Acceleron Named a "Most Honored" Company in Institutional Investor 2020 "All-America Executive Team" Rankings

Acceleron Pharma Inc. (Nasdaq:XLRN), a leading biopharmaceutical company in the discovery and development of TGF-beta superfamily therapeutics to treat serious and rare diseases, announced today that it has been included in the recently released Institutional Investor 2020 "All-America Executive Team" rankings as one of the country's "Most Honored" companies.

Institutional Investor is widely considered the leading publication for institutional investors, including money managers and pension fund managers. Each year, the publication releases its All-America Executive Team rankings, which reflect extensive polling of investment professionals to name the best CEOs, CFOs, and investor relations (IR) teams. The 2020 rankings are based on the opinions of nearly 1,700 portfolio managers, buy-side analysts, and sell-side analysts. This year, nearly 1,500 companies across a wide range of sectors received votes in the Institutional Investor polling process, of which only 147 companies were deemed "Most Honored."

"We're pleased to be named a ?Most Honored' company in the latest Institutional Investor rankings, alongside some of this country's largest, best-known enterprises," said Habib Dable, President and Chief Executive Officer of Acceleron. "This recognition is a reflection of our concerted effort as a team to communicate our growth strategy in as transparent, responsive, and accessible fashion as possible to the investor and analyst communities."

Companies earning the "Most Honored" designation had to receive two or more top-three appearances in the categories of Best CEO, CFO, IR Professional, and IR Program. Acceleron was also recognized for its overall IR program as well as for its performance in metrics of environmental and social responsibility.

About Acceleron

Acceleron is a biopharmaceutical company dedicated to the discovery, development, and commercialization of therapeutics to treat serious and rare diseases. The Company's leadership in the understanding of TGF-beta superfamily biology and protein engineering generates innovative compounds that engage the body's ability to regulate cellular growth and repair.

Acceleron focuses its research and development efforts in hematologic, neuromuscular, and pulmonary diseases. In hematology, the Company and its global collaboration partner, Bristol-Myers Squibb, are co-promoting newly approved REBLOZYL^® (luspatercept-aamt), the first and only approved erythroid maturation agent, in the United States and are developing luspatercept for the treatment of chronic anemia in myelodysplastic syndromes and myelofibrosis. Acceleron is also advancing its neuromuscular program with ACE-083, a locally-acting Myostatin+ agent in Phase 2 development in Charcot-Marie-Tooth disease and is conducting a Phase 2 pulmonary program with sotatercept in pulmonary arterial hypertension.

For more information, please visit www.acceleronpharma.com. Follow Acceleron on Social Media: @AcceleronPharma and LinkedIn.