Deferasirox for the Treatment of Transfusional Iron Overload In Sickle Cell Anemia: a 2-Yr Prospective Study

Majority of patients with sickle cell disease receive repeated blood transfusions by adulthood. Because the body has no physiological mechanism to actively excrete excess iron, chelation therapy is important for the management of iron overload and its complications, including iron deposition into the liver, heart and endocrine organs, eventual death. Deferasirox (DFX) is a once-daily, oral iron chelator that is approved as first-line treatment of chronic transfusional iron overload. Its safety, tolerability and efficacy in reducing body iron burden have been demonstrated in patients with β-thalassaemia major and in other chronic transfusion-dependent anaemias, including SCD.

Objectives of this prospective, non-randomised, phase IV trial were to evaluate the iron overload status, before and after two year-treatment with DFX, using liver iron concentration [LIC, mg/d dry weight (dw)] by magnetic resonance imaging (MRI) hepatic, MRI cardiac (Cardiac T2*, ms), serum ferritin (SF, μ g/L), and to evaluate the safety and tolerability of DFX.

A total of 31 patients with SCD and iron overload, defined as the use of ≥ 20 units of RBC units and/or two SF levels ≥ 1000 μ g/L during the 6 months preceding enrollment, received starting dose of 20mg/kg/day of DFX. Efficacy was assessed monthly by measuring change from baseline in SF levels. Safety was evaluated on a monthly basis according to the incidence and type of adverse events and measurement of laboratory parameters, including serum creatinine and liver enzyme levels. Two patients discontinued treatment at 8 and 9 months, due to pregnancy and moving to other city, respectively. One patient died at 18 months due to pulmonary infection and hemorrhagic stroke. DFX was interrupted in 3 patients due to confirmed SF levels <500 μ g/L at 18-month period of treatment and DFX was not reinstated in none of them during the final 6 months of study. Twenty-five patients completed 2-year treatment. Mean ± SD age 26.9 ± 12.5y; 84% female, 90% afrodescendent, 61.3% on regular blood transfusion; median (range) DFX dose over 24 months and DFX exposure were 20 mg/kg/day (15-25) and 90.5 weeks (35.6-98.0), respectively. Mean SF level (μ g/L) did not significantly reduced at 12 months (p=0.052) but significantly dropped at 24 months compared to baseline [from 2344.6 to 1986.3 (p=0.040)]. Mean ± SD LIC significantly dropped at 12 months and at 24 months compared to baseline [from 13.0 ± 5.4 to 10.4 ± 6.3 (p=0.001) and to 9.3 ± 5.7 (p<0.001), respectively]. The proportion of patients with LIC levels (mg/g dw) ≤7.0, >7.0- ≤14.0 and >14.0 from baseline to 24 months by percentage of patients changed from 13.6% to 44.0%, 40.9% to 44.0% and 45.5% to 12.0%, respectively. In all patients, Cardiac T2* was normal (> 20 ms) at baseline, 12 and 24 months of treatment. There was no significant difference between left ventricular ejection fraction values at baseline and after 12 months but this parameter significantly increased at 24 months of treatment compared to baseline [from 62.2 ± 6.0 to 64.6 ± 6.2 (p=0.02)]. The most common drug-related AEs were mild, transient diarrhea (7 pts), headache (7), nausea (5), vomiting (3), skin rash (2), increases in ALT (2), serum creatinine increases that exceeded the ULN (2). No patient experienced progressive increases in serum creatinine or renal failure.

Our data confirms that deferasirox is effective in reducing body iron burden in transfused patients with SCD, well tolerated in pediatric and adult patients and with a clinically manageable safety profile. The availability of deferasirox as a once-daily, oral iron chelator would potentially facilitate improved compliance, and thereby reduce morbidity and mortality from iron overload.

No relevant conflicts of interest to declare.