Follow-up report on the 2-year cardiac data from a deferasirox monotherapy trial

Sustained improvements in myocardial T2* over 2 years in severely iron-overloaded patients with beta thalassemia major treated with deferasirox or deferoxamine

Long-term controlled studies are needed to inform on the clinical benefit of chelation therapy for myocardial iron removal in transfusion-dependent beta thalassemia patients. In a 1-year nonrandomized extension to the CORDELIA study, data collected from patients with myocardial siderosis provided additional information on deferasirox or deferoxamine (DFO) efficacy and safety. Myocardial (m)T2* increased from baseline 11.6 to 15.9 ms in patients receiving deferasirox for 24 months (n = 74; geometric mean [Gmean ] ratio of month 24/baseline 1.38 [95% confidence interval 1.28, 1.49]) and from 10.8 to 14.2 ms in those receiving DFO (n = 29; Gmean ratio 1.33 [1.13, 1.55]; P = 0.93 between groups). Improved mT2* with deferasirox was evident across all subgroups evaluated irrespective of baseline myocardial (mT2* < 10 vs. ≥ 10 ms) or liver (LIC <15 vs. ≥15 mg Fe/g dw) iron burden. Mean LVEF was stable and remained within normal limits with deferasirox or DFO. Liver iron concentration decreased from high baseline values of 30.6 ± 18.0 to 14.4 ± 16.6 mg Fe/g dw at month 24 in deferasirox patients and from 36.8 ± 15.6 to 11.0 ± 12.1 mg Fe/g dw in DFO patients. The long-term safety profile of deferasirox or DFO was consistent with previous reports; serious drug-related AEs were reported in 6.8% of deferasirox and 6.9% of DFO patients. Continued treatment of severely iron-overloaded beta thalassemia patients with deferasirox or DFO led to sustained improvements in myocardial iron irrespective of high or low baseline myocardial or liver iron burden, in parallel with substantial improvements in liver iron (Clinicaltrials.gov identifier: NCT00600938).

A 1-year randomized controlled trial of deferasirox vs deferoxamine for myocardial iron removal in β-thalassemia major (CORDELIA)

Randomized comparison data on the efficacy and safety of deferasirox for myocardial iron removal in transfusion dependent patients are lacking. CORDELIA was a prospective, randomized comparison of deferasirox (target dose 40 mg/kg per day) vs subcutaneous deferoxamine (50-60 mg/kg per day for 5-7 days/week) for myocardial iron removal in 197 β-thalassemia major patients with myocardial siderosis (T2* 6-20 milliseconds) and no signs of cardiac dysfunction (mean age, 19.8 years). Primary objective was to demonstrate noninferiority of deferasirox for myocardial iron removal, assessed by changes in myocardial T2* after 1 year using a per-protocol analysis. Geometric mean (Gmean) myocardial T2* improved with deferasirox from 11.2 milliseconds at baseline to 12.6 milliseconds at 1 year (Gmeans ratio, 1.12) and with deferoxamine (11.6 milliseconds to 12.3 milliseconds; Gmeans ratio, 1.07). The between-arm Gmeans ratio was 1.056 (95% confidence interval [CI], 0.998, 1.133). The lower 95% CI boundary was greater than the prespecified margin of 0.9, establishing noninferiority of deferasirox vs deferoxamine (P = .057 for superiority of deferasirox). Left ventricular ejection fraction remained stable in both arms. Frequency of drug-related adverse events was comparable between deferasirox (35.4%) and deferoxamine (30.8%). CORDELIA demonstrated the noninferiority of deferasirox compared with deferoxamine for myocardial iron removal. This trial is registered at www.clinicaltrials.gov as #NCT00600938.

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

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

Treating thalassemia major-related iron overload: the role of deferiprone

Over the last 20 years, management for thalassemia major has improved to the point where we predict that patients’ life expectancy will approach that of the normal population. These outcomes result from safer blood transfusions, the availability of three iron chelators, new imaging techniques that allow specific organ assessment of the degree of iron overload, and improvement in the treatment of hepatitis. In October 2011, the Food and Drug Administration licensed deferiprone, further increasing the available choices for iron chelation in the US. The ability to prescribe any of the three chelators as well as their combinations has led to more effective reduction of total body iron. The ability to determine the amount of iron in the liver and heart by magnetic resonance imaging allows the prescription of the most appropriate chelation regime for patients and to reconsider what our aims with respect to total body iron should be. Recent evidence from Europe has shown that by normalizing iron stores not only are new morbidities prevented but also reversal of many complications such as cardiac failure, hypothyroidism, hypogonadism, impaired glucose tolerance, and type 2 diabetes can occur, improving survival and patients’ quality of life. The most effective way to achieve normal iron stores seems to be with the combination of deferoxamine and deferiprone. Furthermore, outcomes should continue to improve in the future. Starting relative intensive chelation in younger children may prevent short stature and abnormal pubertal maturation as well as other iron-related morbidities. Also, further information should become available on the use of other combinations in chelation treatment, some of which have been used only in a very limited fashion to date. All these advances in management require absolute cooperation and understanding of parents, children, and, subsequently, the patients themselves. Only with such cooperation can normal long-term survival be achieved, as adherence to treatment is now likely the primary barrier to longevity.

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

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

Deferasirox for up to 3 years leads to continued improvement of myocardial T2* in patients with β-thalassemia major

BACKGROUND

Prospective data on cardiac iron removal are limited beyond one year and longer-term studies are, therefore, important.

DESIGN AND METHODS

Seventy-one patients in the EPIC cardiac substudy elected to continue into the 3(rd) year, allowing cardiac iron removal to be analyzed over three years.

RESULTS

Mean deferasirox dose during year 3 was 33.6 ± 9.8 mg/kg per day. Myocardial T2*, assessed by cardiovascular magnetic resonance, significantly increased from 12.0 ms ± 39.1% at baseline to 17.1 ms ± 62.0% at end of study (P<0.001), corresponding to a decrease in cardiac iron concentration (based on ad hoc analysis of T2*) from 2.43 ± 1.2 mg Fe/g dry weight (dw) at baseline to 1.80 ± 1.4 mg Fe/g dw at end of study (P<0.001). After three years, 68.1% of patients with baseline T2* 10 to <20 ms normalized (≥ 20 ms) and 50.0% of patients with baseline T2* >5 to <10 ms improved to 10 to <20 ms. There was no significant variation in left ventricular ejection fraction over the three years. No deaths occurred and the most common investigator-assessed drug-related adverse event in year 3 was increased serum creatinine (n = 9, 12.7%).

CONCLUSIONS

Three years of deferasirox treatment along with a clinically manageable safety profile significantly reduced cardiac iron overload versus baseline and normalized T2* in 68.1% (32 of 47) of patients with T2* 10 to <20 ms.

On improvement in ejection fraction with iron chelation in thalassemia major and the risk of future heart failure

BACKGROUND

Trials of iron chelator regimens have increased the treatment options for cardiac siderosis in beta-thalassemia major (TM) patients. Treatment effects with improved left ventricular (LV) ejection fraction (EF) have been observed in patients without overt heart failure, but it is unclear whether these changes are clinically meaningful.

METHODS

This retrospective study of a UK database of TM patients modelled the change in EF between serial scans measured by cardiovascular magnetic resonance (CMR) to the relative risk (RR) of future development of heart failure over 1 year. Patients were divided into 2 strata by baseline LVEF of 56-62% (below normal for TM) and 63-70% (lower half of the normal range for TM).

RESULTS

A total of 315 patients with 754 CMR scans were analyzed. A 1% absolute increase in EF from baseline was associated with a statistically significant reduction in the risk of future development of heart failure for both the lower EF stratum (EF 56-62%, RR 0.818, p < 0.001) and the higher EF stratum (EF 63-70%, RR 0.893 p = 0.001).

CONCLUSION

These data show that during treatment with iron chelators for cardiac siderosis, small increases in LVEF in TM patients are associated with a significantly reduced risk of the development of heart failure. Thus the iron chelator induced improvements in LVEF of 2.6% to 3.1% that have been observed in randomized controlled trials, are associated with risk reductions of 25.5% to 46.4% for the development of heart failure over 12 months, which is clinically meaningful. In cardiac iron overload, heart mitochondrial dysfunction and its relief by iron chelation may underlie the changes in LV function.

Oral chelators in transfusion-dependent thalassemia major patients may prevent or reverse iron overload complications

Combined chelation treatment may be a better approach for transfusion-dependent thalassemia major patients with iron overload complications because of increased efficacy. Combination therapy with desferrioxamine and deferiprone has already been reported to improve survival dramatically by reversing cardiac dysfunction and other endocrine complications. Some patients have intolerance or inconvenience to parenteral desferrioxamine. The hypothesis of this study was that combining two oral chelators, deferiprone and deferasirox, might lead to similar results. Following approval by the hospital ethical committee and a written informed consent from each patient, 16 patients who fulfilled the criteria participated in a study protocol for a period of up to 2 years. Efficacy measures analysis demonstrated a statistically significant decrease of total body iron load as estimated by serum ferritin, LIC and MRI T2* indices. Regarding the safety assessment, the incidence of adverse events was minor compared to the associated toxicity of monotherapy of each drug. No new onset of iron overload-related complications was demonstrated. A reversal of cardiac dysfunction was observed in 2/4 patients, while the mean LVEF increased significantly. Regarding endocrine assessment, in 2/8 patients with impaired glucose tolerance, we noted a significant decrease in the mean 2h glucose in OGTT. Additionally an improvement in gonadal function was observed and one male and one female gave birth to two healthy children without hormonal stimulation. Combined oral chelation in thalassemia offers the promise of easier administration, better compliance and may lead to an improvement of patient quality of life by preventing or even reversing iron overload complications.