UBTF tandem duplications define a distinct subtype of adult de novo acute myeloid leukemia.

Tandem duplications (TDs) of the UBTF gene have been recently described as a recurrent alteration in pediatric acute myeloid leukemia (AML). Here, by screening 1946 newly diagnosed adult AML, we found that UBTF-TDs occur in about 3% of patients aged 18-60 years, in a mutually exclusive pattern with other known AML subtype-defining alterations. The characteristics of 59 adults with UBTF-TD AML included young age (median 37 years), low bone marrow (BM) blast infiltration (median 25%), and high rates of WT1 mutations (61%), FLT3-ITDs (51%) and trisomy 8 (29%). BM morphology frequently demonstrates dysmyelopoiesis albeit modulated by the co-occurrence of FLT3-ITD. UBTF-TD patients have lower complete remission (CR) rates (57% after 1 course and 76% after 2 courses of intensive chemotherapy [ICT]) than UBTF-wild-type patients. In patients enrolled in the ALFA-0702 study (n = 614 patients including 21 with UBTF-TD AML), the 3-year disease-free survival (DFS) and overall survival of UBTF-TD patients were 42.9% (95%CI: 23.4-78.5%) and 57.1% (95%CI: 39.5-82.8%) and did not significantly differ from those of ELN 2022 intermediate/adverse risk patients. Finally, the study of paired diagnosis and relapsed/refractory AML samples suggests that WT1-mutated clones are frequently selected under ICT. This study supports the recognition of UBTF-TD AML as a new AML entity in adults.

Preclinical Evaluation of a Novel Small Molecule Inhibitor of LIM Kinases (LIMK) CEL_Amide in Philadelphia-Chromosome Positive (BCR::ABL+) Acute Lymphoblastic Leukemia (ALL).

Ph+ (BCR::ABL+) B-ALL was considered to be high risk, but recent advances in BCR::ABL-targeting TKIs has shown improved outcomes in combination with backbone chemotherapy. Nevertheless, new treatment strategies are needed, including approaches without chemotherapy for elderly patients. LIMK1/2 acts downstream from various signaling pathways, which modifies cytoskeleton dynamics via phosphorylation of cofilin. Upstream of LIMK1/2, ROCK is constitutively activated by BCR::ABL, and upon activation, ROCK leads to the phosphorylation of LIMK1/2, resulting in the inactivation of cofilin by its phosphorylation and subsequently abrogating its apoptosis-promoting activity. Here, we demonstrate the anti-leukemic effects of a novel LIMK1/2 inhibitor (LIMKi) CEL_Amide in vitro and in vivo for BCR::ABL-driven B-ALL. The IC50 value of CEL_Amide was ≤1000 nM in BCR::ABL+ TOM-1 and BV-173 cells and induced dose-dependent apoptosis and cell cycle arrest in these cell lines. LIMK1/2 were expressed in BCR::ABL+ cell lines and patient cells and LIMKi treatment decreased LIMK1 protein expression, whereas LIMK2 expression was unaffected. As expected, CEL_Amide exposure caused specific activating downstream dephosphorylation of cofilin in cell lines and primary cells. Combination experiments with CEL_Amide and BCR::ABL TKIs imatinib, dasatinib, nilotinib, and ponatinib were synergistic for the treatment of both TOM-1 and BV-173 cells. CDKN2Ako/BCR::ABL1+ B-ALL cells were transplanted in mice, which were treated with combinations of CEL_Amide and nilotinib or ponatinib, which significantly prolonged their survival. Altogether, the LIMKi CEL_Amide yields activity in Ph+ ALL models when combined with BCR::ABL-targeting TKIs, showing promising synergy that warrants further investigation.

Prognostic impact of DDX41 germline mutations in intensively treated acute myeloid leukemia patients: an ALFA-FILO study.

DDX41 germline mutations (DDX41MutGL) are the most common genetic predisposition to myelodysplastic syndrome and acute myeloid leukemia (AML). Recent reports suggest that DDX41MutGL myeloid malignancies could be considered as a distinct entity, even if their specific presentation and outcome remain to be defined. We describe here the clinical and biological features of 191 patients with DDX41MutGL AML. Baseline characteristics and outcome of 86 of these patients, treated with intensive chemotherapy in 5 prospective Acute Leukemia French Association/French Innovative Leukemia Organization trials, were compared with those of 1604 patients with DDX41 wild-type (DDX41WT) AML, representing a prevalence of 5%. Patients with DDX41MutGL AML were mostly male (75%), in their seventh decade, and with low leukocyte count (median, 2 × 109/L), low bone marrow blast infiltration (median, 33%), normal cytogenetics (75%), and few additional somatic mutations (median, 2). A second somatic DDX41 mutation (DDX41MutSom) was found in 82% of patients, and clonal architecture inference suggested that it could be the main driver for AML progression. DDX41MutGL patients displayed higher complete remission rates (94% vs 69%; P < .0001) and longer restricted mean overall survival censored at hematopoietic stem cell transplantation (HSCT) than 2017 European LeukemiaNet intermediate/adverse (Int/Adv) DDX41WT patients (5-year difference in restricted mean survival times, 13.6 months; P < .001). Relapse rates censored at HSCT were lower at 1 year in DDX41MutGL patients (15% vs 44%) but later increased to be similar to Int/Adv DDX41WT patients at 3 years (82% vs 75%). HSCT in first complete remission was associated with prolonged relapse-free survival (hazard ratio, 0.43; 95% confidence interval, 0.21-0.88; P = .02) but not with longer overall survival (hazard ratio, 0.77; 95% confidence interval, 0.35-1.68; P = .5).

Cystine uptake inhibition potentiates front-line therapies in acute myeloid leukemia.

By querying metabolic pathways associated with leukemic stemness and survival in multiple AML datasets, we nominated SLC7A11 encoding the xCT cystine importer as a putative AML dependency. Genetic and chemical inhibition of SLC7A11 impaired the viability and clonogenic capacity of AML cell lines in a cysteine-dependent manner. Sulfasalazine, a broadly available drug with xCT inhibitory activity, had anti-leukemic activity against primary AML samples in ex vivo cultures. Multiple metabolic pathways were impacted upon xCT inhibition, resulting in depletion of glutathione pools in leukemic cells and oxidative stress-dependent cell death, only in part through ferroptosis. Higher expression of cysteine metabolism genes and greater cystine dependency was noted in NPM1-mutated AMLs. Among eight anti-leukemic drugs, the anthracycline daunorubicin was identified as the top synergistic agent in combination with sulfasalazine in vitro. Addition of sulfasalazine at a clinically relevant concentration significantly augmented the anti-leukemic activity of a daunorubicin-cytarabine combination in a panel of 45 primary samples enriched in NPM1-mutated AML. These results were confirmed in vivo in a patient-derived xenograft model. Collectively, our results nominate cystine import as a druggable target in AML and raise the possibility to repurpose sulfasalazine for the treatment of AML, notably in combination with chemotherapy.

Machine learning identifies the independent role of dysplasia in the prediction of response to chemotherapy in AML.

The independent prognostic impact of specific dysplastic features in acute myeloid leukemia (AML) remains controversial and may vary between genomic subtypes. We apply a machine learning framework to dissect the relative contribution of centrally reviewed dysplastic features and oncogenetics in 190 patients with de novo AML treated in ALFA clinical trials. One hundred and thirty-five (71%) patients achieved complete response after the first induction course (CR). Dysgranulopoiesis, dyserythropoiesis and dysmegakaryopoiesis were assessable in 84%, 83% and 63% patients, respectively. Multi-lineage dysplasia was present in 27% of assessable patients. Micromegakaryocytes (q = 0.01), hypolobulated megakaryocytes (q = 0.08) and hyposegmented granulocytes (q = 0.08) were associated with higher ELN-2017 risk. Using a supervised learning algorithm, the relative importance of morphological variables (34%) for the prediction of CR was higher than demographic (5%), clinical (2%), cytogenetic (25%), molecular (29%), and treatment (5%) variables. Though dysplasias had limited predictive impact on survival, a multivariate logistic regression identified the presence of hypolobulated megakaryocytes (p = 0.014) and micromegakaryocytes (p = 0.035) as predicting lower CR rates, independently of monosomy 7 (p = 0.013), TP53 (p = 0.004), and NPM1 mutations (p = 0.025). Assessment of these specific dysmegakarypoiesis traits, for which we identify a transcriptomic signature, may thus guide treatment allocation in AML.

Biological Effects of BET Inhibition by OTX015 (MK-8628) and JQ1 in NPM1-Mutated (NPM1c) Acute Myeloid Leukemia (AML).

BET inhibitors (BETi) including OTX015 (MK-8628) and JQ1 demonstrated antileukemic activity including NPM1c AML cells. Nevertheless, the biological consequences of BETi in NPM1c AML were not fully investigated. Even if of better prognosis AML patients with NPM1c may relapse and treatment remains difficult. Differentiation-based therapy by all trans retinoic acid (ATRA) combined with arsenic trioxide (ATO) demonstrated activity in NPM1c AML. We found that BETi, similar to ATO + ATRA, induced differentiation and apoptosis which was TP53 independent in the NPM1c cell line OCI-AML3 and primary cells. Furthermore, BETi induced proteasome-dependent degradation of NPM1c. BETi degraded NPM1c in the cytosol while BRD4 is degraded in the nucleus which suggests that restoration of the NPM1/BRD4 equilibrium in the nucleus of NPM1c cells is essential for the efficacy of BETi. While ATO + ATRA had significant biological activity in NPM1c IMS-M2 cell line, those cells were resistant to BETi. Gene profiling revealed that IMS-M2 cells probably resist to BETi by upregulation of LSC pathways independently of the downregulation of a core BET-responsive transcriptional program. ATO + ATRA downregulated a NPM1c specific HOX gene signature while anti-leukemic effects of BETi appear HOX gene independent. Our preclinical results encourage clinical testing of BETi in NPM1c AML patients.

Genetic identification of patients with AML older than 60 years achieving long-term survival with intensive chemotherapy.

To design a simple and reproducible classifier predicting the overall survival (OS) of patients with acute myeloid leukemia (AML) ≥60 years of age treated with 7 + 3, we sequenced 37 genes in 471 patients from the ALFA1200 (Acute Leukemia French Association) study (median age, 68 years). Mutation patterns and OS differed between the 84 patients with poor-risk cytogenetics and the 387 patients with good (n = 13), intermediate (n = 339), or unmeasured (n = 35) cytogenetic risk. TP53 (hazards ratio [HR], 2.49; P = .0003) and KRAS (HR, 3.60; P = .001) mutations independently worsened the OS of patients with poor-risk cytogenetics. In those without poor-risk cytogenetics, NPM1 (HR, 0.57; P = .0004), FLT3 internal tandem duplications with low (HR, 1.85; P = .0005) or high (HR, 3.51; P < 10-4) allelic ratio, DNMT3A (HR, 1.86; P < 10-4), NRAS (HR, 1.54; P = .019), and ASXL1 (HR, 1.89; P = .0003) mutations independently predicted OS. Combining cytogenetic risk and mutations in these 7 genes, 39.1% of patients could be assigned to a "go-go" tier with a 2-year OS of 66.1%, 7.6% to the "no-go" group (2-year OS 2.8%), and 3.3% of to the "slow-go" group (2-year OS of 39.1%; P < 10-5). Across 3 independent validation cohorts, 31.2% to 37.7% and 11.2% to 13.5% of patients were assigned to the go-go and the no-go tiers, respectively, with significant differences in OS between tiers in all 3 trial cohorts (HDF [Hauts-de-France], n = 141, P = .003; and SAL [Study Alliance Leukemia], n = 46; AMLSG [AML Study Group], n = 223, both P < 10-5). The ALFA decision tool is a simple, robust, and discriminant prognostic model for AML patients ≥60 years of age treated with intensive chemotherapy. This model can instruct the design of trials comparing the 7 + 3 standard of care with less intensive regimens.

Prognostic significance of concurrent gene mutations in intensively treated patients with IDH-mutated AML: an ALFA study.

In patients with isocitrate dehydrogenase (IDH)-mutated acute myeloid leukemia (AML) treated by intensive chemotherapy (IC), prognostic significance of co-occurring genetic alterations and allogeneic hematopoietic stem cell transplantation (HSCT) are of particular interest with the advent of IDH1/2 mutant inhibitors. We retrospectively analyzed 319 patients with newly diagnosed AML (127 with IDH1, 135 with IDH2R140, and 57 with IDH2R172 mutations) treated with IC in 3 Acute Leukemia French Association prospective trials. In each IDH subgroup, we analyzed the prognostic impact of clinical and genetic covariates, and the role of HSCT. In patients with IDH1 mutations, the presence of NPM1 mutations was the only variable predicting improved overall survival (OS) in multivariate analysis (P < .0001). In IDH2R140-mutated AML, normal karyotype (P = .008) and NPM1 mutations (P = .01) predicted better OS. NPM1 mutations were associated with better disease-free survival (DFS; P = .0009), whereas the presence of DNMT3A mutations was associated with shorter DFS (P = .0006). In IDH2R172-mutated AML, platelet count was the only variable retained in the multivariate model for OS (P = .002). Among nonfavorable European LeukemiaNet 2010-eligible patients, 71 (36%) underwent HSCT in first complete remission (CR1) and had longer OS (P = .03) and DFS (P = .02) than nontransplanted patients. Future clinical trials testing frontline IDH inhibitors combined with IC may consider stratification on NPM1 mutational status, the primary prognostic factor in IDH1- or IDH2R140-mutated AML. HSCT improve OS of nonfavorable IDH1/2-mutated AML and should be fully integrated into the treatment strategy.

A personalized approach to guide allogeneic stem cell transplantation in younger adults with acute myeloid leukemia.

A multistage model instructed by a large dataset (knowledge bank [KB] algorithm) has recently been developed to improve outcome predictions and tailor therapeutic decisions, including hematopoietic stem cell transplantation (HSCT) in acute myeloid leukemia (AML). We assessed the performance of the KB in guiding HSCT decisions in first complete remission (CR1) in 656 AML patients younger than 60 years from the ALFA-0702 trial (NCT00932412). KB predictions of overall survival (OS) were superior to those of European LeukemiaNet (ELN) 2017 risk stratification (C-index, 68.9 vs 63.0). Among patients reaching CR1, HSCT in CR1, as a time-dependent covariate, was detrimental in those with favorable ELN 2017 risk and those with negative NPM1 minimal residual disease (MRD; interaction tests, P = .01 and P = .02, respectively). Using KB simulations of survival at 5 years in a scenario without HSCT in CR1 (KB score), we identified, in a similar time-dependent analysis, a significant interaction between KB score and HSCT, with HSCT in CR1 being detrimental only in patients with a good prognosis based on KB simulations (KB score ≥40; interaction test, P = .01). We could finally integrate ELN 2017, NPM1 MRD, and KB scores to sort 545 CR1 patients into 278 (51.0%) HSCT candidates and 267 (49.0%) chemotherapy-only candidates. In both time-dependent and 6-month landmark analyses, HSCT significantly improved OS in HSCT candidates, whereas it significantly shortened OS in chemotherapy-only candidates. Integrating KB predictions with ELN 2017 and MRD may thus represent a promising approach to optimize HSCT timing in younger AML patients.

Synergy of FLT3 inhibitors and the small molecule inhibitor of LIM kinase1/2 CEL_Amide in FLT3-ITD mutated Acute Myeloblastic Leukemia (AML) cells.

Patients with FLT3-ITD mutated (FLT3-ITD+) Acute Myeloid Leukemia (AML), have frequently relapsed or refractory disease and FLT3-ITD+ inhibitors have limited efficacy. Rho kinases (ROCK) are constitutively activated by FLT3-ITD+ in AML via PI3 kinase and Rho GTPase. Upon activation by ROCK, LIM kinases (LIMK) inactivate cofilin by phosphorylation which affects cytoskeleton dynamics, cell growth and apoptosis. LIMK inhibition leads to cofilin activation via dephosphorylation and activated cofilin localizes to mitochondria inducing apoptosis. Thus, we investigated the therapeutic potential of the LIMK1/2 inhibitor CEL_Amide (LIMKi) in FLT3-ITD+ AML. Expression of LIMK1/2 in FLT3-ITD+ cell lines MOLM-13 and MV-4-11 cells could be detected by RT-qPCR and at the protein level. IC50 after LIMKi monotherapy was 440 nM in MOLM-13 cells and 420 nM in MV4-11 cells. Treatment with LIMKi decreased LIMK1 protein levels and repression of inactivating phosphorylation of cofilin in FLT3-ITD+ cells. Combination experiments with LIMKi and FLT3 inhibitors including midostaurin, crenolanib and gilteritinib were synergistic for treatment of MOLM-13 cells while combinations with quizartinib were additive. Combinations of LIMKi and the hypomethylating agent azacitidine or the ROCK inhibitor fasudil were additive. In NOD-SCID mice engrafted with MOLM13-LUC cells, the FLT3 inhibitor midostaurin and LIMKi delayed MOLM13-LUC engraftment as detected by in vivo bioluminescence imaging and the LIMKi and midostaurin combination prolonged significantly survival of leukemic mice. LIMK1/2 inhibition by the small molecule CEL_Amide seems to have promising activity in combination with FLT3 inhibitors in vitro as well as in vivo and may constitute a novel treatment strategy for FLT3-ITD+ AML.

Added prognostic value of secondary AML-like gene mutations in ELN intermediate-risk older AML: ALFA-1200 study results.

In this study, we aimed to refine prognostication of older with acute myeloid leukemia (AML) after intensive chemotherapy. Five hundred and nine patients aged 60 years or older (median age, 68 years) were prospectively enrolled in the intensive Acute Leukemia French Association (ALFA)-1200 trial between 2012 and 2016, and 471 patient samples were submitted to multigene analysis. Mutations in any of 8 genes frequently altered in myelodysplastic syndromes (MDS), including ASXL1, SRSF2, STAG2, BCOR, U2AF1, EZH2, SF3B1, and ZRSR2, defined a secondary AML (sAML)-like disease, as reported. Of the samples analyzed, 48% included sAML-like gene mutations. These mutations were associated with a shorter event-free survival, both overall (hazard ratio, 1.46; 95% confidence interval, 1.19-1.79; P < .001) and within the European LeukemiaNet (ELN)-2017 intermediate-risk subgroup (hazard ratio, 1.52; 95% confidence interval, 1.01-2.28; P = .044), which excludes ASXL1-mutated cases by definition. We therefore included patients with intermediate-risk AML carrying sAML-like mutations in a single high-risk patients group together with adverse-risk patients with AML, whereas other intermediate-risk patients were included in a standard-risk group together with favorable-risk patients (high-risk/standard-risk patient ratio, 1.00). Using this 2-class risk assessment, we observed that transplantation prolonged overall survival from remission in patients with high-risk AML only, not in patients with standard-risk AML. Routine analysis of sAML-like gene mutations may thus improve the definition of high-risk older patients with AML, and better identify the half of older patients who clearly derive survival benefit from allogeneic transplantation in first remission. This trial was registered at www.clinicaltrials.gov as #NCT01966497.

BET inhibitors impair leukemic stem cell function only in defined oncogenic subgroups of acute myeloid leukaemias.

Bromodomain and Extra-Terminal inhibitors (BETi) such as OTX015 are active in Acute Myeloid Leukaemias (AML). Their activity on Leukemic Stem Cells (LSCs) is less documented. We interrogated the anti-LSC activity of OTX015 in a niche-like long-term culture in 26 primary AML samples and validated our findings in vivo. OTX015 impaired LSCs in AMLs harbouring Core Binding Factor or KMT2A gene fusions, NPM1 or chromatin/spliceosome genes mutations, but not in those with aneuploidy/TP53 mutations. In four patients, we dissected the transcriptomic footprint of Bet inhibition on LSCs versus blasts. Our results can instruct future clinical trials of BETi in AML.

Gemtuzumab ozogamicin for de novo acute myeloid leukemia: final efficacy and safety updates from the open-label, phase III ALFA-0701 trial.

The randomized, phase III ALFA-0701 trial showed that a reduced and fractionated dose of gemtuzumab ozogamicin added to standard front-line chemotherapy significantly improves event-free survival (EFS) in adults with de novo acute myeloid leukemia (AML). Here we report an independent review of EFS, final overall survival (OS), and additional safety results from ALFA-0701. Patients (n=271) aged 50-70 years with de novo AML were randomized to receive conventional front-line induction chemotherapy (3+7daunorubicin+cytarabine) with/without gemtuzumab ozogamicin 3 mg/m2 on days 1, 4, and 7 during induction. Patients in remission following induction therapy received 2 courses of consolidation therapy (daunorubicin+cytarabine) with/without gemtuzumab ozogamicin (3 mg/m2/day on day 1) according to their initial randomization. The primary end point was investigator-assessed EFS. Secondary end points included OS and safety. A blinded independent review confirmed the investigator-assessed EFS results [August 1, 2011; hazard ratio (HR) 0.66; 95% Confidence Interval (CI): 0.49-0.89; 2-sided P=0.006], corresponding to a 34% reduction in risk of events in the gemtuzumab ozogamicin versus control arm. Final OS at April 30, 2013 favored gemtuzumab ozogamicin but was not significant. No differences in early death rate were observed between arms. The main toxicity associated with gemtuzumab ozogamicin was prolonged thrombocytopenia. Veno-occlusive disease (including after transplant) was observed in 6 patients in the gemtuzumab ozogamicin arm and 2 in the control arm. In conclusion, gemtuzumab ozogamicin added to standard intensive chemotherapy has a favorable benefit/risk ratio. These results expand front-line treatment options for adult patients with previously untreated AML. (Trial registered at clinicaltrials.gov; identifier: 00927498).

Arsenic trioxide is required in the treatment of newly diagnosed acute promyelocytic leukemia. Analysis of a randomized trial (APL 2006) by the French Belgian Swiss APL group.

In standard-risk acute promyelocytic leukemia, recent results have shown that all-trans retinoic acid plus arsenic trioxide combinations are at least as effective as classical all-trans retinoic acid plus anthracycline-based chemotherapy while being less myelosuppressive. However, the role of frontline arsenic trioxide is less clear in higher-risk acute promyelocytic leukemia, and access to arsenic remains limited for front-line treatment of standard-risk acute promyelocytic leukemia in many countries. In this randomized trial, we compared arsenic, all-trans retinoic acid and the "classical" cytarabine for consolidation treatment (after all-trans retinoic acid and chemotherapy induction treatment) in standard-risk acute promyelocytic leukemia, and evaluated the addition of arsenic during consolidation in higher-risk disease. Patients with newly diagnosed acute promyelocytic leukemia with a white blood cell count <10x109/L, after an induction treatment consisting of all-trans retinoic acid plus idarubicin and cytarabine, received consolidation chemotherapy with idarubicin and cytarabine, arsenic or all-trans retinoic acid. Patients with a white blood cell count >10x109/L received consolidation chemotherapy with or without arsenic. Overall, 795 patients with acute promyelocytic leukemia were enrolled in this trial. Among those with standard-risk acute promyelocytic leukemia (n=581), the 5-year event-free survival rates from randomization were 88.7%, 95.7% and 85.4% in the cytarabine, arsenic and all-trans retinoic acid consolidation groups, respectively (P=0.0067), and the 5-year cumulative incidences of relapse were was 5.5%, 0% and 8.2%. (P=0.001). Among those with higher-risk acute promyelocytic leukemia (n=214), the 5-year event-free survival rates were 85.5% and 92.1% (P=0.38) in the chemotherapy and chemotherapy plus arsenic groups, respectively, and the corresponding 5-year cumulative incidences of relapse were 4.6% and 3.5% (P=0.99). Given the prolonged myelosuppression that occurred in the chemotherapy plus arsenic arm, a protocol amendment excluded cytarabine during consolidation cycles in the chemotherapy plus arsenic group, resulting in no increase in relapse. Our results therefore advocate systematic introduction of arsenic in the first-line treatment of acute promyelocytic leukemia, but probably not concomitantly with intensive chemotherapy, a situation in which we found myelosuppression to be significant. (ClinicalTrials.gov Identifier: NCT00378365).

Real life experience with frontline azacitidine in a large series of older adults with acute myeloid leukemia stratified by MRC/LRF score: results from the expanded international E-ALMA series (E-ALMA+).

Azacitidine (AZA) prolonged overall survival (OS) in the AZA-AML-001 trial. However, few subjects were randomized to AZA or intensive chemotherapy (IC). The Medical Research Council (MRC) and the Leukemia Research Foundation (LRF) developed a score for older AML patients receiving IC or non-intensive regimens, whereas the E-ALMA study validated a score for survival and response in elderly patients receiving AZA in daily practice. Both identified three groups with different risk estimates. This analysis evaluates the efficacy of frontline AZA in older AML patients (N = 710) unfit for IC from different national registries (E-ALMA + series) stratified by the MRC/LRF risk score. Median OS of patients categorized as good, standard and poor-risk groups by the MRC/LRF score was 13.4 (95% CI, 10.8-16), 12.4 (95% CI, 9.9-14.8), and 8.1 months (95% CI, 7-9.1), respectively (p = .0001). In conclusion, this is the largest retrospective cohort of older AML patients treated with AZA.

Investigational BET bromodomain protein inhibitors in early stage clinical trials for acute myelogenous leukemia (AML).

INTRODUCTION: Acute myelogenous leukemia (AML) is a heterogeneous group of malignancies driven by genetic mutations and deregulated epigenetic control. Relapse/refractory disease remains frequent in younger patients and even more so in older patients, including treatment with epigenetic drugs in this age group, mainly with hypomethylating agents. New treatment strategies are urgently needed. The recent discovery that epigenetic readers of the bromodomain (BRD) and extraterminal (BET) protein family, are crucial for AML maintenance by transcription of oncogenic c-MYC lead to rapid development of BET inhibitors entering clinical trials. Areas covered: We provide a critical overview using main sources for the use of BET inhibitors in AML treatment. Limits of this treatment approach including resistance mechanisms and future directions including development of new generation BET inhibitors and combination strategies with other drugs are detailed. Expert opinion: BET inhibitors were expected to overcome limits of conventional treatment in patients as impressive in vitro data emerged recently in well-characterized AML subsets, including those associated with poor risk characteristics in the clinic. Nevertheless single activity of BET inhibitors appears to be modest and resistance mechanisms were already identified. BET inhibitors with alternative mechanisms of action and/or combination strategies with epigenetic drugs should be tested.

Hypomethylating Agents as a Therapy for AML.

Acute myeloid leukemia (AML) is predominantly a disease of older adults associated with poor long-term outcomes with available therapies. Used as single agents, hypomethylating agents (HMAs) induce only 15 to 25% complete remissions, but current data suggest that median OS observed after HMAs is comparable to that observed after more intensive therapies. Whether long-term cure may be obtained in some patients treated with HMAs is unknown. Combinations of HMAs to novel agents are now extensively investigated and attractive response rates have been reported when combining HMAs to different drug classes. The absence of reliable predictive biomarkers of efficacy of HMAs in AML and the uncertainties regarding their most relevant mechanisms of action hinder the rational design of the combinations to be tested in priority, usually in untreated older AML patients.

Lenalidomide combined with intensive chemotherapy in acute myeloid leukemia and higher-risk myelodysplastic syndrome with 5q deletion. Results of a phase II study by the Groupe Francophone Des Myélodysplasies.

Patients with acute myeloblastic leukemia or higher risk myelodysplastic syndromes with 5q deletion (generally within a complex karyotype) respond poorly to intensive chemotherapy and have very poor survival. In this population, we evaluated escalating doses of lenalidomide combined with intensive chemotherapy in a phase II study. Treatment consisted of daunorubicin (45 mg/m2/day, days 1-3 in cohort 1, escalated to 60 mg/m2/day, days 1-3 in cohorts 2 and 3) combined with cytosine arabinoside (200 mg/m2/day, days 1-7) and lenalidomide (10 mg/day, days 1-21 in cohorts 1 and 2, escalated to 25 mg/day, days 1-21 in cohort 3). Eighty-two patients with 5q deletion were enrolled, including 62 with acute myeloblastic leukemia, 62/79 (78%) of whom had a complex karyotype (median 7 cytogenetic abnormalities, all but 2 of them monosomal) and three had unknown karyotypes. Thirty-eight patients (46%) achieved complete remission and the overall response rate was 58.5%. Among the 62 patients with a complex karyotype, 27 achieved complete remission (44%) and 21 had cytogenetic responses. A lower response rate was observed in patients with acute myeloblastic leukemia but other pretreatment factors, including cytogenetic complexity and treatment cohort, did not significantly influence response. Fifteen patients underwent allogeneic stem cell transplantation, including 11 patients in first remission. The 1-year cumulative incidence of relapse was 64.6% and the median overall survival was 8.2 months. By comparison with conventional intensive chemotherapy, the treatment protocol we used appeared to produce higher hematologic and cytogenetic complete remission rates in patients with very poor cytogenetics, but response duration was short in this very poor risk population, highlighting the need for better post-induction strategies. Clinical trial registry number: NCT00885508.