Pfizer Acquires Metsera

Pfizer Acquires Arena Pharmaceuticals

December 13, 2021

Pharmaceuticals

Pfizer Inc. agreed to acquire clinical-stage Arena Pharmaceuticals for $100 per share in an all-cash transaction valued at approximately $6.7 billion, creating a wholly owned subsidiary. The acquisition brings Arena's development-stage portfolio — including etrasimod and cardiovascular assets — into Pfizer's Inflammation & Immunology pipeline to accelerate clinical development and expand therapeutic capabilities.

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.

Genmab A/S Acquires Merus N.V. via Tender Offer

December 12, 2025

Biotechnology

Genmab A/S, through its wholly owned purchaser Genmab Holding II B.V., completed a tender offer to acquire outstanding common shares of Merus N.V. for $97.00 per share and commenced a subsequent offering period. The acquisition adds Merus' lead late‑stage oncology asset petosemtamab to Genmab's portfolio, expanding its antibody therapeutics pipeline and expected to be accretive to EBITDA by 2029.

MorphoSys Acquires Constellation Pharmaceuticals for $1.7B

June 2, 2021

Biotechnology

MorphoSys AG has agreed to acquire Constellation Pharmaceuticals for $34.00 per share in cash, valuing the transaction at approximately $1.7 billion. The deal strengthens MorphoSys' hematology-oncology pipeline by adding Constellation's mid- to late-stage candidates (pelabresib/CPI-0610 and CPI-0209) and is supported by a strategic funding partnership with Royalty Pharma that provides significant upfront and milestone funding.

Merck Acquires Prometheus Biosciences for $10.8 Billion

June 16, 2023

Biotechnology

Merck has agreed to acquire clinical-stage biotechnology company Prometheus Biosciences for $200.00 per share in cash, representing an approximate total equity value of $10.8 billion. The acquisition strengthens Merck's immunology pipeline by adding Prometheus' precision-medicine platform and lead candidate PRA023 (MK-7240) for inflammatory bowel disease and other immune-mediated conditions.

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.