On 29 September 2025, Genmab A/S and Merus N.V. announced that they have entered into an agreement for Genmab to acquire all the shares of Merus in an all-cash transaction worth approximately USD 8 billion, with the deal anticipated to close early in the first quarter of 2026.
The deal will expand Genmab’s biologics portfolio to include Merus’ petosemtamab (MCLA-158), which is currently in Phase 3 development and has been granted two Breakthrough Therapy Designations by the FDA for recurrent or metastatic programmed death-ligand 1 (PD-L1) positive head and neck squamous cell carcinoma indications.