Eprenetapopt Plus Azacitidine After Allogeneic Hematopoietic Stem-Cell Transplantation for TP53-Mutant Acute Myeloid Leukemia and Myelodysplastic Syndromes

The combined inhibition of SLC1A3 and glutaminase in osimertinib-resistant EGFR mutant cells

BACKGROUND

We investigated the unknown mechanisms of osimertinib-resistant EGFR-mutant lung cancer.

METHODS

An osimertinib-resistant cell line (PC-9/OsmR2) was established through continuous exposure to osimertinib using an EGFR exon 19 deletion (19Del) lung adenocarcinoma cell line (PC-9). EGFR 19Del (M1), L858R/T790M/C797S (M6), and L858R/C797S (M8) expression vectors were introduced into Ba/F3 cells. A second osimertinib-resistant line (M1/OsmR) was established through continuous exposure to osimertinib using M1 cells.

RESULTS

SLC1A3 had the highest mRNA expression level in PC-9/OsmR2 compared to PC-9 cells by microarray analysis and SLC1A3 was increased by flow cytometry. In PC-9/OsmR2 cells, osimertinib sensitivity was significantly increased in combination with siSLC1A3. Because SLC1A3 functions in glutamic acid transport, osimertinib with a glutaminase inhibitor (CB-839) or an SLC1A3 inhibitor (TFB-TBOA) increased the sensitivity. Also, CB-839 plus TFB-TBOA without osimertinib resulted in greater susceptibility than did CB-839 or TFB-TBOA plus osimertinib. Comprehensive metabolome analysis showed that the M1/OsmR cells had significantly more glutamine and glutamic acid than M1 cells. CB-839 plus osimertinib exerted a synergistic effect on M6 cells and an additive effect on M8 cells.

CONCLUSION

Targeting glutaminase and glutamic acid may overcome the osimertinib-resistant EGFR-mutant lung cancer.

SOHO State of the Art Updates and Next Questions: An Update on Higher Risk Myelodysplastic Syndromes

Higher-risk myelodysplastic syndromes (HR-MDS) are clonal myeloid neoplasms that cause life-limiting complications from severe cytopenias and leukemic transformation. Efforts to better classify, prognosticate, and assess therapeutic responses in HR-MDS have resulted in publication of new clinical tools in the last several years. Given limited current treatment options and suboptimal outcomes, HR-MDS stands to benefit from the study of investigational agents.Higher-risk myelodysplastic syndromes (HR-MDS) are a heterogenous group of clonal myeloid-lineage malignancies often characterized by high-risk genetic lesions, increased blood transfusion needs, constitutional symptoms, elevated risk of progression to acute myeloid leukemia (AML), and therapeutic need for allogeneic bone marrow transplantation. Use of blast percentage and other morphologic features to define myelodysplastic neoplasm subtypes is rapidly shifting to incorporate genetics, resulting in a subset of former HR-MDS patients now being considered as AML in presence of leukemia-defining genetic alterations. A proliferation of prognostic tools has further focused use of genetic features to drive decision making in clinical management. Recently, criteria to assess response of HR-MDS to therapy were revised to incorporate more clinically meaningful endpoints and better match AML response criteria. Basic science investigations have resulted in improved understanding of the relationship between MDS genetic lesions, bone marrow stromal changes, germline predispositions, and disease phenotype. However, therapeutic advances have been more limited. There has been import of the IDH1 inhibitor ivosidenib, initially approved for AML; the Bcl-2 inhibitor venetoclax and liposomal daunorubicin/cytarabine (CPX-351) are under active investigation as well. Unfortunately, effective treatment of TP53-mutated disease remains elusive, though preliminary evidence suggests improved outcomes with oral decitabine/cedazuridine over parenteral hypomethylating agent monotherapy. Investigational agents with novel mechanisms of action may help expand the repertoire of treatment options for HR-MDS and trials continue to offer a hopeful therapeutic avenue for suitable patients.

Evaluating targeted therapies in older patients with TP53-mutated AML

Mutation of thetumor suppressor gene, TP53 (tumor protein 53), occurs in up to 15% of all patients with acute myeloid leukemia (AML) and is enriched within specific clinical subsets, most notably in older adults, and including secondary AML cases arising from preceding myeloproliferative neoplasm (MPN), myelodysplastic syndrome (MDS), patients exposed to prior DNA-damaging, cytotoxic therapies. In all cases, these tumors have remained difficult to effectively treat with conventional therapeutic regimens. Newer approaches fortreatmentofTP53-mutated AML have shifted to interventions that maymodulateTP53 function, target downstream molecular vulnerabilities, target non-p53 dependent molecular pathways, and/or elicit immunogenic responses. This review will describe the basic biology of TP53, the clinical and biological patterns of TP53 within myeloid neoplasms with a focus on elderly AML patients and will summarize newer therapeutic strategies and current clinical trials.

Impact of p53-associated acute myeloid leukemia hallmarks on metabolism and the immune environment

Acute myeloid leukemia (AML), an aggressive malignancy of hematopoietic stem cells, is characterized by the blockade of cell differentiation, uncontrolled proliferation, and cell expansion that impairs healthy hematopoiesis and results in pancytopenia and susceptibility to infections. Several genetic and chromosomal aberrations play a role in AML and influence patient outcomes. TP53 is a key tumor suppressor gene involved in a variety of cell features, such as cell-cycle regulation, genome stability, proliferation, differentiation, stem-cell homeostasis, apoptosis, metabolism, senescence, and the repair of DNA damage in response to cellular stress. In AML, TP53 alterations occur in 5%-12% of de novo AML cases. These mutations form an important molecular subgroup, and patients with these mutations have the worst prognosis and shortest overall survival among patients with AML, even when treated with aggressive chemotherapy and allogeneic stem cell transplant. The frequency of TP53-mutations increases in relapsed and recurrent AML and is associated with chemoresistance. Progress in AML genetics and biology has brought the novel therapies, however, the clinical benefit of these agents for patients whose disease is driven by TP53 mutations remains largely unexplored. This review focuses on the molecular characteristics of TP53-mutated disease; the impact of TP53 on selected hallmarks of leukemia, particularly metabolic rewiring and immune evasion, the clinical importance of TP53 mutations; and the current progress in the development of preclinical and clinical therapeutic strategies to treat TP53-mutated disease.

Transplant versus no transplant in myelodysplastic syndrome and acute myeloid leukemia with TP53 mutation; a referral center experience

A remarkably high rate of post-transplant relapse in patients with TP53-mutated myelodysplastic syndrome/acute myeloid leukemia (MDS/AML) calls to question the utility of allogeneic stem cell transplant (HSCT). We, therefore, performed a retrospective analysis to compare the outcomes between HSCT (N = 38) versus non-HSCT (N = 45) approaches. Patients in the HSCT cohort were younger (median age 63 vs. 72) while patients in the non-HSCT cohort more commonly had complex karyotype with chromosome 17 aberrancy and 5q deletion (p < .01). A total of 69 TP53 variants including 64 pathogenic variants, and 5 variants of undetermined significance were detected. Nine patients (4 in HSCT and 5 in non-HSCT) had multi-hit TP53 variants. After induction: 57.9% versus 56.6% in the HSCT versus non-HSCT cohort achieved morphologic complete remission. Median time to HSCT was 6 months and median follow-up was 15.1 months for HSCT and 5.7 months for non-HSCT. Median disease-free survival (DFS) and overall survival (OS) were 11.7 and 15.9 months for HSCT, and 4.1 and 5.7 months for non-HSCT cohorts, respectively. Non-relapse mortality at 12 months was 22% versus 44% for HSCT versus non-HSCT. In the HSCT cohort, the rate of grade II-IV acute and chronic graft-versus-host disease (GVHD) was 55% and 18%, respectively. None of the patients from the non-HSCT cohort were alive while four patients from the HSCT cohort were alive, in remission, and without GVHD (GRFS) at the time of abstraction. Better treatment strategies for patients with TP53-mutated MDS/AML remain an area of unmet clinical need.

Molecular Subtypes and the Role of TP53 in Diffuse Large B-Cell Lymphoma and Richter Syndrome

Diffuse large B-cell lymphoma (DLBCL) is the most common lymphoid malignancy and a heterogeneous entity comprised of several biologically distinct subtypes. Recently, novel genetic classifications of DLBCL have been resolved based on common mutational patterns indicative of distinct pathways of transformation. However, the complicated and costly nature of the novel classifiers has precluded their inclusion into routine practice. In view of this, the status of the TP53 gene, which is mutated or deleted in 20-30% of the cases, has emerged as an important prognostic factor for DLBCL patients, setting itself apart from other predictors. TP53 genetic lesions are particularly enriched in a genetic subtype of DLBCL that shares genomic features with Richter Syndrome, highlighting the possibility of a subset of DLBCL arising from the transformation of an occult chronic lymphocytic leukemia-like malignancy, such as monoclonal B-cell lymphocytosis. Patients with TP53-mutated DLBCL, including those with Richter Syndrome, have a particularly poor prognosis and display inferior responses to standard chemoimmunotherapy regimens. The data presented in this manuscript argue for the need for improved and more practical risk-stratification models for patients with DLBCL and show the potential for the use of TP53 mutational status for prognostication and, in prospect, treatment stratification in DLBCL.

TP53 Mutations in Acute Leukemias and Myelodysplastic Syndromes: Insights and Treatment Updates

TP53 mutations are found in 5%-10% of de novo myelodysplastic syndrome (MDS) and AML cases. By contrast, in therapy related MDS and AML, mutations in TP53 are found in up to 30%-40% of patients. The majority of inactivating mutations observed in MDS and AML are missense mutations localized in a few prevalent hotspots. TP53 missense mutations together with truncating mutations or chromosomal loss of TP53 determine a loss-of-function effect on normal p53 function. Clonal expansion of TP53-mutant clones is observed under the selection pressure of chemotherapy or MDM2 inhibitor therapy. TP53-mutant clones are resistant to current chemotherapy, and when responses to treatment have been observed, they have correlated poorly with overall survival. The most heavily investigated and targeted agent for patients with TP53-mutant MDS and AML has been APR-246 (eprenetapopt) a p53 reactivator, in combination with azacitidine, but also in triplets with venetoclax. Despite positive results in phase II trials, a phase III trial did not confirm superior response or improved survival. Other agents, like magrolimab (anti-CD47 antibody), failed to demonstrate improved activity in TP53-mutant MDS and AML. Agents whose activity is not dependent on a functional apoptosis system like anti-CD123 antibodies or cellular therapies are in development and may hold promises. Delivering prognostic information in a dismal disease like TP53-mutated MDS and AML is particularly challenging. The physician should balance hope and realism, describing the trajectory of possible treatments and at the same time indicating the poor outcome, together with promoting adaptive coping in patients and elaborating on the nature of the disease.

Engineering the best transplant outcome for high-risk acute myeloid leukemia: the donor, the graft and beyond

Allogeneic hemopoietic cell transplantation remains the goal of therapy for high-risk acute myeloid leukemia (AML). However, treatment failure in the form of leukemia relapse or severe graft-versus-host disease remains a critical area of unmet need. Recently, significant progress has been made in the cell therapy-based interventions both before and after transplant. In this review, the Stem Cell Engineering Committee of the International Society for Cell and Gene Therapy summarizes the literature regarding the identification of high risk in AML, treatment approaches before transplant, optimal transplant platforms and measures that may be taken after transplant to ideally prevent, or, if need be, treat AML relapse. Although some strategies remain in the early phases of clinical investigation, they are built on progress in pre-clinical research and cellular engineering techniques that are already improving outcomes for children and adults with high-risk malignancies.

Post-Transplant Maintenance Therapy in Acute Myeloid Leukemia

Allogeneic hematopoietic cell transplantation (allo-HCT) is potentially curative for patients with acute myeloid leukemia (AML). However, the post-transplant relapse rate ranges from 40 to 70%, particularly with reduced intensity conditioning, and remains a major cause of treatment failure for these patients due to the limited efficacy of salvage therapy options. Strategies to mitigate this risk are urgently needed. In the past few years, the basic framework of post-transplant maintenance has been shaped by several clinical trials investigating targeted therapy, chemotherapy, and immunomodulatory therapies. Although the practice of post-transplant maintenance in AML has become more common, there remain challenges regarding the feasibility and efficacy of this strategy. Here, we review major developments in post-transplant maintenance in AML, along with ongoing and future planned studies in this area, outlining the limitations of available data and our future goals.

Therapy-Related Myeloid Neoplasm: Biology and Mechanistic Aspects of Malignant Progression

Therapy-related myeloid neoplasms (t-MN) arise after a documented history of chemo/radiotherapy as treatment for an unrelated condition and account for 10-20% of myelodysplastic syndromes and acute myeloid leukemia. T-MN are characterized by a specific genetic signature, aggressive features and dismal prognosis. The nomenclature and the subsets of these conditions have changed frequently over time, and despite the fact that, in the last classification, they lost their autonomous entity status and became disease qualifiers, the recognition of this feature remains of major importance. Furthermore, in recent years, extensive studies focusing on clonal hematopoiesis and germline variants shed light on the mechanisms of positive pressure underpinning the rise of driver gene mutations in t-MN. In this manuscript, we aim to review the evolution of defining criteria and characteristics of t-MN from a clinical and biological perspective, the advances in mechanistic aspects of malignant progression and the challenges in prevention and management.

TP53 in MDS and AML: Biological and clinical advances

Recently, the WHO-5 and the ICC 2022 criteria have emphasized poor prognosis in AML/MDS patients with multi-hit TP53 mutations, whereas mutated TP53 plays a critical role in tumorigenesis, drawing substantial interest in exploring its biological behaviors. Diverse characteristics of TP53 mutations, including types, VAF, CNVs, allelic status, karyotypes, and concurrent mutations have been extensively studied. Novel potential targets and comprehensive treatment strategies nowadays are under swift development, owing to great advances in technology. However, accurately predicting prognosis of patients with TP53-mutated myeloid neoplasms remains challenging. And there is still a lack of effective treatment for those patients.

Latest Insights and Therapeutic Advances in Myelodysplastic Neoplasms

Myelodysplastic syndromes/neoplasms (MDSs) encompass a range of hematopoietic malignancies, commonly affecting elderly individuals. Molecular alterations in the hematopoietic stem cell compartment drive disease pathogenesis. Recent advancements in genomic profiling have provided valuable insights into the biological underpinnings of MDSs and have expanded therapeutic options, particularly for specific molecularly defined subgroups. This review highlights the diagnostic principles, classification updates, prognostic stratification systems, and novel treatments, which could inform future clinical trials and enhance the management of adult MDS patients, particularly for specific molecularly defined subgroups.

Precision Medicine Approaches in Acute Myeloid Leukemia with Adverse Genetics

The treatment of acute myeloid leukemia (AML) with adverse genetics remains unsatisfactory, with very low response rates to standard chemotherapy and shorter durations of remission commonly observed in these patients. The complex biology of AML with adverse genetics is continuously evolving. Herein, we discuss recent advances in the field focusing on the contribution of molecular drivers of leukemia biogenesis and evolution and on the alterations of the immune system that can be exploited with immune-based therapeutic strategies. We focus on the biological rationales for combining targeted therapy and immunotherapy, which are currently being investigated in ongoing trials, and could hopefully ameliorate the poor outcomes of patients affected by AML with adverse genetics.

TP53-mutated acute myeloid leukemia and myelodysplastic syndrome: biology, treatment challenges, and upcoming approaches

Improved understanding of TP53 biology and the clinicopathological features of TP53-mutated myeloid neoplasms has led to the recognition of TP53-mutated acute myeloid leukemia/myelodysplastic syndrome (TP53m AML/MDS) as a unique entity, characterized by dismal outcomes following conventional therapies. Several clinical trials have investigated combinations of emerging therapies for these patients with the poorest molecular prognosis among myeloid neoplasms. Although some emerging therapies have shown improvement in overall response rates, this has not translated into better overall survival, hence the notion that p53 remains an elusive target. New therapeutic strategies, including novel targeted therapies, immune checkpoint inhibitors, and monoclonal antibodies, represent a shift away from cytotoxic and hypomethylating-based therapies, towards approaches combining non-immune and novel immune therapeutic strategies. The triple combination of azacitidine and venetoclax with either magrolimab or eprenetapopt have demonstrated safety in early trials, with phase III trials currently underway, and promising interim clinical results. This review compiles background on TP53 biology, available and emerging therapies along with their mechanisms of action for the TP53m disease entity, current treatment challenges, and recently published data and status of ongoing clinical trials for TP53m AML/MDS.

Outcomes with allogeneic hematopoietic stem cell transplantation in TP53-mutated myelodysplastic syndrome: A systematic review and meta-analysis

We conducted a systematic review and meta-analysis to evaluate outcomes after allogeneic hematopoietic stem cell transplantation (Allo-HSCT) in TP53-mutated myelodysplastic syndromes (MDS). A literature search was performed on PubMed, Cochrane, Embase, and Clinicaltrials.gov. After screening 626 articles, eight studies were included. Data were extracted following the PRISMA guidelines and analyzed using the meta-package by Schwarzer et al. We analyzed 540 patients. The pooled median 3 (1-5) year overall survival was 21% (95% CI 0.08-0.37, I2=91%, n=540). The pooled relapse rate was 58.9% (95% CI 0.38-0.77, I2=93%, n=487) at a median of 1.75 (1-3) years. The pooled 4-year progression- free survival was 34.8% (95% CI 0.15-0.57, I2=72%, n=105). Outcomes of Allo-HSCT for TP53-mutated MDS patients remain poor, with 21% OS at three years; however, Allo-HSCT confers a survival advantage as compared to non-transplant palliative therapies. Our findings suggest the need to explore novel therapeutic agents in prospective clinical trials.

Innovations in conditioning and post-transplant maintenance in AML: genomically informed revelations on the graft-versus-leukemia effect

Acute Myeloid Leukemia (AML) is the prototype of cancer genomics as it was the first published cancer genome. Large-scale next generation/massively parallel sequencing efforts have identified recurrent alterations that inform prognosis and have guided the development of targeted therapies. Despite changes in the frontline and relapsed standard of care stemming from the success of small molecules targeting FLT3, IDH1/2, and apoptotic pathways, allogeneic stem cell transplantation (alloHSCT) and the resulting graft-versus-leukemia (GVL) effect remains the only curative path for most patients. Advances in conditioning regimens, graft-vs-host disease prophylaxis, anti-infective agents, and supportive care have made this modality feasible, reducing transplant related mortality even among patients with advanced age or medical comorbidities. As such, relapse has emerged now as the most common cause of transplant failure. Relapse may occur after alloHSCT because residual disease clones persist after transplant, and develop immune escape from GVL, or such clones may proliferate rapidly early after alloHSCT, and outpace donor immune reconstitution, leading to relapse before any GVL effect could set in. To address this issue, genomically informed therapies are increasingly being incorporated into pre-transplant conditioning, or as post-transplant maintenance or pre-emptive therapy in the setting of mixed/falling donor chimerism or persistent detectable measurable residual disease (MRD). There is an urgent need to better understand how these emerging therapies modulate the two sides of the GVHD vs. GVL coin: 1) how molecularly or immunologically targeted therapies affect engraftment, GVHD potential, and function of the donor graft and 2) how these therapies affect the immunogenicity and sensitivity of leukemic clones to the GVL effect. By maximizing the synergistic action of molecularly targeted agents, immunomodulating agents, conventional chemotherapy, and the GVL effect, there is hope for improving outcomes for patients with this often-devastating disease.

Translating p53-based therapies for cancer into the clinic

Inactivation of the most important tumour suppressor gene TP53 occurs in most, if not all, human cancers. Loss of functional wild-type p53 is achieved via two main mechanisms: mutation of the gene leading to an absence of tumour suppressor activity and, in some cases, gain-of-oncogenic function; or inhibition of the wild-type p53 protein mediated by overexpression of its negative regulators MDM2 and MDMX. Because of its high potency as a tumour suppressor and the dependence of at least some established tumours on its inactivation, p53 appears to be a highly attractive target for the development of new anticancer drugs. However, p53 is a transcription factor and therefore has long been considered undruggable. Nevertheless, several innovative strategies have been pursued for targeting dysfunctional p53 for cancer treatment. In mutant p53-expressing tumours, the predominant strategy is to restore tumour suppressor function with compounds acting either in a generic manner or otherwise selective for one or a few specific p53 mutations. In addition, approaches to deplete mutant p53 or to target vulnerabilities created by mutant p53 expression are currently under development. In wild-type p53 tumours, the major approach is to protect p53 from the actions of MDM2 and MDMX by targeting these negative regulators with inhibitors. Although the results of at least some clinical trials of MDM2 inhibitors and mutant p53-restoring compounds are promising, none of the agents has yet been approved by the FDA. Alternative strategies, based on a better understanding of p53 biology, the mechanisms of action of compounds and treatment regimens as well as the development of new technologies are gaining interest, such as proteolysis-targeting chimeras for MDM2 degradation. Other approaches are taking advantage of the progress made in immune-based therapies for cancer. In this Review, we present these ongoing clinical trials and emerging approaches to re-evaluate the current state of knowledge of p53-based therapies for cancer.

New treatment opportunities for older patients with acute myeloid leukemia and the increasing importance of frailty assessment - An oncogeriatric perspective

With the introduction of targeted chemotherapy drugs, a new age of treatment for acute myeloid leukemia (AML) has begun. The promotion of the azacitidine+venetoclax combination regimen to first line of treatment in patients deemed ineligible for intensive chemotherapy marks the first of many novel combination regimens becoming part of national treatment guidelines. We review recent phase II and III clinical trials and conclude that these novel regimens offer significant increases in response rates, remission rates, and overall survival. The incidence of adverse events, the accrued time toxicity, and the healthcare costs, however, are increasing as well. Compared with clinical trials, older patients in the real world frequently present with an inferior baseline health status, which is associated with an increased risk of experiencing side effects. The key to reaping the maximum benefit of the new agents and their combination regimens therefore lies in sufficient attention being given to a patients' preexisting comorbidities, potential frailty, and quality of life. A systematic collaboration between hemato-oncologists and geriatricians can be a potent first step towards addressing the increased treatment intensity patients with AML experience under the novel regimens. In this narrative review article we provide an overview of recent and ongoing clinical trials, highlight encountered adverse events, discuss frailty assessment options, and outline an oncogeriatic care path for older patients with AML.

Cell fate regulation governed by p53: Friends or reversible foes in cancer therapy

Cancer is a leading cause of death worldwide. Targeted therapies aimed at key oncogenic driver mutations in combination with chemotherapy and radiotherapy as well as immunotherapy have benefited cancer patients considerably. Tumor protein p53 (TP53), a crucial tumor suppressor gene encoding p53, regulates numerous downstream genes and cellular phenotypes in response to various stressors. The affected genes are involved in diverse processes, including cell cycle arrest, DNA repair, cellular senescence, metabolic homeostasis, apoptosis, and autophagy. However, accumulating recent studies have continued to reveal novel and unexpected functions of p53 in governing the fate of tumors, for example, functions in ferroptosis, immunity, the tumor microenvironment and microbiome metabolism. Among the possibilities, the evolutionary plasticity of p53 is the most controversial, partially due to the dizzying array of biological functions that have been attributed to different regulatory mechanisms of p53 signaling. Nearly 40 years after its discovery, this key tumor suppressor remains somewhat enigmatic. The intricate and diverse functions of p53 in regulating cell fate during cancer treatment are only the tip of the iceberg with respect to its equally complicated structural biology, which has been painstakingly revealed. Additionally, TP53 mutation is one of the most significant genetic alterations in cancer, contributing to rapid cancer cell growth and tumor progression. Here, we summarized recent advances that implicate altered p53 in modulating the response to various cancer therapies, including chemotherapy, radiotherapy, and immunotherapy. Furthermore, we also discussed potential strategies for targeting p53 as a therapeutic option for cancer.

Unmet Horizons: Assessing the Challenges in the Treatment of TP53-Mutated Acute Myeloid Leukemia

Acute myeloid leukemia (AML) remains a challenging hematologic malignancy. The presence of TP53 mutations in AML poses a therapeutic challenge, considering that standard treatments face significant setbacks in achieving meaningful responses. There is a pressing need for the development of innovative treatment modalities to overcome resistance to conventional treatments attributable to the unique biology of TP53-mutated (TP53mut) AML. This review underscores the role of TP53 mutations in AML, examines the current landscape of treatment options, and highlights novel therapeutic approaches, including targeted therapies, combination regimens, and emerging immunotherapies, as well as agents being explored in preclinical studies according to their potential to address the unique hurdles posed by TP53mut AML.

Utility or futility? A contemporary approach to allogeneic hematopoietic cell transplantation for TP53-mutated MDS/AML

ABSTRACT

TP 53-mutated myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) are among the most lethal malignancies, characterized by dismal outcomes with currently available therapies. Allogeneic hematopoietic cell transplantation (allo-HCT) is widely thought to be the only treatment option to offer durable disease control. However, outcomes with allo-HCT in this context are quite poor, calling into question the utility of transplantation. In this review, we summarize the latest data on allo-HCT outcomes in this subgroup, evaluating the limitations of available evidence; we review the molecular heterogeneity of this disease, delineating outcomes based on distinct biological features to aid in patient selection; and we critically examine whether allo-HCT should be routinely applied in this disease on the basis of currently available data. We propose that the exceptionally poor outcomes of patients with TP53-mutated MDS/AML with biallelic loss and/or adverse-risk cytogenetics should motivate randomized-controlled trials of HCT vs non-HCT to determine whether transplantation can prolong survival and/or positively impact other clinically relevant outcomes such as patient-reported outcomes or healthcare resource utilization in this disease subset. Without dedicated prospective randomized trials, selecting who may actually derive benefit from allo-HCT for TP53-mutated MDS/AML can be described as ambiguous guesswork and must be carefully contemplated.

Pharmacological reactivation of p53 in the era of precision anticancer medicine

p53, which is encoded by the most frequently mutated gene in cancer, TP53, is an attractive target for novel cancer therapies. Despite major challenges associated with this approach, several compounds that either augment the activity of wild-type p53 or restore all, or some, of the wild-type functions to p53 mutants are currently being explored. In wild-type TP53 cancer cells, p53 function is often abrogated by overexpression of the negative regulator MDM2, and agents that disrupt p53-MDM2 binding can trigger a robust p53 response, albeit potentially with induction of p53 activity in non-malignant cells. In TP53-mutant cancer cells, compounds that promote the refolding of missense mutant p53 or the translational readthrough of nonsense mutant TP53 might elicit potent cell death. Some of these compounds have been, or are being, tested in clinical trials involving patients with various types of cancer. Nonetheless, no p53-targeting drug has so far been approved for clinical use. Advances in our understanding of p53 biology provide some clues as to the underlying reasons for the variable clinical activity of p53-restoring therapies seen thus far. In this Review, we discuss the intricate interactions between p53 and its cellular and microenvironmental contexts and factors that can influence p53's activity. We also propose several strategies for improving the clinical efficacy of these agents through the complex perspective of p53 functionality.

Potential applications of ferroptosis inducers and regulatory molecules in hematological malignancy therapy

Ferroptosis, a novel form of iron-dependent cell death, has emerged as a potential avenue for promoting tumor cell death by causing cell membrane rupture and the accumulation of lipid peroxides (LPO) in the cell. Since its discovery in 2012, extensive research has been conducted to explore the mechanism of ferroptosis inducers, including erastin, sulfasalazine, and sorafenib. These compounds inhibit system XC-, while Ras-selective lethal small molecule 3 (RSL3) and FION2 specifically target GPX4 to promote ferroptosis. Therefore, targeting ferroptosis presents a promising therapeutic approach for malignant tumors. While the study of ferroptosis in solid tumors has made significant progress, there is limited information available on its role in hematological tumors. This review aims to summarize the molecular mechanisms of ferroptosis inducers and discuss their clinical applications in hematological malignancies. Furthermore, the identification of non-coding RNAs (ncRNAs) and genes that regulate key molecules in the ferroptosis pathway could provide new targets and establish a molecular theoretical foundation for exploring novel ferroptosis inducers in hematological malignancies.

Clinical decision-making and treatment of myelodysplastic syndromes

ABSTRACT

The myelodysplastic syndromes (MDSs) constitute a profoundly heterogeneous myeloid malignancy with a common origin in the hemopoietic stem cell compartment. Consequently, patient management and treatment are as heterogeneous. Decision-making includes identifying risk, symptoms, and options for an individual and conducting a risk-benefit analysis. The only potential cure is allogeneic stem cell transplantation, and albeit the fraction of patients with MDS who undergo transplant increase over time because of better management and increased donor availability, a majority are not eligible for this intervention. Current challenges encompass to decrease the relapse risk, the main cause of hematopoietic stem cell transplantation failure. Hypomethylating agents (HMAs) constitute firstline treatment for higher-risk MDSs. Combinations with other drugs as firstline treatment has, to date, not proven more efficacious than monotherapy, although combinations approved for acute myeloid leukemia, including venetoclax, are under evaluation and often used as rescue treatment. The treatment goal for lower-risk MDS is to improve cytopenia, mainly anemia, quality of life, and, possibly, overall survival. Erythropoiesis-stimulating agents (ESAs) constitute firstline treatment for anemia and have better and more durable responses if initiated before the onset of a permanent transfusion need. Treatment in case of ESA failure or ineligibility should be tailored to the main disease mechanism: immunosuppression for hypoplastic MDS without high-risk genetics, lenalidomide for low-risk del(5q) MDS, and luspatercept for MDS with ring sideroblasts. Approved therapeutic options are still scarcer for MDS than for most other hematologic malignancies. Better tools to match disease biology with treatment, that is, applied precision medicines are needed to improve patient outcome.

Tolerability and Efficacy of the Anticluster of Differentiation 47 Antibody Magrolimab Combined With Azacitidine in Patients With Previously Untreated AML: Phase Ib Results

PURPOSE

Magrolimab is a first-in-class humanized monoclonal antibody against cluster of differentiation 47, an antiphagocytic signal used by cancer cells to evade phagocytosis. Azacitidine upregulates prophagocytic signals on AML cells, further increasing phagocytosis when combined with magrolimab. We report final phase Ib data for magrolimab with azacitidine in patients with untreated AML ineligible for intensive chemotherapy (ClinicalTrials.gov identifier: NCT03248479).

PATIENTS AND METHODS

Patients with previously untreated AML, including TP53-mutant AML, received magrolimab intravenously as an initial dose (1 mg/kg, days 1 and 4), followed by 15 mg/kg once on day 8 and 30 mg/kg once weekly or every 2 weeks as maintenance. Azacitidine 75 mg/m2 was administered intravenously/subcutaneously once daily on days 1-7 of each 28-day cycle. Primary end points were safety/tolerability and proportion with complete remission (CR).

RESULTS

Eighty-seven patients were enrolled and treated; 72 (82.8%) had TP53 mutations with a median variant allele frequency of 61% (range, 9.8-98.7). Fifty-seven (79.2%) of TP53-mutant patients had European LeukemiaNet 2017 adverse-risk cytogenetics. Patients received a median of 4 (range, 1-39) cycles of treatment. The most common treatment-emergent adverse events included constipation (49.4%), nausea (49.4%), and diarrhea (48.3%). Thirty (34.5%) experienced anemia, and the median hemoglobin change from baseline to first postdose assessment was -0.9 g/dL (range, -3.6 to 2.5 g/dL). Twenty-eight (32.2%) patients achieved CR, including 23 (31.9%) patients with TP53 mutations. The median overall survival in TP53-mutant and wild-type patients were 9.8 months and 18.9 months, respectively.

CONCLUSION

Magrolimab with azacitidine was relatively well tolerated with promising efficacy in patients with AML ineligible for intensive induction chemotherapy, including those with TP53 mutations, warranting further evaluation of magrolimab with azacitidine in AML. The phase III randomized ENHANCE-2 (ClinicalTrials.gov identifier: NCT04778397) and ENHANCE-3 (ClinicalTrials.gov identifier: NCT05079230) studies are recruiting frontline patients with AML.

Recent advances in precision medicine for acute myeloid leukemia

PURPOSE OF REVIEW

Acute myeloid leukemia (AML) is a heterogeneous disease, in which treatment response and patient survival are highly conditioned by the leukemia biology. The aim of this review is to summarize recent advances in AML classification, risk stratification models, measurable residual disease (MRD) and the increasing number of treatment options that are paving the way towards precision medicine in AML.

RECENT FINDINGS

AML classification and risk stratification were recently updated by incorporating novel molecular markers that are important for diagnosis and outcome prediction. In addition, the impact of co-mutational patterns is under investigation and novel approaches using machine learning algorithms are starting to be used for individualized risk estimation. Molecular markers are also becoming useful in predicting response to non-intensive treatments. MRD informs of treatment response with high sensitivity, allowing dynamic patient risk assessment and early intervention. Finally, important advances were made in AML therapy, with an increasing number of targeted therapies becoming available and many novel treatment approaches being under development with promising early results.

SUMMARY

A better understanding of AML biology is leading to improved risk stratification and important advances in treatments, which are allowing the development of precision medicine in AML at an unprecedented pace.

Prognostic heterogeneity and clonal dynamics within distinct subgroups of myelodysplastic syndrome and acute myeloid leukemia with TP53 disruptions

TP53 aberrations constitute the highest risk subset of myelodysplastic neoplasms (MDS) and acute myeloid leukemia (AML). The International Consensus Classification questions the blast threshold between MDS and AML. In this study, we assess the distinction between MDS and AML for 76 patients with TP53 aberrations. We observed no significant differences between MDS and AML regarding TP53 genomics. Median overall survival (OS) was 223 days for the entire group, but prognostic discrimination within subgroups showed the most inferior OS (46 days) for AML with multihit allelic state plus TP53 variant allele frequency (VAF) > 50%. In multivariate analysis, unadjusted Cox models revealed the following variables as independent risk factors for mortality: AML (vs. MDS) (hazard ratio [HR]: 2.50, confidence interval [CI]: 1.4-4.4, p = 0.001), complex karyotype (HR: 3.00, CI: 1.4-6.1, p = 0.003), multihit status (HR: 2.30, CI 1.3-4.2, p = 0.005), and absence of hematopoietic cell transplant (HCT) (HR: 3.90, CI: 1.8-8.9, p = 0.0009). Clonal dynamic modeling showed a significant reduction in TP53 VAF with front-line hypomethylating agents. These findings clarify the impact of specific covariates on outcomes of TP53-aberrant myeloid neoplasms, irrespective of the diagnosis of MDS versus AML, and may influence HCT decisions.

Targeting apoptosis dysregulation in myeloid malignancies - The promise of a therapeutic revolution

In recent years, the therapeutic landscape of myeloid malignancies has been completely revolutionized by the introduction of several new drugs, targeting molecular alterations or pathways crucial for leukemia cells survival. Particularly, many agents targeting apoptosis have been investigated in both pre-clinical and clinical studies. For instance, venetoclax, a pro-apoptotic agent active on BCL-2 signaling, has been successfully used in the treatment of acute myeloid leukemia (AML). The impressive results achieved in this context have made the apoptotic pathway an attractive target also in other myeloid neoplasms, translating the experience of AML. Therefore, several drugs are now under investigation either as single or in combination strategies, due to their synergistic efficacy and capacity to overcome resistance. In this paper, we will review the mechanisms of apoptosis and the specific drugs currently used and under investigation for the treatment of myeloid neoplasia, identifying critical research necessities for the upcoming years.

Allogeneic Hematopoietic Cell Transplantation Improves Outcome in Myelodysplastic Syndrome Across High-Risk Genetic Subgroups: Genetic Analysis of the Blood and Marrow Transplant Clinical Trials Network 1102 Study

PURPOSE

Allogeneic hematopoietic cell transplantation (HCT) in patients with myelodysplastic syndrome (MDS) improves overall survival (OS). We evaluated the impact of MDS genetics on the benefit of HCT in a biological assignment (donor v no donor) study.

METHODS

We performed targeted sequencing in 309 patients age 50-75 years with International Prognostic Scoring System (IPSS) intermediate-2 or high-risk MDS, enrolled in the Blood and Marrow Transplant Clinical Trials Network 1102 study and assessed the association of gene mutations with OS. Patients with TP53 mutations were classified as TP53multihit if two alleles were altered (via point mutation, deletion, or copy-neutral loss of heterozygosity).

RESULTS

The distribution of gene mutations was similar in the donor and no donor arms, with TP53 (28% v 29%; P = .89), ASXL1 (23% v 29%; P = .37), and SRSF2 (16% v 16%; P = .99) being most common. OS in patients with a TP53 mutation was worse compared with patients without TP53 mutation (21% ± 5% [SE] v 52% ± 4% at 3 years; P < .001). Among those with a TP53 mutation, OS was similar between TP53single versus TP53multihit (22% ± 8% v 20% ± 6% at 3 years; P = .31). Considering HCT as a time-dependent covariate, patients with a TP53 mutation who underwent HCT had improved OS compared with non-HCT treatment (OS at 3 years: 23% ± 7% v 11% ± 7%; P = .04), associated with a hazard ratio of 3.89; 95% CI, 1.87 to 8.12; P < .001 after adjustment for covariates. OS among patients with molecular IPSS (IPSS-M) very high risk without a TP53 mutation was significantly improved if they had a donor (68% ± 10% v 0% ± 12% at 3 years; P = .001).

CONCLUSION

HCT improved OS compared with non-HCT treatment in patients with TP53 mutations irrespective of TP53 allelic status. Patients with IPSS-M very high risk without a TP53 mutation had favorable outcomes when a donor was available.

TP53 Mutation in Acute Myeloid Leukemia: An Old Foe Revisited

INTRODUCTION

TP53 is the most commonly mutated gene in human cancers and was the first tumor suppressor gene to be discovered in the history of medical science. Mutations in the TP53 gene occur at various genetic locations and exhibit significant heterogeneity among patients. Mutations occurring primarily within the DNA-binding domain of TP53 result in the loss of the p53 protein's DNA-binding capability. However, a complex phenotypic landscape often combines gain-of-function, dominant negative, or altered specificity features. This complexity poses a significant challenge in developing an effective treatment strategy, which eradicates TP53-mutated cancer clones. This review summarizes the current understanding of TP53 mutations in AML and their implications. TP53 mutation in AML: In patients with acute myeloid leukemia (AML), six hotspot mutations (R175H, G245S, R248Q/W, R249S, R273H/S, and R282W) within the DNA-binding domain are common. TP53 mutations are frequently associated with a complex karyotype and subgroups of therapy-related or secondary AML. The presence of TP53 mutation is considered as a poor prognostic factor. TP53-mutated AML is even classified as a distinct subgroup of AML by itself, as TP53-mutated AML exhibits a significantly distinct landscape in terms of co-mutation and gene expression profiles compared with wildtype (WT)-TP53 AML.

CLINICAL IMPLICATIONS

To better predict the prognosis in cancer patients with different TP53 mutations, several predictive scoring systems have been proposed based on screening experiments, to assess the aggressiveness of TP53-mutated cancer cells. Among those scoring systems, a relative fitness score (RFS) could be applied to AML patients with TP53 mutations in terms of overall survival (OS) and event-free survival (EFS). The current standard treatment, which includes cytotoxic chemotherapy and allogeneic hematopoietic stem cell transplantation, is largely ineffective for patients with TP53-mutated AML. Consequently, most patients with TP53-mutated AML succumb to leukemia within several months, despite active anticancer treatment. Decitabine, a hypomethylating agent, is known to be relatively effective in patients with AML. Numerous trials are ongoing to investigate the effects of novel drugs combined with hypomethylating agents, TP53-targeting agents or immunologic agents.

CONCLUSIONS

Developing an effective treatment strategy for TP53-mutated AML through innovative and multidisciplinary research is an urgent task. Directly targeting mutated TP53 holds promise as an approach to combating TP53-mutated AML, and recent developments in immunologic agents for AML offer hope in this field.

Susceptibility of acute myeloid leukemia cells to ferroptosis and evasion strategies

Acute myeloid leukemia (AML) is a highly aggressive hematologic malignancy with a 5-year survival rate of less than 30%. Continuous updating of diagnostic and therapeutic strategies has not been effective in improving the clinical benefit of AML. AML cells are prone to iron metabolism imbalance due to their unique pathological characteristics, and ferroptosis is a novel cell death mode that is dominated by three cellular biological processes: iron metabolism, oxidative stress and lipid metabolism. An in-depth exploration of the unique ferroptosis mechanism in AML can provide new insights for the diagnosis and treatment of this disease. This study summarizes recent studies on ferroptosis in AML cells and suggests that the metabolic characteristics, gene mutation patterns, and dependence on mitochondria of AML cells greatly increase their susceptibility to ferroptosis. In addition, this study suggests that AML cells can establish a variety of strategies to evade ferroptosis to maintain their survival during the process of occurrence and development, and summarizes the related drugs targeting ferroptosis pathway in AML treatment, which provides development directions for the subsequent mechanism research and clinical treatment of AML.

Mechanisms of Resistance to Small Molecules in Acute Myeloid Leukemia

In recent years, great progress has been made in the therapy of AML by targeting cellular processes associated with specific molecular features of the disease. Various small molecules inhibiting FLT3, IDH1/IDH2, and BCL2 have already gained approval from the respective authorities and are essential parts of personalized therapeutic regimens in modern therapy of AML. Unfortunately, primary and secondary resistance to these inhibitors is a frequent problem. Here, we comprehensively review the current state of knowledge regarding molecular processes involved in primary and secondary resistance to these agents, covering both genetic and nongenetic mechanisms. In addition, we introduce concepts and strategies for how these resistance mechanisms might be overcome.

Precision and strategic targeting of novel mutation-specific vulnerabilities in acute myeloid leukemia: the semi-centennial of 7 + 3

The year 2023 marks the semi-centennial of the introduction of classic '7 + 3' chemotherapy for acute myeloid leukemia (AML) in 1973. It also marks the decennial of the first comprehensive sequencing efforts from The Cancer Genome Atlas (TCGA), which revealed that dozens of unique genes are recurrently mutated in AML genomes. Although more than 30 distinct genes have been implicated in AML pathogenesis, the current therapeutic armamentarium that is commercially available only targets FLT3 and IDH1/2 mutations, with olutasidenib as the most recent addition. This focused review spotlights management approaches that exploit the exquisite molecular dependencies of specific subsets of AML, with an emphasis on emerging therapies in the pipeline, including agents targeting TP53-mutant cells. We summarize precision and strategic targeting of AML based on leveraging functional dependencies and explore how mechanisms involving critical gene products can inform rational therapeutic design in 2024.

Venetoclax is safe and tolerable as post-transplant maintenance therapy for AML patients at high risk for relapse

Relapse is the most common cause of mortality in acute myeloid leukemia (AML) patients after allogeneic stem cell transplant (SCT). Post-SCT maintenance strategies that prevent relapse are desirable but must be well tolerated and convenient to administer. We hypothesized single agent venetoclax (ven) may be an effective maintenance therapy among high relapse risk patients. Between February 2019 and December 2021, we administered post-SCT ven maintenance to 49 AML patients at high-risk for relapse as a prospectively defined off-label practice at our institution. Ven was planned to be administered until 1-year post-SCT. While temporary interruptions were common (67.3% of all patients), of those with >1 year follow up, 22/25 (88%) completed the full year of planned therapy. Cytopenias (40.8%) and gastrointestinal adverse events (34.7%) were the most common toxicities. At 1-year post-SCT, overall survival (OS) and relapse-free survival (RFS) were 70% and 67% respectively. Our experience demonstrates single agent ven is a safe, tolerable, and feasible maintenance therapy that may improve RFS and OS in high relapse risk post-SCT patients.

Update on Small Molecule Targeted Therapies for Acute Myeloid Leukemia

OPINION STATEMENT

The search for effective therapies for the highly heterogenous disease acute myeloid leukemia (AML) has remained elusive. While cytotoxic therapies can induce complete remission and even, at times, long-term survival, this approach is associated with significant toxic effects to visceral organs and worsening of immune dysfunction and marrow suppression leading to death. Sophisticated molecular studies have revealed defects within the AML cell that can be exploited by utilizing small molecule agents to target these defects, often dubbed "target therapy." Several medications have already established new standards of care for many patients with AML, including FDA-approved agents that inhibitor IDH1, IDH2, FLT3, and BCL-2. Emerging small molecules hold additional to add to the armamentarium of AML treatment options including MCL-1 inhibitors, TP53 inhibitors, menin inhibitors, and E-selectin antagonists. Moreover, the increasing options also mean that future combinations of these agents need to be explored, including with cytotoxic drugs and other newer emerging strategies such as immunotherapies for AML. Recent investigations continue to show that overcoming many of the challenges of treating AML finally is on the horizon.

TP53-Mutated Myelodysplasia and Acute Myeloid Leukemia

TP53-mutated myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) form a distinct and heterogeneous group of myeloid malignancies associated with poor outcomes. Studies carried out in the last years have in part elucidated the complex role played by TP53 mutations in the pathogenesis of these myeloid disorders and in the mechanisms of drug resistance. A consistent number of studies has shown that some molecular parameters, such as the presence of a single or multiple TP53 mutations, the presence of concomitant TP53 deletions, the association with co-occurring mutations, the clonal size of TP53 mutations, the involvement of a single (monoallelic) or of both TP53 alleles (biallelic) and the cytogenetic architecture of concomitant chromosome abnormalities are major determinants of outcomes of patients. The limited response of these patients to standard treatments, including induction chemotherapy, hypomethylating agents and venetoclax-based therapies and the discovery of an immune dysregulation have induced a shift to new emerging therapies, some of which being associated with promising efficacy. The main aim of these novel immune and nonimmune strategies consists in improving survival and in increasing the number of TP53-mutated MDS/AML patients in remission amenable to allogeneic stem cell transplantation.

Emerging small molecular inhibitors as targeted therapies for high-risk acute myeloid leukemias

INTRODUCTION

Acute myeloid leukemia (AML) is an aggressive disease which has traditionally been treated with intensive chemotherapy. Survival in patients with high-risk cytogenetic and molecular subsets has been poor with this approach due to suboptimal responses seen with intensive chemotherapy and due to many patients with higher risk disease being older and unable to tolerate intensive therapies. In recent years, several targeted therapies have been under investigation for patients with high-risk AML subsets.

AREAS COVERED

This review covers four different subsets of high-risk AML including TP53-mutated, KMT2A-rearranged, FLT3-mutated, and secondary AML developing after prior hypomethylating agent exposure. The research discussed in this review focuses on small molecule inhibitors that have been studied in the treatment of these high-risk AML subsets.

EXPERT OPINION

There are several small molecule inhibitors that have demonstrated promise in these high-risk AML subsets. Longer follow-up and ongoing investigation are needed to continue to optimize therapy for patients with high-risk AML.

Basic mechanisms and novel potential therapeutic targets for ferroptosis in acute myeloid leukemia

Ferroptosis is a form of cell death that is regulated by iron and characterized by the buildup of lipid peroxides (LPO) and subsequent rupture of the cell membrane. The molecular mechanisms of ferroptosis involve metabolic pathways related to iron, lipids, and amino acids, which contribute to the production of lipid reactive oxygen species (ROS). In recent years, there has been increasing attention on the occurrence of ferroptosis in various diseases. Ferroptosis has been found to play a crucial role in cardiovascular diseases, digestive diseases, respiratory and immunological diseases, and particularly in malignancies. However, there is still a lack of studies on ferroptosis in acute myeloid leukemia (AML). This paper provides a comprehensive review of the mechanism of ferroptosis and its regulatory molecules and therapeutic agents in AML. It also evaluates the relationship between ferroptosis-related genes (FRGs), non-coding RNAs (ncRNAs), and prognosis to develop prognostic molecular models in AML. The study also explores the association between ferroptosis and immune infiltration in AML, to identify novel potential target regimens for AML.

Measurable residual disease in patients undergoing allogeneic transplant for acute myeloid leukemia

The most common indication for allogeneic hematopoietic cell transplant (alloHCT) is maintenance of remission after initial treatment for patients with acute myeloid leukemia (AML). Loss of remission, relapse, remains however the most frequent cause of alloHCT failure. There is strong evidence that detectable persistent disease burden ("measurable residual disease", MRD) in patients with AML in remission prior to alloHCT is associated with increased risk of post-transplant relapse. MRD status as a summative assessment of response to pre-transplant therapy may allow superior patient-personalized risk stratification compared with models solely incorporating pre-treatment variables. An optimal methodology for AML MRD detection has not yet been established, but molecular methods such as DNA-sequencing may have additional prognostic utility compared to current approaches. There is growing evidence that intervention on AML MRD positivity may improve post-transplant outcomes. New initiatives will generate actionable data on the clinical utility of AML MRD testing for patients undergoing alloHCT.

An Overview of Targeted Therapies in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is the most aggressive adult leukemia, characterized by clonal differentiation arrest of progenitor or precursor hematopoietic cells. Intense preclinical and clinical research has led to regulatory approval of several targeted therapeutics, administered either as single agents or as combination therapies. However, the majority of patients still face a poor prognosis and disease relapse frequently occurs due to selection of therapy-resistant clones. Hence, more effective novel therapies, most likely as innovative, rational combination therapies, are urgently needed. Chromosomal aberrations, gene mutations, and epigenetic alterations drive AML pathogenesis but concurrently provide vulnerabilities to specifically target leukemic cells. Other molecules, either aberrantly active and/or overexpressed in leukemic stem cells, may also be leveraged for therapeutic benefit. This concise review of targeted therapies for AML treatment, which are either approved or are being actively investigated in clinical trials or recent preclinical studies, provides a flavor of the direction of travel, but also highlights the current challenges in AML treatment.

Allogeneic hematopoietic cell transplantation in acute myeloid leukemia

Allogeneic hematopoietic cell transplantation (HCT) is a curative treatment modality for select patients with acute myeloid leukemia (AML), functioning as a restorative agent following intensified chemo- and/or radiotherapy and also engendering the disease-directed immunologic threat of graft-versus-leukemia effect. Advancements in conditioning regimen intensity, donor availability, and supportive care have broadened the eligibility for allogeneic HCT, reduced rates of transplant related mortality, and improved outcomes over time. There are still obstacles to transplant in AML, offering opportunities for ongoing discovery, including poor recipient fitness, insufficient donor availability for certain populations, and limited access to care. Relapse remains the most common cause of treatment failure and a high priority area of investigative efforts. Post-transplant maintenance and novel applications of cellular therapeutics are expected to usher in a new era of promise for successful HCT in AML and will aim to overcome the remaining barriers impeding favorable outcomes for these patients.

Targeting the p53 signaling pathway in cancers: Molecular mechanisms and clinical studies

Tumor suppressor p53 can transcriptionally activate downstream genes in response to stress, and then regulate the cell cycle, DNA repair, metabolism, angiogenesis, apoptosis, and other biological responses. p53 has seven functional domains and 12 splice isoforms, and different domains and subtypes play different roles. The activation and inactivation of p53 are finely regulated and are associated with phosphorylation/acetylation modification and ubiquitination modification, respectively. Abnormal activation of p53 is closely related to the occurrence and development of cancer. While targeted therapy of the p53 signaling pathway is still in its early stages and only a few drugs or treatments have entered clinical trials, the development of new drugs and ongoing clinical trials are expected to lead to the widespread use of p53 signaling-targeted therapy in cancer treatment in the future. TRIAP1 is a novel p53 downstream inhibitor of apoptosis. TRIAP1 is the homolog of yeast mitochondrial intermembrane protein MDM35, which can play a tumor-promoting role by blocking the mitochondria-dependent apoptosis pathway. This work provides a systematic overview of recent basic research and clinical progress in the p53 signaling pathway and proposes that TRIAP1 is an important therapeutic target downstream of p53 signaling.

Novel Investigational Agents and Pathways That May Influence the Future Management of Acute Myeloid Leukemia

Acute Myeloid leukemia (AML) is a clinically heterogeneous disease with a 5-year overall survival of 32% between 2012 to 2018. The above number severely dwindles with age and adverse risk of disease, presenting opportunities for new drug development and is an area of dire unmet need. Basic science and clinical investigators across the world have been working on many new and old molecule formulations and combination strategies to improve outcomes in this disease. In this review, we discuss select promising novel agents in various stages of clinical development for patients with AML.

Post-transplant maintenance therapy in acute myeloid leukemia after allogeneic hematopoietic stem cell transplantation harmonizing multiple therapeutic modalities including targeted therapy, immunotherapy and cellular therapy

Allogeneic hematopoietic stem cell transplant (HCT) has improved survival for patients with acute myeloid leukemia (AML), especially for those at high risk of relapse. However, relapse remains the leading cause of treatment failure post-HCT, occurring in around 35-45% of patients, and leading to dismal outcomes. Strategies to reduce relapse risk are urgently needed, especially in the early post-transplant period before activation of the graft-versus-leukemia (GVL) effect. Maintenance therapy is a course of treatment given post-HCT with the expectation of reducing relapse risk. While there are currently no therapies approved for maintenance therapy for AML after HCT, there are a number of studies and ongoing investigations examining the role of maintenance therapies that include targeted agents against FLT3-ITD, BCL2, or IDH mutations, hypomethylating agents, immunomodulatory therapies and cellular therapies. In this review, we discuss the mechanistic and clinical data for post-transplant maintenance therapies in AML and strategies for maintenance therapy for AML after HCT.

Ferroptosis in Haematological Malignancies and Associated Therapeutic Nanotechnologies

Haematological malignancies are heterogeneous groups of cancers of the bone marrow, blood or lymph nodes, and while therapeutic advances have greatly improved the lifespan and quality of life of those afflicted, many of these cancers remain incurable. The iron-dependent, lipid oxidation-mediated form of cell death, ferroptosis, has emerged as a promising pathway to induce cancer cell death, particularly in those malignancies that are resistant to traditional apoptosis-inducing therapies. Although promising findings have been published in several solid and haematological malignancies, the major drawbacks of ferroptosis-inducing therapies are efficient drug delivery and toxicities to healthy tissue. The development of tumour-targeting and precision medicines, particularly when combined with nanotechnologies, holds potential as a way in which to overcome these obstacles and progress ferroptosis-inducing therapies into the clinic. Here, we review the current state-of-play of ferroptosis in haematological malignancies as well as encouraging discoveries in the field of ferroptosis nanotechnologies. While the research into ferroptosis nanotechnologies in haematological malignancies is limited, its pre-clinical success in solid tumours suggests this is a very feasible therapeutic approach to treat blood cancers such as multiple myeloma, lymphoma and leukaemia.

TP53 Alterations in Myelodysplastic Syndromes and Acute Myeloid Leukemia

TP53 mutations are less frequent in myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) than in solid tumors, except in secondary and therapy-related MDS/AMLs, and in cases with complex monosomal karyotype. As in solid tumors, missense mutations predominate, with the same hotspot mutated codons (particularly codons 175, 248, 273). As TP53-mutated MDS/AMLs are generally associated with complex chromosomal abnormalities, it is not always clear when TP53 mutations occur in the pathophysiological process. It is also uncertain in these MDS/AML cases, which often have inactivation of both TP53 alleles, if the missense mutation is only deleterious through the absence of a functional p53 protein, or through a potential dominant-negative effect, or finally a gain-of-function effect of mutant p53, as demonstrated in some solid tumors. Understanding when TP53 mutations occur in the disease course and how they are deleterious would help to design new treatments for those patients who generally show poor response to all therapeutic approaches.

Overcoming relapse: prophylactic or pre-emptive use of azacitidine or FLT3 inhibitors after allogeneic transplantation for AML or MDS

Relapse remains the most critical obstacle in treatment by allogeneic hematopoietic stem cell transplantation (HSCT). Non-relapse mortality has improved annually, but relapse mortality remains high. Post-transplant maintenance treatment, such as hypomethylating agents and FMS-like tyrosine kinase 3 (FLT3) inhibitors, has been investigated for decades as a means of preventing disease relapse after HSCT. Other factors besides the relapse tendency of the primary disease that can affect the transition of estimated disease burden in patients undergoing HSCT are disease status at HSCT (non-remission, remission with minimal/measurable residual disease (MRD), and remission without MRD) and conditioning regimen intensity. Optimal selection of patients at high risk for relapse who can tolerate a long duration of therapy is pivotal for successful post-transplant maintenance therapy. In this review, we provide an overview of current progress in research on post-transplant maintenance treatment using azacitidine or FLT3 inhibitors for preventing disease relapse after HSCT for AML or MDS, and discuss the future outlook in this area.

Eprenetapopt combined with venetoclax and azacitidine in TP53-mutated acute myeloid leukaemia: a phase 1, dose-finding and expansion study

BACKGROUND

TP53-mutated acute myeloid leukaemia is associated with poor outcomes. Eprenetapopt (APR-246) is a first-in-class, small-molecule p53 reactivator. We aimed to evaluate the combination of eprenetapopt and venetoclax with or without azacitidine in patients with TP53-mutated acute myeloid leukaemia.

METHODS

This phase 1, multicentre, open-label, dose-finding and cohort expansion study was done at eight academic research hospitals in the USA. Inclusion criteria were age of at least 18 years; at least one pathogenic TP53 mutation; treatment-naive acute myeloid leukaemia according to the 2016 WHO classification; an ECOG performance status of 0-2; and a life expectancy of at least 12 weeks. In dose-finding cohort 1 patients received previous therapy with hypomethylating agents for myelodysplastic syndromes. In dose-finding cohort 2, previous use of hypomethylating agents was not permitted. Treatment cycles were 28 days. Patients in cohort 1 received intravenous eprenetapopt 4·5 g/day on days 1-4 and oral venetoclax 400 mg/day on days 1-28; those in cohort 2 also received subcutaneous or intravenous azacitidine 75 mg/m² on days 1-7. The expansion part of the study proceeded with patients enrolled as in cohort 2. Primary endpoints were safety in all cohorts (assessed in patients receiving at least one dose of assigned treatment) and complete response in the expansion cohort (assessed in patients who completed at least one treatment cycle and had at least one post-treatment clinical response assessment). The trial is registered with ClinicalTrials.gov, NCT04214860, and is complete.

FINDINGS

Between Jan 3, 2020, and July 22, 2021, 49 patients were enrolled across all cohorts. Six patients were initially enrolled into each of dose-finding cohorts 1 and 2; after no dose-limiting toxicities were observed, cohort 2 was expanded to enrol an additional 37 patients. The median age was 67 years (IQR 59-73). 24 (49%) of 49 patients were female and 25 (51%) male, and 40 (82%) were White. At data cutoff (Oct 1, 2021), the median length of follow-up was 9·5 months (IQR 6·1-11·5). No dose-limiting toxicities were recorded and the recommended phase 2 dose for eprenetapopt combinations was 4·5 g/day on days 1-4. Across all patients, adverse events of grade 3 or worse occurring in at least 20% of patients were febrile neutropenia (23 [47%] of 49 patients), thrombocytopenia (18 [37%] patients), leukopenia (12 [25%] patients), and anaemia (11 [22%] patients). Treatment-related serious adverse events occurred in 13 (27%) of 49 patients and there was one (2%) treatment-related death (sepsis). 25 (64%, 95% CI 47-79) of 39 patients had an overall response with eprenetapopt and venetoclax with azacytidine; 15 (38%, 23-55) had a complete response.

INTERPRETATION

Eprenetapopt and venetoclax with azacitidine had an acceptable safety profile and encouraging activity, supporting further frontline evaluation of this combination in the treatment of TP53-mutated acute myeloid leukaemia.

FUNDING

Aprea Therapeutics.