A Phase 2a Study To Evaluate The Pharmacokinetics, Safety, Efficacy, Tolerability, And Pharmacodynamics of Sotatercept (ACE-011) for the Correction of Anemia in Subjects With End-stage Renal Disease on Hemodialysis.

Inclusion Criteria: * Males or females ≥18 years of age. * Subjects on hemodialysis for at least 12 weeks before screening * Subjects on a stable dose of Erythrocyte Stimulating Agents product to maintain Hemoglobin (Hb) for at least 6 weeks prior to screening. * 3 consecutive pre-dialysis Hb concentrations with a mean ≥10 to ≤ 12 g/dL (≥100 to ≤120 g/L) at screening and one pre-dialysis Hb concentration ≥8 to \< 10 g/dL (≥ 80 to \< 100 g/L) before randomization. * Adequate iron status defined as serum transferrin saturation ≥ 20% before randomization. Exclusion Criteria: * Non renal causes of anemia. * Subjects on peritoneal dialysis. * Systemic hematological disease * High sensitivity C-reactive protein \>50mg/L at screening. * Alanine transaminase (ALT) or aspartate transaminase (AST) laboratory values \> 2 times the upper limit of normal (ULN) at screening. * Uncontrolled diabetes mellitus (HbA1c \> 9) at screening. * Uncontrolled hypertension. * Red Blood Count (RBC) transfusions within 8 weeks prior to screening. * Active serious infection or history of recurrent serious infection likely to recur during the study * History of severe allergic or anaphylactic reactions or hypersensitivity to recombinant proteins or excipients in the investigational product or to the iron products needed to normalize iron levels for subjects. * Subjects that received treatment with another investigational drug or device within 28 days prior to Day 1 * Pregnant or lactating females.