Effect of priming with granulocyte colony-stimulating factor on the outcome of chemotherapy for acute myeloid leukemia

Effectiveness and safety of granulocyte colony-stimulating factor priming regimen for acute myeloid leukemia: A systematic review and meta-analysis of the Clinical Practice Guideline for the use of G-CSF 2022 from the Japan Society of Clinical Oncology

BACKGROUND

The outcomes of relapsed or refractory acute myeloid leukemia (AML) remain poor. Although the concomitant use of granulocyte colony-stimulating factor (G-CSF) and anti-chemotherapeutic agents has been investigated to improve the antileukemic effect on AML, its usefulness remains controversial. This study aimed to investigate the effects of G-CSF priming as a remission induction therapy or salvage chemotherapy.

METHODS

We performed a thorough literature search for studies related to the priming effect of G-CSF using PubMed, Ichushi-Web, and the Cochrane Library. A qualitative analysis of the pooled data was performed, and risk ratios (RRs) with confidence intervals (CIs) were calculated and summarized.

RESULTS

Two reviewers independently extracted and accessed the 278 records identified during the initial screening, and 62 full-text articles were assessed for eligibility in second screening. Eleven studies were included in the qualitative analysis and 10 in the meta-analysis. A systematic review revealed that priming with G-CSF did not correlate with an improvement in response rate and overall survival (OS). The result of the meta-analysis revealed the tendency for lower relapse rate in the G-CSF priming groups without inter-study heterogeneity [RR, 0.91 (95% CI 0.82-1.01), p = 0.08; I2 = 4%, p = 0.35]. In specific populations, including patients with intermediate cytogenetic risk and those receiving high-dose cytarabine, the G-CSF priming regimen prolonged OS.

CONCLUSIONS

G-CSF priming in combination with intensive remission induction treatment is not universally effective in patients with AML. Further studies are required to identify the patient cohort for which G-CSF priming is recommended.

Improving long-term outcomes with intensive induction chemotherapy for patients with AML

Intensive chemotherapy in combination with allogeneic hematopoietic cell transplantation and supportive care can induce long-term remissions in around 50% of acute myeloid leukemia patients eligible for intensive treatment. Several treatment optimization trials helped to refine schedule and dosing of the historic "7 + 3" combination. Together with the addition of novel agents, increased efficacy and tolerability led to improved long-term outcomes. Unsatisfactory outcomes in fit elderly patients and unfavorable genetic subgroups have raised the question of whether less-intensive venetoclax-based approaches may be beneficial as an alternative. Although tempting and worth exploring, this issue will remain controversial until the results of randomized comparisons appear. To date, intensive chemotherapy remains the only evident curative treatment option for long-term disease eradication in a fixed treatment time. With the advent of more novel agents and advances in minimal residual disease (MRD) detection and maintenance approaches, the face of intensive treatment could change in many ways. Several are being explored in clinical trials, such as (1) combinations of more than 1 novel agent with the intensive backbone, (2) head-to-head comparisons of novel agents, (3) replacement or dose reduction of cytotoxic components such as anthracyclines, and (4) MRD-guided escalation and de-escalation strategies. The combination of intensive treatment with individualized tailored innovative strategies will most certainly reduce treatment-related toxicities and increase the chances for long-term remission in the future.

Outcomes of adult patients with type 1 primary refractory acute myeloid leukemia: a single center experience

Adult patients with newly diagnosed de novo acute myeloid leukemia (AML), who had less than a 50% reduction in blast numbers and with > 15% residual blasts after first cycle of induction chemotherapy, defined as type 1 primary refractory (REF1), have grave prognosis. We retrospectively analyzed the data of 58 patients with REF1 who received salvage treatments with curative intension to evaluate the impact of salvage regimens with regard to response and overall survival (OS). Seventeen patients received intermediate- or high-dose cytarabine (ID/HD Ara-C) based intensive salvage chemotherapy, 36 patients received G-CSF primed less intensive chemotherapy and 5 patients received novel targeted drugs based low intensive therapy. The CR/CRi and MLFS rate was 6/17 and 2/17, 14/36 and 3/36, 3/5 and 0/5, respectively. The median OS for the whole cohort was 20.3 months. Median OS was comparable between the 3 arms. Overall, 42 patients underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT), 14 patients in the intensive arm, 24 patients in the less intensive arm and 4 patients in the low intensive arm. Median survival for allo-HSCT patients was significantly longer than for non-allo-HSCT patients (38.8 months vs. 2.1 months, p < 0.001). In multivariate analysis, achievement of CR/CRi after the salvage regimen were predictive of OS. We conclude that no significant difference in outcome among traditional salvage regimens in patients with REF1. G-CSF primed less intensive chemotherapy could serve as an alternative of ID/HD Ara-C based intensive chemotherapy and allo-HSCT is indispensable for long-term survival.

CAG (cytarabine, aclarubicin and granulocyte colony-stimulating factor) regimen for core binding factor acute myeloid leukaemia with measurable residual disease

Acute myeloid leukaemia (AML) with t (8;21) or inv (16), called core binding factor (CBF) AML, has a favourable prognosis. However, some CBF-AML patients have persistent measurable residual disease (MRD) and are more likely to relapse after standard chemotherapy treatment. The CAG regimen, composed of cytarabine, aclarubicin and granulocyte colony-stimulating factor, has been proven to be effective and safe in treating refractory AML patients. We performed a retrospective study to evaluate the efficacy of the CAG regimen to eliminate MRD detected by RUNX1::RUNX1T1 and CBFβ::MYH11 transcript levels by quantitative polymerase chain reaction (Q-PCR) among 23 patients. Molecular response was defined as the ratio of fusion transcript after treatment to that before treatment less than or equal to 0.5. The molecular response rate and median decrease ratio of fusion transcripts at the molecular level of the CAG regimen were 52% and 0.53, respectively. The median fusion transcripts before CAG treatment was 0.25% whereas after CAG was 0.11%. Among the 15 patients who had a poor molecular response to the high/intermediate-dose cytarabine regimen, the median decrease ratios of transcripts at the molecular level of high/intermediate-dose cytarabine and CAG were 1.55 and 0.53 (P = 0.028), respectively, and 6 of 15 patients achieved a molecular response to CAG (40%). The median disease-free survival was 18 months, and the overall survival rate at 3 years among all patients was 72.7% ± 10.7%. The common grades 3-4 adverse events were nausea (100%), thrombocytopenia (39%) and neutropenia (37.5%). The CAG regimen may have activity in CBF-AML patients and could provide a new option for patients who have a poor molecular response to high/intermediate-dose cytarabine.

Comparative efficacy and safety of eleven induction chemotherapy regimens for young adult patients with newly diagnosed acute myeloid leukemia: a network meta-analysis

The optimal induction chemotherapy regimens for young adult patients with newly diagnosed acute myeloid leukemia (AML) are not well-defined since the lack of direct comparisons between emerging treatments. Network meta-analysis (NMA) is a statistical tool to integrate direct and indirect evidence to evaluate the effect of multiple interventions. Thus, we conducted an NMA to systematically assess the efficacy and safety of different inductions for these patients. PubMed, Embase, Cochrane Library, and Web of Science were searched from establishment to 2020-03-11. Randomized controlled trials (RCTs) using different inductions were included. We deemed 11 trials eligible, including 11 inductions with 5052 participants. Relative risk (RR) and 95% confidence intervals (CIs) were calculated. In terms of complete remission (CR) rate, DAC ranked highest and was significantly higher than IA (RR = 1.27, 95% CI (1.09-1.48)) and DA (RR = 1.28, 95% CI (1.13-1.46)) (p < 0.05). The ranking of DA + Pioglitazone was second only to that of DAC, followed by HAA. For early mortality, HAD, HAA, and DA + GO were significantly higher than DA/IA (p < 0.05). DAC and DA + Pioglitazone showed similar early mortality compared to DA/IA (p > 0.05). Regarding incidence of early grade 3-4 infection, no significant differences between interventions were observed. To conclude, among the included 11 induction regimens, DAC was potentially the top choice for young adult patients with newly diagnosed AML, with highest CR rate, low early mortality, and incidence of early infection. DA + Pioglitazone and HAA also showed a superiority over the others to achieve higher CR rate, while caution should be kept in mind due to the higher early mortality of HAA.

Increased survival disparities among children and adolescents & young adults with acute myeloid leukemia: A Dutch population-based study

For many cancers, adolescents and young adults (AYAs) have a poorer prognosis than pediatric patients. Our study evaluates survival outcomes of children (0‐17 years) and AYAs (18‐39 years) diagnosed with acute myeloid leukemia (AML) in the Netherlands between 1990 and 2015 (N = 2058) utilizing the population‐based Netherlands Cancer Registry, which includes information on therapy and site of primary treatment. Five‐ and 10‐year relative (disease‐specific) survival were estimated for all patients, children and AYAs. Multivariable analyses were performed using generalized linear models (excess mortality) and logistic regression (early mortality). AYAs with AML had a substantially lower 5‐ and 10‐year relative survival than children (5‐year: 43% vs 58%; 10‐year: 37% vs 51%). The gap in 5‐year relative survival was largest (nearly 20 percent‐points) in 2010 to 2015, despite survival improvements over time across all ages. The multivariable‐adjusted excess risk of dying was 60% higher in AYAs (95% CI: 37%‐86%). Early mortality (death within 30 days of diagnosis) declined over time, and did not differ between children and AYAs. In conclusion, AYAs diagnosed with AML in the Netherlands had a worse prognosis than pediatric patients. The survival gap seemed most pronounced in recent years, suggesting that improvements in care resulting in better outcome for children have not led to equal benefits for AYAs.

Long-term outcomes following the addition of granulocyte colony-stimulating factor-combined high-dose cytarabine to total body irradiation and cyclophosphamide conditioning in single-unit cord blood transplantation for myeloid malignancies

An intensified myeloablative conditioning regimen, involving the addition of granulocyte colony-stimulating factor (G-CSF)-combined high-dose cytarabine (12 g/m²) to standard total body irradiation and cyclophosphamide, has been performed for adult patients with myeloid malignancies in single-unit cord blood transplantation (CBT) since 1998 in our institute. We update the results of CBT, as the first allogeneic hematopoietic cell transplantation after this conditioning regimen, in 169 patients with a median long-term follow-up of 10.4 years. The median age was 43 years (range, 16 to 59 years). Ninety-four patients (56%) were in non-remission at the time of CBT, and 124 patients (73%) were acute myeloid leukemia. The median cryopreserved cord blood total nucleated cell dose and CD34⁺ cell dose was 2.40 × 10⁷/kg and 0.93 × 10⁵/kg, respectively. The cumulative incidence of neutrophil recovery at 42 days was 94.4% (95% confidence interval [CI]: 88.6-97.3%). Among the whole cohort, 105 patients were still alive at the end of the study period. The cumulative incidences of relapse and non-relapse mortality at 10 years were 26.0% (95% CI: 19.5-33.0%) and 16.9% (95% CI: 11.4-23.4%), respectively. There was an overall survival probability of 62.5% (95% CI: 54.3-69.7%) at 10 years. Higher disease risk index alone significantly affected higher overall mortality (hazard ratio 2.21, P = 0.003) in multivariate analysis. These outcomes demonstrate that G-CSF-combined myeloablative conditioning could have favorable long-term remission rates for adult patients with myeloid malignancies undergoing single-unit CBT.

Leukaemia: a model metastatic disease

In contrast to solid cancers, which often require genetic modifications and complex cellular reprogramming for effective metastatic dissemination, leukaemic cells uniquely possess the innate ability for migration and invasion. Dedifferentiated, malignant leukocytes retain the benign leukocytes' capacity for cell motility and survival in the circulation, while acquiring the potential for rapid and uncontrolled cell division. For these reasons, leukaemias, although not traditionally considered as metastatic diseases, are in fact models of highly efficient metastatic spread. Accordingly, they are often aggressive and challenging diseases to treat. In this Perspective, we discuss the key molecular processes that facilitate metastasis in a variety of leukaemic subtypes, the clinical significance of leukaemic invasion into specific tissues and the current pipeline of treatments targeting leukaemia metastasis.

Sex disparity in acute myeloid leukaemia with FLT3 internal tandem duplication mutations: implications for prognosis

Incidence, molecular presentation and outcome of acute myeloid leukaemia (AML) are influenced by sex, but little attention has been directed at untangling sex‐related molecular and phenotypic differences between female and male patients. While increased incidence and poor risk are generally associated with a male phenotype, the poor prognostic FLT3 internal tandem duplication (FLT3‐ITD) mutation and co‐mutations with NPM1 and DNMT3A are overrepresented in female AML. Here, we have investigated the relationship between sex and FLT3‐ITD mutation status by comparing clinical data, mutational profiles, gene expression and ex vivo drug sensitivity in four cohorts: Beat AML, LAML‐TCGA and two independent HOVON/SAKK cohorts, comprising 1755 AML patients in total. We found prevalent sex‐associated molecular differences. Co‐occurrence of FLT3‐ITD, NPM1 and DNMT3A mutations was overrepresented in females, while males with FLT3‐ITDs were characterized by additional mutations in RNA splicing and epigenetic modifier genes. We observed diverging expression of multiple leukaemia‐associated genes as well as discrepant ex vivo drug responses, suggestive of discrete functional properties. Importantly, significant prognostication was observed only in female FLT3‐ITD‐mutated AML. Thus, we suggest optimization of FLT3‐ITD mutation status as a clinical tool in a sex‐adjusted manner and hypothesize that prognostication, prediction and development of therapeutic strategies in AML could be improved by including sex‐specific considerations.

Granulocyte colony-stimulating factor directly acts on mouse lymphoid-biased but not myeloid-biased hematopoietic stem cells

Granulocyte colony-stimulating factor (G-CSF) is widely used in clinical settings to mobilize hematopoietic stem cells (HSC) into the circulation for HSC harvesting and transplantation. However, whether G-CSF directly stimulates HSC to change their cell cycle state and fate is controversial. HSC are a heterogeneous population consisting of different types of HSC, such as myeloid-biased HSC and lymphoid-biased HSC. We hypothesized that G-CSF has different effects on different types of HSC. To verify this, we performed serum-free single-cell culture and competitive repopulation with cultured cells. Single highly purified HSC and hematopoietic progenitor cells (HPC) were cultured with stem cell factor (SCF), SCF + G-CSF, SCF + granulocyte/macrophage (GM)-CSF, or SCF + thrombopoietin (TPO) for 7 days. Compared with SCF alone, SCF + G-CSF increased the number of divisions of cells from the lymphoid-biased HSCenriched population but not that of cells from the My-bi HSC-enriched population. SCF + G-CSF enhanced the level of reconstitution of lymphoidbiased HSC but not that of myeloid-biased HSC. Clonal transplantation assay also showed that SCF + G-CSF did not increase the frequency of myeloid-biased HSC. These data showed that G-CSF directly acted on lymphoid- biased HSC but not myeloid-biased HSC. Our study also revised the cytokine network at early stages of hematopoiesis: SCF directly acted on myeloid-biased HSC; TPO directly acted on myeloid-biased HSC and lymphoid- biased HSC; and GM-CSF acted only on HPC. Early hematopoiesis is controlled differentially and sequentially by a number of cytokines.

FLT3-ITD mutations in acute myeloid leukaemia - molecular characteristics, distribution and numerical variation

Recurrent somatic internal tandem duplications (ITD) in the FMS-like tyrosine kinase 3 (FLT3) gene characterise approximately one third of patients with acute myeloid leukaemia (AML), and FLT3-ITD mutation status guides risk-adapted treatment strategies. The aim of this work was to characterise FLT3-ITD variant distribution in relation to molecular and clinical features, and overall survival in adult AML patients. We performed two parallel retrospective cohort studies investigating FLT3-ITD length and expression by cDNA fragment analysis, followed by Sanger sequencing in a subset of samples. In the two cohorts, a total of 139 and 172 mutant alleles were identified in 111 and 123 patients, respectively, with 22% and 28% of patients presenting with more than one mutated allele. Further, 15% and 32% of samples had a FLT3-ITD total variant allele frequency (VAF) < 0.3, while 24% and 16% had a total VAF ≥ 0.7. Most of the assessed clinical features did not significantly correlate to FLT3-ITD numerical variation nor VAF. Low VAF was, however, associated with lower white blood cell count, while increasing VAF correlated with inferior overall survival in one of the cohorts. In the other cohort, ITD length above 50 bp was identified to correlate with inferior overall survival. Our report corroborates the poor prognostic association with high FLT3-ITD disease burden, as well as extensive inter- and intrapatient heterogeneity in the molecular features of FLT3-ITD. We suggest that future use of FLT3-targeted therapy could be accompanied with thorough molecular diagnostics and follow-up to better predict optimal therapy responders.

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

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

A phase I trial evaluating the effects of plerixafor, G-CSF, and azacitidine for the treatment of myelodysplastic syndromes

Interactions between the bone marrow microenvironment and MDS tumor clones play a role in pathogenesis and response to treatment. We hypothesized G-CSF and plerixafor may enhance sensitivity to azacitidine in MDS. Twenty-eight patients with MDS were treated with plerixafor, G-CSF and azacitidine with a standard 3 + 3 design. Subjects received G-CSF 10 mcg/kg D1-D8, plerixafor D4-D8, and azacitidine 75 mg/m² D4-D8, but the trial was amended to reduce G-CSF dose to 5 mcg/kg for 5 days after 2 patients had significant leukocytosis. Plerixafor was dose escalated to 560 mcg/kg/day without dose limiting toxicity. Two complete responses and 6 marrow responses were seen for an overall response rate (ORR) of 36% in evaluable patients, and ORR of 53% in patients receiving the triplet. Evidence of mobilization correlated with a higher ORR, 60% vs. 17%. Plerixafor, G-CSF and azacitidine appears tolerable when given over 5 days and has encouraging response rates.KEY POINTSPlerixafor and G-CSF can be safely combined with azacitidine for 5 days in patients with MDS.The overall response rate of 53% for evaluable patients with this regimen is higher than expected and more responses were seen in patients with blast mobilization.

Efficacy and cost-benefit of filgrastim administered after early assessment bone marrow biopsy during induction therapy for acute myeloid leukemia

The role of filgrastim during acute myeloid leukemia (AML) induction therapy remains controversial. At our institution, newly diagnosed AML patients from 2003 through 2019 were retrospectively evaluated. Patients were stratified on whether they received filgrastim within 5 days after early assessment bone marrow (BMBx) and divided into early GCSF group (eGCSF) and no-eGCSF group. A total of 121 patients were included. We found significantly shorter hospital stay (median 24 vs 26 days, p < .01), absolute neutrophil count recovery days (median 23 vs 25 days, p = .03), and intravenous antibiotics days (mean 18.5 vs 21.4 days, p = .01) in patients with eGCSF comparing with no-eGCSF. There was no significant difference regarding complete response rates; however, for those failed to achieve remission, eGCSF was associated with higher blast count. There was no significant difference regarding overall survival or progression-free survival. The use of eGCSF was associated with cost savings of $5199 per patient over no-eGCSF.

DYRK1A regulates B cell acute lymphoblastic leukemia through phosphorylation of FOXO1 and STAT3

DYRK1A is a serine/threonine kinase encoded on human chromosome 21 (HSA21) that has been implicated in several pathologies of Down syndrome (DS), including cognitive deficits and Alzheimer's disease. Although children with DS are predisposed to developing leukemia, especially B cell acute lymphoblastic leukemia (B-ALL), the HSA21 genes that contribute to malignancies remain largely undefined. Here, we report that DYRK1A is overexpressed and required for B-ALL. Genetic and pharmacologic inhibition of DYRK1A decreased leukemic cell expansion and suppressed B-ALL development in vitro and in vivo. Furthermore, we found that FOXO1 and STAT3, transcription factors that are indispensable for B cell development, are critical substrates of DYRK1A. Loss of DYRK1A-mediated FOXO1 and STAT3 signaling disrupted DNA damage and ROS regulation, respectively, leading to preferential cell death in leukemic B cells. Thus, we reveal a DYRK1A/FOXO1/STAT3 axis that facilitates the development and maintenance of B-ALL.

Randomised controlled trial of conditioning regimen for cord blood transplantation for adult myeloid malignancies comparing high-dose cytarabine/cyclophosphamide/total body irradiation with versus without G-CSF priming: G-CONCORD study protocol

INTRODUCTION

A better long-term quality of life after umbilical cord blood transplantation (CBT) is observed compared with transplants from other alternative donors, whereas graft failure and relapses after CBT are still major issues. To minimise graft failure and relapse after CBT, intensification of conditioning by the addition of high-dose cytosine arabinoside (CA) and concomitant continuous use of granulocyte-colony stimulating factor (G-CSF) are reported to convey a significantly better survival after CBT in some retrospective studies. To confirm the effect of G-CSF plus CA combination, in addition to the standard conditioning regimen, cyclophosphamide (CY)/total body irradiation (TBI), we design a randomised controlled study comparing CA/CY/TBI with versus without G-CSF priming (G-CSF combined conditioned cord blood transplantation [G-CONCORD] study).

METHODS AND ANALYSIS

This is a multicentre, open-label, randomised phase III study that aimed to compare G-CSF+CA/CY/TBI as a conditioning regimen for CBT with CA/CY/TBI. Patients with acute myeloid leukaemia or myelodysplastic syndrome, aged 16-55 years, are eligible. The target sample size is 160 and the registration period is 4 years. The primary endpoint is the 2-year disease-free survival rate after CBT. The secondary endpoints are overall survival, relapse, non-relapse mortality, acute and chronic graft-versus-host disease, engraftment rate, time to neutrophil recovery, short-term adverse events, incidence of infections and causes of death.This study employs a single one-to-one web-based randomisation between the with-G-CSF versus without-G-CSF groups after patient registration. Combination of high-dose CA and CY/TBI in both groups is used for conditioning.

ETHICS AND DISSEMINATION

The study protocol was approved by the central review board, Nagoya University Certified Review Board, after the enforcement of the Clinical Trials Act in Japan. The manuscripts presenting data from this study will be submitted for publication in quality peer-reviewed medical journals. Study findings will be disseminated via presentations at national/international conferences and peer-reviewed journals.

TRIAL REGISTRATION NUMBERS

UMIN000029947 and jRCTs041180059.

Kindlin-3 loss curbs chronic myeloid leukemia in mice by mobilizing leukemic stem cells from protective bone marrow niches

Kindlin-3 (K3)-mediated integrin adhesion controls homing and bone marrow (BM) retention of normal hematopoietic cells. However, the role of K3 in leukemic stem cell (LSC) retention and growth in the remodeled tumor-promoting BM is unclear. We report that loss of K3 in a mouse model of chronic myeloid leukemia (CML) triggers the release of LSCs from the BM into the circulation and impairs their retention, proliferation, and survival in secondary organs, which curbs CML development, progression, and metastatic dissemination. We found de novo expression of cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) on CML-LSCs but not normal hematopoietic stem cells and this enabled us to specifically deplete K3 with a CTLA-4-binding RNA aptamer linked to a K3-siRNA (small interfering RNA) in CTLA-4⁺ LSCs in vivo, which mobilized LSCs in the BM, induced disease remission, and prolonged survival of mice with CML. Thus, disrupting interactions of LSCs with the BM environment is a promising strategy to halt the disease-inducing and relapse potential of LSCs.

Targeting CXCR4 in AML and ALL

The interaction of acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) blasts with the bone marrow microenvironment regulates self-renewal, growth signaling, as well as chemotherapy resistance. The chemokine receptor, CXC receptor 4 (CXCR4), with its ligand chemokine ligand 12 (CXCL12), plays a key role in the survival and migration of normal and malignant stem cells to the bone marrow. High expression of CXCR4 on AML and ALL blasts has been shown to be a predictor of poor prognosis for these diseases. Several small molecule inhibitors, short peptides, antibodies, and antibody drug conjugates have been developed for the purposes of more effective targeting and killing of malignant cells expressing CXCR4. In this review we will discuss recent results and strategies in targeting CXCR4 with these agents in patients with AML or ALL.

Stromal cell protein kinase C-β inhibition enhances chemosensitivity in B cell malignancies and overcomes drug resistance

Overcoming drug resistance remains a key challenge to cure patients with acute and chronic B cell malignancies. Here, we describe a stromal cell-autonomous signaling pathway, which contributes to drug resistance of malignant B cells. We show that protein kinase C (PKC)-β-dependent signals from bone marrow-derived stromal cells markedly decrease the efficacy of cytotoxic therapies. Conversely, small-molecule PKC-β inhibitors antagonize prosurvival signals from stromal cells and sensitize tumor cells to targeted and nontargeted chemotherapy, resulting in enhanced cytotoxicity and prolonged survival in vivo. Mechanistically, stromal PKC-β controls the expression of adhesion and matrix proteins, required for activation of phosphoinositide 3-kinases (PI3Ks) and the extracellular signal-regulated kinase (ERK)-mediated stabilization of B cell lymphoma-extra large (BCL-XL) in tumor cells. Central to the stroma-mediated drug resistance is the PKC-β-dependent activation of transcription factor EB, regulating lysosome biogenesis and plasma membrane integrity. Stroma-directed therapies, enabled by direct inhibition of PKC-β, enhance the effectiveness of many antileukemic therapies.

Insulin-like growth factor (IGF) signaling in T-cell acute lymphoblastic leukemia

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive cancer, characterized by an uncontrolled expansion and accumulation of T-cell progenitors. During leukemic progression, immature T cells grow abnormally and occupy the bone marrow compartment, thereby interfering with the production of normal blood cells. Pediatric T-ALL is curable with intensive chemotherapy, but there are significant, long-term side effects and ~20% of patients suffer relapse for which there are limited treatment options. Adult T-ALL in contrast is largely incurable and refractory/relapsed disease is common despite multi-agent chemotherapy (5-year overall survival of ~40%), and thus new therapeutic targets are needed. We have reported previously on the role of insulin-like growth factor (IGF) signaling in T-ALL, and shown that it exerts potent phenotypes in both leukemia stem cell and bulk tumor cell populations. Modulators of IGF signaling may thus prove useful in improving outcomes in patients with T-ALL. In this review, we summarize the most recent findings relating to IGF signaling in T-ALL and outline therapeutic options using clinically relevant IGF signaling modulators.

Remission clone in acute myeloid leukemia shows growth advantage after chemotherapy but is distinct from leukemic clone

In a previously published case study of acute myeloid leukemia, we tracked the dynamics of somatic mutations over 9 years. Interestingly, we observed a group of mutations that expanded during remission, which we named the "remission clone." To determine the nature of the remission clones, we performed flow cytometry-based cell sorting followed by ultradeep sequencing. The remission clone repeatedly expanded after chemotherapeutic cycles and was suppressed during relapse in the myeloid lineage (multipotent hematopoietic stem, progenitor, and myeloid cells). On the other hand, the remission clone was consistently observed in lymphoid lineages (B and T cells) regardless of the disease state. When transfected into the HEK-293 cell line, the NR2C2(A93V) mutant exhibited a growth advantage (all p values < 0.05). The results indicate that the remission clone seems to be another form of clonal hematopoiesis, but without a clear association with leukemia. As the remission clone is present in both myeloid and lymphoid lineages, it likely originates from ancestral hematopoietic cell lineages. More importantly, the remission clone is distinct from the leukemic clone; therefore, mutations expanded during remission require special interpretation when performing next-generation sequencing-based measurable residual disease assessment.

Ecological principle meets cancer treatment: treating children with acute myeloid leukemia with low-dose chemotherapy

Standard chemotherapy regimens for remission induction of pediatric acute myeloid leukemia (AML) are associated with significant morbidity and mortality. We performed a cohort study to determine the impact of reducing the intensity of remission induction chemotherapy on the outcomes of selected children with AML treated with a low-dose induction regimen plus granulocyte colony stimulating factor (G-CSF) (low-dose chemotherapy (LDC)/G-CSF). Complete response (CR) after two induction courses was attained in 87.0% (40/46) of patients receiving LDC/G-CSF. Post-remission therapy was offered to all patients, and included standard consolidation and/or stem cell transplantation. During the study period, an additional 94 consecutive children with AML treated with standard chemotherapy (SDC) for induction (80/94 (85.1%) of the patients attained CR after induction II, P = 0.953) and post-remission. In this non-randomized study, there were no significant differences in 4-year event-free (67.4 vs. 70.7%; P = 0.99) and overall (70.3 vs. 74.6%, P = 0.69) survival in the LDC/G-CSF and SDC cohorts, respectively. After the first course of induction, recovery of white blood cell (WBC) and platelet counts were significantly faster in patients receiving LDC/G-CSF than in those receiving SDC (11.5 vs. 18.5 d for WBCs (P < 0.001); 15.5 vs. 22.0 d for platelets (P < 0.001)). To examine the quality of molecular response, targeted deep sequencing was performed. Of 137 mutations detected at diagnosis in 20 children who attained hematological CR after two courses of LDC/G-CSF (n = 9) or SDC (n = 11), all of the mutations were below the reference value (variant allelic frequency <2.5%) after two courses, irrespective of the treatment group. In conclusion, children with AML receiving LDC/G-CSF appear to have similar outcomes and mutation clearance levels, but significantly lower toxicity than those receiving SDC. Thus, LDC/G-CSF should be further evaluated as an effective alternative to remission induction in pediatric AML.

Clonal hematopoiesis of indeterminate potential and its impact on patient trajectories after stem cell transplantation

Clonal hematopoiesis of indeterminate potential (CHIP) is a recently identified process where older patients accumulate distinct subclones defined by recurring somatic mutations in hematopoietic stem cells. CHIP's implications for stem cell transplantation have been harder to identify due to the high degree of mutational heterogeneity that is present within the genetically distinct subclones. In order to gain a better understanding of CHIP and the impact of clonal dynamics on transplantation outcomes, we created a mathematical model of clonal competition dynamics. Our analyses highlight the importance of understanding competition intensity between healthy and mutant clones. Importantly, we highlight the risk that CHIP poses in leading to dominance of precancerous mutant clones and the risk of donor derived leukemia. Furthermore, we estimate the degree of competition intensity and bone marrow niche decline in mice during aging by using our modeling framework. Together, our work highlights the importance of better characterizing the ecological and clonal composition in hematopoietic donor populations at the time of stem cell transplantation.

Genomic landscape and clonal evolution of acute myeloid leukemia with t(8;21): an international study on 331 patients

Acute myeloid leukemia with t(8;21)(q22;q22) is characterized by considerable clinical and biological heterogeneity leading to relapse in up to 40% of patients. We sequenced coding regions or hotspot areas of 66 recurrently mutated genes in a cohort of 331 t(8;21) patients. At least 1 mutation, in addition to t(8;21), was identified in 95%, with a mean of 2.2 driver mutations per patient. Recurrent mutations occurred in genes related to RAS/RTK signaling (63.4%), epigenetic regulators (45%), cohesin complex (13.6%), MYC signaling (10.3%), and the spliceosome (7.9%). Our study identified mutations in previously unappreciated genes: GIGYF2, DHX15, and G2E3 Based on high mutant levels, pairwise precedence, and stability at relapse, epigenetic regulator mutations were likely to occur before signaling mutations. In 34% of RAS/RTKmutated patients, we identified multiple mutations in the same pathway. Deep sequencing (∼42 000×) of 126 mutations in 62 complete remission samples from 56 patients identified 16 persisting mutations in 12 patients, of whom 5 lacked RUNX1-RUNX1T1 in quantitative polymerase chain reaction analysis. KIT high mutations defined by a mutant level ≥25% were associated with inferior relapse-free survival (hazard ratio, 1.96; 95% confidence interval, 1.22-3.15; P = .005). Together with age and white blood cell counts, JAK2, FLT3-internal tandem duplicationhigh, and KIT high mutations were identified as significant prognostic factors for overall survival in multivariate analysis. Whole-exome sequencing was performed on 19 paired diagnosis, remission, and relapse trios. Exome-wide analysis showed an average of 16 mutations with signs of substantial clonal evolution. Based on the resemblance of diagnosis and relapse pairs, genetically stable (n = 13) and unstable (n = 6) subgroups could be identified.

Prevention of cancer dormancy by Fbxw7 ablation eradicates disseminated tumor cells

Dormant cancer cells known as disseminated tumor cells (DTCs) are often present in bone marrow of breast cancer patients. These DTCs are thought to be responsible for the incurable recurrence of breast cancer. The mechanism underlying the long-term maintenance of DTCs remains unclear, however. Here, we show that Fbxw7 is essential for the maintenance of breast cancer dormancy. Genetic ablation of Fbxw7 in breast cancer cells disrupted the quiescence of DTCs, rendering them proliferative, in mouse xenograft and allograft models. Fbxw7-deficient DTCs were significantly depleted by treatment with paclitaxel, suggesting that cell proliferation induced by Fbxw7 ablation sensitized DTCs to chemotherapy. The combination of Fbxw7 ablation and chemotherapy reduced the number of DTCs even when applied after tumor cell dissemination. Mice injected with Fbxw7-deficient cancer cells survived longer after tumor resection and subsequent chemotherapy than did those injected with wild-type cells. Furthermore, database analysis revealed that breast cancer patients whose tumors expressed FBXW7 at a high level had a poorer prognosis than did those with a low FBXW7 expression level. Our results suggest that a wake-up strategy for DTCs based on Fbxw7 inhibition might be of value in combination with conventional chemotherapy for the treatment of breast cancer.

Epigenetic Restoration of Fetal-like IGF1 Signaling Inhibits Leukemia Stem Cell Activity

Acute leukemias are aggressive malignancies of developmentally arrested hematopoietic progenitors. We sought here to explore the possibility that changes in hematopoietic stem/progenitor cells during development might alter the biology of leukemias arising from this tissue compartment. Using a mouse model of acute T cell leukemia, we found that leukemias generated from fetal liver (FL) and adult bone marrow (BM) differed dramatically in their leukemia stem cell activity with FL leukemias showing markedly reduced serial transplantability as compared to BM leukemias. We present evidence that this difference is due to NOTCH1-driven autocrine IGF1 signaling, which is active in FL cells but restrained in BM cells by EZH2-dependent H3K27 trimethylation. Further, we confirmed this mechanism is operative in human disease and show that enforced IGF1 signaling effectively limits leukemia stem cell activity. These findings demonstrate that resurrecting dormant fetal programs in adult cells may represent an alternate therapeutic approach in human cancer.

Impact on acute myeloid leukemia relapse in granulocyte colony-stimulating factor application: a meta-analysis

OBJECTIVES

This meta-analysis evaluated the impact of granulocyte colony-stimulating factor (G-CSF) added to chemotherapy on treatment outcomes including survival and disease recurrence in patients with acute myeloid leukemia (AML).

METHODS

Medline, Cochrane, EMBASE, and Google Scholar databases were searched until 19 September 2016 using search terms. Studies that investigated patients with AML who underwent stem-cell transplantation were included.

RESULTS

The overall analysis revealed a significant improvement in overall survival (OS) (P = .019) and disease-free survival (DFS) (P = .002) for patients receiving G-CSF with chemotherapy. Among patients without prior AML treatment, there was a significant improvement in DFS (P = .014) and reduction in incidence of relapse (P = .015) for those who received G-CSF. However, subgroup analyses found no significant difference between G-CSF (+) and G-CSF (-) treatments in rates of OS (P = .104) and complete remission (CR) (P = .572) for patients without prior AML treatment. Among patients with relapsed/refractory AML, there was no significant difference found between G-CSF (+) and G-CSF (-) groups for OS (P = .225), DFS (P = .209), and CR (P = .208).

DISCUSSION

Treatment with chemotherapy plus G-CSF appears to provide better survival and treatment responses compared with chemotherapy alone, particularly for patients with previously untreated AML.

ABBREVIATIONS

AML, acute myeloid leukemia; CI, confidence interval; CR, complete remission; DFS, disease-free survival; G-CSF, granulocyte colony-stimulating factor; GM-CSF, granulocyte macrophage colony-stimulating factor; HR, hazard ratio; MDS, myelodysplastic syndrome; OR, odds ratio; OS, overall survival; RCTs, randomized control trials; RR, relative risk.

The bone marrow microenvironment in health and disease at a glance

The bone marrow microenvironment (BMM) is the 'domicile' of hematopoietic stem cells, as well as of malignant processes that can develop there. Multiple and complex interactions with the BMM influence hematopoietic stem cell (HSC) physiology, but also the pathophysiology of hematological malignancies. Reciprocally, hematological malignancies alter the BMM, in order to render it more hospitable for malignant progression. In this Cell Science at a Glance article and accompanying poster, we highlight concepts of the normal and malignant hematopoietic stem cell niches. We present the intricacies of the BMM in malignancy and provide approaches for targeting the interactions between malignant cells and their BMM. This is done in an effort to augment existing treatment strategies in the future.

Mathematical modeling of the impact of cytokine response of acute myeloid leukemia cells on patient prognosis

Acute myeloid leukemia (AML) is a heterogeneous disease. One reason for the heterogeneity may originate from inter-individual differences in the responses of leukemic cells to endogenous cytokines. On the basis of mathematical modeling, computer simulations and patient data, we have provided evidence that cytokine-independent leukemic cell proliferation may be linked to early relapses and poor overall survival. Depending whether the model of cytokine-dependent or cytokine-independent leukemic cell proliferation fits to the clinical data, patients can be assigned to two groups that differ significantly with respect to overall survival. The modeling approach further enables us to identify parameter constellations that can explain unexpected responses of some patients to external cytokines such as blast crisis or remission without chemotherapy.

The autophagy scaffold protein ALFY is critical for the granulocytic differentiation of AML cells

Acute myeloid leukemia (AML) is a malignancy of myeloid progenitor cells that are blocked in differentiation. Acute promyelocytic leukemia (APL) is a rare form of AML, which generally presents with a t(15;17) translocation causing expression of the fusion protein PML-RARA. Pharmacological doses of all-trans retinoic acid (ATRA) induce granulocytic differentiation of APL cells leading to cure rates of >80% if combined with conventional chemotherapy. Autophagy is a lysosomal degradation pathway for the removal of cytoplasmic content and recycling of macromolecules. ATRA induces autophagy in ATRA-sensitive AML and APL cells and autophagy inhibition attenuates ATRA-triggered differentiation. In this study, we aimed at identifying if the autophagy-linked FYVE-domain containing protein (ALFY/WDFY3) is involved in autophagic degradation of protein aggregates contributes to ATRA therapy-induced autophagy. We found that ALFY mRNA levels increase significantly during the course of ATRA-induced differentiation of APL and AML cell lines. Importantly ALFY depletion impairs ATRA-triggered granulocytic differentiation of these cells. In agreement with its function in aggrephagy, knockdown of ALFY results in reduced ATRA-induced proteolysis. Our data further suggest that PML-RARα is an autophagy substrate degraded with the help of ALFY. In summary, we present a crucial role for ALFY in retinoid triggered maturation of AML cells.

Relationship between white blood cell count elevation and clinical response after G-CSF priming chemotherapy for acute myeloid leukemia

We retrospectively analyzed the relationship between white blood cell (WBC) count elevation after priming and clinical response in 115 patients with AML (61 untreated and 54 relapsed or refractory) treated with low-dose cytarabine, aclarubicin, and G-CSF priming. Receiver operating characteristic curve analysis showed that the ratio of maximum WBC count to pretreatment WBC count (WBCratio) was most strongly associated with complete remission (CR) in previously untreated patients among several parameters we analyzed in this study; however, the prediction accuracy was not clinically significant considering the area under the curve of 0.694. Based on the cutoff value of the WBCratio, CR rate and event-free survival in the high WBCratio group were significantly better than those in the low WBCratio group in untreated patients. Regarding the WBC differential counts, a high ratio of the maximum to pretreatment value of neutrophils rather than that of peripheral blasts was associated with a superior CR rate. In addition, an increase in blasts after G-CSF priming had a significant negative impact on CR rate in untreated patients. In conclusion, an increase in blast counts after G-CSF priming was not predictive of achieving CR.

Including historical data in the analysis of clinical trials: Is it worth the effort?

Data of previous trials with a similar setting are often available in the analysis of clinical trials. Several Bayesian methods have been proposed for including historical data as prior information in the analysis of the current trial, such as the (modified) power prior, the (robust) meta-analytic-predictive prior, the commensurate prior and methods proposed by Pocock and Murray et al. We compared these methods and illustrated their use in a practical setting, including an assessment of the comparability of the current and the historical data. The motivating data set consists of randomised controlled trials for acute myeloid leukaemia. A simulation study was used to compare the methods in terms of bias, precision, power and type I error rate. Methods that estimate parameters for the between-trial heterogeneity generally offer the best trade-off of power, precision and type I error, with the meta-analytic-predictive prior being the most promising method. The results show that it can be feasible to include historical data in the analysis of clinical trials, if an appropriate method is used to estimate the heterogeneity between trials, and the historical data satisfy criteria for comparability.

Therapeutic value of clofarabine in younger and middle-aged (18-65 years) adults with newly diagnosed AML

Clofarabine has demonstrated antileukemic activity in acute myeloid leukemia (AML) but has yet to be critically evaluated in younger adults in the frontline with standard chemotherapy. We compared 2 induction regimens in newly diagnosed patients ages 18 to 65 with acute myeloid leukemia (AML)/high-risk myelodysplastic syndromes, that is, idarubicine-cytarabine (cycle I) and amsacrine-cytarabine (cycle II) without or with clofarabine (10 mg/m² on days 1-5 of each of both cycles). Consolidation involved chemotherapy with or without hematopoietic stem cell transplantation. Event-free survival (EFS, primary endpoint) and other clinical endpoints and toxicities were assessed. We randomized 402 and 393 evaluable patients to the control or clofarabine induction treatment arms. Complete remission rates (89%) did not differ but were attained faster with clofarabine (66% vs 75% after cycle I). Clofarabine added grades 3 to 4 toxicities and delayed hematological recovery. At a median follow-up of 36 months, the study reveals no differences in overall survival and EFS between the control (EFS, 35% ± 3 [standard error] at 4 years) and clofarabine treatments (38% ± 3) but a markedly reduced relapse rate (44% ± 3 vs 35% ± 3) in favor of clofarabine and an increased death probability in remission (15% ± 2 vs 22% ± 3). In the subgroup analyses, clofarabine improved overall survival and EFS for European Leukemia Net (ELN) 2010 intermediate I prognostic risk AML (EFS, 26% ± 4 vs 40% ± 5 at 4 years; Cox P = .002) and for the intermediate risk genotype NPM1 wild-type/FLT3 without internal-tandem duplications (EFS, 18% ± 5 vs 40% ± 7; Cox P < .001). Clofarabine improves survival in subsets of intermediate-risk AML only. HOVON-102 study is registered at Netherlands Trial Registry #NTR2187.

Update on acute myeloid leukemia stem cells: New discoveries and therapeutic opportunities

The existence of cancer stem cells has been well established in acute myeloid leukemia. Initial proof of the existence of leukemia stem cells (LSCs) was accomplished by functional studies in xenograft models making use of the key features shared with normal hematopoietic stem cells (HSCs) such as the capacity of self-renewal and the ability to initiate and sustain growth of progenitors in vivo. Significant progress has also been made in identifying the phenotype and signaling pathways specific for LSCs. Therapeutically, a multitude of drugs targeting LSCs are in different phases of preclinical and clinical development. This review focuses on recent discoveries which have advanced our understanding of LSC biology and provided rational targets for development of novel therapeutic agents. One of the major challenges is how to target the self-renewal pathways of LSCs without affecting normal HSCs significantly therefore providing an acceptable therapeutic window. Important issues pertinent to the successful design and conduct of clinical trials evaluating drugs targeting LSCs will be discussed as well.

Feasibility of BAALC gene expression for detection of minimal residual disease and risk stratification in normal karyotype acute myeloid leukaemia

High BAALC gene expression has been associated with poor prognosis in cytogenetically normal acute myeloid leukaemia (CN-AML) and has been suggested as a suitable marker for assessing minimal residual disease (MRD). The purpose of this study was to substantiate these findings by the analysis of a large data set of 632 diagnostic and follow-up samples in 142 intensively treated CN-AML patients. Paired diagnostic/relapse samples of 35 patients revealed stable high BAALC expression in 89%, irrespective of a high proportion of clonal evolution found in 49% of these cases. High BAALC expression, both directly after induction chemotherapy and within 3-6 months after induction chemotherapy, correlated significantly with shorter event-free survival and overall survival. Moreover, 8 of 10 patients displaying high BAALC expression levels after completion of induction therapy as well as 5 of 5 patients exhibiting high BAALC expression levels within 3-6 months after induction chemotherapy experienced relapse with a median of 197 and 101 days, respectively, from sampling to relapse. Thus, BAALC expression-based MRD detection during therapy may be considered a strategy to identify patients at high risk of relapse.

Key role for neutrophils in radiation-induced antitumor immune responses: Potentiation with G-CSF

Radiation therapy (RT), a major modality for treating localized tumors, can induce tumor regression outside the radiation field through an abscopal effect that is thought to involve the immune system. Our studies were designed to understand the early immunological effects of RT in the tumor microenvironment using several syngeneic mouse tumor models. We observed that RT induced sterile inflammation with a rapid and transient infiltration of CD11b⁺Gr-1^high+ neutrophils into the tumors. RT-recruited tumor-associated neutrophils (RT-Ns) exhibited an increased production of reactive oxygen species and induced apoptosis of tumor cells. Tumor infiltration of RT-Ns resulted in sterile inflammation and, eventually, the activation of tumor-specific cytotoxic T cells, their recruitment into the tumor site, and tumor regression. Finally, the concurrent administration of granulocyte colony-stimulating factor (G-CSF) enhanced RT-mediated antitumor activity by activating RT-Ns. Our results suggest that the combination of RT and G-CSF should be further evaluated in preclinical and clinical settings.

Which Questionnaire Should Be Used to Measure Quality-of-Life Utilities in Patients with Acute Leukemia? An Evaluation of the Validity and Interpretability of the EQ-5D-5L and Preference-Based Questionnaires Derived from the EORTC QLQ-C30

OBJECTIVES

The aim of this study was to assess the validity and interpretability of different preference-based questionnaires (generic 5-level EuroQol five-dimensional questionnaire [EQ-5D-5L], cancer-specific Quality of Life Questionnaire Preference-Based Measure, and European Organization of Randomized Controlled Trials 8 Dimension [EORTC-8D]) in patients with acute leukemia.

METHODS

Patients who participated in Hemato-Oncologie voor Volwassenen Nederland (HOVON - the Haemato Oncology Foundation for Adults in the Netherlands) clinical trials between 1999 and 2011 at a single hospital were invited to complete the questionnaires. Interpretability was evaluated by the frequency of incomplete data and highest and lowest possible scores. Content validity was evaluated by exploring the health-related quality-of-life domains included in the questionnaires. Construct validity was assessed using correlations with other quality-of-life scales (EQ-visual analogue scale score and global quality-of-life scale of the EORTC Quality of Life Questionnaire) and ability to distinguish between patients with different health statuses.

RESULTS

Questionnaires were returned by 89% (111 of 125) of the patients. Six to seven respondents did not return full questionnaires. Perfect health on the EQ-5D-5L was reported by 32 respondents and many of them (N = 17) did report health problems on other questionnaires. All questionnaires were strongly correlated (range 0.61-0.78) with other quality-of-life scales and yielded substantially different utility values for patients with different health statuses. Nevertheless, the disease-specific preference-based questionnaires showed greater discriminatory power.

CONCLUSIONS

Although the Quality of Life Questionnaire Preference-Based Measure and the EORTC-8D appear to have better validity, this study does not provide any strong evidence against the use of the EQ-5D-5L for measuring quality-of-life utilities in acute leukemia. However, our findings need to be confirmed in larger longitudinal studies.

Decitabine in the Treatment of Acute Myeloid Leukemia and Myelodysplastic Syndromes, Which Combined with Complex Karyotype Respectively

BACKGROUND

We conducted a study exploring the clinical safety and efficacy of decitabine in patients with acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS), combined with a complex karyotype.

MATERIALS AND METHODS

From April 2009 to September 2013, a total of 35 patients with AML/MDS combined with a complex karyotype diagnosed in the First Affiliated Hospital of Soochow University were included for retrospective analysis. All patients were treated with decitabine alone (20 mg/m2 daily for 5 days) or combination AAG chemotherapy (Acla 20 mg qod*4d, Ara-C 10 mg/m2 q12h*7d, G-CSF 300 μg qd, the dose of G-CSF adjusted to the amount in blood routinely).

RESULTS

In 35 patients, 15 exhibited a complete response (CR), and 6 a partial response (PR), the overall response rate (CR+PR) being 60% (21 of 35). Median disease-free survival was 18 months and overall survival was 14 months. In the 15 MDS patients with a complex karyotype, the CR rate was 53.3% (8 of 15); in 20 AML patients with complex karyotype, the overall response rate was 65% (13 of 20). The response rate of decitabine alone (22 cases) was 56.5% (13 of 22), while in the combination chemotherapy group (13 cases), the effective rate was 61.5% (8 of 13)(P>0.05). There are 15 patients with chromosome 7 aberration, after treatment with decitabine, 7 CR, 3 PR, overall response rate was 66.7% (10 of 15). Of 18 patients with 3 to 5 kinds of chromosomal abnormalities, 66.7% demonstrated a response; of 17 with more than 5 chromosomal abnormalities, 52.9% had a response. In the total of 35 patients, with one course (23 patients) and ≥two courses (12 patients), the overall response rate was 40.9% and 92.3% (P<0.05). Grade III to IV hematological toxicity was observed in 27 cases (75%). Grade III to IV infections were clinically documented in 7 (20%). Grades I to II non-hematological toxicity were infections (18 patients), haematuria (2 patients), and bleeding (3 patients). With follow-up until September 2013, 7 patients were surviving, 18 had died and 10 were lost to follow-up. In the 6 cases who underwent allogeneic hematopoietic stem cell transplantation (HSCT) all were still relapse-free survivors.

CONCLUSIONS

Decitabine alone or combination with AAG can improve outcome of AML/MDS with a complex karyotype, there being no significant difference decitabine in inducing remission rates in patients with different karyotype. Increasing the number of courses can improve efficiency. This approach with fewer treatment side effects in patients with a better tolerance should be employed in order to create an improved subsequent chance for HSCT.

Disseminated intravascular coagulation at diagnosis is a strong predictor for thrombosis in acute myeloid leukemia

Venous thromboembolism is a common complication in patients with cancer, but only limited data are available in acute myeloid leukemia (AML). In a prospective study in a cohort of 272 adult patients (aged 18-65) and an independent validation cohort of 132 elderly adults (aged >60) with newly diagnosed AML, we assessed markers of disseminated intravascular coagulation (DIC) (fibrinogen, D-dimer, α-2-antiplasmin, antitrombin, prothrombin time, and platelet count) and the DIC score according the International Society of Thrombosis and Haemostasis and their associations with the occurrence of venous and arterial thrombosis during follow-up. The prevalence of thrombosis was 8.7% (4.7% venous, 4.0% arterial) in the younger adults over a median follow-up of 478 days and 10.4% (4.4% venous, 5.9% arterial) in elderly patients. Most thrombotic events (66%) occurred before the start of the second course of chemotherapy. The calculated DIC score significantly predicted venous and arterial thrombosis with a hazard ratio (HR) for a high DIC score (≥5) of 4.79 (1.71-13.45). These results were confirmed in the validation cohort of elderly patients with AML (HR 11.08 [3.23-38.06]). Among all DIC parameters, D-dimer levels are most predictive for thrombosis with an HR of 12.3 (3.39-42.64) in the first cohort and an HR of 7.82 (1.95-31.38) in validation cohort for a D-dimer >4 mg/L vs ≤4 mg/L. It is concluded that venous and arterial thrombosis may develop in ∼10% of AML patients treated with intensive chemotherapy, which to a large extent can be predicted by the presence of DIC at time of AML diagnosis.

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.

Dose-enhanced combined priming regimens for refractory acute myeloid leukemia and middle-and-high-risk myelodysplastic syndrome: a single-center, retrospective cohort study

Objective

To assess chemotherapeutic regimens for refractory acute myeloid leukemia (AML) and middle-and-high-risk myelodysplastic syndrome (MDS).

Methods

Between 2004 and 2014, 44 patients with refractory AML and 36 patients with MDS were treated with new priming regimens (CHAG, CHTG, CHMG, or CTMG), and 77 patients with refractory AML and 52 patients with MDS were treated with conventional priming regimens (CHG or CAG). This was a single-center retrospective analysis of remission, adverse event, mortality, and survival. The capacity of clinical features (including the expression of co-stimulatory molecule B7.1 on tumor cells) to influence survival was assessed by multivariate Cox regression.

Results

Complete and partial remission rates (RRs) were significantly higher in AML patients treated with new regimens compared to conventional ones (68.2% vs 13.6%, P<0.05). Complete and partial remission were also significantly higher in patients with MDS treated with new regimens (55.6% vs 19.4%, P<0.05). However, although survival advantages were observed in the first year, the new regimens did not significantly improve 3-year overall survival (P>0.05). Patients administered the new regimens experienced more severe and sustained myelosuppression (P<0.05), but no severe adverse events or treatment-related deaths were observed. The rate of non-hematological side effects did not differ significantly between treatment regimens (P>0.05). Both RR and B7.1 expression were significantly higher in patients with AML-M2 and M5 (P<0.05).

Conclusion

The new priming regimens improved the RR, lowered the recurrence rate, and improved survival in AML and middle-and-high-risk MDS, without significantly increasing adverse events.

To wake up cancer stem cells, or to let them sleep, that is the question

Cancer stem cells (CSCs) generate transient-amplifying cells and thereby contribute to cancer propagation. A fuller understanding of the biological features of CSCs is expected to lead to the development of new anticancer therapies capable of eradicating this life-threatening disease. Cancer stem cells are known to maintain a non-proliferative state and to enter the cell cycle only infrequently. Given that conventional anticancer therapies preferentially target dividing cells, CSCs are resistant to such treatments, with those remaining after elimination of bulk cancer cells potentially giving rise to disease relapse and metastasis as they re-enter the cell cycle after a period of latency. Targeting of the switch between quiescence and proliferation in CSCs is therefore a potential strategy for preventing the reinitiation of malignancy, underscoring the importance of elucidation of the mechanisms by which these cells are maintained in the quiescent state. The fundamental properties of CSCs are thought to be governed cooperatively by internal molecules and cues from the external microenvironment (stem cell niche). Several such intrinsic and extrinsic regulators are responsible for the control of cell cycle progression in CSCs. In this review, we address two opposite approaches to the therapeutic targeting of CSCs - wake-up and hibernation therapies - that either promote or prevent the entry of CSCs into the cell cycle, respectively, and we discuss the potential advantages and risks of each strategy.