Progress in hematopoietic stem cell transplantation as allogeneic cellular gene therapy in thalassemia.

Allogeneic hemopoietic stem cell transplantation (HSCT) represents one of the best cures for thalassemia. Currently, HSCT for thalassemia consists of allogeneic stem cell gene therapy and still awaits autologous genetically modified stem cell transplantation. HSCT for thalassemia has substantially improved over the last two decades, due in large part to improvements in preventive strategies, the effective control of transplant-related complications, and the development of new preparative regimens. A risk classes-based approach to transplantation in thalassemia has led to disease-free survival probability of 87, 85, and 80% in classes 1, 2, and 3 patients, respectively. Adult thalassemia patients, who are higher risk patients for transplant-related toxicity due to an advanced phase of the disease, have a cure rate of 65% with current treatment protocol. Patients who do not have matched family or unrelated donors could benefit from haploidentical mother-to-child transplantation. Overall, the results of this type of transplantation appear encouraging.