Efficacy and Safety of Once-Daily, Oral Iron Chelator Deferasirox (Exjade^®) in a Large Group of Regularly Transfused Patients with β-Thalassemia Major

Background: The 1-year, prospective, multicenter EPIC trial, the largest ever conducted for an iron-chelating agent, evaluated the efficacy and safety of the once-daily, oral chelator deferasirox (Exjade^®) in patients (pts) with transfusion-dependent anemias. 54% of 1744 pts had β-thalassemia major, providing one of the largest data sets assessing the use of deferasirox in this group. Data from this subgroup are presented.

Methods: Pts (≥2 years old) with transfusional iron overload due to β-thalassemia and serum ferritin (SF) levels of ≥1000 ng/mL or <1000 ng/mL but with a history of multiple transfusions (>20 transfusions or 100 mL/kg of blood) and R2 MRI-confirmed liver iron concentration >2 mg Fe/g dry weight, received an initial deferasirox dose of 10–30 mg/kg/day dependent on transfusion requirements. Protocol-specified dose adjustments in steps of 5–10 mg/kg/day (range 0–40 mg/kg/day) were done every 3 months based on SF trends and safety markers. The change at week 52 from baseline (BL) was the primary efficacy endpoint.

Results: 937 pts with β-thalassemia major, 450 males and 487 females (mean age 18.4±10.8 years), were enrolled. Median BL SF was 3157 ng/mL (range 462–22320). In the year prior to enrollment, pts received a mean of 189.8 mL/kg of blood (range 0–1768). Most pts (n=625; 66.7%) had received deferoxamine (DFO); 234 (25.0%) DFO/deferiprone combination, 12 (1.3%) deferiprone alone and four (0.4%) other therapy; 66 (7.0%) were chelation naive. 798 pts (85%) started on ≤20 mg/kg/day and 139 (15%) on >20 mg/kg/day. 51% required a dose increase at a median of 24 weeks after treatment initiation (range 2–53). After 1 year, median SF significantly decreased from BL by 129 ng/mL (P=0.0007) at an average actual dose of 24.2±5.6 mg/kg/day. Pts receiving an average actual dose of ≥30 mg/kg/day achieved a significant reduction in SF at 1 year. Pts receiving an average actual dose of <20 or ≥20–<30 mg/kg/day maintained their iron balance. SF change by mean actual dose received is shown in Table 1. The magnitude of reduction in SF was reflective of dose adjustments throughout the study.

Table 1. Median change from BL in SF (ng/mL) by average actual dose received

Only 9.5% of pts (n=89) discontinued therapy. Reasons for withdrawal were AEs (n=31, 3.3%), consent withdrawal (n=24, 2.6%), unsatisfactory therapeutic effect (n=12, 1.3%), lost to follow-up (n=5, 0.5%), death (n=4, 0.4%, three due to cardiac failure and one to septicemia following surgery, none treatment related by investigators’ assessment) and other (n=13, 1.4%). The most common investigator-assessed drug-related AEs were rash (n=115, 12.3%), diarrhea (n=76, 8.1%) and abdominal pain (n=50, 5.3%). The majority of AEs were mild-to-moderate (>95%). Thirty-seven pts (3.9%) had serum creatinine >33% above BL and the upper limit of normal (ULN) on two consecutive visits; there were no progressive increases. Five (0.5%) pts had an increase in alanine aminotransferase >10×ULN on two consecutive visits; levels were already elevated in four pts.

Conclusions: These data confirm that in heavily iron-loaded pts with β-thalassemia major, higher deferasirox doses are needed to achieve significant reductions in SF, while lower doses are able to maintain iron balance. The starting dose guided by the rate of iron intake from blood transfusions and current iron burden should be titrated individually and promptly (at 3 months) according to SF trends and safety markers. Deferasirox treatment in this subgroup was generally well tolerated (including doses ≥30 mg/kg/day) with a low discontinuation rate.