Hydroxyurea-induced hematological response in transfusion-independent beta-thalassemia intermedia: case series and review of literature.

Hydroxyurea (HU) may improve the symptoms in thalassemia patients by increasing gamma-globin chain expression. However, the efficacy of HU in beta-thalassemia intermedia (TI) is unclear. The authors treated 16 transfusion-independent TI patients (8 males) aged 10.7 +/- 5.0 years with HU, 20 mg/kg/day 4 days per week, for 6 months. Hemoglobin (Hb) and HbF levels were measured prior to treatment, during the treatment period (monthly), and following the completion of treatment. Mutations in the beta-globin gene as well as the XmnI polymorphism were determined. Treatment was well tolerated. There was a significant increase in both Hb and HbF (p < .001), and the increments were strongly correlated (r = .94; p < .001). XmnI polymorphism was not correlated with hematological response. Hb (p = .026) and HbF (p = .046) showed a more significant rise in patients with a Fr8/9 allele than those with one or two IVS-II-1 alleles. HU therapy was associated with a significant hematological response in our TI patients. The Fr8/9 mutation, but not the XmnI polymorphism, was a predictor of good hematological response. Studies with larger sample sizes are needed to confirm the results obtained in this study.