Genmab agrees $8bn Merus deal

December 2025 | DEALFRONT | MERGERS & ACQUISITIONS

Financier Worldwide Magazine

December 2025 Issue

Danish biotechnology company Genmab has agreed to acquire Dutch clinical-stage oncology firm Merus in an all-cash transaction valued at $8bn.

Under the terms of the agreement, Genmab will pay $97 per share to acquire Merus, representing a 41 percent premium over the company’s closing price on Friday 26 September, the last trading day before the deal was announced.

The acquisition is expected to close early in the first quarter of 2026 and has been unanimously approved by the boards of directors of both companies.

Genmab will fund the transaction through a combination of existing cash reserves and approximately $5.5bn in non-convertible debt financing. The company has secured a funding commitment from Morgan Stanley Senior Funding, Inc. for this amount.

This deal marks a significant expansion of Genmab’s oncology pipeline, adding Merus’s lead asset, petosemtamab, a late-stage bispecific antibody therapy currently in phase three development. Petosemtamab targets EGFR and LGR5, with the potential to be both first- and best-in-class in treating recurrent or metastatic head and neck squamous cell carcinoma. Phase two data presented at the 2025 ASCO Annual Meeting showed a 67 percent overall response rate when petosemtamab was combined with pembrolizumab, significantly outperforming the current standard of care.

Petosemtamab has received two ‘breakthrough therapy designations’ from the US Food and Drug Administration: one for previously treated head and neck cancer, and another for first-line treatment in PD-L1 positive patients.

According to Genmab, the addition of petosemtamab is a strategic fit that complements its expertise in antibody therapy development and commercialisation in oncology. The company anticipates interim readouts from one or both phase three trials in 2026, with a potential market launch in 2027, subject to regulatory approval.

Genmab expects the acquisition to strengthen its position in the competitive biotechnology sector. Analysts suggest the deal will accelerate Genmab’s transformation into a leading global biotech company, supporting sustained growth into the 2030s.

“Following the closing of the transaction, Genmab will have four proprietary programmes expected to drive multiple new drug launches by 2027,” the companies said in a joint statement. Genmab projects that petosemtamab could generate at least $1bn in annual sales by 2029, with scope for multibillion-dollar revenues thereafter.

“The proposed acquisition of Merus clearly aligns with our long-term strategy,” said Jan van de Winkel, president and chief executive of Genmab. “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. With our proven track record of success, both in clinical development and in commercialization, we are confident that we will be able to unlock the promise of petosemtamab.”

“We are excited for the opportunity to join Genmab, a leader in antibody therapeutics, to further develop and bring petosemtamab to patients,” said Bill Lundberg, president and chief executive of Merus. “Our two companies have a rich history of innovation with multiple approvals in the field of multispecific antibodies. We believe Genmab has the right vision and experience to advance petosemtamab in recurrent/metastatic head and neck cancer and beyond.

“I’m immensely proud of the Merus team who have pioneered our foundational platform technologies to make better medicines and who have demonstrated – with an approved product and a product candidate, petosemtamab, in registrational studies – an ability to deliver on our promise to close in on cancer,” he added.

The acquisition is part of Genmab’s strategic shift to a wholly-owned model. This approach was outlined in 2024 by Anthony Pagano, chief financial officer, who described the company’s transition from a royalty-based model to full ownership. The strategy aims to diversify Genmab’s revenue streams and support its evolution into a fully integrated biotechnology leader.

Richard Summerfield