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Background: CPX-351, an encapsulated form of cytarabine and daunorubicin, has shown greater efficacy than the classic 3 + 7 treatment administration in secondary acute myeloid leukaemia. Given that higher-risk myelodysplastic syndrome and chronic myelomonocytic leukaemia share similarities with secondary acute myeloid leukaemia, we aimed to investigate the safety and efficacy of CPX-351 in this context., Methods: This investigator-initiated two-cohort phase 2 trial was conducted by the Groupe Francophone des Myélodysplasies, with 12 participating centres in France. It comprised cohort A (reported here and completed), which included patients in first-line treatment, and cohort B, which was stopped for lack of inclusion (ie, not enough patients met the inclusion criteria), for patients with hypomethylating agent failure that is not reported here. Cohort A enrolled patients with newly diagnosed higher-risk myelodysplastic syndrome or chronic myelomonocytic leukaemia (aged 18-70 years old) with an Eastern Cooperative Oncology Group performance status of 0-1. Intravenous CPX-351 (100 mg/m 2 cytarabine and 44 mg/m 2 daunorubicin) was given on days 1, 3, and 5, with a second induction cycle given (same daily dose on days 1 and 3) if at least a partial response was not reached. Patients who responded could receive up to four monthly consolidation cycles (same daily dose on day 1) or allogeneic haematopoietic stem-cell transplantation (HSCT). Overall response rate after one or two induction courses according to European LeukemiaNet 2017 acute myeloid leukaemia was the primary endpoint after CPX-351 induction, whether patients received one or two induction cycles. Safety was assessed in all patients enrolled (in cohort A). This trial is registered with ClinicalTrials.gov, NCT04273802., Findings: Between April 29, 2020, and Feb 10, 2021, 21 (68%) male and ten (32%) female patients were enrolled. 27 (87%) of 31 patients responded (95% CI 70-96). 16 (52%) of the 31 patients received at least one consolidation cycle. 30 (97%) of the 31 patients included were initially considered eligible for allogeneic HSCT and 29 (94%) of the 31 patients had the procedure. Median follow-up was 16·1 months (IQR 8·3-18·1). The most common grade 3-4 adverse events were pulmonary (eight [26%] of 31 patients) and cardiovascular (six [19%] of 31 patients). There were 14 serious adverse events (mainly hospitalisation for infection [n=5] and only one was treatment-related) and no treatment-related death., Interpretation: CPX-351 appears to be active and safe in patients with higher-risk myelodysplastic syndrome and chronic myelomonocytic leukaemia, allowing bridging to allogenic HSCT in most patients., Funding: Jazz Pharmaceuticals., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

In order to improve the outcome observed with azacitidine (AZA) in higher-risk Myelodysplastic syndrome (MDS), its combination with other drugs in MDS must be evaluated. So far, no combination has not been shown to be more effective than AZA alone. AZA-PLUS was a phase II trial that, in a "pick a winner" approach, randomly assigned patients with higher-risk MDS, CMML and low blast count AML to: AZA; AZA plus lenalidomide; AZA plus Valproic Acid or AZA plus Idarubicin. 322 patients were included. After six cycles, 69 (21.4%) CR + PR were observed with no benefit from any combination. Median EFS and OS were 17.2 and 19.7 months in the whole cohort, respectively, with no difference across randomised arms. Infection and rates of hospitalisation during the first six cycles were higher in the AZA-LEN And AZA-IDA arm, related to increased myelosuppression. Factors associated with better response were IPSS, favourable or intermediate karyotype, haemoglobin, lower circulating blast count, fibrinogen level and lower LDH, while poorer survival was seen in therapy-related MDS and, in the case of TP53, PTPN11 or CSF3R mutation. The combinations used did not improve the outcome obtained with AZA alone. However, our "pick a winner" randomised strategy may remain useful with potentially more active drugs to be tested in combination with AZA., (© 2022 British Society for Haematology and John Wiley & Sons Ltd.)

High-risk myelodysplastic syndrome/acute myeloid leukemia patients have a very poor survival after azacitidine failure. Guadecitabine (SGI-110) is a novel subcutaneous hypomethylating agent which results in extended decitabine exposure. This multicenter phase II study evaluated the efficacy and safety of guadecitabine in high-risk myelodysplastic syndrome and low blast count acute myeloid leukemia patients refractory or relapsing after azacitidine. We included 56 patients with a median age of 75 years [Interquartile Range (IQR) 69-76]. Fifty-five patients received at least one cycle of guadecitabine (60 mg/m2/d subcutaneously days 1-5 per 28-day treatment cycles), with a median of 3 cycles (range, 0-27). Eight (14.3%) patients responded, including two complete responses; median response duration was 11.5 months. Having no or few identified somatic mutations was the only factor predicting response ( P =0.035). None of the 11 patients with TP53 mutation responded. Median overall survival was 7.1 months, and 17.9 months in responders (3 of whom had overall survival >2 years). In multivariate analysis, IPSS-R (revised International Prognostic Scoring System) score other than very high ( P =0.03) primary versus secondary azacitidine failure ( P =0.01) and a high rate of demethylation in blood during the first cycle of treatment ( P =0.03) were associated with longer survival. Thus, guadecitabine can be effective, sometimes yielding relatively prolonged survival, in a small proportion of high-risk myelodysplastic syndrome/low blast count acute myeloid leukemia patients who failed azacitidine. (Trial registered a t clinicaltrials.gov identifier: 02197676 )., (Copyright© 2019 Ferrata Storti Foundation.)

Purpose Most anemic patients with non-deleted 5q lower-risk myelodysplastic syndromes (MDS) are treated with erythropoiesis-stimulating agents (ESAs), with a response rate of approximately 50%. Second-line treatments, including hypomethylating agents (HMAs), lenalidomide (LEN), and investigational drugs, may be used after ESA failure in some countries, but their effect on disease progression and overall survival (OS) is unknown. Here, we analyzed outcome after ESA failure and the effect of second-line treatments. Patients and Methods We examined an international retrospective cohort of 1,698 patients with non-del(5q) lower-risk MDS treated with ESAs. Results Erythroid response to ESAs was 61.5%, and median response duration was 17 months. Of 1,147 patients experiencing ESA failure, 653 experienced primary failure and 494 experienced relapse after a response. Primary failure of ESAs was associated with a higher risk of acute myeloid leukemia (AML) progression, which did not translate into an OS difference. Of 450 patients (39%) who received second-line treatment, 194 received HMAs, 148 received LEN, and 108 received other treatments (MISC), whereas 697 received RBC transfusions only. Five-year AML cumulative incidence was 20.3%, 20.3%, and 11.3% for those receiving HMAs, LEN, and MISC, respectively ( P = .05). Five-year OS for patients receiving HMA, LEN, and MISC was 36.5%, 41.7%, and 51%, respectively ( P = .21). In a multivariable analysis adjusted for age, sex, revised International Prognostic Scoring System score, and progression at ESA failure, there was no significant OS difference among the three groups. Conclusion In this large, multicenter, retrospective cohort of patients with non-del(5q) lower-risk MDS treated with ESAs, none of the most commonly used second-line treatments (HMA and LEN) significantly improved OS. Early failure of ESAs was associated with a higher risk of AML progression.

Dysregulation of the Wnt/β-catenin pathway has been observed in various malignancies, including acute myeloid leukemia (AML), where the overexpression of β-catenin is an independent adverse prognostic factor. β-catenin was found upregulated in the vast majority of AML samples and more frequently localized in the nucleus of leukemic stem cells compared with normal bone marrow CD34(+) cells. The knockdown of β-catenin, using a short hairpin RNA (shRNA) lentiviral approach, accelerates all-trans retinoic acid-induced differentiation and impairs the proliferation of HL60 leukemic cell line. Using in vivo quantitative tracking of these cells, we observed a reduced engraftment potential after xenotransplantation when β-catenin was silenced. However, when studying primary AML cells, despite effective downregulation of β-catenin we did not observe any impairment of their in vitro long-term maintenance on MS-5 stroma nor of their engraftment potential in vivo. Altogether, these results show that despite a frequent β-catenin upregulation in AML, leukemia-initiating cells might not be 'addicted' to this pathway and thus targeted therapy against β-catenin might not be successful in all patients.

Finding an effective treatment for acute myeloid leukemia (AML) remains a challenge, and all cellular processes that are deregulated in AML cells should be considered in the design of targeted therapies. We show in our current study that the LKB1/AMPK/TSC tumor suppressor axis is functional in AML and can be activated by the biguanide molecule metformin, resulting in a specific inhibition of mammalian target of rapamycin (mTOR) catalytic activity. This induces a multisite dephosphorylation of the key translation regulator, 4E-BP1, which markedly inhibits the initiation step of mRNA translation. Consequently, metformin reduces the recruitment of mRNA molecules encoding oncogenic proteins to the polysomes, resulting in a strong antileukemic activity against primary AML cells while sparing normal hematopoiesis ex vivo and significantly reducing the growth of AML cells in nude mice. The induction of the LKB1/AMPK tumor-suppressor pathway thus represents a promising new strategy for AML therapy.

The FOXO transcription factors are involved in multiple signaling pathways and have tumor-suppressor functions. In acute myeloid leukemia (AML), deregulation of oncogenic kinases, including Akt, extra-signal-regulated kinase, or IκB kinase, is frequently observed, which may potentially inactivate FOXO activity. We therefore investigated the mechanism underlying the regulation of FOXO3a, the only FOXO protein constantly expressed in AML blast cells. We show that in both primary AML samples and in a MV4-11/FOXO3a-GFP cell line, FOXO3a is in a constant inactive state due to its cytoplasmic localization, and that neither PI3K/Akt nor extra-signal-regulated kinase-specific inhibition resulted in its nuclear translocation. In contrast, the anti-Nemo peptide that specifically inhibits IKK activity was found to induce FOXO3a nuclear localization in leukemic cells. Furthermore, an IKK-insensitive FOXO3a protein mutated at S⁶⁴⁴ translocated into the nucleus and activated the transcription of the Fas-L and p21(Cip1) genes. This, in turn, inhibited leukemic cell proliferation and induced apoptosis. These results thus indicate that IKK activity maintains FOXO3a in the cytoplasm and establishes an important role of FOXO3a inactivation in the proliferation and survival of AML cells. The restoration of FOXO3a activity by interacting with its subcellular distribution may thus represent a new attractive therapeutic strategy for AML.

Purpose: The growth and survival of acute myeloid leukemia (AML) cells are enhanced by the deregulation of signaling pathways such as phosphoinositide 3-kinase (PI3K)/Akt and mammalian target of rapamycin (mTOR). Major efforts have thus been made to develop molecules targeting these activated pathways. The mTOR serine/threonine kinase belongs to two separate complexes: mTORC1 and mTORC2. The mTORC1 pathway is rapamycin sensitive and controls protein translation through the phosphorylation of 4E-BP1 in most models. In AML, however, the translation process is deregulated and rapamycin resistant. Furthermore, the activity of PI3K/Akt and mTOR is closely related, as mTORC2 activates the oncogenic kinase Akt. We therefore tested, in this study, the antileukemic activity of the dual PI3K/mTOR ATP-competitive inhibitor NVP-BEZ235 compound (Novartis)., Experimental Design: The activity of NVP-BEZ235 was tested in primary AML samples (n = 21) and human leukemic cell lines. The different signaling pathways were analyzed by Western blotting. The cap-dependent mRNA translation was studied by 7-methyl-GTP pull-down experiments, polysomal analysis, and [(3)H]leucine incorporation assays. The antileukemic activity of NVP-BEZ235 was tested by analyzing its effects on leukemic progenitor clonogenicity, blast cell proliferation, and survival., Results: The NVP-BEZ235 compound was found to inhibit PI3K and mTORC1 signaling and also mTORC2 activity. Furthermore, NVP-BEZ235 fully inhibits the rapamycin-resistant phosphorylation of 4E-BP1, resulting in a marked inhibition of protein translation in AML cells. Hence, NVP-BEZ235 reduces the proliferation rate and induces an important apoptotic response in AML cells without affecting normal CD34(+) survival., Conclusions: Our results clearly show the antileukemic efficiency of the NVP-BEZ235 compound, which therefore represents a promising option for future AML therapies., (©2010 AACR.)

The PI3K/AKT and mTOR signaling pathways are activated in acute myeloid leukemia, including in the more immature leukemic populations. Constitutive PI3K activation is detectable in 50% of acute myeloid leukemia samples whereas mTORC1 is activated in all cases of this disease. In leukemic cells, the PI3K activity relates to the expression of the p110delta isoform of class IA PI3K. Constitutive PI3K activation is the result of autocrine IGF-1/IGF-1R signaling in 70% of acute myeloid leukemia samples but specific inhibition of this pathway does not induce apoptosis. Specific inhibition of PI3K/AKT or mTORC1 alone in vitro has anti-leukemic effects which are essentially exerted via the suppression of proliferation. However, as mTORC1 activation is independent of PI3K/AKT in acute myeloid leukemia, dual PI3K and mTOR inhibitors may induce apoptosis in blast cells. Moreover, mTORC1 inhibition using sirolimus overactivates PI3K/AKT via the upregulation of IRS2 expression and by favoring IGF-1/IGF-1R autocrine signaling. Recent data also indicate that mTORC1 does not control protein translation in acute myeloid leukemia. These results open the way for the design of direct inhibitors of protein synthesis as novel acute myeloid leukemia therapies and also for the development of second generation mTOR inhibitors (the TORKinhibs).

Background: Alterations in the PI3K/Akt pathway are found in a wide range of cancers and the development of PI3K inhibitors represents a promising approach to cancer therapy. Constitutive PI3K activation, reflecting an intrinsic oncogenic deregulation of primary blast cells, is detected in 50% of patients with acute myeloid leukemia. However, the mechanisms leading to this activation are currently unknown. As we previously reported IGF-1 autocriny in acute myeloid leukemia cells, we investigated whether IGF-1 signaling was involved in the constitutive activation of PI3K., Design and Methods: We analyzed the IGF-1/IGF-1R signaling pathway and PI3K activity in 40 acute myeloid leukemia bone marrow samples. Specific inhibition of IGF-1/IGF-1R signaling was investigated using neutralizing anti-IGF-1R, anti-IGF-1 antibodies or IGF-1 short interfering RNA. The anti-leukemic activity of the neutralizing anti-IGF-1R was tested by analyzing its effects on leukemic progenitor clonogenicity, blast cell proliferation and survival., Results: In all samples tested, we found that functional IGF-1R was constantly expressed in leukemic cells. In the acute myeloid leukemia samples with PI3K activation, we found that the IGF-1R was constitutively phosphorylated, although no IGF-1R activating mutation was detected. Specific inhibition of IGF-1R signaling with neutralizing anti-IGF-1R strongly inhibited the constitutive phosphorylation of both IGF-1R and Akt in 70% of the PI3K activated samples. Moreover, both incubation with anti-IGF-1 antibody and IGF-1 short interfering RNA inhibited Akt phosphorylation in leukemic cells. Finally, neutralizing anti-IGF-1R treatment decreased the clonogenicity of leukemic progenitors and the proliferation of PI3K activated acute myeloid leukemia cells., Conclusions: Our current data indicate a critical role for IGF-1 autocriny in constitutive PI3K/Akt activation in primary acute myeloid leukemia cells and provide a strong rationale for targeting IGF-1R as a potential new therapy for this disease.

The deregulation of translation markedly contributes to the malignant phenotype in cancers, and the assembly of the translation initiating complex eIF4F is the limiting step of this process. The mammalian Target of Rapamycin Complex 1 (mTORC1) is thought to positively regulate eIF4F assembly and subsequent oncogenic protein synthesis through 4E-BP1 phosphorylation. We showed here that the translation inhibitor 4EGI-1 decreased the clonogenic growth of leukemic progenitors and induced apoptosis of blast cells, with limited toxicity against normal hematopoiesis, which emphasize the importance of translation deregulation in acute myeloid leukemia (AML) biology. However, the mTORC1 inhibitor RAD001 (a rapamycin derivate) did not induce AML blast cell apoptosis. We herein demonstrated that mTORC1 disruption using raptor siRNA or RAD001 failed to inhibit 4E-BP1 phosphorylation in AML. Moreover, RAD001 failed to inhibit eIF4F assembly, to decrease the proportion of polysome-bound c-Myc mRNA, and to reduce the translation-dependent accumulation of oncogenic proteins. We identified the Pim-2 serine/threonine kinase as mainly responsible for 4E-BP1 phosphorylation on the S(65) residue and subsequent translation control in AML. Our results strongly implicate an mTORC1-independent deregulation of oncogenic proteins synthesis in human myeloid leukemogenesis. Direct inhibition of the translation initiating complex thus represents an attractive option for the development of new therapies in AML.

The phosphatidylinositol 3-kinase (PI3K)/Akt and mTORC1 pathways are frequently activated, representing potential therapeutic targets in acute myeloid leukemia (AML). In 19 AML samples with constitutive PI3K/Akt activation, the rapamycin derivative inhibitor everolimus (RAD001) increased Akt phosphorylation. This mTOR C1-mediated Akt up-regulation was explained by an insulin-like growth factor-1 (IGF-1)/IGF-1 receptor autocrine loop: (1) blast cells expressed functional IGF-1 receptors, and IGF-1-induced Akt activation was increased by RAD001, (2) a neutralizing anti-IGF-1R alpha-IR3 monoclonal antibody reversed the RAD001-induced Akt phosphorylation, and (3) autocrine production of IGF-1 was detected in purified blast cells by quantitative reverse transcription-polymerase chain reaction and immunofluorescence. This RAD001-induced PI3K/Akt up-regulation was due to an up-regulated expression of the IRS2 adaptor. Finally, we observed that concomitant inhibition of mTORC1 and PI3K/Akt by RAD001 and IC87114 induced additive antiproliferative effects. Our results suggest that dual inhibition of the mTORC1 complex and the IGF-1/IGF-1R/PI3K/Akt pathway in AML may enhance the efficacy of mTOR inhibitors in treatment of this disease.

The phosphoinositide 3-kinase (PI3K/Akt) pathway is activated in acute myelogenous leukemia (AML) and is promising for targeted inhibition. Ninety-two patients with primary AML were analyzed for PI3K/Akt constitutive activation. Fifty percent of the patients presented with constitutive PI3K activation (PI3K (+)). No difference was observed between PI3K (+) and PI3K (-) groups concerning age, sex, white blood cell count, lactate dehydrogenase (LDH) level, bone marrow blast cells, French-American-British (FAB) classification, cytogenetics, RAS or nucleophosmin (NPM) mutations. Slightly more FLT3-ITD was detected in the PI3K (-) group (P = .048). The complete remission rate was similar between the 2 groups. With a median follow-up of 26 months, we observed for PI3K (+) and PI3K (-) patients, respectively, 56% and 33% overall survival (P = .001) and 72% and 41% relapse-free survival (P = .001). Constitutive PI3K/Akt activity is a favorable prognosis factor in AML, even after adjustment for FLT3-ITD, and may confer a particular sensitivity to chemotherapy. A better understanding of the downstream effectors of the PI3K/Akt pathway is needed before targeting in AML.