Practical Recommendations for Hypomethylating Agent Therapy of Patients With Myelodysplastic Syndromes

Epigenetic silencing of E-cadherin gene induced by lncRNA MALAT-1 in acute myeloid leukaemia

Background

Epigenetic abnormalities in acute myeloid leukaemia provide us with a target for novel therapeutic strategies. The aim of the study was to verify the epigenetic regulatory mechanism of E‐cadherin gene silencing induced by long non‐coding RNA MALAT‐1 in AML.

Methods

Expression of MALAT‐1, E‐cadherin, EZH2, SUZ12 and EED genes in AML patients was detected by RT‐qPCR. After MALAT‐1 silencing in AML cell lines, levels of the E‐cadherin, EZH2, SUZ12, EED, DNMT1, DNMT3A and DNMT3B genes and encoded proteins were detected by RT‐qPCR and Western blotting. The level of CpG island methylation and trimethylation modification of histone H3K27 in the promoter region of E‐cadherin was detected by pyrosequencing and ChIP‐qPCR. RIP‐qPCR was used to detect the interaction between MALAT‐1 and proteins.

Results

MALAT‐1, EZH2 and EED gene expression was markedly increased in AML patients with E‐cadherin down‐regulation. A positive correlation between EZH2 or SUZ12 and MALAT‐1 expression was observed. After MALAT‐1 silencing, the expression of E‐cadherin was up‐regulated, whereas the expression of EZH2, SUZ12, DNMT1, DNMT3A and DNMT3B was down‐regulated. Results of Western blotting were consistent with those of RT‐qPCR. Methylation levels of E‐cadherin in AML patients were higher than that in normal controls, which appeared to increase with age. Methylation of the CpG island and H3K27 trimethylation of E‐cadherin were decreased after MALAT‐1 silencing. RIP‐qPCR suggested that MALAT‐1 might be enriched by EZH2 and SUZ12.

Conclusion

Our findings verified that MALAT‐1 might lead to the transcriptional silencing of E‐cadherin gene through the trimethylation of H3K27 mediated by recruiting EZH2 and SUZ12.

Successful Treatment of Myeloid Sarcoma in an Elderly Patient with Myelodysplastic Syndrome with Reduced-Dose Azacitidine

Myeloid sarcoma (MS), which involves extramedullary lesions, is classified as a unique subtype of acute myeloid leukemia (AML). At present, no standard treatments for MS have been established. The patient was an 89-year-old man with myelodysplastic syndrome-excess blast-2 (MDS-EB-2) with a 2-year history of intermittent treatment with azacitidine (AZA) during a 4-year history of MDS. He developed painful cutaneous tumors 8 months after the second discontinuation of AZA. They were refractory for antibiotics and topical tacrolimus hydrate. A tumor biopsy was performed, and the histological findings of the tumor lesion showed a proliferation of tumor cells that were positive for myeloperoxidase and CD68 and negative for CD4 and CD123. The patient was diagnosed with MDS-associated MS. MDS-EB-2 quickly progressed to AML with the appearance of peripheral blood blasts and 25% bone marrow blasts. Monotherapy with reduced-dose AZA (37.5 mg/m² for 7 days, every 4–6 weeks) was restarted, and the MS quickly disappeared. The patient's MS was successfully treated with 16 cycles of AZA treatment over a 22-month period. There have been 10 reported cases in which MS was successfully treated with AZA. Among the 10 cases, the patient in the present case was the oldest. Treatment with reduced-dose AZA should be considered as a therapeutic option for MS in elderly patients with MDS, especially patients who are ineligible for intensive chemotherapy.

Current therapy of myelodysplastic syndromes

After being a neglected and poorly-understood disorder for many years, there has been a recent explosion of data regarding the complex pathogenesis of myelodysplastic syndromes (MDS). On the therapeutic front, the approval of azacitidine, decitabine, and lenalidomide in the last decade was a major breakthrough. Nonetheless, the responses to these agents are limited and most patients progress within 2 years. Allogeneic stem cell transplantation remains the only potentially curative therapy, but it is associated with significant toxicity and limited efficacy. Lack or loss of response after standard therapies is associated with dismal outcomes. Many unanswered questions remain regarding the optimal use of current therapies including patient selection, response prediction, therapy sequencing and combinations, and management of resistance. It is hoped that the improved understanding of the underpinnings of the complex mechanisms of pathogenesis will be translated into novel therapeutic approaches and better prognostic/predictive tools that would facilitate accurate risk-adaptive therapy.

Comparison of 7-day azacitidine and 5-day decitabine for treating myelodysplastic syndrome

Two DNA methyltransferase inhibitors, azacitidine and decitabine, are currently approved for the treatment of myelodysplastic syndrome (MDS). Choosing between these drugs is an important practical issue. In this retrospective study, patients receiving AZA-7d (azacitidine 75 mg/m2 subcutaneously × 7 days, n = 75) or DEC-5d (decitabine 20 mg/m2 intravenously × 5 days, n = 74) were compared. The rates of hematologic response (complete response [CR]/partial response [PR]/marrow CR) were 12.0 % (AZA-7d) vs. 29.7 % (DEC-5d) (P = 0.008), and the overall response rates (CR/PR/marrow CR/hematologic improvement) were 52.0 % (AZA-7d) vs. 63.5 % (DEC-5d) (P = 0.155). Grade 3 or higher neutropenia occurred more frequently with DEC-5d (79.6 %) than with AZA-7d (72.2 %) (P = 0.040). Overall survival probabilities at 2 years were 42.1 % (AZA-7d) vs. 42.2 % (DEC-5d) (P = 0.944). Subgroup analysis revealed that AZA-7d associated with higher survival rates than DEC-5d in patients whose MDS duration exceeded 1 year or who had poor performance status. In conclusion, both AZA-7d and DEC-5d regimens were effective in treating patients with MDS. However, the two regimens differed in terms of clinical responses and toxicities. One hypomethylating regimen may be superior to the other regimen in particular subgroups.

Can hypomethylating agents provide a platform for curative therapy in myelodysplastic syndromes?

The hypomethylating agents (HMAs) azacitidine and decitabine have changed the treatment landscape of myelodysplastic syndromes (MDS) since their approval by the United States Food and Drug Administration (US FDA) in 2004 and 2006, respectively. However, neither agent is able to cure patients with MDS, and when patients fail to respond to treatment with these agents, their prognosis is poor. For this reason, investigators are currently testing combination regimens with an HMA as a backbone and altering the dose, schedule, and method of delivery of HMAs. Additionally, more than 30 new molecules are currently being tested in interventional studies for which patients with MDS are eligible to enroll. These efforts may further improve outcomes for patients with MDS. For the time being, allogeneic stem cell transplantation (ASCT) remains patients' only real opportunity for cure and should be performed whenever possible in patients with higher-risk disease.

Efficacy of hypomethylating agents in therapy-related myelodysplastic syndromes

We retrospectively assessed morphologic and cytogenetic responses to 5-azacytidine and decitabine in a cohort of 42 adult therapy-related myelodysplastic syndromes (tMDS) patients treated at Memorial Sloan-Kettering Cancer Center and in 2 industry-sponsored decitabine trials (D0007 and DACO-020). The overall response rate (complete remission+marrow CR+hematologic improvement) was 38%, including 6 patients with complete remission (14%), 6 with marrow CR with or without hematologic improvement (14%), and 4 with hematologic improvement alone (10%). We conclude that DNA methyltransferase inhibitors showed activity in tMDS that is roughly comparable to that seen in de novo MDS.

Pattern of hypomethylating agents use among elderly patients with myelodysplastic syndromes

Little is known about how hypomethylating agents (HMAs) have been adopted into the treatment of myelodysplastic syndromes (MDS). We conducted a population-based study to assess the use of HMAs among 4416 MDS patients (age≥66 years) who were diagnosed during 2001-2005 and followed up through the end of 2007. Multivariate logistic regression models were utilized to evaluate the role of various patient characteristics. 475 (10.8%) patients had received HMAs by 2007, with the proportion increasing over time. Patients who were white (odds ratio (OR)=0.66, 95% confidence interval (CI): 0.46-0.95), male (OR=1.47, 95% CI: 1.19-1.82), young (Ptrend<0.01), more recently diagnosed (OR=1.90, 95% CI: 1.54-2.34), had fewer comorbidities (Ptrend<0.01), or had a history of other cancer (OR=1.28, 95% CI: 1.00-1.63) were more likely to receive HMAs. Compared with patients with refractory anemia, those diagnosed with refractory anemia with excess blasts or refractory cytopenia with multilineage dysplasia had a higher chance to be treated with HMAs (OR=3.52 and 2.32, respectively). Relatively few MDS patients were treated with HMAs during the introduction period of these agents, and multiple patient characteristics such as sex, comorbidities, and MDS subtype influence the likelihood a patient receives HMAs.

New treatments for myelodysplastic syndromes

In the last decade, significant advances have been made in the treatment of patients with Myelodysplastic Syndromes (MDS). Although best supportive care continues to have an important role in the management of MDS, to date the therapeutic approach is diversified according to the IPSS risk group, karyotype, patient's age, comorbidities, and compliance. Hematopoietic growth factors play a major role in lower risk MDS patients, and include high dose erithropoiesis stimulating agents and thrombopoietic receptor agonists. Standard supportive care should also include iron chelating therapy to reduce organ damage related to iron overload in transfusion-dependent patients. Biologic therapies have been introduced in MDS, as lenalidomide, which has been shown to induce transfusion independence in most lower risk MDS patients with del5q. Hypomethylating agents have shown efficacy in INT-2/high risk MDS patients, reducing the risk of leukemic transformation and increasing survival. Other agents under development for the treatment of MDS include histone deacetylase inhibitors, farnesyltransferase inhibitors, clofarabine and ezatiostat.

How much? How frequent? How long? A clinical guide to new therapies in myelodysplastic syndromes

Advances in the treatment of myelodysplastic syndromes (MDSs) over the last decade have given patients and their hematologists a multitude of treatment options. Therapeutic options now exist that reduce disease-related symptoms, improve quality of life, and alter the natural history of the disease. Three drugs are now specifically Food and Drug Administration-approved for treatment of MDS: (1) azacitidine, (2) decitabine, and (3) lenalidomide. Clinical results with each of these agents, plus results with immunosuppressive therapy, are reviewed to guide clinical decision making. Although each therapy has made a substantial impact in improving the care of patients with MDS, unfortunately MDS treatment in 2010 ultimately fails in most patients, but these therapies provide a foundation on which we can build to further improve outcomes.