ncRNAs are chiefly known for their contribution to the regulation of physiological processes, as well as the pathological ones, such as cell proliferation, apoptosis, and immune responses. Specifically, in the case of leukemia chemo-resistance, ncRNAs have been recognized to be responsible for modulating the initiation and progression of drug resistance. Herein, we comprehensively reviewed the role of ncRNAs, specifically its effect on molecular mechanisms and signaling pathways, in the development of leukemia drug resistance.

BCL-2 inhibition in haematological malignancies: Clinical application and complications

B-cell lymphoma-2 (BCL-2) family proteins are fundamental regulators of the intrinsic apoptotic pathway which modulate cellular fate. In many haematological malignancies, overexpression of anti-apoptotic factors (BCL-2, BCL-XL and MCL-1) circumvent apoptosis. To address this cancer hallmark, a concerted effort has been made to induce apoptosis by inhibiting BCL-2 family proteins. A series of highly selective BCL-2 homology 3 (BH3) domain mimetics are in clinical use and in ongoing clinical trials for acute myeloid leukaemia (AML), chronic myeloid leukaemia (CML), chronic lymphocytic leukaemia (CLL), and multiple myeloma (MM). These inhibitors serve as promising candidates, both as single agents or in combination therapy to improve patient outcomes. In other diseases such as follicular lymphoma, efficacy has been notably limited. There are also clinical problems with BCL-2 family inhibition, including drug resistance, disease relapse, tumour lysis syndrome, and clinically relevant cytopenias. Here, we provide a balanced view on both the clinical benefits of BCL-2 inhibition as well as the associated challenges.

Galectin-9, a pro-survival factor inducing immunosuppression, leukemic cell transformation and expansion

Leukemia is a malignancy of the bone marrow and blood originating from self-renewing cancerous immature blast cells or transformed leukocytes. Despite improvements in treatments, leukemia remains still a serious disease with poor prognosis because of disease heterogeneity, drug resistance and relapse. There is emerging evidence that differentially expression of co-signaling molecules play a critical role in tumor immune evasion. Galectin-9 (Gal-9) is one of the key proteins that leukemic cells express, secrete, and use to proliferate, self-renew, and survive. It also suppresses host immune responses controlled by T and NK cells, enabling leukemic cells to evade immune surveillance. The present review provides the molecular mechanisms of Gal-9-induced immune evasion in leukemia. Understanding the complex immune evasion machinery driven by Gal-9 expressing leukemic cells will enable the identification of novel therapeutic strategies for efficient immunotherapy in leukemic patients. Combined treatment approaches targeting T-cell immunoglobulin and mucin domain-3 (Tim-3)/Gal-9 and other immune checkpoint pathways can be considered, which may enhance the efficacy of host effector cells to attack leukemic cells.

Licochalcone A induces mitochondria-dependent apoptosis and interacts with venetoclax in acute myeloid leukemia

The management of patients with acute myeloid leukemia (AML) remains a challenge because of the complexity and heterogeneity of this malignancy. Despite the recent approval of several novel targeted drugs, resistance seems inevitable, and clinical outcomes are still suboptimal. Increasing evidence supports the use of natural plants as an important source of anti-leukemic therapeutics. Licochalcone A (LCA) is an active flavonoid isolated from the roots of licorice, Glycyrrhiza uralensis Fisch., possessing extensive anti-tumor activities. However, its effects on AML and the underlying mechanisms remain unknown. Here, we showed that LCA decreased the viability of established human AML cell lines in a dose- and time-dependent manner. LCA significantly induced mitochondrial apoptotic cell death, accompanied by the downregulation of MCL-1, upregulation of BIM, truncation of BID, and cleavage of PARP. A prominent decline in the phosphorylation of multiple critical molecules, including AKT, glycogen synthase kinase-3β (GSK3β), ERK, and P38 was observed upon LCA treatment, indicating PI3K and MAPK signals were suppressed. Both transcription and translation of c-Myc were also inhibited by LCA. In addition, LCA enhanced the cytotoxicity of the BCL-2 inhibitor venetoclax. Furthermore, the anti-survival and pro-apoptotic effects were confirmed in primary blasts from 10 patients with de novo AML. Thus, our results expand the applications of LCA, which can be regarded as a valuable agent in treating AML.

Designing patient-oriented combination therapies for acute myeloid leukemia based on efficacy/toxicity integration and bipartite network modeling

Acute myeloid leukemia (AML), a heterogeneous and aggressive blood cancer, does not respond well to single-drug therapy. A combination of drugs is required to effectively treat this disease. Computational models are critical for combination therapy discovery due to the tens of thousands of two-drug combinations, even with approved drugs. While predicting synergistic drugs is the focus of current methods, few consider drug efficacy and potential toxicity, which are crucial for treatment success. To find effective new drug candidates, we constructed a bipartite network using patient-derived tumor samples and drugs. The network is based on drug-response screening and summarizes all treatment response heterogeneity as drug response weights. This bipartite network is then projected onto the drug part, resulting in the drug similarity network. Distinct drug clusters were identified using community detection methods, each targeting different biological processes and pathways as revealed by enrichment and pathway analysis of the drugs' protein targets. Four drugs with the highest efficacy and lowest toxicity from each cluster were selected and tested for drug sensitivity using cell viability assays on various samples. Results show that ruxolitinib-ulixertinib and sapanisertib-LY3009120 are the most effective combinations with the least toxicity and the best synergistic effect on blast cells. These findings lay the foundation for personalized and successful AML therapies, ultimately leading to the development of drug combinations that can be used alongside standard first-line AML treatment.

Pivekimab sunirine (IMGN632), a novel CD123-targeting antibody-drug conjugate, in relapsed or refractory acute myeloid leukaemia: a phase 1/2 study

BACKGROUND

Pivekimab sunirine (IMGN632) is a first-in-class antibody-drug conjugate comprising a high-affinity CD123 antibody, cleavable linker, and novel indolinobenzodiazepine pseudodimer payload. CD123 is overexpressed in several haematological malignancies, including acute myeloid leukaemia. We present clinical data on pivekimab sunirine in relapsed or refractory acute myeloid leukaemia.

METHODS

This first-in-human, phase 1/2 dose-escalation and dose-expansion study enrolled participants aged 18 years or older at nine hospitals in France, Italy, Spain, and the USA with CD123+ haematological malignancies (Eastern Cooperative Oncology Group performance status of 0-1); participants reported here were in a cohort of participants with acute myeloid leukaemia who were refractory to or had relapsed on one or more previous treatments for acute myeloid leukaemia. The 3 + 3 dose-escalation phase evaluated two dosing schedules: schedule A (once every 3 weeks, on day 1 of a 3-week cycle) and fractionated schedule B (days 1, 4, and 8 of a 3-week cycle). The dose-expansion phase evaluated two cohorts: one cohort given 0·045 mg/kg of bodyweight (schedule A) and one cohort given 0·090 mg/kg of bodyweight (schedule A). The primary endpoints were the maximum tolerated dose and the recommended phase 2 dose. Antileukaemia activity (overall response and a composite complete remission assessment) was a secondary endpoint. The study is ongoing and registered with ClinicalTrials.gov, NCT03386513.

FINDINGS

Between Dec 29, 2017, and May 27, 2020, 91 participants were enrolled (schedule A, n=68; schedule B, n=23). 30 (44%) of schedule A participants were female and 38 (56%) were male; 60 (88%) were White, six (9%) were Black or African American, and two (3%) were other races. Pivekimab sunirine at doses of 0·015 mg/kg to 0·450 mg/kg in schedule A was administered in six escalating doses with no maximum tolerated dose defined; three dose-limiting toxicities were observed (reversible veno-occlusive disease; 0·180 mg/kg, n=1 and 0·450 mg/kg, n=1; and neutropenia; 0·300 mg/kg, n=1). Schedule B was not pursued further on the basis of comparative safety and antileukaemia findings with schedule A. The recommended phase 2 dose was selected as 0·045 mg/kg once every 3 weeks. At the recommended phase 2 dose (n=29), the most common grade 3 or worse treatment-related adverse events were febrile neutropenia (three [10%]), infusion-related reactions (two [7%]), and anaemia (two [7%]). Treatment-related serious adverse events occurring in 5% or more of participants treated at the recommended phase 2 dose were febrile neutropenia (two [7%]) and infusion-related reactions (two [7%]). Among 68 participants who received schedule A, one death (1%) was considered to be treatment-related (cause unknown; 0·300 mg/kg cohort). At the recommended phase 2 dose, the overall response rate was 21% (95% CI 8-40; six of 29) and the composite complete remission rate was 17% (95% CI 6-36; five of 29).

INTERPRETATION

Pivekimab sunirine showed single-agent activity across multiple doses, with a recommended phase 2 dose of 0·045 mg/kg once every 3 weeks. These findings led to a phase 1b/2 study of pivekimab sunirine plus azacitidine and venetoclax in patients with CD123-positive acute myeloid leukaemia.

FUNDING

ImmunoGen.

PD-1H/VISTA mediates immune evasion in acute myeloid leukemia

Acute myeloid leukemia (AML) presents a pressing medical need in that it is largely resistant to standard chemotherapy as well as modern therapeutics, such as targeted therapy and immunotherapy, including anti-programmed cell death protein (anti-PD) therapy. We demonstrate that programmed death-1 homolog (PD-1H), an immune coinhibitory molecule, is highly expressed in blasts from the bone marrow of AML patients, while normal myeloid cell subsets and T cells express PD-1H. In studies employing syngeneic and humanized AML mouse models, overexpression of PD-1H promoted the growth of AML cells, mainly by evading T cell-mediated immune responses. Importantly, ablation of AML cell-surface PD-1H by antibody blockade or genetic knockout significantly inhibited AML progression by promoting T cell activity. In addition, the genetic deletion of PD-1H from host normal myeloid cells inhibited AML progression, and the combination of PD-1H blockade with anti-PD therapy conferred a synergistic antileukemia effect. Our findings provide the basis for PD-1H as a potential therapeutic target for treating human AML.

Advantages of nanomedicine over the conventional treatment in Acute myeloid leukemia

Leukemia is a cancer of blood cells that mainly affects the white blood cells. In acute myeloid leukemia (AML) sudden growth of cancerous cells occurs in blood and bone marrow, and it disrupts normal blood cell production. Most patients are asymptomatic, but it spreads rapidly and can become fatal if left untreated. AML is the prevalent form of leukemia in children. Risk factors of AML include chemical exposure, radiation, genetics, etc. Conventional diagnostic methods of AML are complete blood count tests and bone marrow aspiration, while conventional treatment methods involve chemotherapy, radiation therapy, and bone marrow transplant. There is a risk of cancer cells spreading progressively to the other organs if left untreated, and hence, early diagnosis is required. The conventional diagnostic methods are time- consuming and have drawbacks like harmful side effects and recurrence of the disease. To overcome these difficulties, nanoparticles are employed in treating and diagnosing AML. These nanoparticles can be surface- modified and can be used against cancer cells. Due to their enhanced permeability effect and high surface-to-volume ratio they will be able to reach the tumour site which cannot be reached by traditional drugs. This review article talks about how nanotechnology is more advantageous over the traditional methods in the treatment and diagnosis of AML.

LncRNA LBX2-AS1 inhibits acute myeloid leukemia progression through miR-455-5p/MYLIP axis

Acute myeloid leukemia (AML) is a common blood cancer primarily affecting the bone marrow and blood cells, which is prevalent among adults. Long non-coding RNAs (lncRNAs) have been shown to play a crucial role in the development and progression of AML. LBX2-AS1 is a recently discovered lncRNA that has been linked to the pathogenesis and progression of several types of cancer. This study aimed to investigate the role and possible mechanisms of LBX2-AS1 in AML. Expression levels of LBX2-AS1, miR-455-5p, and their target genes were detected in AML samples and cells by RT-qPCR. Cell proliferation and apoptosis were determined by Cell Counting Kit-8 and 5-ethynyl-2'-deoxyuridine assays, and flow cytometry, respectively. LBX2-AS1 was downregulated in AML specimens and cells, and overexpression of LBX2-AS1 significantly inhibited cell proliferation and enhanced apoptosis in vitro. We also determined the effects of LBX2-AS1 overexpression in an AML mouse model by in vivo bioluminescence imaging. Mechanistically, LBX2-AS1 acts as a competitive endogenous RNA, which promotes myosin regulatory light chain interacting protein (MYLIP) expression by sponging miR-455-5p. Knockdown of MYLIP or upregulation of miR-455-5p antagonized the effect of LBX2-AS1 overexpression on the progression of AML. LBX2-AS1 may thus be a valuable therapeutic target for AML.

Generation of a new therapeutic D-peptide that induces the differentiation of acute myeloid leukemia cells through A TLR-2 signaling pathway

Acute myeloid leukemia (AML) is caused by clonal disorders of hematopoietic stem cells. Differentiation therapy is emerging as an important treatment modality for leukemia, given its less toxicity and wider applicable population, but the arsenal of differentiation-inducing agents is still very limited. In this study, we adapted a competitive peptide phage display platform to search for candidate peptides that could functionally induce human leukemia cell differentiation. A monoclonal phage (P6) and the corresponding peptide (pep-P6) were identified. Both L- and D-chirality of pep-P6 showed potent efficiency in inducing AML cell line differentiation, driving their morphologic maturation and upregulating the expression of macrophage markers and cytokines, including CD11b, CD14, IL-6, IL-1β, and TNF-α. In the THP-1 xenograft animal model, administration of D-pep-P6 was effective in inhibiting disease progression. Importantly, exposure to D-pep-P6 induced the differentiation of primary human leukemia cells isolated AML patients in a similar manner to the AML cell lines. Further mechanism study suggested that D-pep-P6 induced human leukemia cell differentiation by directly activating a TLR-2 signaling pathway. These findings identify a novel D-peptide that may promote leukemia differentiation therapy.

SOHO State of the Art Updates and Next Questions: Understanding and Overcoming Venetoclax Resistance in Hematologic Malignancies

The discovery of Venetoclax (VEN) has transformed the therapeutic landscape of acute myeloid leukemia (AML) and chronic lymphocytic leukemia (CLL). However, the response is heterogeneous with 10% to 50% of newly diagnosed AML patients not responding to hypomethylating agent (HMA) and VEN. Furthermore, up to 40% of responding patients relapse shortly. This review discusses the mechanism of action of Venetoclax and the major mechanisms of inherent and acquired resistance to VEN. VEN is highly specific to BCL-2 binding, as such other antiapoptotic proteins in BCL-2 family induce resistance. These antiapoptotic proteins can also be upregulated via a number of compensatory cell signaling pathways including PI3K/AKT/mTOR, the MAPK/ERK pathway, and mutant FLT3-ITD. Mutations can occur in BCL-2 and BAX proteins, or they can be silenced by TP53 mutations and other epigenetic changes. Changes to mitochondrial structure and metabolism can induce resistance. Key metabolic regulators include OXPHOS and alternative amino acid metabolism. Finally microenvironmental factors can influence VEN responses. This paper evaluates subsets of AML by differentiation, histology, cytogenetics and molecular markers and their different responses to VEN; with spliceosome mutations, ASXL1, NPM1 and IDH1/2 being favorable while others such as FLT3, TP53 and BCL-2 mutations being less responsive. Currently intensive multiagent chemotherapy and Venetoclax combinations such as 7+3+VEN are favored in fit younger AML patients. However, with resistant patients' subsets targeted combination therapies are becoming an increasingly attractive option. We explore the incorporation of non-BCL-2 inhibitors, next-generation BCL-2 and multi-protein agents, other inhibitors most prominently FLT-3 inhibitors in addition to Venetoclax, and other novel approaches for resolving Venetoclax resistance.

Outcomes after intensive chemotherapy for secondary and myeloid-related changes acute myeloid leukemia patients aged 60 to 75 years old: a retrospective analysis from the PETHEMA registry

Treatment options for patients with secondary acute myeloid leukemia (sAML) and AML with myeloid-related changes (AMLMRC) aged 60 to 75 years are scarce and unsuitable. A pivotal trial showed that CPX-351 improved complete remission with/without incomplete recovery (CR/CRi) and overall survival (OS) as compared with standard "3+7" regimens. We retrospectively analyze outcomes of 765 patients with sAML and AML-MRC aged 60 to 75 years treated with intensive chemotherapy, reported to the PETHEMA registry before CPX-351 became available. The CR/CRi rate was 48%, median OS was 7.6 months (95% confidence interval [CI]: 6.7-8.5) and event-free survival (EFS) 2.7 months (95% CI: 2-3.3), without differences between intensive chemotherapy regimens and AML type. Multivariate analyses identified age ≥70 years, Eastern Cooperative Oncology Group performance status ≥1 as independent adverse prognostic factors for CR/CRi and OS, while favorable/intermediate cytogenetic risk and NPM1 were favorable prognostic factors. Patients receiving allogeneic stem cell transplant (HSCT), autologous HSCT, and those who completed more consolidation cycles showed improved OS. This large study suggests that classical intensive chemotherapy could lead to similar CR/CRi rates with slightly shorter median OS than CPX-351.

m5 C regulator-mediated methylation modification patterns and tumor microenvironment infiltration characteristics in acute myeloid leukemia

BACKGROUND

Recently, many studies have been conducted to examine immune response modification at epigenetic level, but the candidate effect of RNA 5-methylcytosine (m5 C) modification on tumor microenvironment (TME) of acute myeloid leukemia (AML) is still unknown at present.

METHODS

We assessed the patterns of m5 C modification among 417 AML cases by using nine m5 C regulators. Thereafter, we associated those identified modification patterns with TME cell infiltration features. Additionally, stepwise regression and LASSO Cox regression analyses were conducted for quantifying patterns of m5 C modification among AML cases to establish the m5 C-score. Meanwhile, we validated the expression of genes in the m5C-score model by qRT-PCR. Finally, the present work analyzed the association between m5 C-score and AML clinical characteristics and prognostic outcomes.

RESULTS

In total, three different patterns of m5 C modification (m5 C-clusters) were identified, and highly differentiated TME cell infiltration features were also identified. On this basis, evaluating patterns of m5 C modification in single cancer samples was important for evaluating the immune/stromal activities in TME and for predicting prognosis. In addition, the m5 C-score was established, which showed a close relation with the overall survival (OS) of test and training set samples. Moreover, multivariate Cox analysis suggested that our constructed m5 C-score served as the independent predicting factor for the prognosis of AML (hazard ratio = 1.57, 95% confidence interval = 1.38-1.79, p < 1e-5 ).

CONCLUSIONS

This study shows that m5 C modification may be one of the key roles in the formation of diversity and complexity of TME. Meanwhile, assessing the patterns of m5 C modification among individual cancer samples is of great importance, which provides insights into cell infiltration features within TME, thereby helping to develop relevant immunotherapy and predict patient prognostic outcomes.

Targeting S100A9 protein affects mTOR-ER stress signaling and increases venetoclax sensitivity in Acute Myeloid Leukemia

Acute Myeloid Leukemia (AML) is a heterogeneous disease with limited treatment options and a high demand for novel targeted therapies. Since myeloid-related protein S100A9 is abundantly expressed in AML, we aimed to unravel the therapeutic impact and underlying mechanisms of targeting both intracellular and extracellular S100A9 protein in AML cell lines and primary patient samples. S100A9 silencing in AML cell lines resulted in increased apoptosis and reduced AML cell viability and proliferation. These therapeutic effects were associated with a decrease in mTOR and endoplasmic reticulum stress signaling. Comparable results on AML cell proliferation and mTOR signaling could be observed using the clinically available S100A9 inhibitor tasquinimod. Interestingly, while siRNA-mediated targeting of S100A9 affected both extracellular acidification and mitochondrial metabolism, tasquinimod only affected the mitochondrial function of AML cells. Finally, we found that S100A9-targeting approaches could significantly increase venetoclax sensitivity in AML cells, which was associated with a downregulation of BCL-2 and c-MYC in the combination group compared to single agent therapy. This study identifies S100A9 as a novel molecular target to treat AML and supports the therapeutic evaluation of tasquinimod in venetoclax-based regimens for AML patients.

Cytokine-Induced Memory-Like NK Cells: Emerging strategy for AML immunotherapy

Acute myeloid leukemia (AML) is a heterogeneous disease developed from the malignant expansion of myeloid precursor cells in the bone marrow and peripheral blood. The implementation of intensive chemotherapy and hematopoietic stem cell transplantation (HSCT) has improved outcomes associated with AML, but relapse, along with suboptimal outcomes, is still a common scenario. In the past few years, exploring new therapeutic strategies to optimize treatment outcomes has occurred rapidly. In this regard, natural killer (NK) cell-based immunotherapy has attracted clinical interest due to its critical role in immunosurveillance and their capabilities to target AML blasts. NK cells are cytotoxic innate lymphoid cells that mediate anti-viral and anti-tumor responses by producing pro-inflammatory cytokines and directly inducing cytotoxicity. Although NK cells are well known as short-lived innate immune cells with non-specific responses that have limited their clinical applications, the discovery of cytokine-induced memory-like (CIML) NK cells could overcome these challenges. NK cells pre-activated with the cytokine combination IL-12/15/18 achieved a long-term life span with adaptive immunity characteristics, termed CIML-NK cells. Previous studies documented that using CIML-NK cells in cancer treatment is safe and results in promising outcomes. This review highlights the current application, challenges, and opportunities of CIML-NK cell-based therapy in AML.

Anti-leukemia effects of omipalisib in acute myeloid leukemia: inhibition of PI3K/AKT/mTOR signaling and suppression of mitochondrial biogenesis

Omipalisib (GSK2126458), a potent dual PI3K/mTOR inhibitor, is reported to exhibit anti-tumor effect in several kinds of cancers. More than 50% of acute myeloid leukemia (AML) patients display a hyperactivation of PI3K/AKT/mTOR signaling. We investigated the anti-proliferative effect of omipalisib in AML cell lines with varied genetic backgrounds. The OCI-AML3 and THP-1 cell lines had a significant response to omipalisib, with IC50 values of 17.45 nM and 8.93 nM, respectively. We integrated transcriptomic profile and metabolomic analyses, and followed by gene set enrichment analysis (GSEA) and metabolite enrichment analysis. Our findings showed that in addition to inhibiting PI3K/AKT/mTOR signaling and inducing cell cycle arrest at the G0/G1 phase, omipalisib also suppressed mitochondrial respiration and biogenesis. Furthermore, omipalisib downregulated several genes associated with serine, glycine, threonine, and glutathione metabolism, and decreased their protein and glutathione levels. In vivo experiments revealed that omipalisib significantly inhibited tumor growth and prolonged mouse survival without weight loss. Gedatolisib and dactolisib, another two PI3K/mTOR inhibitors, exerted similar effects without affecting mitochondria biogenesis. These results highlight the multifaceted anti-leukemic effect of omipalisib, revealing its potential as a novel therapeutic agent in AML treatment.

MiR-455-3p mediates PPARα through UBN2 to promote apoptosis and autophagy in acute myeloid leukemia cells

Acute myeloid leukemia (AML) is one of the deadliest hematologic malignancies, and its targeted therapy has developed slowly. The molecular mechanism of the pathophysiology of the disease remains to be clarified. The aim of our study was to probe the specific regulatory mechanism of miR-455-3p in AML. This study measured the levels of miR-455-3p and ubinuclein-2 (UBN2) in AML cell lines, evaluated cell viability with CCK-8, used flow cytometry to estimate the cell cycle and apoptosis, detected cell apoptosis and autophagy-related protein levels by Western blotting, and added 50 μM chloroquine (CQ) to evaluate the relationship between autophagy and AML. In animal experiments, HL-60 cells were injected into male non-obese diabetic/severe combined immunodeficiency disease (NOD/SCID) mice through the tail vein to determine survival time and observe the degree of liver and spleen damage in the mice. miR-455-3p was prominently reduced in the peripheral blood and AML cell lines, and UBN2 showed high expression. The transfected miR-455-3p mimic effectively restrained the activity of AML cells, whereas overexpression of UBN2 or the addition of the autophagy inhibitor CQ reversed the effect of miR-455-3p. The interaction between UBN2 and peroxisome proliferator-activated receptor alpha (PPARα) was confirmed by coimmunoprecipitation, and overexpression of PPARα reversed the promoting effect of UBN2 knockdown on apoptosis and autophagy in AML cells. In conclusion, miR-455-3p mediates PPARα protein expression through UBN2, exacerbating AML cell apoptosis and autophagy. This study found that miR-455-3p plays an important role in AML cell apoptosis and autophagy, which may provide novel insights for the treatment of AML diseases.

[How did the survival of acute myeloid leukemia change over the last ten years in our unit?]

INTRODUCTION

Acute myeloid leukemia (AML) is a hematological malignancy with high mortality rate. The treatment is especially challenging in patients older than 65 years, which is the large majority of those. For patients unfit for intensive chemotherapy regimens, only palliative cytoreduction and basic supportive care used to be the options in our unit. However, from 2018, the azacitidine-venetoclax combination has been a new therapeutic alternative. This treatment resulted in marked survival benefit in clinical trials, however, its impact on the daily clinical practice and the entire patient population is unclear.

OBJECTIVE

Our goal was to evaluate how the application of azacitidine-venetoclax changed the treatment and survival of AML patients in our practice.

METHOD

We retrospectively analyzed the available clinical data of all AML patients treated consecutively between January 1, 2011 and December 31, 2021 at the 3rd Department of Internal Medicine (from 2020 onward called Department of Internal Medicine and Hematology), examining their treatment depending on the time period of therapy (2011-2017 and 2018-2021). Patients with acute promyelocytic leukemia were excluded.

RESULTS

423 patients were diagnosed during this period. The number of cases showed a marked increase: in the first 7 years of our study, 184 patients were diagnosed, while this rose to 239 during the subsequent 4 years. The median age of patients was 67.6 years, with more than 60% of patients aged over 65. An improving trend can be observed in the overall survival: between 2011 and 2017, the median overall survival was 4.8 ± 0.9 months, while between 2018 and 2021, it was 8.3 ± 1.4 months (p = 0.051). Moreover, in the case of patients over 65 there was a significant overall survival improvement: 3.1 ± 0.5 vs. 4.9 ± 0.6 months (p = 0,01). The main factor behind this improvement could be that a large proportion of over 65 patients previously only fit for supportive care could now be treated with azacitidine-venetoclax: the percentage of actively treated patients grew from 57.1% to 75.3% in the second period.

CONCLUSION

The survival of patients unfit for curative therapy and older than 65 showed a steady increase which can be attributed to the introduction of new therapeutic alternatives. Orv Hetil. 2023; 164(45): 1787-1794.

Impact of different chemotherapy regimens on intestinal mucosal injury assessed with bedside ultrasound: a study in 213 AML patients

Introduction

Neutropenic enterocolitis (NEC) is a life-threatening complication reported in patients with acute myeloid leukemia (AML) following chemotherapy (CHT). Intensive induction and consolidation CHT may damage intestinal mucosa leading to a NEC episode (NECe). NEC reported mortality may be up to 30-60%. Early US-guided bed-side diagnosis and prompt treatment may substantially improve the survival. An emerging worldwide concern is the intestinal colonization by multi-drug-resistant bacteria especially when patients are exposed to chemotherapy regimens potentially correlated to mucosal damage.

Methods

In our study we prospectively enrolled all AML patients admitted in our leukemia unit to receive intensive induction and consolidation chemotherapy and experiencing chemotherapy-induced-neutropenia (CHTN).

Results and discussion

Overall, we enrolled N=213 patients from 2007 to March 2023. We recorded N=465 CHTN, and N=42 NECe (9.0% incidence). The aim of our study was to assess which chemotherapy regimens are more associated with NEC. We found that ALM1310, followed by 7 + 3 (daunorubicin), 7 + 3 (idarubicin), 5 + 3 + 3 (cytarabine, etoposide, idarubicin), and AML1310 (consolidation) were associated with a statistically higher incidence of NEC. We did not detect NEC episodes in patients treated with CPX-351, 5 + 2 (cytarabine, idarubicine), and high-dose cytarabine. Thus, we found that cytarabine could determine mucosal damage when associated with an anthracycline but not if delivered either alone or as dual-drug liposomal encapsulation of daunorubicin/cytarabine. We also describe NEC mortality, symptoms at diagnosis, intestinal sites involvement, and prognostic significance of bowel wall thickening.

Paralog-specific signaling by IRAK1/4 maintains MyD88-independent functions in MDS/AML

Dysregulation of innate immune signaling is a hallmark of hematologic malignancies. Recent therapeutic efforts to subvert aberrant innate immune signaling in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) have focused on the kinase IRAK4. IRAK4 inhibitors have achieved promising, though moderate, responses in preclinical studies and clinical trials for MDS and AML. The reasons underlying the limited responses to IRAK4 inhibitors remain unknown. In this study, we reveal that inhibiting IRAK4 in leukemic cells elicits functional complementation and compensation by its paralog, IRAK1. Using genetic approaches, we demonstrate that cotargeting IRAK1 and IRAK4 is required to suppress leukemic stem/progenitor cell (LSPC) function and induce differentiation in cell lines and patient-derived cells. Although IRAK1 and IRAK4 are presumed to function primarily downstream of the proximal adapter MyD88, we found that complementary and compensatory IRAK1 and IRAK4 dependencies in MDS/AML occur via noncanonical MyD88-independent pathways. Genomic and proteomic analyses revealed that IRAK1 and IRAK4 preserve the undifferentiated state of MDS/AML LSPCs by coordinating a network of pathways, including ones that converge on the polycomb repressive complex 2 complex and JAK-STAT signaling. To translate these findings, we implemented a structure-based design of a potent and selective dual IRAK1 and IRAK4 inhibitor KME-2780. MDS/AML cell lines and patient-derived samples showed significant suppression of LSPCs in xenograft and in vitro studies when treated with KME-2780 as compared with selective IRAK4 inhibitors. Our results provide a mechanistic basis and rationale for cotargeting IRAK1 and IRAK4 for the treatment of cancers, including MDS/AML.

Ivosidenib in acute myeloid leukemia

INTRODUCTION

Traditional treatment strategies for acute myeloid leukemia (AML) have primarily relied on standard chemotherapy regimens for four decades. Indeed, the landscape of AML therapy has evolved substantially in recent years, mainly due to the introduction of hypomethylating agents and small molecules.Bcl2 inhibitor venetoclax, Fms-like tyrosine kinase 3 (FLT3) inhibitors such as midostaurin and gilteritinib, and isocitrate dehydrogenases 1 and 2 (IDH1 and IDH2) inhibitors ivosidenib and enasidenib, as well as hedgehog (HH) pathway inhibitor glasdegib represented a significant step forward in AML therapeutic armamentarium. Smoothened (SMO) inhibitor in combination with low-dose cytarabine marks a recent milestone.

AREAS COVERED

Ivosidenib, the first-in-class, selective, allosteric IDH1R132 inhibitor, showed the capability to induce in vitro differentiation of primary mIDH1 AML blasts. Clinical data highlighted its exceptional safety profile, as a standalone therapy and in combination strategy. Additionally, comprehensive studies consistently demonstrated its effectiveness, both in monotherapy and in association with chemotherapy.

EXPERT OPINION

The identified ivosidenib's strengths, including its remarkable safety record and ability to yield positive therapeutic outcomes, position it as an ideal partner for both classic chemotherapy and biological treatments, i.e. hypometilant agents and/or venetoclax. Further studies are warranted to explore strategies for overcoming the occurrence of ivosidenib resistance.

Real-world genomic testing and treatment patterns of newly diagnosed adult acute myeloid leukemia patients within a comprehensive health system

BACKGROUND

We evaluated the frequency of genomic testing and treatment patterns by age category in patients with newly diagnosed (ND) acute myeloid leukemia (AML) treated in both academic- and community-based health systems within a single Midwestern State.

METHODS

Retrospective analysis of data from the Indiana University Health System Enterprise Data Warehouse and two local cancer registries, of 629 patients aged ≥18 years with ND AML during 2011-2018. Primary outcome variables were, proportion of patients with genomic analysis and frequency of mutations. Chemotherapy was categorized as "standard induction" or "other chemotherapy"/targeted therapy, and hypomethylating agents.

RESULTS

Overall, 13% of ND AML patients between 2011 and 2018 had evidence of a genomic sequencing report with a demonstrated increase to 37% since 2016. Genomic testing was more likely performed in patients: aged ≤60 years than >60 years (45% vs. 30%; p = 0.03), treated in academic versus community hospitals (44% vs. 26%; p = 0.01), and in chemotherapy recipients than non-therapy recipients (46% vs. 19%; p < 0.001). Most common mutations were ASXL1, NPM1, and FLT3. Patients ≥75 years had highest proportion (46%) of multiple (≥3) mutations. Overall, 31.2% of patients with AML did not receive any therapy for their disease. This subgroup was older than chemotherapy recipients (mean age: 71.4 vs. 55.7 years, p < 0.001), and was highest (66.2%) in patients ≥75 years.

CONCLUSIONS

Our results highlight the unmet medical need to increase access to genomic testing to afford treatment options, particularly to older AML patients in the real-world setting, in this new era of targeted therapies.

Discovery of Small-Molecule TIM-3 Inhibitors for Acute Myeloid Leukemia Using Pharmacophore-Based Virtual Screening

T-cell immunoglobulin and mucin domain 3 (TIM-3) is a negative immune checkpoint that represents a promising target for cancer immunotherapy. Although encouraging results have been observed for TIM-3 inhibition in the context of acute myeloid leukemia (AML), targeting TIM-3 is currently restricted to monoclonal antibodies (mAbs). To fill this gap, we implemented a pharmacophore-based screening approach to identify small-molecule TIM-3 inhibitors. Our approach resulted in the identification of hit compounds with TIM-3 binding affinity. Subsequently, we used the structure-activity relationship (SAR) by a catalog approach to identify compound A-41 with submicromolar TIM-3 binding affinity. Remarkably, A-41 demonstrated the ability to block TIM-3 interactions with key ligands and inhibited the immunosuppressive function of TIM-3 using an in vitro coculture assay. This work will pave the way for future drug discovery efforts aiming at the development of small-molecule inhibitors TIM-3 for AML.

Transcriptional Response to Standard AML Drugs Identifies Synergistic Combinations

Unlike genomic alterations, gene expression profiles have not been widely used to refine cancer therapies. We analyzed transcriptional changes in acute myeloid leukemia (AML) cell lines in response to standard first-line AML drugs cytarabine and daunorubicin by means of RNA sequencing. Those changes were highly cell- and treatment-specific. By comparing the changes unique to treatment-sensitive and treatment-resistant AML cells, we enriched for treatment-relevant genes. Those genes were associated with drug response-specific pathways, including calcium ion-dependent exocytosis and chromatin remodeling. Pharmacological mimicking of those changes using EGFR and MEK inhibitors enhanced the response to daunorubicin with minimum standalone cytotoxicity. The synergistic response was observed even in the cell lines beyond those used for the discovery, including a primary AML sample. Additionally, publicly available cytotoxicity data confirmed the synergistic effect of EGFR inhibitors in combination with daunorubicin in all 60 investigated cancer cell lines. In conclusion, we demonstrate the utility of treatment-evoked gene expression changes to formulate rational drug combinations. This approach could improve the standard AML therapy, especially in older patients.

Posttranslational splicing modifications as a key mechanism in cytarabine resistance in acute myeloid leukemia

Despite the approval of several drugs for AML, cytarabine is still widely used as a therapeutic approach. However, 85% of patients show resistance and only 10% overcome the disease. Using RNA-seq and phosphoproteomics, we show that RNA splicing and serine-arginine-rich (SR) proteins phosphorylation were altered during cytarabine resistance. Moreover, phosphorylation of SR proteins at diagnosis were significantly lower in responder than non-responder patients, pointing to their utility to predict response. These changes correlated with altered transcriptomic profiles of SR protein target genes. Notably, splicing inhibitors were therapeutically effective in treating sensitive and resistant AML cells as monotherapy or combination with other approved drugs. H3B-8800 and venetoclax combination showed the best efficacy in vitro, demonstrating synergistic effects in patient samples and no toxicity in healthy hematopoietic progenitors. Our results establish that RNA splicing inhibition, alone or combined with venetoclax, could be useful for the treatment of newly diagnosed or relapsed/refractory AML.

Novel covalent CDK7 inhibitor potently induces apoptosis in acute myeloid leukemia and synergizes with Venetoclax

INTRODUCTION

The emergence of resistance to the highly successful BCL2-directed therapy is a major unmet need in acute myeloid leukemia (AML), an aggressive malignancy with poor survival rates. Towards identifying therapeutic options for AML patients who progress on BCL2-directed therapy, we studied a clinical-stage CDK7 inhibitor XL102, which is being evaluated in solid tumors (NCT04726332).

MATERIALS AND METHODS

To determine the anti-proliferative effects of XL102, we performed experiments including time-resolved fluorescence resonance energy transfer, target occupancy, cell cycle and apoptosis-based assays. We also included genetically characterized primary myeloid blasts from de novo and relapsed/refractory AML patients. For mechanistic studies, CRISPR/Cas9 mediated knockout of CDK7 and c-Myc and immunoblotting were performed. NOD/SCID orthotropic and subcutaneous AML xenografts were used to determine anti-leukemic effects. To assess the synergistic effects of XL102 with Venetoclax, we performed RNA sequencing and gene set enrichment analysis using Venetoclax sensitive and resistant model systems.

RESULTS

XL102, a highly specific, orally bioavailable covalent inhibitor of CDK7. Inhibitory effect on CDK7 by XL102 in primary myeloid blasts (n = 54) was in nanomolar range (mean = 300 nM; range = 4.0-952 nM). XL102 treated AML cells showed a reduction in phosphorylation levels of Serine 2/5/7 at carboxy-terminal domain of RNA polymerase II. T-loop phosphorylation of CDK1(Thr161) and CDK2(Thr160) was inhibited by XL102 in dose-dependent manner leading to cell-cycle arrest. c-Myc downregulation and enhanced levels of p53 and p21 in XL102 treated cells were observed. Increased levels of p21 and activation of p53 by XL102 were mimicked by genetic ablation of CDK7, which supports that the observed effects of XL102 are due to CDK7 inhibition. XL102 treated AML xenografts showed remarkable reduction in hCD45 + marrow cells (mean = 0.60%; range = 0.04%-3.53%) compared to vehicle control (mean = 38.2%; range = 10.1%-78%), with corresponding increase in p53, p21 and decrease in c-Myc levels. The data suggests XL102 induces apoptosis in AML cells via CDK7/c-Myc/p53 axis. RNA-sequencing from paired Venetoclax-sensitive and Venetoclax-resistant cells treated with XL102 showed downregulation of genes involved in proliferation and apoptosis.

CONCLUSION

Taken together, XL102 with Venetoclax led to synergistic effects in overcoming resistance and provided a strong rationale for clinical evaluation of XL102 as a single agent and in combination with Venetoclax.

Exploration of cuprotosis-related genes for predicting prognosis and immunological characteristics in acute myeloid leukaemia based on genome and transcriptome

BACKGROUND

Acute myeloid leukemia (AML) is a common hematologic malignancy with a generally unfavorable prognosis. Cuprotosis as a new form of programmed cell death has been shown to play an important role in tumorigenesis and progression; However, the relationship between cuprotosis and the prognosis of AML patients remains unclear.

METHODS

Transcriptomic and genomics data, along with clinical information, were obtained from the TCGA and GEO databases. Especially, unsupervised clustering and machining learning were used to identify molecular subtypes and cuprotosis-related risk scores respectively. Kaplan-Meier analysis, univariate and multivariate Cox regression, and Receiver Operator Characteristic curve (ROC) were performed to assess the prognosis based on cuprotosis-related genes (CRGs). Moreover, multiple algorithms were used to evaluate immunological heterogeneity among patients with different risk scores. For in vitro analysis, the expression of genes involved in CRGs was detected by Quantitative Reverse Transcription Polymerase (qRT-PCR) in AML patients.

RESULTS

Transcriptomic and genome data indicated the immense heterogeneity in the CRGs landscape of normal and tumor samples. Cuprotosis subtype A and cuprotosis regulatory subtype B in the genomics map and biological characteristics were significantly different from the other groups. Furthermore, these two subtypes had lower risk scores and longer survival times compared to other groups. Cox analyses indicated that risk score was an independent prognostic factor for AML patients. In addition, our risk score could be an indicator of survival outcomes in immunotherapy datasets.

CONCLUSIONS

Our study demonstrates the potential of CRGs in guiding the prognosis, treatment, and immunological characteristics of AML patients.

Real-world experience with CPX-351 in high-risk acute myeloid leukemia

CPX-351, a dual-drug liposomal encapsulation of daunorubicin/cytarabine, was approved for newly diagnosed therapy-related acute myeloid leukemia (AML) and AML with myelodysplasia-related changes in adults in 2017 (US; updated to patients aged ≥1 year in 2021) and 2018 (EU/UK) based on improved survival and remission and comparable safety versus 7+3 chemotherapy in a randomized trial in older adults. Real-world studies have since evaluated CPX-351 in routine practice across several countries and addressed important data gaps (e.g., use in younger adults, measurable residual disease negativity, outcomes by mutation). This review discusses real-world studies of CPX-351 as AML treatment, with the aim of helping prescribers make informed treatment decisions.

Activity of eftozanermin alfa plus venetoclax in preclinical models and patients with acute myeloid leukemia

Activation of apoptosis in malignant cells is an established strategy for controlling cancer and is potentially curative. To assess the impact of concurrently inducing the extrinsic and intrinsic apoptosis-signaling pathways in acute myeloid leukemia (AML), we evaluated activity of the TRAIL receptor agonistic fusion protein eftozanermin alfa (eftoza; ABBV-621) in combination with the B-cell lymphoma protein-2 selective inhibitor venetoclax in preclinical models and human patients. Simultaneously stimulating intrinsic and extrinsic apoptosis-signaling pathways with venetoclax and eftoza, respectively, enhanced their activities in AML cell lines and patient-derived ex vivo/in vivo models. Eftoza activity alone or plus venetoclax required death receptor 4/5 (DR4/DR5) expression on the plasma membrane but was independent of TP53 or FLT3-ITD status. The safety/tolerability of eftoza as monotherapy and in combination with venetoclax was demonstrated in patients with relapsed/refractory AML in a phase 1 clinical trial. Treatment-related adverse events were reported in 2 of 4 (50%) patients treated with eftoza monotherapy and 18 of 23 (78%) treated with eftoza plus venetoclax. An overall response rate of 30% (7/23; 4 complete responses [CRs], 2 CRs with incomplete hematologic recovery, and 1 morphologic leukemia-free state) was reported in patients who received treatment with eftoza plus venetoclax and 67% (4/6) in patients with myoblasts positive for DR4/DR5 expression; no tumor responses were observed with eftoza monotherapy. These data indicate that combination therapy with eftoza plus venetoclax to simultaneously activate the extrinsic and intrinsic apoptosis-signaling pathways may improve clinical benefit compared with venetoclax monotherapy in relapsed/refractory AML with an acceptable toxicity profile. This trial was registered at www.clinicaltrials.gov as #NCT03082209.

BCL-G: 20 years of research on a non-typical protein from the BCL-2 family

Proteins from the BCL-2 family control cell survival and apoptosis in health and disease, and regulate apoptosis-unrelated cellular processes. BCL-Gonad (BCL-G, also known as BCL2-like 14) is a non-typical protein of the family as its long isoform (BCL-G_L) consists of BH2 and BH3 domains without the BH1 motif. BCL-G is predominantly expressed in normal testes and different organs of the gastrointestinal tract. The complexity of regulatory mechanisms of BCL-G expression and post-translational modifications suggests that BCL-G may play distinct roles in different types of cells and disorders. While several genetic alterations of BCL2L14 have been reported, gene deletions and amplifications prevail, which is also confirmed by the analysis of sequencing data for different types of cancer. Although the studies validating the phenotypic consequences of genetic manipulations of BCL-G are limited, the role of BCL-G in apoptosis has been undermined. Recent studies using gene-perturbation approaches have revealed apoptosis-unrelated functions of BCL-G in intracellular trafficking, immunomodulation, and regulation of the mucin scaffolding network. These studies were, however, limited mainly to the role of BCL-G in the gastrointestinal tract. Therefore, further efforts using state-of-the-art methods and various types of cells are required to find out more about BCL-G activities. Deciphering the isoform-specific functions of BCL-G and the BCL-G interactome may result in the designing of novel therapeutic approaches, in which BCL-G activity will be either imitated using small-molecule BH3 mimetics or inhibited to counteract BCL-G upregulation. This review summarizes two decades of research on BCL-G.

Recent advances in targeted therapies in acute myeloid leukemia

Acute myeloid leukemia (AML) is the most common acute leukemia in adults. While survival for younger patients over the last several decades has improved nearly sixfold with the optimization of intensive induction chemotherapy and allogeneic stem cell transplantation (alloHSCT), this effect has been largely mitigated in older and less fit patients as well as those with adverse-risk disease characteristics. However, the last 10 years has been marked by major advances in the molecular profiling of AML characterized by a deeper understanding of disease pathobiology and therapeutic vulnerabilities. In this regard, the classification of AML subtypes has recently evolved from a morphologic to a molecular and genetic basis, reflected by recent updates from the World Health Organization and the new International Consensus Classification system. After years of stagnation in new drug approvals for AML, there has been a rapid expansion of the armamentarium against this disease since 2017. Low-intensity induction therapy with hypomethylating agents and venetoclax has substantially improved outcomes, including in those previously considered to have a poor prognosis. Furthermore, targeted oral therapies against driver mutations in AML have been added to the repertoire. But with an accelerated increase in treatment options, several questions arise such as how to best sequence therapy, how to combine therapies, and if there is a role for maintenance therapy in those who achieve remission and cannot undergo alloHSCT. Moreover, certain subtypes of AML, such as those with TP53 mutations, still have dismal outcomes despite these recent advances, underscoring an ongoing unmet need and opportunity for translational advances. In this review, we will discuss recent updates in the classification and risk stratification of AML, explore the literature regarding low-intensity and novel oral combination therapies, and briefly highlight investigative agents currently in early clinical development for high-risk disease subtypes.

A Successful Bridge Therapy Combining Hypomethylating Agents with Venetoclax for Adult Patients with Newly Diagnosed or Relapsed/Refractory Acute Myeloid Leukemia

Recently, the combination of VEN-HMA has been shown to achieve durable responses in patients with both newly diagnosed (ND) and R/R-AML. We retrospectively evaluated the post-allo-HCT outcomes of 50 patients who received VEN-HMA therapy. In total, 10 were ND and 40 were R/R and, at the time of HCT, the median age was 53 years. In the ND- and R/R-AML groups, the percentage of patients who achieved CR/CRi or MLFS was 90% and 92.5%, respectively. In all, after a median follow-up of 13.7 months, the probabilities of overall survival (OS), relapse-free survival (RFS), cumulative incidence of relapse (CIR), and nonrelapse mortality (NRM) at 1 year were 63.7%, 59.3%, 28.5%, and 12.2%, respectively. In addition, the cumulative incidences of grade II–IV acute graft-versus-host disease (GVHD) and moderate–severe chronic GVHD at 1 year were 28.4% and 37.4%, respectively. In multivariate analysis, the factors associated with a statistically significant impact on OS were VEN-HMA cycle (p = 0.021), ELN risk group (p = 0.041), and the response to VEN-HMA therapy before allo-HCT (p = 0.003). Although 80% of our patients had R/R-AML and 30% underwent a second allo-HCT, our data still suggest that allo-HCT following VEN-HMA therapy is a safe and effective treatment option.

Integrative phosphoproteomics defines two biologically distinct groups of KMT2A rearranged acute myeloid leukaemia with different drug response phenotypes

Acute myeloid leukaemia (AML) patients harbouring certain chromosome abnormalities have particularly adverse prognosis. For these patients, targeted therapies have not yet made a significant clinical impact. To understand the molecular landscape of poor prognosis AML we profiled 74 patients from two different centres (in UK and Finland) at the proteomic, phosphoproteomic and drug response phenotypic levels. These data were complemented with transcriptomics analysis for 39 cases. Data integration highlighted a phosphoproteomics signature that define two biologically distinct groups of KMT2A rearranged leukaemia, which we term MLLGA and MLLGB. MLLGA presented increased DOT1L phosphorylation, HOXA gene expression, CDK1 activity and phosphorylation of proteins involved in RNA metabolism, replication and DNA damage when compared to MLLGB and no KMT2A rearranged samples. MLLGA was particularly sensitive to 15 compounds including genotoxic drugs and inhibitors of mitotic kinases and inosine-5-monosphosphate dehydrogenase (IMPDH) relative to other cases. Intermediate-risk KMT2A-MLLT3 cases were mainly represented in a third group closer to MLLGA than to MLLGB. The expression of IMPDH2 and multiple nucleolar proteins was higher in MLLGA and correlated with the response to IMPDH inhibition in KMT2A rearranged leukaemia, suggesting a role of the nucleolar activity in sensitivity to treatment. In summary, our multilayer molecular profiling of AML with poor prognosis and KMT2A-MLLT3 karyotypes identified a phosphoproteomics signature that defines two biologically and phenotypically distinct groups of KMT2A rearranged leukaemia. These data provide a rationale for the potential development of specific therapies for AML patients characterised by the MLLGA phosphoproteomics signature identified in this study.

Current and Emerging Techniques for Diagnosis and MRD Detection in AML: A Comprehensive Narrative Review

Acute myeloid leukemia (AML) comprises a group of hematologic neoplasms characterized by abnormal differentiation and proliferation of myeloid progenitor cells. AML is associated with poor outcome due to the lack of efficient therapies and early diagnostic tools. The current gold standard diagnostic tools are based on bone marrow biopsy. These biopsies, apart from being very invasive, painful, and costly, have low sensitivity. Despite the progress uncovering the molecular pathogenesis of AML, the development of novel detection strategies is still poorly explored. This is particularly important for patients that check the criteria for complete remission after treatment, since they can relapse through the persistence of some leukemic stem cells. This condition, recently named as measurable residual disease (MRD), has severe consequences for disease progression. Hence, an early and accurate diagnosis of MRD would allow an appropriate therapy to be tailored, improving a patient's prognosis. Many novel techniques with high potential in disease prevention and early detection are being explored. Among them, microfluidics has flourished in recent years due to its ability at processing complex samples as well as its demonstrated capacity to isolate rare cells from biological fluids. In parallel, surface-enhanced Raman scattering (SERS) spectroscopy has shown outstanding sensitivity and capability for multiplex quantitative detection of disease biomarkers. Together, these technologies can allow early and cost-effective disease detection as well as contribute to monitoring the efficiency of treatments. In this review, we aim to provide a comprehensive overview of AML disease, the conventional techniques currently used for its diagnosis, classification (recently updated in September 2022), and treatment selection, and we also aim to present how novel technologies can be applied to improve the detection and monitoring of MRD.

Survival of TP53-mutated acute myeloid leukemia patients receiving allogeneic stem cell transplantation after first induction or salvage therapy: results from the Consortium on Myeloid Malignancies and Neoplastic Diseases (COMMAND)

We conducted a multi-center study to analyze factors predicting survival among patients with TP53-mutated (m) AML receiving allogeneic hematopoietic stem cell transplant (allo-HSCT) in the recent era. Out of 370 TP53m AML patients, 68 (18%) patients were bridged to allo-HSCT. The median age of the patients was 63 years (range, 33-75), 82% of patients had complex cytogenetics and 66% of patients had multi-hit TP53m. Forty three percent received myeloablative conditioning and 57% received reduced intensity conditioning. The incidence of acute graft versus host disease (GVHD) was 37% and chronic GVHD was 44%. The median event-free survival (EFS) from the time of allo-HSCT was 12.4 months (95% CI: 6.24-18.55) and median overall survival (OS) was 24.5 months (95% CI: 21.80-27.25). In multivariate analysis utilizing variables that showed significance in univariate analysis, complete remission at day 100 post allo-HSCT retained significance for EFS (HR: 0.24, 95% CI: 0.10-0.57, p = 0.001) and OS (HR: 0.22, 95% CI: 0.10-0.50, p ≤ 0.001). Similarly, occurrence of chronic GVHD retained significance for EFS (HR: 0.21, 95% CI: 0.09-0.46, p ≤ 0.001) and OS (HR: 0.34, 95% CI: 0.15-0.75, p = 0.007). Our report suggests that allo-HSCT offers the best opportunity to improve long-term outcome among patients with TP53m AML.

The Class IIA Histone Deacetylase (HDAC) Inhibitor TMP269 Downregulates Ribosomal Proteins and Has Anti-Proliferative and Pro-Apoptotic Effects on AML Cells

Acute myeloid leukemia (AML) is a hematopoietic malignancy characterized by altered myeloid progenitor cell proliferation and differentiation. As in many other cancers, epigenetic transcriptional repressors such as histone deacetylases (HDACs) are dysregulated in AML. Here, we investigated (1) HDAC gene expression in AML patients and in different AML cell lines and (2) the effect of treating AML cells with the specific class IIA HDAC inhibitor TMP269, by applying proteomic and comparative bioinformatic analyses. We also analyzed cell proliferation, apoptosis, and the cell-killing capacities of TMP269 in combination with venetoclax compared to azacitidine plus venetoclax, by flow cytometry. Our results demonstrate significantly overexpressed class I and class II HDAC genes in AML patients, a phenotype which is conserved in AML cell lines. In AML MOLM-13 cells, TMP269 treatment downregulated a set of ribosomal proteins which are overexpressed in AML patients at the transcriptional level. TMP269 showed anti-proliferative effects and induced additive apoptotic effects in combination with venetoclax. We conclude that TMP269 exerts anti-leukemic activity when combined with venetoclax and has potential as a therapeutic drug in AML.

The Cup Runneth Over: Treatment Strategies for Newly Diagnosed Acute Myeloid Leukemia

Since 2017, the number of agents for acute myeloid leukemia (AML) has rapidly expanded. Given the increased therapeutic options, better identification of high-risk subsets of AML and more refined approaches to patient fitness assessment, the decisions surrounding selection of intensive chemotherapy versus lower-intensity treatment have grown increasingly more nuanced. In this review, we present available data for both standard and investigational approaches in the initial treatment of AML using an intensive chemotherapy backbone or a lower-intensity approach. We summarize management strategies in newly diagnosed secondary AML, considerations around allogeneic stem-cell transplantation, and the role of maintenance therapy. Finally, we highlight important areas of future investigation and novel agents that may hold promise in combination with standard therapies.

Pyruvate Dehydrogenase Inhibition Leads to Decreased Glycolysis, Increased Reliance on Gluconeogenesis and Alternative Sources of Acetyl-CoA in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is an aggressive disease characterized by poor outcomes and therapy resistance. Devimistat is a novel agent that inhibits pyruvate dehydrogenase complex (PDH). A phase III clinical trial in AML patients combining devimistat and chemotherapy was terminated for futility, suggesting AML cells were able to circumvent the metabolic inhibition of devimistat. The means by which AML cells resist PDH inhibition is unknown. AML cell lines treated with devimistat or deleted for the essential PDH subunit, PDHA, showed a decrease in glycolysis and decreased glucose uptake due to a reduction of the glucose transporter GLUT1 and hexokinase II. Both devimistat-treated and PDHA knockout cells displayed increased sensitivity to 2-deoxyglucose, demonstrating reliance on residual glycolysis. The rate limiting gluconeogenic enzyme phosphoenolpyruvate carboxykinase 2 (PCK2) was significantly upregulated in devimistat-treated cells, and its inhibition increased sensitivity to devimistat. The gluconeogenic amino acids glutamine and asparagine protected AML cells from devimistat. Non-glycolytic sources of acetyl-CoA were also important with fatty acid oxidation, ATP citrate lyase (ACLY) and acyl-CoA synthetase short chain family member 2 (ACSS2) contributing to resistance. Finally, devimistat reduced fatty acid synthase (FASN) activity. Taken together, this suggests that AML cells compensate for PDH and glycolysis inhibition by gluconeogenesis for maintenance of essential glycolytic intermediates and fatty acid oxidation, ACLY and ACSS2 for non-glycolytic production of acetyl-CoA. Strategies to target these escape pathways should be explored in AML.

"Losing the Brakes"-Suppressed Inhibitors Triggering Uncontrolled Wnt/ß-Catenin Signaling May Provide a Potential Therapeutic Target in Elderly Acute Myeloid Leukemia

Dysregulated Wnt/β-catenin signal transduction is implicated in initiation, propagation, and poor prognosis in AML. Epigenetic inactivation is central to Wnt/β-catenin hyperactivity, and Wnt/β-catenin inhibitors are being investigated as targeted therapy. Dysregulated Wnt/β-catenin signaling has also been linked to accelerated aging. Since AML is a disease of old age (>60 yrs), we hypothesized age-related differential activity of Wnt/β-catenin signaling in AML patients. We probed Wnt/β-catenin expression in a series of AML in the elderly (>60 yrs) and compared it to a cohort of pediatric AML (<18 yrs). RNA from diagnostic bone marrow biopsies (n = 101) were evaluated for key Wnt/β-catenin molecule expression utilizing the NanoString platform. Differential expression of significance was defined as >2.5-fold difference (p < 0.01). A total of 36 pediatric AML (<18 yrs) and 36 elderly AML (>60 yrs) were identified in this cohort. Normal bone marrows (n = 10) were employed as controls. Wnt/β-catenin target genes (MYC, MYB, and RUNX1) showed upregulation, while Wnt/β-catenin inhibitors (CXXR, DKK1-4, SFRP1-4, SOST, and WIFI) were suppressed in elderly AML compared to pediatric AML and controls. Our data denote that suppressed inhibitor expression (through mutation or hypermethylation) is an additional contributing factor in Wnt/β-catenin hyperactivity in elderly AML, thus supporting Wnt/β-catenin inhibitors as potential targeted therapy.

Clinical Utility of Azacitidine in the Management of Acute Myeloid Leukemia: Update on Patient Selection and Reported Outcomes

Acute myeloid leukemia (AML) is predominantly a disease of the elderly, and a significant proportion of these patients are not candidates for intensive, curative-intent therapies. Epigenetic dysregulation resulting in abnormal DNA hypermethylation is one of the hallmarks of AML pathogenesis. For the past two decades, hypomethylating agents including azacitidine (AZA) have been the mainstay of treatment for AML patients who are ineligible to receive intensive chemotherapies. As our understanding of AML disease biology has improved, several novel treatment combinations have been developed to improve the outcome of AML patients, with remarkable success. A considerable proportion of these novel combinations have utilized AZA as the backbone of their treatment scheme. In this review, we have highlighted the evolution of AML treatment, focusing on novel AZA-based treatment combinations and their clinical efficacy.

Ex Vivo Drug Sensitivity Correlates with Clinical Response and Supports Personalized Therapy in Pediatric AML

Acute myeloid leukemia (AML) is a heterogeneous disease that accounts for ~20% of all childhood leukemias, and more than 40% of children with AML relapse within three years of diagnosis. Although recent efforts have focused on developing a precise medicine-based approach towards treating AML in adults, there remains a critical gap in therapies designed specifically for children. Here, we present ex vivo drug sensitivity profiles for children with de novo AML using an automated flow cytometry platform. Fresh diagnostic blood or bone marrow aspirate samples were screened for sensitivity in response to 78 dose conditions by measuring the reduction in leukemic blasts relative to the control. In pediatric patients treated with conventional chemotherapy, comprising cytarabine, daunorubicin and etoposide (ADE), ex vivo drug sensitivity results correlated with minimal residual disease (r = 0.63) and one year relapse-free survival (r = 0.70; AUROC = 0.94). In the de novo ADE analysis cohort of 13 patients, AML cells showed greater sensitivity to bortezomib/panobinostat compared with ADE, and comparable sensitivity between venetoclax/azacitidine and ADE ex vivo. Two patients showed a differential response between ADE and bortezomib/panobinostat, thus supporting the incorporation of ex vivo drug sensitivity testing in clinical trials to further evaluate the predictive utility of this platform in children with AML.

Targeting Apoptosis in AML: Where Do We Stand?

Simple Summary

In patients with acute myeloid leukemia (AML), genetic mutations can cause cells to evade regulated cell death (RCD), resulting in excessive cell proliferation. The best-known form of RCD is apoptosis, which prevents the emergence of cancer cells; disturbances in this process are an important factor in the development and progression of AML. Clearly, it is essential to understand the mechanisms of apoptosis to establish a personalized, patient-specific approach in AML therapy. Therefore, this paper comprehensively reviews the current range of AML treatment approaches related to apoptosis and highlights other promising concepts such as neddylation.

Abstract

More than 97% of patients with acute myeloid leukemia (AML) demonstrate genetic mutations leading to excessive proliferation combined with the evasion of regulated cell death (RCD). The most prominent and well-defined form of RCD is apoptosis, which serves as a defense mechanism against the emergence of cancer cells. Apoptosis is regulated in part by the BCL-2 family of pro- and anti-apoptotic proteins, whose balance can significantly determine cell survival. Apoptosis evasion plays a key role in tumorigenesis and drug resistance, and thus in the development and progression of AML. Research on the structural and biochemical aspects of apoptosis proteins and their regulators offers promise for new classes of targeted therapies and strategies for therapeutic intervention. This review provides a comprehensive overview of current AML treatment options related to the mechanism of apoptosis, particularly its mitochondrial pathway, and other promising concepts such as neddylation. It pays particular attention to clinically-relevant aspects of current and future AML treatment approaches, highlighting the molecular basis of individual therapies.

Induction Therapy and Survival for Acute Myeloid Leukemia in Hispanic Adults from Puerto Rico

BACKGROUND

Acute myeloid leukemia (AML) is the most common type of leukemia in adults. There are no previous studies evaluating AML treatment patterns in Puerto Rico. We describe the first-line therapy patterns and survival of patients diagnosed with AML in Puerto Rico using the Puerto Rico Central Cancer Registry Health Insurance Linkage Database (2011-2015).

METHODS

We describe patient characteristics according to intensive, non-intensive, and non-treatment status. We used Cox proportional hazard models to evaluate the factors associated with the risk of death stratified by intensive and non-intensive therapy. For this study, 385 patients with AML were included.

RESULTS

The mean age was 67 years old and 50.1% were female. Nearly half of AML patients (46.8%) received intensive treatment, 23.6% received non-intensive treatment, and 26.2% did not receive treatment. The overall 3-year survival rate was 17.9%. Among those who received intensive therapy, the risk of death among females was lower than males (hazard ratio [HR]: 0.64, 95% confidence interval [CI]: 0.44-0.93). Patients 60 years or older who received intensive treatment had a higher risk of death than younger patients (HR: 1.67, 95% CI: 1.09-2.55). Patients with poor/adverse risk receiving intensive (HR: 3.43, 95% CI: 1.76-6.69) or non-intensive (HR: 4.32, 95% CI: 1.66-11.28) treatment had a higher risk of death than patients with a favorable risk category.

CONCLUSION

Our findings are the first step to monitor the quality of care of patients with AML in Puerto Rico, particularly related to the administration of appropriate induction therapies, which is one of the most important predictors of AML survival.

Therapeutic targets and biomarkers of tumor immunotherapy: response versus non-response

Cancers are highly complex diseases that are characterized by not only the overgrowth of malignant cells but also an altered immune response. The inhibition and reprogramming of the immune system play critical roles in tumor initiation and progression. Immunotherapy aims to reactivate antitumor immune cells and overcome the immune escape mechanisms of tumors. Represented by immune checkpoint blockade and adoptive cell transfer, tumor immunotherapy has seen tremendous success in the clinic, with the capability to induce long-term regression of some tumors that are refractory to all other treatments. Among them, immune checkpoint blocking therapy, represented by PD-1/PD-L1 inhibitors (nivolumab) and CTLA-4 inhibitors (ipilimumab), has shown encouraging therapeutic effects in the treatment of various malignant tumors, such as non-small cell lung cancer (NSCLC) and melanoma. In addition, with the advent of CAR-T, CAR-M and other novel immunotherapy methods, immunotherapy has entered a new era. At present, evidence indicates that the combination of multiple immunotherapy methods may be one way to improve the therapeutic effect. However, the overall clinical response rate of tumor immunotherapy still needs improvement, which warrants the development of novel therapeutic designs as well as the discovery of biomarkers that can guide the prescription of these agents. Learning from the past success and failure of both clinical and basic research is critical for the rational design of studies in the future. In this article, we describe the efforts to manipulate the immune system against cancer and discuss different targets and cell types that can be exploited to promote the antitumor immune response.

A tubulin binding molecule drives differentiation of acute myeloid leukemia cells

Despite much progress in developing better drugs, many patients with acute myeloid leukemia (AML) still die within a year of diagnosis. This is partly because it is difficult to identify therapeutic targets that are effective across multiple AML subtypes. One common factor across AML subtypes is the presence of a block in differentiation. Overcoming this block should allow for the identification of therapies that are not dependent on a specific mutation for their efficacy. Here, we used a phenotypic screen to identify compounds that stimulate differentiation in genetically diverse AML cell lines. Lead compounds were shown to decrease tumor burden and to increase survival in vivo. Using multiple complementary target deconvolution approaches, these compounds were revealed to be anti-mitotic tubulin disruptors that cause differentiation by inducing a G2-M mitotic arrest. Together, these results reveal a function for tubulin disruptors in causing differentiation of AML cells.

In Pursuit of Genetic Prognostic Factors and Treatment Approaches in Secondary Acute Myeloid Leukemia—A Narrative Review of Current Knowledge

Secondary acute myeloid leukemia can be divided into two categories: AML evolving from the antecedent hematological condition (AHD-AML) and therapy related AML (t-AML). AHD-AML can evolve from hematological conditions such as myelodysplastic syndromes, myeloproliferative neoplasms, MDS/MPN overlap syndromes, Fanconi anemia, and aplastic anemia. Leukemic transformation occurs as a consequence of the clonal evolution—a process of the acquisition of mutations in clones, while previous mutations are also passed on, leading to somatic mutations accumulation. Compared de novo AML, secondary AML is generally associated with poorer response to chemotherapy and poorer prognosis. The therapeutic options for patients with s-AML have been confirmed to be limited, as s-AML has often been analyzed either both with de novo AML or completely excluded from clinical trials. The treatment of s-AML was not in any way different than de novo AML, until, that is, the introduction of CPX-351—liposomal daunorubicin and cytarabine. CPX-351 significantly improved the overall survival and progression free survival in elderly patients with s-AML. The only definitive treatment in s-AML at this time is allogeneic hematopoietic cell transplantation. A better understanding of the genetics and epigenetics of s-AML would allow us to determine precise biologic drivers leading to leukogenesis and thus help to apply a targeted treatment, improving prognosis.

Lymphocyte Exhaustion in AML Patients and Impacts of HMA/Venetoclax or Intensive Chemotherapy on Their Biology

Simple Summary

Patients with acute myeloid leukemia (AML) are routinely treated with either intensive chemotherapy or DNA hypomethylating agents (HMA) in combination with the Bcl-2 inhibitor, venetoclax. While both treatment regimens are highly cytotoxic to the aggressive AML tumor cells, they are also toxic to immune cells. Therefore, we sought to establish the detrimental impacts of these therapies on lymphocytes and their recovery over time in AML patients. Even prior to treatment initiation, the patients were found to have exhausted lymphocytes in peripheral blood, and additional signs of exhaustion were noted after treatment with HMA/venetoclax. In fact, the lymphocytes were still suppressed for two to three months after the initiation of induction therapy. Furthermore, T cells in a subset of patients subsequently found to be resistant to venetoclax therapy exhibited a higher expression of perforin and CD39 and more pronounced IFN-γ production.

Abstract

Acute myeloid leukemia (AML) is an aggressive malignancy that requires rapid treatment with chemotherapies to reduce tumor burden. However, these chemotherapies can compromise lymphocyte function, thereby hindering normal anti-tumor immune responses and likely limiting the efficacy of subsequent immunotherapy. To better understand these negative impacts, we assessed the immunological effects of standard-of-care AML therapies on lymphocyte phenotype and function over time. When compared to healthy donors, untreated AML patients showed evidence of lymphocyte activation and exhaustion and had more prevalent CD57⁺NKG2C⁺ adaptive NK cells, which was independent of human cytomegalovirus (HCMV) status. HMA/venetoclax treatment resulted in a greater fraction of T cells with effector memory phenotype, inhibited IFN-γ secretion by CD8⁺ T cells, upregulated perforin expression in NK cells, downregulated PD-1 and 2B4 expression on CD4⁺ T cells, and stimulated Treg proliferation and CTLA-4 expression. Additionally, we showed increased expression of perforin and CD39 and enhanced IFN-γ production by T cells from pre-treatment blood samples of venetoclax-resistant AML patients. Our results provide insight into the lymphocyte status in previously untreated AML patients and the effects of standard-of-care treatments on their biology and functions. We also found novel pre-treatment characteristics of T cells that could potentially predict venetoclax resistance.