Pfizer Sues Metsera and Novo Nordisk in Delaware, Alleging Breach of Merger Deal and Anticompetitive Conspiracy

Pfizer Inc. has escalated its battle with competitor Novo Nordisk A/S by filing a major lawsuit against both Metsera, Inc., its Board of Directors, and Novo Nordisk, S.A. The lawsuit, filed in the Delaware Court of Chancery, asserts claims of breach of contract, breach of fiduciary duty, and tortious interference in contract.

The legal action follows Novo Nordisk’s unsolicited, high-value competing bid for Metsera, which the Metsera Board has deemed a “Superior Company Proposal,” threatening to terminate its existing merger agreement with Pfizer.

Pfizer’s Core Legal Arguments

Pfizer’s claims center on the assertion that Novo Nordisk’s proposal does not legally qualify as a “Superior Company Proposal” under the terms of the original Pfizer-Metsera merger agreement:

Regulatory Risk: Pfizer argues that the Novo Nordisk transaction carries “significant regulatory risks”—risks that Metsera’s Board had previously found unacceptable in an earlier, similarly structured Novo Nordisk proposal. Pfizer contrasts this by noting it has already secured early termination of the waiting period under the Hart-Scott-Rodino Act (HSR clearance) from the U.S. Federal Trade Commission (FTC) and is prepared to close its deal shortly after the Metsera stockholder meeting on November 13.
Antitrust Evasion and Suppression of Competition: Pfizer’s lawsuit contends that the Novo Nordisk transaction is an “illegal attempt by a company with a dominant market position to suppress competition.” Novo Nordisk, the maker of blockbuster drugs like Wegovy and Ozempic, allegedly structured its bid—which includes a two-step payment and the use of non-voting shares—to deliberately evade antitrust review under the Clayton and Sherman Acts. Pfizer further accused Novo Nordisk of attempting to “capture and kill” an emerging U.S. competitor (Metsera).
Breach of Fiduciary Duty: The suit alleges that Metsera’s Board of Directors breached their fiduciary duties by:
- Accepting a proposal with known, unacceptable regulatory risks.
- Securing an indemnification provision from Novo Nordisk to protect themselves against potential unlawful conduct related to the transaction.
- The lawsuit also claims that a special dividend proposed under Novo Nordisk’s offer violates Delaware law.

Stakes in the Bidding War (The Obesity Market)

The fight over Metsera is highly charged because the company’s pipeline includes next-generation GLP-1 agonists for the lucrative obesity and diabetes markets, including potential once-a-month injectable and oral therapies.

Novo Nordisk’s Motivation: The current market leader is fighting to strengthen its pipeline and defend its dominance against rising competition, notably from Eli Lilly.
Pfizer’s Motivation: After shelving an internal oral obesity drug program earlier this year, Pfizer is betting on Metsera’s assets to rapidly re-enter and compete in the highly valuable weight-loss sector.

Pfizer’s Immediate Relief Sought

In addition to seeking injunctive relief and damages, Pfizer has filed a motion for a temporary restraining order to immediately block Metsera from terminating the merger agreement. Pfizer asserts it is “confident in the merits of its case” and is acting to “enforce and preserve its rights.”

Both Metsera and Novo Nordisk have publicly denied Pfizer’s claims, calling them “baseless” and promising to vigorously defend themselves in court.

Given the intense competition, the legal battle in the Delaware Court of Chancery is set to become one of the most closely watched corporate disputes in the pharmaceutical industry.