 NEW YORK--BUSINESS WIRE--Halper Sadeh LLP, a global investor rights law firm, is investigating whether the sale of Acceleron Pharma Inc. NASDAQ: XLRN to Merck Co., Inc. for 180.00 per share in cash is fair to Acceleron shareholders. Halper Sadeh encourages Acceleron shareholders to click here to learn more about their legal rights and options or contact Daniel Sadeh or Zachary Halper at 212 763-0060 or or The investigation concerns whe 