Acceleron Pharma

Acceleron Pharma, Inc.

Company type	Subsidiary
Industry	Biopharmaceutical
Founded	June 2003 (2003-06)
Founder	Jasbir Seehra, Tom Maniatis, Mark Ptashne, Wylie Vale
Headquarters	Cambridge, Massachusetts , United States
Area served	Worldwide
Key people	Habib Dable (CEO)
Products	Luspatercept, Sotatercept, Dalantercept, ACE-083
Parent	Merck & Co.

Acceleron Pharma, Inc. is a clinical-stage biopharmaceutical firm based in Cambridge, Massachusetts, United States. The company specializes in developing therapies that target the transforming growth factor beta (TGF-β) superfamily, a group of proteins that control cellular and tissue growth and repair processes, including those involving red blood cells, muscle tissue, bone, and blood vessels.

Pipeline

The drug development pipeline at Acceleron consists of four candidates currently undergoing clinical trials and one in the preclinical phase:

• Luspatercept (ACE-536), aimed at treating anemia
• Sotatercept (ACE-011), developed for pulmonary arterial hypertension
• Dalantercept (ACE-041), targeted at kidney cancer
• ACE-083, intended for muscular disorder therapies

History

Founded in June 2003 as a Delaware corporation initially named Phoenix Pharma, Acceleron Pharma was established in Cambridge, Massachusetts. The founding team included scientists Jasbir Seehra, Tom Maniatis, Mark Ptashne, and Wylie Vale, with advisory input from Joan Massague. Investors John Knopf and Christoph Westphal from Polaris Venture Partners were also instrumental in the company's inception, with Westphal taking on the role of its first CEO. Acceleron's mission was to create therapeutics based on discoveries related to growth factors and transforming growth factors for metabolic conditions such as obesity, diabetes, osteoporosis, and muscle degeneration disorders.

Initial capital was raised through a $250,000 seed investment from Polaris Venture Partners, followed by a $25 million Series A round that funded the establishment of their initial laboratory facility in December 2003. Glenn Batchelder assumed the roles of president and CEO in June 2004.

Acceleron's inaugural clinical trial began in June 2006 for ACE-011 (later renamed "sotatercept"), a protein-based therapeutic designed as an antagonist to the activin type 2 receptor, intended to address bone loss conditions. ACE-011 is a chimeric molecule combining activin receptor binding domains with antibody fragments to block activin signaling.

In 2007, John Knopf took over as CEO and became recognized for using imagery of a muscular Belgian Blue cattle breed to symbolize the promise of Acceleron's muscle-enhancing treatments. The following year, Acceleron formed a strategic alliance with Celgene, which included an upfront payment of $50 million, acquisition of $5 million in stock, and potential milestone payments totaling up to $510 million to jointly develop and commercialize ACE-011. Celgene also obtained licensing rights for three oncology-focused pipeline candidates.

This collaboration expanded in 2011 to incorporate ACE-536 (later known as luspatercept), targeting anemia treatment. Celgene contributed an additional $25 million upfront with potential milestone payments amounting to $217 million plus royalties exceeding 10%.

Acceleron went public in September 2013 while advancing three protein therapeutics through development supported by 12 Phase 2 clinical studies: sotatercept and luspatercept for anemia associated with thalassemia and myelodysplastic syndromes (MDS), alongside dalantercept (ACE-041), an angiogenesis inhibitor aimed at cancer therapy.

After Knopf’s retirement in September 2016, Habib Dable was appointed CEO. At that time, luspatercept had progressed into Phase III trials for MDS and beta-thalassemia.

In 2019, Acceleron’s stock value fell following the termination of an experimental treatment for facioscapulohumeral muscular dystrophy amid shareholder concerns regarding development expenses.

In September 2021, Merck & Co. announced its intent to acquire Acceleron for $11.5 billion, thereby gaining ownership of sotatercept and luspatercept-aamt. The transaction was finalized on November 19, 2021, making Acceleron a subsidiary of Merck.

By October 2022, Merck disclosed favorable Phase III outcomes for sotatercept, underscoring the strategic value of its investment in Acceleron’s cardiovascular drug portfolio.