Pfizer filed suit in the Delaware Court of Chancery seeking to enforce its $4.9 billion merger agreement with obesity biotech Metsera and to block an unsolicited rival offer from Novo Nordisk. Pfizer alleges Metsera’s board and Novo breached contractual and fiduciary duties by treating Novo’s rival proposal as a “superior proposal” and asks the court to prevent Metsera from terminating the Pfizer deal. The litigation centers on an unconventional Novo offer structure that would deliver a large up‑front cash payment tied to half of Metsera’s shares; Pfizer argues that structure is designed to sidestep antitrust risk and is not reasonably likely to close. The dispute immediately raises deal‑making and regulatory questions in the fast‑moving obesity therapeutics market, where control of next‑generation weight‑loss assets is reshaping strategic priorities among big pharma. Market actors and potential bidders will watch the Delaware proceedings closely because the outcome could influence future takeover strategies for high‑value biotechs with breakthrough obesity and metabolic assets.