A simple, robust, validated and highly predictive index for the determination of risk-directed therapy in acute myeloid leukaemia derived from the MRC AML 10 trial. United Kingdom Medical Research Council's Adult and Childhood Leukaemia Working Parties

Fludarabine, Cytarabine, Granulocyte Colony-Stimulating Factor, and Idarubicin With Gemtuzumab Ozogamicin Improves Event-Free Survival in Younger Patients With Newly Diagnosed AML and Overall Survival in Patients With NPM1 and FLT3 Mutations

PURPOSE

To determine the optimal induction chemotherapy regimen for younger adults with newly diagnosed AML without known adverse risk cytogenetics.

PATIENTS AND METHODS

One thousand thirty-three patients were randomly assigned to intensified (fludarabine, cytarabine, granulocyte colony-stimulating factor, and idarubicin [FLAG-Ida]) or standard (daunorubicin and Ara-C [DA]) induction chemotherapy, with one or two doses of gemtuzumab ozogamicin (GO). The primary end point was overall survival (OS).

RESULTS

There was no difference in remission rate after two courses between FLAG-Ida + GO and DA + GO (complete remission [CR] + CR with incomplete hematologic recovery 93% v 91%) or in day 60 mortality (4.3% v 4.6%). There was no difference in OS (66% v 63%; P = .41); however, the risk of relapse was lower with FLAG-Ida + GO (24% v 41%; P < .001) and 3-year event-free survival was higher (57% v 45%; P < .001). In patients with an NPM1 mutation (30%), 3-year OS was significantly higher with FLAG-Ida + GO (82% v 64%; P = .005). NPM1 measurable residual disease (MRD) clearance was also greater, with 88% versus 77% becoming MRD-negative in peripheral blood after cycle 2 (P = .02). Three-year OS was also higher in patients with a FLT3 mutation (64% v 54%; P = .047). Fewer transplants were performed in patients receiving FLAG-Ida + GO (238 v 278; P = .02). There was no difference in outcome according to the number of GO doses, although NPM1 MRD clearance was higher with two doses in the DA arm. Patients with core binding factor AML treated with DA and one dose of GO had a 3-year OS of 96% with no survival benefit from FLAG-Ida + GO.

CONCLUSION

Overall, FLAG-Ida + GO significantly reduced relapse without improving OS. However, exploratory analyses show that patients with NPM1 and FLT3 mutations had substantial improvements in OS. By contrast, in patients with core binding factor AML, outcomes were excellent with DA + GO with no FLAG-Ida benefit.

Vacuolar ATPase Is a Possible Therapeutic Target in Acute Myeloid Leukemia: Focus on Patient Heterogeneity and Treatment Toxicity

Vacuolar ATPase (V-ATPase) is regarded as a possible target in cancer treatment. It is expressed in primary acute myeloid leukemia cells (AML), but the expression varies between patients and is highest for patients with a favorable prognosis after intensive chemotherapy. We therefore investigated the functional effects of two V-ATPase inhibitors (bafilomycin A1, concanamycin A) for primary AML cells derived from 80 consecutive patients. The V-ATPase inhibitors showed dose-dependent antiproliferative and proapoptotic effects that varied considerably between patients. A proteomic comparison of primary AML cells showing weak versus strong antiproliferative effects of V-ATPase inhibition showed a differential expression of proteins involved in intracellular transport/cytoskeleton functions, and an equivalent phosphoproteomic comparison showed a differential expression of proteins that regulate RNA processing/function together with increased activity of casein kinase 2. Patients with secondary AML, i.e., a heterogeneous subset with generally adverse prognosis and previous cytotoxic therapy, myeloproliferative neoplasia or myelodysplastic syndrome, were characterized by a strong antiproliferative effect of V-ATPase inhibition and also by a specific mRNA expression profile of V-ATPase interactome proteins. Furthermore, the V-ATPase inhibition altered the constitutive extracellular release of several soluble mediators (e.g., chemokines, interleukins, proteases, protease inhibitors), and increased mediator levels in the presence of AML-supporting bone marrow mesenchymal stem cells was then observed, especially for patients with secondary AML. Finally, animal studies suggested that the V-ATPase inhibitor bafilomycin had limited toxicity, even when combined with cytarabine. To conclude, V-ATPase inhibition has antileukemic effects in AML, but this effect varies between patients.

Risk-Stratified Therapy for Pediatric Acute Myeloid Leukemia

Acute Myeloid Leukemia (AML) is the second most common type of leukemia in children. Recent advances in high-resolution genomic profiling techniques have uncovered the mutational landscape of pediatric AML as distinct from adult AML. Overall survival rates of children with AML have dramatically improved in the past 40 years, currently reaching 70% to 80% in developed countries. This was accomplished by the intensification of conventional chemotherapy, improvement in risk stratification using leukemia-specific cytogenetics/molecular genetics and measurable residual disease, appropriate use of allogeneic hematopoietic stem cell transplantation, and improvement in supportive care. However, the principle therapeutic approach for pediatric AML has not changed substantially for decades and improvement in event-free survival is rather modest. Further refinements in risk stratification and the introduction of emerging novel therapies to contemporary therapy, through international collaboration, would be key solutions for further improvements in outcomes.

NK cell defects: implication in acute myeloid leukemia

Acute Myeloid Leukemia (AML) is a complex disease with rapid progression and poor/unsatisfactory outcomes. In the past few years, the focus has been on developing newer therapies for AML; however, relapse remains a significant problem. Natural Killer cells have strong anti-tumor potential against AML. This NK-mediated cytotoxicity is often restricted by cellular defects caused by disease-associated mechanisms, which can lead to disease progression. A stark feature of AML is the low/no expression of the cognate HLA ligands for the activating KIR receptors, due to which these tumor cells evade NK-mediated lysis. Recently, different Natural Killer cell therapies have been implicated in treating AML, such as the adoptive NK cell transfer, Chimeric antigen receptor-modified NK (CAR-NK) cell therapy, antibodies, cytokine, and drug treatment. However, the data available is scarce, and the outcomes vary between different transplant settings and different types of leukemia. Moreover, remission achieved by some of these therapies is only for a short time. In this mini-review, we will discuss the role of NK cell defects in AML progression, particularly the expression of different cell surface markers, the available NK cell therapies, and the results from various preclinical and clinical trials.

Impact of pre-transplant induction and consolidation cycles on AML allogeneic transplant outcomes: a CIBMTR analysis in 3113 AML patients

We investigated the impact of the number of induction/consolidation cycles on outcomes of 3113 adult AML patients who received allogeneic hematopoietic cell transplantation (allo-HCT) between 2008 and 2019. Patients received allo-HCT using myeloablative (MAC) or reduced-intensity (RIC) conditioning in first complete remission (CR) or with primary induction failure (PIF). Patients who received MAC allo-HCT in CR after 1 induction cycle had 1.3-fold better overall survival (OS) than 2 cycles to CR and 1.47-fold better than ≥3 cycles. OS after CR in 2 or ≥3 cycles was similar. Relapse risk was 1.65-fold greater in patients receiving ≥3 cycles to achieve CR. After RIC allo-HCT, the number of induction cycles to CR did not affect OS. Compared to CR in 1 cycle, relapse risk was 1.24-1.41-fold greater in patients receiving 2 or ≥3 cycles. For patients receiving only 1 cycle to CR, consolidation therapy prior to MAC allo-HCT was associated with improved OS vs. no consolidation therapy. Detectable MRD at the time of MAC allo-HCT did not impact outcomes while detectable MRD preceding RIC allo-HCT was associated with an increased risk of relapse. For allo-HCT in PIF, OS was significantly worse than allo-HCT in CR after 1-3 cycles.

Efficacy of conventional-dose cytarabine, idarubicin and thioguanine versus intermediate-dose cytarabine and idarubicin in the induction treatment of acute myeloid leukemia: Long-term results of the prospective randomized nationwide AML-2003 study by the Finnish Leukemia Group

OBJECTIVES

AML-2003 study sought to compare the long-term efficacy and safety of IAT and IdAraC-Ida in induction chemotherapy of acute myeloid leukemia (AML) and introduce the results of an integrated genetic and clinical risk classification guided treatment strategy.

METHODS

Patients were randomized to receive either IAT or IdAraC-Ida as the first induction treatment. Intensified postremission strategies were employed based on measurable residual disease (MRD) and risk classification. Structured questionnaire forms were used to gather data prospectively.

RESULTS

A total of 356 AML patients with a median age of 53 years participated in the study. Long-term overall survival (OS) and relapse-free survival (RFS) were both 49% at 10 years. The median follow-up was 114 months. No significant difference in remission rate, OS or RFS was observed between the two induction treatments. Risk classification according to the protocol, MRD after the first and the last consolidation treatment affected the OS and RFS significantly (p < .001).

CONCLUSIONS

Intensified cytarabine dose in the first induction treatment was not better than IAT in patients with AML. Intensification of postremission treatment in patients with clinical risk factors or MRD seems reasonable, but randomized controlled studies are warranted in the future.

Acute Myeloid Leukemia Patients Requiring Two Cycles of Intensive Induction for Attainment of Remission Experience Inferior Survival Compared with Patients Requiring a Single Course of Induction Chemotherapy

BACKGROUND

Achievement of initial remission remains the most important clinical factor predicting long term survival in acute myeloid leukemia (AML) patients treated with intensive chemotherapy. Yet, whether the patient subset in need of a second cycle of intensive induction chemotherapy to reach remission experiences inferior outcomes compared to patients reaching remission after a single cycle of therapy, remains uncertain.

PATIENTS AND METHODS

Retrospective analysis of 302 consecutive AML patients treated with intensive induction chemotherapy in our institution in 2007-2020.

RESULTS

Median patient age was 55 years with a median follow-up duration of 23 months. In terms of European LeukemiaNet (ELN) 2017 classification, 122 patients (40%) were designated as favorable risk disease, 108 patients (36%) were intermediate risk, and 71 patients (24%) were adverse risk. A hundred and seventy-seven patients (60%) attained remission following initial chemotherapy while 58 patients (20%) required an additional cycle of intensive chemotherapy for remission. Patients requiring 2 cycles to reach remission were less likely to be NPM1 mutated (33% versus 51%; P=.025) or be in the ELN 2017 favorable risk category (25% versus 57%; P<.001). In multivariate analysis achievement of remission following 2 cycles of intensive compared with a single cycle resulted in significantly inferior survival [hazard ratio (HR)=1.67, 95% CI, 1.07-2.59; P=.025] whereas leukemia-free survival was not significantly impacted (HR=1.26, 95% CI, 0.85-1.85) (P=.23). Relapse rates also did not differ to a significant degree between groups (45% versus 47%, P=.8).

CONCLUSION

Attainment of an early remission significantly impacts long term survival in AML patients.

Receptor Activator of NF-κB (RANK) Confers Resistance to Chemotherapy in AML and Associates with Dismal Disease Course

Simple Summary

Acute myeloid leukemia (AML) is the most common form of acute leukemia in adults. Despite the emergence of new therapeutic agents in recent years, curation remains challenging, and new and better treatment options are needed. In the present study, we investigated the expression, prognostic significance, and functional role of the Receptor Activator of Nuclear Factor-κB (RANK) in AML. We found that RANK is expressed on leukemic cells in a substantial proportion of AML patients and is associated with a dismal disease course. We further demonstrated that signaling via RANK induces release of factors that favor AML cell survival and confers resistance to chemotherapeutics in AML treatment. Together, our findings identify RANK as novel prognostic marker and putative candidate for therapeutic intervention in AML to enhance response to treatment.

Abstract

Although treatment options of acute myeloid leukemia (AML) have improved over the recent years, prognosis remains poor. Better understanding of the molecular mechanisms influencing and predicting treatment efficacy may improve disease control and outcome. Here we studied the expression, prognostic relevance and functional role of the tumor necrosis factor receptor (TNFR) family member Receptor Activator of Nuclear Factor (NF)-κB (RANK) in AML. We conducted an experimental ex vivo study using leukemic cells of 54 AML patients. Substantial surface expression of RANK was detected on primary AML cells in 35% of the analyzed patients. We further found that RANK signaling induced the release of cytokines acting as growth and survival factors for the leukemic cells and mediated resistance of AML cells to treatment with doxorubicin and cytarabine, the most commonly used cytostatic compounds in AML treatment. In line, RANK expression correlated with a dismal disease course as revealed by reduced overall survival. Together, our results show that RANK plays a yet unrecognized role in AML pathophysiology and resistance to treatment, and identify RANK as “functional” prognostic marker in AML. Therapeutic modulation of RANK holds promise to improve treatment response in AML patients.

Outcomes of intensification of induction chemotherapy for children with high-risk acute myeloid leukemia: A report from the Children's Oncology Group

BACKGROUND

High-risk pediatric acute myeloid leukemia confers a poor prognosis, and alternative strategies are needed to improve outcomes. We hypothesized that intensifying induction on the AAML1031 clinical trial would improve outcomes compared to the predecessor trial AAML0531.

METHODS

Patients on AAML0531 received cytarabine (1600 mg/m² )/daunorubicin (150 mg/m² )/etoposide (ADE) for induction II and patients on AAML1031 received mitoxantrone (48 mg/m² )/cytarabine (8000 mg/m² ) (MA). Stem cell transplant (SCT) conditioning included busulfan/cyclophosphamide on AAML0531, whereas AAML1031 used busulfan/fludarabine and liberalized donor eligibility. Patients were included in this analysis if they met high-risk criteria common to the two trials by cytogenics or poor disease response after induction I ADE.

RESULTS

MA provided no benefit over ADE at: induction II response (complete response [CR]: 64% vs. 62%, p = .87; measurable residual disease [MRD]+: 57% vs. 46%, p = .34); or intensification I response (CR: 79% vs. 94%, p = .27; MRD+: 27% vs. 20%, p = 1.0). When considered with altered SCT approach, MA did not improve 5-year disease-free survival (24% ± 9% vs. 18% ± 15%, p = .63) or 5-year overall survival (35% ± 10% vs. 38% ± 18%, p = .66). MA was associated with slower neutrophil recovery (median 34 vs. 27 days, p = .007) and platelet recovery (median 29 vs. 24.5 days, p = .04) and longer hospital stay (32 vs. 28 days, p = .01) during induction II.

CONCLUSION

Intensification of induction II did not improve treatment response or survival, but did increase toxicity and resource utilization. Alternative strategies are urgently needed to improve outcomes for pediatric patients with high-risk acute myeloid leukemia (trials registered at clinicaltrials.gov NCT01371981, NCT00372593).

Patient Heterogeneity in Acute Myeloid Leukemia: Leukemic Cell Communication by Release of Soluble Mediators and Its Effects on Mesenchymal Stem Cells

Acute myeloid leukemia (AML) is an aggressive bone marrow malignancy, and non-leukemic stromal cells (including mesenchymal stem cells, MSCs) are involved in leukemogenesis and show AML-supporting effects. We investigated how constitutive extracellular mediator release by primary human AML cells alters proteomic profiles of normal bone marrow MSCs. An average of 6814 proteins (range 6493−6918 proteins) were quantified for 41 MSC cultures supplemented with AML-cell conditioned medium, whereas an average of 6715 proteins (range 6703−6722) were quantified for untreated control MSCs. The AML effect on global MSC proteomic profiles varied between patients. Hierarchical clustering analysis identified 10 patients (5/10 secondary AML) showing more extensive AML-effects on the MSC proteome, whereas the other 31 patients clustered together with the untreated control MSCs and showed less extensive AML-induced effects. These two patient subsets differed especially with regard to MSC levels of extracellular matrix and mitochondrial/metabolic regulatory proteins. Less than 10% of MSC proteins were significantly altered by the exposure to AML-conditioned media; 301 proteins could only be quantified after exposure to conditioned medium and 201 additional proteins were significantly altered compared with the levels in control samples (153 increased, 48 decreased). The AML-modulated MSC proteins formed several interacting networks mainly reflecting intracellular organellar structure/trafficking but also extracellular matrix/cytokine signaling, and a single small network reflecting altered DNA replication. Our results suggest that targeting of intracellular trafficking and/or intercellular communication is a possible therapeutic strategy in AML.

The long shadow of socioeconomic deprivation over the modern management of acute myeloid leukemia: time to unravel the challenges

Biological and non-biological variables unrelated to acute myeloid leukemia (AML) preclude standard therapy in many settings, with "real world" patients under-represented in clinical trials and prognostic models. Here, using a case-based format, we illustrate the impact that socioeconomic and anthropogeographical constraints can have on optimally managing AML in 4 different healthcare systems. The granular details provided, emphasize the need for the development and targeting of socioeconomic interventions that are commensurate with the changing landscape of AML therapeutics, in order to avoid worsening the disparity in outcomes between patients with biologically similar disease.

AMELIORATE: early intensification in FLT3-mutated acute myeloid leukemia based on peripheral blast clearance - MYNERVA-GIMEMA AML1919 trial

AMELIORATE is a Phase III, randomized trial aiming to personalize treatment intensity in FLT3-mutated acute myeloid leukemia. The current study provides an early appraisal of chemosensitivity based on peripheral blasts clearance, as assessed by multiparameter flow cytometry, from baseline to day 4 of induction. This biomarker was previously demonstrated to predict complete remission achievement and measurable residual disease status. For patients experiencing low peripheral blast cells (i.e., ≤2.0 logs), two major adjustments of treatment as compared with current standard of care are envisioned in the experimental arm: the immediate switch to intensified induction with high-doses cytarabine (1500 mg/m² b.i.d. on days 5-7 of induction); and the early allocation of the patient to high-risk disease category, to be further refined later based on postinduction measurable residual disease status.

Allogeneic Stem Cell Transplantation for Acute Myeloid Leukemia: Who, When, and How?

Although the majority of patients with acute myeloid leukemia (AML) treated with intensive chemotherapy achieve a complete remission (CR), many are destined to relapse if treated with intensive chemotherapy alone. Allogeneic stem cell transplant (allo-SCT) represents a pivotally important treatment strategy in fit adults with AML because of its augmented anti-leukemic activity consequent upon dose intensification and the genesis of a potent graft-versus-leukemia effect. Increased donor availability coupled with the advent of reduced intensity conditioning (RIC) regimens has dramatically increased transplant access and consequently allo-SCT is now a key component of the treatment algorithm in both patients with AML in first CR (CR1) and advanced disease. Although transplant related mortality has fallen steadily over recent decades there has been no real progress in reducing the risk of disease relapse which remains the major cause of transplant failure and represents a major area of unmet need. A number of therapeutic approaches with the potential to reduce disease relapse, including advances in induction chemotherapy, the development of novel conditioning regimens and the emergence of the concept of post-transplant maintenance, are currently under development. Furthermore, the use of genetics and measurable residual disease technology in disease assessment has improved the identification of patients who are likely to benefit from an allo-SCT which now represents an increasingly personalized therapy. Future progress in optimizing transplant outcome will be dependent on the successful delivery by the international transplant community of randomized prospective clinical trials which permit examination of current and future transplant therapies with the same degree of rigor as is routinely adopted for non-transplant therapies.

The Constitutive Extracellular Protein Release by Acute Myeloid Leukemia Cells-A Proteomic Study of Patient Heterogeneity and Its Modulation by Mesenchymal Stromal Cells

Simple Summary

The formation of normal blood cells in the bone marrow is supported by a network of non-hematopoietic cells including connective tissue cells, blood vessel cells and bone-forming cells. These cell types support and regulate the growth of acute myeloid leukemia (AML) cells and communicate with leukemic cells through the release of proteins to their common extracellular microenvironment. One of the AML-supporting normal cell types is a subset of connective tissue cells called mesenchymal stem cells. In the present study, we observed that AML cells release a wide range of diverse proteins into their microenvironment, but patients differ both with regard to the number and amount of released proteins. Inhibition of this bidirectional communication through protein release between AML cells and leukemia-supporting normal cells may become a new strategy for cancer treatment.

Abstract

Extracellular protein release is important both for the formation of extracellular matrix and for communication between cells. We investigated the extracellular protein release by in vitro cultured normal mesenchymal stem cells (MSCs) and by primary human acute myeloid leukemia (AML) cells derived from 40 consecutive patients. We observed quantifiable levels of 3082 proteins in our study; for the MSCs, we detected 1446 proteins, whereas the number of released proteins for the AML cells showed wide variation between patients (average number 1699, range 557–2380). The proteins were derived from various cellular compartments (e.g., cell membrane, nucleus, and cytoplasms), several organelles (e.g., cytoskeleton, endoplasmatic reticulum, Golgi apparatus, and mitochondria) and had various functions (e.g., extracellular matrix and exosomal proteins, cytokines, soluble adhesion molecules, protein synthesis, post-transcriptional modulation, RNA binding, and ribonuclear proteins). Thus, AML patients were very heterogeneous both regarding the number of proteins and the nature of their extracellularly released proteins. The protein release profiles of MSCs and primary AML cells show a considerable overlap, but a minority of the proteins are released only or mainly by the MSC, including several extracellular matrix molecules. Taken together, our observations suggest that the protein profile of the extracellular bone marrow microenvironment differs between AML patients, these differences are mainly caused by the protein release by the leukemic cells but this leukemia-associated heterogeneity of the overall extracellular protein profile is modulated by the constitutive protein release by normal MSCs.

The complete story of less than complete responses: The evolution and application of acute myeloid leukemia clinical responses

Complete remission (CR) has long been the critical therapeutic response in acute myeloid leukemia (AML). However, "less than CR" responses have been and continue to be proposed to define clinically meaningful post-therapy outcomes. These responses include CR with incomplete recovery (CRi), CR with incomplete platelet recovery (CRp) and, most recently, CR with partial hematologic recovery (CRh), which has been introduced and subsequently used for regulatory approval. However, the clinical benefits associated with "less than CR" responses have primarily been evaluated in the context of intensive therapies. In an era with sophisticated measurable residual disease (MRD) assessments, including flow-based, cytogenetic and molecular techniques, and an increase in "targeted", non-intensive therapies, the clinical value of responses that are "less than CR" must be reevaluated. Improvements in the rate of CR has not always led to improvements in OS among older patients. As such, MRD techniques might help define a more stringent response criterion (MRD-negative CR) that might better correlate with OS and should be incorporated in future clinical trials. Here we discuss the evolution of CR and "less than CR" responses, data regarding their clinical benefits, and considerations relevant to response assessments with newer therapies.

Biological characteristics of aging in human acute myeloid leukemia cells: the possible importance of aldehyde dehydrogenase, the cytoskeleton and altered transcriptional regulation

Patients with acute myeloid leukemia (AML) have a median age of 65-70 years at diagnosis. Elderly patients have more chemoresistant disease, and this is partly due to decreased frequencies of favorable and increased frequencies of adverse genetic abnormalities. However, aging-dependent differences may also contribute. We therefore compared AML cell proteomic and phosphoproteomic profiles for (i) elderly low-risk and younger low-risk patients with favorable genetic abnormalities; and (ii) high-risk patients with adverse genetic abnormalities and a higher median age against all low-risk patients with lower median age. Elderly low-risk and younger low-risk patients showed mainly phosphoproteomic differences especially involving transcriptional regulators and cytoskeleton. When comparing high-risk and low-risk patients both proteomic and phosphoproteomic studies showed differences involving cytoskeleton and immunoregulation but also transcriptional regulation and cell division. The age-associated prognostic impact of cyclin-dependent kinases was dependent on the cellular context. The protein level of the adverse prognostic biomarker mitochondrial aldehyde dehydrogenase (ALDH2) showed a similar significant upregulation both in elderly low-risk and elderly high-risk patients. Our results suggest that molecular mechanisms associated with cellular aging influence chemoresistance of AML cells, and especially the cytoskeleton function may then influence cellular hallmarks of aging, e.g. mitosis, polarity, intracellular transport and adhesion.

The Implementation of Mass Spectrometry-Based Proteomics Workflows in Clinical Routines of Acute Myeloid Leukemia: Applicability and Perspectives

With the current reproducibility of proteome preparation workflows along with the speed and sensitivity of the mass spectrometers, the transition of the mass spectrometry (MS)-based proteomics technology from biomarker discovery to clinical implementation is under appraisal in the biomedicine community. Therefore, this technology might be implemented soon to detect well-known biomarkers in cancers and other diseases. Acute myeloid leukemia (AML) is an aggressive heterogeneous malignancy that requires intensive treatment to cure the patient. Leukemia relapse is still a major challenge even for patients who have favorable genetic abnormalities. MS-based proteomics could be of great help to both describe the proteome changes of individual patients and identify biomarkers that might encourage specific treatments or clinical strategies. Herein, we will review the advances and availability of the MS-based proteomics strategies that could already be used in clinical proteomics. However, the heterogeneity of complex diseases as AML requires consensus to recognize AML biomarkers and to establish MS-based workflows that allow their unbiased identification and quantification. Although our literature review appears promising towards the utilization of MS-based proteomics in clinical AML in a near future, major efforts are required to validate AML biomarkers and agree on clinically approved workflows.

Prognostic value of platelet recovery degree before and after achieving minimal residual disease negative complete remission in acute myeloid leukemia patients

Background

Risk stratification and prognosis prediction of acute myeloid leukemia (AML) are largely dependent on pre-treatment information. However, post-treatment data also provides much useful information. In this retrospective study, we explored whether the level of blood count recovery before and after the first minimal residual disease (MRD) negative complete remission (CR) is relevant to clinical outcomes of AML patients.

Methods

For each included patient, peripheral platelet counts were measured on the day before initial treatment (PLT_pre), whereas platelet peak values (PLT_peak) were recorded after marrow recovery following the chemotherapy course inducing the first MRD-negative CR. The difference (D_PLT) between these two values (D_PLT = PLT_peak−PLT_pre) was calculated. X-tile software was utilized to establish the optimal cut-point for D_PLT, which was expected to distinguish CR patients with different clinical outcomes. A cross validation analysis was conducted to confirm the robustness of the established cut-point. The results were further tested by a Cox multivariate analysis.

Results

The optimal cut-point of D_PLT was determined as 212 × 10⁹/L. Patients in high D_PLT group were observed to have a significantly better PFS (p = 0.016) and a better OS (without statistical significance, p = 0.106). Cox multivariate analysis showed that higher D_PLT was associated with longer PFS (HR = 2.894, 95% CI: 1.320–6.345, p = 0.008) and longer OS (HR = 3.077, 95% CI: 1.130–8.376, p = 0.028).

Conclusion

Platelet recovery degree before and after achieving MRD-negative CR (D_PLT) is a potential predictor of clinical outcomes in CR patients. Higher D_PLT value is associated with longer PFS and OS. Our findings may help to develop simple methods for AML prognosis evaluation.

Survival differences and associated molecular signatures of DNMT3A-mutant acute myeloid leukemia patients

Acute myeloid leukemia (AML) is a very heterogeneous and highly malignant blood cancer. Mutations of the DNA methyltransferase DNMT3A are among the most frequent recurrent genetic lesions in AML. The majority of DNMT3A-mutant AML patients shows fast relapse and poor survival, but also patients with long survival or long-term remission have been reported. Underlying molecular signatures and mechanisms that contribute to these survival differences are only poorly understood and have not been studied in detail so far. We applied hierarchical clustering to somatic gene mutation profiles of 51 DNMT3A-mutant patients from The Cancer Genome Atlas (TCGA) AML cohort revealing two robust patient subgroups with profound differences in survival. We further determined molecular signatures that distinguish both subgroups. Our results suggest that FLT3 and/or NPM1 mutations contribute to survival differences of DNMT3A-mutant patients. We observed an upregulation of genes of the p53, VEGF and DNA replication pathway and a downregulation of genes of the PI3K-Akt pathway in short- compared to long-lived patients. We identified that the majority of measured miRNAs was downregulated in the short-lived group and we found differentially expressed microRNAs between both subgroups that have not been reported for AML so far (miR-153-2, miR-3065, miR-95, miR-6718) suggesting that miRNAs could be important for prognosis. In addition, we learned gene regulatory networks to predict potential major regulators and found several genes and miRNAs with known roles in AML pathogenesis, but also interesting novel candidates involved in the regulation of hematopoiesis, cell cycle, cell differentiation, and immunity that may contribute to the observed survival differences of both subgroups and could therefore be important for prognosis. Moreover, the characteristic gene mutation and expression signatures that distinguished short- from long-lived patients were also predictive for independent DNMT3A-mutant AML patients from other cohorts and could also contribute to further improve the European LeukemiaNet (ELN) prognostic scoring system. Our study represents the first in-depth computational approach to identify molecular factors associated with survival differences of DNMT3A-mutant AML patients and could trigger additional studies to develop robust molecular markers for a better stratification of AML patients with DNMT3A mutations.

Randomized trial comparing standard vs sequential high-dose chemotherapy for inducing early CR in adult AML

Here we evaluated whether sequential high-dose chemotherapy (sHD) increased the early complete remission (CR) rate in acute myelogenous leukemia (AML) compared with standard-intensity idarubicin-cytarabine-etoposide (ICE) chemotherapy. This study enrolled 574 patients (age, 16-73 years; median, 52 years) who were randomly assigned to ICE (n = 286 evaluable) or sHD (2 weekly 3-day blocks with cytarabine 2 g/m² twice a day for 2 days plus idarubicin; n = 286 evaluable). Responsive patients were risk-stratified for a second randomization. Standard-risk patients received autograft or repetitive blood stem cell-supported high-dose courses. High-risk patients (and standard-risk patients not mobilizing stem cells) underwent allotransplantation. CR rates after 2 induction courses were comparable between ICE (80.8%) and sHD (83.6%; P = .38). sHD yielded a higher single-induction CR rate (69.2% vs 81.5%; P = .0007) with lower resistance risk (P < .0001), comparable mortality (P = .39), and improved 5-year overall survival (39% vs 49%; P = .045) and relapse-free survival (36% vs 48%; P = .028), despite greater hematotoxicity delaying or reducing consolidation blocks. sHD improved the early CR rate in high-risk AML (odds ratio, 0.48; 95% confidence interval [CI], 0.31-0.74; P = .0008) and in patients aged 60 years and less with de novo AML (odds ratio, 0.46; 95% CI, 0.27-0.78; P = .003), and also improved overall/relapse-free survival in the latter group (hazard ratio, 0.70; 95% CI, 0.52-0.94; P = .01), in standard-risk AML, and postallograft (hazard ratio, 0.61; 95% CI, 0.39-0.96; P = .03). sHD was feasible, effectively achieved rapid CR, and improved outcomes in AML subsets. This study is registered at www.clinicaltrials.gov as #NCT00495287.

Prognostic Factors in Childhood Acute Myeloid Leukemia; Experience from A Developing Country

BACKGROUND

In the developed world, 5-years survival of childhood acute myeloid leukaemia (AML) has improved to 70%. However, the survival rates in the developing world are below 40%. The main contributing factors to these reduced survival rates are a late presentation, malnutrition and high treatment-related mortality.

AIM

To document the factors affecting treatment outcome of childhood AML at a tertiary care facility of Pakistan.

METHODS AND RESULTS

All newly registered cases of AML under 18 years of age from January 1, 2012 onwards who completed their treatment before November 30, 2019 were included. Data of 219 cases of AML containing 140 (63.9%) males and 79 (36.1%) females was analyzed. The mean age was 6.30 ± 3.66 years. Pallor was the commonest presenting features in 180 (82.2%) and M2 was the commonest French American-British (FAB) subtype in 103 (47.0%) cases. In univariate analysis, high white blood cells (WBC) count at presentation (P = .006), poor nutritional status (P = .005), unfavourable cytogenetics (P = .019), certain types of FAB AML subtype (P = .005), and use of etoposide in induction chemotherapy (P = .042) significantly adversely affected overall survival (OS). Neutropenic sepsis and bleeding were the major causes of treatment-related mortality. Response to induction chemotherapy was the most significant prognostic factor in the multivariate analysis (P = <.001). After a median follow-up of 40.96 ± 26.23 months, 5-year OS and DFS of the cohort were 40.6% and 38.3% respectively.

CONCLUSIONS

In this largest cohort of childhood AML from Pakistan, high WBC count at presentation, malnutrition, unfavourable cytogenetics and use of etoposide during induction chemotherapy were associated with decreased OS and DFS rates. Response to the induction chemotherapy was the most significant prognostic factor.

Proteome and Phosphoproteome Changes Associated with Prognosis in Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a hematological cancer that mainly affects the elderly. Although complete remission (CR) is achieved for the majority of the patients after induction and consolidation therapies, nearly two-thirds relapse within a short interval. Understanding biological factors that determine relapse has become of major clinical interest in AML. We utilized liquid chromatography tandem mass spectrometry (LC-MS/MS) to identify the protein changes and protein phosphorylation events associated with AML relapse in primary cells from 41 AML patients at time of diagnosis. Patients were defined as relapse-free if they had not relapsed within a five-year clinical follow-up after AML diagnosis. Relapse was associated with increased expression of RNA processing proteins and decreased expression of V-ATPase proteins. We also observed an increase in phosphorylation events catalyzed by cyclin-dependent kinases (CDKs) and casein kinase 2 (CSK2). The biological relevance of the proteome findings was supported by cell proliferation assays using inhibitors of V-ATPase (bafilomycin), CSK2 (CX-4945), CDK4/6 (abemaciclib) and CDK2/7/9 (SNS-032). While bafilomycin preferentially inhibited the cells from relapse patients, the kinase inhibitors were less efficient in these cells. This suggests that therapy against the upregulated kinases could also target the factors inducing their upregulation rather than their activity. This study, therefore, presents markers that could help predict AML relapse and direct therapeutic strategies.

Pediatric acute myeloid leukemia: updates on biology, risk stratification, and therapy

PURPOSE OF REVIEW

Despite advances in therapy over the past decades, overall survival for children with acute myeloid leukemia (AML) has not exceeded 70%. In this review, we highlight recent insights into risk stratification for patients with pediatric AML and discuss data driving current and developing therapeutic approaches.

RECENT FINDINGS

Advances in cytogenetics and molecular profiling, as well as improvements in detection of minimal residual disease after induction therapy, have informed risk stratification, which now relies heavily on these elements. The treatment of childhood AML continues to be based primarily on intensive, conventional chemotherapy. However, recent trials focus on limiting treatment-related toxicity through the identification of low-risk subsets who can safely receive fewer cycles of chemotherapy, allocation of hematopoietic stem-cell transplant to only high-risk patients and optimization of infectious and cardioprotective supportive care.

SUMMARY

Further incorporation of genomic and molecular data in pediatric AML will allow for additional refinements in risk stratification to enable the tailoring of treatment intensity. These data will also dictate the incorporation of molecularly targeted therapeutics into frontline treatment in the hope of improving survival while decreasing treatment-related toxicity.

Update on management and progress of novel therapeutics for R/R AML: an Iberian expert panel consensus

A significant proportion of adult patients with acute myeloid leukemia (AML) fail to achieve complete remission or will relapse later on after achieving it. Prognosis for relapsed or refractory (R/R) AML patients remains discouraging, with the main curative option still relying on hematopoietic stem cell transplant (HSCT) for those who are eligible. Beyond morphological bone marrow and peripheral blood assessment, evaluation of patient performance status and comorbidities, as well as genetic/molecular characterization, is crucial to make an accurate diagnosis and prognosis, which will be useful to select the most appropriate treatment. Emerging strategies are mainly focusing on the development of immune- and molecular-based approaches. Novel targeted therapies are generally well tolerated, potentially allowing them to be administered alone or in combination with classical chemotherapy agents. Enrolment in clinical trials should be considered first option for R/R AML patients, either as a bridge to HSCT or to benefit from novel therapies that eventually may prolong survival and improve quality of life. An Iberian expert panel has reviewed the recent advances in the management of R/R AML with the aim to develop updated evidence and expert opinion-based recommendations.

EZH2, new diagnosis and prognosis marker in acute myeloid leukemia patients

PURPOSE

Acute myeloid leukemia (AML) is a heterogeneous disease. The discovery of novel discriminative biomarkers remains of utmost value for improving outcome predictions. Enhancer of zeste homolog 2 (EZH2) is a histone methyltransferase of H3K27me3. It is frequently up-regulated in human cancers and associated with silencing of differentiation genes. We aimed herein to investigate the prevalence and prognosis impact of somatic EZH2 mutations and their potential associations with other prognostic markers FLT3, NPM1, DNMT3A and IDH2.

MATERIALS AND METHODS

Our study population was composed of 211 Tunisian patients with de novo AML and 14 healthy donors. The 11 last exons coding the set domain of EZH2 were investigated by PCR and Sanger sequencing.

RESULTS

EZH2 mutations were identified in 66/211 (31%) patients with a sex ratio of 1.06. The presence of EZH2 mutations was statistically significantly associated with failure consolidation therapy (p = 0.004). There were no differences in the incidence of EZH2 mutations and FLT3-ITD, NPM1, DNMT3A and IDH2 mutations. When EZH2 mutations were associated with those of FLT3 or IDH2, a short duration of progression free survival was observed (p < 0.05). Moreover, CD7 aberrant markers conferred a poor prognosis in EZH2 mutated patients (p < 0.05).

CONCLUSIONS

Given these data we conclude that EZH2 mutations are frequent in our patients, and can be used as a prognosis marker in combination with FLT3, IDH2 mutations and CD7 marker, to stratify AML patients and to guide therapeutic decisions.

Emerging agents and regimens for treatment of relapsed and refractory acute myeloid leukemia

Relapsed and refractory acute myeloid leukemia (R/R AML) has complicated pathogenesis. Its treatment is complicated, and the prognosis is poor. So far, there is no consensus on what is the optimal treatment strategy. With the deepening of research, new chemotherapy regimens, new small molecule inhibitors, and immunotherapy have been increasingly applied to clinical trials, providing more possibilities for the treatment of R/R AML. The most effective treatment for patients who achieve complete remission after recurrence is still sequential conditioning therapy followed by allogeneic hematopoietic cell transplantation. Finding the best combination of treatments is still an important goal for the future.

Optimal Measurable Residual Disease Testing for Acute Myeloid Leukemia

Increasing evidence supports the prognostic significance of measurable residual disease (MRD) in acute myeloid leukemia (AML). Dynamic MRD assessment for patients with AML complements baseline patient risk assessment factors in determining patient prognosis. MRD status may also be helpful in informing therapeutic decisions. The European Leukemia Net MRD working party recently issued consensus recommendations for the use of MRD in AML. The Food and Drug Administration also issued advice for using MRD in trials of hematologic malignancies. This article discusses MRD testing, highlights the challenges in adopting MRD testing in clinical practice, and provides insights into the future of the field.

The prognostic significance of the long non-coding RNAs "CCAT1, PVT1" in t(8;21) associated Acute Myeloid Leukemia

Long non-coding RNA (LncRNA) is recently linked to various types of cancers, CCAT and PVT1 are two LncRNAs linked to t(8;21) associated Acute Myeloid Leukemia, the interplay between CCAT, PVT1 and the MYC proto-oncogene implicated in t(8;21) could present an opportunity for using LncRNA as prognostic biomarker or a target for therapy, We investigated the expression levels of LncRNAs in 70 patients; 30 with t(8;21) positive AML and 40 with t(8;21) negative AML, We found that CCAT1 and PVT1 are expressed in higher levels in t(8;21) positive -AML by 5.3 folds compared to t(8;21) negative group; the expression values were significantly associated with high-risk clinical criteria; moreover, they are associated with lower overall survival (OS) rate and leukemia-free survival (LFS), however we didn't find a statistically significant cut-off value of LncRNAs using the Cox regression analysis for Lnc_PVT1 except with LFS, we conclude that high expression levels of CCAT1 and PVT1 are associated with poor prognosis while being poor prognostic biomarkers in t(8;21) associated AML.

Measurable residual disease testing for personalized treatment of acute myeloid leukemia

This review summarizes - with the practicing hematologist in mind - the methods used to determine measurable residual disease (MRD) in everyday practice with some future perspectives, and the current knowledge about the prognostic impact of MRD on outcome in acute myeloid leukemia (AML), excluding acute promyelocytic leukemia. Possible implications for choice of MRD method, timing of MRD monitoring, and guidance of therapy are discussed in general and in some detail for certain types of leukemia with specific molecular markers to monitor, including core binding factor (CBF)-leukemias and NPM1-mutated leukemias.

Rebound Thrombocytosis after Induction Chemotherapy is a Strong Biomarker for Favorable Outcome in AML Patients

Whereas the molecular events underlying acute myeloid leukemia (AML) are increasingly identified, dynamics of hematologic recovery following induction chemotherapy remain mysterious. Platelet recovery may vary between incomplete and excess recovery among patients achieving remission. We analyzed platelet recovery after the first induction cycle in 291 consecutive AML patients. We defined excess platelet rebound (EPR) as platelet increase above 500 G/L. We observed EPR in 120 (41.2%) patients. EPR+ patients had lower platelets at diagnosis, higher marrow infiltration, more frequently NPM1 mutations, and were associated with ELN favorable risk. Absence of EPR correlated with complex karyotypes, ELN intermediate-I and adverse risk, and therapy-related AML. Overall survival was better in EPR+ patients than EPR- (median 125 vs 41 months; p = 0.04), as was disease-free survival. By multivariate analysis, EPR+ was an independent parameter associated with favorable survival. Plasma thrombopoietin (TPO) levels at diagnosis indicated EPR+ (p < 0.0001), while GATA-1, GATA-2, and MPL mRNA expression did not differ between EPR+ and EPR- patients. Finally, transcription factors blocking early megakaryopoiesis were upregulated in EPR- patients, while NFE2 involved in late megakaryocyte differentiation was increased in EPR+ patients. Our work identifies mechanisms involved in platelet recovery after induction chemotherapy.

The emerging role of measurable residual disease detection in AML in morphologic remission

Despite the increasing knowledge of the genomic landscape of acute myeloid leukemia (AML), prediction merely based on genetics fails to anticipate outcome, presumably due to the heterogeneous composition of the leukemic clone determining complex interactions between different genetic abnormalities. Therefore, the introduction of a post-treatment biomarker exploring the quality of response to therapy such as assessment of measurable (previously minimal) residual disease (MRD) may lead to refinements of the prognostic assessment in AML. In this view, the European LeukemiaNet has recently endorsed the achievement of a MRD negative morphologic complete remission as a purpose the treatment. Techniques like multiparametric flow cytometry and reverse transcriptase-quantitative polymerase chain reaction have reached a level of sensitivity and specificity that make them ready for introduction in clinical practice. In the present review, we will give an update on the efforts in harmonization and/or standardization of MRD assessment in AML, focusing on the newest acquisitions in the clinical applications of MRD, and considering issues like relationship of MRD with leukemic stem cells or MRD assessment in peripheral blood.

Comparison of spatial chromosomal organization between bone marrow and peripheral blood in acute myeloid leukemia

Acute myeloid leukemia associated with t(8;21)(q22;q22)/runt related transcription factor (RUNX)1-RUNX1 translocation partner 1 has been reported to exhibit a favorable outcome. The quantitative polymerase chain reaction is a reliable method for assessing minimal residual disease persistence, and peripheral blood (PB) samples are as informative as bone marrow (BM) samples during follow-up monitoring. However, few studies have compared the spatial organization of leukemia-specific chromosomes between BM and PB. In the present study, paired BM and PB samples were extracted from 6 patients with acute myeloid leukaemia-M2 and compared using three-dimensional fluorescence in situ hybridization. Cells were classified into three types: Normal, proximal and malignant. Comparisons of proportions (% of all cells) of different cell types revealed no significant difference between BM and PB samples. The relative radial positions (RRPs; d/R) of chromosomes 8 and 21 were consistent for 2/3 of BM and PB samples. The RRPs of chromosomes in proximal pairs were more interior in nuclei compared with chromosomes in normal pairs for BM and PB samples. The consistency of the spatial organization of chromosomes between BM and PB suggests that PB may be an alternative to BM for research and clinical diagnosis.

Measurable Residual Disease at Induction Redefines Partial Response in Acute Myeloid Leukemia and Stratifies Outcomes in Patients at Standard Risk Without NPM1 Mutations

Purpose We investigated the effect on outcome of measurable or minimal residual disease (MRD) status after each induction course to evaluate the extent of its predictive value for acute myeloid leukemia (AML) risk groups, including NPM1 wild-type (wt) standard risk, when incorporated with other induction response criteria. Methods As part of the NCRI AML17 trial, 2,450 younger adult patients with AML or high-risk myelodysplastic syndrome had prospective multiparameter flow cytometric MRD (MFC-MRD) assessment. After course 1 (C1), responses were categorized as resistant disease (RD), partial remission (PR), and complete remission (CR) or complete remission with absolute neutrophil count < 1,000/µL or thrombocytopenia < 100,000/μL (CRi) by clinicians, with CR/CRi subdivided by MFC-MRD assay into MRD+ and MRD-. Patients without high-risk factors, including Flt3 internal tandem duplication wt/- NPM1-wt subgroup, received a second daunorubicin/cytosine arabinoside induction; course 2 (C2) was intensified for patients with high-risk factors. Results Survival outcomes from PR and MRD+ responses after C1 were similar, particularly for good- to standard-risk subgroups (5-year overall survival [OS], 27% RD v 46% PR v 51% MRD+ v 70% MRD-; P < .001). Adjusted analyses confirmed significant OS differences between C1 RD versus PR/MRD+ but not PR versus MRD+. CRi after C1 reduced OS in MRD+ (19% CRi v 45% CR; P = .001) patients, with a smaller effect after C2. The prognostic effect of C2 MFC-MRD status (relapse: hazard ratio [HR], 1.88 [95% CI, 1.50 to 2.36], P < .001; survival: HR, 1.77 [95% CI, 1.41 to 2.22], P < .001) remained significant when adjusting for C1 response. MRD positivity appeared less discriminatory in poor-risk patients by stratified analyses. For the NPM1-wt standard-risk subgroup, C2 MRD+ was significantly associated with poorer outcomes (OS, 33% v 63% MRD-, P = .003; relapse incidence, 89% when MRD+ ≥ 0.1%); transplant benefit was more apparent in patients with MRD+ (HR, 0.72; 95% CI, 0.31 to 1.69) than those with MRD- (HR, 1.68 [95% CI, 0.75 to 3.85]; P = .16 for interaction). Conclusion MFC-MRD can improve outcome stratification by extending the definition of partial response after first induction and may help predict NPM1-wt standard-risk patients with poor outcome who benefit from transplant in the first CR.

Association between OGG1 S326C CC genotype and elevated relapse risk in acute myeloid leukemia

Recent studies have shown that tumors of relapsed acute myeloid leukemia (AML) present additional genetic mutations compared to the primary tumors. The base excision repair (BER) pathway corrects oxidatively damaged mutagenic bases and plays an important role in maintaining genetic stability. The purpose of the present study was to investigate the relationship between BER functional polymorphisms and AML relapse. We focused on five major polymorphisms: OGG1 S326C, MUTYH Q324H, APE1 D148E, XRCC1 R194W, and XRCC1 R399Q. Ninety-four adults with AML who achieved first complete remission were recruited. Genotyping was performed with the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The OGG1 S326C CC genotype (associated with lower OGG1 activity) was observed more frequently in patients with AML relapse [28.9 vs. 8.9%, odds ratio (OR) = 4.10, 95% confidence interval (CI) = 1.35-12.70, P = 0.01]. Patients with the CC genotype exhibited shorter relapse-free survival (RFS). Moreover, the TCGA database suggested that low OGG1 expression in AML cells is associated with a higher frequency of mutations. The present findings suggest that the OGG1 S326C polymorphism increased the probability of AML relapse and may be useful as a prognostic factor for AML relapse risk.

Time to repeal and replace response criteria for acute myeloid leukemia?

The International Working Group (IWG) response criteria for acute myeloid leukemia, published in 2003, have remained the standard by which the efficacy of new drugs is measured in clinical trials. Over the last decade, concepts related to treatment response have been challenged by several factors; for example, the dissociation between early clinical response and survival outcome in older patients, the recognition that epigenetic and newer differentiating-agent therapies may produce delayed responses and also hematologic improvement/transfusion independence without a morphologic response, and evidence that remissions without minimal (or measurable) residual disease (MRD) may result in outcomes superior to those of morphologic remissions with persistent MRD. The evolving role of MRD status as a potential surrogate for predicting long-term survival has enhanced the clinical need to standardize and incorporate emerging technologies that enable deeper responses beyond those recognized by the IWG, and to pre-emptively identify patients at risk of early relapse. The potential for therapeutic interventions to erase MRD and alter the natural history represents an important and open research question. Reviewed here are some of the implications and challenges associated with establishing and incorporating new treatment response criteria, initially into clinical research, and eventually into real-world practice.

Phosphoprotein DIGE profiles reflect blast differentiation, cytogenetic risk stratification, FLT3/NPM1 mutations and therapy response in acute myeloid leukaemia

Acute myeloid leukaemia (AML) is an aggressive blood cancer characterized by a distinct block in differentiation of myeloid progenitors, recurrent chromosomal translocations and gene mutations of which >50% involve signal transduction through dysregulated kinases and phosphatases. In search for novel protein biomarkers for disease stratification we investigated the phosphoproteome in leukaemic cells from 62 AML patients at time of diagnosis using immobilized metal-affinity chromatography, protein separation by two-dimensional differential gel electrophoresis (2D-DIGE) and mass spectrometry before validation by selected reaction monitoring (SRM). Unsupervised clustering found 27 phosphoproteins significantly discriminating patients according to leukaemic cell differentiation (French-American-British (FAB) classification), cytogenetic and mutational (FLT3, NPM1) status or response to chemotherapy. Monocytic differentiation (FAB M4-M5) correlated with enrichment of proteins involved in apoptosis (MOES, ANXA5 and EFHD2). TALDO, a protein associated with thrombocytopenia if down-regulated, was elevated in patients with wild type NPM1 compared to patients with NPM1 mutation. This study demonstrates the potential of quantitative proteomics in AML classification and risk stratification.

BIOLOGICAL SIGNIFICANCE

Patients diagnosed with AML are currently categorized according to cellular morphology, cytogenetic alterations and mutations, although the majority of these cellular and genetic alterations have no or unsolved impact on therapy selection or prognosis. We therefore explored the phosphoproteome for abundance changes associated with traditional classifiers to unravel patterns that could stratify patients at the protein level. MOES, ANXA5 and EFHD2 were confirmed by SRM to be correlated to monocytic differentiation, whilst TALDO was elevated in NPM1 wild type patients.

Hematopoietic stem cell transplantation in pediatric patients with acute myeloid leukemia without favorable cytogenetics

Intensified chemotherapy, HSCT, and supportive care improve the survival of pediatric patients with AML. However, no consensus has been reached regarding the role of HSCT in patients without favorable cytogenetics. We evaluated OS and EFS according to prognostic factors that affect clinical outcomes, including cytogenetics risk group, conditioning regimen, donor type, disease status at the time of HSCT, and number of chemotherapy cycles prior to HSCT in 65 pediatric patients with AML without favorable cytogenetics who underwent HSCT. Fifteen of the 65 patients died: three of TRM and 12 of disease-related mortality. The 5-year OS and EFS were 78.0% and 72.0%, respectively, and the 5-year cumulative relapse and TRM rates were 26.9% and 5.1%, respectively. Survival rates were not influenced by cytogenetic group (intermediated vs. poor), donor type (related vs. unrelated), transplant type (myeloablative vs. reduced-intensity conditioning), or number of pretransplant chemotherapy cycles (≤3 vs. >3 cycles). The low TRM rate and encouraging outcomes suggest that HSCT may be a feasible treatment for pediatric patients with AML without favorable cytogenetics.

[Factors associated with early treatment response in adults with acute myeloid leukemia]

Objective: To explore the factors influencing early treatment responses in adult with de novo acute myeloid leukemia (AML) . Methods: Data of consecutive newly-diagnosed AML (non-acute promyelocytic leukemia) adults were analyzed retrospectively. To assess the impact of clinical characteristics at diagnosis and induction regimen on achieving morphologic leukemia-free state (MLFS) , blood counts and minimal residual leukemia (MRD, positive MRD defined as RQ-PCR WT1 mRNA ≥0.6% and/or any level of abnormal blast population detected by flow cytometry) at the time of achieving MLFS. Results: 739 patients were included in this study. 406 (54.9%) patients were male, with a median age of 42 years (range, 18-65 years) . In the 721 evaluable patients, MLFS was achieved in 477 (66.2%) patients after the first induction regimen and 592 (82.1%) within two cycles. A total of 634 patients (87.9%) achieved MLFS, including 534 (84.2%) achieving a complete remission (CR, defined as MLFS with ANC ≥ 1×10(9)/L and PLT ≥ 100×10(9)/L) , 100 (15.8%) achieving a CRi (defined as MLFS with incomplete ANC or PLT recovery) , respectively. 260 (45.9%) patients of 566 (89.3%) who detected MRD at the time of achieving MLFS had positive MRD. Multivariate analyses showed that female gender, favorable-risk of SWOG criteria, IA10 and HAA/HAD as induction regimen were factors associated with achieving early MLFS. In addition, low bone marrow blasts, HGB ≥ 80 g/L, PLT counts<30×10(9)/L and mutated NPM1 without FLT3-ITD were factors associated with achieving MLFS after the first induction regimen; Negative FLT3-ITD mutation was factor associated with achieving MLFS within two cycles. PLT counts ≥30×10(9)/L and IA10, IA8 or HAA/HAD as induction chemotherapy were factors associated with achieving CR. Female gender, favorable-risk of SWOG criteria, FLT3-ITD mutation negative, mutated NPM1 without FLT3-ITD were factors associated with negative MRD. Conclusions: Female gender, favorable molecular markers or cytogenetics, and standard-dose induction regimen were key factors associated with higher probability of early and deep responses in adults with AML.

Therapeutic targeting of leukemic stem cells in acute myeloid leukemia - the biological background for possible strategies

INTRODUCTION

Acute myeloid leukemia (AML) is an aggressive malignancy, caused by the accumulation of immature leukemic blasts in blood and bone marrow. There is a relatively high risk of chemoresistant relapse even for the younger patients who can receive the most intensive antileukemic treatment. Treatment directed against the remaining leukemic and preleukemic stem cells will most likely reduce the risk of later relapse. Areas covered: Relevant publications were identified through literature searches. The authors searched for original articles and recent reviews describing (i) the characteristics of leukemic/preleukemic stem cells; (ii) the importance of the bone marrow stem cell niches in leukemogenesis; and (iii) possible therapeutic strategies to target the preleukemic/leukemic stem cells. Expert opinion: Leukemia relapse/progression seems to be derived from residual chemoresistant leukemic or preleukemic stem cells, and a more effective treatment directed against these cells will likely be important to improve survival both for patients receiving intensive treatment and leukemia-stabilizing therapy. Several possible strategies are now considered, including the targeting of the epigenetic regulation of gene expression, proapoptotic intracellular signaling, cell metabolism, telomere activity and the AML-supporting effects by neighboring stromal cells. Due to disease heterogeneity, the most effective stem cell-directed therapy will probably differ between individual patients.

Personalized Prognostic Risk Score for Long-Term Survival for Children with Acute Leukemia after Allogeneic Transplantation

We studied leukemia-free (LFS) and overall survival (OS) in children with acute myeloid (AML, n = 790) and acute lymphoblastic leukemia (ALL, n = 1096) who underwent transplantation between 2000 and 2010 and who survived for at least 1 year in remission after related or unrelated donor transplantation. Analysis of patient-, disease-, and transplantation characteristics and acute and chronic graft-versus-host disease (GVHD) was performed to identify factors with adverse effects on LFS and OS. These data were used to develop risk scores for survival. We did not identify any prognostic factors beyond 4 years after transplantation for AML and beyond 3 years for ALL. Risk score for survival for AML includes age, disease status at transplantation, cytogenetic risk group, and chronic GVHD. For ALL, the risk score includes age at transplantation and chronic GVHD. The 10-year probabilities of OS for AML with good (score 0, 1, or 2), intermediate (score 3), and poor risk (score 4, 5, 6, or 7) were 94%, 87%, and 68%, respectively. The 10-year probabilities of OS for ALL were 89% and 80% for good (score 0 or 1) and poor risk (score 2), respectively. Identifying children at risk for late mortality with early intervention may mitigate some excess late mortality.

CDC25 Inhibition in Acute Myeloid Leukemia-A Study of Patient Heterogeneity and the Effects of Different Inhibitors

Cell division cycle 25 (CDC25) protein phosphatases regulate cell cycle progression through the activation of cyclin-dependent kinases (CDKs), but they are also involved in chromatin modulation and transcriptional regulation. CDC25 inhibition is regarded as a possible therapeutic strategy for the treatment of human malignancies, including acute myeloid leukemia (AML). We investigated the in vitro effects of CDC25 inhibitors on primary human AML cells derived from 79 unselected patients in suspension cultures. Both the previously well-characterized CDC25 inhibitor NSC95397, as well as five other inhibitors (BN82002 and the novel small molecular compounds ALX1, ALX2, ALX3, and ALX4), only exhibited antiproliferative effects for a subset of patients when tested alone. These antiproliferative effects showed associations with differences in genetic abnormalities and/or AML cell differentiation. However, the responders to CDC25 inhibition could be identified by analysis of global gene expression profiles. The differentially expressed genes were associated with the cytoskeleton, microtubules, and cell signaling. The constitutive release of 28 soluble mediators showed a wide variation among patients and this variation was maintained in the presence of CDC25 inhibition. Finally, NSC95397 had no or only minimal effects on AML cell viability. In conclusion, CDC25 inhibition has antiproliferative effects on primary human AML cells for a subset of patients, and these patients can be identified by gene expression profiling.

Bone marrow evaluation for diagnosis and monitoring of acute myeloid leukemia

The diagnosis of acute myeloid leukemia (AML) can be made based on peripheral blood or bone marrow blasts. In this review, we will discuss the role of bone marrow evaluation and peripheral blood monitoring in the diagnosis, management, and follow up of AML patients. For patients with circulating blasts, it is reasonable to perform the necessary studies needed for diagnosis and risk stratification, including multiparametric flow cytometry, cytogenetics, and molecular analysis, on a peripheral blood specimen. The day 14 marrow is used to document hypocellularity in response to induction chemotherapy, but it is unclear if that assessment is necessary as it often does not affect immediate management. Currently, response assessments performed at count recovery for evaluation of remission and measurable residual disease rely on bone marrow sampling. For monitoring of relapse, peripheral blood evaluation may be adequate, but the sensitivity of bone marrow testing is in some cases superior. While bone marrow evaluation can certainly be avoided in particular situations, this cumbersome and uncomfortable procedure currently remains the de facto standard for response assessment.

Impact of salvage regimens on response and overall survival in acute myeloid leukemia with induction failure

We evaluated the impact of salvage regimens and allogeneic hematopoietic cell transplantation (allo-HCT) in acute myeloid leukemia (AML) with induction failure. Between 1993 and 2009, 3324 patients with newly diagnosed AML were enrolled in 5 prospective treatment trials of the German-Austrian AML Study Group. After first induction therapy with idarubicin, cytarabine and etoposide (ICE), 845 patients had refractory disease. In addition, 180 patients, although responding to first induction, relapsed after second induction therapy. Of the 1025 patients with induction failure, 875 (median age 55 years) received intensive salvage therapy: 7+3-based (n=59), high-dose cytarabine combined with mitoxantrone (HAM; n=150), with all-trans retinoic acid (A; A-HAM) (n=247), with gemtuzumab ozogamicin and A (GO; GO-A-HAM) (n=140), other intensive regimens (n=165), experimental treatment (n=27) and direct allo-HCT (n=87). In patients receiving intensive salvage chemotherapy (n=761), response (complete remission/complete remission with incomplete hematological recovery (CR/CRi)) was associated with GO-A-HAM treatment (odds ratio (OR), 1.93; P=0.002), high-risk cytogenetics (OR, 0.62; P=0.006) and age (OR for a 10-year difference, 0.75; P<0.0001). Better survival probabilities were seen in an extended Cox regression model with time-dependent covariables in patients responding to salvage therapy (P<0.0001) and having the possibility to perform an allo-HCT (P<0.0001). FLT3 internal tandem duplication, mutated IDH1 and adverse cytogenetics were unfavorable factors for survival.

Unmanipulated Haploidentical Hematopoietic Stem Cell Transplantation in First Complete Remission Can Abrogate the Poor Outcomes of Children with Acute Myeloid Leukemia Resistant to the First Course of Induction Chemotherapy

Allogeneic hematopoietic stem cell transplantation (HSCT) is an important therapy option for children with acute myeloid leukemia (AML) resistant to the first course of induction chemotherapy (IC_1st). We aimed to identify the efficacy of unmanipulated haploidentical HSCT (haplo-HSCT) in children with AML in the first complete remission and whether children resistant (IC_1st-resistant; n = 38) or sensitive (IC_1st-sensitive; n = 59) to the IC_1st can achieve comparable outcomes. The cumulative incidence of grades III to IV acute graft-versus-host disease (GVHD) and severe chronic GVHD was .0% versus 20.1% (P = .038) and 21.7% versus 13.2% (P = .238), respectively, for the IC_1st-resistant and IC_1st-sensitive groups. The 3-year cumulative incidence of relapse and nonrelapse mortality was 22.2% versus 7.6% (P = .061) and 5.3% versus 10.8% (P = .364), respectively, for the IC_1st-resistant and IC_1st-sensitive groups. The 3-year probability of overall survival and disease-free survival was 76.3% versus 83.0% (P = .657) and 72.5% versus 81.6% (P = .396), respectively, for the IC_1st-resistant and IC_1st-sensitive groups. Multivariate analysis failed to show significant differences in survival rates between the groups. Thus, our results show that unmanipulated haplo-HSCT may overcome the poor prognostic significance of IC_1st-resistance in children with AML, and it is valid as a postremission treatment for children with IC_1st-resistant AML lacking an HLA-matched donor.