Response to hydroxyurea in beta thalassemia major and intermedia: experience in western India

The clinical and hematological response to hydroxyurea was evaluated in beta thalassemia patients in western India with variable clinical severity and correlated with genetic factors.

Seventy-nine patients-[38-beta thalassemia intermedia-(group I), 41-beta thalassemia major-(group II)] on hydroxyurea therapy were followed-up for 20-24months.

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 gamma mRNA expression levels. Forty-one percent of patients in group I had associated alpha-thalassemia and 72.7% were XmnI (+/+). beta 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 beta 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 gamma mRNA expression levels. A significant decrease in serum ferritin was seen in both groups. 19% of patients could not tolerate the drug.

In group I, clinical response to hydroxyurea was better in patients with alpha-thalassemia, XmnI (+/+) and a higher mean fold increase in gamma mRNA expression. In group II, only one-third of patients showed a partial response.