Hydroxyurea Use in Lebanese Patients With [beta]-Thalassemia Intermedia

Abstract

We read with great interest the recent paper by Karimi et al 1 describing the safety and efficacy of hydroxyurea (HU) in reducing complications of extramedullary hemopoiesis as well as increasing Hb levels in Iranian patients with thalassemia intermedia. This prompted us to report our findings on the use of HU in seven Lebanese patients with [beta]-thalassemia intermedia. Seven patients with [beta]-thalassemia intermedia received oral HU (10-20 mg/kg/d); the mean duration of therapy was 17.4 (range 6-46) months. Complete blood counts, liver enzymes, and serum creatinine levels were evaluated before and during HU. We defined therapy to be effective if there was an increase in Hb of at least 1 g/dL because this was correlated in other studies with symptomatic improvement. Hb rise was evaluated at 6 months and at the end of therapy. Toxicity was divided into hepatic and hematologic. Hematologic toxicity was defined as a decrease in the absolute neutrophil count to below 1.5 × 103/mm3 or a decrease in the platelet count to below 100 × 103. Hepatic toxicity was considered as an increase in liver function tests to least twice the upper normal values. Patient characteristics and results are summarized in Table 1. Only patients 4 and 7 had an increase in Hb of 1.7 and 3 g/dL, respectively, at 6 months. The rise in Hb was not sustained in patient 4. Patient 5 had an increase in Hb by 1.3 g/dL at month 10, but it decreased back by 0.6 g/dL at month 13. All other patients did not respond to HU. No significant toxicity was reported in our patients. Graphic Table 1 These findings are in contrast to the findings of Karimi et al. The difference in response to HU between Lebanese and Iranian patients could be due to the heterogenous nature of the disease, resulting from different mutations, and the association between the types of mutations and the response to HU. Other contributing factors may include the differences in the dosages of HU administered, noncompliance with drug therapy, tachyphylaxis to HU effect, the metabolism of the drug, and the small number of patients in our study. Because limited data are available on this subject, more studies in different ethnic groups are required