Treatment with Deferasirox Effectively Decreases Iron Burden in Patients with Sickle Cell Disease and Thalassemia Intermedia.

Abstract 1517

Poster Board I-540

Iron overload was not thought to be an important issue in sickle cell disease (SCD) in the past because of the short life-span of SCD patients. However, the increase in longevity during the recent years has been associated with clinical evidence of iron overload in some SCD patients due to accumulation of transfusional iron, increased absorption associated with intensive erythropoiesis and iron deposition as a result of continuous hemolysis. Therefore, iron overload may play an important role in the severity of SCD and iron chelation has a definite indication in several SCD cases. Thalassemia intermedia (TI) encompasses a wide clinical spectrum of beta-thalassemia phenotypes. Iron overload is alsofrequently present in TI patients as a result of increased intestinal iron absorption secondary to chronic anemia and to sporadic blood transfusion therapy, which may be administered intermittently when hemoglobin (Hb) levels fall <7 g/dL. Thus, a variable rate of iron loading, reaching toxic levels in some patients, was seen in a series of intermittently transfused TI patients who need adequate chelation therapy. Deferasirox (Exjade^®) is a once-daily orally administered iron chelator approved for the treatment of transfusional iron overload in patients with transfusion-dependent anemia. Here, we report on the efficacy and safety of deferasirox in iron-overloaded patients with SCD and TI. We evaluated 18 adult patients with SCD (8M/10F; mean age 41.3 ± 8.5 years) and 11 with TI (5M/6F; mean age 41.2 ± 6.5 years) who had serum ferritin levels >1000 ng/mL and who were sporadically transfused with <20 units of red blood cells before starting deferasirox treatment for up to 12 months. Twenty-four patients (15 with SCD and 9 with TI) and 5 (3 with SCD and 2 with TI) patients were initially treated with deferasirox at 10 and 20 mg/kg/day, respectively, based on the number of blood transfusions received before the initiation of treatment. After 3 months, dose adjustments (increases) were allowed in increments of 5 mg/kg/day every 3 months as required to reduce markers of iron overload. Total iron burden was monitored by measuring serum ferritin levels before and monthly after starting deferasirox, while liver iron concentration and cardiac iron burden were measured by magnetic resonance imaging (MRI) T2 and T2* parameters at baseline and 12 months after deferasirox treatment. Left ventricular ejection fraction (LVEF) by MRI, and 24-hour proteinurea (Prot 24h) before and after treatment, were also measured. Hb levels, serum creatinine, cystatin-C (a sensitive marker of renal impairment), alanine (ALT) and aspartate aminotransferase (AST) were measured before and every month during deferasirox treatment. Serum ferritin level was significantly reduced after 12 months of deferasirox treatment in both SCD (mean±SD: from 1993±997 ng/ml to 1106±1016 ng/ml, p<0.001) and TI patients (from 2030±1040 ng/ml to 1165±684 ng/ml, p=0.02). Similarly baseline liver T2 and T2* significantly increased following 12 months of therapy in SCD (from 21.1±5.7 ms to 27.4±8.0 ms, p=0.001 and from 4.1±3.8 ms to 6.0±3.4 ms, p=0.013, for T2 and T2* respectively) and TI patients (from 20.1±4.1 ms to 23.7±6.2 ms, p=0.01 and from 3.4±3.0 ms to 4.4±3.0 ms, p=0.02, for T2 and T2* respectively). Mean cardiac T2* and LVEF were normal at baseline and did not significantly change after 12 months of treatment in SCD and TI patients. There were also no significant changes in mean serum creatinine, Hb or Prot 24h levels after 12 months of deferasirox treatment, while mean ALT and AST levels significantly decreased over 12 months in both groups of patients (p<0.02 and p<0.04 for SCD and TI, respectively). In terms of cystatin-C, there was a significant increase after 12 months of treatment in SCD patients (from 0.97±0.32 mg/l to 1.12±0.4 mg/l, p<0.001) but not in TI patients, in whom the increase was of borderline significance (from 0.98±0.23 mg/l to 1.13±0.27 mg/l, p=0.094). These data indicate that, over 12 months, deferasirox significantly reduced liver iron burden and serum ferritin levels in these iron-overloaded patients with SCD and TI. The decreases in ALT and AST are suggestive of an improvement in liver function, while there must be some caution for renal impairment, mainly in SCD. This study indicates that deferasirox provides effective iron chelation therapy in these patients without any significant adverse effects.