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Precision Medicine in Transfusion-Dependent and Non-Transfusion-Dependent β-Thalassemia: Toward Personalized Diagnosis and Therapy.

β-thalassemia comprises a clinically heterogeneous group of disorders in which anemia severity, transfusion exposure, iron loading, and organ complications vary widely among individuals. This structured narrative review summarizes practical applications of precision medicine in transfusion-dependent thalassemia (TDT) and non-transfusion-dependent thalassemia (NTDT), with explicit attention to which strategies apply to each clinical category. Literature indexed in PubMed and Scopus from 2000 to 2025 was reviewed using terms related to thalassemia, precision medicine, magnetic resonance imaging (MRI), chelation tailoring, next-generation sequencing (NGS), fetal hemoglobin (HbF) modifiers, luspatercept, mitapivat, hepcidin, gene therapy, gene editing, and artificial intelligence (AI). Evidence was synthesized descriptively because interventions, outcomes, and populations were heterogeneous, and no pooled meta-analysis was performed. In TDT, precision care is centered on individualized transfusion planning, extended red-cell antigen matching, MRI-guided cardiac and hepatic iron monitoring, organ-directed chelation intensification, and selection of disease-modifying or curative approaches. In NTDT, precision care emphasizes accurate phenotype classification, MRI liver iron concentration, because serum ferritin may underestimate iron burden, selective chelation, surveillance for NTDT-specific complications, and individualized use of agents that improve anemia. Personalized chelation should include deferiprone, either alone or in combination, when cardiac iron is increased. Comprehensive molecular diagnosis should include HBB together with HBA1 and HBA2 assessment, while secondary and tertiary modifiers help explain phenotypic variability and complication risk. Hepcidin and growth differentiation factor 15 (GDF-15) are discussed as investigational biomarkers; transferrin saturation is not recommended for routine iron-overload assessment in thalassemia. AI currently has its strongest role in screening and diagnosis, whereas risk-stratification models remain exploratory. Equitable implementation requires standardized TDT/NTDT pathways, regional MRI and genomics access, longitudinal registries, and multidisciplinary interpretation.

Humans↗

Ferrophilic characteristics of Vibrio vulnificus and potential usefulness of iron chelation therapy.

We determined the ferrophilic characteristics of Vibrio vulnificus to evaluate the potential usefulness of iron chelation therapy for the prevention of V. vulnificus infection. Readily available non-transferrin-bound iron (NTBI) is required for the initiation of V. vulnificus growth under in vitro iron-limited conditions and human ex vivo conditions. NTBI aided efficient transferrin-bound iron (TBI) use by V. vulnificus, and the vulnibactin-mediated iron-uptake system was expressed after bacterial growth had been started by NTBI. V. vulnificus required higher NTBI levels for the initiation of growth, produced siderophores at lower levels, and used TBI less efficiently than other bacteria. In addition, the growth of V. vulnificus was inhibited by deferiprone, a clinically available iron chelator. These results show that V. vulnificus is a ferrophilic bacterium that requires higher NTBI levels than other pathogens and that iron chelation therapy might be an effective means of preventing the in vivo growth of V. vulnificus in susceptible patients.

Bacterial Proteins↗

Infection due to Yersinia enterocolitica in a series of patients with beta-thalassemia: incidence and predisposing factors.

Over 15 years, 14 patients with yersiniosis in two North American comprehensive thalassemia clinics (0.6 cases per 100 patient-years) presented with fever (100%), diarrhea (86%), right-lower-quadrant abdominal pain (71%), bacteremia (57%), a palpable abdominal mass (36%), and pharyngitis (28%). Clinically apparent infection occurred within 10 days of blood transfusion in 57% of patients. Nine patients (64%) had only a modest elevation in serum level of ferritin (< 2,000 micrograms/L). Patients with focal abdominal findings had a higher body iron burden, as estimated by the serum ferritin level, and significant intraabdominal suppurative complications. Two patients were not receiving iron-chelating therapy with deferoxamine; one patient was receiving the experimental chelator deferiprone (L1). Iron-loaded patients with beta-thalassemia are at greatly increased risk for severe yersiniosis, even when their body iron burden (as indicated by the serum ferritin level) is only moderately elevated and they are not receiving iron-chelating therapy with deferoxamine.

Adolescent↗

Iron chelation therapy.

Iron chelation therapy is essential to prevent death from cardiac toxicity in patients with thalassemia major or other severe refractory anemias who need regular blood transfusions. Iron chelating drugs also have potential for clinical use as antiproliferative agents in neoplastic diseases and to reduce free radical-induced tissue damage in rheumatoid arthritis, anthracycline-induced cardiotoxicity, and reperfusion injury. Experimental data and clinical trials also suggest they may have therapeutic value as adjuncts to antimalarial and anti-Pneumocystis carinii therapy and to reduce aluminum toxicity. There is therefore an urgent need for an orally active, inexpensive iron chelating drug, because desferrioxamine, the only currently widely available iron chelator, must be given parenterally and is expensive, making it unavailable for long-term use in many parts of the world. L1 (also known as deferiprone, 1-2 dimethyl-3-hydroxpyrid-4-one, DMHP, and CP20) has emerged as an orally active iron chelator with comparable efficiency to desferrioxamine in both short- and long-term clinical studies. Adverse side-effects, principally agranulocytosis and arthropathy, have raised doubts about its safety, and further trials are now planned to evaluate the incidence of these and other toxicities. Despite numerous studies, no other orally active agent has been shown in clinical trials to be as effective or as safe as L1.

Cardiomyopathies↗

Quantitative evaluation of oxidative stress status on peripheral blood in beta-thalassaemic patients by means of electron paramagnetic resonance spectroscopy.

High oxidative stress status (OSS) is known to be one of the most important factors determining cell injury and consequent organ damage in thalassaemic patients with secondary iron overload. Using an innovative hydroxylamine 'radical probe' capable of efficiently trapping majority of oxygen-radicals including superoxide we measured, by electron paramagnetic resonance (EPR) spectroscopy, OSS in peripheral blood of 38 thalassaemic patients compared with sex-/age-matched healthy controls. Thalassaemic patients showed sixfold higher EPR values of OSS than controls. Significantly higher EPR values of OSS were observed in those with a severe phenotype (thalassaemia major, transfusion-dependent) with respect to mild phenotype (sickle-cell/beta-thalassaemia, not transfusion-dependent) or thalassaemia intermedia. In patients with thalassaemia major, EPR values of OSS were positively correlated with serum ferritin and with alanine aminotransferase levels. In patients with sickle cell/beta-thalassaemia, there was no correlation between EPR value of OSS and all parameters considered. The type of chelating therapy (desferrioxamine or deferiprone) did not have an effect on EPR value of OSS. In conclusion, EPR 'radical probe' seems to be a valid innovative method to determine total OSS in patients affected by thalassaemia and might be used for evaluating new strategies of chelation, new chelators, or the efficacy of antioxidant formula.

Adult↗

Serum ferritin level as a predictor of impaired growth and puberty in thalassemia major patients.

OBJECTIVE: Previous studies suggested that in patients with thalassemia major, initiating deferoxamine (DFO) therapy before puberty can prevent iron-induced failure of growth and puberty. However, early initiation of chelation has also been associated with DFO toxicity. The aim of this retrospective study was to determine the prevalence rates of endocrine complications and DFO bone toxicity in our thalassemia major patients and to correlate them with the degree of iron chelation. METHODS: Thirty-nine patients with thalassemia major were followed for a median of 16.3 yr (range 2-28). Individual mean serum ferritin level during the study period was calculated using repeated annual measurements. Bone DFO toxicity was assessed by wrist and spine radiographs; endocrine dysfunction by anthropometric measurements and pubertal stage; and hypogonadotropic hypogonadism by lack of luteinizing hormone response to gonadotropin-releasing hormone. RESULTS: Chelation therapy was initiated at median age 4.9 yr. Mean serum ferritin level during the study period was 2698 +/- 1444 ng/mL. Hypogonadism was noted in 59% of the patients who reached pubertal age, and short stature was found in 36% of patients who reached final height. Mean ferritin level of 2500 ng/mL during puberty was the cut-off for hypogonadism, and ferritin level of 3000 ng/mL during prepuberty was the cut-off for final short stature. None of the patients who attained final height had signs of DFO bone toxicity. CONCLUSIONS: High serum ferritin levels during puberty are a risk factor for hypogonadism, and high serum ferritin levels during the first decade of life predict final short stature. It remains to be determined whether improving chelation by earlier initiation of DFO or by the combined use of DFO and deferiprone will lead to better growth and sexual development without DFO toxicity.

Adolescent↗

Iron primes hepatic macrophages for NF-kappaB activation in alcoholic liver injury.

NF-kappaB activation induced by lipopolysaccharide (LPS) in cultured hepatic macrophages (HM) may be abrogated by pretreatment of cells with a lipophilic iron chelator, 1,2-dimethyl-3-hydroxypyrid-4-one (L1, deferiprone), suggesting a role for iron in this molecular event [M. Lin, M., R. A. Rippe, O. Niemelä, G. Brittenham, and H. Tsukamoto, Am. J. Physiol. 272 (Gastrointest. Liver Physiol. 35): G1355-G1364, 1997]. To ascertain the relevance in vivo of this hypothesis, HM from an experimental model of alcoholic liver injury were examined for the relationship between nuclear factor (NF)-kappaB activation and iron storage. HM showed a significant increase in nonheme iron concentration (+70%), accompanied by enhanced generation of electron paramagnetic resonance-detected radicals (+200%), NF-kappaB activation (+100%), and tumor necrosis factor-alpha (+150%) and macrophage inflammatory protein-1 (+280%) mRNA induction. Treatment of the cells ex vivo with L1 normalized all these parameters. HM content of ferritin protein, ferritin L chain mRNA, and hemeoxygenase-1 mRNA and splenic content of nonheme iron were increased, suggesting enhanced heme turnover as a cause of the increased iron storage and NF-kappaB activation. To test this possibility, increased iron content in HM was reproduced in vitro by phagocytosis of heat-treated red blood cells. Treatment caused a 40% increase in nonheme iron concentration and accentuated LPS-induced NF-kappaB activation twofold. Both effects could be abolished by pretreatment of cells with zinc protoporphyrin, a hemeoxygenase inhibitor. To extend this observation, animals were splenectomized before 9-wk alcohol feeding. Splenectomy resulted in further increments in HM nonheme iron storage (+60%) and NF-kappaB activation (+90%) and mononuclear cell infiltration (+450%), particularly around the iron-loaded HM in alcohol-fed animals. These results support the pivotal role of heme-derived iron in priming HM for NF-kappaB activation and expression of proinflammatory genes in alcoholic liver injury.

Animals↗

Treatment of beta-thalassemia patients with recombinant human erythropoietin: effect on transfusion requirements and soluble adhesion molecules.

The most common single genetic disorder and a major public health issue in Greece and other Mediterranean countries is beta-thalassemia. Current therapeutic approaches for homozygous beta-thalassemia entail blood transfusions and iron chelation therapy with deferoxamine or deferiprone for preventing tissue hemosiderosis. Recently, much effort has focused on various inducers of fetal hemoglobin (HbF) such as recombinant human erythropoietin (rHuEPO), especially in beta-thalassemia intermedia. Ten adult patients, 5 with beta-thalassemia major and 5 with beta-thalassemia intermedia, received 150 IU/kg rHuEPO (epoetin-alpha) subcutaneously three times a week. Seven patients were transfused every 14-30 days and 3 with beta-thalassemia intermedia were only occasionally transfused. The minimum duration of treatment was 12 weeks in order to define if there was any response. Transfusion intervals were modified according to the rHuEPO response to maintain stable Hb values. Lower transfusion requirements were observed in 5 patients after rHuEPO treatment (p = 0.028). In the 3 non-transfused patients, Hb values increased, and the patients are still being treated and followed up for a period ranging from 14 weeks to 2 years. Two patients with thalassemia major discontinued treatment after 12 weeks, as they did not achieve any response regarding transfusion requirements or Hb values. Pretreatment serum transferrin receptor levels were higher than in controls (p < 0.001) and significantly increased following rHuEPO treatment (p = 0.027). Patients had higher serum endothelin-3, sICAM-1 and sE-selectin values before rHuEPO treatment compared to controls (p < 0.001, p < 0.001 and p = 0.016, respectively), but these values were not altered during treatment. HbF values presented a slight, non-significant increase. rHuEPO treatment has a beneficial effect in transfusion-dependent beta-thalassemia patients. Although a slight increase in HbF levels was observed, other possible mechanisms are probably involved. None of our patients experienced thrombotic complications and a rise in blood pressure.

Adolescent↗

Evaluation of new iron chelators for clinical use.

Evaluation of new chelators for clinical use is limited by the availability of models which will predict the therapeutic safety margin of chelators in iron-overloaded humans such as those with thalassaemia major. Animal models show significant differences with respect to the relative toxicity of different chelators compared with human. These differences can be ascribed to several factors: differences in iron metabolism between different species, human metabolism being significantly more conservative than in rodents or nonhuman primates; differences in drug metabolism between different species which are often difficult to predict from first principles, and difficulties in obtaining iron-overloaded models that are truly representative of transfusional iron overload clinically. These differences have been highlighted by clinical studies on hydroxypyridinone iron chelators such as 1,2-dimethyl-3-hydroxypyridin-4-one (L1, CP20, deferiprone) and 1,2-diethyl-3-hydroxypyridin-4-one (CP94). New tissue culture approaches towards understanding the mechanisms of neutropenia, cytostasis and apoptosis induced by chelators as well as the relative rates of inhibition of non-haem-iron-containing enzymes such as ribonucleotide reductase are predicted to identify chelators with a higher therapeutic safety margin.

Animals↗

Intracellular labile iron modulates adhesion of human monocytes to human endothelial cells.

OBJECTIVE: Elevated iron stores and high plasma iron concentration have been linked to an increased risk of atherosclerosis. Iron may thereby affect the interaction of monocytes to endothelium, an initial event in the formation of atherosclerotic plaques. METHODS AND RESULTS: Addition of 10 mumol/L non-transferrin-bound iron to the incubation medium caused a 2-fold increase in monocyte adhesion to human umbilical vein endothelial cells (HUVECs). A concordant increase in the expression of the following adhesion molecules was observed: vascular cell adhesion molecule-1, intercellular adhesion molecule-1, and endothelial selectin on HUVECs as well as very late antigen-4, and lymphocyte function-associated antigen-1 on monocytes. The inclusion of either deferiprone or salicylaldehyde isonicotinoylhydrazone counteracted these effects. Intracellular iron chelation by deferoxamine was completed only after 10 hours of incubation, shown by reversal of iron-quenched intracellular calcein signal, and concurrently the effects of iron were blunted. The membrane-impermeable chelator, diethylenetriamine pentaaceticacid, failed to negate iron effects, even after 48 hours of treatment. Furthermore, only membrane-permeable superoxide or hydroxyl radical scavengers were capable of preventing HUVEC activation by iron. CONCLUSIONS: Non-transferrin-bound iron increases the level of intracellular labile iron, which promotes monocyte recruitment to endothelium and may thereby contribute to the pathogenesis of atherosclerosis. Iron-induced adhesion molecule expression was observed, and this event may involve the production of oxygen radicals.

Cell Adhesion↗

Pulmonary dysfunction in transfusion-dependent patients with thalassemia major.

Pulmonary function tests were performed on 62 transfusion-dependent patients with thalassemia major, ranging in age from 8 to 33 years, and receiving chelation therapy with desferrioxamine or deferiprone. Percent predicted values for FVC, FEV1, and PEF were significantly reduced, whereas FEV1/FVC and maximal expiratory flow at 25% FVC were within normal limits, indicating a restrictive disease. Both FVC and FEV1 were negatively correlated with transfusional iron burden as indexed by age. Single-breath carbon monoxide transfer factor was reduced, even after correction for low hemoglobin concentration, and was negatively correlated with iron burden and iron overload, as indexed by serum ferritin levels. Owing to low hemoglobin concentration, blood-diffusing capacity was reduced, in spite of increased lung capillary blood volume, which was, however, adequate to normalize blood diffusing capacity when hemoglobin concentration was only partially restored by transfusion. The diffusing capacity of the alveolar-capillary membrane was substantially decreased and negatively correlated with age and serum ferritin, the fall being primarily attributed to increased membrane thickness. These findings suggest that lung fibrosis and/or interstitial edema related to iron overload are the main cause of pulmonary dysfunction observed in patients with thalassemia major.

Adolescent↗

Thalassemia.

New developments in the epidemiology, treatment and prognosis of thalassemia have dramatically altered the approach to the care of affected patients, and these developments are likely to have an even greater impact in the next few years. Demographic changes have required an awareness and understanding of the unique features of thalassemia disorders that were previously uncommon in North America but are now seen more frequently in children and recognized more consistently in adults. New methods for measuring tissue iron accumulation and new drugs to remove excessive iron are advancing two of the most challenging areas in the management of thalassemia as well as other transfusion-dependent disorders. Improved survival of patients with thalassemia has given new importance to adult complications such as endocrinopathies and hepatitis that have a major impact on the quality of life. This chapter describes how these changes are redefining the clinical management of thalassemia. In Section I, Dr. Renzo Galanello describes recent advances in iron chelation therapy. Several new chelators are either licensed in some countries, are in clinical trials or are in the late stages of preclinical development. Some of these iron chelators, such as deferiprone (DFP) and ICL670, are orally active. Others, such as hydroxybenzyl-ethylenediamine-diacetic acid (HBED) and starch deferoxamine, require parenteral administration but may be effective with less frequent administration than is currently required for deferoxamine. Chelation therapy employing two chelators offers the possibility of more effective removal of iron without compromising safety or compliance. Other strategies for chelation therapy may take advantage of the ability of particular chelators to remove iron from specific target organs such as the heart and the liver. In Section II, Dr. Dudley Pennell addresses cardiac iron overload, the most frequent cause of death from chronic transfusion therapy. The cardiac complications related to excessive iron may result from long-term iron deposition in vulnerable areas or may be due to the more immediate effects of nontransferrin-bound iron. Cardiac disease is reversible in some patients with intensive iron chelation therapy, but identification of cardiac problems prior to the onset of serious arrhythmias or congestive heart failure has proven difficult. New methods using magnetic resonance imaging (MRI) have recently been developed to assess cardiac iron loading, and studies suggest a clinically useful relationship between the results using these techniques and critical measures of cardiac function. Measurements such as T2* may help guide chelation therapy in individual patients and may also enhance the assessment of new chelators in clinical trials. The use of MRI-based technology also holds promise for wider application of non-invasive assessment of cardiac iron in the management of patients with thalassemia. In Section III, Dr. Melody Cunningham describes some of the important complications of thalassemia that are emerging as patients survive into adulthood. Hepatitis C infection is present in the majority of patients older than 25 years. However, antiviral therapy in patients with thalassemia has been held back by the absence of large clinical trials and concern about ribavirin-induced hemolysis. More aggressive approaches to the treatment of hepatitis C may be particularly valuable because of the additive risks for cirrhosis and hepatocellular carcinoma that are posed by infection and iron overload. Thrombosis is recognized with increasing frequency as a significant complication of thalassemia major and thalassemia intermedia, and pulmonary hypertension is now the focus of intense study. Risk factors for thrombosis such as splenectomy are being identified and new approaches to anticoagulation are being initiated. Pregnancies in women with thalassemia are increasingly common with and without hormonal therapy, and require a better understanding of the risks of iron overload and cardiac disease in the mother and exposure of the fetus to iron chelators. In Section IV, Dr. Elliott Vichinsky describes the dramatic changes in the epidemiology of thalassemia in North America. Hemoglobin E-beta thalassemia is seen with increasing frequency and poses a particular challenge because of the wide variability in clinical severity. Some affected patients may require little or no intervention, while others need chronic transfusion therapy and may be appropriate candidates for hematopoietic stem cell transplantation. Enhancers of fetal hemoglobin production may have a unique role in Hb E-beta thalassemia since a modest increase in hemoglobin level may confer substantial clinical benefits. Alpha thalassemia is also being recognized with increasing frequency in North America, and newborn screening for Hemoglobin Barts in some states is leading to early detection of Hb H disease and Hb H Constant Spring. New data clarify the importance of distinguishing these two disorders because of the increased severity associated with Hb H Constant Spring. The use of intrauterine transfusions to sustain the viability of fetuses with homozygous alpha thalassemia has created a new population of patients with severe thalassemia and has raised new and complex issues in genetic counseling for parents with alpha thalassemia trait.

Heart↗

Labile plasma iron in iron overload: redox activity and susceptibility to chelation.

Plasma non-transferrin-bound-iron (NTBI) is believed to be responsible for catalyzing the formation of reactive radicals in the circulation of iron overloaded subjects, resulting in accumulation of oxidation products. We assessed the redox active component of NTBI in the plasma of healthy and beta-thalassemic patients. The labile plasma iron (LPI) was determined with the fluorogenic dihydrorhodamine 123 by monitoring the generation of reactive radicals prompted by ascorbate but blocked by iron chelators. The assay was LPI specific since it was generated by physiologic concentrations of ascorbate, involved no sample manipulation, and was blocked by iron chelators that bind iron selectively. LPI, essentially absent from sera of healthy individuals, was present in those of beta-thalassemia patients at levels (1-16 microM) that correlated significantly with those of NTBI measured as mobilizer-dependent chelatable iron or desferrioxamine chelatable iron. Oral treatment of patients with deferiprone (L1) raised plasma NTBI due to iron mobilization but did not lead to LPI appearance, indicating that L1-chelated iron in plasma was not redox active. Moreover, oral L1 treatment eliminated LPI in patients. The approach enabled the assessment of LPI susceptibility to in vivo or in vitro chelation and the potential of LPI to cause tissue damage, as found in iron overload conditions.

Ascorbic Acid↗

Magnetic-field-induced DNA strand breaks in brain cells of the rat.

In previous research, we found that rats acutely (2 hr) exposed to a 60-Hz sinusoidal magnetic field at intensities of 0.1-0.5 millitesla (mT) showed increases in DNA single- and double-strand breaks in their brain cells. Further research showed that these effects could be blocked by pretreating the rats with the free radical scavengers melatonin and N-tert-butyl-alpha-phenylnitrone, suggesting the involvement of free radicals. In the present study, effects of magnetic field exposure on brain cell DNA in the rat were further investigated. Exposure to a 60-Hz magnetic field at 0.01 mT for 24 hr caused a significant increase in DNA single- and double-strand breaks. Prolonging the exposure to 48 hr caused a larger increase. This indicates that the effect is cumulative. In addition, treatment with Trolox (a vitamin E analog) or 7-nitroindazole (a nitric oxide synthase inhibitor) blocked magnetic-field-induced DNA strand breaks. These data further support a role of free radicals on the effects of magnetic fields. Treatment with the iron chelator deferiprone also blocked the effects of magnetic fields on brain cell DNA, suggesting the involvement of iron. Acute magnetic field exposure increased apoptosis and necrosis of brain cells in the rat. We hypothesize that exposure to a 60-Hz magnetic field initiates an iron-mediated process (e.g., the Fenton reaction) that increases free radical formation in brain cells, leading to DNA strand breaks and cell death. This hypothesis could have an important implication for the possible health effects associated with exposure to extremely low-frequency magnetic fields in the public and occupational environments.

Animals↗

Deferasirox: An effective once-daily orally active iron chelator.

Deferasirox (ICL670) in an orally absorbed tridentate chelator of iron (III), intended as a once-daily monotherapy for transfusional iron overload. Deferasirox was identified by Novartis from over 700 molecular entities in preclinical screening, comparing favorably with parenteral desferrioxamine or oral deferiprone. Clinical phase I and II studies demonstrated an exclusively fecal route of iron excretion, with a long plasma half-life, suitable for once-daily dosing and 24-hour protection from labile iron. Systematic large-scale prospective clinical trials have been completed in thalassemia major, sickle cell disease, and other transfusionally dependent anemias, such as myelodysplastic syndrome. These show dose-dependent reduction in body iron and have identified doses necessary either to stabilize or to decrease iron loading according to transfusion requirements. Tolerability after more than two years in phase III studies is good, with a low trial dropout rate and no drug-related arthropathy or agranulocytosis. An early, nonprogressive serum creatinine increase, remaining within normal ranges, was seen in about one-third of patients. Preliminary clinical findings using T2* as well as preclinical models suggest good drug access to myocardial iron. Deferasirox is currently registered as monotherapy for transfusional iron overload in more than 65 countries worldwide, including the United States and in the European Union.

Administration, Oral↗

The 10th International Conference on Oral Iron Chelators in the treatment of beta-thalassemia and other diseases and biomed meeting.

Development of oral iron (Fe) chelation therapy remains an important goal for the treatment of Fe-overload disease and perhaps other conditions. For many years, the major problem with Fe chelation therapy has been that the drug in clinical use. desferrioxamine (DFO), requires long sc. infusions (12-24 h day, 5-6 days per week). In addition, DFO is not orally effective, is highly expensive and does not easily permeate cell membranes to bind intracellular Fe pools. Obviously, the development of an orally effective and economical drug is vital. The recent 10th International Conference on Oral Iron Chelators (ICOC) discussed the latest findings in this challenging field. The conference was particularly focused to discuss recent investigations with the orally effective chelator, deferiprone (also) known as Li, DMHP or 1, 2-dimethylhydroxypyridone).

Administration, Oral↗

Iron chelator research: past, present, and future.

The occurrence of in vivo iron toxicity in the human body can be categorized into iron overload and non-iron overload conditions. Iron overload conditions are common in beta-thalassemia and hereditary hemochromatosis patients, and anthracycline mediated cardiotoxicity is an example of a non-iron overload condition in cancer patients, in which the toxicity is iron-dependent. While hundreds of iron chelators have been evaluated in animal studies, only a few have been studied in humans. Examples of iron chelator drugs are desferrioxamine (DFO), deferiprone (L1), and dexrazoxane (ICRF 187). The compound ICL670 has completed phase II clinical trials and a phase III trial is planned in 2003. Triapine is currently in phase II clinical trial as an anticancer agent. CP502, GT56-252, NaHBED, and MPB0201 are examples of new chelators in preclinical/clinical development. In the past decade, many new viable utilities for iron chelators have been reported. This includes the use of iron chelators as antiviral, photoprotective, antiproliferative, and antifibrotic agents. This review will focus on the status of drug development for the treatment of iron overload in patients with beta-thalassemia and the potential use of iron chelators in the prevention and treatment of other diseases.

Animals↗

Chelators as antidotes of metal toxicity: therapeutic and experimental aspects.

The effects of chelating drugs used clinically as antidotes to metal toxicity are reviewed. Human exposure to a number of metals such as lead, cadmium, mercury, manganese, aluminum, iron, copper, thallium, arsenic, chromium, nickel and platinum may lead to toxic effects, which are different for each metal. Similarly the pharmacokinetic data, clinical use and adverse effects of most of the chelating drugs used in human metal poisoning are also different for each chelating drug. The chelating drugs with worldwide application are dimercaprol (BAL), succimer (meso-DMSA), unithiol (DMPS), D-penicillamine (DPA), N-acetyl-D-penicillamine (NAPA), calcium disodium ethylenediaminetetraacetate (CaNa(2)EDTA), calcium trisodium or zinc trisodium diethylenetriaminepentaacetate (CaNa(3)DTPA, ZnNa(3)DTPA), deferoxamine (DFO), deferiprone (L1), triethylenetetraamine (trientine), N-acetylcysteine (NAC), and Prussian blue (PB). Several new synthetic homologues and experimental chelating agents have been designed and tested in vivo for their metal binding effects. These include three groups of synthetic chelators, namely the polyaminopolycarboxylic acids (EDTA and DTPA), the derivatives of BAL (DMPS, DMSA and mono- and dialkylesters of DMSA) and the carbodithioates. Many factors have been shown to affect the efficacy of the chelation treatment in metal poisoning. Within this context it has been shown in experiments using young and adult animals that metal toxicity and chelation effects could be influenced by age. These findings may have a bearing in the design of new therapeutic chelation protocols for metal toxicity.

Age Factors↗