Optimizing iron chelation strategies in beta-thalassaemia major

Understanding Rare Anemias: Emerging Frontiers for Diagnosis and Treatment

Background-This review provides a comprehensive overview of rare anemias, emphasizing their hereditary and acquired causes, diagnostic advancements, and evolving treatment strategies. It outlines the significance of rare anemias within public health, historical challenges in recognition and treatment, and the role of European initiatives like ENERCA and EuroBloodNet in advancing care. Content-This document discusses diagnostic technologies like next-generation sequencing and the impact of artificial intelligence, alongside the promising avenues of gene therapy, targeted drug treatments, and stem cell transplantation. It underscores the importance of a patient-tailored approach, advances in diagnostic tools, and the necessity for continued research, patient advocacy, and international collaboration to improve outcomes for individuals with rare anemias.

Oxidative Stress and Antioxidant Status in Adult Patients with Transfusion-Dependent Thalassemia: Correlation with Demographic, Laboratory, and Clinical Biomarkers

Iron overload in beta transfusion-dependent thalassemia (β-TDT) may provoke oxidative stress and reduction of the antioxidant defenses, with serious consequences for the disease course and complications. The present study evaluated the oxidant/antioxidant status of β-TDT patients and its correlation with demographic, clinical, laboratory, and instrumental biomarkers. The OXY-adsorbent assay and the d-ROMs (Diacron, Grosseto, Italy) were evaluated in 58 β-TDT patients (mean age: 37.55 ± 7.83 years, 28 females) enrolled in the Extension-Myocardial Iron Overload in Thalassemia Network. Iron overload was quantified with R2* magnetic resonance imaging. Mean OXY was 323.75 ± 113.19 μmol HClO/mL and 39 (67.2%) patients showed a decreased OXY-Adsorbent level (<350 μmol HClO/mL), of whom 22 (37.9%) showed severely reduced levels. Mean d-ROMs was 305.12 ± 62.19 UA; 12 (20.7%) patients showed oxidative stress, and 4 (6.9%) elevated oxidative stress. OXY showed a significant negative correlation with global and segmental cardiac iron levels. D-ROMs levels significantly correlated with markers of cardiovascular risk (aging, glycemia, and N-terminal pro-B-type natriuretic peptide). Antioxidant depletion is frequent in β-TDT patients, where OXY might serve as additive biomarker to assess heart iron status, whereas the d-ROMs might be helpful to assess the cardiovascular risk burden.

Long-Term Effects of Iron Chelating Agents on Ocular Function in Patients with Thalassemia Major

BACKGROUND

The aim of this study is to evaluate eye structures and function in patients receiving iron chelating therapy and to assess whether a correlation exists between the onset of ocular alterations and the intake of iron chelating drugs.

METHODS

A prospective cohort study was performed. Eighty-eight patients, composed of children and adults with thalassemia major (TM) who are taking or had taken iron chelating drugs (deferoxamine, deferiprone or deferasirox), have been initially enrolled in the study. The final sample featured 80 patients, including 18 children and 62 adults. These subjects received an eye examination to evaluate intraocular pressure (IOP), best corrected visual acuity (BCVA), the presence of refractive defects, cornea, anterior chamber, lens, fundus oculi, visual field and mean retinal nerve fiber layer (RNFL) thickness. Logistic regression model analysis was performed in order to assess any correlation. In addition, a literature search regarding the relation between iron chelating drugs and ocular adverse events was carried out to compare the results obtained with the evidence in the literature.

RESULTS

Logistic regression did not report a significant correlation between the intake of iron chelating drugs and the onset of anterior ocular segment alterations, lens opacities, retinal diseases, optical neuropathies, astigmatism, visual field and RNFL thickness defects. Logistic regression returned a statistically significant correlation between myopia and iron chelation therapy (p-value 0.04; OR 1.05) and also between presbyopia and total duration of therapy with deferoxamine (p-value 0.03; OR 1.21). Although intraocular pressure levels remained within the normal range, a significant correlation with the length of deferoxamine therapy has been found (p-value 0.002; association coefficient -0.12). A negative correlation between deferiprone and presbyopia has also been observed.

CONCLUSION

Iron chelation therapy is not associated with severe visual function alterations. Limitation of deferoxamine treatment can help prevent ocular complications. Deferiprone and/or deferasirox may be preferable, especially in patients over age 40 years.

Consumption of a green tea extract-curcumin drink decreases blood urea nitrogen and redox iron in β-thalassemia patients

The most important cause of death in β-thalassemia major patients is organ dysfunction due to iron deposits. Non-transferrin bound iron (NTBI), labile plasma iron (LPI) and labile iron pool are redox-active forms of iron found in thalassemia. Iron chelation therapy is adopted to counteract the resulting iron overload. Extracts of green tea (GTE) and curcumin exhibit iron-chelating and antioxidant activities in iron-loaded cells and β-thalassemic mice. We have used our GTE-CUR drink to investigate the potential amelioration of iron overload and oxidative stress in transfusion-dependent β-thalassemia (TDT) patients. The patients were enrolled for a control group without and with GTE-CUR treatments (17.3 and 35.5 mg EGCG equivalent). Along with regular chelation therapy, they were daily administered the drink for 60 d. Blood samples were collected at the beginning of the study and after 30 d and 60 d for biochemical and hematological tests. Interestingly, we found a decrease of blood urea nitrogen levels (P < 0.05), along with a tendency for a decrease of NTBI and LPI, and a delay in increasing lipid-peroxidation product levels in the GTE-CUR groups. The findings suggest that GTE-CUR could increase kidney function and diminish redox-active iron in iron overloaded β-thalassemia patients.

Establishment of a thalassaemia major quality improvement collaborative in Pakistan

OBJECTIVES

The aim of this study was to establish multidisciplinary care for patients with transfusion-dependent thalassaemia (TDT) by creating a TDT quality improvement (QI) collaborative in a resource-constrained setting. This study presents our initial experience of creating this collaborative, the baseline characteristics of the participants, the proposed QI interventions and the outcome metrics of the collaborative.

DESIGN AND SETTING

TDT QI collaborative is a database comprising patients with TDT from four centres in Karachi, Pakistan. Study variables included symptoms of cardiac or endocrine dysfunction, physical examination including anthropometry and Tanner staging, chelation therapy, results of echocardiography, T2* cardiac MRI (CMR) and serum ferritin. The main outcome of this collaborative was improvement in TDT-related morbidity and mortality. Interventions addressing the key drivers of outcome were designed and implemented.

RESULTS

At the time of reporting, the total number of patients in this database was 295. Most patients reported cardiac symptoms corresponding to New York Heart Association class 2. Approximately half (52%, n=153) of the patients demonstrated severe myocardial iron overload (T2* <10 ms). Majority of the patients (58%, n=175) were not on adequate chelation therapy. There was no difference in echocardiographic measures of systolic and diastolic left ventricle among the different spectrums of iron overloaded myocardium.

CONCLUSION

Using T2* CMR and endocrine testing, we have identified significant burden of iron siderosis in our patients with TDT. Lack of adequate iron load assessment and standardised management was observed. Interventions designed to target these key drivers of outcome are the unique part of this QI-based TDT registry.

Evaluation of Efficacy, Safety, and Satisfaction Taking Deferasirox Twice Daily Versus Once Daily in Patients With Transfusion-Dependent Thalassemia

OBJECTIVE

Deferasirox is a once-daily oral iron-chelation agent approved by the US Food and Drug Administration in November 2005. The authors aimed to evaluate efficacy, safety, and satisfaction of patients regarding twice-daily dose of deferasirox in patients with thalassemia who are resistant to once-daily regimen.

METHODS

In this historical cohort multicenter study, 34 patients with beta-thalassemia major resistant or intolerant to once-daily dose of deferasirox (35 mg/kg/d) were investigated in 2016. Patients were registered at 3 thalassemia referral centers in Shiraz, southern Iran and Tehran, the capital of Iran. All patients were followed for 1 year and monitored by regular physical examination, laboratory data, serum ferritin levels, and heart and liver T2 magnetic resonance imaging.

RESULTS

Mean age of thalassemia patients was 25.6±8.1 (8 to 40) years, including 22 female individuals and 12 male individuals. Serum ferritin levels significantly decreased during the study period (2021±955 at baseline vs. 1228±894 at the end of the study, P<0.001). Liver T2 magnetic resonance imaging of the patients demonstrated a significant improvement during the study. 73.3% of patients showed normal values at the end of study compared with 28.1% at the baseline (P<0.001). Drug side effects were reported only in 2 patients (5.8%) including 1 patient with abdominal pain and 1 with leukopenia and thrombocytopenia.

CONCLUSIONS

It seems that deferasirox can be used with increased dose and twice daily with acceptable efficacy in unresponsive or intolerant thalassemia patients to once-daily dose. Close monitoring of the patients is necessary to detect and manage any possible adverse events.

Left and Right Atrial Function and Remodeling in Beta-Thalassaemia Major

This study aimed to assess left (LA) and right atrial (RA) function in patients with beta-thalassaemia major. Thirty-eight patients (19 males) aged 34.5 ± 10.7 years and 43 (18 males) controls aged 30.3 ± 12.6 years (p = 0.12) were studied. The maximum RA and LA areas were measured using two-dimensional planimetry, while atrial and ventricular strain and strain rates were quantified using speckle-tracking echocardiography. Compared with controls, patients had significantly reduced LA and RA peak positive strain and total strain, and LA strain rate during ventricular systole and at atrial contraction (all p < 0.05). The LA and RA strain parameters were significantly associated (all p < 0.05). The maximum LA (10.2 ± 1.6 cm²/m² vs. 8.6 ± 1.3 cm²/m², p < 0.001) and RA (9.2 ± 1.2 cm²/m² vs. 7.5 ± 1.3 cm²/m², p < 0.001) areas were significantly greater in patients than controls. The LV and RV strain and early strain rates were similar between patients and controls (all p > 0.05). Four patients with significant myocardial iron overload had larger LA area (p < 0.001) than those without. Functional and structural remodeling of both the right and left atria occurs in patients with beta-thalassaemia major, even in the absence of ventricular diastolic dysfunction.

Iron Compounds as Anticancer Agents

Many ferrocene complexes have been prepared for their oncological potential. Some derive from molecules with known biological effects (taxanes, podophyllotoxine, artemisine, SAHA, etc.) while others are synthetic molecules selected for their cytotoxic effects (N-alkylaminoferrocenes and ferrocenyl alkylpyridinium). Although these complexes have received a great deal of attention, the field of iron metallodrugs is not limited to them. A number of inorganic complexes of iron(ii) and iron(iii) with possible anticancer effects have also been published, although research into their biological effects is often only at an early stage. This chapter also includes iron chelators, molecules that are administered in non-metallic form but whose cytotoxic species are their coordination complexes of iron generated in vivo. The most emblematic molecule of this family is bleomycin, used as an anticancer agent in many chemotherapies. To these can be added the iron chelates originally synthesized to treat iron overload, some of which have been shown to possess interesting anticancer properties. They have been, and continue to be, the subject of many clinical trials, whether alone or in combination. Thus, the area of iron metallodrugs includes molecules with very different structures and reactivity, studied from a number of different perspectives, but focused on increasing the number of molecules at our disposal for combatting cancer.

N-terminal-pro-b-type natriuretic peptide levels and cardiac hemosiderosis in adolescent β-thalassemia major patients

Background:

Iron-induced cardiomyopathy remains the leading cause of mortality in patients with β-thalassemia major. Iron overload cardiomyopathy, which may be reversible through iron chelation, is characterized by early diastolic dysfunction. Amino-terminal pro-brain natriuretic peptide (NT-proBNP) is a sensitive biomarker of diastolic dysfunction.

Aim:

The aim of the study is to evaluate the diagnostic value of NT-proBNP as a surrogate marker of iron overload examined with magnetic resonance imaging T2-star (MRI T2*).

Methods:

Sixty-eight β-thalassemia major patients (10–18 years) with no signs of heart failure underwent NT-proBNP measurement before routine transfusion. All participants prospectively underwent cardiac MRI T2* examination within 3 months (median 19 days). Patients were divided as cardiac hemosiderosis (cardiac MRI T2* <20 ms) and nonhemosiderosis (cardiac MRI T2* >20 ms).

Results:

Of 68 patients, the male-to-female ratio was 1:1.1 and the median age was 14.1 years (range: 10–17.8 years). NT-proBNP levels were not different between hemosiderosis and nonhemosiderosis patients (P = 0.233). Further receiver operating characteristic analysis resulted in no significant correlation of NT-proBNP and MRI T2* (area under the curve 0.393, P = 0.233).

Conclusion:

Measurement of NT-proBNP levels cannot be used for early detection of cardiac iron overload in adolescent with β-thalassemia major.

Desferal regulates hCtr1 and transferrin receptor expression through Sp1 and exhibits synergistic cytotoxicity with platinum drugs in oxaliplatin-resistant human cervical cancer cells in vitro and in vivo

The development of resistance to platinum drugs in cancer cells severely reduces the efficacy of these drugs. Thus, the discovery of novel drugs or combined strategies to overcome drug resistance is imperative. In addition to our previous finding that combined D-penicillamine with platinum drugs exerts synergistic cytotoxicity, we recently identified a novel therapeutic strategy by combining an iron chelating agent desferal with platinum drugs to overcome platinum resistance in an oxaliplatin-resistant human cervical cancer cell line, S3. Further study demonstrated that the level of platinum–DNA adduct formation positively correlated with cell death in combination of desferal with platinums than that of each drug alone in S3 cells. Decrement of human copper transporter 1 (hCtr1) and transferrin receptor 1 (TfR1) expression involved in the development of platinum resistance in S3 cells. Moreover, desferal promoted the expression of hCtr1 through the upregulation of Sp1. The overexpression of Sp1 increased the expression of NF-κB and translocated it into the nucleus to bind to the TfR1 promoter region, which subsequently increased the expression of TfR1. Importantly, the cotreatment of oxaliplatin with desferal significantly potentiated the oxaliplatin-elicited antitumoral effect in the oxaliplatin-resistant xenograft animal model without any toxic effect observed. Taken together, these results demonstrated that the combination of desferal with oxaliplatin can overcome oxaliplatin resistance through the regulation of hCtr1 and TfR1, and may have beneficial effect for treatment of patient with oxaliplatin-refractory tumors.

Neurocognitive dysfunction in children with β thalassemia major: psychometric, neurophysiologic and radiologic evaluation

OBJECTIVE

To evaluate the impact of iron chelating drugs and serum ferritin on the neurocognitive functions of patients with β thalassemia major (β-TM), using psychometric, neurophysiologic and radiologic tests.

METHODS

Eighty children with β-TM were enrolled into the study and were compared to 40 healthy controls. All participants were evaluated by measuring serum ferritin, neurocognitive assessment by Benton Visual Retention Test, Wechsler Intelligence Scale for Children, Wisconsin Card Sort Test, P300 and magnetic resonance spectroscopy (MRS).

RESULTS

WISC in our study showed that 40% of cases were borderline mental function as regards total IQ. Neurophysiologic tests were significantly impaired in patients compared to control group, with significant impairment in those receiving desferrioxamine (DFO). P300 amplitude was significantly lower in cases compared to controls (2.24 and 4.66 uv, respectively), recording the shortest amplitude in patients receiving DFO. Altered metabolic markers in the brain were detected by MRS in the form of reduced N-acetylaspartate to creatine ratio in 78.3% of our cases. There were significant correlations between psychometric tests and both neurophysiologic (P300) and radiologic (MRS) tests.

CONCLUSION

β-TM is associated with neurocognitive impairment that can be assessed by psychometric, neurophysiologic and radiologic tests. The role of hemosiderosis and iron chelation therapy on cognitive functioning still need more research.

ABBREVIATIONS

β-TM: beta thalassemia major; DFO: Dysferal; DFP: Deferiprone; DFX: Deferasirox; WISC: Wechsler Intelligence Scale for Children; VIQ: verbal IQ; PIQ: performance IQ; TIQ: total IQ; BVRT: Benton Visual Retention Test; WCST: Wisconsin Card Sort Test; MRS: Magnetic resonant spectroscopy; NAA/Cr ratio: N-acetylaspartate to creatine ratio.

Fulminant Liver Failure in a Child With β-Thalassemia on Deferasirox: A Case Report

Deferesirox (DFX), an oral chelating agent, is used to treat chronic iron overload in several hematological diseases such as β-thalassemia, sickle cell disease, and myelodysplastic anemia. DFX is generally well tolerated with the exception of gastrointestinal disturbances and rash, although cases of renal toxicity, as well as acute and chronic liver failure, have been reported in adults and children. Here we describe a 3-year-old girl with β-thalassemia undergoing treatment with DFX who presented with acute liver failure and Fanconi's syndrome. It is important for pediatric gastroenterologists, hepatologists, and hematologists to be aware that the commonly used drug DFX can lead to acute liver failure in children, and liver function should be monitored closely in all patients taking DFX.

Increased mitochondrial DNA deletions and copy number in transfusion-dependent thalassemia

BACKGROUND

Iron overload is the primary cause of morbidity in transfusion-dependent thalassemia. Increase in iron causes mitochondrial dysfunction under experimental conditions, but the occurrence and significance of mitochondrial damage is not understood in patients with thalassemia.

METHODS

Mitochondrial DNA (mtDNA) to nuclear DNA copy number (Mt/N) and frequency of the common 4977-bp mitochondrial deletion (ΔmtDNA⁴⁹⁷⁷) were quantified using a quantitative PCR assay on whole blood samples from 38 subjects with thalassemia who were receiving regular transfusions.

RESULTS

Compared with healthy controls, Mt/N and ΔmtDNA⁴⁹⁷⁷ frequency were elevated in thalassemia (P = 0.038 and P < 0.001, respectively). ΔmtDNA⁴⁹⁷⁷ was increased in the presence of either liver iron concentration > 15 mg/g dry-weight or splenectomy, with the highest levels observed in subjects who had both risk factors (P = 0.003). Myocardial iron (MRI T2* < 20 ms) was present in 0%, 22%, and 46% of subjects with ΔmtDNA⁴⁹⁷⁷ frequency < 20, 20-40, and > 40/1 × 10⁷ mtDNA, respectively (P = 0.025). Subjects with Mt/N values below the group median had significantly lower Matsuda insulin sensitivity index (5.76 ± 0.53) compared with the high Mt/N group (9.11 ± 0.95, P = 0.008).

CONCLUSION

Individuals with transfusion-dependent thalassemia demonstrate age-related increase in mtDNA damage in leukocytes. These changes are markedly amplified by splenectomy and are associated with extrahepatic iron deposition. Elevated mtDNA damage in blood cells may predict the risk of iron-associated organ damage in thalassemia.

Iron chelation monotherapy in transfusion-dependent beta-thalassemia major patients: a comparative study of deferasirox and deferoxamine

Introduction

Iron overload is the primary cause of mortality and morbidity in thalassemia major (TM) despite advances in chelation therapy. The aim of this study was to compare the effectiveness and safety of deferasirox (DFX) and deferoxamine (DFO) as iron-chelating agents in patients with transfusion-dependent β-thalassemia major.

Methods

This prospective randomized study included 60 patients with transfusion-dependent β-TM during the period from September 2014 to September 2015. Their ages were ≥ 6 years, and they had serum ferritin above 1500 μg/L and were on irregular DFO therapy. Patients had regular packed red cell transfusion in a dose of 10 mL/kg/session. They were randomized to receive DFX (single oral daily dose of 20–40 mg/kg/day) or DFO (20–50 mg/kg/day via subcutaneous infusion over 8–10 hours, 5 days a week). Iron overload was determined by serum ferritin level. The primary endpoint was decrease of serum ferritin level below 1500 μg/L. The secondary endpoint was drug safety.

Results

Both drugs significantly reduced serum ferritin (p < 0.001). At the end of follow-up, there were no significant differences between the two groups in serum ferritin levels (p = 0.673) and in percent reduction of ferritin (p = 0.315). There were no significant differences between the two groups in the total amount of blood transfusion (p = 0.166) and average iron intake (p = 0.227). There were no mortalities or any serious adverse effects, neutropenia, arthropathy, or pulmonary toxicity. Gastrointestinal upset and skin rash occurred more frequently with DFX than with DFO (p = 0.254 and 0.095, respectively).

Conclusion

With appropriate dosing and compliance with drugs, both DFX and DFO are generally well tolerated, safe, and effective in reducing serum ferritin levels in iron-overloaded, regularly-transfused thalassemia major patients. Therefore, oral DFX is recommended for more convenience and adherence to the treatment regimen.

Hepcidin: A Promising Therapeutic Target for Iron Disorders: A Systematic Review

Iron is required for most forms of organisms, and it is the most essential element for the functions of many iron-containing proteins involved in oxygen transport, cellular respiration, DNA replication, and so on. Disorders of iron metabolism are associated with diverse diseases, including anemias (e.g., iron-deficiency anemia and anemia of chronic diseases) and iron overload diseases, such as hereditary hemochromatosis and β-thalassemia. Hepcidin (encoded by Hamp gene) is a peptide hormone synthesized by hepatocytes, and it plays an important role in regulating the systematic iron homeostasis. As the systemic iron regulator, hepcidin, not only controls dietary iron absorption and iron egress out of iron storage cells, but also induces iron redistribution in various organs. Deregulated hepcidin is often seen in a variety of iron-related diseases including anemias and iron overload disorders. In the case of iron overload disorders (e.g., hereditary hemochromatosis and β-thalassemia), hepatic hepcidin concentration is significantly reduced.Since hepcidin deregulation is responsible for iron disorder-associated diseases, the purpose of this review is to summarize the recent findings on therapeutics targeting hepcidin.Continuous efforts have been made to search for hepcidin mimics and chemical compounds that could be used to increase hepcidin level. Here, a literature search was conducted in PubMed, and research papers relevant to hepcidin regulation or hepcidin-centered therapeutic work were reviewed. On the basis of literature search, we recapitulated recent findings on therapeutic studies targeting hepcidin, including agonists and antagonists to modulate hepcidin expression or its downstream signaling. We also discussed the molecular mechanisms by which hepcidin level and iron metabolism are modulated.Elevating hepcidin concentration is an optimal strategy to ameliorate iron overload diseases, and also to relieve β-thalassemia phenotypes by improving ineffective erythropoiesis. Relative to the current conventional therapies, such as phlebotomy and blood transfusion, therapeutics targeting hepcidin would open a new avenue for treatment of iron-related diseases.

Deferasirox for managing iron overload in people with myelodysplastic syndrome

BACKGROUND

The myelodysplastic syndrome (MDS) comprises a diverse group of haematopoietic stem cell disorders. Due to symptomatic anaemia, most people with MDS require supportive therapy including repeated red blood cell (RBC) transfusions. In combination with increased iron absorption, this contributes to the accumulation of iron resulting in secondary iron overload and the risk of organ dysfunction and reduced life expectancy. Since the human body has no natural means of removing excess iron, iron chelation therapy, i.e. the pharmacological treatment of iron overload, is usually recommended. However, it is unclear whether or not the newer oral chelator deferasirox leads to relevant benefit.

OBJECTIVES

To evaluate the effectiveness and safety of oral deferasirox for managing iron overload in people with myelodysplastic syndrome (MDS).

SEARCH METHODS

We searched the following databases up to 03 April 2014: MEDLINE, EMBASE, The Cochrane Library, Biosis Previews, Web of Science, Derwent Drug File and four trial registries: Current Controlled Trials (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov), ICTRP (www.who.int./ictrp/en/), and German Clinical Trial Register (www.drks.de).

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing deferasirox with no therapy, placebo or with another iron-chelating treatment schedule.

DATA COLLECTION AND ANALYSIS

We did not identify any trials eligible for inclusion in this review.

MAIN RESULTS

No trials met our inclusion criteria. However, we identified three ongoing and one completed trial (published as an abstract only and in insufficient detail to permit us to decide on inclusion) comparing deferasirox with deferoxamine, placebo or no treatment.

AUTHORS' CONCLUSIONS

We planned to report evidence from RCTs that evaluated the effectiveness of deferasirox compared to either placebo, no treatment or other chelating regimens, such as deferoxamine, in people with MDS. However, we did not identify any completed RCTs addressing this question.We found three ongoing and one completed RCT (published as an abstract only and in insufficient detail) comparing deferasirox with deferoxamine, placebo or no treatment and data will hopefully be available soon. These results will be important to inform physicians and patients on the advantages and disadvantages of this treatment option.

Manipulation of the hepcidin pathway for therapeutic purposes

Hepcidin, the liver-produced peptide hormone, is a principal regulator of iron homeostasis. Abnormal hepcidin production has emerged as a causative factor in several common iron disorders. Hepcidin insufficiency results in iron overload in hereditary hemochromatosis and iron-loading anemias, whereas hepcidin excess causes or contributes to the development of iron-restricted anemias in inflammatory diseases, infections, some cancers and chronic kidney disease. Not surprisingly, hepcidin and related pathways have become the target for the development of novel therapeutics for iron disorders. In this review, we will summarize the strategies and development programs that have been devised for agonizing or antagonizing hepcidin and its receptor ferroportin.

The pathophysiology and pharmacology of hepcidin

Inappropriate production of the iron-regulatory hormone hepcidin contributes to the pathogenesis of common iron disorders. Absolute or relative deficiency of hepcidin causes iron overload in hereditary hemochromatosis and iron-loading anemias. Elevated hepcidin causes iron restriction in inflammatory conditions including autoimmune disease, critical illness, some cancers, and chronic kidney disease. Multiple agents targeting hepcidin and its regulators are under development as novel therapeutics for iron disorders. This review summarizes hepcidin biology and discusses the current landscape for hepcidin-targeting therapeutic strategies.

Iron chelation and multiple sclerosis

Histochemical and MRI studies have demonstrated that MS (multiple sclerosis) patients have abnormal deposition of iron in both gray and white matter structures. Data is emerging indicating that this iron could partake in pathogenesis by various mechanisms, e.g., promoting the production of reactive oxygen species and enhancing the production of proinflammatory cytokines. Iron chelation therapy could be a viable strategy to block iron-related pathological events or it can confer cellular protection by stabilizing hypoxia inducible factor 1α, a transcription factor that normally responds to hypoxic conditions. Iron chelation has been shown to protect against disease progression and/or limit iron accumulation in some neurological disorders or their experimental models. Data from studies that administered a chelator to animals with experimental autoimmune encephalomyelitis, a model of MS, support the rationale for examining this treatment approach in MS. Preliminary clinical studies have been performed in MS patients using deferoxamine. Although some side effects were observed, the large majority of patients were able to tolerate the arduous administration regimen, i.e., 6-8 h of subcutaneous infusion, and all side effects resolved upon discontinuation of treatment. Importantly, these preliminary studies did not identify a disqualifying event for this experimental approach. More recently developed chelators, deferasirox and deferiprone, are more desirable for possible use in MS given their oral administration, and importantly, deferiprone can cross the blood-brain barrier. However, experiences from other conditions indicate that the potential for adverse events during chelation therapy necessitates close patient monitoring and a carefully considered administration regimen.

Studies of interaction between terbium(III)-deferasirox and double helix DNA by spectral and electrochemical methods

DNA binding studies of terbium(III)-deferasirox (Tb3+-DFX) complex were monitored to understand the reaction mechanism and introduce a new probe for the assay of DNA. In the present work, UV absorption spectrophotometry, fluorescence spectroscopy, circular dichroism (CD), cyclic voltammetry (CV) and viscosity measurement were employed to study the interactions of Tb3+-DFX with calf thymus DNA (ctDNA). The binding of Tb3+-DFX complex to ctDNA showed a hyperchromic effect in the absorption spectra and the increase in fluorescence quenching effect (amount) of Tb3+-DFX complex in the presence of ctDNA. The binding constants (Kb) for the complex with ctDNA were estimated to be 1.8×10(4) M(-1) through UV absorption spectrophotometry and fluorescence spectroscopy. Upon addition of the complex, clear decreases were observed in the viscosity of ctDNA. The CD spectra indicated that there are certain detectable conformational changes in the DNA double helix when the complex was added. The CV method showed that both anodic and cathodic peak potentials of Tb3+-DFX complex showed negative shifts on the addition of the ctDNA. Further, competitive methylene blue binding studies with fluorescence spectroscopy have shown that the complex can bind to ctDNA through nonintercalative mode. The experimental results suggest that Tb3+-DFX complex binds to DNA via groove binding and/or electrostatic binding mode.

Chelation of thallium by combining deferasirox and desferrioxamine in rats

The hypothesis that two known chelators deferasirox (4-[3,5-bis(2-hydroxyphenyl)-1,2,4-triazol-1-yl]-benzoic acid) and desferrioxamine (DFO) might be more efficient as combined treatment than as monotherapies in removing thallium from the body was tested in a new acute rat model. 7-week-old male Wistar rats received chelators: deferasirox (orally), DFO (intraperitoneal; i.p.), or deferasirox + DFO as 75 or 150 mg/kg dose half an hour after a single i.p. administration of 8 mg thallium/kg body weight in the form of chloride. Serum thallium concentration, urinary thallium, and iron excretions were determined by graphite furnace atomic absorption spectrometry. Both chelators were effective only at the higher dose level, while DFO was more effective than deferasirox in enhancing urinary thallium excretion, deferasirox was more effective than DFO in enhancing urinary iron excretion. In the combined treatment group, deferasirox did not increase the DFO effect on thallium and DFO did not increase the effect of deferasirox on iron elimination. Our results support the usefulness of this animal model for preliminary in vivo testing of thallium chelators. Urinary values were more useful because of the high variability of serum results.

A new deferiprone controlled release system obtained by ultrasound-assisted compression

OBJECTIVES

This study implements the design of an innovative dosage form using ultrasound-assisted compression of thermoplastic polymers and the development of controlled release tablets for the oral administration of deferiprone in two doses per day.

METHODS

Binary matrix tablets containing deferiprone and thermoplastic polymers have been prepared using an ultrasound-assisted tableting machine. Scanning electron microscopy has been employed to determine a sintering phenomenon of the excipients. Water uptake and drug release studies have been carried out to evaluate the ability of the polymers to control the drug release.

RESULTS

SEM micrographs showed that some polymers underwent the sintering process and the in vitro dissolution test showed good fit of the release data from these tablets to the zero-order kinetic model.

CONCLUSIONS

Carbopol 974P and 971P have been selected as matrix forming polymers for the final formulation. The polymer percolation threshold has been exceeded with 15% w/w of polymer. Therefore, sustained release tablets have been developed with only 15% of excipient. This implies that matrix tablets containing 750 mg of API, intended for two administrations a day, can be obtained with a similar weight to those existing in the market containing 500 mg of API for three administrations a day.

Longitudinal analysis of heart and liver iron in thalassemia major patients according to chelation treatment

Iron chelators and nuclear magnetic resonance imaging (MRI) techniques for assessing iron loading in liver and heart have greatly improved survival of thalassemic patients suffering iron overload-associated cardiomyopathy. However, the correlation between liver iron concentration and myocardial siderosis is ambiguous. Using an objective metric of time delay, scientists have demonstrated a lag in the loading and unloading of cardiac iron with respect to that of the liver. In the present study, we further tested this hypothesis with different chelation treatments. We analyzed the effect of three chelating treatment approaches on liver and cardiac iron content in 24 highly compliant patients who underwent 3 or more MRIs under each chelation treatment. Of the 84 MRIs considered, 32 were performed on deferoxamine (DFO - 8 patients), 24 on deferiprone (DFP - 7 patients), and 28 on combined therapy (DFO+DFP - 9 patients). In patients treated with DFO, changes in cardiac iron significantly lagged changes in liver iron but the opposite pattern was observed in patients treated with DFP (p=0.005), while combined therapy showed a pattern in-between DFO and DFP. We conclude that the temporality of changes of cardiac and liver iron is chelator-dependent, so that chelation therapy can be tailored to balance iron elimination from the liver and the heart.

Cardiovascular function and treatment in β-thalassemia major: a consensus statement from the American Heart Association

This aim of this statement is to report an expert consensus on the diagnosis and treatment of cardiac dysfunction in β-thalassemia major (TM). This consensus statement does not cover other hemoglobinopathies, including thalassemia intermedia and sickle cell anemia, in which a different spectrum of cardiovascular complications is typical. There are considerable uncertainties in this field, with a few randomized controlled trials relating to treatment of chronic myocardial siderosis but none relating to treatment of acute heart failure. The principles of diagnosis and treatment of cardiac iron loading in TM are directly relevant to other iron-overload conditions, including in particular Diamond-Blackfan anemia, sideroblastic anemia, and hereditary hemochromatosis. Heart failure is the most common cause of death in TM and primarily results from cardiac iron accumulation. The diagnosis of ventricular dysfunction in TM patients differs from that in nonanemic patients because of the cardiovascular adaptation to chronic anemia in non-cardiac-loaded TM patients, which includes resting tachycardia, low blood pressure, enlarged end-diastolic volume, high ejection fraction, and high cardiac output. Chronic anemia also leads to background symptomatology such as dyspnea, which can mask the clinical diagnosis of cardiac dysfunction. Central to early identification of cardiac iron overload in TM is the estimation of cardiac iron by cardiac T2* magnetic resonance. Cardiac T2* <10 ms is the most important predictor of development of heart failure. Serum ferritin and liver iron concentration are not adequate surrogates for cardiac iron measurement. Assessment of cardiac function by noninvasive techniques can also be valuable clinically, but serial measurements to establish trends are usually required because interpretation of single absolute values is complicated by the abnormal cardiovascular hemodynamics in TM and measurement imprecision. Acute decompensated heart failure is a medical emergency and requires urgent consultation with a center with expertise in its management. The first principle of management of acute heart failure is control of cardiac toxicity related to free iron by urgent commencement of a continuous, uninterrupted infusion of high-dose intravenous deferoxamine, augmented by oral deferiprone. Considerable care is required to not exacerbate cardiovascular problems from overuse of diuretics or inotropes because of the unusual loading conditions in TM. The current knowledge on the efficacy of removal of cardiac iron by the 3 commercially available iron chelators is summarized for cardiac iron overload without overt cardiac dysfunction. Evidence from well-conducted randomized controlled trials shows superior efficacy of deferiprone versus deferoxamine, the superiority of combined deferiprone with deferoxamine versus deferoxamine alone, and the equivalence of deferasirox versus deferoxamine.

Combined chelation therapy with deferasirox and deferoxamine in thalassemia

Iron overload is the primary cause of mortality and morbidity in thalassemia major despite advances in chelation therapy. We performed a pilot clinical trial to evaluate the safety and efficacy of combined therapy with deferasirox (DFX, 20-30 mg/kg daily) and deferoxamine (DFO, 35-50mg/kg on 3-7 days/week) in 22 patients with persistent iron overload or organ damage. In the 18 subjects completing 12 months of therapy, median liver iron concentration decreased by 31% from 17.4 mg/g (range 3.9-38.2mg/g) to 12.0mg/g (range 0.96-26.7 mg/g, p<0.001). Median ferritin decreased by 24% from 2465 ng/mL (range 1110-10,700 ng/mL) to 1875 ng/mL (range 421-5800 ng/mL, p=0.002). All 6 subjects with elevated myocardial iron showed improvement in MRI T2* (p=0.031). The mean±S.E. plasma non-transferrin-bound iron (NTBI) declined from 3.10±0.25μM to 2.15±0.29μM (p=0.028). The administration of DFX during infusion of DFO further lowered NTBI (-0.28±0.08 μM, p=0.004) and labile plasma iron (LPI, -0.03±0.01 μM, p=0.006). The simultaneous administration of DFO and DFX rapidly reduced systemic and myocardial iron, and provided an excellent control of the toxic labile plasma iron species without an increase in toxicity.

The iron chelator, deferasirox, as a novel strategy for cancer treatment: oral activity against human lung tumor xenografts and molecular mechanism of action

Deferasirox is an orally effective iron (Fe) chelator currently used for the treatment of iron-overload disease and has been implemented as an alternative to the gold standard chelator, desferrioxamine (DFO). Earlier studies demonstrated that DFO exhibits anticancer activity due to its ability to deplete cancer cells of iron. In this investigation, we examined the in vitro and in vivo activity of deferasirox against cells from human solid tumors. To date, there have been no studies to investigate the effect of deferasirox on these types of tumors in vivo. Deferasirox demonstrated similar activity at inhibiting proliferation of DMS-53 lung carcinoma and SK-N-MC neuroepithelioma cell lines compared with DFO. Furthermore, deferasirox was generally similar or slightly more effective than DFO at mobilizing cellular (59)Fe and inhibiting iron uptake from human transferrin depending on the cell type. However, deferasirox potently inhibited DMS-53 xenograft growth in nude mice when given by oral gavage, with no marked alterations in normal tissue histology. To understand the antitumor activity of deferasirox, we investigated its effect on the expression of molecules that play key roles in metastasis, cell cycle control, and apoptosis. We demonstrated that deferasirox increased expression of the metastasis suppressor protein N-myc downstream-regulated gene 1 and upregulated the cyclin-dependent kinase inhibitor p21(CIP1/WAF1) while decreasing cyclin D1 levels. Moreover, this agent increased the expression of apoptosis markers, including cleaved caspase-3 and cleaved poly(ADP-ribose) polymerase 1. Collectively, we demonstrate that deferasirox is an orally effective antitumor agent against solid tumors.

Australian guidelines for the assessment of iron overload and iron chelation in transfusion-dependent thalassaemia major, sickle cell disease and other congenital anaemias

Iron overload is the most important cause of mortality in patients with thalassaemia major. Iron chelation is therefore a critical issue in the management of these patients and others with transfusion-dependent haemoglobinopathies and congenital anaemias. In recent years, significant developments have been made in the assessment of iron overload, including the use of magnetic resonance imaging for measuring liver and cardiac iron. Advances in the modalities available for iron chelation, with the advent of oral iron chelators including deferiprone and deferasirox in addition to parenteral desferrioxamine, have expanded treatment options. A group of Australian haematologists has convened to formulate guidelines for managing iron overload on the basis of available evidence, and to describe best consensus practice as undertaken in major Australian Haemoglobinopathy units. The results of their discussions are described in this article, with the aim of providing guidance in the management of iron overload in these patients.

A pharmaco-economic evaluation of deferasirox for treating patients with iron overload caused by transfusion-dependent thalassemia in Taiwan

BACKGROUND/PURPOSE

The newly available iron chelator deferasirox (Exjade, Novartis) is expected to provide better long-term clinical outcomes and improved quality of life for patients with thalassemia than its predecessor, deferoxamine (Desferal, Novartis), because of its oral tablet form.

METHODS

We used the Markov model to estimate total additional lifetime costs and quality-adjusted life years (QALYs) gained with deferasirox versus deferoxamine in patients with transfusion-dependent thalassemia. Patients were assumed to be 2 years of age at initiation of chelation therapy. Clinical outcomes in terms of morbidity and mortality from associated complications and life expectancy for the study population were estimated using the databases of the Bureau of National Health Insurance and the Health and Vital Statistics of Taiwan. Treatment costs were based on analyses of health insurance claims for patients with transfusion-dependent thalassemia. Utilities in terms of quality of life were also included in the model. The incremental cost-utility ratio of deferasirox versus deferoxamine was defined by the ratio of the difference in expected lifetime costs to the difference in QALYs. One-way sensitivity analyses were performed to examine the robustness of the results to key assumptions.

RESULTS

Patients treated with deferasirox are expected to experience a lower incidence of associated complications and obtain 2.3 QALYs (discounted) at an additional lifetime cost of US$36,291 per patient (US$15,596 per QALY). Sensitivity analyses showed that the unit drug cost of deferasirox had the greatest impact on the incremental cost-utility ratio. In addition, the incremental cost-utility ratio will increase by delaying the starting age (2 years of age in our study) of chelation therapy.

CONCLUSION

Compared with infusional deferoxamine, oral deferasirox improved clinical outcomes and quality of life in terms of iron chelation in transfusion-dependent patients with thalassemia at a reasonable cost from a healthcare perspective.

Iron chelation therapy in the management of transfusion-related cardiac iron overload

Iron overload is one of the major causes of morbidity and death in patients undergoing chronic transfusion therapy. Furthermore, excessive iron accumulation in the heart may result in impaired left ventricular dysfunction. With accurate monitoring techniques and treatment regimens, progression of heart complications can be followed, and their natural history changed. Iron chelation therapy is the mainstay of prevention and reversal of myocardial iron overload. Despite recent appraisals of general chelating strategies, the management of iron chelation in chronically transfused patients with a focus on the heart has not been extensively assessed. New studies published in the past couple of years have provided important new data in this topic and therefore this review summarizes the major studies that examined the removal of iron from the heart with the iron chelators: deferoxamine, deferiprone, and deferasirox. Since chronically transfused patients and their cardiac clinical presentations vary widely, this review tries to identify--with each drug--the precise scenarios evaluated, linking patients' baseline characteristics, clinical setting, and drug intake and dosing. Ultimately, by stratifying patients according to their cardiac iron overload status and ventricular function, this review identifies possible approaches for the initial treatment and follow-up of transfusion-related cardiac iron overload.

Observational study comparing long-term safety and efficacy of Deferasirox with Desferrioxamine therapy in chelation-naïve children with transfusional iron overload

OBJECTIVES

An observational study was conducted to explore postmarketing safety and efficacy of Deferasirox (DFX) in comparison with conventional Desferrioxamine (DFO) in chelation-naïve children with transfusional iron overload.

METHODS

Transfusion-dependent children (aged ≤ 5 yr) who had serum ferritin above 1000 μg/L and had been prescribed either first-line DFX or DFO for at least 12 months to maintain serum ferritin between 500 and 1000 μg/L were included. Initial DFX dose was 20 mg/kg/d for 7 d a week, and DFO dose was 25-35 mg/kg/d subcutaneously, given for 5 d a week. Dose adjustments were based on serum ferritin changes and safety markers. The primary efficacy endpoint was change in serum ferritin from baseline. The effect of transfusional iron loading rate (ILR) and different doses of chelators on serum ferritin was also assessed.

RESULTS

A total of 111 patients were observed for a median of 2.29 yr on DFX (n = 71) and 2.75 yr on DFO (n = 40). Absolute change in serum ferritin from baseline to the last available observation was not significant with DFX (91 μg/L, P = 0.5) but significantly higher with DFO (385 μg/L, P < 0.005). ILR and DFX doses had a major impact on serum ferritin changes in DFX cohort. The height- and weight-standard deviation scores did not differ significantly in both cohorts during the study. Fluctuations in liver enzymes and non-progressive increase in serum creatinine were the most common adverse events (DFX; 9.8%, 18.0% and DFO; 5.0%, 7.5%, respectively).

CONCLUSION

DFX is well tolerable and at least as effective as DFO to maintain safe serum ferritin levels and normal growth progression in chelation-naïve children.

Minihepcidins are rationally designed small peptides that mimic hepcidin activity in mice and may be useful for the treatment of iron overload

Iron overload is the hallmark of hereditary hemochromatosis and a complication of iron-loading anemias such as β-thalassemia. Treatment can be burdensome and have significant side effects, and new therapeutic options are needed. Iron overload in hereditary hemochromatosis and β-thalassemia intermedia is caused by hepcidin deficiency. Although transgenic hepcidin replacement in mouse models of these diseases prevents iron overload or decreases its potential toxicity, natural hepcidin is prohibitively expensive for human application and has unfavorable pharmacologic properties. Here, we report the rational design of hepcidin agonists based on the mutagenesis of hepcidin and the hepcidin-binding region of ferroportin and computer modeling of their docking. We identified specific hydrophobic/aromatic residues required for hepcidin-ferroportin binding and obtained evidence in vitro that a thiol-disulfide interaction between ferroportin C326 and the hepcidin disulfide cage may stabilize binding. Guided by this model, we showed that 7–9 N-terminal amino acids of hepcidin, including a single thiol cysteine, comprised the minimal structure that retained hepcidin activity, as shown by the induction of ferroportin degradation in reporter cells. Further modifications to increase resistance to proteolysis and oral bioavailability yielded minihepcidins that, after parenteral or oral administration to mice, lowered serum iron levels comparably to those after parenteral native hepcidin. Moreover, liver iron concentrations were lower in mice chronically treated with minihepcidins than those in mice treated with solvent alone. Minihepcidins may be useful for the treatment of iron overload disorders.

Removal of cadmium by combining deferasirox and desferrioxamine chelators in rats

An investigation was conducted to evaluate the ability of two chelators, deferasirox and desferrioxamine (DFO), in removing cadmium from biological system. The potential efficiency of those chelators were investigated after cadmium administration for 60 days following two dose levels of 20 and 40 mg/kg body weight daily to male rats. However, abnormalities were observed in clinical signs after cadmium administration, such as yellowish discoloration of hair, flaccid and hypotonic muscles, irritability, weakness and loss of weight. The hypothesis that the two chelators might be more efficient as combined therapy than single therapy in removing metal ions from the body was considered. In this way, two known chelators, deferasirox and DFO were chosen and tested in the acute rat model. The chelation therapy results show that deferasirox and DFO are able ?to remove cadmium ions from the body, while iron concentration returned to the normal level and symptoms are decreased.

Serum ferritin levels, socio-demographic factors and desferrioxamine therapy in multi-transfused thalassemia major patients at a government tertiary care hospital of Karachi, Pakistan

Background

Beta thalassemia is the most frequent genetic disorder of haemoglobin synthesis in Pakistan. Recurrent transfusions lead to iron-overload manifested by increased serum Ferritin levels, for which chelation therapy is required.

Findings

The study was conducted in the Pediatric Emergency unit of Civil Hospital Karachi after ethical approval by the Institutional Review Board of Dow University of Health Sciences. Seventy nine cases of beta thalassemia major were included after a written consent. The care takers were interviewed for the socio-demographic variables and the use of Desferrioxamine therapy, after which a blood sample was drawn to assess the serum Ferritin level. SPSS 15.0 was employed for data entry and analysis.

Of the seventy-nine patients included in the study, 46 (58.2%) were males while 33 (41.8%) were females. The mean age was 10.8 (± 4.5) years with the dominant age group (46.2%) being 10 to 14 years. In 62 (78.8%) cases, the care taker education was below the tenth grade. The mean serum Ferritin level in our study were 4236.5 ng/ml and showed a directly proportional relationship with age. Desferrioxamine was used by patients in 46 (58.2%) cases with monthly house hold income significant factor to the use of therapy.

Conclusions

The mean serum Ferritin levels are approximately ten times higher than the normal recommended levels for normal individuals, with two-fifths of the patients not receiving iron chelation therapy at all. Use of iron chelation therapy and titrating the dose according to the need can significantly lower the iron load reducing the risk of iron-overload related complications leading to a better quality of life and improving survival in Pakistani beta thalassemia major patients.

Conflicts of Interest: None

Recent advances in β-thalassemias

β-thalassemias are heterogeneous hereditary anemias characterized by a reduced output of β-globin chains. The disease is most frequent in the temperate regions of the world, where it represents an important health problem. In the last decades, several programs, aimed at controlling the birth rate of thalassemia newborns by screening and prenatal diagnosis of populations with high risk of β-thalassemia, have been successful accomplished. Bone marrow transplantation has offered a definitive cure for the fraction of patients with available donors. In the same time, steady improvements were made in the traditional clinical management of β-thalassemia patients. The introduction of the oral iron chelators deferiprone that preferentially chelates hearth iron and the development of novel NMR diagnostic methods has led to reduced morbility, increased survival and improved quality of life. More recently, major advances have being made in the discovery of critical modifier genes, such as Myb and especially BCL11A (B cell lymphoma 11A), a master regulator of HbF (fetal hemoglobin) and hemoglobin switching. Polimorphysms of BCL11A, Myb and γ-globin genes account for most of the variability in the clinical phenotypes in β-thalassemia and sickle cell anemia patients. Finally, the year 2010 has brought in the first successful experiment of gene therapy in a β-thalassemia patient, opening up the perspective of a generalized cure for all β- thalassemia patients.

Update on iron chelators in thalassemia

Over the past four decades, there have been dramatic improvements in survival for patients with thalassemia major due in large measure to improved iron chelators. Two chelators are approved for use in the United States and Canada, parenteral deferoxamine and oral deferasirox. Three are available in much of the rest of the world, where oral deferiprone is also approved (in the United States, deferiprone is only available in studies, for emergency use, or on a "compassionate-use" basis). Many trials and worldwide clinical experience demonstrate that each of the three drugs can chelate and remove iron, and thereby prevent or improve transfusional hemosiderosis in thalassemia patients. However, the chelators differ strikingly in side-effect profile, cost, tolerability and ease of adherence, and (to some degree) efficacy for any specific patient. The entire field of chelator clinical trials suffers from the fact that each drug (as monotherapy or in combination) has not been tested directly against all of the other possibilities. Acknowledging the challenges of assessing chelators with diverse properties and imperfect comparative data, the purpose of this review is to summarize the last 4 years of studies that have improved our understanding of the applications and limitations of iron chelators in various settings for thalassemia patients, and to point out areas for much-needed future research.

Quercetin-iron chelates are transported via glucose transporters

Flavonoids are well-known antioxidants and free radical scavengers. Their metal-binding activity suggests that they could be effective protective agents in pathological conditions caused by both extracellular and intracellular oxidative stress linked to metal overload. Quercetin is both a permeant ligand via glucose transport proteins (GLUTs) and a high-affinity inhibitor of GLUT-mediated glucose transport. Chelatable "free iron" at micromolar concentrations in body fluids is a catalyst of hydroxyl radical (OH(•)) production from hydrogen peroxide. A number of flavonoids, e.g., quercetin, luteolin, chrysin, and 3,6-dihydroxyflavone, have been demonstrated to chelate intracellular iron and suppress OH(•) radical production in Madin Darby canine kidney cells. The most effective chelation comes from the flavonone B ring catechol found in both quercetin and luteolin. We show here that quercetin concentrations of <1μM can facilitate chelatable iron shuttling via GLUT1 in either direction across the cell membrane. These siderophoric effects are inhibited by raised quercetin concentrations (>1μM) or GLUT inhibitors, e.g., phloretin or cytochalasin B, and iron efflux is enhanced by impermeant extracellular iron chelators, either desferrioxamine or rutin. This iron shuttling property of quercetin might be usefully harnessed in chelotherapy of iron-overload conditions.

Clinical efficacy and safety evaluation of tailoring iron chelation practice in thalassaemia patients from Asia-Pacific: a subanalysis of the EPIC study of deferasirox

Although thalassaemia is highly prevalent in the Asia-Pacific region, clinical data on efficacy and safety profiles of deferasirox in patients from this region are rather limited. Recently, data from the multicentre Evaluation of Patients' Iron Chelation with Exjade (EPIC) study in 1744 patients with different anaemias has provided an opportunity to analyse 1115 thalassaemia patients, of whom 444 patients were from five countries in the Asia-Pacific region (AP) for whom thalassaemia management and choice of iron chelators were similar. Compared to the rest of the world (ROW), baseline clinical data showed that the AP group appeared to be more loaded with iron (3745.0 vs. 2822.0 ng/ml) and had a higher proportion on deferoxamine monotherapy prior to the study (82.9 vs. 58.9%). Using a starting deferasirox dose based on transfusional iron intake and tailoring it to individual patient response, clinical efficacy based on serum ferritin reduction in AP and ROW thalassaemia patients was similar. Interestingly, the AP group developed a higher incidence of drug-related skin rash compared to ROW (18.0 vs. 7.2%), which may indicate different pharmacogenetic backgrounds in the two populations. Our analysis confirms that, with appropriate adjustment of dose, deferasirox can be clinically effective across different regions, with manageable side effects.

In vitro inhibition of bacterial growth by iron chelators

The antimicrobial activity of the iron(III)-selective 3-hydroxypyridin-4-one chelators, CP251(1) and CP252(2), was evaluated in comparison with that of diethylenetriamine-penta acetic acid (3). CP251 was found to exhibit an inhibitory effect on the growth of both Gram-positive and Gram-negative bacteria. CP251 may find application in the treatment of external infections such as those associated with wounds.

Deferasirox for managing iron overload in people with myelodysplastic syndrome

BACKGROUND

The myelodysplastic syndrome (MDS) comprises a diverse group of haematopoietic stem cell disorders. Due to symptomatic anaemia most patients require supportive therapy including repeated red blood cell (RBC) transfusions. In combination with increased iron absorption, this contributes to the accumulation of iron resulting in secondary iron overload and the risk of organ dysfunction and reduced life expectancy. Since the human body has no natural means of getting rid of excess iron, iron chelation therapy is usually recommended. However, whether the new oral chelator deferasirox leads to relevant benefit is unclear.

OBJECTIVES

To assess the effectiveness and safety of oral deferasirox in people with myelodysplastic syndrome and iron overload.

SEARCH STRATEGY

We searched MEDLINE, EMBASE, The Cochrane Library, Biosis Previews, Web of Science, Derwent Drug File, XTOXLINE and three trial registries: Current Controlled Trials: www.controlled-trials.com, ClinicalTrials.gov: www.clinicaltrials.gov, ICTRP: www.who.int./ictrp/en/. Most recent searches of these databases: June 2010.

SELECTION CRITERIA

Randomised controlled trials comparing deferasirox with no therapy/placebo or with another iron chelating treatment schedule.

DATA COLLECTION AND ANALYSIS

No studies eligible for inclusion in this review were identified.

MAIN RESULTS

No studies were included in this review. However, we identified one ongoing study comparing deferasirox with deferoxamine.

AUTHORS' CONCLUSIONS

We planned to report evidence from randomised clinical trials evaluating the effectiveness of deferasirox compared to either placebo/no treatment or other chelating regimens such as deferoxamine in people with myelodysplastic syndrome. However, no completed randomised trials addressing this question could be identified.One ongoing randomised study comparing deferasirox with placebo was identified and preliminary data will hopefully be available soon. These results will be important to inform physicians and patients on the advantages and disadvantages of this treatment option.