Hematopoietic stem cell transplantation for people with ß-thalassaemia major.

Background: Thalassemia is an inherited blood disorder, caused by mutations in regulatory genes and transmitted as an autosomal recessive disorder, which results in a reduced rate of synthesis of one of the globin chains that make up haemoglobin. In ß-thalassaemia major there is an underproduction of ß-globin chains combined with excess of free α-globin chains. The excess free α-globin chains damage the red blood cell membranes, leading to their destruction and a phenomenon termed ineffective erythropoiesis. The conventional approach to treatment is based on the correction of haemoglobin status through regular blood transfusions and iron chelation therapy for iron overload. Although conventional treatment has the capacity to improve the quality of life of people with ß-thalassaemia major, allogeneic hematopoietic stem cell transplantation is the only currently available procedure which has the potential to definitively cure the disease.

Objectives: To evaluate the effectiveness and safety of different types of allogeneic hematopoietic stem cell transplantation, in people with severe transfusion-dependant ß-thalassaemia major, ß-thalassaemia intermedia or ß0/+- thalassaemia variants requiring chronic blood transfusion.

Search Methods: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings.Date of the most recent search: 11 November 2013.

Selection Criteria: Randomised controlled trials and quasi-randomised controlled trials comparing allogeneic hematopoietic stem cell transplantation with each other or with standard therapy (regular transfusion and chelation regimen).

Data Collection And Analysis: Two review authors independently screened studies and had planned to extract data and assess risk of bias using standard Cochrane Collaboration methodologies but no studies were identified for inclusion.

Main Results: No relevant studies were retrieved after a comprehensive search of the literature.

Authors' Conclusions: We were unable to identify any randomised controlled trials or quasi-randomised controlled trials on the effectiveness and safety of different types of allogeneic stem cell transplantation in people with severe transfusion-dependant ß-thalassaemia major or ß0/+- thalassaemia variants requiring chronic blood transfusion. The absence of high-level evidence for the effectiveness of these interventions emphasises the need for well-designed, adequately-powered, randomised controlled clinical trials.