Prediction of post-remission survival in acute myeloid leukaemia: a post-hoc analysis of the AML96 trial

Comparison of allo-SCT, auto-SCT and chemotherapy for the treatment of patients with low- or intermediate-risk acute myeloid leukemia: a network meta-analysis

BACKGROUND

The therapeutic status of allogeneic stem cell transplantation (allo-SCT) as a post-remission treatment for patients with high-risk acute myeloid leukemia (AML) was well-accepted. However, the optimal treatment for patients with low/favorable- or intermediate-risk AML who achieve complete remission has remained controversial. Therefore, we conducted a network meta-analysis to discuss this disputed problem.

METHODS

We compared the effects of treatment strategies including allo-SCT, autologous stem cell transplantation (auto-SCT) and consolidation chemotherapy (CT) for patients with low/favorable- or intermediate-risk AML. The pooled HRs and 95% CIs for overall survival and disease-free survival were estimated with Stata12 and R software. Thirty clinical studies with 6682 patients were included in the meta-analysis.

RESULTS

The results indicated that the treatment outcome of allo-SCT was the best, followed by auto-SCT, and CT was likely the worst in the total AML patients. In patients with low/favorable-risk AML, the treatment outcome of auto-SCT was likely ranked first, followed by allo-SCT, and CT was the worst. In patients with intermediate-risk AML, the treatment outcome of haploidentical stem cell transplantation (haplo-SCT) was the best, followed by allo-SCT (excluding haplo-SCT), and auto-SCT and CT were the worst. However, the median age of the haplo-SCT group was much younger than that of the control group, which may be one of the reasons for the better prognosis of the haplo-SCT group.

CONCLUSIONS

Patients with low/favorable- and intermediate-risk (non-high-risk) AML should prioritize allo-SCT if they are eligible for transplantation, and auto-SCT is optional. However, in the subgroup analysis, auto-SCT was the optimal treatment choice for patients with low/favorable-risk AML, and allo-SCT was the priority selection for patients with intermediate-risk AML, especially young patients. These findings could provide references for clinical practice.

Targeting PRMT9-mediated arginine methylation suppresses cancer stem cell maintenance and elicits cGAS-mediated anticancer immunity

Current anticancer therapies cannot eliminate all cancer cells, which hijack normal arginine methylation as a means to promote their maintenance via unknown mechanisms. Here we show that targeting protein arginine N-methyltransferase 9 (PRMT9), whose activities are elevated in blasts and leukemia stem cells (LSCs) from patients with acute myeloid leukemia (AML), eliminates disease via cancer-intrinsic mechanisms and cancer-extrinsic type I interferon (IFN)-associated immunity. PRMT9 ablation in AML cells decreased the arginine methylation of regulators of RNA translation and the DNA damage response, suppressing cell survival. Notably, PRMT9 inhibition promoted DNA damage and activated cyclic GMP-AMP synthase, which underlies the type I IFN response. Genetically activating cyclic GMP-AMP synthase in AML cells blocked leukemogenesis. We also report synergy of a PRMT9 inhibitor with anti-programmed cell death protein 1 in eradicating AML. Overall, we conclude that PRMT9 functions in survival and immune evasion of both LSCs and non-LSCs; targeting PRMT9 may represent a potential anticancer strategy.

Acute myeloid leukemia: negative prognostic impact of early blast persistence can be in part overcome by a later remission prior to post-induction therapy

In acute myeloid leukemia, there is an ongoing debate on the prognostic value of the early bone marrow assessment in patients receiving intensive therapy. In this retrospective study, we analyzed the prognostic impact of the early response in 1,008 patients with newly diagnosed acute myeloid leukemia, who were treated at our institution with intensive chemotherapy followed by consolidation chemotherapy and/or allogeneic hematopoietic stem cell transplantation (HSCT). We found that early blast persistence has an independent negative prognostic impact on overall survival, eventfree survival and relapse-free survival. This negative prognostic impact may only be overcome in patients showing at least a partial remission at the early bone marrow assessment and who subsequently achieve blast clearance by additional induction chemotherapy prior to consolidation therapy with allogeneic HSCT. In accordance, we propose that the time slope of remission is an additional leukemia-related dynamic parameter that reflects chemosensitivity and thus may inform post-induction therapy decision-making. In addition to patient-related factors, European LeukemiaNet risk group, measurable residual disease monitoring and donor availability, this may particularly apply to European LeukemiaNet intermediate-risk patients, for whom a decision between consolidation chemotherapy and allogeneic HSCT remains challenging in many cases.

A Phenogenetic Axis that Modulates Clinical Manifestation and Predicts Treatment Outcome in Primary Myeloid Neoplasms

Although the concept of "myeloid neoplasm continuum" has long been proposed, few comparative genomics studies directly tested this hypothesis. Here we report a multi-modal data analysis of 730 consecutive newly diagnosed patients with primary myeloid neoplasm, along with 462 lymphoid neoplasm cases serving as the outgroup. Our study identified a "Pan-Myeloid Axis" along which patients, genes, and phenotypic features were all aligned in sequential order. Utilizing relational information of gene mutations along the Pan-Myeloid Axis improved prognostic accuracy for complete remission and overall survival in adult patients of de novo acute myeloid leukemia and for complete remission in adult patients of myelodysplastic syndromes with excess blasts. We submit that better understanding of the myeloid neoplasm continuum might shed light on how treatment should be tailored to individual diseases.

Significance

The current criteria for disease diagnosis treat myeloid neoplasms as a group of distinct, separate diseases. This work provides genomics evidence for a "myeloid neoplasm continuum" and suggests that boundaries between myeloid neoplastic diseases are much more blurred than previously thought.

MRD Tailored Therapy in AML: What We Have Learned So Far

Acute myeloid leukemia (AML) is a heterogeneous clonal disease associated with a dismal survival, partly due to the frequent occurrence of relapse. Many patient- and leukemia-specific characteristics, such as age, cytogenetics, mutations, and measurable residual disease (MRD) after intensive chemotherapy, have shown to be valuable prognostic factors. MRD has become a rich field of research where many advances have been made regarding technical, biological, and clinical aspects, which will be the topic of this review. Since many laboratories involved in AML diagnostics have experience in immunophenotyping, multiparameter flow cytometry (MFC) based MRD is currently the most commonly used method. Although molecular, quantitative PCR based techniques may be more sensitive, their disadvantage is that they can only be applied in a subset of patients harboring the genetic aberration. Next-generation sequencing can assess and quantify mutations in many genes but currently does not offer highly sensitive MRD measurements on a routine basis. In order to provide reliable MRD results, MRD assay optimization and standardization is essential. Different techniques for MRD assessment are being evaluated, and combinations of the methods have shown promising results for improving its prognostic value. In this regard, the load of leukemic stem cells (LSC) has also been shown to add to the prognostic value of MFC-MRD. At this moment, MRD after intensive chemotherapy is most often used as a prognostic factor to help stratify patients, but also to select the most appropriate consolidation therapy. For example, to guide post-remission treatment for intermediate-risk patients where MRD positive patients receive allogeneic stem cell transplantation and MRD negative receive autologous stem cell transplantation. Other upcoming uses of MRD that are being investigated include: selecting the type of allogeneic stem cell transplantation therapy (donor, conditioning), monitoring after stem cell transplantation (to allow intervention), and determining drug efficacy for the use of a surrogate endpoint in clinical trials.

Hematopoietic Cell Transplantation in the Treatment of Newly Diagnosed Adult Acute Myeloid Leukemia: An Evidence-Based Review from the American Society of Transplantation and Cellular Therapy

The role of hematopoietic cell transplantation (HCT) in the management of newly diagnosed adult acute myeloid leukemia (AML) is reviewed and critically evaluated in this evidence-based review. An AML expert panel, consisting of both transplant and nontransplant experts, was invited to develop clinically relevant frequently asked questions covering disease- and HCT-related topics. A systematic literature review was conducted to generate core recommendations that were graded based on the quality and strength of underlying evidence based on the standardized criteria established by the American Society of Transplantation and Cellular Therapy Steering Committee for evidence-based reviews. Allogeneic HCT offers a survival benefit in patients with intermediate- and high-risk AML and is currently a part of standard clinical care. We recommend the preferential use of myeloablative conditioning in eligible patients. A haploidentical related donor marrow graft is preferred over a cord blood unit in the absence of a fully HLA-matched donor. The evolving role of allogeneic HCT in the context of measurable residual disease monitoring and recent therapeutic advances in AML with regards to maintenance therapy after HCT are also discussed.

Development and validation of a prognostic model for adult patients with acute myeloid leukaemia

Background

The high heterogeneity of acute myeloid leukaemia (AML) reflected in the patient- and disease-related factors accounts for the unsatisfactory prognosis despite the introduction of novel therapeutic approaches and drugs in recent years.

Methods

In the development set (n = 412), parameters including age, hematopoietic cell transplantation-comorbidity index, white blood cell count, hemoglobin, biallelic CEBPA mutations, DNMT3A mutations, FLT3-ITD/NPM1 status, and ELN cytogenetic risk status were identified as independent prognostic factors for overall survival (OS) in the multivariable Cox regression analysis. A nomogram combining these predictors for individual risk estimation was established thereby.

Findings

The prognostic model demonstrated promising performance in the development cohort. The calibration plot, C-index (0.74), along with the 1-, 2- and 3-year area under the receiver operating characteristic curve (AUC, 0.76, 0.79, and 0.74, respectively) in the validation set (n = 238) substantiated the robustness of the model. In addition to stratifying young (age ≤ 60 years) and elderly patients (age > 60 years) into three and two risk groups with significant distinct outcomes, the prognostic model succeeded in distinguishing eligible candidates for hematopoietic stem cell transplantation.

Interpretation

The prognostic model is capable of survival prediction, risk stratification and helping with therapeutic decision-making with the use of easily acquired variables in daily clinical routine.

Funding

This work was supported in part by grants from the National Natural Science Foundation of China (81770141), the National Key R&D Program of China (2016YFE0202800), and Shanghai Municipal Education Commission-Gaofeng Clinical Medicine Grant Support (20161406).

Risk stratification using FLT3 and NPM1 in acute myeloid leukemia patients autografted in first complete remission

FLT3-ITD and NPM1 mutation refine prognostic stratification in acute myeloid leukemia (AML) with intermediate-risk cytogenetics. However, data on their role in patients undergoing autologous stem cell transplantation (Auto-SCT) as post-remission therapy (PRT) are limited. We therefore sought to retrospectively evaluate the role of FLT3-ITD and NPM1 in a cohort of AML patients (n = 405) with intermediate-risk cytogenetics, autografted in first complete remission (CR1). Patients were transplanted between 2000 and 2014 and reported to the European Society for Blood and Marrow Transplantation (EBMT) registry. Leukemia-free survival (LFS) was the primary outcome. Median follow-up was 5.5 years. FLT3-ITD^neg/NPM1^WT was the leading molecular subtype (50%), followed by FLT3-ITD^neg/NPM1^mut (30%). In the univariate analysis, molecular subtype was associated with LFS, overall survival (OS), and relapse incidence (RI) (p < 0.001); 5-year LFS: FLT3-ITD^neg/NPM1^mut 62%, FLT3-ITD^pos/NPM1^mut 38%, FLT3-ITD^neg/NPM1^WT 32%, and FLT3-ITD^pos/NPM1^WT 21%. At 5 years, OS and RI in the FLT3-ITD^neg/NPM1^mut subtype were 74% and 35%, respectively. The corresponding OS and RI in other subtypes were below 48% and over 57%. In a Cox multivariable model, molecular subtype was the strongest predictor of LFS, OS, and relapse. In conclusion, AML patients with intermediate-risk cytogenetics and FLT3-ITD^neg/NPM1^mut experience favorable outcomes when autografted in CR1, suggesting that Auto-SCT is a valid PRT option.

Sensitive detection of EBV microRNAs across cancer spectrum reveals association with decreased survival in adult acute myelocytic leukemia

Epstein Barr virus (EBV) is the etiologic agent involved in numerous human cancers. After infecting the host, EBV establishes a latent infection, with low levels of messenger RNA (mRNA) and protein expression, evolved to evade immune recognition. Conversely, EBV microRNAs (miRNA) are expressed ubiquitously and abundantly within infected cells. Their role in tumor biology and clinical outcomes across the spectrum of cancer is not fully explained. Here, we applied our bioinformatics pipeline for quantitative EBV miRNA detection to examine sequencing data of 8,955 individual tumor samples across 27 tumor types representing the breadth of cancer. We uncover an association of intermediate levels of viral miRNA with decreased survival in adult acute myeloid leukemia (AML) patients (P = 0.00013). Prognostic modeling of this association suggests that increased EBV miRNA levels represent an independent risk factor for poor patient outcomes. Furthermore, we explore differences in expression between elevated and absent viral miRNA loads in adult AML tumors finding that EBV positivity was associated with proinflammatory signals. Together, given no associations were found for pediatric AML, our analyses suggests EBV positivity has the potential for being a prognostic biomarker and might represent a surrogate measure related to immune impairment in adult patients.

Importance of prognostic stratification via gene mutation analysis in elderly patients with acute myelogenous leukemia

INTRODUCTION

Acute myelogenous leukemia (AML) in elderly patients is associated with an increased incidence of complications and treatment-related toxicity because of the frequency of comorbid disease and age-related deterioration in organ function. Despite advances in AML treatment in recent years, elderly patients have experienced limited benefit, and their outcomes remain poor. This study aimed to perform a comprehensive gene mutation analysis in elderly AML patients and identify gene mutations that could serve as prognostic factors.

METHODS

An analysis of gene mutations was performed for 281 AML patients, including 98 elderly patients aged 65 years or above.

RESULTS

Compared to younger AML patients, elderly patients showed a higher frequency of the following gene mutations: TP53 (P = 0.026), PTPN11 (P = 0.006), RUNX1 (P = 0.024), TET2 (P = 0.002), and ASXL1 (P = 0.023). The complete remission rate was significantly lower in DNMT3A mutation-positive cases (4.26%, P = 0.011) and TP53 mutation-positive cases (2.13%, P = 0.031) than in negative cases. The overall survival rate was significantly poorer in cases with FLT3-ITD (P = 0.003), DNMT3A (P = 0.033), or TP53 mutation (P < 0.001). Conversely, cases with PTPN11 mutation (P = 0.014) had a significantly more favorable prognosis. In multivariate analysis, FLT3-ITD (P = 0.011) and TP53 mutation positivity (P = 0.002) were independent poor prognostic factors, as were a performance status of 3 or above (P < 0.001) and poor cytogenetic prognosis (P = 0.001). In contrast, PTPN11 mutation positivity (P = 0.023) was an independent favorable prognosis factor.

CONCLUSION

Analysis of gene mutations in elderly AML patients is very important, not only for establishing prognosis, but also for introducing appropriate molecular-targeted treatments.

Autologous Stem Cell Transplantation Is a Viable Postremission Therapy for Intermediate-Risk Acute Myeloid Leukemia in First Complete Remission in the Absence of a Matched Identical Sibling: A Meta-Analysis

BACKGROUND

The preferred type of postremission therapy (PRT) for intermediate-risk acute myeloid leukemia (AML) in first complete remission (CR1) is a subject of continued debate. Although allogeneic stem cell transplantation (alloSCT) is regarded as a curative strategy for AML, the efficacy of autologous stem cell transplantation (autoSCT) for patients without a matched sibling donor (MSD) has remained controversial.

METHODS

To compare survival outcomes after alloSCT versus autoSCT for patients with intermediate-risk AML in CR1, we performed a meta-analysis of 11 clinical studies. The outcomes included relapse-free survival (RFS), overall survival (OS), relapse rate (RR), and treatment-related mortality (TRM).

RESULTS

Compared with autoSCT, alloSCT showed better RFS, OS, and RR benefits, but higher TRM. Subgroup analysis based on donor category (MSD and matched unrelated donor [MUD]) of alloSCT showed alloSCT from MSD rather than from MUD had better OS benefits compared to autoSCT. For fms-like tyrosine kinase 3 internal tandem duplications (FLT3-ITD) wild-type patients, alloSCT and autoSCT had comparable RFS and OS outcomes.

CONCLUSION

Our results suggest that, in the absence of an available MSD, autoSCT remains a viable PRT alternative for intermediate-risk AML in CR1, especially for FLT3-ITD wild-type patients.

Iron overload is correlated with impaired autologous stem cell mobilization and survival in acute myeloid leukemia

BACKGROUND

Patients with acute myeloid leukemia (AML) undergoing consolidation with autologous stem cell transplantation (ASCT) depend on the successful mobilization of peripheral blood stem cells. However, the factors affecting the mobilization potential in AML patients and, in particular, the effect of transfusion-related iron overload on peripheral blood stem cell mobilization are largely unknown.

STUDY DESIGN AND METHODS

We investigated the association of varying levels of iron overload and stem cell mobilization efficacy in consecutive AML patients after two induction cycles.

RESULTS

A total of 113 AML patients in early first complete remission underwent the mobilization procedure. While 84 (74.3%) patients had serum ferritin levels exceeding 1000 μg/L, 26 (23.0%) patients had levels even higher than 2000 μg/L. Iron overload correlated with the number of preceding red blood cell transfusions and inversely correlated with circulating CD34+ cell levels (p = 0.04) at apheresis. Finally, the median progression-free and overall survival rates of patients with ferritin levels of higher than 2000 μg/L were shorter with 332 days versus 2156 days (p = 0.04) and 852 days versus 2235 days (p = 0.04), respectively.

CONCLUSION

Our data suggest that transfusion-related iron overload is suppressing the mobilization potential and is associated with inferior outcome in AML.

Profiling of aberrant DNA methylation in acute myeloid leukemia reveals subclasses of CG-rich regions with epigenetic or genetic association

Malignant transformation is frequently associated with disease-specific epigenetic alterations, but the underlying mechanisms and pathophysiological consequences remain poorly understood. Here, we used global comparative DNA methylation profiling at CG-rich regions of 27 acute myeloid leukemia (AML) samples to select a subset of aberrantly methylated CG-rich regions (~400 regions, ~15,000 CpGs) for quantitative DNA methylation profiling in a large cohort of AML patients (n = 196) using MALDI-TOF analysis of bisulfite-treated DNA. Meta-analysis separated a subgroup of CG-rich regions showing highly correlated DNA methylation changes that were marked by histone H3 lysine 27 trimethylation in normal hematopoietic progenitor cells. While the group of non-polycomb group (PcG) target regions displayed methylation patterns that correlated well with molecular and cytogenetic markers, PcG target regions displayed a much weaker association with genetic features. However, the degree of methylation gain across the latter panel showed significant correlation with active DNMT3A levels and with overall survival. Our study suggests that both epigenetic as well as genetic aberrations underlay AML-related changes in DNA methylation at CG-rich regions and that the former may provide a marker to improve classification and prognostication of adult AML patients.

Sorafenib promotes graft-versus-leukemia activity in mice and humans through IL-15 production in FLT3-ITD-mutant leukemia cells

Individuals with acute myeloid leukemia (AML) harboring an internal tandem duplication (ITD) in the gene encoding Fms-related tyrosine kinase 3 (FLT3) who relapse after allogeneic hematopoietic cell transplantation (allo-HCT) have a 1-year survival rate below 20%. We observed that sorafenib, a multitargeted tyrosine kinase inhibitor, increased IL-15 production by FLT3-ITD+ leukemia cells. This synergized with the allogeneic CD8+ T cell response, leading to long-term survival in six mouse models of FLT3-ITD+ AML. Sorafenib-related IL-15 production caused an increase in CD8+CD107a+IFN-γ+ T cells with features of longevity (high levels of Bcl-2 and reduced PD-1 levels), which eradicated leukemia in secondary recipients. Mechanistically, sorafenib reduced expression of the transcription factor ATF4, thereby blocking negative regulation of interferon regulatory factor 7 (IRF7) activation, which enhanced IL-15 transcription. Both IRF7 knockdown and ATF4 overexpression in leukemia cells antagonized sorafenib-induced IL-15 production in vitro. Human FLT3-ITD+ AML cells obtained from sorafenib responders following sorafenib therapy showed increased levels of IL-15, phosphorylated IRF7, and a transcriptionally active IRF7 chromatin state. The mitochondrial spare respiratory capacity and glycolytic capacity of CD8+ T cells increased upon sorafenib treatment in sorafenib responders but not in nonresponders. Our findings indicate that the synergism of T cells and sorafenib is mediated via reduced ATF4 expression, causing activation of the IRF7-IL-15 axis in leukemia cells and thereby leading to metabolic reprogramming of leukemia-reactive T cells in humans. Therefore, sorafenib treatment has the potential to contribute to an immune-mediated cure of FLT3-ITD-mutant AML relapse, an otherwise fatal complication after allo-HCT.

Autologous hematopoietic cell transplantation for adult acute myeloid leukemia: An obsolete or resurfacing concept?

Improving long-term outcomes of adult acute myeloid leukemia (AML) patients remains a challenge. Major scientific and clinical advances have led to a better understanding of the disease biology, and the majority of patients achieve a complete remission (CR) after induction therapy. Relapse risk, however, remains considerable and is the leading cause of death in this patient population. Significant efforts to improve outcomes emphasize use of post-remission therapies such as hematopoietic cell transplantation (HCT), an increasingly utilized modality. Improvement in transplantation techniques, understanding of donor:recipient histocompatibility, and increased availability of alternative donors have resulted in greater use of allogeneic HCT. Despite a graft-versus-leukemia effect and lower post-HCT relapse rates, allogeneic HCT continues to be plagued by treatment-related mortality (TRM) and chronic graft-versus-host disease. Better understanding of AML risk stratification and issues relating to minimal residual disease (MRD) as well as extremely low TRM rates with autografts have prompted clinicians to re-explore use of autologous HCT in subsets of favorable and intermediate-risk CR1 AML patients. Herein, we highlight the evolving literature and treatment outcomes for autologous HCT in AML. We provide recommendations for considering this therapeutic modality for treatment intensification in AML.

Long-Term Outcome of Autologous Hematopoietic Stem Cell Transplantation (AHSCT) for Acute Myeloid Leukemia (AML)- Single Center Retrospective Analysis

For patients with acute myeloid leukemia (AML) in complete remission without an acceptable HLA donor, the autologous hematopoietic stem cell transplantation (AHSCT) may remain a therapeutic option as remission consolidation, however its role is still a subject of continued debate. One hundred and twenty patients who underwent AHSCT for AML were included in this retrospective single center analysis. The procedure was performed over a 19 years period and transplanted patients were in first complete remission (CR1; n = 109) or in second CR (CR2; n = 11). The median age at transplant was 37 years (range 18–64). The source of stem cells was bone marrow (n = 61; 50.8%), peripheral blood (n = 36; 30%) and bone marrow with peripheral blood (n = 23; 19.2%). The median time from AML diagnosis to AHSCT was 0.8 year (range 0.3–4.4) and the median follow-up after AHSCT for surviving patients was 12.8 years (range 3.1–20.5). The median LFS was 1.1 year. The probability of LFS calculated at 5 years and 10 years after transplantation was 28% (95%CI, 22%–32%) and 21% (95%CI, 18%–24%), respectively. The last relapse occurred 14.8 years after AHSCT and among patients who survived >2 years, 28.4% (27/95) had leukemia recurrence. The median OS was 1.7 years. The probability of OS after 5 years and 10 years was 29% and 22%, respectively. There was a tendency for increased LFS for patients younger than 50 years at transplant if compared to older population. AHSCT for AML was safe with acceptable toxicity profile. Leukemia recurrence remained the leading cause of death.

Comparison of Autologous and Unrelated Transplants for Cytogenetically Normal Acute Myelogenous Leukemia

Allogeneic stem cell transplantation (SCT) from an HLA-matched sibling donor (MSD) is a postremission treatment that offers a potential cure for adults with cytogenetically normal (CN) acute myelogenous leukemia (AML) in first complete remission (CR1). The best alternative in the absence of an MSD remains unclear, however. The aim of this study was to retrospectively compare the outcomes of autologous peripheral blood stem cell transplantation (auto-PBSCT; n = 177) and allogeneic bone marrow transplantation (BMT) from an HLA-matched unrelated donor (MUD; n = 173) in adult patients with CN-AML/CR1. Both the multivariate analysis (hazard ratio [HR], 1.18; 95% confidence interval [CI], 0.71 to 1.97; P = .53) and propensity score models (HR, 1.40; 95% CI, 0.80 to 2.43; P = .24) indicated that the leukemia-free survival (LFS) rate of auto-PBSCT was not significantly different from that of MUD-BMT. These results suggest that in the absence of an available MSD, auto-PBSCT remains a viable alternative as postremission therapy in patients with CN-AML/CR1.

Diagnosis and management of AML in adults: 2017 ELN recommendations from an international expert panel

The first edition of the European LeukemiaNet (ELN) recommendations for diagnosis and management of acute myeloid leukemia (AML) in adults, published in 2010, has found broad acceptance by physicians and investigators caring for patients with AML. Recent advances, for example, in the discovery of the genomic landscape of the disease, in the development of assays for genetic testing and for detecting minimal residual disease (MRD), as well as in the development of novel antileukemic agents, prompted an international panel to provide updated evidence- and expert opinion-based recommendations. The recommendations include a revised version of the ELN genetic categories, a proposal for a response category based on MRD status, and criteria for progressive disease.

Should autotransplantation in acute myeloid leukemia in first complete remission be revisited?

PURPOSE OF REVIEW

Despite numerous studies, the best postremission therapy in acute myeloid leukemia (AML) is a subject of intense controversy. Major prognostic factors for disease outcome are the genetic alterations of AML, patient's age, and performance status. AML is more common in older adults, with a median age of 72 years. However, in this age group the unfavorable cytogenetics dominates at a time when biologically it may be most difficult to administer optimal intensive therapy.

RECENT FINDINGS

Autologous stem cell transplantation (ASCT) enables the administration of high-dose therapy supported by stem cell infusion with a treatment-related toxicity not significantly higher than that associated with chemotherapy and significantly lower than in allogeneic stem cell transplantation. The dilemma of best postremission therapy has not been resolved because of the paucity of randomized controlled studies, especially in various cytogenetic risk and age groups. Instead, the use of genetic randomization by donor availability, analysis of outcome based on intention-to-treat, and mixed populations in the registry data produce variable results.

SUMMARY

ASCT has been associated with prolonged disease-free survival as compared to chemotherapy, especially in the favorable and intermediate risk groups. Advances in immunotherapy in AML may propel ASCT as a platform for various immunologic maneuvers.

Multigene Measurable Residual Disease Assessment Improves Acute Myeloid Leukemia Relapse Risk Stratification in Autologous Hematopoietic Cell Transplantation

We report here the largest study to date of adult patients with acute myeloid leukemia (AML) tested for measurable residual disease (MRD) at the time of autologous hematopoietic cell transplantation (auto-HCT). Seventy-two adult patients who underwent transplantation between 2004 and 2013 at a single academic medical center (University of California San Francisco) were eligible for this retrospective study based on availability of cryopreserved granulocyte colony-stimulating factor (GCSF)-mobilized autologous peripheral blood progenitor cell (PBPC) leukapheresis specimens ("autografts"). Autograft MRD was assessed by molecular methods (real-time quantitative PCR [RQ-PCR] for Wilms tumor 1 (WT1) alone or a multigene panel) and by multiparameter flow cytometry (MPFC). WT1 RQ-PCR testing of the autograft had low sensitivity for relapse prediction (14%) and a negative predictive value of 51%. MPFC failed to identify MRD in any of 34 autografts tested. Combinations of molecular MRD assays, however, improved prediction of post-auto-HCT relapse. In multivariate analysis of clinical variables, including age, gender, race, cytogenetic risk category, and CD34⁺ cell dose, only autograft multigene MRD as assessed by RQ-PCR was statistically significantly associated with relapse. One year after transplantation, only 28% patients with detectable autograft MRD were relapse free, compared with 67% in the MRD-negative cohort. Multigene MRD, while an improvement on other methods tested, was however suboptimal for relapse prediction in unselected patients, with specificity of 83% and sensitivity of 46%. In patients with known chromosomal abnormalities or mutations, however, better predictive value was observed with no relapses observed in MRD-negative patients in the first year after auto-HCT compared with 83% incidence of relapse in the MRD-positive patients (hazard ratio, 12.45; P = .0016). In summary, increased personalization of MRD monitoring by use of a multigene panel improved the ability to risk stratify patients for post-auto-HCT relapse. WT1 RQ-PCR and flow cytometric assessment for AML MRD in autograft samples had limited value for predicting relapse after auto-HCT. We demonstrate that cryopreserved autograft material presents unique challenges for AML MRD testing because of the masking effects of previous GCSF exposure on gene expression and flow cytometry signatures. In the absence of information regarding diagnostic characteristics, sources other than GCSF-stimulated PBSC leukapheresis specimens should be considered as alternatives for MRD testing in AML patients undergoing auto-HCT.

Comparative value of post-remission treatment in cytogenetically normal AML subclassified by NPM1 and FLT3-ITD allelic ratio

Post-remission treatment (PRT) in patients with cytogenetically normal (CN) acute myeloid leukemia (AML) in first complete remission (CR1) is debated. We studied 521 patients with CN-AML in CR1, for whom mutational status of NPM1 and FLT3-ITD was available, including the FLT3-ITD allelic ratio. PRT consisted of reduced intensity conditioning (RIC) allogeneic hematopoietic stem cell transplantation (alloHSCT) (n=68), myeloablative conditioning (MAC) alloHSCT (n=137), autologous hematopoietic stem cell transplantation (autoHSCT) (n=168) or chemotherapy (n=148). Favorable overall survival (OS) was found for patients with mutated NPM1 without FLT3-ITD (71±4%). Outcome in patients with a high FLT3-ITD allelic ratio appeared to be very poor with OS and relapse-free survival (RFS) of 23±8% and 12±6%, respectively. Patients with wild-type NPM1 without FLT3-ITD or with a low allelic burden of FLT3-ITD were considered as intermediate-risk group because of similar OS and RFS at 5 years, in which PRT by RIC alloHSCT resulted in better OS and RFS as compared with chemotherapy (hazard ratio (HR) 0.56, P=0.022 and HR 0.50, P=0.004, respectively) or autoHSCT (HR 0.60, P=0.046 and HR 0.60, P=0.043, respectively). The lowest cumulative incidence of relapse (23±4%) was observed following MAC alloHSCT. These results suggest that alloHSCT may be preferred in patients with molecularly intermediate-risk CN-AML, while the choice of conditioning type may be personalized according to risk for non-relapse mortality.

Comparable outcomes between autologous and allogeneic transplant for adult acute myeloid leukemia in first CR

Although allogeneic hematopoietic stem cell transplantation from an HLA-matched sibling donor (MSD) is a potentially curative post-remission treatment for adults with acute myeloid leukemia (AML) in their first CR, transplant-related morbidity and mortality remains a major drawback. We retrospectively compared the outcomes of patients who underwent autologous peripheral blood stem cell transplantation (auto-PBSCT; n=375) with those who underwent allogeneic bone marrow transplantation (allo-BMT; n=521) and allo-PBSCT (n=380) from MSDs for adults with AML/CR1, in which propensity score models were used to adjust selection biases among patients, primary physicians and institutions to overcome ambiguity in the patients' background information. Both the multivariate analysis and propensity score models indicated that the leukemia-free survival rate of auto-PBSCT was not significantly different from that of allo-BMT (hazard ratio (HR), 1.23; 95% confidence interval (CI), 0.92 to 1.66; P=0.16) and allo-PBSCT (HR, 1.13; 95% CI, 0.85-1.51; P=0.40). The current results suggest that auto-PBSCT remains a promising alternative treatment for patients with AML/CR1 in the absence of an available MSD.

Hematopoietic stem cell transplantation for patients with AML in first complete remission

Postremission therapy in patients with acute myeloid leukemia (AML) may consist of continuing chemotherapy or transplantation using either autologous or allogeneic stem cells. Patients with favorable subtypes of AML generally receive chemotherapeutic consolidation, although recent studies have also suggested favorable outcome after hematopoietic stem cell transplantation (HSCT). Although allogeneic HSCT (alloHSCT) is considered the preferred type of postremission therapy in poor- and very-poor-risk AML, the place of alloHSCT in intermediate-risk AML is being debated, and autologous HSCT is considered a valuable alternative that may be preferred in patients without minimal residual disease after induction chemotherapy. Here, we review postremission transplantation strategies using either autologous or allogeneic stem cells. Recent developments in the field of alternative donors, including cord blood and haploidentical donors, are highlighted, and we discuss reduced-intensity alloHSCT in older AML recipients who represent the predominant category of patients with AML who have a high risk of relapse in first remission.

Efficacy of Allogeneic Hematopoietic Stem Cell Transplantation in Intermediate-Risk Acute Myeloid Leukemia Adult Patients in First Complete Remission: A Meta-Analysis of Prospective Studies

Hematopoietic stem cell transplantation (HSCT) and consolidation chemotherapy have been used to treat intermediate-risk acute myeloid leukemia (AML) patients in first complete remission (CR1). However, it is still unclear which treatments are most effective for these patients. The aim of our study was to analyze the relapse-free survival (RFS) and overall survival (OS) benefit of allogeneic HSCT (alloHSCT) for intermediate-risk AML patients in CR1. A meta-analysis of prospective trials comparing alloHSCT to non-alloHSCT (autologous HSCT [autoHSCT] and/or chemotherapy) was undertaken. We systematically searched PubMed, Embase, and the Cochrane Library though October 2014, using keywords and relative MeSH or Emtree terms, 'allogeneic'; 'acut*' and 'leukem*/aml/leukaem*/leucem*/leucaem*'; and 'nonlympho*' or 'myelo*'. A total of 7053 articles were accessed. The primary outcomes were RFS and OS, while the secondary outcomes were treatment-related mortality (TRM) and relapse rate (RR). Hazard ratios (HR) and 95% confidence intervals (CI) were calculated for each outcome. The primary outcomes were RFS and OS, while the secondary outcomes were TRM and RR. We included 9 prospective controlled studies including 1950 adult patients. Patients with intermediate-risk AML in CR1 who received either alloHSCT or non-alloHSCT were considered eligible. AlloHSCT was found to be associated with significantly better RFS, OS, and RR than non-alloHSCT (HR, 0.684 [95% CI: 0.48, 0.95]; HR, 0.76 [95% CI: 0.61, 0.95]; and HR, 0.58 [95% CI: 0.45, 0.75], respectively). TRM was significantly higher following alloHSCT than non-alloHSCT (HR, 3.09 [95% CI: 1.38, 6.92]). However, subgroup analysis showed no OS benefit for alloHSCT over autoHSCT (HR, 0.99 [95% CI: 0.70, 1.39]). In conclusion, alloHSCT is associated with more favorable RFS, OS, and RR benefits (but not TRM outcomes) than non-alloHSCT generally, but does not have an OS advantage over autoHSCT specifically, in patients with intermediate-risk AML in CR1.

Is allogeneic transplantation really the best treatment for FLT3/ITD-positive acute myeloid leukemia? A systematic review

Fetal liver tyrosine kinase 3 (FLT3)-internal tandem duplications (ITDs) has been used as a powerful adverse prognostic indicator for acute myeloid leukemia (AML) in any age group. Evidence is mixed regarding the effects of allogeneic transplantation (allo-HSCT) in first complete remission (CR) for patients with FLT3/ITD AML. To fill this gap, this study provides a systematic review and meta-analysis of patients with FLT3/ITD AML receiving HSCT. A search of PubMed, Embase, and OVID yielded 1706 abstracts, two researchers screening the trials based on inclusion and exclusion criteria, and assessed the methodology quality independently. Meta-analysis showed that compared with chemotherapy, both allo-HSCT and autologous hematopoietic cell transplantation (auto-HSCT) can reduce the relapse rate (p < 0.01) and improve both the OS (p < 0.01) and DFS (p < 0.01). But when compared allo-HSCT with auto-HSCT, the OS (p = 0.27) and DFS (p = 0.19) have no statistical significance, and only the relapse indicator has statistical significance, p < 0.01. Based on the results, we can conclude that allo-HSCT is an efficient therapy approach for patients with FLT3/ITD AML. Chemotherapy cannot change the poor prognosis. Auto-HSCT can improve OS and DFS, but it cannot reduce the relapse rate.

Acute myeloid leukemia ontogeny is defined by distinct somatic mutations

Acute myeloid leukemia (AML) can develop after an antecedent myeloid malignancy (secondary AML [s-AML]), after leukemogenic therapy (therapy-related AML [t-AML]), or without an identifiable prodrome or known exposure (de novo AML). The genetic basis of these distinct pathways of AML development has not been determined. We performed targeted mutational analysis of 194 patients with rigorously defined s-AML or t-AML and 105 unselected AML patients. The presence of a mutation in SRSF2, SF3B1, U2AF1, ZRSR2, ASXL1, EZH2, BCOR, or STAG2 was >95% specific for the diagnosis of s-AML. Analysis of serial samples from individual patients revealed that these mutations occur early in leukemogenesis and often persist in clonal remissions. In t-AML and elderly de novo AML populations, these alterations define a distinct genetic subtype that shares clinicopathologic properties with clinically confirmed s-AML and highlights a subset of patients with worse clinical outcomes, including a lower complete remission rate, more frequent reinduction, and decreased event-free survival. This trial was registered at www.clinicaltrials.gov as #NCT00715637.

Higher percentage of CD34 + CD38- cells detected by multiparameter flow cytometry from leukapheresis products predicts unsustained complete remission in acute myeloid leukemia

Relapse in acute myeloid leukemia (AML) after chemotherapy reflects the persistence of resistant leukemia stem cells (LSCs). These cells have been described in the CD34 + CD38- cell fraction. Leukapheresis products were harvested in 123 patients in morphological complete remission and analyzed by multiparameter flow cytometry. The CD34 + CD38- cell population showed a prognostic impact on survival. Median event-free survival (EFS) was 8.2 months (3-year EFS: 29%) for those with a higher percentage of CD34 + CD38- versus 91.9 months (3-year EFS: 62%) for those with a lower percentage for the entire cohort. These differences were confirmed in patients undergoing autologous stem cell transplant, with median EFS of 7.3 months versus 91.1 months (3-year EFS: 31% vs. 70%). Higher proportions of CD34 + CD38- cells were associated with adverse cytogenetics and with earlier relapses. Higher percentages of CD34 + CD38- cells in apheresis products reflect inadequate in vivo purging and reliably distinguish samples enriched in LSCs from those involving mainly normal cells.

Wilms' tumor gene 1 transcript levels in leukapheresis of peripheral blood hematopoietic cells predict relapse risk in patients autografted for acute myeloid leukemia

Autologous hematopoietic stem cell transplantation (ASCT) is a curative option alternative to allogeneic transplantation for patients with acute myeloid leukemia (AML). Relapse after ASCT can be due to contamination with leukemic blasts of autologous peripheral blood stem cells (PBSCs) collected by leukapheresis (LK). Identification and quantification of a minimal residual disease (MRD) marker in PBSCs could be relevant in determining the relapse risk after ASCT. High levels of the WT1 gene transcript in bone marrow of AML patients after treatment completion predict disease relapse. We evaluated WT1 transcript levels in autologous PBSC from LK used for ASCT in 30 consecutive AML patients in complete remission (CR) and established a correlation with clinical outcome. At diagnosis, all patients had WT1 overexpression. All patients were in morphological and genetic CR at the time of PBSC collection and before ASCT. Real-time quantitative PCR of WT1 was performed in samples of each LK, using TaqMan technology on RNA from mononucleated cells. The median WT1 transcript level in the PBSC graft (WT1-LK) of patients who relapsed was significantly higher than of those who did not relapse after transplantation (P <.0001). We defined a cut-off level of 80 WT1-LK copies/ABL 10e4 copies to discriminate between positive and negative PBSC grafts. The cut-off level was strongly associated with disease recurrence, DFS and OS. Our study represents the largest series of patients evaluating WT1 as a marker of MRD in PBSC LK products using a completely standardized real-time WT1-reverse transcriptase-PCR based assay. These data, if confirmed by prospective study, will help to determine an individual patient's adapted postremission allocation strategy.

High-dose idarubicin plus busulfan as conditioning regimen to autologous stem cell transplantation: promising post-remission therapy for acute myeloid leukemia in first complete remission?

The optimal post-remission therapy (PRT) for acute myeloid leukemia (AML) remains uncertain. We reported 32 AML patients in first complete remission (CR1) undergoing autologous hematopoietic stem cell transplantation (ASCT) with a characteristic conditioning regimen, termed I-Bu, based on high-dose idarubicin plus busulfan, which considerably strengthened antileukemic activity. Most patients were in better or intermediate-risk group except that cytogenetic or molecular risk information was missing for 18.7 % of the patients. Unpurged peripheral blood stem cells were used in all the cases. The adverse effects were mild and reversible. Only one case of transplant-related mortality was observed. All the patients in this study acquired hematopoietic reconstitution after ASCT. After a median follow-up of 30 (6-119) months, 24 patients (75.0 %) were alive in which 20 (62.5 %) patients were in continuous CR. There were 11 (34.4 %) patients who relapsed after HSCT. Cumulative relapse probability was about 40 % after 24 months. Median OS and DFS have not been reached. Patients in the better and intermediate-risk group had different clinical outcomes, but the differences were not statistically significant. ASCT with I-Bu regimen is possibly promising PRT for better and intermediate-risk AML patients in CR1.

Combined molecular and clinical prognostic index for relapse and survival in cytogenetically normal acute myeloid leukemia

PURPOSE

Cytogenetically normal (CN) acute myeloid leukemia (AML) is the largest and most heterogeneous cytogenetic AML subgroup. For the practicing clinician, it is difficult to summarize the prognostic information of the growing number of clinical and molecular markers. Our purpose was to develop a widely applicable prognostic model by combining well-established pretreatment patient and disease characteristics.

PATIENTS AND METHODS

Two prognostic indices for CN-AML (PINA), one regarding overall survival (OS; PINAOS) and the other regarding relapse-free survival (RFS; PINARFS), were derived from data of 572 patients with CN-AML treated within the AML Cooperative Group 99 study (www.aml-score.org).

RESULTS

On the basis of age (median, 60 years; range, 17 to 85 years), performance status, WBC count, and mutation status of NPM1, CEBPA, and FLT3-internal tandem duplication, patients were classified into the following three risk groups according to PINAOS and PINARFS: 29% of all patients and 32% of 381 responding patients had low-risk disease (5-year OS, 74%; 5-year RFS, 55%); 56% of all patients and 39% of responding patients had intermediate-risk disease (5-year OS, 28%; 5-year RFS, 27%), and 15% of all patients and 29% of responding patients had high-risk disease (5-year OS, 3%; 5-year RFS, 5%), respectively. PINAOS and PINARFS stratified outcome within European LeukemiaNet genetic groups. Both indices were confirmed on independent data from Cancer and Leukemia Group B/Alliance trials.

CONCLUSION

We have developed and validated, to our knowledge, the first prognostic indices specifically designed for adult patients of all ages with CN-AML that combine well-established molecular and clinical variables and that are easily applicable in routine clinical care. The integration of both clinical and molecular markers could provide a basis for individualized patient care through risk-adapted therapy of CN-AML.

Outcome of older patients with acute myeloid leukemia: an analysis of SEER data over 3 decades

BACKGROUND

Acute myeloid leukemia (AML) is the common form of acute leukemia in adults, accounting for over 80% of all acute leukemias in individuals aged >18 years. Overall 5-year survival remains poor in older AML patients; it is <5% in patients aged >65 years. In this study, the authors examined whether survival has improved for subsets of geriatric AML patients over 3 successive decades.

METHODS

Surveillance, Epidemiology and End Results (SEER) data were used to determine trends in relative survival by age among 19,000 patients with AML over 3 successive decades (1977-1986, 1987-1996, and 1997-2006). Relative survival rates (RRs) with 95% confidence intervals (CIs) were calculated as measures of survival.

RESULTS

Overall, the RRs increased for each successive decade (1977-1986, 1987-1996, and 1997-2006) in patients ages 65 to 74 years, with improvements in 12-month survival from 20%, to 25%, to 30%, respectively. Findings were similar for 24-month, 36-month, 48-month, and 60-month survival. However, survival rates did not improve in patients aged ≥75 years. The oldest old patients (aged ≥85 years) had the lowest survival rates, with no apparent improvement.

CONCLUSIONS

This analysis of a large data set demonstrated that, although overall survival remained unsatisfactory among older patients, it improved in the younger old (ages 65-74 years). Survival of older old AML patients has not been favorably impacted by available AML therapies or supportive care, and intervention in this age group is best undertaken on a clinical trial.

Overexpression of GATA1 confers resistance to chemotherapy in acute megakaryocytic Leukemia

It has been previously shown that acute myeloid leukemia (AML) patients with higher levels of GATA1 expression have poorer outcomes. Furthermore, pediatric Down syndrome (DS) patients with acute megakaryocytic leukemia (AMKL), whose blast cells almost universally harbor somatic mutations in exon 2 of the transcription factor gene GATA1, demonstrate increased overall survival relative to non-DS pediatric patients, suggesting a potential role for GATA1 in chemotherapy response. In this study, we confirmed that amongst non-DS patients, GATA1 transcripts were significantly higher in AMKL blasts compared to blasts from other AML subgroups. Further, GATA1 transcript levels significantly correlated with transcript levels for the anti-apoptotic protein Bcl-xL in our patient cohort. ShRNA knockdown of GATA1 in the megakaryocytic cell line Meg-01 resulted in significantly increased cytarabine (ara-C) and daunorubicin anti-proliferative sensitivities and decreased Bcl-xL transcript and protein levels. Chromatin immunoprecipitation (ChIP) and reporter gene assays demonstrated that the Bcl-x gene (which transcribes the Bcl-xL transcripts) is a bona fide GATA1 target gene in AMKL cells. Treatment of the Meg-01 cells with the histone deacetylase inhibitor valproic acid resulted in down-regulation of both GATA1 and Bcl-xL and significantly enhanced ara-C sensitivity. Furthermore, additional GATA1 target genes were identified by oligonucleotide microarray and ChIP-on-Chip analyses. Our findings demonstrate a role for GATA1 in chemotherapy resistance in non-DS AMKL cells, and identified additional GATA1 target genes for future studies.

Hematopoietic transplantation for acute myeloid leukemia with internal tandem duplication of FLT3 gene (FLT3/ITD)

PURPOSE OF REVIEW

Patients with acute myeloid leukemia (AML) traditionally classified as having an intermediate cytogenetic risk [mostly cytogenetically normal AML (CN-AML)] really include a significant proportion of cases with a poor outcome. This is based on the molecular findings at diagnosis, mainly the presence of internal tandem duplication in the FMS-like tyrosine kinase 3 gene(s) (FLT3/ITD). Optimal postremission therapy for these high-risk molecular cases is not well established; as the prognosis is adverse hematopoietic cell transplantation (HCT), mainly allogeneic HCT (allo-HCT), is the most widely accepted strategy.

RECENT FINDINGS

As a rule, patients with FLT3/ITD have a poor outcome with conventional chemotherapy alone. Only patients with an associated nucleophosmin 1 (NPM1) mutation and those with a low mutated-to-wild-type allelic ratio of FLT3/ITD have less unfavorable outcome. Most studies show an advantage of allo-HCT in first complete remission (CR1), with higher 3-5 year disease-free survival and lower relapse risk than with chemotherapy or autologous transplantation (auto-HCT). Regarding allo-HCT proceeding early after reaching CR1 seems to improve survival, rather than after several courses of consolidation chemotherapy.

SUMMARY

Patients with intermediate-risk cytogenetics AML and FLT3/ITD, especially NPM1-wild cases and those NPM1 mutated with a high allelic ratio, should proceed to allo-HCT if possible early after achieving CR1.

Reirradiation in progressive high-grade gliomas: outcome, role of concurrent chemotherapy, prognostic factors and validation of a new prognostic score with an independent patient cohort

Purposes

First, to evaluate outcome, the benefit of concurrent chemotherapy and prognostic factors in a cohort of sixty-four high-grade glioma patients who underwent a second course of radiation therapy at progression. Second, to validate a new prognostic score for overall survival after reirradiation of progressive gliomas with an independent patient cohort.

Patients and methods

All patients underwent fractionated reirradiation with a median physical dose of 36 Gy. Median planned target volume was 110.4 ml. Thirty-six patients received concurrent chemotherapy consisting in 24/36 cases (67%) of carboplatin and etoposide and in 12/36 cases (33%) of temozolomide. We used the Kaplan Meier method, log rank test and proportional hazards regression analysis for statistical assessment.

Results

Median overall survival from the start of reirradiation was 7.7 ± 0.7 months. Overall survival rates at 6 and 12 months were 60 ± 6% and 24 ± 6%, respectively. Despite relatively large target volumes we did not observe any major acute toxicity. Concurrent chemotherapy did not appear to improve outcome. In contrast, female gender, young age, WHO grade III histology, favorable Karnofsky performance score and complete resection of the tumor prior to reirradiation were identified as positive prognostic factors for overall survival. We finally validated a recent suggestion for a prognostic score with our independent but small patient cohort. Our preliminary findings suggest that its ability to discriminate between different prognostic groups is limited.

Conclusions

Outcome of our patients was comparable to previous studies. Even in case of large target volumes reirradiation seems to be feasible without observing major toxicity. The benefit of concurrent chemotherapy is still elusive. A reassessment of the prognostic score, tested in this study, using a larger patient cohort is needed.

Unrelated donor allogeneic transplantation after failure of autologous transplantation for acute myelogenous leukemia: a study from the center for international blood and marrow transplantation research

The survival of patients with relapsed acute myelogenous leukemia (AML) after autologous hematopoietic stem cell transplantation (auto-HCT) is very poor. We studied the outcomes of 302 patients who underwent secondary allogeneic hematopoietic cell transplantation (allo-HCT) from an unrelated donor (URD) using either myeloablative (n = 242) or reduced-intensity conditioning (RIC; n = 60) regimens reported to the Center for International Blood and Marrow Transplantation Research. After a median follow-up of 58 months (range, 2 to 160 months), the probability of treatment-related mortality was 44% (95% confidence interval [CI], 38%-50%) at 1-year. The 5-year incidence of relapse was 32% (95% CI, 27%-38%), and that of overall survival was 22% (95% CI, 18%-27%). Multivariate analysis revealed a significantly better overal survival with RIC regimens (hazard ratio [HR], 0.51; 95% CI, 0.35-0.75; P <.001), with Karnofsky Performance Status score ≥90% (HR, 0.62; 95% CI, 0.47-0.82: P = .001) and in cytomegalovirus-negative recipients (HR, 0.64; 95% CI, 0.44-0.94; P = .022). A longer interval (>18 months) from auto-HCT to URD allo-HCT was associated with significantly lower riak of relapse (HR, 0.19; 95% CI, 0.09-0.38; P <.001) and improved leukemia-free survival (HR, 0.53; 95% CI, 0.34-0.84; P = .006). URD allo-HCT after auto-HCT relapse resulted in 20% long-term leukemia-free survival, with the best results seen in patients with a longer interval to secondary URD transplantation, with a Karnofsky Performance Status score ≥90%, in complete remission, and using an RIC regimen. Further efforts to reduce treatment-related mortaility and relapse are still needed.

High-Dose Cytarabine Consolidation With or Without Additional Amsacrine and Mitoxantrone in Acute Myeloid Leukemia: Results of the Prospective Randomized AML2003 Trial

Purpose

To assess the treatment outcome benefit of multiagent consolidation in young adults with acute myeloid leukemia (AML) in a prospective, randomized, multicenter trial.

Patients and Methods

Between December 2003 and November 2009, 1,179 patients (median age, 48 years; range, 16 to 60 years) with untreated AML were randomly assigned at diagnosis to receive either standard high-dose cytarabine consolidation with three cycles of 18 g/m2 (3× HD-AraC) or multiagent consolidation with two cycles of mitoxantrone (30 mg/m2) plus cytarabine (12 g/m2) and one cycle of amsacrine (500 mg/m2) plus cytarabine (10 g/m2; MAC/MAMAC/MAC). Allogeneic and autologous hematopoietic stem-cell transplantations were performed in a risk-adapted and priority-based manner.

Results

After double induction therapy using a 3 + 7 regimen including standard-dose cytarabine and daunorubicin, complete remission was achieved in 65% of patients. In the primary efficacy population of patients evaluable for consolidation outcomes, consolidation with either 3× HD-AraC or MAC/MAMC/MAC did not result in any significant difference in 3-year overall (69% v 64%; P = .18) or disease-free survival (46% v 48%; P = .99) according to the intention-to-treat analysis. Furthermore, MAC/MAMAC/MAC led to additional GI and hepatic toxicity and a higher rate of infection and bleeding, resulting in significantly shorter 3-year overall survival in the per-protocol analysis compared with 3× HD-AraC (63% v 72%; P = .04).

Conclusion

In younger adults with AML, multiagent consolidation using mitoxantrone and amsacrine in combination with high-dose cytarabine does not improve treatment outcome and confers additional toxicity.

Aberrant Mer receptor tyrosine kinase expression contributes to leukemogenesis in acute myeloid leukemia

Acute myeloid leukemia (AML) continues to be extremely difficult to treat successfully, and the unacceptably low overall survival rates mandate that we assess new potential therapies to ameliorate poor clinical response to conventional therapy. Abnormal tyrosine kinase activation in AML has been associated with poor prognosis and provides strategic targets for novel therapy development. We found that Mer receptor tyrosine kinase was over-expressed in a majority of pediatric (29/36, 80%) and adult (10/10, 100%) primary AML patient blasts at the time of diagnosis, and 100% of patient samples at the time of relapse. Mer was also found to be expressed in 12 of 14 AML cell lines (86%). In contrast, normal bone marrow myeloid precursors expressed little to no Mer. Following AML cell line stimulation with Gas6, a Mer ligand, we observed activation of prosurvival and proliferative signaling pathways, including phosphorylation of ERK1/2, p38, MSK1, CREB, ATF1, AKT and STAT6. To assess the phenotypic role of Mer in AML, two independent short-hairpin RNA (shRNA) constructs were used to decrease Mer expression in the AML cell lines Nomo-1 and Kasumi-1. Reduction of Mer protein levels significantly increased rates of myeloblast apoptosis two to threefold in response to serum starvation. Furthermore, myeloblasts with knocked-down Mer demonstrated decreased colony formation by 67-87%, relative to control cell lines (P<0.01). NOD-SCID-gamma mice transplanted with Nomo-1 myeloblasts with reduced levels of Mer had a significant prolongation in survival compared with mice transplanted with the parental or control cell lines (median survival 17 days in parental and control cell lines, versus 32-36 days in Mer knockdown cell lines, P<0.0001). These data suggest a role for Mer in acute myeloid leukemogenesis and indicate that targeted inhibition of Mer may be an effective therapeutic strategy in pediatric and adult AML.

Autologous Stem Cell Transplantation in elderly Acute Myeloid Leukemia

Treatment outcome in elderly Acute Myeloid Leukemia (AML) is still very disappointing. Although complete remission rate is around 50–60% the 2 years survival is only in the magnitude of 10–20%. This is mainly due to an overrepresentation of adverse prognostic factors present in elderly AML. As relapses emerge from residual disease present after chemotherapy, intensification of treatment could emerge as a rational strategy. Intensification of chemotherapy by increasing the dose of anthracyclines or addition of gemtuzumab ozogamycin (Mylotarg) to standard chemotherapy indeed has proved to be of advantage in elderly AML. In younger AML autologous peripheral blood stem cell transplantation (AuPBSCT) as post remission treatment in comparison to intensive consolidation chemotherapy has been investigated in a few randomized studies. AuPBSCT showed reduced relapse rates with low non-relapse mortality rates. In elderly AML intensification by AuPBSCT also have been performed although randomized studies are lacking. Nevertheless, in the previous years various reports have suggested the potential utility of AuHSCT in AML of the elderly with encouraging results, albeit mostly in highly selected patients. Acceptable toxicity and a relatively low rate of transplant-related mortality has been notified. However relapses occurred which, irrespective of age, still remains the major cause of treatment failure of AuHSCT in AML. In this review we summarize the experience of AuPBSCT in elderly AML.