One-year results from a prospective randomized trial comparing phlebotomy with deferasirox for the treatment of iron overload in pediatric patients with thalassemia major following curative stem cell transplantation

Abstract

Background: Iron overload is well documented in patients with β-thalassemia major, and patients who have undergone hematopoietic stem cell transplantation (HSCT) remain at risk as a result of pre- and immediate post-HSCT transfusions.

Procedure: This is a prospective, randomized, 1-year clinical trial that compares the efficacy and safety of the once-daily oral iron chelator deferasirox versus phlebotomy for the treatment of iron overload in children with β-thalassemia major following HSCT.

Results: Patients (aged 12.4 years) received deferasirox (n = 12, 10 mg/kg/day starting dose) or phlebotomy (n = 14, 6 ml/kg/2 weeks) for 1 year. In two and five patients, deferasirox dose was increased to 15 and 20 mg/kg/day, respectively. Magnetic resonance imaging (MRI)-assessed liver iron concentration (LIC) decreased with deferasirox (mean 12.5 ± 10.1 to 8.5 ± 9.3 mg Fe/g dry weight [dw]; P = 0.0005 vs. baseline) and phlebotomy (10.2 ± 6.8 to 8.3 ± 9.2 mg Fe/g dw; P = 0.05). LIC reductions were greater with deferasirox than with phlebotomy for patients with baseline serum ferritin 1,000 ng/ml or higher (-8.1 ± 1.5 vs. -3.5 ± 5.7 mg Fe/g dw; P = 0.048). Serum ferritin and non-transferrin-bound iron also decreased significantly. In two patients with severe cardiac siderosis, a clinically relevant improvement in myocardial T2* was seen, following phlebotomy and deferasirox therapy (n = 1 each). Adverse effects with deferasirox were skin rash, gastrointestinal upset, and increased liver function tests (all n = 1), while those for phlebotomy were difficulty with venous access (n = 4) and distress during procedure (n = 1). Parents of 13/14 children receiving phlebotomy wished to switch to deferasirox, with 1/14 being satisfied with phlebotomy.

Conclusions: Deferasirox treatment or phlebotomy reduces iron burden in pediatric patients with β- thalassemia major post-HSCT, with a manageable safety profile.

Keywords: deferasirox; hematopoietic stem cell transplant; phlebotomy; randomized controlled trial; thalassemia.