Acceleron Pharma, Inc. is an American clinical stage biopharmaceutical company based in Cambridge, Massachusetts with a broad focus on developing medicines that regulate the transforming growth factor beta (TGF-β) superfamily of proteins, which play fundamental roles in the growth and repair of cells and tissues such as red blood cells, muscle, bone, and blood vessels.

[10][11][12] The founders were scientists Jasbir Seehra, Tom Maniatis, Mark Ptashne, Wylie Vale, and scientific advisor Joan Massague, and business people and investors John Knopf and Christoph Westphal of Polaris Venture Partners, who served as founding CEO.

[15] It started its first clinical trial in June 2006; the product was ACE-011 (which eventually was named "sotatercept"),[7] a protein therapeutic that was an activin type 2 receptor antagonist intended to treat bone loss.

[19][20] In a separate deal done at the same time, Celgene acquired an option to license three products in Acceleron's pipeline directed to cancer and cancer-related bone loss.

[23] Acceleron experienced a drop in its share prices in 2019, after announcing that it will discontinue the development of an experimental drug meant to treat the rare genetic disease called facioscapulohumeral muscular dystrophy.