The Battle for Metsera: Pfizer and Novo Nordisk Clash Over the Future of Obesity Treatment

The global pharmaceutical industry is witnessing one of its most significant takeover battles in recent years, centred on Metsera, a United States biotechnology company developing next-generation anti-obesity medicines. The two contenders are Pfizer, the New York based pharmaceutical giant seeking to re-establish itself in the weight loss market, and Novo Nordisk, the Danish powerhouse behind Ozempic and Wegovy, which already holds the upper hand.

The process began quietly on September 22, 2025, when Pfizer announced an agreement to acquire Metsera in a deal worth up to 7.3 billion dollars. The situation changed dramatically in late October when Novo Nordisk launched an unsolicited counteroffer valued at 10 billion dollars, setting off both a financial and legal confrontation. Pfizer has since taken the matter to court, arguing that Novo’s bid breaches United States antitrust law by attempting to suppress competition in a market expected to exceed 150 billion dollars by the early 2030s.

The motive for acquiring Metsera

Pfizer’s pursuit of Metsera stems from strategic necessity. The company has faced setbacks in its obesity research, most notably with its oral GLP 1 candidate danuglipron, which failed to meet expectations. Acquiring Metsera offers Pfizer a faster route back into the field, bypassing the lengthy early stages of drug development. Metsera’s leading asset, MET 097i, is a once monthly injectable GLP 1 medicine that has shown strong Phase 2 results, producing an average 14.1 per cent weight loss in trial participants. Its secondary compound, MET 233i, is an amylin analogue designed to complement GLP 1 therapy, potentially enhancing appetite suppression and metabolic control.

GLP 1 medicines mimic the body’s glucagon like peptide 1 hormone, which reduces hunger, slows digestion, and improves blood sugar regulation. Amylin influences satiety through a different pathway and combining the two mechanisms can produce greater efficacy. 

Metsera’s assets are considered ‘de-risked’ as their safety and effectiveness have already been demonstrated in human trials, allowing Pfizer to move into late-stage development with greater confidence and making the acquisition more compelling.

Furthermore, Metsera’s valuation has risen sharply, from roughly 5.5 billion dollars before Pfizer’s bid to the current 10-billion-dollar offer. Analysts highlight several factors behind this premium: substantial revenue potential, scientific differentiation, and the inclusion of contingent value rights (CVRs) worth up to 2.5 billion dollars. These CVRs mean that part of the total payment is dependent on achieving future clinical or regulatory milestones. They are a common mechanism in biotechnology deals, allowing buyers to mitigate risk while rewarding sellers if the drugs succeed commercially.

For Pfizer, Metsera would integrate neatly into its global operations. The company’s manufacturing and commercial infrastructure could scale new therapies rapidly across multiple markets, generating revenue synergies through faster and broader market penetration. Although some cost efficiencies could emerge, the main motivation is expansion rather than consolidation. Chief Executive Albert Bourla has described the deal as a strategic accelerator, enabling Pfizer to compete more effectively with Novo Nordisk and Eli Lilly, which currently dominate the obesity medicine market.

More critically, Novo Nordisk’s counterbid has significantly complicated the process. Pfizer’s lawsuits accuse Novo of attempting to suppress competition in violation of Section 7 of the United States Clayton Act, which prohibits mergers likely to lessen competition. A Delaware judge has already rejected Pfizer’s request for a temporary restraining order to prevent Metsera from ending the original merger agreement, though that ruling addressed only procedural matters. The case continues in federal court, where Pfizer has gained early encouragement from the Federal Trade Commission (FTC). The FTC has expressed concern that Novo’s complex multistep acquisition structure might allow it to bypass full antitrust review before closing.

Pfizer, by contrast, has already received preliminary clearance from the FTC for its own proposal, suggesting a clearer regulatory path. Metsera’s filings have noted that any deal with Novo Nordisk could face heightened scrutiny and potential delays of up to two years, or even a complete block. Pfizer now argues that Novo’s larger financial offer may be ‘illusory’ if it cannot gain regulatory approval, a claim it is emphasising in court as it seeks to uphold its initial agreement.

At this stage, Metsera’s fate depends less on financial negotiations and more on judicial interpretation. Pfizer is seeking an injunction to prevent Metsera from abandoning its contract, whilst also pursuing claims of breach of contract and interference. The outcome will not only determine which company secures Metsera but could also help define the boundaries of competition law in the fast-growing anti-obesity sector.