Federal Trade Commission staff warned that Novo Nordisk’s proposed deal structure for a takeover of obesity biotech Metsera may violate the Hart‑Scott‑Rodino premerger review process, raising questions about whether substantial rights are being transferred before regulators can assess competitive harms. The FTC letter, authored by Daniel Guarnera of the Bureau of Competition, highlighted concerns that constraints on Metsera while a deal is pending could limit competition. The communication landed amid an escalating bidding war between Novo and Pfizer, with Novo’s latest offer valuing Metsera at roughly $10 billion. Pfizer has argued the deal would entrench Novo’s dominant position in GLP‑1 obesity drugs; Novo and Metsera disagree on the immediacy and legality of filing requirements. The FTC’s attention injects regulatory uncertainty into the transaction timetable and could prompt structural changes to how strategic acquisitions in the obesity drug space are executed.