Pfizer filed suit in the Delaware Court of Chancery to block Metsera’s board from terminating a $4.9 billion merger agreement after Novo Nordisk surfaced with a higher, unconventional takeover proposal. Pfizer alleges Metsera’s board and Novo breached contractual and fiduciary duties and asks the court to bar Metsera from scrapping the deal while litigation proceeds. The dispute centers on Novo’s bid structure—an up‑front cash-heavy offer designed to offset regulatory timing risk—which Pfizer argues is not reasonably likely to close and improperly circumvents antitrust review. The legal escalation follows public bidding and rapid strategic maneuvering: Pfizer negotiated and secured Metsera’s initial acceptance in September, and Novo then publicly launched a counter that values Metsera substantially higher. Company statements and regulatory filings indicate both strategic urgency and heavy regulatory sensitivity in the obesity drug space, where Metsera’s portfolio of next‑generation weight‑loss assets has drawn intense interest from Big Pharma. The case will test deal‑protections, the definition of a “superior proposal,” and how courts treat innovative bid structures designed to mitigate antitrust timelines. Market participants should watch the court’s temporary‑relief decisions and any board disclosures; the outcome will influence M&A playbooks for contested deals in heavily regulated drug markets and could reshape how bidders structure offers to address regulatory delay risk.