Patients with t(8;21)(q22;q22) and acute myeloid leukemia have superior failure-free and overall survival when repetitive cycles of high-dose cytarabine are administered

Addition of single dose gemtuzumab ozogamicin to intensive induction chemotherapy in core-binding factor acute myeloid leukemia

In a meta-analysis of 5 trials, the addition of gemtuzumab ozogamicin (GO) to intensive induction chemotherapy led to a survival benefit in patients with core-binding factor (CBF) acute myeloid leukemia (AML). Given the heterogeneous incorporation of GO in clinical trials, the ideal dose and schedule remains unclear. We conducted a single-center retrospective analysis to compare outcomes of patients with CBF-AML treated with intensive induction chemotherapy, with or without a single dose of GO 3 mg/m2, during induction only. We included 87 patients (GO=32, control=55). The composite complete remission (cCR) rate was higher in the control group (93%) compared to the GO group (82%) (p<0.001). The rate of measurable residual disease (MRD) negative cCR, by flow cytometry, was similar between both groups. There were no significant differences between the two groups in terms of toxicity. The 3-year relapse-free survival (RFS) for both groups was similar (71% vs 68%, p=0.5). The 3-year overall survival (OS) for the GO group was 68%, compared to 66% for the control group (p=0.9).In multivariable analysis, age and MRD positive status were risk factors for inferior outcomes. We find that survival of patients with CBF-AML is favorable in the real-world setting. The addition of single-dose GO, during induction, did not lead to a higher remission rate or survival benefit, when compared to intensive chemotherapy without GO. Further investigation into the incorporation of GO in the treatment algorithm for CBF-AML is needed.

The core concepts of core binding factor acute myeloid leukemia: Current considerations for prognosis and treatment

Core binding factor acute myeloid leukemia (CBF AML), defined by t(8;21) or inv(16), is a subset of favorable risk AML. Despite its association with a high complete remission rate after induction and relatively good prognosis overall compared with other subtypes of AML, relapse risk after induction chemotherapy remains high. Optimizing treatment planning to promote recurrence free survival and increase the likelihood of survival after relapse is imperative to improving outcomes. Recent areas of research have included evaluation of the role of gemtuzumab in induction and consolidation, the relative benefit of increased cycles of high dose cytarabine in consolidation, the utility of hypomethylating agents and kinase inhibitors, and the most appropriate timing of stem cell transplant. Surveillance with measurable residual disease testing is increasingly being utilized for monitoring disease in remission, and ongoing investigation seeks to determine how to use this tool for early identification of patients who would benefit from proceeding to transplant. In this review, we outline the current therapeutic approach from diagnosis to relapse while highlighting the active areas of investigation in each stage of treatment.

Acute leukemias in pregnant women: Results of a retrospective study at a local tertiary-care hospital in Japan

Leukemia may rarely develop in a woman during pregnancy, posing clinical challenges to the patient, fetus, family, and medical staff managing malignancy and pregnancy. We retrospectively analyzed cases of pregnancy-associated leukemia consecutively diagnosed and treated at a local tertiary-care hospital in Nagano, Japan, over the past 20 years. Five cases were identified among 377,000 pregnancies in the area (one in every 75,000 pregnancies), all involving acute leukemia (three acute myelogenous leukemia [AML] and two acute lymphoblastic leukemia [ALL]). The cases were diagnosed in the first trimester (n = 1), second trimester (n = 3), or third trimester (n = 1). There were no apparent pregnancy-associated delays in diagnosing and treating the cases. Three patients underwent induction chemotherapy during pregnancy, two of whom eventually delivered healthy babies. One of the five patients chose abortion before chemotherapy initiation. Two cases showing high-risk features at the diagnosis (AML with an FLT3-ITD mutation [n = 1] and relapsed ALL [n = 1]) eventually died despite consolidative allogeneic hematopoietic stem cell transplantation. Our results suggested that patients with pregnancy-associated acute leukemia can be treated similarly to nonpregnant patients, although pregnancy imposes particular clinical challenges that should be resolved with multidisciplinary care.

Acute Myeloid Leukaemia With Translocation (8;21) Masquerading as Peripheral Blood Eosinophilia Having Dysplastic Features: A Diagnostic Challenge

Eosinophilia with a modest number of blasts (<20%) in the peripheral blood and bone marrow smears raises suspicion for myeloproliferative neoplasms (MPNs) and acute myeloid leukaemia (AML). Here, we present a case of AML in a 16-year-old boy who presented with high-grade fever, respiratory distress, and generalised weakness. Marked eosinophilia with dysplastic features and occasional blasts were found in the peripheral blood. In view of dysplastic eosinophils and occasional blasts in peripheral blood, a bone marrow examination was requested which revealed increased eosinophils and their progenitors with dysplasia and a modest number of blast cells (<20%). The bone marrow findings suggest MPNs, which were eventually identified as AML having translocation (8;21) with the aid of immunophenotyping and cytogenetic studies. Eosinophilia and its phenotypic anomalies are rarely found in peripheral blood smears of AML patients with translocation (8;21) which may have been related to the leukaemic process.

Retrospective comparison of survival and responses to Fludarabine, Cytarabine, GCSF (FLAG) in combination with gemtuzumab ozogamicin (GO) or Idarubicin (IDA) in patients with newly diagnosed core binding factor (CBF) acute myelogenous leukemia: MD Anderson experience in 174 patients

Fludarabine, cytarabine, GCSF (FLAG)-based induction/consolidation results in high remission rates in core binding factor (CBF) acute myelogenous leukemia. We treated 174 consecutive patients with newly diagnosed CBF-AML in a prospective clinical trial of FLAG-based induction/consolidation in combination with gemtuzumab ozogamicin (FLAG-GO; N = 65) or in combination with idarubicin (FLAG-IDA; N = 109). The 5 year RFS in the FLAG-GO cohort was significantly better than the FLAG-IDA cohort, 78% versus 59%, respectively (p-value = .02). In multivariate analysis for RFS, age (p = .0001), FLAG-GO regimen (p = .04), 4 log reduction in CBF-related fusion transcript by quantitative polymerase chain reaction (qPCR) in bone marrow samples at end of consolidation therapy (p = .03), and additional cytogenetic abnormalities (p = .03) were significant variables. Lower age (p = .0001) and 3 log or more transcript reduction at end of induction (p = .04) were significant variables predicting for better overall survival (OS), while there was strong trend for better OS with FLAG-GO (p = .06) regimen. FLAG-GO regimen was superior in optimal disease specific fusion transcript reduction at end of induction (p = .002), mid-consolidation (p < .01), and end of consolidation (p < .001) therapy. Induction/consolidation with FLAG-GO regimen results in better clinical outcomes in newly diagnosed patients with CBF-AML compared to FLAG-IDA and achieves deeper molecular clearance by qPCR assessment of the fusion transcripts.

Oncology stewardship in acute myeloid leukemia

In recent years, an explosion of novel agents has shifted the treatment paradigm for patients with acute myeloid leukemia. The optimal place in therapy for many of these novel agents remains unknown due to limited guidance from national guidelines and the way these agents were studied prior to entering the market. A critical evaluation of the literature and incorporation of oncology stewardship principles can be helpful in determining an optimal place for these agents while being mindful of the overall cost that is associated with therapies. The purpose of this review is to critically evaluate the efficacy and safety data for five controversial agents and provide examples of the use of stewardship practices in determining their place in the treatment of acute myeloid leukemia.

Autologous stem cell transplantation in favorable-risk acute myeloid leukemia: single-center experience and current challenges

BACKGROUND

Autologous stem cell transplantation (ASCT) has gained growing consideration as a treatment option for favorable-risk acute myeloid leukemia (FR-AML) in first complete remission (CR1), compared with chemotherapy.

MATERIALS AND METHODS

We report the long-term outcomes of 117 consecutive patients with FR-AML fit for intensive chemotherapy diagnosed in our center between 1999 and 2020, who underwent ASCT.

RESULTS

Sixty-five of the 117 were eligible for intensive post-remission treatment, and 42 of those 65 received ASCT. Median follow up was 132 months. Overall survival (OS) and disease-free survival (DFS) were 75% and 76%. Higher doses of CD34 + stem cell infusions negatively impacted DFS in multivariate analysis. Core-binding factor (CBF) leukemia was an independent prognostic factor for improved DFS. No differences based on pre-transplant measurable residual disease (MRD) were observed. In CBF leukemia, 10-year DFS is 72% for MRD-positive patients versus 100% for MRD negative patients.

CONCLUSIONS

ASCT is effective and safe in FR-AML patients. In CBF leukemia, ASCT provides excellent results regardless of achievement of bone marrow MRD negativity. In NPM1-mutated/FLT3-wild type (mNPM1) AML, early molecular response seems to have more impact on prognosis. Prospective investigation of the role of gemtuzumab ozogamicin in this setting is ongoing.

Activity of decitabine as maintenance therapy in core binding factor acute myeloid leukemia

Background

Posttherapy measurable residual disease (MRD) positivity in core binding factor acute myeloid leukemia (CBF‐AML) is associated with shorter relapse‐free survival (RFS). Elimination of MRD measured via quantitative reverse transcription polymerase chain reaction (qRTPCR) for disease specific transcripts can potentially lead to better outcomes in CBF‐AML.

Methods

We prospectively monitored the MRD using qRTPCR and flow cytometry on bone marrow samples in patients with newly diagnosed CBF‐AML who received decitabine (DAC) maintenance therapy after fludarabine/cytarabine/G‐CSF (FLAG)‐based induction/consolidation regimen. Negative qRTPCR (CMR) was defined as fusion transcript <0.01%.

Results

Thirty‐one patients with CBF‐AML including 14 with t(8;21) and 17 with inv(16) received parenteral DAC as maintenance therapy. Fifteen patients (48.3%) had completed FLAG‐based induction/consolidation but with positive MRD (0.35%, range = 0.01%–0.91%) (Group 1). Sixteen patients (51.7%) could not complete recommended consolidations with FLAG‐based regimen (due to older age or complications) and were switched to DAC maintenance (Group 2). In Group 2, eight patients (50%) had undetectable MRD (Group 2A) (all had qRTPCR ≤ 0.01%) and the other eight patients (50%) had residual fusion product by qRTPCR (0.1%, range = 0.02%–0.36%) (Group 2B) prior to starting DAC. Amongst the 23 patients who had a PCR ≥ 0.01% before maintenance therapy (Groups 1 and 2B), 12 patients (52%) attained a CMR as their best response (responders). The median pre‐DAC qRTPCR amongst responders were 0.03% compared to 0.14% in nonresponders (p = .002). The median estimated molecular RFS amongst responders were 93.9 months. At a median follow‐up of 59.3 months (13.2–106 months) from DAC initiation, 16 patients (51.6%) had to be initiated on a second line of therapy (40%, 25%, and 100% patients, respectively, in Groups1, 2A, and 2B). The median estimated time to new treatment between responders was 112.4 versus 5.8 months in nonresponders (hazard ratio = 0.16, 95% confidence interval = 0.04–0.54); however, there were no difference in overall survival between these groups (p = .37).

Conclusion

DAC is an effective maintenance therapy for CBF‐AML patients with persistent fusion transcript at a low level after FLAG‐based regimen. Attainment of CMR with DAC maintenance can lead to long‐term remission in patients who have persistent MRD positive after FLAG‐based regimen or are unable to receive the full course of consolidation therapy.

C11ORF21, a novel RUNX1 target gene, is down-regulated by RUNX1-ETO

The fusion protein RUNX1-ETO is an oncogenic transcription factor generated by t(8;21) chromosome translocation, which is found in FAB-M2-type acute myeloid leukemia (AML). RUNX1-ETO is known to dysregulate the normal RUNX1 transcriptional network, which should involve essential factors for the onset of AML with t(8;21). In this study, we screened for possible transcriptional targets of RUNX1 by reanalysis of public data in silico, and identified C11orf21 as a novel RUNX1 target gene because its expression was down-regulated in the presence of RUNX1-ETO. The expression level of C11orf21 was low in AML patient samples with t(8;21) and in Kasumi-1 cells, which carry RUNX1-ETO. Knockdown of RUNX1-ETO in Kasumi-1 cells restored C11orf21 expression, whereas overexpression of RUNX1 up-regulated C11orf21 expression. In addition, knockdown of RUNX1 in other human leukemia cells without RUNX-ETO, such as K562, led to a decrease in C11orf21 expression. Of note, the C11orf21 promoter sequence contains a consensus sequence for RUNX1 binding and it was activated by exogenously expressed RUNX1 based on our luciferase reporter assay. This luciferase signal was trans-dominantly suppressed by RUNX1-ETO and site-directed mutagenesis of the consensus site abrogated the reporter activity. This study demonstrated that C11orf21 is a novel transcriptional target of RUNX1 and RUNX1-ETO suppressed C11orf21 transcription in t(8;21) AML. Thus, through this in silico approach, we identified a novel transcriptional target of RUNX1, and the depletion of C11orf21, the target gene, may be associated with the onset of t(8;21) AML.

Is the current consolidation regimen for AML evidence-based?

Current standard of care for consolidation therapy for AML varies based on age and induction regimen, among other factors. Many trials have sought to determine the optimal dose, number of cycles, and schedule for consolidation with cytarabine. For AML patients under age 60, mid-dose cytarabine is as effective as high-dose cytarabine, results after 3 or 4 cycles of cytarabine in consolidation are comparable but are both superior to only one cycle, and giving cytarabine every 12 h on days 1, 2, and 3 appears to have the same benefit but less toxicity than cytarabine given on days 1, 3, and 5. For those over age 60, the best dose of cytarabine is unknown, but post-remission therapy appears to improve survival for some patients who achieve remission after standard induction, depending on induction regimen used and MRD status at time of remission.

[Analysis of risk factors of relapse after allogeneic hematopoietic stem cell transplantation in patients with t (8;21) acute myeloid leukemia]

Objective: To investigate the risk factors of relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with t (8;21) acute myeloid leukemia (AML) . Methods: The clinical features of patients with t (8;21) AML who received allo-HSCT between January 2008 and October 2020 in the Hospital of Blood Disease and the Chinese Academy of Medical Sciences were retrospectively analyzed. Univariate and multivariate analyses were performed on the factors that might influence relapse. Results: A total of 73 patients were enrolled. The analysis revealed that, out of the 73 cases, 10 had relapses, with a 3-year cumulative incidence of relapse (CIR) of 15.7% (95% CI 7.3%-26.8%) . The median time of relapse was 9.2 (2.0-47.6) months. Furthermore, 19 cases died, with a 3-year overall survival (OS) of 68.9% (95% CI 56.4%-81.4%) . Compared with the RUNX1-RUNX1T1 at first diagnosis, a ≥ 3-log reduction within 3 months and/or 4-log reduction within 3-12 months can significantly decrease 3-year CIR after HSCT (13.3% vs 57.1%; 5.1% vs 25.0%, both P<0.001) . Cox multivariate analysis showed that high levels of RUNX1-RUNX1T1 (≥1.58%) on the day of transplantation (day 0) [P=0.006; HR=28.849 (95% CI 2.68-310.524) ] and the flow cytometric analysis of blasts ratio in bone marrow ≥60% at first diagnosis [P=0.015; HR=6.64 (95% CI 1.448-30.457) ] were independent risk factors for relapse. Furthermore, no significant difference in the effect of c-Kit and Flt3 gene mutations on relapse after transplantation was observed (P=0.877 and P=0.773, resp) . The flow cytometric analysis of blasts ratio in bone marrow ≥60% at first diagnosis [P<0.001; HR=8.925 (95% CI 2.702-29.476) ] and the number of courses to achieve complete remission ≥ 2[P=0.013; HR=4.495 (95% CI 1.379-14.649) ] were independent risk factors for OS. Conclusion: Both high levels of RUNX1-RUNX1T1 (≥1.58%) on the day of transplantation (day 0) and the ratio of flow cytometric analysis of blasts in bone marrow at first diagnosis increase the chance of t (8;21) AML relapse after allo-HSCT. Detection of the transcription levels of RUNX1-RUNX1T1 after allo-HSCT at different times could help predict the hazard of relapse.

Non-age-related neoplastic loss of sex chromosome correlated with prolonged survival in real-world CBF-AML patients

In this real-world clinical study, in which we determined eligibility for allogenic hematopoietic stem cell transplantation by prognostic factors and minimal residual disease status, we retrospectively evaluated cytogenetic, genetic, and clinical features in 96 patients with core-binding factor acute myeloid leukemia (CBF-AML) including 62 patients with RUNX1/RUNX1T1 and 34 patients with CBFβ/MYH11. Multivariate analyses for 5-year overall survival (OS) in CBF-AML patients revealed that age of 50 years or older (HR: 3.46, 95% CI 1.47-8.11, P = 0.004) and receiving 2 or more induction cycles (HR: 3.55, 95% CI 1.57-8.05, P = 0.002) were independently associated with worse OS and that loss of sex chromosome (LOS) was independently associated with better OS (HR: 0.09, 95% CI 0.01-0.71, P = 0.022). At the time of complete remission, all 21 karyotyped patients with LOS had a normal karyotype. Furthermore, in all 9 patients with LOS who had a mosaic of metaphase cells with and without t(8;21) or inv(16), the metaphase cells without t(8;21)/inv(16) showed a normal karyotype. These results proved that LOS was not age-related and physiological, but rather a neoplastic chromosomal abnormality.

Genetic features and clinical outcomes of patients with isolated and comutated DDX41-mutated myeloid neoplasms

Isolated and comutated DDX41 myeloid neoplasms have different characteristics.

DDX41-mutated AML has a relatively favorable outcome comparable to core binding factor AML.

DDX41 mutations (germline and somatic) are associated with late onset myelodysplastic syndromes/acute myeloid leukemia (MDS/AML). Myeloid neoplasms (MN) with germline predisposition was identified as a distinct category in the 2016 WHO classification revision, including MN with germline DDX41 mutation. We retrospectively analyzed the molecular findings and clinical characteristics of thirty-three DDX41-mutated (mDDX41) patients at our institution. We identified 14 distinct pathogenic DDX41 variants in 32 patients and 8 DDX41 variants of unknown significance (VUS) in 9 patients. Five (16%) patients had a second DDX41 somatic mutation p.R525H and 13 (40%) had at least one additional oncogenic co-mutation in other genes. The median age at the time of diagnosis was 66 years, with male predominance (72%) and the majority of patients had normal cytogenetics (91%). Two-year overall survival (OS) was 86% and 6 (21%) MDS/AML patients with relatively preserved hematopoietic function were observed without further intervention. In comparison to AML patients with prognostically more favorable subtypes [t(8;21), n=27 and inv(16), n=40], mDDX41 patients in our cohort showed similarly favorable OS. Our study highlights that mDDX41-MN patients often have an indolent course and mDDX41-AML has comparable OS to favorable-risk AML.

Consolidation in AML: Abundant opinion and much unknown

Consolidation therapy forms the backbone of post-remission therapy for AML and is uniformly accepted as an integral part of therapy designed to achieve long-term survival. The need for post-remission therapy was initially described over four decades ago and has since undergone many variations in terms of dosage, number of cycles and intensity of therapy. There is much empiricism in the current understanding of consolidation therapy and much that has not been rigorously studied. This review will consider the many aspects of consolidation therapy, focusing on the number of cycles, differences between young and older adults, first and subsequent remission as well as therapy prior to an allogeneic transplant. Emphasis will be given to differentiate strategies that are clearly evidence-based from those that have been incorporated into standard of care while bypassing the need for rigorous data-driven approaches. Finally, consideration will be given to the current ability to assess the minimal measureable residual disease and the impact that this may have on therapeutic paradigms, including superseding many of the time-honored prognostic features.

Core binding factor acute myelogenous leukemia-2021 treatment algorithm

Core binding factor acute myelogenous leukemia (CBF-AML), characterized by the presence of either t(8;21) (q22;q22) or inv(16) (p13q22)/t(16;16), is considered good-risk AML in the context of cytarabine based intensive chemotherapy. Still, outcome can be improved significantly through the effective implementation of available therapeutic measures and appropriate disease monitoring. The incorporation of gemtuzumab ozogamicin into frontline therapy should be standard. Cytarabine based induction/consolidation regimen may be combined with anthracycline (3 + 7 standard) or antimetabolite, fludarabine. Serial quantitative polymerase chain reaction (QPCR) monitoring of unique fusion transcripts allows monitoring for measurable residual disease clearance; this allows for better prognostication and well as treatment modifications.

Acute Myeloid Leukemia: Historical Perspective and Progress in Research and Therapy Over 5 Decades

With the Food and Drug Administration approval of 9 agents for different acute myeloid leukemia (AML) indications, the prognosis and management of AML is evolving rapidly. Herein, we review the important milestones in the history of AML research and therapy, discuss insights regarding prognostic assessment and prediction of treatment outcome, detail practical supportive care measures, and summarize the current treatment landscape and areas of evolving research.

Combination of dasatinib with chemotherapy in previously untreated core binding factor acute myeloid leukemia: CALGB 10801

Acute myeloid leukemia (AML) with either t(8;21)(q22;q22) or inv(16)(p13q22)/t(16;16)(p13;q22) is referred to as core binding factor (CBF) AML. Although categorized as favorable risk, long-term survival for these patients is only ∼50% to 60%. Mutated (mut) or overexpressed KIT, a gene encoding a receptor tyrosine kinase, has been found almost exclusively in CBF AML and may increase the risk of disease relapse. We tested the safety and clinical activity of dasatinib, a multi-kinase inhibitor, in combination with chemotherapy. Sixty-one adult patients with AML and CBF fusion transcripts (RUNX1/RUNX1T1 or CBFB/MYH11) were enrolled on Cancer and Leukemia Group B (CALGB) 10801. Patients received cytarabine/daunorubicin induction on days 1 to 7 and oral dasatinib 100 mg/d on days 8 to 21. Upon achieving complete remission, patients received consolidation with high-dose cytarabine followed by dasatinib 100 mg/d on days 6 to 26 for 4 courses, followed by dasatinib 100 mg/d for 12 months. Fifteen (25%) patients were older (aged ≥60 years); 67% were CBFB/MYH11-positive, and 19% harbored KITmut. There were no unexpected or dose-limiting toxicities. Fifty-five (90%) patients achieved complete remission. With a median follow-up of 45 months, only 16% have relapsed. The 3-year disease-free survival and overall survival rates were 75% and 77% (79% and 85% for younger patients [aged <60 years], and 60% and 51% for older patients). Patients with KITmut had comparable outcome to those with wild-type KIT (3-year rates: disease-free survival, 67% vs 75%; overall survival, 73% vs 76%), thereby raising the question of whether dasatinib may overcome the negative impact of these genetic lesions. CALGB 10801 was registered at www.clinicaltrials.gov as #NCT01238211.

Risk adapted therapeutic strategy in newly diagnosed acute myeloid leukemia: Refining the outcomes of ELN 2017 intermediate-risk patients

INTRODUCTION

Despite advances in the treatment of acute myeloid leukemia (AML), cytotoxic chemotherapy remains the standard induction regimen.

PATIENTS AND METHODS

In this single center retrospective study, we assessed outcomes of 99 consecutive adult AML patients treated with a risk-adapted strategy with a median follow-up of 35.5 months.

RESULTS

We identified 24 (24 %), 55 (56 %) and 20 (20 %) patients classified as favorable-, intermediate-, and adverse- risk group respectively, according to the European LeukemiaNet (ELN) 2017 classification. Patients either received idarubicin and cytarabine induction chemotherapy with or without FLT3 inhibitors or hypomethylating agents based on age and comorbidity. The complete response (CR) rate was 76 % (82 % and 61 % in patients aged < 60 and ≥ 60, respectively). For the whole cohort, the 3-year overall survival (OS) was 53 %, being 62 % and 30 % in patients aged < 60 and ≥ 60, respectively. The 3-year leukemia-free survival (LFS) was 54 %, with 56 % and 45 % in patients aged < 60 and ≥ 60, respectively. The 3-year LFS were 58 %, 62 % and 25 % for patients within ELN favorable-, intermediate-, and adverse-risk groups respectively. Twenty-seven (36 %) out of 75 patients with intermediate- and adverse-risk disease underwent allogeneic hematopoietic cell transplantation (allo-HCT) in first CR with 92 % of them receiving post-transplant maintenance consisting of azacitidine in 19 (76 %) patients or sorafenib in 6 (24 %) patients. Of these patients younger than 60 years, the 3-year OS and LFS were 85 % and 69 %, respectively.

CONCLUSION

These results indicate an improved OS for AML patients especially in intermediate-risk category who were treated with a total therapy consisting of induction chemotherapy followed by allo-HCT and post-transplant maintenance.

Role of CD19 and specific KIT-D816 on risk stratification refinement in t(8;21) acute myeloid leukemia induced with different cytarabine intensities

High‐dose cytarabine (Ara‐C) has been reported with increased treatment‐related mortality, whereas few data are available concerning intermediate‐dose Ara‐C for induction of acute myeloid leukemia (AML) with t(8;21) translocation. We retrospectively analyzed factors impacting complete remission (CR), event‐free survival (EFS), cumulative incidence of relapse (CIR), and overall survival (OS) in 197 adults with t(8;21) AML, of whom 107 cases were induced with intermediate‐dose and 90 with standard‐dose Ara‐C (as part of 3 + 7 protocol). After a single induction course, the overall CR rate was 87.6% (170/194), with a significant difference between the standard‐dose (83/105, 79.0%) and intermediate‐dose (87/89, 97.8%) groups (p < 0.001). Rather than general KITmut, the specific KIT‐D816 independently led to a lower probability of achieving CR (HR = 3.29 [1.18–9.24], p = 0.023), worse EFS (HR = 3.53 [1.82–6.84], p < 0.001), and OS (HR = 5.45 [1.77–16.84], p = 0.003) in the standard‐dose group, but not in the intermediate‐dose group. CD19(+) represented the only independent factor predicting lower CIR both in the standard‐dose group (HR = 0.32 [0.10–1.00], p = 0.050) and in the intermediate‐dose group (HR = 0.11 [0.03–0.40], p = 0.001). When combined, KIT(+) plus CD19(−) conferred the most increased relapse risk (3‐year CIR 60%; SE 0.12). Specific KIT‐D816, instead of general KITmut, may be incorporated in prognostication model for t(8;21) AML. Combination of CD19 with KIT provides a more definite risk stratification profile for t(8;21) AML.

Postremission therapy with repeated courses of high-dose cytarabine, idarubicin, and limited autologous stem cell support achieves a very good long-term outcome in European leukemia net favorable and intermediate-risk acute myeloid leukemia

Consolidation treatment in acute myeloid leukemia (AML) patients achieving complete remission (CR) is warranted. High-dose cytarabine (HDAC) is considered first choice in favorable risk and an option in intermediate-risk AML. However, its optimal dose and schedule, as well as the benefit of additional chemotherapy agents remain controversial. Herein, we report on the long-term outcome of consecutive unselected AML patients treated with repeated courses of HDAC, with the addition of idarubicin, followed by autologous peripheral blood stem cell (PBSC) support, in order to limit toxicity, according to Northern Italy Leukemia Group (NILG) AML-01/00 study (EUDRACT number 00400673). Among 338 patients consecutively diagnosed from 2001 to 2017 at our center, 148 with high-risk AML (adverse cytogenetic, isolated FLT3-internal tandem duplication mutation, refractory to first induction) were addressed to allogeneic stem cell transplant. All other cases, 186 patients (55%), median age 53 (range 19-75), were considered standard-risk and received the NILG AML-01/00 program. After achieving CR, patients were mobilized with cytarabine 8 g/sqm to collect autologous CD34+-PBSC and received three consolidation cycles with HDAC (20 g/sqm) plus idarubicin (20 mg/sqm) per cycle, followed by reinfusion of limited doses of CD34+ PBSC (1-2x106/kg). The program was completed by 160 (86%) patients. Toxicity was acceptable. Neutrophils recovered a median of 10 days. Treatment-related mortality was 3/160 (1.8%). After a median follow-up of 66.4 months, overall survival (OS) and relapse-free survival (RFS) at 5-years were 61.4% and 52.4%, respectively. Twenty-eight selected patients aged >65 had similar outcomes. According to European leukemia net-2010 classification, the OS and RFS at 5-years were 76.4% and 65% in favorable risk, without differences between molecular subgroups, 52.3% and 47.2% in Intermediate-I, 45.2% and 36.5% in Intermediate-II risk patients, respectively. In conclusion, consolidation including repeated courses of high dose cytarabine and idarubicin, with limited PBSC support, proved feasible and very effective in nonhigh risk patients. The incorporation of novel agents in its backbone may be tested to further improve patient's prognosis.

High expression of PSF1 promotes drug resistance and cell cycle transit in leukemia cells

Escape of cancer cells from chemotherapy is a problem in the management of cancer patients. Research on chemotherapy resistance has mainly focused on the heterogeneity of cancer cells, multiple gene mutations, and quiescence of malignant cancer cells. However, some studies have indicated that interactions between cancer cells and vascular cells promote resistance to chemotherapy. Here, we established mouse leukemia models using the cell lines THP‐1 or MEG‐1. These were derived from acute and chronic myeloid leukemias, respectively, and highly expressed DNA replication factor PSF1, a member of the GINS complex. We found that, after anti‐cancer drug administration, surviving GFP‐positive leukemia cells in the bone marrow were located adjacent to blood vessels, as previously reported in a subcutaneous solid tumor transplantation model. Treating THP‐1 and MEG‐1 cells with anti‐cancer drugs in vitro revealed that those most strongly expressing PSF1 were most chemoresistant, suggesting that PSF1 induces not only cell cycle progression but also facilitates cell survival. Indeed, when PSF1 expression was suppressed by shRNA, the growth rate was reduced and cell death was enhanced in both cell lines. Furthermore, PSF1 knockdown in leukemia cells led to a change in their location at a distance from the blood vessels in a bone marrow transplantation model. These findings potentially reflect a mechanism of escape of leukemic cells from chemotherapy and suggest that PSF1 may be a possible therapeutic target to enhance the effect of chemotherapy.

Post-remission therapy of adults aged 60 and older with acute myeloid leukemia in first complete remission: role of treatment intensity on the outcome

Although complete remission (CR) is achieved in 50 to 70% of older fit patients with acute myeloid leukemia (AML), consolidation therapy in this age group remains challenging. In this retrospective study, we aimed to compare outcome in elderly patients treated with different post-remission modalities, including allogenic and autologous hematopoietic stem cell transplantation (HSCT), intensive chemotherapy, and standard-dose chemotherapy (repeated 1 + 5 regimen). We collected data of 441 patients ≥ 60 years in first CR from a single institution. Median age was 67 years. Sixty-one (14%) patients received allo-HSCT, 51 (12%) auto-HSCT, 70 (16%) intensive chemotherapy with intermediate- or high-dose cytarabine (I/HDAC), and 190 (43%) 1 + 5 regimen. Median follow-up was 6.5 years. In multivariate analysis, allo-HSCT, cytogenetics, and PS had a significant impact on OS and LFS. In spite of a more favorable-risk profile, the patients who received I/HDAC had no significantly better LFS as compared with patients treated with 1 + 5 (median LFS 8.8 months vs 10.6 months, p = 0.96). In transplanted patients, median LFS was 13.3 months for auto-HSCT and 25.8 months for allo-HSCT. Pre-transplant chemotherapy with I/HDAC had no effect on the outcome. Toxicity was significantly increased for both transplanted and non-transplanted patients treated with I/HDAC, with more units of blood and platelet transfusion and more time spent in hospitalization, but no higher non-relapse mortality. This study shows that post-remission chemotherapy intensification is not associated with significantly better outcome as compared with standard-dose chemotherapy in elderly patients for whom, overall results remain disappointing.

Clinical heterogeneity under induction with different dosages of cytarabine in core binding factor acute myeloid leukaemia

Repeated cycles of post-remission high-dose cytarabine (Ara-C) have been suggested to improve survival in core binding factor (CBF) acute myeloid leukaemia (AML). High-dose Ara-C used for induction regimens has also been reported to be associated with increased treatment-related mortality (TRM). Few data are available about intermediate-dose Ara-C serving as induction therapy. The aim of our study was to compare the tolerance and outcomes of standard- and intermediate-dose levels of Ara-C as induction in CBF AML and to analyse the clinical heterogeneity of the two AML entities under these induction settings. We retrospectively investigated the outcomes in adults with CBF AML induced with regimens based on standard-dose Ara-C at 100 to 200 mg/m² or intermediate-dose Ara-C at 1,000 mg/m². In total, 152 patients with t(8; 21) and 54 patients with inv(16) AML were administered an induction regimen containing anthracyclines plus either standard- or intermediate-dose Ara-C. After a single course of induction, the complete remission (CR) rate in the inv(16) cohort was 52/52 (100%), higher than the 127/147 (86.4%) in the t(8; 21) cohort (P = 0.005). Intermediate-dose Ara-C (HR = 9.931 [2.135-46.188], P = 0.003) and negative KITmut (HR = 0.304 [0.106-0.874], P = 0.027) independently produced an increased CR rate in the t(8; 21) cohort. Positive CD19 expression (HR = 0.133 [0.045-0.387], P = 0.000) and sex (male) (HR = 0.238 [0.085-0.667], P = 0.006) were associated with superior leukaemia-free survival (LFS) in the t(8; 21) cohort independently of KITmut status or the induction regimen. We conclude that intermediate-dose Ara-C is superior to standard-dose Ara-C for induction of remission in t(8; 21) AML, and CD19 status and sex independently confer prognostic significance for LFS. The KITmut status alone does not have an independent effect on survival in t(8; 21) AML. More intensive induction therapy is unnecessary in inv(16) AML.

Loss of the Y chromosome predicts a high relapse risk in younger adult male patients with t(8;21) acute myeloid leukemia on high-dose cytarabine consolidation therapy: a retrospective multicenter study

The prognostic significance of loss of the Y chromosome (LOY) in patients with t(8;21)(q22;q22) acute myeloid leukemia (AML) remains poorly understood. To investigate this issue, 226 younger adult male patients with t(8;21) AML from 15 Chinese hematology research centers were retrospectively evaluated, among which, 50.4% had LOY. In patients receiving high-dose cytarabine (HiDAC) consolidation therapy, LOY was associated with a significantly higher cumulative incidence of relapse (CIR, HR = 2.18, p = .048), worse relapse-free survival (RFS, HR = 2.39, p = .026), and worse but not significant overall survival (OS, HR = 2.71, p = .166). A multivariate analysis adjusted for age, WBC, KIT mutations, and minimal residual disease showed LOY to be an independent adverse prognostic factor for relapse in patients on HiDAC consolidation therapy. Our results suggest that LOY may be associated with a high relapse risk in t(8;21) AML patients receiving HiDAC therapy during consolidation.

Mutations associated with a 17-gene leukemia stem cell score and the score's prognostic relevance in the context of the European LeukemiaNet classification of acute myeloid leukemia

Leukemia stem cells (LSC) are more resistant to standard chemotherapy and their persistence during remission can cause relapse, which is still one of the major clinical challenges in the treatment of acute myeloid leukemia (AML). A better understanding of the mutational patterns and the prognostic impact of molecular markers associated with stemness could lead to better clinical management and improve patients’ outcomes. We applied a previously described 17-gene expression score comprising genes differently expressed between LSC and leukemic bulk blasts, for 934 adult patients with de novo AML, and studied associations of the 17-gene LSC score with clinical data and mutation status of 81 genes recurrently mutated in cancer and leukemia. We found that patients with a high 17-gene score were older and had more mutations. The 17-gene score was found to have a prognostic impact in both younger (aged <60 years) and older (aged ≥60 years) patients with AML. We also analyzed the 17-gene LSC score in the context of the 2017 European LeukemiaNet genetic-risk classification and found that for younger patients the score refined the classification, and identified patients currently classified in the European LeukemiaNet Favorable-risk category who had a worse outcome.

Acute myeloid leukemia with t(8;21)(q22;q22.1)/RUNX1-RUNX1T1 and KIT Exon 8 mutation is associated with characteristic mastocytosis and dismal outcomes

KIT mutations are observed in about 20-40% of acute myeloid leukemia with t(8;21)(q22;q22.1)/RUNX1-RUNX1T1 [abbreviated AML t(8;21) here] with mutations involving exon 17 being the most common. Despite high frequencies of KIT mutations in both AML t(8;21) and systemic mastocytosis (SM), AML t(8;21) associated with SM is uncommon, and restricted to KIT exon 17 mutated cases. In this study, we report two cases of AML t(8;21) associated SM that KIT mutation occurred in exon 8 (T417_D419delinsY). In both patients, the bone marrow displayed increased round/ovoid mast cells with bilobated nuclei and absence of CD2 and CD25 expression. RUNX1/RUNX1T1 fusion was shown in both myeloblasts and mast cells by FISH. Patient #1 was refractory to induction chemotherapy and died at day 50; patient #2 had residual AML, marked SM, and persistent RUNX1/RUNX1T1 fusion after induction therapy.

Eosinophilia in acute myeloid leukemia: Overlooked and underexamined

The presence of eosinophilia in acute myeloid leukemia (AML) suggests an underlying core binding factor (CBF) lesion, a platelet derived growth factor (PDGFR) translocation, or another rare translocation (such as ETV6-ABL1). Each of these cytogenetic entities carries unique diagnostic, prognostic, and therapeutic implications. CBF AML is most common and as such, its treatment is more clearly established, consisting of intensive induction chemotherapy followed by cytarabine based consolidation. Due in large part to its intrinsic chemo-sensitivity, CBF AML is associated with relatively high rates of remission and survival. PDGFR mediated AML is comparatively rare, and as such, diagnostic and treatment paradigms are not as well defined. Early identification of PDGFR translocations is essential, as they confer profound imatinib sensitivity which may, in many instances, spare the need for chemotherapy. Prompt recognition of such lesions requires a strong index of suspicion, and as such these diagnoses are often initially overlooked. Unfortunately, many cases of PDGFR associated AML, particularly those with other concurrent cytogenetic abnormalities, demonstrate treatment emergent imatinib resistance. Such patients continue to present a challenge, even with the advent of novel tyrosine kinase inhibitors (TKIs). Patients with rare translocations such as ETV6-ABL1 are not well described however seem to follow an aggressive clinical course, with limited response to imatinib, and poor outcomes. This review examines the significance of eosinophilia in the context of AML, with respect to its presentation, pathology, and cytogenetics, and with special attention to appropriate evaluation and treatment.

Clinical implications of molecular markers in acute myeloid leukemia

The recently updated World Health Organization (WHO) Classification of myeloid neoplasms and leukemia reflects the fact that research in the underlying pathogenic mechanisms of acute myeloid leukemia (AML) has led to remarkable advances in our understanding of the disease. Gene mutations now allow us to explore the enormous diversity among cytogenetically defined subsets of AML, particularly the large subset of cytogenetically normal AML. Despite the progress in unraveling the tumor genome, only a small number of recurrent mutations have been incorporated into risk-stratification schemes and have been proven to be clinically relevant, targetable lesions. We here discuss the utility of molecular markers in AML in prognostication and treatment decision making, specifically highlighting the aberrations included in the current WHO classification.

Molecular remission at the end of treatment is a necessary goal for a good outcome in ELN favorable-risk acute myeloid leukemia: a real-life analysis on 201 patients by the Rete Ematologica Lombarda network

Favorable acute myeloid leukemia (AML) patients (pts.) demonstrate a relatively good outcome with standard induction; thus, pts. are generally not addressed to allogeneic transplant in first remission. However, it is not clear if also in a real-life setting, the outcome is homogeneous in the different favorable molecular groups and which are the parameters significantly associated to an increased relapse risk, useful to suggest the need of an intensified approach. In order to clarify this point, we collected clinical data on consecutive unselected AML pts. assigned to favorable category (modified ELN 2010 due to the inclusion of double-mutated CEBPA-positive cases), diagnosed and treated in six centers of the Italian network Rete Ematologica Lombarda (REL) from 2007 to 2015. We assessed response (CR, mCR), relapse rate (CIR), and outcome (OS, DFS) after first-line treatment. A total of 201 pts. was studied and the analysis was performed globally and in each molecular group: t(8;21)(q22;q22)/RUNX1-RUNX1T1 (30 pts., 14.9%), inv. (16)(p13q22) or t(16;16)(p13q22)/CBFB-MIH11 (35 pts., 17.4%), normal karyotype and mutated NPM1 and negative FLT3-ITD (116 pts., 57.7%) or double-mutated CEBPA (CEBPAdm) (20 pts., 10%). Complete remission (CR) was obtained in 188 pts. (93.5%), molecular CR (mCR) in 114 (67.5%); After a median follow-up of 2.4 years, cumulative incidence of relapse (CIR) was documented in 78 of 188 responding pts. (41%) after a median time of 11.3 months. CIR was higher in the CBFB-MIH11 group, in pts. achieving only a hematological response without mCR (72.1 vs 28.1%, p < 0.001), in older pts. and it resulted independently associated with a lower median cytarabine cumulative dose (CCD). Median OS was not reached: after 5 years it was 66.3%, and median DFS was 5.3 years, both without difference among groups. Molecular CR reached at any time, during or after the end of first-line treatment, was significantly associated with better DFS, and in particular, mCR assessed at the end of treatment was confirmed in multivariate analysis as an independent prognostic factor both for DFS and OS. In conclusion, the present study confirms in a real-life context the overall good prognosis of favorable-risk AML; the achievement of any molecular negativity during first-line treatment, particularly when assessed at the end of treatment, is associated with lower relapse and better survival. Increasing age at diagnosis has a negative prognostic impact, while CCD higher than 18 g/sqm is associated with better outcome.

Amyloid precursor protein has clinical and prognostic significance in AML1-ETO-positive acute myeloid leukemia

Amyloid precursor protein (APP) has been reported to be highly expressed in acute myeloid leukemia (AML)1-eight-twenty one (ETO)-positive AML. In the present study, the clinical and prognostic significance of APP expression was assessed in 65 patients with AML1-ETO-positive AML using reverse transcription-quantitative polymerase chain reaction. The patients were divided into an APP-high expression (APP-H) group (n=32) and an APP-low expression (APP-L) group (n=33) according to the cut-off value of APP relative expression, which was calculated by receiver operating characteristic curve analysis. It was observed that C-KIT mutations (14/32 vs. 3/33, P=0.009), white blood cell count (median, 23.2×10⁹ vs. 12.4×10⁹ cells/l; P=0.011) and bone marrow cellularity (median, 91.0 vs. 84.0%; P=0.039) and incidence of extramedullary leukemia (11/32 vs. 3/33, P=0.013) were all significantly increased in the APP-H group compared with the APP-L group. Furthermore, significantly lower rate of cumulative two-cycle complete remission (83.9 vs. 100%, P=0.016), major molecular remission following two courses of consolidation (34.5 vs. 71.4%, P=0.005), and poorer relapse-free survival (RFS) (33.5±5.2% vs. 76.3±6.9%, P<0.001) and overall survival (OS) (44.5±7.0% vs. 81.9±5.8%, P=0.002) were associated with APP overexpression. Multivariate analysis revealed that APP overexpression was a significant adverse factor affecting both RFS and OS. Taken together, these data suggest that APP may be correlated with C-KIT mutations and involved in leukemia cell proliferation, and its overexpression has an adverse effect on the prognosis in AML1-ETO-positive AML.

Minimal residual disease eradication with epigenetic therapy in core binding factor acute myeloid leukemia

Recurrent translocations, t(8;21) or inv(16), in core binding factor acute myeloid leukemia (CBF-AML) are amenable to monitoring for minimal residual disease (MRD) with reverse transcriptase polymerase chain reaction (RTPCR). Despite a favorable prognosis, disease relapse remains the single cause of treatment failure in CBF-AML. Fusion products of these translocations recruit epigenetic silencing complexes resulting in hematopoietic maturation arrest. We hypothesized that maintenance therapy with hypomethylating agents (HMA), including decitabine (DAC) and azacitidine (AZA) after induction/consolidation, can be used for MRD elimination to ultimately prolong relapse free survival. Real-time quantitative (RTPCR) trends were reviewed in 23 patients (median age 53 years) with CBF-AML that received HMA therapy following induction/consolidation with fludarabine, cytarabine, and G-CSF (FLAG) with low dose gemtuzumab or idarubicin (NCT00801489). Of the 23 patients evaluated, 17 had a detectable RTPCR at HMA initiation. Five patients had progressive disease and a notable increase in RTPCR values over 1-2 cycles of HMA therapy. Twelve patients did not fail HMA and had a median RTPCR at HMA initiation of 0.06 (range, 0.01-0.91). Unlike the HMA failure subset, 11 of these patients had a reduction in RTPCR after the first or second cycle of HMA. Our data suggests that CBF-AML patients with low levels of RTPCR (between 0.01 and 0.05) at the conclusion of induction/consolidation chemotherapy benefit most from maintenance HMA, particularly those that have a reduction in the RTPCR within the first two cycles of HMA therapy.

Timed sequential therapy for acute myelogenous leukemia: Results of a retrospective study of 301 patients and review of the literature

Timed sequential therapy (TST) aims to improve outcomes in acute myelogenous leukemia (AML) by harnessing drug-induced cell cycle kinetics of AML, where a second drug is timed to coincide with peak leukemia proliferation induced by the first drugs. We analyzed outcomes in 301 newly diagnosed AML patients treated from 2004-2013 with cytarabine, anthracycline, and etoposide TST induction. Median age was 52 (range 20-74) and complete remission rate 68%. With median follow-up 5.8 years, 5-year DFS and overall survival (OS) were 37% (95% CI 31-45%) and 32% (95% CI 27-38%), respectively. In multivariate analysis, older age, unfavorable cytogenetics, and WBC≥50×10⁹/L resulted in worse OS. Among patients not undergoing blood and marrow transplant, a propensity score analysis, which reduces imbalance in baseline characteristics, showed consolidation with TST compared with 1 or more cycles high-dose cytarabine trended toward lower DFS and post-remission survival with hazard ratio (HR) 1.9 (95% CI 0.9-4.0), and 1.6 (95% CI 0.7-3.6), respectively. Our results demonstrate the efficacy and feasibility of TST induction for newly diagnosed patients with AML, with results comparable to that seen in clinical trials with other TST therapies and 7+3.

Sharing post-AML consolidation supportive therapy with local centers reduces patient travel burden without compromising outcomes

Acute myeloid leukemia (AML) is frequently treated with induction and consolidation chemotherapy. Consolidation chemotherapy can be delivered on an ambulatory basis, requiring some patients to travel long distances for treatment at specialized centers. We developed a shared care model where patients receive consolidation chemotherapy at a quaternary center, but post-consolidation supportive care at local hospitals. To evaluate the impact of our model on patient travel and outcomes we conducted a retrospective analysis of AML and acute promyelocytic leukemia patients receiving consolidation over four years at our quaternary center. 73 patients received post-consolidation care locally, and 344 at the quaternary center. Gender, age and cytogenetic risk did not significantly differ between groups. Shared care patients saved mean round trip distance of 146.5km±99.6 and time of 96.7min±63.4 compared to travelling to quaternary center. There was no significant difference in overall survival between groups, and no increased hazard of death for shared care patients. 30, 60, and 90day survival from start of consolidation was 98.6%, 97.2%, and 95.9% for shared care and 98.8%, 97.1%, and 95.3% for quaternary center patients. Thus, a model utilizing regional partnerships for AML post-consolidation care reduces travel burden while maintaining safety.

Epigenetic Silencing of Eyes Absent 4 Gene by Acute Myeloid Leukemia 1-Eight-twenty-one Oncoprotein Contributes to Leukemogenesis in t(8;21) Acute Myeloid Leukemia

Background:

The acute myeloid leukemia 1 (AML1)-eight-twenty-one (ETO) fusion protein generated by the t(8;21)(q22;q22) translocation is considered to display a crucial role in leukemogenesis in AML. By focusing on the anti-leukemia effects of eyes absent 4 (EYA4) gene on AML cells, we investigated the biologic and molecular mechanism associated with AML1-ETO expressed in t(8;21) AML.

Methods:

Qualitative polymerase chain reaction (PCR), quantitative reverse transcription PCR (RT-PCR), and Western blotting analysis were used to observe the mRNA and protein expression levels of EYA4 in cell lines. Different plasmids (including mutant plasmids) of dual luciferase reporter vector were built to study the binding status of AML1-ETO to the promoter region of EYA4. Chromatin immunoprecipitation assay was used to study the epigenetic silencing mechanism of EYA4. Bisulfite sequencing was applied to detect the methylation status in EYA4 promoter region. The influence of EYA4 gene in the cell proliferation, apoptosis, and cell clone-forming ability was detected by the technique of Cell Counting Kit-8, flow cytometry, and clonogenic assay.

Results:

EYA4 gene was hypermethylated in AML1-ETO⁺ patients and its expression was down-regulated by 6-fold in Kasumi-1 and SKNO-1 cells, compared to HL-60 and SKNO-1-siA/E cells, respectively. We demonstrated that AML1-ETO triggered the epigenetic silencing of EYA4 gene by binding at AML1-binding sites and recruiting histone deacetylase 1 and DNA methyltransferases. Enhanced EYA4 expression levels inhibited cellular proliferation and suppressed cell colony formation in AML1-ETO⁺ cell lines. We also found EYA4 transfection increased apoptosis of Kasumi-1 and SKNO-1 cells by 1.6-fold and 1.4-fold compared to negative control, respectively.

Conclusions:

Our study identified EYA4 gene as targets for AML1-ETO and indicated it as a novel tumor suppressor gene. In addition, we provided evidence that EYA4 gene might be a novel therapeutic target and a potential candidate for treating AML1-ETO⁺ t (8;21) AML.

Randomized Phase II Study of Clofarabine-Based Consolidation for Younger Adults With Acute Myeloid Leukemia in First Remission

Purpose To evaluate the efficacy and safety of a clofarabine-based combination (CLARA) versus conventional high-dose cytarabine (HDAC) as postremission chemotherapy in younger patients with acute myeloid leukemia (AML). Patients and Methods Patients age 18 to 59 years old with intermediate- or unfavorable-risk AML in first remission and no identified donor for allogeneic stem-cell transplantation (SCT) were eligible. Two hundred twenty-one patients were randomly assigned to receive three CLARA or three HDAC consolidation cycles. The primary end point was relapse-free survival (RFS). To handle the confounding effect of SCT that could occur in patients with late donor identification, hazard ratios (HRs) of events were adjusted on the time-dependent treatment × SCT interaction term. Results At 2 years, RFS was 58.5% (95% CI, 49% to 67%) in the CLARA arm and 46.5% (95% CI, 37% to 55%) in the HDAC arm. Overall, 110 patients (55 in each arm) received SCT in first remission. On the basis of a multivariable Cox-adjusted treatment × SCT interaction, the HR of CLARA over HDAC before or in absence of SCT was 0.65 (95% CI, 0.43 to 0.98; P = .041). In a sensitivity analysis, when patients who received SCT in first remission were censored at SCT time, 2-year RFS was 53.3% (95% CI, 39% to 66%) in the CLARA arm and 31.0% (95% CI, 19% to 43%) in the HDAC arm (HR, 0.63; 95% CI, 0.41 to 0.98; P = .043). Gain in RFS could be related to the lower cumulative incidence of relapse observed in the CLARA arm versus the HDAC arm (33.9% v 46.4% at 2 years, respectively; cause-specific HR, 0.61; 95% CI, 0.40 to 0.94; P = .025). CLARA cycles were associated with higher hematologic and nonhematologic toxicity than HDAC cycles. Conclusion These results suggest that CLARA might be considered as a new chemotherapy option in younger patients with AML in first remission.

Molecular biomarkers in acute myeloid leukemia

Acute myeloid leukemia (AML) is the most common acute leukemia in adults. The pathophysiology of this disease is just beginning to be understood at the cellular and molecular level, and currently cytogenetic markers are the most important for risk stratification and treatment of AML patients. However, with the advent of new technologies, the detection of other molecular markers such as point mutations and characterization of epigenetic and proteomic profiles, have begun to play an important role in how the disease is approached. Recent evidence shows that the identification of new AML biomarkers contributes to a better understanding of the molecular basis of the disease, is significantly useful in screening, diagnosis, prognosis and monitoring of AML, as well as the possibility of predicting each individual's response to treatment. This review summarizes the most relevant molecular (genetic, epigenetic, and protein) biomarkers associated with acute myeloid leukemia and discusses their clinical importance in terms of risk prediction, diagnosis and prognosis.

Scientific Achievements May Not Reach Everyone: Understanding Disparities in Acute Leukemia

Over the past decade, scientific advancements have resulted in improved survival from acute leukemia. Continued advancements are expected given the attention to precision medicine and the resulting growth in development and adoption of risk-stratified, personalized therapies. While precision medicine has great potential to improve acute leukemia outcomes, there remain significant barriers to ensuring equitable access to these technologies and receipt of these prescribed targeted, personalized therapies. Over the past 3 years, studies report persistent outcome disparities among patients from specific racial and ethnic backgrounds, insurance and socioeconomic status, and other socio-demographic factors after a diagnosis of acute leukemia. A few recent studies examine etiologies for acute leukemia disparities and highlight the importance of ensuring access and equitable delivery of scientific advancements. In the context of continued scientific progress, future strategies require thoughtfully considered improvements in the delivery of care that can overcome the current challenges our patients face.

Acute myeloid leukemia--major progress over four decades and glimpses into the future

In this Review, the progress in research and therapy of acute myeloid leukemia is detailed.

Clinical Impact of Additional Cytogenetic Aberrations, cKIT and RAS Mutations, and Treatment Elements in Pediatric t(8;21)-AML: Results From an International Retrospective Study by the International Berlin-Frankfurt-Münster Study Group

PURPOSE

This retrospective cohort study aimed to determine the predictive relevance of clinical characteristics, additional cytogenetic aberrations, and cKIT and RAS mutations, as well as to evaluate whether specific treatment elements were associated with outcomes in pediatric t(8;21)-positive patients with acute myeloid leukemia (AML).

PATIENTS AND METHODS

Karyotypes of 916 pediatric patients with t(8;21)-AML were reviewed for the presence of additional cytogenetic aberrations, and 228 samples were screened for presence of cKIT and RAS mutations. Multivariable regression models were used to assess the relevance of anthracyclines, cytarabine, and etoposide during induction and overall treatment. End points were the probability of achieving complete remission, cumulative incidence of relapse (CIR), probability of event-free survival, and probability of overall survival.

RESULTS

Of 838 patients included in final analyses, 92% achieved complete remission. The 5-year overall survival, event-free survival, and CIR were 74%, 58%, and 26%, respectively. cKIT mutations and RAS mutations were not significantly associated with outcome. Patients with deletions of chromosome arm 9q [del(9q); n = 104] had a lower probability of complete remission (P = .01). Gain of chromosome 4 (+4; n = 21) was associated with inferior CIR and survival (P < .01). Anthracycline doses greater than 150 mg/m(2) and etoposide doses greater than 500 mg/m(2) in the first induction course and high-dose cytarabine 3 g/m(2) during induction were associated with better outcomes on various end points. Cumulative doses of cytarabine greater than 30 g/m(2) and etoposide greater than 1,500 mg/m(2) were associated with lower CIR rates and better probability of event-free survival.

CONCLUSION

Pediatric patients with t(8;21)-AML and additional del(9q) or additional +4 might not be considered at good risk. Patients with t(8;21)-AML likely benefit from protocols that have high doses of anthracyclines, etoposide, and cytarabine during induction, as well as from protocols comprising cumulative high doses of cytarabine and etoposide.

Is it time to change conventional consolidation chemotherapy for acute myeloid leukemia in CR1?

PURPOSE OF REVIEW

Choosing the most appropriate postremission therapy (PRT) for a patient with acute myeloid leukemia (AML) in first complete remission remains a challenging task. Factors such as risk for disease relapse, nonrelapse mortality associated with different PRT approaches, donor availability, prospects for salvage should disease relapse, and patient preference all affect PRT choice.

RECENT FINDINGS

New genetic markers refine AML risk stratification and identify patients within the 'classical' risk groups who may benefit from transplant-based or chemotherapy-based PRT. The use of minimal residual disease in first remission to guide PRT choice and the application of novel, targeted therapies have the potential to alter PRT approaches across AML risk groups. The advent of alternative donor sources, use of reduced intensity regimens, and improved supportive care all affect the availability and safety of transplant-based PRT and challenge the relevance of the older legacy 'donor/no-donor' genetically randomized trials.

SUMMARY

Genetic risk assessment, monitoring of minimal residual disease in first remission, use of targeted agents, and the newer transplant strategies all have the potential to 'personalize' PRT choice in the AML patient. The clinical value of these novel interventions awaits validation in prospective, risk-adapted clinical trials.

High expression of c-kit mRNA predicts unfavorable outcome in adult patients with t(8;21) acute myeloid leukemia

The reason that a certain subgroup of acute myeloid leukemia (AML) patients with t(8;21) translocation (generating the AML1/ETO fusion gene) displays a poor survival remains elusive. The proto-oncogene c-kit is expressed in approximately 80% of AML cases. The kinase domain mutation of the c-kit gene, one of the most common gain-of-function mutations associated with t(8;21) AML, predicts higher relapse risk and poor prognosis. However, the role of c-kit high expression in t(8;21) AML remains poorly understood. Here we evaluated the prognostic significance of c-kit expression levels in AML patients. The mRNA expression of c-kit was determined by real-time quantitative reverse transcription PCR in 132 adult AML patients. Patients were grouped into quartiles according to c-kit expression levels (Q1–Q4, each quartile containing 25% of patients) and divided into c-kit high (Q4; n = 33) and c-kit low (Q1–Q3; n = 99). High c-kit expression was associated with AML1/ETO-positive and with c-kit mutation. Of note, 35.8% of the AML1/ETO-positive AML patients carrying wild-type c-kit expressed high levels of c-kit, suggesting that other factors are involved in c-kit overexpression. High c-kit expression was associated with inferior overall and event-free survival in AML1/ETO-positive patients and was independently predictive for overall and event-free survival in multivariate analyses in a c-kit mutation-independent manner. Thus, high c-kit expression serves as a reliable molecular marker for poor prognosis, supporting a pathogenetic role of c-kit signaling in AML1/ETO-positive AML. AML1/ETO-positive patients with high c-kit expression might benefit from early treatment modifications and molecular target therapies.