Randomized comparison of low dose cytarabine with or without glasdegib in patients with newly diagnosed acute myeloid leukemia or high-risk myelodysplastic syndrome

A User's Guide to Novel Therapies for Acute Myeloid Leukemia

Few diseases have been marked by a 40-year period of stagnation with regard to therapeutic advances and United States Food and Drug Administration (FDA) approvals, as has been the case for acute myeloid leukemia (AML). Cytarabine and anthracyclines were introduced for the treatment of AML in the 1970s, and in the ensuing 4 decades, the pharmacologic pipeline has experienced a standstill. The absence of FDA approvals in AML is not a reflection of the lack of understanding of the disease biology. The field has seen major advances from the standpoint of stem cell biology and clonal evolution, and the field has also seen some therapeutic advances, but these therapeutic advances have arisen from optimization of the same traditional cytotoxic chemotherapeutics rather than the development of novel therapies. The year 2017 marked a turning point with regard to FDA approvals. This review summarizes the salient clinical trials that led to the approval of 8 novel agents in AML in the past 2 years. For these agents, the clinical activity is often defined by specific molecular aberrations or metabolic features of AML cells. We also emphasize the principles of management of AML in the current era of genomic medicine, with a focus on considerations for targeting mutation-specific vulnerabilities in select patients. This review also highlights unique challenges to the use of novel agents in 2020, including considerations of curative potential with regards to bridging to allogeneic stem cell transplant, tolerability, financial toxicities, and microenvironmental hurdles. Finally, we discuss prospects on future immunotherapeutic investigational agents in the pharmacologic pipeline.

Preclinical efficacy for a novel tyrosine kinase inhibitor, ArQule 531 against acute myeloid leukemia

BACKGROUND

Acute myeloid leukemia (AML) is the most common type of adult leukemia. Several studies have demonstrated that oncogenesis in AML is enhanced by kinase signaling pathways such as Src family kinases (SFK) including Src and Lyn, spleen tyrosine kinase (SYK), and bruton's tyrosine kinase (BTK). Recently, the multi-kinase inhibitor ArQule 531 (ARQ 531) has demonstrated potent inhibition of SFK and BTK that translated to improved pre-clinical in vivo activity as compared with the irreversible BTK inhibitor ibrutinib in chronic lymphocytic leukemia (CLL) models. Given the superior activity of ARQ 531 in CLL, and recognition that this molecule has a broad kinase inhibition profile, we pursued its application in pre-clinical models of AML.

METHODS

The potency of ARQ 531 was examined in vitro using FLT3 wild type and mutated (ITD) AML cell lines and primary samples. The modulation of pro-survival kinases following ARQ 531 treatment was determined using AML cell lines. The effect of SYK expression on ARQ 531 potency was evaluated using a SYK overexpressing cell line (Ba/F3 murine cells) constitutively expressing FLT3-ITD. Finally, the in vivo activity of ARQ 531 was evaluated using MOLM-13 disseminated xenograft model.

RESULTS

Our data demonstrate that ARQ 531 treatment has anti-proliferative activity in vitro and impairs colony formation in AML cell lines and primary AML cells independent of the presence of a FLT3 ITD mutation. We demonstrate decreased phosphorylation of oncogenic kinases targeted by ARQ 531, including SFK (Tyr416), BTK, and fms-related tyrosine kinase 3 (FLT3), ultimately leading to changes in down-stream targets including SYK, STAT5a, and ERK1/2. Based upon in vitro drug synergy data, we examined ARQ 531 in the MOLM-13 AML xenograft model alone and in combination with venetoclax. Despite ARQ 531 having a less favorable pharmacokinetics profile in rodents, we demonstrate modest single agent in vivo activity and synergy with venetoclax.

CONCLUSIONS

Our data support consideration of the application of ARQ 531 in combination trials for AML targeting higher drug concentrations in vivo.

Targeted therapy in acute myeloid leukemia: current status and new insights from a proteomic perspective

Introduction: The biological heterogeneity of acute myeloid leukemia (AML) complicates personalized medicine. Individual prognosis is typically based on the presence of chromosomal and genetic lesions. Nevertheless, these classifications often lack a priori information about response to therapy. Since the protein expression landscape reflects the functional activity state of cells, we hypothesize that analyzing this can be used for the identification of protein activity markers to provide better risk stratification as well as may provide targeted therapeutic guidance in AML.Areas covered: Herein, we review recently new adopted drugs in the treatment for AML and discuss how quantitative proteomic techniques may contribute to better therapeutic selection in AML.Expert commentary: The net functional state of the cell is defined by the activity of protein within all the pathways that are active in the cell. Recognition of the proteomic profile of the leukemic blast could, therefore, complement current classification systems by providing a better a priori description of what pathways are important within a cell as a guide to the selection of therapy for the patient.

Is outcome of older people with acute myeloid leukemia improving with new therapeutic approaches and stem cell transplantation?

Introduction: The clinical outcome of older patients with acute myeloid leukemia (AML) is still poor, especially for those who are unfit to treatments aimed at altering the natural course of the disease. Hypomethylating agents (HMA) offer an important therapeutic opportunity to a consistent number of patients, but long-term results are largely unsatisfactory.Area covered: Recently, a number of new agents have been registered for AML, some of which selectively available for older patient population, with promising results in terms of response rate and survival. Furthermore, the upper age limit for allogeneic stem cell transplantation is constantly increasing, so that this procedure is offered and actually given to an increasing number of older patients with AML. A literature review was conducted of the PubMed database for articles published in English as well as for abstracts from most important and recent hematology meetings on AML in older patients.Expert opinion: Appropriate selection among different options on the basis of clinical fitness and molecular findings at diagnosis as well as at relapse would result in improvement of therapeutic results, sparing unnecessary toxicity and optimizing health systems resources.

How I treat acute myeloid leukemia in the era of new drugs

The acute myeloid leukemia (AML) treatment landscape has changed substantially since 2017. New targeted drugs have emerged, including venetoclax to target B-cell lymphoma 2, midostaurin and gilteritinib to target FLT3, and ivosidenib and enasidenib to target mutant isocitrate dehydrogenase 1 and 2, respectively. Other additions include reapproval of gemtuzumab ozogomycin to target CD33, glasdegib to target the hedgehog pathway, and a liposomal formulation of daunorubicin and cytarabine (CPX-351). Genomically heterogeneous AML has a tendency to evolve, particularly under selective treatment pressure. For decades, treatment decisions have largely centered around chemotherapy drug intensity. Physicians now have access to an increasing number of drugs with novel mechanisms of action and distinctive side-effect profiles. Key issues faced by hematologists in this era of new drugs include (1) the timely identification of actionable mutations at diagnosis and at relapse; (2) deciding which drug to use among several therapeutic options; and (3) increasing awareness of how to anticipate, mitigate, and manage common complications associated with these new agents. This article will use 3 case presentations to discuss some of the new treatment challenges encountered in AML management, with the goal of providing practical guidance to aid the practicing physician.

Recent drug approvals for newly diagnosed acute myeloid leukemia: gifts or a Trojan horse?

Since 2017 the US Food and Drug Administration (FDA) has approved glasdegib, venetoclax, ivosidenib, midostaurin, CPX- 351, and gemtuzumab ozogamicin (GO) to treat persons with newly diagnosed acute myeloid leukemia. The European Medicines Agency (EMA) has done likewise for midostaurin, CPX-351, and GO. While increasing options for persons, particularly older ones, for whom current therapy is unsatisfactory, or simply not given, these approvals raise several concerns. Although the venetoclax and glasdegib approvals were for persons considered "unfit" for intensive induction, the criteria for fitness were not well defined (age ≥75 per se being insufficient) and are frequently subjective, making it likely that many subjects in the venetoclax and glasdegib registration trials were fit for intensive induction; for example, none had performance status 3-4. Fitness must be assessed together with the potential efficacy of a proposed therapy. We note the modest complete remission rates and durations in the venetoclax + hypomethylating agent trial. Although these formed the basis for FDA approval, it is unclear that better results might not have obtained with more intense induction, as several studies, with considerably longer-follow up, have suggested. Hence, we question the venetoclax (and glasdegib) approvals absent randomized comparisons with intense induction. Given the uncertain relation in older individuals between survival and complete remission (CR), much less responses less than CR, we are skeptical of the sole use of these responses in the ivosidenib and venetoclax approvals; we also question the use of survival, without event-free survival, in the glasdegib approval. Noting the midostaurin and CPX-351 approvals included populations not participating in the registration studies we suggest means to address this issue as well as those involving fitness, randomization, and endpoints.

Therapeutic Choice in Older Patients with Acute Myeloid Leukemia: A Matter of Fitness

Acute myeloid leukemia (AML), with an incidence increasing with age, is the most common acute leukemia in adults. Concurrent comorbidities, mild to severe organ dysfunctions, and low performance status (PS) are frequently found in older patients at the onset, conditioning treatment choice and crucially influencing the outcome. Although anthracyclines plus cytarabine-based chemotherapy, also called “7 + 3” regimen, remains the standard of care in young adults, its use in patients older than 65 years should be reserved to selected cases because of higher incidence of toxicity. These adverse features of AML in the elderly underline the importance of a careful patient assessment at diagnosis as a critical tool in the decision-making process of treatment choice. In this review, we will describe selected recently approved drugs as well as examine prognostic algorithms that may be helpful to assign treatment in elderly patients properly.

The Evolving AML Genomic Landscape: Therapeutic Implications

Improved understanding of the genomic and molecular landscape of acute myeloid leukemia (AML) has resulted in a significant evolution of our understanding of AML biology and allows refined prognostication for those receiving standard combination chemotherapy induction. This dramatic increase in knowledge preceded, and was somewhat responsible for, at least some of eight new FDA drug approvals for AML. This review discusses the impact of genomics on clinical care of AML patients and highlights newly approved FDA drugs. Despite these recent clinical advances, however, the outcome for most patients diagnosed with AML remains dire. Thus, we describe here some of the challenges identified with treating AML including off-target toxicity, drug transporters, clonal heterogeneity, and adaptive resistance, and some of the most promising opportunities for improved therapy.

Acute Myeloid Leukemia: Aging and Epigenetics

Acute myeloid leukemia (AML) is an aggressive hematological disorder mainly affecting people of older age. AML initiation is primarily attributed to mutations in crucial cellular regulators such as epigenetic factors, transcription factors, and signaling genes. AML’s aggressiveness and responsiveness to treatment depends on the specific cell type where leukemia first arose. Aged hematopoietic cells are often genetically and/or epigenetically altered and, therefore, present with a completely different cellular context for AML development compared to young cells. In this review, we summarize key aspects of AML development, and we focus, in particular, on the contribution of cellular aging to leukemogenesis and on current treatment options for elderly AML patients. Hematological disorders and leukemia grow exponentially with age. So far, with conventional induction therapy, many elderly patients experience a very poor overall survival rate requiring substantial social and medical costs during the relatively few remaining months of life. The global population’s age is increasing rapidly without an acceptable equal growth in therapeutic management of AML in the elderly; this is in sharp contrast to the increase in successful therapies for leukemia in younger patients. Therefore, a focus on the understanding of the biology of aging in the hematopoietic system, the development of appropriate research models, and new therapeutic approaches are urged.

Hedgehog/GLI signaling in tumor immunity - new therapeutic opportunities and clinical implications

Uncontrolled activation of the Hedgehog/Glioma-associated oncogene (HH/GLI) pathway is a potent oncogenic driver signal promoting numerous cancer hallmarks such as proliferation, survival, angiogenesis, metastasis and metabolic rewiring. Several HH pathway inhibitors have already been approved for medical therapy of advanced and metastatic basal cell carcinoma and acute myeloid leukemia with partially impressive therapeutic activity. However, de novo and acquired resistance as well as severe side effects and unexplained lack of therapeutic efficacy are major challenges that urgently call for improved treatment options with more durable responses. The recent breakthroughs in cancer immunotherapy have changed our current understanding of targeted therapy and opened up promising therapeutic opportunities including combinations of selective cancer pathway and immune checkpoint inhibitors. Although HH/GLI signaling has been intensely studied with respect to the classical hallmarks of cancer, its role in the modulation of the anti-tumoral immune response has only become evident in recent studies. These have uncovered HH/GLI regulated immunosuppressive mechanisms such as enhanced regulatory T-cell formation and production of immunosuppressive cytokines. In light of these exciting novel data on oncogenic HH/GLI signaling in immune cross-talk and modulation, we summarize and connect in this review the existing knowledge from different HH-related cancers and chronic inflammatory diseases. This is to provide a basis for the investigation and evaluation of novel treatments combining immunotherapeutic strategies with approved as well as next-generation HH/GLI inhibitors. Further, we also critically discuss recent studies demonstrating a possible negative impact of current HH/GLI pathway inhibitors on the anti-tumoral immune response, which may explain some of the disappointing results of several oncological trials with anti-HH drugs.

Additional file 1

A Phase 1B Clinical Study of Combretastatin A1 Diphosphate (OXi4503) and Cytarabine (ARA-C) in Combination (OXA) for Patients with Relapsed or Refractory Acute Myeloid Leukemia

Combretastatin A1 (OXi4503) is a dual-function drug with vascular disrupting and cytotoxic properties that has exhibited single-agent anti-leukemia activity in murine xenograft models of acute myeloid leukemia (AML) and in a prior Phase 1A clinical study for relapsed/refractory (R/R) AML. The purpose of the present multicenter Phase 1B study was to define the maximum tolerated dose (MTD) and safety profile of OXi4503 and cytarabine (ARA-C) administered in combination (OXA). At four centers, 29 patients with R/R AML or myelodysplastic syndrome (MDS) were treated with OXA. The most common grade 3/4 treatment-emergent adverse events (AEs) were febrile neutropenia (28%), hypertension (17%), thrombocytopenia (17%), and anemia (14%). There were no treatment-emergent grade 5 AEs. Drug-related serious adverse events (SAEs) developed in 4/29 patients (14%) and included febrile neutropenia (N = 2), pneumonia/acute respiratory failure (N = 1), and hypotension (N = 1). 9.76 mg/m² was defined as the MTD of OXi4503 when administered in combination with 1 g/m² ARA-C. In 26 evaluable AML patients, there were 2 complete remissions (CR), 2 complete remissions with incomplete count recovery (CRi) and one partial response (PR), for an overall response rate (ORR) of 19%. The median overall survival (OS) time for the four patients who achieved a CR/CRi was 528 days (95% CI: 434-NA), which was significantly longer than the median OS time of 113 days (95% CI: 77-172) for the remaining 22 patients who did not achieve a CR/CRi (Log Rank Chi Square = 11.8, p-value = 0.0006). The safety and early evidence of efficacy of the OXA regimen in R/R AML patients warrant further investigation in a Phase 2 clinical study.

Treatment Strategies for Therapy-related Acute Myeloid Leukemia

Prospective evidence for management of therapy-related acute myeloid leukemia (t-AML) is limited, with evidence extrapolated from major AML trials. Optimal treatment is challenging and needs consideration of patient-specific, disease-specific, and therapy-specific factors. Clinical trials are recommended, especially for unfit patients or those with unfavorable cytogenetics or mutations. CPX-351 as an upfront intensive chemotherapy is preferred for fit patients; venetoclax with decitabine or azacitidine is an option for patients unfit for intensive chemotherapy. Hematopoietic cell transplant, the only curative option, should be offered to eligible patients with intermediate or unfavorable t-AML or patients with good-risk AML with minimal residual disease. Ongoing clinical trials focusing on treatment of t-AML, including targeted agents and immunotherapy, bode well for the future.

Venetoclax for AML: changing the treatment paradigm

Venetoclax is a specific B-cell lymphoma-2 (BCL-2) inhibitor that can restore activation of apoptosis in malignancies, the survival of which depends on dysregulation of this pathway. Preclinical data, using various model systems including cell lines and patient samples, suggested targeting BCL-2 could be a successful therapeutic strategy in patients with acute myeloid leukemia (AML). As predicted by this work, the use of venetoclax in the clinical setting has resulted in promising outcomes for patients with this disease. Although venetoclax showed limited activity as a single agent in the relapsed disease setting, recent studies have shown that when combined with a backbone therapy of a hypomethylating agent or low-dose cytarabine, high response rates with encouraging remission durations for older patients with newly diagnosed AML who were not candidates for intensive induction chemotherapy were observed. Furthermore, venetoclax-based therapies allowed for rapid responses and were able to effectively target the leukemia stem cell population. Here we review the preclinical data that supported the development of venetoclax in AML, as well as the results of the promising clinical trials.

The face of remission induction

Acute myeloid leukaemia (AML) is a heterogeneous disease in which prognosis is determined by cytogenetic and molecular aberrations as well as patient-related factors, including age, prior haematologic disorders, and comorbidities. Despite the diverse disease biology, the standard of care for remission induction therapy has changed very little since its inception in 1973. Next generation sequencing has helped to increase our knowledge of the disease pathogenesis, allowing us to develop targeted and possibly more effective treatment options. Seven new agents have been approved for the treatment of AML since 2017, all of which are directed toward a specific molecular subtype or patient population. With the advent of these therapies, a more optimal, patient-specific approach rather than the historical 'one-size fits all' model can be utilised. This review will discuss the role of these novel therapies in the remission induction setting.

Transcriptional Silencing of MCL-1 Through Cyclin-Dependent Kinase Inhibition in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is the most common adult acute leukemia. Survival remains poor, despite decades of scientific advances. Cytotoxic induction chemotherapy regimens are standard-of-care for most patients. Many investigations have highlighted the genomic heterogeneity of AML, and several new targeted therapeutic options have recently been approved. Additional novel therapies are showing promising clinical results and may rapidly transform the therapeutic landscape of AML. Despite the emerging clinical success of B-cell lymphoma (BCL)-2 targeting in AML and a large body of preclinical data supporting myeloid leukemia cell (MCL)-1 as an attractive therapeutic target for AML, MCL-1 targeting remains relatively unexplored, although novel MCL-1 inhibitors are under clinical investigation. Inhibitors of cyclin-dependent kinases (CDKs) involved in the regulation of transcription, CDK9 in particular, are being investigated in AML as a strategy to target MCL-1 indirectly. In this article, we review the basis for CDK inhibition in oncology with a focus on relevant preclinical mechanism-of-action studies of CDK9 inhibitors in the context of their therapeutic potential specifically in AML.

Single-agent and combination biologics in acute myeloid leukemia

Acute myeloid leukemia (AML) is a heterogeneous malignancy characterized by recurrent genetic, epigenetic, and metabolic abnormalities. As a result of our increasing knowledge of the underlying biology of AML leading to rational drug development, several new targeted agents have been recently added to our therapeutic arsenal. The BCL2 inhibitor venetoclax in combination with low-dose cytarabine (LDAC) or hypomethylating agents (HMAs) is safe and effective in older patients with newly diagnosed AML ineligible for intensive chemotherapy. Glasdegib, a hedgehog pathway inhibitor, may be used in combination with LDAC for the same indication and improves survival compared with LDAC alone. In newly diagnosed, fit, older patients with therapy-related AML or AML with myelodysplasia-related changes, the liposome-encapsulated combination of daunorubicin and cytarabine (CPX-351) has shown superiority over the 7 + 3 regimen. The presence of an IDH1 or IDH2 mutation can be effectively targeted by ivosidenib or enasidenib, respectively. Gemtuzumab ozogamicin improves event-free survival in CD33+ patients with favorable or intermediate-risk cytogenetics. With new targeted agents available, comprehensive genomic characterization of AML at diagnosis and relapse is increasingly necessary to select optimal treatment. Herein, we review the new single-agent and combination biologics (omitting FLT3 inhibitors, which are discussed separately) and provide recommendations on how to best use and manage patients on these regimens in clinical practice.

Targeting signalling pathways and the immune microenvironment of cancer stem cells - a clinical update

Cancer stem cells (CSCs) have important roles in tumour development, relapse and metastasis; the intrinsic self-renewal characteristics and tumorigenic properties of these cells provide them with unique capabilities to resist diverse forms of anticancer therapy, seed recurrent tumours, and disseminate to and colonize distant tissues. The findings of several studies indicate that CSCs originate from non-malignant stem or progenitor cells. Accordingly, inhibition of developmental signalling pathways that are crucial for stem and progenitor cell homeostasis and function, such as the Notch, WNT, Hedgehog and Hippo signalling cascades, continues to be pursued across multiple cancer types as a strategy for targeting the CSCs hypothesized to drive cancer progression - with some success in certain malignancies. In addition, with the renaissance of anticancer immunotherapy, a better understanding of the interplay between CSCs and the tumour immune microenvironment might be the key to unlocking a new era of oncological treatments associated with a reduced propensity for the development of resistance and with enhanced antimetastatic activity, thus ultimately resulting in improved patient outcomes. Herein, we provide an update on the progress to date in the clinical development of therapeutics targeting the Notch, WNT, Hedgehog and Hippo pathways. We also discuss the interactions between CSCs and the immune system, including the potential immunological effects of agents targeting CSC-associated developmental signalling pathways, and provide an overview of the emerging approaches to CSC-targeted immunotherapy.

New drugs approved for acute myeloid leukaemia in 2018

Acute myeloid leukaemia (AML) is a haematopoietic stem cell disorder, that is characterized by the clonal expansion of myeloid blasts and suppression of normal haematopoiesis. The 3 + 7 regimen is the backbone of standard first-line induction therapy among young/fit patients. However, in elderly and/or unfit patients with newly diagnosed AML, who cannot receive intensive chemotherapy, low-dose cytarabine or hypomethylating agents (azacitidine or decitabine) are the treatment options, which generally cannot induce durable responses. Among young/fit patients, for high-risk disease in first remission, or in cases with relapsed/refractory AML, allogeneic stem cell transplantation should be performed when complete remission is achieved. However, since AML is primarily a disease of the elderly, neither intensive chemotherapy nor allogeneic stem cell transplantation can be generally tolerated in most cases. There is clearly a need for new treatment options in elderly and young/unfit patients who cannot receive intensive chemotherapy. The discovery of novel molecular genetic markers (e.g. FMS-like tyrosine kinase 3, isocitrate dehydrogenase 1 and 2) resulted in the development of new therapeutic options in AML. This review mainly focuses on 4 targeted therapy agents; glasdegib and venetoclax used in combination treatment with low-dose cytarabine or hypomethylating agents among newly diagnosed cases with AML; and ivosidenib and gilteritinib as monotherapy in the treatment of relapsed/refractory AML, which were all approved by the US Food and Drug Administration in 2018.

Novel Therapies in Acute Myeloid Leukemia

OBJECTIVE

To provide a comprehensive review of evidence-based data on the newly approved therapeutic agents in acute myeloid leukemia (AML) with regards to appropriate indications for use, efficacy, and safety.

DATA SOURCES

Published clinical trials and observational studies.

CONCLUSION

Optimal treatment decisions for AML should be personalized based on individual patients' performance status, disease risk as determined by mutational profile, response status, and prior therapies received. While the treatment options have expanded, several questions remain regarding appropriate patient selection, long-term efficacy and safety of these agents, and sequencing of therapies among available options.

IMPLICATIONS FOR NURSING PRACTICE

Nurses need to be familiar with the peculiarities of the administration regimens of newer AML therapies, adopt formal monitoring strategies for side effects that are unique to these agents, and develop a framework to facilitate timeliness of follow-up and monitoring while on these therapies.

Diverse pathogenetic roles of SOX genes in acute myeloid leukaemia and their therapeutic implications

Acute myeloid leukaemia (AML) is a heterogeneous group of diseases with diverse pathogenetic pathways. When treated uniformly with conventional chemotherapy and allogeneic haematopoietic stem cell transplantation (HSCT), it showed variable clinical outcome and prognosis. Members of the SOX [Sry-related high-mobility group (HMG) box] gene family are involved in diverse embryonic and oncogenic processes. The roles of SOX genes in AML are not entirely clear but emerging evidence, including that arising from studies in solid-cancers, showed that SOX genes can function as tumour suppressors or oncogenes and may be involved in key pathogenetic pathways in AML involving C/EBPα mutations, activation of β-catenin/Wnt and Hedgehog pathways and aberrant TP53 signals. Recent data based on genomics and proteomics have identified key interactions between SOX genes and partnering proteins of pathogenetic significance. The observations illustrated the principles and feasibilities of developing lead molecules of potential therapeutic values. Studying the diverse pathogenetic roles of SOX genes in AML may shed lights to the heterogeneity of AML and generate information that can be translated into novel therapeutic strategies.

[What is recommended in the treatment of acute myeloid leukemia?]

Acute myeloid leukemia (AML) is characterized by a malignant transformation and proliferation of myeloid progenitor cells that cause a replacement of normal hematopoiesis. Diagnostic workup for AML includes cytogenetic analysis and mutational screening covering frequently mutated genes in AML. The genetic analysis is required for risk stratification and treatment decisions. Very recently, three novel drugs have been approved for patients who can be intensively treated: a tyrosine kinase inhibitor (midostaurin) for patients with FLT3 mutations, a liposomal formulation of chemotherapy (CPX) for patients with features of secondary AML, and a CD33 antibody-drug conjugate (gemtuzumab-ozogamicin) for AML with CD33 expression. Allogeneic stem cell transplantation remains an important treatment strategy for patients with intermediate- or high-risk AML and for patients with relapsed AML. For elderly patients who cannot undergo intensive treatment, demethylating agents are the treatment of choice. The aim is to prolong life expectancy with acceptable quality of life. In recent clinical trials, novel drugs have shown promising results in this patient population. Some of these drugs have already been approved in the US. Among these drugs are the Bcl‑2 inhibitor venetoclax, which is already approved in Germany for chronic lymphatic leukemia, as well as IDH1/IDH2 inhibitors (the latter for patients with IDH1/IDH2 mutated AML). Acute promyelocytic leukemia represents a special type of AML that should be treated with a combination of all-trans retinoic acid and arsenic trioxide leading to excellent outcome.

Glasdegib plus intensive/nonintensive chemotherapy in untreated acute myeloid leukemia: BRIGHT AML 1019 Phase III trials

Glasdegib, an oral Hedgehog pathway inhibitor, has been associated with significantly improved survival when combined with low-dose cytarabine in patients with untreated acute myeloid leukemia (AML) who were unsuitable for intensive chemotherapy, when compared with low-dose cytarabine alone. BRIGHT AML 1019 (NCT03416179) comprises two independently powered Phase III, randomized (1:1), double-blind global trials evaluating oral glasdegib 100 mg once daily or placebo plus one of two standard chemotherapy regimens in adults with untreated AML. The intensive trial combines glasdegib/placebo with cytarabine and daunorubicin (7 + 3), while the nonintensive trial combines glasdegib/placebo with azacitidine. The primary end point of both studies is overall survival. Secondary end points include response, time to and duration of response, event-free survival, safety, patient-reported outcomes and pharmacokinetics. Trial registration number: ClinicalTrials.gov identifier: NCT03416179

Venetoclax for the treatment of newly diagnosed acute myeloid leukemia in patients who are ineligible for intensive chemotherapy

Acute myeloid leukemia (AML) is an aggressive hematological malignancy with a globally poor outcome, especially in patients ineligible for intensive chemotherapy. Until recently, therapeutic options for these patients included low-dose cytarabine (LDAC) or the hypomethylating agents (HMA) azacitidine and decitabine, which have historically provided only short-lived and modest benefits. The oral B-cell lymphoma 2 inhibitor, venetoclax, Venetoclax, an oral B-cell lymphoma 2 (BCL2) inhibitor, is now approved by the USA Food and Drug Administration (FDA) in combination with LDAC or HMA in older AML patients ineligible for intensive chemotherapy. Is now approved by the US Food and Drug Administration for this indication. In the pivotal clinical trials evaluating venetoclax either in combination with LDAC or with HMA, the rates of complete remission (CR) plus CR with incomplete hematological recovery were 54% and 67%, respectively and the median overall survival (OS) was 10.4 months and 17.5 months, respectively, comparing favorably with outcomes in clinical trials evaluating single-agent LDAC or HMA. The most common adverse events with venetoclax combinations are gastrointestinal symptoms, which are primarily low grade and easily manageable, and myelosuppression, which may require delays between cycles, granulocyte colony-stimulating factor (G-CSF) administration, or decreased duration of venetoclax administration per cycle. A bone marrow assessment after the first cycle of treatment is critical to determine dosing and timing of subsequent cycles, as most patients will achieve their best response after one cycle. Appropriate prophylactic measures can reduce the risk of venetoclax-induced tumor lysis syndrome. In this review, we present clinical data from the pivotal trials evaluating venetoclax-based combinations in older patients ineligible for intensive chemotherapy, and provide practical recommendations for the prevention and management of adverse events associated with venetoclax.

Cyclin-dependent kinase (CDK) 9 and 4/6 inhibitors in acute myeloid leukemia (AML): a promising therapeutic approach

Introduction: Despite advancements over the last 2 years, outcomes for acute myeloid leukemia (AML) are poor; however, a greater comprehension of disease mechanisms has driven the investigation of new targeted treatments. Cyclin-dependent kinases (CDKs) regulate cell cycle progression, transcription and DNA repair, and are aberrantly expressed in AML. Targeting the CDK pathway is an emerging promising therapeutic strategy in AML.Areas covered: We describe the rationale for targeting CDK9 and CDK4/6, the ongoing preclinical and clinical trials and the potential of these inhibitors in AML. Our analysis included an extensive literature search via the Pubmed database and clinicaltrials.gov (March to August, 2019).Expert opinion: While CDK4/6 inhibitors are early in development for AML, CDK9 inhibition with alvocidib has encouraging clinical activity in newly diagnosed and relapsed/refractory AML. Preclinical data suggests that leukemic MCL-1 dependence may predict response to alvocidib. Moreover, MCL-1 plays a key role in resistance to BCL-2 inhibition with venetoclax. Investigational strategies of concomitant BCL-2 and CDK9 inhibition represent a promising therapeutic platform for AML. Furthermore, preclinical data suggests that CDK4/6 inhibition has selective activity in patients with KMT2A-rearrangements and FLT3 mutations. Incorporation of CDK9 and 4/6 inhibitors into the existing therapeutic armamentarium may improve outcomes in AML.

Glasdegib in the treatment of acute myeloid leukemia

Pharmacologic inhibition of the Hedgehog pathway significantly enhanced the sensitivity of leukemic cells to cytotoxic drugs. Glasdegib (PF-04449913; DAURISMO™) is a potent and selective oral inhibitor of the Hedgehog signaling pathway with clinical activity in patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS), particularly in combination with chemotherapy. The results of Phase Ib/II studies evaluating safety and efficacy of glasdegib combined with chemotherapy in previously untreated patients with AML or high-risk myelodysplastic syndrome have recently been published. In the BRIGHT AML 1003 study, glasdegib in combination with low-dose cytarabine (LDAC) was well tolerated and demonstrated a significant 54% reduction in mortality compared with LDAC for AML patients. In 2018, the US FDA approved glasdegib in combination with LDAC for the treatment of newly diagnosed patients with AML who are 75 years old or older or who have co-morbidities that preclude use of intensive induction chemotherapy.

Guadecitabine (SGI-110): an investigational drug for the treatment of myelodysplastic syndrome and acute myeloid leukemia

Introduction: The incidence of acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) is increasing with the aging population. Prognosis and overall survival (OS) remain poor in elderly patients and in those not eligible for intensive treatment. Hypomethylating agents (HMAs) have played an important role in this group of patients but their efficacy is limited. Areas covered: This article reviews the mechanism of action, pharmacology, safety profile and clinical efficacy of subcutaneous guadecitabine, a second-generation DNA methylation inhibitor in development for the treatment of AML and MDS. Expert opinion: Although guadecitabine did not yield improved complete remission (CR) rates and OS compared to the control arm in patients with treatment-naïve AML who were ineligible for intensive chemotherapy, subgroup analysis in patients who received ≥4 cycles of therapy demonstrated superior outcomes in favor of guadecitabine. Given its stability, ease of administration, safety profile and prolonged exposure time, guadecitabine would be the more appropriate HMA, replacing azacitidine and decitabine, to be used combination treatment regimens in patients with myeloid malignancies.

Recent drug approvals for acute myeloid leukemia

Acute myeloid leukemia (AML) is the most common form of acute leukemia in adults, with an incidence that increases with age, and a generally poor prognosis. The disease is clinically and genetically heterogeneous, and recent advances have improved our understanding of the cytogenetic abnormalities and molecular mutations, aiding in prognostication and risk stratification. Until recently, however, therapeutic options were mostly limited to cytotoxic chemotherapy. Since 2017, there has been an explosion of newly approved treatment options both nationally and internationally, with the majority of new drugs targeting specific gene mutations and/or pivotal cell survival pathways. In this review article, we will discuss these new agents approved for the treatment of AML within the last 2 years, and will outline the mechanistic features and clinical trials that led to their approvals.

Emerging Epigenetic Therapeutic Targets in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a genetically heterogeneous malignancy for which treatment options have been largely limited to cytotoxic chemotherapy for the past four decades. Next-generation sequencing and other approaches have identified a spectrum of genomic and epigenomic alterations that contribute to AML initiation and maintenance. The key role of epigenetic modifiers and the reversibility of epigenetic changes have paved the way for evaluation of a new set of drug targets, and facilitated the design of novel candidate treatment strategies. More recently, seven new targeted therapies have been FDA-approved demonstrating successful implementation of the past decades' research. In this review, we will summarize the most recent advances in targeted therapeutics designed for a focused group of key epigenetic regulators in AML, outline their mechanism of action and their current status in clinical development. Furthermore, we will discuss promising new approaches for epigenetic targeted treatment in AML which are currently being tested in pre-clinical trials.

Enasidenib in acute myeloid leukemia: clinical development and perspectives on treatment

Recently there has been a significant progression in the understanding of molecular mutations driving biochemical and cellular signaling changes leading to survival and proliferation of leukemia cells in patients with acute myeloid leukemia (AML). Preclinical studies have demonstrated a mutated enzyme in the citric acid cycle, isocitrate dehydrogenase (IDH), leads to the production of an oncogenic metabolite R-2-hydroxy-glutarate (R-2-HG). This causes the arrest in the differentiation of hematopoietic stem cells leading to the promotion of leukemia. Inhibitors of the IDH enzyme have been shown in preclinical studies to reduce the production of R-2-HG, resulting in terminal differentiation of leukemia blast cells. In recent phase I and II trials, the IDH2 inhibitor enasidenib has shown clinical activity in patients with relapsed and refractory (R/R) AML. This review will describe the preclinical and clinical developments of enasidenib and its Food and Drug Administration approval in R/R AML, treatment recommendations and management will be outlined.

Genetic alteration patterns and clinical outcomes of elderly and secondary acute myeloid leukemia

To illustrate the clinical and genetic features of elderly and secondary acute myeloid leukemia (AML) patients, we compared 145 elderly AML (e‐AML) and 55 secondary AML (s‐AML) patients with 451 young de novo AML patients. Both e‐AML and s‐AML patients showed lower white blood cell (WBC) and bone marrow (BM) blasts at diagnosis. NPM1, DNMT3A, and IDH2 mutations were more common while biallelic CEBPA and IDH1 mutations were less seen in e‐AML patients. s‐AML patients carried a higher frequency of KMT2A‐AF9. In treatment response and survival, e/s‐AML conferred a lower complete remission (CR) rate and shorter duration of event‐free survival (EFS) and overall survival (OS) compared with young patients. In multivariate analysis, s‐AML was an independent risk factor for OS but not EFS in the whole cohort. Importantly, intensive therapy tended to improve the survival of e/s‐AML patients without increasing the risk of early death, and hematopoietic stem cell transplantation (HSCT) could rescue the prognosis of s‐AML, which should be recommended for the treatment of fit patients.

Hedgehog pathway inhibition as a therapeutic target in acute myeloid leukemia

Introduction: The Hedgehog (HH) pathway constitutes a collection of signaling molecules which critically influence embryogenesis. In adults, however, the HH pathway remains integral to the proliferation, maintenance, and apoptosis of adult stem cells including hematopoietic stem cells. Areas covered: We discuss the current understanding of the HH pathway as it relates to normal hematopoiesis, the pathology of acute myeloid leukemia (AML), the rationale for and data from combination therapies including HH pathway inhibitors, and ultimately the prospects that might offer promise in targeting this pathway in AML. Expert opinion: Efforts to target the HH pathway have been focused on impeding this disposition and restoring chemosensitivity to conventional myeloid neoplasm therapies. The year 2018 saw the first approval of a HH pathway inhibitor (glasdegib) for AML, though for an older population and in combination with an uncommonly-used therapy. Several other clinical trials with agents targeting modulators of HH signaling in AML and MDS are underway. Further study and understanding of the interplay between the numerous aspects of HH signaling and how it relates to the augmented survival of AML will provide a more reliable substrate for therapeutic strategies in patients with this poor-risk disease.

Not Only Mutations Matter: Molecular Picture of Acute Myeloid Leukemia Emerging from Transcriptome Studies

The last two decades of genome-scale research revealed a complex molecular picture of acute myeloid leukemia (AML). On the one hand, a number of mutations were discovered and associated with AML diagnosis and prognosis; some of them were introduced into diagnostic tests. On the other hand, transcriptome studies, which preceded AML exome and genome sequencing, remained poorly translated into clinics. Nevertheless, gene expression studies significantly contributed to the elucidation of AML pathogenesis and indicated potential therapeutic directions. The power of transcriptomic approach lies in its comprehensiveness; we can observe how genome manifests its function in a particular type of cells and follow many genes in one test. Moreover, gene expression measurement can be combined with mutation detection, as high-impact mutations are often present in transcripts. This review sums up 20 years of transcriptome research devoted to AML. Gene expression profiling (GEP) revealed signatures distinctive for selected AML subtypes and uncovered the additional within-subtype heterogeneity. The results were particularly valuable in the case of AML with normal karyotype which concerns up to 50% of AML cases. With the use of GEP, new classes of the disease were identified and prognostic predictors were proposed. A plenty of genes were detected as overexpressed in AML when compared to healthy control, including KIT, BAALC, ERG, MN1, CDX2, WT1, PRAME, and HOX genes. High expression of these genes constitutes usually an unfavorable prognostic factor. Upregulation of FLT3 and NPM1 genes, independent on their mutation status, was also reported in AML and correlated with poor outcome. However, transcriptome is not limited to the protein-coding genes; other types of RNA molecules exist in a cell and regulate genome function. It was shown that microRNA (miRNA) profiles differentiated AML groups and predicted outcome not worse than protein-coding gene profiles. For example, upregulation of miR-10a, miR-10b, and miR-196b and downregulation of miR-192 were found as typical of AML with NPM1 mutation whereas overexpression of miR-155 was associated with FLT3-internal tandem duplication (FLT3-ITD). Development of high-throughput technologies and microarray replacement by next generation sequencing (RNA-seq) enabled uncovering a real variety of leukemic cell transcriptomes, reflected by gene fusions, chimeric RNAs, alternatively spliced transcripts, miRNAs, piRNAs, long noncoding RNAs (lncRNAs), and their special type, circular RNAs. Many of them can be considered as AML biomarkers and potential therapeutic targets. The relations between particular RNA puzzles and other components of leukemic cells and their microenvironment, such as exosomes, are now under investigation. Hopefully, the results of this research will shed the light on these aspects of AML pathogenesis which are still not completely understood.

Glasdegib with Low-Dose Cytarabine: A New Upfront Option for the Vulnerable AML Patient

A multitude of regulatory approvals has recently changed the therapeutic landscape of acute myeloid leukemia. Among these was upfront therapy with the Hedgehog inhibitor glasdegib with low-dose cytarabine. Understanding the process of and rationale for approval of this promising combination is timely and valuable for the oncology community.See related article by Norsworthy et al., p. 6021.

Venetoclax-based therapies for acute myeloid leukemia

The prognosis of adult acute myeloid leukemia (AML) remains poor, with the long-term survival rate less than 50%. However, the current paradigms of treatment are changing through a better understanding of the disease genetics and pathophysiology. Since 2017, eight new drugs have been approved by the U.S. Food and Drug Administration for the treatment of AML, including the FLT3 inhibitors midostaurin and gilteritinib, the IDH inhibitors ivosidenib and enasidenib, the anti-CD33 monoclonal antibody gemtuzumab ozogamicin, liposomal daunorubicin and cytarabine, the hedgehog pathway inhibitor glasdegib and the BCL-2 inhibitor venetoclax. Preclinical data demonstrated the anti-leukemic efficacy of venetoclax in AML and its synergy when combined with hypomethylating agents or chemotherapy agents. Clinical trials have demonstrated the clinical benefit of venetoclax-based therapies in newly diagnosed AML, leading to the recent FDA approval of venetoclax in combination with hypomethylating agents or low-dose cytarabine for older adults with newly diagnosed AML. Herein, we focus on the role of single-agent BCL-2 inhibition in AML and review the clinical studies of venetoclax-based combination regimens and the evolving mechanisms of resistance.

Hedgehog signaling inhibitors in solid and hematological cancers

BACKGROUND

The hedgehog signaling pathway is normally tightly regulated. Mutations in hedgehog pathway components may lead to abnormal activation. Aberrantly activated hedgehog signaling plays a major role in the development of solid and hematological cancer. In recent years, inhibitors have been developed that attenuate hedgehog signaling; 2 have been approved for use in basal cell carcinoma (BCC), while others are under development or in clinical trials. The aim of this review is to provide an overview of known hedgehog inhibitors (HHIs) and their potential for the treatment of hematological cancers and solid tumors beyond BCC.

DESIGN

Published literature was searched to identify articles relating to HHIs in noncutaneous cancer. Both preclinical and clinical research articles were included. In addition, relevant clinical trial results were identified from www.clinicaltrials.gov. Information on the pharmacology of HHIs is also included.

RESULTS

HHIs show activity in a variety of solid and hematological cancers. In preclinical studies, HHIs demonstrated efficacy in pancreatic cancer, rhabdomyosarcoma, breast cancer, and acute myeloid leukemia (AML). In clinical studies, HHIs showed activity in medulloblastoma, as well as prostate, pancreatic, and hematological cancers. Current clinical trials testing the efficacy of HHIs are underway for prostate, pancreatic, and breast cancers, as well as multiple myeloma and AML.

CONCLUSIONS

As clinical trial results become available, it will be possible to discern which additional tumor types are suited to HHI mono- or combination therapy with other anticancer agents. The latter strategy may be useful for delaying or overcoming drug resistance.

Epidemiology of acute myeloid leukemia: Recent progress and enduring challenges

Acute myeloid leukemia (AML) is a malignant disorder of the bone marrow which is characterized by the clonal expansion and differentiation arrest of myeloid progenitor cells. The age-adjusted incidence of AML is 4.3 per 100,000 annually in the United States (US). Incidence increases with age with a median age at diagnosis of 68 years in the US. The etiology of AML is heterogeneous. In some patients, prior exposure to therapeutic, occupational or environmental DNA-damaging agents is implicated, but most cases of AML remain without a clear etiology. AML is the most common form of acute leukemia in adults and has the shortest survival (5-year survival = 24%). Curative therapies, including intensive chemotherapy and allogeneic stem cell transplantation, are generally applicable to a minority of patients who are younger and fit, while most older individuals exhibit poor prognosis and survival. Differences in patient outcomes are influenced by disease characteristics, access to care including active therapies and supportive care, and other factors. After many years without therapeutic advances, several new therapies have been approved and are expected to impact patient outcomes, especially for older patients and those with refractory disease.

New Targeted Agents in Acute Myeloid Leukemia: New Hope on the Rise

The therapeutic approach for acute myeloid leukemia (AML) remains challenging, since over the last four decades a stagnation in standard cytotoxic treatment has been observed. But within recent years, remarkable advances in the understanding of the molecular heterogeneity and complexity of this disease have led to the identification of novel therapeutic targets. In the last two years, seven new targeted agents (midostaurin, gilteritinib, enasidenib, ivosidenib, glasdegib, venetoclax and gemtuzumab ozogamicin) have received US Food and Drug Administration (FDA) approval for the treatment of AML. These drugs did not just prove to have a clinical benefit as single agents but have especially improved AML patient outcomes if they are combined with conventional therapy. In this review, we will focus on currently approved and promising upcoming agents and we will discuss controversial aspects and limitations of targeted treatment strategies.

Next-Generation Hedgehog/GLI Pathway Inhibitors for Cancer Therapy

The Hedgehog/Glioma-associated oncogene homolog (HH/GLI) signaling pathway regulates self-renewal of rare and highly malignant cancer stem cells (CSC), which have been shown to account for the initiation and maintenance of tumor growth as well as for drug resistance, metastatic spread and relapse. Efficacious therapeutic approaches targeting CSC pathways, such as HH/GLI signaling in combination with chemo, radiation or immunotherapy are, therefore, of high medical need. Pharmacological inhibition of HH/GLI pathway activity represents a promising approach to eliminate malignant CSC. Clinically approved HH/GLI pathway inhibitors target the essential pathway effector Smoothened (SMO) with striking therapeutic efficacy in skin and brain cancer patients. However, multiple genetic and molecular mechanisms resulting in de novo and acquired resistance to SMO inhibitors pose major limitations to anti-HH/GLI therapies and, thus, the eradication of CSC. In this review, we summarize reasons for clinical failure of SMO inhibitors, including mechanisms caused by genetic alterations in HH pathway effectors or triggered by additional oncogenic signals activating GLI transcription factors in a noncanonical manner. We then discuss emerging novel and rationale-based approaches to overcome SMO-inhibitor resistance, focusing on pharmacological perturbations of enzymatic modifiers of GLI activity and on compounds either directly targeting oncogenic GLI factors or interfering with synergistic crosstalk signals known to boost the oncogenicity of HH/GLI signaling.

Targeting Hedgehog (Hh) Pathway for the Acute Myeloid Leukemia Treatment

The Hedgehog (Hh) pathway, containing the Patched (PTCH) and Smoothened (SMO) multitransmembrane proteins, is the main regulator of vertebrate embryonic development. A non-canonical Hh pathway was recently observed in numerous types of solid cancers and hematological malignancies. Although acute myeloid leukemia (AML) is a common and lethal myeloid malignancy, the chemotherapy for AML has not changed in the last three decades. The Hh pathway and other intracellular signaling pathways are important for the tumor cells’ cycle or therapeutic resistance of AML cells. In this article, we will review the current trends in Hh pathway inhibitors for treating AML.

Management of AML Beyond "3 + 7" in 2019

The therapeutic paradigm for treatment of acute myeloid leukemia (AML) is rapidly changing with the advent of a new generation of drugs targeting diverse aspects of leukemogenesis. Whereas standard treatment for AML until recently consisted of a classic chemotherapy backbone, the incorporation of novel agents targeting pathogenic mutations, myeloid surface markers, and apoptosis-related proteins may become a reality in the next few years. In this review, we outline the therapeutic landscape of recently approved novel agents for AML, including FLT3 inhibitors, isocitrate dehydrogenase 1/2 (IDH1/2) inhibitors, Bcl-2 antagonists, hedgehog signaling inhibitors, and immunotherapy-based approaches. Some of the future challenges in the field would be to delineate which specific patient subsets derive the most clinical benefit from a given novel agent and, furthermore, which drug combinations will yield the maximal antileukemia effect without increased toxicity. To this end, it is expected that advances in genomic and epigenomic classification of AML will facilitate a rational and optimal choice of these novel agents for AML patients.

Updates on Hematologic Malignancies in the Older Adult: Focus on Acute Myeloid Leukemia, Chronic Lymphocytic Leukemia, and Multiple Myeloma

PURPOSE OF REVIEW

Hematologic malignancies are common and difficult to treat in older adults. In this review, we focus on recent updates in diseases with several novel agents relevant to older adults-acute myeloid leukemia (AML), chronic lymphocytic leukemia (CLL), and multiple myeloma (MM).

RECENT FINDINGS

In AML, CPX-351 offers a new induction chemotherapy for secondary AML that prolongs survival, and venetoclax and IDH inhibitors are efficacious and well tolerated. In CLL, chemoimmunotherapy is being replaced by monoclonal antibodies and small molecule inhibitors that are more effective and better tolerated. In MM, new immunomodulatory drugs, proteasome inhibitors, and monoclonal antibodies have expanded treatment options for older patients. The introduction of novel agents has dramatically shifted the landscape of therapeutic options for older adults with hematologic malignancies. Clinical trials in older adults are needed to expand treatment options for these patients.

Current Therapeutic Results and Treatment Options for Older Patients with Relapsed Acute Myeloid Leukemia

Considerable progress has been made in the treatment of acute myeloid leukemia (AML). However, current therapeutic results are still unsatisfactory in untreated high-risk patients and poorer in those with primary refractory or relapsed disease. In older patients, reluctance by clinicians to treat unfit patients, higher AML cell resistance related to more frequent adverse karyotype and/or precedent myelodysplastic syndrome, and preferential involvement of chemorefractory early hemopoietic precursors in the pathogenesis of the disease further account for poor prognosis, with median survival lower than six months. A general agreement exists concerning the administration of aggressive salvage therapy in young adults followed by allogeneic stem cell transplantation; on the contrary, different therapeutic approaches varying in intensity, from conventional salvage chemotherapy based on intermediate⁻high-dose cytarabine to best supportive care, are currently considered in the relapsed, older AML patient population. Either patients' characteristics or physicians' attitudes count toward the process of clinical decision making. In addition, several new drugs with clinical activity described as "promising" in uncontrolled single-arm studies failed to improve long-term outcomes when tested in larger randomized clinical trials. Recently, new agents have been approved and are expected to consistently improve the clinical outcome for selected genomic subgroups, and research is in progress in other molecular settings. While relapsed AML remains a tremendous challenge to both patients and clinicians, knowledge of the molecular pathogenesis of the disease is fast in progress, potentially leading to personalized therapy in most patients.