Pharma BD Deal Intelligence

Merck & Co. Inc. / Acceleron Pharma Inc.

2021 · Acquisition/Merger · $11.5B · Complete

The Street Said

Strongly positive — critic reaction at announcement

History Says

Worked — the deal delivered on its rationale

CALLED IT — OFF BY 12

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Top 25 largest deals of the 2020s

Ranks computed across 828 graded deals (Critic + Outcome Score both present).

The coverage arc

Sep 30, 2021 BioPharma Dive Neutral

Acceleron provides biggest biopharma deal this year, with $11.5B sale to Merck.

Oct 27, 2025 Merck Press Release - ZENITH Label Expansion Bullish

FDA approved updated WINREVAIR indication (Oct 27, 2025) adding reduced risk of clinical worsening (hospitalization for PAH, lung transplantation, death);…

Apr 30, 2026 Merck Press Release - Q1 2026 Results Bullish

WINREVAIR Q1 2026 sales $525M (88% growth; 87% ex-FX), driven by continued U.S. uptake and early launch in Japan and Europe.

Source summaries from our enrichment pipeline; follow links for originals.

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Merck acquired Acceleron Pharma for approximately $11.5 billion ($180 per share in cash), gaining sotatercept, an investigational first-in-class activin signaling inhibitor in Phase III for pulmonary arterial hypertension, and REBLOZYL (luspatercept) for anemia in rare blood disorders.

Key facts

Announced Sep 30, 2021
Closed Nov 22, 2021
Deal value $11.5B
Deal type Acquisition/Merger
Therapeutic area Cardiovascular, Hematology, Rare Disease, Respiratory
Indications Pulmonary Arterial Hypertension (PAH), Anemia in Myelodysplastic Syndromes, Beta-Thalassemia
Key assets sotatercept (PAH), REBLOZYL (luspatercept), TGF-beta superfamily signaling platform
Mechanism Activin receptor type IIA-Fc fusion protein (TGF-beta superfamily trap), Erythroid maturation agent

Related deals — scored

Deal	Year	Value	Outcome
Merck & Co. Inc. / Acceleron Pharma Inc. (this deal)	2021	$11.5B	90
Merck & Co. Inc. / Peloton Therapeutics Inc.	2019	$2.2B	88
Merck & Co. Inc. / AstraZeneca PLC	2017	$8.5B	87
Merck & Co. Inc. / Moderna, Inc.	2022	$250M	86
Merck & Co. Inc. / Moderna, Inc.	2016	$250M	84
Merck & Co. Inc. / Eisai Co., Ltd.	2018	$5.8B	83
Merck & Co. Inc. / Prometheus Biosciences Inc.	2023	$10.8B	77

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