Complications of beta-thalassemia major in North America

Iron chelation therapy: clinical effectiveness, economic burden and quality of life in patients with iron overload

INTRODUCTION

This study of UK patients examines clinical, health-related quality of life (HRQOL) and economic outcomes associated with iron chelation therapy (ICT). Desferrioxamine (DFO) (Desferal; Novartis, Switzerland) and Deferiprone (Ferriprox; Apotex, Canada) are ICTs used to treat iron overload. DFO requires 8-to 12-hour infusions a minimum of five times per week. Deferiprone is administered in an oral daily regimen. Although pharmacologically efficacious, clinical effectiveness of ICT within the real-world setting is yet to be fully elucidated.

METHODS

A naturalistic cohort study of 60 patients (beta-thalassaemia, n=40; sickle cell disease, n=14; myelodysplastic syndromes, n=6; 63% female) receiving ICT in four UK treatment centres was conducted. Serum ferritin level data were abstracted from medical charts. Compliance, HRQOL, satisfaction and resource utilisation data were collected from interviews. Maximum ICT costs were estimated using the resource utilisation data associated with DFO.

RESULTS

Mean serum ferritin levels, generally, remained elevated despite ICT. Compliance was suboptimal and HRQOL scores were lower than population norms. The total estimated mean weighted annual per-patient cost of DFO treatment was approximately pound19,000. DFO-related equipment, DFO drug, and home healthcare were estimated to account for 43%, 19% and 24% of costs, respectively. Other more minor components of total annual costs were for in-patient infusions, ICT home delivery services and monitoring costs.

CONCLUSION

Generally, patients are not achieving target serum ferritin thresholds despite chronic treatment for iron overload. ICT appears to negatively impact HRQOL; compliance with ICT is poor; and, in the case of DFO, treatment costs well exceed the cost of DFO alone. These results suggest that current ICT in the real-world setting is suboptimal with respect to various clinical, HRQOL and economic outcomes.

Oral iron chelators

Effective chelation therapy can prevent or reverse organ toxicity related to iron overload, yet cardiac complications and premature death continue to occur, largely related to difficulties with compliance in patients who receive parenteral therapy. The use of oral chelators may be able to overcome these difficulties and improve patient outcomes. A chelator's efficacy at cardiac and liver iron removal and side-effect profile should be considered when tailoring individual chelation regimens. Broader options for chelation therapy, including possible combination therapy, should improve clinical efficacy and enhance patient care.

Outcomes, utilization, and costs among thalassemia and sickle cell disease patients receiving deferoxamine therapy in the United States

Deferoxamine mesylate (DFO) reduces morbidity and mortality associated with transfusional iron overload. Data on the utilization and costs of care among U.S. patients receiving DFO in typical clinical practice are limited however. This was a retrospective study using a large U.S. health insurance claims database spanning 1/97-12/04 and representing 40 million members in >70 health plans. Study subjects (n = 145 total, 106 sickle cell disease [SCD], 39 thalassemia) included members with a diagnosis of thalassemia or SCD, one or more transfusions (whole blood or red blood cells), and one or more claims for DFO. Mean transfusion episodes were 12 per year. Estimated mean DFO use was 307 g/year. Central venous access devices were required by 20% of patients. Cardiac disease was observed in 16% of patients. Mean total medical costs were $59,233 per year including $10,899 for DFO and $8,722 for administration of chelation therapy. In multivariate analyses, potential complications of iron overload were associated with significantly higher medical care costs. In typical clinical practice, use of DFO in patients with thalassemia and SCD receiving transfusions is low. Administration costs represent a large proportion of the cost of chelation therapy. Potential complications of iron overload are associated with increased costs.

Update on thalassemia: clinical care and complications

beta-Thalassemia, originally named Cooley anemia, is an inherited blood disease. Various types of thalassemia are inherited anemias caused by mutations at the globin gene loci on chromosomes 16 and 11, affecting the production of alpha- or beta-globin protein, respectively. The combination of early diagnosis, improvements in monitoring for organ complications, and advances in supportive care have enabled many patients who have severe thalassemia syndromes to live productive, active lives well into adulthood.

Population analysis of the alpha hemoglobin stabilizing protein (AHSP) gene identifies sequence variants that alter expression and function

Alpha-hemoglobin stabilizing protein (AHSP) is a potential modifier of beta-thalassemia by virtue of its ability to detoxify excess free alpha-globin. However, examination of patients with beta-thalassemia from a few geographic regions failed to identify obvious AHSP mutations. We extended these studies by analyzing AHSP gene sequences in 366 anonymous individuals from five different areas of the world. We detected numerous polymorphisms comprising 18 different haplotypes and two rare missense mutations. Two sequence variations produce functional effects in laboratory assays. First, a rare missense mutation in a Brazilian/Mediterranean cohort converts asparagine to isoleucine at position 75 of AHSP protein and impairs its ability to inhibit reactive oxygen species production by alpha-hemoglobin. Second, a high-frequency polymorphism in intron 1 of the AHSP gene (12391 G>A) alters an Oct-1 transcription factor binding site previously shown to be important for optimal gene expression. The 12391A polymorphism impairs Oct-1 binding and inhibits the ability of AHSP regulatory sequences to activate expression of a linked luciferase reporter. Although structural mutations predicted to alter AHSP protein function or ablate its activity are rare, the 12391 G>A SNP is common and represents a potential mechanism through which genetically determined variations in AHSP expression could influence beta-thalassemia.

Characteristics of participants with self-reported hemochromatosis or iron overload at HEIRS study initial screening

There are few descriptions of young adults with self-reported hemochromatosis or iron overload (H/IO). We analyzed initial screening data in 7,343 HEmochromatosis and IRon Overload Screening (HEIRS) Study participants ages 25-29 years, including race/ethnicity and health information; transferrin saturation (TS) and ferritin (SF) measurements; and HFE C282Y and H63D genotypes. We used denaturing high-pressure liquid chromatography and sequencing to detect mutations in HJV, TFR2, HAMP, SLC40A1, and FTL. Fifty-one participants reported previous H/IO; 23 (45%) reported medical conditions associated with H/IO. Prevalences of reports of arthritis, diabetes, liver disease or liver cancer, heart failure, fertility problems or impotence, and blood relatives with H/IO were significantly greater in participants with previous H/IO reports than in those without. Only 7.8% of the 51 participants with previous H/IO reports had elevated TS; 13.7% had elevated SF. Only one participant had C282Y homozygosity. Three participants aged 25-29 years were heterozygous for potentially deleterious mutations in HFE2, TFR2, and HAMP promoter, respectively. Prevalences of self-reported conditions, screening iron phenotypes, and C282Y homozygosity were similar in 1,165 participants aged 30 years or greater who reported previous H/IO. We conclude that persons who report previous H/IO diagnoses in screening programs are unlikely to have H/IO phenotypes or genotypes. Previous H/IO reports in some participants could be explained by treatment that induced iron depletion before initial screening, misdiagnosis, or participant misunderstanding of their physician or the initial screening questionnaire.

Liquid chromatography-mass spectrometric assay for quantitation of the short-chain fatty acid, 2,2-dimethylbutyrate (NSC 741804), in rat plasma

2,2-Dimethylbutyrate (DMB) is a potential treatment for thalassemia and hemoglobinopathies. To facilitate pharmacokinetic evaluation of DMB, we developed an LC-MS assay and quantitated DMB in plasma of rats after an oral dose of 500mg/kg. After acetonitrile protein precipitation, DMB and dimethylvaleric acid (DMV) internal standard were derivatized to benzylamides, chromatographed on a Hydro-RP column with acetonitrile, water, and 0.1% formic acid, and detected by electrospray positive-mode ionization mass spectrometry. The assay was accurate (97-107%) and precise (3.4-6.2%) between 100 and 10,000ng/mL. Recovery from plasma was >62%. Plasma freeze-thaw and room temperature stability were acceptable.

Endothelial dysfunction and oxidant status in pediatric patients with hemoglobin E-beta thalassemia

Thalassemia major is characterized by anemia, iron overload, and oxidant damage to major organs, especially the cardiovascular system. Oxidative stress is ultimately involved in endothelial dysfunction, a condition which is evident in adults suffering from various cardiovascular diseases including thalassemia. We investigated endothelial function in pediatric patients with hemoglobin E-beta thalassemia (HbE-beta thalassemia), who have been exposed to excessive iron and oxidative stress for much shorter period than adults with thalassemia. We recruited 22 blood transfusion-dependent HbE-beta thalassemia patients aged 11.8 +/- 2.9 years and 20 healthy controls aged 12.1 +/- 1.7 years. Oxidant status was determined, and endothelial function was assessed by a forearm blood flow technique. Oxidative stress was increased in the thalassemic patients, as blood glutathione (GSH) and ratios of reduced GSH to GSH disulfide were markedly reduced, and superoxide anion released from blood cells was highly elevated. Oxidative stress response, assessed by gamma-glutamylcysteine ligase activity, was increased approximately twofold in thalassemia patients. Basal forearm blood flow was significantly increased in patients compared with controls (7.3 +/- 1.8 vs 6.0 +/- 1.8 ml/100 ml tissue/min, respectively), whereas forearm vasodilatory response to reactive hyperemia was depressed by 50% in patients compared with controls. Endothelial function is impaired in young thalassemia patients, and impaired endothelial function is associated with oxidant stress.

Platelet aggregation and activation in thalassemia major patients in Indonesia

Thromboembolic events and hypercoagulable state have been reported in patients with thalassemia. As platelets play an important role in the pathogenesis of thrombosis, the authors aimed to find the pattern of changes in platelet count, function and activation, and evidence of coagulation activation in patients with thalassemia major in Indonesia. A total of 31 patients with splenectomized and 35 patients with nonsplenectomized thalassemia major were enrolled in this study. Platelet count, platelet aggregation, beta-thromboglobulin, and D-dimer levels were measured. All measured parameters were significantly higher in splenectomized than in nonsplenectomized patients. beta-thromboglobulin level was increased, but D-dimer level was within normal range. The authors concluded that there was an increase in platelet activation in patients with beta-thalassemia major. Platelet activation was higher in splenectomized than in nonsplenectomized patients.

The heart in transfusion dependent homozygous thalassaemia today--prediction, prevention and management

Cardiac disease remains the major cause of death in thalassaemia major. This review deals with the mechanisms involved in heart failure development, the peculiar clinical presentation of congestive heart failure and provides guidelines for diagnosis and management of the acute phase of cardiac failure. It emphasizes the need for intensive medical – cardiac care and aggressive iron chelating management as, with such approaches, today, the patients outcomes can be favourable in the long term. It covers advances in the assessment of cardiac iron overload with the use of magnetic resonance imaging and makes recommendations for preventing the onset of cardiac problems by tailoring iron chelation therapy appropriate to the degree of cardiac iron loading found.

Consequences and costs of noncompliance with iron chelation therapy in patients with transfusion-dependent thalassemia: a literature review

BACKGROUND

Patients with thalassemia major require iron chelation therapy (ICT) to prevent complications from transfusional iron overload. Deferoxamine is effective, but requires administration as a slow continuous subcutaneous or intravenous infusion five to seven times per week. Deferiprone is a three-times-daily oral iron chelator, but has limited availability in the United States. Deferasirox is a once-daily oral iron chelator that was approved in the United States in 2005 for patients older than 2 years of age with transfusional iron overload.

STUDY DESIGN AND METHODS

Published evidence on rates of compliance with ICT and the association between compliance, and the incidence and costs of complications of iron overload, in patients with thalassemia major was reviewed.

RESULTS

A total of 18 studies were identified reporting data on compliance with ICT, including 7 that examined deferoxamine only, 6 that examined deferiprone only, and 5 that compared deferoxamine and deferiprone; no studies reporting compliance with deferasirox were identified. In studies of deferoxamine only, estimated mean compliance ranged from 59 to 78 percent. Studies of deferiprone generally reported better compliance, ranging from 79 to 98 percent. Results of comparative studies of deferoxamine and deferiprone suggest that compliance may be better with oral therapy. Numerous studies demonstrate that that poor compliance with ICT results in increased risk of cardiac disease and endocrinopathies, as well as lower survival. Although data on the costs of noncompliance are limited, a recent model-based study estimated the lifetime costs of inadequate compliance with deferoxamine to be $33,142.

CONCLUSIONS

Inadequate compliance with ICT in thalassemia major is common and results in substantial morbidity and mortality, as well as increased costs.

Clinical and economic burden of infused iron chelation therapy in the United States

BACKGROUND

Patients requiring chronic blood transfusions are at risk for iron overload, which, if not treated by iron chelation therapy (ICT), can create serious organ damage and reduce life expectancy. Current ICT requires burdensome 8- to 12-hour infusions five to seven times per week.

STUDY DESIGN AND METHODS

A naturalistic study of the burden of infused ICT was conducted in four US centers. Data from the initial and most recent years of ICT were collected from medical charts of consenting thalassemia (n = 40) and sickle cell disease (n = 9) patients. Quality of life (QoL), treatment satisfaction, and ICT-related resource utilization data were also collected from a patient interview.

RESULTS

Mean serum ferritin levels during the initial (2519 +/- 1382 ng/mL) and most recent (2741 +/- 2532 ng/mL) years remained unacceptably high and increased over time (306 +/- 2200 ng/mL; mean of 20+/- years of therapy). Within 30 days before interview, 55 percent of patients suffered at least one ICT-related adverse event; 76 percent missed at least one dose. QoL, measured by the SF-36, and treatment satisfaction appear compromised in this cohort. Although total annual costs of ICT were estimated at USD $30,000 to $35,000, drug accounted for only 50 to 60 percent of this amount.

CONCLUSIONS

Infused ICT may not provide adequate effectiveness in the real world. High ferritin levels seem to be associated with ICT noncompliance, likely in relation to the bothersome mode of administration and side effects. The total cost of ICT appears to well exceed that of drug alone.

Prospective evaluation of patient-reported outcomes during treatment with deferasirox or deferoxamine for iron overload in patients with beta-thalassemia

BACKGROUND

Iron chelation therapy (ICT) with deferoxamine (DFO), the current standard for the treatment of iron overload in patients with transfusion-dependent disorders such as beta-thalassemia, requires regular subcutaneous or intravenous infusions. This can lead to reduced quality of life and poor adherence, resulting in increased morbidity and mortality in iron-overloaded patients with beta-thalassemia. Deferasirox is an orally administered iron chelator that has been approved for use in the United States, Switzerland, and other countries.

OBJECTIVE

This analysis was conducted to compare patient-reported outcomes (PROs) during receipt of DFO infusions or once-daily oral therapy with deferasirox (ICL670).

METHODS

PROs were prospectively evaluated as part of a randomized, Phase III study comparing the efficacy and safety profile of DFO 20 to 60 mg/kg per day with those of deferasirox 5 to 30 mg/kg per day in patients (age > or =2 years) with beta-thalassemia who were receiving regular transfusions and had a liver iron concentration of > or =2 mg/g dry weight. PRO questionnaires were completed by patients or a parent or legal guardian at baseline, week 4, week 24, and end of study (EOS). Patients assessed their level of satisfaction with study treatment (very satisfied, satisfied, neutral, dissatisfied, or very dissatisfied) and rated its convenience (very convenient, convenient, neutral, inconvenient, or very inconvenient). Time lost from normal activities due to ICT in the previous 4 weeks was recorded using a single global assessment. At week 4, patients who had previous experience with DFO were asked to indicate their preference for treatment (ICT received before the study, ICT received during the study, no preference, or no response) and the reason for that preference. At EOS, all patients were asked if they would be willing to continue using the ICT they had received during the study. All study analyses were performed in all patients who received at least 1 dose of study medication.

RESULTS

Five hundred eighty-six patients (304 females, 282 males; age range, 2-53 years) received treatment with DFO (n = 290) or deferasirox (n = 296). Significantly more patients treated with deferasirox reported being very satisfied or satisfied with treatment compared with those treated with DFO (week 4: 92.0% vs 50.4%, respectively; week 24: 89.6% vs 44.0%; EOS: 85.1% vs 38.7%; all, P < 0.001). At the same time points, the majority of those treated with deferasirox reported that treatment was very convenient or convenient compared with those treated with DFO (95.5% vs 21.3%, 91.7% vs 17.4%, and 92.7% vs 11.3%, respectively; all, P < 0.001). Among patients who had previously taken DFO and were randomized to receive deferasirox during the study, 96.9% reported a preference for deferasirox over DFO. At EOS, the proportion of patients indicating a willingness to continue study therapy was significantly greater in those receiving deferasirox than in those receiving DFO (85.8% vs 13.8%; P < 0.001).

CONCLUSIONS

In this study, patient-reported satisfaction and convenience were significantly higher for the once-daily, oral ICT deferasirox than for DFO infusions. Among patients who had received DFO before the study, the majority indicated a preference for deferasirox over DFO. Most patients receiving deferasirox indicated that they would be willing to continue taking it. These results suggest that deferasirox had a positive impact on patients' daily lives.

The epidemiology of transfusion-associated hepatitis C in a children's hospital

BACKGROUND

Children transfused with blood and blood products before 1992 are at risk for chronic hepatitis C virus (HCV) infection. To determine the prevalence of HCV infection and risks associated with acquisition of HCV, a single-institution lookback study was performed.

STUDY DESIGN AND METHODS

A total of 5473 infants and children who received transfusions between 1982 and 1992 were identified. A control population of 600 age-, sex-, race- and zip code-matched children who did not receive transfusions with the same exclusions provided background seroprevalence data. Patients were tested for antibodies to HCV, confirmed with second generation recombinant immunoblot assay (RIBA) and when appropriate quantitative and qualitative HCV RNA by reverse transcription polymerase chain reaction (PCR). Viral persistence was assessed by serial PCR determinations for HCV RNA.

RESULTS

Of the 5473 eligible patients, 4726 were locatable and 2758 were tested. Forty-three children (1.6%) were persistently anti-HCV enzyme immunoassay (EIA)-positive, confirmed by RIBA; 39 were positive for the presence of HCV RNA. Four cleared their virus as assessed by two negative HCV PCRs 6 months apart. There was a borderline higher number of children with HCV who received fresh whole blood than those who tested HCV-negative.

CONCLUSION

Because HCV infection is generally asymptomatic, children are not identified unless they are specifically tested. We identified, enrolled, tested, and confirmed a new diagnosis of HCV infection in 43 patients. As HCV treatments become increasingly effective, it is important to identify silently infected individuals, particularly when the infection was iatrogenically induced.

Light and shadows in the iron chelation treatment of haematological diseases

This review outlines the main chelator groups studied to date, and the evidence for their clinical effectiveness. For each treatment, the strength of evidence was documented according to the guidelines from the American College of Cardiology and the American Heart Association. Three main haematological diseases were considered as models: thalassaemia major, sickle-cell disorders and myelodysplasia. Although the data in the literature do not allow firmly evidence-based conclusions, the findings suggest that in thalassaemia major: (i) deferoxamine remains the drug of choice for chelation treatment; (ii) if there is deferoxamine intolerance or a change of treatment is suggested, the options are deferiprone or, if the liver iron concentration is high, deferasirox treatment; and (iii) if the ferritin level is >2500 microg/l and liver iron concentation is >7 mg/g/dry weight, continuous subcutaneous (s.c.) or intravenous (i.v.) deferoxamine, or combined treatment with deferiprone and deferoxamine is advised. In case of heart failure, there is currently more solid documentation to support continuous s.c. or i.v. deferoxamine treatment than combined treatment with deferiprone and deferoxamine. However, more recent data in the literature suggest that the latter could be a satisfactory alternative. Finally, if iron chelation is required for sickle-cell disorders or myelodysplastic syndromes, the current data support the use of deferoxamine treatment.

Cardiac assessment of patients for haematopoietic stem cell transplantation

The expanding role of haematopoietic stem-cell transplantation (HSCT) renders the previous policy of avoiding transplantation in high-risk cardiac patients obsolete. Patients with amyloid, autoimmune conditions, sickle-cell disease, or thalassaemia, and patients over the age of 60 years are increasingly being offered HSCT. It is evident that the policy of avoiding transplantation in patients with impaired systolic function fails to identify all high-risk patients in such groups, and will deprive some patients of the benefits of HSCT unnecessarily. The development of an appropriate algorithm for cardiac pre-assessment and peri-transplant management is hampered by an inadequate understanding of the predictive value of various tests of cardiovascular function, the rapid evolution of advanced management strategies for cardiac dysfunction, and the development of non-cardiotoxic conditioning regimens. To meet this need we propose that an algorithm based on evidence from other clinical situations - already been found to be successful in the management of HSCT in patients with systemic sclerosis - should be used uniformly, and registry studies should be undertaken to distinguish those aspects of the algorithm that positively help to expand the remit of HSCT from those that add little of value.

The thalassaemia syndromes

The thalassaemia syndromes, endemic in the Mediterranean area, the Middle East, the Indian subcontinent, the Far East and in tropical Africa, are the most common hereditary disorders in humans, and millions of people are affected by diseases. Due to a widespread population flow between continents in recent past centuries, the thalassaemias are now occurring with relatively high frequency in many non-endemic areas. In the Nordic countries, homozygous thalassaemia is still relatively rare, and most health-care personnel are not familiar with these diseases. This article focuses on two important issues, namely the biological and the clinical aspects of thalassaemia.

Lumbar nerve root compression due to extramedullary hemopoiesis in a patient with thalassemia: complete clinical regression with radiation therapy. Case report and review of the literature

The authors describe the case of a 24-year-old woman who had a history of beta3-thalassemia and presented with severe symptoms of lumbar nerve root compression due to extramedullary hemopoiesis in the intervertebral foramen. Radiation therapy (2000 cGy in six fractions) was delivered to the mass. The patient's neurological symptoms completely resolved following treatment. Follow-up images showed a reduction in lesion size. The results of this unique case supported by a review of the literature suggest that radiation therapy alone is an effective modality in the treatment of patients with compression of neural structures due to extramedullary hemopoietic tissue.

Growth hormone reserve in adult beta thalassemia patients

Reduced serum insulin-like growth factor-1 (IGF-1) and hypogonadotrophic hypogonadism are common features of adult beta-thalassemia, and warrant evaluation of the growth hormone (GH)-IGF-1 axis. The aim of this study was to determine GH reserve in beta-thalassemia patients (9 females, 7 males, 15 major, 1 intermedia), age 29.3 +/- 6.9 years, BMI 21.3 +/- 1.9 kg/m2, and in 20 age, sex and BMI-matched healthy controls, using the GH-releasing hormone (GHRH)-arginine test. The associations between peak GH response and hormonal and biochemical indices were evaluated. Using BMI-related cut-off limits for peak GH response in the GHRH-arginine test, 4/16 beta-thalassemia patients had peak GH lower than 11.5 microg/l, the cut-off limit suggested for lean subjects, and were diagnosed as GH deficient (GHD). Using 9 microg/l as the cut-off limit 2/16 patients were GHD. Reduced serum IGF-1 and IGFBP-3 were present in 69% and 19% of the patients, respectively. Peak GH did not correlate with serum IGF-1, TSH, and fT4 levels or gonadal status. Neither peak GH nor IGF-1 correlated with serum ferritin. Our findings suggest that GHD is present in up to a quarter of adult beta-thalassemia patients. The clinical benefits of GH therapy need to be determined. GHD alone does not account for the high prevalence of reduced IGF-1 in adult beta-thalassemia.

Modification of CYP2E1 and CYP3A4 activities in haemoglobin E-beta thalassemia patients

OBJECTIVE

Thalassemia disease is a genetic haemoglobinopathy usually associated with an iron overload and some degree of organ impairment. The impact of the disease on the drug metabolising enzyme cytochrome P450 (CYP) is not known. CYP2E1 and CYP3A4 are responsible for the metabolism of a large number of drugs and changes in their activities may have clinical consequences.

METHODS

Haemoglobin E-beta thalassemia paediatric, blood transfusion-dependent patients apparently without complications (n = 35) and healthy controls (n = 42) were recruited in this study. The ratios of plasma 6-hydroxychlorzoxazone to chlorzoxazone, and urinary 6-beta-hydroxycortisol (6beta-OHF) to cortisol were used as indices for CYP2E1 and CYP3A4 activities, respectively. Blood and plasma samples were assayed for parameters of clinical biochemistry, oxidants and antioxidants.

RESULTS

There were significant increases in serum iron, protein carbonyl and lipid peroxidation in thalassemia patients, whereas there was a decrease in blood glutathione, but unchanged plasma nitric oxide metabolites. CYP2E1 activity in the patients was unchanged; however, when the patients were stratified by splenectomy status, CYP2E1 activity was increased in non-splenectomised patients in comparison with the controls and splenectomised subjects. On the other hand, 6beta-OHF/cortisol ratios increased markedly in patients associated with depressed growth hormone levels. There were no correlations between CYP2E1 activity and oxidant stress or antioxidant parameters.

CONCLUSIONS

This report is the first demonstration that thalassemia major is associated with an alteration of CYP2E1 and CYP3A4 activities; this could modify the sensitivity of thalassemia patients to the toxic or therapeutic effects of drugs.

Urinary hepcidin in congenital chronic anemias

BACKGROUND

Hepcidin, a regulator for iron homeostasis, is induced by inflammation and iron burden and suppressed by anemia and hypoxia. This study was conducted to determine the hepcidin levels in patients with congenital chronic anemias.

PROCEDURE

Forty-nine subjects with anemia, varying degrees of erythropoiesis and iron burden were recruited. Eight children with immune thrombocytopenia were included as approximate age-matched controls. Routine hematologic labs and urinary hepcidin (uhepcidin) levels were assessed. For thalassemia major (TM) patients, uhepcidin was obtained pre- and post-transfusion.

RESULTS

In TM, uhepcidin levels increased significantly after transfusion, demonstrated wide variance, and the median did not significantly differ from controls or thalassemia intermedia (TI). In both thalassemia syndromes, the hepcidin to ferritin ratio, a marker of the appropriateness of hepcidin expression relative to the degree of iron burden, was low compared to controls. In TI and sickle cell anemia (SCA), median uhepcidin was low compared to controls, P = 0.013 and <0.001, respectively. In thalassemia subjects, uhepcidin levels were positively associated with ferritin. In subjects with SCA, uhepcidin demonstrated a negative correlation with reticulocyte count.

CONCLUSIONS

This study examines hepcidin levels in congenital anemias. In SCA, hepcidin was suppressed and inversely associated with erythropoietic drive. In thalassemic syndromes, hepcidin was suppressed relative to the degree of iron burden. Transfusion led to increased uhepcidin. In thalassemia, the relative influence of known hepcidin modifiers was more difficult to assess. In thalassemic syndromes where iron overload and anemia have opposing effects, the increased erythropoietic drive may positively influence hepcidin production.

Cost effectiveness of once-daily oral chelation therapy with deferasirox versus infusional deferoxamine in transfusion-dependent thalassaemia patients: US healthcare system perspective

BACKGROUND

Deferasirox is a recently approved once-daily oral iron chelator that has been shown to reduce liver iron concentrations and serum ferritin levels to a similar extent as infusional deferoxamine.

OBJECTIVE

To determine the cost effectiveness of deferasirox versus deferoxamine in patients with beta-thalassaemia major from a US healthcare system perspective.

METHODS

A Markov model was used to estimate the total additional lifetime costs and QALYs gained with deferasirox versus deferoxamine in patients with beta-thalassaemia major and chronic iron overload from blood transfusions. Patients were assumed to be 3 years of age at initiation of chelation therapy and to receive prescribed dosages of deferasirox and deferoxamine that have been shown to be similarly effective in such patients. Compliance with chelation therapy and probabilities of iron overload-related cardiac disease and death by degree of compliance were estimated using data from published studies. Costs ($US, year 2006 values) of deferoxamine administration and iron overload-related cardiac disease were based on analyses of health insurance claims of transfusion-dependent thalassaemia patients. Utilities were based on a study of patient preferences for oral versus infusional chelation therapy, as well as published literature. Probabilistic and deterministic sensitivity analyses were employed to examine the robustness of the results to key assumptions.

RESULTS

Deferasirox resulted in a gain of 4.5 QALYs per patient at an additional expected lifetime cost of $US126,018 per patient; the cost per QALY gained was $US28,255. The cost effectiveness of deferasirox versus deferoxamine was sensitive to the estimated costs of deferoxamine administration and the quality-of-life benefit associated with oral versus infusional therapy. Cost effectiveness was also relatively sensitive to the equivalent daily dose of deferasirox, and the unit costs of deferasirox and deferoxamine, and was more favourable in younger patients.

CONCLUSION

Results of this analysis of the cost effectiveness of oral deferasirox versus infusional deferoxamine suggest that deferasirox is a cost effective iron chelator from a US healthcare perspective.

Clinical hemoglobinopathies: iron, lungs and new blood

PURPOSE OF REVIEW

Sickle cell disease and beta-thalassemia major are clinically significant hereditary anemias that elicit worldwide attention due to the frequency and severity of these disorders. Historically, most children who inherited these disorders died in the first decade of life. Recently, however, supportive care has extended lifespan through the fifth decade of life and beyond, with survival through early adulthood now indistinguishable from those unaffected by these disorders. As a result, chronic health impairments that significantly reduce the quality of life such as pulmonary hypertension and the consequences of transfusional iron overload have become principal challenges.

RECENT FINDINGS

We focus on important recent advances that are very likely to alter the nature of supportive care of these disorders or make it possible to identify prospectively high-risk patients who might benefit from novel therapies or even curative treatment in the form of hematopoietic cell transplantation. The availability of the latter, traditionally constrained by the requirement of a human leukocyte antigen-identical sibling donor, is very likely to be broadened as results after unrelated donor hematopoietic cell transplantation improve.

SUMMARY

In this review, several areas that are very likely to have a significant impact in the management of patients who inherit these disorders are discussed.

Increased prevalence of iron-overload associated endocrinopathy in thalassaemia versus sickle-cell disease

Iron-overload associated endocrinopathy is the most frequently reported complication of chronic transfusion therapy in patients with thalassaemia (Thal). This study compared iron-overloaded subjects with Thal (n = 142; 54%M; age 25.8 +/- 8.1 years) and transfused sickle-cell disease (Tx-SCD; n = 199; 43%M, 24.9 +/- 13.2 years) to non-transfused SCD subjects (non-Tx-SCD; n = 64, 50%M, 25.3 +/- 11.3 years), to explore whether the underlying haemoglobinopathy influences the development of endocrinopathy. Subjects were recruited from 31 centres in the USA, Canada and the UK. Subjects with Thal had more evidence of diabetes (13% vs. 2%, P < 0.001), hypogonadism (40% vs. 4%, P < 0.001), hypothyroidism (10% vs. 2%, P = <0.001) and growth failure (33% vs. 7%, P < 0.001), versus Tx-SCD. Fifty-six per cent of Thal had more than one endocrinopathy compared with only 13% of Tx-SCD (P < 0.001). In contrast, Tx-SCD was not different from non-Tx-SCD. Multivariate analysis indicated that endocrinopathy was more likely in Thal than SCD [Odds Ratio (OR) = 9.4, P < 0.001], with duration of chronic transfusion a significant predictor (OR = 1.4 per 10 years of transfusion, P = 0.04). Despite iron overload, endocrinopathy was not increased in Tx-SCD versus non-Tx-SCD, suggesting that the underlying disease may modulate iron-related endocrine injury. However, because transfusion duration remained a significant predictor of endocrinopathy, these data should be confirmed in SCD subjects that have been chronically transfused for longer periods of time.

Oxidative stress and inflammation in iron-overloaded patients with beta-thalassaemia or sickle cell disease

Blood transfusion therapy is life-saving for patients with beta-thalassaemia and sickle cell disease (SCD), but often results in severe iron overload. This pilot study examined whether the biomarkers of tissue injury or inflammation differ in these two diseases. Plasma malondialdehyde (MDA) was significantly increased 1.8-fold in thalassaemia relative to control patients. In contrast, MDA in SCD was not significantly different from controls. In multivariate analysis, the strongest predictors of elevated MDA were liver iron concentration (P < 0.001) and specific diagnosis (P = 0.019). A significant 2-fold elevation of non-transferrin bound iron (NTBI) was observed in thalassaemia relative to SCD. NTBI was not a significant predictor of high MDA in multivariate analysis. SCD patients showed a significant 2.2-fold elevation of the inflammatory marker interleukin (IL)-6 relative to controls, and a 3.6- and 1.7-fold increase in IL-5 and IL-10 relative to thalassaemia. Although alpha-tocopherol was significantly decreased by at least 32% in both thalassaemia and SCD, indicating ongoing oxidant stress and antioxidant consumption, gamma-tocopherol, a nitric oxide-selective antioxidant, was increased 36% in SCD relative to thalassaemia. These results demonstrate that thalassaemia patients have increased MDA and circulating NTBI relative to SCD patients and lower levels of some cytokines and gamma-tocopherol. This supports the hypothesis that the biology of SCD may show increased inflammation and increased levels of protective antioxidants compared with thalassaemia.

Utility of Holter electrocardiogram in iron-overloaded hemoglobinopathies

Cardiac arrhythmias are among the leading causes of morbidity and mortality of transfusion-dependent, iron-overloaded beta-thalassemia patients. Routine screening with Holter electrocardiogram has been recommended; however, infrequent electrocardiographic changes limit its clinical usefulness. The purpose of this study was to determine the diagnostic yield of Holter electrocardiogram monitoring and its correlation with patient symptoms and disease status. A retrospective analysis was performed on 27 transfusion-dependent thalassemia patients who underwent cardiac questionnaire and Holter screening yearly, in addition to echocardiogram and quantitative iron-level determination. Four patients had clinically significant arrhythmias detected on Holter screening, while 2 patients developed severe cardiac complications secondary to arrhythmias within 1 year of follow-up of normal Holter screening. Early detection of cardiac events among transfusion-dependent thalassemia patients with Holter electrocardiography is not clinically effective. Other screening modalities, including the transtelephonic event recorder, should be evaluated in arrhythmia surveillance.

Objectives and mechanism of iron chelation therapy

Prevention of cardiac mortality is the most important beneficial effect of iron chelation therapy. Unfortunately, compliance with the rigorous requirements of daily subcutaneous deferoxamine (DFO) infusions is still a serious limiting factor in treatment success. The development of orally effective iron chelators such as deferiprone and ICL670 is intended to improve compliance. Although total iron excretion with deferiprone is somewhat less than with DFO, deferiprone may have a better cardioprotective effect than DFO due to deferiprone's ability to penetrate cell membranes. Recent clinical studies indicate that oral ICL670 treatment is well tolerated and is as effective as parenteral DFO used at the standard dose of 40 mg/kg of body weight/day. Thus, for the patient with transfusional iron overload in whom results of DFO treatment are unsatisfactory, several orally effective agents are now available to avoid serious organ damage. Finally, combined chelation treatment is emerging as a reasonable alternative to chelator monotherapy. Combining a weak chelator that has a better ability to penetrate cells with a stronger chelator that penetrates cells poorly but has a more efficient urinary excretion may result in improved therapeutic effect through iron shuttling between the two compounds. The efficacy of combined chelation treatment is additive and offers an increased likelihood of success in patients previously failing DFO or deferiprone monotherapy.

Effect of enhanced iron chelation therapy on glucose metabolism in patients with beta-thalassaemia major

Recently introduced chelation regimens that combine deferoxamine (DFO) and deferiprone have been shown to have greater efficacy in promoting iron excretion than either chelator alone and have been associated with rapid reduction of the iron load in the heart and liver, and with reversal of cardiac dysfunction. It is unclear whether this combined therapy could be associated with a reduction in iron load or decline in the severity of iron-induced endocrinopathies. Starting in January 2001, 42 patients with beta-thalassaemia major, previously maintained on subcutaneous DFO only, were switched to combined treatment with DFO and deferiprone. The primary endpoint was to investigate the effects of this therapy on the glucose metabolism characteristics of this population. Combination therapy markedly decreased ferritin levels (638 +/- 1345 vs. 2991 +/- 2093 microg/l, P < 0.001). Glucose responses were improved at all times during an oral glucose tolerance test, particularly in patients in early stages of glucose intolerance. Glucose quantitative secretion also decreased significantly with combined therapy, while no significant change occurred in insulin levels in any group. Insulin secretion, according to the homeostasis assessment model, markedly increased in all groups, while overall reduction in insulin sensitivity did not reach statistical significance. This study showed that the combination of DFO and deferiprone was associated with an improvement in liver iron deposition and glucose intolerance.

Deferasirox--an oral agent for chronic iron overload

OBJECTIVE

To review the available literature on the pharmacology, pharmacokinetics, efficacy, toxicology, adverse effects, drug interactions, and dosage guidelines for deferasirox, an oral iron chelator, in Phase III trials.

DATA SOURCES

Reviewers searched the following databases for English-language studies: MEDLINE (1966-April 2006), International Pharmaceutical Abstracts (1970-April 2006), and the Cochrane Library Database. Key search terms included iron chelation, chelation, iron overload, deferasirox, and ICL670.

STUDY SELECTION AND DATA EXTRACTION

Data on efficacy, toxicology, adverse effects, and pharmacokinetics for deferasirox were obtained from randomized, open-label, blinded clinical trials. Other information was obtained from the manufacturer, including unpublished studies in abstract form as well as available data on deferasirox.

DATA SYNTHESIS

Deferasirox is an orally active iron chelator. In clinical trials, deferasirox demonstrated efficacy at dosages of 20 and 30 mg/kg/day in treating iron overload in patients with beta-thalassemia. Deferasirox has been studied in patients older than 2 years and appears to be safe, with the most common adverse effects reported being mild, transient nausea, gastrointestinal disturbances, and rash. There were no reports of serious adverse effects in trials to date.

CONCLUSIONS

Deferasirox represents a new approach to the management of chronic iron overload in patients with chronic anemias who require blood transfusions. The available literature suggests that deferasirox is safe and as effective as the current standard of therapy at dosages of 20-30 mg/kg/day for beta-thalassemia. Further studies are needed to confirm its efficacy in other chronic transfusion-requiring diseases.

Prevalence of fractures among the Thalassemia syndromes in North America

Historically, fractures are cited as a frequent problem in patients with Thalassemia prior to optimization of transfusion and chelation regimens. The aim of this study was to determine the prevalence of fractures in a contemporary sample of North American patients with Thalassemia. The North American Thalassemia Clinical Research Network (TCRN) database registry was used to gather historical data on 702 patients with common alpha and beta-Thalassemia diagnoses including Thalassemia Major (TM), Intermedia (TI), E/Beta, homozygous alpha Thalassemia (AT), Hemoglobin H disease (HbH) and HbH with Constant Spring (HbH/CS), who consented to a medical record chart review. Bone mineral density (BMD) measurements by DXA were available for review in a subgroup of patients (n = 312). The overall fracture prevalence among all Thalassemia syndromes was 12.1%, equally distributed between females (11.5%) and males (12.7%). Fractures occurred more frequently in TM (16.6%) and TI (12.2%) compared to E/Beta (7.4%) and alpha (2.3%). Prevalence increased with age (2.5% ages 0-10 years, 7.4% ages 11-19 years, 23.2% ages >20 years) and with use of sex hormone replacement therapy (SHRT) (P < 0.01). On average, BMD Z and T scores were 0.85 SD lower among patients with a history of fractures (mean Z/T score -2.78 vs. -1.93, 95% CI for the difference -0.49 to -1.22 SD, P = 0.02). Presence of other endocrinopathies (i.e. hypothyroidism, hypoparathyroidism and diabetes mellitus), anthropometric parameters, heart disease or hepatitis C were not significant independent predictors of fractures. These data indicate that fractures remain a frequent complication among the aging patients with both TM and TI beta-Thalassemia. However, the fracture prevalence has improved compared to published reports from the 1960s to 1970s. In addition, children with Thalassemia appear to have low fracture rates compared to the general population.

Infections and thalassaemia

Infections are major complications and constitute the second most common cause of mortality and a main cause of morbidity in patients with thalassaemia, a group of genetic disorders of haemoglobin synthesis characterised by a disturbance of globin chain production. Thalassaemias are among the most common genetic disorders in the world. Predisposing factors for infections in thalassaemic patients include severe anaemia, iron overload, splenectomy, and a range of immune abnormalities. Major causative organisms of bacterial infections in thalassaemic patients are Klebsiella spp in Asia and Yersinia enterocolitica in western countries. Transfusion-associated viral infections (especially hepatitis C) can lead to liver cirrhosis and hepatocellular carcinoma. A unique and challenging infection detected in Asian patients is pythiosis, caused by a fungus-like organism, the mortality rate of which is very high. Because the prognosis for thalassaemia has much improved, with many patients surviving to the fifth decade of life in developed countries, it is mandatory to reduce mortality by recognising and presumptively treating infections in these patients as quickly as possible.

A randomized controlled study evaluating the safety and efficacy of deferiprone treatment in thalassemia major patients from Hong Kong

A controlled, open-label and randomized study was conducted to evaluate the safety and efficacy of the oral iron chelator deferiprone (L1) in thalassemia major patients from Hong Kong. Forty-nine patients were recruited in total (median age: 20 years; range: 8 to 40 years). The division of the patients was determined based on liver iron content and put into either the poorly-chelated (Group I) or well-chelated (Group II) groups. In Group I, 20 patients received combined therapy of L1 daily plus desferrioxamine (DFO), in a reduced frequency of twice weekly, while the control group consisted of 16 patients who were treated with DFO alone. In Group II, six patients received L1 only, while the control group consisted of seven patients treated with DFO alone. Only patients who participated for longer than 6 months were analyzed for efficacy (n = 44). The median study period was 18 months. Transient and mild gastrointestinal upset (31%), joint pain (15%) and liver enzyme elevation (23%) were the most common side effects noted for L1. No case of neutropenia was observed in this study. Serum ferritin (SF) levels showed significant decline in the poorly-chelated patients using combined therapy (L1 and reduced frequency DFO) as compared to those on DFO alone. However, their pre- and post-study liver iron content was not significantly different. Evaluation of the well-chelated group demonstrated no significant change in SF or liver iron content in both the study and control arms. We conclude that the short-term use of L1, with or without DFO, was safe and efficacious in our Chinese patient cohort. The long-term efficacy of reducing iron overload by treatment regimens including L1 requires further study.

Bone Marrow Transplantation in Adults with Thalassemia: Treatment and Long-Term Follow-Up

Current regular blood transfusion programs and chelation treatment have considerably improved survival of patients with thalassemia, which resulted in a larger proportion of adult patients. However, disease- and treatment-related complications in these patients progress over time, causing severe morbidity and shortened life expectancy. Stem cell transplantation still remains the only cure currently available for patients with thalassemia. This study updates transplant outcomes in 107 adult patients with median age of 22 years (range, 17-35 years) who received bone marrow transplantation (BMT) from human leukocyte antigen (HLA)-identical related donors between 1988 and 1996 (group A) and describes the results of BMT in 15 adult patients with median age of 21 years (range, 17-31 years) who were treated with a new treatment protocol (Protocol 26) between 1997 and 2003 (group B). The probability of survival, event-free survival, nonrejection mortality, and rejection for group A patients were 66%, 62%, 37%, and 4%, respectively, with a median follow-up of 12 years (range, 8.3-16.2 years). Group B patients treated with the new protocol had some improvement in thalassemia-free survival (67%) and lower transplant-related mortality (27%) than that of previous protocols. However, transplant-related mortality in these high-risk patients remains elevated. Current myeloablative BMT in adult patients is characterized by higher transplant-related toxicity due to an advanced phase of disease. Although this new approach to transplant adult patients with a reduced-dose intensity-conditioning regimen has improved thalassemia-free survival, transplant-related mortality in these high-risk patients remains elevated.

In utero gene therapy: current challenges and perspectives

Over the past few years, considerable progress in prenatal diagnosis and surgery combined with improvements in vector design vindicate a reappraisal of the feasibility of in utero gene therapy for serious monogenetic diseases. As adult gene therapy gathers pace, several apparent obstacles to its application as a treatment may be overcome by pre- or early postnatal treatment. This review will examine the concepts and practice of prenatal vector administration. We aim to highlight the advantages of early therapeutic intervention focusing on diseases that could benefit greatly from a prenatal gene therapy approach. We will pay special attention to the strategies and vectors that are most likely to be used for this application and will speculate on their expected developments for the near future.

Anesthetic management of a patient with β-thalassemia intermedia undergoing splenectomy: a case report

A 37-year-old man with beta-thalassemia intermedia (betaTI), a rare disease caused by partial or complete deficiency of beta-globin chain synthesis, fell into a hemolytic crisis. Severe anemia persisted despite frequent transfusions. Therefore, he was scheduled for splenectomy to alleviate the anemia. The preoperative laboratory data showed marked anemia and liver dysfunction. Echocardiography revealed hyperkinetic left ventricular motion and increased cardiac index (CI), indicating a compensatory hyperdynamic circulation induced by persistent, severe anemia. Our strategy during general anesthesia was to keep the hyperkinetic cardiovascular system steady. Hence, the hemodynamic parameters including the CI were measured using a Swan-Ganz catheter, and other physiological parameters were monitored perioperatively. Anesthesia was maintained with balanced anesthesia: isoflurane at low concentrations and fentanyl to avoid cardiovascular depression. Throughout the operation, vital signs were kept stable and the lactate/pyruvate ratio was unchanged, indicating that anaerobic metabolism did not increase. We report successful anesthetic management with attention to hemodynamic changes in a patient with betaTI.

New developments in iron chelators

PURPOSE OF REVIEW

For three decades, deferoxamine has been the only approved iron chelator. This drug has an extremely short-half life and is not orally absorbed; thus, a search has been ongoing for alternative chelators with less onerous delivery. Recently, several oral iron chelators and variations of deferoxamine to prolong the half-life have been developed. These and the methods of monitoring iron overload are the subjects of this review.

RECENT FINDINGS

New chelators, combinations of chelators and regimens for known chelators and their safety and efficacy are being studied in important preclinical and clinical trials.

SUMMARY

The care and clinical outcomes of patients with thalassemia and other iron-overload disorders may be markedly improved by recent discoveries and novel approaches to chelation therapy.

Hepcidin in iron overload disorders

Hepcidin is the principal regulator of iron absorption in humans. The peptide inhibits cellular iron efflux by binding to the iron export channel ferroportin and inducing its internalization and degradation. Either hepcidin deficiency or alterations in its target, ferroportin, would be expected to result in dysregulated iron absorption, tissue maldistribution of iron, and iron overload. Indeed, hepcidin deficiency has been reported in hereditary hemochromatosis and attributed to mutations in HFE, transferrin receptor 2, hemojuvelin, and the hepcidin gene itself. We measured urinary hepcidin in patients with other genetic causes of iron overload. Hepcidin was found to be suppressed in patients with thalassemia syndromes and congenital dyserythropoietic anemia type 1 and was undetectable in patients with juvenile hemochromatosis with HAMP mutations. Of interest, urine hepcidin levels were significantly elevated in 2 patients with hemochromatosis type 4. These findings extend the spectrum of iron disorders with hepcidin deficiency and underscore the critical importance of the hepcidin-ferroportin interaction in iron homeostasis.

Stem cell transplantation for thalassaemia

Although improvements in conventional treatment have enhanced the prognosis of thalassaemia, stem cell transplantation remains the only cure. Over the last 2 decades, progress in preventive strategies, effective control of transplant related complications and development of new preparative regimens, have considerably improved the results of transplants from HLA-identical siblings. Currently class 1, class 2 and class 3 patients receiving bone marrow transplantation (BMT) from an HLA-identical related donor have 87, 85 and 80% of probability of thalassaemia-free survival. The results of transplant in adult patients treated with current protocols are less successful. This study reports experience with BMT for thalassaemia.