Acceleron Pharma

What Acceleron Pharma does

Acceleron Pharma was a clinical-stage biopharmaceutical company founded in 2004 and headquartered in Cambridge, Massachusetts, that developed novel biotherapeutics targeting pulmonary arterial hypertension (PAH) and fibrotic diseases. The company's lead asset was Winrevair (sotatercept), a first-in-class therapeutic targeting alveolar epithelial type 2 cells to repair and reverse fibrotic damage in lung tissue. In Phase 3 ZENITH trials, Winrevair demonstrated a 76% reduction in major morbidity and mortality risk in high-risk PAH patients, establishing a differentiated mechanism of action in the pulmonary therapeutic space. The company was acquired by Merck & Co. for $11.5 billion in 2021 as part of Merck's strategy to offset the impending exclusivity loss of its flagship drug Keytruda and expand its cardiometabolic and respiratory portfolio.

Following the acquisition, Acceleron no longer operates as a standalone entity, and Winrevair is commercialized through Merck's established global pharmaceutical distribution network spanning specialty pharmacies, hospital channels, and retail pharmacy networks. Winrevair generated $525 million in Q1 2025 sales with 12% sequential quarterly growth and is projected to reach $6.1 billion in annual sales by 2030, positioning it as a key growth driver for Merck's post-Keytruda portfolio. The company had raised approximately $1.3 billion across multiple funding rounds from 2004 through 2020, with strategic backing from Celgene and leading biotech-focused venture capital firms including Flagship Pioneering, OrbiMed, Polaris Partners, and Bessemer Venture Partners.

The business model centered on developing biotherapeutic candidates through clinical trials to regulatory approval, then commercializing either independently or through strategic partnerships. Acceleron's patient segment was narrowly defined as WHO Group 1 pulmonary arterial hypertension patients requiring therapeutic intervention, a specialty population with high unmet medical need. Post-acquisition, all revenue and commercial activity flows through Merck, and former Acceleron executives have subsequently founded adjacent ventures including Oorja Bio, backed by Westlake BioPartners with $30 million in Series A financing, to extend the fibrotic disease research platform into new independent entities.

Name

Acceleron Pharma

Website

https://acceleronpharma.com

Company type

Private

Founded year

2004

Operating status

Acquired

Headcount range

101–250 employees

Short description

Acceleron Pharma was a clinical-stage biopharmaceutical company that developed Winrevair (sotatercept), a first-in-class therapy for pulmonary arterial hypertension. Acquired by Merck for $11.5 billion in 2021, it no longer operates as a standalone entity.

Ownership category

akta.pro rank

Product category

Pulmonary Hypertension Therapeutics

NAICS

Biological Product (except Diagnostic) Manufacturing (325414), Pharmaceutical Preparation Manufacturing (325412)

SIC

Pharmaceutical Preparations (2834), Biological Products, (No Disgnostic Substances) (2836)

akta.pro primary industry

Pulmonary Hypertension & Rare Pulmonary Disease Therapies (HLAIAIAG)

akta.pro secondary industries

Pulmonology & Allergy Specialty Pharmaceuticals (HLAIACAF), Cardiometabolic Pharmaceuticals (Cardiovascular/Diabetes/Obesity) (HLAIAAAE)

Keywords

• Pulmonary hypertension therapeutics
• Biopharmaceutical drug development
• Fibrotic disease therapies
• Novel biotherapeutics development
• Rare disease treatments

Headquarters

HQ city

Cambridge

HQ country

United States

HQ region

North America

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Personnel, Technology or R&D, Operations, Marketing or Sales, Supply Chain

Distribution channels1 record

Core offering

Acceleron Pharma is a biopharmaceutical company that develops and commercializes novel biotherapeutics targeting pulmonary arterial hypertension (PAH) and serious rare diseases. The company's lead product, Winrevair (sotatercept), is a first-in-class activin signaling inhibitor approved for the treatment of adults with PAH.

Product overview

Acceleron Pharma was a clinical-stage biopharmaceutical company focused on developing therapies for pulmonary and hematologic diseases. The company's lead product was Winrevair (sotatercept), a therapy for pulmonary arterial hypertension. Acceleron Pharma was acquired by Merck in 2021 for $11.5 billion. As an independent entity, Acceleron operated with a single-product focus prior to acquisition, with its portfolio and pipeline now integrated into Merck's cardiometabolic and respiratory diseases research area.

Differentiator

Problem solved

Functional benefit

Products and services

• Winrevair (sotatercept) Winrevair is a fusion protein therapeutic indicated for the treatment of adult patients with pulmonary arterial hypertension (PAH). It is administered as a subcutaneous injection and is used in combination with standard PAH background therapy. The product targets the activin signaling pathway, addressing an underlying cause of PAH rather than just vasodilation.

Quantifiable outcome

• 76% reduction in major morbidity and mortality risk in high-risk PAH patients
• +2 more outcomes

Segments1 record

Ideal customer profiles1 record

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature1 record

Scale indicators3 records

Recent moves5 records

Expansion highlights4 records

Broad incumbents

• Pfizer: Pfizer markets Revatio (sildenafil citrate) for PAH and has a broad cardiovascular/pulmonary franchise. As a broad incumbent, it competes in earlier-line PAH treatment where Winrevair may be added on top.
• Roche: Roche operates in the broader respiratory and pulmonary hypertension space and has historically participated in PAH therapeutics (e.g., through Actelion-adjacent assets). As a global biopharmaceutical incumbent, it represents indirect competitive pressure.
• Bayer AG: Bayer markets Adempas (riociguat), the only approved sGC stimulator for PAH and CTEPH. As a broad pharmaceutical incumbent with prior Bayer leadership at Acceleron, it represents an established PAH therapy competitor.
• Bristol Myers Squibb: BMS operates in cardiopulmonary disease and has historical commercial capability in cardiovascular therapeutics. As a broad incumbent, it represents potential competition for franchise-level specialty pharma positioning in PAH.
• Janssen Pharmaceuticals (Johnson & Johnson): Janssen markets Opsumit (macitentan), Tracleer (bosentan), and Uptravi (selexipag) — the leading ERA and prostacyclin therapies for PAH. As a large incumbent, Janssen competes across multiple PAH lines of therapy where Winrevair is positioned.

Direct peers

• Liquidia Technologies: Liquidia is advancing YUTREPIA, an inhaled dry-powder treprostinil for PAH and PH-ILD. It is a direct functional competitor to Winrevair in PAH with improved delivery technology and partial overlap in indication.
• United Therapeutics: United Therapeutics is the leading specialty PAH company with Tyvaso (inhaled treprostinil), Remodulin, and Orenitram. It is the most direct competitor to Winrevair in the PAH space, serving the same patient population with prostacyclin-class therapies.

Emerging players

• Gossamer Bio: Gossamer Bio is developing seralutinib (inhaled tyrosine kinase inhibitor) for PAH. As an emerging PAH-focused biotech with a novel inhaled mechanism, it represents partial overlap with the Winrevair franchise.
• Aerovate Therapeutics: Aerovate is developing inhaled imatinib for PAH, an emerging targeted therapy addressing vascular remodeling. Its mechanism and indication directly intersect with Winrevair's therapeutic space.
• Pulnovo Medical: Pulnovo Medical is a China-based emerging company developing pulmonary hypertension therapies, including pulsed electric field ablation for PAH. It represents an emerging regional/international competitor in the broader PAH treatment space.

Market position

Strengths4 records

Weaknesses5 records

Competitive moat4 records

Key risks6 records

Key highlights6 records

Customer concentration

• Xx.com/acceleronpharma
• Facebookfacebook.com/649175928516083
• LinkedInlinkedin.com/company/acceleron-pharma

Revenue estimate

Valuation estimate

Number of profiles

Funding overview

Funding rounds15 records

Investors11 records

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Acceleron Pharma