Merck, known as MSD outside the U.S. and Canada, has entered a deal through a subsidiary to acquire Acceleron Pharma $11.5 billion.   Acceleron is focused on harnessing the power of the transforming growth factor (TGF)-beta superfamily of proteins that is known to play a central role in the regulation of cell growth, differentiation and repair. Acceleron’s lead therapeutic candidate, sotatercept, has a novel mechanism of action with the potential to improve short-term and/or long-term clinical o...