Improving clinical outcome in patients with myelodysplastic syndrome and iron overload using iron chelation therapy

Iron Chelation in Patients with Myelodysplastic Syndromes and Myeloproliferative Neoplasms-Real-World Data from the German Noninterventional Study EXCALIBUR

Myelodysplastic syndromes and myeloproliferative neoplasms both represent hematologic diseases associated with bone marrow failure often resulting in anemia. For those patients, transfusion of red blood cell (RBC) units is essential but results in iron overload (IOL) that may affect various organ functions. Therefore, iron chelation therapy plays a major role in anemic patients, not only because it reduces IOL, but also because it may improve hematopoietic function by increasing hemoglobin or diminishing the requirement for RBC transfusions. To assess the utility, efficacy, and safety of the different iron chelation medications approved in Germany, as well as to examine the effect of chelation on hematopoietic insufficiency, a prospective, multicenter, noninterventional study named EXCALIBUR was designed. In total, 502 patients from 106 German hospitals and medical practices were enrolled. A large proportion of patients switched from a deferasirox dispersible tablet to a deferasirox-film-coated tablet, mainly because of more convenient application, which was reflected in the treatment satisfaction questionnaire for medication scores. Iron chelation was effective in lowering serum ferritin levels, with the observed adverse drug reactions being in line with the known safety profile. Hematologic response occurred in a few patients, comparable to other studies that examined hematologic improvement in patients with MDS.

Management of patients with lower-risk myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a heterogeneous group of hematopoietic stem cell disorders characterized by ineffective hematopoiesis with abnormal blood cell development (dysplasia) leading to cytopenias and an increased risk for progression to acute myeloid leukemia (AML). Patients with MDS can generally be classified as lower- (LR-MDS) or higher-risk (HR-MDS). As treatment goals for patients with LR-MDS and those with HR-MDS differ significantly, appropriate diagnosis, classification, and follow-up are critical for correct disease management. In this review, we focus on the diagnosis, prognosis, and treatment options, as well as the prediction of the disease course and monitoring of treatment response in patients with LR-MDS. We discuss how next-generation sequencing, increasing knowledge on mechanisms of MDS pathogenesis, and novel therapies may change the current treatment landscape in LR-MDS and why structured assessments of responses, toxicities, and patient-reported outcomes should be incorporated into routine clinical practice.

Understanding the Potential and Risk of Bacterial Siderophores in Cancer

Siderophores are iron chelating molecules produced by nearly all organisms, most notably by bacteria, to efficiently sequester the limited iron that is available in the environment. Siderophores are an essential component of mammalian iron homeostasis and the ongoing interspecies competition for iron. Bacteria produce a broad repertoire of siderophores with a canonical role in iron chelation and the capacity to perform versatile functions such as interacting with other microbes and the host immune system. Siderophores are a vast area of untapped potential in the field of cancer research because cancer cells demand increased iron concentrations to sustain rapid proliferation. Studies investigating siderophores as therapeutics in cancer generally focused on the role of a few siderophores as iron chelators; however, these studies are limited and some show conflicting results. Moreover, siderophores are biologically conserved, structurally diverse molecules that perform additional functions related to iron chelation. Siderophores also have a role in inflammation due to their iron acquisition and chelation properties. These diverse functions may contribute to both risks and benefits as therapeutic agents in cancer. The potential of siderophore-mediated iron and bacterial modulation to be used in the treatment of cancer warrants further investigation. This review discusses the wide range of bacterial siderophore functions and their utilization in cancer treatment to further expand their functional relevance in cancer detection and treatment.

Reduction in Ferritin Concentrations among Patients Consuming a Dark-Green Leafy Vegetable-Rich, Low Inflammatory Foods Everyday (LIFE) Diet

Background

Ferritin is an iron-containing protein and acute-phase reactant, which may be elevated due to systemic iron overload or inflammation. Various diseases are associated with excess iron, but therapeutic iron chelation is suboptimal. Prior studies suggest that several plant phytochemicals possess iron-chelating properties, indicating that a plant-based diet may benefit patients with iron overload.

Objectives

The aim was to investigate whether patients who consume a nutrient-dense, dark-green leafy vegetable-rich diet, called the Low Inflammatory Foods Everyday (LIFE) diet, experience reductions in ferritin concentrations.

Methods

This was a retrospective study in which patients were intensively counseled to follow the LIFE diet. Compliance was assessed by patient interviews and serum B-carotene measurements. Primary outcomes included changes in ferritin, B-carotene, and C-reactive protein (CRP). Patients with elevated CRP concentrations at baseline were excluded in order to separate the impact of inflammation from iron overload on ferritin concentrations. Premenopausal women, who lose iron from menstruation, were also excluded.

Results

Thirty-two patients met the inclusion criteria. The median follow-up was 183 d.   Following the dietary intervention, ferritin decreased (-81 μg/L, P = 0.006) and B-carotene increased (46 μg/L, P < 0.0001), whereas CRP remained unchanged (-0.02 mg/L, P = 0.86). Adherent patients had greater reductions in ferritin compared with nonadherent patients (-138 μg/L vs. 15 μg/L, P = 0.001). Among all patients, there was an inverse relation between B-carotene and ferritin (-2.02, P = 0.03).

Conclusions

The LIFE diet, or similar dark-green leafy vegetable-rich, whole-food plant-based diets, may benefit patients with disorders of iron overload and iron-induced oxidative stress.

Deferoxamine B: A Natural, Excellent and Versatile Metal Chelator

Deferoxamine B is an outstanding molecule which has been widely studied in the past decade for its ability to bind iron and many other metal ions. The versatility of this metal chelator makes it suitable for a number of medicinal and analytical applications, from the well-known iron chelation therapy to the most recent use in sensor devices. The three bidentate hydroxamic functional groups of deferoxamine B are the centerpiece of its metal binding ability, which allows the formation of stable complexes with many transition, lanthanoid and actinoid metal ions. In addition to the ferric ion, in fact, more than 20 different metal complexes of deferoxamine b have been characterized in terms of their chemical speciation in solution. In addition, the availability of a terminal amino group, most often not involved in complexation, opens the way to deferoxamine B modification and functionalization. This review aims to collect and summarize the available data concerning the complex-formation equilibria in solutions of deferoxamine B with different metal ions. A general overview of the progress of its applications over the past decade is also discussed, including the treatment of iron overload-associated diseases, its clinical use against cancer and neurodegenerative disorders and its role as a diagnostic tool.

Efficacy and safety of iron chelator for transfusion-dependent patients with myelodysplastic syndrome: a meta-analysis

To systematically evaluate the efficacy and safety of iron chelators for transfusion-dependent patients with MDS. Thirteen cohort studies with 12,990 patients diagnosed with MDS were included in this study. According to m eta-analysis results transfusion-dependent MDS patients with secondary iron overload had a longer (HR = 0.52, 95%CI = 0.43-0.62, P < 0.001). Further subgroup analysis revealed a longer LFS (HR = 0.84, 95%CI = 0.76-0.93, P = 0.001) in MDS patients receiving iron chelators than in MDS patients not receiving iron chelators (HR = 0.52, 95%CI = 0.43-0.62, P < 0.001) and in patients with lower-risk MDS (HR = 0.50, 95%CI = 0.43-0.59, P < 0.001). Subgroup analysis of DFX showed that compared with patients not treated with iron chelators, the group receiving DFX monotherapy had significantly increased OS (HR = 0.43, 95%CI = 0.27-0.69, P < 0.001). In terms of tolerance, meta-analysis of binary variables in CAEs indicated that the occurrence of CAEs was significantly reduced by ICT (RR = 0.64, 95%CI = 0.57-0.71, P < 0.001).

Protein Carbonylation in Patients with Myelodysplastic Syndrome: An Opportunity for Deferasirox Therapy

Control of oxidative stress in the bone marrow (BM) is key for maintaining the interplay between self-renewal, proliferation, and differentiation of hematopoietic cells. Breakdown of this regulation can lead to diseases characterized by BM failure such as the myelodysplastic syndromes (MDS). To better understand the role of oxidative stress in MDS development, we compared protein carbonylation as an indicator of oxidative stress in the BM of patients with MDS and control subjects, and also patients with MDS under treatment with the iron chelator deferasirox (DFX). As expected, differences in the pattern of protein carbonylation were observed in BM samples between MDS patients and controls, with an increase in protein carbonylation in the former. Strikingly, patients under DFX treatment had lower levels of protein carbonylation in BM with respect to untreated patients. Proteomic analysis identified four proteins with high carbonylation levels in MDS BM cells. Finally, as oxidative stress-related signaling pathways can modulate the cell cycle through p53, we analyzed the expression of the p53 target gene p21 in BM cells, finding that it was significantly upregulated in patients with MDS and was significantly downregulated after DFX treatment. Overall, our results suggest that the fine-tuning of oxidative stress levels in the BM of patients with MDS might control malignant progression.

Deferasirox reduces oxidative DNA damage in bone marrow cells from myelodysplastic patients and improves their differentiation capacity

Patients with low-risk myelodysplastic syndromes (MDS) usually develop iron overload. This leads to a high level of oxidative stress in the bone marrow (BM) and increases haematopoietic cell dysfunction. Our objective was to analyse whether chelation with deferasirox (DFX) alleviates the consequences of oxidative stress and improves BM cell functionality. We analysed 13 iron-overloaded MDS patients' samples before and 4-10 months after treatment with DFX. Using multiparametric flow cytometry analysis, we measured intracellular reactive oxygen species (ROS), DNA oxidation and double strand breaks. Haematopoietic differentiation capacity was analysed by colony-forming unit (CFU) assays. Compared to healthy donors, MDS showed a higher level of intracellular ROS and DNA oxidative damage in BM cells. DNA oxidative damage decreased following DFX treatment. Furthermore, the clonogenic assays carried out before treatment suggest an impaired haematopoietic differentiation. DFX seems to improve this capacity, as illustrated by a decreased cluster/CFU ratio, which reached values similar to controls. We conclude that BM cells from MDS are subject to higher oxidative stress conditions and show an impaired haematopoietic differentiation. These adverse features seem to be partially rectified after DFX treatment.

Reactive oxygen species levels control NF-κB activation by low dose deferasirox in erythroid progenitors of low risk myelodysplastic syndromes

Anemia is a frequent cytopenia in myelodysplastic syndromes (MDS) and most patients require red blood cell transfusion resulting in iron overload (IO). Deferasirox (DFX) has become the standard treatment of IO in MDS and it displays positive effects on erythropoiesis. In low risk MDS samples, mechanisms improving erythropoiesis after DFX treatment remain unclear. Herein, we addressed this question by using liquid cultures with iron overload of erythroid precursors treated with low dose of DFX (3μM), which corresponds to DFX 5 mg/kg/day, an unusual dose used for iron chelation. We highlight a decreased apoptosis rate and an increased proportion of cycling cells, both leading to higher proliferation rates. The iron chelation properties of low dose DFX failed to activate the Iron Regulatory Proteins and to support iron depletion, but low dose DFX dampers intracellular reactive oxygen species. Furthermore low concentrations of DFX activate the NF-κB pathway in erythroid precursors triggering anti-apoptotic and anti-inflammatory signals. Establishing stable gene silencing of the Thioredoxin (TRX) 1 genes, a NF-κB modulator, showed that fine-tuning of reactive oxygen species (ROS) levels regulates NF-κB. These results justify a clinical trial proposing low dose DFX in MDS patients refractory to erythropoiesis stimulating agents.

Management of lower-risk myelodysplastic syndromes without del5q: current approach and future trends

INTRODUCTION

Myelodysplastic syndromes (MDS) are characterized by progressive bone marrow failure manifesting as blood cytopenia and a variable risk of progression into acute myeloid leukemia. MDS is heterogeneous in biology and clinical behavior. MDS are generally divided into lower-risk (LR) and higher-risk (HR) MDS. Goals of care in HR-MDS focus on changing the natural history of the disease, whereas in LR-MDS symptom control and quality of life are the main goals. Areas covered: We review the epidemiology, tools of risk assessment, and the available therapeutic modalities for LR-MDS. We discuss the use of erythropoiesis stimulating agents (ESAs), immunosuppressive therapy (IST), lenalidomide and the hypomethylating agents (HMAs). We also discuss the predictors of response, combination treatment modalities, and management of iron overload. Lastly, we overview the most promising investigational agents for LR-MDS. Expert commentary: It remains unclear how to best incorporate a wealth of new genetic and epigenetic prognostic markers into risk assessment tools especially for LR-MDS patients. Only a subset of patients respond to current treatment modalities and most responders eventually lose their response. Once standard therapeutic options fail, management becomes more challenging. Combination-based approaches have been largely unsuccessful. Among the most promising investigational are the TPO agonists, TGF- β pathway inhibitors, telomerase inhibitors, and the splicing modifiers.

Cyclosporine Combined with Levamisole for Lower-Risk Myelodysplastic Syndromes

Clinical and experimental evidence suggests an immune-mediated pathophysiology in subjects with lower-risk myelodysplastic syndromes (MDS) in whom immunosuppressive therapy may be effective. The novel immunosuppressive strategy of cyclosporine A (CsA) alternately combined with levamisole (LMS; CsA + LMS regimen) can dramatically improve the response rate and survival in aplastic anemia from those of our previous study. Herein, we retrospectively analyzed the data of 89 lower-risk MDS patients who received the CsA + LMS regimen. A total of 63 patients (70.8%) achieved either complete remission or hematological improvement at 4 months. Overall, 51, 41 and 19 patients had erythroid, platelet and neutrophil responses, respectively. Following the CsA + LMS regimen, 6 patients progressed to more advanced MDS at a median interval of 5 months (range, 3-42 months). The estimated 24-month progression-free survival was 82.2% (95% CI, 72.84-91.56) for all patients. Within the median follow-up of 18.5 months (range, 7.0-61.0), 6 patients died. In conclusion, the CsA + LMS regimen alleviated cytopenias and improved survival and freedom from evolution, suggesting that it could be reserved as an alternative choice for lower-risk MDS.

Durable Red Blood Cell Transfusion Independence in a Patient with an MDS/MPN Overlap Syndrome Following Discontinuation of Iron Chelation Therapy

Background. Hematologic improvement (HI) occurs in some patients with acquired anemias and transfusional iron overload receiving iron chelation therapy (ICT) but there is little information on transfusion status after stopping chelation. Case Report. A patient with low IPSS risk RARS-T evolved to myelofibrosis developed a regular red blood cell (RBC) transfusion requirement. There was no response to a six-month course of study medication or to erythropoietin for three months. At 27 months of transfusion dependence, she started deferasirox and within 6 weeks became RBC transfusion independent, with the hemoglobin normalizing by 10 weeks of chelation. After 12 months of chelation, deferasirox was stopped; she remains RBC transfusion independent with a normal hemoglobin 17 months later. We report the patient's course in detail and review the literature on HI with chelation. Discussion. There are reports of transfusion independence with ICT, but that transfusion independence may be sustained long term after stopping chelation deserves emphasis. This observation suggests that reduction of iron overload may have a lasting favorable effect on bone marrow failure in at least some patients with acquired anemias.

Medical complications, resource utilization and costs in patients with myelofibrosis by frequency of blood transfusion and iron chelation therapy

Iron chelation therapies (ICTs) can help eliminate iron surplus in erythrocyte transfusion-dependent (TD) patients with myelofibrosis (MF). The study assessed adjusted incidence rate ratios (aIRRs) of MF-related complications and resource utilization (RU) and adjusted mean monthly inpatient cost differences in patients with TD MF treated with versus without ICT (ICT+ vs. ICT-) using data from two healthcare claims databases. Patients with ≥ 2 MF International Classification of Diseases, 9th Revision (ICD-9) diagnosis codes ≥ 30 days apart were included. Among 571 patients with TD MF, 103 (18%) were ICT+ and 468 (82%) were ICT-. ICT+ patients had lower rates of thrombocytopenia (aIRR: 0.55; p < 0.001), pancytopenia (0.53; p < 0.001), emergency room visits (0.84 [95% confidence interval: 0.74-0.96]) and inpatient stays (0.75 [0.64-0.87]), but higher rates of outpatient visits (1.21 [1.18-1.23]). Adjusted mean complication-related inpatient cost difference per month was lower in ICT+ patients (-$1804 [$570]; p = 0.004). ICT+ patients had significantly lower rates of acute care, but higher rates of outpatient care.

Myelodysplastic syndromes

Myelodysplastic syndromes are clonal marrow stem-cell disorders, characterised by ineffective haemopoiesis leading to blood cytopenias, and by progression to acute myeloid leukaemia in a third of patients. 15% of cases occur after chemotherapy or radiotherapy for a previous cancer; the syndromes are most common in elderly people. The pathophysiology involves cytogenetic changes with or without gene mutations and widespread gene hypermethylation at advanced stages. Clinical manifestations result from cytopenias (anaemia, infection, and bleeding). Diagnosis is based on examination of blood and bone marrow showing blood cytopenias and hypercellular marrow with dysplasia, with or without excess of blasts. Prognosis depends largely on the marrow blast percentage, number and extent of cytopenias, and cytogenetic abnormalities. Treatment of patients with lower-risk myelodysplastic syndromes, especially for anaemia, includes growth factors, lenalidomide, and transfusions. Treatment of higher-risk patients is with hypomethylating agents and, whenever possible, allogeneic stem-cell transplantation.

Impact of iron overload and potential benefit from iron chelation in low-risk myelodysplastic syndrome

Myelodysplastic syndromes (MDSs) are a group of heterogeneous clonal bone marrow disorders characterized by ineffective hematopoiesis, peripheral blood cytopenias, and potential for malignant transformation. Lower/intermediate-risk MDSs are associated with longer survival and high red blood cell (RBC) transfusion requirements resulting in secondary iron overload. Recent data suggest that markers of iron overload portend a relatively poor prognosis, and retrospective analysis demonstrates that iron chelation therapy is associated with prolonged survival in transfusion-dependent MDS patients. New data provide concrete evidence of iron's adverse effects on erythroid precursors in vitro and in vivo. Renewed interest in the iron field was heralded by the discovery of hepcidin, the main serum peptide hormone negative regulator of body iron. Evidence from β-thalassemia suggests that regulation of hepcidin by erythropoiesis dominates regulation by iron. Because iron overload develops in some MDS patients who do not require RBC transfusions, the suppressive effect of ineffective erythropoiesis on hepcidin may also play a role in iron overload. We anticipate that additional novel tools for measuring iron overload and a molecular-mechanism-driven description of MDS subtypes will provide a deeper understanding of how iron metabolism and erythropoiesis intersect in MDSs and improve clinical management of this patient population.

Korean guideline for iron chelation therapy in transfusion-induced iron overload

Many Korean patients with transfusion-induced iron overload experience serious clinical sequelae, including organ damage, and require lifelong chelation therapy. However, due to a lack of compliance and/or unavailability of an appropriate chelator, most patients have not been treated effectively. Deferasirox (DFX), a once-daily oral iron chelator for both adult and pediatric patients with transfusion-induced iron overload, is now available in Korea. The effectiveness of deferasirox in reducing or maintaining body iron has been demonstrated in many studies of patients with a variety of transfusion-induced anemias such as myelodysplastic syndromes, aplastic anemia, and other chronic anemias. The recommended initial daily dose of DFX is 20 mg/kg body weight, taken on an empty stomach at least 30 min before food and serum ferritin levels should be maintained below 1000 ng/mL. To optimize the management of transfusion-induced iron overload, the Korean Society of Hematology Aplastic Anemia Working Party (KSHAAWP) reviewed the general consensus on iron overload and the Korean data on the clinical benefits of iron chelation therapy, and developed a Korean guideline for the treatment of iron overload.

Review of therapeutic options and the management of patients with myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a poorly understood group of disorders caused by one or more genetic aberrations in the bone marrow-derived cell line responsible for hematopoiesis. Recent advances in genetic medicine have offered new insights into the epigenesis as well as the prognosis of MDS, but have not resulted in new or improved curative treatment options. Bone marrow transplantation, introduced before the advent of genetic medicine, is still the only potential cure. Advances in other medical and pharmaceutical areas have broadened the scope of supportive care and disease-modifying therapies, and treating physicians now have a broad range of disease management options depending on a patient's likely prognosis. There is now clear evidence that appropriate supportive care and therapeutic intervention can improve progression-free and overall survival of MDS patients.

Iron chelation therapy in myelodysplastic syndromes: where do we stand?

Anemia leading to transfusion dependency (TD) and iron overload (IO) is commonly observed in patients with myelodysplastic syndromes (MDS). In MDS, TD and IO have been retrospectively associated with inferior survival and worse clinical outcomes, including cardiac, hepatic and endocrine dysfunction, and, in some analyses, with leukemic progression and infectious complications. Although suggested by retrospective analyses, clear prospective documentation of the beneficial effects of iron chelation therapy (ICT) on organ function and survival in MDS patients with TD and IO is currently lacking. Consequently, the role of ICT in MDS patients with TD and IO remains a very controversial aspect in the management of MDS. In this review, the authors summarize the current knowledge regarding IO in MDS and the role of ICT.

How we treat lower-risk myelodysplastic syndromes

Lower-risk myelodysplastic syndromes (MDSs) are defined as having low or intermediate 1 risk by the International Prognostic Scoring System and are characterized mainly by anemia in most cases. Supportive care--primarily red blood cell transfusions--remains an important component of their treatment, but exposes patients to insufficient correction of anemia, alloimmunization, and organ iron overload (for which the role of iron chelation remains debated). Treatment aimed at preventing anemia recurrence should therefore be used whenever possible. Erythropoiesis stimulating agents remain the first-line treatment of anemia in most lower-risk MDS without del(5q), whereas anemia of low-risk MDS with del 5q responds to lenalidomide in two-thirds of the cases, but this drug should be used cautiously because profound cytopenias may occur initially. Treatment after failure of those first-line therapies are disappointing overall, with many patients eventually requiring long-term transfusions, but encouraging results have been reported with hypomethylating agents and lenalidomide. Selected patients respond to antithymocyte globulins, and thrombopoietin receptor agonists are under investigation in lower-risk MDS with thrombocytopenia. Some patients, while remaining at a "lower risk" MDS level, have severe cytopenias and/or poor prognostic factors, found using newer prognostic parameters, or resistance to treatment, making them urgent candidates for more intensive approaches, including allogeneic stem cell transplantation.

Iron overload impairs proliferation of erythroid progenitors cells (BFU-E) from patients with myelodysplastic syndromes

In patients with myelodysplastic syndromes (MDS) iron overload caused by long-term red blood cell transfusions is an important factor for comorbidity especially in low-risk MDS. In this report we present the results of a comparative study based on colony formation assays of hematopoietic cells in MDS patients with and without iron overload. We demonstrate that iron overload suppresses the proliferation of erythroid progenitors cells (BFU-E), while the myeloid compartment (CFU-GM) was not found to be affected. Even patients with slightly elevated ferritin values show an impaired proliferation capacity in comparison to patients with normal ferritin levels. Furthermore, we show that this negative impact is reversible by sufficient iron chelation therapy.

Features of Japanese patients with myelodysplastic syndrome in an aging population of Sado Island

Myelodysplastic syndrome (MDS) is relatively common in the elderly, and aging of populations is progressing in developed nations, notably so in Japan. The major age group in Japan and Sado Island are distributed between 30 and 60 and between 50 and 80, respectively. The aim of this study was to analyze the features of MDS in the population of Sado Island to anticipate the characteristics of the disease in the near future. One-hundred and fifty-three patients (71 male, 82 female, 19-94 years old, median 73 years old) with de novo MDS between 1985 and 2005 were retrospectively evaluated. All patients were reclassified according to WHO-2001 criteria. The predictive power of the international prognostic scoring system and the WHO classification-based prognostic scoring system were evaluated. The major causes of death were leukemic transformation (38%) in refractory anemia with an excess of blasts and infection (48%) for total MDS. Age was another independent prognostic factor. Elderly patients exhibited a significantly poorer prognosis mainly due to infections such as pneumonia. Although novel remedies for MDS and hyperferremia have recently been developed, prevention of infection remains important in MDS, particularly for older patients.

Integrating care for patients with lower risk myelodysplastic syndrome

Patients with lower risk myelodysplastic syndrome (MDS) are those with low or intermediate-1 (INT-1) risk disease by the International Prognostic Scoring System (IPSS) index. Traditionally this has been a subset of patients where the philosophy of therapy has focused on improving transfusion needs. This is the result of the perception that the natural course of patients with lower risk disease is benign and the correct assumption that forms of therapy associated with early induction mortality cannot be justified. Over the last 5 years, we have witnessed significant improvements in our understanding of the natural history and therapy of patients with lower risk MDS. That said, it is not clear that any of these approaches improves survival. In this chapter, I will try to integrate information provided in other articles presented in this issue of Seminars in Oncology with new information regarding the heterogeneity of the natural history of patients with lower risk MDS and propose a framework for future research initiatives for this group of patients.

Standard therapy for patients with myelodysplastic syndromes

The myelodysplastic syndromes (MDS) are a group of clonal hematopoietic stem cell disorders characterized by cytopenias, dysplastic changes in the hematopoietic precursors, and an increased risk of evolving into acute leukemia. Treatment for patients with MDS ranges from supportive care with blood products and/or growth factors up to allogeneic stem cell transplantation. Over the past decade, several novel therapeutic agents have been approved for clinical use. In this article, the current approach for the management of patients with MDS according to their risk category is described and mainly focuses on approved novel agents.

Synthetic and natural iron chelators: therapeutic potential and clinical use

Iron-chelation therapy has its origins in the treatment of iron-overload syndromes. For many years, the standard for this purpose has been deferoxamine. Recently, considerable progress has been made in identifying synthetic chelators with improved pharmacologic properties relative to deferoxamine. Most notable are deferasirox (Exjade(®)) and deferiprone (Ferriprox(®)), which are now available clinically. In addition to treatment of iron overload, there is an emerging role for iron chelators in the treatment of diseases characterized by oxidative stress, including cardiovascular disease, atherosclerosis, neurodegenerative diseases and cancer. While iron is not regarded as the underlying cause of these diseases, it does play an important role in disease progression, either through promotion of cellular growth and proliferation or through participation in redox reactions that catalyze the formation of reactive oxygen species and increase oxidative stress. Thus, iron chelators may be of therapeutic benefit in many of these conditions. Phytochemicals, many of which bind iron, may also owe some of their beneficial properties to iron chelation. This review will focus on the advances in iron-chelation therapy for the treatment of iron-overload disease and cancer, as well as neurodegenerative and chronic inflammatory diseases. Established and novel iron chelators will be discussed, as well as the emerging role of dietary plant polyphenols that effectively modulate iron biochemistry.

Optimizing therapy for iron overload in the myelodysplastic syndromes: recent developments

The myelodysplastic syndromes (MDS) are characterized by cytopenias and risk of progression to acute myeloid leukaemia (AML). Most MDS patients eventually require transfusion of red blood cells for anaemia, placing them at risk of transfusional iron overload. In β-thalassaemia major, transfusional iron overload leads to organ dysfunction and death; however, with iron chelation therapy, organ function is improved, and survival improved to near normal and correlated with the degree of compliance with chelation. In lower-risk MDS, several nonrandomized studies suggest an adverse effect of iron overload on survival and that lowering iron with chelation may minimize this impact. Emerging data indicate that chelation may improve organ function, particularly hepatic function, and a minority of patients may have improvement in cell counts and decreased transfusion requirements. While guidelines for MDS generally recommend chelation in selected lower-risk patients, data from nonrandomized trials suggest iron overload may impact adversely on the outcome of higher-risk MDS and stem cell transplantation (SCT). This effect may be due to increased transplant-related mortality, infection and AML progression, and preliminary data suggest that lowering iron may be beneficial in this patient group. Other areas of active and future investigation include optimizing the monitoring of iron overload using imaging such as T2* MRI and measures of labile iron and oxidative stress; correlating new methods of measuring iron to clinical outcomes; clarifying the contribution of different cellular and extracellular iron pools to iron toxicity; optimizing chelation by using agents that access the appropriate iron pools to minimize the relevant clinical consequences in individual patients; and incorporating measures of quality of life and co-morbidities into clinical trials of chelation in MDS. It should be noted that chelation is costly and potentially toxic, and in MDS should be initiated after weighing potential risks and benefits for each patient until more definitive data are available. In this review, data on the impact of iron overload in MDS and SCT are discussed; for example, several noncontrolled studies show inferior survival in patients with iron overload in these clinical settings, including an increase in transplant-related mortality and infection risk. Possible mechanisms of iron toxicity include oxidative stress, which can damage cellular components, and the documented impact of lowering iron on organ function with measures such as iron chelation therapy includes an improvement in elevated liver transaminases. Lowering iron also appears to improve survival in both lower-risk MDS and SCT in nonrandomized studies. Selected aspects of iron metabolism, transport, storage and distribution that may be amenable to future intervention and improved removal of iron from important cellular sites are discussed, as are attempts to quantify quality of life and the importance of co-morbidities in measures to treat MDS, including chelation therapy.

Pharmacotherapy of myelodysplastic syndromes

IMPORTANCE OF THE FIELD

Despite the remarkable progress in the treatment of patients with myelodysplastic syndromes (MDS) in the past decade, response to the hypomethylating agents azacitidine and decitabine in non-del(5q) MDS patients remains at approximately 50%, leaving half of patients needing treatment with essentially no options. As biologic insight into the molecular pathways that account for disease evolution and clinical heterogeneity is expanded, the arsenal of potential drugs that may elicit significant response is also increasing. One of the greatest challenges for the treating physician is to decide when to initiate therapy and which therapy (approved drug or newer agents still in clinical trial) is likely to be the most beneficial. While there is no single answer to these issues, there are several approaches that may be considered, and these are addressed in this review.

AREAS COVERED IN THIS REVIEW

This review examines the clinical outcomes of the FDA-approved drugs as well as of the promising new therapies that are in current clinical trials.

WHAT THE READER WILL GAIN

The clinician now has multiple treatment options for patients with MDS. It is important to consider multiple factors before initiating therapy with disease-modifying drugs. This review presents some of the decision-making approaches that are in practice at present.

TAKE HOME MESSAGE

For the first time, various treatment options are available for patients with MDS. In light of the intense efforts now in progress, the next decade promises to be one of hope and excitement for both MDS patients and treating clinicians.

Towards a unifying, systems biology understanding of large-scale cellular death and destruction caused by poorly liganded iron: Parkinson's, Huntington's, Alzheimer's, prions, bactericides, chemical toxicology and others as examples

Exposure to a variety of toxins and/or infectious agents leads to disease, degeneration and death, often characterised by circumstances in which cells or tissues do not merely die and cease to function but may be more or less entirely obliterated. It is then legitimate to ask the question as to whether, despite the many kinds of agent involved, there may be at least some unifying mechanisms of such cell death and destruction. I summarise the evidence that in a great many cases, one underlying mechanism, providing major stresses of this type, entails continuing and autocatalytic production (based on positive feedback mechanisms) of hydroxyl radicals via Fenton chemistry involving poorly liganded iron, leading to cell death via apoptosis (probably including via pathways induced by changes in the NF-κB system). While every pathway is in some sense connected to every other one, I highlight the literature evidence suggesting that the degenerative effects of many diseases and toxicological insults converge on iron dysregulation. This highlights specifically the role of iron metabolism, and the detailed speciation of iron, in chemical and other toxicology, and has significant implications for the use of iron chelating substances (probably in partnership with appropriate anti-oxidants) as nutritional or therapeutic agents in inhibiting both the progression of these mainly degenerative diseases and the sequelae of both chronic and acute toxin exposure. The complexity of biochemical networks, especially those involving autocatalytic behaviour and positive feedbacks, means that multiple interventions (e.g. of iron chelators plus antioxidants) are likely to prove most effective. A variety of systems biology approaches, that I summarise, can predict both the mechanisms involved in these cell death pathways and the optimal sites of action for nutritional or pharmacological interventions.

New treatments for myelodysplastic syndromes

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

Deferasirox is a powerful NF-kappaB inhibitor in myelodysplastic cells and in leukemia cell lines acting independently from cell iron deprivation by chelation and reactive oxygen species scavenging

BACKGROUND

Usefulness of iron chelation therapy in myelodysplastic patients is still under debate but many authors suggest its possible role in improving survival of low-risk myelodysplastic patients. Several reports have described an unexpected effect of iron chelators, such as an improvement in hemoglobin levels, in patients affected by myelodysplastic syndromes. Furthermore, the novel chelator deferasirox induces a similar improvement more rapidly. Nuclear factor-kappaB is a key regulator of many cellular processes and its impaired activity has been described in different myeloid malignancies including myelodysplastic syndromes.

DESIGN AND METHODS

We evaluated deferasirox activity on nuclear factor-kappaB in myelodysplastic syndromes as a possible mechanism involved in hemoglobin improvement during in vivo treatment. Forty peripheral blood samples collected from myelodysplastic syndrome patients were incubated with 50 muM deferasirox for 18h.

RESULTS

Nuclear factor-kappaB activity dramatically decreased in samples showing high basal activity as well as in cell lines, whereas no similar behavior was observed with other iron chelators despite a similar reduction in reactive oxygen species levels. Additionally, ferric hydroxyquinoline incubation did not decrease deferasirox activity in K562 cells suggesting the mechanism of action of the drug is independent from cell iron deprivation by chelation. Finally, incubation with both etoposide and deferasirox induced an increase in K562 apoptotic rate.

CONCLUSIONS

Nuclear factor-kappaB inhibition by deferasirox is not seen from other chelators and is iron and reactive oxygen species scavenging independent. This could explain the hemoglobin improvement after in vivo treatment, such that our hypothesis needs to be validated in further prospective studies.

HFE genotype and iron metabolism in Chinese patients with myelodysplastic syndromes and aplastic anemia

The incidence of HFE gene mutations in myelodysplastic syndrome (MDS) cases remains controversial. In this study, we examined the HFE C282Y and H63D mutations in 271 Chinese patients with MDS, 402 with aplastic anemia (AA) and 1,615 healthy controls by polymerase chain reaction-restriction fragment length polymorphism in combination with DNA sequencing. No C282Y mutations were observed in the entire cohort. The distribution of H63D heterozygous and homozygous genotypes was not significantly different between the AA cases and the controls (9.7% versus 10.2%, 0.25% versus 0.24%, respectively). While the H63D heterozygous genotype in MDS patients was significantly lower than that in the controls (4.1% versus 10.2%, p = 0.002), the H63D homozygous genotype was not detected in the MDS patients. The results suggest that HFE gene mutations are not common genetic factors in Chinese patients with MDS and AA. We also compared iron metabolic parameters, including serum ferritin, serum iron, and transferrin saturation values, between HFE mutant and HFE wild-type groups in the absence of transfusion iron overload, but no significant difference was found in either MDS or AA patients except that the level of serum iron in AA patients was significantly higher in mutant carriers than in those with wild-type HFE (p = 0.011). Similarly, there was no significant difference between HFE mutant and HFE wild-type MDS and AA patients in clinical indices such as alanine aminotransferase, aspartate aminotransferase, fasting blood sugar values, and electrocardiogram. The results suggest that H63D mutations may not have clinical significance in Chinese patients with MDS and AA.

Iron overload in myelodysplastic syndromes: diagnosis and management

Myelodysplastic syndrome (MDS) is composed of a diverse spectrum of hematopoietic stem cell malignancies characterized by ineffective blood cell production. Many MDS patients are dependent on red blood cell (RBC) transfusions for symptomatic management of refractory anemia. Iron overload ensues when the iron acquired from transfused RBCs exceeds body storage capacity, thereby raising the risk for end organ damage. This is of greatest concern in patients with lower-risk MDS whose expected survival is measured in years. Transfusion dependence is associated with shorter survival and an increased risk for progression to acute myeloid leukemia (AML) in transfusion-dependent patients. Application of recent advances in the treatment of MDS can reduce or eliminate the need for transfusions, thus minimizing the risk of iron overload. Case control studies, prospective surveys, and phase II studies indicate that iron chelation therapy reduces iron load as measured by changes in serum ferritin and may prolong overall survival. Iron chelation strategies include oral agents such as deferasirox (Exjade, Novartis Pharmaceuticals Corp, East Hanover, NJ), deferiprone (Ferriprox, Apotex Europe BV, Leiden, the Netherlands) and, for those patients who are intolerant of or for whom oral therapy is ineffective, parenteral administration of deferoxamine (Desferal, Novartis). This review presents the data related to iron overload in MDS, including its prevalence, diagnosis, clinical impact, and management.

Iron chelation therapy in MDS: what have we learnt recently?

Patients with myelodysplastic syndromes (MDS) who receive chronic blood transfusions for anaemia are at risk of developing iron overload, which can negatively affect organ function and survival. Evidence suggests that iron chelation therapy can restore iron balance in these patients and may improve their chances of survival. Recently, several guidelines on the management of patients with MDS have been published that address iron overload and the use of iron chelation therapy. While these guidelines differ in some specific details, they generally agree that patients with lower-risk MDS are most likely to develop iron overload and therefore benefit from iron chelation therapy. The oral iron chelator, deferasirox, has been shown to reduce serum ferritin levels and labile plasma iron in patients with MDS, and has an acceptable safety profile. Unlike other iron chelators, deferasirox also appears to inhibit the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kappaB) pathway in MDS blast cells, which may lead to additional beneficial effects.

Iron chelation therapy in myelodysplastic syndromes

PURPOSE

To understand how to appropriately recognize and manage iron overload with iron chelation therapy (ICT) in patients with myelodysplastic syndromes (MDS), evaluation of the role of different agents available for management of iron overload, including efficacy, safety, and economic considerations for transfusion-dependent patients with MDS, is provided.

SUMMARY

Patients with MDS have a high incidence of anemia, which often requires treatment. Supportive care measures such as red blood cell transfusions and erythroid colony stimulating factors are mainstays of therapy. Use of long-term transfusion therapy has limitations in patients with MDS due to the risk of developing iron overload. Strategies to manage iron overload include phlebotomy and ICT with agents such as deferoxamine and deferasirox. Data evaluating pharmacologic therapy for treatment of iron overload in patients with MDS suggest timely intervention can mitigate the morbidity associated with this clinical syndrome.

CONCLUSION

Development of practical management strategies to implement and optimize ICT using deferoxamine and deferasirox will be important to provide optimal care for transfusion-dependent patients with MDS.

Tailoring iron chelation by iron intake and serum ferritin: the prospective EPIC study of deferasirox in 1744 patients with transfusion-dependent anemias

Background Following a clinical evaluation of deferasirox (Exjade) it was concluded that, in addition to baseline body iron burden, ongoing transfusional iron intake should be considered when selecting doses. The 1-year EPIC study, the largest ever investigation conducted for an iron chelator, is the first to evaluate whether fixed starting doses of deferasirox, based on transfusional iron intake, with dose titration guided by serum ferritin trends and safety markers, provides clinically acceptable chelation in patients (aged >or=2 years) with transfusional hemosiderosis from various types of anemia.

DESIGN AND METHODS

The recommended initial dose was 20 mg/kg/day for patients receiving 2-4 packed red blood cell units/month and 10 or 30 mg/kg/day was recommended for patients receiving less or more frequent transfusions, respectively. Dose adjustments were based on 3-month serum ferritin trends and continuous assessment of safety markers. The primary efficacy end-point was change in serum ferritin after 52 weeks compared with baseline.

RESULTS

The 1744 patients enrolled had the following conditions; thalassemia (n=1115), myelodysplastic syndromes (n=341), aplastic anemia (n=116), sickle cell disease (n=80), rare anemias (n=43) and other transfused anemias (n=49). Overall, there was a significant reduction in serum ferritin from baseline (-264 ng/mL; P<0.0001), reflecting dosage adjustments and ongoing iron intake. The most common (>5%) adverse events were gastrointestinal disturbances (28%) and skin rash (10%). Conclusions Analysis of this large, prospectively collected data set confirms the response to chelation therapy across various anemias, supporting initial deferasirox doses based on transfusional iron intake, with subsequent dose titration guided by trends in serum ferritin and safety markers (clinicaltrials.gov identifier: NCT00171821).

Oral iron chelators

Deferoxamine (DFO) was the standard of care for transfusional iron overload for >40 years, requiring subcutaneous infusion for 8-12 h/day, 5-7 days/week. Oral iron chelators are an important development, offering the potential to improve compliance and patients' quality of life. The oral, three-times-daily agent deferiprone appeared to be a promising advance; however, its use has been limited owing to serious adverse events, such as neutropenia and agranulocytosis. Therapy combining deferiprone with DFO has proved effective in the management of severe cardiac siderosis. Deferasirox is a novel, orally active agent that provides 24-h chelation with a once-daily dose. An extensive clinical trial program has demonstrated that deferasirox at appropriate doses is effective in reducing or maintaining iron burden in adult and pediatric patients. The clinical program demonstrated that deferasirox has a safety profile that is clinically manageable with regular monitoring.