Iron Overload In Myelodysplastic Syndromes Research Articles

Comprehensive Genomic Analysis Provides Further Evidence That Iron Overload Can Induce Genetic Instability in Myelodysplastic Syndromes

Introduction: Experimental and clinical data have shown that iron overload (IO) has the potential to accelerate progression of myelodysplastic syndromes (MDS) towards secondary leukemia and coincides with a lower survival rate. While genetic instability is understood as a common driver of MDS progression, the mechanisms involved have not yet been fully explored, albeit that oxidative stress is considered to be a main factor for IO related genetic instability. We aimed to investigate the influence of IO, measured by serum ferritin (SF) as a suitable surrogate parameter, on the stability of the genome of MDS patients (pts).Patients/Methods: 60 pts with proven MDS were included, cut-off for elevated SF being 275 µg/l. 29 pts had normal SF levels (median 61 µg/l [range 8-256 µg/l]), 31 pts had elevated SF levels (median 1,246 µg/l [283-6,907]); 1 out of 8 patients with SF > 1,005 µg/l tested positive for labile plasma iron (LPI). Pts were investigated for possible correlations of IO with distinct manifestations of genetic instability as shown by TP53 mutations, chromosome banding analysis, and molecular karyotyping (SNP array analysis). DNA double-strand breaks were quantified by γH2AX immunostaining on enriched CD34+ peripheral blood cells (PB). In addition, telomere length (TL) in PB granulocytes and lymphocytes was analyzed using flow-FISH, PB of 104 healthy donors being used for age-adaption. Plasma nitric oxide metabolites (nitrite, nitrate, nitroso species) are pending but will be screened for a possible correlation with SF.Results: Parameters for genomic stability were determined in the group of pts with elevated SF levels and the group of pts with normal SF levels. Through SNP array analysis, pts with increased SF levels were found to have significantly bigger total genomic aberrations (TGA) size than the subgroup with normal SF levels (median 87.5 Mbp TGA [range 0-229] vs. 0 Mbp TGA [0-155]; p = 0.005; Fig. 1). Likewise, telomere analysis showed significant more age-adapted TL shortening in granulocytes, representing the myeloid compartment, in the subgroup with increased SF levels (mean -1.81 kb) compared to patients with normal SF (0,64 kb, p = 0.003; Fig. 2). No significant TL shortening in lymphocytes of pts with normal SF was observed compared to pts with elevated SF. When only pts with marrow blasts <10% were considered, the subgroup with increased SF levels exhibited higher numbers of γH2AX-foci per CD34+ cell (median 5.7 γH2AX foci [range 2.1-8.6] vs. 1.6 γH2AX foci [0.5-3.5]; p = 0.008; Fig. 3). Elevated SF levels had no impact on the number, or type of chromosome abnormalities. Sanger sequencing identified only one patient with a TP53 mutation (SF = 1,246 µg/l); a search for smaller TP53-mutated clones by ultra-deep-sequencing is under way.Conclusion: In this MDS cohort, higher SF levels were significantly associated with bigger TGA size, premature granulocyte TL shortening, and increased numbers of γH2AX foci in CD34+ cells. These results further support the assumption that IO might be causally related to genetic instability in pts with MDS. Furthermore, our data suggest that SF levels not only above 1,000 µg/l, but also between upper limit of normal value but below 1,000 µg/L adversely affect genetic stability. Additionally, our results imply that the biological relevance of LPI for IO in MDS might be overestimated and is in need of reevaluation. Therefore, iron chelation might be relevant for pts with MDS at lower SF levels than previously thought. Whether investigation of the level of genetic instability by comprehensive genomic analysis as indicated above may be beneficial for the therapeutic decision regarding the timing of iron chelation therapy in individual pts with MDS remains to be explored. [Display omitted] [Display omitted] [Display omitted] DisclosuresAl-Ali:Celgene: Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding. Brümmendorf:Bristol Myers Squibb: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria, Research Funding; Ariad: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Patents & Royalties: Patent on the use of imatinib and hypusination inhibitors, Research Funding. Gattermann:Novartis: Honoraria, Research Funding.

Labile Plasma Iron (LPI), More Practical and More Sensitive to Iron Overload in Myelodysplastic Syndromes

Background: In order to gain an insight into LPI in iron metabolism microenvironment in MDS.Materials and Methods: We performed ELISA, quantitative RT-PCR, flow cytometry, MRI T2* assays to test LPI, iron biochemical parameters and LIC among 22 MDS patients.Results: LPI has a statistical difference (P<0.001 by ANOVA), which decreased gradually, among three groups, while no difference was found in ASF (P=0.086 by ANOVA). After DFO treatment, serum hepcidin expression increased from 301.26±59.78¦Ìg/L to 340.33±49.78¦Ìg/L (P=0.032), while hepcidin/ASF was up-regulated gradually from 0.16±0.08 to 0.22±0.03 (P=0.045). APAF-1 expression (P=0.047) and erythroid apoptosis rate (P=0.009) decreased significantly, respectively. No statistical difference was found in EPO (P=0.247) and GDF15 expression (P=0.172). LIC dropped from 9.83±4.84mg/g dry weight to 6.28±4.01mg/g dry weight (P<0.001). No significant difference was found in cardiac T2* (P=0.594). LPI has a closer connection to LIC than ASF (r=0.739, P<0.001 vs. r=0.321, P=0.034). (Figure1)Conclusion: LPI seems to be a real-time indicator which reflects body iron loading status instantaneously. Despite the limited knowledge available on LPI speciation in different types and degrees of IO, LPI measurements can be and are in fact used for identifying systemic IO and for initiating/adjusting chelation regimens.Before DFO treatment, a patient had an abnormal liver function. Along with iron chelation therapy, his LPI decreased rapidly. Meanwhile, his ALT dropped and his hemoglobin increased gradually. Furthmore, his LIC decreased after receiving DFO treatment.Lane a: LIC was 9.97mg/g dry weight on week 0.Lane b: LIC was 5.81mg/g dry weight on week 26. [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

SF3B1 Mutation Is an Independent Predictor of Parenchymal Iron Overload in Myelodysplastic Syndromes

Somatic mutations of RNA splicing machinery were identified in myelodysplastic syndromes (MDS), and a strong association was found between SF3B1 mutation and disease phenotype with ring sideroblasts. Recent studies showed that this mutation identifies a distinct group of MDS with ring sideroblasts, characterized by isolated erythroid dysplasia with a high degree of expanded but ineffective erythropoiesis, resulting in inappropriately low hepcidin levels. In this work we analyzed the relationship between SF3B1 mutation, body iron status, hepcidin level and liver and cardiac iron overload detected with MRI T2* in patients with MDS.We studied 34 patients with MDS diagnosed according to WHO criteria 2008 at the Department of Hematology, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy and at Ospedale Galliera, Genova, Italy (8 patients with RA or RCMD, 20 with RARS or RCMD-RS, 6 with RAEB-1 or -2). Serum hepcidin-25 measurements were performed by a validated Mass Spectrometry based method (SELDI-TOF MS). SF3B1 mutations were analyzed on DNA from circulating granulocytes on an Illumina HiSeq. Magnetic Resonance Imaging (MRI) examinations were performed with a validated scanner using a gradient echo T2* technique.Somatic mutations of SF3B1 were detected in 19 of 34 patients, with a median variant allele frequency of 0.40 (range 0.12-0.54). Ten of 19 SF3B1-mutated and 10 of 15 SF3B1 wild-type patients (67%) were RBC transfusion-dependent (median number of RBC transfusions 32, range 7-490).Variable hepcidin levels were found in the patients studied (median value 13.24 nM, range 3.25-75.56, versus 29.19 nM, range 3.26-66.15, in SF3B1-mutated and SF3B1 wild-type patients, respectively). We calculated the hepcidin to ferritin ratio, as a measure of adequacy of hepcidin levels relative to body iron stores, which was inversely related to the SF3B1 mutation (median value 0.015 nmol/mcg, range 0.004-0.035, versus 0.035, range 0.002-0.17, in SF3B1-mutated and SF3B1 wild-type patients, respectively, P=.04). In a multivariable regression model adjusted for RBC transfusion requirement, the hepcidin to ferritin ratio was independently associated with SF3B1 mutation (P=.042), indicating a blunted hepcidin response to iron overload in SF3B1-mutated patients.We then investigated the relationship between SF3B1 mutation status and parenchymal iron overload estimated by liver and cardiac MRI. Median hepatic T2* in the study population was 7 ms, ranging from 1.49 to 30.08. Focusing the analysis on patients with RBC transfusion-dependency, a higher prevalence of hepatic iron overload (defined as MRI T2* values less than 6.3 ms) was observed in SF3B1-mutated compared with SF3B1 wild-type patients (9/10 versus 5/10 respectively). In a multivariable regression analysis adjusted for RBC transfusion history, SF3B1 mutation was an independent predictor of hepatic T2* value (P=.038). When the analysis was limited to patients without RBC transfusion need, two SF3B1-mutated patients showed a liver iron overload, associated with mild increased in AST and ALT values. Cardiac iron overload defined as MRI T2* values less than 10 ms was detected in two out of 10 patients receiving more than 50 RBC units, both of them carrying SF3B1 mutation.In conclusion, our study shows that MDS patients carrying a somatic mutation of SF3B1 have inappropriately low hepcidin levels, resulting in parenchymal iron loading due to excessive iron absorption and reticuloendothelial release. These results suggest that SF3B1 mutation may be associated with liver iron overload even in untransfused patients, as observed in congenital iron loading anemias. These results may be relevant for decision-making concerning treatment of transfusion iron overload in MDS patients. DisclosuresNo relevant conflicts of interest to declare.

The role of magnetic resonance imaging in the evaluation of transfusional iron overload in myelodysplastic syndromes.

Myelodysplastic syndromes represent a group of heterogeneous hematopoietic neoplasms derived from an abnormal multipotent progenitor cell, characterized by a hyperproliferative bone marrow, dysplasia of the cellular hemopoietic elements and ineffective erythropoiesis. Anemia is a common finding in myelodysplastic syndrome patients, and blood transfusions are the only therapeutic option in approximately 40% of cases. The most serious side effect of regular blood transfusion is iron overload.Currently, cardiovascular magnetic resonance using T2 is routinely used to identify patients with myocardial iron overload and to guide chelation therapy, tailored to prevent iron toxicity in the heart. This is a major validated non-invasive measure of myocardial iron overloading and is superior to surrogates such as serum ferritin, liver iron, ventricular ejection fraction and tissue Doppler parameters.The indication for iron chelation therapy in myelodysplastic syndrome patients is currently controversial. However, cardiovascular magnetic resonance may offer an excellent non-invasive, diagnostic tool for iron overload assessment in myelodysplastic syndromes. Further studies are needed to establish the precise indications of chelation therapy and the clinical implications of this treatment on survival in myelodysplastic syndromes.

Guidelines for treating iron overload in myelodysplastic syndromes: a Taiwan consensus statement

Iron overload is common in myelodysplastic syndrome (MDS) patients, and an accumulation of evidence shows that iron chelation may have benefits in these patients. However, discussion and consensus about iron chelation therapy (ICT) for MDS patients is lacking in Taiwan and other Southeast Asian countries. An Expert Panel in Taiwan was organized in 2011 to develop iron overload guidelines and provide a uniform reference for physicians treating MDS patients with iron overload, with specific regard to when to initiate ICT, in which patients, and the clinical and scientific rationale behind its use.

The Evaluation of iron overload through hepcidin level and its related factors in myelodysplastic syndromes

We chose hepcidin and its related factors as evaluating indicators to determine the degrees of iron overload in myelodysplastic syndromes (MDS) patients. A total of 73 patients and 28 healthy volunteers were enrolled in this study. We performed enzyme-linked immunosorbent assay to measure both bone marrow and peripheral blood serum hepcidin. Real-time quantitative polymerase chain reaction was used to determine the gene expression of growth differentiation factor 15 and twisted gastrulation 1. Serum ferritin (SF), C-reactive protein (CRP), and erythropoietin were measured by routine standard laboratory assays. CD4+ and CD19+ lymphocytes and Th polarization were detected by flow cytometry. Twenty-four MDS patients were measured their cardiac and liver iron deposition levels through magnetic resonance imaging (MRI) T2* examination. No significant difference was found between the bone marrow hepcidin levels and peripheral blood hepcidin levels (P = 0.134). Stratified according to different World Health Organization subtypes, refractory anemia with ringed sideroblasts patients had the lowest hepcidin levels (105.40 ± 5.13 ng/ml), while refractory anemia with excess blasts-1 had the highest levels (335.71 ± 25.16 ng/ml). Stratified according to International Prognostic Scoring System and WHO Classification-based Prognostic Scoring System, there was a significant difference of hepcidin levels between low-risk group and high-risk group in two systems, respectively (P = 0.033 and 0.009). The hepcidin levels of CD4+ high-expression group were demonstrated higher than the normal expression groups (P = 0.02), but the CD19+ high-expression group did not show the same result (P = 0.206). Meanwhile, patients with a Th1 polarization trend had a high level of hepcidin versus normal group (P < 0.001). Liver iron concentration (LIC) measured by MRI T2* had a closer correlation (r = 0.582, P < 0.001) to hepcidin than serum ferritin, by stepwise regression. C-reactive protein and LIC seemed to be the key determinants of hepcidin, by multivariate regression. Inflammation plays an important role in the regulation of hepcidin expression. T-lymphocyte activation and Th polarization trend might participate in the regulatory mechanism partly. The capability of organ iron load assessment of MRI T2* seems better than that of SF. It seems that hepcidin with CRP and LIC measured by MRI T2* are potential indicators of iron overload in 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.

P-187 Combination of deferasirox and deferoxamine in management of iron overload in myelodysplastic syndromes (MDS): An update in a hepatopatic patient

P-187 Combination of deferasirox and deferoxamine in management of iron overload in myelodysplastic syndromes (MDS): An update in a hepatopatic patient

Current understanding of iron overload hazard in patients with myelodysplastic syndrome

Patients with myelodysplastic syndromes (MDS) become dependent on blood transfusions and develop into transfusional iron overload, which is exacerbated by increased absorption of dietary iron in response to ineffective erythropoiesis. However, it is uncertain whether there is an association among iron accumulation, clinical complications, and decreased likelihood of survival in MDS patients. Thereby our current understanding of the effects of transfusion dependency and iron overload in MDS are discussed. Particular emphasis should be placed on further characterizing the role of redox-active forms of labile iron and oxidative stress in iron overload, decreased life expectancy and increased risk of leukemic transformation in MDS patients with iron overload.

Iron chelation therapy in myelodysplastic syndromes: we need more evidence, not more guidelines

Iron chelation therapy in myelodysplastic syndromes: we need more evidence, not more guidelines

Pathophysiological and Clinical Aspects of Iron Chelation Therapy in MDS

The majority of patients with myelodysplastic syndromes (MDS) become transfusion-dependent during the course of disease and may thus develop transfusional iron overload. As a further contributor to iron overload there is increased absorption of dietary iron from the gut, as a consequence of ineffective erythropoiesis. Compared with thalassemia, it is less clear how frequent patients with MDS develop clinical complications of iron overload, and whether the accumulation of iron shortens their survival. This review aims to summarize our current knowledge of the detrimental effects of transfusional iron overload in MDS, point out the risks associated with iron-induced oxidative stress, describe the tools available for diagnosing iron overload, indicate the treatment options with currently available iron chelators, and discuss the measurement of labile plasma iron (LPI) as a tool to monitor the efficacy of iron chelation therapy.

Magnetic Resonance Imaging (MRI) Detection of Iron Overload In Patients with Myelodysplastic Syndrome (MDS),

Abstract 3827 Introduction:Transfusion dependent anemia and iron overload (IO) are associated with reduced survival in MDS. Serum ferritin is the most common method of assessing body iron content, but is also an inflammatory marker, and may not correlate with IO in specific organs. T2* magnetic resonance imaging (MRI) is a non-invasive method for detecting IO. The prevalence of IO in patients with MDS, as detected by T2* MRI, is currently unknown. Purpose: We designed a single center trial to evaluate the efficacy of T2* MRI in detection of IO in patients with MDS, determine the prevalence of iron overload in this disease and correlate MRI findings with iron indexes (ferritin, transferrin and labile plasma iron [LPI]). Material and methods: Patients with WHO-2008 defined MDS or chronic myelomonocytic leukemia (CMML), independent of transfusion requirements, were eligible. Patients receiving iron chelation therapy were excluded. Iron indexes were measured at the time of T2* MRI evaluation. Hepatic iron overload (HIO) was considered in patients with a hepatic iron concentration (HIC) ≥ 2 g/mg. Cardiac iron overload (CIO) was considered in patients with a T2* value < 20 milliseconds. Results: A total of 58 patients with MDS and two patients with CMML have been recruited. Three patients were not evaluated by MRI due to claustrophobia, so 57 patients remain for the analysis. Median age was 66 years (range 18–89). MDS subtypes by WHO included: refractory anemia (N=5), refractory anemia with ring sideroblasts (RARS; N=7), 5q- syndrome (N=4), refractory cytopenias with multilineage dysplasia (N=21), refractory anemia with excess blasts-I (N=7) and –II (N=7), unclassifiable MDS (N=3), CMML (N=2) and therapy-related MDS (N=1). Clinical features at time of MRI are presented in table 1. Median cardiac T2* value was 42 ms (range 19.7–70.1 ms), and only one patient had a T2* value indicative of CIO. Median HIC value was 3.9 g/mg (range 0.9–16 g/mg), and 68% of patients had HIO. Patients with HIO had higher ferritin levels (1182 ng/mL vs. 185 ng/mL, p<0.0001) and transferrin saturation (76% vs. 34%, p<0.0001), but no difference in LPI (0.13 vs. 0.12 mM, p=0.49). HIO was found in 76% of transfusion dependent patients, but in also 59% of patients without history of transfusions. Among patients with HIO but without a history of transfusions, 50% had RARS. Considering MRI as a gold standard for detecting HIO, a ferritin value ≥ 1.000 ng/ml had a positive predictive value (PPV) for HIO of 98% and a NPV of 48%; for transferrin saturation ≥ 50%, PPV was 91% and NPV was 55%. Conclusions: This is one of the largest studies evaluating IO in MDS by T2* MRI. The prevalence of iron overload in MDS is underestimated by using conventional iron indexes and T2* MRI can help in the early detection of IO. In some subtypes of MDS, such as RARS, mechanisms other than transfusion dependency lead to IO.Table 1Clinical Features at Time of MRIFeatureMedian [Range] or No. (%)Age, years66 [18–89]Male Sex31 (54)Hb, g/dL8.8 [5–12.6]WBC, x 109/L4.1 [0.45–17.6]Platelets, x 109/L104 [8–546]BM Blasts, %1.2 [0–20]Transfusion Dependency•Yes29 (50)•No17 (21)•Unknown11 (19)No. of Transfusions8 (0–84)Iron Saturation, %63 [5–100%]Ferritin, ng/ml968 [21.8–12738]Labile Plasma Iron, microM0.12 [−0.21–12.3]History of Fungal Infections4 [7] Disclosures:Santos:Janssen-Cilag: Consultancy, Speakers Bureau; United Medical: Consultancy, Speakers Bureau; Novartis: Research Funding. Hamerschlak:Novartis: Research Funding.

376 Combination of deferasirox and deferoxamine for management of iron overload in myelodysplastic syndromes in hepatopathic patient: A case report

376 Combination of deferasirox and deferoxamine for management of iron overload in myelodysplastic syndromes in hepatopathic patient: A case report

The Relevance of Iron Overload and the Appropriateness of Iron Chelation Therapy for Patients with Myelodysplastic Syndromes: A Dialogue and Debate

Accumulation of excessive amounts of iron in vulnerable organs and tissues, together with elevated plasma and intracellular concentrations of reactive iron molecules, are likely to be harmful to some patients with myelodysplastic syndromes (MDS) who have received numerous red blood cell transfusions. But what is the real magnitude of risks related to iron overload in MDS, and how strong is the evidence that reducing total body iron and labile plasma iron through treatment with chelating drugs is beneficial to patients? Available data can be interpreted in different ways, and as a result, these topics continue to be areas of heated debate among physicians who care for patients with MDS. Using the traditional but rarely employed format of a classical dialogue, I explore here the potential dangers of iron overload and the risks and benefits of iron chelation therapy for patients with MDS.

Optimizing Therapy for Iron Overload in the Myelodysplastic Syndromes

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.

Is Iron-Chelation Therapy Useful in Persons with Myelodysplastic Syndrome Receive?

Iron overload in myelodysplastic syndrome (MDS) results from multiple RBC-transfusions and inappropriate increased iron absoption associated with ineffective erythropoiesis. Data from hereditary iron-loading anemias indicate long-term consequences of iron toxicity are preventable and potentially reversible by effective iron-chelation therapy (ICT). There is increasing interest in using ICT in persons with MDS because of the recent introduction of orally effective iron-chelators which are suitable for older persons, (1-4). Ideally, evidence supporting the benefit of ICT in MDS should be evidenced-based, especially data from randomized trials showing better survival and, in exceptional cases, improved heart function . Such data are lacking. Nevertheless, it is possible to rely on the extensive data from trials of ICT in persons with thalassemia and to use well-defined predictors of increased risks of life-threatening complications to identify persons with MDS most likely to benefit from iron-chelating therapy.

Magnetic Resonance Imaging (MRI) Detection of Iron Overload In Patients with Myelodysplastic Syndrome (MDS)

AbstractAbstract 4960 Introduction:Transfusion dependent anemia and iron overload are associated with reduced survival in patients with MDS. Increased iron absorption at the gastrointestinal tract may also contribute to iron overload. Serum ferritin is the most common method of assessing body iron content, but it can be elevated in patients with inflammatory conditions, and may not correlate with iron overload in specific organs such as the heart. T2* MRI is a non-invasive method for detecting iron overload in patients with transfusion-dependent anemia, and its efficacy has been validated in patients with thalassemia major. There are few studies reporting on the efficacy of T2* MRI for detection of iron overload in patients with MDS. Objective:To evaluate the efficacy of T2* MRI in detection of iron overload in patients with MDS, the prevalence of iron overload in this disease and correlate MRI findings with iron indexes (ferritin, transferrin and non-transferrin bound iron [NTBI]). Methods:Patients with MDS or chronic myelomonocytic leukemia (CMML), independent of transfusion requirements, were recruited into a prospective, single center trial to assess the efficacy of T2* MRI for detection of iron overload in this scenario. Patients receiving iron chelation therapy were excluded. Iron indexes were measured at the time of T2* MRI evaluation. Hepatic iron overload was considered in patients with a hepatic iron concentration (HIC) ≥ 2 g/mg. Cardiac iron overload was considered in patients with a T2* value < 20 milliseconds. Mann-Whitney and Fischer exact tests were used to compare baseline continuous and categorical variables among patients with and without iron overload as assessed by HIC. Correlation between HIC and iron indexes was assessed with Spearman correlation. Results:A total of 37 patients with MDS and one patient with CMML were recruited. Three patients were not evaluated by MRI due to claustrophoby, so 35 patients remain for the analysis. Median age was 68 years (range 18–84). MDS subtypes by the WHO classification include refractory anemia (N=3), refractory anemia with ring sideroblasts (N=5), 5q- syndrome (N=3), refractory cytopenias with multilineage dysplasia (N=13), refractory anemia with excess blasts-I (N=6) and –II (N=3) and unclassifiable MDS (N=1). Information about transfusion requirement was available for 28 patients, and 14 (50%) were transfusion dependent. Twenty-two patients could be classified by the WHO Prognostic Score System (WPSS) and were categorized as very low-risk (N=6), low-risk (N=3), intermediate risk (N=6) and high risk (N=7). Median ferritin, transferrin saturation and NTBI values were 1079.6 ng/mL (range 21.8–12738 ng/mL), 63% (range 6–100%) and 0.34 microM (range 0–12.93 microM), respectively. Median cardiac T2* value was 45.3 ms (range 19.7–70.1 ms), and only one patient had a T2* value indicative of cardiac iron overload. Median HIC value was 3.31 g/mg (range 0.2–9.97 g/mg), and 66% of patients had hepatic iron overload. Patients with hepatic iron overload had higher ferritin levels (1181 ng/mL vs. 131 ng/mL, p=0.007) and transferrin saturation (64% vs. 39%, p=0.02), but no differences in NTBI (0.29 microM vs. 0.22 microM, p=0.42). Patients with elevated HIC had a higher prevalence of transfusion dependency but the difference was not significant (50% vs. 33%, p=0.67). Ferritin levels and transferrin saturation correlated with HIC (r = 0.552, p=0.001 [ferritin]; r = 0.609, p=0.001 [transferrin saturation]). Conclusion:T2* MRI can detect iron overload in patients with MDS. Iron overload in MDS cannot be solely explained by transfusion dependent anemia. The study is currently ongoing and updated results will be presented at the meeting. Disclosures:No relevant conflicts of interest to declare.

Dose Dependent Effect of Deferasirox on Hematopoietic Progeneitors of Myelodysplastic Syndrome

AbstractAbstract 3994Defarasirox (DFX) is an orally available iron chelator used for management of iron overload in myelodysplastic syndrome (MDS). Given the importance of iron in generation of reactive oxygen species (ROS) and the importance of ROS in hematopoietic progenitor regulation, we sought to examine the effect of varying doses of deferasirox on CD34+ hematopoietic progenitors from MDS patients and compare to control CD34+ progenitors from human umbilical cord blood. CD34+ hematopoietic progenitors were isolated from bone marrow specimens of patients with MDS (who had below 10% bone marrow blasts) and human umbilical cord blood. The proliferation of these progenitors cultured in growth factor-containing medium with iron chelators deferasirox (5, 10 and 20 μM) or deferoxamine (DFO) 10 μM was examined on days 3, 7, and 14 of culture. Differentiation along granulocytic, monocytic and erythroid lineages was examined by flow cytometry. Apoptosis was determined by Annexin-V surface expression. Colony formation assays were performed in methylcellulose after varying periods of exposure to DFX. Total and mitochondrial ROS levels were determined by flow cytometry after exposure to DFX at varying concentrations. Progressive dose-dependent suppression of MDS progenitor proliferation in culture was observed with DFX at dose range of 5μM to 20μM [inhibition at day 14 compared to controls with DFX 5μM 4%, 10μM 60% (p<0.01), 20μM 90% (p<0.001), n=7]. This suppression was more pronounced in MDS compared to cord blood progenitors (DFX 20μM 22% inhibition at day 14 compared to controls, n=5). There was reduced viability of MDS progenitors at 20μM concentration of DFX which increased with duration of exposure in culture (58% viability with DFX 20μM at day 14 compared with 90% for controls, p<0.001, n=7). Viability was not reduced in normal progenitors at this concentration of DFX (83% viability with DFX 20μM at day 14 compared with 85% for controls, n=5). The percentage of CD34+ cells as well as granulocytic and monocytic lineage cells were reduced after day 14 of culture at 10 and 20μM concentrations of DFX compared to 5μM in MDS specimens. Such an effect was not observed in normal cord blood progenitors. 20μM DFX as well as DFO markedly suppressed colony growth when progenitors were plated after 14 days of exposure to chelators, suggestion depletion of primitive hematopoietic progenitors. ROS levels were suppressed by 5μM DFX, but were increased above control at 20μM. DFO (10μM), also had marked suppressive effect on proliferation of MDS progenitors at days 7 and 14 of culture compared to cord blood. We conclude that exposure to the iron chelators DFX and DFO results in enhanced dose-dependent inhibition of proliferation, differentiation and survival in MDS progenitors compared to cord blood progenitors. MDS progenitors are particularly sensitive to the anti proliferative and apoptotic effects of iron chelators at concentrations above 5μM of DFX. Our data have important implications for use of DFX in MDS patients, may explain worsening of cytopenias in some MDS patients receiving DFX therapy, and suggest that lower doses of DFX started earlier in disease course may be the preferable strategy to manage iron overload. Such doses could have favorable impact on hematopoiesis and ROS- induced genomic instability in MDS. Disclosures:Pullarkat:Novartis Pharma: Consultancy, Honoraria, Research Funding, Speakers Bureau. Bhatia:Novartis Pharma: Membership on an entity's Board of Directors or advisory committees.

Controversies surrounding iron chelation therapy for MDS

The myelodysplastic syndromes (MDS) are characterized by cytopenias and acute myeloid leukemia risk. Most MDS patients eventually require transfusion of red blood cells for anemia, placing them at risk of iron overload (IOL). In beta-thalassemia major, transfusional IOL leads to organ dysfunction and death, however, with iron chelation therapy survival improved to near normal and organ function was improved. In lower risk MDS, several non-randomized studies suggest an adverse effect of IOL on survival, and that lowering iron minimizes this impact and may improve organ function. While guidelines for MDS generally recommend chelation in selected lower risk patients, data are emerging suggesting IOL may impact adversely on the outcome of higher risk MDS and stem cell transplantation (SCT) and that lowering iron may be beneficial in these patients. Trials to determine whether these effects are truly from lowering iron are currently enrolling. 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 paper, data on the impact of IOL in MDS and SCT, possible mechanisms of iron toxicity such as oxidative stress, and the impact of lowering iron on organ function and survival are reviewed.

Iron overload in MDS—pathophysiology, diagnosis, and complications

Many patients with myelodysplastic syndromes (MDS) become dependent on blood transfusions and develop transfusional iron overload, which is exacerbated by increased absorption of dietary iron in response to ineffective erythropoiesis. However, it is uncertain whether there is an association among iron accumulation, clinical complications, and decreased likelihood of survival in MDS patients. Here, we discuss our current understanding of the effects of transfusion dependency and iron overload in MDS, indicate our knowledge gaps, and suggest that particular emphasis should be placed on further characterizing the role of redox-active forms of labile iron, which may be as important as the total iron burden.