Deferasirox (ICL670) is a once-daily oral iron chelator developed for the treatment of chronic iron overload from blood transfusions. A comparative phase 3 trial was conducted to demonstrate the efficacy of deferasirox in regularly transfused patients with -thalassemia aged 2 years or older. Patients were randomized and received treatment with deferasirox (n ؍ 296) or deferoxamine (n ؍ 290), with dosing of each according to baseline liver iron concentration (LIC). The primary endpoint was maintenance or reduction of LIC; secondary endpoints included safety and tolerability, change in serum ferritin level, and net body iron balance. In both arms, patients with LIC values of 7 mg Fe/g dry weight (dw) or higher had significant and similar dose-dependent reductions in LIC and serum ferritin, and effects on net body iron balance. However, the primary endpoint was not met in the overall population, possibly due to the fact that proportionally lower doses of deferasirox relative to deferoxamine were administered to patients with LIC values less than 7 mg Fe/g dw. The most common adverse events included rash, gastrointestinal disturbances, and mild nonprogressive increases in serum creatinine. No agranulocytosis, arthropathy, or growth failure was associated with deferasirox administration. Deferasirox is a promising once-daily oral therapy for the treatment of transfusional iron overload. (Blood. 2006;107:3455-3462)
Summary
Deferasirox is a once‐daily, oral iron chelator developed for treating transfusional iron overload. Preclinical studies indicated that the kidney was a potential target organ of toxicity. As patients with sickle cell disease often have abnormal baseline renal function, the primary objective of this randomised, open‐label, phase II trial was to evaluate the safety and tolerability of deferasirox in comparison with deferoxamine in this population. Assessment of efficacy, as measured by change in liver iron concentration (LIC) using biosusceptometry, was a secondary objective. A total of 195 adult and paediatric patients received deferasirox (n = 132) or deferoxamine (n = 63). Adverse events most commonly associated with deferasirox were mild, including transient nausea, vomiting, diarrhoea, abdominal pain and skin rash. Abnormal laboratory studies with deferasirox were occasionally associated with mild non‐progressive increases in serum creatinine and reversible elevations in liver function tests. Discontinuation rates from deferasirox (11·4%) and deferoxamine (11·1%) were similar. Over 1 year, similar dose‐dependent LIC reductions were observed with deferasirox and deferoxamine. Once‐daily oral deferasirox has acceptable tolerability and appears to have similar efficacy to deferoxamine in reducing iron burden in transfused patients with sickle cell disease.
Objectives ⁄ methods: This 1-yr prospective phase II trial evaluated the efficacy of deferasirox in regularly transfused patients aged 3-81 yrs with myelodysplastic syndromes (MDS; n = 47), Diamond-Blackfan anaemia (DBA; n = 30), other rare anaemias (n = 22) or b-thalassaemia (n = 85). Dosage was determined by baseline liver iron concentration (LIC). Results: In patients with baseline LIC ‡7 mg Fe ⁄ g dry weight, deferasirox initiated at 20 or 30 mg ⁄ kg ⁄ d produced statistically significant decreases in LIC (P < 0.001); these decreases were greatest in MDS and least in DBA. As chelation efficiency and iron excretion did not differ significantly between disease groups, the differences in LIC changes are consistent with mean transfusional iron intake (least in MDS: 0.28 ± 0.14 mg ⁄ kg ⁄ d; greatest in DBA: 0.4 ± 0.11 mg ⁄ kg ⁄ d). Overall, LIC changes were dependent on dose (P < 0.001) and transfusional iron intake (P < 0.01), but not statistically different between disease groups. Changes in serum ferritin and LIC were correlated irrespective of disease group (r = 0.59), supporting the potential use of serum ferritin for monitoring deferasirox therapy. Deferasirox had a safety profile compatible with long-term use. There were no disease-specific safety ⁄ tolerability effects: the most common adverse events were gastrointestinal disturbances, skin rash and non-progressive serum creatinine increases. Conclusions: Deferasirox is effective for reducing iron burden with a defined, clinically manageable safety profile in patients with various transfusion-dependent anaemias. There were no disease-specific adverse events. Once differences in transfusional iron intake are accounted for, dose-dependent changes in LIC or serum ferritin are similar in MDS and other disease groups.
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