Pfizer sues Novo Nordisk over the Metsera bidding war

Pfizer filed a second lawsuit against Novo Nordisk on November 3, accusing the Danish drugmaker of trying to delay the biotech firm Metsera from bringing new obesity treatments to market rather than genuinely trying to buy the company ^[1]. The case, filed in U.S. District Court in Delaware, is the latest turn in a monthslong bidding war over Metsera, which is developing next-generation obesity drugs ^[1].

Pfizer agreed in September to pay up to $7.3 billion for Metsera after a private bidding contest with Novo ^[1]. Metsera had turned down Novo's offer six times, citing concerns that Novo already controlled a large share of the obesity-drug market and could face antitrust problems ^[1]. But after Novo's top investor overhauled the company's board last month, Novo returned with a new unsolicited bid worth about $9 billion ^[1]. Metsera then told Pfizer that Novo's offer was superior and gave Pfizer until Tuesday, November 4, to submit a higher bid ^[1].

Pfizer's new complaint focuses on the terms of Novo's proposed deal. It claims Novo's bid includes a 30-month "outside date" — the period before either side can walk away from the merger — which Pfizer says would stall Metsera's drugs from reaching the market for GLP-1 obesity treatments, a category Novo and Eli Lilly currently dominate ^[1]. By contrast, Pfizer says its own agreement with Metsera had a nine-month timeline and had already cleared early termination of U.S. antitrust review on October 31 ^[1]. Pfizer also alleges Novo's bid offers Metsera shareholders $6.5 billion upfront, before regulatory review is complete, paired with restrictive covenants that Pfizer says would delay or block Metsera's clinical work ^[1].

Novo Nordisk rejected the claims, saying it has closely followed all restrictions in Pfizer's existing merger agreement with Metsera and calling Pfizer's suggestion that Novo would impair a rising U.S. competitor "absurd" ^[1]. Novo said it plans to use its expertise to speed up, not slow down, the commercialization of Metsera's drugs for patients in the U.S. and elsewhere ^[1]. Metsera itself pushed back on Pfizer's newest suit, describing the allegations as "nonsense" and accusing Pfizer of trying to use litigation to drive down the price it has to pay ^[1]. Metsera also said Pfizer waited to sue even though it knew about Novo's bid on October 25 ^[1]. A Delaware Court of Chancery judge, Vice Chancellor Morgan Zurn, is set to review the competing claims at a hearing scheduled for Tuesday morning ^[1].

Markets reacted modestly Monday: Metsera shares fell 3.7% to close at $60.73, Novo shares dropped less than 1%, and Pfizer shares ended roughly flat ^[1].

Why it matters for patients

Metsera is working on obesity therapies designed for monthly injections, compared with the weekly dosing schedule used by Wegovy, Zepbound, and Mounjaro ^[1]. If that approach works out in further testing, it could eventually offer patients a less frequent dosing option, though these drugs are still in development and not yet available. Analysts cited in the reporting estimate Metsera's pipeline could generate roughly $5 billion in sales, while the broader obesity-drug market is projected to approach $150 billion a year ^[1]. How this legal fight ends could shape which company controls the timeline for bringing a new type of obesity drug to American patients, and how quickly. Right now, the drugs at the center of the dispute remain unapproved, so nothing about current prescriptions for Ozempic, Wegovy, Mounjaro, or Zepbound changes because of this lawsuit.

What happens next

A Delaware Court of Chancery hearing before Vice Chancellor Morgan Zurn was scheduled for Tuesday morning to weigh the competing claims ^[1]. Metsera had given Pfizer until Tuesday, November 4, to submit a higher bid after saying Novo's offer was superior ^[1]. No court ruling or final outcome on either the antitrust case or the takeover contest was reported in the source material.