An erythroid maturation defect causing ineffectibe erythropoiesis and red blood cell maturation is associated with the condition β-thalassemia. Luspatercept is a first-in-class erythroid maturation agent, which is under development for the treatment of this condition. Maria Domenica Cappellini, MD, of the University of Milan, Milan, Italy, presents here the results of the Phase III BELIEVE trial (NCT02604433) of luspatercept vs. a placebo in adults with β-thalassemia who require regular red blood cell transfusions. Excitingly, luspatercept significantly reduced transfusion burden and was generally well-tolerated.