Novo Nordisk increased its takeover proposal for obesity biotech Metsera, lifting its offer to as much as $10 billion and reshaping the competitive auction for a leading obesity-platform company. The move prompted immediate legal pushback from Pfizer, which alleges the counter-bid and related actions are anticompetitive and in breach of its prior merger agreement with Metsera. Legal filings filed in Delaware frame Pfizer’s response as an attempt to block a deal that it says would eliminate an emerging U.S. competitor in the GLP‑1 era. The bidding tussle has drawn intense scrutiny because Metsera’s pipeline and strategic position could materially affect competition in the obesity drug market. Litigation and regulatory risk now sit alongside deal valuation as determinative factors for any transaction’s completion timetable. Market participants and antitrust lawyers will watch whether court orders slow or halt the shifting offers and whether regulators weigh in on competitive concerns.