Phase II clinical evaluation of deferasirox, a once-daily oral chelating agent, in pediatric patients with beta-thalassemia major.

BACKGROUND AND OBJECTIVES: Deferasirox (ICL670) is a novel once-daily oral iron chelator developed for the treatment of chronic iron overload from blood transfusions. This study evaluated the safety and tolerability of deferasirox in pediatric patients with transfusion-dependent beta-thalassemia major. Efficacy and pharmacokinetic assessments were secondary objectives. DESIGN AND METHODS: Forty patients equally stratified into two age groups--children (2 to <12 years) and adolescents (12-17 years)--were treated with deferasirox for 48 weeks. All received once-daily deferasirox 10 mg/kg/day with modifications allowed after 12 weeks' treatment. Safety, liver iron concentration (LIC), serum ferritin and pharmacokinetics were assessed. RESULTS: Thirty-nine patients completed the study. One withdrew due to a skin rash. Adverse events were typical of this population, but only four were considered related to the study drug: mild nausea (two adolescents) and moderate skin rash (two children). There were no serious adverse events related to the study drug. Five patients briefly interrupted treatment due to elevated transaminases with no recurrences when treatment resumed. The mean deferasirox dose was 11.3 mg/kg/day. Overall LIC increased gradually from week 12 as mean daily iron intake was higher than excretion. Steady-state plasma levels of deferasirox and its iron complex, Fe-[deferasirox]2, were comparable between children and adolescents. INTERPRETATION AND CONCLUSIONS: Deferasirox was well tolerated by this pediatric population. Toxicities known to be associated with other commercially available iron chelators were not observed. The dose employed was too low to induce a net negative iron balance in this regularly transfused population. Pharmacokinetic data support a once-daily dosing regimen based on body weight.

Randomized phase II trial of deferasirox (Exjade, ICL670), a once-daily, orally-administered iron chelator, in comparison to deferoxamine in thalassemia patients with transfusional iron overload.

BACKGROUND AND OBJECTIVES: Iron accumulation is an inevitable consequence of chronic blood transfusions and results in serious complications in the absence of chelation treatment to remove excess iron. Deferoxamine (Desferal, DFO) reduces morbidity and mortality although the administration schedule of slow, parenteral infusions several days each week limits compliance and negatively affects long-term outcome. Deferasirox (Exjade, ICL670) is an oral chelator with high iron-binding potency and selectivity. In a phase II study, the tolerability and efficacy of deferasirox were compared with those of DFO in 71 adults with transfusional hemosiderosis. DESIGN AND METHODS: Patients were randomized to receive once-daily deferasirox (10 or 20 mg/kg; n=24 in both groups) or DFO (40 mg/kg, 5 days/week; n=23) for 48 weeks. Results. Both treatments were well tolerated and no patient discontinued deferasirox due to drug-related adverse events. The reported frequency of transient, mild to moderate gastrointestinal disturbances was higher in the deferasirox group than in the DFO group, but these disturbances settled spontaneously without dose interruption in all patients. Decreases in liver iron concentration (LIC) were comparable in the deferasirox 20 mg/kg/day and DFO groups; baseline values of 8.5 and 7.9 mg Fe/g dw fell to 6.6 and 5.9 mg Fe/g dw, respectively, by week 48. Deferasirox showed a plasma elimination half-life of 8-16 hours, supporting its once-daily administration. INTERPRETATION AND CONCLUSIONS: Deferasirox at daily doses of 10 or 20 mg/kg was well tolerated and, at 20 mg/kg, showed similar efficacy to DFO 40 mg/kg in terms of decreases in LIC.