Prognostic factors in acute myeloid leukaemia

Accurate identification of locally aneuploid cells by incorporating cytogenetic information in single cell data analysis

Single-cell RNA sequencing is a powerful tool to investigate the cellular makeup of tumor samples. However, due to the sparse data and the complex tumor microenvironment, it can be challenging to identify neoplastic cells that play important roles in tumor growth and disease progression. This is especially relevant for blood cancers, where neoplastic cells may be highly similar to normal cells. To address this challenge, we have developed partCNV and partCNVH, two methods for rapid and accurate detection of aneuploid cells with local copy number deletion or amplification. PartCNV uses an expectation-maximization (EM) algorithm with mixtures of Poisson distributions and incorporates cytogenetic information to guide the classification. PartCNVH further improves partCNV by integrating a hidden Markov model for feature selection. We have thoroughly evaluated the performance of partCNV and partCNVH through simulation studies and real data analysis using three scRNA-seq datasets from blood cancer patients. Our results show that partCNV and partCNVH have favorable accuracy and provide more interpretable results compared to existing methods. In the real data analysis, we have identified multiple biological processes involved in the oncogenesis of myelodysplastic syndromes and acute myeloid leukemia.

Biomarker‑driven phase Ib clinical trial of OPB‑111077 in acute myeloid leukemia

OPB-111077 is a novel, highly specific oral signal transducer and activator of transcription 3 inhibitor that has exhibited good efficacy against solid and blood cancers, including acute myeloid leukemia (AML), in preclinical models. In the present study, a phase 1b, two-stage, 3+3 dose-escalation clinical trial [dose level (DL)1 of 200 mg/day and DL2 of 250 mg/day on a once daily dose schedule in 28-day cycles] was conducted to assess the maximum tolerated dose (MTD), safety profile and the preliminary antitumor activity of OPB-111077 in patients with high-risk AML. A preliminary preclinical analysis evaluated the anti-proliferative activity of OPB-111077 in 19 patients with AML with a Vivia Biotech ex vivo PharmaFlow precision medicine test. A total of 12 patients were ultimately enrolled in the trial: 5 patients (42%) were treated with DL1, and 7 (58%) were escalated to DL2 of OPB-111077. Dose-limiting toxicities were not observed and the MTD was not reached. In addition, the most frequently reported treatment-emergent adverse events were nausea, vomiting and fatigue. Finally, clinical activity (overall response) was observed in 3 patients (25%). On the whole, the present study demonstrates that OPB-111077 exhibits a good safety and tolerability profile and an acceptable clinical response in patients with high-risk AML. A biomarker-driven design is useful for selecting the study population upfront.

Prognostic significance of CXCR4 expression in acute myeloid leukemia

Background

CXCR4 chemokine receptors play an important role in leukemia proliferation, extramedullary migration, infiltration, adhesion, and resistance to chemotherapy drugs.

Methods

The CXCR4 expression by flow cytometry in 122 acute myeloid leukemia (AML) patients between 2010 and 2014 was analyzed.

Results

The expression of CXCR4 in AML‐M4/M5 was found to be significantly higher than that of other subtypes according to both FAB subtype and WHO classification. The FLT3‐ITD mutant was significantly higher in high CXCR4 expression group (P = .0086). Our data also showed that CXCR4 expression was correlated with CD64 expression. Low CXCR4 expression on AML cells was associated with better prognosis, and the median overall survival (OS) for low CXCR4 expression patients was 318 days, compared with 206 days for patients with high CXCR4 expression (P = .045). Multivariate analysis revealed that CXCR4 expression, age, and extramedullary infiltration were independent prognostic factors.

Conclusions

Our study demonstrated that CXCR4 expression in AML was an independent prognostic predictor for disease survival that could be rapidly and easily determined by flow cytometry at disease presentation.

A novel scoring system for acute myeloid leukemia risk assessment based on the expression levels of six genes

Acute myeloid leukemia (AML) is the most common type of acute leukemia and is a heterogeneous clonal disorder. At present, the pathogenesis of AML and potential methods to effectively prevent AML have become areas of interest in research. In the present study, two messenger ribonucleic acid sequencing datasets of patients with AML were downloaded from the Cancer Genome Atlas and Gene Expression Omnibus databases. The differentially expressed genes (DEGs) of the poor and good prognosis groups were screened using the Linear Models for Microarray Data package, and the prognosis-related genes were screened using univariate Cox regression analysis. A total of 206 significant DEGs were identified. Following univariate and multivariate Cox regression analysis, 14 genes significantly associated with prognosis were screened and six of these genes, including triggering receptor expressed on myeloid cells 2 (TREML2), cysteine-glutamate transporter (SLC7A11), NACHT, LRR, and PYD domains-containing protein 2 (NLRP2), DNA damage-inducible transcript 4 protein (DDIT4), lymphocyte‑specific protein 1 (LSP1) and C-type lectin domain family 11 member A (CLEC11A), were used to construct model equations for risk assessment. The prognostic scoring system was used to evaluate risk for each patient, and the results showed that patients in the low-risk group had a longer survival time, compared with those in the high-risk group (P=9.59e-06 for the training dataset and P=0.00543 for the validation dataset). A total of eight main Kyoto Encyclopedia of Genes and Genomes pathways were identified, the top three of which were hematopoietic cell lineage, focal adhesion, and regulation of actin cytoskeleton. Taken together, the results showed that the scoring system established in the present study was credible and that the six genes were identified, which were significantly associated with the risk assessment of AML, offer potential as prognostic biomarkers. These findings may provide clues for further clarifying the pathogenesis of AML.

Upregulated TCRζ improves cytokine secretion in T cells from patients with AML

Previous studies indicated that upregulating TCRζ partially recovers T cell function in patients with leukemia. In this study, we characterized the cytokine profile of TCRζ-transfected T cells from acute myeloid leukemia (AML) patients by Quantibody®Array Glass Chip. Firstly, the significantly lower expression of TCRζ in CD3⁺/TCRζ⁺ cells from AML patients was found. Increased secretion of IL-2, IL-8, IL-10, IL-13, IFN-γ, TNF-α, GM-CSF, growth-regulated oncogene (GRO), MIP-1b, and regulated on activation, normal T cell expressed and secreted (RANTES) could be detected in T cells from AML patients after TCRζ upregulating. We concluded that upregulating TCRζ in T cells from AML can alter the secretion profile of cytokines and chemokine which are involved in T cell proliferation and activation.

Phosphoinositide-dependent kinase 1 regulates leukemia stem cell maintenance in MLL-AF9-induced murine acute myeloid leukemia

Although great efforts have been made to improve available therapies, the mortality rate of acute myeloid leukemia (AML) remains high due to poor treatment response and frequent relapse after chemotherapy. Leukemia stem cells (LSCs) are thought to account for this poor prognosis and relapse. Phosphoinositide-dependent kinase 1 (PDK1) is a critical regulator of the PI3K/Akt pathway and has been shown to be frequently activated in leukemia. However, the role of PDK1 in the regulation of LSCs in AML is still not clear. Using a PDK1 conditional deletion MLL-AF9 murine AML model, we revealed that the deletion of PDK1 prolonged the survival of AML mice by inducing LSC apoptosis. This was accompanied by the increased expression of the pro-apoptotic genes Bax and p53 and the reduced expression of Stat5, which has been shown to be constitutively activated in leukemia. Thus, our findings suggest that PDK1 plays an essential role in maintaining LSCs. Further delineating the function of PDK1 in LSCs may provide a new strategy for the improved treatment of AML relapse.

Hierarchy in gene expression is predictive of risk, progression, and outcome in adult acute myeloid leukemia

Cancer progresses with a change in the structure of the gene network in normal cells. We define a measure of organizational hierarchy in gene networks of affected cells in adult acute myeloid leukemia (AML) patients. With a retrospective cohort analysis based on the gene expression profiles of 116 AML patients, we find that the likelihood of future cancer relapse and the level of clinical risk are directly correlated with the level of organization in the cancer related gene network. We also explore the variation of the level of organization in the gene network with cancer progression. We find that this variation is non-monotonic, which implies the fitness landscape in the evolution of AML cancer cells is non-trivial. We further find that the hierarchy in gene expression at the time of diagnosis may be a useful biomarker in AML prognosis.

Azacitidine in 302 patients with WHO-defined acute myeloid leukemia: results from the Austrian Azacitidine Registry of the AGMT-Study Group

Data on efficacy and safety of azacitidine in acute myeloid leukemia (AML) with >30 % bone marrow (BM) blasts are limited, and the drug can only be used off-label in these patients. We previously reported on the efficacy and safety of azacitidine in 155 AML patients treated within the Austrian Azacitidine Registry (clinicaltrials.gov identifier NCT01595295). We herein update this report with a population almost twice as large (n = 302). This cohort included 172 patients with >30 % BM blasts; 93 % would have been excluded from the pivotal AZA-001 trial (which led to European Medicines Agency (EMA) approval of azacitidine for high-risk myelodysplastic syndromes (MDS) and AML with 20-30 % BM blasts). Despite this much more unfavorable profile, results are encouraging: overall response rate was 48 % in the total cohort and 72 % in patients evaluable according to MDS-IWG-2006 response criteria, respectively. Median OS was 9.6 (95 % CI 8.53-10.7) months. A clinically relevant OS benefit was observed with any form of disease stabilization (marrow stable disease (8.1 months), hematologic improvement (HI) (9.7 months), or the combination thereof (18.9 months)), as compared to patients without response and/or without disease stabilization (3.2 months). Age, white blood cell count, and BM blast count at start of therapy did not influence OS. The baseline factors LDH >225 U/l, ECOG ≥2, comorbidities ≥3, monosomal karyotype, and prior disease-modifying drugs, as well as the response-related factors hematologic improvement and further deepening of response after first response, were significant independent predictors of OS in multivariate analysis. Azacitidine seems effective in WHO-AML, including patients with >30 % BM blasts (currently off-label use). Although currently not regarded as standard form of response assessment in AML, disease stabilization and/or HI should be considered sufficient response to continue treatment with azacitidine.

The role of hypomethylating agents in the treatment of elderly patients with AML

There is a major unmet medical need for treatment options in elderly patients with acute myeloid leukemia (AML) who are deemed ineligible for intensive treatment. The recent approval of decitabine in the European Union for the treatment of patients with AML≥ 65 years old highlights the potential for hypomethylating agents in this setting. Here, we review evidence to support the use of hypomethylating agents in elderly patients and emphasize the importance of tolerability and quality of life considerations. We focus on the rationale for the continued clinical development of the ribonucleoside analog azacitidine in this setting. We discuss potential differences in the activity of azacitidine and decitabine in different patient subgroups that could possibly be explained by important differences in mechanism of action. Finally, we assess practical challenges that will be faced when integrating hypomethylating agents into clinical practice, such as how to define ineligibility for intensive treatment.

A study for evaluation of different diagnostic approaches in acute leukemia in Egypt

Cytomorphology, cytochemistry, immunophenotyping, in addition to cytogenetic and molecular analyses have specific roles in the diagnosis and management of acute leukemias. This work was designed as a comparative study of different available methods for diagnosis of acute leukemia. The study comprised 47 cases with acute leukemia (21 cases with ALL and 26 cases with AML). Peripheral blood and bone marrow samples were subjected to through morphological examination of Leishman-stained smears, cytochemical analysis, immunophenotyping, conventional cytogenetic banding analysis, fluorescence in situ hybridization (FISH) for selected cases, and RT-PCR for detection of BCR-ABL rearrangement. The results of the study revealed that careful examination of Romanowsky-stained peripheral blood and BM films is fundamental in the diagnosis of acute leukemias, and when considered together with clinical and hematological features, indicates which of the more specialized techniques are most likely to be useful. The major role of cytochemistry was in the diagnosis of AML, while the major role of immunophenotyping was in the diagnosis of acute leukemia, which is not obviously myeloid. Apart from identification of chromosomal abnormalities unique to specific subtypes of leukemia, cytogenetic analysis had a salient impact on anticipating the prognosis and treatment outcome in acute leukemias. We could conclude that the techniques used in this study are considered complementary rather than alternatives and that stepwise employment of strategies is more cost effective than doing all the tests simultaneously.

Azacitidine in patients with WHO-defined AML - results of 155 patients from the Austrian Azacitidine Registry of the AGMT-Study Group

Objective

The Austrian Azacitidine Registry is a multi-center database (ClinicalTrials.gov: NCT01595295). The nature and intent of the registry was to gain a comprehensive view of the use, safety and efficacy of the drug in a broad range of AML-patients treated in real-life scenarios.

Patients and methods

The sole inclusion criteria were the diagnosis of WHO-AML and treatment with at least one dose of azacitidine. No formal exclusion criteria existed. A total of 155 AML-patients who were mostly unfit/ineligible for intensive chemotherapy, or had progressed despite conventional treatment, were included. True ITT-analyses and exploratory analyses regarding the potential prognostic value of baseline-variables/performance-/comorbidity-/risk-scores on overall survival (OS), were performed.

Results

In this cohort of 155 pretreated (60%), and/or comorbid (87%), elderly (45% ≥75 years) AML-patients, azacitidine was well tolerated and efficacious, with an overall response rate (CR, mCR, PR, HI) of 45% in the total cohort (ITT) and 65% in patients evaluable according to IWG-criteria, respectively. Pre-treatment with conventional chemotherapy (P = .113), age ≤/>80 years (P = .853), number of comorbidities (P = .476), and bone marrow (BM) blast count (P = .663) did not influence OS. In multivariate analysis hematologic improvement alone (without the requirement of concomitant bone marrow blast reduction), although currently not regarded as a standard form of response assessment in AML, was sufficient to confer OS benefit (18.9 vs. 6.0 months; P = .0015). Further deepening of response after first response was associated with improved OS (24.7 vs. 13.7 months; P < .001).

Conclusions

In this large cohort of AML-patients treated with azacitidine, age >80 years, number of comorbidities and/or BM-blasts >30% did not adversely impact OS.

Favorable effect of priming with granulocyte colony-stimulating factor in remission induction of acute myeloid leukemia restricted to dose escalation of cytarabine

The clinical value of chemotherapy sensitization of acute myeloid leukemia (AML) with G-CSF priming has remained controversial. Cytarabine is a key constituent of remission induction chemotherapy. The effect of G-CSF priming has not been investigated in relationship with variable dose levels of cytarabine. We randomized 917 AML patients to receive G-CSF (456 patients) or no G-CSF (461 patients) at the days of chemotherapy. In the initial part of the study, 406 patients were also randomized between 2 cytarabine regimens comparing conventional-dose (199 patients) versus escalated-dose (207 patients) cytarabine in cycles 1 and 2. We found that patients after induction chemotherapy plus G-CSF had similar overall survival (43% vs 40%, P = .88), event-free survival (37% vs 31%, P = .29), and relapse rates (34% vs 36%, P = .77) at 5 years as those not receiving G-CSF. However, patients treated with the escalated-dose cytarabine regimen benefited from G-CSF priming, with improved event-free survival (P = .01) and overall survival (P = .003), compared with patients without G-CSF undergoing escalated-dose cytarabine treatment. A significant survival advantage of sensitizing AML for chemotherapy with G-CSF was not apparent in the entire study group, but it was seen in patients treated with escalated-dose cytarabine during remission induction. The HOVON-42 study is registered under The Netherlands Trial Registry (www.trialregister.nl) as #NTR230.

Flow cytometry-based assessment of mitoxantrone efflux from leukemic blasts varies with response to induction chemotherapy in acute myeloid leukemia

BACKGROUND

Accurate prediction of chemotherapy drug resistance would aid treatment decisions in acute myeloid leukemia (AML). The aim of this study was to determine if mitoxantrone efflux from AML blasts would correlate with response to induction chemotherapy.

METHODS

Flow cytometry was used to measure the median fluorescence intensity (MFI) for AML blasts incubated with mitoxantrone [an ATP-binding cassette (ABC) transporter substrate] with or without coincubation with cyclosporine A (a broad-spectrum inhibitor of ABC transporters) and a ratio (MFIR) between the inhibited and uninhibited MFI was calculated.

RESULTS

Among 174 AML patient blast samples, the mean MFIR for complete remission (CR) patients was lower than that obtained for induction failure (IF) patients (mean MFIR ± SD 1.62 ± 0.53 for CR after one cycle of chemotherapy vs. 2.22 ± 1.29 for CR after two cycles and 2.59 ± 0.98 for IF, P < 0.001). Logistic regression analysis determined 2.45 as the MFIR threshold above which 29% of patients achieved CR vs. a CR rate of 84% when the MFIR was ≤ 2.45 (P < 0.0001). In AML patients with normal karyotype (n = 80), CR was obtained for 33% of patients with an MFIR > 2.45 vs. 89% of those with MFIR ≤ 2.45 (P < 0.0001). In patients > age 60 (n = 77), 30% vs. 87% of those with MFIR > vs. ≤ 2.45 achieved CR (P < 0.0001).

CONCLUSIONS

This assay of ABC transporter function can potentially predict response to induction chemotherapy in AML.

Azacitidine in patients with acute myeloid leukemia medically unfit for or resistant to chemotherapy: a multicenter phase I/II study

The safety and efficacy of azacitidine (5-day schedule) were assessed in a multicenter study in 40 patients (median age 72 years) with acute myeloid leukemia (AML) medically unfit for (n = 20) or resistant to chemotherapy (n = 20) from April to October 2008. Median marrow blasts were 42%. After a median follow-up of 13 months, response (complete remission [CR]/partial remission [PR]/hematologic improvement [HI]) was 50% and 10% in newly diagnosed and relapsed/refractory patients, respectively (p = 0.008). Median time-to-response was 2.5 months with a median duration of 5.9 months. Median survival was not reached for responders versus 3.8 months for 15 (38%) patients with stable disease (p < 0.045). High-risk cytogenetics was associated with inferior survival (p = 0.05). Lower marrow blasts on day 15 of cycle 1, irrespective of pretreatment count, predicted subsequent response (p = 0.01). Azacitidine is active and well tolerated in elderly patients with newly diagnosed AML.

Deficient CEBPA DNA binding function in normal karyotype AML patients is associated with favorable prognosis

CCAAT/enhancer binding protein-α (CEBPA) mutations in acute myeloid leukemia (AML) patients with a normal karyotype (NK) confer favorable prognosis, whereas NK-AML patients per se are of intermediate risk. This suggests that blocked CEBPA function characterizes NK-AML with favorable outcome. We determined the prognostic significance of CEBPA DNA binding function by enzyme-linked immunosorbent assay in 105 NK-AML patients. Suppressed CEBPA DNA binding was defined by 21 good-risk AML patients with inv(16) or t(8;21) (both abnormalities targeting CEBPA) and 8 NK-AML patients with dominant-negative CEBPA mutations. NK-AML patients with suppressed CEBPA function showed a better overall survival (P = .0231) and disease-free survival (P = .0069) than patients with conserved CEBPA function. Suppressed CEBPA DNA binding was an independent marker for better overall survival and disease-free survival in a multivariable analysis that included FLT3-ITD, NPM1 and CEBPA mutation status, white blood cell count, age and lactate dehydrogenase. These data indicate that suppressed CEBPA function is associated with favorable prognosis in NK-AML patients.

Acute erythroleukemia: diagnosis and management

Acute erythroleukemia is a rare subtype of acute myeloid leukemia that has undergone several changes in classification over the past 30 years. There are two subtypes of acute erythroleukemia: the more common erythroid/myeloid subtype, defined by the presence of increased erythroid cells and myeloid blasts; and the rarer, pure erythroid subtype, characterized by expansion of immature erythroid cells only. The erythroid/myeloid subtype of acute erythroleukemia is closely related to acute myeloid leukemia with myelodysplasia-related changes, and is frequently characterized by morphological dysplasia and complex karyotype. Pure erythroleukemia is a very uncommon subtype of leukemia associated with a very poor response and survival to current available therapeutic agents. Treatment results for this disease are suboptimal and new drugs are needed. This article summarizes current knowledge in the field of acute erythroleukemia.

Prognostic value of FLT3 mutations among different cytogenetic subgroups in acute myeloid leukemia

BACKGROUND

The impact of FMS-like tyrosine kinase 3 (FLT3) mutations and mutation burden among cytogenetic subgroups of patients with acute myeloid leukemia (AML) other than normal karyotype (NK) AML is unclear.

METHODS

Patients with newly diagnosed AML were divided among 3 cytogenetic subgroups: core binding factor (CBF) AML, NK-AML, and poor-risk AML.

RESULTS

In total, 481 patients were included: 13% had, CBF-AML, 57% had NK-AML, and 30% had poor risk AML, and the frequency of any FLT3 mutations was 20%, 32%, and 7.6% in the respective cytogenetic subgroups. FLT3 mutation did not have an impact on event-free survival (EFS) in patients with CBF-AML (P = .84) and poor-risk AML (P = .37). In patients with NK-AML, EFS was worse in the FLT3-internal tandem duplication (ITD) group (20 weeks vs 41 weeks; P < .00,001) but not in the FLT3-tyrosine kinase domain (TKD) point mutation group (61 weeks vs 41 weeks; P = .15). Worse EFS and overall survival (OS) were observed among patients with NK-AML and higher FLT3-ITD burden but not among patients with FLT3-TKD mutation. In multivariate analysis, FLT3-ITD mutation was prognostic of EFS in patients with NK-AML (hazard ratio, 3.1; P = .03).

CONCLUSIONS

FLT3 mutations did not have a prognostic impact in patients with AML who had good-risk and poor-risk karyotypes. In patients with NK-AML, FLT3-ITD mutations led to worse survival, which was even worse among patients who had high mutation burden.

Genes predictive of outcome and novel molecular classification schemes in adult acute myeloid leukemia

The pretreatment karyotype of leukemic blasts is currently the key determinant in therapy decision making in acute myeloid leukemia (AML). The World Health Organization (WHO) has recognized this important information by including, besides clinical, cytological, cytochemical, and immunophenotypical features, recurrent cytogenetic abnormalities in its classification (Table 1). However, although the WHO defines important biologically and clinically relevant entities, the prognostic value of some of the well-defined cytogenetic subgroups is partially masked in the WHO classification. Moreover, in the recent past a number of novel molecular aberrations with marked prognostic value, which are not yet incorporated in the WHO classifications have been identified. These molecular abnormalities include mutations (e.g., in FLT3, c-KIT, and NPM1), partial duplications (e.g., of MLL and FLT3), and abnormal expression of pathogenetic genes (e.g., EVI1, WT1, BCL2, MDR1, BAALC, and ERG). In addition, novel molecular approaches in genomics, like monitoring the expression levels of thousands of genes in parallel using DNA microarray technology, open possibilities for further refinement of prognostication of AML. Gene expression profiling in AML is already well established and has proven to be valuable to recognize various cytogenetic subtypes, discover novel AML subclasses, and predict clinical outcome. The current advances made in molecular understanding of AML will ultimately lead to a further refinement of prognostics of AML.

Adult acute erythroleukemia: an analysis of 91 patients treated at a single institution

Acute erythroleukemia (AML-M6) is an uncommon subtype of acute myeloid leukemia (AML); it is considered to have a poor prognosis. From 1 January 1980 to 21 May 2008, 91 patients with newly diagnosed AML-M6 were seen at the University of Texas-M.D. Anderson Cancer Center (UT-MDACC). Forty-five patients (50%) had a history of myelodysplatic syndrome (MDS), compared with 41% in our control group (patients with other AML subtypes) (P=0.08). Poor-risk cytogenetics were more common in patients with AML-M6 (61% versus 38%, P=0.001). Complete remission rates were 62% for patients with AML-M6, comparing with 58% for the control group (P=0.35). Median disease free survival (DFS) for patients with AML-M6 was 32 weeks, versus 49 weeks for the control group (P=0.05). Median overall survival (OS) of patients with AML-M6 was 36 weeks, compared with 43 weeks for the control group (P=0.60). On multivariate analysis for DFS and OS, AML-M6 was not an independent risk factor. AML-M6 is commonly associated with a previous diagnosis of MDS and poor-risk karyotype. The diagnosis of AML-M6 does not impart by itself a worse prognosis, and treatment decisions on this disease should be guided by well known AML prognostic factors.

Monosomal karyotype in acute myeloid leukemia: a better indicator of poor prognosis than a complex karyotype

PURPOSE

To investigate the prognostic value of various cytogenetic components of a complex karyotype in acute myeloid leukemia (AML).

PATIENTS AND METHODS

Cytogenetics and overall survival (OS) were analyzed in 1,975 AML patients age 15 to 60 years.

RESULTS

Besides AML with normal cytogenetics (CN) and core binding factor (CBF) abnormalities, we distinguished 733 patients with cytogenetic abnormalities. Among the latter subgroup, loss of a single chromosome (n = 109) conferred negative prognostic impact (4-year OS, 12%; poor outcome). Loss of chromosome 7 was most common, but outcome of AML patients with single monosomy -7 (n = 63; 4-year OS, 13%) and other single autosomal monosomies (n = 46; 4-year OS, 12%) did not differ. Structural chromosomal abnormalities influenced prognosis only in association with a single autosomal monosomy (4-year OS, 4% for very poor v 24% for poor). We derived a monosomal karyotype (MK) as a predictor for very poor prognosis of AML that refers to two or more distinct autosomal chromosome monosomies (n = 116; 4-year OS, 3%) or one single autosomal monosomy in the presence of structural abnormalities (n = 68; 4-year OS, 4%). In direct comparisons, MK provides significantly better prognostic prediction than the traditionally defined complex karyotype, which considers any three or more or five or more clonal cytogenetic abnormalities, and also than various individual specific cytogenetic abnormalities (eg, del[5q], inv[3]/t[3;3]) associated with very poor outcome.

CONCLUSION

MK enables (in addition to CN and CBF) the prognostic classification of two new aggregates of cytogenetically abnormal AML, the unfavorable risk MK-negative category (4-year OS, 26% +/- 2%) and the highly unfavorable risk MK-positive category (4-year OS, 4% +/- 1%).

Improved outcome in childhood acute myeloid leukemia in Singapore with the MRC AML 10 protocol

BACKGROUND

The introduction of the United Kingdom Medical Research Council's 10th AML trial (MRC AML 10) protocol incorporating high-dose anthracycline therapy has improved outcome of children with acute myeloid leukemia (AML). In this study, we review the results of childhood AML therapy in a Singapore university hospital over the last 17 years emphasizing toxicity and outcome.

PROCEDURE

Retrospective analysis revealed 34 children with AML between 1988 and 2003. Prior to September 1996, therapy consisted of: POG-8498 (n = 10), others (n = 9). From September 1996, all but one of 15 children received MRC AML 10 treatment.

RESULTS

At the time of analysis, 17 had died from disease, and 17 patients were alive among whom 2 had relapsed. MRC AML 10-treated patients (n = 14) had significantly better 3-year overall, event-free, and disease-free survival (74% vs. 35%, 77% vs. 20%, 83% vs. 31%; P = 0.019, P = 0.002, and P = 0.010, respectively) and were likelier to achieve complete remission (CR) than non-MRC AML 10 patients (P = 0.102). Among patients who achieved CR, MRC AML 10-treated patients were significantly more likely to achieve CR after only one cycle of chemotherapy (P = 0.016). Hematologic toxicity was similar among the different regimens (P = 0.9).

CONCLUSIONS

These findings suggest that MRC AML 10 treatment results in significantly superior survival, without excess toxicity. Future studies should attempt to elucidate the relative importance of individual MRC AML 10 components and reduce the high cumulative anthracycline dose without compromising outcome.

An antecedent diagnosis of refractory anemia with excess blasts has no influence on mobilization of peripheral blood stem cells and hematopoietic recovery after autologous stem cell transplantation in acute myeloid leukemia

Several studies have reported data on factors influencing mobilization of peripheral blood stem cells (PBSC) in non-myeloid malignancies. On the contrary, data from patients with acute myeloid leukemia (AML) are very limited, in particular, as the impact of an antecedent diagnosis of refractory anemia with excess blasts (RAEB) on mobilization of PBSCs as well as hematopoietic recovery after autologous stem cell transplantation (ASCT) is concerned. We retrospectively analyzed a cohort of 150 consecutive AML patients in first complete remission in order to make a comparison between patients with de novo AML and secondary AML (s-AML) in terms of CD34 positive (CD34+) cells mobilization and number of leukapheresis needed to collect at least one single stem cell graft. Data concerning hematopoietic recovery after ASCT were also compared. The successful mobilization rate (>2 x 10(6) CD34+ cells/kg) was comparable between de novo AML patients (87%) and those with s-AML (76%), P:0.21. No statistically significant difference was found in terms of either median number of CD34+ cells collected (P:0.44) or CD34+ cells peak in peripheral blood (P:0.28). Both groups of patients needed a median of two apheresis (P:0.45) and no difference was found on the median number of CD34+ cells collected per single apheresis (P:0.59). Finally, neutrophil and platelet recovery after ASCT were comparable between the two groups. An antecedent diagnosis of RAEB has no impact on mobilization and collection of PBSCs in AML as well as on hematopoietic recovery after ASCT.

Age has no influence on mobilization of peripheral blood stem cells in acute myeloid leukemia

The upper age limit for autologous stem cell transplantation (ASCT) in acute myeloid leukemia (AML) is increasing and peripheral blood (PB) represents the standard source of stem cell (SC). However, no data are available on the impact of age on SC mobilization in AML. We analyzed a cohort of 150 consecutive AML patients in first complete remission in order to make a comparison between patients up to 60 years and above 60 years, by evaluating CD34+ cells mobilization into PB and the number of leukapheresis needed to collect at least one single SC graft. The successful mobilization rate (>2 x 10(6) CD34+ cells/kg) was comparable between the two groups (87% vs. 80%, p = 0.29). In addition, no statistically significant difference was found in terms of either median number of CD34+ cells collected (p = 0.54) or CD34+ cells peak in PB (p = 0.70). Both groups of patients needed a median of two apheresis and no difference was found in the median number of CD34+ cells collected per single apheresis (p = 0.67). Finally, no correlation was found between age and total number of CD34+ cells collected (r = 0.003, p = 0.58). We conclude that age has no impact on mobilization of PBSCs in AML.

CXCR4 is a prognostic marker in acute myelogenous leukemia

CXCR4 chemokine receptors retain hematopoietic progenitors and leukemia cells within the marrow microenvironment. We prospectively evaluated the prognostic implication of CXCR4 in 90 consecutive patients with acute myelogenous leukemia (AML) by flow cytometry. Patients were divided into groups with low (n=32), intermediate (n=26), or high (n=32) CXCR4 expression, as defined by CXCR4 mean fluorescence intensity ratio thresholds of less than 5, 5 to 10, or more than 10, respectively. We found that low CXCR4 expression on AML cells correlated with a better prognosis, resulting in a longer relapse-free and overall survival of 24.3+/-2.9 months for low CXCR4-expressing patients, compared with 17.4+/-3.4 months for intermediate and 12.8+/-2 months (mean+/-SEM) for patients with high expression. In univariate analyses, CXCR4 expression, cytogenetics, white blood cell count, and serum lactate dehydrogenase (LDH) predicted for shorter survival. Multivariate analysis revealed CXCR4 expression and unfavorable cytogenetics as independent prognostic factors. We conclude that CXCR4 expression in AML is an independent prognostic predictor for disease relapse and survival that can rapidly and easily be determined at disease presentation. These findings warrant further investigation into the role of CXCR4 in AML and suggest that CXCR4 should be incorporated into the risk assessment of AML patients.

Significance of murine retroviral mutagenesis for identification of disease genes in human acute myeloid leukemia

Retroviral insertion mutagenesis is considered a powerful tool to identify cancer genes in mice, but its significance for human cancer has remained elusive. Moreover, it has recently been debated whether common virus integrations are always a hallmark of tumor cells and contribute to the oncogenic process. Acute myeloid leukemia (AML) is a heterogeneous disease with a variable response to treatment. Recurrent cytogenetic defects and acquired mutations in regulatory genes are associated with AML subtypes and prognosis. Recently, gene expression profiling (GEP) has been applied to further risk stratify AML. Here, we show that mouse leukemia genes identified by retroviral insertion mutagenesis are more frequently differentially expressed in distinct subclasses of adult and pediatric AML than randomly selected genes or genes located more distantly from a virus integration site. The candidate proto-oncogenes showing discriminative expression in primary AML could be placed in regulatory networks mainly involved in signal transduction and transcriptional control. Our data support the validity of retroviral insertion mutagenesis in mice for human disease and indicate that combining these murine screens for potential proto-oncogenes with GEP in human AML may help to identify critical disease genes and novel pathogenetic networks in leukemia.

Molecular typing of adult acute myeloid leukaemia: significance of translocations, tandem duplications, methylation, and selective gene expression profiling

Although a number of molecular aberrations have been described in acute myeloid leukaemia (AML), no study has yet determined their relative prognostic importance. We have analysed blast cells from 250 adult patients treated at the same institution during a 15-year period. Balanced translocations were detected by multiplex polymerase chain reaction in 13% of the cases. Internal tandem duplication (ITD) of the FLT3 gene and partial tandem duplication of the MLL gene were found in 24% and 4%, respectively. Promoter hypermethylation of the P15, CDH1, ER and MDR1 genes was observed in 71%, 64%, 40% and 4%, respectively. Compared with normal bone marrow, the chemotherapy resistance protein MRP1 and apoptosis related genes BAX and CASPASE3 were found to be overexpressed in AML blasts. Univariate analysis revealed that the most important determinants of prognosis were presence of balanced translocations, age, white blood cell count and extramedullary disease, in order of statistical significance. In a multivariate analysis, balanced translocations retained their prognostic significance and FLT3 ITD as well as high gene expression of MDR1 were negative prognostic factors. From these data, which are the first to compare these molecular aberrations directly, we conclude that, when a battery of molecular changes is evaluated for upfront significance in AML, recurrent translocations are of prime importance for treatment outcome.

Mutations in nucleophosmin (NPM1) in acute myeloid leukemia (AML): association with other gene abnormalities and previously established gene expression signatures and their favorable prognostic significance

Mutations in nucleophosmin NPM1 are the most frequent acquired molecular abnormalities in acute myeloid leukemia (AML). We determined the NPM1 mutation status in a clinically and molecularly well-characterized patient cohort of 275 patients with newly diagnosed AML by denaturing high-performance liquid chromatography (dHPLC). We show that NPM1 mutations are significantly underrepresented in patients younger than 35 years. NPM1 mutations positively correlate with AML with high white blood cell counts, normal karyotypes, and fms-like tyrosine kinase-3 gene (FLT3) internal tandem duplication (ITD) mutations. NPM1 mutations associate inversely with the occurrence of CCAAT/enhancer-binding protein-alpha (CEBPA) and NRAS mutations. With respect to gene expression profiling, we show that AML cases with an NPM1 mutation cluster in specific subtypes of AML with previously established gene expression signatures, are highly associated with a homeobox gene-specific expression signature, and can be predicted with high accuracy. We demonstrate that patients with intermediate cytogenetic risk AML without FLT3 ITD mutations but with NPM1 mutations have a significantly better overall survival (OS) and event-free survival (EFS) than those without NPM1 mutations. Finally, in multivariable analysis NPM1 mutations express independent favorable prognostic value with regard to OS, EFS, and disease-free survival (DFS).

Phase I study of oblimersen sodium, an antisense to Bcl-2, in untreated older patients with acute myeloid leukemia: pharmacokinetics, pharmacodynamics, and clinical activity

PURPOSES

Pharmacologic downregulation of Bcl-2, an antiapoptotic protein overexpressed in cancer, might increase chemosensitivity in acute myeloid leukemia (AML). Herein, we investigated the feasibility of this approach in untreated elderly AML patients by administering oblimersen sodium (G3139), an 18-mer phosphorothioate antisense to Bcl-2, during induction and consolidation treatments.

PATIENTS AND METHODS

Untreated patients with primary or secondary AML (stratified to cohort 1 or 2, respectively) who were > or = 60 years received induction with G3139, cytarabine, and daunorubicin at one of two different dose levels (45 and 60 mg/m2) and, on achievement of complete remission (CR), consolidation with G3139 and high-dose cytarabine. An enzyme-linked immunosorbent assay (ELISA)-based assay was used to measure plasma and intracellular concentrations (IC) of G3139. Bcl-2 mRNA and protein levels were quantified by real-time reverse transcriptase polymerase chain reaction and ELISA, respectively, in bone marrow samples collected before induction treatment and after 72 hours of G3139 infusion, prior to initiation of chemotherapy.

RESULTS

Of the 29 treated patients, 14 achieved CR. With a median follow-up of 12.6 months, seven patients had relapsed. Side effects of this combination were similar to those expected with chemotherapy alone and were not dose limiting at both dose levels. After 72-hour G3139 infusion, Bcl-2/ABL mRNA copies were decreased compared with baseline (P = .03) in CR patients and increased in nonresponders (NRs; P = .05). Changes in Bcl-2 protein showed a similar trend. Although plasma pharmacokinetics did not correlate with disease response, the median IC of the antisense was higher in the CR patients compared with NRs (17.0 v 4.4 pmol/mg protein, respectively; P = .05).

CONCLUSION

G3139 can be administered safely in combination with intensive chemotherapy, and the degree of Bcl-2 downmodulation may correlate with response to therapy.

Autologous bone marrow transplantation as consolidation therapy in the treatment of adult patients under 60 years with acute myeloid leukaemia in first complete remission: a prospective randomized Dutch-Belgian Haemato-Oncology Co-operative Group (HOVON) and Swiss Group for Clinical Cancer Research (SAKK) trial

The question as to whether autologous stem cell transplantation (SCT) after consolidation chemotherapy improves the probability of survival of patients with acute myeloid leukaemia (AML) in first remission has not been settled. Here, we present the results of a phase III study conducted in newly diagnosed adult AML patients aged <60 years. Patients who had reached a complete remission (CR) after two courses of induction chemotherapy and who were not eligible for a human leucocyte antigen-matched sibling SCT (n = 130), were randomized after a third consolidation cycle of chemotherapy between high-dose cytotoxic treatment and autologous bone marrow transplantation or no further treatment. No significant differences in disease-free survival and overall survival were observed between the two treatment arms. A slightly better overall survival in the no further treatment arm was because of fewer deaths in the first CR and a significantly better overall survival after the first relapse. The results are discussed in relation to the generic problems of applying autologous transplantation and in the perspective of the limited statistical power of this and other previously published studies.

Unanswered questions in acute myeloid leukaemia

Acute myeloid leukaemia (AML) is a heterogeneous disease that presents with a range of morphological, cytogenetic, immunophenotypic, and biomolecular features. Over the past 20 years, application of new cytogenetic and molecular techniques has greatly improved knowledge of the pathophysiology of AML, resulting in new potential therapeutic applications. However, the results of current therapy are still unsatisfactory, especially in patients who have adverse prognostic factors at the time of diagnosis. Furthermore, some pivotal questions about the procedures of induction and postinduction therapy of AML remain unanswered, and substantial controversy exists on the optimum therapeutic approach for the disorder.

Use of gene-expression profiling to identify prognostic subclasses in adult acute myeloid leukemia

BACKGROUND

In patients with acute myeloid leukemia (AML), the presence or absence of recurrent cytogenetic aberrations is used to identify the appropriate therapy. However, the current classification system does not fully reflect the molecular heterogeneity of the disease, and treatment stratification is difficult, especially for patients with intermediate-risk AML with a normal karyotype.

METHODS

We used complementary-DNA microarrays to determine the levels of gene expression in peripheral-blood samples or bone marrow samples from 116 adults with AML (including 45 with a normal karyotype). We used unsupervised hierarchical clustering analysis to identify molecular subgroups with distinct gene-expression signatures. Using a training set of samples from 59 patients, we applied a novel supervised learning algorithm to devise a gene-expression-based clinical-outcome predictor, which we then tested using an independent validation group comprising the 57 remaining patients.

RESULTS

Unsupervised analysis identified new molecular subtypes of AML, including two prognostically relevant subgroups in AML with a normal karyotype. Using the supervised learning algorithm, we constructed an optimal 133-gene clinical-outcome predictor, which accurately predicted overall survival among patients in the independent validation group (P=0.006), including the subgroup of patients with AML with a normal karyotype (P=0.046). In multivariate analysis, the gene-expression predictor was a strong independent prognostic factor (odds ratio, 8.8; 95 percent confidence interval, 2.6 to 29.3; P<0.001).

CONCLUSIONS

The use of gene-expression profiling improves the molecular classification of adult AML.

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

BACKGROUND

Sensitization of leukemic cells with hematopoietic growth factors may enhance the cytotoxicity of chemotherapy in acute myeloid leukemia (AML).

METHODS

In a multicenter randomized trial, we assigned patients (age range, 18 to 60 years) with newly diagnosed AML to receive cytarabine plus idarubicin (cycle 1) and cytarabine plus amsacrin (cycle 2) with granulocyte colony-stimulating factor (G-CSF) (321 patients) or without G-CSF (319). G-CSF was given concurrently with chemotherapy only. Idarubicin and amsacrin were given at the end of a cycle to allow the cell-cycle-dependent cytotoxicity of cytarabine in the context of G-CSF to have a greater effect. The effect of G-CSF on disease-free survival was assessed in all patients and in cytogenetically distinct prognostic subgroups.

RESULTS

After induction chemotherapy, the rates of response were not significantly different in the two groups. After a median follow-up of 55 months, patients in complete remission after induction chemotherapy plus G-CSF had a higher rate of disease-free survival than patients who did not receive G-CSF (42 percent vs. 33 percent at four years, P=0.02), owing to a reduced probability of relapse (relative risk, 0.77; 95 percent confidence interval, 0.61 to 0.99; P=0.04). G-CSF did not significantly improve overall survival (P=0.16). Although G-CSF did not improve the outcome in the subgroup with an unfavorable prognosis, the 72 percent of patients with standard-risk AML benefited from G-CSF therapy (overall survival at four years, 45 percent, as compared with 35 percent in the group that did not receive G-CSF [relative risk of death, 0.75; 95 percent confidence interval, 0.59 to 0.95; P=0.02]; disease-free survival, 45 percent vs. 33 percent [relative risk, 0.70]; 95 percent confidence interval, 0.55 to 0.90; P=0.006).

CONCLUSIONS

Sensitization of leukemic cells with growth factors is a clinically applicable means of enhancing the efficacy of chemotherapy in patients with AML.

Acute Myeloid Leukemia and Acute Promyelocytic Leukemia

The therapeutic approach to the patient with acute myeloid leukemia (AML) currently evolves toward new frontiers. This is particularly apparent from the entree of high-throughput diagnostic technologies and the identification of prognostic and therapeutic targets, the introduction of therapies in genetically defined subgroups of AML, as well as the influx of investigational approaches and novel drugs into the pipeline of clinical trials that target pathogenetic mechanisms of the disease.

In Section I, Dr. Bob Löwenberg reviews current issues in the clinical practice of the management of adults with AML, including those of older age. Dr. Löwenberg describes upcoming possibilities for predicting prognosis in defined subsets by molecular markers and reviews experimental strategies to improve remission induction and postinduction treatment.

In Section II, Dr. James Griffin reviews the mechanisms that lead to activation of tyrosine kinases by mutations in AML, the consequences of that activation for the cell, and the opportunities for targeted therapy and discusses some examples of developing novel drugs (tyrosine kinase inhibitors) and their effectiveness in AML (FLT3).

In Section III, Dr. Martin Tallman describes the evaluation and management of patients with acute promyelocytic leukemia, a notable example of therapeutic progress in a molecularly defined entity of leukemia. Dr. Tallman focuses on the molecular genetics of APL, current curative treatment strategies and approaches for patients with relapsed and refractory disease. In addition, areas of controversy regarding treatment are addressed.