Effect of Hydroxyurea on the Level of Ineffective Erythropoiesis, Transfusion Requirement, and Fetal Hemoglobin Synthesis in Patients With Beta-Thalassemia-Intermedia

This 12-month study will evaluate the safety and effectiveness of hydroxyurea in treating beta-thalassemia, a type of anemia caused by defective hemoglobin (the oxygen-carrying pigment in blood). Hemoglobin is composed of two protein chains-alpha globin chains and beta globin chains; patients with beta-thalassemia do not make beta globin. Patients often require frequent red blood cell transfusions. This leads to iron overload, which, in turn, requires iron chelation therapy (removal of iron from the blood).

Some drugs, including hydroxyurea, can stimulate production of a third type of protein chain called gamma chains. In the womb, the fetus makes this type of protein instead of beta globin. It is not until after birth, when the fetus no longer produces gamma globin that the beta globin deficiency becomes apparent. Gamma chain synthesis improves hemoglobin and red blood cell production, correcting the anemia. This study will determine if and at what dose hydroxyurea treatment reduces patients' need for red blood cell transfusions and whether certain factors might predict which patients are likely benefit from this treatment.

Patients 15 years and older with moderately severe beta-thalassemia may be eligible for this study. Participants will take hydroxyurea daily at a dose calculated according to the patient's body size. Blood will be drawn weekly to measure blood cell and platelet counts. The drug dosage may be increased after 12 weeks of treatment and again after 24 weeks if the white cell and platelet counts remain stable. Patients who respond dramatically to treatment may continue to receive hydroxyurea for up to 3 years.