A Study to Determine the Efficacy and Safety of Luspatercept in Adult Participants and to Evaluate the Safety and Pharmacokinetics in and Adolescent Participants With Alpha (α)-Thalassemia

Inclusion criteria

• . TD participant: ≥ 6 RBC units during the 24 weeks prior to randomization.
• . NTD participant:\< 6 RBC units during the 24 weeks prior to randomization(transfusion due to conditions other than A-Thal will not be considered)and, RBC transfusion-free during at least 8 weeks prior to randomization(unless transfusion was required to treat an acute medical condition other than A-Thal) and, mean baseline Hb ≤ 10 g/dL, based on a minimum of 2 measurements ≥ 1 week apart within 4 weeks prior to randomization; hemoglobin values within 21 days post-transfusion will be excluded.
• . TD participant: ≥ 4 RBC events during the 24 weeks prior to enrollment and, no transfusion-free period for \> 56 days during the 24 weeks prior to enrollment. Participants must have a history of regular transfusions for at least 2 years.
• . NTD participant:\< 4 RBC events during the 24 weeks prior to enrollment and RBC transfusion-free during at least 8 weeks prior to enrollment and, mean baseline Hb ≤ 10 g/dL, based on a minimum of 2 measurements ≥ 1 week apart within 4 weeks prior to enrollment, hemoglobin values within 21 days post-transfusion will be excluded.