Abstract
Iron overload is a potentially life-threatening consequence of multiple blood transfusions. Effective iron chelation therapy reduces morbidity and saves lives. Many patients are unable to comply with current treatments, deferoxamine (DFO) or deferiprone (L1), because they cannot tolerate the parenteral infusion regimen required for DFO, because of adverse events (AEs), or because they do not respond to treatment. The objective of the ESCALATOR trial is to evaluate the effectiveness of deferasirox, an investigational once-daily oral iron chelator in advanced clinical development, in reducing liver iron concentration (LIC) in patients with β-thalassemia unable to be properly treated with DFO and/or L1. During a 1-year treatment period, patients will receive deferasirox at a daily dose of 20 mg/kg. Reduction of LIC is the primary endpoint, as assessed by biopsy at baseline and study end. Secondary efficacy variables include serum ferritin (SF) and other potential surrogate markers of iron overload such as concentration of labile plasma iron (LPI) in a subgroup of patients. Safety assessments include AEs and comprehensive laboratory evaluations. To date, 232 patients have initiated treatment at seven centers in five countries (Egypt, Saudi Arabia, Lebanon, Oman, Syria). Demographics, relevant medical history and baseline iron burden parameters are described in the table. Importantly, baseline SF values were significantly correlated with LIC (R=0.63; P<0.0001). The last patient’s last visit will be in June 2006.
Age 2 to <16 years (n=159) Age ≥16 years (n=73) All patients (n=232) Mean ± SD; †n=14 Female:male, n 79:80 35:38 114:118 Race (caucasian:oriental:other), n 59:81:19 11:41:21 70:122:40 BMI*, kg/m2 17.4 ± 2.6 21.6 ± 3.2 18.7 ± 3.4 Weight*, kg 29.4 ± 9.9 54.7 ± 9.7 37.3 ± 15.3 Hepatitis B or C, n 43 29 72 Splenectomy, n 46 53 99 Transfusions in previous year*, n 15.5 ± 4.5 14.3 ± 3.7 15.1 ± 4.3 Total volume transfused in previous year*, mL 5265 ± 2469 7446 ± 2953 5873 ± 2784 Years on chelation therapy*, n 6.2 ± 3.5 12.7 ± 4.8 8.2 ± 4.9 Proportion of life on transfusion therapy*, % 89.3 ± 13.9 89.0 ± 14.1 89.2 ± 14.0 Liver pathology grading (modified HAI scale) Grade 0–6 143 64 207 Grade 7–12 4 0 4 Grade 13–18 0 0 0 LIC, mg Fe/g dw Mean ± SD 17.1 ± 8.5 20.0 ± 10.0 18.0 ± 9.1 Median (min, max) 16.6 (2.9, 38.2) 19.0 (2.9, 48.9) 17.5 (2.9, 48.9) SF, ng/mL Mean ± SD 3957 ± 2342 4564 ± 4117 4148 ± 3019 Median (min, max) 3356 (914, 13539) 3335 (956, 23017) 3346 (914, 23017) LPI†,μmol/L Mean ± SD - - 1.03 ± 0.80 Median (min, max) - - 0.82 (0, 2.65)
The ESCALATOR study cohort is a highly challenging population with varied chelation response and transfusion history. The magnitude of LIC and SF, which were well correlated, reflects the severity of iron overload in patients unable to maintain adequate chelation using DFO or L1. This study will provide important insights into the clinical management of iron overload with the well tolerated, once-daily oral iron chelator deferasirox in this difficult-to-treat population.
Thalassemia Management Checklists: Quick Reference Guides to Reduce Disparities in the Care of Patients with Transfusion-Dependent Thalassemia
