The purpose of the study is to evaluate the efficacy and safety of luspatercept plus best supportive care (BSC) vs placebo plus BSC on anemia in adult participants with α-thalassemia hemoglobin H (HbH) disease and determine the safety and drug levels in adolescent participants.
Adult participant≥ 18 years with documented diagnosis of A-Thal HbH disease with Transfusion dependence defined as:.
Adult participant has Eastern Cooperative Oncology Group (ECOG) 34 score of 0 or 1.
Adolescent participant 12 years to < 18 years with documented diagnosis of A-Thal HbH disease with transfusion dependence defined as:.
Medical Conditions: Diagnosis of A-ThalTrait, Hb Bart hydrops, ATRx A-Thal, hemoglobin S/β-thalassemia, myelodysplasia subtype anemia, or with HbE homozygous beta gene mutation. Anemia related to nutritional deficiency, anemia of chronic disease, autoimmune hemolytic anemia, or any other hemolytic anemias. Undergone episodes of hemolysis not related to A-Thal within the 8 weeks prior to randomization. Applicable for the EU only: Bleeding disorders manifested by frequent bleeding episodes (eg, menorrhagia, epistaxis, clotting disorders).
Participant has deep vein thrombosis (DVT), stroke or other thromboembolic event(s) (except clogged indwelling catheter) requiring medical intervention ≤ 24weeks prior to randomization.
Participant has uncontrolled hypertension. Controlled hypertension for this protocol is considered: blood pressure value corresponding to ≤Grade 1 according to NCI CTCAE Version 5.0. with or without pharmacological treatment.
Reproductive Status: Women who are pregnant, plan to get pregnant during the study, or who are breastfeeding.