A randomised double-blind placebo-controlled clinical trial of oral hydroxyurea for transfusion-dependent ß-thalassaemia.

Hydroxyurea is an antimetabolite drug that induces fetal haemoglobin in sickle cell disease. However, its clinical usefulness in ß-thalassaemia is unproven. We conducted a randomised, double-blind, placebo-controlled clinical trial to evaluate the efficacy and safety of hydroxyurea in transfusion-dependent ß-thalassaemia. Sixty patients were assigned 1:1 to oral hydroxyurea 10-20 mg/kg/day or placebo for 6 months by stratified block randomisation. Hydroxyurea treatment did not alter the blood transfusion volume overall. However, a significantly higher proportion of patients on hydroxyurea showed increases in fetal haemoglobin percentage (89% vs. 59%; p < 0.05) and reductions in erythropoietic stress as measured by soluble transferrin receptor concentration (79% vs. 40%; p < 0.05). Based on fetal haemoglobin induction (> 1.5%), 44% of patients were identified as hydroxyurea-responders. Hydroxyurea-responders, required significantly lower blood volume (77 ± SD27ml/kg) compared to hydroxyurea-non-responders (108 ± SD24ml/kg; p < 0.01) and placebo-receivers (102 ± 28ml/kg; p < 0.05). Response to hydroxyurea was significantly higher in patients with HbE ß-thalassaemia genotype (50% vs. 0%; p < 0.01) and Xmn1 polymorphism of the γ-globin gene (67% vs. 27%; p < 0.05). We conclude that oral hydroxyurea increased fetal haemoglobin percentage and reduced erythropoietic stress of ineffective erythropoiesis in patients with transfusion-dependent ß-thalassaemia. Hydroxyurea reduced the transfusion burden in approximately 40% of patients. Response to hydroxyurea was higher in patients with HbE ß-thalassaemia genotype and Xmn1 polymorphism of the γ-globin gene.

Efficacy and safety of oral hydroxyurea in transfusion-dependent ß-thalassaemia: a protocol for randomised double-blind controlled clinical trial.

INTRODUCTION: Despite being one of the first diseases to be genetically characterised, ß-thalassaemia remains a disorder without a cure in a majority of patients. Most patients with ß-thalassaemia receive only supportive treatment and therefore have a poor quality of life and shorter life spans. Hydroxyurea, which has shown to induce fetal haemoglobin synthesis in human erythroid cells, is currently recommended for the treatment of sickle cell disease. However, its clinical usefulness in transfusion-dependent ß-thalassaemia is unclear. Here, we present a protocol for a randomised double-blind controlled clinical trial to evaluate the efficacy and safety of oral hydroxyurea in transfusion-dependent ß-thalassaemia. METHODS AND ANALYSIS: This single-centre randomised double-blind placebo-controlled clinical trial is conducted at the Thalassaemia Centre of Colombo North Teaching Hospital, Ragama, Sri Lanka. Adult and adolescent patients with haematologically and genetically confirmed transfusion-dependent ß-thalassaemia are enrolled and randomised into the intervention or control group. The intervention group receives oral hydroxyurea 10-20 mg/kg daily for 6 months, while the control group receives a placebo which is identical in size, shape and colour to hydroxyurea without its active ingredient. Transfused blood volume, pretransfusion haemoglobin level, fetal haemoglobin percentage and adverse effects of treatment are monitored during treatment and 6 months post-treatment. Cessation or reduction of blood transfusions during the treatment period will be the primary outcome measure. The statistical analysis will be based on intention to treat. ETHICS AND DISSEMINATION: Ethical approval has been obtained from the Ethics Committee of Faculty of Medicine, University of Kelaniya (P/116/05/2018) and the trial is approved by the National Medicinal Regulatory Authority of Sri Lanka. Results of the trial will be disseminated in scientific publications in reputed journals. TRIAL REGISTRATION NUMBER: SLCTR/2018/024; Pre-results.

Blood transfusion therapy for ß-thalassemia major and hemoglobin E ß-thalassemia: Adequacy, trends, and determinants in Sri Lanka.

BACKGROUND: Regular blood transfusion therapy still remains the cornerstone in the management of ß-thalassemia. Although recommendations are clear for patients with ß-thalassemia major, uniform transfusion guidelines are lacking for patients with hemoglobin E ß-thalassemia. In this study, we aim to describe the adequacy, trends, and determinants of blood transfusion therapy in a large cohort of pediatric patients with ß-thalassemia major and hemoglobin E ß-thalassemia. METHODS/PROCEDURE: This cross-sectional study was performed among all regularly transfused patents with ß-thalassemia aged 2 to 18 years attending three large thalassemia centers in Sri Lanka. Data were collected using an interviewer-administered questionnaire, perusal of clinical records, and physical examination of patients by trained doctors. RESULTS: A total of 328 patients (male 47%) were recruited; 83% had ß-thalassemia major, whereas 16% had hemoglobin E ß-thalassemia. Sixty-one percent of patients had low pretransfusion hemoglobin levels (< 9.0 g/dL) despite receiving high transfusion volumes (> 200 mL/kg/year) by a majority (56%). Median pretransfusion hemoglobin was significantly lower in patients with hemoglobin E ß-thalassemia compared with ß-thalassemia major (P < 0.001); however, there was no difference in requirement for high transfusion volumes over 200 mL/kg/year in both groups (P = 0.14). Hepatomegaly and splenomegaly were more common in hemoglobin E ß-thalassemia and were associated with lower pretransfusion hemoglobin. Transfusion requirements were higher among patients with hepatitis C and in those who are underweight. CONCLUSIONS: Over 60% of regularly transfused patients with ß-thalassemia have low pretransfusion hemoglobin levels despite receiving large transfusion volumes. Patients with hemoglobin E ß-thalassemia are undertransfused and specific recommendations should be developed to guide transfusions in these patients.