A randomised comparison of deferasirox versus deferoxamine for the treatment of transfusional iron overload in sickle cell disease

Pharmacology of iron transport

Elucidating the molecular basis for the regulation of iron uptake, storage, and distribution is necessary to understand iron homeostasis. Pharmacological tools are emerging to identify and distinguish among different iron transport pathways. Stimulatory or inhibitory small molecules with effects on iron uptake can help characterize the mechanistic elements of iron transport and the roles of the transporters involved in these processes. In particular, iron chelators can serve as potential pharmacological tools to alleviate diseases of iron overload. This review focuses on the pharmacology of iron transport, introducing iron transport membrane proteins and known inhibitors.

How I treat transfusional iron overload

Patients with β-thalassemia major (TM) and other refractory anemias requiring regular blood transfusions accumulate iron that damages the liver, endocrine system, and most importantly the heart. The prognosis in TM has improved remarkably over the past 10 years. This improvement has resulted from the development of magnetic resonance imaging (MRI) techniques, especially T2*, to accurately measure cardiac and liver iron, and from the availability of 3 iron-chelating drugs. In this article we describe the use of MRI to determine which adult and pediatric patients need to begin iron chelation therapy and to monitor their progress. We summarize the properties of each of the 3 drugs, deferoxamine (DFO), deferiprone (DFP), and deferasirox (DFX), including their efficacy, patient acceptability, and side effects. We describe when to initiate or intensify therapy, switch to another drug, or use combined therapy. We also discuss the management of refractory anemias other than TM that may require multiple blood transfusions, including sickle cell anemia and myelodysplasia. The development of a potential fourth chelator FBS 0701 and the combined use of oral chelators may further improve the quality of life and survival in patients with TM and other transfusion-dependent patients.

Indications and complications of transfusions in sickle cell disease

Red cell transfusion remains an important part of the management of acute and chronic complications in SCD. The ongoing and emerging uses of transfusions in SCD may have significant benefits; however, the potential complications of transfusions also deserve careful consideration. In this report we review current indications for transfusions, transfusion complications, modifications of transfusion practices to mitigate risk, and potential considerations to improve transfusion outcomes.

Sickle cell disease in children

Early identification of infants with sickle cell disease (SCD) by newborn screening, now universal in all 50 states in the US, has improved survival, mainly by preventing overwhelming sepsis with the early use of prophylactic penicillin. Routine transcranial Doppler screening with the institution of chronic transfusion decreases the risk of stroke from 10% to 1% in paediatric SCD patients. Hydroxyurea decreases the number and frequency of painful crises, acute chest syndromes and number of blood transfusions in children with SCD. Genetic research continues to be driven toward the prevention and ultimate cure of SCD before adulthood. This review focuses on clinical manifestations and therapeutic strategies for paediatric SCD as well as the evolving topic of gene-focused prevention and therapy.

Efficacy of deferasirox in North Indian β-thalassemia major patients: a preliminary report

Deferasirox (DFX) is a relatively new iron chelator approved by the US Food and Drug Administration for treatment of children >2 years of age. Prospective studies in Asian Indian children are limited. The β-thalassemia patients receiving regular transfusions in the thalassemia ward of an advanced pediatric center were included in this study. Monitoring of side effects was carried out by assessing monthly transaminases and serum creatinine levels. Hemoglobin levels were determined before blood transfusion. Thirty patients of transfusion-dependent thalassemia were eligible for the final analysis. The male:female ratio was 3.3:1, and ages ranged from 2.0 to 21 years. The serum ferritin (SF) level at the start of therapy was 2657.7±1414.6 (mean±SD). The mean dose of DFX was 21.57 mg/kg/d (range, 17.2 to 27.2 mg/kg/d). Common side effects noted were gastrointestinal manifestations in 5 (16.6%) and skin rash in 2 (6.6%) patients. There was an increase in serum creatinine in 2 patients, and treatment was interrupted in 1. Reversible cytopenia was observed in 1 patient. In 13/30 patients, an initial increase in SF was observed. A decrease in SF levels compared with initial value was seen in only 8 patients at a follow-up of 24 months, at a median dose of 28.8 mg/kg/d. Thus, DFX is a relatively safe oral iron chelator that can be used in Asian Indians, with gastrointestinal problems like diarrhea and abdominal pain as the most common side effects. Treatment requires individualization with careful dose escalation and proper monitoring.

Management of children with sickle cell disease: a comprehensive review of the literature

OBJECTIVE

Sickle cell disease (SCD) affects 70 000 to 100 000 people in the United States, and 2000 infants are born with the disease each year. The purpose of this study was to review the quality of the literature for preventive interventions and treatment of complications for children with SCD to facilitate the use of evidence-based medicine in clinical practice and identify areas in need of additional research.

METHODS

We searched the Ovid Medline database and the Cochrane Library for articles published between January 1995 and April 2010 for English-language abstracts on 28 topics thought to be important for the care of children with SCD. We also added pertinent references cited by studies identified in our search. Each abstract was reviewed independently by 2 authors. Data from articles retrieved for full review were abstracted by using a common form.

RESULTS

There were 3188 abstracts screened, and 321 articles underwent full review. Twenty-six articles (<1% of abstracts initially screened), which consisted of 25 randomized controlled trials and 1 meta-analysis, were rated as having level I evidence. Eighteen of the 28 topics selected for this review did not have level I evidence studies published. The management and prevention of pain episodes accounted for more than one-third of the level I studies.

CONCLUSIONS

Although significant strides have been made in the care of children with SCD in the past 2 decades, more research needs to be performed, especially for acute events associated with SCD, to ensure that the health and well-being of children with SCD continues to improve.

The role of galenic innovation in improving treatment compliance and persistence: three case studies

BACKGROUND

The purpose of this study was to explore whether newer galenic formulations with lower treatment burdens are associated with better patient compliance and persistence compared with older more burdensome modalities.

METHODS

Data from the IMS Disease Analyzer database were analyzed retrospectively for two pairs of analogs (alendronate sodium once daily vs once weekly and immediate-release vs extended-release methylphenidate) and one pair of drugs with similar indications but important differences in convenience and dosing instructions (desferrioxamine vs deferasirox). Compliance was calculated as the sum of prescription durations for all prescriptions for each patient over 1 year. Persistence was calculated as the time between first and last prescriptions over 2 years (1 year for deferasirox and desferrioxamine). Data from Germany and the UK were available and used for analysis.

RESULTS

Incremental improvements in compliance were +30% in the UK and +26% in Germany for alendronate once weekly vs once daily, +14% in the UK and +19% in Germany for extended-release vs immediate-release methylphenidate, and +15% in Germany for desferrioxamine vs deferasirox. Incremental improvements in persistence were +9 months in the UK and +8 months in Germany for alendronate once weekly vs once daily, +4 months in the UK and +3 months in Germany for extended-release vs immediate-release methylphenidate, and +2 months in Germany for deferasirox vs desferrioxamine.

CONCLUSION

The new formulations that we evaluated were associated with better compliance and persistence compared with older formulations. Despite the fact that some sources of bias could not be excluded, it is likely that these improvements can be attributed to the lower treatment burdens of the galenic formulations of the drugs considered. Further investigation is required to confirm these findings and to determine whether new galenic formulations can improve health outcomes in routine clinical practice.

Management of transfusional iron overload - differential properties and efficacy of iron chelating agents

Regular red cell transfusion therapy ameliorates disease-related morbidity and can be lifesaving in patients with various hematological disorders. Transfusion therapy, however, causes progressive iron loading, which, if untreated, results in endocrinopathies, cardiac arrhythmias and congestive heart failure, hepatic fibrosis, and premature death. Iron chelation therapy is used to prevent iron loading, remove excess accumulated iron, detoxify iron, and reverse some of the iron-related complications. Three chelators have undergone extensive testing to date: deferoxamine, deferasirox, and deferiprone (although the latter drug is not currently licensed for use in North America where it is available only through compassionate use programs and research protocols). These chelators differ in their modes of administration, pharmacokinetics, efficacy with regard to organ-specific iron removal, and adverse-effect profiles. These differential properties influence acceptability, tolerability and adherence to therapy, and, ultimately, the effectiveness of treatment. Chelation therapy, therefore, must be individualized, taking into account patient preferences, toxicities, ongoing transfusional iron intake, and the degree of cardiac and hepatic iron loading.

Interference of deferasirox with assays for serum iron and serum unsaturated iron binding capacity during iron chelating therapy

BACKGROUND

Deferasirox (DFX) is an oral iron chelator that is used worldwide for the treatment of iron overload. Although serum ferritin level is usually measured as a marker of the efficacy of DFX, we sometimes experienced unexplainable changes in other serum markers for iron. We hypothesized that photometric assays for serum iron (sFe) and unsaturated iron binding capacity (UIBC) might be affected by DFX.

METHODS

Measurement of sFe and UIBC was performed using 4 different assay systems. The samples were prepared by adding 0-300 μM DFX to pooled human serum or 15 randomized human serum samples. In some experiments, DFX-iron complex (DFX-Fe) was prepared by mixing iron ammonium citrate solution and DFX solution.

RESULTS

Measurement of sFe was influenced by DFX-Fe, while iron-free DFX showed no effect on the value of sFe; DFX-Fe was measured as sFe, undistinguishable from transferrin-bound iron. On the other hand, measurement of serum UIBC was influenced by DFX itself; DFX might have been bound to iron in the reagent used for the assay, leading to an increase in UIBC values.

CONCLUSIONS

DFX affected the sFe and UIBC assay systems. We must be careful in observing these markers during iron chelation therapy with DFX.

Response of iron overload to deferasirox in rare transfusion-dependent anaemias: equivalent effects on serum ferritin and labile plasma iron for haemolytic or production anaemias

OBJECTIVES

It is widely assumed that, at matched transfusional iron-loading rates, responses to chelation therapy are similar, irrespective of the underlying condition. However, data are limited for rare transfusion-dependent anaemias, and it remains to be elucidated if response differs, depending on whether the anaemia has a primary haemolytic or production mechanism.

METHODS

The efficacy and safety of deferasirox (Exjade®) in rare transfusion-dependent anaemias were evaluated over 1 yr, with change in serum ferritin as the primary efficacy endpoint. Initial deferasirox doses were 10-30 mg/kg/d, depending on transfusion requirements; 34 patients had production anaemias, and 23 had haemolytic anaemias.

RESULTS

Patients with production anaemias or haemolytic anaemias had comparable transfusional iron-loading rates (0.31 vs. 0.30 mL red blood cells/kg/d), mean deferasirox dosing (19.3 vs. 19.0 mg/kg/d) and baseline median serum ferritin (2926 vs. 2682 ng/mL). Baseline labile plasma iron (LPI) levels correlated significantly with the transfusional iron-loading rates and with serum ferritin levels in both cohorts. Reductions in median serum ferritin levels were initially faster in the production than the haemolytic anaemias, but at 1 yr, similar significant reductions of 940 and 617 ng/mL were attained, respectively (-26.0% overall). Mean LPI decreased significantly in patients with production (P < 0.0001) and haemolytic (P = 0.037) anaemias after the first dose and was maintained at normal mean levels (< 0.4 μm) subsequently. The most common drug-related, investigator-assessed adverse events were diarrhoea (n = 16) and nausea (n = 12).

CONCLUSIONS

At matched transfusional iron-loading rates, the responses of rare transfusion-dependent anaemias to deferasirox are similar at 1 yr, irrespective of the underlying pathogenic mechanism.

Discontinuing prophylactic transfusions increases the risk of silent brain infarction in children with sickle cell disease: data from STOP II

In the STOP II trial, discontinuation of prophylactic transfusions in high risk children with sickle cell disease (SCD) resulted in a high rate of reversion to abnormal blood-flow velocities on transcranial Doppler (TCD) ultrasonography and strokes. We analyzed data from STOP II to determine the effect of discontinuing transfusions on the development or progression of silent brain infarcts on magnetic resonance imaging (MRI). At study entry, 21 of 79 (27%) patients had evidence of silent infarcts. There were no statistically significant differences in baseline characteristics between patients with normal brain MRI or silent infarcts at study entry. At study end, 3 of 37 (8.1%) patients in the continued-transfusion group developed new brain MRI lesions compared with 11 of 40 (27.5%) in the transfusion-halted group (P = .03). The total number of lesions remained essentially unchanged decreasing from 25 to 24 in the continued-transfusion group while increasing from 27 to 45 in transfusion-halted patients. Thus, discontinuation of transfusions in children with SCD and abnormal TCD who revert to low-risk increases the risk of silent brain infarction. Together with data from STOP, these findings demonstrate that transfusions prevent the development of silent infarcts in patients with SCD and abnormal TCD but normal MRA.

Iron chelation with deferasirox in adult and pediatric patients with thalassemia major: efficacy and safety during 5 years' follow-up

Patients with β-thalassemia require lifelong iron chelation therapy from early childhood to prevent complications associated with transfusional iron overload. To evaluate long-term efficacy and safety of once-daily oral iron chelation with deferasirox, patients aged ≥ 2 years who completed a 1-year, phase 3, randomized trial entered a 4-year extension study, either continuing on deferasirox (deferasirox cohort) or switching from deferoxamine to deferasirox (crossover cohort). Of 555 patients who received ≥ 1 deferasirox dose, 66.8% completed the study; 43 patients (7.7%) discontinued because of adverse events. In patients with ≥ 4 years' deferasirox exposure who had liver biopsy, mean liver iron concentration significantly decreased by 7.8 ± 11.2 mg Fe/g dry weight (dw; n = 103; P < .001) and 3.1 ± 7.9 mg Fe/g dw (n = 68; P < .001) in the deferasirox and crossover cohorts, respectively. Median serum ferritin significantly decreased by 706 ng/mL (n = 196; P < .001) and 371 ng/mL (n = 147; P < .001), respectively, after ≥ 4 years' exposure. Investigator-assessed, drug-related adverse events, including increased blood creatinine (11.2%), abdominal pain (9.0%), and nausea (7.4%), were generally mild to moderate, transient, and reduced in frequency over time. No adverse effect was observed on pediatric growth or adolescent sexual development. This first prospective study of long-term deferasirox use in pediatric and adult patients with β-thalassemia suggests treatment for ≤ 5 years is generally well tolerated and effectively reduces iron burden. This trial was registered at www.clinicaltrials.gov as #NCT00171210.

Iron overload and allogeneic hematopoietic stem-cell transplantation

Iron overload is frequently observed in patients with hematologic diseases before and after allogeneic stem-cell transplantation because they usually receive multiple red blood cell transfusions. Elevated pretransplant serum ferritin levels, which are widely used as indicators of body iron status, are significantly associated with a lower overall survival rate and a higher incidence of treatment-related complications; for example, infections and hepatic veno-occlusive disease. As serum ferritin levels are affected, not only by iron loading but also by inflammation, imaging techniques to quantify tissue iron levels have been developed, for example, quantitative MRI using the transverse magnetic relaxation rate, and superconducting quantum interference devices. Iron chelators, such as deferasirox, a new oral iron-chelating agent, reduce iron load in transfusion-dependent patients. Iron-chelating therapy before and/or after transplantation is a promising strategy to improve the clinical outcomes of transplant patients with iron overload. However, further research is needed to prove the direct relationship between iron overload and adverse outcomes, as well as to determine the effects of treatment for iron overload on outcomes of allogeneic stem-cell transplantation.

Long-term safety and efficacy of deferasirox (Exjade) for up to 5 years in transfusional iron-overloaded patients with sickle cell disease

To date, there is a lack of long-term safety and efficacy data for iron chelation therapy in transfusion-dependent patients with sickle cell disease (SCD). To evaluate the long-term safety and efficacy of deferasirox (a once-daily oral iron chelator), patients with SCD completing a 1-year, Phase II, randomized, deferoxamine (DFO)-controlled study entered a 4-year extension, continuing to receive deferasirox, or switching from DFO to deferasirox. Average actual deferasirox dose was 19·4 ± 6·3 mg/kg per d. Of 185 patients who received at least one deferasirox dose, 33·5% completed the 5-year study. The most common reasons for discontinuation were withdrawal of consent (23·8%), lost to follow-up (9·2%) and adverse events (AEs) (7·6%). Investigator-assessed drug-related AEs were predominantly gastrointestinal [including nausea (14·6%), diarrhoea (10·8%)], mild-to-moderate and transient in nature. Creatinine clearance remained within the normal range throughout the study. Despite conservative initial dosing, serum ferritin levels in patients with ≥ 4 years deferasirox exposure significantly decreased by -591 μg/l (95% confidence intervals, -1411, -280 μg/l; P = 0·027; n = 67). Long-term deferasirox treatment for up to 5 years had a clinically acceptable safety profile, including maintenance of normal renal function, in patients with SCD. Iron burden was substantially reduced with appropriate dosing in patients treated for at least 4 years.

Thalassemia: an overview of 50 years of clinical research

The thalassemias are attributable to the defective production of the α- and β-globin polypeptides of hemoglobin. Significant discoveries have illuminated the pathophysiology and enhanced the prevention and treatment of the thalassemias, and this article reviews many of the advances that have occurred in the past 50 years. However, the application of new approaches to the treatment of these disorders has been slow, particularly in the developing world where the diseases are common, but there is definite progress. This article emphasizes how the increasing knowledge of cellular and molecular biology are facilitating the development of more effective therapies for these patients.

Iron overload in thalassemia and related conditions: therapeutic goals and assessment of response to chelation therapies

Transfusional iron loading inevitably results in hepatic iron accumulation, with variable extrahepatic distribution that is typically less pronounced in sickle cell disease than in thalassemia disorders. Iron chelation therapy has the goal of preventing iron-mediated tissue damage through controlling tissue iron levels, without incurring chelator-mediated toxicity. Historically, target levels for tissue iron control have been limited by the increased frequency of deferoxamine-mediated toxicity and low levels of iron loading. With newer chelation regimes, these limitations are less evident. The reporting of responses to chelation therapies has typically focused on average changes in serum ferritin in patient populations. This approach has three limitations. First, changes in serum ferritin may not reflect trends in iron balance equally in all patients or for all chelation regimens. Second, this provides no information about the proportion of patients likely respond. Third, this gives insufficient information about iron trends in tissues such as the heart. Monitoring of iron overload has advanced with the increasing use of MRI techniques to estimate iron balance (changes in liver iron concentration) and extrahepatic iron distribution (myocardial T2*). The term nonresponder has been increasingly used to describe individuals who fail to show a downward trend in one or more of these variables. Lack of a response of an individual may result from inadequate dosing, high transfusion requirement, poor treatment adherence, or unfavorable pharmacology of the chelation regime. This article scrutinizes evidence for response rates to deferoxamine, deferiprone (and combinations), and deferasirox.

Current strategies for the management of children with sickle cell disease

Children with sickle cell disease may present to doctors anywhere in the world. In developed countries, neonatal screening allows early identification and management of the disease, mostly through daily antibioprophylaxis, immunizations and education of the parents. Stroke prevention relies on the detection of high-risk patients by annual transcranial Doppler ultrasonography from 2 to 16 years of age. Annual check-ups aim to detect early organ deficiencies. The most frequent complications are pain, infections and acute anemia; they may occur in combination. Approximately 10% of children have severe sickle cell disease that may require chronic blood transfusion, hydroxyurea or hematopoietic stem cell transplantation. Comprehensive management programs have dramatically increased survival, and most patients now reach adulthood.

Transfusion and chelation practices in sickle cell disease: a regional perspective

Although most common in tropical regions, population migration has meant that sickle cell disease is now one of the most prevalent genetic diseases worldwide. The issues and challenges faced by physicians and patients have been discussed by an international group of experts representing 4 key regions: the USA, Europe, Latin America, and the Middle East/Africa. Conclusive evidence to support the use of transfusion therapy for the prevention of stroke has resulted in key changes to patient management in all regions, and increasing numbers of patients are benefiting from this management approach. However, it is apparent that transfusion therapy is still under-utilized, largely due to concerns over iron overload, alloimmunization, limited blood supplies, and, sometimes, due to parental refusal. Once transfused, assessment and management of body iron levels can be poor, particularly in patients who are intermittently transfused. Compliance with chelation therapy regimens is a significant challenge, but new therapeutic options are likely to overcome some of the current barriers. Key requirements in all regions were considered to be the following: to provide greater physician, patient, and family education; to ensure effective transition from pediatric to adult care; and to establish national guidelines in order to ensure best practice is consistently applied.

Iron in sickle-cell disease: what have we learned over the years?

Over the last four decades, monumental advances have been made in the understanding, assessment, and management of transfusion-dependent patients, which have translated into significant improvements in patient morbidity and mortality. Important lessons have been learned from extensive clinical experience of iron management in the thalassemias, but greater knowledge of key differences in the sickle-cell disease (SCD) population may impact on our approach to patient assessment and management. The unique pathophysiology of SCD is reflected in a distinct pattern of iron loading with minimal organ-specific injury. An appreciation and understanding of these differences should allow us to develop tailored management approaches that optimize patient outcomes.

Approaches to transfusion therapy and iron overload in patients with sickle cell disease: results of an international survey

To gain an insight into current transfusion and chelation practice in patients with sickle cell disease (SCD), a survey of international experts has been conducted. The findings demonstrate that general utilization of transfusion therapy is low, the primary barrier to treatment being concerns over resultant iron overload and the subsequent need for iron chelation therapy. Where patients were transfused, many physicians indicated that a high proportion of patients had hemosiderosis. As evidence suggests more patients with SCD could benefit from regular transfusion therapy, it is apparent that greater awareness of the need to monitor and treat iron overload in transfused patients is required.

Iron-chelating therapy for transfusional iron overload

A 16-year-old boy with sickle cell anemia undergoes routine screening with transcranial Doppler ultrasonography to assess the risk of stroke. This examination shows an abnormally elevated blood-flow velocity in the middle cerebral artery. The hemoglobin level is 7.2 g per deciliter, the reticulocyte count is 12.5%, and the fetal hemoglobin level is 8.0%. Long-term treatment with red-cell transfusion is initiated to prevent stroke. A hematologist recommends prophylactic iron-chelating therapy.

Sickle-cell disease

Sickle-cell disease is one of the most common severe monogenic disorders in the world. Haemoglobin polymerisation, leading to erythrocyte rigidity and vaso-occlusion, is central to the pathophysiology of this disease, although the importance of chronic anaemia, haemolysis, and vasculopathy has been established. Clinical management is basic and few treatments have a robust evidence base. One of the main problems of sickle-cell disease in children is the development of cerebrovascular disease and cognitive impairment, and the role of blood transfusion and hydroxycarbamide for prevention of these complications is starting to be understood. Recurrent episodes of vaso-occlusion and inflammation result in progressive damage to most organs, including the brain, kidneys, lungs, bones, and cardiovascular system, which becomes apparent with increasing age. Most people with sickle-cell disease live in Africa, where little is known about this disease; however, we do know that the disorder follows a more severe clinical course in Africa than for the rest of the world and that infectious diseases have a role in causing this increased severity of sickle-cell disease. More work is needed to develop effective treatments that specifically target pathophysiological changes and clinical complications of sickle-cell disease.

A phase 1/2, dose-escalation trial of deferasirox for the treatment of iron overload in HFE-related hereditary hemochromatosis

Hereditary hemochromatosis (HH) is characterized by increased intestinal iron absorption that may result in iron overload. Although phlebotomy is widely practiced, it is poorly tolerated or contraindicated in patients with anemias, severe heart disease, or poor venous access, and compliance can vary. The once-daily, oral iron chelator, deferasirox (Exjade) may provide an alternative treatment option. Patients with HH carrying the HFE gene who were homozygous for the Cys282Tyr mutation, serum ferritin levels of 300-2000 ng/mL, transferrin saturation ≥ 45%, and no known history of cirrhosis were enrolled in this dose-escalation study to characterize the safety and efficacy of deferasirox, comprising a core and an extension phase (each 24 weeks). Forty-nine patients were enrolled and received starting deferasirox doses of 5 (n = 11), 10 (n = 15), or 15 (n = 23) mg/kg/day. Adverse events were generally dose-dependent, the most common being diarrhea, headache, and nausea (n = 18, n = 10, and n = 8 in the core and n = 1, n = 1, and n = 0 in the extension, respectively). More patients in the 15 mg/kg/day than in the 5 or 10 mg/kg/day cohorts experienced increases in alanine aminotransferase and serum creatinine levels during the 48-week treatment period; six patients had alanine aminotransferase > 3 × baseline and greater than the upper limit of normal range, and eight patients had serum creatinine > 33% above baseline and greater than upper limit of normal on two consecutive occasions. After receiving deferasirox for 48 weeks, median serum ferritin levels decreased by 63.5%, 74.8%, and 74.1% in the 5, 10, and 15 mg/kg/day cohorts, respectively. In all cohorts, median serum ferritin decreased to < 250 ng/mL.

CONCLUSION

Deferasirox doses of 5, 10, and 15 mg/kg/day can reduce iron burden in patients with HH. Based on the safety and efficacy results, starting deferasirox at 10 mg/kg/day appears to be most appropriate for further study in this patient population.

Iron overload cardiomyopathy: better understanding of an increasing disorder

The prevalence of iron overload cardiomyopathy (IOC) is increasing. The spectrum of symptoms of IOC is varied. Early in the disease process, patients may be asymptomatic, whereas severely overloaded patients can have terminal heart failure complaints that are refractory to treatment. It has been shown that early recognition and intervention may alter outcomes. Biochemical markers and tissue biopsy, which have traditionally been used to diagnose and guide therapy, are not sensitive enough to detect early cardiac iron deposition. Newer diagnostic modalities such as magnetic resonance imaging are noninvasive and can assess quantitative cardiac iron load. Phlebotomy and chelating drugs are suboptimal means of treating IOC; hence, the roles of gene therapy, hepcidin, and calcium channel blockers are being actively investigated. There is a need for the development of clinical guidelines in order to improve the management of this emerging complex disease.

Iron overload in patients undergoing hematopoietic stem cell transplantation

Recipients of hematopoietic stem cell transplantation (HSCT) frequently have iron overload resulting from chronic transfusion therapy for anemia. In some cases, for example, in patients with myelodysplastic syndromes and thalassemia, this can be further exacerbated by increased absorption of iron from the gut as a result of ineffective erythropoiesis. Accumulating evidence has established the negative impact of elevated pretransplantation serum ferritin, a surrogate marker of iron overload, on overall survival and nonrelapse mortality after HSCT. Complications of HSCT associated with iron overload include increased bacterial and fungal infections as well as sinusoidal obstruction syndrome and possibly other regimen-related toxicities. Based on current evidence, particular attention should be paid to prevention and management of iron overload in allogeneic HSCT candidates, especially in patients with thalassemia and myelodysplastic syndromes. The pathophysiology of iron overload in the HSCT patient and optimum strategies to deal with iron overload during and after HSCT require further study.

Deferasirox for managing transfusional iron overload in people with sickle cell disease

BACKGROUND

Sickle cell disease (SCD) is a group of genetic haemoglobin disorders. Increasingly, some people with SCD develop secondary iron overload due to occasional red blood cell transfusions or are on long-term transfusion programmes for e.g. secondary stroke prevention. Iron chelation therapy can prevent long-term complications.Deferoxamine and deferiprone have been found to be efficacious. However, questions exist about the effectiveness and safety of the new oral chelator deferasirox.

OBJECTIVES

To assess the effectiveness and safety of oral deferasirox in people with SCD and secondary iron overload.

SEARCH STRATEGY

We searched the Cystic Fibrosis & Genetic Disorders Group's Haemoglobinopathies Trials Register (06 April 2010).We searched MEDLINE, EMBASE, EBMR, Biosis Previews, Web of Science, Derwent Drug File, XTOXLINE and three trial registries: www.controlled-trials.com; www.clinicaltrials.gov; www.who.int./ictrp/en/. Most recent searches: 22 June 2009.

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. We contacted the study author for additional information.

MAIN RESULTS

One study (203 people) was included comparing the efficacy and safety of deferasirox and deferoxamine after 12 months. Data were not available on mortality or end-organ damage. Using a pre-specified dosing algorithm serum ferritin reduction was similar in both groups, mean difference (MD) 375.00 microg/l in favour of deferoxamine; (95% confidence interval (CI) -106.08 to 856.08). Liver iron concentration measured by superconduction quantum interference device showed no difference for the overall group of patients adjusted for transfusion category, MD -0.20 mg Fe/g dry weight (95% CI -3.15 to 2.75).Mild stable increases in creatine were observed more often in people treated with deferasirox, risk ratio 1.64 (95% CI 0.98 to 2.74). Abdominal pain and diarrhoea occurred significantly more often in people treated with deferasirox. Rare adverse events (less than 5% increase) were not reported; long-term adverse events could not be measured in the included study (follow-up 52 weeks). Patient satisfaction with, and convenience of treatment were significantly better with deferasirox.

AUTHORS' CONCLUSIONS

Deferasirox appears to be as effective as deferoxamine. However, only limited evidence is available assessing the efficacy regarding patient-important outcomes. The short-term safety of deferasirox seems to be acceptable, however, follow-up was too short to exclude long-term side effects and thus treatment with deferasirox cannot be judged completely safe. Future studies should assess long-term outcomes for safety and efficacy, and also evaluate rarer adverse effects.

Posttransplant oral iron-chelating therapy in patients with beta-thalassemia major

Allogeneic hematopoetic stem cell transplantation (HSCT) is the only radical cure of beta-thalassemia. However, iron overload remains a cause of morbidity and mortality in posttransplant period. The authors present 7 patients as a preliminary report who underwent bone marrow transplant (BMT) and received oral chelating therapy (deferasirox) because of poor compliance to phlebotomy and desferrioxamine. The patients investigated mainly for possible side effects of deferasirox. No negative effect was seen in aspartate aminotransferase (AST), alanine aminotransferase (ALT), hemoglobin (Hb), and donor chimerism of the patients while serum ferritin levels significantly reduced (P = .018). Although serum creatinin significantly increased (P = .034), it was in normal limits in all patients. The authors believe that this report shows promising findings to plan further studies to clarify clinical safety and efficacy of deferasirox in posttransplant period.

The effect of deferasirox on cardiac iron in thalassemia major: impact of total body iron stores

We present results from a prospective, multicenter, open-label, single-arm study evaluating response of cardiac and liver iron to deferasirox therapy for 18 months. Twenty-eight patients with abnormal T2* and normal left ventricular ejection fraction were enrolled from 4 US centers. All patients initially received deferasirox doses of 30 to 40 mg/kg per day. Patients were severely iron overloaded: mean liver iron concentration (LIC) 20.3 mg Fe/g dry weight, serum ferritin 4417 ng/mL, and cardiac T2* 8.6 ms. In the intent-to-treat population, 48% reached the primary endpoint (cardiac T2* improvement at 18 months, P = not significant). There were 2 deaths: 1 from congestive heart failure and 1 from sepsis. In the 22 patients completing the trial, LIC and cardiac T2* improvements were 16% (P = .06) and 14% (P = .07), respectively. Cardiac T2* improvement (13 patients) was predicted by initial LIC, final LIC, and percentage LIC change, but not initial cardiac T2*. Cardiac iron improved 24% in patients having LIC in the lower 2 quartiles and worsened 8.7% in patients having LIC in the upper 2 quartiles. Left ventricular ejection fraction was unchanged at all time points. Monotherapy with deferasirox was effective in patients with mild to moderate iron stores but failed to remove cardiac iron in patients with severe hepatic iron burdens. This study was registered at www.clinicaltrials.gov as #NCT00447694.

Diagnosis and management of pediatric arterial ischemic stroke

Pediatric stroke is among the top 10 causes of death in children and an important cause of chronic morbidity, with an incidence of 3.3/100,000 children/year. Risk factors associated with stroke in children include cardiac diseases, hematologic and vascular disorders, and infection. Clinical presentation varies depending on age, underlying cause, and stroke location. Antithrombotics and anticoagulants are used in the treatment of pediatric stroke; however, there are no established guidelines for the use of these agents in children. In this article we review the cause, pathophysiology, clinical presentation, diagnosis, acute management, secondary prevention, and outcome of children with stroke. The approach to patients with sickle cell disease and Moyamoya disease is also discussed. Up to date studies to determine the optimal acute treatment of childhood stroke and secondary prevention and risk factor modification are critically needed.

Iron chelation therapy with deferasirox in patients with aplastic anemia: a subgroup analysis of 116 patients from the EPIC trial

The prospective 1-year Evaluation of Patients' Iron Chelation with Exjade (EPIC) study enrolled a large cohort of 116 patients with aplastic anemia; the present analyses evaluated the efficacy and safety of deferasirox in this patient population. After 1 year, median serum ferritin decreased significantly from 3254 ng/mL at baseline to 1854 ng/mL (P < .001). Decreases occurred in chelation-naive (3229-1520 ng/mL; P < .001, last-observation-carried-forward analysis), and previously chelated (3263-2585 ng/mL; P = .21, last-observation-carried-forward analysis) patients and were reflective of dose adjustments and ongoing iron intake. Baseline labile plasma iron levels were within normal range despite high serum ferritin levels. The most common drug-related adverse events were nausea (22%) and diarrhea (16%). Serum creatinine increases more than 33% above baseline and the upper limit of normal occurred in 29 patients (25%), but there were no progressive increases; concomitant use of cyclosporine had a significant impact on serum creatinine levels. The decrease in mean alanine aminotransferase levels at 1 year correlated significantly with reduction in serum ferritin (r = 0.40, P < .001). Mean absolute neutrophil and platelet counts remained stable during treatment, and there were no drug-related cytopenias. This prospective dataset confirms the efficacy and well characterizes the tolerability profile of deferasirox in a large population of patients with aplastic anemia. This study was registered at www.clinicaltrials.gov as #NCT00171821.

Iron chelation therapy in myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a heterogeneous disorder of the hematopoietic stem cells, frequently characterized by anemia and transfusion dependency. In low-risk patients, transfusion dependency can be long lasting, leading to iron overload. Iron chelation therapy may be a therapeutic option for these patients, especially since the approval of oral iron chelators, which are easier to use and better accepted by the patients. The usefulness of iron chelation in MDS patients is still under debate, mainly because of the lack of solid prospective clinical trials that should take place in the future. This review aims to summarize what is currently known about the incidence and clinical consequences of iron overload in MDS patients and the state-of the-art of iron chelation therapy in this setting. We also give an overview of clinical guidelines for chelation in MDS published to date and some perspectives for the future.

Gastrointestinal and hepatic complications of sickle cell disease

Sickle cell disease (SCD) is an autosomal recessive abnormality of the beta-globin chain of hemoglobin (Hb), resulting in poorly deformable sickled cells that cause microvascular occlusion and hemolytic anemia. The spleen is almost always affected by SCD, with microinfarcts within the first 36 months of life resulting in splenic atrophy. Acute liver disorders causing right-sided abdominal pain include acute vaso-occlusive crisis, liver infarction, and acute hepatic crisis. Chronic liver disease might be due to hemosiderosis and hepatitis and possibly to SCD itself if small, clinically silent microvascular occlusions occur chronically. Black pigment gallstones caused by elevated bilirubin excretion are common. Their small size permits them to travel into the common bile duct but cause only low-grade obstruction, so hyperbilirubinemia rather than bile duct dilatation is typical. Whether cholecystectomy should be done in asymptomatic individuals is controversial. The most common laboratory abnormality is an elevation of unconjugated bilirubin level. Bilirubin and lactate dehydrogenase levels correlate with one another, suggesting that chronic hemolysis and ineffective erythropoiesis, rather than liver disease, are the sources of hyperbilirubinemia. Abdominal pain is very common in SCD and is usually due to sickling, which resolves with supportive care. Computed tomography scans might be ordered for severe or unremitting pain. The liver typically shows sickled erythrocytes and Kupffer cell enlargement acutely and hemosiderosis chronically. The safety of liver biopsies has been questioned, particularly during acute sickling crisis. Treatments include blood transfusions, exchange transfusions, iron-chelating agents, hydroxyurea, and allogeneic stem-cell transplantation.

Iron chelation therapy with deferasirox results in improvement of liver enzyme level in patients with iron overload-associated liver dysfunction

Iron chelation therapy (ICT) has been applied for the patients with iron overload-associated liver dysfunction since it is one of the causes of death in patients with intractable hematological diseases requiring multiple red blood cell transfusions. Recently, deferasirox (DSX), a novel, once-daily oral iron chelator, was demonstrated to have similar efficacy to the conventional continuous infusion of deferoxamine on a decrease in serum ferritin (SF) level in heavily transfused patients. We show three cases of transfusion-mediated iron-overloaded patients with an elevated serum alanine aminotransaminase (ALT). All three patients who received the ICT with DSX showed a decrease in ALT level in association with a decrease in SF level. It is suggested that DSX therapy could be considered to expect the improvement of liver damage for iron-overloaded patients with an abnormal ALT level.

Iron overload in sickle cell disease

In sickle cell disease transfusions improve blood flow by reducing the proportion of red cells capable of forming sickle hemoglobin polymer. This limits hemolysis and the endothelial damage that result from high proportions of sickle polymer-containing red cells. Additionally, transfusions are used to increase blood oxygen carrying capacity in sickle cell patients with severe chronic anemia or with severe anemic episodes. Transfusion is well-defined as prophylaxis (stroke) and as therapy (acute chest syndrome and stroke) for major complications of sickle cell disease and has been instituted, based on less conclusive data, for a range of additional complications, such as priapism, vaso-occlusive crises, leg ulcers, pulmonary hypertension, and during complicated pregnancies. The major and unavoidable complication of transfusions in sickle cell disease is iron overload. This paper provides an overview of normal iron metabolism, iron overload in transfused patients with sickle cell disease, patterns of end organ damage, diagnosis, treatment, and prevention of iron overload.