Pfizer Acquires Arena Pharmaceuticals

Pfizer Acquires Seagen for $43 Billion

December 14, 2023

Biotechnology

Pfizer completed the acquisition of Seagen, acquiring all outstanding Seagen common stock for $229 per share in cash in a transaction valued at approximately $43 billion. The deal adds Seagen's ADC technology, four in-line oncology medicines and a large early-stage pipeline to Pfizer's oncology portfolio, expanding Pfizer's capabilities and doubling its oncology pipeline.

Pfizer Acquires Metsera

November 13, 2025

Biotechnology

Pfizer Inc. completed the acquisition of clinical-stage biopharmaceutical company Metsera, Inc. for $65.60 per share (approximately $7.0 billion enterprise value) plus contingent value rights of up to $20.65 per share. The deal brings Metsera's obesity and cardiometabolic therapeutic candidates into Pfizer's pipeline and makes Metsera a wholly owned subsidiary headquartered in New York.

Merck Acquires Acceleron Pharma for $11.5 Billion

September 30, 2021

Biotechnology

Merck has entered into a definitive agreement to acquire Acceleron Pharma Inc. for $180 per share in cash, representing an approximate total equity value of $11.5 billion. The acquisition brings Acceleron's late-stage sotatercept program (for pulmonary arterial hypertension) and its REBLOZYL portfolio into Merck's cardiovascular pipeline, subject to tender offer completion and customary regulatory approvals.

Sun Pharmaceutical Industries Acquires Concert Pharmaceuticals

January 19, 2023

Biotechnology

Sun Pharmaceutical Industries Limited agreed to acquire all outstanding shares of Concert Pharmaceuticals, Inc. via a tender offer for $8.00 per share (approximately $576 million equity value) plus a non-tradeable contingent value right (CVR) of up to $3.50 per share tied to deuruxolitinib sales milestones. The deal adds Concert's late-stage JAK1/2 inhibitor deuruxolitinib for Alopecia Areata to Sun Pharma's global dermatology franchise; Sun Pharma intends to pursue an NDA submission in H1 2023 and expected close was Q1 2023, subject to tender conditions and regulatory approvals.

Amgen Completes Acquisition of Horizon Therapeutics plc

October 6, 2023

Biotechnology

Amgen completed the acquisition of Horizon Therapeutics plc for $116.50 per share in cash, valuing the transaction at approximately $27.8 billion. The deal expands Amgen's inflammation and rare-disease portfolio by adding Horizon's medicines (including TEPEZZA, KRYSTEXXA and UPLIZNA) and strengthens Amgen's biologics R&D, manufacturing and global commercial capabilities.

Merck Acquires Pandion Therapeutics

February 25, 2021

Biotechnology

Merck will acquire Pandion Therapeutics for $60 per share in cash, representing an approximate total equity value of $1.85 billion, via a tender offer and subsequent merger. Pandion is a clinical-stage biotechnology company focused on precision immune modulators (TALON platform) with lead candidate PT101 targeting regulatory T cells for autoimmune diseases; the transaction is expected to close in the first half of 2021 subject to customary conditions.