Pfizer Sues to Block Novo's $8.5–$9B Metsera Bid

Pfizer filed a second lawsuit in Delaware accusing Novo Nordisk, Metsera and Metsera’s controlling stockholders of antitrust violations, alleging Novo’s unsolicited roughly $8.5–$9 billion offer is an effort to capture and 'kill' a nascent U.S. competitor and preserve dominance in GLP‑1 obesity drugs. The complaint invokes Section 7 of the Clayton Act and Sections 1 and 2 of the Sherman Act, seeks injunctive relief, and contends Novo’s proposed transaction uses an unprecedented structure to evade antitrust review. The suit follows Pfizer’s September agreement to acquire Metsera for $4.9 billion upfront (up to $7.3 billion with contingent payments), and Pfizer says it has satisfied Hart‑Scott‑Rodino clearance requirements and is prepared to close after Metsera’s shareholder meeting. Metsera has said Novo’s unsolicited offer appears superior, and Metsera called Pfizer’s litigation a tactic to lower the purchase price; Novo has dismissed earlier claims as meritless or not immediately commented. The filings intensify a high‑stakes takeover battle over Metsera that could shape competition in the booming weight‑loss/GLP‑1 market.