Acceleron Pharma Appoints Robert Steininger as Senior Vice President, Manufacturing

Acceleron Pharma, Inc.

Acceleron Pharma Appoints Robert Steininger as Senior Vice President, Manufacturing

March 29, 2007

CAMBRIDGE, Mass.--(BUSINESS WIRE)--Mar 29, 2007 - Acceleron Pharma, Inc., a biopharmaceutical company developing therapeutics for the treatment of musculoskeletal, metabolic and cancer-related diseases, today announced the appointment of Robert Steininger as Senior Vice President, Manufacturing.

"Acceleron is rapidly advancing and expanding our product pipeline of novel protein therapeutics to treat musculoskeletal, metabolic and cancer-related diseases. Since our inception, we have manufactured our preclinical and clinical material in our GMP manufacturing facility and are committed to continuing this value-creating capability. We are pleased to have Bob join Acceleron and our management team as he brings substantial experience and expertise that will help us continue the tremendous progress we're making across all of our development programs," said John Knopf, Ph.D., Interim President of Acceleron.

"I'm excited to join Acceleron and lead the growth of the manufacturing organization as this function will be critical to the success of the company," said Mr. Steininger. "Our lead program, ACE-011, will be entering phase 2 clinical trials later this year and we expect our second and third programs to enter phase 1 trials this year as well. Acceleron's commitment to internally produce protein therapeutics in its own facility, a rare capability among most biotechnology companies, ensures that we can rapidly, efficiently and cost-effectively advance our pipeline products. We will continue to build and invest in this area to support the development of our rich pipeline of novel biotherapeutics."

Mr. Steininger was previously the Vice President of Process Sciences at Millennium Pharmaceuticals. In this capacity, he was responsible for managing the processes for the bulk production of both large and small molecule clinical candidates. Mr. Steininger also served as a VP within the Millennium Product and Portfolio Management organization. Prior to joining Millennium, he held multiple roles at Genetics Institute (now Wyeth Pharmaceuticals) from 1984 to 2000, including Director of Clinical Production, Director of Process Technology, Director of Regulatory Affairs, and Senior Director of Research, Genomics. Mr. Steininger is a member of the advisory board for the Massachusetts chapter of ISPE, an Advisory Board member of the Chemical Engineering Department of the University of Massachusetts, Amherst, and on the Biotechnology Advisory Board for the RISTA program at the Cambridge High School. He has been involved in setting up Biotechnology outreach programs with local grade schools and high schools while at Wyeth and Millennium. Mr. Steininger received a S.B. in chemistry from Massachusetts Institute of Technology and an M.S. in Chemical Engineering from the University of California, Berkeley.

About Acceleron Pharma

Acceleron is a privately held biopharmaceutical company committed to discover, develop, manufacture and commercialize novel biotherapeutics that modulate the growth of bone, muscle, fat and the vasculature to treat musculoskeletal, metabolic and cancer-related diseases. Acceleron's scientific approach takes advantage of its unique insight on the regenerative powers of two protein families: the Growth and Differentiation Factor (GDF) and Bone Morphogenetic Protein (BMP) families. The company's lead program is an anabolic bone agent being developed to reverse bone loss in diseases such as osteoporosis and cancer. Additionally, the company is advancing several preclinical programs that increase muscle mass, control angiogenesis and inhibit fat accumulation. 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 are Advanced Technology Ventures, Flagship Ventures, OrbiMed Advisors, Polaris Ventures, Sutter Hill Ventures and Venrock Associates.

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Acceleron Pharma
Steven Ertel, 617-576-2220 x234
Vice President, Business Development

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