Anna Jonasova

Cyclosporin A therapy in hypoplastic MDS patients and certain refractory anaemias without hypoplastic bone marrow

We report 17 cytopenic patients with myelodysplastic syndrome (MDS) of refractory anaemia (RA) subtype with hyper‐, normo‐ or hypo‐cellular bone marrow (BM), who were treated with cyclosporin A (CyA). Substantial haematological response was observed in 14 patients (82%): their anaemia improved and all transfusion‐dependent patients achieved transfusion independence. Complete trilineage recovery was observed in four patients (23%). The CyA therapy has not yet failed in any of the 14 successfully treated patients during follow‐up times ranging from 5 to 30 months. CyA was well tolerated in 14 patients; serious side‐effects required termination of the therapy in three patients in whom the blood count rapidly deteriorated to former levels upon cessation of therapy. Two patients benefited from a combination therapy of CyA and erythropoietin. Six patients experienced various autoimmune phenomena. CyA could thus offer an alternative treatment for certain MDS patients with RA regardless of hyper‐, normo‐ or hypo‐cellularity of bone marrow (BM). The mechanism of the beneficial effect of CyA is discussed and remains the subject of an ongoing study.

Epigenetic silencing of the oncogenic miR-17-92 cluster during PU.1-directed macrophage differentiation.

The oncogenic cluster miR‐17‐92 encodes seven related microRNAs that regulate cell proliferation, apoptosis and development. Expression of miR‐17‐92 cluster is decreased upon cell differentiation. Here, we report a novel mechanism of the regulation of miR‐17‐92 cluster. Using transgenic PU.1−/− myeloid progenitors we show that upon macrophage differentiation, the transcription factor PU.1 induces the secondary determinant Egr2 which, in turn, directly represses miR‐17‐92 expression by recruiting histone demethylase Jarid1b leading to histone H3 lysine K4 demethylation within the CpG island at the miR‐17‐92 promoter. Conversely, Egr2 itself is targeted by miR‐17‐92, indicating existence of mutual regulatory relationship between miR‐17‐92 and Egr2. Furthermore, restoring EGR2 levels in primary acute myeloid leukaemia blasts expressing elevated levels of miR‐17‐92 and low levels of PU.1 and EGR2 leads to downregulation of miR‐17‐92 and restored expression of its targets p21CIP1 and BIM. We propose that upon macrophage differentiation PU.1 represses the miR‐17‐92 cluster promoter by an Egr‐2/Jarid1b‐mediated H3K4 demethylation mechanism whose deregulation may contribute to leukaemic states.

Randomized Phase III Study of Lenalidomide Versus Placebo in RBC Transfusion-Dependent Patients With Lower-Risk Non-del(5q) Myelodysplastic Syndromes and Ineligible for or Refractory to Erythropoiesis-Stimulating Agents

PURPOSE This international phase III, randomized, placebo-controlled, double-blind study assessed the efficacy and safety of lenalidomide in RBC transfusion-dependent patients with International Prognostic Scoring System lower-risk non-del(5q) myelodysplastic syndromes ineligible for or refractory to erythropoiesis-stimulating agents. PATIENTS AND METHODS In total, 239 patients were randomly assigned (2:1) to treatment with lenalidomide (n = 160) or placebo (n = 79) once per day (on 28-day cycles). The primary end point was the rate of RBC transfusion independence (TI) ≥ 8 weeks. Secondary end points were RBC-TI ≥ 24 weeks, duration of RBC-TI, erythroid response, health-related quality of life (HRQoL), and safety. RESULTS RBC-TI ≥ 8 weeks was achieved in 26.9% and 2.5% of patients in the lenalidomide and placebo groups, respectively (P < .001). Ninety percent of patients achieving RBC-TI responded within 16 weeks of treatment. Median duration of RBC-TI with lenalidomide was 30.9 weeks (95% CI, 20.7 to 59.1). Transfusion reduction of ≥ 4 units packed RBCs, on the basis of a 112-day assessment, was 21.8% in the lenalidomide group and 0% in the placebo group. Higher response rates were observed in patients with lower baseline endogenous erythropoietin ≤ 500 mU/mL (34.0% v 15.5% for > 500 mU/mL). At week 12, mean changes in HRQoL scores from baseline did not differ significantly between treatment groups, which suggests that lenalidomide did not adversely affect HRQoL. Achievement of RBC-TI ≥ 8 weeks was associated with significant improvements in HRQoL (P < .01). The most common treatment-emergent adverse events were neutropenia and thrombocytopenia. CONCLUSION Lenalidomide yields sustained RBC-TI in 26.9% of RBC transfusion-dependent patients with lower-risk non-del(5q) myelodysplastic syndromes ineligible for or refractory to erythropoiesis-stimulating agents. Response to lenalidomide was associated with improved HRQoL. Treatment-emergent adverse event data were consistent with the known safety profile of lenalidomide.

5-Azacitidine in aggressive myelodysplastic syndromes regulates chromatin structure at PU.1 gene and cell differentiation capacity

Epigenetic 5-azacitidine (AZA) therapy of high-risk myelodysplastic syndromes (MDS) and acute myelogenous leukemia (AML) represents a promising, albeit not fully understood, approach. Hematopoietic transcription factor PU.1 is dynamically regulated by upstream regulatory element (URE), whose deletion causes downregulation of PU.1 leading to AML in mouse. In this study a significant group of the high-risk MDS patients, as well as MDS cell lines, displayed downregulation of PU.1 expression within CD34+ cells, which was associated with DNA methylation of the URE. AZA treatment in vitro significantly demethylated URE, leading to upregulation of PU.1 followed by derepression of its transcriptional targets and onset of myeloid differentiation. Addition of colony-stimulating factors (CSFs; granulocyte-CSF, granulocyte–macrophage-CSF and macrophage-CSF) modulated AZA-mediated effects on reprogramming of histone modifications at the URE and cell differentiation outcome. Our data collectively support the importance of modifying the URE chromatin structure as a regulatory mechanism of AZA-mediated activation of PU.1 and induction of the myeloid program in MDS.

Efficacy And Safety Of Administration Of Oral Iron Chelator Deferiprone In Patients With Early Myelodysplastic Syndrome

Forty-eight patients with early myelodysplastic syndrome (MDS) without excess of blasts, with average initial serum ferritin levels of 2739.5 μg/L (range 825–11287 μg/L), were treated with deferiprone (L1) in a daily dose of 40–90 mg/kg. Median duration of chelation treatment was 10.9 months (range 4–24 months). Chelation was effective (maintained or decreased iron stores) in 16 out of 22 patients (73%) with serum ferritin levels <2000 μg/L in contrast to only 12 out of 26 patients with serum ferritin levels >2000 μg/L. Combination of L1 with recombinant human erythropoietin (rHuEPO) (30–40 kU/week) resulted in effective chelation in five additional patients with serum ferritin levels >3000 μg/L. Incidence of adverse effects was comparable to that in thalassemic patients. Gastrointestinal symptoms represented the most frequent adverse effect of L1 therapy (37.5% of patients) that limited an effective escalation of the daily dose of the drug and led to discontinuation of the treatment for six patients. A decreased number of granulocytes was observed in five (13%) patients and agranulocytosis occurred in two patients (4%). Granulocyte counts were restored after cessation of L1 treatment and administration of granulocyte colony stimulating factor (G-CSF) in all but one patient. Administration of L1 in a daily dose of at least 75 mg/kg may represent an alternative approach in treatment of mild and moderate iron overload in MDS patients who cannot be treated with deferasirox (DFRA) or deferoxamine (DFO).

Prevalence, severity and correlates of fatigue in newly diagnosed patients with myelodysplastic syndromes

The primary objective of this study was to investigate factors associated with fatigue severity in newly diagnosed patients with higher‐risk myelodysplastic syndromes (MDS). The secondary objectives were to assess symptom prevalence and to examine the relationships between fatigue, quality of life (QoL) and overall symptom burden in these patients. The analyses were conducted in 280 higher‐risk MDS patients. Pre‐treatment patient‐reported fatigue was evaluated with the Functional Assessment of Chronic Illness Therapy (FACIT)‐Fatigue scale and QoL was assessed with the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire‐Core 30 (EORTC QLQ‐C30). Female gender (P = 0·018), poor performance status (i.e., ECOG of 2–4) (P < 0·001) and lower levels of haemoglobin (Hb) (P = 0·026) were independently associated with higher fatigue severity. The three most prevalent symptoms were as follows: fatigue (92%), dyspnoea (63%) and pain (55%). Patients with higher levels of fatigue also had greater overall symptom burdens. The mean global QoL scores of patients with the highest versus those with the lowest levels of fatigue were 29·2 [standard deviation (SD), 18·3] and 69·0 (SD, 18·8), respectively and this difference was four times the magnitude of a clinically meaningful difference. Patient‐reported fatigue severity revealed the effects of disease burden on overall QoL more accurately than did degree of anaemia. Special attention should be given to the female patients in the management of fatigue.

A comparative study of deferasirox and deferiprone in the treatment of iron overload in patients with myelodysplastic syndromes

One hundred thirteen patients with myelodysplastic syndromes (MDS) with <10% of bone marrow blasts received either deferiprone in a daily dose of 40-90 mg/kg (48 patients) or deferasirox in a daily dose of 10-40 mg/kg (65 patients). Median duration of treatment was 10,9 months for deferiprone and 13,7 months for deferasirox. A substantial reduction of iron stores evaluated as a decrease in serum ferritin of more than 50% of pretreatment level was achieved in 18 patients in deferasirox group (27.7%) but not in any patient treated with deferiprone, The incidence of adverse effects (mostly gastrointestinal symptoms) was similar after administration of both the drugs. The symptoms of deferasirox toxicity were mild and mostly transient and no drug related myelosuppresive effect was observed in contrast to deferiprone where agranulocytosis occurred in 4% of patients and the treatment had to be discontinued due to side effects in 20% of patients. The results confirmed the usefulness of deferasirox as an effective and safe iron chelator in MDS patients and indication of deferiprone as an alternative treatment only in patients with mild or moderate iron overload clearly not indicated for deferasirox.

High level of full-length cereblon mRNA in lower risk myelodysplastic syndrome with isolated 5q deletion is implicated in the efficacy of lenalidomide

Downregulation of cereblon (CRBN) gene expression is associated with resistance to the immunomodulatory drug lenalidomide and poor survival outcomes in multiple myeloma (MM) patients. However, the importance of CRBN gene expression in patients with myelodysplastic syndrome (MDS) and its impact on lenalidomide therapy are not clear. In this study, we evaluate cereblon expression in mononuclear cells isolated from bone marrow [23 lower risk MDS patients with isolated 5q deletion (5q‐), 37 lower risk MDS patients with chromosome 5 without the deletion of long arms (non‐5q‐), and 24 healthy controls] and from peripheral blood (38 patients with 5q‐, 52 non‐5q‐ patients and 25 healthy controls) to gain insight into, firstly, the role of cereblon in lower risk MDS patients with or without 5q deletion and, secondly, into the mechanisms of lenalidomide action. Patients with 5q‐ lower risk MDS have the highest levels of CRBN mRNA in comparison with both lower risk MDS without the deletion of long arms of chromosome 5 and healthy controls. CRBN gene expression was measured using the quantitative TaqMan real‐time PCR. High levels of CRBN mRNA were detected in all lenalidomide responders during the course of therapy. A significant decrease of the CRBN mRNA level during lenalidomide treatment is associated with loss of response to treatment and disease progression. These results suggest that, similar to the treatment of MM, high levels of full‐length CRBN mRNA in lower risk 5q‐ patients are necessary for the efficacy of lenalidomide.

Aggressive acute myeloid leukemia in PU.1/p53 double-mutant mice.

PU.1 downregulation within hematopoietic stem and progenitor cells (HSPCs) is the primary mechanism for the development of acute myeloid leukemia (AML) in mice with homozygous deletion of the upstream regulatory element (URE) of PU.1 gene. p53 is a well-known tumor suppressor that is often mutated in human hematologic malignancies including AML and adds to their aggressiveness; however, its genetic deletion does not cause AML in mouse. Deletion of p53 in the PU.1ure/ure mice (PU.1ure/urep53−/−) results in more aggressive AML with shortened overall survival. PU.1ure/urep53−/− progenitors express significantly lower PU.1 levels. In addition to URE deletion we searched for other mechanisms that in the absence of p53 contribute to decreased PU.1 levels in PU.1ure/urep53−/− mice. We found involvement of Myb and miR-155 in downregulation of PU.1 in aggressive murine AML. Upon inhibition of either Myb or miR-155 in vitro the AML progenitors restore PU.1 levels and lose leukemic cell growth similarly to PU.1 rescue. The MYB/miR-155/PU.1 axis is a target of p53 and is activated early after p53 loss as indicated by transient p53 knockdown. Furthermore, deregulation of both MYB and miR-155 coupled with PU.1 downregulation was observed in human AML, suggesting that MYB/miR-155/PU.1 mechanism may be involved in the pathogenesis of AML and its aggressiveness characterized by p53 mutation.

Involvement of deleted chromosome 5 in complex chromosomal aberrations in newly diagnosed myelodysplastic syndromes (MDS) is correlated with extremely adverse prognosis

MDS with complex chromosomal aberrations (CCA) are characterized by short survival and a high rate of transformation to AML. A comprehensive genome-wide analysis of bone-marrow cells of 157 adults with newly diagnosed MDS and CCA revealed a large spectrum of nonrandom genomic changes related to the advanced stages of MDS. Chromosome shattering, probably resulting from chromothripsis, was found in 47% of patients. Deleted chromosome 5 was unstable and often involved in different types of cryptic unbalanced rearrangements. No true monosomy 5 was observed. Patients with CCA involving deleted chromosome 5 had an extremely poor prognosis (median overall survival, 2 months).