Pfizer Sues Metsera and Novo Nordisk as Obesity Bid Battle Grows

Pfizer escalated a takeover battle over obesity biotech Metsera this week, suing Metsera and rival drugmaker Novo Nordisk after Novo submitted an unsolicited higher bid for the U.S. company that had already agreed to be acquired by Pfizer. Novo announced its offer late Thursday; Pfizer filed suit in the Delaware Court of Chancery on Friday and later added a federal antitrust complaint, seeking to block Metsera from terminating its agreement with Pfizer and to prevent Novo’s transaction from proceeding.

Novo offered $56.50 a share in cash, valuing Metsera at roughly $6 billion to $6.5 billion upfront, and included contingent payments of up to about $2.5 billion tied to clinical and regulatory milestones, which would raise the transaction’s potential total to roughly $8.5 billion to $9 billion. Pfizer’s earlier proposal, reached in September, committed $47.50 a share and up to $2.4 billion in additional payments, for a headline value of about $4.9 billion and a potential total near $7.3 billion. Metsera’s board has declared Novo’s proposal a superior company proposal, giving Pfizer a short window of four business days to improve its offer.

In court filings and public statements,...