Pfizer filed a Delaware court suit accusing Novo Nordisk of improperly disrupting its agreed acquisition of obesity biotech Metsera and seeking a temporary restraining order. Pfizer alleges Novo’s unsolicited structure is anticompetitive and not a feasible superior proposal. Novo publicly surfaced a higher, two-step offer valuing Metsera up to roughly $9 billion, prompting a rapid M&A showdown. The dispute centers on Metsera’s lead incretin and amylin candidates and the strategic value those programs offer in the obesity market. Pfizer argues regulatory and antitrust risk make Novo’s proposal unlikely to close; Novo contends its offer is superior in cash and milestones and aims to expand its weight-management franchise. The legal fight accelerates near-term pressure on rival bidders and could reshape deal tactics for high-value obesity assets.