Genmab Acquires Merus for $8 Billion: The First Organoid-Discovered Clinical Asset Drives the Largest European Oncology Deal of 2025

Abstract

COPENHAGEN & UTRECHT – September 29, 2025 – In  the largest European oncology acquisition of 2025,  Genmab A/S (Nasdaq: GMAB) has agreed to  acquire Merus N.V. (Nasdaq: MRUS) for  approximately $8 billion in cash, or $97.00 per  share. The transaction instantly delivers full  ownership of petosemtamab (MCLA-158), a  first-in-class EGFR × LGR5 bispecific antibody that  represents a historic milestone: it is the first  therapeutic candidate discovered, prioritized, and  advanced into Phase III clinical trials exclusively  through patient-derived organoid (PDO) screening.  With two FDA Breakthrough Therapy Designations  already secured and Phase III trials actively  enrolling globally, petosemtamab has rapidly  emerged as one of the most promising  investigational therapies in head-and-neck  squamous cell carcinoma (HNSCC) and is projected  to achieve multibillion-dollar peak sales.  Breakthrough Therapy Designation is granted to  expedite the development and review of drugs that  show substantial improvement over existing  therapies for serious conditions.