Boston-based company Acceleron Pharma specializes in developing protein therapeutics for cancer and rare diseases. The company's products in development include sotatercept and ACE-536, both in Phase II clinical trials. They aim to treat anemia and associated complications in patients with ß-thalassemia and myelodysplastic syndromes, as well as red blood cell disorders. Acceleron's dalantercept is also in Phase II clinical trials, with the goal of inhibiting blood vessel formation in tumors through the use of vascular endothelial growth factor pathway inhibitors.