Hydroxyurea (HU) is one of several agents that have been shown to enhance
hemoglobin (Hb) F levels in patients with
sickle cell disease and may be useful as a
therapy for beta-globinopathies. However, limited information exists on the effects of HU in patients with
thalassemia. Accordingly, we examined the hematologic effects of orally administered HU in 13 patients with
beta-thalassemia/Hb E, including four patients who had been splenectomized. These patients were treated with escalating doses (final range, 10 to 20 mg/kg/d) for 5 months and were observed in the outpatient hematology clinic every 2 to 4 weeks. Complete blood counts including reticulocyte counts, amounts of Hb E and Hb F, G
gamma:A gamma and alpha:non-
alpha globin biosynthetic ratios were evaluated before and during treatment. Almost all patients responded with an average increase of 33% in Hb F levels, from a mean (+/- SD) of 42% +/- 11% to 56% +/- 8% (P < .0001), and a reciprocal decline in the percentage of Hb E from 59% +/- 9% to 49% +/- 8% (P < .001).
Reticulocytosis was decreased from a mean (+/- SD) of 18.0% +/- 15.6% to 11.7% +/- 9.1% (P < .05); there was also a slight (10%) but statistically significant increase in
hemoglobin levels and an improved balance in alpha:non-
alpha globin chains ratios. The side effects were minimal in most patients, although these patients tended to tolerate a lower dose of HU before significant myelosuppression than has been our previous experience in
sickle cell disease. One splenectomized patient died of
sepsis during the trial. We conclude that increased Hb F production in
beta-thalassemia/Hb E patients, with an improvement in the alpha:non-
alpha globin ratios and, probably, the effectiveness of erythropoiesis, can be achieved using HU. Longer trials of HU in this population, including at other doses and in combination with other agents, appear warranted.