Acceleron Pharma Inc. Information Request Form

Levi & Korsinsky, LLP has commenced an investigation into the fairness of the merger of Acceleron Pharma Inc. (“NASDAQ: XLRN”) (“Acceleron” or “Company”) with Merck & Co., Inc. (NYSE: MRK) Under the terms of the merger, Acceleron stockholders will receive $180 in cash for each share of Acceleron common stock owned.

The Acceleron merger investigation concerns whether the Board of Acceleron has harmed stockholders by agreeing to enter into this transaction and whether all material facts have been properly disclosed to stockholders.