Most deaths in beta-thalassemia major result from cardiac complications due to iron overload. Differential effects on myocardial siderosis may exist between different chelators. A randomized controlled trial was performed in 61 patients previously maintained on subcutaneous deferoxamine. The primary end point was the change in myocardial siderosis (myocardial T2*) over 1 year in patients maintained on subcutaneous deferoxamine or those switched to oral deferiprone monotherapy. The dose of deferiprone was 92 mg/kg/d and deferoxamine was 43 mg/kg for 5.7 d/wk. Compliance was 94% ؎ 5.3% and 93% ؎ 9.7% (P ؍ .81), respectively. The improvement in myocardial T2* was significantly greater for deferiprone than deferoxamine (27% vs 13%; P ؍ .023). Left ventricular ejection fraction increased significantly more in the deferipronetreated group (3.1% vs 0.3% absolute units; P ؍ .003). The changes in liver iron level (؊0.93 mg/g dry weight vs ؊1.54 mg/g dry weight; P ؍ .40) and serum ferritin level (؊181 g/L vs ؊466 g/L; P ؍ .16), respectively, were not significantly different between groups. The most frequent adverse events were transient gastrointestinal symptoms for deferipronetreated patients and local reactions at the infusion site for deferoxamine. There were no episodes of agranulocytosis. Deferiprone monotherapy was significantly more effective than deferoxamine over 1 year in improving asymptomatic myocardial siderosis in beta-thalassemia major. (Blood. 2006;107: 3738-3744)
Summary
Cardiac and endocrine disorders are common sequelae of iron overload in transfused thalassaemia patients. Combined chelation with desferrioxamine (DFO) and deferiprone (DFP) is well tolerated and produces an additive/synergistic effect superior to either drug alone. 52 thalassaemia major patients were transitioned from DFO to combined chelation with DFO and DFP. Serum ferritin, cardiac and hepatic iron levels were monitored regularly for up to 7 years, as were cardiac and endocrine function. Patients’ iron load normalized, as judged by ferritin and cardiac and hepatic magnetic resonance imaging findings. In all 12 patients receiving treatment for cardiac dysfunction, symptoms reversed following combined chelation, enabling nine patients to discontinue heart medications. In the 39 patients with abnormal glucose metabolism, 44% normalized. In 18 requiring thyroxine supplementation for hypothyroidism, 10 were able to discontinue, and four reduced their thyroxine dose. In 14 hypogonadal males on testosterone therapy, seven stopped treatment. Of the 19 females, who were hypogonadal on DFO monotherapy, six were able to conceive. Moreover, no patients developed de novo cardiac or endocrine complications. These results suggest that intensive combined chelation normalized patients’ iron load and thereby prevented and reversed cardiac and multiple endocrine complications associated with transfusion iron overload.
Recent advances in magnetic resonance imaging (MRI) techniques allow the assessment of iron overload in tissues 1 especially the heart, 2 in transfusion-dependent thalassemia patients. The R2* value (1/T2*) recorded in the intraventricular septum of the heart indirectly measures the degree of cardiac iron load. Applying this new technology we looked at a number of historical and biochemical parameters in order to determine their relationship to cardiac iron overload and the effect of cardiac iron on functional and structural changes of the heart in transfusion-dependent thalassemics. Haematologica 2007; 92:131-132
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