Response to hydroxyurea in β thalassemia major and intermedia: Experience in western India

Abstract

Background The clinical and hematological response to hydroxyurea was evaluated in β thalassemia patients in western India with variable clinical severity and correlated with genetic factors. Materials and methods Seventy-nine patients-[38-β thalassemia intermedia-(group I), 41-β thalassemia major-(group II)] on hydroxyurea therapy were followed-up for 20–24 months. Results Among the frequently transfused patients in group I, 58% became transfusion independent and 16% showed a 50% reduction in transfusions after therapy which correlated with a higher mean fold increase in HbF and γ mRNA expression levels. Forty-one percent of patients in group I had associated α-thalassemia and 72.7% were XmnI (+/+). β thalassemia chromosomes among the responders of group I (41%) were linked to haplotype (− + + − + + − − +) as against haplotype (+ − − − − − − − +) being more common among the non-responders. Response was not linked to the β thalassemia mutations. Thirty-two percent of group II patients showed a 50% reduction in their transfusion requirements after therapy which also correlated with a higher mean fold increase in HbF and γ mRNA expression levels. A significant decrease in serum ferritin was seen in both groups. 19% of patients could not tolerate the drug. Conclusions In group I, clinical response to hydroxyurea was better in patients with α–thalassemia, XmnI (+/+) and a higher mean fold increase in γ mRNA expression. In group II, only one-third of patients showed a partial response.