Acceleron Pharma was a prominent clinical-stage biopharmaceutical enterprise focused on discovering, developing, and commercializing novel protein therapeutics targeted at treating serious and rare diseases, particularly focusing on pulmonary and hematological disorders. Operating out of its headquarters in Cambridge, Massachusetts, the company leveraged its deep scientific expertise in the transforming growth factor beta superfamily to advance innovative drug candidates. Its leading developmental breakthrough was sotatercept, a first-in-class therapeutic candidate designed for pulmonary arterial hypertension. Additionally, the firm co-developed and commercialized Reblozyl alongside major pharmaceutical partners to treat anemia in rare blood conditions before being acquired by Merck.