Acceleron Recognized by The Wall Street Journal as One of the Top 50 Venture-Backed Companies in the United States

Acceleron Pharma, Inc.

Acceleron Recognized by The Wall Street Journal as One of the Top 50 Venture-Backed Companies in the United States

March 10, 2010

CAMBRIDGE, Mass. – March 10, 2010 - Acceleron Pharma, Inc., a biopharmaceutical company developing novel therapeutics that modulate the growth of cells and tissues including red blood cells, bone, muscle, fat and the vasculature, today announced that it was recognized by VentureSource, a unit of Wall Street Journal owner News Corp. as one of the top 50 venture capital-backed companies in the United States. The rankings were based on criteria including the track records of the company’s founders, management, and board members; the amount of capital raised over the last three years; and the increase in the company’s valuation during the past 12 months. There are approximately 10,000 privately held, venture-backed companies in the U.S.

“We are proud to be recognized by The Wall Street Journal as one of the top 50 venture-backed companies in the country,” said John Knopf, Ph.D., Chief Executive Officer of Acceleron. “We have worked extremely hard to build a company with extraordinary clinical and commercial potential, and we are honored to be recognized by such a respected source. I would like to thank all of our employees, investors and corporate partners for their contributions to enable this achievement.”

About Acceleron

Acceleron is a privately held biopharmaceutical company committed to discover, develop, manufacture and commercialize novel biotherapeutics that modulate the growth of red blood cells, bone, muscle, fat and the vasculature to treat musculoskeletal, metabolic and cancer-related diseases. Acceleron’s scientific approach takes advantage of its unique insight into the regenerative powers of the TGF-ß superfamily of proteins. ACE-011 is currently being studied in a Phase 2 clinical trial in breast cancer patients. ACE-031 is currently being studied in a Phase 1 clinical trial in healthy volunteers and ACE-041 is being studied in a Phase 1 clinical trial in patients with advanced cancer. In addition, the company is developing several other new product candidates that increase muscle mass, control angiogenesis, inhibit fat accumulation and increase bone mass and strength. Acceleron utilizes proven biotherapeutic technologies and capitalizes on the company’s internal GMP manufacturing capability to rapidly and efficiently advance its therapeutic programs. The investors in Acceleron include Advanced Technology Ventures, Alkermes, Bessemer Ventures, Celgene, Flagship Ventures, MPM BioEquities, OrbiMed Advisors, Polaris Ventures, QVT Financial, Sutter Hill Ventures and Venrock. For more information, visit www.acceleronpharma.com.

CONTACT:

Acceleron Pharma:
Steven Ertel, 617-649-9234
Vice President, Corporate Development

Paul Kidwell (Media)
Suda Communications LLC, 617-296-3854