Novo Nordisk raised its offer for obesity biotech Metsera to as much as $10 billion, and the company’s board has flagged Novo’s proposal as a superior transaction. Simultaneously, Pfizer filed lawsuits alleging the deal structure and negotiations may violate antitrust and contract rules. The back-and-forth includes raised cash-and-contingent value offers and immediate legal action by Pfizer. The bids and legal filings were disclosed in company statements and court papers reported by BioCentury and MedCity News. The dispute foregrounds regulatory and antitrust risk for any deal involving a dominant GLP‑1 incumbent. Antitrust concerns could extend review timelines and complicate integration; deal terms include contingent payments and complex share exchanges that heighten legal scrutiny.