Genmab has signed an agreement to buy all shares of clinical-stage biotechnology company Merus at $97 per share, in an all-cash transaction valued at $8bn, boosting its oncology pipeline.
The acquisition, which has received unanimous support from both companies' boards of directors, is expected to advance Genmab's transition to a fully owned business model.
A subsidiary of Genmab will initiate a tender offer to acquire 100% of the common shares of Merus, with the deal projected to close early in the first quarter of 2026.
The key asset addition for Genmab is Merus' EGFRxLGR5 bispecific antibody, petosemtamab, currently in Phase III development.
The US Food and Drug Administration (FDA) has granted two breakthrough therapy designations for the therapy for the treatment of head and neck cancer.
Merus is conducting two Phase III studies of petosemtamab for first and second/third-line head and neck cancer, with interim readout of one or both studies expected in 2026.
Genmab aims to launch petosemtamab in 2027, contingent on clinical outcomes and regulatory clearances. The company also plans to expand the therapy’s development into earlier treatment lines.
The acquisition price reflects a 41% premium over the closing stock price of Merus on 26 September 2025, and 44% over the 30-day volume-weighted average price of $67.42.
The transaction is not contingent on financing, as Genmab intends to fund the purchase through existing cash and $5.5bn in non-convertible debt, with a commitment from Morgan Stanley Senior Funding.
Advising Genmab on the transaction are PJT Partners and Morgan Stanley & Co International, with legal counsel from A&O Shearman and Kromann Reumert.
Merus is advised by Jefferies, with legal counsel from Latham & Watkins and NautaDutilh.
Genmab CEO and president Jan van de Winkel stated: “The proposed acquisition of Merus clearly aligns with our long-term strategy. It has the potential to significantly accelerate our evolution into a global biotechnology leader by providing durable growth for the company well into the next decade.
“Petosemtamab has the potential to be a transformational therapy for patients living with head and neck cancer.”
In March 2025, Genmab secured approval in Japan for Tivdak, a treatment for advanced or recurrent cervical cancer that progressed on or following chemotherapy.
