Response to azacitidine is independent of p53 expression in higher-risk myelodysplastic syndromes and secondary acute myeloid leukemia

Azacitidine combined with venetoclax alleviates AML-MR with TP53 mutation in SDS: a case report and literature review

Shwachman-Diamond syndrome (SDS) is an autosomal recessive genetic disease, which is prone to transform into myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). TP53 mutation is a driving factor involved in the transformation of SDS into MDS/AML, and in the evolution of MDS to AML. Allogeneic hematopoietic stem cell transplantation (Allo-HSCT) is the only curable approach, however, challenge remains regarding the balance between efficacy and the high risk from treatment-related toxicity and mortality to achieve temporary disease control before transplantation to gain time and opportunities for transplantation. At present, pre-transplant bridging therapy has emerged as one of the important options with improved efficacy, reduced tumor burden, and less treatment-related toxicity. Here we reported azacitidine combined with venetoclax was used as pre-transplant bridging regimen in a TP53-mutant AML-MR case developed from SDS. He achieved complete remission with incomplete recovery and proceeded to Allo-HSCT. We hope to provide some evidence and insight for in-depth research and clinical treatment by presenting this case.

Enhanced ALOX12 Gene Expression Predicts Therapeutic Susceptibility to 5-Azacytidine in Patients with Myelodysplastic Syndromes

5-azacytidine (AZA), a representative DNA-demethylating drug, has been widely used to treat myelodysplastic syndromes (MDS). However, it remains unclear whether AZA's DNA demethylation of any specific gene is correlated with clinical responses to AZA. In this study, we investigated genes that could contribute to the development of evidence-based epigenetic therapeutics with AZA. A DNA microarray identified that AZA specifically upregulated the expression of 438 genes in AZA-sensitive MDS-L cells but not in AZA-resistant counterpart MDS-L/CDA cells. Of these 438 genes, the ALOX12 gene was hypermethylated in MDS-L cells but not in MDS-L/CDA cells. In addition, we further found that (1) the ALOX12 gene was hypermethylated in patients with MDS compared to healthy controls; (2) MDS classes with excess blasts showed a relatively lower expression of ALOX12 than other classes; (3) a lower expression of ALOX12 correlated with higher bone marrow blasts and a shorter survival in patients with MDS; and (4) an increased ALOX12 expression after AZA treatment was associated with a favorable response to AZA treatment. Taking these factors together, an enhanced expression of the ALOX12 gene may predict favorable therapeutic responses to AZA therapy in MDS.

Real-World Outcome and Prognostic Factors in MDS Patients Treated with Azacitidine-A Retrospective Analysis

Azacitidine (AZA) is recognized as a vital drug used in the therapy of myelodysplastic syndromes (MDS) due to its beneficial effect on survival and quality of life. Nevertheless, many patients fail to respond to AZA treatment, as prognostic factors still are not identified. The present retrospective analysis included 79 patients with MDS treated with AZA as first-line therapy in a real-life setting. The percentage of patients with good, intermediate, and poor cytogenetics was 46.8%, 11.4%, and 34.2%, respectively. The overall response rate (complete remission [CR], partial remission [PR], and hematological improvement [HI]) was 24%. The CR, PR, and HI rates were 13.9%, 2.5%, and 7.6%, respectively. Stable disease (SD) was documented in 40.5% of patients. The median overall survival (OS) and progression-free survival (PFS) were 17.6 and 14.96 months, respectively. Patients with ORR and SD had a significantly longer median OS (23.8 vs. 5.7 months, p = 0.0005) and PFS (19.8 vs. 3.5 months, p < 0.001) compared to patients who did not respond to AZA. In univariate analysis, only an unfavorable cytogenetic group was a prognostic factor of a lower response rate (p = 0.03). In a multivariate model, older age (p = 0.047), higher IPSS (International Prognostic Scoring System) risk (p = 0.014), and higher IPSS-R cytogenetic risk (p = 0.004) were independent factors of shorter OS. Independent prognostic factors for shorter PFS were age (p = 0.001), IPSS risk (p = 0.02), IPSS cytogenetic risk (p = 0.002), and serum ferritin level (p = 0.008). The safety profile of AZA was predictable and consistent with previous studies. In conclusion, our study confirms the efficacy and safety of AZA in a real-world population and identifies potential biomarkers for response and survival.

TP53 in AML and MDS: The new (old) kid on the block

MDS and AML are clonal hematopoietic stem cell disorders of increasing incidence, having a variable prognosis based, among others, on co-occurring molecular abnormalities. TP53 mutations are frequently detected in these myeloid neoplasms and portend a poor prognosis with known therapeutic resistance. This article provides a timely review of the complexity of TP53 alterations, providing updates in diagnosis and prognosis based on new 2022 International Consensus Classification (ICC) and World Health Organization (WHO) guidelines. The article addresses optimal testing strategies and reviews current and arising therapeutic approaches. While the treatment landscape for this molecular subgroup is under active development, further exploration is needed to optimize the care of this group of patients with unmet needs.

Reduced murine double minute 2 and 4 protein, but not messenger RNA , expression is associated with more severe disease in myelodysplastic syndromes and acute myeloblastic leukaemia

The human homologues of murine double minute 2 (MDM2) and 4 (MDM4) negatively regulate p53 tumour suppressor activity and are reported to be frequently overexpressed in human malignancies, prompting clinical trials with drugs that prevent interactions between MDM2/MDM4 and p53. Bone marrow samples from 111 patients with acute myeloblastic leukaemia, myelodysplastic syndrome or chronic myelomonocytic leukaemia were examined for protein (fluorescence-activated cell sorting) and messenger RNA (mRNA) expression (quantitative polymerase chain reaction) of MDM2, MDM4 and tumour protein p53 (TP53). Low protein expression of MDM2 and MDM4 was observed in immature cells from patients with excess of marrow blasts (>5%) compared with CD34⁺ /CD45^low cells from healthy donors and patients without excess of marrow blasts (<5%). The mRNA levels were indistinguishable in all samples examined regardless of disease status or blast levels. Low MDM2 and MDM4 protein expression were correlated with poor survival. These data show a poor correlation between mRNA and protein expression levels, suggesting that quantitative flow cytometry analysis of protein expression levels should be used to predict and validate the efficacy of MDM2 and MDM4 inhibitors. These findings show that advanced disease is associated with reduced MDM2 and MDM4 protein expression and indicate that the utility of MDM2 and MDM4 inhibitors may have to be reconsidered in the treatment of advanced myeloid malignancies.

Drug Repurposing by Tumor Tissue Editing

The combinatory use of drugs for systemic cancer therapy commonly aims at the direct elimination of tumor cells through induction of apoptosis. An alternative approach becomes the focus of attention if biological changes in tumor tissues following combinatory administration of regulatorily active drugs are considered as a therapeutic aim, e.g., differentiation, transdifferentiation induction, reconstitution of immunosurveillance, the use of alternative cell death mechanisms. Editing of the tumor tissue establishes new biological ‘hallmarks’ as a ‘pressure point’ to attenuate tumor growth. This may be achieved with repurposed, regulatorily active drug combinations, often simultaneously targeting different cell compartments of the tumor tissue. Moreover, tissue editing is paralleled by decisive functional changes in tumor tissues providing novel patterns of target sites for approved drugs. Thus, agents with poor activity in non-edited tissue may reveal new clinically meaningful outcomes. For tissue editing and targeting edited tissue novel requirements concerning drug selection and administration can be summarized according to available clinical and pre-clinical data. Monoactivity is no pre-requisite, but combinatory bio-regulatory activity. The regulatorily active dose may be far below the maximum tolerable dose, and besides inhibitory active drugs stimulatory drug activities may be integrated. Metronomic scheduling often seems to be of advantage. Novel preclinical approaches like functional assays testing drug combinations in tumor tissue are needed to select potential drugs for repurposing. The two-step drug repurposing procedure, namely establishing novel functional systems states in tumor tissues and consecutively providing novel target sites for approved drugs, facilitates the systematic identification of drug activities outside the scope of any original clinical drug approvals.

Targeting TP53-Mutated Acute Myeloid Leukemia: Research and Clinical Developments

TP53 is a key tumor suppressor gene that plays an important role in regulating apoptosis, senescence, and DNA damage repair in response to cellular stress. Although somewhat rare, TP53-mutated AML has been identified as an important molecular subgroup with a prognosis that is arguably the worst of any. Survival beyond one year is rare after induction chemotherapy with or without consolidative allogeneic stem cell transplant. Although response rates have been improved with hypomethylating agents, outcomes remain particularly poor due to short response duration. Improvements in our understanding of AML genetics and biology have led to a surge in novel treatment options, though the clinical applicability of these agents in TP53-mutated disease remains largely unknown. This review will focus on the epidemiology, molecular characteristics, and clinical significance of TP53 mutations in AML as well as emerging treatment options that are currently being studied.

TP53 in Myelodysplastic Syndromes

Simple Summary

The importance of gene variants in the prognosis of myelodysplastic syndromes (MDSs) has been repeatedly reported in recent years. Especially, TP53 mutations are independently associated with a higher risk category, resistance to conventional therapies, rapid transformation to leukemia, and a poor outcome. In the review, we discuss the features of monoallelic and biallelic TP53 mutations within MDS, the carcinogenic mechanisms, and the predictive value of TP53 variants in current standard treatments including hypomethylating agents, allogeneic hematopoietic stem cell transplantation, and lenalidomide, as well as the latest progress in TP53-targeted therapy strategies in MDS.

Abstract

Myelodysplastic syndromes (MDSs) are heterogeneous for their morphology, clinical characteristics, survival of patients, and evolution to acute myeloid leukemia. Different prognostic scoring systems including the International Prognostic Scoring System (IPSS), the Revised IPSS, the WHO Typed Prognostic Scoring System, and the Lower-Risk Prognostic Scoring System have been introduced for categorizing the highly variable clinical outcomes. However, not considered by current MDS prognosis classification systems, gene variants have been identified for their contribution to the clinical heterogeneity of the disease and their impact on the prognosis. Notably, TP53 mutation is independently associated with a higher risk category, resistance to conventional therapies, rapid transformation to leukemia, and a poor outcome. Herein, we discuss the features of monoallelic and biallelic TP53 mutations within MDS, their corresponding carcinogenic mechanisms, their predictive value in current standard treatments including hypomethylating agents, allogeneic hematopoietic stem cell transplantation, and lenalidomide, together with the latest progress in TP53-targeted therapy strategies, especially MDS clinical trial data.

Accuracy of bone marrow histochemical TP53 expression compared to the detection of TP53 somatic mutations in patients with myelodysplastic syndromes harbouring a del5q cytogenetic abnormality

TP53 gene mutations are common in Myelodysplastic Syndromes (MDS) with del5q and have a clinical and prognostic significance. Next Generation Sequencing (NGS) is an accurate, but expensive, technique, and not commonly available. Immunohistochemistry (IHC) for TP53 expression has been recently used as a surrogate to assess TP53 mutations. To compare the concordance between TP53 expression in IHC and TP53 mutations by NGS, 30 cases with MDS harbouring a del5q abnormality were evaluated. Overall, 10/30 patients (33.3%) had TP53 mutations by NGS, while 16/29 (55.1%) had TP53 overexpression in IHC. TP53 expression by IHC had a 70% sensitivity to identify patients with TP53 mutation by NGS, but its specificity was low (52.6%, kappa = 0.198; P = 0.24). In addition, ROC curve analyses showed that the overall diagnostic value (accuracy) of TP53 expression in IHC to identify patients with TP53 mutation by NGS was 68% in the whole study sample and 67% in patients with isolated del5q-. In both cases, the areas under the curves did not attain the statistical significance (P = 0.11 and P = 0.29, respectively). Based on the ROC curve, the cut-off of 2.3% TP53 expression in IHC was shown to be the best cut-off to identify TP53 mutations: using this cut-off, the agreement between TP53 expression and TP53 mutation by NGS reached statistical significance (kappa = 0.42; P = 0.023). In conclusion, the agreement between TP53 expression in IHC and TP53 mutation analysis by NGS is rather unsatisfactory in MDS patients with del5q at the standard cut-off. Thus, the IHC technique cannot be considered a valid alternative to NGS evaluation of TP53 mutational status in these patients.

Predicting outcome in higher-risk myelodysplastic syndrome patients treated with azacitidine

5-Azacitidine (5-AZA) is widely used for the treatment of higher-risk myelodysplastic syndromes. However, response and survival rates vary considerably, while indicated treatment duration remains undefined. For these reasons, factors determining response and survival are of major importance. Clinical, morphological, flow cytometry, cytogenetic and molecular factors are discussed in this review. Biomarkers predictive of response and prognosis, as well as their link to the mode of action of 5-AZA are also addressed, shifting the focus from clinical practice to investigational research. Their use could further improve prognostic classification of 5-AZA treated higher-risk myelodysplastic syndromes in the near future.

High-level MYC expression associates with poor survival in patients with acute myeloid leukemia and collaborates with overexpressed p53 in leukemic transformation in patients with myelodysplastic syndrome

INTRODUCTION

Patients with mutated and overexpressed p53 have an aggressive course in acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). Studies on the impact of MYC expression in AML are limited. This is the first study to evaluate MYC expression and p53 status in AML and MDS.

METHODS

We identified 214 patients, 101 AML, 79 MDS, and 34 negative control patients. We retrospectively assessed p53 and MYC expression by immunohistochemistry and correlated MYC expression with p53 expression and aberrational status of TP53.

RESULTS

The level of both p53 and MYC expression was significantly higher in AML (mean: 9.7%; 12.1%) and MDS (mean: 5.2%; 5.5%) patients compared with control cases (mean: 0.18%; 2.3%; P = .001-0.02). p53 and MYC expression levels were even more elevated in AML when compared to MDS patients (P < .001). MYC expression was significantly associated with p53 expression and TP53 aberration in AML patients but not in MDS patients (P < .001). p53 expression and >20% MYC expression showed an adverse impact on overall survival (OS) (P < .05) in AML patients while p53 but not MYC expression showed an adverse impact on OS in MDS patients. MYC and p53 dual expression, as well as combined MYC expression and TP53 aberration, showed negative impact on OS in AML patients. MDS patients with leukemic transformation revealed an interval increase in expression of both p53 and MYC.

CONCLUSION

High-level MYC expression associates with p53 abnormality and poor survival in AML. MYC may provide proliferative advantage for leukemic progression in p53 dependent and independent manner.

Role Of TP53 mutations in predicting the clinical efficacy of hypomethylating therapy in patients with myelodysplastic syndrome and related neoplasms: a systematic review and meta-analysis

Hypomethylating agents (HMAs) are now a major treatment option for myelodysplastic syndrome (MDS) and related neoplasms, but 50% of patients still do not respond and realize poor outcomes. Mutational predictors of treatment efficacy attract continuous attention. Whether TP53 mutations can be used as predictors of HMA effectiveness has caused heated debate. Therefore, we performed a meta-analysis to investigate the predictive value of TP53 mutations to outcomes of HMA therapy in patients with MDS and related neoplasms. We systematically searched PubMed, Embase, the Cochrane Library, and the WanFang databases (published deadline: September 12, 2019). The primary endpoints were overall response rate (ORR) and overall survival (OS). Odds ratio (OR), hazard ratio (HR), and 95% confidence intervals (CI) were pooled to estimate the association between TP53 mutations and the clinical efficacy of HMAs. Four hundred fifteen papers were found, and 22 papers were included in this meta-analysis (N = 2020 participants). The results showed that the presence of TP53 mutation predicted an increased overall response rate with HMA treatment in the subsets that restricted patients in de novo disease, MDS by WHO (World Health Organization) criteria, or NGS (next-generation sequence) group (P = 0.005, P = 0.003, P = 0.0005, respectively). However, TP53 mutations remained poor factors for OS (P < 0.00001). Collectively, in HMA therapy, TP53 mutations can predict better ORR when setting more refined subgroups, but TP53 mutations still strongly correlated with poor survival in hypomethylating therapy.

TP53 in Myelodysplastic Syndromes: Recent Biological and Clinical Findings

TP53 dysregulation plays a pivotal role in the molecular pathogenesis of myelodysplastic syndromes (MDS), identifying a subgroup of patients with peculiar features. In this review we report the recent biological and clinical findings of TP53-mutated MDS, focusing on the molecular pathways activation and on its impact on the cellular physiology. In MDS, TP53 mutational status is deeply associated with del(5q) syndrome and its dysregulation impacts on cell cycle, DNA repair and apoptosis inducing chromosomal instability and the clonal evolution of disease. TP53 defects influence adversely the MDS clinical outcome and the treatment response rate, thus new therapeutic approaches are being developed for these patients. TP53 allelic state characterization and the mutational burden evaluation can therefore predict prognosis and identify the subgroup of patients eligible for targeted therapy. For these reasons, in the era of precision medicine, the MDS diagnostic workup cannot do without the complete assessment of TP53 mutational profile.

Prognostic value of indoleamine 2,3 dioxygenase in patients with higher-risk myelodysplastic syndromes treated with azacytidine

Hypomethylating agents (HMAs) are widely used in patients with higher-risk myelodysplastic syndromes (MDS) not eligible for stem cell transplantation; however, the response rate is <50%. Reliable predictors of response are still missing, and it is a major challenge to develop new treatment strategies. One current approach is the combination of azacytidine (AZA) with checkpoint inhibitors; however, the potential benefit of targeting the immunomodulator indoleamine-2,3-dioxygenase (IDO-1) has not yet been evaluated. We observed moderate to strong IDO-1 expression in 37% of patients with high-risk MDS. IDO-1 positivity was predictive of treatment failure and shorter overall survival. Moreover, IDO-1 positivity correlated inversely with the number of infiltrating CD8⁺ T cells, and IDO-1+ patients failed to show an increase in CD8⁺ T cells under AZA treatment. In vitro experiments confirmed tryptophan catabolism and depletion of CD8⁺ T cells in IDO-1+ MDS, suggesting that IDO-1 expression induces an immunosuppressive microenvironment in MDS, thereby leading to treatment failure under AZA treatment. In conclusion, IDO-1 is expressed in more than one-third of patients with higher-risk MDS, and is predictive of treatment failure and shorter overall survival. Therefore, IDO-1 is emerging as a promising predictor and therapeutic target, especially for combination therapies with HMAs or checkpoint inhibitors.

Higher-risk myelodysplastic syndromes with del(5q): does the del(5q) matter?

Introduction: Myelodysplastic Syndrome (MDS) represents a group of cancers characterized by abnormal blood cell formation and maturation, leading to various degrees of cytopenias and potential transformation to acute myeloid leukemia. Deletion of the long arm of chromosome 5 (del(5q)) is the most common clonal chromosomal anomaly in MDS, yet the population in this disease subtype is quite heterogeneous. This manuscript analyzes literature on high-risk MDS with del(5q) abnormalities.Areas covered: The paper will review outcomes with lenalidomide among high-risk MDS patients with del(5q). It will discuss the implications of harboring TP53 gene mutations, and share the data for allogeneic hematopoietic stem cell transplantations in this setting. Finally, the report evaluates the risk of disease progression in these patients.Expert commentary: Improved characterization of MDS has enhanced our understanding of patients with anomalies involving del(5q). Emerging literature is exploring combination therapy beyond lenalidomide, and next-generation sequencing may identify secondary mutations that could be an additional avenue for treatment.

Comparison between 5-day decitabine and 7-day azacitidine for lower-risk myelodysplastic syndromes with poor prognostic features: a retrospective multicentre cohort study

Numerous studies have analysed the clinical efficacies of hypomethylating agents (HMAs) in patients with myelodysplastic syndromes (MDS). However, reports that compare the two HMAs, decitabine and azacitidine, in patients with lower-risk (low and intermediate-1) MDS are limited. We compared 5-day decitabine and 7-day azacitidine regimens in terms of treatment responses, survival outcomes, and adverse events in patients with lower-risk MDS with poor prognostic features. The overall response rates (ORRs) were 67.2% and 44.0% in the patients treated with decitabine and azacitidine, respectively (P = 0.014). While the median progression-free survival (PFS) was significantly better in the patients treated with decitabine than in those treated with azacitidine (P = 0.019), no significant differences in event-free and overall survival rates were observed between the two groups. Multivariate analysis revealed that compared with azacitidine treatment, decitabine treatment is significantly associated with a higher ORR (P = 0.026) and longer PFS (P = 0.037). No significant differences were observed in the incidence of grade 3 or higher haematologic adverse events in response to the two HMAs. In conclusion, in lower-risk MDS, especially with poor prognostic features, ORR and PFS were significantly better with 5-day decitabine treatment than with 7-day azacitidine treatment, with comparable safety.

Prognostic significance of the tumor suppressor protein p53 gene in childhood acute lymphoblastic leukemia

The tumor suppressor protein p53 (TP53) gene is associated with various types of cancer; however, little is known about TP53 expression in patients with childhood acute lymphoblastic leukemia (ALL). The aim of the present study was to investigate the prognostic value of TP53 expression in childhood ALL. To achieve this, TP53 mRNA levels of 146 children with ALL and 23 child donors with idiopathic thrombocytopenic purpura were determined by reverse transcription-quantitative PCR. Relapse-free survival (RFS) and overall survival (OS) were analyzed using the Kaplan-Meier method. The results demonstrated that TP53 mRNA level in patients with ALL was higher compared with that in the ITP donors (P=0.019). Patients with highly-expressed TP53 exhibited lower percentages of peripheral blood blast, higher platelet counts and inferior complete remission rates compared with patients with low expression of TP53. Survival analyses revealed that high TP53 expression was associated with poor OS and RFS in childhood ALL (P=0.018 and P=0.028, respectively) and was an independent prognostic factor in multivariate analysis for poor RFS (P<0.001) and OS (P<0.001). In conclusion, high TP53 expression is associated with poor outcomes and may be used as a molecular prognostic marker to be incorporated into an improved risk classification system for childhood ALL.

Can we predict responsiveness to hypomethylating agents in AML?

DNA-hypomethylating agents (HMAs) were developed as nonintensive treatment alternatives to standard chemotherapy in older, unfit patients with acute myeloid leukemia and myelodysplastic syndrome. Given their distinct effects on the methylome and transcriptome of malignant cells compared to cytarabine (Ara-C) and other cytotoxic drugs not inhibiting DNA methyltransferases, it is of great interest to define their specific clinical ``signature.'' Here, we present and discuss clinical, genetic, and epigenetic predictors of responsiveness to HMAs. Indeed, mounting evidence supports the notion that HMAs are not "just another kind of low-dose Ara-C." Not only patient factors (age, performance status, comorbidities, etc.), blast counts, and early platelet response, but also adverse genetics (monosomal karyotype and/or a TP53 mutation) have predictive potential. Given the surprising-and initially counterintuitive-responses observed in patients with the latter features, these are subject to mechanistic studies to elucidate their as yet unresolved interaction with HMAs. Finally, other potential biomarkers for HMA response such as elevated fetal hemoglobin might also contribute to overcome the present challenges in predicting responsiveness to HMAs.

Histological evaluation of myeloproliferative neoplasms

In 2017, the revised World Health Organization was published. Regarding myeloproliferative neoplasms, histological findings of bone marrow biopsy is becoming more important for diagnosis. This article highlights particularly the morphology of megakaryocytes and evaluation of myelofibrosis for pathological diagnosis, and immunohistochemistry which can detect somatic mutation.

Bridging Strategies to Allogeneic Transplant for Older AML Patients

Treatment options for older patients with intermediate or high-risk acute myeloid leukemia (AML) remain unsatisfactory. Allogeneic stem cell transplantation, the treatment of choice for the majority of younger AML patients, has been hampered in elderly patients by higher treatment related mortality, comorbidities and lack of a suitable donor. With the higher availability of suitable donors as well as of reduced intensity conditioning regimens, novel low intensity treatments prior to transplantation and optimized supportive care, the number of older AML patients being successfully transplanted is steadily increasing. Against this background, we review current treatment strategies for older AML patients planned for allogeneic stem cell transplantation based on clinical trial data, discussing differences between approaches with advantages and pitfalls of each. We summarize pre-treatment considerations that need to be taken into account in this highly heterogeneous older population. Finally, we offer an outlook on areas of ongoing clinical research, including novel immunotherapeutic approaches that may improve access to curative therapies for a larger number of older AML patients.

Efficacy of azacitidine is independent of molecular and clinical characteristics - an analysis of 128 patients with myelodysplastic syndromes or acute myeloid leukemia and a review of the literature

Azacitidine is the first drug to demonstrate a survival benefit for patients with MDS. However, only half of patients respond and almost all patients eventually relapse. Limited and conflicting data are available on predictive factors influencing response. We analyzed 128 patients from two institutions with MDS or AML treated with azacitidine to identify prognostic indicators. Genetic mutations in ASXL1, RUNX1, DNMT3A, IDH1, IDH2, TET2, TP53, NRAS, KRAS, FLT3, KMT2A-PTD, EZH2, SF3B1, and SRSF2 were assessed by next-generation sequencing. With a median follow up of 5.6 years median survival was 1.3 years with a response rate of 49%. The only variable with significant influence on response was del(20q). All 6 patients responded (p = 0.012) but survival was not improved. No other clinical, cytogenetic or molecular marker for response or survival was identified. Interestingly, patients from poor-risk groups as high-risk cytogenetics (55%), t-MDS/AML (54%), TP53 mutated (48%) or relapsed after chemotherapy (60%) showed a high response rate. Factors associated with shorter survival were low platelets, AML vs. MDS, therapy-related disease, TP53 and KMT2A-PTD. In multivariate analysis anemia, platelets, FLT3-ITD, and therapy-related disease remained in the model. Poor-risk factors such as del(7q)/-7, complex karyotype, ASXL1, RUNX1, EZH2, and TP53 did not show an independent impact. Thus, no clear biomarker for response and survival can be identified. Although a number of publications on predictive markers for response to AZA exist, results are inconsistent and improved response rates did not translate to improved survival. Here, we provide a comprehensive overview comparing the studies published to date.

DNA Methyltransferase Inhibitors in Myeloid Cancer: Clonal Eradication or Clonal Differentiation?

DNA methyltransferase inhibitors, so-called hypomethylating agents (HMAs), are the only drugs approved for the treatment of higher-risk myelodysplastic syndromes and are widely used in this context. However, it is still unclear why some patients respond to HMAs, whereas others do not. Recent sequencing efforts have identified molecular disease entities that may be specifically sensitive to these drugs, and many attempts are being made to clarify how HMAs affect the malignant clone during treatment. Here, we review the most recent data on the clinical effects of HMAs in myeloid malignancies.

Selective inhibition of BCL-2 is a promising target in patients with high-risk myelodysplastic syndromes and adverse mutational profile

Somatic mutations in genes such as ASXL1, RUNX1, TP53 or EZH2 adversely affect the outcome of patients with myelodysplastic syndromes (MDS). Since selective BCL-2 inhibition is a promising treatment strategy in hematologic malignancies, we tested the therapeutic impact of ABT-199 on MDS patient samples bearing an adverse mutational profile. By gene expression, we found that the level of pro-apoptotic BIM significantly decreased during MDS disease progression in line with an acquired resistance to cell death. Supporting the potential for ABT-199 treatment in MDS, high-risk MDS patient samples specifically underwent cell death in response to ABT-199 even when harbouring mutations in ASXL1, RUNX1, TP53 or EZH2. ABT-199 effectively targeted the stem- and progenitor compartment in advanced MDS harbouring mutations in ASXL1, RUNX1, TP53 or EZH2 and even proved effective in patients harbouring more than one of the defined high-risk mutations. Moreover, we utilized the protein abundance of BCL-2 family members in primary patient samples using flow cytometry as a biomarker to predict ABT-199 treatment response. Our data demonstrate that ABT-199 effectively induces apoptosis in progenitors of high-risk MDS/sAML despite the presence of adverse genetic mutations supporting the notion that pro-apoptotic intervention will hold broad therapeutic potential in high-risk MDS patients with poor prognosis.

Systematic review of azacitidine regimens in myelodysplastic syndrome and acute myeloid leukemia

Background

5-Azacitidine administered as a 7-day dosing regimen (7–0-0) is approved in high risk IPSS myelodysplastic syndrome (MDS) patients. Alternative regimens such as a 5-day (5–0-0) or 7-day with a weekend break (5–2-2) are commonly used. No randomized controlled trial has been done directly comparing all three dosing regimens. The objective of this study was to compare the efficacies of the 5–0-0, 5–2-2, and 7–0-0 regimens in MDS and AML.

Methods

A systematic review was conducted using MEDLINE, EMBASE and CENTRAL. Eligible studies were randomized controlled trials (RCTs), observational prospective and retrospective studies. The primary clinical outcomes were Objective Response Rate (ORR) defined as the sum of complete response (CR), partial response (PR), and hematological improvement (HI) as defined by the IWG 2006 criteria. A meta-analysis of simple proportions was conducted using a random effects model with weights defined according to Laird and Mosteller. Comparisons between groups were not attempted due to the heterogeneity of study designs.

Results

The only RCT directly comparing alternative azacitidine regimens showed no difference in ORR between the 5–0-0 and 5–2-2 regimens. All other RCTs compared a dosing regimen to conventional care. The pooled proportion of ORR was 44.8% with 95% CI (42.8%, 45.5%) for 7–0-0, 41.2% with 95% CI (39.2%, 41.9%) for 5–0-0, and 45.8% with 95% CI (42.6%, 46.4%) for 5–2-2.

Conclusions

Indirect comparison of alternative azacitidine dosing regimens in MDS and AML shows a benefit for the 7-day regimen in attaining ORR. Additional RCTs are required to definitively address this comparison.

Electronic supplementary material

The online version of this article (10.1186/s12878-017-0094-8) contains supplementary material, which is available to authorized users.

Recent advances in the cellular and molecular understanding of myelodysplastic syndromes: implications for new therapeutic approaches

It has been more than 10 years since any new disease-modifying therapies have received regulatory approval for indications related to myelodysplastic syndromes (MDS). Advances in our collective biological understanding of MDS in the last decade, however, have made it possible to hope that effective therapeutics can be designed to improve MDS-associated cytopenias and patients' quality of life, and perhaps even delay clonal progression and extend survival. Classes of MDS-associated mutations and disordered biological pathways targeted by developmental therapeutics include the following: aberrant messenger RNA splicing, neomorphic enzymes in the citric acid cycle with oncogenic activity, overactivated tyrosine and serine-threonine kinases, epigenetic and chromatin remodeling alterations, abnormal telomere dynamics, and failed protection of DNA integrity. At present, treatments for MDS are usually administered as sequential monotherapy, but there is a trend toward clinical trials of combination therapies-in which new agents are added to a DNA hypomethylating agent backbone-for both upfront treatment and the treatment of relapsed/refractory disease. Agents in clinical trials for subsets of MDS include luspatercept, antibodies targeting CD33, isocitrate dehydrogenase inhibitors, deacetylase inhibitors, venetoclax, and immunotherapies designed to overcome immune checkpoint inhibition. These biologically based therapeutics, as well as the encouraging precedent of 7 new approvals by the US Food and Drug Administration in 2017 for the treatment of acute leukemia, offer the prospect that 10 more years will not elapse before another new therapy is approved for MDS.

New Insight Into the Biology, Risk Stratification, and Targeted Treatment of Myelodysplastic Syndromes

In myelodysplastic syndromes (MDS), somatic mutations occur in five major categories: RNA splicing, DNA methylation, activated cell signaling, myeloid transcription factors, and chromatin modifiers. Although many MDS cases harbor more than one somatic mutation, in general, there is mutual exclusivity of mutated genes within a class. In addition to the prognostic significance of individual somatic mutations, more somatic mutations in MDS have been associated with poor prognosis. Prognostic assessment remains a critical component of the personalization of care for patient with MDS because treatment is highly risk adapted. Multiple methods for risk stratification are available with the revised International Prognostic Scoring System (IPSS-R), currently considered the gold standard. Increasing access to myeloid gene panels and greater evidence for the diagnostic and predictive value of somatic mutations will soon make sequencing part of the standard evaluation of patients with MDS. In the absence of formal guidelines for their prognostic use, well-validated mutations can still refine estimates of risk made with the IPSS-R. Not only are somatic gene mutations advantageous in understanding the biology of MDS and prognosis, they also offer potential as biomarkers and targets for the treatment of patients with MDS. Examples include deletion 5q, spliceosome complex gene mutations, and TP53 mutations.

Treatment of Low-Blast Count AML using Hypomethylating Agents

In 2002, the WHO classification reduced the proportion of blasts in the bone marrow (BM) necessary for the diagnosis of acute myeloid leukemia (AML) from 30% to 20%, eliminating the RAEB-t subtype of myelodysplastic syndromes (MDS). However, this AML subtype, defined as low-blast count AML (LBC-AML, with 20-30% BM-blasts) is characterized by peculiar features, as increased frequency in elderly individuals and after cytotoxic treatment for a different primary disease (therapy-related), poor-risk cytogenetics, lower white blood cell counts, and less frequent mutations of NPM1 and FLT3 genes. The clinical course of this entity is often similar to MDS with 10-19% BM-blasts. The hypomethylating agents azacitidine and decitabine have been shown to induce responses and prolong survival both in MDS and LBC-AML. The role of these agents has also been demonstrated in AML with >30% BM-blasts, particularly in patients with poor-risk cytogenetics and in AML with myelodysplasia-related changes. Most recent studies are evaluating strategies to improve outcome, including combinations of hypomethylating agents with immune-response checkpoint inhibitors, which have a role in cancer immune surveillance. Efforts are also ongoing to identify mutations which may predict response and survival in these patients.

p53 protein expression in patients with myelodysplasia treated with allogeneic bone marrow transplantation

Tumor protein 53 mutations adversely affect the prognosis of myelodysplastic syndromes (MDS); however, few studies have reported on the prognostic significance of the expression of p53 protein in MDS. The current study investigated p53 immunoreactivity (p53-IR) in bone marrow biopsies (BMBs) obtained at diagnosis from 18 patients (6 females and 12 males; mean age, 50.5 years) with MDS that underwent bone marrow transplantation (BMT) to determine the associations between clinical and histopathological data and outcome. There were 5 refractory cytopenia with multilineage dysplasia (RCMD) and 13 refractory anemia with excess blasts, type 2 (RAEB-2) cases. p53-IR was assessed as the percentage of hematopoietic cells exhibiting intense nuclear staining. The cut off for positivity was 5% of stained cells. A positive p53-IR was detected in 7 patients (38.9%) and was associated with age (P=0.005) and pattern of BM fibrosis (P=0.03). A positive p53-IR was more frequent in females, in highly cellular BMBs and in RAEB-2 cases. Overall survival (OS) was associated with patients' age (P=0.01), hemoglobin level (P=0.04), type of MDS (P=0.05), degree of BM fibrosis (P=0.006) and number of BM blasts (P=0.05). The OS of patients with negative p53-IR tended to be longer compared with that of patients with positive p53-IR, although this difference was not statistically significant (P=0.1). Despite the limitation of the low number of cases, the present results indicate that a positive p53-IR at diagnosis is associated with clinically more aggressive MDS subtypes and adverse histological prognostic factors, such as BM fibrosis. Therefore, the evaluation of p53 expression of BMBs of patients with MDS may be introduced in the histopathological work-up of the disease.

Immunohistochemistry for p53 is a useful tool to identify cases of acute myeloid leukemia with myelodysplasia-related changes that are TP53 mutated, have complex karyotype, and have poor prognosis

In this study, we evaluate the expression of p53 in core biopsies with acute myeloid leukemia and correlate the level of expression with acute myeloid leukemia subtype, TP53 mutation status, karyotype, and survival. Of the 143 cases evaluated, 71 fulfilled the WHO 2016 criteria for acute myeloid leukemia with myelodysplasia-related changes, 40 were acute myeloid leukemia-not otherwise specified, 25 were acute myeloid leukemia with recurrent genetic abnormalities, and 7 were therapy-related acute myeloid leukemia. By immunohistochemistry, 17% showed p53 expression in >5% of the cells. Of the 24 cases with >5% p53-positive cells, 17 were acute myeloid leukemia with myelodysplasia-related changes, 5 were acute myeloid leukemia-not otherwise specified, 1 was acute myeloid leukemia with recurrent genetic abormalities, and 1 was therapy-related acute myeloid leukemia. In cases for which data was available, expression of >5% p53-positive cells was significantly associated with genotype (n=67) and/or karyotype (n=130). Among the 115 cases for which clinical follow up was available, the overall survival of cases with p53 expression >15% (Median=102 days) was significantly shorter compared with cases with p53 expression ≤15% (Median=435 days). Within the acute myeloid leukemia with myelodysplasia-related changes group, this association remained significant, with cases with ≤15% p53-positive cells having a median overall survival of 405 days versus 102 days for cases with >15% p53-positive cells. Among acute myeloid leukemia with myelodysplasia-related changes cases with a complex karyotype, the finding of >15% p53-positive cells was significantly associated with worse overall survival. The poor prognosis associated with more than 15% p53-positive cells was independent of age and karyotype. In acute myeloid leukemia with myelodysplasia-related changes, p53 expression may be useful to infer TP53 mutation status, complex karyotype, and/or poor prognosis in situations where other modalities are not readily available.

Efficacy of Azacitidine in the treatment of adult patients aged 65 years or older with AML

INTRODUCTION

Therapy for acute myeloid leukemia (AML) in elderly populations (>65 years) is still a challenge for scientists and hematologists worldwide, and represents an urgent medical need. Notably, the identification and the recognition of molecular and epigenetic mechanisms involved in the pathogenesis of such a heterogeneous disease, are providing new tools for a more successful and 'targeted' approach. Azacitidine is a hypomethylating agent (HMA) with relevant activity in patients affected by myelodysplastic syndrome (MDS) and AML with low blast cells percentage (>30%), in terms of reduction of transfusion dependence, and improvement of quality of life. Areas covered: This review summarizes the mechanism of action, safety profile and efficacy of azacitidine in the field of elderly AML populations, providing up-to-date references on this subset of high-risk patients. Expert opinion: HMAs are the first successful treatment for elderly patients with high-risk MDS and are effective for some AML subtypes. Translational studies based on gene expression profiling and molecular sequencing, would be able to identify, in the near future, patients with a favorable profile of response to these compounds suggesting new potential treatment combinations also.

A clinical-molecular update on azanucleoside-based therapy for the treatment of hematologic cancers

The azanucleosides azacitidine and decitabine are currently used for the treatment of acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) in patients not only eligible for intensive chemotherapy but are also being explored in other hematologic and solid cancers. Based on their capacity to interfere with the DNA methylation machinery, these drugs are also referred to as hypomethylating agents (HMAs). As DNA methylation contributes to epigenetic regulation, azanucleosides are further considered to be among the first true “epigenetic drugs” that have reached clinical application. However, intriguing new evidence suggests that DNA hypomethylation is not the only mechanism of action for these drugs. This review summarizes the experience from more than 10 years of clinical practice with azanucleosides and discusses their molecular actions, including several not related to DNA methylation. A particular focus is placed on possible causes of primary and acquired resistances to azanucleoside treatment. We highlight current limitations for the success and durability of azanucleoside-based therapy and illustrate that a better understanding of the molecular determinants of drug response holds great potential to overcome resistance.

CTNNA1 hypermethylation, a frequent event in acute myeloid leukemia, is independently associated with an adverse outcome

The aim of this study is to evaluate the frequency of CTNNA1 hypermethylation in acute myeloid leukemia (AML) patients in an attempt to improve molecular prognostic model. CTNNA1 promoter methylation levels in 319 newly diagnosed AML patients were detected using quantitative methylation-specific polymerase chain reaction (qMS-PCR). Furthermore, hematological characteristics, cytogenetic abnormalities, and genetic mutation status were analyzed, followed by assessment of clinical impact. Our findings demonstrated that CTNNA1 hypermethylation was observed in 25% AML patients. Hypermethylation of the CTNNA1 promoter was associated with unfavorable karyotype, and also possessed the higher frequency of coexisting with ASXL1 and RUNX1 mutations. Patients with CTNNA1 hypermethylation exhibited the shorter relapse-free survival (RFS) and overall survival (OS) in the whole AML and non-M3 AML patients. Moreover, patients with the higher methylation levels had more aggressive course than those with relative lower levels. In multivariate analyses, CTNNA1 hypermethylation was an independent factor predicting for poor RFS, but not for OS. In conclusion, CTNNA1 hypermethylation may be a reliable factor for improving prognostic molecular model for AML.

Correlation of somatic mutations with outcome after FLAMSA-busulfan sequential conditioning and allogeneic stem cell transplantation in patients with myelodysplastic syndromes

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative treatment option for myelodysplastic syndromes (MDS). Little is known about the prognostic impact of mutations, for example, in TP53 specifically after allo-HSCT. We here describe the prognostic impact of mutations in a panel of 19 genes analyzed by amplicon-based next-generation-sequencing in a uniformly treated patient cohort. Sixty-two patients with a median age of 61 yr suffered from MDS with 0-20% bone marrow blasts. International Prognostic Score was intermediate 1 (15%) and higher (79%). Conditioning uniformly was performed using a sequential approach in which FLAMSA chemotherapy was followed by Busulfan-based conditioning. Patients mostly were transplanted from an unrelated donor (77%), and 36% of patients received a graft from a mismatched donor. Median number of mutations was 2 (range 0-6). RUNX1, GATA2, TET2, and CEBPA were the genes most frequently found mutated. TP53, a factor previously reported to confer adverse prognostic impact after allogeneic stem cell transplantation, was mutated in samples from eight patients, one of which showed a silent mutation. With an estimated 5-yr overall/disease-free survival of 48 ± 7%/41 ± 7%, none of the mutations analyzed showed a prognostic impact in this analysis of the largest uniformly treated cohort thus far. This especially holds true for patients with a mutation in TP53.

TP53 mutation in patients with high-risk acute myeloid leukaemia treated with allogeneic haematopoietic stem cell transplantation

Treatment success in patients with acute myeloid leukaemia (AML) is heterogeneous. Cytogenetic and molecular alterations are strong prognostic factors, which have been used to individualize treatment. Here, we studied the impact of TP53 mutations on the outcome of AML patients with adverse cytogenetic risk treated with allogeneic haematopoietic stem cell transplantation (HSCT). Samples of 97 patients with AML and adverse-risk cytogenetics who had received a HSCT within three randomized trials were analysed. Complete sequencing of the TP53 coding region was performed using next generation sequencing. The median age was 51 years. Overall, TP53 mutations were found in 40 patients (41%). With a median follow up of 67 months, the three-year probabilities of overall survival (OS) and event-free survival for patients with TP53 wild type were 33% [95% confidence interval (CI), 21% to 45%] and 24% (95% CI, 13% to 35%) compared to 10% (95% CI, 0% to 19%) and 8% (95% CI, 0% to 16%) (P = 0·002 and P = 0·007) for those with mutated TP53, respectively. In multivariate analysis, the TP53-mutation status had a negative impact on OS (Hazard Ratio = 1·7; P = 0·066). Mutational analysis of TP53 might be an important additional tool to predict outcome after HSCT in patients with adverse karyotype AML.

Treatment with 5-Azacytidine improves clinical outcome in high-risk MDS patients in the 'real life' setting: A single center observational study

OBJECTIVES

The demethylating factor 5-Azacytidine (5-AZA) improves survival of patients with myelodysplastic syndromes (MDS) in randomized control trials but the results in 'real life' are controversial.

METHODS

In this retrospective study, we evaluated the outcome of 56 high-risk MDS patients who were treated with 5-AZA between 2005 and 2013. 5-AZA was administered in an outpatient basis at a dose 75 mg/m(2) s.c. with the following schedule: 5 days on/weekend off/2 days on (5/2/2).

RESULTS

The overall response rate (ORR) was 50%; 21.2% patients achieved complete response (CR), 3.8% partial response (PR), and 25% hematologic improvement (HI); 34.6% had stable disease (SD) and 15.4% showed progressive disease (PD). The estimated median event free survival (EFS) and overall survival (OS) were 11 and 17 months, respectively. Interestingly, the estimated time to acute myeloid leukemia transformation was 30 months, which refers to patients who responded to AZA treatment or remained stable. Patients who responded to the 5-AZA achieving CR, PR, and HI had better EFS and OS compared to the patients who had SD or PD. In addition, Δ WHO Classification-based Prognostic Score System (ΔWPSS), which represents the improvement of WPSS risk group before and after treatment, was associated with significantly improved OS and better EFS. Finally, the response to treatment was not associated with the expression of p53.

CONCLUSIONS

In conclusion, 5-AZA is an effective treatment for high-risk MDS. Improved OS and EFS were found mainly in patients who responded to the treatment while ΔWPSS seems to represent a promising future prognostic tool.

Blockade of BCL-2 proteins efficiently induces apoptosis in progenitor cells of high-risk myelodysplastic syndromes patients

Deregulated apoptosis is an identifying feature of myelodysplastic syndromes (MDS). Whereas apoptosis is increased in the bone marrow (BM) of low-risk MDS patients, progression to high-risk MDS correlates with an acquired resistance to apoptosis and an aberrant expression of BCL-2 proteins. To overcome the acquired apoptotic resistance in high-risk MDS, we investigated the induction of apoptosis by inhibition of pro-survival BCL-2 proteins using the BCL-2/-XL/-W inhibitor ABT-737 or the BCL-2-selective inhibitor ABT-199. We characterized a cohort of 124 primary human BM samples from MDS/secondary acute myeloid leukemia (sAML) patients and 57 healthy, age-matched controls. Inhibition of anti-apoptotic BCL-2 proteins was specifically toxic for BM cells from high-risk MDS and sAML patients, whereas low-risk MDS or healthy controls remained unaffected. Notably, ABT-737 or ABT-199 treatment was capable of targeting the MDS stem/progenitor compartment in high-risk MDS/sAML samples as shown by the reduction in CD34(+) cells and the decreased colony-forming capacity. Elevated expression of MCL-1 conveyed resistance against both compounds. Protection by stromal cells only partially inhibited induction of apoptosis. Collectively, our data show that the apoptotic resistance observed in high-risk MDS/sAML cells can be overcome by the ABT-737 or ABT-199 treatment and implies that BH3 mimetics might delay disease progression in higher-risk MDS or sAML patients.

Preparing Patients With Myelodysplastic Syndrome for Transplant When Is Pre-transplant Cytoreductive Therapy Appropriate?

To date, the only treatment option with curative potential for patients suffering from myelodysplastic syndromes (MDS) is allogeneic stem cell transplantation (allo-SCT). However, patient selection for this procedure as well as the choice of the appropriate pre-transplant regime remain challenging. This review discusses both intensive chemotherapy and hypomethylating agents (HMAs) as debulking strategies. Current evidence on the use of AML-like intense chemotherapy suggests that this represents a valuable option especially in fitter and younger MDS patients with aggressive disease, whereas HMAs seem especially indicated in patients presenting with certain mutations and less proliferative disease in order to bridge them to transplant. The actual need for pre-transplant cytoreduction strongly depends on donor availability and disease progression: upfront allo-SCT might be considered for patients with slowly progressing MDS if a donor is readily available. Common to the data discussed in this review is their retrospective nature, making clear recommendations in terms of debulking strategy difficult. Prospective randomized trials are required to explicitly answer this question in the future.

New therapeutic approaches in myelodysplastic syndromes: Hypomethylating agents and lenalidomide

Recent advances in the treatment of myelodysplastic syndromes have come from the use of the hypomethylating agents decitabine and azacitidine as well as the immunomodulatory drug lenalidomide. Their clinical benefit has been demonstrated by randomized phase III clinical trials, mostly in high-risk and del(5q) myelodysplastic syndromes, respectively. Neither drug, however, appears to eradicate myelodysplastic stem cells, and thus they currently do not represent curative options. Here, we review data from both clinical and translational research on those drugs to identify their molecular and cellular mechanisms of action and to delineate paths for improved treatment allocation and further therapeutic advances in myelodysplastic syndromes.