: The presence of any of the following will exclude a participant from enrollment into the study: 1. Participant has any significant medical condition, laboratory abnormality, or psychiatric illness that would prevent the participant from participating in the study. 2. Participant has any condition including the presence of laboratory abnormalities, which places the participant at unacceptable risk if he/she were to participate in the study. 3. Participant has any condition that confounds the ability to interpret data from the study. 4. Participant has a diagnosis of Hemoglobin S/β-thalassemia or alpha (α)-thalassemia (eg, Hemoglobin H); β-thalassemia combined with α-thalassemia is allowed. 5. Participant has of active hepatitis C (HCV) infection, as demonstrated by a positive HCF-ribonucleic acid (RNS) test of sufficient sensitivity, or active infectious hepatitis B (as demonstrated by the presence of hepatitis B surface antigen (HBsAG) and/or hepatitis B virus (HBV)-deoxyribonucleic acid (DNA) positive, or known positive human immunodeficiency virus (HIV). Note: Participants receiving antiviral therapies should have 2 negative HCV-RNA tests 3 months apart before ICF/IAF signature, ie, one test at the end of the antiviral therapy and the second test 3 months following the first test. 6. Participant has severe infection ≤ 28 days prior to enrollment. Additionally, in the case of prior SARS-CoV-2 infection, symptoms must have completely resolved, and based on Investigator assessment in consultation with the Clinical Trial Physician, there are no sequelae that would place the participant at a higher risk of receiving investigational treatment. 7. Participant has received a live COVID-19 vaccine ≤ 28 days prior to screening. 8. Participant has deep vein thrombosis (DVT), stroke, or other thromboembolic event(s) (except clogged indwelling catheter) requiring medical intervention ≤ 24 weeks prior to enrollment. 9. Participant has chronic anticoagulant therapy ≤ 28 days prior to enrollment (Anticoagulant therapies used for prophylaxis for surgery or high-risk procedures as well as low molecular weight [LMW] heparin for superficial vein thrombosis [SVT] and chronic aspirin are allowed). 10. Participant has platelet count > 1000 x 109/L. 11. Participant has poorly controlled diabetes mellitus within 24 weeks prior to enrollment as defined by short term (eg, hyperosmolar or ketoacidotic crisis) and/or history of diabetic cardiovascular complications (eg, stroke or myocardial infarction). 12. Participant has treatment with another investigational drug or device ≤ 28 days prior to enrollment. 13. Participant has prior exposure to sotatercept (ACE-011) or luspatercept (ACE-536). 14. Participant underwent or is scheduled for HSCT or gene therapy 15. Participant has used an erythropoiesis-stimulating agent (ESA) ≤ 24 weeks prior to enrollment. 16. Participant use of iron chelation therapy (ICT), if initiated ≤ 8 weeks prior to enrollment (allowed if initiated > 8 weeks before or during treatment). 17. Participant use of hydroxyurea treatment ≤ 24 weeks prior to enrollment. 18. Participant is pregnant or breastfeeding female. 19. Participant has uncontrolled hypertension. Controlled hypertension for this protocol is considered ≤ Grade 1 according to NCI CTCAE version 5.0. 20. Participant has major organ damage, including: 1. Symptomatic splenomegaly 2. Liver disease with alanine aminotransferase (ALT)/aspartate aminotransferase (AST) > 3X the upper limit of normal (ULN) for age 3. Heart disease, heart failure as classified by the New York Heart Association (NYHA) classification 3 or higher, or significant arrhythmia requiring treatment, or recent myocardial infarction within 6 months of enrollment 4. Lung disease, including pulmonary fibrosis or pulmonary hypertension which are clinically significant 5. Renal insufficiency defined as:
- A serum creatinine based on age/gender based on threshold derived from Schwartz formula for estimating GFR utilizing child length and stature data published by the Centers for Disease Control 21. Participant has proteinuria ≥ Grade 3 according to NCI CTCAE version 5.0 (which is equivalent to a urine protein/creatinine ratio > 215 mg/mmol of creatinine), or a urine albumin/creatinine ratio > 129 mg/mmol of creatinine. 22. Participant use of chronic systemic glucocorticoids ≤ 12 weeks prior to enrollment (physiologic replacement therapy for adrenal insufficiency is allowed). Single day glucocorticoid treatment (eg, for prevention or treatment of transfusion reactions) is allowed. 23. Participant has major surgery ≤ 12 weeks prior to enrollment (participants must have completely recovered from any previous surgery prior to enrollment). 24. Participant has history of severe allergic or anaphylactic reactions or hypersensitivity to recombinant proteins or excipients in the IP (refer to the IB). 25. Participant use of cytotoxic agents, immunosuppressants ≤ 28 days prior to enrollment (ie, antithymocite globulin (ATG) or cyclosporine). 26. Participant has history of malignancy with the exception of: 1. Curatively resected nonmelanoma skin cancer. 2. Curatively treated cervical carcinoma in situ. 3. Other solid tumor with no known active disease in the opinion of the Investigator. 27. Participant who has EMH complications or requires treatment to control the growth of EMH masse(s) during the screening period.