Multicenter, phase II study of decitabine for the first-line treatment of older patients with acute myeloid leukemia

A multicenter, retrospective analysis of elderly patients with acute myeloid leukemia who were treated with decitabine

Decitabine is widely accepted as the treatment options for elderly acute myeloid leukemia (AML) patients. However, the efficacy has yet been assessed in Asian population. We retrospectively analyzed the outcomes of 80 Korean elderly AML patients who were treated with decitabine. The median age was 74 years (range, 64 to 86 years) and 6 (7.5%), 48 (60.0%), and 25 (31.3%) patients were categorized to favorable, intermediate, and poor risk group, respectively. The median OS was 10.2 months (95% CI 5.0–15.4). Given that decitabine treatment demonstrated improved clinical outcomes, it could be considered as one of the first-line treatment for Korean elderly AML patients.

How and when to decide between epigenetic therapy and chemotherapy in patients with AML

Remission induction with chemotherapy has long been the frontline treatment of acute myeloid leukemia (AML). However, intensive therapy is limited in frail patients by its associated toxicity and higher rates of failure or relapse in patients with chemoresistant disease, such as secondary AML or poor-risk cytogenetics. Frailty and chemoresistance are more frequent in older adults with AML. In recent years, epigenetic therapies with the hypomethylating agents decitabine and azacitidine have been thoroughly explored in AML. The results of two pivotal studies carried out with these agents in older adults with newly diagnosed AML have challenged the role of intensive chemotherapy as the frontline treatment option in this high-risk population. Here, we review the results of treatment with intensive chemotherapy and hypomethylating agents in older patients with AML; discuss the patient- and disease-specific criteria to integrate into treatment decision making; and also, highlight the methodological limitations of cross-study comparison in this population.

Patterns of infectious complications in acute myeloid leukemia and myelodysplastic syndromes patients treated with 10-day decitabine regimen

Decitabine has been explored as a reduced-intensity therapy for older or unfit patients with acute myeloid leukemia (AML). To better understand the risk of infections during decitabine treatment, we retrospectively examined the culture results from each infection-related serious adverse event that occurred among 85 AML and myelodysplastic syndromes (MDS) patients treated in a prospective clinical study using 10-day cycles of decitabine at Washington University School of Medicine. Culture results were available for 163 infection-related complications that occurred in 70 patients: 90 (55.2%) events were culture-negative, 32 (19.6%) were gram-positive bacteria, 20 (12.3%) were gram-negative bacteria, 12 (7.4%) were mixed, 6 (3.7%) were viral, 2 (1.2%) were fungal, and 1 (0.6%) was mycobacterial. Infection-related mortality occurred in 3/24 (13%) of gram-negative events, and 0/51 gram-positive events. On average, nearly one third of patients experienced an infection-related complication with each cycle, and the incidence did not decrease during later cycles. In summary, in patients receiving 10-day decitabine, infectious complications are common and may occur during any cycle of therapy. Although febrile events are commonly culture-negative, gram-positive infections are the most frequent source of culture-positive infections, but gram-negative infections represent a significant risk of mortality in AML and MDS patients treated with decitabine.

DNA-hypomethylating agents as epigenetic therapy before and after allogeneic hematopoietic stem cell transplantation in myelodysplastic syndromes and juvenile myelomonocytic leukemia

Myelodysplastic syndrome (MDS) is a clonal bone marrow disorder, typically of older adults, which is characterized by ineffective hematopoiesis, peripheral blood cytopenias and risk of progression to acute myeloid leukemia. Juvenile myelomonocytic leukemia (JMML) is an aggressive myeloproliferative neoplasm occurring in young children. The common denominator of these malignant myeloid disorders is the limited benefit of conventional chemotherapy and a particular responsiveness to epigenetic therapy with the DNA-hypomethylating agents 5-azacytidine (azacitidine) or decitabine. However, hypomethylating therapy does not eradicate the malignant clone in MDS or JMML and allogeneic hematopoietic stem cell transplantation (HSCT) remains the only curative treatment option. An emerging concept with intriguing potential is the combination of hypomethylating therapy and HSCT. Possible advantages include disease control with good tolerability during donor search and HSCT preparation, improved antitumoral alloimmunity, and reduced risk of relapse even with non-myeloablative regimens. Herein we review the current role of pre- and post-transplant therapy with hypomethylating agents in MDS and JMML.

Low-dose lenalidomide plus cytarabine in very elderly, unfit acute myeloid leukemia patients: Final result of a phase II study

Outcome for elderly patients with acute myeloid leukemia (AML) is extremely poor. Intensive induction chemotherapy is often unsuitable. Sixty-six newly diagnosed AML patients (median age: 76years), ineligible for standard therapy, were consecutively treated with low-dose lenalidomide (10mg/day orally, days 1-21) plus 10mg/m2 low-dose cytarabine, subcutaneously, twice a day (days 1-15) every six weeks, up to 6 cycles. Complete remission (CR) rate was 36.3% according to intention-to-treat. Responding patients had a longer median overall survival than non-responders (517 vs. 70days, P<0.001). The achievement of CR was not predicted by bone marrow blast count, cytogenetics, molecular markers, prior MDS, white blood cell count. Conversely, by studying the global gene expression profile, we identified a molecular signature, including 309 genes associated with clinical response (CR versus no CR). Based on the expression of a minimal set of 16 genes, we developed an algorithm to predict treatment response, that was successfully validated by showing an overall accuracy of 88%. We met the primary endpoint of the study, by beating the estimated successful CR rate (P1) fixed at 30%. Moreover, CR induced by this 2-drug combo was efficiently predicted by genetic profiling, identifying a biomarker that warrants validation in independent series.

Epigenetic Combination Therapy for Children With Secondary Myelodysplastic Syndrome (MDS)/Acute Myeloid Leukemia (AML) and Concurrent Solid Tumor Relapse

Secondary myelodysplastic syndrome (MDS)/acute myeloid leukemia (AML) is a rare but devastating complication of solid tumor treatment involving high-dose topoisomerase II inhibitor and alkylator chemotherapy. For relapsed or elderly MDS and AML patients ineligible for hematopoietic stem cell transplantation, epigenetic therapies, including DNA methyltransferase inhibitors and histone deacetylase inhibitors, have been utilized as palliative therapy, offering a well-tolerated approach to disease stabilization, prolonged survival, and quality of life. Literature on the use of epigenetic therapies for both primary and relapsed disease is scarce in the pediatric population. Here, we report 2 pediatric patients with secondary AML and MDS, respectively, due to prior therapy for metastatic solid tumors. Both patients were ineligible for hematopoietic stem cell transplantation due to concurrent solid tumor relapse, but were treated with the epigenetic combination therapy, decitabine and vorinostat, and achieved stabilization of marrow disease, outpatient palliation, and family-reported reasonable quality of life.

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.

Molecular targeting in acute myeloid leukemia

Acute myeloid leukemia (AML) is a heterogenous disease associated with distinct genetic and molecular abnormalities. Somatic mutations result in dysregulation of intracellular signaling pathways, epigenetics, and apoptosis of the leukemia cells. Understanding the basis for the dysregulated processes provides the platform for the design of novel targeted therapy for AML patients. The effort to devise new targeted therapy has been helped by recent advances in methods for high-throughput genomic screening and the availability of computer-assisted techniques for the design of novel agents that are predicted to specifically inhibit the mutant molecules involved in these intracellular events. In this review, we will provide the scientific basis for targeting the dysregulated molecular mechanisms and discuss the agents currently being investigated, alone or in combination with chemotherapy, for treating patients with AML. Successes in molecular targeting will ultimately change the treatment paradigm for the disease.

Vosaroxin in combination with decitabine in newly diagnosed older patients with acute myeloid leukemia or high-risk myelodysplastic syndrome

Vosaroxin is an anti-cancer quinolone-derived DNA topoisomerase II inhibitor. We investigated vosaroxin with decitabine in patients ≥60 years of age with newly diagnosed acute myeloid leukemia (n=58) or myelodysplastic syndrome (≥10% blasts) (n=7) in a phase II non-randomized trial. The initial 22 patients received vosaroxin 90 mg/m² on days 1 and 4 with decitabine 20 mg/m² on days 1–5 every 4–6 weeks for up to seven cycles. Due to a high incidence of mucositis the subsequent 43 patients were given vosaroxin 70 mg/m² on days 1 and 4. These 65 patients, with a median age of 69 years (range, 60–78), some of whom with secondary leukemia (22%), adverse karyotype (35%), or TP53 mutation (20%), are evaluable. The overall response rate was 74% including complete remission in 31 (48%), complete remission with incomplete platelet recovery in 11 (17%), and complete remission with incomplete count recovery in six (9%). The median number of cycles to response was one (range, 1–4). Grade 3/4 mucositis was noted in 17% of all patients. The 70 mg/m² induction dose of vosaroxin was associated with similar rates of overall response (74% versus 73%) and complete remission (51% versus 41%, P=0.44), reduced incidence of mucositis (30% versus 59%, P=0.02), reduced 8-week mortality (9% versus 23%; P=0.14), and improved median overall survival (14.6 months versus 5.5 months, P=0.007). Minimal residual disease-negative status by multiparametric flow-cytometry at response (± 3 months) was achieved in 21 of 39 (54%) evaluable responders and was associated with better median overall survival (34.0 months versus 8.3 months, P=0.023). In conclusion, the combination of vosaroxin with decitabine is effective and well tolerated at a dose of 70 mg/m² and warrants randomized prospective evaluation. ClinicalTrials.gov: NCT01893320

The emergence of acid ceramidase as a therapeutic target for acute myeloid leukemia

INTRODUCTION

Acute myeloid leukemia (AML) is the most common adult leukemia. Only a fraction of AML patients will survive with existing chemotherapy regimens. Hence, there is an urgent and unmet need to identify novel targets and develop better therapeutics in AML. In the past decade, the field of sphingolipid metabolism has emerged into the forefront of cancer biology due to its importance in cancer cell proliferation and survival. In particular, acid ceramidase (AC) has emerged as a promising therapeutic target due to its role in neutralizing the pro-death effects of ceramide. Areas covered: This review highlights key information about AML biology as well as current knowledge on dysregulated sphingolipid metabolism in cancer and AML. We describe AC function and dysregulation in cancer, followed by a review of studies that report elevated AC in AML and compounds known to inhibit the enzyme. Expert opinion: AML has a great need for new drug targets and better therapeutic agents. The finding of elevated AC in AML supports the concept that this enzyme represents a novel and realistic therapeutic target for this common leukemia. More effort is needed towards developing better AC inhibitors for clinical use and combination treatment with existing AML therapies.

Successful Management of Decitabine prior to Full-Dose Idarubicin and Cytarabine in the Treatment of Refractory/Recurrent Acute Myeloid Leukemia

AIMS

To investigate the safety and efficacy of the triple therapy of decitabine, idarubicin, and cytarabine in the treatment of refractory or recurrent acute myeloid leukemia (R/R AML).

METHODS

We conducted a single-center retrospective study in which decitabine treatment was administered prior to full-dose idarubicin and cytarabine (D-IA) for 21 R/R AML patients.

RESULTS

After 1 cycle of D-IA, 10/21 (47.6%) patients experienced a complete remission (CR) and 2/21 (9.5%) showed a partial response. There was a 1-month response rate (RR) in 12/21 patients (57.14%); these patients achieved CR after 2 cycles of D-IA. Five of these 12 (40%) patients then received sequential allogeneic stem cell transplantation. At the last follow-up date, 9/21 (42.8%) patients had survived, and 7/21 (33.3%) were in continuous CR. Hematological toxicity and infections were the most prominent toxicities of this regimen. Other toxicities included nausea, vomiting, bleeding, and liver enzyme abnormalities. No mortalities were recorded due to treatment-related toxicity during remission.

CONCLUSIONS

The combination was well tolerated, and the RR was encouraging. Our study suggests that D-IA may offer a novel and potentially effective treatment regimen for R/R AML patients.

Efficacy of single-agent decitabine in relapsed and refractory acute myeloid leukemia

Improving therapy for relapsed/refractory AML remains a challenge. We performed a retrospective analysis of outcomes following decitabine treatment in 34 patients with relapsed/refractory AML (median age, 62; median Charlson comorbidity score, 6). Decitabine, 20 mg/m² daily, was given in 5- (25%) or 10-day (75%) cycles. Overall response rate (OR) was 30% with 21% complete remission and 9% partial remission rate. Patients with therapy-related myeloid neoplasm (t-MN) and secondary AML had a significantly higher OR compared to those with de novo AML (70 vs. 30%; p = .02). Median overall survival of all patients was 8.5 months. Median survival in patients with t-MN or secondary AML was 12.4 months compared to 8 months in those with de novo AML (p = .20). Fifteen (44%) patients proceeded to hematopoietic stem cell transplant. These data support using 10-day treatment cycles of decitabine in patients with relapsed/refractory AML, particularly for those with secondary or therapy-related AML.

Inhibition of DNA and Histone Methylation by 5-Aza-2'-Deoxycytidine (Decitabine) and 3-Deazaneplanocin-A on Antineoplastic Action and Gene Expression in Myeloid Leukemic Cells

Epigenetic alterations play an important role in the development of acute myeloid leukemia (AML) by silencing of genes that suppress leukemogenesis and differentiation. One of the key epigenetic changes in AML is gene silencing by DNA methylation. The importance of this alteration is illustrated by the induction of remissions in AML by 5-aza-2′-deoxycytidine (5-AZA-CdR, decitabine), a potent inhibitor of DNA methylation. However, most patients induced into remission by 5-AZA-CdR will relapse, suggesting that a second agent should be sought to increase the efficacy of this epigenetic therapy. An interesting candidate for this purpose is 3-deazaneplanocin A (DZNep). This analog inhibits EZH2, a histone methyltransferase that trimethylates lysine 27 histone H3 (H3K27me3), a marker for gene silencing. This second epigenetic silencing mechanism also plays an important role in leukemogenesis as shown in preclinical studies where DZNep exhibits potent inhibition of colony formation by AML cells. We reported previously that 5-AZA-CdR in combination with DZNep exhibits a synergistic antineoplastic action against human HL-60 AML cells and the synergistic activation of several tumor suppressor genes. In this report, we showed that this combination also induced a synergistic activation of apoptosis in HL-60 cells. The synergistic antineoplastic action of 5-AZA-CdR plus DZNep was also observed on a second human myeloid leukemia cell line, AML-3. In addition, 5-AZA-CdR in combination with the specific inhibitors of EZH2, GSK-126, or GSK-343, also exhibited a synergistic antineoplastic action on both HL-60 and AML-3. The combined action of 5-AZA-CdR and DZNep on global gene expression in HL-60 cells was investigated in greater depth using RNA sequencing analysis. We observed that this combination of epigenetic agents exhibited a synergistic activation of hundreds of genes. The synergistic activation of so many genes that suppress malignancy by 5-AZA-CdR plus DZNep suggests that epigenetic gene silencing by DNA and histone methylation plays a major role in leukemogenesis. Targeting DNA and histone methylation is a promising approach that merits clinical investigation for the treatment of AML.

[Expression of Septin2 in Hodgkin lymphoma cell line L428 and its role in promoting H/RS cells' redifferentiation to B lymphocytes]

Objective: To explore the role of GTP binding protein 2 (Septin2) in the differentiation of Hodgkin's Lymphoma H/RS cells (Hodgkin/Reed-Sternberg) to B lymphocytes. Methods: The expressions of Septin2 mRNA and protein in Hodgkin's Lymphoma cell line L428 which CD99 was overexpressed were detected by RT-qPCR and Western blot,confocal laser microscopy and immunocytochemistry (ICC) . RT-qPCR and Western blot were used to assay the expression of Septin2 after Septin2-siRNA transfected into L428 cells, and confocal laser microscopy, CCK8 assay and flow cytometry were used to analyze the changes of F-actin cytoskeleton,cell proliferation ability and immunophenotype. Results: The low expressions of Septin2 mRNA and protein were detected in L428 cell line after overexpresion of CD99 (0.329±0.019 vs 1.000, P=0.001) and Septin2 siRNA transfection (0.276±0.025 vs 1.000, P=0.000) compared to controls. Compared to vector group, Septin2 siRNA transfection could lead to decrease of cell size, decline of proliferation activity (F=204.927, P<0.001) and reconstruction of F-actin cytoskeleton, and the expression of specific antigen markers CD30 and CD15 of H/RS cell decreased, B cell antigen marker CD19 as well as germinal center marker CD10 and early plasma cell marker CD38 were up-regulated. Conclusion: Septin2 interference promotes H/RS cells' redifferentiation to B lymphocytes.

Intensive chemotherapy in patients aged 70 years or older newly diagnosed with acute myeloid leukemia

Acute myeloid leukemia (AML) represents a major therapeutic challenge in the elderly. Because of the high treatment-related mortality and poor overall outcomes of remission induction therapy, many older patients are not considered candidates for intensive chemotherapy. The current study evaluated prognostic factors for achievement of complete remission (CR) in newly diagnosed elderly AML patients who were treated with initial intensive chemotherapy. The study included 62 newly diagnosed AML patients ≥70 years who were treated with intensive chemotherapy. The overall response rate (CR and CRp) was 56%. Patients with favorable or intermediate cytogenetics (p = 0.0036) as well as those with primary AML (p = 0.0212) had a higher response rate. The median overall survival for all patients was 6.85 months (95% CI 3.7–13.5 months). The median overall survival for patients achieving remission after intensive induction chemotherapy was significantly higher than those who did not respond to therapy (20.4 months vs. 3.5 months, p < 0.001). The all-cause 4-week mortality rate was 11%, and the all-cause 8-week mortality rate was 17.7%. A subgroup of elderly patients may benefit more from initial intensive induction chemotherapy, specifically those patients with performance status able to tolerate induction chemotherapy and favorable cytogenetic status. However, despite high rates of initial CR, relapse rates are still high, suggesting that alternative strategies of postremission therapy are warranted.

Evaluating the impact of genetic and epigenetic aberrations on survival and response in acute myeloid leukemia patients receiving epigenetic therapy

Treatment with hypomethylating agents such as decitabine, which results in overall response rates of up to 50%, has become standard of care in older patients with acute myeloid leukemia (AML) who are not candidates for intensive chemotherapy. However, there still exists a lack of prognostic and predictive molecular biomarkers that enable selection of patients who are likely to benefit from epigenetic therapy. Here, we investigated distinct genetic (FLT3-ITD, NPM1, DNMT3A) and epigenetic (estrogen receptor alpha (ERα), C/EBPα, and OLIG2) aberrations in 87 AML patients from the recently published phase II decitabine trial (AML00331) to identify potential biomarkers for patients receiving hypomethylating therapy. While FLT3-ITD and NPM1 mutational status were not associated with survival or response to therapy, patients harboring DNMT3A R882 mutations showed a non-significant association towards shorter overall survival (hazard ratio (HR) 2.15, 95% confidence interval (CI) 0.91-5.12, p = 0.08). Promoter DNA methylation analyses using pyrosequencing also revealed a non-significant association towards shorter overall survival of patients with higher levels of methylation of ERα (HR 1.50, CI 0.97-2.32, p = 0.07) and OLIG2 CpG4 (HR 1.52, CI 0.96-2.41, p = 0.08), while DNA methylation of C/EBPα showed no association with outcome. Importantly, in multivariate analyses adjusted for clinical baseline parameters, the impact of ERα and OLIG2 CpG4 methylation was conserved (HR 1.76, CI 1.01-3.06, p = 0.05 and HR 1.67, CI 0.91-3.08, p = 0.10, respectively). In contrast, none of the investigated genetic and epigenetic markers was associated with response to treatment. Additional to the previously reported adverse prognostic clinical parameters such as patients' age, reduced performance status, and elevated lactate dehydrogenase levels, DNMT3A R882 mutation status, as well as ERα and OLIG2 CpG4 DNA methylation status, may prove to be molecular markers in older AML patients prior to hypomethylating therapy.

Decitabine as a First-Line Treatment for Older Adults Newly Diagnosed with Acute Myeloid Leukemia

PURPOSE

Decitabine, a DNA hypomethylating agent, was recently approved for use in Korea for older adults with acute myeloid leukemia (AML) who are not candidates for standard chemotherapy. This study aimed to evaluate the role of decitabine as a first-line treatment for older adults with AML.

MATERIALS AND METHODS

Twenty-four patients with AML who received at least one course of decitabine (20 mg/m²/d intravenously for 5 days every 4 weeks) as a first-line therapy at Severance Hospital were evaluated retrospectively.

RESULTS

The median age of the patients was 73.5 years. The longest follow-up duration was 502 days. A total of 113 cycles of treatment were given to 24 patients, and the median number of cycles was four (range, 1-14). Thirteen patients dropped out because of death, no or loss of response, patient refusal, or transfer to another hospital. Twenty-one (87.5%) and 12 (50%) patients completed the second and fourth cycles, respectively, and responses to treatment were evaluated in 17. A complete response (CR) or CR with incomplete blood-count recovery was achieved in six (35.3%) patients, and the estimated median overall survival was 502 days. Ten patients developed grade >2 hematologic or non-hematologic toxicities. In univariate analysis, bone marrow blasts, lactate dehydrogenase, serum ferritin level, and bone marrow iron were significantly associated with response to decitabine.

CONCLUSION

Five-day decitabine treatment showed acceptable efficacy in older patients with AML who are unfit for conventional chemotherapy, with a CR rate 35.3% and about a median overall survival of 18 months.

Older Patients With Acute Myeloid Leukemia: Treatment Challenges and Future Directions

BACKGROUND

Even though acute myeloid leukemia (AML) occurs most commonly in adults ≥60 years, the treatment of AML in older patients remains a significant challenge.

METHODS

We reviewed the current literature regarding patient assessment tools, treatment options, and current therapies in clinical trial for patients with AML who are ≥60 years.

RESULTS

Our approach to the older patient with AML is evolving with better understanding of the unique disease epidemiology in this population and the development of tools to assess individual patient functional status, including grading systems for comorbidities, geriatric assessment tools, and measurements of frailty. Almost all older patients will benefit from therapy, whether intensive curative therapy, such as allogeneic stem cell transplant that should be considered whenever possible, or low-intensity therapy that should be offered with concurrent palliative care at diagnosis to improve patient survival and quality of life. To achieve the improved survival demonstrated in younger adults, older patients should also be considered for clinical trial enrollment as more studies are being designed to specifically target this unique patient population.

CONCLUSION

Older patients with AML are candidates for and benefit from the entire spectrum of AML therapy, including intense chemotherapy, allogeneic stem cell transplant, and clinical trial participation after thorough patient assessment. Older patients with AML would benefit from increased clinical trial enrollment and early inclusion of palliative medicine.

TP53 and Decitabine in Acute Myeloid Leukemia and Myelodysplastic Syndromes

BACKGROUND

The molecular determinants of clinical responses to decitabine therapy in patients with acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS) are unclear.

METHODS

We enrolled 84 adult patients with AML or MDS in a single-institution trial of decitabine to identify somatic mutations and their relationships to clinical responses. Decitabine was administered at a dose of 20 mg per square meter of body-surface area per day for 10 consecutive days in monthly cycles. We performed enhanced exome or gene-panel sequencing in 67 of these patients and serial sequencing at multiple time points to evaluate patterns of mutation clearance in 54 patients. An extension cohort included 32 additional patients who received decitabine in different protocols.

RESULTS

Of the 116 patients, 53 (46%) had bone marrow blast clearance (<5% blasts). Response rates were higher among patients with an unfavorable-risk cytogenetic profile than among patients with an intermediate-risk or favorable-risk cytogenetic profile (29 of 43 patients [67%] vs. 24 of 71 patients [34%], P<0.001) and among patients with TP53 mutations than among patients with wild-type TP53 (21 of 21 [100%] vs. 32 of 78 [41%], P<0.001). Previous studies have consistently shown that patients with an unfavorable-risk cytogenetic profile and TP53 mutations who receive conventional chemotherapy have poor outcomes. However, in this study of 10-day courses of decitabine, neither of these risk factors was associated with a lower rate of overall survival than the rate of survival among study patients with intermediate-risk cytogenetic profiles.

CONCLUSIONS

Patients with AML and MDS who had cytogenetic abnormalities associated with unfavorable risk, TP53 mutations, or both had favorable clinical responses and robust (but incomplete) mutation clearance after receiving serial 10-day courses of decitabine. Although these responses were not durable, they resulted in rates of overall survival that were similar to those among patients with AML who had an intermediate-risk cytogenetic profile and who also received serial 10-day courses of decitabine. (Funded by the National Cancer Institute and others; ClinicalTrials.gov number, NCT01687400 .).

Phase I Study of Epigenetic Priming with Azacitidine Prior to Standard Neoadjuvant Chemotherapy for Patients with Resectable Gastric and Esophageal Adenocarcinoma: Evidence of Tumor Hypomethylation as an Indicator of Major Histopathologic Response

Purpose: Epigenetic silencing of tumor suppressor genes (TSG) is an acquired abnormality observed in cancer and is prototypically linked to DNA methylation. We postulated that pretreatment (priming) with 5-azacitidine would increase the efficacy of chemotherapy by reactivating TSGs. This study was conducted to identify a tolerable dose of 5-azacitidine prior to EOX (epirubicin, oxaliplatin, capecitabine) neoadjuvant chemotherapy in patients with locally advanced esophageal/gastric adenocarcinoma (EGC).Experimental Design: Eligible patients had untreated, locally advanced, resectable EGC, ECOG 0-2, and adequate organ function. 5-Azacitidine (V, 75 mg/m²) was given subcutaneously for 3 (dose level, DL 1) or 5 (DL 2) days prior to each 21-day cycle of EOX (E, 50 mg/m²; O, 130 mg/m²; X, 625 mg/m² twice daily for 21 days). Standard 3+3 methodology guided V dose escalation. DNA methylation at control and biomarker regions was measured by digital droplet, bisulfite qPCR in tumor samples collected at baseline and at resection.Results: All subjects underwent complete resection of residual tumor (R0). Three of the 12 patients (25%) achieved a surgical complete response and 5 had partial responses. The overall response rate was 67%. The most common toxicities were gastrointestinal and hematologic. Hypomethylation of biomarker genes was observed at all dose levels and trended with therapeutic response.Conclusions: Neoadjuvant VEOX was well-tolerated with significant clinical and epigenetic responses, with preliminary evidence that priming with V prior to chemotherapy may augment chemotherapy efficacy. The recommended phase II trial schedule is 5-azacitidine 75 mg/m² for 5 days followed by EOX chemotherapy every 21 days. Clin Cancer Res; 23(11); 2673-80. ©2016 AACR.

Dynamic changes in the clonal structure of MDS and AML in response to epigenetic therapy

Traditional response criteria in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) are based on bone marrow morphology and may not accurately reflect clonal tumor burden in patients treated with non-cytotoxic chemotherapy. We used next-generation sequencing of serial bone marrow samples to monitor MDS and AML tumor burden during treatment with epigenetic therapy (decitabine and panobinostat). Serial bone marrow samples (and skin as a source of normal DNA) from 25 MDS and AML patients were sequenced (exome or 285 gene panel). We observed that responders, including those in complete remission (CR), can have persistent measurable tumor burden (that is, mutations) for at least 1 year without disease progression. Using an ultrasensitive sequencing approach, we detected extremely rare mutations (equivalent to 1 heterozygous mutant cell in 2000 non-mutant cells) months to years before their expansion at disease relapse. While patients can live with persistent clonal hematopoiesis in a CR or stable disease, ultimately we find evidence that expansion of a rare subclone occurs at relapse or progression. Here we demonstrate that sequencing of serial samples provides an alternative measure of tumor burden in MDS or AML patients and augments traditional response criteria that rely on bone marrow blast percentage.

Selecting initial treatment of acute myeloid leukaemia in older adults

More than half of the patients with acute myeloid leukaemia (AML) are older than 60years. The treatment outcomes in this group remain poor with a median overall survival of <1year. Selecting initial treatment for these patients involves an assessment of 'fitness' for induction chemotherapy. This is done based on patient and disease-related characteristics which help to estimate treatment-related mortality and chance of complete remission with induction chemotherapy. If the risk of treatment-related mortality is high and/or the likelihood of a patient achieving a complete remission is low, lower-intensity treatment (low-dose cytarabine, decitabine and azacitidine) should be discussed. As outcomes in both groups of patients remain poor, enrolment into clinical trials of novel agents with varying mechanisms of action should be considered for all older adults with AML. Novel agents in Phase III development include CPX-351, guadecitabine (SGI-110), quizartinib, crenolanib, sapacitabine, vosaroxin and volasertib.

The hypomethylating agent decitabine prior to chemotherapy improves the therapy efficacy in refractory/relapsed acute myeloid leukemia patients

In this study, we investigated the effect of pre-treatment with demethylating agent decitabine on susceptibility to chemotherapeutic drugs in HL60/ADR, Kasumi-1 and primary AML cells. Cytotoxic effect was increased by decitabine through activation of p53 and inhibition of c-Myc, Survivin and Bcl-2. We demonstrated in clinic that combination of decitabine and HAA consisting of harringtonine, aclarubicin and cytarabine was effective and safe to treat patients with refractory, relapsed or high-risk AML. Decitabine prior to HAA regimen improved the first induction complete response rate, and significantly prolonged overall survival and disease-free survival in these patients compared with HAA alone. These findings support clinic protocols based on decitabine prior to chemotherapy to overcome resistance and improve therapeutic efficacy in AML patients.

Maintenance therapy with decitabine in younger adults with acute myeloid leukemia in first remission: a phase 2 Cancer and Leukemia Group B Study (CALGB 10503)

In this prospective phase 2 clinical trial conducted by Cancer and Leukemia Group B (CALGB, now the Alliance), we studied decitabine as maintenance therapy for younger adults with acute myeloid leukemia (AML) who remained in first complete remission (CR1) following intensive induction and consolidation. Given that decitabine is clinically active in AML and with hypomethylating activity distinct from cytotoxic chemotherapy, we hypothesized that one year of maintenance therapy would improve disease-free survival (DFS) for AML patients <60 years who did not receive allogeneic stem cell transplantation (alloHCT) in CR1. After blood count recovery from final consolidation, patients received decitabine at 20mg/m² IV daily for 4–5 days, every 6 weeks for 8 cycles. One-hundred-thirty-four patients received decitabine, 85 (63%) had favorable risk AML. The median number of cycles received was 7 (range, 1–8), and the primary reason for discontinuation was relapse. DFS at 1-year and 3-years was 79% and 54%, respectively. These results are similar to the outcomes in the historical control comprised of similar patients treated on recent CALGB trials. Thus, maintenance with decitabine provided no benefit overall. Standard use of decitabine maintenance in younger AML patients in CR1 is not warranted. This trial was registered at www.clinicaltrials.gov as NCT00416598.

An Evaluation of Treatment Patterns and Outcomes in Elderly Patients Newly Diagnosed With Acute Myeloid Leukemia: A Retrospective Analysis of Electronic Medical Records From US Community Oncology Practices

BACKGROUND

Many elderly patients with acute myeloid leukemia (AML) are considered ineligible for standard intensive induction therapy due to performance status and comorbidities. We analyzed treatment patterns and outcomes among elderly patients newly diagnosed with AML in the US community oncology setting.

METHODS

A retrospective observational study was conducted using patient-level data from a network of US community oncology practices provided by Altos Solutions. Patients aged ≥ 60 years, diagnosed with AML between November 2005 and February 2014, with ≥ 1 recorded visit and ≥ 6 months between diagnosis and data cutoff, were included. Only patients who received active treatment or best supportive care (BSC) per National Comprehensive Cancer Network (NCCN) AML Guidelines were analyzed.

RESULTS

Of 1139 patients meeting the inclusion criteria, 922 (median age 76 years) received NCCN-recommended treatments: standard induction (n = 5), low-intensity therapy (n = 425), BSC with hydroxyurea (HU) (n = 36), or BSC without HU (n = 455). For the low-intensity therapy cohort, median time from diagnosis to treatment initiation was 17 days; median duration of therapy was 5.1 months. Median overall survival (OS) from diagnosis in the low-intensity, BSC with HU, and BSC without HU groups was 12.3, 7.0, and 49.4 months, respectively. Median time to next therapy/death was 10.1 months in patients receiving low-intensity therapy. A higher proportion of patients receiving low-intensity therapy required transfusion or other supportive care versus those receiving BSC.

CONCLUSIONS

As expected, OS in patients receiving low-intensity therapy or BSC with HU is poor for elderly patients with AML. Remarkably, intensive induction strategies are rarely used for older patients in community oncology practice.

How I treat acute myeloid leukemia presenting with preexisting comorbidities

Acute myeloid leukemia (AML) is a devastating disease with an incidence that progressively increases with advancing age. Currently, only ∼40% of younger and 10% of older adults are long-term survivors. If untreated, the overall prognosis of AML remains dismal. Initiation of therapy at diagnosis is usually urgent. Barriers to successful therapy for AML are the attendant toxicities directly related to chemotherapy or those associated with inevitable aplasia. Organ dysfunction often further complicates such toxicities and may even be prohibitive. There are few guidelines to manage such patients and the fear of crossing the medico-legal abyss may dominate. Such clinical scenarios provide particular challenges and require experience for optimal management. Herein, we discuss select examples of common pretreatment comorbidities, including cardiomyopathy, ischemic heart disease; chronic renal failure, with and without dialysis; hepatitis and cirrhosis; chronic pulmonary insufficiency; and cerebral vascular disease. These comorbidities usually render patients ineligible for clinical trials and enormous uncertainty regarding management reigns, often to the point of withholding definitive therapy. The scenarios described herein emphasize that with appropriate subspecialty support, many AML patients with comorbidities can undergo therapy with curative intent and achieve successful long-term outcome.

Targeting epigenetic pathways in acute myeloid leukemia and myelodysplastic syndrome: a systematic review of hypomethylating agents trials

Background

Aberrant DNA methylation has been identified as a key molecular event regulating the pathogenesis of myelodysplastic syndromes (MDS); myeloid neoplasms with an inherent risk of transformation to acute myeloid leukemia (AML). Based on the above findings, DNA hypomethylating agents (HMA) have been widely used to treat AML and MDS, especially in elderly patients and in those who are not eligible for allogeneic stem cell transplantation (SCT). Our goal was to determine if there is any therapeutic advantage of HMA vs. conventional care regimens (CCR) and indirectly compare the efficacy of azacitidine and decitabine in this patient population.

Methods

Eligible studies were limited to randomized controlled trials comparing HMA to CCR in adult patients with AML or MDS.

Results

Overall survival (OS) rate was 33.2 vs. 21.4 % (RR 0.83, 95 % CI 0.71–0.98) and overall response rate (ORR) 23.7 vs. 13.4 % (RR 0.87, 95 % CI 0.81–0.93) for HMA and CCR, respectively. In subgroup analyses, only azacitidine treatment showed OS improvement (RR 0.75, 95 % CI 0.64–0.98) and not decitabine. Cytogenetic risk or bone marrow blast count did not have independent prognostic impact.

Conclusion

Collectively, these results demonstrate that HMA have superior outcomes compared to CCR and suggest that azacitidine in comparison to decitabine, may be more effective.

Electronic supplementary material

The online version of this article (doi:10.1186/s13148-016-0233-2) contains supplementary material, which is available to authorized users.

An open-label, single-arm, phase I/II study of lower-dose decitabine based therapy in patients with advanced hepatocellular carcinoma

Purpose

We conducted this phase I/II clinical trial to determine the safety and efficacy of lower-dose decitabine based therapy in pretreated patients with advanced HCC.

Experimental Design

Patients with advanced HCC were eligible. The administered dose of decitabine was 6 mg/m²/d intravenously on days 1 to 5 of a 28-day cycle. Additional therapies were given based on their disease progression status. The endpoint was to ensure the safety, hepatotoxicity, clinical responses, progression-free survival (PFS) and pharmacodynamics assay of lower-dose decitabine.

Results

Fifteen patients were enrolled. The favorable adverse events and liver function profiles were observed. The most beneficial responses were 1 complete response (CR), 6 stable disease (SD) and 8 progressive disease (PD). MRI liver scans post-treatment indicated a unique and specific characteristic. The immunohistochemistry result from the liver biopsy exhibited noteworthy CTL responses. Median PFS was 4 months (95% CI 1.7, 7), comparing favorably with existing therapeutic options. Expression decrement of DNMT1 and global DNA hypomethylation were observed in PBMCs after lower-dose decitabine treatment.

Conclusion

The lower-dose decitabine based treatment resulted in beneficial clinical response and favorable toxicity profiles in patients with advanced HCC. The prospective evaluations of decitabine administration schemes and tumor tissue-based pharmacodynamics effect are warranted in future trials.

Emerging strategies for the treatment of older patients with acute myeloid leukemia

Acute myeloid leukemia (AML) is the most common acute leukemia in adults, and its incidence increases with age. Clinical outcomes in younger patients have improved over the years but, unfortunately, there is little evidence for an equivalent improvement in outcome for older patients. Approximately 50 % of older patients who are able to receive intensive chemotherapy will achieve a complete remission; however, they face a much higher relapse rate than younger patients, and survival rates for this group are low. Therefore, there is an urgent need to improve outcomes in older patients with AML. In this article, we discuss current treatment paradigms for older patients with AML including the challenges faced when determining which patients are eligible for intensive chemotherapy. We then highlight new treatments in development that may benefit this patient group. Cytotoxic agents, hypomethylating agents, molecularly targeted agents, and cell cycle kinase inhibitors are discussed, with a focus on novel agents that have achieved an advanced stage of development. Overall, the treatment of AML in older patients remains a challenge and, whenever possible, treatment should be offered in the context of clinical trials and should be planned with curative intent.

Outcomes of Allogeneic Stem Cell Transplantation in Elderly Patients with Acute Myeloid Leukemia: A Systematic Review and Meta-analysis

A large number of elderly patients with acute myeloid leukemia (AML) are not offered treatments with curative intent, such as allogeneic stem cell transplantation (SCT), because of fears of toxicity and perceived futility of intensive treatment. Therefore, the outcomes of SCT in elderly AML patients remain poorly defined. We performed a meta-analysis of all previous articles up until September 22, 2015 of SCT in AML patients >60 years. The primary endpoints were relapse-free survival (RFS) and overall survival (OS) at 6 months and at 1, 2, and 3 years. A total of 13 studies (749 patients) were included. The pooled estimates and 95% confidence intervals (CI) for RFS at 6 months, 1 year, 2 years, and 3 years were 62% (95% CI, 54% to 69%), 47% (95% CI, 42% to 53%), 44% (95% CI, 33% to 55%), and 35% (95% CI, 26% to 45%), respectively. The corresponding numbers for OS were 73% (95% CI, 66% to 79%), 58% (95% CI, 50% to 65%), 45% (95% CI, 35% to 54%), and 38% (95% CI, 29% to 48%), respectively. We found no evidence of publication bias in our primary endpoints, with the exception of relapse, where there appeared to be a relative lack of small studies with high relapse rates. Sensitivity analysis did not identify an overtly influential study for our primary endpoints, with 1 exception in 2-year RFS analysis. The present analysis argues against significant publication bias and demonstrates consistency among reports despite differences in patient-, disease-, center-, and transplantation-related characteristics. Our results suggest that reduced-intensity SCT is a viable treatment option for elderly AML patients with a 3-year RFS of 35% for those over the age of 60. These results argue against using age per se as the sole criterion against SCT and would help remove some of the barriers that often preclude curative intent treatment. Correct identification of patients who would benefit from SCT can improve outcomes in this frequently undertreated population.

Molecular and Cellular Mechanisms of Myelodysplastic Syndrome: Implications on Targeted Therapy

Myelodysplastic syndrome (MDS) is a group of heterogeneous clonal hematopoietic stem cell disorders characterized by cytopenia, ineffective hematopoiesis, and progression to secondary acute myeloid leukemia in high-risk cases. Conventional prognostication relies on clinicopathological parameters supplemented by cytogenetic information. However, recent studies have shown that genetic aberrations also have critical impacts on treatment outcome. Moreover, these genetic alterations may themselves be a target for treatment. The mutation landscape in MDS is shaped by gene aberrations involved in DNA methylation (TET2, DNMT3A, IDH1/2), histone modification (ASXL1, EZH2), the RNA splicing machinery (SF3B1, SRSF2, ZRSR2, U2AF1/2), transcription (RUNX1, TP53, BCOR, PHF6, NCOR, CEBPA, GATA2), tyrosine kinase receptor signaling (JAK2, MPL, FLT3, GNAS, KIT), RAS pathways (KRAS, NRAS, CBL, NF1, PTPN11), DNA repair (ATM, BRCC3, DLRE1C, FANCL), and cohesion complexes (STAG2, CTCF, SMC1A, RAD21). A detailed understanding of the pathogenetic mechanisms leading to transformation is critical for designing single-agent or combinatorial approaches in target therapy of MDS.

Secondary Adult Acute Myeloid Leukemia: a Review of Our Evolving Understanding of a Complex Disease Process

OPINION STATEMENT

Secondary AML (s-AML) encompasses AML evolving from myelodysplasia (AML-MDS) and treatment-related AML (t-AML) after exposure to chemotherapy, radiation, or environmental toxins. S-AML has traditionally been considered a devastating disease, affecting a vulnerable population of heavily pretreated, older adults. A limited understanding of disease pathogenesis/heterogeneity and lack of effective treatments have hampered overall improvements in patient outcomes. With the recent understanding that the secondary nature of sAML does not by itself incur a poor prognosis and incorporation of cytogenetics and molecular genetics into patient care and the advancement of treatment, including improved supportive care, novel chemotherapeutics agents, and nonmyeloablative conditioning regimens as part of allogeneic hematopoietic cell transplantation (HCT), modest gains in survival and quality of life are beginning to be seen among patients with s-AML.

Changes in expression of WT1 during induced differentiation of the acute myeloid leukemia cell lines by treatment with 5-aza-2'-deoxycytidine and all-trans retinoic acid

The aim of the present study was to investigate the effect of 5-aza-2'-deoxycytidine (decitabine; DAC) and all-trans retinoic acid (ATRA) on Wilms' tumor 1 (WT1) in acute myeloid leukemia (AML) in vitro. The methylation status of the WT1 promoter was analyzed using methylation-specific polymerase chain reaction (MSP). The expression level of WT1 was detected by reverse transcription-quantitative polymerase chain reaction. The effect of DAC and ATRA on cell differentiation was evaluated by flow cytometry. The WT1 gene was methylated in U937 cells, but unmethylated in SHI-1 and K562 cells; the U937 cells did not express the WT1 gene, but the SHI-1 and K562 cells highly expressed the WT1 gene. DAC and ATRA, alone or in combination, exhibited no effect on the expression level of WT1 in the U937 cells and on the differentiation of the K562 cells. The combined treatment of DAC and ATRA markedly decreased the WT1 expression levels of the SHI-1 and K562 cells, and induced the differentiation of the SHI-1 and U937 cells. In the SHI-1 cells, WT1 expression changed inversely to the dynamic changes of cluster of differentiation 11b-positive rates. In conclusion, the combined treatment of DAC and ATRA has clinical therapeutic potential in acute monocytic leukemia patients with high WT1 expression and a poor response to standard induction chemotherapy.

Novel immunotherapeutic approaches for the treatment of acute leukemia (myeloid and lymphoblastic)

There have been major advances in our understanding of the multiple interactions between malignant cells and the innate and adaptive immune system. While the attention of immunologists has hitherto focused on solid tumors, the specific immunobiology of acute leukemias is now becoming defined. These discoveries have pointed the way to immune interventions building on the established graft-versus-leukemia (GVL) effect from hematopoietic stem-cell transplant (HSCT) and extending immunotherapy beyond HSCT to individuals with acute leukemia with a diversity of immune manipulations early in the course of the leukemia. At present, clinical results are in their infancy. In the coming years larger studies will better define the place of immunotherapy in the management of acute leukemias and lead to treatment approaches that combine conventional chemotherapy, immunotherapy and HSCT to achieve durable cures.

Treatments and costs for recurrent and/or metastatic squamous cell carcinoma of the head and neck in the Netherlands

For patients with recurrent and/or metastatic squamous cell carcinoma of the head and neck (R/M SCCHN), chemotherapy can prolong life and alleviate symptoms. However, expected gains may be small, not necessarily outweighing considerable toxicity and high costs. Treatment choice is to a large extent dependent on preferences of doctors and patients and data on these choices are scarce. The purpose of this study is to obtain real-world information on palliative systemic treatment and costs of R/M SCCHN in the Netherlands. In six Dutch head and neck treatment centers, data were collected on patient and tumor characteristics, treatment patterns, disease progression, survival, adverse events, and resource use for R/M SCCHN, between 2006 and 2013. 125 (14 %) out of 893 R/M SCCHN patients received palliative, non-trial first-line systemic treatment, mainly platinum + 5FU + cetuximab (32 %), other platinum-based combination therapy (13 %), methotrexate monotherapy (27 %) and capecitabine monotherapy (14 %). Median progression-free survival and overall survival were 3.4 and 6.0 months, respectively. 34 (27 %) patients experienced severe adverse events. Mean total hospital costs ranged from € 10,075 (± € 9,891) (methotrexate monotherapy) to € 39,459 (± € 21,149) (platinum + 5FU + cetuximab). Primary cost drivers were hospital stays and anticancer drug treatments. Major health care utilization and costs are involved in systemically treating R/M SCCHN patients with a limited survival.

Are we curing more older adults with acute myeloid leukemia with allogeneic transplantation in CR1?

PURPOSE OF REVIEW

Despite the fact that acute myeloid leukemia (AML) is most common in older adults aged at least 60 years, curative therapy remains elusive in this population. Here we examine the data for predicting which patients are candidates for 'curative therapy', available therapeutic options, and the utilization of reduced intensity allogeneic stem cell transplantation in first remission.

RECENT FINDINGS

Incorporation of geriatric assessment tools to assess patient frailty, in addition to evaluation of comorbid conditions, improves patient selection for intense therapy. The majority of patients eligible for and treated with induction chemotherapy achieve complete remission, and overall survival in the older AML population is superior after allogeneic stem cell transplant. However, population-based studies continue to demonstrate the undertreatment or lack of treatment of older AML patients.

SUMMARY

New patient assessment tools, ability to offer more successful outcomes after induction chemotherapy, and improved survival after allogeneic transplantation has not yet translated to increased 'curative' treatment on a population level of older AML patients. It is critical that the tools and therapies available be put into practice while older patient enrollment in well designed therapeutic clinical trials which include the option of allogeneic transplantation is increased.

Gemtuzumab Ozogamicin Versus Best Supportive Care in Older Patients With Newly Diagnosed Acute Myeloid Leukemia Unsuitable for Intensive Chemotherapy: Results of the Randomized Phase III EORTC-GIMEMA AML-19 Trial

PURPOSE

To compare single-agent gemtuzumab ozogamicin (GO) with best supportive care (BSC) including hydroxyurea as first-line therapy in older patients with acute myeloid leukemia unsuitable for intensive chemotherapy.

PATIENTS AND METHODS

In this trial, patients at least 61 years old were centrally randomized (1:1) to receive either a single induction course of GO (6 mg/m(2) on day 1 and 3 mg/m(2) on day 8) or BSC. Patients who did not progress after GO induction could receive up to eight monthly infusions of the immunoconjugate at 2 mg/m(2). Randomization was stratified by age, WHO performance score, CD33 expression status, and center. The primary end point was overall survival (OS) by intention-to-treat analysis.

RESULTS

A total of 237 patients were randomly assigned (118 to GO and 119 to BSC). The median OS was 4.9 months (95% CI, 4.2 to 6.8 months) in the GO group and 3.6 months (95% CI, 2.6 to 4.2 months) in the BSC group (hazard ratio, 0.69; 95% CI, 0.53 to 0.90; P = .005); the 1-year OS rate was 24.3% with GO and 9.7% with BSC. The OS benefit with GO was consistent across most subgroups, and was especially apparent in patients with high CD33 expression status, in those with favorable/intermediate cytogenetic risk profile, and in women. Overall, complete remission (CR [complete remission] + CRi [CR with incomplete recovery of peripheral blood counts]) occurred in 30 of 111 (27%) GO recipients. The rates of serious adverse events (AEs) were similar in the two groups, and no excess mortality from AEs was observed with GO.

CONCLUSION

First-line monotherapy with low-dose GO, as compared with BSC, significantly improved OS in older patients with acute myeloid leukemia who were ineligible for intensive chemotherapy. No unexpected AEs were identified and toxicity was manageable.

Targeting epigenetic regulations in cancer

Epigenetic regulation of gene expression is a dynamic and reversible process with DNA methylation, histone modifications, and chromatin remodeling. Recently, groundbreaking studies have demonstrated the importance of DNA and chromatin regulatory proteins from different aspects, including stem cell, development, and tumor genesis. Abnormal epigenetic regulation is frequently associated with diseases and drugs targeting DNA methylation and histone acetylation have been approved for cancer therapy. Although the network of epigenetic regulation is more complex than people expect, new potential druggable chromatin-associated proteins are being discovered and tested for clinical application. Here we review the key proteins that mediate epigenetic regulations through DNA methylation, the acetylation and methylation of histones, and the reader proteins that bind to modified histones. We also discuss cancer associations and recent progress of pharmacological development of these proteins.

The combination of FLT3 and DNA methyltransferase inhibition is synergistically cytotoxic to FLT3/ITD acute myeloid leukemia cells

Effective treatment regimens for elderly acute myeloid leukemia (AML) patients harboring internal tandem duplication mutations in the FMS-like tyrosine kinase-3 (FLT3) gene (FLT3/ITD) are lacking and represent a significant unmet need. Recent data on the effects of FLT3 tyrosine kinase inhibitors on FLT3/ITD(+) AML showed promising clinical activity, including in elderly patients. DNA methyltransferase (DNMT) inhibitors such as decitabine (5-aza-2-deoxycytidine, DEC) and 5-azacitidine (AZA) demonstrated clinical benefit in AML, are well tolerated and are associated with minimal increases in FLT3 ligand, which can represent a potential resistance mechanism to FLT3 inhibitors. In addition, both FLT3 and DNMT inhibition are associated with the induction of terminal differentiation of myeloid blasts. Consequently, there is a strong theoretical rationale for combining FLT3 and DNMT inhibition for FLT3/ITD(+) AML. We therefore sought to study the anti-leukemic effects of DEC, AZA and FLT3 inhibitors, either as single agents or in combination, on AML cell lines and primary cells derived from newly diagnosed and relapsed AML patients. Our studies indicate that combined treatment using FLT3 inhibition and hypomethylation confers synergistic anti-leukemic effects, including apoptosis, growth inhibition and differentiation. The simultaneous administration of AZA and FLT3 inhibition appears to be the most efficacious combination in this regard. These drugs may provide a novel therapeutic approach for FLT3/ITD(+) AML, in particular for older patients.