Genmab to Acquire Merus in $8B Deal, Adding Breakthrough Oncology Asset to Late-Stage Pipeline
$8B acquisition brings late-stage bispecific antibody petosemtamab into Genmab’s pipeline, accelerating shift to a wholly owned model with potential blockbuster launches by 2027.
Genmab A/S (Nasdaq: GMAB) has announced plans to acquire Merus N.V. (Nasdaq: MRUS) in an all-cash transaction valued at approximately $8.0 billion, marking a major step in Genmab’s evolution toward a fully owned, late-stage pipeline model.
Under the agreement, Genmab will acquire all outstanding shares of Merus for $97.00 per share, a 41% premium over Merus’ September 26 closing price. The deal, unanimously approved by both companies’ boards, is expected to close in early Q1 2026 pending customary conditions, including a minimum 80% tender of shares.
Strategic fit: strengthening Genmab’s late-stage pipeline
The acquisition brings Merus’ petosemtamab, an EGFRxLGR5 bispecific antibody currently in Phase 3 trials for head and neck cancer, into Genmab’s portfolio. The asset has already received two Breakthrough Therapy Designations from the FDA and showed promising Phase 2 data at ASCO 2025, with both response rates and median progression-free survival outperforming standard of care.
Genmab expects petosemtamab to launch as early as 2027, subject to trial outcomes and regulatory approvals, with blockbuster potential and a forecast of at least $1 billion in annual sales by 2029. The company also plans to expand development into earlier lines of therapy and additional indications.
“This acquisition clearly aligns with our long-term strategy,” said Jan van de Winkel, Ph.D., President and CEO of Genmab. “Petosemtamab has the potential to be a transformational therapy for patients living with head and neck cancer. With our proven track record in clinical development and commercialization, we are confident we can unlock its promise while accelerating Genmab’s evolution into a global biotechnology leader.”
Bill Lundberg, M.D., President and CEO of Merus, added: “Genmab has the right vision and experience to advance petosemtamab in recurrent and metastatic head and neck cancer and beyond. I’m proud of the Merus team for pioneering our Multiclonics® platform and advancing a product candidate with the potential to make a real difference for patients.”
Financial details and outlook
The acquisition will be funded through a mix of cash on hand and approximately $5.5 billion in non-convertible debt financing underwritten by Morgan Stanley. Genmab expects the transaction to be EBITDA accretive by 2029, while maintaining its target to deleverage to under 3x gross leverage within two years of closing.
The transaction does not affect Genmab’s FY2025 guidance, with an updated 2026 outlook to be shared alongside year-end results in February 2026.
Industry impact
The deal underscores a broader industry trend of biopharma companies seeking to consolidate late-stage oncology assets with strong commercial potential. For Genmab, best known for its antibody expertise and collaborative business model, the acquisition of Merus signals a decisive pivot toward a wholly owned portfolio, with four proprietary programs on track to support multiple launches by 2027.
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BioFocus Newsroom