Pfizer has escalated its fight for obesity biotech Metsera by filing suit against both Metsera and Novo Nordisk in the Delaware Court of Chancery on October 31.
The litigation challenges Novo’s bombshell $8.5 billion offer as legally superior to Pfizer’s original $7.2 billion deal announced in September.
Metsera’s board declared Novo’s bid superior after the Danish drugmaker outbid Pfizer by nearly $2 billion, sparking a high-stakes pharmaceutical turf war over access to the rapidly expanding obesity treatment market.
Pfizer is seeking a temporary restraining order to block deal termination and claims Novo’s proposal violates antitrust law.
The clash highlights intensifying competition for GLP-1 therapies as the obesity market races toward $150 billion in annual sales by 2030.
The regulatory advantage Pfizer now holds
Pfizer’s legal strategy hinges on one critical advantage: it already has antitrust clearance while Novo faces significant regulatory hurdles.
The Federal Trade Commission granted Pfizer early termination of Hart-Scott-Rodino review on October 31, more than a week ahead of the November 7 deadline.
Pfizer alleges Novo’s offer cannot qualify as “superior” because regulatory risks make completion unlikely—essentially arguing the deal cannot close on promised terms.
Pfizer emphasizes that its transaction is “ready to complete shortly following the Metsera stockholder meeting on November 13.”
The company also invokes competition law, calling Novo’s maneuver “an illegal attempt by a company with a dominant market position to suppress competition.”
This regulatory angle is powerful but risky. Pfizer must convince Delaware courts that Novo, already dominant in GLP-1 treatments with Wegovy and Ozempic, cannot secure approval for adding Metsera’s experimental therapies to its portfolio.
Battle for the next GLP-1 breakthrough
Metsera’s pipeline justifies the billion-dollar battle between pharmaceutical titans.
The company’s lead candidate, MET-097i, is a monthly-injectable GLP-1 that showed 14% average body-weight loss in interim Phase 2b results, exceeding weekly GLP-1 drugs’ typical 12% performance.
Metsera also develops an amylin analog that combines with GLP-1 and a chemically-stabilized oral GLP-1 formulation, addressing manufacturing scalability challenges plaguing competitors.
Analysts project peak sales reaching $5 billion for this pipeline.
For Pfizer, acquisition is essential because its own oral danuglipron candidate faced setbacks, leaving the company without obesity treatments despite having divested its consumer health division.
Novo, conversely, already dominates the space but seeks to recapture market share lost to Eli Lilly’s superior-performing tirzepatide.
The Tuesday deadline for Pfizer’s counteroffer and November 13 shareholder vote mean this legal battle will rapidly escalate, with Delaware courts potentially deciding whether competitive concerns or contractual commitments prevail.
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