Acceleron Pharma Inc. is a United States-based clinical stage biopharmaceutical company. The Company focuses on discovering and developing therapies to treat a range of diseases. Its therapeutic candidate, luspatercept, is being evaluated in Phase III studies for the treatment of the hematologic diseases myelodysplastic syndromes (MDS) and beta-thalassemia. Its Sotatercept is an investigational protein therapeutic that manages red blood cell levels by targeting molecules in the transforming growth factor beta (TGF-β) superfamily, which is being evaluated in Phase IIa studies. Its Dalantercept is an investigational protein therapeutic that inhibits angiogenesis by preventing bone morphogenetic proteins 9 (BMP) and BMP10, proteins in the TGF-β superfamily, which is being evaluated in Phase II studies. Its ACE-083 is an investigational protein therapeutic that helps to manage muscle mass and strength in specific muscles and muscle groups, which is being evaluated in Phase I studies.