Dyserythropoiesis evaluated by the RED score and hepcidin:ferritin ratio predicts response to erythropoietin in lower-risk myelodysplastic syndromes

Erythropoiesis-stimulating agents are generally the first line of treatment of anemia in patients with lower-risk myelodysplastic syndrome. We prospectively investigated the predictive value of somatic mutations, and biomarkers of ineffective erythropoiesis including the flow cytometry RED score, serum growth-differentiation factor-15, and hepcidin levels. Inclusion criteria were no prior treatment with erythropoiesis-stimulating agents, low- or intermediate-1-risk myelodysplastic syndrome according to the International Prognostic Scoring System, and a hemoglobin level <10 g/dL. Patients could be red blood cell transfusion-dependent or not and were given epoetin zeta 40 000 IU/week. Serum erythropoietin level, iron parameters, hepcidin, flow cytometry Ogata and RED scores, and growth-differentiation factor-15 levels were determined at baseline, and molecular analysis by next-generation sequencing was also conducted. Erythroid response (defined according to the International Working Group 2006 criteria) was assessed at week 12. Seventy patients, with a median age of 78 years, were included in the study. There were 22 patients with refractory cytopenia with multilineage dysplasia, 19 with refractory cytopenia with unilineage dysplasia, 14 with refractory anemia with ring sideroblasts, four with refractory anemia with excess blasts-1, six with chronic myelomonocytic leukemia, two with del5q-and three with unclassifiable myelodysplastic syndrome. According to the revised International Prognostic Scoring System, 13 had very low risk, 47 had low risk, nine intermediate risk and one had high-risk disease. Twenty patients were transfusion dependent. Forty-eight percent had an erythroid response and the median duration of the response was 26 months. At baseline, non-responders had significantly higher RED scores and lower hepcidin:ferritin ratios. In multivariate analysis, only a RED score >4 (P=0.05) and a hepcidin:ferritin ratio <9 (P=0.02) were statistically significantly associated with worse erythroid response. The median response duration was shorter in patients with growth-differentiation factor-15 >2000 pg/mL and a hepcidin:ferritin ratio <9 (P=0.0008 and P=0.01, respectively). In multivariate analysis, both variables were associated with shorter response duration. Erythroid response to epoetin zeta was similar to that obtained with other erythropoiesis-stimulating agents and was correlated with higher baseline hepcidin:ferritin ratio and lower RED score. ClinicalTrials.gov registration: NCT 03598582.

Abstract 1785: Pre-clinical development of a novel CD3-CD123 bispecific T-cell engager using Cross-Over-Dual-Variable-Domain (CODV) format for the treatment of acute myeloid leukemia (AML)

Acute myeloid leukemia (AML) is characterized by the accumulation of abnormal blast cells in the bone marrow and blood. While high intensity chemotherapy and allogeneic stem cell transplantation cure a subset of patients with AML, many patients are ineligible or do not respond sufficiently to these therapies. One potential reason for treatment failure in a particular patient may be the inability to reach and eliminate residual leukemic stem cells (LSCs) located in the bone marrow. T-cell mediated cytotoxicity, targeting LSCs with high expression of certain leukemic antigens, represents an attractive therapeutic strategy for relapsed and refractory AML. In this study, the proprietary Cross-Over-Dual-Variable-Domain (CODV) format was applied to a fully humanized IgG1 backbone with reduced Fc functionality, resulting in a bispecific T-cell engager (TCE), CD123-CODV-TCE, that binds to both CD3 on T cells and CD123 (α-chain of the interleukin-3 receptor) on AML blasts and LSCs. CD123-CODV-TCE displayed high affinity for human CD123 and medium affinity for human CD3 proteins. As expected, CD123-CODV-TCE activated CD4-positive and CD8-positive T cells only in the presence of cells expressing the CD123 target, such as THP1 (an AML tumor cell line), and induced killing of these cells with an EC50 in a picomolar range. Potential cytotoxic activity of CD123-CODV-TCE was also evaluated on CD123-expressing normal blood cells such as plasmacytoid dendritic cells (pDC) and monocytes. CD123-CODV-TCE was shown to deplete pDC and monocyte from human Healthy Donor (HD) Peripheral Blood Mononuclear Cells (PBMC) with an EC50 in the picomolar range. This efficacy correlated with the release of numerous cytokines, thus highlighting the potential risk of cytokine release syndrome as described for other TCE's. In an in vivo disseminated AML model using CD123+ Molm13-luc human AML cell line, treatment of the mice with CD123-CODV-TCE suppressed AML tumor growth in the bone marrow compartment following co-injection of primary human T cells. In this murine pre-clinical model, CD123-CODV-TCE displayed favorable pharmacokinetic properties with a terminal half-life of 3 days. To investigate CD123-CODV-TCE activity on myeloid blast cells and LSC, in vivo efficacy studies were performed in NSG mice injected with primary human AML cells obtained from patients. In this model, CD123-CODV-TCE induced the killing of primary AML cells by activating human autologous T cells. Taken together, these results indicate that CD123-CODV-TCE can potently and specifically kill CD123+ leukemic cancer cells in vitro and in vivo. CD123-CODV-TCE therefore represents a potential candidate for future clinical development in relapsed and refractory AML.

Citation Format: Helene Bonnevaux, Stephane Guerif, Jana Albrecht, Erwan Jouannot, Laurent Bassinet, Agnès Vergezac, Christian Beil, Christian Lange, Wulf Dirk Leuschner, Anne Caron, Celine Amara, Cedric Barriere, Justine Siavellis, Valerie Bardet, Ernesto Luna, Donald Drake, Ercole Rao, Corina Oprea, Peter Wonerow, Chantal Carrez, Veronique Blanc, Karl Hsu, Dmitri Wiederschain, Paula G. Fraenkel. Pre-clinical development of a novel CD3-CD123 bispecific T-cell engager using Cross-Over-Dual-Variable-Domain (CODV) format for the treatment of acute myeloid leukemia (AML) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1785.

In vivo and in vitro sensitivity of blastic plasmacytoid dendritic cell neoplasm to SL-401, an interleukin-3 receptor targeted biologic agent

Blastic plasmacytoid dendritic cell neoplasm is an aggressive malignancy derived from plasmacytoid dendritic cells. There is currently no accepted standard of care for treating this neoplasm, and therapeutic strategies have never been prospectively evaluated. Since blastic plasmacytoid dendritic cell neoplasm cells express high levels of interleukin-3 receptor α chain (IL3-Rα or CD123), antitumor effects of the interleukin-3 receptor-targeted drug SL-401 against blastic plasmacytoid dendritic cell neoplasm were evaluated in vitro and in vivo. The cytotoxicity of SL-401 was assessed in patient-derived blastic plasmacytoid dendritic cell neoplasm cell lines (CAL-1 and GEN2.2) and in primary blastic plasmacytoid dendritic cell neoplasm cells isolated from 12 patients using flow cytometry and an in vitro cytotoxicity assay. The cytotoxic effects of SL-401 were compared to those of several relevant cytotoxic agents. SL-401 exhibited a robust cytotoxicity against blastic plasmacytoid dendritic cell neoplasm cells in a dose-dependent manner. Additionally, the cytotoxic effects of SL-401 were observed at substantially lower concentrations than those achieved in clinical trials to date. Survival of mice inoculated with a blastic plasmacytoid dendritic cell neoplasm cell line and treated with a single cycle of SL-401 was significantly longer than that of untreated controls (median survival, 58 versus 17 days, P<0.001). These findings indicate that blastic plasmacytoid dendritic cell neoplasm cells are highly sensitive to SL-401, and support further evaluation of SL-401 in patients suffering from blastic plasmacytoid dendritic cell neoplasm.

Schistocytes in disseminated intravascular coagulation

INTRODUCTION

The presence of schistocytes on the peripheral blood film during disseminated intravascular coagulation (DIC) remains controversial.

METHODS

We examined schistocytes count on blood films from 35 DIC patients and checked morphological anomalies of all RBCs.

RESULTS

Thirty of 35 patients presented with schistocytes and 22 with acanthocytes, which was the commonest shape anomaly. Mean percentage ± standard deviation was 0.33 ± 0.38%, median value was 0.1%, and range was 0-1.4%. The patients with schistocytes ≥ 1% had circumstances frequently associated with increased schistocytes count (promyelocytic leukaemia, pregnancy, severe infection).

DISCUSSION

Schistocytes were thus frequently observed in DIC patients, usually with low percentage, within or close to the reference range (<0.5%). Schistocytes measurement is not a clue test for the initial diagnosis of DIC, but might be of clinical value to suggest an associated or underlying thrombotic microangiopathy if ≥ 1%.

High levels of CD34+CD38low/-CD123+ blasts are predictive of an adverse outcome in acute myeloid leukemia: a Groupe Ouest-Est des Leucemies Aigues et Maladies du Sang (GOELAMS) study

BACKGROUND

Acute myeloid leukemias arise from a rare population of leukemic cells, known as leukemic stem cells, which initiate the disease and contribute to frequent relapses. Although the phenotype of these cells remains unclear in most patients, these cells are enriched within the CD34(+)CD38(low/-) compartment expressing the interleukin-3 alpha chain receptor, CD123. The aim of this study was to determine the prognostic value of the percentage of blasts with the CD34(+)CD38(low/-)CD123(+) phenotype.

DESIGN AND METHODS

The percentage of CD34(+)CD38(low/-)CD123(+) cells in the blast population was determined at diagnosis using flow cytometry. One hundred and eleven patients under 65 years of age with de novo acute myeloid leukemia and treated with intensive chemotherapy were retrospectively included in the study. Correlations with complete response, disease-free survival and overall survival were evaluated with univariate and multivariate analyses.

RESULTS

A proportion of CD34(+)CD38(low/-)CD123(+) cells greater than 15% at diagnosis and an unfavorable karyotype were significantly correlated with a lack of complete response. By logistic regression analysis, a percentage of CD34(+)CD38(low/-)CD123(+) higher than 15% retained significance with an odds ratio of 0.33 (0.1-0.97; P=0.044). A greater than 1% population of CD34(+)CD38(low/-)CD123(+) cells negatively affected disease-free survival (0.9 versus 4.7 years; P<0.0001) and overall survival (1.25 years versus median not reached; P<0.0001). A greater than 1% population of CD34(+)CD38(low/-)CD123(+) cells retained prognostic significance for both parameters after multivariate analysis.

CONCLUSIONS

The percentage of CD34(+)CD38(low/-)CD123(+) leukemic cells at diagnosis was significantly correlated with response to treatment and survival. This prognostic marker might be easily adopted in clinical practice to rapidly identify patients at risk of treatment failure.

Dual inhibition of PI3K and mTORC1/2 signaling by NVP-BEZ235 as a new therapeutic strategy for acute myeloid leukemia

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.

Perspectives on inhibiting mTOR as a future treatment strategy for hematological malignancies

Mammalian target of rapamycin (mTOR) is a protein kinase implicated in the regulation of various cellular processes, including those required for tumor development, such as the initiation of mRNA translation, cell-cycle progression and cellular proliferation. In a wide range of hematological malignancies, the mTORC1 signaling pathway has been found to be deregulated and has been designed as a major target for tumor therapy. Given that pre-clinical studies have clearly established the therapeutic value of mTORC1 inhibition, numerous clinical trials of rapamycin and its derivates (rapalogs) are ongoing for treatment of these diseases. At this time, although disease stabilization and tumor regression have been observed, objective responses in some tumor types have been modest. Nevertheless, some of the mechanisms underlying cancer-cell resistance to rapamycin have now been described, thereby leading to the development of new strategy to efficiently target mTOR signaling in these diseases. In this review, we discuss the rationale for using mTOR inhibitors as novel therapies for a variety of hematological, malignancies with a focus on promising new perspectives for these approaches.

Targeting translation in acute myeloid leukemia: a new paradigm for therapy?

The mammalian Target Of Rapamycin Complex 1 (mTORC1) pathway is commonly activated in cancer cells including acute myeloid leukemia (AML) and has been designed as a major target for cancer therapy. However, the efficacy of rapalogs (mTORC1 inhibitors) is limited in AML, due to the feedback activation of PI3K or ERK signaling pathways upon mTORC1 inhibition, which pathways should be simultaneously targeted to enhance the anti-leukemic activity of rapalogs. Moreover, the mRNA translation process is mTORC1-independent in AML, although markedly contributing to oncogenesis in this disease, and this also strongly participates to rapalogs resistance. Translation inhibition could be achieved by directly targeting the translation initiating complex using the 4EGI-1 compound, anti-eIF4E antisense oligonucleotides or the antiviral drug ribavirin or by second generation mTOR inhibitors (TORkinhibs). These new approaches represent promising perspectives for AML therapy that should have clinical development in the future.

Le syndrome MYH9 : à propos d'une nouvelle observation et de la mise en évidence d'une nouvelle mutation du gène MYH9

INTRODUCTION

Familial macrothrombocytopenias are a group of rare autosomal dominant platelet disorders including many syndromes in particular the May-Hegglin anomaly. They are characterized by thrombocytopenia with giant platelets and in some cases neutrophilic inclusions in peripheral blood granulocytes. Recently these different clinical entities have been demonstrated to be linked to mutations in the same gene, MYH9.

CASE REPORT

We report in a young African woman presenting as a May-Hegglin anomaly a new mutation of the MYH9 gene. In regard of this case we present a brief review of the MYH9 syndrome.

CONCLUSION

The MYH9 syndrome includes now several clinical entities who share some common clinical and biological characteristics such as a thrombocytopenia with giant platelets, presence or absence of other manifestations including Dohle like bodies, nephritis, sensorineural hearing loss, cataract. We report a new case in which a new mutation of the MYH9 gene was evidenced.

Essential role for the p110 isoform in phosphoinositide 3-kinase activation and cell proliferation in acute myeloid leukemia

The phosphoinositide 3-kinase (PI3K)/Akt signaling pathway has been shown to be frequently activated in blast cells from patients with acute myeloid leukemia (AML) and to contribute to survival and proliferation of these cells. Of the 8 distinct mammalian isoforms of PI3K, it is the class I PI3Ks (p110alpha, p110beta, p110gamma, and p110delta) that are responsible for Akt activation. It is not known which PI3K isoform is critical in AML. Here we show that the p110delta isoform of PI3K is consistently expressed at a high level in blast cells from AML, in contrast to the other class I isoforms, the expression of which was very variable among patients. IC87114, a p110delta-selective inhibitor, suppressed both constitutive and Flt-3-stimulated Akt activation in blasts to the same extent as Ly294002, an inhibitor of all PI3K isoforms. Moreover, IC87114 inhibited AML cell proliferation without affecting the proliferation of normal hematopoietic progenitor cells. These observations identify p110delta as a potential therapeutic target in AML.

Mapping of chromosome 20 for loss of heterozygosity in childhood ALL reveals a 1,000-kb deletion in one patient

The long arm of chromosome 20 displays recurrent loss of heterozygosity (LOH) for microsatellite markers in blast cells from children with acute lymphoblastic leukemia. To further characterize the region of deletion and to precisely establish its frequency, we searched for LOH in 103 children with ALL using polymorphic markers in the previously described region of interest, namely between D20S101 and D20S887. LOH was detected in nine patients (ie with a frequency of 8.7%). Interestingly, in one patient, a small deletion was found, flanked proximally by D20S850 and distally by M201, a dinucleotide repeat identified from chromosome 20 sequences. The distance between these two markers is approximately 1000 kb. The occurrence of non-random deletions of the long arm of chromosome 20 has previously been observed in myeloid malignancies (myeloproliferative disorders and myelodysplastic syndromes) in 5-10% of patients. The small deletion in our patient is located within the common region of deletion of myeloproliferative disorders suggesting that a tumor suppressor gene may be the common target of the deletions in various types of hematological malignancies.