Pfizer filed suit in Delaware against Metsera’s board and Novo Nordisk after Novo launched a counterproposal for obesity developer Metsera, seeking to block Metsera from terminating an earlier merger agreement with Pfizer. Pfizer alleges the Novo offer violates the terms of the September deal and fiduciary duties, and asked the court for a temporary restraining order to preserve its rights. Novo’s unconventional proposal — a large up‑front cash payment structured to offset regulatory delay risk — prompted Metsera to reopen talks and Novo to disclose a bid valuing Metsera near $6 billion. Pfizer says Novo’s structure is designed to evade antitrust review and argues it cannot qualify as a superior proposal because of regulatory risk. The dispute highlights strategic competition for next‑generation obesity assets and may affect timelines for any sale or integration.