Monitoring long-term efficacy of iron chelation therapy by deferiprone and desferrioxamine in patients with β-thalassaemia major: application of SQUID biomagnetic liver susceptometry

Summary. In this non-randomized prospective study, liver and spleen iron concentrations were monitored annually over a 4-year period by non-invasive Superconducting Quantum Interference Device biomagnetometry in 54 β-thalassaemia major patients (age, 7–22 years) receiving treatment with deferiprone (75 mg/kg/d). Median liver iron concentrations increased significantly from 1456 to 2029 and 2449 µg/g_liver at baseline, after 2·0 and 3·2 years respectively. Another group of 51 thalassaemic patients (aged 4–34 years) who received desferrioxamine s.c. for 1·9 years increased their liver iron concentration from 1076 to 1260 µg/g_liver. Taking into account the increase of the daily iron input from transfusions of 3·6 mg/d, caused by weight gain in 67% of the patients treated with deferiprone, a larger total body iron elimination rate was achieved after 2 years than at baseline. A negative ferritin change was observed in 51% of the patients. In 15 non-splenectomized patients, liver iron significantly increased from 1260 to 1937 µg/g_liver (P < 0·01), but serum ferritin remained stable at 2100 µg/l, as did the spleen iron concentration at 1200 µg/g_spleen. A two-compartment model may predict an average chelation efficacy for desferrioxamine and deferiprone, with a saturation effect of the latter, for a certain chelation and transfusion regimen by a single liver iron quantification.