Beyond transfusion therapy: new therapies in thalassemia including drugs, alternate donor transplant, and gene therapy

Abstract

Abstract Transfusion combined with chelation therapy for severe β thalassemia syndromes (transfusion-dependent thalassemia [TDT]) has been successful in extending life expectancy, decreasing comorbidities and improving quality of life. However, this puts lifelong demands not only on the patients but also on the health care systems that are tasked with delivering long-term treatment and comprehensive support. Prevention programs and curative approaches are therefore an important part of overall strategy. Curative treatments alter the dynamic of a patient's health care costs, from financial commitment over 50 years, into a potential “one-off” investment. Since the 1980s, this has usually been available only to the 30% or so of young children with matched sibling donors. By improving the safety of matched related donors and haploidentical hematopoietic stem cell transplants, the potential size of the donor pool for curative therapies may be increased. Recent advances in gene therapy demonstrate that even patients lacking a matched donor can be rendered transfusion independent with an autograft of genetically modified autologous stem cells, with a low short-term risk. Noncurative treatments are also of potential value by decreasing use of blood and chelators and decreasing hospital visits. An example is luspatercept, an activin-receptor trap that modifies transforming growth factor-β signaling, thereby increasing the efficiency of erythropoiesis. This has entered phase 3 clinical trials for TDT and non-TDT and, usefully increases in both Hb and quality of life in non-TDT as well as decreasing transfusion requirements in TDT. Other novel noncurative treatments are entering clinical trials such improvement of erythropoiesis through pharmacological manipulation of hepcidin and iron metabolism.