H Döhner

Phase III study of all-trans retinoic acid in previously untreated patients 61 years or older with acute myeloid leukemia.

The purpose of our study was (i) to evaluate the impact of all-trans retinoic acid (ATRA) given as adjunct to chemotherapy and (ii) to compare second consolidation vs maintenance therapy in elderly patients with acute myeloid leukemia (AML). A total of 242 patients aged ⩾61 years (median, 66.6 years) with AML were randomly assigned to ATRA beginning on day +3 after the initiation of chemotherapy (ATRA-arm, n=122) or no ATRA (standard-arm, n=120) in combination with induction and first consolidation therapy. A total of 61 patients in complete remission (CR) were randomly assigned to second intense consolidation (n=31) or 1-year oral maintenance therapy (n=30). After induction therapy the intention-to-treat analysis revealed a significant difference in CR rates between the ATRA- and the standard-arm (52 vs 39%; P=0.05). Event-free (EFS) and overall survival (OS) were significantly better in the ATRA-compared to the standard-arm (P=0.03 and 0.01, respectively). OS after second randomization was significantly better for patients assigned to intensive consolidation therapy (P<0.001). The multivariate model for survival revealed lactate dehydrogenase, cytogenetic risk group, age, and first and second randomization as prognostic variables. In conclusion, the addition of ATRA to induction and consolidation therapy may improve CR rate, EFS and OS in elderly patients with AML.

DNMT3A mutations in myeloproliferative neoplasms

Since the discovery of the gain-of-function mutation JAK2 V617F in 2005, an increasing number of mutations have been described in myeloproliferative neoplasms (MPN) and related myeloid malignancies.1, 2, 3, 4 For instance, use of array-based techniques such as comparative genomic hybridization and single-nucleotide polymorphism (SNP) analysis led to the identification of genes involved in epigenetic regulation such as tet-oncogene family member 2 (TET2), additional sex combs like 1 (ASXL1) and enhancer of zeste 2 (EZH2).5, 6, 7 Inactivating mutations in TET2, ASXL1 and EZH2 are considered to promote myeloid tumorigenesis because of epigenetic modulation of target genes. More recently, a whole-genome sequencing study in acute myeloid leukemia (AML) uncovered recurrent mutations in 22% of AML patients in another epigenetic regulator, the DNA methyltransferase 3A gene DNMT3A.8 In this study, DNMT3A mutations were associated with poor outcome and, thus, are of clinical relevance. However, exact mechanisms of action of DNMT3A mutations are still unclear because global methylation patterns and 5-methylcytosine content in AML genomes were not significantly altered. Nevertheless, mutations of TET2, ASXL1, EZH2 and DNMT3A occur in a significant number of patients with myeloid malignancies underlining the pathogenic relevance of epigenetic changes.

Risk-adapted postremission therapy in acute myeloid leukemia: results of the german multicenter AML HD93 treatment trial

The objective of the AML HD93 treatment trial was to evaluate the outcome in young adults with acute myeloid leukemia (AML) after postremission therapy was stratified according to cytogenetically defined risk. The rationales for the study design were based (i) on previous favorable results with high-dose cytarabine in AML with t(8;21), inv/t(16q22) and in AML with normal karyotype, and ii) on encouraging results obtained in several phase II trials using autologous stem cell transplantation (SCT). Between July 1993 and January 1998, 223 eligible patients, 16–60 years of age with newly diagnosed AML other than French–American–British type M3/M3v, were entered into the trial. Risk groups were defined as follows: low risk: t(8;21) or inv/t(16q22); intermediate risk: normal karyotype; high risk: all other chromosomal abnormalities. Following intensive double induction therapy with idarubicin, cytarabine and etoposide, all patients in complete remission (CR) received a first consolidation therapy with high-dose cytarabine and mitoxantrone (HAM). A second consolidation therapy was stratified according to the risk group: low risk: HAM; intermediate risk: related allogeneic SCT or sequential HAM; high risk: related allogeneic or autologous SCT. Double induction therapy resulted in a high CR rate of 74.5%, and 90% of the responding patients were eligible for consolidation therapy. Survival for all 223 trial entrants was 40%, and for the 166 patients who entered CR, disease-free (DFS) and overall survival were 40 and 51% after 5 years, respectively. Within the low-, intermediate- and high-risk groups, DFS and survival after 5 years were 62.5 and 87, 40 and 49 and 17 and 26% respectively, without advantage for allogeneic transplantation in the intermediate- and high-risk groups. Postremission therapy-related mortality was 0, 7 and 14%, respectively. This study demonstrates the feasibility of cytogenetically defined risk-adapted consolidation therapy. The overall trial results are at least equivalent to those of published trials supporting the risk-adapted treatment strategy.

Recurrent finding of the FIP1L1-PDGFRA fusion gene in eosinophilia-associated acute myeloid leukemia and lymphoblastic T-cell lymphoma

The FIP1L1-PDGFRA fusion gene has been described in patients with eosinophilia-associated myeloproliferative disorders (Eos-MPD). Here, we report on seven FIP1L1-PDGFRA-positive patients who presented with acute myeloid leukemia (AML, n=5) or lymphoblastic T-cell non-Hodgkin-lymphoma (n=2) in conjunction with AML or Eos-MPD. All patients were male, the median age was 58 years (range, 40–66). AML patients were negative for common mutations of FLT3, NRAS, NPM1, KIT, MLL and JAK2; one patient revealed a splice mutation of RUNX1 exon 7. Patients were treated with imatinib (100u2009mg, n=5; 400u2009mg, n=2) either as monotherapy (n=2), as maintenance treatment after intensive chemotherapy (n=3) or in overt relapse 43 and 72 months, respectively, after primary diagnosis and treatment of FIP1L1-PDGFRA-positive disease (n=2). All patients are alive, disease-free and in complete hematologic and complete molecular remission after a median time of 20 months (range, 9–36) on imatinib. The median time to achievement of complete molecular remission was 6 months (range, 1–14). We conclude that all eosinophilia-associated hematological malignancies should be screened for the presence of the FIP1L1-PDGFRA fusion gene as they are excellent candidates for treatment with tyrosine kinase inhibitors even if they present with an aggressive phenotype such as AML.

Gene expression profiling in AML with normal karyotype can predict mutations for molecular markers and allows novel insights into perturbed biological pathways.

Gene expression profiling in AML with normal karyotype can predict mutations for molecular markers and allows novel insights into perturbed biological pathways

Intensive consolidation versus oral maintenance therapy in patients 61 years or older with acute myeloid leukemia in first remission: results of second randomization of the AML HD98-B treatment trial

Intensive consolidation versus oral maintenance therapy in patients 61 years or older with acute myeloid leukemia in first remission: results of second randomization of the AML HD98-B treatment Trial

Molecular profiling reveals myeloid leukemia cell lines to be faithful model systems characterized by distinct genomic aberrations

To model and investigate different facets of leukemia pathogenesis, a widely accepted approach is to use immortalized leukemia cell lines. Although these provide powerful tools to our knowledge, few studies have addressed the question whether hematopoietic cell lines represent accurate and reliable model systems. To improve the molecular characterization of these model systems, we analyzed 17 myeloid leukemia cell lines using DNA microarray technology. By array-based comparative genomic hybridization, we identified recurrent genomic DNA gains and losses, as well as high-level amplifications. Parallel analysis of gene expression helped delineate potential candidate genes, and unsupervised analysis of gene expression data revealed cell lines to cluster in part based on underlying cytogenetic abnormalities. Comparison with clinical leukemia specimens showed that key signatures were retained, as myeloid cell lines with characteristic cytogenetic aberrations co-clustered with leukemia samples carrying the respective abnormality. Signatures were also quite robust, as expression data from cell lines correlated highly with published data. Thus, our analyses demonstrate myeloid cell lines to exhibit conserved and stable signatures reflecting the underlying primary cytogenetic aberrations. Our refined molecular characterization of myeloid cell lines supports the utility of cell lines as faithful and powerful model systems and provides additional insights into the molecular mechanisms of leukemogenesis.

Deregulated apoptosis signaling in core-binding factor leukemia differentiates clinically relevant, molecular marker-independent subgroups

Core-binding factor (CBF) leukemias, characterized by translocations t(8;21) or inv(16)/t(16;16) targeting the CBF, constitute acute myeloid leukemia (AML) subgroups with favorable prognosis. However, about 40% of patients relapse and the current classification system does not fully reflect this clinical heterogeneity. Previously, gene expression profiling (GEP) revealed two distinct CBF leukemia subgroups displaying significant outcome differences and identified apoptotic signaling, MAPKinase signaling and chemotherapy-resistance mechanisms among the most significant differentially regulated pathways. We now tested different inhibitors of the respective pathways in a cell line model (six cell lines reflecting the CBF subgroup-specific gene expression alterations), and found apoptotic signaling to be differentiating between the CBF subgroup models. In accordance, primary samples from newly diagnosed CBF AML patients (n=23) also showed differential sensitivity to in vitro treatment with a Smac mimetic such as BV6, an antagonist of inhibitor of apoptosis (IAP) proteins, and ABT-737, a BCL2 inhibitor. Furthermore, GEP revealed the BV6-resistant cases to resemble the previously identified unfavorable CBF subgroup. Thus, our current findings show deregulated IAP expression and apoptotic signaling to differentiate clinically relevant CBF subgroups, which were independent of known molecular markers, thereby providing a starting point for novel therapeutic approaches.

The German competence network 'Acute and chronic leukemias'

R Hehlmann, U Berger, C Aul, Th Büchner, H Döhner, G Ehninger, A Ganser, N Gökbuget, D Hoelzer, K Überla, W Gassmann, WD Ludwig, H Rieder, M Kneba, A Hochhaus, A Reiter, W Hiddemann, OG Ottmann, U Germing, K Adelhard, M Dugas, P Dirschedl, D Messerer, A Böhme, E Harrison-Neu, M Griesshammer, J Kienast, HJ Kolb, AD Ho, M Hallek, A Neubauer, B Schlegelberger, D Niederwieser, G Heil, T Müller and J Hasford Kompetenznetz ‘Akute und chronische Leukämien’, III. Medizinische Universitätsklinik, Klinikum Mannheim der Universität Heidelberg, Mannheim, Germany

Pomalidomide in myeloproliferative neoplasm-associated myelofibrosis

Myeloproliferative neoplasm (MPN)-associated myelofibrosis is a MPN characterized by bone marrow fibrosis, cytopenias, splenomegaly and constitutional symptoms. Pomalidomide, an immune-modifying drug, is reported to improve anaemia and thrombocytopenia in some patients with MPN-associated myelofibrosis. We designed a phase 2 study of pomalidomide in patients with MPN-associated myelofibrosis and anaemia and/or thrombocytopenia and/or neutropenia. Subjects received pomalidomide 2.0u2009mg/day in cohort 1 (n=38) or 0.5u2009mg/day in cohort 2 (n=58). Prednisolone was added if there was no response after 3 months in cohort 1 and based on up-front randomization in cohort 2 if there was no response at 3 or 6 months. Response rates were 39% (95% confidence interval (CI), 26–55%) in cohort 1 and 24% (95% CI, 15–37%) in cohort 2. In a multivariable logistic regression model pomalidomide at 2.0u2009mg/day (odds ratio (OR), 2.62; 95% CI, 1.00–6.87; P=0.05) and mutated TET2 (OR, 5.07; 95% CI, 1.16–22.17; P=0.03) were significantly associated with responses. Median duration of responses was 13.0 months (range 0.9–52.7). There was no significant difference in response rates or duration in subjects receiving or not receiving prednisolone. Clinical trial MPNSG 01-09 is registered at ClinicalTrials.gov (NCT00949364) and clinicaltrialsregister.eu (EudraCT Number: 2009-010738-23)