Pfizer Inc. (NYSE: PFE) filed a lawsuit against Metsera Inc., its board of directors, and Novo Nordisk A/S in Delaware Court of Chancery, alleging breach of contract, breach of fiduciary duty, and tortious interference related to Metsera's merger agreement obligations.

The pharmaceutical company claims Novo Nordisk's competing offer does not qualify as a "Superior Company Proposal" under the merger agreement terms, citing significant regulatory risks that make completion unlikely. Pfizer received early termination of the Hart-Scott-Rodino waiting period from the Federal Trade Commission and states all regulatory approvals for its Metsera acquisition have been obtained.

According to the lawsuit, Novo Nordisk's proposal represents an attempt by a company with dominant market position to suppress competition using a structure designed to evade antitrust review. Pfizer alleges Metsera's board previously determined that Novo Nordisk's earlier proposal with identical structure posed unacceptable regulatory risks.

The lawsuit also challenges a proposed special dividend in Novo Nordisk's offer as a violation of Delaware law and accuses Metsera directors of breaching fiduciary duties by securing a self-interested indemnification provision from Novo Nordisk.

Pfizer filed a motion requesting a temporary restraining order to prevent Metsera from terminating the merger agreement. The company stated it "is taking this action to enforce and preserve its rights under the merger agreement" and expressed confidence in the case merits.

Metsera stockholders are scheduled to vote on the Pfizer acquisition on November 13. Pfizer seeks injunctive relief and damages to address alleged harm from Metsera's and Novo Nordisk's conduct.

The information was disclosed in a company press release dated October 31, 2025.