Pfizer Files Second Lawsuit Against Novo Nordisk and Metsera Amid Intensifying Bidding Battle Over Obesity Biotech

Pfizer announced on Monday that it has submitted a second lawsuit against Novo Nordisk and Metsera, arguing that the Danish pharmaceutical company’s effort to outbid Pfizer for the acquisition of the obesity-focused biotech is anticompetitive. According to the filing in the U.S. District Court in Delaware, Pfizer claims that the proposed transaction would reinforce Novo Nordisk’s dominant position in the rapidly expanding obesity drug market by eliminating a smaller challenger before it has the chance to compete. The filing further alleges that Metsera’s controlling shareholders cooperated with both the biotech and Novo Nordisk to undermine the existing agreement with Pfizer.

Novo Nordisk strongly rejected Pfizer’s accusations. In a statement issued on Monday, Ambre James Brown, the company’s vice president of global media, described Pfizer’s assertions as baseless and said the company’s intention is not to suppress innovation. She argued that Pfizer is choosing litigation as a tactic instead of competing on price, calling the legal action “highly unusual and seemingly desperate.” Brown added that Novo Nordisk’s proposal complies with all relevant regulations and is structured in a way that serves the interests of patients as well as Metsera’s shareholders.

Metsera also responded to Pfizer’s legal move, stating that Pfizer is attempting to use the courts to purchase the company at a lower price than the competing bid from Novo Nordisk. The biotech dismissed Pfizer’s claims as “nonsense” and stated that it will present its arguments in court.

This latest lawsuit deepens an already heated confrontation between the two pharmaceutical giants over Metsera, whose obesity drug pipeline could introduce new rivals into the competitive weight loss market. Pfizer first announced in September that it intended to acquire Metsera for $4.9 billion, with the value potentially rising to $7.3 billion depending on future milestone payments. For Pfizer, the acquisition represents a key opportunity to enter the booming sector after encountering difficulties in bringing its own obesity candidates to market.

However, Novo Nordisk escalated the situation last Thursday when it launched a takeover bid valuing Metsera at approximately $6 billion. The move triggered a four-business-day deadline for Pfizer to renegotiate its earlier offer. One day later, Pfizer filed its first lawsuit in the Delaware Court of Chancery, aiming to block Metsera from terminating its initial merger agreement with Pfizer. That complaint argued that Novo Nordisk’s proposal does not qualify as a superior offer because it faces substantial regulatory risks, making it unlikely to be finalized.

Novo Nordisk helped establish the modern weight loss drug category, developing highly effective GLP-1 treatments such as the diabetes injection Ozempic and the obesity therapy Wegovy. However, despite its early lead, the company has lost its dominant position over the past year to rival Eli Lilly and has struggled to reassure investors about the strength of its current pipeline.