Feasibility of allo-SCT after hypomethylating therapy with decitabine for myelodysplastic syndrome

Efficacy of decitabine combined with allogeneic hematopoietic stem cell transplantation in the treatment of recurrent and refractory acute myeloid leukemia (AML): A systematic review and meta-analysis

BACKGROUND

This analysis aimed to assess the effect of decitabine combined with allogeneic hematopoietic stem cell transplantation (allo-HSCT) in treating recurrent and refractory acute myeloid leukemia.

METHOD

The present analysis was carried out according to the principles of Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline statement. Web of Science, Embase, PubMed, The Cochrane Library, CNKI, VIP, and WanFang Data databases were searched for trials published from their corresponding inception to September 13, 2021. Retrospective research or published randomized controlled trials in Chinese or English were ruled out. The methodological quality of the included studies was assessed using the Physiotherapy Evidence Database scale. Mean differences with 95% confidence intervals were used to analyze continuous data. The I2 test was used to determine heterogeneity, and the meta-analysis was conducted using Revman 5.4.

RESULTS

Eight studies including 795 participants in total were identified. Decitabine and allo-HSCT showed significant reductions in recurrence after transplantation (odds ratio [OR] = 0.29, 95% confidence interval [CI] (0.17, 0.50), P < .00001), leukemia-free survival (OR = 2.17, 95% CI (1.47, 3.21), P < .0001), graft related death (OR = 0.50, 95% CI (0.25, 0.98), P = .04), and significant improvements in complete remission (OR = 0.39, 95% CI = 0.23-0.68, P = .0007) and partial remission (OR = 0.46, 95%CI = 0.27-0.78, P = .004). The median follow-up time, acute graft-versus-host disease, and no remission had no significant difference between treatment and control groups (the median follow-up time: OR = -1.76, 95% CI (-6.28, 2.76), P = .45; acute graft-versus-host disease: OR = 0.72, 95% CI (0.50, 1.03), P = .08; no remission: OR = 3.19, 95%CI = 2.06-4.94, P = .05). Overall, the magnitude of the effect was found to be in the small to moderate range.

CONCLUSION

Decitabine combined with allo-HSCT can obtain lower recurrence risk and longer disease-free survival time, and improve the prognosis of patients. The safety is relatively stable. Due to the varying quality level of the included studies, the validation of multiple high-quality studies still needs improvement.

Naturally occurring, natural product inspired and synthetic heterocyclic anti-cancer drugs

This chapter describes the importance and activity of a huge number of commercially available naturally occurring, natural product derived or synthetic heterocyclic anti-cancer drugs.

Meta-analysis of the benefit of hypomethylating agents before allogeneic hematopoietic stem cell transplantation in myelodysplastic syndromes

Hypomethylating agents (HMAs) are effective therapies in myelodysplastic syndromes (MDS), but allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the only way to cure MDS. According to the current literature, it is difficult to confirm whether HMAs bridging therapy is beneficial for MDS patients receiving allo-HSCT. Therefore, we tried to evaluate the effect of HMAs on long-term survival of the MDS patients. Databases, including PubMed, Embase Ovid, and the Cochrane Library, were searched for studies published up to January 10, 2021. Patients who accepted HMAs bridging to allo-HSCT were defined as experimental group, while patients who received the best supportive care (BSC) before allo-HSCT were control group. Overall survival (OS) was the primary end point. Seven studies were included in the final analysis. The final results showed no OS differences between patients accepted HMAs before allo-HSCT and those received BSC (HR = 0.86, 95% CI: 0.64-1.15, p = 0.32), indicating that MDS patients' long-term survival did not benefit from HMAs bridging therapy before allo-HSCT. This conclusion needs to be further verified by a large number of prospective randomized controlled trials, which have guiding significance for the treatment of MDS patients.

Immune responses to azacytidine in animal models of inflammatory disorders: a systematic review

Inflammatory disorders like diabetes, systemic lupus erythematodes, inflammatory lung diseases, rheumatoid arthritis and multiple sclerosis, but also rejection of transplanted organs and GvHD, form a major burden of disease. Current classes of immune suppressive drugs to treat these disorders are never curative and side effects are common. Therefore there is a need for new drugs with improved and more targeted modes of action. Potential candidates are the DNA methyl transferase inhibitor 5-azacytidine (Aza) and its derivative 5-aza 2′deoxycitidine (DAC). Aza and DAC have been tested in several pre-clinical in vivo studies. In order to obtain an overview of disorders for which Aza and/or DAC can be a potential treatment, and to find out where information is lacking, we systematically reviewed pre-clinical animal studies assessing Aza or DAC as a potential therapy for distinct inflammatory disorders. Also, study quality and risk of bias was systematically assessed. In the 35 identified studies, we show that both Aza and DAC do not only seem to be able to alleviate a number of inflammatory disorders, but also prevent solid organ rejection and GvHD in in vivo pre-clinical animal models. Aza/DAC are known to upregulate FOXP3, a master transcription factor for Treg, in vitro. Seventeen studies described the effect on Treg, of which 16 studies showed an increase in Treg. Increasing Treg therefore seems to be a common mechanism in preventing inflammatory disorders by Aza/DAC. We also found, however, that many essential methodological details were poorly reported leading to an unclear risk of bias. Therefore, reported effects might be an overestimation of the true effect.

Pre-transplant hypomethylating agents do not influence post-transplant survival in myelodysplastic syndrome

Information on the use of hypomethylating agents (HMAs) as a pre-transplant cytoreductive therapy in MDS is limited. We retrospectively evaluated outcomes of 172 adult MDS patients, who underwent allogeneic hematopoietic stem cell transplantation between January 2000 and December 2016. Patients were divided into three groups: group 1 - pre-transplant blasts <5% with HMA (n = 42), group 2 - pre-transplant blasts ≥5% with HMA (n = 38), group 3 - no HMA (n = 92). With a median follow up of 4.08 years, 1-year survival and relapse rates for groups 1, 2, and 3 were 75%, 40.2%, and 60.71%, respectively; and 17.6%, 26.6%, and 9.8%, respectively. Multivariate analysis revealed adverse relapse (HR 3.54; p = .03) in group 2 compared to groups 1 and 3, while no difference in overall survival was noticed. Our study shows no survival association with pre-transplant HMA; although, higher relapse rate was observed in the non-responding patients indicating possible chemotherapy resistant disease.

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.

DNA Methylation Events as Markers for Diagnosis and Management of Acute Myeloid Leukemia and Myelodysplastic Syndrome

During the onset and progression of hematological malignancies, many changes occur in cellular epigenome, such as hypo- or hypermethylation of CpG islands in promoter regions. DNA methylation is an epigenetic modification that regulates gene expression and is a key event for tumorigenesis. The continuous search for biomarkers that signal early disease, indicate prognosis, and act as therapeutic targets has led to studies investigating the role of DNA in cancer onset and progression. This review focuses on DNA methylation changes as potential biomarkers for diagnosis, prognosis, response to treatment, and early toxicity in acute myeloid leukemia and myelodysplastic syndrome. Here, we report that distinct changes in DNA methylation may alter gene function and drive malignant cellular transformation during several stages of leukemogenesis. Most of these modifications occur at an early stage of disease and may predict myeloid/lymphoid transformation or response to therapy, which justifies its use as a biomarker for disease onset and progression. Methylation patterns, or its dynamic change during treatment, may also be used as markers for patient stratification, disease prognosis, and response to treatment. Further investigations of methylation modifications as therapeutic biomarkers, which may correlate with therapeutic response and/or predict treatment toxicity, are still warranted.

Addition of 10-Day Decitabine to Fludarabine/Total Body Irradiation Conditioning is Feasible and Induces Tumor-Associated Antigen-Specific T Cell Responses

Allogeneic hematopoietic cell transplantation (HCT) offers the possibility of curative therapy for patients with myelodysplastic syndromes (MDS), chronic myelomonocytic leukemia (CMML), and acute myelogenous leukemia (AML). However, post-HCT relapse remains a major problem, particularly in patients with high-risk cytogenetics and in patients who cannot tolerate consolidation chemotherapy (eg, due to previous toxicity). We assessed the toxicity and efficacy of 10-day decitabine (Dec), fludarabine (Flu), and 2 Gy total body irradiation (TBI) as a new conditioning regimen for allogeneic HCT in patients with MDS, CMML, or AML. Thirty patients were enrolled, including 11 with MDS, 2 with CMML, and 17 with AML. Patients received 20 mg/m(2)/day Dec on days -11 to -2, 30 mg/m(2)/day Flu on days -4 to -2, and 2 Gy TBI on day -1, followed by infusion of a donor stem cell graft on day 0. Postgrafting immunosuppression consisted of cyclosporin A and mycophenolate mofetil. At a median follow-up of 443 days, the overall survival was 53%, relapse incidence was 27%, and nonrelapse mortality was 27%. The incidence of severe acute (grade III/IV) graft-versus-host disease (GVHD) was 27%, and that of (predominantly mild) chronic GVHD was 60%. Immunomonitoring studies revealed that specific CD8(+) T cell responses against epigenetically silenced tumor-associated antigens (TAAs), including cancer-testis antigens (MAGE-A1/A2/A3 and PRAME) and RHAMM, occurred more frequently in patients who had received Dec/Flu/TBI conditioning (8 of 11 patients) compared with a control group of patients who had received only Flu/TBI conditioning (2 of 9 patients). In summary, Dec/Flu/TBI conditioning proved feasible and effective and enhanced the induction of TAA-reactive CD8(+) T cell responses in vivo, which may contribute to disease control post-transplantation.

[Retrospective efficacy analysis of decitabine bridging allogeneic hematopoietic stem cell transplantation on the treatment of myelodysplastic syndrome]

目的

评价地西他滨桥接异基因造血干细胞移植(allo-HSCT)治疗骨髓增生异常综合征(MDS)的疗效及安全性。

方法

回顾性分析2010年7月至2013年12月于苏州大学附属第一医院血液科接受allo-HSCT的MDS患者的临床特征及疗效，随机抽取25例接受地西他滨桥接allo-HSCT的MDS患者为桥接组，以同期33例未接受地西他滨行allo-HSCT的MDS患者为对照组，观察患者疗效、总生存(OS)及移植物抗宿主病（GVHD）发生情况。

结果

桥接组患者移植前骨髓完全缓解率为64.0%（25例中16例），明显高于对照组的15.1%（33例中5例），差异有统计学意义（P<0.05）；早期移植相关死亡率低于对照组（4.0%对18.2%），但差异无统计学意义（P=0.106）。桥接组移植相关死亡率及2年OS率分别为12.0%及83.0%，与对照组的30.3%及59.0%比较差异均有统计学意义（P值均<0.05）。桥接组14例患者发生急性GVHD(aGVHD)，其中Ⅰ度7例、Ⅱ度3例、Ⅲ度4例；对照组16例患者发生aGVHD，其中Ⅰ度7例、Ⅱ度8例、Ⅲ度1例。

结论

地西他滨桥接allo-HSCT治疗MDS安全且有效。

Clinical Results of Hypomethylating Agents in AML Treatment

Epigenetic changes play an important role in the development of acute myeloid leukemia (AML). Unlike gene mutations, epigenetic changes are potentially reversible, which makes them attractive for therapeutic intervention. Agents that affect epigenetics are the DNA methyltransferase inhibitors, azacitidine and decitabine. Because of their relatively mild side effects, azacitidine and decitabine are particularly feasible for the treatment of older patients and patients with co-morbidities. Both drugs have remarkable activity against AML blasts with unfavorable cytogenetic characteristics. Recent phase 3 trials have shown the superiority of azacitidine and decitabine compared with conventional care for older AML patients (not eligible for intensive treatment). Results of treatment with modifications of the standard azacitidine (seven days 75 mg/m(2) SC; every four weeks) and decitabine (five days 20 mg/m(2) IV; every four weeks) schedules have been reported. Particularly, the results of the 10-day decitabine schedule are promising, revealing complete remission (CR) rates around 45% (CR + CRi (i.e., CR with incomplete blood count recovery) around 64%) almost comparable with intensive chemotherapy. Application of hypomethylating agents to control AML at the cost of minimal toxicity is a very promising strategy to "bridge" older patients with co-morbidities to the potential curative treatment of allogeneic hematopoietic cell transplantation. In this article, we discuss the role of DNA methyltransferase inhibitors in AML.

Cytogenetics, donor type, and use of hypomethylating agents in myelodysplastic syndrome with allogeneic stem cell transplantation

We investigated the impact of patient and disease characteristics, including cytogenetics, previous therapy, and depth of response, on the outcome of allogeneic hematopoietic stem cell transplantation (HSCT) for patients with myelodysplastic syndrome (MDS). We analyzed 256 MDS patients who underwent transplantation from a matched related (n = 133) or matched unrelated (n = 123) donor after 2001. Of the 256, 78 (30.5%) did not receive cytoreductive therapy before HSCT; 40 (15.6%) received chemotherapy, 122 (47.7%) received hypomethylating agents (HMA), and 16 (6.2%) received both (chemo+HMA). Disease status at HSCT defined by International Working Criteria was complete remission in 46 (18%) patients. There were significant differences between therapy groups: there were more therapy-related MDS and higher use of matched related donor in the untreated group. The chemotherapy group had higher serum ferritin levels at HSCT. Patients were older and had more high-risk disease by revised International Prognostic Scoring in the HMA group. Despite those differences, transplantation outcomes were similar in patients who were untreated and who received cytoreductive therapy before HSCT. Three-year event-free survival (EFS) was 44.2%, 30.6%, 34.2%, and 32.8% for untreated, chemotherapy, HMA, and chemo+HMA groups, respectively (P = .50). Multivariate analyses revealed that older age (hazard ratio [HR], 1.3; P = .001); high-risk histologic subtypes, including refractory anemia with excess blasts (HR, 1.5; P = .05) and chronic myelomonocytic leukemia (HR, 2.1; P = .03), high-risk cytogenetics with monosomal karyotype (MK) (HR, 4.0; P < .0001) and high serum ferritin level at HSCT (HR, 1.8; P = .002) were poor prognostic factors for EFS. Bone marrow blast count 5% or higher at HSCT (HR, 1.6; P = .01) and MK (HR, 4.2; P < .0001) were the only prognostic factors for increased relapse incidence after HSCT. Patients with MK represented a poor prognostic group, with 3-year EFS of 11.4% and relapse incidence of 60.9%. In this analysis, various therapy approaches before HSCT did not lead to different transplantation outcomes. Cytogenetics defined by MK was able to identify a very poor prognostic groups that innovative transplantation approaches to improve outcomes are urgently needed.

Pretransplantation 5-azacitidine in high-risk myelodysplastic syndrome

We prospectively evaluated the allogeneic hematopoietic cell transplantation (HCT) outcomes in high-risk myelodysplastic syndrome (MDS) patients who received pretransplantation 5-azacitidine. Twenty-five patients evaluated for allogeneic HCT consult and considered medically eligible for a donor search were enrolled. Azacitidine was administered at 75 mg/m(2) for 5 to 7 days every 4 weeks until a suitable donor was found. A median of 3 (range, 0 to 6) cycles of 5-azacitidine were administered. Preallogeneic HCT responses to 5-azacitidine, based on the International Working Group criteria, were 48% partial response, 33% stable disease, and 19% progressive disease. Four patients did not proceed to allogeneic HCT. Twenty-one patients, a median age of 55 (range, 25 to 67) years, received allogeneic HCT after myeloablative pharmacokinetically targeted i.v. busulfan and fludarabine conditioning regimen. Donors were either HLA-matched related or unrelated, except for 1 mismatch unrelated donor. With a median follow-up of 30 months, 1-year relapse-free and overall survivals were 52% (95% confidence interval [CI], 30% to 71%) and 62% (95% CI, 38% to 79%), respectively. Preallogeneic HCT 5-azacitidine administration was well tolerated and provided reasonable disease control before allogeneic HCT. (Registered at ClinicalTrials.gov as NCT00660400).

Decitabine

Besides 5-azacytidine (azacitidine, Vidaza®), 5-aza-2'-deoxycytidine (decitabine, Dacogen®) is the most widely used inhibitor of DNA methylation, which triggers demethylation leading to consecutive reactivation of epigenetically silenced tumor suppressor genes in vitro and in vivo. Although antileukemic activity of decitabine is known for almost 40 years, its therapeutic potential in hematologic malignancies has only recently led to its approval in higher-risk MDS patients and as first-line treatment in AML patients>65 years who are not candidates for intensive chemotherapy. Several clinical trials showed promising activity of low-dose decitabine also in CML and hemoglobinopathies, whereas its efficacy in solid tumors is very limited. Clinical responses appear to be exerted both by epigenetic alterations and by induction of cell-cycle arrest and/or apoptosis. Recent and ongoing clinical trials investigate new dosing schedules, routes of administration, and combination of decitabine with other agents, including histone deacetylase inhibitors.

Clinical development of demethylating agents in hematology

The term epigenetics refers to the heritable changes in gene expression that are not associated with a change in the actual DNA sequence. Epigenetic dysregulation is linked to the pathogenesis of a number of malignancies and has been studied extensively in myelodysplastic syndromes and acute myeloid leukemia. DNA methylation is frequently altered in cancerous cells and likely results in transcriptional silencing of tumor suppressor genes. Re-expression of these genes by inhibition of the DNA methyltransferases has been successful in the treatment of benign and malignant disease. In this Review, we discuss the clinical development of demethylating agents in hematology, with a focus on azacitidine and decitabine.

The role of hypomethylating agents in myelodysplastic syndrome: changing the management paradigm

Modern treatment of myelodysplastic syndromes (MDS) with hypomethylating agents (HMAs) such as azacitidine (Vidaza) and decitabine (Dacogen) has changed the clinical landscape of these disorders. Novel drug combinations of HMAs with histone deacetylase inhibitor therapy may synergistically target different dysregulated molecular mechanisms within MDS clones. This article reviews current trial data concerning the use of the main HMAs in MDS patients where intensive chemotherapy and allogeneic stem cell transplantation is generally not an option. Collated data are presented of the clinical response outcomes, toxicity profiles and prognostic response criteria. Vidaza use in low-risk MDS cases, the selected place of allogeneic stem cell transplantation in older patients with significant comorbidity and the novel drug combination strategies for the future are discussed.

Use of azacitidine for myelodysplastic syndromes: controversial issues and practical recommendations

Azacitidine is recommended for patients with higher-risk myelodysplastic syndromes (MDS) who are not eligible for intensive therapy or for patients with lower-risk MDS who have thrombocytopenia or neutropenia or have anemia that is unresponsive to other therapies. However, standard treatment with azacitidine has not been optimized and many issues about the use of azacitidine remain unresolved. The use of azacitidine is expanding rapidly, but limited comparative clinical trial data are available to (i) define the optimal use of azacitidine in patients with higher-risk MDS or around the time of allogeneic hematopoietic stem cell transplantation, (ii) identify those patients with lower-risk MDS who may benefit from treatment, and (iii) guide physicians on alternative therapies after treatment failure. Increasing evidence suggests that the clinical features, prognostic factors, and cytogenetic profiles of patients with MDS in Asia differ significantly from those of patients in Western countries, so the aim of this review is to summarize the evidence and provide practical recommendations on the use of azacitidine in patients with MDS in the Republic of Korea. Evidence considered in this review is based on published clinical data and on the clinical experience of an expert panel from the acute myeloid leukemia/MDS Working Party of the Korean Society of Hematology.

Epigenetic therapy in allogeneic hematopoietic stem cell transplantation

DNA methylation and other epigenetic phenomena appear to be relevant in the pathogenesis of several malignant disorders. DNA methyltransferases add methyl groups to cytosine-phosphate-guanine (CpG) islandsleading to gene promoter silencing. The DNA methyltransferases inhibitors azacitidine and decitabine have anti-tumor activity against a broad range of malignancies, but have been investigated mostly in myelodysplastic syndrome. In addition, these agents have immunomodulatory effects that are under investigation in the allogeneic stem cell transplantation scenario. Both drugs have been used in the perioperative period of allogeneic transplantations with varying degrees of success. It has been hypothesized that low dose azacitidine may increase the graft-versus-leukemia effect and have a role in the maintenance of remission after allogeneic transplantation for myeloid leukemias. It is also intriguing that this favorable effect might occur while mitigating graft-versus-host disease. Here we present a review of the rapidly growing field of epigenetic manipulation using hypomethylating agents in allogeneic transplantation.

Clinical results with the DNA hypomethylating agent 5-aza-2'-deoxycytidine (decitabine) in patients with myelodysplastic syndromes: an update

Patients with myelodysplastic syndromes (MDS), especially those with high-risk disease, other comorbidities, or of advanced age, still have a limited prognosis. In addition to cytotoxic chemotherapies, hypomethylating agents such as decitabine (5-aza-2'-deoxycytidine) and azacitidine (5-azacytidine), have been approved during the past decade and represent a very important option for the treatment of MDS today. Due to their lower toxicity compared to conventional chemotherapy, hypomethylating agents are often a safe and feasible alternative also for frail patients. Decitabine has been shown to be active in numerous studies including International Prognostic Scoring System (IPSS) intermediate-1 to high risk patients, in secondary acute myeloid leukemia (AML) arising from MDS, and in MDS with poor-risk cytogenetics. Furthermore, decitabine has been studied in the allograft setting and in combination treatment regimens, and may play a role in epigenetic "priming" before conventional chemotherapy. This review summarizes the results of clinical trials and experiences with decitabine not only in first-line and single-agent treatment regimens but also as second-line treatment after prior treatment failure, in the context of the allograft setting and as part of combination treatment regimens.

Allogeneic hematopoietic stem cell transplantation versus hypomethylating agents in patients with myelodysplastic syndrome: a retrospective case-control study

Allogeneic stem cell transplantation (allo-SCT) is the only potentially curative treatment for myelodysplastic syndrome (MDS). Recently, hypomethylating agents (HMAs) have been shown to improve survival in patients with high-risk MDS. We conducted a retrospective case-control study to compare survival with these treatment modalities in patients with untreated MDS. Controls were identified using a departmental database and transplant patients were matched in at least three of the following five criteria: year of diagnosis, age, blast percentage, International Prognostic Scoring System cytogenetic risk, and time from diagnosis to treatment. Median overall survival (OS) was 26 and 25 months for, respectively, allo-SCT [(n = 53); range, 2-210 months] and HMA [(n = 40); range, 2-98 months] (P = 0.89). Four-year survival rates were 24 and 23% for allo-SCT patients and the nontransplant cohort, respectively. Patients undergoing allo-SCT after 2000 had longer median OS compared with those transplanted before 2000 (41 versus 7 months, P=0.001). These results would suggest that prospective studies are needed to delineate the timing and efficacy of allo-SCT in the HMA era.

Epigenetic therapies in MDS and AML

The use of low dose hypomethylating agents for patients with myelodysplastic syndrome (MDS) and secondary acute myeloid leukemia (AML) has had made a significant impact. In the past, therapies for these diseases were limited and patients who elected to receive treatment were subject to highly toxic, inpatient chemotherapeutics, which were often ineffective. In the era of hypomethylating agents (azacitidine and decitabine), a patient with high grade MDS or AML with multilineage dysplasia can be offered the alternative of outpatient, relatively low-toxicity therapy. Despite the fact that CR (CR) rates to such agents remain relatively low at 15-20%, a much larger percentage of patients will have clinically significant improvements in hemoglobin, platelet, and neutrophil counts while maintaining good outpatient quality of life. As our clinical experience with azanucleotides expands, questions regarding patient selection, optimal dosing strategy, latency to best response and optimal duration of therapy following disease progression remain, but there is no question that for some patients these agents offer, for a time, an almost miraculous clinical benefit. Ongoing clinical trials in combination and in sequence with conventional therapeutics, with other epigenetically active agents, or in conjunction with bone marrow transplantation continue to provide promise for optimization of these agents for patients with myeloid disease. Although the mechanism(s) responsible for the proven efficacy of these agents remain a matter of some controversy, activity is thought to stem from induction of DNA hypomethylation, direct DNA damage, or possibly even immune modulation; there is no question that they have become a permanent part of the armamentarium against myeloid neoplasms.

Allogeneic hematopoietic cell transplantation for MDS: for whom, when and how?

Hematopoietic cell transplantation (HCT) is currently the only treatment with curative potential for patients with myelodysplastic syndrome (MDS). However, treatment-related mortality and relapse have remained major barriers to uniform success. Therefore, important questions remain to be answered, such as whom to transplant, when and how. With reduced intensity conditioning (RIC) regimens, patients in their 70s and patients with comorbid conditions have been transplanted successfully, although the relapse incidence with this approach tends to be increased in comparison to high intensity regimens. Success rates are higher in patients transplanted at an early stage of their disease. Encouraging is the fact, that results with unrelated donors who are HLA-matched by high resolution typing are comparable to those achieved with HLA genotypically identical siblings. The establishment of cord blood as a source of stem cells, and the recent success with HLA-haploidentical related donors will allow the offering of HCT to virtually all patients. Dependent upon disease stage and characteristics, some 25% to 75% of transplanted patients will be cured. While 20%-30% of patients experience chronic medical problems after HCT, 70% report a "good to excellent" quality of life. New studies must focus on further reducing GVHD for all patients and on overcoming high relapse rates in patients with high risk disease.

Reduced-intensity hematopoietic stem cell transplants for malignancies: harnessing the graft-versus-tumor effect

Allogeneic hematopoietic cell transplantation combines the power of cytotoxic chemo/radiotherapy with the ability of the new immune system to seek out and destroy tumor cells. However, administration of such myeloablative transplants is fraught with risks, some of which are related to the intensive conditioning regimens. Reductions in the intensity of the administered cytotoxic therapy have demonstrated that under some circumstances, the burden of fighting tumor and enhancing stem cell engraftment can be shouldered mostly by the transplanted immune system. Reduced intensity has allowed a potentially curative therapy for hematologic malignancies to be offered to an expanded patient population. Ongoing research seeks to enhance the safety and power of this form of allogeneic immunotherapy.

Allogeneic hematopoietic cell transplantation for myelodysplastic syndrome: the past decade

Hematopoietic cell transplantation (HCT) is the only therapy with curative potential for patients with myelodysplastic syndrome. Many conditioning regimens have been developed that, along with the use of cord blood or HLA-haploidentical donors, allow doctors to offer HCT to a growing proportion of patients. New classification schemes identify more narrowly characterized risk groups, which may facilitate decisions with regard to HCT. Disease stage and cytogenetics remain the major determinants of HCT outcome. The use of peripheral blood progenitor cells may offer an advantage over marrow for engraftment and relapse prevention, but graft-versus-host disease remains a problem. The age of patients undergoing HCT has increased significantly over the past 25 years, and comorbid conditions are the major patient characteristic impacting transplant success. Recent studies show that drugs used in the non-HCT setting may be beneficial in the context of HCT.

Allogeneic stem cell transplantation for elderly patients with myelodysplastic syndrome

Allogeneic hematopoietic stem cell transplantation (SCT) is well accepted as a curative treatment approach for younger patients with myelodysplastic syndrome (MDS) and has become one of the most frequent indications for allogeneic SCT as reported to the Center for International Blood and Marrow Transplant Research. However, MDS patients are usually elderly with a median age of approximately 75 years at diagnosis. Large register studies have confirmed the feasibility of the procedure in elderly MDS patients; and in the register of the European Group for Blood and Marrow Transplantation, one-third of the allogeneic transplant procedures for MDS were performed in 2010 in patients older than 60 years. Despite its curative potential, its role in the treatment of elderly MDS patients is less defined. Because of the inherent complications of the transplantation leading to treatment-related mortality and the risk of relapse, a careful calculation of the benefit for each patient is mandatory, taking into account comorbidities, disease status, donor selection, and effective nontransplant therapies. Prospective multicenter studies are needed to define optimal intensity of the conditioning regimen, timing of transplantation within a treatment algorithm, including drug-based therapies, and posttransplant strategies to reduce the risk of relapse.

Reduced intensity allogeneic hematopoietic stem cell transplantation for MDS using tacrolimus/sirolimus-based GVHD prophylaxis

We report a consecutive series of 59 patients with MDS who underwent reduced-intensity hematopoietic stem cell transplantation (RI-HSCT) with fludarabine/melphalan conditioning and tacrolimus/sirolimus-based GVHD prophylaxis. Two-year OS, EFS, and relapse incidences were 75.1%, 65.2%, and 20.9%, respectively. The cumulative incidence of non-relapse mortality at 100 days, 1 year, and 2 years was 3.4%, 8.5%, and 10.5%, respectively. The incidence of grade II-IV acute GVHD was 35.4%; grade III-IV was 18.6%. Forty of 55 evaluable patients developed chronic GVHD; of these 35 were extensive grade. This RI-HSCT protocol produces encouraging outcomes in MDS patients, and tacrolimus/sirolimus-based GVHD prophylaxis may contribute to that promising result.

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.

Optimizing hypomethylating agents in myelodysplastic syndromes

PURPOSE OF REVIEW

Hypomethylating agents (HMAs) improve the outcome of higher-risk myelodysplastic syndromes (MDS) and provide multilineage response in lower-risk patients but their results must be optimized, especially as the poor outcome of patients after HMA failure is now established.

RECENT FINDINGS

Current efforts include evaluation of novel outpatient administration schedules and routes, improving compliance and drug exposure to reach continuous hypomethylation. Novel combination strategies are emerging, with histone deacetylase inhibitors or immunomodulatory compounds, but none has proven superior to HMA single-agent therapy so far. Improved understanding of the epigenetic deregulation of MDS and of HMA's mode of action has allowed putative biomarkers to emerge, including multiple gene methylation patterns, and gene mutations, notably TET2 mutations. As HMAs may elicit antileukemic immune responses, they are also being evaluated in patients eligible for allogeneic stem cell transplantation.

SUMMARY

The indication and practical use of HMAs in MDS so far remain those of phase III registration studies, but will hopefully be modified with future results of ongoing clinical and translational research.

Transplantation for myelodysplastic syndrome in the era of hypomethylating agents

PURPOSE OF REVIEW

This review summarizes the available data on the role of hypomethylating agents in the setting of hematopoietic cell transplantation (HCT) for myelodysplastic syndrome (MDS).

RECENT FINDINGS

Although hypomethylating agents have been established as standard of therapy for MDS in the nontransplant setting, the role of these agents in patients who are candidates for HCT or are undergoing HCT is less well defined. Hypomethylation therapy has been investigated in both the pre-HCT and post-HCT setting. Patients who are transplant candidates and are given pre-HCT hypomethylating therapy should proceed with HCT when 'best response' is achieved; HCT when hypomethylation has failed is associated with inferior outcome. Only limited data have been presented on the use of hypomethylating agents after HCT. Although this approach may prove to be useful in reducing post-HCT relapse, such therapy should only be given in the setting of clinical trials.

SUMMARY

Treatment planning for patients with MDS who are HCT candidates should comprise the entire treatment arc including pre-HCT debulking, possibly with hypomethylating agents, conditioning regimen, and potential post-HCT treatment, be it prophylactic, pre-emptive or therapeutic.

Pretransplantation therapy with azacitidine vs induction chemotherapy and posttransplantation outcome in patients with MDS

Although allogeneic hematopoietic cell transplantation (HCT) has proven curative potential for myelodysplastic syndrome, relapse after HCT remains a problem. Pretransplantation cytoreduction with induction chemotherapy (IC) has been used to reduce relapse rates but is associated with significant toxicity and mortality. Hypomethylating agents may achieve cytoreduction with limited toxicity; however, data on the effect of pre-HCT hypomethylation on post-HCT outcomes are limited. We retrospectively reviewed results in 68 patients who underwent allogeneic HCT for myelodysplastic syndrome or acute myeloid leukemia transformed from MDS. Thirty-five patients had received cytoreduction with azacitidine before HCT with either a high-dose (40%) or a reduced-intensity (60%) conditioning regimen, and 33 had undergone IC before HCT with high-dose conditioning. The estimated 1-year overall survival (OS) was 57% in the azacitidine group and 36% in the IC group. The risk of post-HCT mortality (hazard ratio, 0.68; 95% confidence interval, 0.35-1.30), nonrelapse mortality (hazard ratio, 0.99; 95% confidence interval, 0.41-2.34), and relapse (hazard ratio, 0.34; 95% confidence interval, 0.41-2.34) were lower in the azacitidine group compared to the IC group, but only the hazard for relapse was significantly lower. After adjustment for cytogenetic risk, International Prognostic Scoring System, and donor, the rates of post-HCT relapse for the 2 cohorts were similar. Although the current study was retrospective and nonrandomized and needs to be interpreted in this context, the results add to the growing evidence that pre-HCT therapy with azacitidine is associated with less toxicity than IC and may allow for similar post-HCT outcomes.

Hematopoietic stem cell transplantation for myelodysplastic syndrome: a review

Allogeneic hematopoietic stem cell transplantation (HSCT) continues to be the only curative option for myelodysplastic syndrome (MDS). Since the majority of the patients with this disease are often older and frail, treatment-related mortality and morbidity remain major obstacles to be overcome. Reduced-intensity conditioning and continued lines of investigation in the field of allogeneic transplantation are expected to ultimately improve the overall therapeutic approach to MDS. In this review we summarize current recommendations and controversies surrounding HSCT for MDS, as well as the use of novel therapeutics in the peri-transplant period.

Feasibility of hypomethylating agents followed by allogeneic hematopoietic cell transplantation in patients with myelodysplastic syndrome

The role of hypomethylating agent therapy (HMT) as a bridge to allogeneic hematopoietic cell transplantation (alloHCT) in patients with myelodysplastic syndrome (MDS) remains undetermined. We investigated the feasibility of HMT followed by alloHCT in patients with MDS. In all, 19 patients who received HMT followed by alloHCT were analyzed. A total of 7 patients were classified as low-risk and 12 as high-risk, based on World Health Organization (WHO) classification at the time of HMT. HMT consisted of decitabine in 9 patients and azacitidine in 10. After HMT, two patients achieved CR, six mCR, three hematologic improvement alone, and six SD in terms of best response. HMT did not alter WHO classification in 15 patients (79%), whereas 1 patient (5%) improved and 3 (16%) progressed to AML. Most patients (95%) received a non-myeloablative conditioning regimen based on fludarabine/BU/anti-thymocyte globulin, and peripheral blood-mobilized stem cells. Neutrophil and platelet engraftments were achieved in 95 and 79% of patients, respectively. The incidences of acute and chronic GVHD were 42 and 26%, respectively. In all, 2-year OS rates were 68%, and the overall outcomes of those who achieved CR/mCR with HMT tended to be superior to those without CR/mCR. HMT followed by alloHCT was a feasible and effective treatment strategy for patients with MDS.

Approaches to relapse after allogeneic stem cell transplantation

PURPOSE OF REVIEW

Relapse has become the leading cause of death following allogeneic hematopoietic stem cell transplantation (HSCT). Despite improved understanding of the biology that underlies the graft-versus-leukemia/tumor effect the relapse rate did not decrease over the past 20 years. In general, prognosis is poor for patients who relapsed to an allograft since effective treatment options are limited. Here, we review the available and upcoming treatment approaches for relapse.

RECENT FINDINGS

Treatment of relapse after allogeneic HSCT has been rarely investigated systematically and results differ substantially from diseases. Withdrawal of immunosuppressive medication, donor lymphocyte infusions with or without chemotherapy and/or second allogeneic HSCT are the most used options. New specific cellular approaches such as disease-specific T-cells, alloreactive natural killer cells or vaccination strategies are under investigation. Novel agents such as tyrosine-kinase inhibitors, hypomethylating agents, monoclonal antibodies, immunomodulating drugs, or proteasome-inhibitors either alone or in combination with adoptive immunotherapy are upcoming promising options, but valid data are lacking so far.

SUMMARY

With some exceptions (chronic myeloid leukemia), treatment options for patients who relapse are limited. The results are poor and the majority of patients ultimately die of their disease. More effort and research is needed to prevent and treat relapse after allogeneic HSCT.

Review of stem-cell transplantation for myelodysplastic syndromes in older patients in the context of the Decision Memo for Allogeneic Hematopoietic Stem Cell Transplantation for Myelodysplastic Syndrome emanating from the Centers for Medicare and Medicaid Services

Myelodysplastic syndromes (MDS) comprise a heterogeneous group of clonal hematopoietic stem-cell disorders that result in varying degrees of cytopenia and risk of transformation into acute leukemia. Allogeneic stem-cell transplantation (SCT) is the only known cure for this disease. The treatment is routinely used for younger patients, but only a minority of patients older than the age of 60 undergo this procedure. The overall MDS incidence is 3.3 per 100,000, but the incidence in patients older than age 70 is between 15 and 50 per 100,000. The median age at presentation is 76 years. Medicare-age patients 65 or older represent 80% of the total population receiving an MDS diagnosis. In the United States, one of the obstacles to SCT for older patients with MDS has been lack of third party reimbursement. On August 4, 2010, the Centers for Medicare and Medicaid Services released their Decision Memo for Allogeneic Hematopoietic Stem Cell Transplantation (HSCT) for Myelodysplastic Syndrome. This memo states: "Allogeneic HSCT for MDS is covered by Medicare only for beneficiaries with MDS participating in an approved clinical study that meets the criteria below…. " In this review, we will summarize what is known regarding the role of allogeneic SCT in older patients as well as other elements that should be included within clinical trials that can provide the evidence necessary to demonstrate that allogeneic SCT should be a covered benefit for Medicare beneficiaries.

Hematopoietic stem cell transplantation for treatment of myleodysplastic syndromes

Allogeneic stem cell transplantation is a potentially curative treatment for myelodysplastic syndromes. Transplants are clearly indicated in patients with intermediate-2 and high risk disease; there is controversy regarding when transplantation should be performed in patients with low and intermediate-1 risk disease. Most patients with MDS are over age 65 and Medicare has recently provisionally approved transplants, but only when performed as part of a comparative clinical trial which still must be finalized. Nonmyeloablative preparative regimens allow treatment of older patients with MDS, and novel approaches are under evaluation to reduce the risk of relapse and treatment related morbidity and mortality.

Allogeneic Hematopoietic Stem-Cell Transplantation for Myelodysplastic Syndrome

Transplantation is the only known cure for myelodysplastic syndrome (MDS). While some comparative analyses have demonstrated early transplantation to be the preferred strategy for all MDS patients, many of these analyses are biased. Using newly identified prognostic factors and models, a rational approach to transplantation can be undertaken. Factors such as transfusion dependency, cytogenetics, medical comorbidity, and World Health Organization (WHO) histologic subtype should all be considered when deciding on the role of transplantation for the MDS patient. Unresolved issues in transplantation include the impact of pre-transplant tumor debulking with traditional chemotherapeutic agents or the new DNA hypomethylating agents, and the optimal timing of reduced-intensity conditioning transplantation for older patients or for those with medical comorbidities.

NCI First International Workshop on the Biology, Prevention, and Treatment of Relapse after Allogeneic Hematopoietic Stem Cell Transplantation: Report from the Committee on Treatment of Relapse after Allogeneic Hematopoietic Stem Cell Transplantation

Relapse is a major cause of treatment failure after allogeneic hematopoietic stem cell transplantation (alloHSCT). Treatment options for relapse have been inadequate, and the majority of patients ultimately die of their disease. There is no standard approach to treating relapse after alloHSCT. Withdrawal of immune suppression and donor lymphocyte infusions are commonly used for all diseases; although these interventions are remarkably effective for relapsed chronic myelogenous leukemia, they have limited efficacy in other hematologic malignancies. Conventional and novel chemotherapy, monoclonal antibody therapy, targeted therapies, and second transplants have been utilized in a variety of relapsed diseases, but reports on these therapies are generally anecdotal and retrospective. As such, there is an immediate need for well-designed, disease-specific trials for treatment of relapse after alloHSCT. This report summarizes current treatment options under investigation for relapse after alloHSCT in a disease-specific manner. In addition, recommendations are provided for specific areas of research necessary in the treatment of relapse after alloHSCT.

Targeting DNA methylation for epigenetic therapy

Patterns of DNA methylation are established during embryonic development and faithfully copied through somatic cell divisions. Based on current understanding of DNA methylation and other interrelated epigenetic modifications, a comprehensive view of the 'epigenetic landscape' and cancer epigenome is evolving. The cancer methylome is highly disrupted, making DNA methylation an excellent target for anticancer therapies. During the last few decades, an increasing number of drugs targeting DNA methylation have been developed to increase efficacy and stability and to decrease toxicity. The earliest and the most successful epigenetic drug to date, 5-Azacytidine, is currently recommended as the first-line treatment of high-risk myelodysplastic syndromes (MDS). Encouraging results from clinical trials have prompted further efforts to elucidate epigenetic alterations in cancer, and to subsequently develop new epigenetic therapies. This review delineates the latest cancer epigenetic models, the recent discovery of hypomethylation agents as well as their application in the clinic.

Unrelated cord blood transplantation in adults with myelodysplasia or secondary acute myeloblastic leukemia: a survey on behalf of Eurocord and CLWP of EBMT

The aim of our study was to evaluate, through the Eurocord and European Group for Blood and Marrow Transplantation (EBMT) registries, outcomes and risk factors for outcomes in adult patients who underwent single or double unrelated cord blood transplantation (UCBT) for myelodysplastic syndrome (MDS) or secondary acute myeloblastic leukemia (sAML). A total of 180 adults with MDS (n=39) or sAML (n=69) were analyzed. Risk factors for outcomes were analyzed using the Fine and Gray method and the Cox model. Median age was 43 (18-72) years. In all, 77 patients (71%) received a single UCBT. Myeloablative conditioning regimen (MAC) was given to 57 (53%) patients. Median numbers of nucleated and CD34(+) cells at freezing were 3.6 × 10(7) and 1.1 × 10(5) kg. At 60 days, cumulative incidence of neutrophil recovery was 78±4% and was independently associated with the number of CD34(+) cells per kg (>1.1 × 10(5); P=0.005) and advanced disease status (blasts <5% at time of UCBT, P=0.016). A 2-year non-relapse mortality (NRM) was significantly higher after MAC (62 vs 34%; P=0.009). A 2-year disease-free-survival (DFS) and overall survival (OS) were 30 and 34%, respectively. In multivariate analysis, patients with high-risk disease (blasts >5% and International Prognostic scoring system (IPSS) intermediate-2 or high in MDS) had significant poorer DFS (hazard ratio (HR): 1.76; P=0.047). In spite of high NRM, these data indicate that UCBT is an acceptable alternative option to treat adults with high-risk MDS or sAML, without a suitable human leukocyte antigen (HLA)-matched donor.

Epigenetic approaches in the treatment of myelodysplastic syndromes: clinical utility of azacitidine

Myelodysplastic syndromes (MDS) are a varied group of diseases leading to significant morbidity and mortality. Therapy of MDS has been difficult, with supportive cares used to ameliorate symptoms, and hematopoietic stem cell transplantation the only curative option. Agents, such as the cytidine analog azacitidine, exert an effect on DNA methyltransferase leading to a reduction in DNA methylation, a process thought to be key to the pathogenesis of MDS. Recently, azacitidine has been shown to prolong survival and improve quality of life in patients with MDS, while maintaining a favorable adverse effect profile. This review highlights the scientific rationale for the use of azacitidine in addition to its application in current clinical practice for patients with MDS.

Role and timing of hematopoietic cell transplantation for myelodysplastic syndrome

Allogeneic hematopoietic cell transplantation (HCT) is the only curative treatment for patients with myelodysplastic syndromes (MDS). Most patients with MDS are older than 60 years and age-associated morbidities limit the patients’ options for curative transplant therapy. Since the development of conditioning regimens with reduced toxicity, the age limitations for HCT have waned for those patients with good performance status. This review will discuss the role of HCT for MDS based on prognostic features, the optimal timing of HCT, and outcomes based on patient age.

Demethylating Agents in the Treatment of Cancer

Gene silencing resulting from aberrant DNA methylation can lead to tumorigenesis. Therefore, drugs that inhibit or interfere with DNA methylation have been used to reactivate and induce silenced gene re-expression in malignancies. Two demethylating agents, azacitidine and decitabine, are approved for the treatment of myelodysplastic syndromes (MDS) by the U.S. Food and Drug Administration (FDA), and are now considered the standard of care in MDS. In this review, we discuss clinical data, including clinical benefits and toxicities, which led to the approval of azacitidine and decitabine. We also summarize findings from clinical trials that used these two demethylating agents in the treatment of solid tumors. Lastly, we discuss some limitations in the use of azacitidine and decitabine in cancer therapy.